MXPA97001546A - Process for the preparation of a reinforced rubber composition in particu - Google Patents

Abstract

The invention relates to a process for the preparation of a rubber composition which involves thermomechanically mixing in a preparatory mixing step, at least one elastomer vulcanizable with sulfur, a particulate filler and a non-symmetrical organosilicon disulfide compound of the formula (See Formula) wherein Z is selected from the group consisting of: (See Formula) wherein R2 may be the same or different and is independently selected from the group consisting of an alkyl group having 1 to 4 carbons and phenyl R3 may be the same or different and is independently selected from the group consisting of alkoxy groups having 1 to 8 carbon atoms and cycloalkoxy groups with 5 to 8 carbon atoms, and R1 is selected from the group consisting of substituted or unsubstituted alkylene group having a total of 1 to 18 carbon atoms and a substituted or unsubstituted arylene group having from 6 to 12 carbon atoms or

Description

II.

PROCESS FOR THE PREPARATION OF A COMPOSITION OF REFORZ RUBBER DO IN PARTICLES FIELD This invention relates to the preparation of rubber compositions containing silica reinforcement and utilizing non-symmetrical organosulfide disulfide copolymer. The invention also relates to the preparation of plates having treads made with the above compositions.

BACKGROUND OF THE INVENTION For various applications that use rubber that requires high resistance to abrasion and resistance, particularly applications such as tires and various industrial products, sulfur-cured rubber containing substantial amounts of particulate fillers is used. Carbon black is commonly used for that purpose and usually provides or improves the good physical properties for the sulfur-cured rubber. Additional types of fillers in paints commonly used in rubber include silica, alumina and uminosi 1 icado. It is important to note that, conventionally, carbon black is a considerably more effective reinforcing filler for rubber products and particularly rubber rubber tire bands than silica unless silica is used in conjunction with a rubber reinforcing agent. copulation, which can sometimes be referred to as a silica coupler or silica adhesive compound or coupling agent. Numerous coupling agents are taught for use in combining silica and rubber, such as, for example, silane-containing agents containing a polysulfide component or structure in which the polysulfide bridge portion can be composed of from 2 to 8. sulfur units, such as for example an organosilane polysulphide sometimes referred to as bis- (3- triethoxy isi 1propanol), available from Degus GmbH, for example, as S i 69. It is understood that the Sulfur bridge portions of said "tetrasulfide", while having an average of about 3.5 to about 45 atoms of sulfur connection, actually have about 2 to about 6 or 8 sulfur atoms connecting in their Pute portions where no more than 25 percent of their bridge portions contain two connecting sulfur atoms. Therefore, it is hereby considered that at least 75 percent of the sulfur bridge portions contain three or more sulfur connecting atoms. For example, see United States Patents 4,076,550, 4,704,414 and 3,873,489. It is recognized that said organosilane polysulfides containing three or more connecting sulfur atoms in their sulfur bridges can also act as a sulfur donor for liberation of free sulfur to participate in a vulcanization or partial vulcanization of an elastomer vulcanizable with sulfur. since the free sulfur can be released there from a temperature, for example, of about 150 ° C and above. It is hereby stated that said temperature is close in nature and depends on a choice of various individual organosilane polysulfides as well as other factors, even when it is believed that at temperatures below about 150 ° C for more practical organosilane polysulfides than With three to eight sulfur atoms in their sulfur bridge portions, the release of free sulfur, if any, occurs in a slow relativve regime. These temperatures can be experienced, for example in preparation or what is often referred to as the non-productive mixing stage for rubber mixing and the rubber setting ingredients, typically exclusive of the addition of free sulfur, sulfur donors and / or accelerators. of vulcanization of rubber. This mixing could typically occur, for example, a temperature on a scale of up to about 150 B C to about 180 C; and more likely at least a portion of the mixture occurs at a temperature of at least 160 Q or more. A small amount of free, light sulfur is then available for blending with and / or possibly partially vulcanizing the unsaturated elastomer with which the silica and coupler are being mixed in said mixing steps.

U.S. Patent 4,820,751 discloses a rubber tire position containing a particular surface-treated carbon black, silica, and silica coupling agents of the formula wherein m and n is an integer from 1 to 6 and Y is an alkyl group or alkoxy group having from 1 to 4 carbon atoms.

SUMMARY AND PRACTICE OF THE INVENTION In accordance with one aspect of this invention, a rubber composition is made by a process comprising the sequential steps of: (A) mixing thermo-mechanically on at least one preparatory mixing pad at a temperature around from 1409 to about 1 0 QC, during a total mixing time of about 2 to about 20 minutes (i) 100 parts by weight of at least one elastomer vulcanizable with sulfur selected from conjugated diene homopolymers and copolymers and copolymers of at least one conjugated diene and composed of aromatic nyl; (ii) from about 15 to about 100 phr of particulate filler selected from the group consisting of precipitated silica, alumina, aluminosilicate, carbon black, and mixtures thereof; (iii) about 0.05 about 20 parts by weight per part by weight of the filling < in particles of at least one non-symmetrical organo silicon disulfide compound having the formula: where Z is selected from the group consisting of wherein R can be the same or different and is independently selected from the group consisting of alkyl group having 3 to 1 carbon atoms and phenyl; R may be the same or different and is independently selected from the group consisting of alkoxy groups having from 1 to 8 carbon atoms, cycloalkoxy groups with 5 to 8 carbon atoms; and R is selected from the group consisting of a substituted or unsubstituted alkylene group having a total of 1 to 18 carbon atoms and a substituted or unsubstituted arylene group having a total of 6 to 12 carbon atoms; and (iv) at least one sulfur donor having a property to release at least a portion of sulfur at a temperature of a scale of about 140 ° C to about 190 ° C and selected from the group consisting of elemental sulfur, a disulfide of amine, p-polymeric lysulfide and sulfur olefin adducts; provided, however, that the total sulfur free of 11 to addition of sulfur donor is on a scale of about 0.05 to about 2 phr; and (B) subsequently mixing with the same, in a final thermomechanical mixing step, at a temperature of about 100 ° C to about 140 ° C for a time of about 1 to about 3 minutes, of about 0.4 to about 3 phr. of elemental sulfur, provided, however, that the total free sulfur available from the addition of sulfur donor introduced in the preparatory mixing steps and the elemental sulfur added in the final mixing step is on a scale of about 0.45 to approximately 5 phr.

