CA2361965A1 - Rubber mixtures based on amino-isoprene polymers and their use in the production of tire treads with low rolling resistance - Google Patents
Rubber mixtures based on amino-isoprene polymers and their use in the production of tire treads with low rolling resistance Download PDFInfo
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- CA2361965A1 CA2361965A1 CA002361965A CA2361965A CA2361965A1 CA 2361965 A1 CA2361965 A1 CA 2361965A1 CA 002361965 A CA002361965 A CA 002361965A CA 2361965 A CA2361965 A CA 2361965A CA 2361965 A1 CA2361965 A1 CA 2361965A1
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F236/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds
- C08F236/02—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds
- C08F236/04—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F236/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds
- C08F236/02—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds
- C08F236/04—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated
- C08F236/14—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated containing elements other than carbon and hydrogen
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/80—Technologies aiming to reduce greenhouse gasses emissions common to all road transportation technologies
- Y02T10/86—Optimisation of rolling resistance, e.g. weight reduction
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- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
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Abstract
The invention relates to rubber mixtures based on homopolymers and copolymer s of special amino-isoprenes and fillers as well as to their vulcanizates. Sai d rubber mixtures and vulcanizates are suitable for the production of fully reinforced, abrasion-resistant moulded parts, notably tires with low rolling resistance and high abrasion resistance.
Description
Le A 33 468 - foreign CA 02361965 2001-08-O1 Bglby/NT
Rubber comyounds based on aminoisoprene nolymers and the use thereof for the uroduction of tyre treads which exhibit a low rolling resistance The present invention relates to rubber compounds based on homo- and copolymers of special aminoisoprenes and fillers, and relates to vulcanised products thereof. The rubber compounds according to the invention or the vulcanised products thereof are suitable for the production of highly reinforced, abrasion-resistant mouldings, particularly for the production of tyres which exhibit a low rolling resistance and a high abrasion-resistance.
Compared with corresponding emulsion rubbers, anionically polymerised solution rubbers which contain double bonds, such as solution polybutadiene and solution styrene/butadiene rubbers, exhibit advantages for the production of tyre treads which exhibit a low rolling resistance. Amongst others, these advantages are the facility of controlling the vinyl content and the glass transition temperature which is associated therewith, and of controlling the extent of molecular branching. In practical application, this results in particular advantages in the relationship between the wet-slip resistance and the rolling resistance of the tyres. Thus US-PS 5 227 425 describes the production of tyre treads from a solution SBR rubber and hydrated silica.
In order to achieve a further improvement in properties, numerous methods have been developed for modifying the terminal groups, such as that which employs dimethylaminopropyl-acrylamide and which is described in EP-A 334 042, or such as that which employs silyl ethers and which is described EP-A 447 066. However, due to the high molecular weight of rubbers, the proportion by weight of terminal groups is low, and is therefore only capable of exerting a slight effect on the interaction between a filler and a rubber molecule. The object of the present invention was therefore to produce solution rubbers having a considerably higher content of amino groups.
US-PS 3 544 532 describes cationically unsaturated polymers, for the production of which polymers of 2-dialkylaminomethyl-1,3-butadiene are used, amongst other LeA33468 substances. These polymers are produced by emulsion polymerisation or by subsequent reactions analogous to polymerisation, and therefore have a microstructure (1,2-vinyl content, long-chain branching, molecular weight distribution, distribution of the copolymer in the monomer) which differs from that of the anionically initiated solution polymers of the present invention. The aforementioned US Patent does not mention of the use of these rubbers for tyres.
Emulsion rubbers which are produced from dimes and vinyl monomers which contain amino groups, and the use thereof in tyre treads filled with hydrated silica, are known from EP 819 731. However, due to the production of these rubbers under conditions of radical-initiated polymerisation, the known advantages of anionically polymerised solution rubbers cannot be achieved, as mentioned above. lvloreover, the monomers used there are structurally different from the dialkylaminoisoprene monomers of the present invention.
The object of the present invention was therefore to provide compounds comprising rubbers which contain amino groups, from which tyres can be produced which exhibit improved wet slip-resistance as well as high mechanical strength and improved abrasion behaviour.
The present invention therefore relates to rubber compounds consisting of a rubber and 10 to 500 parts by weight, preferably 20 to 200 parts by weight, of a filler with respect to 100 parts by weight rubber, wherein the rubber has been produced by polymerisation in solution and has a content of aminoisoprenes, which are incorporated by polymerisation, of formula Rz R~-N
wherein Le A 33 468 RI and RZ, independently of each other, represent CI-C~8 alkyl- or CS-C12 cycloalkyl radicals, which can optionally be interrupted by one or more 'nitrogen, oxygen and/or sulphur atoms or which jointly form a ring, and also represent C6-Cg aryl- or C~-C24 alkylaryl radicals, from 0.01 to 100 % by weight, preferably 0.1 to 10 % by weight, a content of diolefines from 0 to 99.99 % by weight, preferably 55 to 99.9 % by weight, and a content of aromatic vinyl monomers, incorporated by polymerisation, from 0 to by weight, preferably 0 to 45 % by weight, with respect to the solution rubber in each case, and has a (number average) molecular weight from 10,000 to 2,000,000 and in addition has a glass transition temperature from -100°C to +20°C.
