CA1229940A - Rubber compositions containing aromatic furazan oxides - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE:

Uncured rubber compositions containing fused aromatic furazan oxides exhibit improved processability and reduced viscosity. Useful furazan oxides have both carbons of the furazan ring as part of a fused aromatic ring and include benzofurazan oxide and its methyl and methoxy analogs. Improvements in processability, green strength and liquification of natural rubber can be achieved through use of these furazan oxides in uncured rubber compositions.
Filled rubber vulcanizates containing aromatic furazan oxides exhibit many improved properties such as increased filler-rubber interaction and decreased hysteresis. Useful furazan oxides have both carbons of the furazan ring as part of a fused aromatic ring.
Typical examples are benzofurazan oxide and its methyl and methoxy analogs. Tires made from the inventive vulcanizates show lower running termperatures and improved rolling resistance.

Description

D~81- AHAB

RUBBER COMPOSITIONS
CONTAINING AROMATIC FORESEEN OXIDES

This invention relates to uncured rubber compositions and willed volcanists made therefrom. More particularly, it relates to such compositions exhibiting improved properties and containing aromatic foreseen oxides. It also relates to methods of improving the process ability, green strength and viscosity properties of uncured rubber compositions and articles made from the volcanists, such as tires, and methods of improving the rolling resistance and running temperatures of such tires.

BACKGROUND Of THE INVENTION.
It is well-known that, with very few exceptions, rubber compositions are combined with various other materials before being cured and/or put into use. Some of these added materials improve the properties of the end product in service while others improve processing proper-ties of the uncured compositions. In some instances, both effects may be achieved. It is also known that the various chemicals, pigments and other materials so used, ; both organic and inorganic, can interact in various ways to produce desirable or deleterious effects. For further discussions of rusher processing and materials used therein, see, for example, Encyclopedia of Polymer Science and Technology published by John Wiley and Sons, New :

2 --York (19703, particularly volume 12, page 280 and The Vanderbilt Rubber Handbook, R. T. Vanderbilt Company, Norwalk, Connecticut, 06855 (1968), particularly Sections 6, 7, 8, 9 and 11.
Benzofurazan oxides, and their analogs and isomers are known compounds, and many descriptions of them and procedures for their preparation have appeared. See, for example, Kaufman, et at., "Chemical Reviews," volume 9, page 429 end following ~19593 and Mallory, et at., "Organic Synthesis" collective volume IV, pages 74 and 75, John Wiley and Sons, New York (1963~. The following US.
Patents also describe procedures for preparing foreseen oxides of various types: US. Patent 4,185,018 to Fax;
US. Patent 3,528,098 to Skew; and US. Patent 2,424,199 to Ton Host. In considering previous descriptions of foreseen oxides and related compounds, it should be noted that nomenclature used for these compounds has not been consistent, in part due to uncertainty as to their structures and predominant isometric form. For example, they have been described as foreseen oxides, as ortho donators benzenes or do (nitrite oxides). At other points, they have been referred to as isobenzofuroxans, benzofuroxans, benzofurazan-N-oxides and benzofurazan oxides. It is believed that the latter term is the modern and preferred nomenclature, and it shall be used in this specification and the appended claims.
Studies of foreseen oxides and related compounds in rubber have been reported. For example, Renoir and Floury state in Industrial and Engineering Chemistry, 30 volume 38, page 500 et sea, that ortho donators Bunsen is inactive in bottle rubber as a vulcanizing agent. In contrast, the pane isomer is said to be very active by Renoir and Floury. US. Patent 3,931,121 to Davis, et at., describes the curing of elastomeric polymers with posy 35 (chlorinators compounds. US. Patent 3,931,106 to I

