Polyoctenamer having silyl groups, production process and use in rubber mixtures

Abstract

The invention relates to a (cyclooctenyl)silane or an isomer mixture of (cyclooctenenyl)silanes as comonomer(s) which are used for production of a polyoctenamer and to the uses thereof in vehicle tyres.

Description

[0001] Polyoctenamer having silyl groups, production process and use in rubber mixtures

[0002] Polyoctenamer may be employed as an additive in tyres, rubber articles or adhesive compositions for example. The use of polyoctenamers in tyres makes it possible to improve processing and the properties of the tyres. However, there are several properties which require further improvement: rolling resistance, wet grip and abrasion resistance. These properties may be estimated by measuring three parameters in the laboratory: Loss factor tan 5 at 60°C and complex modulus E* at 0°C are determined by dynamic mechanical analysis, abrasion volume according to DIN ISO 4649, ISO 2781 . All three parameters must have values that are as low as possible. Improvement of one of these parameters often leads to deterioration of the two other parameters. It is an object of the present invention to produce an additive which has a positive effect on all three properties. This object can be achieved with a modified polyoctenamer, wherein the polyoctenamer bears silyl groups (>1 mol% of silyl groups based on the number of monomer units in the polymer) and has a high molar mass (Mn> 15 000 g / mol, Mw > 100 000 g / mol).

[0003] Functionalization of polyoctenamers with silyl groups has already been repeatedly described in the literature (DE2157405, DE4337191 , WO2015011404) but has always concerned silyl end groups where the silane groups are at the end of the polymer chain. With this method the content of silylated groups is limited: increasing this content automatically reduces the molar mass of the polyoctenamer. In practice, the content of silyl groups must remain well below 1 mol% in order that the molar mass of the polyoctenamer remains high enough for applications in tyres or other rubber products. It is an object of the present invention to synthesize a polyoctenamer which can simultaneously exhibit a high content of silyl groups (> 1 mol%) and a high molar mass (Mw > 50 000 g / mol). One option would theoretically be post-functionalization of the polymer. However, conventional silylation methods basically cannot be used for polyoctenamer. The hydrosilylation of a polymer has been described for liquid polybutadiene (US3470226) or polybutadiene having many vinyl side groups (WO2015086039) but this method cannot be used with high molecular weight linear polyoctenamer. Free-radical grafting of silanes analogously to WO2015153058 on polyoctenamer would lead to crosslinking of the polymer and cannot be used either for example.

[0004] The object of the present invention is achieved when a (cyclooctenyl)silane or an isomer mixture of (cyclooctenenyl)silanes is used as comonomer(s) for production of the polyoctenamer. These (cyclooctenyl)silanes may be produced for example by hydrosilylation of 1 ,5-cyclooctadiene (COD) with a silane, for example a halohydrogensilane or an alkoxyhydrogensilane, and optionally subsequent alcoholysis. The hydrosilylation of COD has already been described in the literature ([C.P. Pinazzi, J.C. Soutif, J.C. Brosse, Bull Soc Chim Fr 1974, 2166-2170], [R.M. Pike, P.M. McDonagh, J Chem Soc 1963, 2831-2833]) but the corresponding products / product mixtures were not purified and used as monomer for ring-opening metathesis.

[0005] The use of silyl-containing cyclobutene (US4396750) or silane-functionalized norbornene (US2008085979, [S. Karabulut, V. Sahin, B.O. Ozturk, Y. Imamoglu, J Inorg Organomet Polym 2009, 19, 570-574]) for production of silyl-functionalized polybutadiene or polynorbornene has previously been described. However, the synthesis of silyl-functionalized polyoctenamer from silyl-containing cyclooctene is to our knowledge unknown. The present invention provides polymers for use in rubber mixtures comprising units of formula (A) wherein at least one X represents a silyl unit of formula (S):

[0006] (S), wherein each R1is independently selected from the group consisting of alkyl group, preferably C1 -C10 alkyl group, and aryl group, and each Y is independently selected from the group consisting of halogen atom and -OR2, wherein R2is an alkyl group, an ether group or a polyether group and k is a number selected from 0, 1 , 2 and 3; all other X are hydrogen atoms; and h is an integer from 1 to 10 000.

