MXPA99008977A - Preparation of reinforced rubber with starch and its use in plain - Google Patents

Abstract

The present invention relates to the preparation of a rubber composition containing, reinforcements of starch / plasticizer compound, together with at least one additional reinforcing filler, through the use of a combination of a mixed organosilane disulfide compound with a rubber composition in a mixing stage, non-productive, preparation or in various mixing stages, nonproductive preparation followed by the addition of an organosilane polysulfide compound in a subsequent productive mixing step. The invention further relates to the resulting rubber composition or use thereof in rubber products including rubber

Description

PREPARATION OF REINFORCED RUBBER WITH STARCH AND USE IN TIRE TIES FIELD OF THE INVENTION This invention relates to the preparation of rubber compositions containing a starch / plasticizer composite reinforcement, together with at least one additional reinforcing filler, and a disulfide compound. of aggregated organosilane in a non-productive mixing step or in several non-productive mixing steps and followed by the mixing of an organosilane polysulfide compound in a subsequent, productive mixing step. The invention also relates to the preparation of rubber compositions and in particular tires having at least one component, such as, for example, a floor of said compositions. BACKGROUND OF THE INVENTION Starch has sometimes been suggested for use in elastomer compositions for various purposes including tires, particularly a starch / plasticizer compound. See, for example, U.S. Patent No. 5,672,639. Said starch compounds can be used in combination with various other fillers, particularly reinforcing fillers for elastomers such as, for example, carbon black, silica, vulcanized rubber particles, short polymer fibers, clay, mica, talc, titanium dioxide and stone limestone. Carbon black and / or silica, particularly precipitated silica, may be preferred. Such short fibers can be, for example, cellulose fibers, aramid, nylon, aramid, polyester and carbon composition. U.S. Patent Nos. 5,403,923; 5,374,671; 5,258,430 and 4,900,361, for example, present a preparation and use of various starch materials. As mentioned in the aforementioned U.S. Patent No. 5,672,639, starch is typically represented in the form of a carbohydrate polymer having repeating units of a-ilose (anhydroglucopyranose units linked by glycosidic bonds) and amylopectin, a branched-chain structure , well known by experts in the field. Typically, the starch may be composed of about 25% amylose and about 75% amylopectin. (The Condensed Chemical Dictionary, Ninth Edition (1977), revised by G.G. Hawley, published by Van Nostrand Reinhold Company, page 813). The starch may be reportedly a reserve polysaccharide in plants such as, for example, corn, potato, rice and wheat as typical commercial sources. While the starch may have been previously suggested for use in rubber products, the starch itself typically has a softening point of about 200 ° C or more, and is considered here as having relatively limited use in many rubber products. , primarily because the rubber compositions are normally processed by preliminary mixing of the rubber with various ingredients at temperatures in the range of about 140 ° C to about 170 ° C, usually at least about 160 ° C, and sometimes up to 180 ° C. , which is not a temperature high enough to cause effective fusion of the starch (with a softening temperature of at least about 200 ° C) and to cause efficient mixing with the rubber composition. As a result, the starch particles tend to remain in individual domains or granules, within the rubber composition instead of mixing more homogeneously. Thus, it is considered here that said softening point disadvantage has relatively severely limited the use of starch as a filler, particularly as a reinforcing filler for many rubber products. It is considered here that the use of a starch / plasticizer compound, or softening point significantly lower than the softening point of the starch can only allow the starch to be mixed and processed more easily in conventional elastomer processing equipment. Such compounds, as indicated in the aforementioned U.S. Patent No. 5,672,639, may be, for example, a starch and plasticizer compound. A silica coupler can be used in combination with said starch compound and with silica, such as precipitated silica, for the purpose of increasing the reinforcing capacity, as indicated in U.S. Patent No. 5,672,639 which has a reactive portion with the surface of the silica (i.e., silicon hydroxide) and the surface of the starch compound and another interactive portion with a sulfur-curable elastomer. Coupling agents such as for example organosilane polysulfide having an average of 3.5 to 4 sulfur atoms in their polysulphide bridge have been employed for the coupling of precipitated silica with elastomers. Examples of said organosilane polysulfide is bis- (3-triethoxysilylpropyl) polysulfide with an average of about 3.8 sulfur atoms in its polysulphide bridge. It is stated that said polysulfide can be a sulfur donor, by releasing free sulfur during a typical high-cut mixing of a rubber composition at an elevated temperature, such as at temperatures of 100 ° C and above, depending on It forms the polysulfide used and the temperature and time of mixing. The small amount of free sulfur released is then available to be combined with a diene-based elastomer and / or possibly partially vulcanize a diene-based elastomer. However, it is considered here that a mixture of organosilane polysulfide, which is primarily a disulfide having an average of about 2.6 or fewer sulfur atoms in its polysulfide bridge, is not normally a good sulfur donor under such mixing conditions, due to the relatively strong sulfur-sulfur bonds typical of an organosilane disulfide - as compared to an organosilane polysulfide with an average of at least 3.5 sulfur atoms in its polysulfide bridge. Accordingly, it is considered here that, for an organosilane polysulfide containing an average of less than 2.8 and particularly within a range of about 2 to about 2.6 sulfur atoms in its polysulfide bridge, the release of free sulfur, if which exists, occurs at a relatively slower speed during a high cut rubber mixing stage, even when blending is carried out at a temperature within a range of about 150 to about 185 ° C depending on the overall mixing conditions, including the same mixing time. It is also taught that bis- (3-triethoxysilylpropyl) disulfide, such as a variety of organosilane disulfide, is useful in vulcanizable sulfur-containing elastomer compositions containing silica, even as a high purity form of said disulfide in, for example. , U.S. Patent No. 4,042,550 and German Patent Publication DT 2,360,471. However, it is considered here that said disulfide does not readily liberate free sulfur generally in said aforementioned rubber / silica / coupler mixing operation. For examples of organosilane polysulfides for use as silica couplers, see U.S. Patent Nos. 4,076,550; 4,704,414; and 3,873,489. For examples of organosilane disulfides added in a preparative, non-productive rubber composition mixing step, together with a small amount of free sulfur, see U.S. Patent Nos. 4,076,550; 5,580,919 and 5,674,932. In practice, elastomeric products vulcanized with sulfur are typically prepared by the thermomechanical rubber mixture and various ingredients step by step, sequentially, followed by the formation and curing of the rubber compound to form a vulcanized product. First for the aforementioned rubber mixture and various ingredients, typically excluding free sulfur and sulfur vulcanization accelerators, the elastomer or the elastomers and various rubber compounding ingredients are typically mixed in at least one stage and usually at least two. sequential thermomechanical mixing stages, of suitable mixer preparation, usually internal rubber mixers. Said preparation mixture is often referred to as "non-productive mixing" or "non-productive mixing steps or steps". Said preparative mixture is usually carried out at temperatures within a range of about 140 ° C to 190 ° C and more frequently within a range of 140 ° C or 150 ° C to about 185 ° C. After this step of sequential mixing, preparation or else these sequential mixing steps of preparation, free sulfur and vulcanization accelerators are mixed with sulfur, and possibly one or more additional ingredients with the rubber compound, or composition, in one step of final, productive mixing, typically at a temperature within a range of about 100 ° C to about 50 ° C, which is a temperature lower than the temperatures employed in the preparation mixing step or the aforementioned preparation mixing stages in order to avoid or reject a premature curing of the sulfur curable rubber which is sometimes referred to as "roasting", of the rubber composition. Said mixing steps, non-productive, sequential, and the subsequent productive mixing step are well known to those skilled in the art. By thermometallic mixing, we refer to the rubber compound, or rubber composition and rubber compounding ingredients that are mixed in a rubber mixture under high cutting conditions where it is heated in an autogenous manner, with a concomitant rise in the temperature, as a result of the mixing primarily due to the cut and associated friction within the rubber mixture in the rubber mixer. Said mixing process of thermo-mechanical and pre-associated rubber compound and related temperature rise aspects are well known to those skilled in the art of rubber preparation and mixing techniques. In practice, it is believed that the method indicated by the inventors of (1) adding an organosilane disulfide compound in a non-productive rubber composition mixing step, followed by (2) the subsequent addition of a polysulfide compound of organosilane with an average of 3.5 to 4.5 sulfur atoms in its polysulfide bridge together with a small amount of free sulfur in a productive rubber composition mixing step for a combination of starch compound and reinforced silicon-based rubber composition, particularly as a means for controlling the associated sulfur / elastomer interaction as well as the interaction with a silane / starch, as well as a crosslinking product of additional silane / filler compound _ (ie: silane / silica) created by the reaction of the organosilane compound with the reinforcement of starch compound and with the silica-based reinforcement in the stage or in the mixing stages of preparation, previ a (s), is novel and inventive taking into account the previous practice. In one aspect, it is believed that a decoupling of an initial silane / starch compound and a silane / silica reaction (through the organosilane component of the organosilane disulfide compound) and a subsequent release of free sulfur, and an additional silane reaction (through the subsequent addition of the organosilane polysulfide compound) to interact with the elastomer or the elastomers in a sequential rubber composition mixing process is accomplished by the use of a separate addition combination. and selective of an organosilane disulfide compound (I) and the subsequent addition of an organosilane (II) polysulfide compound followed by vulcanization of the rubber composition according to the process of this invention is a significant change compared to the previous practice. In the description of this invention, the organosilane disulfide compound is used to describe an organosilane polysulfide compound having an average of 2 to 2.6 sulfur atoms in its polysulfide bridge and the organosilane polysulfide compound is used for describe an organosilane polysulfide compound having an average of about 3.5 to about 4.5 sulfur atoms in its polysulfide bridge. The term "phr" as used herein, and in accordance with conventional practice, refers to "parts of a respective material per 100 parts by weight of rubber, or elastomer." In the description of this invention, the terms "rubber" and "elastomer", if used herein, may be used interchangeably, unless otherwise indicated. Terms such as "rubber composition", "composite rubber" and "rubber compound", if used herein, are used interchangeably to refer to "rubber that has been mixed with various ingredients and materials" and "rubber formation". "rubber compound" or "compound formation" can be used to refer to the "mixture of such materials". Such terms are well known to those skilled in the art of rubber blending or the technique of forming rubber compounds. A reference to "Tg" of elastomer, if used herein, refers to a "glass transition temperature" that can be determined by a differential scanning calorimeter at a rate of temperature increase of 10 ° C per minute. COMPENDIUM AND PRACTICE OF THE INVENTION In accordance with this invention, a process for preparing a rubber composition comprises the steps of: (A) mixing thermomechanically in at least one preparation mixing step and at a temperature within a range of about 150 At about 185 ° C and in the absence of addition of free sulfur (1) 100 parts by weight of at least one diene-based elastomer selected from conjugated diene homopolymers and conjugated diene copolymers and copolymers of at least one conjugated diene and aromatic vinyl compound, (2) from about 30 to about 100, alternatively from about 30 to about 90 phr of particulate filler consisting of (a) about 4 to about 90, alternatively about 5 to about 20% by weight of starch / plasticizer compound, (b) from about 96 to about 10, alternatively from about 95 to about 80% by weight of at least one additional reinforcing filler selected from carbon black, alumina and selected silica-based fillers within at least one of the following: precipitated silica, aluminosilicate, and modified carbon black containing hydroxide silicon on its surface; wherein said starch is formed of amylose units and amylopectin units in a ratio of about 15/85 to about 35/65 and has a softening point according to ASTM No. D1228 within a range of about 180 ° to about 220 ° C and wherein said starch / plasticizer compound has a softening point within a range from about 110 ° C to about 170 ° C according to ASTM No. D1228, and (3) from about 0.05 to about 20, alternatively, from about 0.05 to about 10 parts by weight per part by weight of said starch / plasticizer, alumina and silicon-based filler of at least one organosilane disulfide compound of the formula (I): (I) Z-Rl-Sn-Rl- Z followed by: B) mixing with them in a subsequent mixing step at a temperature within a range of about 100 ° C to about 130 ° C, of at least one organosilane polysulfide compound from the mule (II) and free sulfur; where the total addition of free sulfur and about 50% of the sulfur in the polysulfide bridge of said polysulfide sulfur donor is within a range of about 0.93 to about 4, alternatively within a range of about 0.93 to approximately 2.8 phr (II) Z-Rl-Sm-Rl-Z Where, n is a number within a range of 2 to approximately 6 and the average for n is within a range of approximately 2 to 2.6; Where n is a number from 2 to about 8 and the average for m is within a range of about 3.5 to about 4.5; Where Z is selected from a group consisting of: R2 R2 R3 II (Zl) Si- • R2 (Z2) YES-R3 (Z3) YES-R3 I R3 R3 and R3 where R2 may be identical or different and is selected individually within the group consisting of alkyl group having from 1 to 4 carbon atoms and phenyl, preferably methyl and ethyl radicals; R3 may be the same or different and is selected individually from the group consisting of alkyl groups having from 1 to 4 carbon atoms, phenyl groups, alkoxy having from 1 to 8 carbon atoms and cycloalkoxy groups having from 5 to 8 carbon atoms, preferably between methyl and ethyl groups; and R1 is selected from the group consisting of a substituted or unsubstituted alkyl group having a total of 1 to 18 carbon atoms and a substituted or unsubstituted aryl group having a total of 6 to 12 carbon atoms. In practice, between each mixing step, the rubber composition is allowed to cool to a temperature below about 40 ° C, such as, for example, within a range of about 40 ° C to about 20 ° C. In practice, the total mixing time for such preparation (non-productive) mixing steps may be within a range of from about 2 to about 20, alternately from about 4 to about 15 minutes and from about 1 to about 3 minutes to said subsequent step of mixing (productive). For said formula (I) the organosilane polysulfide compound is, primarily, an organosilane disulfide in the form of a mixture of organosilane polysulfide wherein at least 55, usually at least 65% of n is 2, and preferably of about 80 to about 100% of n is 2. For said formula (II), the organosilane polysulfide compound is a mixture of organosilane polysulfides in which at least 70% and preferably from about 80 to about 100% of m are finds within the range of about 3.5 to about 4.5. In one aspect, the organosilane polysulfide compound of the formula (II) has a property of releasing at least a portion of its sulfur at a temperature within a range of about 150 ° C to about 185 ° C. Particularly, it can be considered, according to the selection and quantity employed an organosilane polysulfide compound that the free sulfur released from said organosilane polysulfide compound (formula II) during the molding and curing of the rubber composition is at an elevated temperature within a range of about 140 ° C to about 185 ° C may for example be within a range of about 0.13 about 1 phr. A global philosophy of this invention is considered here in the sense of first promoting separately and selectively an initial silane reaction with the reinforcing fillers., including the starch / plasticizer compound, without significant premature release of free sulfur and then, subsequently, the promotion of both the release of free sulfur and an additional reaction of silane with the product of the first silane reaction. A particular benefit is observed in the sense that the prevention of a premature release of free sulfur allows a lower viscosity of the rubber composition even under the conditions of high severity mixing required for an optimization of filler dispersion and polymer-filler interaction. An additional benefit is a late combination of free sulfur generation together with a subsequent and additional silane reaction. This is achieved by manipulating the first batch of organosilane disulfide compound (I) with the elastomer or reinforcing elastomers and fillers, including the starch compound, followed by the subsequent and separate mixing of the organosilane polysulfide compound (II). ) with the rubber and the silane-filler network product. It is considered that this process is novel and is a significant change compared to the previous practice. In practice, an accumulation of viscosity of the rubber composition during its non-productive preparation mixing stage or its non-productive preparation mixing stages due to premature partial vulcanization caused by a release of free sulfur from the polysulfide is avoided. of organosilane (II) having an average of about 3.5 to about 4.5 sulfur atoms in its polysulfide bridge. However, the benefits of the reaction of the organosilane components of the organosilane disulfide compound (I) with the reinforcing fillers, including the starch / plasticizer compound, are still obtained. Subsequently, the subsequent addition of the organosilane polysulfide compound in the production step under mixing conditions at lower temperatures, and allowing the added organosilane polysulfide compound to help vulcanize the rubber composition both by the release of sulfur to the higher cure temperature and allowing the silane portion of the organosilane (II) polysulfide compound to interact with the organosilane / starch-plasticizer compound previously created and the organosilane / filler compound (ie the silane / silica and / or aluminosilicate silane points) or network of said compounds. This aspect of the present invention, as understood, is achieved by first employing an organosilane disulfide compound (I) having an active silane portion but not releasing appreciable amounts of free sulfur such that free sulfur is not released. during the preliminary non-productive mixing stage or the preliminary nonproductive mixing stages and in such a way that the sulfur can be separately added subsequently through the organosilane polysulfide compound (II) described below in the vulcanization of the rubber composition . In this way, the benefits of the initial and selective reaction of the silane portion of the organosilane disulfide compound with the starch compound and silica-based filler are preserved, but the release of free sulfur, and the interaction of additional silane is retarded. until after the initial preliminary nonproductive mixing step or initial preliminary nonproductive mixing steps at the highest mixing temperature and the subsequent productive mixing step at the lower mixing temperature and until the vulcanization of the rubber composition to the highest temperature. In an aspect of the invention, said process is provided where said preparation mixing is carried out in at least two sequential steps of thermomechanical mixing of which at least two of these mixing steps are carried out at a temperature within a range- from about 140 ° C to about 185 ° C, with intermediate cooling of the rubber composition between at least said mixing steps at a temperature below about 40 ° C. In accordance with the present invention, the rubber composition according to that prepared by the method of the present invention is provided. In accordance with the present invention, there is provided an article having at least one component of said rubber composition. According to said invention, a rim is provided having at least one component of said rubber composition. In accordance with the present invention, a tire having a floor of said rubber composition is provided, particularly where said tire floor is designed to be in contact with the ground. In one aspect, the prepared rubber composition is vulcanized in a suitable mold at an elevated temperature within a range of about 140 ° C to about 185 ° C or 190 ° C. Further, in accordance with the present invention the process comprises the additional steps of preparing an assembly of a vulcanizable rubber rim with sulfur with conformed floor of said rubber composition prepared in accordance with the process of this invention and vulcanizing the assembly to a temperature within a range of about 140 ° C to about 185 ° C to 190 ° C. Accordingly, the invention also contemplates a vulcanized tire prepared by said process. In the practice of this invention, the aforementioned starch is typically composed of amylose units and amylopectin units in a ratio of about 15/85 to about 35/65, alternatively in a ratio of about 20/80 to about 30/70 , and has a softening point in accordance with ASTM No. D1228 within a range of about 180 ° C to about 220 ° C; and the starch / plasticizer compound has a softening point within a range of about 110 ° C to about 170 ° C in accordance with ASTM No. D1228.-For the starch / plasticizer compound, in general, the weight ratio between starch and plasticizer is within a range of about 0.5 / 1 to about 4/1, alternatively from about 1/1 to about 2/1, insofar as the starch / plasticizer composition has the range of softening point required, and preferably, it can have a dry powder or extruded pellets, in free flow, before being mixed with the elastomer or the elastomers. In practice, it is desirable that the synthetic plasticizer itself be compatible with the starch, and that it have a softening point below the softening point of the starch in such a way as to cause the softening of the plasticizer / starch mixture to be less than the softening point. softening of starch alone. This phenomenon of mixtures of compatible polymers of different softening points having a softening point lower than the highest softening point of the individual polymer or of the individual polymers in the mixture is a well-known phenomenon on the part of those skilled in the art. . For the purposes of this invention, the effect of the plasticizer for the starch / plasticizer compound (which means a softening point of the minor compound - than the softening point of the starch), can be obtained through the use of a polymeric plasticizer, such as for example polyethylene vinyl alcohol with a softening point lower than 160 ° C. Other plasticizers, and mixtures thereof, are contemplated for use in this invention provided they have softening points below the softening point of the starch and preferably less than 160 ° C, which may be, for example, one or more copolymers and hydrolyzed copolymers thereof selected from ethylene-vinyl acetate copolymers having a molar content of vinyl acetate from about 5 to about 90, alternatively from about 20 to about 70%, ethylene-glycid acrylate copolymers and ethylene copolymers -maleic anhydride. In accordance with what is indicated herein, hydrolyzed forms of copolymers are also contemplated. For example, the corresponding ethylene-vinyl alcohol copolymers and the ethylene-acetate-vinyl alcohol terpolymers can be contemplated insofar as they have a softening point below the softening point of the starch and preferably less than 160 ° C. In general, the mixture of the starch and the plasticizer includes what is considered or believed to be relatively strong chemical and / or physical interactions between the starch and the plasticizer. Representative examples of synthetic plasticizers are, for example, polyethylene vinyl alcohol, cellulose acetate and diesters of dibasic organic acids, insofar as they have a softening point sufficiently below the softening point of the starch with which they are combined in such a way that the starch / plasticizer compound has the required softening point range. Preferably, the synthetic plasticizer is selected from at least one of the following: (poly) ethylene vinyl alcohol and cellulose acetate. For example, the aforementioned (poly) ethylene vinyl alcohol can be prepared by the polymerization of vinyl acetate to form a (poly) vinyl acetate which is then hydrolyzed (catalyzed by acid or base) to form the (poly) ethylene vinyl alcohol. Said reaction of vinyl acetate and hydrolyzing the resulting product is well known to those skilled in the art. For example, copolymers of vinyl alcohol / ethylene (molar ratio 60/40) in powder and in pellets can be obtained conventionally in different molecular weights and different crystallinity such as for example a molecular weight of about 11,700 with an average particle size "of about 11.5 microns or a molecular weight (weight average) of about 60,000 with an average particle diameter of less than 50 microns Several mixtures of starch and copolymers of ethylene vinyl alcohol can be prepared in accordance with well-known mixing procedures by those skilled in the art. For example, you can use a procedure according to what is stated in the published Bastioli patent, Bellotti and Del Trediu entitled "A Polymer Composition Including Destructured Starch An Ethylene Copolymer", North American patent number 5,403,374. Other plasticizers can be prepared, for example, to the extent that they have the appropriate glass transition temperature and the appropriate starch compatibility requirements, by reacting one or more appropriate organic dibasic acids with aromatic diol (s) (s). ) or aliphatic (s) in a reaction that can sometimes be known as an "esterification condensation reaction". Said esterification reactions are well known to those skilled in the art. A particular feature of this invention is the use of the starch compound as a significant component of elastomer reinforcement in combination with the prescribed sequential addition of the organosilane disulfide compound (I) and followed by the organosilane (II) polysulfide compound in the preparation of a rubber composition and particularly a vulcanized tire floor. In one aspect, it was observed that, when an inclusion of the starch compound is provided in an elastomer composition when the sequential, double organosilane polysulfide addition process of this invention is employed, the vulcanized hardness of the elastomer was lowered while its modulus 300% remained relatively high.

