MXPA97000990A - Composition of reinforced rubber with silice and silver with bearing band of the mi - Google Patents

Abstract

The present invention relates to a rubber composition characterized in that it is comprised of (A) 100 parts by weight of at least one diene-based elastomer, (B) from about 25 to about 100 phr of filler composed of precipitated silica, in particles and carbon black, and (C) a silica coupler selected from (i) mixture of 3,3'-tetrathiodipropanol polysulfide containing 1 to 8 sulfur atoms in the polysulfide bridge or (ii) a combination of about 95 to about 25 percent polysulfide mixture of 3,3'-tetrathiodipropanol and, correspondingly, about 5 to about 75 weight percent of bis- (3-trialkoxysilylalkyl) polysulfide containing from 2 to 8 atoms of sulfur in its polysulphide bridge where the weight ratio of the silica-silica coupler is in the range of about 0.01 / 1 to about 0.2 / 1, where the weight ratio of silica to carbon black is at least approximately 0.1

Description

COMPOSITION OF REINFORCED RUBBER WITH SILICA AND RIM WITH BAND OF BEARING THE SAME FIELD This invention relates to rubber compositions containing silica reinforcement and to rims having treads thereof. In one aspect, the rubber composition is comprised of rubber, particularly sulfur-cured rubber, reinforced with a combination of silica, and optionally carbon black, and a mixture of 3,3'-tetra-t-iodipropanol polysulfide as an of copulation.

BACKGROUND For various applications utilizing rubber that requires high strength and abrasion resistance, particularly applications such as sprays and various industrial products, sulfur-cured rubber is used that contains substantial amounts of reinforcing fillers, often in a scale of about 35 to about 85 parts by weight per 100 parts of rubber. The carbon black is commonly used for that purpose and usually provides or improves the good physical properties for the sulfur cured rubber. Particulate silica is also frequently used for this purpose, particularly when silica is used in conjunction with a coupling agent. In some cases, a combination of silica and carbon black is used for reinforcements for various rubber products, including rip bands for tires. The use of such reinforcing fillers for elastomers, including sulfur curable elastomers, is well known to those skilled in the art. It is important to note that, conventionally, carbon black is a considerably more effective reinforcing filler for rubber products, and particularly that rubber tire treads than silica if silica is used without a coupling agent. , or silica coupler or silica adhesion agent, as may be sometimes referred to herein. These coupling agents can, for example, be premixed, or pre-reacted, with the silica particles or added to the mixture of cuacho during a rubber / silica processing, or mixing step. If the coupling agent and silica are added separately to the rubber mixture during rubber / silica mixing, or processing step, it is considered that the coupling agent is then combined in situ with the rubber. In particular, said coupling agents are sometimes composed of a silane having a constituent component, or fraction, (the silane portion) capable of reacting with the silica surface and, also, a constituent constituting a fraction, or fraction thereof. , capable of reacting with rubber, particularly a vulcanizable rubber with sulfur containing double bonds of carbon to carbon, or unsaturation. In this way, when the copulator acts as a connecting bridge between the silica and the rubber and of this sleeve the rubber reinforcement aspect of the ice. In one aspect, the silane of the coupling agent apparently forms a bond with the silica surface and the rubber reactive component of the coupling agent is combined with the rubber itself. Usually the reactive rubber component of the copulator is sensitive to temperature and tends to. combine with the rubber during the final stage and vulcanization with azu fre at higher temperature and, in this way, after the rubber mixing stage / yes 1 ice / copulator and, therefore, after the silane group of the copulator has been combined with the ce. However, in part because of the typical temperature sensitivity of the copulator, some degree of combination, or bond, between the reactive rubber component of the copolymer and the rubber may occur during the initial stage of rubber / ice mixing. / copulator and, in this way, before a subsequent vulcanization stage. The rubber reactive group component of the coupler can be, for example, one or more of the groups such as mercapto, amino, vinyl, epoxy and sulfur groups, and often is a sulfur or mercapto moiety and more usually sulfur.E.

