Tread compounds with highly-dispersible silica.A wide variety of particulate par·tic·u·late adj. Of or occurring in the form of fine particles. n. A particulate substance. particulate composed of separate particles. fillers is used in the rubber industry to improve the physical properties of rubber compounds. The most common polymer used in truck tire tread tread injury to the coronet of the horse's hoof by treading on it by the opposite hoof, or by another horse when they are being worked in a team. If the coronary matrix is injured there may be a subsequent crack or deformity. compounds is natural rubber (NR). In most cases, carbon black is the dominant filler fill·er 1 n. One that fills, as: a. Something added to augment weight or size or fill space. b. A composition, especially a semisolid that hardens on drying, used to fill pores, cracks, or holes in wood, plaster, used to impart the abrasion abrasion /abra·sion/ (ah-bra´zhun) 1. a rubbing or scraping off through unusual or abnormal action; see also planing. 2. a rubbed or scraped area on skin or mucous membrane. resistance, traction Traction Definition Traction is the use of a pulling force to treat muscle and skeleton disorders. Purpose Traction is usually applied to the arms and legs, the neck, the backbone, or the pelvis. and durability necessary for good tire performance. Silica silica or silicon dioxide, chemical compound, SiO2. It is insoluble in water, slightly soluble in alkalies, and soluble in dilute hydrofluoric acid. Pure silica is colorless to white. , as well as other specialty fillers, has been reported to improve specific properties Specific properties of a substance are derived from other intrinsic and extrinsic properties (or intensive and extensive properties) of that substance. For example, the density of steel (a specific and intrinsic property) can be derived from measurements of the mass of a steel bar of passenger tire tread compounds when used in conjunction with carbon black (refs. 1-15). Silica has been widely investigated as the primary filler for passenger tire treads, which have the desirable properties of low rolling-resistance with good traction (refs. 16-37). Passenger tires have successfully introduced to the marketplace the improved processing and abrasion resistance of highly dispersible silica (HDS (Hitachi Data Systems, Santa Clara, CA, www.hds.com) A leading provider of high-end storage hardware, software and services. Part of the Information Systems & Telecommunications Division of Hitachi Ltd. ) fillers in compounds containing high vinyl vinyl /vi·nyl/ (vi´nil) the univalent group CH2dbondCH—. vinyl chloride a vinyl group to which an atom of chlorine is attached; the monomer which polymerizes to polyvinyl chloride; it is toxic solution-polymerized SBR SBR - Spectral Band Replication . These desirable properties have been shown to result from the improved dispersion dispersion, in chemistry dispersion, in chemistry, mixture in which fine particles of one substance are scattered throughout another substance. A dispersion is classed as a suspension, colloid, or solution. , as evidenced by the absence of particles [is greater than] 1 [micro]m as measured by microscopic microscopic /mi·cro·scop·ic/ (mi?kro-skop´ik) 1. of extremely small size; visible only by the aid of the microscope. 2. pertaining or relating to a microscope or to microscopy. techniques (ref. 23 and 32-37). Previously, precipitated silica had been used in combination with carbon black to improve the performance of a truck tire tread compound (ref. 38). Chakravarty and coworkers (ref. 39) found that for a 60 phr N231 carbon black-filled, natural rubber heavy-service truck tire tread, use of 30 phr of precipitated silica and a mercaptosilane couplig agent at 1% of the precipitated silica level as a direct replacement for carbon black increased the resistance to cutting and chipping. Higher levels of precipitated silica could be used without a significant sacrifice in heat build-up build·up also build-up n. 1. The act or process of amassing or increasing: a military buildup; a buildup of tension during the strike. 2. and treadwear by using the mercaptosilane coupling agent. Wolff (ref. 40) reported that rolling resistance Rolling resistance, sometimes called rolling friction or rolling drag, is the resistance that occurs when an object such as a ball or tire rolls. It is caused by the deformation of the wheel or tire or the deformation of the ground. was reduced by 30%, wet traction virtually unchanged and the treadwear index was decreased only by 5% when a silane-modified precipitated silica was used to replace N220 carbon black in a natural rubber truck tread. Huybrechts (ref. 41) used 20 phr of precipitated silica as a replacement for N234 carbon black in a styrene-butadiene rubber formulation formulation /for·mu·la·tion/ (for?mu-la´shun) the act or product of formulating. American Law Institute Formulation for truck tire retreads in order to improve rolling resistance and tear properties. Experimental Silica physical properties were measured in accordance Accordance is Bible Study Software for Macintosh developed by OakTree Software, Inc.