CA2326305A1 - Rubber mixtures of diene rubbers containing hydroxyl and carboxyl groups and sulfur-free crosslinking agents - Google Patents
Rubber mixtures of diene rubbers containing hydroxyl and carboxyl groups and sulfur-free crosslinking agents Download PDFInfo
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- CA2326305A1 CA2326305A1 CA002326305A CA2326305A CA2326305A1 CA 2326305 A1 CA2326305 A1 CA 2326305A1 CA 002326305 A CA002326305 A CA 002326305A CA 2326305 A CA2326305 A CA 2326305A CA 2326305 A1 CA2326305 A1 CA 2326305A1
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- rubber
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- carboxyl groups
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
- B60C1/0016—Compositions of the tread
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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
- C08L9/06—Copolymers with styrene
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08C—TREATMENT OR CHEMICAL MODIFICATION OF RUBBERS
- C08C19/00—Chemical modification of rubber
- C08C19/30—Addition of a reagent which reacts with a hetero atom or a group containing hetero atoms of the macromolecule
- C08C19/34—Addition of a reagent which reacts with a hetero atom or a group containing hetero atoms of the macromolecule reacting with oxygen or oxygen-containing groups
- C08C19/36—Addition of a reagent which reacts with a hetero atom or a group containing hetero atoms of the macromolecule reacting with oxygen or oxygen-containing groups with carboxy radicals
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08C—TREATMENT OR CHEMICAL MODIFICATION OF RUBBERS
- C08C19/00—Chemical modification of rubber
- C08C19/30—Addition of a reagent which reacts with a hetero atom or a group containing hetero atoms of the macromolecule
- C08C19/34—Addition of a reagent which reacts with a hetero atom or a group containing hetero atoms of the macromolecule reacting with oxygen or oxygen-containing groups
- C08C19/38—Addition of a reagent which reacts with a hetero atom or a group containing hetero atoms of the macromolecule reacting with oxygen or oxygen-containing groups with hydroxy radicals
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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
- C08L15/00—Compositions of rubber derivatives
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L19/00—Compositions of rubbers not provided for in groups C08L7/00 - C08L17/00
- C08L19/006—Rubber characterised by functional groups, e.g. telechelic diene polymers
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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
Abstract
The present invention relates to rubber mixtures comprising at least one rubber and to 800 parts by wt. of filler, based on 100 parts by wt. of rubber, wherein the rubber has been prepared by polymerization of diolefins and optionally further vinylaromatic monomers and introduction of hydroxyl and/or carboxyl groups, this rubber has a total content of 0.05 to 5 wt.% of bonded hydroxyl and/or carboxyl groups or salts thereof, and has a content of polymerized-in vinylaromatic monomers of 0 to 50 wt.% and a content of diolefins of 45 to 99.95 wt.%, the content of 1,2-bonded diolefins (vinyl content) being 0 to 80 wt.%, and 0.001 to 40 parts by wt. of a compound which is capable of crosslinking the rubber with the hydroxyl or carboxyl groups of the rubber, and optionally further rubbers, rubber auxiliaries and crosslinking agents.
The rubber mixtures according to the invention and vulcanization products thereof are suitable for the production of highly reinforced shaped rubber articles, in particular tyres, which have a particularly high resistance to thermal and mechanical stresses, a high wet skidding resistance, low rolling resistance and high abrasion resistance.
The rubber mixtures according to the invention and vulcanization products thereof are suitable for the production of highly reinforced shaped rubber articles, in particular tyres, which have a particularly high resistance to thermal and mechanical stresses, a high wet skidding resistance, low rolling resistance and high abrasion resistance.
Description
Le A 34 080-Foreign Countries Bg/ngb/NT
Rubber mixtures of dime rubbers containing hydroxyl and carboxyl ~rouns and sulfur-free crosslinkin~ agents . The present invention relates to rubber mixtures of dime rubbers containing hydroxyl and/or carboxyl groups, fillers and sulfur-free crosslinking agents which can crosslink the rubber via the hydroxyl or carboxyl groups, and the use thereof for the preparation of rubber vulcanization products with improved dynamic damping, improved mechanical strength, reversion resistance and adhesion to strength supports. The rubber mixtures and vulcanization products are suitable for the production of highly reinforced shaped rubber articles, in particular tyres, which have a particularly high resistance to thermal and mechanical stresses, a high wet skidding resistance, low rolling resistance and high abrasion resistance.
Numerous routes have been investigated for the production of motor vehicle tyres with reduced rolling resistance, improved wet skidding resistance, lower abrasion and higher heat resistance. The use of anionically polymerized solution rubbers containing double bonds, such as solution polybutadiene and solution styrene/-butadiene rubbers, has proved to be particularly advantageous. The advantages lie, inter alia, in the controllability of the vinyl content and of the associated glass transition temperature, a favourable cis/trans double bond ratio and the molecular branching. When used in practice, particular advantages result from this in the ratio of wet skidding resistance and rolling resistance of the tyre. l1S-A 5 227 425 thus describes the production of tyre treads from a solution SBR rubber and silica.
Emulsion and solution rubbers containing hydroxyl groups are described e.g. in EP-A 806 452, but here the rubbers are not crosslinked via the hydroxyl groups but are vulcanized in the conventional manner by crosslinking with sulfur. Due to the process, the hydroxyl contents described there for solution rubbers are in a particularly lower range (0.009 to 0.061%) and are therefore too low for effective crosslinking.
Le A 34 080-Foreign Countries A process for the preparation of solution polybutadiene rubbers containing hydroxyl and/or carboxyl groups (3.9 to 8.9 wt.%) is described, inter alia, in DE-A 2 653 144.
These rubbers are also crosslinked exclusively with sulfur, and because their strength is too low and their moduli are too low, they are not suitable as the main component in tyres.
A process for the preparation of solution rubbers containing hydroxyl groups by reaction of rubbers with particular long-chain hydroxylmercaptans is also described in EP-A 464 478. No references are given to the preparation of rubber mixtures with sulfur-free crosslinking agents which react with the hydroxyl groups and to corresponding vulcanization products.
Unsaturated rubbers which have been grafted with metal salts of unsaturated carboxylic acids are described in US-A S 962 593. Here also, crosslinking of the rubbers takes place by sulfur vulcanization. Furthermore, the content of carboxylic acid groups is considerably higher.
German Patent Applications no. 198 32 459.6, 198 52 648.2, 199 14 848.1, 199 20 788.7 and 199 20 894.8 describe solution rubbers containing hydroxyl and/or carboxyl groups with an advantageous content (0.1 to 3 wt.%) of hydroxyl and/or carboxyl groups. However, the patent applications give no indication of improved crosslinking systems which react with the functional groups.
The object of the present invention was therefore to provide mixtures of rubbers, particularly preferably solution rubbers, containing hydroxyl and/or carboxyl groups and specific crosslinking agents which react chemically with the hydroxyl or carboxyl groups under vulcanization conditions, from which tyres with improved wet skidding resistance, lower rolling resistance, high mechanical and heat resistance and improved abrasion properties can be produced.