[0007] It is preferable when 1 to 50 mol% of the monomer units contain an SiRkYs-k group, particularly preferably between 1 and 20 mol% of the monomer units.

[0008] The weight-average molar mass Mwof the polymer is preferably between 50 000 g / mol and 250 000 g / mol, particularly preferably between 100 000 g / mol and 200 000 g / mol.

[0009] The present invention further provides a process for producing the polymer (A) from a mixture of cyclooctene (II), 1 -silylcyclooctene (III), 3-silylcyclooctene (IV), 4-silylcyclooctene (V) and / or 5- silylcyclooctene (VI), wherein the mixture consists not only of cyclooctene.

[0010] (II) (HI) (IV) (V) (VI) wherein k = 0, 1 , 2 or 3, wherein R is an alkyl group having 1 to 16 carbon atoms, preferably methyl, ethyl, propyl, butyl, octyl or an aryl group having 6 carbon atoms, preferably a phenyl group, and Y is an alkoxy group having 1 to 5 carbon atoms, preferably methoxy, ethoxy or 2-methoxyethoxy, or a branched or unbranched C2-C30 alkyl ether group or a branched or unbranched C2-C30 alkyl polyether group or a halogen atom.

[0011] It is particularly preferable when the unit of formula (A) is selected from the group consisting of and mixtures of the foregoing.

[0012] Production of the polymer (A) employs for example a mixture of cyclooctene (II), 1 - triethoxysilylcyclooctene (VII), 3-triethoxysilylcyclooctene (VIII), 4-triethoxysilylcyclooctene (IX) and / or 5- triethoxysilylcyclooctene (X).

[0013] Silylated cyclooctenes having the structures (III) to (VI) can be produced by hydrosilylation of 1 ,5- cyclooctadiene (XI) and optionally subsequent alcoholysis:

[0014] The hydrosilylation is carried out with a catalyst, preferably a platinum-containing catalyst. Catalysts may be homogeneous Pt(O) complex catalysts, especially a Karstedt catalyst, a Speyer catalyst, hexachloroplatinic acid or a supported, i.e. heterogeneous, Pt catalyst, for example on activated carbon. Pt(O) catalysts may be dissolved in a solvent, preferably toluene or xylene. Additives may be added to the catalyst system, especially carboxylic acids such as benzoic acid, 3,5-ditertbutylbenzoic acid, 3,5- ditertbutyl-4-hydroxybenzoic acid, propionic acid and / or acetic acid.

[0015] The reaction is carried out at a temperature of 100°C to 400°C and under a pressure of 0.2 bar to 50 bar. The reaction may be performed with or without solvent. Byproducts which may be formed include doubly silylated cyclooctanes and hydrogenated products. These byproducts may be removed by distillation of the product mixture. The product or the product mixture may then be reacted with an alcohol to replace the halogen radicals of the silane with alkoxy groups. The reaction forms a strong acid (HCI, HBr or HI), which may optionally be neutralized by addition of a base.

[0016] The polyoctenamer (A) according to the invention may be produced by ring-opening metathesis of a mixture of at least one silyl-containing cyclooctene of structure (III) to (VI) and optionally cyclooctene (II). A catalyst must be added for this purpose. Suitable catalysts include for example tungsten complexes (US3597406, US4095033, DE2619197), molybdenum complexes (EP0218138; Polymer 1995, 36, 2787- 2796) and ruthenium complexes (J. Am. Chem. Soc. 1993, 115, 9858-9859; Macromolecules 1993, 26, 4739-4741). Ruthenium carbenes in particular are very widely applicable and tolerate all common chemical groups (EP0626402, US8324334, US2016 / 159942). Very particularly suitable are rutheniumcarbene complexes which, as one of their characteristic features, bear an N-heterocyclic carbene ligand. The polymerization reaction may be operated without solvent. Alternatively, the reaction may be performed in at least one solvent. Suitable solvents are nonpolar aromatic or aliphatic solvents, wherein aprotic nonpolar aliphatic solvents are preferred. Suitable solvents include for example saturated aliphatic hydrocarbons such as hexane, heptane, octane, nonane, decane, dodecane, cyclohexane, cycloheptane or cyclooctane; aromatic hydrocarbons such as benzene, toluene, xylene or mesitylene; halogenated hydrocarbons such as chloromethane, dichloromethane, chloroform or carbon tetrachloride; ethers such as diethyl ether, tetrahydrofuran or 1 ,4-dioxane; ketones such as acetone or methyl ethyl ketone; esters such as ethyl acetate; and mixtures of the aforementioned solvents. The solvent for the reaction is particularly preferably selected from the group consisting of alkanes having five to twelve carbon atoms, yet more preferably five to eight carbon atoms, and toluene. Also preferably selected are tetrahydrofuran, methyl ethyl ketone, chloromethane, dichloromethane, chloroform or mixtures thereof. Hexane or toluene are very particularly preferred, hexane being singled out in particular. The content of solvent may be adjusted, for example, to a value of 20% to 60% by weight, preferably of 40% to 60% by weight, based on the total weight of cycloalkene and solvent.