As a consequence it was observed, in an evaluation of the elastomer composition as illustrated in the present examples, that the wet traction of a rim floor can be improved without significantly degrading a rim handling property where a compound is employed. of starch / plasticizer together with the double, sequential and selective addition of the compound (I) of organosilane disulfide and the subsequent addition of the organosilane polysulfide compound (II). It is believed that in the practice of using the starch compound for a partial replacement for silica reinforcement in the practice of the process of this invention is novel and represents a major change in relation to the prior practice. In one aspect of the invention, optionally, a total of about 0.05 to about 5 phr of at least one alkyl alkoxysilane can be thermomechanically mixed in the preparation mixing step or the preparation mixing steps, particularly when said alkyl silane has the formula: R'-Si- (0R) 3, where R is a methyl, ethyl, propyl or isopropyl radical and R'is a saturated alkyl radical having from 1 to 18 carbon atoms, or an aryl or substituted aryl radical or substituted alkyl having from 6 to 12 carbon atoms. Said substituted aryl or aryl radicals may be, for example, benzyl, phenyl, tolyl, methyltolyl, and alpha methyl ethylol radicals. An object of the alkylalkoxy silane is, for example, to improve the filler incorporation and the compound aging. Representative examples of alkyl silanes are, for example, without limitation, propyltriethoxysilane, methyltriethoxysilane, hexadecyltriethoxysilane and octadecyltriethoxysilane. In practice, as mentioned above, the organosilane polysulfide compound of the formula (II) is added in the lower temperature productive mixing step, which subsequently releases the free sulfur at the highest temperature experienced during molding and curing. of the resultant rubber composition in which it is contemplated that the silane component of the organosilane (II) polysulfide compound formula will react with the previously formed silane-silicon and silane / starch composite network. While a real calculation may be necessary on an individual basis, according to the number of sulfur atoms in the sulfur bridge as well as according to other factors, the amount of free sulfur to be added in the productive mixing stage, plus the amount of free sulfur released through the organosilane polysulfide compound of the formula (II) is contemplated within a range of about 0.13 to about 4, alternatively from about 0.13 to about 2.8 phr. This considers that from about 40 to about 60% of the sulfur of the organosilane polysulfide compound of the formula (II) is released in the form of free sulfur during the curing step. In practice, it is preferred that at least 1 phr of free sulfur and at least one phr of the organosilane polysulfide compound of the formula (TI) are added in the productive mixing step. Vulcanization accelerators are conventionally added in the stage of productive mixing. Some vulcanization accelerators are not conventionally considered as sulfur donors in the sense of releasing free sulfur; it is noted that they may be, for example, of the benzothiazole type, alkylthiuram disulfide, guanidine derivatives and thiocarbamates. Representatives of such accelerators are, for example, not limited to, mercapto benzothiazole, tetramethyl thiuram disulfide, benzothiazole disulfide, diphenylguanidine, zinc dithiocarbamate, alkylphenol disulfide, zinc butylxanthate, N-dicyclohexyl-2-benzothiazole sulfenamide, N- cycloexi1-2-benzothiazolesulfenamide, N-oxydiethylenebenzothiazole-2-sulfenamide, N, N diphenylthiourea, dithiocarbamyl sulfenamide, N, N diisopropylbezothiazole-2-sulfenamide, zinc-2-mercaptotoluimidazole, dithiobis (N-methyl piperazine), dithiobis (N beta hydroxy ethyl piperazine) and dithiobis (dibenzylamine). Such materials are well known as sulfur vulcanization accelerators for vulcanizable elastomers with sulfur by persons having knowledge of the rubber forming technique. If desired, even when not preferred in the practice of this invention, additional conventional sulfur donors can be added in the final, productive mixing step, to the extent that the total amount of free sulfur that is added in the step Productive mixing and the free sulfur released in the curing step from the aforementioned organosilane polysulfide and the sulfur donor of this paragraph is within a range from about 0.13 to about 2.8 phr. Representatives of such additional sulfur donors are, for example, derivative of thiuram and morpholine. Representative of such materials are, for example, dimorpholine disulfide, dimorpholine tetrasulfide, tetramethyl thiuram tetrasulfide, benzthiazil-2 dithiomorpholide, N-dithomorpholide, thioplast, dipentamethylenethiurahexasulfide, as well as disulfidecaprolactam. Such materials are well known as sulfur donors by those skilled in the art of rubber formation. To the extent that such sulfur donors are added in the productive mixing stage, the amount of free sulfur added is correspondingly reduced. For the filler reinforcement of this invention, there are contemplated silica-based pigments that can be used in combination with carbon black. In one aspect of the invention, it is preferred that the silica-based filler be precipitated silica. In another aspect of the invention, it is preferred that the silica-based filler be carbon black having silicon hydroxide on its external surface. In a further aspect of the invention, it is preferred that the silica-based filler be an inosilicate alu as a coprecipitated combination of silica and aluminum with an aluminum content in the range of about 0.05 to about 10% of said silica filler compound. aluminum. The carbon black having silicon hydroxide on its surface can be prepared, for example, by co-moistening a silane organ and oil at an elevated temperature. In practice, the reinforcing filler may consist of from about 15 to about 95% by weight of precipitated silica, alumina, aluminosilicate and / or carbon black containing silicon hydroxide on its surface and, therefore, from about 5 to about 85% by weight of carbon black.