Numerous ag couplers are taught for use in the combination of silica and rubber, such as, for example, silane coupling agents containing a polysulfide component, or structural, such as, for example, trialcox organosilane polysulfides containing from 2 to 8 atoms of sulfur in a polysulphide stick such as, for example, tetrasulfide and / or trisulfur of bis- (3-triethoxysi 1 i-propyl). Various United States patents relating to silicon-reinforced rims and tire treads include, for example, U.S. Patent Nos. 3,451, 3,664,403; 3,768,537; 3,884,285; 3,938,574; 4,482, -663; 4,590,052; 5,089,554 and British 1,424,503. Various hydroxysulfides have also been used to reinforce silica in rubber filled with carbon black (Publication of pathene EP No. 489,313). The term "phr" if used herein, and in accordance with conventional practice, refers to "respective material parts per 100 parts by weight of rubber, or elastomer." In the description of this invention, the terms "cacho" and "elastomer" if used herein, may be used interchangeably, unless otherwise prescribed. The terms "rubber composition", "compound rubber" and "rubber compound", if used herein, are used interchangeably to refer to "rubber that has been mixed with various ingredients and materials" and such terms They are well known to those who have experience in mixing rubber or rubber composition bouquet. A reference to a Tg of elastomer refers to its glass transition temperature, which can be determined by means of a "differential scanning calorimeter" with a heating rate of 10dC per minute.

SUMMARY AND PRACTICE OF THE INVENTION In accordance with one aspect of this invention, a rubber composition comprising (A) 100 parts by weight of at least one diene-based elastomer, (B) of about 25 a is provided. about 100, optionally from about 35 to about 90, filler phr composed of carbon black silica, and (C) a silica coupler selected from (i) mixture of 3,3 '-tetrathiodipropanol polysulfide or ( ii) a combination of from about 95 to about 25, optionally from about 90 to about 55, by weight by weight of 3,3 '-tetrathiopipropanol polysulfide mixture containing 1 to 8 atoms in the polysulfide bridge, and correspondingly, from about 5 to about 75, alternatingly from about 10 to about 45, percent by weight of bi-s- (3-trialkoxy if 1-alkyl) polysulfide containing from 2 to 8 carbon atoms. sulfur in the polysulfide bridge, ta l such as, for example, at least one of bi-s- (3-trietoxyl silylpropyl) trisulphide and bi-s- (3-triethoxy si-1-propyl) trisulphide; wherein the weight ratio of silica to carbon black is at least 0.1 / 1, optionally at least 3/1 and optionally at least 10/1. Typically, it is desired that the weight ratio of the silica-to-silica co-polymer be on a scale of about 0.01 to about 0¿2 / 1. In one aspect of the invention said rubber composition is provided which is comprised of (A) 100 parts by weight of at least one diene-based elastomer, (B) from about 25 to about 90 phr of particulate silica. , (C) to approximately 30 phr of carbon black, and (D) a silica coupler which is collectively composed of from about 90 to about 55 weight percent of 3,3 '-tetrathiodipropanol from about 10 to about 45. percent by weight of at least one of tetrasulfide of bi-s- (3-triethoxysi-1-propyl) and bis- (3-triethoxysi-1-propyl) trisulphide, where the weight ratio of silica to black of coal is on a scale of about 3/1 to about 30/1; wherein the silica is characterized by having a BET surface area on a scale of about 50 to about 300 square meters per gram and an abosrtion value of dibutyl phthalate (DBP) in a scale of about 150 to about 300 Typically, it is desired that the weight ratio of the silica to silica co-polymer be on a scale of about 0.1 / to about 0.2 / 1.