[] As well as a standalone program, it is the base software packaged by Zondervan in their Bible Study suites for Macintosh. with ASTM ASTM abbr. American Society for Testing and Materials and/or ISO (1) See ISO speed. (2) (International Organization for Standardization, Geneva, Switzerland, www.iso.ch) An organization that sets international standards, founded in 1946. The U.S. member body is ANSI. procedures, when available, as shown in table 1. The physical properties of the silicas used are shown in table 2. They include: * a highly-dispersible silica; * a silica characterized char·ac·ter·ize tr.v. character·ized, character·iz·ing, character·iz·es 1. To describe the qualities or peculiarities of: characterized the warden as ruthless. 2. as easily-dispersible: * a conventional silica; and * a novel highly dispersible silica.
Table 1 - test methods for physical properties of silicas
Property tested Procedure
B.E.T. surface area ASTM D1993
CTAB surface area Huber standard test
pH, 5% slurry ASTM D1512
Linseed oil absorption Rub-out method
Average projected area ASTN D3849
Table 2 - physical properties of silicas used
Property Silica
A B
Classification Highly- Easily-
dispersible dispersible
B.E.T. surface area, [m.sup.2]/g 186 195
CTAB surface area, [m.sup.2]/g 144 145
pH, 5% slurry 7.0 7.1
Linseed oil absorption, [cm.sup.3]/100g 199 236
Average projected area, [nm.sup.2] 2,890 ***
Property Silica
C D
Classification Conventional Highly-
dispersible
B.E.T. surface area, [m.sup.2]/g 178 132
CTAB surface area, [m.sup.2]/g 141 81
pH, 5% slurry 6.6 7.2
Linseed oil absorption, [cm.sup.3]/100g 211 73
Average projected area, [nm.sup.2] 6,780 3,098
The rubber formulation used was based on a model natural rubber truck tire formulation (ref. 42) shown in table 3. Unless the coupling agent was being investigated, the level of bifunctional bi·func·tion·al adj. 1. Having two functions: bifunctional neurons. 2. Chemistry Having or involving two functional groups or binding sites: silane silane or silicon hydride Any of a series of inorganic compounds of silicon and hydrogen with covalent bonds and the general chemical formula SinH(2n + 2). , bis-(3-triethoxysilylpropyi)-tetrasulfide, and the level of diphenyl diphenyl /di·phen·yl/ (di-fen´il) a toxic compound comprising two linked benzene rings, used as a fungistat in containers for shipping citrus fruits. di·phen·yl n. See biphenyl. guanidine guanidine /gua·ni·dine/ (gwah´ni-den) the compound NHdbondC(NH2)2, a strong base found in the urine as a result of protein metabolism and used in the laboratory as a protein denaturant. curative curative /cur·a·tive/ (kur´ah-tiv) tending to overcome disease and promote recovery. cu·ra·tive adj. 1. Serving or tending to cure. 2. have been adjusted relative to the silica level in an attempt to provide similar cross-link density for each compound. Relative compound cross-link density was estimated from the % volume swell
Roughly speaking, the sound of a guitar note is characterised by an initial 'attack' where the pick or nail produces higher pitched of cured rebound rebound (rē´bownd), n/v 1. a recovery from illness. n 2. an outbreak of fresh reflex activity after withdrawal of a stimulus rebound adjective block samples in toluene toluene (tōl`y  ēn') or methylbenzene (mĕth'əlbĕn`zēn), C7H8 after 24 hours at 25
[degrees]. All compounds were mixed using a laboratory internal mixer mixer, either of two electronic devices in which two or more signals are combined. In the type of mixer used in radio receivers, radar receivers, and similar systems, a signal is translated upward or downward in frequency. and two-roll mill in accordance with ASTM 1)3182. Rubber processability
was measured using a Mooney viscometer viscometerInstrument for measuring the viscosity (resistance to internal flow) of a fluid. In one type, the time taken for a given volume of fluid to flow through an opening is recorded. according to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. ASTM D1646. Silica dispersion was estimated by the % white area at 1,000x magnification Magnification A measure of the effectiveness of an optical system in enlarging or reducing an image. For an optical system that forms a real image, such a measure is the lateral magnification m using a Dispergrader 1000 with optional silica scale. Rubber cure properties were tested using an oscillating os·cil·late intr.v. os·cil·lat·ed, os·cil·lat·ing, os·cil·lates 1. To swing back and forth with a steady, uninterrupted rhythm. 