Aminoisoprenes which are suitable for polymerisation and which are particularly preferred have the following structures:
~Hs NCH ~zHs ~~Hs N a N~..CzHs N,-CHs a) b) c) n-C H CaH~ pz~"~zs N~n~CaH~ ~~j_Ca~r N--CH3 ) ~O /--NCH3 ~NCzHs N~ N~~ N
g) h) i) ' CA 02361965 2001-08-O1 Le A 33 468 CHs N N~O~C~
.1) k) 1) H
N
m) n) Examples of aromatic vinyl monomers which can be used for polymerisation include styrene, o-, m- and p-methylstyrene, p-tert.-butylstyrene, a-methylstyrene, vinylnaphthalene, divinylbenzene, trivinylbenzene and/or divinylnaphthalene.
Styrene is most preferably used.
Diolefines which can be used for polymerisation according to the invention include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 1-vinyl-1,3-butadiene and/or 1,3 -hexadiene. 1,3-butadiene and isoprene are most preferably used.
The rubbers based on aminoisoprene monomers and optionally other diolefines and aromatic vinyl monomers which can be used according to the invention preferably have average (number average) molecular weights from 100,000 to 1,000,000, glass transition temperatures which preferably range from -40°C to 0°C, and Mooney viscosities ML 1+4 (100°C) from 10 to 200, preferably from 30 to 150.
Le A 33 468 The aminoisoprenes can be produced by methods known in the art: for example from 2-chloromethyl-1,.3-butadiene and secondary amines as described in US
3,544,532, or from secondary amines, formaldehyde, allyl alcohol, dimethyl sulphoxide and potassium-tert.-butylate as described in Angew. Chem. 102 (1990) 929. The structure of the secondary amines which can be used can be varied within wide limits.
The aminoisoprene-based rubbers according to the invention are produced by anionic solution polymerisation. i.e. by means of a catalyst based on alkali metals, preferably in an inert hydrocarbon as a solvent. The known randomising agents and control agents for the microstructure of the polymer can be used in addition. Anionic solution polymerisation methods of this type are known, and are described, for example, by I.
Franta in Elastomers and Rubber Compounding Materials; Elsevier 1989. pages 73-74. 92-94 and in Houben-Weyl, Methoden der Organischen Chemie, Thieme Verlag, Stuttgart, 1987, Volume E 20, pages 114 - 134.
Examples of suitable alkali metal catalysts include lithium, sodium, potassium, rubidium, and caesium metals and hydrocarbon compounds thereof, as well as com-plex compounds thereof with polar organic compounds.
Lithium and sodium hydrocarbon compounds comprising 2 to 20 carbon atoms are particularly preferred, for example ethyllithium, n-propyllithium, i-propyllithium, n-butyllithium, sec-butyllithium, tetr.-octyllithium, n-decyllithium, phenyllithium, 2-naphthyllithium, 2-butylphenyllithium, cyclohexyllithium, 4-cyclopentyllithium, 1,4-dilithiobutene-2, sodium naphthalene, sodium biphenyl, potassium tetrahydrofuran complex, potassium diethoxyethane complex, and sodium tetramethylethylene-diamine complex. These catalysts can be use on their own or in admixture.
The amounts of catalyst range from 0.1 to 10 mmol /100 g polymer, preferably from 0.5 to 5 mmol/100 g polymer.
Anionic solution polymerisation is preferably conducted in a hydrocarbon, but can also be conducted in another solvent which does not destroy the catalyst, for example Le A 33 468 in tetrahydrofuran, tetrahydropyran or 1,4-dioxane. Example of hydrocarbons which are suitable as solvents include aliphatic, cycloaliphatic or aromatic hydrocarbons comprising 2 to 12 carbon atoms. The preferred solvents are propane, butane, pentane, hexane, cyclohexane, propene, butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, benzene, toluene and xylene. The solvents can be used on their own or in admixture.
The appropriate amount of solvent can easily be determined by preliminary tests.
The polymers, which can be produced by anionic solution polymerisation, can also be "coupled" by known methods, for example by means of disulphur dichloride or by the reaction of the live polymer anion with silicon tetrachloride.
Suitable fillers for the rubber compounds according to the invention include all fillers which are known and used in the rubber industry, comprising both active and inactive fillers.
Examples thereof include:
- microdispersed hydrated silicas, for example those produced by precipitation from solution of silicates or by the flame hydrolysis of silicon halides having specific surfaces from 5 - 1000, preferably 20-400 m2/g (BET specific surface) and having primary particle sizes from 10-400 nm. The hydrated silicas may optionally also exist as mixed oxides with other metal oxides such as AI, Mg, Ca, Ba, Zn, Zr or Ti oxides;
- synthetic silicates such as aluminium silicate, or alkaline earth silicates such as magnesium silicate or calcium silicate, which have BET specific surfaces from 20-400 m2/g and primary particle diameters from 10-400 nm;
natural silicates such as kaolin, and other naturally occurring hydrated silicas;
- glass fibres and glass fibre products (mats, strand) or glass microspheres:
Le A 33 468 - metal oxides such as zinc oxide, calcium oxide, magnesium oxide, aluminium oxide;
- metal carbonates such as magnesium carbonate, calcium carbonate, zinc carbonate;
- metal hydroxides, such as aluminium hydroxide or magnesium hydroxide for example;
- carbon blacks. The carbon blacks which are used here are produced by the flame black, furnace black or gas black processes and have BET specific surfaces from 20-200 m2/g, e.g. SAF, ISAF, HAF, FEF or GPF carbon blacks;
- rubber gels, particularly those based on polybutadiene, butadiene/styrene copolymers, butadiene/acrylonitrile copolymers and polychloroprene.