Thus, in one aspect of the invention, the rubber composition contains a combination of both silica and carbon black d as elastomer reinforcing pigments. The rubber composition may contain a minor amount of silica in its silica / carbon black or may be quantitatively reinforced with silica when the carbon black is present in a smaller amount. In another aspect of the invention, a rim is provided having a tread comprised of the rubber composition of this invention. The mixture of 3, 3 '-tetrathiodipropanol polysulphide can be described more fully as a difunctional alcohol which is strongly polar to the silica and reacts further with a diene polymer through its polysulfide bridge containing 1 to 8. sulfur atoms. The 3, 3 '-tetrathiodipropanol polysulfide is mentioned herein as a mixture because all possible sulfide sites with 1 to 8 sulfur atoms are present. It is believed that the mixture of 3, 3 '-tetrathiopropanol polysulfide, with alcohol / asycharide suction with the surface of the silica, acts to pull the silica filler closer to the diene rubber and, thus, gives much better dispersion of the silica towards the rubber compound, apparently inhibiting the go, or retarding, the tendency of the silica particles to agglomerate together. This is considered in the present to be beneficial because the better the dispersion of silica within the rubber (ie, less silica agglomeration) is expected to provide better physical properties to the rubber. In practice, preferably the 3, 3 '-tetrathiodipropanol polysulfide mixture is reacted, or made to associate with the silica in situ by mixing it and the silica together with the rubber compound instead of reacting them beforehand. to add them to the rubber composition. When it is desired that the rubber composition be reinforced primarily with silica as the reinforcing pigment, it is preferable that the weight ratio of silica to carbon black be at least 3/1, preferably at least 10/1, and thus, for example, on a scale of about 3/1 to about 30/1. In one aspect of the invention, the silica coupler consists essentially of the polysulfide ezefa of 3,3'-tetra thiopropanol. In a further aspect, the silica coupler can be composed of a combination of polysulfide blend of 3,3 '-tetrathiodipropanol together with bis- (3-triethoxy si-1 -propylous) tetrasulfide and / or a mixture of said tetrasulfide and bis- (3-triethoxysi-1-propyl) trisulfide). 3,3'-Tetrathiodipropanol can also be referred to as an associative alcohol coupler. In one aspect, it can also be referred to as a silica-to-non-silicone rubber coupler. In particular, it can be characterized in that it has the properties of being a highly viscous liquid with a medium intensity infrared spectrometric absorption bond in a range of about 3570c "to about 3450 ° for the alcohol functional group. Field chromatography and gas chromatograph spectrometry indicate that the polysulfide of 3,3'-tetrathiodipropanol has 1 to 8 sulfur atoms in the polysulfide bridge, and the poly isulfide mixture of 3,3 '-tetrathiodipropanol is it is hereby considered to be particularly advantageous for the practice of this invention because it has a very strong associative attraction to silica and high reactivity for rubber, which is considered to be a benefit to the exceptionally good dispersion of silica towards the rubber. Historically, the more homogeneous the dispersion of rubber compound components into rubber, the better the cured properties. before that rubber. The strong association of 3, 3 '-tetrathiodipropanol with silica and the high affinity, compatibility and reactivity with rubber are considered in the present to lead to excellent silica dispersion. In one aspect, said rubber composition can be donated as being cured by sulfur. Sulfur curing is achieved in a conventional manner, ie, curing under high temperature and pressure conditions for an appropriate period of time. In the practice of this invention, as noted above, the rubber composition is comprised of at least one diene-based elastomer, or rubber. In this way, it is considered that the elastomer is a curable elastomer with azu fre. Said elastomer, or rubber, may be selected, for example, from at least one of cis 1, 4-pol ii sopr rubber (natural and / or synthetic rubber, and preferably natural), rubber of 3, 4-poly isoprene, styrene / butadiene copolymer rubbers, styrene / i soprene / butadiene terpolymer rubbers and cis 1,4-polybutadiene rubber. In one aspect, the rubber is preferably at least two diene-based rubbers. Said diene-based rubbers may, for example, be of homopolymers and copolymers of conjugated diene hydrocarbons and copolymers of at least one hydrocarbon diene with an aromatic vinyl compound. These diene hydrocarbons can be, for example, selected from 1,3-butadiene and isoprene. This aromatic vinyl compound can be, for example, styrene and alphamethylstyrene. For example, a combination of two or more rubbers is preferred as to how much less elastomers selections of cis 1,4-isoprene rubber do not (natural or synthetic rubber, even when natural is preferred), rubber 3 , 4rpol ii soprene, isoprene / butadiene rubber, styrene rubber / i soprene / butadiene, styrene / butadiene rubbers derived by emulsion and solution polymerization, cis 1, 4-polybutadiene rubber, vinyl polybutadiene rubber medium having a vinyl content of 30 to 50, and high vinyl polybutadiene having a vinyl content of 50 to 75, and butadiene / acrylonitrile copolymers prepared by emulsion polymerization. In one aspect of this invention, a styrene / butadiene derived from emulsion polymerization (E-SBR) could be used having a relatively conventional styrene content of from -about 20 to approximately 28 percent bound styrene, or for some applications, a E-SBR that has a. medium to relatively high bound styrene content, ie, a bound styrene content of from about 30 to about 45 percent. A relatively high styrene content of from about 30 to about 45 for the E-SBR can be considered beneficial for a purpose of improving the traction, or skid resistance, of the tire tread. The presence of the E-SBR itself is considered beneficial for a purpose of improving the processability of the uncured elastomer composition mixture, especially as compared to the use of an SBR prepared by solution polymerization (S-SBR). Medianete E-SBR prepared by emulsion polymerization, it is implied that styrene and 1,3-butadiene are copolymerized in an aqueous emulsion. This is well-known to those experienced in that field. The bound styrene content may vary, for example from about 5 to 50%. 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 to about 30 weight percent acrylonitrile bound in the terpolymer. . Styrene / butadiene / acrylonitrile copolymer rubbers prepared by emulsion polymerization containing from about 2 to about 40 percent acrylonitrile bound in the copolymer are also contemplated as diene based rubbers for use in this invention. The SBR prepared by polymerization by eoslution (S-SBR) typically has a bound styrene content on a scale of about 5 to about 50, preferably from about 9 to about 36 percent. The S-SBR can conveniently be prepared, for example, by catalyzing the lithium organ in the presence of an organic hydrocarbon solvent. A purpose of using S-SBR is for improved tire bearing strength as a result of the lower hysteresis when used in a tire tread composition. The rubber of 3,4-poly isoprene (3,4-PI) is considered be. Nephric for a purpose of improving tire traction when used in a tire tread composition The 3,4-PI and the use thereof is more fully described in U.S. Patent No. 5,087,668, which is incorporated herein by reference. Tg refers to the glass transition temperature which can be determined conveniently by a differential scanning calorimeter at a heating regime of 109 C per minute. The cis 1,4-polybutadiene rubber (BR) is considered to be beneficial for a purpose of improving tire tread wear, or tread wear. This BR can be prepared, for example, by polymerization of 1, 3-butadiene organic solution. The BR can be conveniently characterized, for example, by having at least 90% cis 1,4- cis 1,4, isoprene and natural cis 1, polyisoprene rubber are well known to those having Experiment in the rubber technique. The vulcanized rubber composition should contain a sufficient amount of silica, and carbon black reinforcement filler (s) to contribute to a reasonably high modulus and tear resistance. The combined weight of the carbon black and carbon, as mentioned above, may be as low as about 30 parts per 100 parts of rubber, preferably about 35 or 45 to about parts by weight. The silicious pigments commonly used in rubber composition applications can be used as the silica in this invention, including pyrogenic silicate pigments and precipitates (silica) s even when precipitated silicas are preferred. The siliceous pigments preferably 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 on the scale of about 40 to about 600, and more usually on a scale of about 50 to about 300 square meters per gram. The BET method for measuring surface area is described in the Journal of the American Chemical Society, Volume 60, page 304 (1930). Silica can also be characterized typically by having an absorption value of dibutyl phthalate (DBP) on a scale of about 100 to about 400, and more usually about 150 to about 300. The silica could be expected to have an average final particle size, for example, on the 0.01 to 0.05 micron scale as determined by the microscope electronic, even though the silica particles may be even smaller, or possibly larger, in size. Various commercially available silicas can be considered for use in this invention, such as for example only herein, and without limitation, silicas commercially available from PPG Industries under the trademark Hi-Sil with desi nations 210, 243, etc .; available silicas from Rhone-Poulenc, for example, with Zeosil 1165MP and silicas available from Degussa AG with, for example, designations VN2 and VN3, etc. It is readily understood by those of ordinary skill in the art that the rubber composition would be compounded by methods generally known in the rubber composition field, such as by mixing the various vulcanizable constituents with sulfur with various protective materials. commonly used such as, for example, curing aids, such as sulfur, activators, retarders and accelerators, processing additives, such as oils, resins including tackifying resins, silicas and plasticizers, fillers, pigments, fatty acid, zinc oxide , waxes, antioxidants and antiozonants peptizing agents and reinforcing materials such as, for example, black decarbon. As is known to those experienced in the art, depending on the intended use of the vulcanizable material with sulfur and vulcanized with sulfur (rubbers), the additives mentioned above are selected and commonly used in conventional amounts. Typical amounts of carbon black (s) of reinforcement type d, for this invention, if used, are discussed above. It should be noted that the silica coupler can be used in conjunction with a carbon black, ie, pre-mixed with a carbon black prior to the addition to the rubber compound, and said carbon black must be included in the aforementioned amount. of carbon black for the formulation of rubber composition. 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 may be, for example, difeni 1-p-phenylenediamine and others, such as, for example, those described in the Vanderbilt Rubber Handbook (1978), pages 344-346. Typical amounts of antiozonant comprise about 1 to 5 phr. Typical amounts of fatty acids, if used, which may include stearic acid, comprise about 0.5 to about 3 phr. The typical amounts of zinc oxide comprise about 2 to about 5 phr. Typical amounts of waxes comprise about 1 to about 5 phr. Inas microcrystals are often used. Typical amounts of peptizers are from about 0.1 to about 1 phr. Typical peptizers may be, for example, pentachlorothiophenol and dibenzamidodiphenol disulfide.

