CA2180887A1 - Silica reinforced rubber composition and tire with tread thereof - Google Patents
Silica reinforced rubber composition and tire with tread thereofInfo
- Publication number
- CA2180887A1 CA2180887A1 CA002180887A CA2180887A CA2180887A1 CA 2180887 A1 CA2180887 A1 CA 2180887A1 CA 002180887 A CA002180887 A CA 002180887A CA 2180887 A CA2180887 A CA 2180887A CA 2180887 A1 CA2180887 A1 CA 2180887A1
- Authority
- CA
- Canada
- Prior art keywords
- rubber
- silica
- tread
- rubber composition
- range
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/36—Sulfur-, selenium-, or tellurium-containing compounds
- C08K5/37—Thiols
- C08K5/372—Sulfides, e.g. R-(S)x-R'
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
- B60C1/0016—Compositions of the tread
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/54—Silicon-containing compounds
- C08K5/548—Silicon-containing compounds containing sulfur
Abstract
The present invention relates to a rubber composition containing silica reinforcement and to pneumatic tires having treads comprised of such rubber composition.
A rubber composition comprises at least one elastomer, silica, carbon black and a silica coupler comprised of 3,3'-tetrathiodipropanol polysulfide mixture.
A rubber composition comprises at least one elastomer, silica, carbon black and a silica coupler comprised of 3,3'-tetrathiodipropanol polysulfide mixture.
Description
`~ ~ 2180887 SII,ICA RRTMT~()R'Rn RTTRRRR CoMpos ITION
AND TIRE WITH TRRAn T~TRRROF
Field This invention relates to rubber compositions which contain silica reinforcement and to tires 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 bl~ck, and a 3, 3 ' -tetrathiodipropanol polysulfide mixture coupling agent .
BackcTround For various applications l1~;1;7;n~ rubber which requires high strength and abrasion resistance, particularly applica~ions such as tires and various industrial products, sulfur cured rubber is utilized which contains substantial amounts of reinforcing ~illers, often in a range of about 35 to about 85 parts by weight per 100 parts rubber. Carbon black is commonly used for ~uch purpose and normally provides or -nhAnroq good physical properties for the sulfur cured rubber. Particulate silica is also of ten used for such purpose, particularly when the silica is used in conjunction with a coupling agent. In some cases, a combination of silica and carbon black is utilized for reinforcing fillers for various rubber products, including treads for tires. The use of such reinforcing fillers for elastomers, including sulfur curable elastomers, is well known to those skilled in such art.
It is important to appreciate that, conventionally, carbon black is a considerably more effective reinforcing filler for ru~ber products, and particularly for rubber tire treads than silica if the silica is used without a coupling agent, or silica coupler or sllica adhesion agent as it may be sometimes referred to herein.
Such coupling agents may, for example, be 5 premixed, or pre-reacted, with the silica particles or added to the rubber mix during a rubber/silica processing, or mixing, stage. If the coupling agent and silica are added separately to the rubber mix during the rubber/silica mixing, or processing stage, 10 it i~ considered that the coupling agent then combines in situ with the 8ilica.
In particular, ~uch coupling agents are sometimes composed of a silane which has a constituent component, or moiety, (the silane portion) capable o~
15 reacting with the silica surface and, also, a constituent component, or moiety, capable of reacting with the rubber, par~ icularly a sul~ur vult~n; 7;~hl e rubber which c~nt;l;nq carbon-to-carbon double bonds, or unsaturation. In this manner, then the coupler 20 acts as a connecting bridge between the silica and the rubber and thereby f~nhi~nr~ the rubber reinforcement aspect of the silica.
In one a8pect, the silane o the coupling agent apparently forms a bond to the silica surface and the 25 rubber reactive ~ 7n~nt of the coupling agent combines with the rubber itself. Usually the rubber reactive component of the coupler is temperature sensitive and tends to combine with the rubber during the final and higher temperature sulfur vulcani2ation 30 stage and, thus, subsequent to the rubber/silica/
coupler mixing stage and, therefore, after the silane group of the coupler has combined with the silica.
However, partly because of typical temperature 8ensitivity of the coupler, some degree of 35 combination, or bonding, may occur between the rubber-reactive component of the coupler and the rubber 2 l 80887 during initial rubber/silica/coupler mixing stage (8) and, thus, prior to a subsequent vulcanization stage.
The rubber- reactive group component of the coupler may be, for example, one or more of groups such as mercapto, amino, vinyl, epoxy, and sulfur groups, and is often a sulfur or mercapto moiety and more usually sulfur.
Numerous coupling agents are taught for use in combining silica and rubber, such as, for example, silane coupling agents cnn~;n;n~ a polysulfide compone~t, or structure, such as, for example, ~r~lkn~ryorganosilane polysulfides containing from 2 to 8 sulfur atoms in a polysulfide bridge such as, for example, bis- (3-triethoxysilylpropyl) tetrasulfide and/or trisulf ide .
Various U.S. patents relating to silicas and silica reinforced tire treads include, for example, U.S. Patents Nos. 3,451,458; 3,664,403; 3,768,537;
AND TIRE WITH TRRAn T~TRRROF
Field This invention relates to rubber compositions which contain silica reinforcement and to tires 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 bl~ck, and a 3, 3 ' -tetrathiodipropanol polysulfide mixture coupling agent .
BackcTround For various applications l1~;1;7;n~ rubber which requires high strength and abrasion resistance, particularly applica~ions such as tires and various industrial products, sulfur cured rubber is utilized which contains substantial amounts of reinforcing ~illers, often in a range of about 35 to about 85 parts by weight per 100 parts rubber. Carbon black is commonly used for ~uch purpose and normally provides or -nhAnroq good physical properties for the sulfur cured rubber. Particulate silica is also of ten used for such purpose, particularly when the silica is used in conjunction with a coupling agent. In some cases, a combination of silica and carbon black is utilized for reinforcing fillers for various rubber products, including treads for tires. The use of such reinforcing fillers for elastomers, including sulfur curable elastomers, is well known to those skilled in such art.
It is important to appreciate that, conventionally, carbon black is a considerably more effective reinforcing filler for ru~ber products, and particularly for rubber tire treads than silica if the silica is used without a coupling agent, or silica coupler or sllica adhesion agent as it may be sometimes referred to herein.
Such coupling agents may, for example, be 5 premixed, or pre-reacted, with the silica particles or added to the rubber mix during a rubber/silica processing, or mixing, stage. If the coupling agent and silica are added separately to the rubber mix during the rubber/silica mixing, or processing stage, 10 it i~ considered that the coupling agent then combines in situ with the 8ilica.
In particular, ~uch coupling agents are sometimes composed of a silane which has a constituent component, or moiety, (the silane portion) capable o~
15 reacting with the silica surface and, also, a constituent component, or moiety, capable of reacting with the rubber, par~ icularly a sul~ur vult~n; 7;~hl e rubber which c~nt;l;nq carbon-to-carbon double bonds, or unsaturation. In this manner, then the coupler 20 acts as a connecting bridge between the silica and the rubber and thereby f~nhi~nr~ the rubber reinforcement aspect of the silica.
In one a8pect, the silane o the coupling agent apparently forms a bond to the silica surface and the 25 rubber reactive ~ 7n~nt of the coupling agent combines with the rubber itself. Usually the rubber reactive component of the coupler is temperature sensitive and tends to combine with the rubber during the final and higher temperature sulfur vulcani2ation 30 stage and, thus, subsequent to the rubber/silica/
coupler mixing stage and, therefore, after the silane group of the coupler has combined with the silica.
However, partly because of typical temperature 8ensitivity of the coupler, some degree of 35 combination, or bonding, may occur between the rubber-reactive component of the coupler and the rubber 2 l 80887 during initial rubber/silica/coupler mixing stage (8) and, thus, prior to a subsequent vulcanization stage.
The rubber- reactive group component of the coupler may be, for example, one or more of groups such as mercapto, amino, vinyl, epoxy, and sulfur groups, and is often a sulfur or mercapto moiety and more usually sulfur.
Numerous coupling agents are taught for use in combining silica and rubber, such as, for example, silane coupling agents cnn~;n;n~ a polysulfide compone~t, or structure, such as, for example, ~r~lkn~ryorganosilane polysulfides containing from 2 to 8 sulfur atoms in a polysulfide bridge such as, for example, bis- (3-triethoxysilylpropyl) tetrasulfide and/or trisulf ide .
Various U.S. patents relating to silicas and silica reinforced tire treads include, for example, U.S. Patents Nos. 3,451,458; 3,664,403; 3,768,537;
3,384,285; 3,938,~74; 4,482,663; 4,590,052; 5,089,554 and ~3ritish 1,424,503.
Various llydLu~yYIlfides have also been used to reinforce silica in carbon black filled rubber (EP
Patent Publication No. 489,313).
The term "phr" if used herein, and according to conventional practice, refers to "parts of a re8pective material l?er 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. The terms "rubber composition", "compounded rubber" and ~rubber compound", if used herein, are used interchangeably to refer to "rubber which ha8 been blended or mixed with various ingredients and materials" and such terms are well known to those ` ~ 2180887 having skill in the rubber mlxing or rubber compounding art.
A reference to an elastomer~ s Tg refers to its glasg transition temperature, which can converiently 5 be determined by a differential scanning calorimeter at a heating rate of 10C per minute.
SummarY and Practlce of the Tnv~nt;on In accordance with one aspect of this invention, 10 a rubber composition is provided which comprises (A) 100 parts by weight of at least one diene-based elastomer, (B) about 25 to about 100, optionally about 35 to about 90, phr of filler composed of silica and carbon black, and (C) a silica coupler selected from 15 (i) 3,3'-tetrathiodipropanol polysulfide mixture or (ii) a combination of about 95 to about 25, alternatively about 90 to about 55, weight percent 3, 3 ' - tetrathiodipropanol polysul f ide mixture rr,nt~;n~ng 1 to 8 atoms in the polysulfide bridge and, 20 correspondingly, about 5 to about 75, alternatively about 10 to about 45, weight percent of bis- (3-trialkoxysilylalkyl) polysulfide rr,nt~;n;nr, from 2 to 8 sulfur atoms in the polysulfide bridge such as, for example, at least one of bis- (3-25 triethoxysilylpropyl) tetrasulfide and bis- (3-triethoxysilylpropyl) trisulfide; 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 i~ desired that the weight ratio of 30 said silica coupler to silica is in a range of about o . 01/1 to about 0 .2/1.