Microdispersed hydrated silicas and/or carbon blacks are preferably used as fillers.
The aforementioned fillers can be used on their own or in admixture. In one particular preferred embodiment, the rubber compounds contain, as fillers, a mixture of light fillers such as microdispersed hydrated silicas, and carbon blacks, wherein the mixture ratio of light fillers to carbon blacks ranges from 1:0.05 to 1:20, preferably from 1:0.1 to 1:10.
In addition to the aforementioned solution rubbers which contain aminoisoprenes, the rubber compounds according to the invention may also other rubbers, such as natural rubber and other synthetic rubbers also.
The preferred rubbers used for synthesis are described by W. Hofmann, Kautschuk-technologie, Gentner Verlag, Stuttgart 1980, and by I. Franta, Elastomers and Rubber Compounding Materials, Elsevier, Amsterdam 1989, for example. Amongst other substances, they comprise LeA33468 _g_ BR - polybutadiene ABRs - butadiene/acrylic acid C,~ alkyl ester copolymers CR polychloroprene IR - polyisoprene SBRs - styrene/butadiene copolymers with styrene contents from 1 to 60, preferably from 20 to 50 % by weight IIRs - isobutylene/isoprene copolymers NBRs - butadiene/acrylonitrile copolymers with acrylonitrile contents from 5 to l0 60, preferably from 10 to 40 % by weight HNBR - partially hydrogenated or completely hydrogenated NBR rubber EPDM - ethylene/propylene/diene copolymers as well as mixtures of these rubbers. Rubbers which are particularly suitable for the production of motor vehicle tyres, and which contain surface-modified fillers, include natural rubber, emulsion SBR rubbers and solution SBR rubbers with a glass transition temperature above -50°C, which may optionally be modified with silyl ethers or other functional groups according to EP-A 447 066, polybutadiene rubber with a high 1,4-cis content (>90 %) which has been produced using catalysts based on Ni, Co, Ti or Nd, and polybutadiene rubber with a vinyl content of up to 75 %, as well as mixtures thereof which are of interest.
As mentioned above, additional rubbers can also be admixed with the rubber compounds according to the invention, in addition to the solution rubber which contains aminoisoprene. The amount of these additional rubbers usually falls within the range from 0.5 to 70, preferably from 10 to 50 % by weight with respect to the total amount of rubber in the rubber compound. The amount of rubbers which are additionally added again depends on the respective purpose of use of the rubber compounds according to the invention.
The rubber compounds according to the invention may also of course contain other rubber adjuvant substances, which may be employed for crosslinking vulcanised Le A 33 468 products which are produced from the rubber compounds, for example, or which improve the physical properties of vulcanised products produced from the rubber compounds according to the invention for the specific purpose of use thereof.
Examples of crosslinking agents which can be used include sulphur or compounds which provide sulphur, or crosslinking agents which supply radicals, such as organic peroxides for example. Sulphur is preferably used as a crosslinking agent. In addition, and as mentioned above, the rubber compounds according to the invention may contain other adjuvant substances such as known reaction accelerators, anti-ageing IO agents, thermal stabilisers, light stabilisers, ozone stabilisers, processing aids, plasticisers, tackifiers, foaming agents, colorants, pigments, waxes, extenders, organic acids, retardants and metal oxides, as well as activators.
The rubber adjuvant substances according to the invention are used in the known customary amounts, the amount used depending on the subsequent purpose of use of the rubber compounds. The customary amounts of rubber adjuvant substances fall within the range from 2 to 70 parts by weight with respect to 100 parts by weight of the total amount of rubber which is present, for example.
The use of additional filler activators is particularly advantageous for the rubber compounds according to the invention, which are filled with highly active hydrated silicas. The preferred filler activators are silyl ethers which contain sulphur, particularly bis-(trialkoxisilylalkyl) polysulphides such as those described in DE 2 141 159 and DE 2 255 577. Other suitable filler activators which can be used include mercapatoalkyltrialkoxysilanes, particularly mercaptopropyltriethoxysilane and thiocyanatoalkylsilyl ethers (see DE 19 544 469). The filler activators are used in the customary amounts, i.e. in amounts from 0.1 to 15 parts by weight with respect to 100 parts by weight of the total amount of rubber.
The rubber compounds according to the invention can be produced, for example, by mixing the aminoisoprene-containing solution rubbers, and optionally other rubbers, Le A 33 468 with the corresponding fillers and rubber adjuvant substances in suitable mixing apparatuses such as kneaders, rolls, or extruders.
The present invention further relates to the use of the rubber compounds according to the invention for the production of vulcanised products, which in turn are employed for the production of highly reinforced rubber mouldings, particularly for the production of tyres.
