MXPA97001545A - Na, k and li salts of sil compounds - Google Patents

Abstract

The present invention relates to the compounds of the formula (See Formula) wherein R1, R2 and R3 are independently selected from alkoxy radicals having from 1 to 8 carbon atoms, x is 0 or an integer from 1 to 10; and Y is Li, K or Na. These compounds can be used as silica couplers in compositions of Caucasian

Description

"Na, K and Li SALTS FROM SILOXI COMPOUNDS" FIELD OF THE INVENTION The present invention relates to salts of Na and Li of siloxy compounds which can be used as silica couplers in rubber. The present invention also relates to a filled or silica-laden rubber composition containing sodium, potassium or lithium salts of the siloxy compounds and the processing of a sulfur-curable rubber composition containing silica and sodium, potassium salts. or lithium of siloxy compounds.

BACKGROUND OF THE INVENTION Sulfur-containing organosilicon compounds are useful as reactive coupling agents between rubber and silica fillers or fillers, providing improved physical properties. They are also useful as adhesion primers for glass substrates, metals and other substrates. The North American Patents Numbers 3,842,111, 3,873,489 and 3,978,103 disclose the preparation of various organosilicon compounds containing sulfur.

These organosilicon compounds are prepared by reacting (a) 2 moles of a compound of the formula Z-Alc-hal where hal is a chlorine, bromine or iodine; Z is Rl Rl ^ 2 I I I If R] _, Si R2 or Si R2 I I I R2 R2 R2 wherein R ^ is an alkyl of 1 to 4 carbon atoms or phenyl and R2 is alkoxy of 1 to 8 carbon atoms; or cycloalkoxy of 5 to 8 carbon atoms; or alkylmercapto with 1 to 8 carbon atoms: Ale is a divalent aliphatic hydrocarbon or unsaturated hydrocarbon or a cyclic hydrocarbon containing from 1 to 18 carbon atoms; with (b) 1 mole of a compound of the formula wherein Me is ammonium or a metal atom and n is an integer from 2 to 6.

COMPENDIUM OF THE INVENTION The present invention relates to the use of sodium, potassium and lithium salts of siloxy compounds.

DETAILED DESCRIPTION OF THE INVENTION A compound of the formula is disclosed RJ R2 Si _ (_ CH2 _). -x CH2 R- or R < II - - wherein R ^, R ^ and R3 are independently selected from alkoxy radicals having from 1 to 8 carbon atoms, x is 0 or an integer from 1 to 10; and Y is Li, K or Na. Also disclosed is a method for processing a rubber composition filled or filled with silica comprising (i) 100 parts by weight of at least one sulfur vulcanizable elastomer selected from the homopolymers and copolymers of conjugated diene and copolymers of at least one conjugated diene and an aromatic vinyl compound; (ii) from 10 to 220 phr of silica precipitated into particles; (iii) from .05 to 10 phr of a compound of the formula.