Le A 34 080-Foreign Countries The present invention therefore provides rubber mixtures comprising at least one rubber and 10 to 800 parts by wt. of filler, based on 100 parts by wt. of rubber, wherein the rubber has been prepared by polymerization of diolefins and optionally further vinylaromatic monomers and introduction of hydroxyl and/or carboxyl groups, this rubber has a total content of 0.05 to 5 wt.% of bonded hydroxyl and/or carboxyl groups or salts thereof, and has a content of polymerized-in vinylaromatic monomers of 0 to 50 wt.% and a content of diolefins of 45 to 99.95 wt.%, the content of 1,2-bonded diolefins (vinyl content) being 0 to 80 wt.%, and 0.001 to 40 parts by wt. of a compound which is capable of crosslinking the rubber with the hydroxyl or carboxyl groups of the rubber (so-called sulfur-free crosslinking agent), and optionally further rubbers, rubber auxiliaries and crosslinking agents.
Rubber mixtures according to the invention which are preferred are those in which the rubber constituent has a content of bonded hydroxyl and/or carboxyl groups or salts thereof of 0.1 to 3 wt.% in total, and has a content of polymerized-in vinylaromatic monomers of 0 to 40 wt.%, particularly preferably 10 to 40 wt.%, and a content of diolefins of 99.9 to 60 wt.%, the content of 1,2-bonded diolefins (vinyl content) being in the range from 5 to 55 wt.%, and which have a content of 0.1 to 20 parts by wt. of sulfur-free crosslinking agent of the abovementioned type.
The amount of fillers is preferably 20 to 200 parts by wt.
Diolefins which are used according to the invention for the polymerization are 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 particularly preferably employed.
Examples which may be mentioned of vinylaromatic monomers which can be employed for the polymerization are styrene, o-, m- and p-methylstyrene, p-tert-butylstyrene, a-methylstyrene, vinylnaphthalene, divinylbenzene, trivinylbenzene and/or divinylnaphthalene. Styrene is particularly preferably employed.
Le A 34 080-Foreign Countries The rubbers based on diolefins and optionally further vinylaromatic monomers which are to be employed according to the invention in the rubber mixtures have average molecular weights (number-average) of 50,000 to 2,000,000, preferably 100,000 to 1,000,000, and glass transition temperatures of -110°C to +20°C, preferably -100°C
to 0°C, and Mooney viscosities ML 1+4 (100°C) of 10 to 200, preferably 30 to 150.
In addition to the hydroxyl and carboxylic acid groups or salts thereof, the rubbers according to the invention can also have further known functional groups, such as carboxylic acid ester, carboxylic acid amide or sulfonic acid groups.
Solution rubbers containing hydroxyl and carboxyl groups are particularly preferred, in particular such as are described in the abovementioned German patent applications and in DE-A 2 653 144 and EP-A 464 478.
Possible sulfur-free crosslinking agents in the sense according to the invention are all the polyfunctional compounds which are capable of bringing about vulcanization of the rubber mixture, i.e. crosslinking to form covalent chemical bonds, exclusively via the hydroxyl or carboxyl groups. In this connection, the term "sulfur-free" is understood as meaning that the compounds contain no vulcanization-active sulfur-containing groups. Crosslinking agents which have sulfur-containing groups which are stable under the vulcanization conditions, such as e.g. sulfone or monothioether groups, can also be employed in the context according to the invention.
Suitable crosslinking agents in the context of the invention are, above all, polyisocyanates, polyuretdiones, blocked polyisocyanates and/or polyepoxides. Particularly preferred classes of crosslinking agents are:
(A) Polyisocyanates, such as e.g. hexamethylene-diisocyanate (HDI), isophorone-diisocyanate (IPDI), toluene-diisocyanate (TDI), 4,4'-diisocyanatodiphenyl-methane (MDI), 1,6-diisocyanato-2,2,4-trimethylhexane (IPDI), tris-(4-isocyanatophenyl)-methane, phosphoric acid tris-(4-isocyanato-phenyl ester), Le A 34 080-Foreign Countries thiophosphoric acid tris-(4-isocyanato-phenyl ester) and oligomerization products thereof which have been obtained by reaction of the low molecular weight diisocyanates mentioned with diols or polyalcohols, in particular ethylene glycol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane or penta-erythritol, and have a residual content of free isocyanate groups, furthermore oligomerization products which have been obtained by reaction of the low molecular weight diisocyanates mentioned with polyesters containing hydroxyl groups, such as e.g. polyesters based on adipic acid and butanediol and hexanediol and having molecular weights of between 400 and 3,000, or by reaction with polyethers containing hydroxyl groups, such as polyethylene glycols or polypropylene glycols, or polytetrahydrofurans with molecular weights of 150 to 3,000 and have a residual content of free isocyanate groups, furthermore oligomerization products which have been obtained by reaction of the low molecular weight diisocyanates mentioned with amines or 1 S polyamines, in particular ammonia, diaminobutane or diaminohexane, and have a residual content of free isocyanate groups, or oligomerization products which have been obtained by reaction of the low molecular weight diisocyanates mentioned with water or by dimerization or trimerization, such as e.g. dimerized toluene-diisocyanate (Desmodur TT) and trimerized toluene-diisocyanate, or aliphatic uretdiones and polyuretdiones containing isocyanate groups, e.g. based on isophorone-diisocyanate, and have a residual content of free isocyanate groups. Preferred contents of free isocyanate groups are in the range from 2.5 to 25 wt.%. Such polyisocyanates are known and are commercially obtainable, in this context see Houben-Weyl, Methoden der Organischen Chemie [Methods of Organic Chemistry], volume XIV, pages 56-98, Georg Thieme Verlag Stuttgart 1963, and the commercial products of the Desmodur and Crelan series (Bayer AG);
Le A 34 080-Foreign Countries (B) Blocked polyisocyanates which react with the hydroxyl and/or carboxyl groups of the rubber under the vulcanization conditions. These include all the polyisocyanates mentioned under (A), the isocyanate groups in each case being blocked with suitable splitting-off groups which split off again at a higher temperature and thereby liberate the isocyanate groups. Suitable splitting-off groups are, in particular, caprolactam, malonic acid esters, phenol and alkylphenols, such as e.g. nonylphenol, as well as imidazole and sodium hydrogen sulfite. Polyisocyanates blocked with caprolactam, malonic esters and alkylphenol, in particular those based on toluene-diisocyanate or trimerized toluene-diisocyanate and isophorone-diisocyanate, are particularly preferred. Preferred blocked polyisocyanates are also obtained by dimerization of the isocyanate groups to uretdiones and polyuretdiones.
Preferred contents of blocked isocyanate groups are in the range from 2.5 to wt.%. Such blocked polyisocyanates are known and are commercially 15 obtainable, in this context see Houben-Weyl, Methoden der Organischen Chemie [Methods of Organic Chemistry], volume XIV, pages 56-98, Georg Thieme Verlag Stuttgart 1963, and the commercial products of the Desmodur and Crelan series (Bayer AG);
20 (C) Polyepoxides which react with the hydroxyl or carboxyl groups of the rubber under the vulcanization conditions. Preferred polyepoxides are obtained by reaction of epichlorohydrin with di- and polyphenols, in particular glycidyl ethers of bisphenol A or tris-4-hydroxyphenylmethane, and of phenolic resins, such as phenol/formaldehyde novolaks, phenol/xylene/formaldehyde resins and phenol/methylolurea resins with molecular weights of between 350 and 5,000. Further preferred polyepoxides are obtained by reaction of epichlorohydrin with di- and polyamines, such as e.g. diepoxides based on cyclohexylamine or aniline, or tetraepoxides based on bis-(4-amino-phenyl)-methane or epoxides based on N-containing heterocyclic compounds, in particular triglycidyl isocyanurate (TGIC) and triglycidylurazole. Further preferred polyepoxides are epoxidation products of unsaturated hydrocarbons Le A 34 080-Foreign Countries -7_ or unsaturated esters, such as e.g. epoxidized Soya oil and epoxidized cyclohexene-3-carboxylic acid esters, as well as epoxidized rubbers, such as e.g. epoxidized natural rubber, in which 10 to 70 mol% of the double bonds are epoxidized. Preferred polyepoxides have epoxide equivalent weights, i.e.
amounts of resin in grams which contain 16 g epoxidically bonded oxygen (DIN 16945), of 100 g to 1,000 g. Such polyepoxides are known and are commercially obtainable, in this context see Houben-Weyl, Methoden der Organischen Chemie [Methods of Organic Chemistry], volume XIV, pages 56-98, Georg Thieme Verlag Stuttgart 1963.
