CA1114088A - Low hysteresis-rubber compositions - Google Patents

Abstract

Abstract of the Disclosure Rubbery compositions containing a carbon black having a tint residual of -6 or less and a tint in the range of from about 70 to 100 exhibit low hysteresis.

Description

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LOW HYSTERESIS-RUBBER CO~POSITION

mis is a division of patent application Serial No. 268,033, filed December 16, 1976. mis invention relates to carbon black. In a mDre specific aspect, this invention relates to rubker com2ositions containin~ carbon black.
Furtherm~re, the invention relates to carbon black reactors in which carbon blacks can be made.
Background of the Invention A broad variety of carbon blacks have been disclosed in the art.
These blacks differ in many properties from each other and are made by different procedures. The main field of use of the blacks depends upon their properties. Since the carbon black as such cannot be sufficiently character-ized by its chemical composition or by its ingredients, it has become widely accepted to characterize the carbon black by the properties it exhibits. Thus the carbon black can, e.g., be characterized by its surface area which is, as usually, an inverse measurement of the nodule size. Another important character-istic of the carbon black is its structure, which is a measure of the complexity of the individual carbon black aggregates or of the number of nodules "fused"
together in one carbon black aggregate.
Great efforts have been made in the industry to correlate properties of rubbers incorporating carbon black and properties of carbon black. Unfor-tunately, there is not one single property of carbon black that, if made highor low enough, results in an ideal rubber composition. Certain properties of carbon black are related to abrasion of the rubber composition; others are relates to the tensile strength; others are related to the heat buildup.
Efforts have been made to correlate the tint or tinting strength of carbon black to the abrasion resistance of rubbers. In this connection the statement has been made that high-tint carbon black incorporated in rubber ;~ results in highly abrasion-resistant rubber compositions. As will be shown, no such correlation exists.
High abrasion resistance of a carbon black/rubber composition is one desirable property of such a composition. Another desirable property ;s low heat buildup or low hysteresis. The heat buildup is a measurement of how :~ . . .

much of the elastic deformatlon energy put into a carbon blacklrubber c~mpo-~itlon remaln~ in this composition a~ heat sfter the deformation forces have been released. The hysteresis, or heat buildup, i8 measu~ed by mea~uring the temperature of a sample subJected to deformations. m is property, hysteresls, of carbon blacklrubber compo~ltlons is very important, particularly for tires made with such a composition. The hlgher the heat buildup, the grester the chances are that tires made from such rubbers are destroyed or even begin to burn. Serlous accldents hsve been attrlbuted to the failure of ~ires made from ~uch hlgh heat buildup rubber composltlons. It would, therefore, be very desirable to reduce the heat buildup of rubber/carbon black co~positions.
The Invention It iB thus one obJect of this invention to provlde a carbon black which, lncorporated in rubber, causes low heat buildup of the rubber compo-sitlon.
Another ob~ect of this lnvention iB to provide a carbon blsck which, when incorporated in rubber, results in a rubber composltlon havlng both a ; low hest builtup and a high abrasion resi~tance.
A further ob~ect of this lnvention iR to provide a rubber composition having a low heat bulldup.
~Qt another obJsct o this invention is to provide a rubber compo-sltlon having both low heat buildup snd hlgh abrasion re~lstance.
These and other detalls, advnntages, embodiments and features of the present lnventlon will become spparent to those Rkillet in the art from the following detailed descriptlon of the invention, the appended claims and the drawing, ln whlch FIGS. 1 and 3 are longltudlnal cros~ sectlons through two carbon black resctore, and FIG. 2 iR a cro~s section through the reactors ~hown ln FIGS. 1 and 3.
In accord~nce w~th the lnvention, there 1~ now provided a novel . .

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carbon black characterized by having a tint resldual of about -6 or less.
The tlnt residual i8 a property of the carbon black defined by the fol~owlng formula:
TR - T - t56.0 ~ 1.057 ~CTAB) - 0.002745 ~CTAB)2 ~ 0.2596 tDBP) - 0.201 (N2SA

-- CTAB) ] .
In this formula, the abbreviat~ons used have the followi~g meaningY and the properties are measured ~ descrlbed:
TR: This le tlnt residual.