Detailed Description 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 prescribed. Terms such as "rubber composition", "rubber compound" and "rubber compound", if used herein, are used interchangeably to refer to rubber that has been mixed with various ingredients and materials and "composition". "rubber", or "composition" can be used to refer to the mixing of said materials. These terms are well known to those who have experience in the field of rubber mixing or rubber composition. In the practice of this invention, as noted above, the rubber composition is comprised of at least one diene-based elastomer or rubber. Suitable conjugated dienes are isoprene and 1,3-butadiene and appropriate vinyl aromatics are styrene and alpha methyl styrene. Thus, it is considered that the elastomer is a curved elastomer with sulfur. Said elastomer based on diene, or rubber, may be selected, for example, from at least one of cis 1, 4-poly isoprene (natural and / or synthetic) box, and preferably natural rubber) , styrene / butadiene copolymer rubber not prepared by emulsion polymerization, styrene / butadiene rubber prepared by polymerization of organic solution, 3, 4-pol ii soprene rubber, isoprene / butadiene rubber / styrene terpolymer rubbers / isoprene / butadiene, cis 1,4-p libutadiene, medium vinyl polybutadiene rubber ('35 -50 percent vinyl), high vinyl polybutadiene rubber (50 75 percent vinyl), styrene copolymers / The solvent was prepared from the styrene / butadiene / acrylonitrile terpolymer prepared by emulsion polymerization and butadiene copolymer rubber / acrylonitrile. 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 about 28 percent of bound styrene, or for some applications, a E-SBR having a medium to relatively high content of styrene bound, ie, a bound styrene content of from about 30 to about 45 percent. A relatively high styrene content of about 30 to about 45 for the E-SBR could be considered beneficial for a purpose of improving the traction, or slip resistance, of the tire tread. The presence of the E-SBR itself is considered beneficial for the purpose of improving the processability of the uncured elastomer composition mixture, especially as compared to a SBR use prepared by solution polymerization (S-SBR). . By means of E-SBR prepared by emulsion polymerization it is implied that styrene and 1,3-butadiene is copolymerized as an aqueous emulsion. These are well known to those experienced in said technique. The styrene ligad content may vary, for example, from about 5 to 50 percent. In one aspect, the E-SBR may also contain acrylonitrile to form a terpolymer rubber, such as E-SBR, in amounts, for example, from about 2 to about 30 percent based on acrylonitrile bound in the terpolymer. Styrene / butadiene / acrylonitrile terpolymer rubbers prepared by emulsion polymerization containing from about 2 to about 40 weight percent bound acrylonitrile in the thermopolymer also contemplated how diene based rubbers for use in this invention. The SBR prepared by solution polymerization (S-SBR) typically has a bound styrene content on a scale of about 5 to about 50, preferably about 9 to about 36 percent. The S-SBR can be conveniently prepared, for example by organolithium catalysis in the presence of an organic hydrocarbon solvent One purpose of using S-SBR is for improved rim rolling resistance as a result of lower hysteresis when used in a tire tread band composition. The rubber of 3,4-pol i and soprene (3,4-PI) is considered basic for a purpose of improving the traction of the rim when it is used in a flat tread composition.

The elastomer of 3, 4-pol i and soprene and the use thereof is more fully described in U.S. Patent No. 5,087,668 which is incorporated herein by reference. The cis 1,4-polybutadiene rubber is considered to be beneficial for a purpose of improving rim band wear, or tread wear. This polybutadiene elastomer can be prepared, for example, by polymerization of organic solution of 1,3-but-diene as is well known to those having experience in that field. The polybutadiene elastomer can be conveniently characterized, for example, by having at least 90 percent cis 1,4- content. Cis 1, 4-polyisoprene and the natural rubber of cis 1, polyisoprene are well known to those having experience in the rubber industry. A reference to an elastomer Tg, if used herein, refers to a glass transition temperature which can be determined by a differential scanning calorimeter at a heating rate of 10 SC per minute. The procedure of the present invention involves the use of 15 to about 100 phr of particulate filler is read from the group consisting of silica precipitated alumina, aluminosilicate, carbon black and mixtures thereof. The vulcanized rubber composition should contain a sufficient amount of particulate filler to contribute to a reasonably high modulus and high tear strength. The combined weight of silica, alumina, aluminosi 1 icatos and carbon neg, as mentioned above, can be as low as about 15 phr, but more preferably is about 35 to about 90 phr. . Even though it is hereby considered that the commonly employed silicious pigments used in rubber composition applications could be used as the silica in this invention, including pyrogenic silicate pigments and precipitates (silica) alumina, light and silicas, precipitated silicas. I prefer. The silicious pigments preferably used in the invention are precipitated silicas, such as, for example, those obtained by the acidification of a soluable silicate, e.g., sodium silicate. These precipitated silicas are well known to those who have experience in said ram These precipitated silicas could be characterized, for example, by having an area. BET surface, 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 30 (1930). The silica can also typically be characterized as having an abostion value of dibutyl phthalate (DBP) on a scale from about 1V00 to about 350, and more usually from about 150 to about 300.