Le A 33 468 Examines Example 1:
S A solution of 120.1 g ( 1.15 mol) styrene, 175.0 g (3.24 mol) butadiene and 4.93 g (0.044 mot) 5-(N;N-dimethylamino)-isoprene in 2300 ml of dry hexane were placed in a stirred autoclave. 1.54 ml of a 1.3 molar solution of sec-butyllithium in cyclohexane/hexane were added thereto at 35°C. The reaction was exothermic and was restricted by cooling the batch to 60°C. After 1.5 hours, polymerisation was stopped by adding 0.1 ml methanol. The polymer was subsequently precipitated in 14 litres of methanol and dried.
The dimethylaminoisoprene SBR rubber which was thus obtained had an average (number average) molecular weight of 120,000 and a styrene content of 36 % by weight. The butadiene content was 62.4 % by weight, with a 1,2-vinyl content of 16 (with respect to the total polymer). The content of diaminoisoprene incorporated by polymerisation was 1.6 % by weight. The glass transition temperature was -33°C, and the viscosity ML 1+4 (100°C) was 20.
Examule 2:
A solution of 116.1 g ( 1.12 mol) styrene, 160.0 g (2.96 mol) butadiene and 23.8 g (0.215 mol) 5-(N,N-dimethylamino)-isoprene in 2300 ml of dry hexane were placed in a stirred autoclave. 1.54 ml of a 1.3 molar solution of sec-butyllithium in cyclohexane/hexane were added thereto at 35°C. The reaction was exothermic and was restricted by cooling the batch to 60°C. After 1.5 hours, polymerisation was stopped by adding 0.1 ml methanol. The polymer was subsequently precipitated in 14 litres of methanol and dried.
The dimethylaminoisoprene SBR rubber which was thus obtained had an average (number average) molecular weight of 120,000 and a styrene content of 36 % by weight. The butadiene content was 56 % by weight, with a 1,2-vinyl content of Le A 33 468 * (with respect to the total polymer). The content of diaminoisoprene incorporated by polymerisation was 8 % by weight. The glass transition temperature was -48°C.
Egamule 3:
'The following rubber compounds were produced at 130°C in a 1.5 litre kneader.
Finally, were sulphur and an accelerator were admixed on a roll at 50°C.
Le A 33 468 Comparative example Example according to the invention Mixed in the kneader:
$ Buna VSL 2035-0 solution SBR (Bayer75 0 AG) rubber according to Example 1 0 75 Buna CB 11 polybutadiene rubber 25 25 (Bayer AG) Vulkasil S precipitated hydrated 80 80 silica(Bayer AG) Corax N 339 carbon black (Degussa) 6.5 6.5 Renopal 450 aromatic plasticiser 32.5 32.5 zinc oxide 2.5 2.5 stearic acid 1 1 Vulkanox 4020 antioxidant (Bayer 1 1 AG) 1654 ozone-protective wax (Rheinchemie)1.5 1.5 1$ Si 69 silane (Degussa) 3.5 3.5 admixed on the roll (50C):
sulphur 1.5 1.5 Vulkacit CZ N-cyclohexyl-mercaptobenzthiazole1.5 1.5 sulphenamide Vulkacit D diphenylguanidine (Bayer2 2 AG) Mooney viscosity ML I+4 (100°C) 106 106 vulcanisation kinetics at 160°C:
time to reach 6 % of the final torque value (minutes) 2.3 2.1 2$ time to reach 90 % of the final torque value (minutes) I 5.2 14.2 The rubber compounds were subsequently vulcanised at 160°C. The vulcanised products had the following properties:
3~ stress value at 300 % elongation8.8 12.9 (MPa) tensile strength (MPa) 17.4 19.9 elongation at break (%) 520 459 hardness at 23C (Shore A) 75 79 rebound resilience at 30C (%) 39 45 3$ abrasion according to DIN 101 85 53 516 (ccm)
Rubber comyounds based on aminoisoprene nolymers and the use thereof for the uroduction of tyre treads which exhibit a low rolling resistance The present invention relates to rubber compounds based on homo- and copolymers of special aminoisoprenes and fillers, and relates to vulcanised products thereof. The rubber compounds according to the invention or the vulcanised products thereof are suitable for the production of highly reinforced, abrasion-resistant mouldings, particularly for the production of tyres which exhibit a low rolling resistance and a high abrasion-resistance.
Compared with corresponding emulsion rubbers, anionically polymerised solution rubbers which contain double bonds, such as solution polybutadiene and solution styrene/butadiene rubbers, exhibit advantages for the production of tyre treads which exhibit a low rolling resistance. Amongst others, these advantages are the facility of controlling the vinyl content and the glass transition temperature which is associated therewith, and of controlling the extent of molecular branching. In practical application, this results in particular advantages in the relationship between the wet-slip resistance and the rolling resistance of the tyres. Thus US-PS 5 227 425 describes the production of tyre treads from a solution SBR rubber and hydrated silica.
In order to achieve a further improvement in properties, numerous methods have been developed for modifying the terminal groups, such as that which employs dimethylaminopropyl-acrylamide and which is described in EP-A 334 042, or such as that which employs silyl ethers and which is described EP-A 447 066. However, due to the high molecular weight of rubbers, the proportion by weight of terminal groups is low, and is therefore only capable of exerting a slight effect on the interaction between a filler and a rubber molecule. The object of the present invention was therefore to produce solution rubbers having a considerably higher content of amino groups.