CTAB: Thls le the eurface srea of the csrbon black measured as described by J. Janzen and G. Kraus in Rubber Chemlstry ant Technology, 44, 1287 (1971), m2/gm.

N2SA: Thls iY the ~urface area of the c~rbon black measured using nltrogen in accordance wlth the ASTM method D-3037-71T, m2/gm.
DBP: This i8 the structure of the c~rSon black in cc/100 8 and i8 measuret in accordance wlth U.S. Patent 3,S48,454 and~
after cru~hing, by method B in accordance wlth ASTM D-2414-70. This property i~ also referred to as 24M4 DBP.
T2 Thls 18 the tint or tintlng strength of the carbon black mQasured by arbitrsrily asslgnlnR the reference black IRB
No. 3 the value of 100 the tlnt is measured ln accord~nce with ASTM 3265-75.
Among the c~rbon blac~s definet by the formula given above, those that ~e f~rthQr characterized by having surface area and structure propertles wlthin the following ranges aro particularly preferred:
CTAB: 73 to 140 square meters~g~am D~P: 67 to 111 cc¦100 g (N2SA - CTAB): 23 square meters/gram or less All thcse properties, namely CTAB~ DBP and N2SA, are defined and measured as dieclosed ~bove.
For best overall performsnc~ in rubber co~positions, n carbon blac~
8~ teflnod above i8 pre~ently pr~ferred that hae a tint resldual TR ne defined o~ -6 to -20.

In accordance with another embodiment of this inventio~, there i8 provid2d a rubber composition exhibiting both low h~at buildup and satis-, ., - . .
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fsctory tresd wear properties. Thi8 rubber conposition comprlses 100 parts by welght of rubber and 30 to 120 parts by weight of a carbon black havlng a tlnt resldual of about -6 or less. The tlnt residual 18 defined n~ above.
The preferred rubber composltion6 are those lncorporatlng the preferred carbon blacks as deflned above.
The Nbber in the rubber composltion of this invention can be natural rubber or a synthetlc rubber. Among the synthetlc rubbers the polymers and copolymers of at least one con~ugated acyclic alkadiene ha~lng 4 to 8 carbon atom~, as well as the copolymers of at least one conJugatet acycllc alkadiene having 4 to 8 carbon atoms and at least one monovlnyl arene with the vinyl wbstituent attached to an arene rlng csrbon atom are presently preferred.
Partlcularly preferred are polymers and copolymers of butadlene, lsoprene and plperylene with styrene or a methylstyrene.
Yet more specifically, and in accordance with another embodiment of I this inv~ntion, there is provlded 8 rubber composltion whlch is partlculsrly useful for tire tread appllcations and whlch 18 essentially composed of ingredients and quantltles 88 shown Sn the following tabulatlon, contalning Sn addltSon standard addlti~es ~uch a8 antioxitants, etc.:
Tread Black Rubber Parts by Welght Rubber 100 Carbon black 65-90 Extender oll 15-65 ,~ The carbon black in thi~ co~positlon is, again, defined by havlng a tlnt residual of -6 or less.
Similarly, and in accordance with still a further embotiment of this I lnventi~n, a rubber compo~ition i8 provlded which i8 particularly applicable ', in the tire carcass applications. Thls ru~ber composition consists essentially i, of the ingredlent~ listed in the following tabulation and, in addition, also contains ~tandard additives such as antloxidants, etc.:
Carcass Blnck Rubber Parts by Weight Rubber 100 Carbon b~aek 30-60 E~tender oll 5-lO
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In thls carcass rubber compo~ition, too, the carbon black i~ deflned by having a tint residual of -6 or le88.
In accordance with 8tlll ~ further embodiment of this lnvention, there i8 provided a carbon black reactor ln which the low tint resldual carbon bl~ck can be msde. This c~rbon black reactor i8 ba~lcally a tubular carbon black reactor with a wlde precombustlon ~ection followed by a narrow first redction section which in turn is followed by a wider second reaction ~ectlon.
The dlameter of the precombustlon section 18 about 9 to 12 lnches, whereas the axial length of thls precombustlon section 1~ about 3 to about 6 lnches.
The first recctlon sectlon, whlch i8 a narrow sectlon, has an upstream dismeter of about 2 to 4 lnches and an axlal len~th of about 3 to 15 inches. The second reactlon section has an upstream dlameter whlch i8 about 2 to 5 times a8 wlde ~8 the downstresm ~lameter of the first reac~lon section, 80 that ~he cross sectlon of the reaction sectlons abruptly witens from sald first section to ~ait ~econd sectlon. Means for generatlng a hot combustlon 8a~ vortex in the precombustlon seotion, as well as mesns for lntroduclng hydrocarbon feed-stock are provided for. The hydrocnrbon feedstock can be introtuced either at the ax~s snd at the upstream con~ining wall of the precorbustion section or can be lntroduced st a locatlon at the tubular reactor wall withln the down-str~sm portion of the first reactlon sectlon or at the reactor wall ln theproxl~ity of the sbrupt dlameter change from the fir~t to the second reactlon ~ection.
; The flrot reactlon sectlon, ln accords~ce with 8 first embodlment of thls reactor ln accordsnce with ehls inventlon, 1~ about 3 to 8 lnchec long ~nd fru~toconlcally ~haped. The first reaction sectlon in this embodlment conVergeB in down~tream direction at an sngle between the reactor axls and the frustoconlcal surf~ce ln the range o$ a~out 10 to about 18 degrees, and the downstrea~ dla~eter of this flrst reactlon section 1~ about 1 to 2 inche~.
In another embod~ment of the reactor of thls inventlon, the firet r~Qction ~ection 18 e~sentlally a cylindrical reactlon ~ectlon having a venturi-~haped choke therein. The length of the flr~t reaceion section in ~4~