[0017] When choosing the solvents for the ring-opening metathesis reaction it should be noted that the solvent should not deactivate the catalyst or the catalytically active species. A person skilled in the art can identify this by simple experiments or by studying the literature.

[0018] The polymerization is preferably performed at temperatures of 20°C to 100°C, preferably 30°C to 80°C. The pressure in the synthesis apparatus is typically 1 to 7 bar. During the polymerization the monomer concentration is 0.1% to 60% by weight, preferably 20% to 50% by weight, in each case based on the total weight of the monomer mixture and catalyst and any chain transfer agents and solvents present.

[0019] Metal-containing catalysts are employed to catalyze the polymerization. Suitable metals include for example rhenium, ruthenium, osmium or mixtures thereof, wherein ruthenium-containing catalysts are preferred. Metal-carbene complexes bearing an N-heterocyclic carbene ligand are particularly suitable. Examples of suitable catalysts include

[0020] To terminate the polymerization alkyl vinyl ether / alkyl vinyl sulfide may be added. Suitable alkyl vinyl ethers are preferably selected from methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether and mixtures thereof. Preference is given to ethyl vinyl ether, butyl vinyl ether and mixtures thereof. Suitable alkyl vinyl sulfides are preferably selected from methyl vinyl sulfide, ethyl vinyl sulfide, propyl vinyl sulfide, butyl vinyl sulfide and mixtures thereof. Preference is given to ethyl vinyl sulfide, butyl vinyl sulfide and mixtures thereof. A ligand may also be added to stabilize the ruthenium complex. Suitable ligands contain heteroatoms such as N, O or S, for example pyridine, imidazole, N-methylimidazole, acetylacetone, acetonitrile, aminophenol.

[0021] After the synthesis the polyoctenamer (A) may be purified by membrane filtration to remove the catalyst, oligomers and other impurities for example. The membrane filtration may preferably be effected in an organic solvent. The membrane filtration is preferably an ultrafiltration.

[0022] The invention further provides rubber mixtures which are characterized in that they comprise at least one rubber and at least one copolymer according to the invention.

[0023] The process for producing a rubber mixture according to the invention comprises the process steps of i) initially charging at least one vulcanizable polymer; ii) adding Vulkanox® (Lanxess, Germany) to the vulcanizable polymer; iii) adding the polymer (A) according to the invention; iv) heating the mixture to a temperature of 140°C to 180°C to obtain the rubber mixture.