2. the rheometer rhe·om·e·ter n. An instrument for measuring the flow of viscous liquids, such as blood. in accordance with ASTM D2084. All compounds were cured to [T.sub.90] + appropriate mold mold, name for certain multicellular organisms of the various classes of the kingdom Fungi, characteristically having bodies composed of a cottony mycelium. The colors of molds are caused by the spores, which are borne on the mycelium. lag and physical properties of the cured compounds were tested using the test procedures shown in table 4. Table 3 - model natural rubber tread compound formulation Ingredient phr Natural rubber, SIR10 100.0 N110 carbon black 50.0 varied Silica - varied X50S - varied 6PPD antiozonant 2.0 Agerite resin D 2.0 Paraffin wax 1.5 Aromatic processing oil 4.0 Stearic acid 2.0 Zinc oxide 4.0 Sulfur 1.75 CBS 1.75 PVI 0.5 DPG - varied Table 4 - rubber test procedures Property tested Test procedure Stress/strain ASTM D412 Tear ASTM D624 Abrasion resistance ISO 4649 Rebound D1504 Tangent delta @ 60 [degrees] C Monsanto RPA Results and discussion A [2.sup.4] factorial factorial For any whole number, the product of all the counting numbers up to and including itself. It is indicated with an exclamation point: 4! (read “four factorial”) is 1 × 2 × 3 × 4 = 24. design was carried out to investigate the region of interest. The factors and levels selected were: * Total filler level, investigated at 40 and 70 phr; * % of the total filler which is silica, investigated at 0% and 100% silica (concurrent with DPG DPG diphosphoglycerate. at 2.5% of the silica by weight); * % X50S coupling agent relative to the silica weight, investigated at 0% to 12% coupling agent: and * silica type, A or D. As was expected, all variables were statistically significant for most rubber properties with statistically significant interactions. For most properties, this range of variables was sufficient to provide a broad range of useful compounds for NR truck tread compounds. A series of [2.sup.3] factorial designs with replicated centerpoints was carried out using the above variables with each of the silica types. In order to achieve a range of 300% modulus See modulo. values equivalent to the carbon black filled compound, the maximum coupling agent level was increased to 15%. The levels of each variable are shown in table 5. Significant predictions at [Alpha] = 0.05 from the analysis of these designs for increasing the total filler level are shown in tables 6-9. As expected, the increase in filler, whether silica or carbon black, increases the hardness of the compound with resultant This article is about the resultant of polynomials. For the result of adding two or more vectors, see Parallelogram rule. For the technique in organ building, see Resultant (organ). In mathematics, the resultant of two monic polynomials effects on other measured properties (table 6). The effects of replacing carbon black for silica on a part-for-part basis (partially confounded with coupling agent effects) is shown in table 7. A significant observation is the increase in rebound at 25 [degrees] C and 100 [degrees] C, while the rebound at -27 [degrees] C is decreased. The significant effects of changing silane level relative to silica level, within the limits of the design, shown in table 8, are expected. Increasing coupling agent increased the modulus of the compound and decreased the viscosity. Table 9 shows the effects of changing silica type. Conven-tional silica (C) is assigned a value of 0 and those silicas which have properties which are statistically different from C at [Alpha] = 0.10 are designated by a + if the value is raised and a - if the value is lowered. If the differences are statistically significant at [Alpha] = 0.05, the symbols ++ or -- are used. The advantages of highly dispersible silica (A) over conventional silica are seen for lowered viscosity, increased modulus, increased tensile strength tensile strength Ratio of the maximum load a material can support without fracture when being stretched to the original area of a cross section of the material. When stresses less than the tensile strength are removed, a material completely or partially returns to its and increased elongation elongation, in astronomy, the angular distance between two points in the sky as measured from a third point. The elongation of a planet is usually measured as the angular distance from the sun to the planet as measured from the earth. at break. The easily-dispersible silica (C) has intermediate properties as found in previous evaluations in solution SBR compounds (ref. 43). The novel highly dispersible silica (D) has much superior viscosity and modulus properties with some loss of tensile tensile, adj having a degree of elasticity; having the ability to be extended or stretched. and elongation.
