US008247487B2 (12) United States Patent (10) Patent No.: US 8,247.487 B2 Bethea et al. (45) Date of Patent: Aug. 21, 2012 (54) TIRE WITH TREAD CONTAINING 5,462.979 A 10/1995 Sandstrom .................... 523,438 CARBOXYLATED STYRENEABUTADENE 5.488,077 A 1/1996 Sandstrom ..... ... 523,438 RUBBER 5,489,627 A 2, 1996 Sandstrom ..... 523/213 5,489,628 A 2, 1996 Sandstrom ..... 523/213 6.218.473 B1 * 4/2001 Sandstrom ..... 525, 191 (75) Inventors: Robert Anthony Bethea, North Canton, 6,365,668 B1 * 4/2002 Scholl et al. ... 524/575 OH (US); Paul Harry Sandstrom, 6,852,794 B2* 2/2005 Puhala et al. .. ... 524,588 Cuyahoga Falls, OH (US) 7,144,465 B2 12/2006 Nanni et al. ... 156,110.1 s 7,816.483 B2 10/2010 Hogan et al. ... 528,125 2003. O195288 A1 10, 2003 Robert et al. .. ... 524/492 (73) Assignee: The Goodyear Tire & Rubber 2011/0048599 A1* 3/2011 Ryba et al. ................. 152,209.5 Company, Akron, OH (US) FOREIGN PATENT DOCUMENTS (*) Notice: Subject to any disclaimer, the term of this EP 6O1611 12/1993 patent is extended or adjusted under 35 EP 704481 4f1996 U.S.C. 154(b) by 21 days. EP 1493597 1, 2005 EP 20983.84 9, 2009 KR 20040089349 10, 2004 (21) Appl. No.: 12/944,196 KR 20110O33322 3, 2011 (22) Filed1C N OW. 11,II, 2010 WO 2005/056665 6, 2005 OTHER PUBLICATIONS (65) Prior Publication Data European Search Report completed Mar. 20, 2012. US 2012/O123017 A1 May 17, 2012 * cited by examiner (51) Int. Cl. He;hy 3.08: Primary Examiner — Hui Chin (52) U.S. Cl. ...................................sos.soss, (74) Attorney, Agent, or Firm Henry C. Young, Jr. (58) Field of Classification Search ................... 524/495 See application file for complete search history. (57) ABSTRACT (56) References Cited This invention relates to a tire with a tread of a rubber com position containing carboxylated Styrene/butadiene rubber. U.S. PATENT DOCUMENTS 4,398,582 A 8, 1983 Yuto et al. ................. 152,209 R 7 Claims, No Drawings US 8,247,487 B2 1. 2 TRE WITH TREAD CONTAINING (1) from about 10 to about 65 phr of carboxylated styrene/ CARBOXYLATED STYRENEABUTADENE butadiene rubber (x-SBR), and RUBBER (2) about 35 to about 90 phr of additional elastomer(s), (other than said carboxylated styrene/butadiene rubber), FIELD OF THE INVENTION comprised of at least one of Solution polymerization prepared styrene/butadiene rubber (S-SBR), or emul This invention relates to a tire with a tread of a rubber sion polymerization prepared styrene/butadiene rubber composition containing carboxylated Styrenefbutadiene rub (E-SBR), wherein said solution polymerization pre ber. pared styrene/butadiene rubber may be a functionalized 10 Solution polymerization prepared styrene/butadiene BACKGROUND OF THE INVENTION rubber (f-S-SBR), (B) about 50 to about 150, alternately about 80 to about Vehicular tires typically have treads of rubber composi 130, phr of particulate reinforcing filler comprised of rubber tions comprised of selected elastomers and particulate rein 15 reinforcing carbon black. forcing fillers. Preferably said tread rubber composition does not contain Such elastomers may typically include cis 1,4-polybutadi any appreciable amount of precipitated silica reinforcement ene rubber to promote, for example, resistance to treadwear, (e.g. less than about 5 phr) and more preferably is exclusive of styrene/butadiene rubber to promote, for example, wet trac precipitated silica reinforcement. tion and sometimes natural rubber to promote, for example, It is intended that said rubber composition is exclusive of heat durability for the tire tread. Sometimes functionalized carboxylated nitrile rubber (x-NBR). elastomers have been proposed such as, for example amine Where appropriate, said functionalized solution polymer and siloxy functionalized styrene/butadiene rubbers. For ized styrene/butadiene rubber (f-S-SBR) may be, for example, see U.S. Pat. No. 7,816.483. example, functionalized solution polymerized styrene/buta For this invention, however, an emphasis is placed on pro 25 diene rubber (S-SBR) containing at least one functional viding a tire tread which might be suitable, for example, for a group comprised of amine functional group, siloxy functional tire in which tread traction (e.g. skid resistance) is most group, combination of amine and siloxy functional groups, important and resistance to tread wear is of lesser importance combination of thiol and siloxy functional groups, combina such as, for example, for a vehicle which may be desired to tion of imine and siloxy functional groups, hydroxyl func travel at relatively high speeds. 