[0024] Synthetic rubbers as well as natural rubber are suitable for producing the rubber mixtures according to the invention. Preferred synthetic rubbers are described for example in W. Hofmann, Kautschuktechnologie [Rubber Technology], Genter Verlag, Stuttgart 1980. These include polybutadiene (BR), polyisoprene (IR), styrene / butadiene copolymers, for example emulsion SBR (E-SBR) or solution SBR (S-SBR), preferably having a styrene content of 1 to 60 wt%, particularly preferably 2 to 50 wt%, based on the overall polymer, chloroprene (CR), isobutylene / isoprene copolymers (HR), butadiene / acrylonitrile copolymers, preferably having an acrylonitrile content of 5% to 60% by weight, preferably 10% to 50% by weight, based on the overall polymer (NBR), partly hydrogenated or fully hydrogenated NBR rubber (HNBR), ethylene / propylene / diene copolymers (EPDM) or aforementioned rubbers additionally having functional groups, for example carboxyl, silanol or epoxy groups, for example epoxidized NR, carboxyl-functionalized NBR or silanol-functionalized (-SiOH) or siloxy-functionalized (-Si-OR), amino-, epoxy-, mercapto-, hydroxyl-functionalized SBR and mixtures of these rubbers. Of particular interest for the production of automobile tyre treads are anionically polymerized S-SBR rubbers (solution SBR) having a glass transition temperature above -50°C and mixtures thereof with diene rubbers. The rubber used may more preferably be NR or functionalized or unfunctionalized S-SBR / BR.

[0025] Fillers that may be employed for the rubber mixtures according to the invention include for example the following fillers:

[0026] Carbon blacks: The carbon blacks to be used here may be produced by the lamp black process, furnace black process, gas black process or thermal black process. The carbon blacks may have a BET surface area of 20 to 200 m2 / g. The carbon blacks may optionally also be doped, for example with Si.

[0027] Amorphous silicas, preferably precipitated silicas or formed silicas. The amorphous silicas may have a specific surface area of 5 to 1000 m2 / g, preferably 20 to 400 m2 / g (BET surface area) and a primary particle size of 10 to 400 nm. The silicas may optionally also take the form of mixed oxides with other metal oxides, such as Al, Mg, Ca, Ba, Zn and titanium oxides.

[0028] Synthetic silicates, such as aluminium silicate or alkaline earth silicates, for example magnesium silicate or calcium silicate. The synthetic silicates having BET surface areas of 20 to 400 m2 / g and primary particle diameters of 10 to 400 nm.

[0029] Synthetic or natural aluminium oxides and hydroxides.

[0030] Natural silicates, such as kaolin and other naturally occurring silicas.

[0031] Glass fibres and glass-fibre products (mats, strands) or glass microbeads.

[0032] It is possible with preference to use amorphous silicas, more preferably precipitated silicas or silicates, especially preferably precipitated silicas having a BET surface area of 20 to 400 m2 / g in amounts of 5 to 180 parts by weight in each case based on 100 parts of rubber.

[0033] The fillers mentioned may be used alone or in admixture.

[0034] The rubber mixtures according to the invention may comprise further rubber auxiliaries, such as reaction accelerators, ageing stabilizers, heat stabilizers, light stabilizers, antiozonants, processing aids, plasticizers, resins, tackifiers, blowing agents, dyes, pigments, waxes, extenders, organic acids, retarders, metal oxides and activators, such as diphenylguanidine, triethanolamine, polyethylene glycol, alkoxy-terminated polyethylene glycol alkyl-O-(CH2-CH2-O)yi-H where yl = 2-25, preferably yl = 2-15, particularly preferably yl = 3-10, very particularly preferably yl = 3-6, or hexanetriol, as are familiar to the rubber industry.

[0035] The rubber auxiliaries may be used in familiar amounts determined by factors including the end use. Customary amounts may, for example, be amounts of 0.1% to 50% by weight based on rubber. Crosslinkers used may be peroxides, sulfur or sulfur donor substances. The rubber mixtures according to the invention may further comprise vulcanization accelerators. Examples of suitable vulcanization accelerators may be mercaptobenzothiazoles, sulfenamides, thiurams, dithiocarbamates, thioureas and thiocarbonates. The vulcanization accelerators and sulfur may be used in amounts of 0.1% to 10% by weight, preferably 0.1% to 5% by weight, based on 100 parts by weight of rubber.

[0036] The rubber mixtures according to the invention can be vulcanized at temperatures of 100°C to 200°C, preferably 120°C to 180°C, optionally at a pressure of 10 to 200 bar. The blending of the rubbers with the precipitated silica according to the invention, any rubber auxiliaries and the silane may be conducted in known mixing units, such as rollers, internal mixers and mixing extruders.