US-PS 3 544 532 describes cationically unsaturated polymers, for the production of which polymers of 2-dialkylaminomethyl-1,3-butadiene are used, amongst other LeA33468 substances. These polymers are produced by emulsion polymerisation or by subsequent reactions analogous to polymerisation, and therefore have a microstructure (1,2-vinyl content, long-chain branching, molecular weight distribution, distribution of the copolymer in the monomer) which differs from that of the anionically initiated solution polymers of the present invention. The aforementioned US Patent does not mention of the use of these rubbers for tyres.
Emulsion rubbers which are produced from dimes and vinyl monomers which contain amino groups, and the use thereof in tyre treads filled with hydrated silica, are known from EP 819 731. However, due to the production of these rubbers under conditions of radical-initiated polymerisation, the known advantages of anionically polymerised solution rubbers cannot be achieved, as mentioned above. lvloreover, the monomers used there are structurally different from the dialkylaminoisoprene monomers of the present invention.
The object of the present invention was therefore to provide compounds comprising rubbers which contain amino groups, from which tyres can be produced which exhibit improved wet slip-resistance as well as high mechanical strength and improved abrasion behaviour.
The present invention therefore relates to rubber compounds consisting of a rubber and 10 to 500 parts by weight, preferably 20 to 200 parts by weight, of a filler with respect to 100 parts by weight rubber, wherein the rubber has been produced by polymerisation in solution and has a content of aminoisoprenes, which are incorporated by polymerisation, of formula Rz R~-N
wherein Le A 33 468 RI and RZ, independently of each other, represent CI-C~8 alkyl- or CS-C12 cycloalkyl radicals, which can optionally be interrupted by one or more 'nitrogen, oxygen and/or sulphur atoms or which jointly form a ring, and also represent C6-Cg aryl- or C~-C24 alkylaryl radicals, from 0.01 to 100 % by weight, preferably 0.1 to 10 % by weight, a content of diolefines from 0 to 99.99 % by weight, preferably 55 to 99.9 % by weight, and a content of aromatic vinyl monomers, incorporated by polymerisation, from 0 to by weight, preferably 0 to 45 % by weight, with respect to the solution rubber in each case, and has a (number average) molecular weight from 10,000 to 2,000,000 and in addition has a glass transition temperature from -100°C to +20°C.
Aminoisoprenes which are suitable for polymerisation and which are particularly preferred have the following structures:
~Hs NCH ~zHs ~~Hs N a N~..CzHs N,-CHs a) b) c) n-C H CaH~ pz~"~zs N~n~CaH~ ~~j_Ca~r N--CH3 ) ~O /--NCH3 ~NCzHs N~ N~~ N
g) h) i) ' CA 02361965 2001-08-O1 Le A 33 468 CHs N N~O~C~
.1) k) 1) H
N
m) n) Examples of aromatic vinyl monomers which can be used for polymerisation include styrene, o-, m- and p-methylstyrene, p-tert.-butylstyrene, a-methylstyrene, vinylnaphthalene, divinylbenzene, trivinylbenzene and/or divinylnaphthalene.
Styrene is most preferably used.
Diolefines which can be used for polymerisation according to the invention include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 1-vinyl-1,3-butadiene and/or 1,3 -hexadiene. 1,3-butadiene and isoprene are most preferably used.
The rubbers based on aminoisoprene monomers and optionally other diolefines and aromatic vinyl monomers which can be used according to the invention preferably have average (number average) molecular weights from 100,000 to 1,000,000, glass transition temperatures which preferably range from -40°C to 0°C, and Mooney viscosities ML 1+4 (100°C) from 10 to 200, preferably from 30 to 150.
Le A 33 468 The aminoisoprenes can be produced by methods known in the art: for example from 2-chloromethyl-1,.3-butadiene and secondary amines as described in US
3,544,532, or from secondary amines, formaldehyde, allyl alcohol, dimethyl sulphoxide and potassium-tert.-butylate as described in Angew. Chem. 102 (1990) 929. The structure of the secondary amines which can be used can be varied within wide limits.
The aminoisoprene-based rubbers according to the invention are produced by anionic solution polymerisation. i.e. by means of a catalyst based on alkali metals, preferably in an inert hydrocarbon as a solvent. The known randomising agents and control agents for the microstructure of the polymer can be used in addition. Anionic solution polymerisation methods of this type are known, and are described, for example, by I.
Franta in Elastomers and Rubber Compounding Materials; Elsevier 1989. pages 73-74. 92-94 and in Houben-Weyl, Methoden der Organischen Chemie, Thieme Verlag, Stuttgart, 1987, Volume E 20, pages 114 - 134.
Examples of suitable alkali metal catalysts include lithium, sodium, potassium, rubidium, and caesium metals and hydrocarbon compounds thereof, as well as com-plex compounds thereof with polar organic compounds.
Lithium and sodium hydrocarbon compounds comprising 2 to 20 carbon atoms are particularly preferred, for example ethyllithium, n-propyllithium, i-propyllithium, n-butyllithium, sec-butyllithium, tetr.-octyllithium, n-decyllithium, phenyllithium, 2-naphthyllithium, 2-butylphenyllithium, cyclohexyllithium, 4-cyclopentyllithium, 1,4-dilithiobutene-2, sodium naphthalene, sodium biphenyl, potassium tetrahydrofuran complex, potassium diethoxyethane complex, and sodium tetramethylethylene-diamine complex. These catalysts can be use on their own or in admixture.