The vulcanization is conducted in the presence of a vulcanization agent with sulfur. Examples of suitable sulfur vulcanization agents include elemental sulfur (sulfur) or sulfur donor vulcanizing agents, for example an amine disulfide, polymeric polysulfide or sulfur olefin adducts. Preferably, the azu fre vulcanization agent is elemental sulfur. As known to those experienced in the art, sulfur vulcanization agnes are used in an amount ranging from about 0.5 to about 4 phr, or even, in some circumstances, up to about 8 phr, with a scale from around 1.5 to approximately 2.5, sometimes from 2 to 2.5, being preferred. Accelerators are used to control the time and / or temperature required for vulcanization and to improve the vulcanization properties. In one embodiment, a single accelerator system, i.e. primary accelerator, can be used. Conventionally and preferably, a primary accelerator (s) is used in total amounts ranging from about 0.5 to about 4, preferably from about 0.8 to about 1.5 phr. In another embodiment, the combinations of a primary accelerator and a secondary accelerator could be used with the secondary accelerator being used in smaller amounts (from about 0.05 to about 3 phr) in order to activate and improve the properties of the vulcanizate. The combinations of these accelerators could be expected to have a synergistic effect on the final properties and are somewhat better than those produced by the use of any single accelerator. In addition, delayed action accelerators can be used that are not affected by normal processing temperatures but produce a satisfactory cure at ordinary vulcanization temperatures. Vulcanization retarders could also be used. The appropriate types of accelerators which can be used in the present invention are amines, disulfides, guan dines, thioureas, thiazoles, thiura s, sulfenamides, dithiocarbamate and xanthates. Preferably, the primary accelerator is a sulfe ida ida. If a second accelerator is used, the secondary accelerator is preferably a guanidine, dithiocarbamate or thiuram compound. The presence and relative amounts of vulcanization agent with sulfur and accelerators) are not considered to be an aspect of the invention that is primarily directed to the use of silica as a reinforcing releln in combination with a polysulfide mixture of 3. , 3 '-tetra iodipropanol as a coupling agent for the reinforcement filling. The presence and the relative amounts of the above additives are not considered to be an aspect of the present invention which is directed more primarily to the use of specified blends of rubbers in rubber compositions, in combination with silica with a mixture of polysulfide 3. , 3 '-tetrati dipropanol individually or in combination with tetrasulfide of bi s- (3-trietoxy si 1 protile) (a mixture of polysulfide) as well as optionally, carbon black, for rubber reinforcement. 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, say, at least one non-productive stage followed by a productive mixing step. The final curatives are typically mixed in the final stage which is conventionally referred to as the "productive" mixing step in which the mixing typically occurs at a temperature, or final temperature, lower than the mixing temperature (s) non-productive mixing stages above Silica rubber, silica and copulator and carbon black, if used, are mixed in one or more stages of non-productive mixing. The terms "non-productive" and "productive" mixing stages are well known to those having experience in the field of rubber mixing. The rubber composition of this invention can be used for various purposes. For example, can be used for various rim compounds. These lalntas can be constructed, shaped, modulated and cured by various methods that are well known and will be readily apparent to those who are experienced in such a technique. The invention can be better understood by reference to the following examples in which the parts and percentages are by weight, unless otherwise indicated.