30 tional group, and epoxy group. For Such purpose, it is proposed that the rubber composi In practice, the vinyl 12-content of the X-SBR may range, tion be exclusive of any appreciable amount of, and prefer for example, from about 20 to about 50 percent based upon its ably exclusive of cis 1,4-polybutadiene rubber and natural polybutadiene portion. rubber. It should readily be understood by one having skill in the For Such purpose, it is proposed that a rubber composition 35 art that said tread portion of the pneumatic tire, as well as the for a tiretread be evaluated for which its elastomer constituent rubber or other material in the basic carcass, which normally is limited to a functionalized elastomer Such as, for example, contains reinforcing elements in the tread region, can be a carboxylated nitrile rubber (x-NBR) or carboxylated sty compounded by methods generally known in the rubber com rene/butadiene rubber (x-SBR). pounding art, such as mixing the various Sulfur-Vulcanizable In the description of this invention, the terms “rubber' and 40 constituent rubbers with various commonly-used additive "elastomer if used herein, may be used interchangeably, materials such as, for example, curing aids, such as Sulfur, unless otherwise prescribed. The terms “rubber composi activators, retarders and accelerators, processing additives, tion”, “compounded rubber' and “rubber compound, ifused Such as oils, resins including tackifying resins, and plasticiz herein, are used interchangeably to refer to “rubber which has ers, fillers, pigments, Stearic acid, Zinc oxide, waxes, antioxi been blended or mixed with various ingredients and materi 45 dants and antioZonants and reinforcing materials, namely the als” and such terms are well known to those having skill in the aforesaid rubber reinforcing carbon black. As known to those rubber mixing or rubber compounding art. skilled in the art, depending on the intended use of the sulfur The term “phr where used herein, and according to con Vulcanizable and sulfur-Vulcanized materials (rubbers), the ventional practice, refers to “parts of a respective material per certain additives mentioned above are selected and com 100 parts by weight of rubber, or elastomer'. 50 monly used in conventional amounts. The Tg of an elastomer, if referred to herein, refers to an Such pneumatic tires are conventionally comprised of a onset glass transition temperature of the rubber which can generally toroidal-shaped carcass with an outer circumferen conveniently be determined by a differential scanning calo tial tread, adapted to be ground contacting, spaced beads and rimeter at a heating rate of 10° C. per minute. For example, sidewalls extending radially from and connecting said tread See ASTMD-1356-98. 55 to said beads. A softening point of a resin, where appropriate, is deter It is readily understood by those having skill in the art that mined by “Ring and Ball” ASTM No. E28. the rubber composition of the tread rubber would be com pounded by methods generally known in the rubber com SUMMARY AND PRACTICE OF THE pounding art, such as mixing the various Sulfur-Vulcanizable INVENTION 60 constituent rubbers with various commonly used additive materials such as, for example, curing aids, such as Sulfur, In accordance with this invention, a tire is provided having activators, retarders and accelerators, processing additives, a circumferential tread of a sulfur cured rubber composition Such as oils, resins including tackifying resins, silica, and which comprises, based on parts by weight per 100 parts by plasticizers, fillers, pigments, fatty acid, Zinc oxide, waxes, weight of rubber (phr): 65 antioxidants and antioZonants and peptizing agents. As (A) 100 phr of conjugated diene-containing elastomer known to those skilled in the art, depending on the intended comprised of: use of the sulfur-Vulcanizable and sulfur-Vulcanized material US 8,247,487 B2 3 4 (rubbers), the additives mentioned above are selected and The mixing of the rubber composition can be accom commonly used in conventional amounts. plished by methods known to those having skill in the rubber In practice, the tire, as a manufactured article, may be mixing art. For example, the ingredients may be mixed in at prepared by shaping and Sulfur curing the assembly of its least two stages, namely, at least one non-productive stage components at an elevated temperature (e.g. 140°C. to about 5 followed by a productive mix stage. The final curatives are 160° C.) and elevated pressure in a suitable mold. Such prac typically mixed in the final stage which is conventionally tice is well known to those having skill in Such art. called the “productive” mix stage in which the mixing typi Typical amounts of reinforcing filler for this invention, cally occurs at a temperature, or ultimate temperature, lower namely rubber reinforcing carbon black, is hereinbefore men than the mix temperature(s) than the preceding non-produc tioned. Typical amounts of processing aids, if used, may 10 tive mix stage(s). The terms “non-productive' and “produc comprise, for example, about 1 to about 50 phr. Such process tive' mix stages are well known to those having skill in the ing aids can include, for example, aromatic, naphthenic, and/ rubber mixing art.