When desired for the rubber composition, which contains both a starch and filler compound based on alumina and / or silica, such as for example precipitated silica, aluminosilicates and / or carbon black having silicon hydroxide on its surface, and also It is often preferable that the weight ratio between said filler or said fillers based on silica and the carbon black be at least 1.1 / 1 and often at least 3/1, even up to 10. / 1 and, therefore, within a range of about 1.1 / 1 to about 30/1. For the aforementioned organosilane disulfide of the formula (II) and the organosilane polysulfide of the formula (II), representative R 2 radicals are alkyl radicals and representative R 1 radicals are selected from alkaryl, phenyl and haloaryl radicals. Accordingly, in one aspect of the invention, the radicals R 2 and R 1 are mutually exclusive. Preferably such radicals are alkyl radicals. Representative examples of such alkyl radicals are methyl, ethyl, N-propyl and N-decyl radicals, with the N-propyl radical being preferred. Representative examples of aralkyl radicals are benzyl and alpha, alpha dimethylbenzyl radicals are preferred if 3 radicals are to be employed.

Representative examples of alkaryl radicals are p-tolyl and p-nonylphenol radicals if such radicals are to be used. A representative example of a haloaryl radical is a p-chlorophenol radical if such a radical is to be used. Representative examples of organosilane polysulfides of the compounds of formula (II) are, for example, without limitation, bis (3-trimethoxysilylpropyl) tetrasulfide bis (3-trimethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylethyltolylene) trisulfide and bis (3-triethoxysilylethyltolylene) tetrasulfide). Representative examples of organosilane disulfide of the compound of the formula (I) are, for example: 2,2'-bis (trimethoxysilylethyl) disulfide; 3, 3'-bis (trimethoxysilylpropyl) disulfide; 3, 3'-bis (triethoxysilylpropyl) disulfide; 2, 2'-bis (triethoxysilylethyl) disulfide; 2, 2'-bis disulfide (tripropoxysilylethyl); 2, 2'-bis (tri-sec.butoxysilylethyl) disulfide; 2, 2'-bis (tri-t-butoxyethyl) disulfide; 2, 2'-bis (triethoxysilylethyltolylene) disulfide; 2, 2'-bis (trimethoxysilylethyltolylene) disulfide; 3, 3'-bis (triisopropoxypropyl) disulfide; 3, 3'-bis (trioctoxypropril) disulfide; 2, 2'-bis (2'-ethylhexoxysilylethyl) disulfide; 2, 2'-bis (dimethoxy ethoxysilylethyl) disulfide; 3, 3'-bis (methoxyethoxypropoxysilylpropyl) disulfide; 3, 3'-bis (methoxy dimethylsilylpropyl) disulfide; 3, 3'-bis (cyclohexoxy dimethylsilylpropyl) disulfide; 4,4'-bis (trimethoxysilylbutyl) disulfide; 3, 3'-bis (trimethoxysilyl-3-methylpropyl) disulfide; 3, 3'-bis disulfide (tripropoxysilyl-3-methylpropyl); 3, 3'-bis (dimethoxymethylsilyl-3-ethylpropyl) disulfide; 3, 3'-bis (trimethoxysilyl-2-methylpropyl) disulfide 3,3'-bis (dimethoxyphenylsilyl-2-methylpropyl) disulfide; 3, 3'-bis (trimethoxysilylcyclohexyl) disulfide; 12, 12'-bis (trimethoxysilyldodecyl) disulfide; 12, 12'-bis (triethoxysilyldodecyl) disulfide; 18, 18'-bis (trimethoxysilyloctadecyl) disulfide; 18,18'-bis (methoxydimethylsilyloctadecyl) disulfide; 2,2'-bis (trimethoxysilyl-2-methylethyl) disulfide; 2, 2'-bis (triethoxysilyl-2-methylethyl) disulfide; 2, 2'-bis disulfide (tripropoxysilyl-2-methylethyl); and 2,2'-bis (trioctoxysilyl-2-methylethyl) disulfide. In practice, 3,3'-bis (triethoxysilylpropyl) disulfide which may also be represented as bis- (3-triethoxysilylpropyl) disulfide is preferred.