RJ R2 Si _ (_ CH2 _.}. _? CH2 R * wherein R1, R and R3 are independently selected from alkoxy radicals having from 1 to 8 carbon atoms, x is 0 or an integer from 1 to 10; and Y is Li, K or Na. Also disclosed is a sulfur vulcanizable rubber composition comprising an elastomer containing olefinic unsaturation, silica and a compound of the formula Rl R2 Si _ (_ CH2 _). -x CH2 R3 wherein R1, R2 and R3 are independently selected from alkoxy radicals having from 1 to 8 carbon atoms, x is 0 or an integer from 1 to 10; and Y is Li, K or Na. The present invention can be used to process vulcanizable elastomers or rubbers containing sulfur containing olefinic unsaturation. The phrase "rubber or elastomer containing olefinic unsaturation" is intended to include both natural rubber and its various raw and regenerated forms as well as the various synthetic rubbers. In the description of this invention, the terms "rubber" and "elastomer" can be used interchangeably, unless otherwise stated. The terms "rubber composition", "mixed rubber" and "rubber compound" are used interchangeably to refer to rubber that has been combined or mixed with different ingredients and materials and these terms are well known to those skilled in the art. technique of mixing rubber or combining or stirring rubber. Representative synthetic polymers are the homopolymerization products of butadiene and its homologs and derivatives, for example, methylbutadiene, diethylbutadiene and pentadiene as well as copolymers such as those formed of butadiene and its homologues or derivatives, with other unsaturated monomers. Among the latter are acetylenes, for example acetylene vinyl; olefins, for example, isobutylene, which is copolymerized with isoprene to form the butyl rubber; vinyl compounds, for example, acrylic acid, acrylonitrile (which polymerizes with butadiene to form NBR), methacrylic acid and styrene, the latter compound being polymerized with butadiene to form SBR, as well as the vinyl esters and the various aldehydes, unsaturated ketones and ethers, e.g., acrolein, methylisopropenyl ketone and vinylethyl ether. Specific examples of synthetic rubbers include neoprene (polychloroprene), polybutadiene (including cis-1, -polybutadiene), polyisoprene (including cis-1,4-polyisoprene), butyl rubber, halobutyl rubber such as chlorobutyl rubber or rubber. bromobutyl, styrene / isoprene / butadiene rubber, copolymers of 1,3-butadiene or isoprene with monomers such as styrene, acrylonitrile and methyl methacrylate, as well as ethylene / propylene terpolymers, also known as ethylene / propylene / diene monomer ( EPDM), and in particular, ethylene / propylene / dicyclopentadiene terpolymers, further examples of rubber that can be used include star-bonded silicon-coupled and tin-coupled branched polymers. The preferred rubber or elastomers are polybutadiene and SBR. In still another aspect of the present invention, it is preferred to use a rubber or elastomer containing olefinic unsaturation and an additional functional group reactive with the Na or Li salts of the siloxy compounds of the present invention. Representative functional groups include halogens, such as Cl and Br; alkoxy groups such as methoxy groups; and pseudohalogens such as -SCN. In one aspect, the rubber is preferably at least two diene-based rubbers. For example, a combination of two or more rubbers such as cis 1-polyisoprene rubber (natural or synthetic, even when natural is preferred), 3-polyisoprene rubber, styrene / isoprene / butadiene rubber, rubbers is preferred. of styrene / butadiene derived from the emulsion and solution polymerization, cis 1,4-polybutadiene rubbers and butadiene / acrylonitrile copolymers prepared by emulsion polymerization. In one aspect of this invention, a styrene / butadiene derivative by emulsion polymerization (E-SBR) could be used which has a bound styrene content of from about 20 percent to about 28 percent, for some applications, an E-SBR having a medium to relatively high bound content of styrene, namely, a bound styrene content of from about 30 percent to about 45 percent. The relatively high styrene content of from about 30 to about 45 for the E-SBR can be considered beneficial for purposes of improving the traction, or slip resistance of the bearing surface of the rim. The presence of E-SBR itself is considered beneficial for the purpose of improving the processability of the mixture of the uncured elastomer composition, especially in comparison with a use of an SBR (E-SBR) prepared by solution polymerization. By E-SBR, prepared by emulsion polymerization, it is meant that