Crosby, et at., describes the use of dinitrile oxides, which can be generated in situ from fierceness, in rubber cross-linking. In -this regard, it should be noted that -the aromatic foreseen oxides of this invention cannot isomers to do (nitrite oxides) because -the bond between the adjacent carbon atoms is part of an aromatic ring. US. Patent 2,974,120 to Miller describes the use of non aromatic furoxans as antioxidant and antidegradants in rubber US. Patent 2,905,582 to Coleman, et at., describes the use of nutrias compounds, including donators compounds wherein the nutrias groups are on nonadjacent carbons in a method for bonding polyurethane resin to rubber bodies. Merritt has described the use of N, ~-dinitroso-N-methyl aniline as an active chemical promoter for carbon black reinforcement of SIR, NO
and SIR. See Rubber Chemistry and Technology, volume 49, page 119 and following (1976). Tanaka, et at., have reported studies of nutrias Bunyan in rubber where chain cleavage was observed in Cage Kagaku Zasshi 74 (8), pages 1701-6(1971).
SUMMARY OF TIE INVENTION.
The present invention proposes a method of improving hysteresis properties in a filled volcanist containing at least one rubber having an unsaturated carbon chain and at least one filter selected amongst carbon black and silica, which comprises including in the volcanist a minor, filler-interaction-promGting amount of aromatic foreseen oxide of the partial formula:
I
f N
I N

wherein the depicted carbon atoms are part of a single aromatic ring.
The invention also proposes a tire exhibiting improved hysteresis properties, which has at least one I

I

.. .

portion thereof, preferably the thread portion, made of an improved, filled volcanist as obtained with the above mentioned method.
The present invention further proposes a method of improving the process ability and/or reducing viscosity of uncured rubber compositions containing at least one rubber having unsaturated carbon backbone chains which comprise including in the composition an effective amount of at least one aromatic foreseen oxide of the partial formula of - N
C N /

wherein the depicted carbon atoms are part of a single aromatic ring.
The present invention further proposes a method of reducing the running temperature of a tire which come proses making at least a portion of the tire from a filledvulcanizate comprising at least one rubber having an unswept-rated carbon chain, a filler and a minor, running temperature reducing amount of at least one aromatic foreseen oxide of the partial formula:
- O
f N
CON

wherein the depicted carbon atoms are part of a single aromatic ring.

DETAILED DESCRIPTION OF THE INVENTION
The rubber compositions of the first aspect of I
- pa -this invention are not cured, that is, they are uncured and not vulcanized. In some instances, they contain curing agents (systems) and thus are capable of being cured. In other words, they are vulcanizable~ In other instances, the compositions of this invention do not contain curing agents, either because they are _ _ _ /

intermediate compositions to which a curing system will be, but jot yet have been, added or because they are to be put in use without thy addition of curing agents in such applications as sealants, caulks, adhesives and the like.
In any event, the invention includes uncured rubber compositions containing aromatic foreseen oxides whether or not they contain, in addition, curing agents, and whether or not they are intermediates to which curing agents are to be added.
Said curing agents, when present, are of the conventional type such as sulfur-or perGxide-based curing systems and the like. They are used in conventional amounts and incorporated in the uncured compositions of this invention by known techniques and procedures.
Fillers (pigments) may be, and often are present as is known to those skilled in the art. Typical fillers include carbon black in its various forms, glass, silica, talc and similar finely divided mineral materials.
The rubbers used in the uncured compositions of this invention have unsaturated carbon chains. That is, their polymer backbones contain a significant amount of unsaturation, in contrast to the pendant or vinyl saturation as found in some other types of rubbers.
Typically, the chains of such unsaturated rubbers have at least about 20% of their carbon to carbon bonds as unsaturated bonds. Characterization of rubber as having unsaturated carbon chains it well-known in the art as shown by ANSI~ASTM Standard D AYE where unsaturated-chain rubbers are referred to as R rubbers.
Class R rubbers include natural rubber and various synthetic rubbers derived at least partly from dolphins.