In the practice of this invention, as indicated above, the rubber composition consists of at least one diene-based elastomer, or rubber. Suitable conjugated dienes are isoprene and 1,3-butadiene and suitable vinyl aromatics are styrene and alpha-methylstyrene. Thus, it is considered that the elastomer is a sulfur-curable elastomer. Said diene or rubber based elastomer may be selected, for example, from at least one of cis-1-cis-cis-isoprene (natural and / or synthetic) rubber, and preferably natural rubber, styrene / butadiene copolymer rubber prepared by emulsion polymerization, styrene / butadiene rubber prepared by polymerization of organic solution, 1,4-polyisoprene rubber, isoprene / butadiene rubber, styrene / isoprene / butadiene terpolymer rubbers, 1,4-polybutadiene cis, vinyl polybutadiene rubber medium (from 35 to 50% vinyl), high vinyl polybutadiene rubber (from 50 to 75% vinyl), styrene / isoprene copolymers, styrene / butadiene / acrylonitrile terpolymer rubber prepared by emulsion polymerization and copolymer rubber butadiene / acrylonitrile. By E-SBR prepared by emulsion polymerization, it is understood that styrene and 1,3-butadiene are copolymerized as an aqueous emulsion. These are well known in the art. The bound styrene content may be several, for example, from about 5 to 50%.

The SBR prepared by solution polymerization (S-SBR) typically has a styrene content bound within a range of about 5 to about 50, from about 9 to about 36%. The S-SBR can be conveniently prepared, for example, by catalyzing the lithium organ in the presence of an organic hydrocarbon solvent. As indicated above, the precipitated silicas used in this invention are precipitated silicas such as, for example, those obtained by the acidification of a soluble silicate, for example sodium silicate. Said precipitated silicas are well known by persons having knowledge in the field. Likewise, as mentioned above, a contemplated variation of aluminosilicate is obtained by the coprecipitation of silica and aluminum. Said precipitated silicas can be characterized, for example, because they have a BET surface area, as measured using nitrogen gas, preferably within the range of about 40 to about 600, and more usually within a range of about 50 to about 300. square meters per degree. The BET method for the measurement of surface area is described in the Journal of the American Chemical Society, volume 60, page 304 (1930). The silica can also be typically characterized in that it has an absorption value of dibutyl phthalate (DBP) within a range of about 100 to about 350, and more usually within a range of about 150 to about 300 ml / 100 g. In addition, the silica, as well as the aforementioned alumina and aluminosilicate, may have a surface area of CTAB within a range of about 100 to about 220. The CTAB surface area is the external surface area in accordance with that evaluated by bromide. of cetyltrimethylammonium with a pH of 9. The method is described in ASTM D 3849 for adjustment and evaluation. The surface area of CTAB is a well-known means to characterize silica. The surface area of mercury / porosity is the specific surface area determined by mercury porosimetry. For a technique of this type, mercury penetrates the pores of the sample after heat treatment to remove volatile substances. Adjustment conditions can be adequately described as the use of a 100 mg sample; the removal of volatile agents for 2 hours at a temperature of 105 ° C and ambient atmospheric pressure; range of pressure measurement of ambient pressure at 2000 bar. This evaluation can be carried out in accordance with the method described by Winslow, Shapiro in the ASTM bulletin, page 39 (1959) or in accordance with DIN 66133. For an evaluation of this type, a 2000 CARLO porosimeter can be used. -BA The specific surface area of average mercury porosity for the precipitated silica should preferably be within a range of approximately 100 to 300 square meters / g. A more suitable pore size distribution for silica, alumina and aluminosilicate in accordance with said mercury evaluation is preferably the following: 5% or less of its pores have a diameter less than about 10 nm; 60 to 90% of its pores have a diameter of about 10 to about 100 nm; from 10 to 30% of its pores have a diameter of about 100 to about 100%; and from 5 to 20% of its pores have a diameter greater than about 1000 nm. The silica may have a final, average particle size, for example, within the range of 0.01 to 0.05 mire as determined by electron microscopy, even though the silica particles may be even smaller, or possibly larger, as to its size. Various commercially available silicas may be considered for use in this invention, for example, by way of example only and without limitation, silicas commercially available from PPG Industries under the trademark Hi-Sil with designations Hi-Sil 210, 243, etc.; silicas available from Rhone-Poulenc, for example, designation of Zeosil 1165MP, silicas available from Degussa GmbH, for example, designations VN2 and VN3, etc., and silicas commercially available from Huber having, for example, a designation of Hubersil 8745. alumina, for the purposes of this invention, is natural and synthetic aluminum oxide (A1203). In some cases, alumina has been used for that purpose either alone or in combination with silica. The term "alumina" can be described herein as "aluminum oxide or A1203". The use of alumina in rubber composition can be seen, for example, in U.S. Patent No. 5,116,886 and in European Patent Publication EPO 631,982 A2. It is recognized that alumina can be in various forms, ie, acid form, neutral form, and basic form. In general, it is considered here that the neutral form may be the preferred form. The aluminosilicates, for the purpose of this invention, can be used as natural materials or they can be prepared synthetically, particularly coprecipitated silica and aluminum. For example, see U.S. Patent No. 5,723,529. In general, the term "aluminosilicate" can be described as "natural or synthetic materials where the silicon atoms of a silicon dioxide are partially replaced or replaced, either manually or synthetically, by aluminum atoms". For example, from about 5 to about 90. Alternatively from about 10 to about 80% of silicon atoms of a silicon dioxide can be replaced, or substituted, naturally or synthetically, by aluminum atoms to provide an aluminosilicate. A process suitable for a preparation of this type can be described, for example, as by coprecipitation by adjusting the pH of a basic solution, or mixtures of silicate and aluminate also, for example, by means of a chemical reaction between Si02, or silanols on the surface of a silicon dioxide, and NaA102. For example, in a co-precipitation process of this type, the synthetic coprecipitated aluminosilicate can have from about 5 to about 95% of its surface composed of portions of silica and, correspondingly, from about 95 to about 5% of its composite surface of aluminum portions. Examples of aluminosilicates are, for example, muscovite, beryl, dichroite, sepiolite and kaolinite. Examples of synthetic aluminosilicates are, for example, zeolite and those which can be represented by formulas such as, for example, ((A1203) x (SiO2) and (H20) z); ((A1203) x. (Si02) y.MO); where M is magnesium or calcium. The use of aluminosilicates in rubber compositions can be illustrated, for example, in U.S. Patent No. 5,116,886, in European Patent Publication EPO 063,982 A2, Rubber Chem. Tech., Volume 50 page 606 (1988) and volume 60, page 84 (1983). It will be readily understood by those skilled in the art that the rubber composition can be shaped by methods generally known in the rubber forming art, such as, for example, by mixing the various sulfur-vulcanizable constituent rubbers with various commonly used additive materials such as for example, curing aids, such as sulfur, activators, retardants and accelerators, processing additives, such as oils, resins including tackifying resins, silica, and plasticizers, fillers, pigments, fatty acid, zinc oxide, waxes , antioxidants and antiozonants, peptizing agents and reinforcing materials such as, for example, carbon black. As those skilled in the art know, according to the intended use of the material vulcanizable with sulfur and vulcanized with sulfur (rubbers), the additives mentioned above are selected and frequently used in conventional amounts. Typical amounts of reinforcing type black (s) for this invention, if employed, are presented below. It will be noted that the silica coupler can be used in combination with a carbon black, ie, premixed with a carbon black prior to addition to the rubber composition, and that said carbon black must be included in the aforementioned amount. of carbon black for the formulation and composition of rubber. Typical amounts of tackifying resins, if employed, 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. Such 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 may be, for example, diphenyl-p-phenylenediamine and others such as, for example, those disclosed in The Vanderbilt Rubber Handbook (1978), pages 344-346. Typical amounts of antiozonants comprise from about 1 to about 5 phr. Typical amounts of fatty acids, if employed, 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 spheres 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 can be, for example, pentachlorothiophenol and dibenzamidodiphenyl disulfide. The vulcanization is carried out in the presence of a sulfur vulcanization agent. Examples of suitable sulfur vulcanization agents include, for example, elemental sulfur (free sulfur) or sulfur donor vulcanizing agents, for example, an amine disulfide, polymeric polysulfide or sulfur olefin adducts which are conventionally added in the final, productive rubber composition mixing stage. Preferably, in most cases, the sulfur vulcanization agent is elemental sulfur. As is known to those skilled in the art, sulfur vulcanization agents are used, or are added in the stage of productive mixing, in an amount that is within a range of about 0.4 to about 3 phr or, in some cases up to about 8 phr, usually ranging from about 1.5 to about 2.5, sometimes from 2 to 2.5. Accelerators are used to control the time and / or temperature required for vulcanization and to improve the properties of the vulcanized product. In one embodiment, a single accelerator system, ie, a primary accelerator, may be employed. Conventionally, and preferably, a primary accelerator or several primary accelerators are employed in total amounts ranging from about 0.5 to about 4, preferably from about 0.8 to about 1.5 phr. In another embodiment, combinations of a primary accelerator and a secondary accelerator can be employed, the secondary accelerator being used in minor amounts (from about 0.05 to about 3 phr) in order to activate and improve the properties of the vulcanized product. It can be expected that combinations of these accelerators will produce a synergistic effect on the final properties and will be relatively better than those produced by any of the accelerators alone. In addition, delayed action accelerators which are not affected by normal processing temperatures can be employed but produce a satisfactory cure at usual vulcanization temperatures. Vulcanization retardants can also be used. Suitable types of accelerators that can be employed in the present invention are amines, disulfides, guanidines, thiureas, tlazoles, thiurams, 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 thiuram compound.