thls embod~ment 18 about 6 to 18 inches, and the venturi-shaped choke located at the upstream portlon of the firse reaction section is about 3 to about 9 inches long in axlal dlrection. The throat diameter of the venturl-shaped choke is about 1 to 2 inches~
The ~nvent~on wlll be ~till re fully under~to~d from the de~crlp-tlon of the reactors, as well as the specific examples.
In the drawlng, two specific reactors sre shown ln cro~s section.
FIGS. 1 ~nt 2 show a tubular carbon black reactor confined by n shell 1 of heat-rssistant materlal ~uch a~ cera~ic. The lnternal shape of the reactor 18 eosentially rotatlonally ~ymmetric around the reactor BX~S 2. The reactor 1~ composed of a precombustion s~ction 3, a first reaction section 4 ~nd a second reaction section 5. All theee sections are in open communlcatlon, axially allgned and operatlvely connected wlth each other. The fir~t reactlon ~ectlon 4 i8 essentially a frustoconically shaped section con~erglng ln down~tresm dlrection. The precombustion section 3 is a cyllndrical section confined by an upstream wall 31, a cylindrical wall 32 and a downstream confinlng w~ll 33.
Normally liquid hydrocarbon fQedstock can be introduced into the reactor along llne 6 which ~ equlpped with a dlscharge nozzle 7, which i~
arranged flush wlth the upstream wall 31 of the precombustlon sectlon 3. The hydrocarbon feed llne 6, as well a8 the nozzle 7, are surrounded by a pipe 8 through which a relatlvely small quantity of alr can be lntroduced lnto the reactor. Thls ~o-called Jac~et air is introduced in order to protect the noz~l~ und the hydrocarbon feet pipe 6.
A vortex of hot combustlon gases can be 8enerated withln the pre-combu~tion sectlon 3. Gas i~ introduced into the precombustion sectlon 3 for thiE purpose from gas discharge nozzles 34 and 35 ~see FIG. 2). Thls gas, which usually 18 nstural gas, is combusted with air whlch is introduced ~ ;
via ch~nnels 36 and 37, reepectively, whlch ~urround the gas discharge no~zle6 34 ~nd 35.