rye following is a nonexclusive list of R class rubbers Welch can ye used in the compositions of the present invention (the abbreviations AIR, eke.
are assigned to the rubbers for easy reference latter in the specification):
AIR- Acrylate~butadiene BIER- Bromo-isobutene~isoprene BR~-Butadiene CIIR-~Chloro~iso~utene-isoprene OR -Chloroprene I~R-~Isobutene-isoprene IR--Isoprene, Cynthia to NOR ~-Nitrile-butadiene NCR--Nitrile-chloroprene NIR~-Nitrile~isoprene NR--Natural rubber PBR~-Pyridine-butadiene PSBR--Pyridine-styrene-butadiene SBR--Styrene-butadiene SCR--Styrene-chloroprene SIR--Styrene-isoprene rubbers.
I Compositions where the rubber is NO, IRK BRA
: BRIE, OR, SHARI, NOR or mixtures ox two or more of these are kypîcally used. Many compositions are made wherein the rubber is NO, SIR or a mixture containing at least about 50 percent of one of these. Compositions containing only NO as the rubber portion are often used. In the context of this invention, NO includes both heave and Gaul rubber as well as mixtures thereof.
: The compositions of the present aspect of this invention can also contain materials used in conventional rubber formulation such as antioxidant, accelerators, retarders, promoters and the like in addition to the curing systems and fillers noted above. It should be noted, however, that it is sometimes desirable to choose such materials with care since they may interact with the event at foreign oxides.

I
I

The rubbers of another aspect of this invention, that relating to volcanists (i.e., cured stocks) are essentially the same as those described above.
The volcanists of the present invention also contain fillers of the conventional type such as carbon black in its many forms, clays, talc, pyrophyllite, silica and other inorganic, finely divided materials. In addition, they contain conventional curing systems and agents, such as sulfur, antioxidant, accelerators, lo retarders, coupling agents, promoters and the like. It should be noted, however, that it is sometimes desirable to take care in choosing such materials since they may interact with the foreseen oxides.
The foreseen oxides used in both the vulcanizable and w lcanized (cured) compositions of this invention are fused aromatic, that is, they have an aromatic ring fused to the N-oxidized heterocyclic foreseen ring. They are of the partial formula C - N

C N

wherein the depicted carbon atoms are part of a fused, single aromatic ring. This aromatic ring can be carbocyclic such as a Bunsen ring or it may be heterocyclic, such as a pardon ring. It can be the only additional ring in the foreseen compound, or it can be part of a linked or fused ring system. It is only necessary that both depicted carbon atoms be part of the same aromatic ring.

Examples of the foreseen oxides useful in the vulcanizable and cured compositions of this invention are those that can be represented by the formulae O O
ON N

N N

Y No 15 and I I 0 N

wherein none, one or any two of the ring positions can be substituted with lower hydrocarbyl, halogen, hydroxyl, lower hydrocarbyl ox, lower hydrocarbyl Ohio, lower hydrocarbyl carbonyl, carbonyl lower hydrocarbyl ox, vitro, amino or amine groups and Y is a linking atom or group. In this context, lower hydrocarbyl refers to groups of carbon and hydrogen having eight or less carbon atoms such as methyl, ethyl, bottle, ponytail, hotly, octal (all isomers). Linking atoms or groups include ether, trio ether, sulfoxide, cellophane, amine, ethylene and the like (including simple covalent bonds such as found in biphenyl) and the other linking groups shown in US.