In addition, the silica, as well as the aforementioned alumina and aluminosi 1 can be expected to have a surface area CTAB on a scale of about 100 to about 220. The CTAB surface area is the external surface area as evaluated by cetyl trimeti-lamonium bromide with a pH of 9. The method is described in AST D 3849 for adjustment and evaluation. The CTAB surface area is a well known means for characterizing the silica. The surface area of mercury / porosity is the specific surface area determined by Mercosur porosimetry. For this technique, the mercury is made to penetrate into the pores of the sample after a term treatment to eliminate volatiles. Adjustment conditions can be described as quickly as using a sample of 100 mg; eliminating the volatile for 2 hours at 1059C and atmospheric pressure, the pressure measurement scale is ambient at 2000 bars. This evaluation can be carried out in accordance with the method described in Winslow, Shapiro in ASTM bulleting, p.39 91959) or in accordance with DIN 66133. For this evaluation, a 2000 CARL0-ERBA Po meter can be used. The specific surface area of average mercury porosity for silica should be on a scale of approximately 100 to 300 square meters / gram. A proper pore size distribution for the slate, alumina and aluminosilicate in accordance with said mercury porosity evaluation is hereby considered that five percent or less of its pores have a diameter of approx. 10 nm; 60 to 90 percent of its pores have a diameter of about 10 to about 100 nm; 10 percent of its pores have a diameter of about 100 about 1000 nm; and 5 to 20 percent of its pores have a diameter greater than approximately 1000 nm. It could be expected that the silica would have an average final particle size, for example, on a scale of 0.01 to 0.0 microns as determined by the electron microscope, 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 in the present, and without limitation, silicas commercially available from PPG Industries under the trademark Hi-Sil co designations Hi-Sil 210, 243, EZ. , etc; available silicas from Rhone-ßoulenc, with for example, designation of Zeosi (R) '1165MP silicas available from Degussa GmbH with, for example, designations VN2, VN3, BV33806R, etc., and commercially available silicas of Huber having , for example, a designation of Huber 8745. Representative examples of alumina for the purposes of this invention are natural and synthetic aluminum oxide (Al 203). This alumina can be prepared synthetically in 1.4 suitable, for example, by controlled precipitation of aluminum hydroxide. For example, A 1"03 neutral, acidic and basic can be obtained from the Aldrich Chemical Company. In the practice of this invention, natural alumina is preferred; however, it is considered here that the acidic, basic and neutral forms of alumina could be used. The neutral or substantially neutral form is indicated as being preferential in order to use a form with reduced number of -OH surface groups in comparison with the acidic form and, also, to reduce the basic sites of the alumina are ions of A10. , which represent a strong base, in order to reduce potential interferences with the desired reactions of the alumina with the organ disulfide coupler. Representative examples of aluminosilicates for the purposes of this invention are, for example, but not intended to be limited to Sepiolite as a natural aluminosilicate (R) which could be obtained as PANSIL ™ from tolsa, SA, Toledo , Espa (R) ña, and SILTEG 'as an aluminosi 1 icato synthetic de Degussa Gmb These aluminosilicates can be used as natural materials or synthetically prepared, for example, as exemplified above. When it is desired that the rubber composition, which has both a silicious filler such as silica, alumina and / or minosite and also carbon black as reinforcing pigments, is reinforced primarily with silica as the strength pigment. , it is often preferable that the weight ratio of said silica silicate pigments to carbon black be at least 3/1 and preferably at least 10/1, and on this scale, on a scale of about 3 / 1 to approximately 30/1. The filler is comprised of from about 15 to about 95 weight percent precipitated silica, alumina, and / or the like, and, correspondingly, from about 5 about 85 weight percent carbon black; in d of the carbon black has a CTAB value on a scale of about 80 to about 150. Preferably, the filler may be comprised of from about 60 to about 95 weight percent of the silica, alumina and / or or aluminum 1, and correspondingly, from about 40 to about 5 weight percent carbon