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The hydrocarbon feedstock axially introduced from nozzle 7 is con-tacted with the vortex of hot combustion gases and the reacti~n mixture is passed through the first reaction section 4 and, after an abrupt expansion, through the second reaction section 5. At the end of the reaction section 5, the reaction mixture is contacted with a quenching fluid, e.g., water or cold smole, injected in radial direction into the second reaction section 5 from lines 51 and 52, respectively. Thus quenched carbon black-containing smoke can be withdrawn from the reactor via a smoke withdrawal line 60.
A similar reactor as that shown in FIGS. 1 and 2 is shown in FIG. 3.
The cross section taken along line 2-2 of this reactor is the same as of the reactor in ~IG. 1, and reference is therefore also made for this reactor to FIG. 2. The main difference between the reactors shown in FIGS. 1 and 3 is the shape of the first reaction section and the location for the introduction of the hydrocarbon feed. The first reaction section 4 is an essentially cylin-drically-shaped section which is provided with a venturi-shaped choke 41. In addition, two different means for the introduction of hydrocarbon feedstock are provided for which can be used individually or in combination. The first means for introducing hydrocarbon feedstock into this reactor consist of radial spray nozzles 71 surrounded by cooling pipes 81 through which cooling "jacket" air can be injected. The second means for introducing hydrocarbon feedstock are located proximate to the abrupt expansion between the first reaction section 4 and the second reaction section 5. These hydrocarbon feed-stock injection means also consist of spray nozzles 72 for radial injection of hydrocarbon feed surrounded by cooling jacket 82 for injection of a small quantity of cooling or "jacket" air. Thus, as shown by these two embodiments of the reactors, the hydrocarbon feedstock can be injected into the reactors either upstream flush with the upstream wall or relatively far downstream in the first reaction section or even close to the abrupt diameter change into the second reaction section at the upstream end thereof. In this sense the term "first reaction section" is not to be understood in a technically limiting ", ~ .

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~en8e. Nith these exceptions, the second reactor shown ln FIG. 3 1~ the sa~e a8 that shown ln FIG. 1 and the same reference numerals have been used BO
that Q detailed explanation of the other elements of this reactor can be avolded.
A tgpical reactor in sccordance ~lth thi~ inventlon and in accordance wlth FIGS. 1 and 2 will have the following dimensions:
P (diameter of precombustion section 3): 10-1/4 lnches D (dl~meter of upstream end of fir~t reactlon sectlon 4) 3 inches d (dlameter of downstrenm end of first resctlon sectlon 4) 1.6 lnches S (di~meter of second reaction sectlon 5) 6 inches a (axial len~th of the precombu~tlon section 3) 4 inches b (axl81 length of the fir~t reactlon eection 4) 3-3/4 inche~ :

c ~axlal length of the eecond reactlon section 4) 52 lnches.
A typicsl reactor in accordance with FIGS. 2 and 3 wlll have the tlmen~lons shown in the following tabulation:
P (tiameter of precombustion section 3) 10-3l8 inches . D (diameter of upstream end of flrst r2action section 4) 3 inches . d ~diamcter of downstream ent of first . reactlon section 4) 3 lnches : S (diameter of 0econd reactlon sectlon 5) 6 inches a (axial length of the precombustioD ~ectlon 3) 4 inches b (axial length of the firs~ reactlon , ~ection 4) 12 inches ~:

c ~x~al length of the second reactlon sectio~ 4) 42 lnches 1 ~dlameter of the venturl throat) 1.6 inche~
;~ ~ 1 (~ngle between venturi and axls) 12 de8rees.
: The lnventlon wlll be yet more fully under~tood from t~e followlng ex~mple~.