_ 9 _ Patent 3,528,098. Hydr~byl ox, h~dx~ar~yl this and muted hy~x~arbyl oxa~thia stituents are also pus to worth hydrocarbyl groups are typically lower alkaline moieties. Such are often made from glycol~, deathless, epoxies and epi~ulfides. Often the foreseen oxide is a benæofurazan oxide of the formula - - I o JO

wherein none, one or any two of ring positions can be substituted with lower hydrocarbyl, halogen, low hydrocarbyl ox, lower hydrocarbyl trio, lower hydrocarbyl carbonyl, carbonyl lower hydrocarbyl ox, vitro, amine or amino groups. Typically, the foreseen oxide is benzofurazan oxide or the methyl or methoxy analog thereof.
Methods for preparing, purifying and handling these compounds are known to the art as is shown by the references cited hereinabove. It should be noted what some of these foreign oxides, particular those containing relatively large amounts of nitrogen and oxygen, such as bannister (foreseen oxide) and Dow (vitro) benzofurazan oxide, are prone to rapid decomposition to the point of explosions; all may be physiologically active to varying degrees. Therefore, care in their handling and use should be exercised.

joy ' The vulcanizable compositions of the present invention can be prepared by conventional techniques using various types of mills, blenders and mixers known to the art. The cured compositions can be made by the same techniques followed by curing. Usually the amount of foreseen oxide used is a property-improving amount, such as an amount which will improve the process ability of the composition and, in certain instances, its green strength and viscosity properties. Process ability properties are those related to the ease and efficiency of mixing, mastication and handling of a rubber composition in its unvulcanized, that is, uncured state. They include Viscosity and often the speed and efficiency with which various other components are dispersed in the rubber.
Similar amounts are used in the cured composition to improve such volcanist properties as filler interaction, modulus, resiliency, hysteresis, rolling resistance, running temperature and the like. Typically, this property-improving amount will range from about 0.1 to 10 parts per 100 parts (by weight) rubber (fry Often the foreseen oxide will be used in an amount ranging from 0.5-5 phi. The temperatures used in formulating the rubber compositions of this invention range from ambient to those normally used in the art, such as 75 degrees to 175 degrees or ambient, say 20, to those conventionally used such as 150 to 200. In its broader aspects, the formulations can be made from about 20 degrees to 220 degrees. Although in many instances, narrower temperature ranges such as about 50 degrees to 190 degrees are employed. As noted hereinabove fillers, promoters, curing agents and other conventional rubber additives are also often included in these procured mixtures in conventional amounts.
!

I

The volcanists of this invention are prepared by curing the foreseen oxide containing compositions under conditions of temperature and time customarily used in the art, and the invention is not significantly dependent on such curing variables. Typically the rubber and filler (or pigment are first mixed and then the mixture treated with foreign oxide before curing. Other sequences can also by used but it is essential to have the rubber, filler (pigment and foreseen oxide intimately combined before vulcanization.
Among the desirable and beneficial properties exhibited by the compositions of the present invention are improved process ability, enhanced green strength and in some instances reduced viscosity. Compositions containing substantial amounts (greater than 50 percent) of NO, IT or OR show improved process ability and enhanced green strength. Improved process ability of uncured rubber formulations is often desirable because it permits savings in energy and time while compounding and subsequent processing of Thurber by techniques such as calendering, milling, remitting, extrusion and the like.
Such savings are important in the current period of shortages and rising costs. In general process ability is an inclusive term used also to describe the decreased viscosity and/or high green strength such as found in the compositions of this invention. Heretofore, it has often been found that decreasing viscosity of an uncured composition also results in decreased green strength.
Similarly, increasing green strength has been found to increase viscosity. It is a particularly desirable feature of the compositions of the present invention that viscosity reductions are achieved in combination with green strength increases.

In general, NO, IT and OR containing compositions show viscosity reductions of about I Mooney units for about 0.5-1.5 phi foreseen oxide with accompanying increases in green strength of about 20-100 psi. Similar levels of foreseen oxide in synthetic rubbers such as, for example, SIR show Mooney viscosity increases of about 10 units while when peak green strength is increased about 5-50 psi. With higher levels of foreseen oxides (e.g. 2-5 phi), the extreme in viscosity reduction can be reached with liquefaction of NO and IRK Such liquid rubbers are useful in sealants and as processing aids where they are combined with other types of rubber to aid in plasticizing rubber. Liquid rubbers, also known as depolymerized rubber ~DPR), are well-known in the art and need not be further described here. It is sometimes found that the viscosity reductions observed in the compositions of the present invention are accentuated by the inclusion of antioxidant and materials such as carbon black and silica which are believed to interact and trap polymer free radials prior to their cross-linking. Thus maximum viscosity reductions can usually be achieved by adjusting the concentrations of the foreseen oxide and the antioxidant or radial trapping materials (fillers) in a given rubber composition.