black. Representative organosulfide disulfide compounds according to the present invention include 2-bentozitazi 1 - (3-triethoxy if 1 i 1) propyl disulfide; 2-benzothiazyl disulfide l- (2-trimethoxysi 1 i leti lo); 2-benzothiazine 1 93-trimethoxy si 1 disulfide 1product); 2-benzothiazyl disulfide l- (2-triet xisi 1 i l propyl); 2-benzothiazi disulfide 1 - (2-tripropoxy si 1 i 1 ethyl); 2-benzothiazi disulfide 1 - (2-tri-sec-butoxisi 1 i leti lo) 2-benzothiazi disulfide 1 - (2-tr i -t-butoxy si 1 i let i lo); disulfu of 2-benzothiazl- (3 ~ tri i sopropoxisi 1 i lpropi lo); 2-benzothiazine disulfide 1 - (3-triocotxy if 1 -propylo); 2-benzothia disulfide zi 1 - (2-2 '-eti lhexoxisi 1 i leti lo); 2-benzothiazide disulfide 1- (2-dimethoxy ethoxy si 1 i leti lo); 2-benzothiazyl disulfide l- (3-methoxy ethoxypropoxy si 1 i-propyl); disulfide of 2-benzothiazyl- (3-dimethoxyeti 1 s i 1 1propy); 2-benzothiazie disulfide 1 - (3-methoxy dimethyl if 1 i 1 propi lo); 2-benzothiazine disulfide 1-93-diethoxyeti 1 s i lylpropyl); 2-benzothiaz i 1 - (3-ethoxydimeti lsi 1 ipropro) disulfide; 2- (Benzothiazyl 1 - (3-cyclohexoxy dimeti 1 Si 1 i 1 propyl) disulfide 2-benzothiazi disulfide 1- (4-trimethoxy si 1 i butyl) 2-benzothiazi disulfide 1- (3-trimethoxy) Si 1 i 1-3-meti lpropi lo), 2-benzothiazi disulfide 1 - (3-tri-propoxy 1 i -3-methyl-1-propylene) 2-benzothiazine di-1 -93-dimethoxy meti 1 if 1 i 1 -3-eti 1 propi lo); 2-benzothi azi 1 - (3-tr imethoxy si 1 i 1 -2-methypropylo) disulfide; d 2-benzothiazyl sulfide 1 - (3-dimethoxypheni 1 si 1 i 1-2-met i lpropi lo); 2-benzothiazie disulfide 1 - (3-trimethoxy s i 1 i1cyclohexy lo); disul furo 2-benzothiazl- (12-tr imethoxysi 1 i ldodeci lo); 2-benzothiazyl disulfide l- (12-trietoxisi 1 i ldodeci lo); disulfide of 2-benzo thiaz i 1 - (18-trimethoxy si 1 i loctadeci lo); 2-benzothiazi disulfide (18-methoxydimeti 1 si 1 i loctadeci lo); 2-benzothiazi disulfide 1 - (2-trimethoxysi 1 i 1-2-meti leti lo); 2-benzothiazi disulfide 1 - (2-tripropoxy si 1 i 1-2-meti leti lo); 2-benthotiazi disulfide 1 - (2-trioctoxy si 1 i 1-2-meti leti lo); disulfide of 2-ben2otiazi 1 - (2-tri methoxy si 1 i 1-pheni lo); 2-benzothiazi disulfide 1- (2-trietoxisi 1 i phenyl); 2-benzothi azi 1 - (2-trimethoxy si 1 i 1 -tol i lo disulfide); 2-benzothiaz disulfide i 1 - (2-trietoxisi 1 i 1-tol i lo); 2-benzothiazie disulfide 1 - (2-tr imethoxysi 1 i 1 -methyl-1-tolyl); disulfide of 2-benzothiazine 1 -92-triethoxy si 1 i 1-methy1 tolyl); disulfide of 2-be zotiazi 1 - (2-tr imethoxy s i 1 i 1 -eti 1 phenyl); 2-benzothia zi disulfide 1- (2-triethoxysi 1 i 1 -eti 1 phenyl); 2- (benzothiazyl-1, -92-trimethoxy-1-1-ethyl-1-tolyl) disulfide; 2-benzothiazide disulfide 1 - (2-triethoxy si 1 i 1 -ethi 1 tolyl); 2-benzothiazi disulfide 1- (3-tr imethoxy si 1 i 1-propi 1 phenyl); 2-benzothiazie disulfide 1 - (3-trietoxyl silyl-propyl phenyl); 2-benzothiazi disulfide 1 - (3-trimethoxy if lyl-propyl tolyl); and disulfide of 2-benzot iazi 1 - (3-triethoxy if 1 i 1-propi 1 tol i lo). With reference to the above formula, preferably R is an alkylene group having 1 to 3 carbon atoms R-3 3 and R is an alkoxy group having from 1 to 3 carbon atoms. The non-symmetrical organosulfide disulfide compounds used in the present invention can be prepared by reacting (a) a sulfenamide compound of the formula wherein R is selected from the group consisting of hydrogen, acyclic aliphatic groups having from 1 to 10 carbon atom and cyclic aliphatic groups having from 5 to 10 at 5 carbon atoms; and R is selected from the group consisting of acyclic aliphatic groups having from 1 to 10 carbon atoms and cyclic aliphatic groups having from 5 to 10 carbon atoms; with (b) a mercaptosis compound of the formula Z-R -SH where Z is selected from the group consisting of wherein R may be the same or different and is independently selected from the group consisting of an alkyl group 3 having 1 to 4 carbons and phenyl; R may be the same or different and is independently selected from the group consisting of alkoxy groups having from 1 to 8 carbon atoms and cycloalkoxy groups with 5 to 8 carbon atoms; and R is selected from the group consisting of a substituted or substituted alkylene group having a total of 1 to 18 carbon atoms and a substituted or unsubstituted arylene group having a total of 6 to 12 carbon atoms. .49 Representative examples of sulfenamide compounds include N-cyclohexy 1 -2-benzothiazine 1 sulfenamide, Nt-butyl 1-2-benzothiazyl sulfenamide, N, N-dicyclohexyl-2-benzothiazyl sulfenamide N- i sopropil-2-benzothiazine 1 