Table 5 - experimental design levels for 2(3) design, series 1
Silicas used A B D
Variable -1 level 0 level +1 level
Total filler 40 55 70
Silica as % of filler 20 50 80
X50S as % of Silica 5 10 15
Table 6 - significant effects of increasing total filler level
Rubber property affected Effect
Shore A hardness Increase
Minimum torque Increase
Maximum torque Increase
Mooney viscosity Increase
[TS.sub.2] scorch Increase
Tangent delta Increase
Rebound Decrease
Modulus Increase
Tensile Decrease
Elongation Decrease
Table 7 - effect of increasing silane coupling agent level
Rubber property affected Effect
Delta torque Increase
Mooney viscosity Decrease
Modulus Increase
Table 8 - effects of increasing silica as percent of total filler
Rubber property affected Effect
Shore A hardness Decrease
Maximum torque Decrease
Mooney viscosity Increase
[TS.sub.2] scorch Increase
[T.sub.50] and [T.sub.90] cure time Increase
Tangent delta @ 60 [degrees] C Decrease
Rebound @ RT, 100 [degrees] C Increase
Rebound @ -27 [degrees] C Decrease
Modulus Decrease
Tensile Decrease
Elongation Increase
Table 9 - effect of various silica types on rubber properties
Rubber property Silica type
A B C D
Minimum torque - + 0 --
Delta torque 0 0 0 +
Mooney viscosity - 0 0 --
Tangent delta @ 60 [degrees] C 0 0 0 -
Rebound @ RT, 100 [degrees] C 0 0 0 -
Modulus + + 0 ++
Tensile ++ + 0 -
Elongation @ break + 0 0 -
Confirmation batches were mixed to investigate direct comparisons of predicted trends. Silicas A, C and D were used at 52.5 phr with 10.5 phr X50S (10% by weight of silane per silica weight). Results are shown in table 10 versus the 50 phr N110 black control (with no silane coupling agent). All silicas increased the viscosity and lengthened length·en tr. & intr.v. length·ened, length·en·ing, length·ens To make or become longer. length  en·er n. the
[T.sub.90] cure time compared to black, with silica D having the least
effect. Tensile strength, tear strength and abrasion resistance were
significantly lower for silica C. Silica D had the highest 300% modulus
and abrasion resistance with significantly lower tangent tangent, in mathematics.1 In geometry, the tangent to a circle or sphere is a straight line that intersects the circle or sphere in one and only one point. delta @ 60 [degrees] C than carbon black or the other silicas. Table 11 shows the results for the silicas at 52.5 phr using 6.3 phr X50S (6% by weight silane per silica weight). At the lower silane level, silicas A and C showed dramatic increases in Mooney and lower tensile, modulus and abrasion resistance. Significantly, silica D showed far fewer differences in these properties from the 10% silane sample.