The amounts of catalyst range from 0.1 to 10 mmol /100 g polymer, preferably from 0.5 to 5 mmol/100 g polymer.
Anionic solution polymerisation is preferably conducted in a hydrocarbon, but can also be conducted in another solvent which does not destroy the catalyst, for example Le A 33 468 in tetrahydrofuran, tetrahydropyran or 1,4-dioxane. Example of hydrocarbons which are suitable as solvents include aliphatic, cycloaliphatic or aromatic hydrocarbons comprising 2 to 12 carbon atoms. The preferred solvents are propane, butane, pentane, hexane, cyclohexane, propene, butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, benzene, toluene and xylene. The solvents can be used on their own or in admixture.
The appropriate amount of solvent can easily be determined by preliminary tests.
The polymers, which can be produced by anionic solution polymerisation, can also be "coupled" by known methods, for example by means of disulphur dichloride or by the reaction of the live polymer anion with silicon tetrachloride.
Suitable fillers for the rubber compounds according to the invention include all fillers which are known and used in the rubber industry, comprising both active and inactive fillers.
Examples thereof include:
- microdispersed hydrated silicas, for example those produced by precipitation from solution of silicates or by the flame hydrolysis of silicon halides having specific surfaces from 5 - 1000, preferably 20-400 m2/g (BET specific surface) and having primary particle sizes from 10-400 nm. The hydrated silicas may optionally also exist as mixed oxides with other metal oxides such as AI, Mg, Ca, Ba, Zn, Zr or Ti oxides;
- synthetic silicates such as aluminium silicate, or alkaline earth silicates such as magnesium silicate or calcium silicate, which have BET specific surfaces from 20-400 m2/g and primary particle diameters from 10-400 nm;
natural silicates such as kaolin, and other naturally occurring hydrated silicas;
- glass fibres and glass fibre products (mats, strand) or glass microspheres:
Le A 33 468 - metal oxides such as zinc oxide, calcium oxide, magnesium oxide, aluminium oxide;
- metal carbonates such as magnesium carbonate, calcium carbonate, zinc carbonate;
- metal hydroxides, such as aluminium hydroxide or magnesium hydroxide for example;
- carbon blacks. The carbon blacks which are used here are produced by the flame black, furnace black or gas black processes and have BET specific surfaces from 20-200 m2/g, e.g. SAF, ISAF, HAF, FEF or GPF carbon blacks;
- rubber gels, particularly those based on polybutadiene, butadiene/styrene copolymers, butadiene/acrylonitrile copolymers and polychloroprene.
Microdispersed hydrated silicas and/or carbon blacks are preferably used as fillers.
The aforementioned fillers can be used on their own or in admixture. In one particular preferred embodiment, the rubber compounds contain, as fillers, a mixture of light fillers such as microdispersed hydrated silicas, and carbon blacks, wherein the mixture ratio of light fillers to carbon blacks ranges from 1:0.05 to 1:20, preferably from 1:0.1 to 1:10.
In addition to the aforementioned solution rubbers which contain aminoisoprenes, the rubber compounds according to the invention may also other rubbers, such as natural rubber and other synthetic rubbers also.
The preferred rubbers used for synthesis are described by W. Hofmann, Kautschuk-technologie, Gentner Verlag, Stuttgart 1980, and by I. Franta, Elastomers and Rubber Compounding Materials, Elsevier, Amsterdam 1989, for example. Amongst other substances, they comprise LeA33468 _g_ BR - polybutadiene ABRs - butadiene/acrylic acid C,~ alkyl ester copolymers CR polychloroprene IR - polyisoprene SBRs - styrene/butadiene copolymers with styrene contents from 1 to 60, preferably from 20 to 50 % by weight IIRs - isobutylene/isoprene copolymers NBRs - butadiene/acrylonitrile copolymers with acrylonitrile contents from 5 to l0 60, preferably from 10 to 40 % by weight HNBR - partially hydrogenated or completely hydrogenated NBR rubber EPDM - ethylene/propylene/diene copolymers as well as mixtures of these rubbers. Rubbers which are particularly suitable for the production of motor vehicle tyres, and which contain surface-modified fillers, include natural rubber, emulsion SBR rubbers and solution SBR rubbers with a glass transition temperature above -50°C, which may optionally be modified with silyl ethers or other functional groups according to EP-A 447 066, polybutadiene rubber with a high 1,4-cis content (>90 %) which has been produced using catalysts based on Ni, Co, Ti or Nd, and polybutadiene rubber with a vinyl content of up to 75 %, as well as mixtures thereof which are of interest.
As mentioned above, additional rubbers can also be admixed with the rubber compounds according to the invention, in addition to the solution rubber which contains aminoisoprene. The amount of these additional rubbers usually falls within the range from 0.5 to 70, preferably from 10 to 50 % by weight with respect to the total amount of rubber in the rubber compound. The amount of rubbers which are additionally added again depends on the respective purpose of use of the rubber compounds according to the invention.
The rubber compounds according to the invention may also of course contain other rubber adjuvant substances, which may be employed for crosslinking vulcanised Le A 33 468 products which are produced from the rubber compounds, for example, or which improve the physical properties of vulcanised products produced from the rubber compounds according to the invention for the specific purpose of use thereof.