EXAMPLE I In this example, a mixture of polysulfide d 3,3 '-tetrathiodipropanol was evaluated on a carbon black proter with an alternative for a silica coupling agent relatively commonly used, namely, a mixture of polysulfide tetrasulfide of bis- (3-trietoxisi 1 i Ipropi), on a carbon black as a carrier, in a composition of reinforced rubber with silica. The rubber compositions containing the materials shown in Table 1 were prepared in a Banbury BR blender using three separate, sequential steps of addition (mixing), namely, two stages of non-productive mixing and one, productive mixing. final at temperatures of 1609C, 1609C and 120QC and times of 4 minutes, 4 minutes and 2 minutes, respectively. The amount of copulant is listed as being "variable" in Table 1 and set forth more specifically in Table 2. It is clearly evident that the use of the copying agent appears to be necessary to obtain appropriate cured properties in a composition of silica-containing rubber or composite These properties include resistance to tensile stress, modulus values at 100 and 300%, rebound hardness, Reovibron E 'and particularly resistance to DIN abrasion (lower abrasion values indicate less or better values.) Samples 2 and 3, when compared to Sample 1, which was prepared in the absence of use of the sizing agent, clearly show the advantage of the coupling agents. The properties of Sample 3 , which contains the crosslinker used in this invention has properties comparable to those exhibited by Sample 2 containing the conventional silane coupling agent. In particular, this Example shows that the mixture of 3,3 '-tetrathiodipropanol polysulfide, as used in Sample 3, can provide significant improvements in modulus, rebound, hardness and abrasion when compared to the control of the Sample. 1, which does not contain coupling agent. In addition, these properties compare favorably with those of Sample 2 containing the conventional silane coupling agent.