Table 10 - silica type comparison (52.5 phr silica, 10.5 phr X 50S)
10% silane/silica weight/weight
Silica type A D C
Mooney viscosity 69.5 61 73.5
[TS.sub.2] scorch time, min. 5 6 5.3
T50 cure time, min. 9.8 9.4 10.2
T90 cure time, min. 15.5 14.4 16.1
Tangent delta @ 60 [degrees] C 0.113 0.089 0.12
300% modulus, MPa 11.7 12.2 11.3
Tensile, MPa 24.8 25.2 19.9
Elongation at break, % 567 553 512
Rebound @ 100 [degrees] C, % 68.8 70.2 68
Rebound @ -27 [degrees] C, % 10 9.8 10.1
Tear, N/m 22.1 24.1 17.4
DIN abrasion, index 104 114 90
Black, control
(50 phr
N110 black,
no silane)
Mooney viscosity 56
[TS.sub.2] scorch time, min. 8
T50 cure time, min. 9.8
T90 cure time, min. 11.9
Tangent delta @ 60 [degrees] C 0.121
300% modulus, MPa 12.8
Tensile, MPa 27.2
Elongation at break, % 559
Rebound @ 100 [degrees] C, % 66.2
Rebound @ -27 [degrees] C, % 11.2
Tear, N/m 18.7
DIN abrasion, index 122
Table 11 - 52.5 phr silica, 6.3 phr X50S)
A D C
Mooney viscosity 81.9 66.4 89.3
[TS.sub.2] scorch time, min. 4.4 6.2 5.7
T50 cure time, min. 9.6 10 14.2
T90 cure time, min. 16.4 13.7 20.7
Tangent delta @ 60 [degrees] C 0.111 0.095 0.124
300% modulus, MPa 11.0 11.9 10.0
Tensile, MPa 22.5 24.5 19.2
Elongation at break, % 831 881 732
Rebound @ 100 [degrees] C, % 59.8 73 62.5
Rebound @ -27 [degrees] C, % 10.8 9.6 10.2
Tear, N/m 31.5 40.9 21.3
DIN abrasion, index 91 112 73
Black control
(50 phr
black, no
silane)
Mooney viscosity 56
[TS.sub.2] scorch time, min. 8
T50 cure time, min. 9.8
T90 cure time, min. 11.9
Tangent delta @ 60 [degrees] C 0.121
300% modulus, MPa 12.8
Tensile, MPa 27.2
Elongation at break, % 559
Rebound @ 100 [degrees] C, % 66.2
Rebound @ -27 [degrees] C, % 11.2
Tear, N/m 18.7
DIN abrasion, index 122
Each of the silicas were mixed in a blend with carbon black at 52.5 phr total filler loading at 25% silica/75% carbon black, 50% of each filler, 75% silica/25% carbon black and 100% silica using 8% by weight of silica of the silane coupling agent and adjusting DPG relative to the silica weight. The responses for Mooney viscosity, 300% modulus, DIN abrasion index and tangent delta @ 60 [degrees] C are shown in figures 1-4, respectively. The advantages of silica D at all levels are evident. Note that after a 50/50 blend the tangent delta tends to level off and the modulus continues to decrease while the viscosity increases. There is no convincing evidence of specific interactions such as those found with sSBR compounds (ref. 43). From estimates of the responses generated from the data, an optimum formulation to achieve the closest match to N110 carbon black properties of modulus and tensile were mixed. All silicas were mixed at 30 phr silica and 30 phr carbon black using 4.8 phr X50S (8% silane by weight of silica). The compounds formulated for·mu·late tr.v. for·mu·lat·ed, for·mu·lat·ing, for·mu·lates 1. a. To state as or reduce to a formula. b. To express in systematic terms or concepts. c. with silica D provided equivalent cure, modulus and abrasion resistance to the black control with significantly lower tangent delta @ 60 [degrees] C and higher hot rebound as shown in table 12. [Figures 1-4 ILLUSTRATION OMITTED] Table 12 - based with carbon black (30 phr silica/30 phr carbon black, 4.8 phr X50S)