[0037] The rubber mixtures according to the invention may be used for production of moulded articles, for example for production of tyres, especially pneumatic tyres or parts of such tyres, for example tyre treads and tyre sidewalls or tyre carcass mixtures, cable sheaths, hoses, drive belts, conveyor belts, roller coverings, footwear soles, sealing rings and damping elements. Preferably for tyres selected from the group consisting of tyres for vehicles, especially commercial vehicles, motorcycles and high-speed vehicles, containing the or produced with or from the rubber mixture according to the invention or the polymer according to the invention.

[0038] Examples:

[0039] Weight-average molecular weight

[0040] Determination of molecular weight was carried out by gel permeation chromatography (GPC) as per DIN 55672-1 :2016-03. Measurements were performed with a GPC system from Knauer Wissenschaftliche Gerate GmbH. The polymer was measured as a solution in tetra hydrofuran (c = 5 g / L, injection volume 100 pL) on an SDV column (30 cm, 5 pm, linear) with pre-column (SDV 5 cm, 5 pm, 100 A) at 23°C and a flow rate of 1 mL / min. Calculation of the average molar masses was carried out by means of the strip method against polystyrene standards. WinGPC UniChrom (Build 5350) software from PSS Polymer Standards Service GmbH was employed for evaluation.

[0041] Melting point and melting enthalpy

[0042] Determination of melting point and melting enthalpy was carried out by differential scanning calorimetry (DSC). Polymer samples between 5 and 10 mg were measured. Measurements were performed on a PerkinElmer DSC-7 instrument with 20 mL / min of nitrogen 5.0 as purging gas. The measurement program contained a first heating from -90°C to 80°C (heating rate 20 K / min), a cooling from 80°C to - 90°C (cooling rate 20K / min) and a second heating from -90°C to 80°C (heating rate 20 K / min). The melting point and the melting enthalpy of the polyalkenamers was determined using the second heating.

[0043] Example A: Production of triethoxysilylcyclooctene (isomer mixture)

[0044] Cyclooctadiene (180 g; 1 .66 mol; 1 .00 eg.), trichlorosilane (248 g; 1 .83 mol; 1.10 eg.) and Karstedt catalyst (2.00 g; 20% by weight of Pt) were initially charged in a stainless steel autoclave and pressurized with 1 bar of nitrogen. The reaction mixture was then heated to 360°C and 35 bar over a period of 1 h. The reaction mixture was then allowed to cool to room temperature. The crude product was purified by distillation (85-100°C, 7-9 mbar) and trichlorosilylcyclooctene (290.05 g; 1.19 mol; 72% yield) was obtained as an isomer mixture. The isomer mixture of trichlorosilylcyclooctene (290.05 g; 1.19 mol; 1.0 eq.) was dissolved in toluene (2.2 L) and triethylamine (401 .17 g; 3.96 mol; 3.33 eq.) was added. Ethanol (201 .29 g; 4.37 mol; 3.67 eq) was then added at -10-0°C over 2.5 h. The reaction mixture is allowed to warm up to room temperature and then filtered. The volatile constituents were removed under reduced pressure and the crude product was purified by distillation (1.0 x 103mbar, 73°C). Triethoxysilylcyclooctene (191.54 g; 0.703 mol; 59% yield) was obtained as a colourless liquid.

[0045] This was an isomer mixture of 75 mol% of 3-triethoxysilylcyclooctene (VIII), 12 mol% of 5- triethoxysilylcyclooctene (X), 11 mol% of 4-triethoxysilylcyclooctene (IX) and 2 mol% of 1- triethoxysilylcyclooctene (VII).

[0046] Example B1 (comparative example): Production of polyoctenamer without silyl groups

[0047] 850 mL of toluene, 500 g of cyclooctene (COE) and 7.4 mg of vinylcyclohexene (VCH) were charged into a dry 2 L glass reactor fitted with a mechanical stirrer under argon. The reaction mixture was heated to 60°C and a solution of 80 mg of tricyclohexylphosphine[1 ,3-bis(2,4,6-trimethylphenyl)-4,5- dimethylimidazol-2-ylidene](2-thienylmethylidene)ruthenium(ll) dichloride (catalyst C3) in 18 mL of toluene was added. A temperature increase of 15°C was observed and the reaction mixture became markedly more viscous. 30 min after the catalyst addition, 4.5 g of butyl vinyl ether and 2 g of Irganox 1010 were added and the reaction mixture was discharged from the reactor after a further 30 min.