EXAMPLES
The following, non limiting examples exemplify the practice of the invention and include the best mode presently known. In these examples, as elsewhere in the specification and claims, all parts and percentages are by weight (pow), unless specified otherwise, and temperatures are in degrees centigrade. Conventional rubber compounding materials, conditions, temperatures, procedures and evaluation techniques are used unless noted to the contrary.

MASTER BATCH PREPARATION
In the following examples, an internal mixer, such a a Bra bender or small it Danbury mixer, was used. The usual technique was to add various materials, often in portions, to the mixer and continue mixing for the indicated time period. Further additions followed by mixing are when made lo thy master batches thus prepared.
the standard technique was according to the following schedule:

TIME, ADD TO MIXER

O Polymer, 100 parts .5 half charge filler plus foreseen oxide 1.5 Balance filler plus zinc oxide, Starkey acid

3.0 Processing oil 156.0 Drop mixed composition at 160-170F

The uncured master batch was then immediately banded and sheeted on a small twin roll mill set at 60 gauge. Mooney viscosities were measured using the large rotor in a four minute cycle at 100 degrees. This procedure was used to make master batches from NO (Hove) and SIR (trade name Duradene* available from The Firestone Tire & Rubber Company, Akron, Ohio, USA).

EXAMPLE ONE
A series of typical tire belt skim formulations were prepared using 100 percent natural rubber containing zinc oxide (5 phi), Turk acid (2 phi), carbon black (40 parts) and varying amounts and types of foreseen oxides.
Each was mixed 5 minutes and dropped at 143. The additives used and results were as follows * Trade mark Jo I

Additive _ Mooney Green Strength, psi Stock Type Amount Vise unit puked Eon Control 41 25135 810 IA BF0 (a) 1 I 20340 670 IT MBFO(b) 1 24 25300 650 Compare 50n Petunia 44(C) l 26 25 80 735 a - benzofurazan oxide - 6 - methyl benzofurazan oxide c - Petunia 44, a commercial peptize sold by American Cyanamid Co., d - break same as peak e - percent elongation - at 50% elongation As can be seen from the proceeding Table, stocks IA and IBM both of which contained foreseen oxides exhibited decreased Mooney viscosities and, at the same time, increased green strengths.

EXAMPLE TWO
TV A SBR-based passenger tire tread stock composition was prepared containing about 60 phi carbon black and conventional amounts of zinc oxide Turk oxide and a waxy antioxidant. A similar formulation containing in addition 1.0 phi benzofurazan oxide was prepared under comparable conditions. The Mooney viscosity * Trade mark I

of the control was 60.0 and of the foreseen oxide containing composition, 68.9. The Green stress-strain properties of the two compositions were as follows:

Control control Plus BOO

initial 33 50 Peak 43 84 Break 27 84 Elongation, % 545 57 EXAMPLE THREE
A NO composition was prepared containing about 40 parts ISAF black, about 20 parts Hazel silica and convent tonal amounts of zinc oxide, antioxidant, softener, resin, sulfonamide accelerator, sulfur and retarder. An essentially identical composition was prepared containing, in addition, 1 phi benzofurazan oxide. The control had a Mooney viscosity of 64 . 4 and the foreseen oxide formula-lion, a viscosity of 49 Ø Thus, 1.0 part foreseen oxide causes a 15 unit decrease in viscosity under identical ; mixing conditions.