Sulfenamide, N, N-dimethyl-2-benzothiazine sulfenamide, N, N-diet i 1-2-benzothiazyl sulfenamide, N, Nd i prop i 1 -2 benzothiaz i 1 sulfenamide, N.NOdi i sopropil-2-benzothiazil -sulfenamid and N, N-dipheni 1 -2-benzothiaz i lsulfenamide. Preferably, the sulfonamide is N-cyclohexy 1 -2-benzothiazine 1 sulfenamide. Representative examples of mercapto silane compounds include 2-mercaptoet i 1 trimethoxy si 1 yl, 3-mercaptopro pyltrimethoxy si 1 yr, 3-mercaptopropi 1 trietoxy si tin, 2-mercapto propyl triethoxy si tin, 2-mercaptoeti 1 tripropoxy if 1 year, 2-mercap toethyl tri-sec-butoxy if tin, 3-mercaptopropi 1 tri-t-butoxy if lañ 3-mercaptopropi 1 tri isopropoxi si láño; 3-mercaptopropi 1 triooct xisilano, 2-mercaptoet i 1 tr i - V -et i lhexoxi si 1 ano, 2-mercaptoet i 1 dimethoxy siño, 3-mercaptopropi 1 methoxyethoxy propoxisi ño, 3-me captopropyl dimethoxy meti 1 si láño , 3-mercaptopropi 1 methoxy dimeth silane, 3-mercaptopro and 1 diethoxy methylsilane, 3-mercaptopropi 1 ethoxy dimethyl lithium 3-mercaptopropi 1 cyclohexoxy dimethyl silane, 4-mercaptobutyltrimethoxysilane, S-mercapto-S-methylpropyltrimetha silane, 3-mercapto- 3-rt? Eti lpropi 1 -tripropoxy siño, 3-mercapto-3-eti lpropi 1-dimethoxy methylsilane 3-mercapto-2-meti lpropi 1 trimethoxysilane, 3-mercapto-2-methy1 propi 1 dimethoxy phenylsilane, 3 -merc to c ic lohexi 1 -tr imethoxy if 1 year, 12-mercaptododeci 1 trimethoxy sil no, 12-mercaptododeci 1 trietoxi silano, 18-mercaptooctadeci 1 tri metoxisiñoño, 18-mercaptooctadeci 1 ethoxydimeti 1 si 1 ano, 2-mercap to-2-meti leti ltripropoxi si líno, 2 -mere apt -2 -met i letil-trioctoxi silano, 2-mercaptofeni 1 tr imethoxi si láño, 2-mercaptof in i 1 trietox silane, 2-mercaptotol and 1 trimethoxysilane; 2-mercaptotol i 1 trieto xisilano; 2-mercaptomethyl ltol i 1 trimethoxysilane; 2-mercaptomethyl tolyl trietoxisi laño; 2-mercaptoeti lfeni 1 tr imethoxy if 1 year; 2-mercaptoeti lfeni 1 trietoxy s i tin; 2-mercaptoeti lfeni 1 trietoxis laño; 2-mercaptoeti 1 tol i 1 trimethoxy if tin; 2-mercaptoeti ltol i 1 trietoxis i 1 year; 3-mercaptopropi lfeni 1 trimethoxy if tin; 3-merca topropi lfeni 1 trietoxi si 1 ano; 3-mercaptopropyl ltol i 1 trimethoxysi lano; and 3-mercaptopropyltol i 1 trietoxi si 1 ano. The molar ratio of the sulfenamide compound to the mercaptoside compound can vary from 1: 5 to 5: 1. Preferably, the molar ratio varies from 1: 3 to 3: 1 with a scale of 1: 1 1: 2 being particularly preferred. As can be seen from the teachings herein, varying the molar ratio of the compound of the formula III to the compound of the formula IV produces variable weight percentage of the symmetrical organosilicon disulfide of the formula I and the organophosphide disulfide. symmetric n of formula II. The reaction must be conducted in the absence of water due to the presence of an alkoxysilane fraction which can be hydrolyzed by contact with water. The reaction can be conducted in the presence of an organic solvent. Suitable solvents that can be used include cloform, dichloromethane, carbon tetrachloride, hexane, heptane, cyclohexane, xylene, benzene, dichloroethane, ethylene trichloride, dioxane, diisopropyl ether, tetrahydrofuran and toluene. As indicated above, care must be taken to avoid the presence of water during the reaction. Therefore, none of the antecedent solvents should contain any appreciable levels of water. Preferably the organic solvent is chloroform, heptane, xylene, cyclohexane or toluene. The reaction can be conducted through a variety of temperatures. Geney speaking, the reaction is conducted at a temperature ranging from 20 ° C to 140 ° C. Preferably, the reaction is conducted at a temperature ranging from 50 ° C to 90 ° C. The reaction can lead to a variety of pressures. Geney speaking, however, reaction s 2 leads to a pressure that varies from 0.096 to 4.83 kg / cm. The organophosphorus disulfide compounds may also be prepared by the following reaction scheme: or the reaction scheme In the practice of the invention, at least one sulfur donad having a property of releasing at least the sulfur potion at a temperature on a scale of about 140 ° C to about 190 ° C is used in a preparatory step. When the amount of sulfur donor introduced into the mixing preparation is generally on a scale of about 0.05 to about 2 phr, preferably about 0. to about 1 phr. This sulfur donor can be, for example, in a form of elemental sulfur (S8), or an anamin disulfide, polymeric polysulfide, sulfur olefin adducts and mixtures thereof. Preferably, the sulfur donor is elemental sulfur.