styrene and 1,3-butadiene are copolymerized in an aqueous emulsion. These are well known to those skilled in the art. The bound styrene content can vary, for example, from about 5 percent to about 50 percent. In one aspect, the E-SBR may also contain acrylonitrile to form a terpolymer rubber such as E-SBAR, in amounts, for example, from about 2 percent to about 30 percent by weight of bound acrylonitrile in the terpolymer. Styrene / butadiene / acrylonitrile copolymer rubbers prepared by emulsion polymerization containing from about 2 percent to about 40 weight percent bound acrylonitrile in the copolymer are also proposed as well as diene-based rubbers for use in this invention. SBR (S-SBR) prepared by solution polymerization typically has a bound styrene content within the range of about 5 percent to about 50 percent, preferably from about 9 percent to about 36 percent. The S-SBR can be conveniently prepared, for example, by organolithium catalysis in the presence of an organic hydrocarbon solvent. The object of using the S-SBR is for improved rim rolling resistance as a result of the lower hysteresis when used in a tread surface composition. The 3,4-polyisoprene (3,4-PI) rubber is considered beneficial for an object of improving tire traction when used in a tire tread composition. The 3,4-PI and the use thereof are more fully described in U.S. Patent No. 5,087,668 which is incorporated herein by reference. The Tg refers to the glass transition temperature which can be conveniently determined by a differential scanning calorimeter at a heating rate of 10 ° C per minute. The cis 1-polybutadiene rubber (BR) is considered to be beneficial for an object of improving wear on the tread surface of the rim, or tread. This BR can be prepared, for example, by polymerization by organic solution of 1,3-butadiene. The 1 - BR can be conveniently characterized for example because it has at least 90 percent cis 1 content,4. Cis 1, polyisoprene and the natural rubber of cis 1, polyisoprene are well known to those skilled in the rubber art. The term "phr" as used herein and in accordance with conventional practice, refers to "parts by weight of a respective material per 100 parts by weight of rubber or elastomer". The sodium, potassium or lithium salts of the siloxy compounds used in the present invention are of the formula RJ R2 Yes _, < _ CH2 -) _? CH2 R2 Si -h- CH2 _) -X CH2 II wherein R1, R and R3 are independently selected from alkoxy radicals having from 1 to 8 carbon atoms, x is 0 or an integer from 1 to 10; and Y is Li, K or Na. Preferably, each R-, R and R3 are alkoxy radicals having from 1 to 3 carbon atoms, x is 0 or an integer from 1 to 3. The salts of the formula I or II may comprise a high purity product or a mixture of products of both formulas. For example, it is proposed here that not only the high purity salts of the formula I or II are used, but also mixtures of the salts of the formula I or mixtures of the salts of the formula II can be used, like when some of the salts contain sodium, they contain potassium and some of the salts are salts that contain lithium. Representative of the salts of the formula I include but are not limited to trimethoxysilane of 3-lithium thiolate propyl, trimethoxysilane of 3-potassium-thiolate propyl, trimethoxysilane of 3-sodium-thiolate propyl, triethoxysilane of 3-lithio-thiolate propyl, 3-potassium triethoxysilane-thiolate propyl, 3-sodio-thiolate propyl triethoxysilane, 3-lithium-thiolate propyl tributhoxysilane 3-potassium-thiolate propyl trityloxysilane 3-sodium-thiolate propyl trihexoxysilane tributoxisilane lithium-thiolate propyl trihexoxysilane 3-potassium-thiolate propyl trihexoxysilane 3-sodium-thiolate propyl trioctoxysilane 3-lithium-thiolate propyl trioctoxysilane 3-potassium-thiolate propyl trioctoxysilane 3-sodium-thiolate propyl methoxyethoxybutoxysilane 3-lithium- thiolate propyl methoxyethoxybutoxysilane of 3-potassium-thiolate propyl and methoxyethoxybutoxy silane of 3-sodium-thiolate propyl. Representative salts of formula II include but are not limited to dimethoxysilyl di (propyl lithium thiolate), dimethoxysilyl di (propyl potassium thiolate), dimethoxysilyldi (propyl sodium thiolate), dietoxysilyldi (propyl lithium thiolate), dietoxysilyl di (thiolate propyl potassium), dietixisilildi (propyl sodium thiolate) dibutoxisilildi (propyl lithium thiolate), dibutoxisilildi (propyl potassium thiolate), dibutoxisilildi (propyl sodium thiolate), methoxyethoxysilyldi (propyl lithium thiolate), methoxyethoxysilyldi (propyl potassium thiolate) and methoxyethoxysilyldi (propyl sodium thiolate). The salts of the formulas I and II can be prepared by reacting a mercaptoalkyltrialkoxysilane with NaH, KH or LiH. A representative example of this mercaptoalkyltrialkoxysilane is 3-mercaptopropyltriethoxysilane which can be obtained commercially from Hüls America Inc under the designation Dynasylan ™ 3201. The molar ratio of the mercaptoalkyltrialkoxysilane compound to NaH, KH or LiH can vary from .5: 2 to 2 :. 