EXAMPLE FOUR
Two typical truck tire tread compositions were prepared from grade B NO containing silica filler (about 80 phi Hazel silica. Conventional amounts of Solon coupling agent, plasticizer, antioxidant, processing oil, sulfur, accelerator, retarder, resin and activator were also included. The composition without foreseen oxide was hard to mix in a 1.3 kg Danbury and when dropped was very dry, stiff and had the appearance of sawdust. A second compound of the tame formula containing, in addition, 1 phi benzofurazan oxide was ready to drop after only six minutes of mixing but was given the same 12 minute mix as the control. It dropped smoothly from the Danbury and was jot stiff.

EXAMPLE FIVE
A series of rubber compounds based on IT was prepared. The compounds were free of filler and curing agents; they contained varying amounts of methyl benzofurazan oxide, ranting from O to 2.5 phi and, in some instances, 2.0 phi commercial antioxidant (Santoflex*13).
Each was mixed 6 minutes at 150F and then the Mooney viscosity determined. The results are shown in Table PA.
As can be seen, with the compounds containing no anti-oxidant, viscosity increases up to 1.5 phi foreseen oxide and then falls sharply. This increase is believed to be due to cross-linking reactions which compete with chain sets ion. At high level of foreseen oxide session overtakes cross-linking and viscosity reduction results.
20 Other observations revealed that in the presence of carbon black viscosity increases do not occur. Rather, only a steady decrease in viscosity with increasing foreseen oxide is observed.
In the stocks containing both foreseen oxide and antioxidant, a similar steady decrease in viscosity was observed. It is believed that the antioxidant impedes cross linking and the decrease due to chain session is evident.

* Trade mark ~^~

TABLE PA

Additive, phi Mooney Vise., 100 MBFOSANTOELEX aye 50.5 0 46 1.0 o 53 1.5 0 55 2.5 0 19 2.0 70 101.02.0 40 2.0 2.0 19 (a) _ A commercial antioxidant available from the Monsanto Chemical Co. of St. Louis, Missouri, USA.

EXAMPLE I A similar series of rubber compounds based on SIR was prepared containing methyl benzofura7an oxide and, in some instances, Santoflex 13. In the absence of the latter, a steady increase in viscosity is observed.
When antioxidant is also present, a steady decrease in viscosity resulted as shown by the data in Table 5B.

Additive, or Mooney Vise., 100 M _SANTOFLEX 13 0.5 0 54 251.0 0 59 1.5 0 65 2.5 0 67 O 2.0 45 1.0 owe 30 302.02.0 23 Master batches prepared according to the procedure described above were immediately banded and sheeted on a small twin roll mill for two minutes set at 60 gauge. Mooney viscosities were measured using the large rotor, and a four minute cycle at 212F. Master batches prepared essentially according to this schedule were combined with conventional ~lastomer curing systems in typical amounts and cured for 15, 23 and 30 minutes at 300 F to provide test specimens. Typical conventional curing systems include sulfur-, peroxide-, urethane-, and benzoquinone dioxide systems.

EXAMPLE SIX
A series of volcanists was prepared using a conventional carbon black containing formulation and sulfur based curing system. The volcanists also contained about 20 parts Hazel silica and conventional amounts of zinc oxide, antioxidant, softener, resin, sulfonamide accelerator, sulfur and retarder. The first (the control) contained no promoter, the second 0.6 phi Nitrol*(Monsanto Chum Co.) and the third 1.0 phi buoyancy-foreseen oxide. Neutral is a known promoter and was used at its recommended level. Evaluation data for each vulcan-Nate are shown in Table I. Clearly the benzofurazanoxide containing volcanist is superior in most properties and exhibits no significant deficiencies in any property.