In one aspect of the invention, such a rubber composition is provided which is comprised of (A) 100 parts by weight of at least one diene-based elastomer, 35 (B) about 25 to about 90 phr particulate silica, (C) up to about 30 phr carbon black, and (D) a silica coupler which is collectively composed of about ~ 0 to about 55 weight percent 3, 3 ' - tetrathiodipropanol, about 10 to about 45 weight percent of at least one of bis - (3 - triethoxysilylpropyl ) tetra8ulf ide and bis - (3 -5 triethoxysilylpropyl) trisulfide wherein the weightratio o~ silica to carbon black i8 in a range of about 3/1 to about 30/1; wherein the silica is characterized by having a BET surface area in a range of about 50 to about 3 0 0 square meters per gram and a 10 dibutylrh~h~l ~t~o (DBP) absorption value in a range of about 150 to about 300.
Typically, it is desired that the weight ratio of said silica coupler to silica is in a range of about 0 . 01/1 to about 0 . 2/1.
Thus, in one aspect of the invention, the rubber composition contains a combination of both silica and carbon black as elastomer reinforcing pigments.
The rubber composition may contain a minor amount of silica in its silica/carbon black or it may be quantitatively reinforced with silica where carbon black is present in a minor amount.
In another aspect of the invention, a tire is provided having a tread comprised of the said rubber composition of this invention.
The 3,3'-tetratlliodipropanol polysulfide mixture may more fully be described as a highly polar difunctional alcohol that can strongly associate to the silica and further react with a diene polymer through its polysulf ide bridge which contains 1 to 8 sulfur atoms.
The 3, 3 ' - tetrathiodipropanol polysul f ide is ref erred to herein as a mixture because all of the possible sulfide bridges with 1 to 3 sulfur atoms are present .
It i8 believed that the 3,3'-tetrathiodipropanol polysulfide mixture, with its alcohol ~ 21 80887 moiety/associated with the surface of the silica, acts to pull the silica f iller closer to the diene rubber and, thus, give much better dispersion of the silica into the rubber compound, apparently by somewhat 5 inhibiting, or retarding, the tendency of the silica particles to agglomerate together. ~his is considered herein to be beneficial because the better the silica dispersion within the rubber (eg: less silica agglomeration) is exl?ected to provide better physical 10 properties to the rul~ber.
In practice, preferably the 3, 3 ' -tetrathiodipropanol polysulfide mlxture i9 reacted, or caused to be associa~ed, with the silica in situ by mixing it and the silica together with the rubber 15 composition instead of pre - reacting them bef ore adding to the rubber composition.
W~ere it is desired that the rubber composition is primarily reinforced with silica as the reinforcing pigment, it is preferable that the weight ratio of 20 silica to carbon black i8 at least 3/1, preferably at least 10/1 and, thus, for example, in a range of about 3/1 to about 30/1.
In one aspect of the inve~tion, the silica coupler consists essentially of the 3, 3 ' -25 tetrathiodipropanol polysulfide mixture.
In a further aspect, the silica coupler can becomposed of a combination of the 3, 3 ' -tetrathiodipropanol polysulfide mixture together with bi s - ( 3 ~ triethoxys ily] propyl ) tetrasul f ide and/or a 30 blend of 8uch tetrasulfide and bis- (3-triethoxysilylpropyl ) trisulf ide .
The 3, 3 ' - tetrathiodipropanol can also be ref erred to as an a8sociative alcohol coupler. In one aspect, it can also be referred to as a non-gilane silica-to-35 rubber coupler. In particular, it can becharacterized by having the properties of being a ~ 2 1 80887 highly viscous li~uid with an infrared spectrometric absorption bond of medium intensity in a range of about 3570cm-1 to about 345C~m-1 for the alcohol functional group.
~ield desorption and gas chromatographic mass spectrometry analysis indicated that the 3 -3 ' -tetrathiodipropanol polysulf ide has 1 to 8 sulfur atoms in the polysulfide bridge.
The 3, 3 ' - tetrathiodipropanol polysulf idic mixture is considered herein to be particularly advantageous for the practice of this invention because it ha3 a very strong associative attraction to silica and high reactivity for diene rubber which is considered to be a benefit to the exceptionally good dispersion of silica into the rubber Historically, the more homogeneous the dispersion of rubber compound components into the rubber, the better the resultant cured properties of that rubber The 3, 3 ' - tetrathiodipropanol ' s strong association to silica and high affinity, c~mr~t;h;lityl and reactivity with rubber is considered herein to lead to excellent silica dispersion.
In one aspect, such a rubber composition can be provided as being sulfur cured. The sulfur curing i8 accomplished in a col1ventional manner, namely, by curing under conditions of elevated temperature and pressure for a suital~le period of time.
In the practice of this invention, as hereinbefore pointed out, the rubber composition is comprised of at least one diene-based elastomer, or rubber. Thus, it is considered that the elastomer is a sulfur curable elastomer. Such elastomer, or rubber, may be selected, for example, from at least one of cis 1, 4-polyisoprene rubber (natural and/or synthetic, and preferably natural rubber), 3,4-polyisoprene rubber, styrene/butadiene copolymer : ~ 2t80887 rubbers, styrene/isoprene/hllt~; onP terpolymer rubbers, and Ci9 1, 4 -polybutadiene rubber.
In one aspect the rubber is preferably of at least two diene bas~d rubbers. Such diene based 5 rubbers may, for example, be of homopolymers and copolymers of conjugated diene hydroQrbons and copolymers of at least one diene hydrocarbon with a vinyl aromatic compound. Such diene hydrocarbons may be, for example, selected from 1,3-bl~t~ n~ and 10 isoprene. Such vinyl aromatic compound may be, for example, styrene or ~lrh~ml~thylstyrene. For example, a combination of two or more rubber8 is preferred such as at least elastomers selected from cis 1,4-polyisoprene rubber (natural or synthetic, although 15 natural i9 preferred), 3 , 4-polyisoprene rubber, isoprene/butadiene rubber, styrene/isoprene/butadiene rubber, emulsion and solution polymerization derived styrene/butadiene rubbers, cis 1, 4-polybutadiene rubber, medium vinyl polybutadiene rubber having a 20 vinyl content of from 30 to 50, high vinyl polybutadiene having a vinyl content of f rom 5 0 to 75, and emulsion polymerization prepared butadiene/acrylonitrile copolymers.
In one aspect of this invention, an emulsion 25 polymerization derived styrene/butadiene (E-SBR) might be used having a relatively conventional styrene content of about 20 to about 28 percent bound styrene or, for some applications, an E-SBR having a medium to relatively high bound styrene content, namely, a bound 30 styrene content of about 30 to about 45 percent.
The relatively high styrene content of about 30 to about 45 for the E-SBR can be considered beneficial fo~ a purpose of t~nh~n;ng traction, or skid re8istance, of the tire tread. The presence of the E-35 S3R itself is considered beneficial for a purpose off~nh;~nt-l ng proc~ h; 1 ity of the uncured elastomer -2~80887 g composition mixture, especially in comparison to a utilization of a solution polymerization prepared SBR
(S-SBR) .
By emulsion polymerization prepared E-SBR, it is meant that styrene and 1,3-butadiene are copolymerized as an aqueous emulsion. Such are well known to those 8killed in such art. The bound 8tyrene content can vary, for example, from about 5 to 50~. In one aspect, the E-SBR may also contain acrylonitrile to form a terpolymer rubber, as E-SBAR, in amounts, for example, of about 2 to about 30 weight percent bound acrylonitrile in the terpolymer.
Emulsion polymerization prepared styrene/butadiene/acrylonitrile copolymer rubbers crnt~;n;ng about 2 to about 40 weight percent bound acrylonitrile in the copolymer are also contemplated as diene based rubbers for use in thi8 invention.
The solution polymerization prepared SBR (S-SBR) typically has a bound styrene content in a range of about 5 to about 50, preferably about 9 to about 36, percent. The S-SBR can be conveniently prepared, for example, by organo lithium catalyzation in the presence of an organic hydrocarbon solvent.
A purpose of u8ing S-SBR i8 for improved tire rolling resistance as a result of lower hysteresis when it is used in a tire tread composition.
The 3, 4-polyisoprene rubber (3, 4-PI) is considered beneficial for a purpose of ~nh~nr;n~ the tire ' s traction when it is used in a tire tread composition.
The 3, 4-PI and use thereof is more fully described in U.S. Patent No. 5,087,66S which is incorporated herein by reference. The Tg refers to the glass transition temperature which can conveniently be det~rTn;n~rl by a differential scanning calorimeter at a heating rate of 10C per minute.
2I sass7 The cis 1, 4-pol~butadiene rubber (BR) is considered to be beneficial for a purpose of enhancing the tire tread' 8 wear, or treadwear.
Such BR can be prepared, for example, by organic 5 solution polymerization of 1, 3 -butadiene .
The BR may be c4nveniently characterized, for example, by having at least a 909~ cis 1,4-content.
The cis 1,4-polyisoprene and Ci8 1,4-polyisoprene natural rubber are well known to those having skill in 10 the rubber art.
The vulcanized ~ubber composition should contain a sufficient amount of silica, and carbon black reinf orcing f iller ( s ) to contribute a reasonably high modulus and high resistance to tear. The combined 15 weight of the silica and carbon black, as hereinbefore referenced, may be as low as about 30 parts per 100 parts rubber, but is preferably from about 35 or 45 to about 9 0 parts by weight .
The commonly employed siliceous pigments used in 20 rubber compounding applications can be used as the silica in this invention, including pyrogenic and precipitated siliceous pigments ~silica), although precipitate silicas are preferred.
The siliceous pigments preferably employed in 25 this invention are precipitated silicas such as, for example, those obtained by the acidification of a soluble silicate, e.g., sodium silicate.
Such silicas might be characterized, for example, by having a BET surface area, as measured using 30 nitrogen gas, preferably in the range of about 40 to about 600, and more usually in a range of about 50 to about 300 square meters per gram. The BET method of measuring surface area is described in the Jol~rn~l of the Amerir~n ~'hPm~ ~l SQciety, Volume 60, page 304 (1930).
~ ~l 80887 The silica may also be typically characterized by having a dibutylphthalate (DBP) absorption value in a range of about 100 to about 400, and more usually about 150 to about 300.
The silica might be expected to have an average ultimate particle size, for example, in the range of O . 01 to 0 . 05 micron as detPrm1 nPd by the electron microscope, although the silica particles may be even smaller, or possibly larger, in size.
llarious commercially available silicas may be considered for use in this invention such as, only for example herein, and ~ithout limitation, silicas commercially available from PPG Industries under the E~i-Sil trademark Wit~l designations 210, 243, etc;
silicas available from Rhone-Poulenc, with, ~or example, Zeosil 1165~1P and silicas available from Degussa AG with, for example, designations VN2 and VN3, etc.
