Patent Application
20080066840
Rubber compositions were prepared for evaluating an effect of an inclusion of a rubber composition which contains a dispersion of corncob granules for a specialized transition layer for a tire tread.
Sample A is a Control rubber sample. Experimental rubber Samples B through G contained various amounts of a corncob granule dispersion.
The rubber compositions were prepared by mixing the ingredients in sequential non-productive (NP) and productive (PR) mixing steps in one or more internal rubber mixers.
The basic recipe for the rubber Samples is presented in the following Table 1 and recited in parts by weight unless otherwise indicated.
1Emulsion polymerization prepared styrene/butadiene rubber as PLF1712 ™ from The Goodyear Tire & Rubber Company having a bound styrene content of about 23.5 percent
2Cis 1,4-polybutadiene rubber (prepared by organic solvent solution polymerization) as Budene 1207 ™ from The Goodyear Tire & Rubber Company having a cis 1,4-microstructure of at least about 97 percent
3Rubber reinforcing carbon black as N299, an ASTM designation
4Rubber processing oil and microcrystalline wax
5Fatty acid comprised (composed) of at least 90 weight percent stearic acid and a minor amount of other fatty acid comprised (composed of) primarily of palmitic and oleic acids.
6Antidegradant of the phenylenediamine type
7Corncob granules as 60 Grit-O′ cobs ® from The Andersons, Inc.
The following Table 2 illustrates cure behavior and various physical properties of rubber compositions based upon the basic recipe of Table 1.
1Data according to Moving Die Rheometer instrument, model MDR-2000 by Alpha Technologies, used for determining cure characteristics of elastomeric materials, such as for example Torque, T25, etc.
2Data according to Automated Testing System instrument by the Instron Corporation which incorporates six tests in one system. Such instrument may determine ultimate tensile, ultimate elongation, modulii, etc. Data reported in the Table is generated by running the ring tensile test station which is an Instron 4201 load frame.
3Data according to Rheometric Dynamic Spectrometer analytical instrument.
4Data according to Rubber Process Analyzer as RPA 2000 ™ instrument by Alpha Technologies, formerly the Flexsys Company and formerly the Monsanto Company. References to an RPA-2000 instrument may be found in the following publications: H. A. Palowski, et al, Rubber World, June 1992 and January 1997, as well as Rubber & Plastics News, Apr. 26 and May 10, 1993.
5Data obtained according to a tear strength (peal adhesion) test to determine interfacial adhesion between two samples of a rubber composition. In particular, such interfacial adhesion is determined by pulling one rubber composition away from the other at a right angle to the untorn test specimen with the two ends of the rubber compositions being pulled apart at a 180° angle to each other using an Instron instrument at 95° C. and reported as Newtons force.
It can be seen from Table 2 that the compound (rubber composition) stiffness (100% modulus, dynamic moduli G′ and Shore A hardness) is increased with the introduction of corncob granules into the compound when the carbon black loading (50 and 70 phr) is maintained.
This is considered herein to be significant in a sense that the presence of the corncob granule dispersion is seen to provide some reinforcement to the rubber compound.
It can also be seen from Table 2 that the hysteretic properties (tan delta at 30° C. and 100° C.) of the compound are not significantly affected with the introduction of the corncob granular dispersion into the compound when the carbon black loading (50 and 70 phr) is maintained.
This is considered herein to be significant in a sense that the heat build up characteristics (the aforesaid hysteretic property) of the compound is substantially maintained with the introduction of the corncob granule dispersion into the rubber compound.
Rubber compositions were prepared for evaluating an effect of an inclusion of corncob granules where the compound Shore A hardness was kept similar for a specialized transition layer for a tire tread.
Sample H is a Control rubber sample. Experimental rubber Samples I through K contained various amounts of a corncob granule dispersion.
The rubber compositions were prepared by mixing the ingredients in sequential non-productive (NP) and productive (PR) mixing steps in one or more internal rubber mixers.
The basic recipe for the rubber Samples is presented in Table 1 of the previous Example I. For this Example II, the corn cob granule content of the rubber compositions was from zero for the Control Sample H and a range of from 7.5 to 25 phr for the experimental Samples J through K.
The following Table 3 illustrates cure behavior and various physical properties of rubber Samples H through K.
It can be seen from Table 3 that the hysteretic properties (tan delta at 30° C. and 100° C.) of the compound are improved (reduced) and rebound value is increased (improved) with the introduction of the corncob granular dispersion into the rubber composition with the Shore A hardness property remaining similar. The Shore A hardness (10° C.) for the experimental Samples I, J and K remained the same as the corn cob granule concentration increased from 7.5 phr to 25 phr and was similar or the same as the Shore A hardness (100° C.) as the Control H Sample which did not contain the corn cob dispersion.
This is considered herein to be significant in a sense that the heat build up characteristics (the aforesaid hysteretic property) of the compound is improved (reduced) by the introduction of the corncob granule dispersion into the rubber composition while its stiffness (Shore A hardness) is maintained.
While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention.
