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
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
  • C08K3/20—Oxides; Hydroxides
  • C08K3/22—Oxides; Hydroxides of metals
• • 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
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
  • C08K3/013—Fillers, pigments or reinforcing additives
• • 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
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/30—Sulfur-, selenium- or tellurium-containing compounds

Definitions

• This invention relates generally to vulcanizable elastomeric compounds having enhanced viscoelastic properties, and, more particularly, to improved elastomeric compositions having 100 parts by weight of at least one diene-based elastomer and from
• fillers which include compounds of zinc, barium and/or titanium.
• Elastomeric compounds are so-called viscoelastic materials. This means that the properties which they exhibit depend on the duration (time or frequency) and on the temperature at which external stresses or deformations (strains) are applied to them.
• Pertinent viscoelastic parameters which are measured in laboratory tests, are the elastic moduli, E ' (in tension or compression) and G ' (in shear), the viscous moduli E" (in tension or compression) and G" (in shear), and the ratio of the viscous and elastic moduli, otherwise known as the loss tangent or tan ⁇ . These parameters are determined under dynamic conditions at specific temperatures, frequencies, strain rates, and stress- or strain- amplitudes. Another important parameter is the glass transition temperature, T g , which is the temperature below which the elastomeric composition becomes "glasslike" or brittle.
• these viscoelastic parameters can be determined with great precision, and these parameters can be confidently correlated to practical performance characteristics in, say, tires.
• the tan ⁇ 5of a compound measured within a temperature range of about 50-70 °C, correlates directly with the rolling resistance of a tire. That is, the lower the tan ⁇ , the lower the rolling resistance of a tire tread.
• the magnitude of the tan ⁇ or E measured at about 0 °C, or at the respective T g of a tire tread compound, relate to certain traction characteristics of a tire, whereas the magnitude of the tan r5at very low temperatures of about -65 °C is indicative of the abrasion or wear characteristics of a tire tread.
• an improved elastomeric composition includes 100 parts by weight of at least one diene-based elastomer, and from 30 to 160 phr of filler, the filler comprising at least about 7 phr of zinc sulfate.
• an improved elastomeric composition includes 100 parts by weight of at least one diene-based elastomer, and from 30 to 160 phr of filler, the filler comprising at least 7 phr barium sulfate.
• the improved elastomeric composition includes 100 parts by weight of at least one diene-based elastomer, and from about 30 to 160 parts of filler, the filler comprising at least 8 phr titanium dioxide, and also containing at least one compound selected from the group consisting of silica, carbon black, clay, calcium carbonate, and talc.
• the mean particle size of zinc sulfate, barium sulfate and titanium dioxide particles is between about 0.2 and 1.6 microns and accounts for between 10 and 30 weight percent of the filler.
• the general object of the invention is to provide improved vulcaniz- able elastomeric compositions.
• Another object is to provide improved elastomeric compositions employing zinc sulfate, barium sulfate or titanium dioxide as filler material.
• the present invention deals with a novel compounding technology through the use of a new class of additives. As a result, the opposing property trends of conventional elastomeric compounds are minimized, while the overall performance level of com- pounds is greatly improved.
• the nature of the elastomer determines the basic properties of vulcanizable elastomeric compounds. With current technologies, these properties are modified by the kind and amount of compounding ingredients that are used. These ingredients include processing aids, fillers, softeners, vulcanizing chemicals, chemicals protecting against aging, blowing agents, etc. All these conventionally-used materials are compatible with compounds of the present invention. However, the present invention uses an new group of compounding aids to achieve the desired novel balance and level of viscoelastic properties.
• Commonly-used elastomers which are compatible with the novel compounding technology of this invention, include natural rubber, or synthetic elastomers, based on mono, copolymers orterpolymers from butadiene, isoprene, isobutylene, styrene, acrylo- nitrile, chlorobutadiene, ethylene, propylene, dicyclopentadiene, ethylene norbornene, hexadiene, vinyl acetate, chlorosulfonyl ethylene, epichlorohydrin, ethylene oxide, or propylene oxide.
• Blends from these elastomers can also be employed within useful blend ratios.
• fluoroelastomers, silicone rubbers, polysulfide rubbers, and polyurethane rubbers are also compatible with the compounding technology of this invention.
• Fillers which are compatible with the novel compounding technology of this invention can be generally classified as carbon blacks or light-colored fillers.