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Example I
Three runs to produce a low tlnt re6idual carbon black in accordance with thl~ inventlon were carried out ln a reactor as described ln connection wlth FIGS. 1 and 2 and a~ ~pecified wlth respect to the dimen~lon~ thereof above. The feed o~l used ln all the runfi wa~ Ponca #7: BMCI - 120; ~id-boiling polnt (50%) ~ 755-F, average boiling point ~ 804F. The reactants introduced into the reactor, 8B well as the propertle~ of the carbon black produced sre ~hown in the following table:
TAsLE I
Run 1 Run 2Run 3 Tangentlsl air, SCF/hr. 11,000 7,5006,000 Tnngential natur~l gas, SCF/hr.732 500 400 Ratio A/G (volume ratlo)** 15/1 15/1 15/1 Z Excess air 50 50 SO
Axial air, SCFJhr. 0 22~ 175 Oil, pound~/hr. 101 69.6 47.3 Nozzle for oll 2 radial spray angle spray angle ~et~ 90 90 ~ozzle posltion flush* flu~h*flush*
Air/oil, SCF/pound 108.9 110.g130.5 Carbon black product N2SA, m2/gm 90 93 125 CTAB, m2/gm 88 88 104.5 24M4 DBP, cc/100 gm 87 lO0 103 Tln~ 88 91 96.5 T~nt re~ldual, ~R -12.8 -9.8 -9.1 * "Flush" means oll noz~le was at upstream face of the precombustlon chamber.
** Stoichio~etric for air/nstur~l gns i8 10/1.
Thc above data show that in a carbon black reactor as shown ln FIGS.
1 and 2, the low tlnt residual carbon black can be made. Furthermore, the data sh~wn abovc indicate thst the tint resIdual is partlcularly low for lcw ; alr-to-oll ratios.
Exa~ple II

In a reactor as ~hown in PIGS. 2 and 3, the partlcular dimensions of which h~ve been described in the above ~abulatlon, lo~ tint re~idual carbon ~ black, a~ well a~ h~gh tlnt re~dual carbon black were made. The only .1 ~
j _ g _ dlfference between the reactor used for th~s example and the reactor shown ln FIGS. 2 and 3 18 that the oll ln~ectlon nozzle and the oil inJectlon nozzle positlon were the ~a~e a~ that sbown ln connectlon wlth the reactor of FIGS. 1 and 2 for Runs 4 and 6. In Run 5 the oll nozzle was inserted 2 inches lnto precombustlon zone. Thug, the hydrocarbon feedstock wss in~ectet lnto the resctor essentlslly in axial direction at 8 locstion where the spray nozzle was srranged flush with the upstream confining wall of the precombus-tion soction and th~ nozzle was arrangea on the reactor axis. The ingredlents inJected into the reactor, their quantlties and ratlos, as well as the propertles of the carbon black msde ln sccordance wlth thls exa~ple, sro shown in the foll~wing Tsble II.
TABLE II
Run 4 Run 5 Run 6 Tan~entisl air, SCF/hr. 9,000 6,000 6,000 TangentiAl propane, SCF/hr. 255.6 213 170.4 ~atlo of alrlfuel (vol. rstio)** 36.2/1 28.9J1 36.1/1 % ~ces~ alr 44.8 ~5.6 44.4 Axlal alr, SCF/hr. 262.4 175 175 011, pounds/br. 70.6 45 56.3 20 Nozzle for oll spray sngle sprsy Qngle spray angle 90- 90- 90- ,,:

Noz~le posltlon~ flush 2" in pre- flush combuYtlon zone Air/oll, SCP/pound 131.2 137.2 109.7 ~ Csrbon black ~roduct:

I N2SA, m2/gm 130 119 99 CTAB, m2/gm 117 116 97 24M4 D~P, cc/100 g~ 98.5 97 96 30 Tlnt 107.1 128 99.7Tint resldual, TR -6.8 +12.1 -7.7 * "Flush" means the nozzle ie at upstream end of precombustlon chamber.
~ *~ Stoichiometrlc for air/propane is 25/1.

1:
The carbon black mste in accordance with thls example for Runs 4 and 6 showed a low tlnt residual, whereas the carbon blsck made ln accordance with Run 5 showed a very high tint residual.