[0048] The reaction mixture was diluted with 4.5 L of toluene and purified with an ultrafiltration membrane. This required 15 L of fresh toluene for the filtration process.

[0049] The purified polymer solution was then dried in an aluminium dish in a vacuum drying cabinet over 20 h at 100°C and a vacuum of 1 mbar after inertization with nitrogen. 450 g of white solid were obtained. The NMR spectrum of the solid corresponded to the expected structure of a polyoctenamer containing 0.30 mol% of vinyl end groups and 0.32 mol% of cyclohexene end groups based on the number of monomer units.

[0050] 1 H NMR (CDCI3, 500 MHz, 30°C) 5 (ppm): Polyoctenamer: 5.38, 5.34, 2.01 , 1.96, 1.30; end groups: 5.81 (m, 1 H, CH2=CH-CH2-), 5.66 (d, 2H, CH2-CH=CH-CH2), 5.38-5.34 (m, 2H, -CH-CH=CH-CH2), 4.95 (m, 2H, CH2=CH-CH2-).

[0051] Melting point: 57°C

[0052] Molar mass Mn21 000 g / mol, Mw: 114 000 g / mol

[0053] Example B2 (inventive): Production of copolymer of 97.2 mol% of cyclooctene and 2.8 mol% of triethoxysilylcyclooctene

[0054] 155 mL of toluene, 53.4 g of cyclooctene (COE), 4.1 g of isomer mixture of triethoxycyclooctene from example A and 189 mg of vinylcyclohexene (VCH) were charged into a dry 500 mL glass reactor fitted with a mechanical stirrer under argon. The reaction mixture was heated to 60°C and a solution of 22 mg of tricyclohexylphosphine[1 ,3-bis(2,4,6-trimethylphenyl)-4,5-dimethylimidazol-2-ylidene](2- thienylmethylidene)ruthenium(ll) dichloride (catalyst C3) in 5 mL of toluene was added. A temperature increase of 18°C was observed and the reaction mixture became markedly more viscous. 1 h after the catalyst addition, 0.5 g of butyl vinyl ether and 0.25 g of Irganox 1010 were added and the reaction mixture was discharged from the reactor after a further 30 min.

[0055] The reaction mixture was diluted with 600 mL of toluene and purified with an ultrafiltration membrane. This required 5 L of fresh toluene for the filtration process.

[0056] The purified polymer solution was then dried in an aluminium dish in a vacuum drying cabinet over 20 h at 100°C and a vacuum of 1 mbar after inertization with nitrogen. 45 g of white solid were obtained. The NMR spectrum of the solid corresponded to the expected structure of a polyoctenamer containing 2.8 mol% of triethoxysilyl groups, 0.19 mol% of vinyl end groups and 0.30 mol% of cyclohexene end groups based on the number of monomer units.

[0057] The solid is therefore a copolymer of structure (A), wherein 2.8 mol% of the monomer units contain a triethoxysilyl group.

[0058] 1 H NMR (CDCI3, 500 MHz, 30°C) 5 (ppm): Polyoctenamer: 5.38, 5.34, 2.01 , 1.96, 1.30; triethoxysilyl groups: 3.84 (m, 6H, CH3-CH2-O-Si), 1.18-1.12 (m, 9H, CH3-CH2-O-Si); end groups: 5.81 (m, 1 H, CH2=CH-CH2-), 5.66 (d, 2H, CH2-CH=CH-CH2), 5.38-5.34 (m, 2H, -CH2-CH=CH-CH2), 4.95 (m, 2H, CH2=CH-CH2-).