The rubber composition of this invention can be used for various purposes. For example, it can be used for several rim compounds. Such tires can be constructed, formed, molded and cured by various methods that are known and will be apparent to those skilled in the art. The invention can be better understood with reference to the following examples in which the parts and percentages are given by weight unless otherwise indicated. EXAMPLE I Experiments, or samples, example 1, example 2 and example 3, vulcanizable rubber mixtures with sulfur containing starch / plasticizer compounds and precipitated silica reinforcement were prepared and reported here as experiments, or samples. Particularly in the case of Example 1 as a control, an organosilane tetrasulfide compound (II) is mixed, namely a bis- (3-ethoxysilylpropion) tetrasulfide compound, which has an average of about 3.8 sulfur atoms in its range. polysulphide bridge with the rubber composition in a mixing stage, non-productive, of preparation in an internal rubber mixer. Particularly, for example 2, also in some form as a control, an organosilane disulfide compound, bis- (3-ethoxysilylpropyl) disulfide of the formula (I), having an average of about 2.2 sulfur atoms in its polysulphide bridge with the rubber composition in a non-productive preparation mixing stage in the internal rubber mixer. Finally, and in accordance with this invention for example 3, an organosilane disulfide compound, bis- (3-ethoxysilylpropyl) disulfide of the formula (I) having an average of about 2.2 sulfur atoms in its bridge is mixed. of polysulphide with the rubber composition and reinforcement fillers in a non-productive preparation mixing step, after which in a subsequent stage of productive mixing, an organosilane tetrasulfide compound, bis- (3-) tetrasulfide, is mixed. ethoxysilylpropyl) of the formula (II), which has an average of about 3.8 sulfur atoms in its polysulphide bridge, as well as an amount of free sulfur and accelerator (s) of vulcanization with the rubber composition in a final, productive stage of mixing in an internal rubber mixer. Particularly, for Example 3 which is exemplary of this invention, 6.64 phr of the organosilane disulfide material of the formula (I) is added in the non-productive mixing step, of preparation, and an _phr of the organosilane polysulfide of the formula (II), and 1.4 phr of sulfur are added in the productive mixing stage. Therefore, for the productive mixing stage, the aggregate calculated sulfur (based on 50% of the sulfur atoms in the polysulfide bridge of the organosilane polysulfide of formula (II)) is 1.4 phr (free sulfur) plus 0.13 phr (from the polysulfide) to reach 1.53 phr.It will be noted that the actual sulfur may differ slightly from the calculated sulfur, depending on the amount of sulfur released from the organosilane polysulfide of the formula (II). The rubber was formed in batches in a mill, mixed in a mill for a short period of time, and rubber sheets were removed from the mill and allowed to cool to a temperature of about 30 ° C or less. the materials mentioned in Table 1 in a BR Banbury mixer using 3 separate stages of addition (mixing), namely, two stages of preparation mixing and a final mixing step at temperatures of 170 ° C, 160 ° C and 120 ° C and times of approximately 8 minutes, 2 minutes and 2 minutes, respectively, for the three stages of global mixing. The amounts of organosilane tetrasulfide and organosilane disulfide appear as "variables" in Table 1 and are presented more specifically in Table 2. Table 1 (floor) Parts Non-productive mixing stages Isoprene / butadiene rubber1 90 Rubber 1, 4-polybutadiene cis2"10 Processing aids3 12 Fatty acid4 1.5 Starch / plasticizer compound5 8 Silica6 58 Organosilane disulfide (A) 7 Variable Organosilane polysulfide (B) 8 Variable Production stage of mixing Sulfur9 ~ Variable Zinc oxide 2.2 Antioxidant (S) 10 - 2.5 Sulfenamide and guanidine type accelerators 3.5 Organosilane polysulfide (B) 8 Variable 1) Isoprene / butadiene copolymer elastomer (50/50 isoprene / butadiene) with a glass transition temperature about -44 ° C obtained from Goodyear Tire & Rubber Company. 2) cis 1,4-polybutadiene elastomer obtained as BUDENE ® 1207 from Goodyear Tire & Rubber Company. 3) Oil. 4) Stearic acid primarily. 5) Obtained as Mater Bi 1128RR from Novamont company as a starch and polyvinyl alcohol plasticizer compound with a ratio between the starch and the plasticizer of approximately 60/40. 6) Zeosil 1165 MP from Poulenc. 7) A compound commercially available from Degussa GmbH as X266S in the form of a 50/50 or composite mixture, of S266 (trademark of Degussa) and carbon black. YES 266 is a bis- (3-triethoxysilylpropyl) disulfide compound that has an average of about 2.2 sulfur atoms in its polysulfide bridge. Thus, the compound contains 50% of the coupling agent. 8) A compound commercially available from Degussa GmbH as X50S in the form of a 50/50 mixture of Si69, a trademark of Degussa GmbH, or what may be known as a bis- (3-triethoxysilylpropyl) compound having a average of approximately 3.8 sulfur atoms in its polysulphide bridge with carbon black and, therefore, tetrasulfide is considered as representing 50% of the compound and therefore 50% active. 9) can be obtained as S8 elemental sulfur from the Kali Chemie company of Germany. 10) A phenylenediamine type. The rubber compositions were cured (vulcanized) by heating for about 18 minutes at a temperature of about 150 ° C. The addition of the organosilane disulfide compound, organosilane tetrasulfide compound and free sulfur and the corresponding physical properties appear in the following table 2. Table 2 Sample number Ex. 1 Ex. 2 Ex.

Mixed non-productive Organosilane polysulfide (B) 12.1 0 0 Organosilane disulfide (A) 0 12.1 11.8 Productive mixture Sulfur 1.4 2 1.4 Organosilane polysulfide (B) 0 0 2 Physical properties Mooney1 - 52 49 45 Rheometer (150 ° C) Torque torque delta 28.4 32.4 29.7 T90, (minutes) 13.8 14.2 13.6 Effort-deformation Resistance to tension, Mpa 14.9 14.3 17 Elongation at break (%) 397 414 460 Module at 100% Mpa 2.4 2.6 2.1 Module at 300% Mpa 11.3 11.2 10.7 Module 300/100 4.9 4.5 5.0 Bounce 100 ° C (%) 72 69 70 23 ° C, (%) 45 42 43 Hardness Shore A 65 67.5 62 1) The viscosity of Mooney (ML-4) at 100 ° C of the rubber mixture coming from the productive mixing stage. Particularly, example sample 3 of this invention, as compared to example sample 1 which used the organosilane tetrasulfide compound (II) to generate free sulfur in the high nonproductive mixing stage (s) The temperature clearly shows the advantage of alternatively (1) first adding the organosilane disulfide that does not generate sulfur (I) in the non-productive mixing step so that its silane component reacts with both the starch compound and the precipitated silica, ( 2) adding in the second instance, in the subsequent productive stage of mixing at lower temperature, the organosilane tetrasulfide compound (II) together with a small amount of free sulfur followed by (III) the vulcanization with sulfur of the rubber composition. Particularly, the rubber composition properties based on starch compound reinforcement of the sample of example 3 shows that the addition of the organosilane disulfide compound (A), namely a compound of formula (I), during the mixing step not further productive the subsequent controlled addition of the compound (B) of bis- (3-triethoxysilylpropyl tetrasulfide), namely a compound of formula (II), in the productive mixing step resulted in a substantially increased tensile strength, improved elongation and a relatively increased modulus ratio in. comparison with the samples of example 1 and example 2, where the organosilane disulfide compound (A) or the organosilane polysulfide compound (B), respectively, is added in the non-productive mixing stage without significantly affecting the rebound values hot and cold. This is considered beneficial since it is considered here -that this indicates a better wear resistance of the floor (less wear) for the rubber composition of the example sample 3 of this invention without significantly affecting the wet traction and the rolling resistance. for the rim that has _a floor made with said rubber composition.