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Example III
The three carbon black~ made ln accordsnce with Ex~mple I were compared to three commerclally avallable carbon black~ that were matched to the cRrbon blacks prepared ln accordance wlth Exsmple I as far B~ the structure and 6urface area were concerned but that dlffered e~entl~lly from these blscks as fsr as the elnt wa~ concerned. Therefore, in accordance wlt~
the formula of thls lnventlon, the t~nt resldual of the carbon blacks to be compared ws~ qulte dlfferent. ~he propertles of the carbon black~ whlch were compared are listed ln the followi~g Tsble III.

, Low Regular Low Regular Low Regular Bt. (IRB ~3) Hyst. (#1 Control) Hyst. t#~ Control) Run 1 Run 2 Run 3 CTAB, ~218 83 83 88 91 105 110 24M4, cc/100 g 87 88 100 100 103 100 Tlnt 88 100 91 105 97 llO
Tlnc reaidusl, TR -13 -2 -l0 -l2 -9 0 Ultra-flltration~* 3.50 2.35 3.18 2.17 3.10 2.20 * ~eterogeneity indox determlned by ultra~iltration 8~ descrlbed ln Rubber Chemi8try Tecb~ology, Vol. 48, No. 4, September-October, 1975, pp. 542-545.
The regular IRB #3 19 an lntustry reference black commercially avail-sbl in the lndu~try. The regular ~1 control carbon blsck 19 e cerbon black commercially svailable from the Phllllp~ Petroleum Company under the deslgna-tlon Philblac ~ N347. Simllarly, the regular ~7 contro~ carbon blsck i~ a carbon black commerclally svallable from the Philllps Petroleum Company, Bartlesville, Oklahoma, under the de~ignatlon N220.
The three carbon blacks llsted were incorporetcd lnto various rubber compcsielons of n~tural rubber snd of synthetlc rubber ln accordance with the following two reclpes:

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Reclpe 1 Recipe 2 SBRfBR Tread NR Tread SBR-1712~) 96.25 Ci~-4 1203(2) 30 NR (SMR-5 LBD~ (3) - 100 Carbon black t4) 75 50 Philrich #5 (5) 13.75 7 Zinc oxide 3 3 Stearic acld 2 2 BLE-25 t6) San~oflex AW (7) 1.5 1.5 Flexamine G (B) Sulfur 1.9 2.5 Santocure (9) 1.1 0.6 Cyuram MS (10) 0.15 ~1) A polybutedlene/~tyrene (76.5/23.5 we~ght ratlo) copolymer rubber, polymerized at 41-F and commercieslly avallable under the tratemark PhilprenèR SBR 1712 from Philllps Petroleum Compsny.
~2) A hlgh cis-poly,butadiene rubber commerc~ally availsble ~nder the trademark Cls-4R polybutadiene 1203, Phllllps Petroleum Company.
(3) Natural rubber, SMR-5LBD, is a natural rubber broken down to pre-eelected Mooney value of 54 raw Mooney at 212~.
(4) The varlous carbon blQcks llsted above were lncorporated lnto the rubber for comparative runs.
(5) A highly aromatic extender oil available from Phillips Petroleum Co., B~rtle~ville, Oklahoma.
~6) A high temperature rcaction product of diphenylamine and acetone, a commerclally availsble antioxldant.
(7) 6-ethoxy-1,2-dlhydro-2,2,4-trlmethylqulnoline, antloxidant and flex-crac~ing lnhibltor.
(8) Complex dlar~lamlne-ketone reaction product (65~) and N,N'-diphenyl-p-phenylenediamine (35X), an aneioxidant.
~g) N-cyclohexyl-2-benzothlazole sulfensmide, an accelerator.
~10) Tetramethylthiuram monosulflde, an accelerator.
The twelve rubber compositions 1D accordance wlth Reclpe 1 ant Recipe 2 glven above were then form~d into te~t speclmen~ and testea for vsrio~s rubber properties. The test results are shown in the following Table IV:

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TABLE rv Properties ln NR Tread_ (Recipe 2~
N33Q N347 __ N220 Low Regular LGW Re~uiar Low Regular H~t. (IRB #3) Hy8t. (tl Control) Hy~t. ~7 Control) Run 1 Run 2 ~un 3 ~T, F (Std. test)39 47 45 51 47 53 (Severe te~t) 53 83 90 104 112 121 Resilience, X 72 67 71 66 70 65 Modulug, p8i 1600 1550 1900 1880 1850 1750 Ten~lle, psl 3950 3980 3650 3980 4030 4280 Rlongatlon, X 580 590 510 550 560 610 212-P tear, lb/in.370 360 340 370 320 360 H~rdnas~ 58 58 60 63 61 61 Propertles ln SBR/BR Tread _~Recipe V
~T, F (orig.) 55 66 63 68 63 70 (aged~ 53 66 61 68 61 68 Re~ilience, %
(orlg. )65 54 60 56 5~ 52 ~ged) 67 57 64 59 64 59 MDdU~U8, p~l 1400 1300 1850 1800 1~40 1440 Tensile, p~l 2870 2940 3040 3030 3000 3130 Elongation, X 520 580 460 470 480 550 212~F tear, lb/in. 230 260 190 210 220- 259 ~Ardnees 55 58 61 62 58 60 ~T: This is the heat bulldup ln degrees F. determ~ned ln accord~nce with the stantard t~st ASTM D-623-67. In the severe test, the operation as dlsclosed ln ASTM D-623-67 i8 followed.
.
: %eellience: Determlnet ln acaordance with ASTM D-945-59.
Modulus: Determlned in accordance with AS~ D-412-68.
'~ Tenslle: Determlned ~ accordance with ASTM D-412-68.
.: ~longatlon: Deter~in~d ln accsrdance with ASTM D-412-68.
212-F tesr? Determi~ed ln Hccordance with ASTM D-624, using Die A.
Hard~ses Determined in accordance with ASTM D-676-59, All thæ dsta shown sbove lndicate that a very signi~icant i~prove-ment in the h~at buildup ~T ie ~chle~ed by the carbon black~ of thie lnve~- :
tlon ae compared to carbon blacks havlng slmilar propertles but hlgher tlnt resldu~l TR~ An lmprovement ln the he~t bulldup of 6 ~o 8 degrees 18 very lmportant and the r¢~ults o the ~evere test further show an even hlgher l~prov~ms~t in the heat buildup or temperature change ln a rubber co~position incorporatlng the carbon black of thl6 inventlon as compared to a rubber compo~ltlon ~ncorporAti~g a 61ml1ar carbon black with a hlgher tint resldual.

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Example IV
The carbon blacks made in accordance wlth Example II, ~8 well as snother carbon black having propertles closely slmilar to the carbon black Run 6, but differing ln the tlnt resldual, were evaluated ln rubber tests.
Ihese carbon black~ were lncorporated lnto rubber compositions as shown above in connectlon wlth Recipe No. l. The properties of the carbon blacks, as well as the rubber test results are shown in the followlng Table V: -TABLE V

Run 4 Run 5 ~un 6 Run 7 CTAB, m /gm 114 118 99 105 24M4, cc/lO0 g lO0 97 97 93 ~int 106 124 99 117 Tint resldual, T~ -6 8 -7 S
.I. (Ultraflltration)2.65 1.96 2.87 1.75 Cut growth, in. (1) 0,068 0.124 0.033 0.108 ~I T, F (~TD) 64 74 62 66 Resllience, ~ 59 53 60 57 Tresdwesr (2) 111 110 99 103 (1) Cut growth: Determined in stAndard tlre tests.
~2) ~r-adwear: Determlned ln standart tlre tests.
The sbove-reported dats agsin show that the heat bulldup or hy~teresi~ of a rubber composltion incorporatlng a low tint residual carbon blsck 1~ conslterably lmproved 8~ compared to a hlgh tlnt resldual csrbon blsck. In ~dditlon, however, the rubber tests show that the treadwear remains unchanged for the csrbon blacks compared.
~ EXAMPLE V
¦~ In the following three reclpes, typ~cal composltions for passenger car tlre tresd, pa~senger csr tire csrcasses and truck tire csrcssoes sre glven:

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Passenger Car Tire Tread ComPonent Pounds Phllprene~ SBR 1712 (2) 96.25 Cls-4B Polybutadiene 1203 (3) 30 Carbon blsck 75 Ph~lric~R 5 (6) 13.75 Zinc oxide 3 Stearlc acld 2 BLE-25 (8) Santoflex AW (9) 1.5 Santocure (10) 1.1 Cyursm MS (11) 0.15 Sulfur 1.9 Pas~enRer Car Tlre Carca~ses Nstural rubber 40 Phllpren~ SBR 1708 tl) 41.25 Cls-4~ Polybutadiene 1203 (3) 30 Carbon black 50 Roeln oll 3 Zlnc oxide 4 Se~arlc acid 2 Agerlte Re~ln D (4) 1.5 Amax ~1 (5) O.8 Dlphenylguanldine ~.1 Sulfur 2.5 $ruck Tire Carcasses Naturgl rubber 80 Clo-4.~.~Polybutadlene 1203 (3) 20 Carbon ~Rack Phllr~c~-15 (6) 7 Zinc oxide 5 Stearic acit 3 :
Sulfur 1.9;
NOBS Special t7) 0.9 (1) Colt, oll-e~tended non-staining SBR rubber: 100 parts by welght low ash, low water absorptlon llght-colored butadlene-styrene (75-25 weight ratlo) copolymer, emulslon-polymerlzed at 41F
u8ing fatty acid soap and 37-1/2 parts by welght naphthenlc proce~slng oll. Co~merclally avallable from Philllps Petroleum Company, Bartlesvllle, Oklahoma.
t2) A butadiene/styrene copolymer rubber (76.5/23.5.butadlene/
styrene weight rstio) commerclally available from Phillips Petroleu~ Company.
(3) ~ hlgh cis-polybutatlene rubber commerclal b avsilable from Philllps Petroleum Compsny.
(4) An antioxldant, 1,2-dihydro-~2,4-trimethylquinol$ne.
(S) N-o~ydiethylene benzothiazole-2-sulfenam$de and benzothia-zyldlsulfide, a delayed-action primary accelerator.
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~6) A highly aromatic extender oll cnmmerclally available from Phillip~ Petroleum Company.
(7) N-oxydlethylene-2-benzothla~yl sulfenamide.

~8) High-temperature re~ctlon product of diphenylamine and acetone, an antioxldant.
(9) 6-Ethoxy-1,2-dlhydro-2,2,4-trlmethylqulnoline, an antioxldant ~nd flex-cracklng lnhlbltor.
(10) An accelerator, N-cyclohexyl-2-benzothlazole sulfennmlde.
~11) An ~ccelerator, tetramethylthlur~ monosulflde.
The tlre rubber composltions shown above lncorpor~tlng the carbon black of the preeent lnvention wlll show reduced hysteresl~ or heat buildup, 88 hB8 been shown in the previous exQmples. This feature advantageously wlll decressQ the rlsk o~ tlre blowouts ant the tires catching fire.
RsAson~ble varlatlons and motiflcatlons wlll become apparent to thoee skillet ln the art from a readlng of this disclosure without departing from he aplrlt Dnd copc ehereof.

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Claims (5)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A composition comprising a carbon black having a tint residual of less than about -6 and a tint in the range of about 70 to 100 in combi-nation with a rubber selected from the group consisting of natural rubber, synthetic rubber, and mixtures thereof.

2. A composition as in claim 1 wherein the carbon black has a 24M4 DBP structure of about 67 to 111 cubic centimeters/gram, a surface area of about 73 to 140 square meters/gram, and an (N2SA-CTAB) value about equal to or less than 23 square meters per gram.

3. A composition as in claim 2 wherein the carbon black has a tint residual of between about -6 and about -20.

4. A composition as in claim 3 containing about 10 to about 200 parts by weight of the carbon black per each 100 parts by weight of the rubber.

5. A composition as in claim 4 containing about 20 to 80 parts by weight of the carbon black per each 100 parts by weight of the rubber.