The amount of free sulfur source addition to the mixture can be controlled or manipulated as a matter of choice of amine relatively independent of the addition of the unsymmetrical organ disulfur. In this way, for example, the independent addition of sulfur donor can be manipulated by the amount of addition thereof and by addition sequence in relation to the addition of other ingredients to the rubber mixture such as, for example, the silica reinforcement. Thus, then, the symmetrical n-organosilane disulfide, with its two connecting sulfur atoms, could be used for reaction with the silica and vulcanizable elastomer with sulfur and the independent addition of the sulfur donor, particularly a source of free sulfur. , it could be based mainly during the vulcanization of the elastomer. In one aspect of the invention, said process is provided, wherein the preparation mixing is conducted in at least two thermomechanical mixing steps of which at least two of said mixing steps are at a temperature on a scale of about 140 ° C to about 190 ° C, with intermediate cooling of the rubber composition between at least two of the mixing steps at a temperature of less than about 50 ° C. In additional accordance with this invention, a rubber composition is prepared in which the preparation steps (A) are composed of at least two sequence mixing steps in which the elastomer, the particulate filler and the organosulfur disulfide compound. The non-symmetrical operation is mixed in one or more sequential mixing steps and wherein the sulfur donor is added in a subsequent sequential preparation mixing step. In further accordance with another embodiment, a rubber composition is prepared wherein the preparation steps (A) are composed of at least two sequential mixing steps in which from about 20 to about 60 weight percent of the The silica, the unsymmetrical organo silicon disulfide compound and the sulfur donor are added in the first mixing step and the remainder is added in at least one mixing step of subsequent preparation. According to another embodiment, the non-symmetrical disulfide of nosilicon is optionally added to the thermomechanical pretreatment mixture in a form of a particle comprised d (a) of from about 25 to about 75, preferably from about 40 to about 60, weight percent of the non-symmetrical organosilane polysulphide compound, and correspondingly, (b) from about 75 to about 25, preferably from about 60 to about 40, percent by weight of carbon black in particles. An advantage of this embodiment is to provide the unsymmetrical organosulfide disulfide in a particulate form so as to add the unsymmetrical organosulfide disulfide in a relatively dry, or substantially dry, powder form in that the carbon black is acted as a carrier for the non-symmetric organophosphide disulfide since it is considered herein that non-symmetrical organosilane disulfide would otherwise be a liquid, or substantially liquid. One benefit with tempering for the particle is to assist in the dispersion of the dissymmetry of non-symmetrical organosis in step 9) of pre-processing mixing of the process of this invention and to assist in the introduction of the non-symmetrical organosulfide disulfide into the mixture. p paratorium of the rubber composition mixture. In additional accordance with the invention, the process comprises the additional step of vulcanizing the prepared rubber composition at a temperature on a scale of about 140 ° C to about 190 °. Consequently, the invention also contemplates in this manner the vulcanized rubber composition prepared by said process. In further accordance with the invention, the process comprises the additional steps of preparing a set of a rim or vulcanizable rubber with sulfur with a rolling band comprised of the rubber composition prepared in accordance with the process of this invention and vulcanizing the rubber. set at a temperature on a scale of about 1405C to about 190QC. Consequently, the invention also contemplates in this way a vulcanized rim prepared by said process It is readily understood by those of ordinary skill in the art that the rubber composition may additionally contain various commonly used additive materials such as, for example, curing aids, such as sulfur, activators, retarders and accelerators, processing additives, such as oil, resins including tackifying resins, plastics, pigments, fatty acid, zinc oxide, waxes, antiox dnates and antiozonants and peptizing agents .. As is known by those experienced in the field, depending on the inte With the addition of sulfur-curable vulcanizable Ateral and Vulcanized with sulfur (rubber), the aforementioned additives are commonly selected in conventional amounts. Typical amounts of carbon black (s) of type d reinforcement, for this invention, if used, are set forth 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 range from about 1 to about 50 phr. These processing aids may include, for example, aromatic, naphthenic and / or paraffinised process oils. Typical amounts of anitoxidants comprise from about 1 to about phr. Representative antioxidants may be, for example, diphenyl-1-p-phenylenediamine and others, such as, for example, those described in the Vanderbilt Rubber Handbook (1978), pages 344-346. Typical amounts of antiozonants comprise from about 1 to 1 phr. Typical amounts of fatty acids if used, which may include stearic acid, comprise from about 0.5 to about 3 phr. Typical amounts of zinc oxide comprise from about 2 to about phr. The amounts of typical waxes comprise from about d 1 to about 5 phr. Often my crossover waxes are used. Typical amounts of peptizers comprise from about 0.1 to about 1 phr. Typical peptizing agents can be, for example, pentachlorothiophenol and di-1-di-benzamidodiphenol. The vulcanization is conducted in the presence of a sulfur vulcanization agent. Examples of suitable sulfur vulcanizing agents include, for example, sulfur element (sulfur free) or sulfur donating vulcanization agents, for example, an amine disulfide, polymeric polysulfide or sulfur olefin adducts which are conventionally added in the final mixing composition of rubber, productive. 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 productive mixing stage, in an amount ranging from about 0.4 to about 3 phr, or even, in some circumstances, up to about 8 phr, with a scale of about 1.5 to about 2.5, in occasions from 2 to 2.5, being usually 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, ie, a 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 the primary and secondary accel- erator could be used with the secondary accelerator being used in smaller quantities (from 0.05 to about 3 phr) to activate and improve the properties of the vulcanizate. The combinations of these aclerators could be expected to produce a synergistic effect on the final properties and are somewhat better than those produced by the use of any single accelerator. further, the delayed action accelerators can be used which are not affected by the processing temperatures, but which produce a satisfactory cure at ordinary vulcanization temperatures. Vulcanization retarders could also be used. The appropriate types of accelerators that can be used in the present invention are amines, disulfides, guanines, thioureas, thiazoles, thiurams, sulfenamides, dithiocarbamate and xanthates. Preferably, the primary accelerator is a sulfonamide. If a second accelerator is used, the secondary accelerator is preferably a guanidine, di thiocarbamate or riuram compound. The rubber composition of this invention can be used for various purposes. For example, it can be used for various rim compounds. These tires can be constructed, molded and cured by various methods that are known and will be readily apparent to those who have experience in the field. Although certain representative embodiments and details have been described for the purpose of illustrating the invention, it will be apparent to those skilled in the art that various changes and modifications may be made therein without abandoning the spirit or scope of the invention.