EXAMPLE SEVEN
Typical truck tire tread volcanists were prepared from grade B natural rubber filled with silica (about 80 parts phi Hoyle) and containing conventional amounts of Solon coupling agent, plasticizer, antioxi-dents, processing oil, sulfur, accelerator retarder, resin * Trade mark I,....

and activator. It was noted that the conventional composition was hard to mix in a 1.3 Kg Danbury and when dropped was very dry and stiff with the appearance of sawdust. The same mixture containing, in addition, 1 phi benæofurazan oxide was ready to drop after only six minutes but was given the same 12 minute mix as the control. It dropped smoothly from thy, Danbury and did not exhibit the stiffness and appearance of the control. The two compounds were cured in the same manner and evaluated in a number of standard tests. The results of these evaluations are shown in Table II. Clearly the volcanist containing 1 phi benzofurazan showed improved (that is, lower) running temperature and increased rebound.
Other properties are not significantly diminished by the presence of the foreseen oxide.

EXAMPLE EIGHT
A series of typical tread stocks was prepared from synthetic rubber according to a typical tread stock recipe calling for about 60 parts carbon black. The control contained no additive and Examples PA and 3B
contained one phi of methoxy benzofurazan oxide and buoyancy-foreseen oxide, respectively. Each stock was cured in the usual manner and the volcanist specimens evaluated in a number of standard tests. As can be seen from the data in Table III, the stocks containing the benzofurazan oxides showed superior properties.

TABLE I
Buoyancy-None foreseen Promoter~Feature(Control~ Neutral Oxide Monsanto emoter 300F 8.7 TC(9Q) 21.3 21.3 19.8 Min. Torque 9.8 10.8 7.4 Torque at 90% Cure 38.0 38.1 37.1 Max. Torque 41.1 41.1 40.4 CRY 7.2 7.4 9.0 Shore "A" hardness 73~F 72 71 71 Ring Tear at 212F

Ring Tensile at ambient temp.
300% Modulus 1914 1947 2410 Tensile 2573 2479 2868 Elongation 391 368 352 Aged Ring Tensile 2 days at 212F 1848 200% Modulus 1614 1628 Tensile 2211 2307 2542 Elongation 275 280 270 Rebound 73F 39.5 42.0 51.0 _ Firestone Fle~ometer 5501bs, .4" throw 22 7 22 7 % Deflection 26 B1QW_OUt, min. 9 9 13 Firestone Flexometer 2501bs, .3" throw 8 10 7 % Deflection 8 Running Temp., OF 340 317 268 TABLE II

1 Phi, Buoyancy-ControlFurazan Oxide Shore "A" Hardness 73F 68 6g Ring Stress-Strain 23' cure - 300% Mod. 1619 1178 Tensile 2546 2072 Elongation 449 463 MATS 7,~ Deflection, lullaby, 10 HO
I' 14Q0 1130 K" 302.8 247.5 Tan delta .216 .219 Monsanto Remoter at 300F
TS~2) 10.3 8.7 TC(90) 15.3 16.1 Min. Tory 15.5 12.8 Torque at 90% Cure 51.1 40.8 Max. Torque 55.0 43.9 CRY 20.0 13.5 I Rebound Rink Tear at 212F

Firestone Flex 2501bs, .3" throw % Deflection 7.3 14.0 Running Temp., OF 385 295 TABLE III
Methoxy None Benzofurazan Benzofurazan Promoter/Feature (Control _ Oxide Oxide Monsanto Remoter 300~F
TO 14.3 16.3 16.4 TC(90) 23.3 22.3 23.2 Min. Torque 11.3 12.0 9.6 Torque at 90% Cure 39.5 39.3 38.4 Max. Torque 42.6 42.3 41.6 CRY 11.1 16~7 14.7 Shore Lowe Hardness 73~ 60 57 58 Ring Tear at 212F 147 137 147 Ring Tensile at ambient them 300% Modulus (cured 30' 1594 2065 1806 Tensile at 300F) 2375 2154 2172 Elongation 399 311 345 Rebound: 73F 43 51.0 49.0 Rebound: 212F 63 69 68 Firestone Flexometer 2501bs, .3" throw 16 15.3 Running Temp., OF 254 235 245 Resistivity, 30' at 300 F 0.4 -1.2 CUB. Dispersion, 93 91 95 Carbon Bound Rubber, % 19.6 36.0 28.2 Rolling Resistance, % par -5 -5 TABLE III (Continued) Methoxy NoneBen~.ofurazan Benzofurazan Promoter/Featur~ (Control) Oxide Oxide MATS 7% Deflection, lolls, 10 Fly K' (ambient Temp.) 95.0 900 K" (Ambient Temp.) 197 144 156 Tan delta (Ambient Tamp.) .207 .160 .168 K' delta (212F) 800 750 770 K" delta ~212F~ 137 99 112 Tan delta (212F) .171 .131 .146 I