5. Preferably, the molar ratio varies from 1: 1 to 2: 2. The reaction is usually carried out in the presence of an appropriate solvent. The main criterion is to use a solvent that does not react with the starting materials or the final product. Representative organic solvents include chloroform, dichloromethane, carbon tetrachloride, hexane, heptane, cyclohexane, xylene, benzene, toluene, aliphatic and cycloaliphatic alcohols. Preferably, the water is avoided to prevent reaction with the Si-H and the siloxy groups of the compounds. The salts of the formula I can also be prepared by reacting a trialkoxysilanethiol with a lithium alkyl, potassium alkyl or sodium alkyl. The salts of the formulas I and II used in the present invention can be added to the rubber by any conventional technique such as in a mill or in a Banbury mixer. The amount of the salts of the formulas I and II can vary widely depending on the type of rubber and other compounds present in the vulcanizable composition. In general, the amount of the salts of the formulas I and II are used within the range of about .05 to about 10.0 phr with a scale of from I to about 5.0 phr being preferred. The salts of the formulas I or II are preferably added in the non-productive step with the silica and the organosilicon coupling agent containing optional sulfur. For ease of handling, the salts of the formula I and of the formula II can be used per se or can be deposited in appropriate carriers. Examples of carriers that can be used in the present invention include silica, carbon black, alumina silicates, alumina, clay, kieselguhr, cellulose, silica gel, and calcium silicate. The rubber compositions should contain a sufficient amount of silica and carbon black. If used, to contribute to a reasonably high module and high breaking strength. The silica filler or filler material can be added in amounts ranging from 10 to 250 phr. Preferably, the silica is present in an amount ranging from 15 to 80 phr. If carbon black is also present, the amount of carbon black if used may vary. Generally speaking, the amount of carbon black will vary from 0 to 80 phr. Preferably, the amount of carbon black will vary from 0 to 40 phr. It should be noted that the silica coupler can be used together with the carbon black, namely pre-mix with the carbon black before the addition to the rubber composition, and this carbon black must be included in the aforementioned amount of black of carbon for the formulation of the rubber composition. When the rubber composition contains both silica and carbon black, the weight ratio of silica to carbon black may vary. For example, the weight ratio can be as low as 1: 5 to a weight ratio of silica to carbon black of 30: 1. Preferably, the weight ratio of silica to carbon black varies from 1: 3 to 5: 1. The combined weight of silica and carbon black as mentioned herein, may be as low as about 30 phr, but preferably is from about 45 to about 90 phr. The siliceous pigments commonly used in rubber blending applications can be used as the silica in this invention, including pyrogenic siliceous pigments and precipitates (silica), even though precipitated silicas are preferred. The preferred siliceous pigments used in this invention are precipitated silicas such as, for example, those obtained by the acidification of a soluble silicate, e.g., sodium silicate. These silicas could be characterized, for example, by having a BET surface area as measured using nitrogen gas, preferably within the range of about 40 to about 600, and more usually within the range of about 50 to about 300. square meters per gram. The method for measuring the surface area of BET is described in Journal of the American Chemical Society, Volume 60, page 304 (1930). The silica may be typically characterized in that it has a dibutyl phthalate (DBP) absorption value within the range of about 100 to about 400, and more usually of about 150 to about 300. The silica could be expected to have an average final particle size , for example, within the range of 0.01 to 0.05 micron as determined by the electron microscope, even though the silica particles may still be of a smaller or possibly larger size.