• the carbon blacks comprise a wide range of grades, and there is no restriction on surface area, surface activity, particle size, or aggregate structure.
• Light fillers include colloidal silica, calcium silicate, aluminum silicate, alumina gel, clay, talcum, or calcium carbonate (i.e., chalk). Again, there is no restriction on the particle size, aggregate size, or the surface activity of these light fillers.
• the surface activity of carbon blacks and light fillers can also be modified with appropriate chemicals according to current technologies. It is also possible to employ blends of carbon black grades, light fillers, or carbon blacks and light fillers in compounds of the present invention.
• plasticizers it is also possible to use plasticizers, process aids, factices, mineral oils, bonding resins, reinforcing resins, tackifiers, blowing agents and various aging-, fatigue-, and ozone- protective agents.
• the elastomeric compositions of this invention can be vulcanized using current technologies. These include accelerated sulfur systems, sulfur donors, peroxides, curing resins and high energy radiation. Combinations of any of these systems can also be employed.
• current technologies include accelerated sulfur systems, sulfur donors, peroxides, curing resins and high energy radiation. Combinations of any of these systems can also be employed.
• the following examples will illustrate the nature of the novel compounding technology. In these examples, all compounds contained 100 parts by weight of at least one diene-based elastomer.
• All compounds had the same type and concentration of elastomers, namely a blend of two solution SBR's (synthetic styrene-butadienejubber), and the same sulfur/ accelerator cure system, protective agents, oils, and process aids.
• the total filler concentration was held constant at 35% by weight throughout, but different filler types were used.
• Compound A (Control 1) is a modern low-rolling-resistance, high traction passenger tire tread, based on the latest silica compounding technology.
• the filler was a blend of 45 phr silica with a surface area of 180 m 2 per gram of silica.
• the surface of the silica was modified with a silane coupling agent and of 25 phr carbon black (ASTM grade N134), which has a high surface area and high structure (i.e., degree of aggregation of primary particles).
• Compound B (Control 2) is a modern long-wearing, high-traction passenger tread compound using carbon black filler only (70 phr of ASTM Grade N134).
• Compound C (Control 3) is a modern high-traction, low-rolling-resistance passenger tread using carbon black filler with lower surface area than that of Control 1 (a blend of 35phr of ASTM GradeN343 carbon black, and 35 phr of ASTM Grade N351 carbon black).
• Compounds D, E and F were compounded using the novel technology of this invention.
• the fillers in Compound D were 61.5 phr carbon black (i.e., blend of N343 and N351) plus 8.5 phr zinc sulfate with mean particle size of 0.7 microns.
• the fillers were 61.7 phr carbon black (blend of N343 and N351) plus 8.3 phr barium sulfate with mean particle size of 1.6 microns.
• the fillers were 60.8 phr carbon black (blend of N343 and N351) plus 9.2 phr titanium dioxide of mean particle size of 0.2 microns.
• the viscoelastic properties of these six compounds were determined using a Rheometrics RS A dynamic tester in uniaxial extension over a temperature range from - 70 °C to +60 °C, and a dynamic strain amplitude of 0.5% with a 10% prestrain at a frequency of 10 Hertz. From these measurements, the glass transition temperature T g and the tan lvalues at -25 °C, 0 °C and 50 °C were determined. These data are summarized in Table 1 :
• Compound A (Control 1) is based on the latest silica compounding technology to give a very low-rolling-resistance, high traction passenger tire tread,.
• the filler was a blend of 45 phr silica with a surface area of 180 m 2 per gram of silica.
• the surface of the silica was modified with a silane coupling agent and of 25 phr carbon black
• Compound B (Control 2) represents a long-wearing, high-traction passenger tread compound using carbon black filler only (70 phr N134).
• Compounds C, D and E were compounded using the novel technology of this invention.
• the fillers in Compound C were 61.5 phr carbon black (N134) plus 8.5 phr zinc sulfate with mean particle size of 0.7 microns.
• the fillers were 61.7 phr carbon black (Nl 34) plus 8.3 phr barium sulfate with mean particle size of 1.6 microns.
• the fillers were 60.8 phr carbon black (N134) plus 9.2 phr titanium dioxide of mean particle size of 0.2 microns.

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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)

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• 1999
  • 1999-04-22 EP EP99918784A patent/EP1208142A1/de not_active Withdrawn
  • 1999-04-22 CA CA002367674A patent/CA2367674A1/en not_active Abandoned
  • 1999-04-22 AU AU36616/99A patent/AU3661699A/en not_active Abandoned
  • 1999-04-22 WO PCT/US1999/008838 patent/WO2000064968A1/en not_active Application Discontinuation

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