[0059] Melting point: 54°C

[0060] Molar mass Mn= 21 000 g / mol, Mw: 142 000 g / mol

[0061] Example B3 (inventive): Production of copolymer of 93 mol% of cyclooctene and 7 mol% of triethoxysilylcyclooctene

[0062] 540 mL of toluene, 215 g of cyclooctene (COE), 59.1 g of isomer mixture of triethoxycyclooctene from example A and 750 mg of vinylcyclohexene (VCH) were charged into a dry 500 mL glass reactor fitted with a mechanical stirrer under argon. The reaction mixture was heated to 60°C and a solution of 100 mg of tricyclohexylphosphine[1 ,3-bis(2,4,6-trimethylphenyl)-4,5-dimethylimidazol-2-ylidene](2- thienylmethylidene)ruthenium(ll) dichloride (catalyst C3) in 22 mL of toluene was added. A temperature increase of 19°C was observed and the reaction mixture became markedly more viscous. 1 h after the catalyst addition, 2.2 g of butyl vinyl ether and 1 g of Irganox 1010 were added and the reaction mixture was discharged from the reactor after a further 30 min.

[0063] The reaction mixture was diluted with 4.5 L of toluene and purified with an ultrafiltration membrane. This required 15 L of fresh toluene for the filtration process.

[0064] The purified polymer solution was then dried in an aluminium dish in a vacuum drying cabinet over 20 h at 100°C and a vacuum of 1 mbar after inertization with nitrogen. 260 g of white solid were obtained. The NMR spectrum of the solid corresponded to the expected structure of a polyoctenamer containing 6.6 mol% of triethoxysilyl groups, 0.12 mol% of vinyl end groups and 0.24 mol% of cyclohexene end groups based on the number of monomer units. The solid is therefore a copolymer of structure (A), wherein 6.6 mol% of the monomer units contain a triethoxysilyl group.

[0065] 1 H NMR (CDCI3, 500 MHz, 30°C) 6 (ppm): Polyoctenamer: 5.38, 5.34, 2.01 , 1.96, 1.30; triethoxysilyl groups: 3.84 (m, 6H, CH3-CH2-O-Si), 1.18-1.12 (m, 9H, CH3-CH2-O-Si); end groups: 5.81 (m, 1 H, CH2=CH-CH2-), 5.66 (d, 2H, CH2-CH=CH-CH2), 5.38-5.34 (m, 2H, -CH2-CH=CH-CH2), 4.95 (m, 2H,

[0066] CH2=CH-CH2-).

[0067] Melting point: 48°C

[0068] Molar mass Mn= 27 000 g / mol, Mw: 154 000 g / mol

[0069] Production of rubber compounds (examples CO to C3)

[0070] To evaluate the use of the different polyoctenamers from examples B1 to B3 in tyre applications, various rubber mixtures were produced and tested. Example CO is a rubber mixture without polyoctenamer. Example C1 is a rubber mixture composed of the noninventive polyoctenamer B1. Examples C2 and C3 are rubber mixtures composed of the inventive polyoctenamers B2 and B3.

[0071] The general process for producing rubber mixtures and vulcanizates thereof is described in the following book: “Rubber Technology Handbook”, W. Hofmann, Hanser Verlag 1994. The vulcanization time for the test specimens at 165°C is in each case 20 min for all mixtures produced.

[0072] The materials used and the formulations used for the rubber mixtures (standard green tyre) are reported in table 1 which follows. The unit “phr” is to be understood as meaning parts by weight based on 100 parts of the employed raw rubber. The rubber mixtures were produced with a W&P GK 1 .5 N internal mixer from Harburg Freudenberger Maschinenbau GmbH according to the mixing procedure described in table 2. Test methods used for the mixtures and vulcanizates thereof were effected according to table 3.

[0073] Table 4 which follows specifies the performance data of examples C0-C3 which have been compounded according to tables 1 -3 and tested.

[0074] Table 1 : Green tyre formulation

[0075]

[0076]

[0077] 1Buna® VSL 4526-2 HM is a solution styrene-butadiene rubber extended with 37.5 phr of TDAE oil; Mooney (ML(1 +4) at 100°C) : 62 ME; vinyl : 44.5%; styrene 26%.

[0078] 2Buna® CB 24 (cis-1 ,4 > 96%); neodymium-catalysed butadiene rubber; Mooney (ML (1+4) at 100°C): 44 ME

[0079] Table 2: Mixing procedure

[0080] Table 3: Test methods

[0081] Table 4: Performance data

[0082] These test results show that the polymers of the invention (examples B2 and B3) show improvements in tyre tread mixtures compared to polyoctenamers from the prior art (example B1).