It is readily understood by those having skill in the art that the rubber composition would be compounded by methods generally known in the ru~ber compounding art, such as mixing the various sulfur-vulri~n; 7~hl e constituent rubbers with various commonly used additive materials 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, anti~ nt~ and antiozonants, peptizing agents and reinforcing materials such as, for example, carbon black. As known to those skilled in the art, ~Pr~n~1~ng on the intended use of the sulfur vul(~;-n; 7i~hl e and sulfur vulcanized material (rubbers), the additives mentioned above are selected and 35 commonly used in conv~n~ n~l amounts.
2i 80887 ~ 12 -Typical amounts of reinforcing type carbon blacks (s), for this invention, if used, are hereinbefore set forth. It is to be appreciated that the silica coupler may be used in conjunction with a carbon black, namely, pre-mixed with a carbon black prior to addition to the rubber composition, and such carbon black i9 to be included in the af oresaid amount of carbon black for the rubber composition formulation. Typical amounts of tackifier reslns, if used, comprise about 0 . 5 to about 10 phr, usually about 1 to about 5 pllr. Typical amounts of processing aids comprise about 1 to about 50 phr. Such processing aids can include, for example, aromatic, napthenic, and/or paraffinic processing oils. Typical amounts of antioxida~1ts comprise about 1 to about 5 phr. Representative antifn~1A~nt~ may be, for example, diphenyl-p-phenylPnPt9~m;nf~ and others, such as, for example, those disclosed in the Vanderl~ilt l?llhher Handbook (1978), pages 344-346. Typical amounts of antiozonants comprise about 1 to 5 phr. Typical amounts of fatty acids, if used, which can include stearic acid comprise about 0 . 5 to about 3 phr.
Typical amounts of zinc oxide comprise about 2 to about 5 phr. Typical amounts of waxes comprise about z5 1 to about 5 phr. Often microcrystalline waxes are used. Typical amounts of peptizers comprise about 0.1 to about 1 phr. Typical peptizers may be, for example, pentachlorothiophenol and dibpn7~m1~nfl~rhpn disulf ide .
The wlc;~n' z~t; ~n is conducted in the presence of a sulfur wlcanizing agent. Examples of suitable sulfur wlcanizing agents include elemental sulfur (free sulfur) or sulfur donating vul-;~n~n~ agents, for example, an aminP disulfide, polymeric polysulfide or sulfur olefin adducts. Preferably, the sulfur vulcanizing agent is Pl Pm~nt~l sulfur. As known to those skilled in the art, sulfur wlcanizing agent8 are used in an amount ranging f rom about 0 . 5 to about 4 phr, or even, in some circumstances, up to about 8 phr, with a range of from about 1 5 to about 2.5, 5 sometimes f rom 2 to 2 . 5, being pref erred .
Accelerators are used to control the time and/or temperature required for wlcanization and to improve the properties of the wlcanizate. In one embodiment, a single ac~Pl~r~t~r syqtem may be used, i.e., primary 10 accelerator. ConvPnt;~n~lly and preferably, a primary accelerator(s) is used in total amounts ranging from about 0 . 5 to about 4, pref erably about 0 . 8 to about 1. 5, phr. In another embodiment, combinations of a primary and a secondary accelerator might be used with 15 the secondary accelerator being used in smaller amounts (of about 0 . 05 to about 3 phr1 in order to activate and to improve the properties of the wlcanizate. Combinations of these accele~ators might be expected to produce a synergistic effect on the 20 final properties and are somewhat better than ~hose produced by use of either accelerator alone In addition, delayed action accelerators may be used which are not affected by normal processing temperatures but produce a satisfactory cure at 25 ordinary wlcanization temperatures. Vulcanization retarders might also be used. Suitable types of accelerators that ma~ be used in the present invention are amines, disulfides, gll~nlfl;nP,q, thioureas, th;~7Ol Pq, th;llr~Tnq, sulfpn~m;~lpql dithiocarbamates 30 and xanthates. Preferably, the primary accelerator ls a sulfenamide. If a second accelerator is used, the secondary accelerator is preferably a gll~nl~l;nP, dithiocarbamate or thiuram compound. The presence and relative amounts of sulfur wlcanizing agent and 35 accelerator(s) are not considered to be an aspect of this invention which is more primarily directed to the use of silica as a reinforcing filler in combination with 3,3'-tetrathiodipropanol polysulfide mixture as a coupling agent for the reinforcing filler.
The presence an~ relative amounts of the above additives are not considered to be an aspect of the present invention which is more primarily directed to the utilization of specif ied blends of rubbers in rubber compositions, in combination with silica and with 3,3'-tetrathiodipropanol polysulfide mixture individually or in combination with bis- (3-triethoxysilylpropyl)tetrasulfide (a polysulfide mixture) as well as, optionally, carbon black, for the reinf orcement of the rubber .
The mixing of the rubber composition can be accomplished by methods known to those having skill in the rubber mixing art. For example, the ingredients are typically mixed in at least two stages, namely, at least one non-productive stage followed by a productive mix stage The final curatives are typically mixed in t~le final stage which is conventionally called the "productive" mix stage in which the mixing typically occurs at a temperature, or ultimate temperature, lower than the mix temperature (s) than the preceding non-productive mix stage (s) . The rubber, silica and silica coupler, and carbon black if used, are mixed in one or more non-productive mix stages. The terms "non-productive" and ~productive~' mix stases are well known to those having skill in the rubber mixing art.
The rubber composition of this invention can be used for various purposes. For example, it can be used for various tire compounds. Such tires can be built, shaped, molded and cured by various methods which are known and will be readily apparent to those having skill in such art.
2t 80887 The invention may be better understood by reference to the following examples in which the parts and percentages are by weight unless otherwise indicated .
EXAMP~ I
In this Example, 3,3'-tetrathiodipropanol polysulfide mlxture on a carbon black carrier was evaluated as an alternative for a relatively commonly used silica coupling agent, namely, bis- (3-triethoxysilylpropyl~tetrasulfide polysulfide mixture, on a carbon black as a carrier, in a silica reinforced rubber composition.
The rubber compositions ~ nt~n;ng the materials set out in Table 1 were prepared in a BR Banbury rubber mixer using three separate, seouential stages of addition (mixing) ~ namely, two non-productive mix stages and one final productive mix to temperatures of 160C, 160C and 120C and times of 4 minutes, 4 minutes and 2 minutes, respectively. The amount of coupler is listed as being "variable" in Table 1 and is more specifically set forth in Table 2.
It is clearly evident that utilization of the coupling agent appears to be necessary to obtain suitable cured propertieg in a silica cn~t~;n1ng rubber composition, or compound. Such properties include tensile strength at break, the 100 and 300g6 modulus values, rebound hardness, Rheovibron E ' and particularly DIN abrasion resistance (lower indicate less, or values better, abrasion values). Samples 2 and 3, when compared to Sample 1, which was prepare~
in the absence of ut;1;7~t;on of the silica coupling agent, clearly show the advantage of the coupling agents. The properties of Sample 3, which cnnt~;
the silica coupler utilized in this invention has properties comparable to those exhibited by Sample 2 which t-l~nt~;n~ the conv~nt;--n~l silane coupling agent In particular, this Example shows that the 3, 3 ' -tetrathiodipropanol polysulfide mixture, as utilized 5 in Sample 3, can provide significant ilL.~ ts in modulus, rebound, hardness and abrasion when compared to control Sample 1 which does not contain coupling agent. Furth~ - ~, these properties compare favorably to those of Sample 2 which ,..nt~;nfl the 10 conv~nt;l~n~l silane coupling agent.
Table 1 ls~ Nori-ProducsiYe Natural Rubber1 100 . 00 15Carbon Black 35 . 00 Processing Oil 5 oo Zinc Oxide 5 . 00 Fatty Acid 2 . 00 Antioxidant2 2 . 00 2nd llTon-Pro~c~iY~
Silica3 15 . 00 Bis - ( 3 - triethoxysilylpropyl ) variable tetrasul f ide4 3, 3 ' - tetrathiodipropanol variable 25polysulfide mixture Pro~ tive Sulfur ¦ l . 40 Accelerator, sulfenamide type ¦ l . 00 30 l) Synthetic cis 1,4-polyisoprene rubber (NAT
2200) from The Goodyear Tire ~ Rubber Company;
- 17- 21808~7 2) of the polymerized 1,2-dihydro-2,2,4-trimethylquinol ine type i 3) silica obtained as Hi-Sil-210 from PPG
Industries , Inc .;
4) 50% active composite composed of the organosilane tetrasulfide on or with carbon black in a 50/50 weight ratio available as material X50S from Degussa Gmb~.
Technically the organosilane polysulfide is understood to be a composite, or mixture, in which the average polysulfide bridge contains about 3 . 5 to 4 connecting sulfur atoms, although the mixture may contain such polysulfides wi~h about 2 to 8 rt.nnF~ ; ng sulfur atoms.
5) 3,3'-tetrathiodipropanol polysulfide c~nt~1ning 1 to 8 sulfur atoms in the polysulfide bridge obtained as a highly viscous liquid from the reaction of 3-chluLu~Lu~anol (two molar equivalents) with 1 molar equivalent of aqueous sodium tetrasulf ide . It is supported 1 to 1 by weight on N330 carbon black for all examples used in this specif ication .
Table 2 Sa~ le # 1 2 X50S (Degussa GmbH) 0 3 0 3, 3 ' - tetrathiodipropanol 0 0 2 Rheomet- r (1~0C
Max. Torque, dNm 30.2 34.3 33.0 Min. Torque, dNm 7 . 0 7 . 0 7 . 0 Del ta Torque 2 3 . 2 2 7 . 3 2 6 . 0 T9~, minutes 23.0 18.7 17.0 Strç~q -str~"
Tensile Strength, MPa 17 . 6 19 . 7 18 . 8 Elongation at Break, ~ 630 621 626 10096 Modulus, MPa 1.2 1.7 1.5 300~ Modulus, MPa 5.5 8.0 6.8 Re~ou~d 100C, ~ 1 55.1 1 59.8 1 58.6 ~ar~n~q~q Shore A, 100C ¦ 46.4 ¦ 51.9 ¦ 51.2 Rheo ~i hron 20 33' at 60C, MPa 10.6 11.5 10.4 Tan Delta at 60~ .105 . 092 . 097 DIN Abrasion 231 156 186 ~XAMPT ,li I I
In this ~xample, 3, 3 ' - tetrathiodipropanol polysulfide mixture on a carbon black carrier was evaluated as a silica coupling agent in a silica reinforced rubber composition.
The rubber c~mpositions ~ nti~n~ng the materials set out in Table 3 were prepared ih a BR Banbury rubber mixer using three separate, sequential stages of addition (mixing), namely, two non-productive mix 2 1 ~0887 stages and one final productive mix to temperatures of 160C, 160C and 120C and times of 4 minutes, 4 minutes and 2 minutes, respectively. The amount of coupler i8 listed in Table 3 and is more specif ically 5 set forth in Table 4.