Claims (10)

CLAIMS:

1. - A process for preparing a rubber composition characterized by the sequential steps of: (A) mixing thermomechanically in at least one preparatory mixing pass at a temperature of about 1405 C to about 190 QC for a total mixing time of from about 2 to about 20 minutes, (i) 100 parts by weight of at least one elastomer vulcanizable with sulfur selected from homopolymers and copolymers of conjugated diene and copolymers of at least one conjugated diene and aromatic vinyl compound; (ii) from about 15 to about 100 phr of particulate filler selected from the group consisting of precipitated silica, alumina, uminisi 1 icato, carbon black and mixtures thereof; (iii) about 0.05 about 20 parts by weight per part by weight of the particulate filler of at least one non-symmetrical organo silicon disulfide compound having the formula: 1-Z wherein Z is selected from the group consisting of wherein R may be the same or different and is independently selected from the group consisting of an alkyl group 3 having 1 to 4 carbons and phenyl; R may be the same or different and is independently selected from the group consisting of alkoxy groups having 1 to 8 carbon atoms and 1 cycloalkoxy groups with 5 to 8 carbon atoms; and R is selected from the group consisting of substituted or unsubstituted alkylene group having a total of 1 to 18 carbon atoms a substituted or unsubstituted arylene group having a total of 6 to 12 carbon atoms; and (iv) at least one sulfur donor having a property of releasing at least a portion of sulfur at a temperature on a scale of about 140 QC to about 190 QC and selected from the group consisting of elemental sulfur, an amine disulfide, polymeric polysulfur and adducts of sulfur olefin; as long as, however, that the total sulfur free addition of sulfur donor is on a scale of about 0.05 to about 2 phr; and (B) subsequently mixing with it, in a final thermomechanical mixing pass at a temperature of about 100 QC to about 130 BC for a time of about 3 minutes, from about 0.4 to about 3 phr of sulfur. elementary, as long as, however, that the total free sulfur introduced in the mixing steps p paratorios and the elemental sulfur added in the final mixing step is on a scale of about 0.45 to about 5 phr.

2. The process of claim 1, characterized in that the preparatory mixing is conducted in at least two periods of thermomechanical mixing, wherein at least two of said mixing steps are at a temperature of about 14 C to approximately 190QC, with cooling intermediate the rubber position between at least two of the mixing steps at an infertory temperature of approximately 50 ° C.

3. The process of claim 1, which is characterized by the additional step of vulcanizing the prepared cacao composition at a temperature on a scale of about 140 QC approximately 190SC.

4. A vulcanized rubber composition is charged by which is prepared in accordance with the r vindication process? 3.

The process of claim 1, which is characterized by the additional steps of preparing a set of a rubber rim vulcanizable with sulfur with a tread band comprised of the rubber composition and vulcanizing the whole a temperature on a scale of around 140 QC approximately 190QC.

6. - A vulcanized rubber tire is characterized in that it is prepared according to the process of claim 5.

7. The process of claim 1, characterized in that the elastomer vulcanizable with sulfur is selected from at least one cis rubber 1, 4-pol ii natural and synthetic soprene, styrene / butadiene copolymer rubber prepared by emulsion polymerization, styrene-butadiene copolymer rubber prepared by polymerization of organic solution, 3, 4-pol ii soprene, isoprene rubber / butadiene, styrolne / i soprene / butadiene terpolymer rubbers, cis 1,4-polybutadiene rubber, medium v-vinyl polyvinyl rubber (35-50 percent vinyl), high vinyl polybutadiene (50-75) percent vinyl) and styrene / butadiene acrylonitrile terpolymer rubber prepared by emulsion polymerization and butadiene / acrylonitrile copolymer rubber.