The various commercially available silicas can be considered for use in the invention such as only for example herein, and without limitation, silicas commercially available from PPG Industries, under the trademark Hi-Sil with designations 210, 243, etc .; silicas obtainable from Rhone-Poulenc, with, for example, designations of Z1165MP and Z165GR and silicas obtainable from Degussa AG with, for example, designations VN2 and VN3, etc. The salts of formulas I and II function as a silica coupling agent. They can be used alone and / or in combination with an organosilicon compound containing symmetrical sulfur. Examples of suitable sulfur-containing organosilicon compounds are of the formula: Z-Alc-Snn-Alc-Z (III) where Z is selected from the group consisting of R4 R R5 I I I If R4 Yes R5 If R R5, R5 and RI wherein R4 is an alkyl group of 1 to 4 carbon atoms, cyclohexyl or phenyl; R ^ is alkoxy of 1 to 8 carbon atoms, or cycloalkoxy of 5 to 8 carbon atoms; Ale is a divalent hydrocarbon of 1 to 18 carbon atoms and n is an integer of 2 to 8. Specific examples of organosilicon compounds containing sulfur and which can be used in accordance with the present invention include: 3, 3'-bis ( trimethoxysilylpropyl) disufluro, 3,3'-bis (triethoxysilylpropyl) tetrasulfide, 3,3'-bis (triethoxysilylpropyl) octasulfide, 3'3'-bis (trimethoxysilylpropyl) tetrasulfide, 2,2'-bis (triethoxysilylethyl) tetrasulfide, 3, 3'-bis (trimethoxysilylpropyl) trisulfide, 3,3'-bis (triethoxysilylpropyl) trisulfide, 3,3'-bis (tributoxysilylpropyl) disulfide, 3,3'-bis (trimethoxysilylpropyl) hexasulfide, 3,3'-bis (trimethoxysilylpropyl) ) octasulfide, 3'3'-bis (trioctoxysilylpropyl) tetrasulfide 3'3'-bis (trihexoxysilylpropyl) disulfide, 3,3'-bis (tri-2"-ethylhexoxysilylpropyl) trisulfide, 3,3'-bis (triisooctoxysilylpropyl) tetrasulfide , 3,3 '-bis (tri-t-butoxysilylpropyl) disulfide, 2,2'-bis (methoxy diethoxy silylethyl) tetrasul furo, 2,2'-bis (tripropoxysilylethyl) pentasulfide, 3,3'-bis (tricyclonexosilylpropyl) tetrasulfide, 3,3'-bis (tricyclopentoxysilylpropyl) trisulfide, 2,2'-bis (tri-2"-methylcyclohexoxysilylethyl) tetrasulfide , bis (trimethoxysilylmethyl) tetrasulfide, 3-methoxy ethoxy-propoxysilyl 3'-diethoxybutoxysilylpropyltetrasulfide, 2,2'-bis (dimethylmethoxysilylethyl) disulfide, 2,2'-bis (dimethyl-sec.butoxysilylethyl) trisulfide, 3,3'- bis- (methylbutylethoxysilylpropyl) tetrisulfide, 3,3'-bis (di-t-butylmethoxysilylpropyl tetrasulfide, 2,2'-bis (phenylmethylmethoxylethyl) trisulfide, 3,3'-bis (diphenyl) isopropoxysilylpropyl) tetrasulfide, 3, 3 '- bis (diphenyl cyclohexoxysilylpropyl) disulfide, 3,3'-bis (dimethyl-ethylmercaptosilylpropyl) tetrasulfide, 2,2'-bis (methyl dimethoxysilylethyl) trisulfide, 2,2'-bis (methyl ethoxyprop)? xyrylethyl) tetrasulfide, 3,3 '-bis (diethylmethoxysilylpropyl) tetrasulfide, 3,3'-bis (ethyl di-sec.butoxysilylpropyl) disulfide, 3,3'-bis (propyl-diethoxysilylpropane) pil) disulfide, 3, 3'-bis (butyl-dimethoxysilylpropyl) trisulfide, 3,3'-bis (phenyl-dimethoxysilylpropyl) tetrasulfide, 3-phenyl-ethoxybutoxysilyl-3'-trimethoxysilylpropyl tetrasulfide, 4,4'-bis (trimethoxysilylbutyl) ) tetrasulfide, 6,6'-bis (triethoxysilylhexyl) tetrasulfide, 12,12'-bis (triisopropoxysilyldodecyl) disulfide, 18,18'-bis (trimethoxysilyloctadecyl) tetrasulfide, 18,18'-bis (tripropoxysilyloctadecenyl) tetrasulfide, 4.4 '-bis (trimethoxysilyl-buten-2-yl) tetrasulfide, 4,4'-bis (trimethoxysilylcyclohexylene) tetrasulfide, 5,5'-bis (dimethoxymethylsilylpentyl) trisulfide, 3,3'-bis (trimethoxysilyl-2-methylpropyl) tetrasulfide , 3,3'-bis (dimethoxyphenylsilyl-2-methylpropyl) disulfide. Preferred sulfur-containing organosilicon compounds are the 3,3'-bis (trimethoxy or triethoxysilylpropyl) sulfides. The especially preferred compound is 3, 3'-bis (triethoxysilylpropyl) tetrasulfide. Therefore, as regards formula III, preferably Z is If R; wherein R ^ is an alkoxy. from 2 to 4 carbon atoms, with 2 carbon atoms being particularly preferred; Ale is a divalent hydrocarbon of 2 to 4 carbon atoms with 3 carbon atoms being particularly preferred, and n is an integer of 3 to 5 with 4 being particularly preferred.