Table 1 1a. Non-productive i Natural Rubber 100.00 Carbon black 35.00 Processing Oil 5.00 Zinc Oxide 5.00 Fatty Acid 2.00 Antioxidant 2.00 2a. No Productive Yes 1 ice '15.00 Tetrasulfide of bis- (3-trietoxy si1 iproject) variable Table 1 (continued) 2a. Non-productive 3,3% -tetrathiodipropanol polysulphide mixture Productive Sulfur 1.40 Accelerator, sulfenamide type 1.00 D Synthetic cis 1, 4-poly isoprene rubber (NAT 2200) from The Goodyear Tire & Rubber Company; 2) of the type of 1, 2-dihydro-2, 2,4-trimeti lquinol ina polymerized; 3) silica obtained as Hi-Sil-210 from PPG Industries, Inc 4) 50% active compound composed of the org nosilane tetrasulfide on or with carbon black in a weight ratio of 50/50 available as X50S material from Degussa GmbH. Technically, the organosilane polysulfide is understood to be a compound, or mixture, wherein the average p-lissulfide bridge contains about 3.5 to 4 atoms of sulfur connection, although the mixture may contain such polysulfides with about 2 to 8 ato sulfur connection. 5) 3, 3 '-tetrathiodipropanol polysulfide containing 1 8 zzufre atoms in the polysulphide bridge obtained as a highly viscous liquid from the reaction of 3-chloropropanol (two molar equivalents) with 1 molar equivalent of tetrasulfide aqueous sodium. It is supported 1 to 1 by weight on carbon black N330 for all the examples used in this specification. Table 2 Sample # 1 2 3 X50S (Degussa GmbH) 0 3 0 3,3 '-tetrathiodipropanol 0 0 2 Rheometer (150SC) Torque Max. dNm 30.2 or 34.3 33.0 Torque torque Min. DNm 7.0 7.0 7.0 Torque torque Delta 23.2 27.3 26.0 TgQ, minutes 23.0 18.7 17.0 Effort-Tension Resistance to tension, MPa 17.6 19.7 18.8 Elongation at break, T 630 621 626 Module 100%, MPa 1.2 1.7 1.5 Module 300%, MPa 5.5 8.0 6.8 Bounce 1002C, T 55.1 59.8 58.6 Shore A hardness, lOO ^ C 46.4 51.9 51.2. Rebounded E1 to 609C, MPa 10.6 11.5 10.4 Delta Tan to 60% 0.105 0.092 0.0 Abrasion DIN 231 156 186 EXAMPLE II In this example, 3.3-tetraiodipropanol polysulfide mixture was evaluated on a carbon black carrier as a silica coupling agent in a rubber composition refoamed with silica. The rubber compositions containing the materials shown in Table 3 were prepared in a Banbury BR rubber mixer using three separate, sequential stages of addition (mixing), namely two stages of non-productive mixing and final productive mixing. at temperatures of 160 ° C, 160 ° C and 120 ° C and times of 4 minutes, 4 minutes and 2 minutes, respec- tively. The amount of coupler is listed in the Table and is more specifically set forth in Table 4. It is clearly evident that the use of the coupling agent appears to be necessary to obtain appropriate cured properties in a rubber composition containing silica. These properties include tensile strength at break, modulus values of 100 and 300%, rebound hardness, Reovibron E 'and particularly DIN abrasion resistance (lower abrasion values indicate less or better values). La Mute 5 of Table 4, when compared to Sample 4 of Quad 4, which was prepared in the absence of use of the silica copolymer, clearly shows the advantage of the co-blowing agent. This Example illustrates that the mixture of 3,3 '-tetrathiodipropanol polysulfide, as used in Sample 5, can provide improvements in modulus, rebound, hardness and abrasion when compared to control sample 4 which does not contain copulac agent. ion.