8. The process of claim 1, characterized in that the silica is characterized in that it has a BET surface area on a scale of about 100 to about 300 meters per gram and an absorption value of dibutyl phthalate (DBP). on a scale of about 150 to about 350, CTAB value on a scale of about 100 to about 220, and a pore porosimetry pore size distribution of 5 percent less than its porous with a diameter of less than of approximately 10 nm; 60 to 90 percent of its pores with a diameter of about 10 to about 100 nm; 10 to 30 percent of its pores with a diameter of about 100 to about 1000 nm and 5 to 20 percent of its pores with a diameter greater than about 1000 nm.

9. The process according to claim 1, characterized in that the particulate filler comprises from about 15 to about 95 percent by weight of precipated silica and, correspondingly, from 5 to about 85 percent by weight of black. of coal; wherein the carbon black has a CTAB value on a scale of about 80 to about 150.

10. The process of claim 1, characterized in that the non-symmetrical organosulfide disulfide is selected from the group consisting of in 2-benzothiazi disulfide 1 - (3-tri ethoxysi 1 i 1) propi lo; 2-benzothiazyl l- (2-trimethoxy if 1 and ethyl) disulfide; 2-benzothiazine disulfide 1-93-trimethoxy si 1 ipropy); 2-benzothiazie disulfide 1 - (2-triethoxy si 1 ipropy); 2-benzothiazi disulfide 1- (2-tr ipropoxi si 1 i leti lo); 2-benzo tiazi disulfide l- (2-tri-sec-butoxisi 1 i leti lo); 2-benzothiazine disulfide 1 (2-tri-t-butoxisi 1 i leti lo); disulfide of 2-benzot iazi 1 -93-tri i s propoxy si 1 i propi lo); 2-benzothiazyl l- (3-triocotoxysylpropyl) disulfide; 2-benzothiazi disulfide 1 - (2, 2 '-eti lhexoxi si 1 i let it); 2-benzothiazi disulfide 1 - (2-dimethoxy ethoxy si 1 i leti lo); disulfide of 2-benzothi az i 1- (3-methoxyethoxypro- xviεi 1 ipropy); 2- (benzothiazyl 1 - (3-dimethoxymethyl 1 if 1-proton) disulfide; 2-benzothiazine disulfide 1 - (3-methoxy dimethyl 1 if 1 and 1 propyl); (3-diethoxymethi 1 if 1 1-propyl) 2-b-zoti-azi 1 - (3-ethoxydimeti 1 if 1 i 1 propi lo) disulfide 2-benzothia zi 1 - (3-cyclohexoxy dimeti 1 if 1 i 1 propi lo; 2-benzothi zi l- (4-trimethoxysi 1 i lbutyl) disulfide; 2-benzothiazi disulfide 1 - (3-tr methoxysi 1 i 1-3 -methylpropyl); benzothiazi- 1- (3-tri propoxy si 1 i 1-3-methy1 propyl); 2-benzothiazi disulfide 1- (3-di toxi eti 1 si 1 i 1 -3-ethylpropyl); -benzothiazyl 1 - (3-trimethoxysi 1 i 1-2 -methylpropane) 2-benzothiazole disulfide 1- (3-methoxypheni 1 if 1 i 1 -2-methylpropane) 2-benzothiazole disulfide 1 - (trimethoxysi 1 i1cyclohexylo), 2-benzothiazine disulfide 1 - (12-tri toxisi 1 iidode) lo, 2-benzothiazine disulfide l- (12-trietoxisi 1 dodecyl), 2-benzothiaz disulfide i 1 - ( 18-trimethoxy if 1 i loctade lo); 2-benzothiazi disulfide 1 - (18 -? ethoxydimeti 1 si 1 i loctadeci lo); disulfide of 2-benzot iazi 1 - (2-trimethoxysi 1 i 1-2-meti leti disulfide of 2-benzotiazi 1- (2-tripropoxy si 1 i 1-2-meti leti lo); d sulfide 2-benzotiazi l- (2-trioctoxisi 1 i 1-2-meti leti); disu furo of 2-benzotiazi 1- (2-trimethoxy si 1 i 1-phenylo); disulfide of 2-benzothiazi 1 - (2-trietoxy si 1-phenylenediol) 2- (benzot zi 1 - (2-trimethoxy if 1-1-tolyl) -disulfide of 2-benzothiazyl- (2-triethoxysi-1-1-tolyl) ); 2-benzothiazie disulphide 1 - (2-trimethoxy-1-methyl-methyl) 2-benzothiazole disulphide 1 - (2-triethoxysi-1-methyl-1-methylol); 2-benzothiazole-2-tributhoxy-1-disulfide 1-phenyl), 2-benzothiazi disulfide 1 - (2-trietoxisi 1 i 1 -eti 1 phenylo), 2-benzothiazi disulfide 1 - (2-trimethoxysi 1 i 1 -eti 1 tolyl) disulfide 2 -benzothiaz i 1 - (-trethoxy if 1 i 1 -eti 1 tolyl); disul furo of 2-benzothiaz 1 - (3-tr imethoxysi 1 i 1-propi 1 phenyl); disulphide of 1-benzothiaz 1 -93 -triethoxy if 1 i 1 -propi 1 phenyl); disulfide of 2-benzoti az i 1 = 3-tr imethoxy si 1 i 1 propyl tolyl); and disulfide d 2-benzothiazyl- (3-triethoxy si 1 i 1 -propi 1 tolyl).