A D C
Mooney viscosity 70.6 59.4 71.9
[TS.sub.2] scorch time, min. 5.9 5.9 5.2
T50 cure time, min. 6.9 8.1 8
T90 cure time, min. 11.6 10.3 14.1
Tangent delta @ 60 [degrees] C 0.096 0.072 0.101
300% modulus, MPa 11.4 12.4 10.2
Tensile, MPa 27.9 26.8 20.6
Elongation at break, % 871 944 814
Rebound @ 100 [degrees] C, % 68.2 76 64
Rebound @ -27 [degrees] C, % 10 10.2 10.5
Tear, N/m 26.3 32.7 20.2
DIN abrasion, index 110 128 86
Black control
(50 phr
black, no
silane)
Mooney viscosity 56
[TS.sub.2] scorch time, min. 8
T50 cure time, min. 9.8
T90 cure time, min. 11.9
Tangent delta @ 60 [degrees] C 0.121
300% modulus, MPa 12.8
Tensile, MPa 27.2
Elongation at break, % 559
Rebound @ 100 [degrees] C, % 66.2
Rebound @ -27 [degrees] C, % 11.2
Tear, N/m 18.7
DIN abrasion, index 122
Conclusions The partial replacement of carbon black with silica in a natural rubber truck tread has been demonstrated. The advantages of the highly dispersible silicas A and D are evident at all levels, particularly for abrasion resistance and tensile and tear properties. The level of silane coupling agent must be matched to the silica to provide the proper modulus properties. Silica D provides the best match to N110 carbon black for all properties at lower levels of coupling agents than conventional or currently available highly dispersible silicas. [Figure 5 ILLUSTRATION OMITTED] References (1.) C. Dragus, B. Mehr and S. Florea, RO 95946 B1 (9/15/ 88). (2.) R. Scriver and W.H. Stair to Goodyear, U.S. 4,522,970 (6/11/85). (3.) H. Hayashi and Y. Nomura to Toyo, JP 0430247 A2 (10/27/92). (4.) H. Nakamura and S. Furusawa to Ohtsu, JP 60139728 A2 (7/24/85). (5.) L. Gonzalez-Hernandez, L.M.I. Rueda and C.C. Anton, Rubber Chem. Technol., 60, 606 (1987). (6.) S.N. Chakravarty, A.L. Kapur, S.N. Sau and M. Mittal, Rubber India, 33, 11 (1981). (7.) E.J. Stewart, J. Elastomers Plastics, 9, 439 (1977). (8.) S. Ahmad and R.J. Schaefer to B.F. Goodrich, U.S. 4,519,430 (5/28/85). (9.) S. Wolff, Tire Sci. Technol., 15, 276 (1987). (10.) C.J. Derham, P. Newell and P. McL. Swift, NR Technol., 19, 1 (1988). (11.) T.S. Mroczkowski to Pirelli Armstrong, U.S. 5,162,409 (11/10/92). (12.) J.T. Byers, Tire Technol. Int. '93, 58 (1993). (13.) P.H. Sandstrom, R.G. Bauer, D.J. Burlett and M.S. Sinsky to Goodyear, U.S. 5,328,949 (7/12/94). (14.) P.H. Sandstrom, R.G. Bauer, D.J. Burlett and M.S. Sinsky to Goodyear, U.S. 5,336, 730 (8/9/94). (15.) L.G. Wideman and P.H. Sandstrom to Goodyear, U.S. 5,434,206 (7/18/95). (16.) C.C. Stueber, III to PPG PPG Points Per Game (basketball player statistic) PPG Power Play Goals (hockey) PPG Planning Policy Guidance (UK) PPG Programmable Pulse Generator PPG Power Puff Girls , U.S. 3,451,458 (6/24/69). (17.) T.J. Doran, M.P. Wagner and H.C. Stevens to PPG, U.S. 3,664,403 (5/23/72). [18.) T.J. Doran, M.P. Wagner and H. C. Stevens to PPG, U.S. 3,737,334 (6/5/73). (19.) R.H. Hess, H.H. Hockje, J.R. Creasey and F. Strain to PPG, U.S. 3,768,537 (10/30/73). (20.) D.B. Russell and T.J. Doran to PPG, U.S. 3,884,285 (5/20/75). (21.) D.B. Russell and T.J. Doran to PPG, U.S. 3,994,742 (11/30/76). (22.) N. Shimada, I. Hattori, M. Sakakibara, N. Oshima, T. Hamada, H. Fukuoka and T. Fujimaki to Japan Synthetic Rubber synthetic rubber: see rubber. and Bridgestone, U.S. 4,894,409 (1/16/90). (23.) R. Rauline to Michelin, U.S. 5,227,425 (7/13/93). (24.) J. Bergh, M. Kunio and J.