Table 3 1st Non-Productive Natural Rubber 100.0 Silica2 20.0 Carbon Black 15.0 Processing Oil 5.0 Zinc Oxide 5.0 Fatty Acid 2.0 3 Antioxidant 2.0 Mix of polysulfide of 3,3 '-tetrathiodipropanol 0 or 3.0 2o. No Productive Silica '15.0 Productive Sulfur 2.0 Accelerators, sulfenamide type 2.5 Diphenyl guanidine 1.0 1) Synthetic cis 1, 4-poly isoprene rubber (NAT 2200) d The Goodyear Tire & Rubber Company; 2) silica obtained as Hi-Si 1-210 from PPG Industries, In 3) of the type of 1, 2-dihydro-2, 2, 4-trimeti Iquinol inapolimized; 4) 3, 3 '-tetrathiodipropanol polysulphide containing 1 8 sulfur atoms in the polysulfide bridge botenid as a highly viscous liquid from the reaction of 3-chloropropanol (two molar equivalents) with 1 molar equivalent of tetrasulfide aqueous sodium, is supported 1 to 1 by weight on carbon black N330 for all the examples used in this specification.

Table 4 Sample # 4 5 Mix of 3,3 '-tetrathiodipropanol 0 3 Rheometer (150SC) Torque M x, dNm 50.1 48.5 Torque torque Min, dNm 8.3 5.0 Torque torque Delta 41.8 43.5 90 minutes 14.3 10.0 Stress-Stress Stress Resistance, IPa 18.4 19.2 Elongation at Break, 574 526 Module 100%, MPa 1.9 2.6 Module 300%, MPa 6.8 9.9 Rebound 100SC,% 64.9 66.8 Table 4 (continued) Sample # Hardness Shore A, lOO ^ C 62.9 64.8 Reovibron E 'at 609C, MPa 19.1 20.0 Delta Tan at 60' 0.050 0.05 Abrasion DIN 193 180 EXAMPLE III In this example, a mixture of 3, 3 '-tetrathiodipropanol polysulfide was evaluated as a coupling agent in a composition of carcharine highly charged with silica. The rubber compositions containing the materials shown in Table 5 were prepared in a Banbury BR mixer using three separate, sequential stages of addition, ie, two stages of non-productive mixing and one stage of productive mixing at tempratures. of 160SC, 160 QC and 1 0 SC and times of 4 minutes, 4 minutes and 2 minutes, respectively. The curing behavior and the cured properties are indicated in Table 6. The use of 3, 3 '-tetrathiodipropanol polysulfide alone in combination with the conventional coupling agent provided rubber compositions exhibiting excellent curing properties in the presence of Elevated silica filler.

Table 5 1st Non-Productive Styrene / Butadiene Rubber 68.75 2 Polybutadiene Rubber 15.00 Natural Rubber 35.00 3 Black Carbon 20.00 Silica4 40.00 Zinc Oxide 3.00 Fatty Acid 3.00 5 Antioxidant 2.0G Processing Aid 5.00 p 3, 3 'Sulfide-tetrathiodiprooanol 4.00 2nd Non-Productive Silica4 30.00 Tetrasulfide of bis- (3-trietoxisi 1 i lpropi lo '(50% active) 0 or 3.00 o Polysulphide of 3, 3' -tetrathiodipropanol 0 or 3.00 Productive Sulfur 1.40 Accelerator, sulfenamide type 1.80 Difeni lguanidine 1.50 1) Styrene / butadiene copolymer elastomer prepared by emulsion polymerization containing 23.5% bound styrene and 37.5 phr aromatic oil from The Goodyear Tire & Rubber Company; ) cis-1, 4 = elevated polybutadiene from The Goodyear Tire & Tubber Company; Carbon black like N330; Zeosil 1165 MP from Thone-Poulenc; type 1, 2-dihydro-2, 2, 4-trimeti Iquinol ina polymerized Struktol A6; 50% active compound composed of or ganosilane tetrasulfide on or with carbon black in a 50/50 weight ratio available as X50S material from Degussa GmbH. ) 3, 3 '-tetrathiodipropanol polysulphide containing 1 8 sulfur atoms in the polysulphide bridge obtained as a highly viscous liquid from the reaction of 3-chloropropanol (two olare equivalents) with 1 molar equivalent of sodium tetrasulfide aqueous. It is supported 1 ai by weight on carbon black N330 for all the examples used in this specification.