If desired, the crosslinking, i.e. the reaction between hydroxyl or carboxyl groups and the crosslinking agents, can be accelerated with known catalysts, for example with the aid of amines, such as diazabicyclooctane (DABCO), or Lewis acids, such as dibutyltin dilaurate (DBTL). The amounts of catalyst depend on the vulcanization kinetics sought, the vulcanization temperature and the amount of crosslinking agent and hydroxyl or carboxyl groups, and can easily be determined in preliminary experiments. Conventional amounts lie in the range from 0 to 3 wt.% catalyst, based on the crosslinking agent.
The vulcanization temperatures are between room temperature and 220°C, preferably 100°C to 180°C. The vulcanization time is a few minutes to several hours. The vulcanization can also be carried out in two stages in the presence of conventional crosslinking agents, since in this case it is a matter of separate crosslinking processes, that is to say, for example, by pre-crosslinking via the sulfur-free crosslinking agent and post-crosslinking with the aid of known vulcanizing agents, in particular sulfur, sulfur donors or peroxides.
Possible fillers for the rubber mixtures according to the invention are all the known fillers used in the rubber industry, these comprising both active and inactive fillers.
Le A 34 080-Foreign Countries -g_ There may be mentioned:
- highly disperse silicas prepared e.g. by precipitation of solutions of silicates or flame hydrolysis of silicon halides, with specific surface areas of 5-1,000, preferably 20-400 m2/g (BET surface area) and with primary particle sizes of 10-400 nm. The silicas can optionally also be in the form of mixed oxides with other metal oxides, such as oxides of A1, Mg, Ca, Ba, Zn, Zr or Ti;
- synthetic silicates, such as aluminium silicate or alkaline earth metal silicate, such as magnesium silicate or calcium silicate, with BET surface areas of 20-400 m2/g and primary particle diameters of 10-400 nm;
- naturally occurring silicates, such as kaolin and other naturally occurring silica;
- glass fibres and glass fibre products (mats, strands) or glass microbeads;
- metal oxides, such as zinc oxide, calcium oxide, magnesium oxide or aluminium oxide;
- metal carbonates, such as magnesium carbonate, calcium carbonate or zinc carbonate;
- metal hydroxides, such as e.g. aluminium hydroxide or magnesium hydroxide;
- carbon blacks. The carbon blacks to be used here are prepared by the flame black or furnace or gas black process and have BET surface areas of 20-200 m2/g, e.g. SAF, ISAF, HAF, FEF or GPF carbon blacks;
- rubber gels Le A 34 080-Foreign Countries - rubber powder, which has been obtained, for example, by grinding rubber vulcanization products.
Highly disperse silicas and/or carbon blacks are preferably employed as fillers.
The fillers mentioned can be employed by themselves or as a mixture. In a particularly preferred embodiment, the rubber mixtures comprise as fillers a mixture of pale fillers, such as highly disperse silicas, and carbon blacks, the mixing ratio of pale fillers to carbon blacks being 0.05 to 20, preferably 0.1 to 10.
In addition to the solution rubbers mentioned containing hydroxyl and carboxyl groups, the rubber mixtures according to the invention can also comprise other rubbers, such as natural rubber and also other synthetic rubbers.
Preferred synthetic rubbers are described, for example, by W. Hofinann, Kautschuktechnologie [Rubber Technology], Gentner Verlag, Stuttgart 1980 and I.
Franta, Elastomers and Rubber Compounding Materials, Elsevier, Amsterdam 1989.
They include, inter alia, BR - polybutadiene ABR - butadiene/acrylic acid C1-4-alkyl ester copolymers CR polychloroprene IR - polyisoprene SBR - styrene/butadiene copolymers with styrene contents of 1-60, preferably 20-50 wt.%
IIR - isobutylene/isoprene copolymers NBR - butadiene/acrylonitrile copolymers with acrylonitrile contents of 5-60, preferably 10-40 wt./>
HNBR - partly hydrogenated or completely hydrogenated NBR
rubber EPDM - ethylene/propylene/diene copolymers Le A 34 080-Foreign Countries and mixtures of these rubbers. For the production of motor vehicle tyres, natural rubber, emulsion SBR and solution SBR rubbers with a glass transition temperature above -50°C, which can optionally be modified with silyl ethers or other functional S groups in accordance with EP-A 447.066, polybutadiene rubber with a high 1,4-cis content (> 90%), which has been prepared with catalysts based on Ni, Co, Ti or Nd, and polybutadiene rubber with a vinyl content of up to 75% and mixtures thereof are of particular interest.
The rubber mixtures according to the invention can of course also comprise other rubber auxiliaries which serve, for example, for further crosslinking of the vulcanization products prepared from the rubber mixtures, or which improve the physical properties of the vulcanization products prepared from the rubber mixtures according to the invention for their specific intended use.
Sulfur or sulfur-donating compounds or peroxides are employed as additional crosslinking agents. Sulfur or sulfur-donating compounds in amounts of 0.01 to parts by wt., based on the rubber, are particularly preferred. Furthermore, as mentioned, the rubber mixtures according to the invention can comprise further auxiliaries, such as the known reaction accelerators, anti-ageing agents, heat stabilizers, light stabilizers, ozone stabilizers, processing auxiliaries, reinforcing resins, e.g. phenolic resins, steel cord adhesives, such as e.g.
silicalresorcinol/-hexamethylenetetramine or cobalt naphthenate, plasticizers, tackifiers, blowing agents, dyestuffs, pigments, waxes, extenders, organic acids, retardants, metal oxides and activators.
The rubber auxiliaries according to the invention are employed in the conventional known amounts, the amount employed depending on the later intended use of the rubber mixtures. For example, amounts of rubber auxiliaries in the range from 2 to 70 parts by wt., based on 100 parts by wt. of rubber, are conventional.
Le A 34 080-Foreign Countries As mentioned above, in addition to the solution rubber containing hydroxyl and carboxyl groups, additional rubbers can also be admixed to the rubber mixtures according to the invention. The amount thereof is conventionally in the range from 0.5 to 70, preferably 10 to 50 wt.%, based on the total amount of rubber in the rubber mixture. The amount of rubbers additionally added again depends on the particular intended use of the rubber mixtures according to the invention.
For the rubber mixtures according to the invention with a filler content of highly active silicas, the use of additional filler activators is particularly advantageous.