The amount of the sulfur-containing organosilicon compound of the formula III in a rubber composition will vary depending on the level of silica used. Generally speaking, the amount of the compound of formula III will vary from .00 to 1.0 part by weight per part by weight of silica. Preferably, the amount will vary from .00 to 0.4 part by weight per part by weight of silica. It will be readily understood by those skilled in the art that the rubber composition would be mixed by methods generally known in the rubber mixing field, such as the mixing of various constituents vulcanizable with sulfur with various commonly used additive materials such as for example sulfur donors, curing aids such as activators and retarders and processing additives, such as oils, resins including tackifying resins and plasticizers, fillers or fillers, pigments, fatty acid, zinc oxide, waxes, antioxidants and antiozonants and peptization agents. As is known to those skilled in the art, depending on the use to which the vulcanizable material with sulfur and vulcanized with sulfur (rubbers) is intended, the aforementioned additives are commonly selected and used in conventional amounts. Typical amounts of carbon black (s), of the type of reinforcement for this invention, if used, are noted herein. Representative examples of sulfur donors include elemental sulfur (free sulfur), an amine disulfide, polymeric polysulfide, and sulfur olefin adducts. Preferably, the sulfur vulcanization agent is elemental sulfur. The sulfur vulcanization agent can be used in an amount ranging from 0.5 to 8 phr, with a scale of 1.5 to 6 phr being preferred. Typical amounts of tackifying resins if used comprise from about 0.5 to about 10 phr, usually from about 1 to about 5 phr. Typical amounts of processing aids comprise from about 1 to about 50 phr. These processing aids may include, for example, aromatic, naphthenic and / or paraffinic processing oils. Typical amounts of antioxidants comprise from about 1 to about 5 phr. Representative antioxidants, for example, may be diphenyl-p-phenylenediamine and others, such as, for example, those disclosed in Vanderbilt Rubber Handbook (1978), pages 344-346. Typical amounts of antiozonants comprise from about 1 to 5 phr. Typical amounts of fatty acids if used, which may include stearic acid comprise from about 0.5 to about 3 phr. Typical amounts of zinc oxide comprise from about 2 to about 5 phr. Typical amounts of waxes comprise from about 1 to about 5 phr. Frequently microcrystalline waxes are used. Typical amounts of peptizers comprise from about 0.1 to about 1 phr. Typical peptizers, for example, may be pentachlorothiophenol disulfide and dibenzamidodiphenyl. In one aspect of the present invention, the rubber composition vulcanizable with sulfur, then cured or vulcanized with sulfur. Accelerators are used to control the time and / or temperature required for vulcanization and to improve the properties of the vulcanized material. In one embodiment, a single accelerator system, ie, a primary accelerator, can be used. The primary accelerator (s) can be used in total amounts ranging from 0.5 to about 4, preferably from about 0.8 to about 1.5, phr. In another embodiment, combinations of a primary and a secondary accelerator could be used with the secondary accelerator being used in minor amounts such as from about 0.05 to about 3 phr, in order to activate and improve the properties of the vulcanized material. The combinations of these accelerators could be expected to produce a synergistic effect on the final properties and are better than those produced by the use of any single accelerator. In addition, delayed action accelerators which are not affected by normal processing temperatures can be used but produce a satisfactory cure at regular vulcanization temperatures. Vulcanization retarders could also be used. The appropriate types of accelerators that can be used in the present invention are amines, disulfides, guanidines, thioureas, thiazoles, thiouramyls, sulfenamides, dithiocarbamates and xanthates. Preferably, the primary accelerator is a sulfenamide. If a second accelerator is used, the secondary accelerator is preferably a guanidine, dithiocarbamate or a thiouramyl compound. The mixing of the rubber composition can be achieved by methods known to those skilled in the rubber mixing art. For example, the ingredients are typically mixed in at least two stages, namely, at least one non-productive step followed by a productive mixing step. Final curatives including sulfur vulcanization agents are typically mixed in the final stage which is conventionally referred to as the "productive" mixing step where mixing typically occurs at a temperature or final temperature lower than the mixing temperature (s) that in the stage (s) of non-productive mixing. Rubber, silica, salt of formula I and II and carbon black, if used, are mixed in one or more non-productive mixing stages. The terms "non-productive" and "productive" mixing stages are well known to those skilled in the rubber mixing art. The vulcanizable rubber composition with sulfur containing the salt of the formulas I and II the vulcanizable rubber generally at least part of the silica, as well as the organosilicon compound containing sulfur, if used, must be subjected to a mixing step thermomechanical The thermomechanical mixing step usually comprises a mechanical treatment in a mixer or extrusion apparatus for an appropriate period of time in order to produce a rubber temperature of between 140 ° C and 190 ° C. The proper duration of the thermomechanical treatment varies as a function of the operating conditions and the volume and nature of the components. For example, the thermomechanical treatment can be from 1 to 20 minutes. The vulcanization of the rubber composition of the present invention is generally carried out at conventional temperatures ranging from about 100 ° C to 200 ° C. Preferably, the vulcanization is carried out at temperatures ranging from about 110 ° C to 180 ° C. Any of the usual vulcanization processes such as heating in a press or mold, heating with superheated steam or hot air or in a salt bath can be used. During the vulcanization of the composition vulcanized with sulfur, the rubber composition of this invention can be used for various objects. For example, the rubber composition vulcanized with sulfur can be in the form of a rim, a belt or a hose. In case of a tire, the rim can be used for several components. These rims can be made, shaped, molded and cured by various methods that are known and will be readily apparent to those skilled in the art. Preferably, the rubber composition is used as the tread surface of a rim. As you can see, the rim can be a rim for a passenger car, a tire for airplanes, a rim for a truck or the like. Preferably, the rim is a rim for a passenger car. The rim can also be a radial or bias rim, the radial rim being preferred. While certain embodiments and representative details have been shown for the purpose of illustrating the invention, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit or scope of the invention.