Examples of crosslinking agents which can be used include sulphur or compounds which provide sulphur, or crosslinking agents which supply radicals, such as organic peroxides for example. Sulphur is preferably used as a crosslinking agent. In addition, and as mentioned above, the rubber compounds according to the invention may contain other adjuvant substances such as known reaction accelerators, anti-ageing IO agents, thermal stabilisers, light stabilisers, ozone stabilisers, processing aids, plasticisers, tackifiers, foaming agents, colorants, pigments, waxes, extenders, organic acids, retardants and metal oxides, as well as activators.
The rubber adjuvant substances according to the invention are used in the known customary amounts, the amount used depending on the subsequent purpose of use of the rubber compounds. The customary amounts of rubber adjuvant substances fall within the range from 2 to 70 parts by weight with respect to 100 parts by weight of the total amount of rubber which is present, for example.
The use of additional filler activators is particularly advantageous for the rubber compounds according to the invention, which are filled with highly active hydrated silicas. The preferred filler activators are silyl ethers which contain sulphur, particularly bis-(trialkoxisilylalkyl) polysulphides such as those described in DE 2 141 159 and DE 2 255 577. Other suitable filler activators which can be used include mercapatoalkyltrialkoxysilanes, particularly mercaptopropyltriethoxysilane and thiocyanatoalkylsilyl ethers (see DE 19 544 469). The filler activators are used in the customary amounts, i.e. in amounts from 0.1 to 15 parts by weight with respect to 100 parts by weight of the total amount of rubber.
The rubber compounds according to the invention can be produced, for example, by mixing the aminoisoprene-containing solution rubbers, and optionally other rubbers, Le A 33 468 with the corresponding fillers and rubber adjuvant substances in suitable mixing apparatuses such as kneaders, rolls, or extruders.
The present invention further relates to the use of the rubber compounds according to the invention for the production of vulcanised products, which in turn are employed for the production of highly reinforced rubber mouldings, particularly for the production of tyres.
Le A 33 468 Examines Example 1:
S A solution of 120.1 g ( 1.15 mol) styrene, 175.0 g (3.24 mol) butadiene and 4.93 g (0.044 mot) 5-(N;N-dimethylamino)-isoprene in 2300 ml of dry hexane were placed in a stirred autoclave. 1.54 ml of a 1.3 molar solution of sec-butyllithium in cyclohexane/hexane were added thereto at 35°C. The reaction was exothermic and was restricted by cooling the batch to 60°C. After 1.5 hours, polymerisation was stopped by adding 0.1 ml methanol. The polymer was subsequently precipitated in 14 litres of methanol and dried.
The dimethylaminoisoprene SBR rubber which was thus obtained had an average (number average) molecular weight of 120,000 and a styrene content of 36 % by weight. The butadiene content was 62.4 % by weight, with a 1,2-vinyl content of 16 (with respect to the total polymer). The content of diaminoisoprene incorporated by polymerisation was 1.6 % by weight. The glass transition temperature was -33°C, and the viscosity ML 1+4 (100°C) was 20.
Examule 2:
A solution of 116.1 g ( 1.12 mol) styrene, 160.0 g (2.96 mol) butadiene and 23.8 g (0.215 mol) 5-(N,N-dimethylamino)-isoprene in 2300 ml of dry hexane were placed in a stirred autoclave. 1.54 ml of a 1.3 molar solution of sec-butyllithium in cyclohexane/hexane were added thereto at 35°C. The reaction was exothermic and was restricted by cooling the batch to 60°C. After 1.5 hours, polymerisation was stopped by adding 0.1 ml methanol. The polymer was subsequently precipitated in 14 litres of methanol and dried.
The dimethylaminoisoprene SBR rubber which was thus obtained had an average (number average) molecular weight of 120,000 and a styrene content of 36 % by weight. The butadiene content was 56 % by weight, with a 1,2-vinyl content of Le A 33 468 * (with respect to the total polymer). The content of diaminoisoprene incorporated by polymerisation was 8 % by weight. The glass transition temperature was -48°C.
Egamule 3:
'The following rubber compounds were produced at 130°C in a 1.5 litre kneader.
Finally, were sulphur and an accelerator were admixed on a roll at 50°C.