Preferred filler activators are sulfur-containing silyl ethers, in particular bis-(trialkoxysilyl-alkyl) polysulfides, such as are described in DE-A 2 141 159 and DE-A 2 255 577. Oligomeric and/or polymeric sulfur-containing silyl ethers corre-sponding to the description in DE-A 4 435 311 and EP-A 670 347 are moreover possible. Mercaptoalkyltrialkoxysilanes, in particular mercaptopropyltriethoxysilane and thiocyanatoalkylsilyl ethers (see DE-A 19 544 469) and silyl ethers containing amino groups, such as e.g. 3-aminopropyltriethoxysilane and N-oleyl-N-propyltri-methoxysilane are furthermore to be employed. The filler activators are employed in conventional amounts, i.e. in amounts of 0.1 to 15 parts by wt., based on 100 parts by wt. of rubber.
The rubber mixtures according to the invention can be prepared e.g. by mixing the solution rubbers containing hydroxyl and carboxyl groups with the corresponding fillers and sulfur-free crosslinking agents in suitable mixing apparatuses, such as kneaders, mills or extruders.
The present invention also provides the use of the rubber mixtures according to the invention for the preparation of vulcanization products, which in turn are used for the production of highly reinforced shaped rubber articles, in particular for the production of tyres.
Le A 34 080-Foreign Countries Examples Example 1: Solution SBR rubber containing hydroxyl groups 2.25 kg mercaptoethanol and 0.18 kg dilauroyl peroxide were added to a solution of 45 kg Buna VSL 5020-0 (solution SBR rubber with a styrene content of 20 wt.%
and a vinyl content of 50 wt.%, manufacturer: Bayer AG) in 275 kg cyclohexane at 80°C
and the mixture was stirred at 80°C for 2 hours. 0.23 kg Vulkanox 4020 (stabilizer of the 6-PPD type, manufacturer: Bayer AG) and 17.72 kg Enerthene 1849 (aromatic mineral oil, manufacturer BP) were then added and the solvent was removed by stripping with steam. After drying at 70°C in vacuo, a solution SBR
rubber extended with 37.5 phr aromatic mineral oil and with a content of hydroxyl groups of 1 wt.%
(based on the oil-free rubber), an OH number of 24 (oil-extended rubber) and a glass transition temperature of -24°C with a viscosity ML 1+4 (100°C) of SS was obtained.
Example 2: Solution SBR rubber containing carboxyl groups 0.563 kg 3-mercaptopropionic acid and 0.045 kg dilauroyl peroxide were added to a solution of 45 kg Buna VSL 5020-0 (solution SBR rubber with a styrene content of 20 wt.% and a vinyl content of 50 wt.%, manufacturer: Bayer AG) in 275 kg cyclohexane at 80°C and the mixture was stirred at 80°C for 2 hours. 0.23 kg Vulkanox 4020 (stabilizer of the 6-PPD type, manufacturer: Bayer AG) and 17.12 kg Enerthene 1849 (aromatic mineral oil, manufacturer BP) were then added and the solvent was removed by stripping with steam. After drying at 70°C in vacuo, a solution SBR rubber extended with 37.5 phr aromatic mineral oil and with a content of carboxyl groups of 0.5 wt.% (based on the oil-free rubber), an acid number of 5 (oil-extended rubber), a glass transition temperature of -29°C and a viscosity ML 1+4 (100°C) of 38 was obtained.
Le A 34 080-Foreign Countries Example 3: Sulfur-free crosslinking agent Cycloaliphatic polyisocyanate blocked with caprolactam and with a total content of NCO of 11.5%. Trade name: Crelan UI, manufacturer: Bayer AG.
S
Example 4: Sulfur-free crosslinking agent Cycloaliphatic polyuretdione free from blocking agents and with a total content of NCO of 13.5%. Trade name: Crelan VP LS 2147, manufacturer Bayer AG.
Example 5: Sulfur-free crosslinking agent triglycidyl isocyanurate (CAS-RN 2451-62-9) Example 6: Rubber mixtures The following rubber mixtures were prepared in a 1.5 1 internal mixer at 130-140°C.
The accelerator and crosslinking agent were finally admixed on a mill at 50°C.
Component Example Comparison 6.1 Exam le 6.A
mixed in the internal mixer:
hydroxylgroup-containing solution-SBR-rubber137.5 0 accordin to exam lel oil-extended solution-SBR-rubber 0 137.5 Buna VSL 5025-1 Ba er AG
Carbon black Coraxx N 339 (Degussa-Hiils50 50 AG) zincoxide 2.5 2.5 antioxidant ulkanox 4020 1 1 ozone-protective wax Antilux 654 (Rheinchemie)I .5 I .5 admixed on a mill:
sulfur-free crosslinking agent according15 15 to example 3 (sulfur 0.5 0.5 i i diphenylguanidine Vulkacit D (Bayer1 1 AG) Le A 34 080-Foreign Countries The rubber mixtures were subsequently vulcanized at 170°C for 30 minutes. The following vulcanisate properties were obtained:
Example Comparison 6.1 Example 6.A
tensile strength (MPa) 18.1 5.4 modulus at 300% elongation (MPa) 8.5 1.4 elongation at break (%) 519 975 rebound elasticity at 23C (%) 21 29 rebound elasticity at 70C (%) 54 45 difference of rebound elasticity at 33 16 23 and 70C
hardness at 23C (Shore A) 54 40 hardness at 70C (Shore A) 50 24 The results demonstate the strong reeinforcing effect (measured by means of hardness, modulus, tensile strength) of the rubber mixture of hydroxylmodified SBR-rubber and sulfur-free crosslinking agent (blocked isocynate) and the advantageous dynamic damping properties in comparison to the combination of unmodified SBR-rubber and sulfur-free crosslinking agent.
Rubber mixtures of dime rubbers containing hydroxyl and carboxyl ~rouns and sulfur-free crosslinkin~ agents . The present invention relates to rubber mixtures of dime rubbers containing hydroxyl and/or carboxyl groups, fillers and sulfur-free crosslinking agents which can crosslink the rubber via the hydroxyl or carboxyl groups, and the use thereof for the preparation of rubber vulcanization products with improved dynamic damping, improved mechanical strength, reversion resistance and adhesion to strength supports. The rubber mixtures and vulcanization products are suitable for the production of highly reinforced shaped rubber articles, in particular tyres, which have a particularly high resistance to thermal and mechanical stresses, a high wet skidding resistance, low rolling resistance and high abrasion resistance.
Numerous routes have been investigated for the production of motor vehicle tyres with reduced rolling resistance, improved wet skidding resistance, lower abrasion and higher heat resistance. The use of anionically polymerized solution rubbers containing double bonds, such as solution polybutadiene and solution styrene/-butadiene rubbers, has proved to be particularly advantageous. The advantages lie, inter alia, in the controllability of the vinyl content and of the associated glass transition temperature, a favourable cis/trans double bond ratio and the molecular branching. When used in practice, particular advantages result from this in the ratio of wet skidding resistance and rolling resistance of the tyre. l1S-A 5 227 425 thus describes the production of tyre treads from a solution SBR rubber and silica.
Emulsion and solution rubbers containing hydroxyl groups are described e.g. in EP-A 806 452, but here the rubbers are not crosslinked via the hydroxyl groups but are vulcanized in the conventional manner by crosslinking with sulfur. Due to the process, the hydroxyl contents described there for solution rubbers are in a particularly lower range (0.009 to 0.061%) and are therefore too low for effective crosslinking.
Le A 34 080-Foreign Countries A process for the preparation of solution polybutadiene rubbers containing hydroxyl and/or carboxyl groups (3.9 to 8.9 wt.%) is described, inter alia, in DE-A 2 653 144.
These rubbers are also crosslinked exclusively with sulfur, and because their strength is too low and their moduli are too low, they are not suitable as the main component in tyres.