It is clearly evident that utilization of the coupling agent appears to be necegsary to obtain suitable cured properties in a silica containing rubber composition, or compound. Such properties include tensile strength at break, the 100 and 30076 modulus values, rebound hardness, Rheovibron E ' and particularly DIN abrasion resistance (lower indicate less, or values better, abrasion values). Sample 5 of Table 4, when compared to Sample 4 of Table 4, which 15 was prepared in the absence of utilization of the silica coupling agent, clearly show the advantage of the coupling agent . This Bxample shows that the 3, 3 ' -tetrathiodipropanol polysulfide mixture, as utilized in Sample 5, can provide il~l~LUV~ ts in modulus, 20 rebound, hardnes~ and abrasion when compared to control Sample 4 which does not contain coupling agent .
: ~ 2t80887 Table 3 ls~ Nnn-Prod~c ive Natural Rubberl 100 . 00 Silica2 20 . 00 5Carbon Black 15 . 00 Processing Oil 5 . 00 Zinc Oxide 5 . 00 Fatty Acid 2 . 00 Antioxidant3 2 . 00 3,3'-tetrathiodipro~anol 0 or 3.00 polysulfide mixture 2nd Nnn-Pxo~ ct iYe Silica2 ¦ 15 . 00 Produc~ i Ye Sulfur 2 . 00 Accelerators, sulfellamide type 2.50 Diphenyl g~l~n;d;nP 1.00 1 ) Synthetic Ci9 1, 4 -polyisoprene rubber (NAT
2200~ from The Goodyear Tire & Rubber Company;
2) silica obtained as ~i-Sil-210 from PPG
Industries, Inc.;
3) of the polymerized 1,2-dihydro-2,2,4-trimethylquinoline type;
4) 3,3'-tetrathiodipropanol polysulfide cnnt~;n;ng 1 to 8 sulfur atom.s in the polysulfide bridge obtained as a highly viscous liquid from the reaction of 3-chloropropanol (two molar equivalents) with 1 molar equivalent of aqueous sodium tetrasulfide. It is supported 1 to 1 by .
2~80887 weight on N330 carbon black ~or all examples used in this specification.
Table 4 5 Sam~l e # 4 3, 3 ' - tetrathiodipropanol 0 3 mixture Rheometer (150C) Max. Torque, dNm 50.1 48.5 10Min. Torque, dNm 8 . 3 5 . 0 Delta Torque 41.8 43.5 T9n~ minutes 14.3 10.0 Stress -Str;~ i n Tengile Strength, MPa 18 . 4 19 . 2 15 Elongation at Break, ~ 574 526 10 0 9~ Modulus, MPa 1 . 9 2 . 6 300% Modulus, MPa 6.8 9.9 ~ebound 100 C, ~ 1 64 . 9 1 66 . 8 2 0 Hardness Shore A, 100C ¦ 62.9 ¦ 64.8 Rheovibron B' at 60C, MPa 19.1 20.0 Tan Delta at 60~ . 050 . 054 25DIN Abragion 193 180 BXAMPI,E ITI
In this Example, 3, 3 ' -tetrathiodipropanol 30 polysulfide mixture was evaluated as a coupling ayent in a highly silica loaded rubber composition. Rubber compositions c~n~;n;ng the materials set out in Table 5 were prepared in a BR Banbury mixer using three separate, sequential stages of addition, namely, two non-productive mix stages and one productive mix stage to temperatures o~ 160C, 160C and 120C and times of 4 minute~3, 4 minutes and 2 minutes, respectively. The 5 cure behavior and cured properties are indicated in Table 8.
The use o~ 3, 3 ' - tetrathiodipropanol polysulf ide alone or in combination with the conventional coupling agent gave rubber compositions exhibiting excellent 10 cured properties in the presence o~ high levels of silica filler.
T~lble 5 lst~ Non-Pro,.',-ctiy~
15Styrene/Butadiene R~bberl 68 . 75 Polybutadiene Rubber~ 15 . 00 Natural Rub~:1er 35 . 00 Carbon Black3 20 . 00 Silica4 40 . 00 20Zinc Oxide 3 . 00 Fatty Acid 3 00 Antioxidants 2 . 00 Processing Aid6 5 00 3,3'-tetrathiodipropanol sulfide8 4 00 2 5 2nd Nor - Pro~ t ;' ve Silica4 30 . 00 Bis- (3-triethoxysil~lpropyl) 0 or 3 .00 tetrasulfide7 (50~ active) 3,3~-tetrathiodipropanol poly,3ulfide8 0 or 3.00 3 0 Pro~'uct i Ye Sulfur 1.40 Accelerator, sulfenamide type 1. 80 Diphenyl g~ n~ fl; n~ 1. 50 , _ . . .. ..
`, 2180887 1) Emulsion polymerization prepared styrene/butadiene copolymer elastomer cnnt~;nlng 23.5~ bound styrene and 37.5 phr aromatic oil from The Goodyear Tire & Rubber 5 Company;
2) high ci3 1,4-polybutadiene from The Goodyear Tire ~ Rubber Company;
10 3) carbon black as N330;
4) Zeosil 1165 MP from Rhone-Polllenc;
5 ) polymerized 1, 2 - dihydro - 2, 2, 4 -trimethyl~-;nrl ;nP type;
6) Struktol A6;
Various llydLu~yYIlfides have also been used to reinforce silica in carbon black filled rubber (EP
Patent Publication No. 489,313).
The term "phr" if used herein, and according to conventional practice, refers to "parts of a re8pective material l?er 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. The terms "rubber composition", "compounded rubber" and ~rubber compound", if used herein, are used interchangeably to refer to "rubber which ha8 been blended or mixed with various ingredients and materials" and such terms are well known to those ` ~ 2180887 having skill in the rubber mlxing or rubber compounding art.
A reference to an elastomer~ s Tg refers to its glasg transition temperature, which can converiently 5 be determined by a differential scanning calorimeter at a heating rate of 10C per minute.
SummarY and Practlce of the Tnv~nt;on In accordance with one aspect of this invention, 10 a rubber composition is provided which comprises (A) 100 parts by weight of at least one diene-based elastomer, (B) about 25 to about 100, optionally about 35 to about 90, phr of filler composed of silica and carbon black, and (C) a silica coupler selected from 15 (i) 3,3'-tetrathiodipropanol polysulfide mixture or (ii) a combination of about 95 to about 25, alternatively about 90 to about 55, weight percent 3, 3 ' - tetrathiodipropanol polysul f ide mixture rr,nt~;n~ng 1 to 8 atoms in the polysulfide bridge and, 20 correspondingly, about 5 to about 75, alternatively about 10 to about 45, weight percent of bis- (3-trialkoxysilylalkyl) polysulfide rr,nt~;n;nr, from 2 to 8 sulfur atoms in the polysulfide bridge such as, for example, at least one of bis- (3-25 triethoxysilylpropyl) tetrasulfide and bis- (3-triethoxysilylpropyl) trisulfide; 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 i~ desired that the weight ratio of 30 said silica coupler to silica is in a range of about o . 01/1 to about 0 .2/1.
In one aspect of the invention, such a rubber composition is provided which is comprised of (A) 100 parts by weight of at least one diene-based elastomer, 35 (B) about 25 to about 90 phr particulate silica, (C) up to about 30 phr carbon black, and (D) a silica coupler which is collectively composed of about ~ 0 to about 55 weight percent 3, 3 ' - tetrathiodipropanol, about 10 to about 45 weight percent of at least one of bis - (3 - triethoxysilylpropyl ) tetra8ulf ide and bis - (3 -5 triethoxysilylpropyl) trisulfide wherein the weightratio o~ silica to carbon black i8 in a range of about 3/1 to about 30/1; wherein the silica is characterized by having a BET surface area in a range of about 50 to about 3 0 0 square meters per gram and a 10 dibutylrh~h~l ~t~o (DBP) absorption value in a range of about 150 to about 300.
Typically, it is desired that the weight ratio of said silica coupler to silica is in a range of about 0 . 01/1 to about 0 . 2/1.
Thus, in one aspect of the invention, the rubber composition contains a combination of both silica and carbon black as elastomer reinforcing pigments.
The rubber composition may contain a minor amount of silica in its silica/carbon black or it may be quantitatively reinforced with silica where carbon black is present in a minor amount.
In another aspect of the invention, a tire is provided having a tread comprised of the said rubber composition of this invention.
The 3,3'-tetratlliodipropanol polysulfide mixture may more fully be described as a highly polar difunctional alcohol that can strongly associate to the silica and further react with a diene polymer through its polysulf ide bridge which contains 1 to 8 sulfur atoms.
The 3, 3 ' - tetrathiodipropanol polysul f ide is ref erred to herein as a mixture because all of the possible sulfide bridges with 1 to 3 sulfur atoms are present .
It i8 believed that the 3,3'-tetrathiodipropanol polysulfide mixture, with its alcohol ~ 21 80887 moiety/associated with the surface of the silica, acts to pull the silica f iller closer to the diene rubber and, thus, give much better dispersion of the silica into the rubber compound, apparently by somewhat 5 inhibiting, or retarding, the tendency of the silica particles to agglomerate together. ~his is considered herein to be beneficial because the better the silica dispersion within the rubber (eg: less silica agglomeration) is exl?ected to provide better physical 10 properties to the rul~ber.
In practice, preferably the 3, 3 ' -tetrathiodipropanol polysulfide mlxture i9 reacted, or caused to be associa~ed, with the silica in situ by mixing it and the silica together with the rubber 15 composition instead of pre - reacting them bef ore adding to the rubber composition.
W~ere it is desired that the rubber composition is primarily reinforced with silica as the reinforcing pigment, it is preferable that the weight ratio of 20 silica to carbon black i8 at least 3/1, preferably at least 10/1 and, thus, for example, in a range of about 3/1 to about 30/1.
In one aspect of the inve~tion, the silica coupler consists essentially of the 3, 3 ' -25 tetrathiodipropanol polysulfide mixture.
In a further aspect, the silica coupler can becomposed of a combination of the 3, 3 ' -tetrathiodipropanol polysulfide mixture together with bi s - ( 3 ~ triethoxys ily] propyl ) tetrasul f ide and/or a 30 blend of 8uch tetrasulfide and bis- (3-triethoxysilylpropyl ) trisulf ide .
The 3, 3 ' - tetrathiodipropanol can also be ref erred to as an a8sociative alcohol coupler. In one aspect, it can also be referred to as a non-gilane silica-to-35 rubber coupler. In particular, it can becharacterized by having the properties of being a ~ 2 1 80887 highly viscous li~uid with an infrared spectrometric absorption bond of medium intensity in a range of about 3570cm-1 to about 345C~m-1 for the alcohol functional group.