Le A 33 468 Comparative example Example according to the invention Mixed in the kneader:
$ Buna VSL 2035-0 solution SBR (Bayer75 0 AG) rubber according to Example 1 0 75 Buna CB 11 polybutadiene rubber 25 25 (Bayer AG) Vulkasil S precipitated hydrated 80 80 silica(Bayer AG) Corax N 339 carbon black (Degussa) 6.5 6.5 Renopal 450 aromatic plasticiser 32.5 32.5 zinc oxide 2.5 2.5 stearic acid 1 1 Vulkanox 4020 antioxidant (Bayer 1 1 AG) 1654 ozone-protective wax (Rheinchemie)1.5 1.5 1$ Si 69 silane (Degussa) 3.5 3.5 admixed on the roll (50C):
sulphur 1.5 1.5 Vulkacit CZ N-cyclohexyl-mercaptobenzthiazole1.5 1.5 sulphenamide Vulkacit D diphenylguanidine (Bayer2 2 AG) Mooney viscosity ML I+4 (100°C) 106 106 vulcanisation kinetics at 160°C:
time to reach 6 % of the final torque value (minutes) 2.3 2.1 2$ time to reach 90 % of the final torque value (minutes) I 5.2 14.2 The rubber compounds were subsequently vulcanised at 160°C. The vulcanised products had the following properties:
3~ stress value at 300 % elongation8.8 12.9 (MPa) tensile strength (MPa) 17.4 19.9 elongation at break (%) 520 459 hardness at 23C (Shore A) 75 79 rebound resilience at 30C (%) 39 45 3$ abrasion according to DIN 101 85 53 516 (ccm)
Claims (5)
1. Rubber compounds consisting of a rubber and 10 to 500 parts by weight of a filler with respect to 100 parts by weight rubber, wherein the rubber has been produced by polymerisation in solution and has a content of aminoisoprenes, which are incorporated by polymerisation, of formula wherein R1 and R2, independently of each other, represent C1-C18 alkyl- or C5-C12 cycloalkyl radicals, which can optionally be interrupted by one or more nitrogen, oxygen and/or sulphur atoms or which jointly form a ring, and also represent C6-C8 aryl- or C7-C24 alkylaryl radicals, from 0.01 to 100 % by weight, a content of diolefines from 0 to 99.99 % by weight, and a content of aromatic vinyl monomers, incorporated by polymerisation, from 0 to 50 % by weight, with respect to the solution rubber in each case, and has a (number average) molecular weight from 10,000 to 2,000,000 and in addition has a glass transition temperature from -100°C to +20°C.
2. Rubber compounds according to claim 1, characterised in that the rubber compounds contain 20 to 200 parts by weight of a filler with respect to 100 parts by weight of rubber.
3. Rubber compounds according to claim 1, characterised in that the rubbers have a content of bound aminoisoprenes from 0.1 to 10 % by weight.
4. Rubber compounds according to claim 1, characterised in that in addition to the aminoisoprenes incorporated by polymerisation the rubbers a content of aromatic vinyl monomers, which are incorporated by polymerisation, from 0 to 45 % by weight and a content of other diolefines, which are incorporated by polymerisation, from 55 to 99.9 % by weight.
5. The use of the rubber compounds according to claim 1 for the production of rubber mouldings, particularly for the production of tyres.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19904357 | 1999-02-03 | ||
| DE19904357.4 | 1999-02-03 | ||
| PCT/EP2000/000786 WO2000046263A1 (en) | 1999-02-03 | 2000-02-01 | Rubber mixtures based on amino-isoprene polymers and their use in the production of tire treads with low rolling resistance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2361965A1 true CA2361965A1 (en) | 2000-08-10 |
Family
ID=7896308
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002361965A Abandoned CA2361965A1 (en) | 1999-02-03 | 2000-02-01 | Rubber mixtures based on amino-isoprene polymers and their use in the production of tire treads with low rolling resistance |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP1165641B1 (en) |
| JP (1) | JP2002536472A (en) |
| KR (1) | KR20010093318A (en) |
| AU (1) | AU2668500A (en) |
| BR (1) | BR0007928A (en) |
| CA (1) | CA2361965A1 (en) |
| DE (1) | DE50001973D1 (en) |
| ES (1) | ES2193051T3 (en) |
| WO (1) | WO2000046263A1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU2001279824A1 (en) * | 2000-09-08 | 2002-03-22 | Bayer Aktiengesellschaft | Quaternary polymers with functional amine groups |
| EP1400543B1 (en) * | 2002-09-19 | 2009-11-11 | The Goodyear Tire & Rubber Company | Functionalized elastomers |
| JP5864903B2 (en) * | 2011-05-20 | 2016-02-17 | 株式会社ブリヂストン | Rubber composition |
| FR3059331A1 (en) * | 2016-11-28 | 2018-06-01 | Compagnie Generale Des Etablissements Michelin | TIRE TREAD FOR TIRES |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3622799B2 (en) * | 1995-09-05 | 2005-02-23 | 日本ゼオン株式会社 | Rubber composition |
-
2000
- 2000-02-01 WO PCT/EP2000/000786 patent/WO2000046263A1/en not_active Application Discontinuation
- 2000-02-01 DE DE50001973T patent/DE50001973D1/en not_active Expired - Fee Related
- 2000-02-01 BR BR0007928-6A patent/BR0007928A/en not_active Withdrawn
- 2000-02-01 AU AU26685/00A patent/AU2668500A/en not_active Abandoned
- 2000-02-01 EP EP00904998A patent/EP1165641B1/en not_active Expired - Lifetime
- 2000-02-01 JP JP2000597333A patent/JP2002536472A/en active Pending
- 2000-02-01 CA CA002361965A patent/CA2361965A1/en not_active Abandoned
- 2000-02-01 KR KR1020017009741A patent/KR20010093318A/en not_active Application Discontinuation
- 2000-02-01 ES ES00904998T patent/ES2193051T3/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| AU2668500A (en) | 2000-08-25 |
| EP1165641B1 (en) | 2003-05-02 |
| EP1165641A1 (en) | 2002-01-02 |
| JP2002536472A (en) | 2002-10-29 |
| WO2000046263A1 (en) | 2000-08-10 |
| KR20010093318A (en) | 2001-10-27 |
| BR0007928A (en) | 2001-11-06 |
| ES2193051T3 (en) | 2003-11-01 |
| DE50001973D1 (en) | 2003-06-05 |
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