[0083] Thus the loss factors for the inventive mixtures from examples C2 and C3, as a laboratory indicator for the rolling resistance of a tyre fitted with such a tread, are advantageously reduced, thus predicting lower fuel consumption of a vehicle fitted with such tyres. Furthermore, the complex moduli E* at 0°C for examples C2 and C3 are advantageously reduced compared to mixtures CO and C1 . This can generally be regarded as a laboratory indicator for better winter characteristics.

[0084] In addition, the volume losses for the inventive examples in the abrasion test are also at least equivalent, if not reduced, compared to the prior art.

Claims

Claims1 . Polymer for use in rubber mixtures comprising independently selected units of formula (A)wherein at least one X represents a silyl unit of formula (S):(S),wherein each R1is independently selected from the group consisting of alkyl group, preferably C1 -C10 alkyl group, and aryl group, and each Y is independently selected from the group consisting of halogen atom and -OR2, wherein R2is an alkyl group, an ether group or a polyether group and k is a number selected from 0, 1 , 2 and 3; all other X are hydrogen atoms; and h is an integer from 1 to 10 000.

2. Polymer according to Claim 1 , characterized in that the unit according to formula (A) is selected from the group consisting ofand mixtures of the foregoing.

3. Polymer according to either of the preceding claims, characterized in that k = 0 and Y = OR2, wherein R2is an alkyl group, preferably a C1-C5-alkyl group.

4. Polymer according to any of the preceding claims, characterized in that the polymer comprises g units of formula (B)wherein g is an integer from 1 to 10 000.

5. Polymer according to Claim 4, characterized in that it conforms to formula (G):wherein g is an integer between 0 and 10 000RAis an organic radical, RAis preferably selected from the group consisting of H, alkyl group, alkenyl group, cycloalkyl group, cycloalkenyl group and aryl group; andREis an organic radical, REis preferably selected from the group consisting of H, alkyl group, alkenyl group, cycloalkyl group, cycloalkenyl group and aryl group.

6. Polymer according to either of Claims 4 and 5, characterized in that the polymer comprises 1 to100, preferably 5 to 100, units of formula (G) for each unit of formula (A).

7. Polymer according to any of the preceding Claims 1 to 6, characterized in that the weight-average molar mass Mwof the polymer is 50 000 g / mol-250 000 g / mol, more preferably 100 000 g / mol-200 000 g / mol.

8. Polymer according to any of the preceding claims, characterized in that the polymer has a random facticity.

9. Process for producing the polymer according to any of the preceding claims comprising the process steps of:I. providing at least one silylated (cyclooctenyl)silane according to any of formulae (III), (VI), (V), (VI) or mixtures of the foregoing:II. polymerizing the at least one (cyclooctenyl)silane, optionally with 1 ,5-dicyclooctadiene or cyclooctene, preferably by ring-opening metathesis, to obtain the polymer according to any of Claims 1 to 9.

10. Process according to Claim 9, characterized in that the at least one (cyclooctenyl)silane according to any of formulae (III), (IV), (V), (VI) or mixtures of the foregoing are provided by hydrosilylation of 1 ,5-cyclooctadiene.11 . Polymer obtainable according to either of Claims 9 and 10.

12. Rubber mixture comprising at least one polymer according to any of Claims 1 to 8.

13. Process for producing a rubber mixture according to Claim 12 comprising the process steps of: i) initially charging at least one vulcanizable polymer; ii) adding Vulkanox® to the vulcanizable polymer; iii) adding the polymer according to any of Claims 1 to 9; iv) heating the mixture to a temperature of 140°C to 180°C to obtain the rubber mixture according to Claim 12.

14. Adhesive mixture comprising at least one polymer according to any of Claims 1 to 8.

15. Article, preferably tyre, especially tyre selected from the group consisting of tyres for vehicles, especially commercial vehicles, motorcycles and high-speed vehicles, containing the or produced with or from the rubber mixture according to Claim 12 or the polymer according to any of Claims 1 to 8 or 11 .

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