Claims (10)

1. - - CLAIMS: A compound is characterized by the formula Rl R < Yes _ (CH2 _). CH2 R- ' wherein R 1, R 2 and R 3 are independently selected from alkoxy radicals having from 1 to 8 carbon atoms, x is 0 or an integer from 1 to 10; and Y is Li, K or Na.
2. 2. A method for processing a silica loaded rubber composition which is characterized by (i) 100 parts by weight of at least one sulfur vulcanizable elastomer selected from conjugated diene homopolymers and copolymers and copolymers of at least one conjugated diene and an aromatic vinyl compound; (ii) 10 to 250 phr of silica precipitated into particles; (iii) from .05 to 10 phr of a compound of the formula R R Yes _ (_ CH2 _) _ x CH2 R3 wherein R 1, R 2 and R 3 are independently selected from alkoxy radicals having from 1 to 8 carbon atoms, x is 0 or an integer from 1 to 10; and Y is Li, K or Na.
3. 3. The method according to claim 2, characterized in that the composition of - - Silica-laden rubber is mixed thermomechanically at a rubber temperature within the range of 140 ° C to 190 ° C, during a mixing time of 1 to 20 minutes.
4. 4. The method according to claim 2, characterized in that the elastomer contains a functional group reactive with the compound of the formula I or II, the reactive group is selected from the group consisting of Cl, Br ,, -SCN and alkoxy.
5. 5. A rubber composition vulcanizable with sulfur, characterized by an elastomer containing olefinic unsaturation, silica and a compound of the formula Rl R Yes _ (_ CH2 _). -x CH2 R R II wherein R1, R2 and R3 are independently selected from alkoxy radicals having from 1 to 8 carbon atoms, x is 0 or an integer from 1 to 10; and Y is Li, K or Na.
6. The composition according to claim 5, characterized in that the composition is thermomechanically mixed at a rubber temperature within the range of 140 ° C to 190 ° C for a total mixing time of 1 to 20 minutes.
7. 7. The composition according to claim 5, characterized in that the elastomer contains a functional group reactive with the compound of formula I or II, the reactive group is selected from the group consisting of Cl, Br, -SCN and alkoxy.
8. 8. A vulcanized sulfur rubber composition which is characterized in that it is prepared by heating the composition of claim 4, to a temperature ranging from 100 ° C to 200 ° C, in the presence of a sulfur vulcanizing agent.
9. 9. The vulcanized sulfur rubber composition of claim 8 is characterized as being in the form of a rim, a belt or a hose.
10. 10. A rim having a rolling surface, characterized by the composition of claim 8.