A process for the preparation of solution rubbers containing hydroxyl groups by reaction of rubbers with particular long-chain hydroxylmercaptans is also described in EP-A 464 478. No references are given to the preparation of rubber mixtures with sulfur-free crosslinking agents which react with the hydroxyl groups and to corresponding vulcanization products.
Unsaturated rubbers which have been grafted with metal salts of unsaturated carboxylic acids are described in US-A S 962 593. Here also, crosslinking of the rubbers takes place by sulfur vulcanization. Furthermore, the content of carboxylic acid groups is considerably higher.
German Patent Applications no. 198 32 459.6, 198 52 648.2, 199 14 848.1, 199 20 788.7 and 199 20 894.8 describe solution rubbers containing hydroxyl and/or carboxyl groups with an advantageous content (0.1 to 3 wt.%) of hydroxyl and/or carboxyl groups. However, the patent applications give no indication of improved crosslinking systems which react with the functional groups.
The object of the present invention was therefore to provide mixtures of rubbers, particularly preferably solution rubbers, containing hydroxyl and/or carboxyl groups and specific crosslinking agents which react chemically with the hydroxyl or carboxyl groups under vulcanization conditions, from which tyres with improved wet skidding resistance, lower rolling resistance, high mechanical and heat resistance and improved abrasion properties can be produced.
Le A 34 080-Foreign Countries The present invention therefore provides rubber mixtures comprising at least one rubber and 10 to 800 parts by wt. of filler, based on 100 parts by wt. of rubber, wherein the rubber has been prepared by polymerization of diolefins and optionally further vinylaromatic monomers and introduction of hydroxyl and/or carboxyl groups, this rubber has a total content of 0.05 to 5 wt.% of bonded hydroxyl and/or carboxyl groups or salts thereof, and has a content of polymerized-in vinylaromatic monomers of 0 to 50 wt.% and a content of diolefins of 45 to 99.95 wt.%, the content of 1,2-bonded diolefins (vinyl content) being 0 to 80 wt.%, and 0.001 to 40 parts by wt. of a compound which is capable of crosslinking the rubber with the hydroxyl or carboxyl groups of the rubber (so-called sulfur-free crosslinking agent), and optionally further rubbers, rubber auxiliaries and crosslinking agents.
Rubber mixtures according to the invention which are preferred are those in which the rubber constituent has a content of bonded hydroxyl and/or carboxyl groups or salts thereof of 0.1 to 3 wt.% in total, and has a content of polymerized-in vinylaromatic monomers of 0 to 40 wt.%, particularly preferably 10 to 40 wt.%, and a content of diolefins of 99.9 to 60 wt.%, the content of 1,2-bonded diolefins (vinyl content) being in the range from 5 to 55 wt.%, and which have a content of 0.1 to 20 parts by wt. of sulfur-free crosslinking agent of the abovementioned type.
The amount of fillers is preferably 20 to 200 parts by wt.
Diolefins which are used according to the invention for the polymerization are 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 particularly preferably employed.
Examples which may be mentioned of vinylaromatic monomers which can be employed for the polymerization are styrene, o-, m- and p-methylstyrene, p-tert-butylstyrene, a-methylstyrene, vinylnaphthalene, divinylbenzene, trivinylbenzene and/or divinylnaphthalene. Styrene is particularly preferably employed.
Le A 34 080-Foreign Countries The rubbers based on diolefins and optionally further vinylaromatic monomers which are to be employed according to the invention in the rubber mixtures have average molecular weights (number-average) of 50,000 to 2,000,000, preferably 100,000 to 1,000,000, and glass transition temperatures of -110°C to +20°C, preferably -100°C
to 0°C, and Mooney viscosities ML 1+4 (100°C) of 10 to 200, preferably 30 to 150.
In addition to the hydroxyl and carboxylic acid groups or salts thereof, the rubbers according to the invention can also have further known functional groups, such as carboxylic acid ester, carboxylic acid amide or sulfonic acid groups.
Solution rubbers containing hydroxyl and carboxyl groups are particularly preferred, in particular such as are described in the abovementioned German patent applications and in DE-A 2 653 144 and EP-A 464 478.
Possible sulfur-free crosslinking agents in the sense according to the invention are all the polyfunctional compounds which are capable of bringing about vulcanization of the rubber mixture, i.e. crosslinking to form covalent chemical bonds, exclusively via the hydroxyl or carboxyl groups. In this connection, the term "sulfur-free" is understood as meaning that the compounds contain no vulcanization-active sulfur-containing groups. Crosslinking agents which have sulfur-containing groups which are stable under the vulcanization conditions, such as e.g. sulfone or monothioether groups, can also be employed in the context according to the invention.
Suitable crosslinking agents in the context of the invention are, above all, polyisocyanates, polyuretdiones, blocked polyisocyanates and/or polyepoxides. Particularly preferred classes of crosslinking agents are:
(A) Polyisocyanates, such as e.g. hexamethylene-diisocyanate (HDI), isophorone-diisocyanate (IPDI), toluene-diisocyanate (TDI), 4,4'-diisocyanatodiphenyl-methane (MDI), 1,6-diisocyanato-2,2,4-trimethylhexane (IPDI), tris-(4-isocyanatophenyl)-methane, phosphoric acid tris-(4-isocyanato-phenyl ester), Le A 34 080-Foreign Countries thiophosphoric acid tris-(4-isocyanato-phenyl ester) and oligomerization products thereof which have been obtained by reaction of the low molecular weight diisocyanates mentioned with diols or polyalcohols, in particular ethylene glycol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane or penta-erythritol, and have a residual content of free isocyanate groups, furthermore oligomerization products which have been obtained by reaction of the low molecular weight diisocyanates mentioned with polyesters containing hydroxyl groups, such as e.g. polyesters based on adipic acid and butanediol and hexanediol and having molecular weights of between 400 and 3,000, or by reaction with polyethers containing hydroxyl groups, such as polyethylene glycols or polypropylene glycols, or polytetrahydrofurans with molecular weights of 150 to 3,000 and have a residual content of free isocyanate groups, furthermore oligomerization products which have been obtained by reaction of the low molecular weight diisocyanates mentioned with amines or 1 S polyamines, in particular ammonia, diaminobutane or diaminohexane, and have a residual content of free isocyanate groups, or oligomerization products which have been obtained by reaction of the low molecular weight diisocyanates mentioned with water or by dimerization or trimerization, such as e.g. dimerized toluene-diisocyanate (Desmodur TT) and trimerized toluene-diisocyanate, or aliphatic uretdiones and polyuretdiones containing isocyanate groups, e.g. based on isophorone-diisocyanate, and have a residual content of free isocyanate groups. Preferred contents of free isocyanate groups are in the range from 2.5 to 25 wt.%. Such polyisocyanates are known and are commercially obtainable, in this context see Houben-Weyl, Methoden der Organischen Chemie [Methods of Organic Chemistry], volume XIV, pages 56-98, Georg Thieme Verlag Stuttgart 1963, and the commercial products of the Desmodur and Crelan series (Bayer AG);
Le A 34 080-Foreign Countries (B) Blocked polyisocyanates which react with the hydroxyl and/or carboxyl groups of the rubber under the vulcanization conditions. These include all the polyisocyanates mentioned under (A), the isocyanate groups in each case being blocked with suitable splitting-off groups which split off again at a higher temperature and thereby liberate the isocyanate groups. Suitable splitting-off groups are, in particular, caprolactam, malonic acid esters, phenol and alkylphenols, such as e.g. nonylphenol, as well as imidazole and sodium hydrogen sulfite. Polyisocyanates blocked with caprolactam, malonic esters and alkylphenol, in particular those based on toluene-diisocyanate or trimerized toluene-diisocyanate and isophorone-diisocyanate, are particularly preferred. Preferred blocked polyisocyanates are also obtained by dimerization of the isocyanate groups to uretdiones and polyuretdiones.