Furthermore, it is observed that the reduced Shore A hardness of the sample of Example 3, while still maintaining a modulus at 300% high, is an indication of reduced filler-filler interactions in the rubber composition while still maintaining high elastomer-filler interactions. . This phenomenon is considered due to an improved dispersion of the silica and starch compound within the elastomer. The balance of the filler-filler-interaction and the elastomer-filler interactions, in terms of the Shore A value and the modulus values at 300%, is considered here as significant and / or beneficial because the creation of a rubber composition slightly more Soft (Shore A hardness) while affecting stiffness (modulus at 300 percent) indicates a tire having a floor of said composition that exhibits better traction and resistance to skidding on wet surfaces without significantly affecting tire handling performance . In addition, the lower values of Mooney plasticity of the samples of example 2 and example 3, compared to the sample of example 1, as a measure of the viscosity of the rubber mixture, emphasize the advantage of using the compound (A) of organosilane disulfide compared to the use of the compound (B) of organosilane tetrasulfide which liberates sulfur in the non-productive mixing step, in terms of processing the compound. Accordingly, the use of the organosilane disulfide compound (B) of the formula (I) in the step or in the non-productive mixing preparation stages, while the compound (B) is subsequently added separately and organosilane polysulfide of the formula - (II) in the final, productive mixing step, significantly improving various properties of rubber composition together with improved rubber processing in the non-productive mixing stage (ie: lower rubber viscosity) ). Accordingly, it is considered here that it has been shown that, for the rubber composition reinforced with starch compound, a composition of mixing organosilane disulfide compound (B) with elastomer (s) and starch and precipitated silica compound in the mixing stage of non-productive preparation or in the non-productive preparation mixing stages, followed by the subsequent addition of a compound (B) of organosilane tetrasulfide prescribed in a final productive mixing step at the lower temperature increases the properties of the cured or vulcanized rubber composition. By this preparation of the rubber composition, the interaction of an organosilane disulfide compound with a starch compound and silica reinforcement is separated from a release of free sulfur as well as further interaction of silane from the compound (B) of tetrasulfide of organosilane added subsequently. EXAMPLE II Tires of size 195 / 65R15 having floors of the rubber compositions of Examples 1,2 and 3 of Example I were prepared for their floors. The results indicated in table 3 were obtained. For this table, the values of example 1 are normalized to 100 and the values of 2 and example 3 are normalized to those of example 1; one is normalized to a value of 100 and corresponding values for example 2 and example 3 are reported comparatively to control example 1.

For the normalized values reported in Table 3, a higher value for the rolling resistance means a lower resistance to the bearing in such a way that a high value is better; a higher value for floor wear means less floor wear in such a way that a higher value is better; and a higher value for patination in wet condition means a higher fraction and a resistance to skating on a higher wet surface such that a higher value is better. The tire handling value is a subjective test by a vehicle driver with a test tire (s) mounted on one or more of its wheels where a response (behavior) to severe maneuvering demands that may be experienced is evaluated. for example during a high-speed test lane change. It is considered here that said test is well known by experts in the field. Table 3 Ex. 1 Ex .2 Ex. 3 Bearing resistance 100 100 100 Tire wear 100 97 108 patinated in wet condition 100 100 102 Tire handling 100 95 100 This example demonstrates that a rim with a floor of the rubber composition of Example 3 provides better values of floor wear resistance (less wear) than rims with floors made with the rubber composition of Examples 1 and 2 while not substantially affects the rolling resistance and slightly increases the drag resistance value in wet condition without presenting a tire handling disadvantage. This is considered to be beneficial because wet patination, rolling resistance and compound processing are not affected. While certain representative embodiments and details were illustrated for the purpose of presenting the invention, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the spirit or scope of the invention.

Claims (2)

