Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
• • 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
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
  • C08L9/06—Copolymers with styrene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
  • C08L9/02—Copolymers with acrylonitrile

Definitions

• This invention relates to tire tread compositions having high abrasion resistance, high traction and low rolling resistance.
• treads of modern tires must meet performance standards which require a broad range of desirable properties.
• rubber compositions suitable for tire treads should exhibit not only desirable strength and elongation, particularly at high temperatures, but also good cracking resistance, good abrasion resistance, desirable skid resistance and low tan delta values at low frequencies for desirable rolling resistance. Additionally, a high complex dynamic modulus is necessary for maneuverability and steering control.
• Major tire manufacturers have developed tread compounds which provide lower rolling resistance for improved fuel economy and better skid/traction for a
• S-SBR solution styrene butadiene rubber
• E-SBR emulsion styrene butadiene rubber
• Cis BR Cis polybutadiene
• HV-BR high vinyl content polybutadiene
• U.S. Patent 4,894,420 is directed to tire treads having cis 1,4-polyiso ⁇ rene, at least one copolymer containing acrylonitrile rubber, and a rubber based on polybutadiene.
• U.S. Patent 4,791,178 refers to a tire tread composition of at least 30% of a conjugated diene-monovinyl aromatic hydrocarbon copolymer.
• U.S. Patent 4,866,131 refers to a rubber composition for use in tires containing a high styrene SBR.
• Patent 4,616,685 refers to tire treads containing a plasticizing ester, a styrene-butadiene rubber having more than 25% styrene by weight, and a second rubber ingredient chosen from butyl rubber, butyl halide rubber, butadiene/acrylonitrile copolymer, or mixtures thereof.
• U.S. Patent 4,433,094 refers to tire treads having a particular type of carbon black, styrene-butadiene rubber having a specific bound styrene content, and optionally another diene rubber.
• Patent 4,788,241 refers to a curing system comprised of a curative, a paraffin wax and pentaerythritol tetrastearate, which is said to cure rubbers such as natural rubber, cis-polyisoprene, polybutadiene, solution and emulsion poly(styrene-butadiene) , EPDM, poly(acrylonitrile-butadiene) , and mixtures thereof.
• a curative a paraffin wax and pentaerythritol tetrastearate
• rubbers such as natural rubber, cis-polyisoprene, polybutadiene, solution and emulsion poly(styrene-butadiene) , EPDM, poly(acrylonitrile-butadiene) , and mixtures thereof.
• the rubber portion of the tire tread composition comprises: i) a first rubber component comprising about 5-15 parts of nitrile-butadiene rubber (NBR) per hundred parts of rubber (phr) ; ii) a second rubber component comprising about 43-95 phr of styrene butadiene rubber (SBR); and iii) a third rubber component comprising 0-47 phr of high cis polybutadiene (cis BR) rubber.
• NBR nitrile-butadiene rubber
• SBR styrene butadiene rubber
• compositions may also include suitable amounts of other ingredients such as carbon black, aromatic oil, zinc oxide, stearic acid, sulfur, sulfur donor compounds, sulfur cure accelerators, waxes, antiozonants, etc.
• the rubber portion of the tire tread comprises either a two component mixture of SBR and NBR, or a three component mixture of SBR, cis BR and NBR, in the relative amounts previously stated.
• the relative amounts of SBR and cis BR should be such that the SBR component forms the continuous phase.
• the rubber components of the present invention are all known and commercially available.
• a particularly suitable NBR material having an acrylonitrile content of 38.5-40.9%, is sold under the name PARACRIL® CJLT (trademark of the Uniroyal Chemical Company), and referred to hereinafter as CJLT.
• Another suitable NBR material is known as PARACRIL® BJLT (trademark of the Uniroyal Chemical Company), and referred to hereinafter as BJLT.
• This material has an acrylonitrile content of 31.4-33.8%.
• any solution or emulsion SBR may be used in the present invention.
• solution SBR is preferred.
• an SBR having a low bound styrene content for example not more than about 24%, since the use of NBR in the present invention allows use of lower bound styrene contents than generally used commercially.
• Particularly suitable is a solution SBR with a bound styrene content of about 18%, and an emulsion SBR with a bound styrene content of about 23.5%, both of which are available commercially.
• the curative system employed in the present invention for the rubber portion is any suitable system known in the art, and may include sulfur and/or a sulfur donor compound, and at least one sulfur cure accelerator. If sulfur is used, it is preferably present in an amount of between about 1.0-3.0 parts per hundred parts of rubber.
• sulfur donor compounds which may be employed in conjunction with or in the alternative to sulfur are well known to those skilled in the art of rubber compounding.
• Illustrative of such sulfur donor compounds are 2-(4-morpholinyldithio)-benzothiazole, tetramethylthiuram disulfide, tetraethylthiuram disulfide, dipentamethylene thiuram hexasulfide, N,N'-caprolactam disulfide and the like.
• sulfur cure accelerators which may be employed include thioureas, such as N,N'-dibutylthiourea,
• the sulfur cure accelerator is generally present in amounts of between about 0.1 part and about 5 parts per 100 parts of rubber, with preferably between about 0.3 part and about 3.0 parts of accelerator per 100 parts of rubber being present. Most preferably, between about 0.3 part and about 1.5 part of accelerator per 100 parts of rubber are employed.
• the tire tread composition of this invention may further comprise zinc oxide, reinforcing agents, fillers, processing aids, extender oils, plasticizers, antidegradants, and the like, all of which additional components are well known to those skilled in the rubber art.
• zinc oxide per hundred parts of rubber are employed, although amounts in excess of 10 parts may also be employed. Most preferably, between about 3 and about 5 parts of zinc oxide per 100 parts of rubber are present.
• Tables III and IV The results of such testing are summarized in Tables III and IV below.
• PICO abrasion was measured following procedures given in ASTM D-2228; Tensile Strength, Elongation, and Modulus were measured following procedures in ASTM D412.
• tensile and modulus values in Table III are given in psi units, whereas in Table IV they are given in MPa units. It is known to one skilled in the art that 1 psi equals .006895 MPa.
• the Tear Die C values in Table III are in pounds per inch (ppi), whereas in Table IV they are given in KN/m. It is known to one skilled in the art that 1 ppi equals .175 KN/m.
• Examples 1-4 illustrate the two component rubber compositions of the present invention.
• Examples 5-6 illustrate the three component rubber compositions of the present invention.
• Example A represents a control sample included for comparative purposes.
• Examples 3 and 4 are similar to Examples 1 and 2 except that a different type of nitrile rubber is used in the compounding, namely Paracril® BJLT, which has an acrylonitrile content of 31.4-33.8%.
• Examples 5 and 6 are examples of the three component blends of the present invention.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Tires In General (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (2)