Preferred contents of blocked isocyanate groups are in the range from 2.5 to wt.%. Such blocked polyisocyanates are known and are commercially 15 obtainable, in this context see Houben-Weyl, Methoden der Organischen Chemie [Methods of Organic Chemistry], volume XIV, pages 56-98, Georg Thieme Verlag Stuttgart 1963, and the commercial products of the Desmodur and Crelan series (Bayer AG);
20 (C) Polyepoxides which react with the hydroxyl or carboxyl groups of the rubber under the vulcanization conditions. Preferred polyepoxides are obtained by reaction of epichlorohydrin with di- and polyphenols, in particular glycidyl ethers of bisphenol A or tris-4-hydroxyphenylmethane, and of phenolic resins, such as phenol/formaldehyde novolaks, phenol/xylene/formaldehyde resins and phenol/methylolurea resins with molecular weights of between 350 and 5,000. Further preferred polyepoxides are obtained by reaction of epichlorohydrin with di- and polyamines, such as e.g. diepoxides based on cyclohexylamine or aniline, or tetraepoxides based on bis-(4-amino-phenyl)-methane or epoxides based on N-containing heterocyclic compounds, in particular triglycidyl isocyanurate (TGIC) and triglycidylurazole. Further preferred polyepoxides are epoxidation products of unsaturated hydrocarbons Le A 34 080-Foreign Countries -7_ or unsaturated esters, such as e.g. epoxidized Soya oil and epoxidized cyclohexene-3-carboxylic acid esters, as well as epoxidized rubbers, such as e.g. epoxidized natural rubber, in which 10 to 70 mol% of the double bonds are epoxidized. Preferred polyepoxides have epoxide equivalent weights, i.e.
amounts of resin in grams which contain 16 g epoxidically bonded oxygen (DIN 16945), of 100 g to 1,000 g. Such polyepoxides are known and are commercially obtainable, in this context see Houben-Weyl, Methoden der Organischen Chemie [Methods of Organic Chemistry], volume XIV, pages 56-98, Georg Thieme Verlag Stuttgart 1963.
If desired, the crosslinking, i.e. the reaction between hydroxyl or carboxyl groups and the crosslinking agents, can be accelerated with known catalysts, for example with the aid of amines, such as diazabicyclooctane (DABCO), or Lewis acids, such as dibutyltin dilaurate (DBTL). The amounts of catalyst depend on the vulcanization kinetics sought, the vulcanization temperature and the amount of crosslinking agent and hydroxyl or carboxyl groups, and can easily be determined in preliminary experiments. Conventional amounts lie in the range from 0 to 3 wt.% catalyst, based on the crosslinking agent.
The vulcanization temperatures are between room temperature and 220°C, preferably 100°C to 180°C. The vulcanization time is a few minutes to several hours. The vulcanization can also be carried out in two stages in the presence of conventional crosslinking agents, since in this case it is a matter of separate crosslinking processes, that is to say, for example, by pre-crosslinking via the sulfur-free crosslinking agent and post-crosslinking with the aid of known vulcanizing agents, in particular sulfur, sulfur donors or peroxides.
Possible fillers for the rubber mixtures according to the invention are all the known fillers used in the rubber industry, these comprising both active and inactive fillers.
Le A 34 080-Foreign Countries -g_ There may be mentioned:
- highly disperse silicas prepared e.g. by precipitation of solutions of silicates or flame hydrolysis of silicon halides, with specific surface areas of 5-1,000, preferably 20-400 m2/g (BET surface area) and with primary particle sizes of 10-400 nm. The silicas can optionally also be in the form of mixed oxides with other metal oxides, such as oxides of A1, Mg, Ca, Ba, Zn, Zr or Ti;
- synthetic silicates, such as aluminium silicate or alkaline earth metal silicate, such as magnesium silicate or calcium silicate, with BET surface areas of 20-400 m2/g and primary particle diameters of 10-400 nm;
- naturally occurring silicates, such as kaolin and other naturally occurring silica;
- glass fibres and glass fibre products (mats, strands) or glass microbeads;
- metal oxides, such as zinc oxide, calcium oxide, magnesium oxide or aluminium oxide;
- metal carbonates, such as magnesium carbonate, calcium carbonate or zinc carbonate;
- metal hydroxides, such as e.g. aluminium hydroxide or magnesium hydroxide;
- carbon blacks. The carbon blacks to be used here are prepared by the flame black or furnace or gas black process and have BET surface areas of 20-200 m2/g, e.g. SAF, ISAF, HAF, FEF or GPF carbon blacks;
- rubber gels Le A 34 080-Foreign Countries - rubber powder, which has been obtained, for example, by grinding rubber vulcanization products.
Highly disperse silicas and/or carbon blacks are preferably employed as fillers.
The fillers mentioned can be employed by themselves or as a mixture. In a particularly preferred embodiment, the rubber mixtures comprise as fillers a mixture of pale fillers, such as highly disperse silicas, and carbon blacks, the mixing ratio of pale fillers to carbon blacks being 0.05 to 20, preferably 0.1 to 10.
In addition to the solution rubbers mentioned containing hydroxyl and carboxyl groups, the rubber mixtures according to the invention can also comprise other rubbers, such as natural rubber and also other synthetic rubbers.
Preferred synthetic rubbers are described, for example, by W. Hofinann, Kautschuktechnologie [Rubber Technology], Gentner Verlag, Stuttgart 1980 and I.
Franta, Elastomers and Rubber Compounding Materials, Elsevier, Amsterdam 1989.
They include, inter alia, BR - polybutadiene ABR - butadiene/acrylic acid C1-4-alkyl ester copolymers CR polychloroprene IR - polyisoprene SBR - styrene/butadiene copolymers with styrene contents of 1-60, preferably 20-50 wt.%
IIR - isobutylene/isoprene copolymers NBR - butadiene/acrylonitrile copolymers with acrylonitrile contents of 5-60, preferably 10-40 wt./>
HNBR - partly hydrogenated or completely hydrogenated NBR
rubber EPDM - ethylene/propylene/diene copolymers Le A 34 080-Foreign Countries and mixtures of these rubbers. For the production of motor vehicle tyres, natural rubber, emulsion SBR and solution SBR rubbers with a glass transition temperature above -50°C, which can optionally be modified with silyl ethers or other functional S groups in accordance with EP-A 447.066, polybutadiene rubber with a high 1,4-cis content (> 90%), which has been prepared with catalysts based on Ni, Co, Ti or Nd, and polybutadiene rubber with a vinyl content of up to 75% and mixtures thereof are of particular interest.
The rubber mixtures according to the invention can of course also comprise other rubber auxiliaries which serve, for example, for further crosslinking of the vulcanization products prepared from the rubber mixtures, or which improve the physical properties of the vulcanization products prepared from the rubber mixtures according to the invention for their specific intended use.