~ield desorption and gas chromatographic mass spectrometry analysis indicated that the 3 -3 ' -tetrathiodipropanol polysulf ide has 1 to 8 sulfur atoms in the polysulfide bridge.
The 3, 3 ' - tetrathiodipropanol polysulf idic mixture is considered herein to be particularly advantageous for the practice of this invention because it ha3 a very strong associative attraction to silica and high reactivity for diene rubber which is considered to be a benefit to the exceptionally good dispersion of silica into the rubber Historically, the more homogeneous the dispersion of rubber compound components into the rubber, the better the resultant cured properties of that rubber The 3, 3 ' - tetrathiodipropanol ' s strong association to silica and high affinity, c~mr~t;h;lityl and reactivity with rubber is considered herein to lead to excellent silica dispersion.
In one aspect, such a rubber composition can be provided as being sulfur cured. The sulfur curing i8 accomplished in a col1ventional manner, namely, by curing under conditions of elevated temperature and pressure for a suital~le period of time.
In the practice of this invention, as hereinbefore pointed out, the rubber composition is comprised of at least one diene-based elastomer, or rubber. Thus, it is considered that the elastomer is a sulfur curable elastomer. Such elastomer, or rubber, may be selected, for example, from at least one of cis 1, 4-polyisoprene rubber (natural and/or synthetic, and preferably natural rubber), 3,4-polyisoprene rubber, styrene/butadiene copolymer : ~ 2t80887 rubbers, styrene/isoprene/hllt~; onP terpolymer rubbers, and Ci9 1, 4 -polybutadiene rubber.
In one aspect the rubber is preferably of at least two diene bas~d rubbers. Such diene based 5 rubbers may, for example, be of homopolymers and copolymers of conjugated diene hydroQrbons and copolymers of at least one diene hydrocarbon with a vinyl aromatic compound. Such diene hydrocarbons may be, for example, selected from 1,3-bl~t~ n~ and 10 isoprene. Such vinyl aromatic compound may be, for example, styrene or ~lrh~ml~thylstyrene. For example, a combination of two or more rubber8 is preferred such as at least elastomers selected from cis 1,4-polyisoprene rubber (natural or synthetic, although 15 natural i9 preferred), 3 , 4-polyisoprene rubber, isoprene/butadiene rubber, styrene/isoprene/butadiene rubber, emulsion and solution polymerization derived styrene/butadiene rubbers, cis 1, 4-polybutadiene rubber, medium vinyl polybutadiene rubber having a 20 vinyl content of from 30 to 50, high vinyl polybutadiene having a vinyl content of f rom 5 0 to 75, and emulsion polymerization prepared butadiene/acrylonitrile copolymers.
In one aspect of this invention, an emulsion 25 polymerization derived styrene/butadiene (E-SBR) might be used having a relatively conventional styrene content of about 20 to about 28 percent bound styrene or, for some applications, an E-SBR having a medium to relatively high bound styrene content, namely, a bound 30 styrene content of about 30 to about 45 percent.
The relatively high styrene content of about 30 to about 45 for the E-SBR can be considered beneficial fo~ a purpose of t~nh~n;ng traction, or skid re8istance, of the tire tread. The presence of the E-35 S3R itself is considered beneficial for a purpose off~nh;~nt-l ng proc~ h; 1 ity of the uncured elastomer -2~80887 g composition mixture, especially in comparison to a utilization of a solution polymerization prepared SBR
(S-SBR) .
By emulsion polymerization prepared E-SBR, it is meant that styrene and 1,3-butadiene are copolymerized as an aqueous emulsion. Such are well known to those 8killed in such art. The bound 8tyrene content can vary, for example, from about 5 to 50~. In one aspect, the E-SBR may also contain acrylonitrile to form a terpolymer rubber, as E-SBAR, in amounts, for example, of about 2 to about 30 weight percent bound acrylonitrile in the terpolymer.
Emulsion polymerization prepared styrene/butadiene/acrylonitrile copolymer rubbers crnt~;n;ng about 2 to about 40 weight percent bound acrylonitrile in the copolymer are also contemplated as diene based rubbers for use in thi8 invention.
The solution polymerization prepared SBR (S-SBR) typically has a bound styrene content in a range of about 5 to about 50, preferably about 9 to about 36, percent. The S-SBR can be conveniently prepared, for example, by organo lithium catalyzation in the presence of an organic hydrocarbon solvent.
A purpose of u8ing S-SBR i8 for improved tire rolling resistance as a result of lower hysteresis when it is used in a tire tread composition.
The 3, 4-polyisoprene rubber (3, 4-PI) is considered beneficial for a purpose of ~nh~nr;n~ the tire ' s traction when it is used in a tire tread composition.
The 3, 4-PI and use thereof is more fully described in U.S. Patent No. 5,087,66S which is incorporated herein by reference. The Tg refers to the glass transition temperature which can conveniently be det~rTn;n~rl by a differential scanning calorimeter at a heating rate of 10C per minute.
2I sass7 The cis 1, 4-pol~butadiene rubber (BR) is considered to be beneficial for a purpose of enhancing the tire tread' 8 wear, or treadwear.
Such BR can be prepared, for example, by organic 5 solution polymerization of 1, 3 -butadiene .
The BR may be c4nveniently characterized, for example, by having at least a 909~ cis 1,4-content.
The cis 1,4-polyisoprene and Ci8 1,4-polyisoprene natural rubber are well known to those having skill in 10 the rubber art.
The vulcanized ~ubber composition should contain a sufficient amount of silica, and carbon black reinf orcing f iller ( s ) to contribute a reasonably high modulus and high resistance to tear. The combined 15 weight of the silica and carbon black, as hereinbefore referenced, may be as low as about 30 parts per 100 parts rubber, but is preferably from about 35 or 45 to about 9 0 parts by weight .
The commonly employed siliceous pigments used in 20 rubber compounding applications can be used as the silica in this invention, including pyrogenic and precipitated siliceous pigments ~silica), although precipitate silicas are preferred.
The siliceous pigments preferably employed in 25 this invention are precipitated silicas such as, for example, those obtained by the acidification of a soluble silicate, e.g., sodium silicate.
Such silicas might be characterized, for example, by having a BET surface area, as measured using 30 nitrogen gas, preferably in the range of about 40 to about 600, and more usually in a range of about 50 to about 300 square meters per gram. The BET method of measuring surface area is described in the Jol~rn~l of the Amerir~n ~'hPm~ ~l SQciety, Volume 60, page 304 (1930).
~ ~l 80887 The silica may also be typically characterized by having a dibutylphthalate (DBP) absorption value in a range of about 100 to about 400, and more usually about 150 to about 300.
The silica might be expected to have an average ultimate particle size, for example, in the range of O . 01 to 0 . 05 micron as detPrm1 nPd by the electron microscope, although the silica particles may be even smaller, or possibly larger, in size.
llarious commercially available silicas may be considered for use in this invention such as, only for example herein, and ~ithout limitation, silicas commercially available from PPG Industries under the E~i-Sil trademark Wit~l designations 210, 243, etc;
silicas available from Rhone-Poulenc, with, ~or example, Zeosil 1165~1P and silicas available from Degussa AG with, for example, designations VN2 and VN3, etc.
It is readily understood by those having skill in the art that the rubber composition would be compounded by methods generally known in the ru~ber compounding art, such as mixing the various sulfur-vulri~n; 7~hl e constituent rubbers with various commonly used additive materials 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, anti~ nt~ and antiozonants, peptizing agents and reinforcing materials such as, for example, carbon black. As known to those skilled in the art, ~Pr~n~1~ng on the intended use of the sulfur vul(~;-n; 7i~hl e and sulfur vulcanized material (rubbers), the additives mentioned above are selected and 35 commonly used in conv~n~ n~l amounts.
2i 80887 ~ 12 -Typical amounts of reinforcing type carbon blacks (s), for this invention, if used, are hereinbefore set forth. It is to be appreciated that the silica coupler may be used in conjunction with a carbon black, namely, pre-mixed with a carbon black prior to addition to the rubber composition, and such carbon black i9 to be included in the af oresaid amount of carbon black for the rubber composition formulation. Typical amounts of tackifier reslns, if used, comprise about 0 . 5 to about 10 phr, usually about 1 to about 5 pllr. Typical amounts of processing aids comprise about 1 to about 50 phr. Such processing aids can include, for example, aromatic, napthenic, and/or paraffinic processing oils. Typical amounts of antioxida~1ts comprise about 1 to about 5 phr. Representative antifn~1A~nt~ may be, for example, diphenyl-p-phenylPnPt9~m;nf~ and others, such as, for example, those disclosed in the Vanderl~ilt l?llhher Handbook (1978), pages 344-346. Typical amounts of antiozonants comprise about 1 to 5 phr. Typical amounts of fatty acids, if used, which can include stearic acid comprise about 0 . 5 to about 3 phr.
Typical amounts of zinc oxide comprise about 2 to about 5 phr. Typical amounts of waxes comprise about z5 1 to about 5 phr. Often microcrystalline waxes are used. Typical amounts of peptizers comprise about 0.1 to about 1 phr. Typical peptizers may be, for example, pentachlorothiophenol and dibpn7~m1~nfl~rhpn disulf ide .
The wlc;~n' z~t; ~n is conducted in the presence of a sulfur wlcanizing agent. Examples of suitable sulfur wlcanizing agents include elemental sulfur (free sulfur) or sulfur donating vul-;~n~n~ agents, for example, an aminP disulfide, polymeric polysulfide or sulfur olefin adducts. Preferably, the sulfur vulcanizing agent is Pl Pm~nt~l sulfur. As known to those skilled in the art, sulfur wlcanizing agent8 are used in an amount ranging f rom about 0 . 5 to about 4 phr, or even, in some circumstances, up to about 8 phr, with a range of from about 1 5 to about 2.5, 5 sometimes f rom 2 to 2 . 5, being pref erred .