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ID=24805185

Family Applications (1)

Country Status (11)

Cited By (5)

Families Citing this family (12)

Family Cites Families (5)

• 1992
  • 1992-04-15 CA CA002109202A patent/CA2109202A1/en not_active Abandoned
  • 1992-04-15 DE DE69213002T patent/DE69213002T2/de not_active Expired - Fee Related
  • 1992-04-15 AT AT92911793T patent/ATE141631T1/de not_active IP Right Cessation
  • 1992-04-15 BR BR9205985A patent/BR9205985A/pt not_active IP Right Cessation
  • 1992-04-15 EP EP92911793A patent/EP0583369B1/en not_active Expired - Lifetime
  • 1992-04-15 WO PCT/US1992/003016 patent/WO1992020737A2/en not_active Ceased
  • 1992-04-15 KR KR1019930703373A patent/KR100188355B1/ko not_active Expired - Fee Related
  • 1992-04-15 JP JP4510883A patent/JP2682740B2/ja not_active Expired - Fee Related
  • 1992-04-21 TW TW081103125A patent/TW197462B/zh active
  • 1992-05-08 MX MX9202157A patent/MX9202157A/es not_active IP Right Cessation
  • 1992-05-09 CN CN92103440A patent/CN1048510C/zh not_active Expired - Fee Related

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