Sulfur or sulfur-donating compounds or peroxides are employed as additional crosslinking agents. Sulfur or sulfur-donating compounds in amounts of 0.01 to parts by wt., based on the rubber, are particularly preferred. Furthermore, as mentioned, the rubber mixtures according to the invention can comprise further auxiliaries, such as the known reaction accelerators, anti-ageing agents, heat stabilizers, light stabilizers, ozone stabilizers, processing auxiliaries, reinforcing resins, e.g. phenolic resins, steel cord adhesives, such as e.g.
silicalresorcinol/-hexamethylenetetramine or cobalt naphthenate, plasticizers, tackifiers, blowing agents, dyestuffs, pigments, waxes, extenders, organic acids, retardants, metal oxides and activators.
The rubber auxiliaries according to the invention are employed in the conventional known amounts, the amount employed depending on the later intended use of the rubber mixtures. For example, amounts of rubber auxiliaries in the range from 2 to 70 parts by wt., based on 100 parts by wt. of rubber, are conventional.
Le A 34 080-Foreign Countries As mentioned above, in addition to the solution rubber containing hydroxyl and carboxyl groups, additional rubbers can also be admixed to the rubber mixtures according to the invention. The amount thereof is conventionally in the range from 0.5 to 70, preferably 10 to 50 wt.%, based on the total amount of rubber in the rubber mixture. The amount of rubbers additionally added again depends on the particular intended use of the rubber mixtures according to the invention.
For the rubber mixtures according to the invention with a filler content of highly active silicas, the use of additional filler activators is particularly advantageous.
Preferred filler activators are sulfur-containing silyl ethers, in particular bis-(trialkoxysilyl-alkyl) polysulfides, such as are described in DE-A 2 141 159 and DE-A 2 255 577. Oligomeric and/or polymeric sulfur-containing silyl ethers corre-sponding to the description in DE-A 4 435 311 and EP-A 670 347 are moreover possible. Mercaptoalkyltrialkoxysilanes, in particular mercaptopropyltriethoxysilane and thiocyanatoalkylsilyl ethers (see DE-A 19 544 469) and silyl ethers containing amino groups, such as e.g. 3-aminopropyltriethoxysilane and N-oleyl-N-propyltri-methoxysilane are furthermore to be employed. The filler activators are employed in conventional amounts, i.e. in amounts of 0.1 to 15 parts by wt., based on 100 parts by wt. of rubber.
The rubber mixtures according to the invention can be prepared e.g. by mixing the solution rubbers containing hydroxyl and carboxyl groups with the corresponding fillers and sulfur-free crosslinking agents in suitable mixing apparatuses, such as kneaders, mills or extruders.
The present invention also provides the use of the rubber mixtures according to the invention for the preparation of vulcanization products, which in turn are used for the production of highly reinforced shaped rubber articles, in particular for the production of tyres.
Le A 34 080-Foreign Countries Examples Example 1: Solution SBR rubber containing hydroxyl groups 2.25 kg mercaptoethanol and 0.18 kg dilauroyl peroxide were added to a solution of 45 kg Buna VSL 5020-0 (solution SBR rubber with a styrene content of 20 wt.%
and a vinyl content of 50 wt.%, manufacturer: Bayer AG) in 275 kg cyclohexane at 80°C
and the mixture was stirred at 80°C for 2 hours. 0.23 kg Vulkanox 4020 (stabilizer of the 6-PPD type, manufacturer: Bayer AG) and 17.72 kg Enerthene 1849 (aromatic mineral oil, manufacturer BP) were then added and the solvent was removed by stripping with steam. After drying at 70°C in vacuo, a solution SBR
rubber extended with 37.5 phr aromatic mineral oil and with a content of hydroxyl groups of 1 wt.%
(based on the oil-free rubber), an OH number of 24 (oil-extended rubber) and a glass transition temperature of -24°C with a viscosity ML 1+4 (100°C) of SS was obtained.
Example 2: Solution SBR rubber containing carboxyl groups 0.563 kg 3-mercaptopropionic acid and 0.045 kg dilauroyl peroxide were added to a solution of 45 kg Buna VSL 5020-0 (solution SBR rubber with a styrene content of 20 wt.% and a vinyl content of 50 wt.%, manufacturer: Bayer AG) in 275 kg cyclohexane at 80°C and the mixture was stirred at 80°C for 2 hours. 0.23 kg Vulkanox 4020 (stabilizer of the 6-PPD type, manufacturer: Bayer AG) and 17.12 kg Enerthene 1849 (aromatic mineral oil, manufacturer BP) were then added and the solvent was removed by stripping with steam. After drying at 70°C in vacuo, a solution SBR rubber extended with 37.5 phr aromatic mineral oil and with a content of carboxyl groups of 0.5 wt.% (based on the oil-free rubber), an acid number of 5 (oil-extended rubber), a glass transition temperature of -29°C and a viscosity ML 1+4 (100°C) of 38 was obtained.
Le A 34 080-Foreign Countries Example 3: Sulfur-free crosslinking agent Cycloaliphatic polyisocyanate blocked with caprolactam and with a total content of NCO of 11.5%. Trade name: Crelan UI, manufacturer: Bayer AG.
S
Example 4: Sulfur-free crosslinking agent Cycloaliphatic polyuretdione free from blocking agents and with a total content of NCO of 13.5%. Trade name: Crelan VP LS 2147, manufacturer Bayer AG.
Example 5: Sulfur-free crosslinking agent triglycidyl isocyanurate (CAS-RN 2451-62-9) Example 6: Rubber mixtures The following rubber mixtures were prepared in a 1.5 1 internal mixer at 130-140°C.
The accelerator and crosslinking agent were finally admixed on a mill at 50°C.
Component Example Comparison 6.1 Exam le 6.A
mixed in the internal mixer:
hydroxylgroup-containing solution-SBR-rubber137.5 0 accordin to exam lel oil-extended solution-SBR-rubber 0 137.5 Buna VSL 5025-1 Ba er AG
Carbon black Coraxx N 339 (Degussa-Hiils50 50 AG) zincoxide 2.5 2.5 antioxidant ulkanox 4020 1 1 ozone-protective wax Antilux 654 (Rheinchemie)I .5 I .5 admixed on a mill:
sulfur-free crosslinking agent according15 15 to example 3 (sulfur 0.5 0.5 i i diphenylguanidine Vulkacit D (Bayer1 1 AG) Le A 34 080-Foreign Countries The rubber mixtures were subsequently vulcanized at 170°C for 30 minutes. The following vulcanisate properties were obtained:
Example Comparison 6.1 Example 6.A
tensile strength (MPa) 18.1 5.4 modulus at 300% elongation (MPa) 8.5 1.4 elongation at break (%) 519 975 rebound elasticity at 23C (%) 21 29 rebound elasticity at 70C (%) 54 45 difference of rebound elasticity at 33 16 23 and 70C
hardness at 23C (Shore A) 54 40 hardness at 70C (Shore A) 50 24 The results demonstate the strong reeinforcing effect (measured by means of hardness, modulus, tensile strength) of the rubber mixture of hydroxylmodified SBR-rubber and sulfur-free crosslinking agent (blocked isocynate) and the advantageous dynamic damping properties in comparison to the combination of unmodified SBR-rubber and sulfur-free crosslinking agent.