-C.J. Kihn to Goodyear, U.S. 5,447,971 (9/5/95). (25.) P.H. Sandstrom, D.J. Zanzig, J.J. Verthe and M.J. Crawford to Goodyear, E.P. 0623650 A1 (4/25/94). (26.) R.J. Zimmer, Y.A. Bernard, U.E. Frank, W. Lauer, T.F. Materne and F. Visel to Goodyear, E.P. 0631982 (6/20/94). (27.) D.J. Zanzig, P.H. Sandstrom, M.J. Crawford, J.J. Verthe and C.A. Losey to Goodyear, E.P. 0638610 A1 (7/27/94). (28.) B.D.W. Powell to Sumitomo, E.P. 0643099 A1 (8/19/94). (29.) D.J. Zanzig, P.H. Sandstrom, M.J. Crawford, J.J. Verthe and C.A. Losey to Goodyear, E.P. 0641823 A1 (8/25/94). (30.) G. Agostini, J. Bergh and Th. Materne, "New compound technology," Akron Rubber Group, October 27, 1994. (31.) J.-C.J. Kihn, J. Bergh, M. Junio, T.D. Linster and J.-P. Lambotte to Goodyear, E.P. 0645423 A1 (3/29/95). (32.) F. Bomo, Y. Chevallier, P. Lamy and J.-C. Morawski to Rhone Poulenc, U.S. 5,089,554 (2/18/92). (33.) P. Cochet, P. Barruel, L. Barriquand, J. Grobert, Y. Boreal bo·re·al adj. 1. Of or relating to the north; northern. 2. Of or concerning the north wind. 3. Boreal and E. Prat, Rubber World, 210, p. 20 (1994). (34.) W.H. Waddell, P.A. Beauregard and L.R. Evans, Tire Technol. Int. '95, 14 (1995). (35.) L.R. Evans, J.T. Dew dew, thin film of water that has condensed on the surface of objects near the ground. Dew forms when radiational cooling of these objects during the nighttime hours also cools the shallow layer of overlying air in contact with them, causing the condensation of some , L.T. Hope, T.G. Krivak and W.H. Waddell, Rubber & Plastics News, July 31, 1995, p. 12. (36.) L.R. Evans and W.H. Waddell, Kautsch. Gummi Kunstst., 48, 718 (1995). (37.) Ph. Cochet, L. Barriquand, Y. Bomal and S. Touzet, "Precipitated silica in tire tread," presented at the ACS (Asynchronous Communications Server) See network access server. Rubber Division Meeting, Cleveland, OH, October, 1995. (38.) P. Stevens and A. Chanse to Sumitomo, U.S. 5,208,276 (5/4/93). (39.) S.N. Chakravarty, A.L. Kapur, S.N. Sau and M. Mittal, Rubber India, 33, 11 (1981). (40.) S. Wolff, "Silica-based tread compounds: Background and performance," presented at TyreTech'93, Basel, Switzerland, October, 1993. (41.) F. Huybrechts, Kautsch. Gummi Kunstst., 48, 713 (1995). (42.) W.H. Waddell, "Pneumatic tire Noun 1. pneumatic tire - a tire made of reinforced rubber and filled with compressed air; used on motor vehicles and bicycles etc pneumatic tyre bicycle wheel - the wheel of a bicycle compounding," in The Vanderbilt Rubber Handbook, R.F. Ohm, Editor, R.T. Vanderbilt Company, Inc., Norwalk, CT, 1990, p. 604. (43.) W.C. Fultz and L.R. Evans "Tire tread compounds with silica/carbon black blends," presented at the ACS Rubber Division Meeting, Anaheim, CA, May, 1997. by Larry R. Evans and William C. Fultz, J.M. Huber Corp. |
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