Accelerators are used to control the time and/or temperature required for wlcanization and to improve the properties of the wlcanizate. In one embodiment, a single ac~Pl~r~t~r syqtem may be used, i.e., primary 10 accelerator. ConvPnt;~n~lly and preferably, a primary accelerator(s) is used in total amounts ranging from about 0 . 5 to about 4, pref erably about 0 . 8 to about 1. 5, phr. In another embodiment, combinations of a primary and a secondary accelerator might be used with 15 the secondary accelerator being used in smaller amounts (of about 0 . 05 to about 3 phr1 in order to activate and to improve the properties of the wlcanizate. Combinations of these accele~ators might be expected to produce a synergistic effect on the 20 final properties and are somewhat better than ~hose produced by use of either accelerator alone In addition, delayed action accelerators may be used which are not affected by normal processing temperatures but produce a satisfactory cure at 25 ordinary wlcanization temperatures. Vulcanization retarders might also be used. Suitable types of accelerators that ma~ be used in the present invention are amines, disulfides, gll~nlfl;nP,q, thioureas, th;~7Ol Pq, th;llr~Tnq, sulfpn~m;~lpql dithiocarbamates 30 and xanthates. Preferably, the primary accelerator ls a sulfenamide. If a second accelerator is used, the secondary accelerator is preferably a gll~nl~l;nP, dithiocarbamate or thiuram compound. The presence and relative amounts of sulfur wlcanizing agent and 35 accelerator(s) are not considered to be an aspect of this invention which is more primarily directed to the use of silica as a reinforcing filler in combination with 3,3'-tetrathiodipropanol polysulfide mixture as a coupling agent for the reinforcing filler.
The presence an~ relative amounts of the above additives are not considered to be an aspect of the present invention which is more primarily directed to the utilization of specif ied blends of rubbers in rubber compositions, in combination with silica and with 3,3'-tetrathiodipropanol polysulfide mixture individually or in combination with bis- (3-triethoxysilylpropyl)tetrasulfide (a polysulfide mixture) as well as, optionally, carbon black, for the reinf orcement of the rubber .
The mixing of the rubber composition can be accomplished by methods known to those having skill in the rubber mixing art. For example, the ingredients are typically mixed in at least two stages, namely, at least one non-productive stage followed by a productive mix stage The final curatives are typically mixed in t~le final stage which is conventionally called the "productive" mix stage in which the mixing typically occurs at a temperature, or ultimate temperature, lower than the mix temperature (s) than the preceding non-productive mix stage (s) . The rubber, silica and silica coupler, and carbon black if used, are mixed in one or more non-productive mix stages. The terms "non-productive" and ~productive~' mix stases are well known to those having skill in the rubber mixing art.
The rubber composition of this invention can be used for various purposes. For example, it can be used for various tire compounds. Such tires can be built, shaped, molded and cured by various methods which are known and will be readily apparent to those having skill in such art.
2t 80887 The invention may be better understood by reference to the following examples in which the parts and percentages are by weight unless otherwise indicated .
EXAMP~ I
In this Example, 3,3'-tetrathiodipropanol polysulfide mlxture on a carbon black carrier was evaluated as an alternative for a relatively commonly used silica coupling agent, namely, bis- (3-triethoxysilylpropyl~tetrasulfide polysulfide mixture, on a carbon black as a carrier, in a silica reinforced rubber composition.
The rubber compositions ~ nt~n;ng the materials set out in Table 1 were prepared in a BR Banbury rubber mixer using three separate, seouential stages of addition (mixing) ~ namely, two non-productive mix stages and one final productive mix to temperatures of 160C, 160C and 120C and times of 4 minutes, 4 minutes and 2 minutes, respectively. The amount of coupler is listed as being "variable" in Table 1 and is more specifically set forth in Table 2.
It is clearly evident that utilization of the coupling agent appears to be necessary to obtain suitable cured propertieg in a silica cn~t~;n1ng rubber composition, or compound. Such properties include tensile strength at break, the 100 and 300g6 modulus values, rebound hardness, Rheovibron E ' and particularly DIN abrasion resistance (lower indicate less, or values better, abrasion values). Samples 2 and 3, when compared to Sample 1, which was prepare~
in the absence of ut;1;7~t;on of the silica coupling agent, clearly show the advantage of the coupling agents. The properties of Sample 3, which cnnt~;
the silica coupler utilized in this invention has properties comparable to those exhibited by Sample 2 which t-l~nt~;n~ the conv~nt;--n~l silane coupling agent In particular, this Example shows that the 3, 3 ' -tetrathiodipropanol polysulfide mixture, as utilized 5 in Sample 3, can provide significant ilL.~ ts in modulus, rebound, hardness and abrasion when compared to control Sample 1 which does not contain coupling agent. Furth~ - ~, these properties compare favorably to those of Sample 2 which ,..nt~;nfl the 10 conv~nt;l~n~l silane coupling agent.
Table 1 ls~ Nori-ProducsiYe Natural Rubber1 100 . 00 15Carbon Black 35 . 00 Processing Oil 5 oo Zinc Oxide 5 . 00 Fatty Acid 2 . 00 Antioxidant2 2 . 00 2nd llTon-Pro~c~iY~
Silica3 15 . 00 Bis - ( 3 - triethoxysilylpropyl ) variable tetrasul f ide4 3, 3 ' - tetrathiodipropanol variable 25polysulfide mixture Pro~ tive Sulfur ¦ l . 40 Accelerator, sulfenamide type ¦ l . 00 30 l) Synthetic cis 1,4-polyisoprene rubber (NAT
2200) from The Goodyear Tire ~ Rubber Company;
- 17- 21808~7 2) of the polymerized 1,2-dihydro-2,2,4-trimethylquinol ine type i 3) silica obtained as Hi-Sil-210 from PPG
Industries , Inc .;
4) 50% active composite composed of the organosilane tetrasulfide on or with carbon black in a 50/50 weight ratio available as material X50S from Degussa Gmb~.
Technically the organosilane polysulfide is understood to be a composite, or mixture, in which the average polysulfide bridge contains about 3 . 5 to 4 connecting sulfur atoms, although the mixture may contain such polysulfides wi~h about 2 to 8 rt.nnF~ ; ng sulfur atoms.
5) 3,3'-tetrathiodipropanol polysulfide c~nt~1ning 1 to 8 sulfur atoms in the polysulfide bridge obtained as a highly viscous liquid from the reaction of 3-chluLu~Lu~anol (two molar equivalents) with 1 molar equivalent of aqueous sodium tetrasulf ide . It is supported 1 to 1 by weight on N330 carbon black for all examples used in this specif ication .
Table 2 Sa~ le # 1 2 X50S (Degussa GmbH) 0 3 0 3, 3 ' - tetrathiodipropanol 0 0 2 Rheomet- r (1~0C
Max. Torque, dNm 30.2 34.3 33.0 Min. Torque, dNm 7 . 0 7 . 0 7 . 0 Del ta Torque 2 3 . 2 2 7 . 3 2 6 . 0 T9~, minutes 23.0 18.7 17.0 Strç~q -str~"
Tensile Strength, MPa 17 . 6 19 . 7 18 . 8 Elongation at Break, ~ 630 621 626 10096 Modulus, MPa 1.2 1.7 1.5 300~ Modulus, MPa 5.5 8.0 6.8 Re~ou~d 100C, ~ 1 55.1 1 59.8 1 58.6 ~ar~n~q~q Shore A, 100C ¦ 46.4 ¦ 51.9 ¦ 51.2 Rheo ~i hron 20 33' at 60C, MPa 10.6 11.5 10.4 Tan Delta at 60~ .105 . 092 . 097 DIN Abrasion 231 156 186 ~XAMPT ,li I I
In this ~xample, 3, 3 ' - tetrathiodipropanol polysulfide mixture on a carbon black carrier was evaluated as a silica coupling agent in a silica reinforced rubber composition.
The rubber c~mpositions ~ nti~n~ng the materials set out in Table 3 were prepared ih a BR Banbury rubber mixer using three separate, sequential stages of addition (mixing), namely, two non-productive mix 2 1 ~0887 stages and one final productive mix to temperatures of 160C, 160C and 120C and times of 4 minutes, 4 minutes and 2 minutes, respectively. The amount of coupler i8 listed in Table 3 and is more specif ically 5 set forth in Table 4.
It is clearly evident that utilization of the coupling agent appears to be necegsary to obtain suitable cured properties in a silica containing rubber composition, or compound. Such properties include tensile strength at break, the 100 and 30076 modulus values, rebound hardness, Rheovibron E ' and particularly DIN abrasion resistance (lower indicate less, or values better, abrasion values). Sample 5 of Table 4, when compared to Sample 4 of Table 4, which 15 was prepared in the absence of utilization of the silica coupling agent, clearly show the advantage of the coupling agent . This Bxample shows that the 3, 3 ' -tetrathiodipropanol polysulfide mixture, as utilized in Sample 5, can provide il~l~LUV~ ts in modulus, 20 rebound, hardnes~ and abrasion when compared to control Sample 4 which does not contain coupling agent .
: ~ 2t80887 Table 3 ls~ Nnn-Prod~c ive Natural Rubberl 100 . 00 Silica2 20 . 00 5Carbon Black 15 . 00 Processing Oil 5 . 00 Zinc Oxide 5 . 00 Fatty Acid 2 . 00 Antioxidant3 2 . 00 3,3'-tetrathiodipro~anol 0 or 3.00 polysulfide mixture 2nd Nnn-Pxo~ ct iYe Silica2 ¦ 15 . 00 Produc~ i Ye Sulfur 2 . 00 Accelerators, sulfellamide type 2.50 Diphenyl g~l~n;d;nP 1.00 1 ) Synthetic Ci9 1, 4 -polyisoprene rubber (NAT
2200~ from The Goodyear Tire & Rubber Company;
2) silica obtained as ~i-Sil-210 from PPG
Industries, Inc.;
3) of the polymerized 1,2-dihydro-2,2,4-trimethylquinoline type;
4) 3,3'-tetrathiodipropanol polysulfide cnnt~;n;ng 1 to 8 sulfur atom.s in the polysulfide bridge obtained as a highly viscous liquid from the reaction of 3-chloropropanol (two molar equivalents) with 1 molar equivalent of aqueous sodium tetrasulfide. It is supported 1 to 1 by .
2~80887 weight on N330 carbon black ~or all examples used in this specification.
Table 4 5 Sam~l e # 4 3, 3 ' - tetrathiodipropanol 0 3 mixture Rheometer (150C) Max. Torque, dNm 50.1 48.5 10Min. Torque, dNm 8 . 3 5 . 0 Delta Torque 41.8 43.5 T9n~ minutes 14.3 10.0 Stress -Str;~ i n Tengile Strength, MPa 18 . 4 19 . 2 15 Elongation at Break, ~ 574 526 10 0 9~ Modulus, MPa 1 . 9 2 . 6 300% Modulus, MPa 6.8 9.9 ~ebound 100 C, ~ 1 64 . 9 1 66 . 8 2 0 Hardness Shore A, 100C ¦ 62.9 ¦ 64.8 Rheovibron B' at 60C, MPa 19.1 20.0 Tan Delta at 60~ . 050 . 054 25DIN Abragion 193 180 BXAMPI,E ITI
In this Example, 3, 3 ' -tetrathiodipropanol 30 polysulfide mixture was evaluated as a coupling ayent in a highly silica loaded rubber composition. Rubber compositions c~n~;n;ng the materials set out in Table 5 were prepared in a BR Banbury mixer using three separate, sequential stages of addition, namely, two non-productive mix stages and one productive mix stage to temperatures o~ 160C, 160C and 120C and times of 4 minute~3, 4 minutes and 2 minutes, respectively. The 5 cure behavior and cured properties are indicated in Table 8.