Claims (17)
1. Rubber mixtures comprising at least one rubber and 10 to 800 parts by wt. of filler, based on 100 parts by wt. of rubber, wherein the rubber has been prepared by polymerization of diolefins and optionally further vinylaromatic monomers and introduction of hydroxyl and/or carboxyl groups, this rubber has a total content of 0.05 to 5 wt.% of bonded hydroxyl and/or carboxyl groups or salts thereof, and has a content of polymerized-in vinylaromatic monomers of 0 to 50 wt.% and a content of diolefins of 45 to 99.95 wt.%, the content of 1,2-bonded diolefins (vinyl content) being 0 to 80 wt.%, and 0.001 to 40 parts by wt. of an agent which is capable of crosslinking the rubber with the hydroxyl or carboxyl groups of the rubber.
2. Rubber mixtures according to claim 1, characterized in that the rubber mixtures comprise 20 to 200 parts by wt. of a filler, based on 100 parts by wt. of rubber.
3. Rubber mixtures according to claim 1 or 2, characterized in that the rubbers have a total content of bonded hydroxyl and/or carboxyl groups or salts thereof of 0.1 to 3 wt.%.
4. Rubber mixtures according to any one of claims 1 to 3, characterized in that the rubbers have a content of polymerized-in vinylaromatic monomers of 0 to 40 wt.% and a content of diolefins of 99.9 to 60 wt.%, wherein the content of 1,2-bonded diolefins (vinyl content) is 5 to 55 wt.%.
5. Rubber mixtures according to claim 4, wherein the amount of crosslinking agent is in the range of from 0.1 to 20 parts by wt.
6. Rubber mixtures according to any one of claims 1 to 5, characterized in that the crosslinking agent employed is a polyisocyanate, a polyuretdione, a blocked polyisocyanate and/or a polyepoxide.
7. Rubber mixtures according to claim 6, wherein the crosslinking agent is a cycloaliphatic polyisocyanate.
8. Rubber mixtures according to claim 6, wherein the crosslinking agent is a cycloaliphatic polyuretdione.
9. Rubber mixtures according to claim 6, wherein the crosslinking agent is a triglycidyl isocyanurate.
10. Rubber mixtures according to any one of claims 1 to 9, comprising one or more further natural or synthetic rubbers.
11. Rubber mixtures according to any one of claims 1 to 10, comprising further crosslinking agents.
12. Rubber mixtures according to claim 11, wherein the further crosslinking agents are sulfur compounds, sulfur-donating compounds or peroxides.
13. Rubber compositions formed by crosslinking a rubber mixture, according to any one of claims 1 to 12, with its hydroxyl or carboxyl groups.
14. Process for making highly reinforced rubber, wherein a rubber mixture according to any one of claims 1 to 12 is crosslinked with its hydroxyl or carboxyl groups, and then vulcanized.
15. Use of the rubber mixtures according to any one of claims 1 to 14 for the production of highly reinforced shaped rubber.
16. Use according to claim 15, wherein the rubber is used
17 for the production of tyres.
17. Use according to claim 15, wherein the rubber is used for the production of tyre components.
17. Use according to claim 15, wherein the rubber is used for the production of tyre components.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19956118A DE19956118A1 (en) | 1999-11-22 | 1999-11-22 | Rubber mixtures of diene rubbers containing hydroxyl and carboxyl groups and sulfur-free crosslinking agents |
| DE19956118.4 | 1999-11-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2326305A1 true CA2326305A1 (en) | 2001-05-22 |
Family
ID=7929902
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002326305A Abandoned CA2326305A1 (en) | 1999-11-22 | 2000-11-17 | Rubber mixtures of diene rubbers containing hydroxyl and carboxyl groups and sulfur-free crosslinking agents |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP1101789A1 (en) |
| JP (1) | JP2001187827A (en) |
| KR (1) | KR20010051841A (en) |
| CN (1) | CN1296989A (en) |
| CA (1) | CA2326305A1 (en) |
| DE (1) | DE19956118A1 (en) |
| MX (1) | MXPA00011414A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130281609A1 (en) * | 2007-09-15 | 2013-10-24 | Lanxess Deutschland Gmbh | Functionalized high vinyl diene rubbers |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10060519A1 (en) * | 2000-08-07 | 2002-02-28 | Continental Ag | The rubber mixture, for a vehicle pneumatic tire, where at least one rubber in the mixture is modified by covalent bonding using a modifying reagent |
| KR100429071B1 (en) * | 2001-06-25 | 2004-04-29 | 한국타이어 주식회사 | The rubber composition for tire treads |
| JP4552551B2 (en) * | 2004-07-20 | 2010-09-29 | 横浜ゴム株式会社 | Rubber composition for tire tread |
| JP4639875B2 (en) * | 2005-03-18 | 2011-02-23 | 住友化学株式会社 | Modified diene polymer rubber, method for producing the same, and rubber composition |
| ATE474727T1 (en) * | 2006-03-03 | 2010-08-15 | Pirelli | TIRE MADE OF A CROSS-LINKED ELASTOMIC COMPOSITION |
| JP5374803B2 (en) * | 2006-03-13 | 2013-12-25 | 横浜ゴム株式会社 | Rubber composition for tire tread |
| DE102009023915A1 (en) | 2009-05-27 | 2010-12-02 | Rhein-Chemie Rheinau Gmbh | Mixtures of functionalized diene rubbers with trimethylolpropane and fatty acid, a process for their preparation and their use |
| DE112013005884T5 (en) * | 2013-01-09 | 2015-08-27 | Toyo Tire & Rubber Co., Ltd. | Modified diene polymer, process for its preparation, gum composition and pneumatic tires |
| EP3241853A1 (en) | 2016-05-04 | 2017-11-08 | Trinseo Europe GmbH | Elastomeric polymers with thioether modified spine |
| CN110724475B (en) * | 2019-10-23 | 2021-04-30 | 青岛东方雨虹建筑材料有限公司 | Reactive adhesive layer of modified coated rubber powder, preparation method of reactive adhesive layer and pre-paved high-molecular waterproof coiled material |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4042619A (en) * | 1965-05-03 | 1977-08-16 | E. I. Du Pont De Nemours And Company | Derivatives of carboxy-terminated polybutadienes |
| ZA733319B (en) * | 1972-06-08 | 1974-04-24 | Firestone Tire & Rubber Co | Tire treads |
| US4104265A (en) * | 1975-01-30 | 1978-08-01 | Compagnie Generale Des Etablissements Michelin | Vulcanization process for preparation of polyurethane tires |
-
1999
- 1999-11-22 DE DE19956118A patent/DE19956118A1/en not_active Withdrawn
-
2000
- 2000-11-09 EP EP00124209A patent/EP1101789A1/en not_active Withdrawn
- 2000-11-17 CA CA002326305A patent/CA2326305A1/en not_active Abandoned
- 2000-11-21 JP JP2000354197A patent/JP2001187827A/en active Pending
- 2000-11-21 MX MXPA00011414A patent/MXPA00011414A/en unknown
- 2000-11-21 KR KR1020000069197A patent/KR20010051841A/en not_active Application Discontinuation
- 2000-11-22 CN CN00128452A patent/CN1296989A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130281609A1 (en) * | 2007-09-15 | 2013-10-24 | Lanxess Deutschland Gmbh | Functionalized high vinyl diene rubbers |
Also Published As
| Publication number | Publication date |
|---|---|
| KR20010051841A (en) | 2001-06-25 |
| CN1296989A (en) | 2001-05-30 |
| MXPA00011414A (en) | 2002-05-23 |
| DE19956118A1 (en) | 2001-05-23 |
| EP1101789A1 (en) | 2001-05-23 |
| JP2001187827A (en) | 2001-07-10 |
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