1. CLAIMS. . A process for preparing a rubber composition, characterized in that it comprises the steps of: (A) mixing thermomechanically in at least one preparation mixing step and at a temperature within a range of about 150 ° C to about 185 ° C and in the absence of addition of free sulfur (1) 100 parts by weight of at least one diene-based elastomer selected from conjugated diene homopolymers and copolymers and copolymers of at least one conjugated diene and aromatic vinyl compound, (2) from about 30 to about 100 phr of a particulate filler consisting of a) from about 4 to about 90% by weight of a starch / plasticizer compound and, correspondingly (b) from about 96 to about 10% by weight of at least one filler additional reinforcement selected from carbon black, alumina, and silica-based fillers selected from at least one of the following: precipitated silica, a luminosilicato, and modified carbon black containing silicon hydroxide on its surface; wherein said starch consists of amylose units and amylopectin units in the ratio of about 15/85 to about 35/65 and has a softening point in accordance with ASTM No. D1228 within a range of about 180 ° C to about 220 ° C and wherein said starch / plasticizer compound has a softening point within a range from about 110 ° C to about 170 ° C in accordance with ASTM No. D1228, and (3) from about 0.05 to about 20 parts by weight, per part by weight of said starch / plasticizer, alumina and silica-based filler compound, of at least one organosilane disulfide compound of the formula (I): (I) Z-R1-Sn-R1-Z followed by: B) Mixing sulfur and at least one organosilane polysulfide compound of the formula (II) there in a subsequent mixing step at a temperature within a range of about 100 ° C to about 130 ° C: (II) Z-Rl-Sm-Rl-Z where, n is a number within a range of 2 to about 6, and the average for n is within a range of about 2 to 2.6; where m is a number from 2 to about 8 and the average for m is within a range of about 3.5 to about 4.5; where Z is selected from the group consisting of: R2 R2 R3 (Zl) YES-R2 (Z2) YES-R3 (Z3) Si- • R3 III R3 R3 R3 where R2 may be identical or different and is selected individually within the group consisting of alkyl group having from 1 to 4 carbon atoms and phenyl radicals; R3 may be identical or different and is selected individually from the group consisting of alkyl radicals having 1 to 4 carbon atoms, phenyl, alkoxy radicals having 1 to 8 carbon atoms and cycloalkyl radicals with 5 to 8 carbon atoms. carbon; and R1 is selected from the group consisting of substituted or unsubstituted alkyl radicals having a total of 1 to 18 carbon atoms and substituted or unsubstituted aryl radicals having a total of 6 to 12 carbon atoms. The process of claim 1, characterized in that said starch / plasticizer compound has a weight ratio between the starch and the plasticizer within a range of about 0.5 / 1 to about 4/1, and where for said mixing step (B) The total addition of free sulfur and about 50% of the sulfur in the polysulfide bridge in said polysulfide compound is within a range of about 0.93 to about 4 phr. The process of any of the preceding claims, characterized in that said plasticizer is selected from at least one of the following: (poly) ethylene vinyl alcohol, cellulose acetate and diesters of dibasic organic acids having a softening point below 160 ° C and sufficiently below the softening point of the starch with which they are combined in such a way that the starch / plasticizer compound has a softening point within a range of about 110 ° C to about 170 ° C. The process of any of the preceding claims, characterized in that the organosilane component of said organosilane disulfide compound (I) reacts during said preparatory mixing step or said preparatory mixing steps with the starch compound and hydroxyl groups of at least 1 of said aluminosilicate, precipitated silica and black of modified smoke to form a silane-based compound, wherein said added organosilane polysulfide subsequently interacts with said previously formed silane-based compound and liberates free sulfur in a subsequent vulcanization of the rubber composition at a temperature within a range of about 140. ° C at approximately 190 ° C. The process according to any of the preceding claims, characterized in that said preparation mixing is carried out in at least two internal mixing steps for a total of internal mixing time for said preparation mixing steps (non-productive) within a range of about 4 to about 15 minutes and the mixing time for said subsequent (productive) internal mixing step is within a range of about 1 to about 3 minutes, and where between each mixing step the rubber composition is mixing in an open roller mill for from about 2 to about 6 minutes and then allowing it to cool to temperature below about 40 ° C; wherein said organosilane disulfide compound (I) and organosilane polysulfide compounds (II) are bis- (3-alkoxysilylalkyl) polysulfide compounds wherein the alkyl radicals of the alkoxy component are selected from methyl and ethyl radicals and the alkyl radical or the silylalkyl component is selected from the ethyl, propyl, and butyl radicals. The process of any of the preceding claims, characterized in that said organosilane disulfide compound (I) and said organosilane polysulfide compound (II) are bis- (3-alkoxysilylalkyl) polysulphide compounds wherein the alkyl radicals of the alkoxy component they are selected from methyl and ethyl radicals and the alkyl radical of the cycloalkyl components is selected from ethyl, n-propyl and butyl radicals. The process of any of the preceding claims characterized in that said organosilane disulfide compound (I) and said organosilane polysulfide compound (II) are individually added in the form of individual compounds consisting of from about 25 to about 75% by weight of the themselves and, consequently, of approximately 75 about 25% by weight of particulate carbon black. The process of any of the preceding claims, characterized in that said particulate reinforcement consists (a) of said starch compound and (b) said at least one precipitated silica, aluminosilicate and said modified carbon black; wherein said aluminosilicate is prepared by co-precipitation of the aluminum silicate and electrolytes to form a silica / aluminum compound containing from about 5 to about 95% by weight of aluminum, and wherein said modified carbon black is prepared by the reaction of an organosilane and carbon black at an elevated temperature and by co-flushing an organosilane and oil at an elevated temperature. . The process of any of the preceding claims, characterized in that a total of about 0.05 to about 5 phr of at least one alkylalkoxysilane is added to said preparation step or thermomechanical mixing steps; wherein said alkylsilane has the formula (III): (III) R'-Si- (0R ") 3 where R" is selected from at least one of the methyl, ethyl, propyl and isopropyl radicals and R'es saturated alkyl having from 1 to 18 carbon atoms or aryl or an aryl radical substituted with saturated alkyl having from 6 to 12 carbon atoms. The process of claim 9, characterized in that said alkylalkoxysilane is selected from at least one propyltriethoxysilane, methyltriethoxysilane, hexadecyltriethoxysilane and octadecyltriethoxysilane. The process according to any of the preceding claims characterized in that, for said diene-based elastomer, said conjugated dienes are selected from isoprene and 1,3-butadiene and said aromatic vinyl compounds are selected from styrene and alpha-methylstyrene. The process of any of the preceding claims, characterized in that said diene-based elastomer is selected from at least one natural rubber and a synthetic 1,4-polyisoprene rubber, styrene / butadiene copolymer rubber prepared by emulsion polymerization , styrene / butadiene copolymer rubber prepared by organic solution polymerization, 3, 4-polyisoprene rubber, isoprene / butadiene rubber, styrene / isoprene / butadiene terpolymer rubbers, cis 1,4-polybutadiene rubber, vinyl polybutadiene rubber medium (from 35 to 50% vinyl), polybutadiene with high vinyl content (from 50 to 90% vinyl) and styrene / butadiene / acrylonitrile terpolymer rubber prepared by emulsion and butadiene / acrylonitrile copolymer rubber polymerization. The process of any of the preceding claims characterized in that said organosilane disulfide for said organosilane disulfide compound is selected from at least one of the following: 2,2'-bis (trimethoxysilylethyl) disulfide; 3, 3'-bis (trimethoxysilylpropyl) disulfide; 3, 3'-bis (triethoxysilylpropyl) disulfide; 2, 2'-bis (triethoxysilylethyl) disulfide; 2, 2'-bis disulfide (tripropoxysilylethyl); 2, 2'-bis (tri-sec.butoxysilylethyl) disulfide; 3, 3'-bis (tri-t-butoxyethyl) disulfide; 3, 3'-bis triethoxysilylethyltolylene disulfide); 3, 3 '-bis trimethoxysilylethyltolylene disulfide); 3, 3'-bis triisopropoxypropyl disulfide); 3, 3 '-bis trioctoxypropril disulfide); 2,2'-bis-2'-ethylhexoxysilylethyl disulfide); 2, 2'-bis dimethoxy ethoxysilylethyl disulfide); 3, 3 '-bis methoxyethoxypropoxysilylpropyl disulfide); 3, 3 '-bis methoxy dimethylsilylpropyl disulfide); 3, 3'-biscyclohexoxy dimethylsilylpropyl disulfide); A, 4 '-bis trimethoxysilylbutyl disulfide); 3, 3 '-bis trimethoxysilyl-3-methylpropyl disulfide); 3, 3 '-bis tripropoxysilyl-3-methylpropyl disulfide); 3 / 3'-bis dimethoxymethylsilyl-3-ethylpropyl disulfide); 3 3 '-bis trimethoxysilyl-2-methylpropyl disulfide) 3,3'-bis-dimethoxyphenylsilyl-2-methylpropyl disulfide); 3 3 '-bis trimethoxysilylcyclohexyl disulfide); 12, 12'-bis (trimethoxysilyldodecyl) disulfide; 12, 12'-bis (triethoxysilyldodecyl) disulfide; 18, 18'-bis (trimethoxysilyloctadecyl) disulfide; 18,18'-bis (methoxydimethylsilyloctadecyl) disulfide; 2,2'-bis (trimethoxysilyl-2-methylethyl) disulfide; 2, 2'-bis (triethoxysilyl-2-methylethyl) disulfide; 2, 2'-bis disulfide (tripropoxysilyl-2-methylethyl); and 2,2'-bis (trioctoxysilyl-2-methylethyl) disulfide; wherein said organosilane polysulfide for said organosilane polysulfide (II) is selected from at least one of bis- (3-trimethoxysilylpropyl) trisulfide, bis- (3-trimethoxysilylpropyl) tetrasulfide, bis- (3-triethoxylylpropyl) trisulfide) , bis- (3-triethoxysilylpropyl) tetrasulfide, bis- (3-triethoxyoxyethylethylene) trisulphide and bis- (3-triethoxysilylethyltolylene tetrasulfide). The process of any of the preceding claims, characterized in that said organosilane disulfide for said organosilane disulfide compound (I) is 3,3'-bis (triethoxysilylpropyl) disulfide. The process of any of claims 1-13, characterized in that said organosilane disulfide for said organosilane disulfide compound (I) is 3,3'-bis (triethoxysilylpropyl) disulfide, and wherein said organosilane polysulfide for said organosilane organosilane polysulfide (II) is selected from at least one of the following: bis- (3-trimethoxysilylpropyl) trisulfide, bis- (3-trimethoxysilylpropyl) tetrasulfide, bis- (3-triethoxysilylpropyl) trisulfide, bis- tetrasulfide (3-triethoxysilylpropyl); bis- (3-triethoxysilylethyltolylene) trisulfide and bis- (3-triethoxysilylethyltolylene tetrasulfide). . The process of any of the preceding claims, characterized in that it comprises an additional vulcanization step with sulfur of the resulting mixed rubber composition at a temperature comprised within a range of about 140 ° C to about 190 ° C. . The process of claim 16, characterized in that, for said mixing step (B), the total addition of free sulfur and about 50% of the sulfur in the polysulfide bridge of said polysulfide compound is within a range of about 0.93 to about 2.8 phr.; A rubber composition characterized in that it is prepared by the process of any of the preceding claims. . The process of any of claims 1-17, characterized in that it comprises the additional steps of forming said rubber composition to obtain a rim floor, the application of said rim floor on a rim shell to form an assembly and mold and vulcanize said assembly in a mold suitable for forming a rim, and where for said mixing step (B), the total addition of free sulfur and about 50% _ of the sulfur in the polysulfide bridge of said polysulfide compound is found within a range of about 0.93 to about 4 phr. The process of any of the preceding claims 1-7, characterized in that it comprises the additional steps of forming said rubber composition in order to obtain a rim floor, applying said rim floor on a rubber rim shell to form an assembly. and molding and vulcanizing said assembly at a temperature within a range of about 140 to about 190 ° C to form a rim. A vulcanized rubber tire characterized in that it is prepared according to the process of claim 19 or claim 20. A tire characterized in that it has a component of the composition of claim 18. A manufactured article characterized in that it has at least one rubber composition component of claim 18. An industrial product characterized in that at least one of the following is selected: a band or a hose having at least one component of the rubber composition of claim 18.