The use o~ 3, 3 ' - tetrathiodipropanol polysulf ide alone or in combination with the conventional coupling agent gave rubber compositions exhibiting excellent 10 cured properties in the presence o~ high levels of silica filler.
T~lble 5 lst~ Non-Pro,.',-ctiy~
15Styrene/Butadiene R~bberl 68 . 75 Polybutadiene Rubber~ 15 . 00 Natural Rub~:1er 35 . 00 Carbon Black3 20 . 00 Silica4 40 . 00 20Zinc Oxide 3 . 00 Fatty Acid 3 00 Antioxidants 2 . 00 Processing Aid6 5 00 3,3'-tetrathiodipropanol sulfide8 4 00 2 5 2nd Nor - Pro~ t ;' ve Silica4 30 . 00 Bis- (3-triethoxysil~lpropyl) 0 or 3 .00 tetrasulfide7 (50~ active) 3,3~-tetrathiodipropanol poly,3ulfide8 0 or 3.00 3 0 Pro~'uct i Ye Sulfur 1.40 Accelerator, sulfenamide type 1. 80 Diphenyl g~ n~ fl; n~ 1. 50 , _ . . .. ..
`, 2180887 1) Emulsion polymerization prepared styrene/butadiene copolymer elastomer cnnt~;nlng 23.5~ bound styrene and 37.5 phr aromatic oil from The Goodyear Tire & Rubber 5 Company;
2) high ci3 1,4-polybutadiene from The Goodyear Tire ~ Rubber Company;
10 3) carbon black as N330;
4) Zeosil 1165 MP from Rhone-Polllenc;
5 ) polymerized 1, 2 - dihydro - 2, 2, 4 -trimethyl~-;nrl ;nP type;
6) Struktol A6;
7) 509~ active composite composed of the organosilane tetrasulfide on or with carbon black in a 50/50 weight ratio available as material X50S from Degussa GmbH.
8 ) 3, 3 ' - tetrathiodipropanol polysul f ide rrnt~;n;n~ 1 to 8 sulfur atom3 in the polysulfide bridge obtained as a highly viscou3 liquid ~rom the reaction of 3-chloropropanol (two molar equivalents) with 1 molar equivalent of aqueous sodium tetrasulfide. It is supported 1 to 1 by weight on N330 carbon black for all examples used in this specif ication .
~ 21 80887 Table 6 5am~1~ # 6 7 X50S (Degussa (~mbH) 3 . O O
3, 3 ~ - tetrathiodipropanol 4 . 0 7 . 0 Rheometer ~150 Cl Max. Torque, dNm 45.0 41.4 Min. Torque, dNm 10 . 0 9 . 0 Delta Torque 35 . 0 32 . 5 T9n~ minutes 17.5 25.0 Stress Str~in Tensile Strength, MPa 13 . 0 11. 9 Elongation at ;3reak, % 474 548 1009~ ~odulus, MPa 2.54 2.0 3009~ Modulus, MPa 8.75 6.14 Re4Qund 100C, ~ 1 52.5 1 46.9 Harr~nloq~
Shore A, 100C ¦ 59.9 ¦ 55.3 Rheovi l'~rQ~
20 E' at 60C, MPa 37.6 35.0 Tan Delta at 60~ . 086 .100 DIN Abrasion 147 161 While certain representative embodiments and 25 details have been shown for the purpose of illustrating the invention, it will be apparent to those skilled in this art that various changes and modif ications may be made therein without departing from the spirit or ~cope of the invention.
~ 21 80887 Table 6 5am~1~ # 6 7 X50S (Degussa (~mbH) 3 . O O
3, 3 ~ - tetrathiodipropanol 4 . 0 7 . 0 Rheometer ~150 Cl Max. Torque, dNm 45.0 41.4 Min. Torque, dNm 10 . 0 9 . 0 Delta Torque 35 . 0 32 . 5 T9n~ minutes 17.5 25.0 Stress Str~in Tensile Strength, MPa 13 . 0 11. 9 Elongation at ;3reak, % 474 548 1009~ ~odulus, MPa 2.54 2.0 3009~ Modulus, MPa 8.75 6.14 Re4Qund 100C, ~ 1 52.5 1 46.9 Harr~nloq~
Shore A, 100C ¦ 59.9 ¦ 55.3 Rheovi l'~rQ~
20 E' at 60C, MPa 37.6 35.0 Tan Delta at 60~ . 086 .100 DIN Abrasion 147 161 While certain representative embodiments and 25 details have been shown for the purpose of illustrating the invention, it will be apparent to those skilled in this art that various changes and modif ications may be made therein without departing from the spirit or ~cope of the invention.
Claims (18)
1. A rubber composition comprised of (A) 100 parts by weight of at least one diene-based elastomer, (B) about 25 to about 100 phr of filler composed of particulate, precipitated silica and carbon black, and (C) a silica coupler selected from (i) 3,3'-tetrathiodipropanol polysulfide mixture containing 1 to 8 sulfur atoms in the polysulfidic bridge or from (ii) a combination of about 95 to about 25 weight percent 3,3'-tetrathiodipropanol polysulfide mixture and, correspondingly, about 5 to about 75 weight percent of bis-(3-trialkoxysilylalkyl) polysulfide containing from 2 to 8 sulfur atoms in its polysulfide bridge wherein the weight ratio of said silica coupler to silica is in a range of about 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 wherein the said silica coupler consists essentially of 3, 3'-tetrathiodipropanol polysulfide mixture; and wherein the weight ratio of said silica coupler to silica is in a range of about 0.01/1 to about 0.2/1
3. The rubber composition of claim 1 where the said 3,3'-tetrathiodipropanol polysulfide mixture is supported on carbon black carrier.
4. The rubber composition of claim 1 wherein the said silica coupler is a combination of about 95 to about 25 weight percent 3,3'-tetrathiodipropanol polysulfide mixture and, correspondingly, about 5 to about 75 weight percent of bis-(3-triethoxysilylpropyl) tetrasulfide and bis-(3-triethoxysilylpropyl ) trisulfide.
5. The rubber composition of claim 1 wherein the diene based elastomer is selected from at least one of cis 1,4-polyisoprene rubber, 3,4-polyisoprene rubber, styrene/butadiene copolymer rubbers, isoprene/butadiene rubber, styrene/isoprene/butadiene terpolymer rubbers, cis 1,4-polybutadiene rubber, medium vinyl polybutadiene rubber, high vinyl polybutadiene rubber and emulsion polymerization prepared styrene/butadiene/acrylonitrile terpolymer rubber and butadiene/acrylonitrile copolymer rubber.
6. The rubber composition of claim 1 wherein the silica is characterized by having a BET surface area in a range of about 50 to about 300 square meters per gram and a dibutylphthalate (DBP) absorption value in a range of about 150 to about 300.
7. The rubber composition of claim 2 wherein the silica is characterized by having a BET surface area in a range of about 50 to about 300 square meters per gram and a dibutylphthalate (DBP) absorption value in a range of about 150 to about 300.
8. The rubber composition of claim 3 wherein the silica is characterized by having a BET surface area in a range of about 50 to about 300 square meters per gram and a dibutylphthalate (DBP) absorption value in a range of about 150 to about 300.
9. A rubber composition comprised of (A) 100 parts by weight of at least one diene-based elastomer, (B) about 25 to about 90 phr particulate silica, (C) up to about 30 phr carbon black, and (D) a silica coupler which is collectively composed of about 90 to about 55 weight percent 3,3'-tetrathiodipropanol polysulfide mixture, about 10 to about 45 weight percent of bis-(3-triethoxysilylpropyl) tetrasulfide and bis-(3-triethoxysilylpropyl) trisulfide wherein the weight ratio of said silica coupler to silica is in a range of about 0.01/1 to about 0.2/1; wherein the weight ratio of silica to carbon black is in a range of about 3/1 to about. 30/1; wherein the silica is characterized by having a BET surface area in a range of about 50 to about 300 square meters per gram and a dibutylphthalate (DBP) absorption value in a range of about 150 to about 300.