Table 6 Sample # 6 7 X50S (Degussa GmbH) 3.0 0 3,3 '-tetrathiodipropanol 4.0 7.0 Rheometer (150 ° C) Torque Max, dNm 45.0 41.4 Torque torque Min., DNm 10.0 9.0 Torque Torque Delta 35.0 32.5 Tg0 > Minutes 17.5 25.0 Stress-Tension Stress Resistance, MPa 13.0 11.9 Elongation at Break, T 74 548 Module 100%, MPa 2.54 2.0 Module 300%, MPa 8.75 6.14 Bounce 1002C,% 52.5 46.9 Hardness Shore A, 100 ^ 0 59.9 55.3 Reovibron E1 at 609C MPa 37.6 35.0 Delta tan at 60% 0.086 0.100 Abrasion DIN 147 161 Even though certain modalities and representative details have been shown with the purpose of illustrating the invention, it will be evident to those experienced in this field that can be done in the same several changes and modifications without abandoning the spirit or scope of the invention.

Claims (8)

1. - A rubber composition characterized in that it is comprised of (A) 100 parts by weight of at least one diene-based compound, (B) of from about 25 to about 100 phr of filler composed of precipitated silica, in particle and carbon black, and (C) a silica coupler selected from (i) mixture of 3,3 '-tetrathiodipropanol polysulfide * containing 1 to 8 sulfur atoms in the polysulfide bridge or (ii) a combination of from about 95 to about 25 percent polysulfide mixture of 3,3 '-tetrathiodipropanol and correspondingly from about 5 to about 75 weight percent of bis- (3 = trialkoxysi 1 and lalkyi) polysulfide containing from 2 to 8 sulfur atoms in its polysulfide bridge where the weight ratio of the silica-silica coupler ranges from 0.01 / 1 to about 0/2/1; wherein the weight ratio of silica to carbon black is at least about 0.1 / 1.

2. The rubber composition of claim 1, characterized in that the silica coupler consists essentially of a mixture of 3,3 '-tetrathiodipropanol polysulfide; and in C of the weight ratio of the silica-silica coupler is on a scale of about 0.01 / 1 to about 0.2 / 1.

3. The rubber composition of any of the above claims, characterized in that the mixture of 3,3 '-tetrathiodipropanol poly sulfide is supported on carbon black port.

4. The rubber composition of any of the preceding claims, characterized in that the copolymer is a blend of from about 95 to about 25 weight percent of polysulfide mixture of 3, 3 '-tetrathiodipr panol and, correspondingly, about 5 to about 75 weight percent of bis- (3-triethoxysi-1-propeny tetrasulfide) and bis- (3-triethoxy? si-1-propyl) trisulphide. Rubber composition of any of the preceding claims, characterized in that the diene elastomer ab is selected from at least one of 1,4-poly isoprene rubber, 3,4-poly isoprene rubber, styrene / butadiene copolymer rubbers,? soprene / butadiene rubber, styrene / isoprene / butadiene terpolymer rubbers, cis 1,4-ibutadiene rubber, medium vinyl polybutadiene rubber, high vinyl polybutadiene rubber and rubber of styrene / butadiene terpolymer / acrylic Nitri was prepared by polymerization of emulsion and butadiene copolymer / acrylonitrile rubber. 6. The rubber composition of any of the preceding claims, characterized in that the silica is faced by having a BET surface area on an alder scale from 50 to about 300 square meters per gram and an absorption value. of dibutyl phthalate (DBP) on a scale of from about 150 to about 300. 7. A rubber composition characterized in that it is comprised of (A) 100 parts by weight of at least one diene-based compound. , (B) from about 25 to about 90 phr of particulate silica, (C) to about 30 phr of carbon black, and (D) a silica coupler that is collectively composed of from about 90 to about 55 po weight percent of 3,3 '-tetrathiodipropyl polysulfide mixture, about 10 to about 45 * percent by weight of bis- (3-triethoxysi-1-propyl) tetrasulfide, and bis (3-triethoxysi-1) trisulfide. i lpropi lo where the weight ratio d the silica-to-silica coupler is on a scale of about 0.01 / 1 to about 0.2 / 1; wherein the weight ratio of silica to carbon black is on a scale of about 3/1 to about 30/1; wherein the silica is characterized as having a BET surface area on a scale from 50 to about 300 frames per gram and an absorption value of dibyl phthalate (DBP) on a scale of about 150 to about 300. 8 .- A lantanta that has a rubber tread band where the tread is characterized by being comprised of the rubber composition of any of the previous claims.