While the invention has been described and exemplified herein by reference, specific materials, machinery, techniques, procedures and examples, it is understood that it is not restricted to any of these numerous variations, combinations, and permutations can be made within the scope of the invention as is clear to those skilled in the art.

, .

Claims (13)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of improving hysteresis properties in a filled vulcanizate containing at least one rubber having an unsaturated carbon chain and at least one filler selected amongst carbon black and silica, which comprises including in the vulcanizate a minor, filler-interaction-promoting amount of aromatic furazan oxide of the partial formula:

wherein the depicted carbon atoms are part of a single aromatic ring.

2. The method of claim 1, wherein the rubber is MR, IR, BR, SBR, CR, CIIR, NIR or a mixture of two or more of these.

3. The method of claim 1, wherein the rubber is NR, SBR or a mixture containing at least about 50 percent NR, and the filler is carbon black.

4. The method of claim 1, 2 or 3,wherein the furazan oxide is of the formula:

wherein none, one or any two of positions 4, 5, 6 or 7 can be substituted with lower hydrocarbyl, halogen, lower hydrocarbyl oxy, lower hydrocarbyl thio, lower hydrocarbyl carbonyl, carbonyl hydrocarbyl oxy, nitro, amino or amine groups.

5. The method of claim 1, 2 or 3, wherein the furazan oxide is benzofurazan oxide or a methyl or methoxy analog thereof.

6. The method of claim 1, 2 or 3, wherein the amount of aromatic furazan oxide in the vulcanizate ranges from about 0.1 to about 10 phr.

7. A tire exhibiting improved hysteresis proper-ties, said tire having at least a portion thereof made of an improved, filled vulcanizate as obtained with the method of claim 1.

8. A tire as claimed in claim 6, wherein said improved filled vulcanizate comprises NR or a mixture con-taining at least 50 percent NR.

9. A method of improving the hysteresis proper-ties and thereby reducing the rolling resistance of a tire which comprises making the tread portion of the tire from an improved, filled vulcanizate as obtained with the method of claim 1 or 2.

10. A method of reducing the running temperature of a tire which comprises making at least a portion of the tire from a filled vulcanizate comprising at least one rubber having an unsaturated carbon chain, a filler and a minor running temperature reducing amount of at least one aromatic furazan oxide of the partial formula:

wherein the depicted carbon atoms are part of a single aromatic ring.

11. A method of improving the processability and/
or reducing the vicosity of uncured rubber compositions containing at least one rubber having unsaturated carbon backbone chains, which method comprises including in the composition an effective amount of at least one aromatic furazan oxide of the partial formula:

wherein the depicted carbon atoms are part of a single aromatic ring.

12. The method of claim 11, wherein the furazan oxide is of the formula:

wherein none, one or any two of positions 4, 5, 6 or 7 can be substituted with lower hydrocarbyl, halogen, lower hydrocarbyl oxy, lower hydrocarbyl thio, lower hydrocarbyl carbonyl, carbonyl hydrocarbyl oxy, nitro, amino or amine groups.

13. The method of claim 11, wherein the furazan oxide is benzofurazan oxide or a methyl or methoxy analog thereof.