10. A tire having a rubber tread wherein said tread is comprised of the rubber composition of claim 1.
11. A tire having a rubber tread wherein said tread is comprised of the rubber composition of claim 2.
12. A tire having a rubber tread wherein said tread is comprised of the rubber composition of claim 3.
13. A tire having a rubber tread wherein said tread is comprised of the rubber composition of claim 4.
14. A tire having a rubber tread wherein said tread is comprised of the rubber composition of claim 5.
15. A tire having a rubber tread wherein said tread is comprised of the rubber composition of claim 6.
16. A tire having a rubber tread wherein said tread is comprised of the rubber composition of claim 7.
17. A tire having a rubber tread wherein said tread is comprised of the rubber composition of claim 8.
18. A tire having a rubber tread wherein said tread is comprised of the rubber composition of claim 9.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/603,113 | 1996-02-20 | ||
| US08/603,113 US5733963A (en) | 1996-02-20 | 1996-02-20 | Silica reinforced rubber composition and tire with tread thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2180887A1 true CA2180887A1 (en) | 1997-08-21 |
Family
ID=24414153
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002180887A Abandoned CA2180887A1 (en) | 1996-02-20 | 1996-07-10 | Silica reinforced rubber composition and tire with tread thereof |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US5733963A (en) |
| EP (1) | EP0791622B1 (en) |
| JP (1) | JPH09227721A (en) |
| BR (1) | BR9700949A (en) |
| CA (1) | CA2180887A1 (en) |
| DE (1) | DE69700849T2 (en) |
| MX (1) | MX9700990A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7977422B2 (en) | 2003-08-11 | 2011-07-12 | Bridgestone Americas Tire Operations, Llc | Non-staining black sidewall |
Families Citing this family (41)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19653938A1 (en) * | 1996-12-21 | 1998-06-25 | Continental Ag | Rubber compound for vehicle tire treads |
| CA2246025A1 (en) * | 1997-09-18 | 1999-03-18 | Giorgio Agostini | Heterogeneous silica carbon black-filled rubber compound |
| US6127472A (en) * | 1997-11-11 | 2000-10-03 | Jsr Corporation | Rubber composition |
| US6053226A (en) * | 1998-03-13 | 2000-04-25 | The Goodyear Tire & Rubber Company | Rubber composition reinforced with silica and tire with tread thereof |
| US6040389A (en) * | 1998-05-28 | 2000-03-21 | The Goodyear Tire & Rubber Company | Bis(hydroxyalkyl alky lester) polysulfides |
| US6518367B1 (en) | 1999-02-25 | 2003-02-11 | The Yokohama Rubber Co., Ltd. | Rubber composition |
| JP2001261891A (en) * | 1999-05-17 | 2001-09-26 | Yokohama Rubber Co Ltd:The | Rubber composition |
| IT1320206B1 (en) | 2000-06-20 | 2003-11-26 | Bridgestone Firestone Tech | METHOD FOR THE PREPARATION OF VULCANIZABLE RUBBER MIXTURES CONTAINING SILICA FOR THE PRODUCTION OF TREAD BANDS. |
| US6359046B1 (en) | 2000-09-08 | 2002-03-19 | Crompton Corporation | Hydrocarbon core polysulfide silane coupling agents for filled elastomer compositions |
| US6458882B1 (en) | 2000-09-14 | 2002-10-01 | The Goodyear Tire & Rubber Company | Silica reinforced rubber composition which contains non-silane coupling agent and article of manufacture, including a tire, having at least one component comprised of such rubber composition |
| US6713549B1 (en) | 2000-09-14 | 2004-03-30 | The Goodyear Tire & Rubber Company | Silica reinforced rubber composition prepared with pre-treated silica article of manufacture, including a tire, having at least one component comprised of such rubber composition |
| MXPA03003245A (en) | 2000-10-13 | 2003-10-15 | Michelin Rech Tech | Rubber composition comprising as coupling agent a polyfunctional organosilane. |
| US6635700B2 (en) | 2000-12-15 | 2003-10-21 | Crompton Corporation | Mineral-filled elastomer compositions |
| US6534584B2 (en) | 2001-01-08 | 2003-03-18 | The Goodyear Tire & Rubber Company | Silica reinforced rubber composition which contains carbon black supported thioglycerol coupling agent and article of manufacture, including a tire, having at least one component comprised of such rubber composition |
| US6797757B2 (en) * | 2001-06-29 | 2004-09-28 | The Goodyear Tire & Rubber Company | Article, including tires, having component or rubber composition which contains particles of pre-vulcanized rubber and blend of tetrathiodipropionic and trithiodipropionic acids |
| US6660791B2 (en) | 2001-06-29 | 2003-12-09 | The Goodyear Tire & Rubber Company | Article, including tires, having component of rubber composition which contains particles of pre-vulcanized rubber and high purity trithiodipropionic acid |
| US6653387B2 (en) | 2001-09-26 | 2003-11-25 | The Goodyear Tire & Rubber Company | Alumina reinforced rubber composition which contains tetrathiodipropionic and/or trithiodipropionic acid coupling agent and article of manufacture, including a tire, having at least one component comprised of such rubber composition |
| US6786476B1 (en) * | 2003-07-21 | 2004-09-07 | The Goodyear Tire & Rubber Company | Airspring |
| US20060131797A1 (en) * | 2004-12-22 | 2006-06-22 | Kerstetter Randal H Iii | Airspring |
| KR100621210B1 (en) | 2005-08-09 | 2006-09-07 | 한국타이어 주식회사 | Analyzing method for silanization yield of silica-compound rubber |
| US7968636B2 (en) * | 2006-12-28 | 2011-06-28 | Continental Ag | Tire compositions and components containing silated cyclic core polysulfides |
| US7960460B2 (en) * | 2006-12-28 | 2011-06-14 | Momentive Performance Materials, Inc. | Free-flowing filler composition and rubber composition containing same |
| US7968635B2 (en) * | 2006-12-28 | 2011-06-28 | Continental Ag | Tire compositions and components containing free-flowing filler compositions |
| US8592506B2 (en) * | 2006-12-28 | 2013-11-26 | Continental Ag | Tire compositions and components containing blocked mercaptosilane coupling agent |
| US7968633B2 (en) * | 2006-12-28 | 2011-06-28 | Continental Ag | Tire compositions and components containing free-flowing filler compositions |
| US7696269B2 (en) | 2006-12-28 | 2010-04-13 | Momentive Performance Materials Inc. | Silated core polysulfides, their preparation and use in filled elastomer compositions |
| US7968634B2 (en) * | 2006-12-28 | 2011-06-28 | Continental Ag | Tire compositions and components containing silated core polysulfides |
| US7781606B2 (en) | 2006-12-28 | 2010-08-24 | Momentive Performance Materials Inc. | Blocked mercaptosilane coupling agents, process for making and uses in rubber |
| US7737202B2 (en) * | 2006-12-28 | 2010-06-15 | Momentive Performance Materials Inc. | Free-flowing filler composition and rubber composition containing same |
| US7687558B2 (en) * | 2006-12-28 | 2010-03-30 | Momentive Performance Materials Inc. | Silated cyclic core polysulfides, their preparation and use in filled elastomer compositions |
| FR2940290B1 (en) | 2008-12-22 | 2010-12-31 | Michelin Soc Tech | BLOCKED MERCAPTOSILANE COUPLING AGENT |
| FR2945815B1 (en) | 2009-05-20 | 2011-07-01 | Michelin Soc Tech | RUBBER COMPOSITION COMPRISING AN ORGANOSILANE COUPLING AGENT |
| FR2947552B1 (en) | 2009-05-20 | 2011-08-26 | Michelin Soc Tech | ORGANOSILANE COUPLING AGENT |
| DE102012100321B4 (en) * | 2011-02-18 | 2018-02-15 | Toyo Tire & Rubber Co., Ltd. | A process for producing a rubber composition, rubber composition, vulcanized product and use of a rubber composition in an air-filled tire |
| EP2517898A1 (en) | 2011-04-29 | 2012-10-31 | Lanxess Deutschland GmbH | Rubber mixtures containing silicic acids with additives containing sulphur |
| EP2671727A1 (en) | 2012-06-06 | 2013-12-11 | LANXESS Deutschland GmbH | Rubber mixtures containing silicic acids with additives containing sulphur |
| EP2671726A1 (en) | 2012-06-06 | 2013-12-11 | LANXESS Deutschland GmbH | Rubber mixtures containing silicic acids with additives containing sulphur |
| EP2684912A1 (en) | 2012-07-09 | 2014-01-15 | LANXESS Deutschland GmbH | Mélanges de caoutchouc avec acide silique contenant de l'ester w-mercaptocarboxylique d'alcools polyvalents |
| ITTO20120953A1 (en) * | 2012-10-29 | 2014-04-30 | Bridgestone Corp | METHOD FOR THE PREPARATION OF A RUBBER COMPOUND FOR TIRES |
| ITRM20120646A1 (en) * | 2012-12-18 | 2014-06-19 | Bridgestone Corp | METHOD FOR THE PREPARATION OF RUBBER COMPOUNDS FOR TIRES |
| DE102019213978A1 (en) * | 2019-09-13 | 2021-03-18 | Continental Reifen Deutschland Gmbh | Sulfur-crosslinkable rubber mixture, vulcanizate and vehicle tires |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB921810A (en) | 1961-02-15 | 1963-03-27 | Pittsburgh Plate Glass Co | Improvements in and relating to vulcanizates |
| US3664403A (en) | 1969-07-07 | 1972-05-23 | Ppg Industries Inc | A vulcanized rubber comprising a siliceous pigment, a rubber and an organic coupling agent having an active olefinic linkage |
| US3884285A (en) | 1971-10-08 | 1975-05-20 | Ppg Industries Inc | Abrasion-resistant rubber compositions |
| US3768537A (en) | 1972-11-09 | 1973-10-30 | Ppg Industries Inc | Tire |
| GB1424503A (en) | 1973-03-05 | 1976-02-11 | Cabot Corp | Precipitated silica reinforcing agents and rubber compositions containing same |
| US3938574A (en) | 1973-10-11 | 1976-02-17 | Deutsche Gold- Und Silber-Scheideanstalt Vormals Roessler | Vulcanizable rubber mixture for tire treads having improved skid resistance |
| US4482663A (en) | 1982-07-12 | 1984-11-13 | Phillips Petroleum Company | Rubber compositions comprising a siliceous filler in combination with an organosulfur substituted pyridine promotor |
| FR2562534B1 (en) | 1984-04-06 | 1986-06-27 | Rhone Poulenc Chim Base | NOVEL PRECIPITATED SILICA WITH IMPROVED MORPHOLOGICAL CHARACTERS, PROCESS FOR OBTAINING THE SAME AND APPLICATION THEREOF, IN PARTICULAR AS FILLER |
| FR2589871B1 (en) | 1985-09-13 | 1987-12-11 | Rhone Poulenc Chim Base | REINFORCING FILLER FOR SILICA-BASED ELASTOMER |
| DE4038589A1 (en) | 1990-12-04 | 1992-06-11 | Bayer Ag | RUBBER VULCANISTS WITH GOOD MECHANICAL PROPERTIES AND IMPROVED HYSTERESIS BEHAVIOR |
| CA2104529A1 (en) * | 1993-06-18 | 1994-12-19 | Paul Harry Sandstrom | Tire with silica reinforced tread |
| US5605951A (en) * | 1996-02-20 | 1997-02-25 | The Goodyear Tire & Rubber Company | Silica reinforced rubber compostition and tire with tread thereof |
| US5610216A (en) * | 1996-02-20 | 1997-03-11 | The Goodyear Tire & Rubber Company | Silica reinforced rubber composition and tire with tread thereof |
-
1996
- 1996-02-20 US US08/603,113 patent/US5733963A/en not_active Expired - Lifetime
- 1996-07-10 CA CA002180887A patent/CA2180887A1/en not_active Abandoned
-
1997
- 1997-02-07 MX MX9700990A patent/MX9700990A/en unknown
- 1997-02-10 JP JP9026274A patent/JPH09227721A/en active Pending
- 1997-02-11 EP EP97102134A patent/EP0791622B1/en not_active Expired - Lifetime
- 1997-02-11 DE DE69700849T patent/DE69700849T2/en not_active Expired - Fee Related
- 1997-02-13 BR BR9700949A patent/BR9700949A/en active Search and Examination
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7977422B2 (en) | 2003-08-11 | 2011-07-12 | Bridgestone Americas Tire Operations, Llc | Non-staining black sidewall |
Also Published As
| Publication number | Publication date |
|---|---|
| MX9700990A (en) | 1997-08-30 |
| BR9700949A (en) | 1998-09-01 |
| EP0791622A1 (en) | 1997-08-27 |
| JPH09227721A (en) | 1997-09-02 |
| US5733963A (en) | 1998-03-31 |
| EP0791622B1 (en) | 1999-12-01 |
| DE69700849D1 (en) | 2000-01-05 |
| DE69700849T2 (en) | 2000-06-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |