DESC:FIELD OF THE INVENTION
The present invention relates to the field of tread rubber composition for green tyre. More particularly, it relates to a high-performance motorcycle tire tread composition and its method of preparation.

BACKGROUND OF THE INVENTION
A tyre tread must meet, in a known way, a large number of often conflicting technical requirements, including a low rolling resistance, a high wear resistance, a high dry grip and a high wet grip. By adding reinforcing filler silica in rubber composition, wet grip ability is now improving, although this approach improves the tire's wet traction capabilities, but the wear performance of the tire but also therefore reduced tire life accordingly reduced. Tires are generally designed to provide high speed performance. Achievement of good winter performance is obtained at the cost of a reduction of handling; good dry traction of a tire can only be obtained by a reduction of winter performance.

Aromatic oil is added into the rubber composition for improving the processing characteristics and grip properties of the rubber vulcanizate. Conventional oil processing aids have been used in many tire components: tread compounds often contain polybutadiene rubber ("BR"), oil-extended polybutadiene rubber ("OE- BR"), styrene-butadiene rubber ("SBR"), oil-extended styrene-butadiene rubber ("OE-SBR"), isoprene-butadiene rubber ("IBR"), and styrene-isoprene-butadiene rubber ("SIBR"); sidewall and ply coats can contain butyl rubber and SBR and may use free aromatic oils as processing aids; internal components, such as the steel belt skim coat, gum strips, cushions, barriers, bases, and wedges, contain predominantly natural rubber and aromatic oils. Generally, the raw ingredients and materials used in tire compounding impact all tire performance variables, thus, any alternative to conventional processing oils, such as naphthenic, paraffinic, and aromatic oils must be compatible with the rubbers, not interfere with cure, be easily dispersed in all tire compounds, be cost effective, and not adversely impact tire performance.

Reference made to the following inventions:
IN publication no. 992/DEL/2010 relates to a green rubber composition and process for manufacture thereof wherein the composition includes partially cross-linked triglycerides which enable obviating the need for petroleum based rubber processing oils, synthetic plasticizers, dispersing agents as well as expensive silane coupling agents generally used for coupling of silica to rubber composition having silica/silicates/mineral fillers as reinforcing fillers. The said partially cross-linked triglycerides has sulphur level below 10% and is manufactured by heating to 150°C to 200°C, a non-petroleum oil having Iodine number 60 to 180 in the presence of sulphur or sulphur donor or peroxide or any combination thereof and in the presence of an accelerator. Whereas partial cross-linking of triglycerides with sulphur monochloride is carried out by reacting said non-petroleum oils with sulphur monochloride at below room temperature, in the presence of an accelerator.

IN publication no. 201747043338 provides a fluid having a boiling point in the range of from 100 to 400 deg C and comprising more than 95% isoparaffins and containing less than 100ppm aromatics obtainable by the process comprising the step of catalytically hydrogenating a feed comprising more than 95% by weight of a hydrodeoxygenated isomerized hydrocarbon biomass feedstock at a temperature from 80 to 180° C and at a pressure from 50 to 160 bars.

Publication no. KR20130124664 relates to a rubber compound containing carbonated rice bran. The rubber compound containing carbonated rice bran improves a bonding force with rubber by acid-treating and coupling agent-treating rice bran, thereby minimizing the physical property loss and improving the consumption efficiency and wet braking performance of tire.

Publication no.JP2017031418 provides an improved carbon black composition for use in rubber processing, comprising carbon black and a natural oil. A carbon black composition for use in rubber processing comprises carbon black and a natural oil integrated therein. A rubber compound composition comprises the carbon black composition. Preferably natural oil is present in a proportion of 1 to 50 mass% of the carbon black. Preferably natural oil is edible or non-edible vegetable oil. More preferably the natural oil is selected from rice bran oil, neem oil, Karanjia oil, palm oil, mahua oil, or rubber seed oil.

Publication no.KR20110073059 provides a rubber composition for snow tire tread to improve ice traction and wet traction and to ensure excellent hardness. A rubber composition for snow tire tread comprises 100 parts by weight of a base rubber, 1-8 parts by weight of a foaming agent, and 5-20 parts by weight of vegetable powder filler with particle diameter of 10 micron or less. The vegetable powder filler is rice bran. The snow tire comprises rubber prepared using the rubber composition for snow tire tread.

Publication no.JP2006063182 provides a rubber composition having a low hardness and a friction coefficient adjusted in a specified range and a rubber roller. The rubber composition is constituted of a base polymer composed of a single substance of a natural rubber or a synthetic rubber or its mixture and an RB (rice bran) ceramic. The rubber roller 10 has a rubber layer 12 provided around a core metal 11 of a roller axis body, and at least the outermost layer of the rubber layer 12 is formed of the above rubber composition.

Publication no.KR20020076061 provides a tread rubber composition for studless tire, which has a simple manufacturing process, and which can improve friction force and traction power of tire on iced and snowy road without reducing abrasion capability. The tread rubber composition for studless tire comprises, as active ingredient, a carbonized bran, which is produced by burning a bran obtained from rice plant, in order to improve a brake power of tire. The carbonized bran has a size of 0.1-1 mm. The content of the carbonized bran is 5-10 wt% with respect to rubber material. Particularly, the composition comprises 100 wt% of rubber material consisting of 40 wt% of natural rubber, 40 wt% of styrene-butadiene rubber (SBR), and 20 wt% of butadiene rubber; and 75 wt% of carbon black, 25 wt% of oil, 4 wt% of anti-aging agent, 2 wt% of vulcanizing agent, 1.5 wt% of vulcanizing aid, and 5 wt% of carbonized bran.

Publication no. KR970003954 provides rubber material for preventing slide is unified, fused and attached to the vulcanized rubber within a layer of vulcanized rubber. More than 1 component selected among straw, wheat straw, barley straw or rice bran crushed with its average length 0.5~1.0 cm are irregularly distributed in 40~70 wt% ratio uniformly. Therefore, the produced rubber material has a high friction coefficient and prevents slide in a snow or an ice.

Publication no. JPH10219031 provides composition for a studless tire having increased frictional force on a frozen or snowy road to improve the running performance of the tire on the road of the above condition by compounding a diene rubber with rice bran ceramic particles at a specific ratio. This composition is produced by compounding (A) a diene rubber, (B) a carbon black (preferably having a nitrogen adsorption specific surface area N2 SA of 1-200m2/g and a DBP oil absorption of 80-150mL/100g and further (C) an inorganic reinforcing filler such as silica and (D) an oil, etc., and compounding the obtained rubber composition with (E) 1-10 pts. (based on 100 pts. of the component A) of a rice bran ceramic. The component E can be produced e.g., by carbonizing defatted rice bran at a high temperature optionally after impregnating with a resin having a condensed polycyclic aromatic structure such as a phenolic resin. The component E preferably has a representative average particle diameter of 50-500µm and a Vickers hardness of 100-400 on an average.

Publication no.GB501787 provides vulcanization accelerators. Rubber is vulcanized in the presence of a compound having the formula in which R is an aliphatic or aromatic radicle, and R<1> and R<11> are aromatic radicles. The compounds are addition products of guanidines and phenyl isothiocyanate.

Publication no.CN101565517 relates to a modified environmentally-friendly thermoplastic styrene-butadiene rubber outsole material and a preparation method thereof. The outsole material comprises the following substances by weight portion: 40 to 60 portions of thermoplastic elastomer, 20 to 30 portions of dry rubber modifier, 10 to 20 portions of filler, 5 to 10 portions of strengthening agent, 15 to 30 portions of stuffing, 10 to 15 portions of softener, 3 to 5 portions of modifier and 0.3 to 0.5 portions of adhesion preventive. The filler is rice bran. In modified environmentally-friendly thermoplastic styrene-butadiene rubber outsole material, the rice bran is used to replace calcium carbonate, so environmental-protection requirements are met completely; the added rice bran having a crude fiber content of 6.0 to 9.0 percent increases the wear resistance of outsole NBS, improves the wear resistance of outsoles and makes the wear resistance rate of the outsole material reach 60 to 65 percent; and the full-cream rice bran is used to replace the calcium carbonate, so the outsole has the natural and unique flavor of the rice bran and can be accepted more easily by customers.

Publication no.CN104719637 relates to application of rubber seed oil to sturgeon compound feed and a formula of the rubber seed oil. The rubber seed oil is substituted for soybean oil partially to be added into the sturgeon compound feed. The compound feed comprises, by weight, 12-16% of fish meal, 18-22% of bean pulp, 12-17% of rapeseed dregs, 13-18% of cottonseed meal, 5-8% of corn gluten meal, 10-14% of rice bran, 0-5.5% of the soybean oil, 2.7-8.2% of the rubber seed oil, 0.3-0.5% of soya bean lecithin, 0.8-1.2% of monocalcium phosphate, 0.02-0.05% of vitamin C phosphate, 0.1-0.3% of choline chloride ,0.01-0.03% of ethoxyquin, 0.5-1.0% of mineral substance premix and 0.5-1.0% of vitamin premix. The sum of weight percentages of all raw materials is 100%. The application of the rubber seed oil to the sturgeon compound feed and the formula of the rubber seed oil have the advantages that the rubber seed oil is fully utilized to serve as a fat source in the sturgeon compound feed, the soybean oil as feed grease in short supply is saved, and the compound feed has no bad influence on sturgeon; formula cost and feed factors are reduced, high cost performance is achieved, and culture benefit of the sturgeon is improved.

Publication no.CN104387745 discloses a heat-resistant abrasion-resistant rubber composition. The composition comprises the following substances in parts by weight: 55-70 parts of polycarbonate, 12-35 parts of N-N'-diphenyl-p-phenylenediamine, 3-9 parts of epoxy rice bran oleic acid butyl ester, 5-15 parts of hypochlorous acid, 10-20 parts of trimethyl citrate, 1-4 parts of fumed silica, 35-41 parts of nitrile rubber, 11-14 parts of modified diatomite, 17-34 parts of natural rubber, 3-6 parts of epoxidized acetyl linoleic acid methyl ester and 6-9 parts of a hindered phenolic antioxidant. The heat-resistant abrasion-resistant rubber composition has excellent fatigue and aging resistance, can be used for long term under the state of fatigue, and has good heat resistance, tearing resistance, chemical corrosion resistance and abrasion resistance and long service life.

Publication no.CN105504434 relates to a cable material, in particular to a high-toughness fire-resistant composite styrene-butadiene rubber cable material and a preparation method thereof. The cable material is prepared from, by weight, 30-40 parts of high-density polyethylene, 40-50 parts of styrene-butadiene rubber, 2-3 parts of sodium sulfanilate, 1-3 parts of ethylene diamine tetra (methylene phosphonic acid) sodium, 5-8 parts of rice bran wax, 2-3 parts of vinyltriethoxysilane, 1-2 parts of an antioxidant 1035, 3-6 parts of rosin, 4-6 parts of polymeric ferric sulfate, 12-15 parts of epoxidized methyl acetoricinoleate, 12-18 parts of calcium aluminate, 20-25 parts of nanometer zirconium dioxide, 3-5 parts of ethylene glycol monostearate, 10-12 parts of color masterbatch and 2-3 parts of an additive. The cable material improves the mechanical properties of single polyethylene resin, and the modified nanometer zirconium dioxide powder in the raw materials plays a more efficient reinforcement effect.

Publication no.CN105440686 discloses a damping high-temperature resistant rubber material. Raw materials of the damping high-temperature resistant rubber material comprise, by weight, 50-70 parts of silicone rubber, 20-30 parts of chlorinated butyl rubber, 10-20 parts of epoxidized natural rubber, 50-70 parts of a composite filler, 0.8-1 part of 3-aminopropyltriethoxysilane, 20-30 parts of aluminium hydroxide, 8-10 parts of micro-capsulated red phosphorus, 10-20 parts of epoxy rice bran oleic acid butyl ester, 10-20 parts of epoxy silkworm chrysalis oleic acid butyl ester, 1-2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 0.2-0.4 part of a promoter TMTD, 0.1-0.2 part of a promoter M, 2-4 parts of a rare earth stabilizer, 2-4 parts of a Ca/Zn compound stabilizer, 0.05-0.1 part of an antioxidant 1010, 0.2-0.4 part of an antioxidant 264 and 2-4 parts of paraffin. The damping high-temperature resistant rubber material of the invention has good damping performance, good high temperature resistance and good mechanical property.

Several rubber compositions known in the art use rubber processing oils as softening agent particularly when precipitated silica is used as a reinforcing filler. The drawback of such compositions is that such rubber processing oils are derived from petroleum which is a non-renewable resource. Further, such rubber processing oils may contain a variety of potentially harmful components such as aromatic compounds, the removal of which by hydro-treatment may significantly increase the cost.

Hence there is a need for a high-performance green tyre composition having lower rolling resistance.

In order to overcome above listed prior art, the present invention aims to provide a high-performance motorcycle tire tread composition with lower rolling resistance, and its method of preparation.

OBJECT OF THE INVENTION
The principal object of the present invention is to provide a high-performance motorcycle tire tread composition and its method of preparation.

Another object of the present invention is to provide a green tire tread composition using rice bran oil or mustard oil.

Yet another object of the present invention is to eliminate / reduce the use of processing oils containing high polynuclear aromatic hydrocarbon.

Yet another object of the present invention is to provide motorcycle tire tread composition having lower rolling resistance.

Still another object of the present invention is to provide motorcycle tire tread composition having high rubber elasticity.

Still another object of the present invention is to provide motorcycle tyre tread composition having high abrasion resistance.

Still another object of the present invention is to provide motorcycle tyre tread composition provides better processing properties.

SUMMARY OF THE INVENTION
One or more problems of the conventional prior arts may be overcome by various embodiments of the present invention.

It is a primary aspect of the present invention to provide a tire tread rubber composition, comprising of:
polymer matrix – 100 phr;
reinforcing fillers – 5-85 phr;
coupling agent – 2.5 – 8.5 phr;
processing aid – 1-30 phr;
anti-degradants – 0.5 – 8.5 phr;
vulcanization activator – 2-10 phr;
vulcanization agent – 1.5 – 3.5 phr; and
accelerators – 0.5 – 5.5 phr,
wherein the processing aid is selected from rice bran oil, mustard oil and combinations thereof,
wherein the processing aid is selected from rice bran oil containing oleic acid 34-40% and linoleic acid 30-39%, and
wherein the processing aid is selected from mustard oil containing oleic acid 20-30% and linoleic acid 10-15%.

It is another aspect of the present invention to provide a tire tread rubber composition, wherein rubbers are selected from natural rubber, non-oil extended solution styrene butadiene rubber, poly butadiene rubber and combinations thereof.

It is another aspect of the present invention to provide a tire tread rubber composition, wherein rubbers are selected from natural rubber – 5 – 25 phr, solution styrene butadiene rubber – 25-75 phr, and poly butadiene rubber – 20 – 50 phr.

It is another aspect of the present invention to provide a tire tread rubber composition, wherein the reinforcing filler is selected from carbon black, precipitated silica and combinations thereof, preferably in a weight ratio of carbon black – 5 – 70 phr and precipitated silica – 25 – 85 phr.

It is another aspect of the present invention to provide a tire tread rubber composition, wherein coupling agent is selected from SI75.

It is another aspect of the present invention to provide a tire tread rubber composition, wherein the antidegradant is selected from 6PPD [N-(1,3-dimethyl butyl)-N’-phenyl-p-phenylene diamine], Microcrystalline wax (MC-Wax), 2,2,4-trimethyl-1,2-dihydroquinoline (oligomers) (TDQ) and combinations thereof, preferably in a weight ratio of 6PPD - 0.5 – 3 phr, MC wax – 0.5 – 2.5 phr, and TDQ – 1-3 phr.

It is another aspect of the present invention to provide a tire tread rubber composition, wherein the vulcanization activator is selected from zinc oxide and stearic acid, preferably in a weight ratio of zinc oxide – 2-5 phr, and stearic acid – 2- 5 phr.

It is another aspect of the present invention to provide a tire tread rubber composition, wherein the vulcanization agent is sulphur.

It is another aspect of the present invention to provide a tire tread rubber composition, wherein the accelerators are selected from N-cyclohexyl-2-benzothiazole sulfonamide [CBS], diphenyl guanidine [DPG] and combinations thereof, preferably in a weight ratio of CBS – 1-3 phr, and DPG- 0.5-2.5 phr.

It is another aspect of the present invention to provide a method for preparation of tire tread rubber composition, comprising of the steps:
Preparation of master batch,
initial mixing of rubbers;
mixing and reacting with 80 – 90% of the reinforcing filler carbon black and 80 – 90% of the inorganic reinforcing filler silica, silane coupling agent Si75, and allowed for silanisation at temperature range between 110 °C and 125 °C at a rotor speed of 20 – 30 rpm;
adding and reacting 10-20% of carbon black and silica, along with processing aid, TDQ, MC wax, stearic acid;
sweeping down in the orifice, mixing and dumping of the rubber compound at a temperature range between 150 °C and 165 °C; and
sheet out the rubber compound, reacting with zinc oxide and 6PPD and dumping at a temperature range between 135 °C and 150 °C,
sheet out the rubber compound, and allowed to mix for 120 to 180 seconds and dumped at the temperature range of 135°C to 150°C,
Preparation of final batch,
mixing and reacting master batch compounds with curatives sulphur, CBS and DPG and dumping at a temperature range between 85 °C and 115 °C; and
sheet out the rubber compound,
wherein the processing aid is selected from rice bran oil, mustard oil and combinations thereof,
wherein the processing aid is selected from rice bran oil containing oleic acid 34 – 40% and linoleic acid 30-39%, and
wherein the processing aid is selected from mustard oil containing oleic acid 20 – 30% and linoleic acid 10 – 15%.

It is another aspect of the present invention to provide the method for preparation of tire tread rubber composition, wherein the processing parameters for final batch mixing in Banbury mixer includes rotation speed of 50 to 60 rpm, temperature range between 65 °C and 85 °C, and ram pressure of 4 to 5 kp /sq.cm.

It is another aspect of the present invention to provide the method for preparation of tire tread rubber composition, wherein the processing parameters for master batch mixing in Banbury mixer includes rotation speed of 50-60 rpm, temperature range between 65 °C and 90 °C, and ram pressure of 4 to 5 kp/sq.cm.

BRIEF DESCRIPTION OF DRAWINGS
Figure 1 and 2 represents the ATR FTIR spectra of Rice bran oil and Mustard oil.

DETAILED DESCRIPTION OF THE INVENTION
Source and geographical origin of biological material used in the present invention:
Rice bran oil – Rice bran oil is extracted from the outer bran or husk of rice grains. It is obtained from Vaighai Agro Products Limited, 39(B) Vaighai house, Anna Nagar, Madurai -625020, Tamilnadu, India.

Mustard oil – Mustard oil is extracted from the seeds of mustard plants. It is obtained from Sree Ram Agencies, Old No 2, (New no 1B) Palmal Cross Street near Mahal South, Madurai - 625001, Tamilnadu, India.

The present invention relates to the high-performance motorcycle tire tread composition having low rolling resistance and its method of preparation thereof. The present invention provides a tyre produced using the rubber composition, capable of providing better rubber processing properties.

The composition for motorcycle tyre treads, comprises one or more diene rubbers; reinforcing fillers carbon black and silica; coupling agent; activators; anti-degradants; vulcanization agent; primary accelerators; processing aid rice bran oil or mustard oil. The present invention relates to a high performance motor cycle green tyre treads for a tyre and to rubber compositions intended for the manufacture thereof:
a) The motor cycle tyre tread composition acccording to the invention, comprising 100 parts by weight of a rubber(s), comprises 100 phr of a natural rubber, non oil extended solution styrene butadiene rubber and polybutadiene rubber.
b) Reinforcing filler, ASTM grades of carbon black having the Iodine adsorption No. 76 to 165 mg/gm and with the blend of another reinforcing inorganic filler silica for the present invention is to provide a high performance motor cycle green tyre treads.
c) In order to couple the inorganic filler silica to the diene elastomer, bi functional organosilane coupling agent SI75 is used to provide a satisfactory bonding of, chemical/or physical nature between the inorganic filler and diene elastomer (s).
d) Aromatic oil, Elasto 710 grade is used in the control compound to compare with rice bran oil containing oleic acid 34 to 40%, linoleic acid 30 to 39% or mustard oil containing 20 to 30% oleic acid, 10 to 15% of linoleic acid and FTIR spectra of Rice bran oil and Mustard oil at IR region of 3100 to 540 cm -1 studied in the frequency regions of 3007?cm-1 (attributed to the stretching vibration of =CH cis), 2923 cm-1 due to asymmetrical stretching vibration of –CH(CH2), 2854?cm-1 due to symmetrical stretching vibrations of –CH(CH2), 1744 cm-1 due to stretching vibration of -C=O(ester group), 1463?cm-1 because of the –C-H(CH2) bending, 1377 cm-1 due to symmetrical bending of -CH(CH3) and 1098?cm-1 which are corresponding to C–O stretching vibrations as well as at 722?cm-1 (cis –CH=CH– bending out of plane) is used in the present invention to produce a high performance motorcycle green tyre tread composition.
e) The other ingredients selected for the present invention is based on the conventional motorcycle tyre tread composition antidegradant 6PPD and MC Wax to protect against degradation by ozone is added to the rubber composition to provide resistance to thermo-oxidative ageing of elastomers and a non-staining antioxidant TDQ is added to the rubber composition to provide resistance to thermo-oxidative ageing of elastomers.
f) Also, vulcanization activator zinc oxide and stearic acid are added to form zinc soap, improves the solubility of zinc oxide in the compound, and with the accelerator to form a complex, this complex reacts with sulphur to produce a strong cure activating system.
g) The vulcanization system used in the present invention is based on sulphur and a primary accelerator CBS and a secondary accelerator DPG is used to activate the primary accelerator.

Table 1: Rubber compositions in phr
Ingredients F1, phr F1-I, phr F1-II, phr F2, phr F2-I, phr F2-II, phr
RSS 3 1 20.00 20.00 20.00 20.00 20.00 20.00
SSBR HPR850 R 2 50.00 50.00 50.00 50.00 50.00 50.00
PBR 1220 3 30.00 30.00 30.00 30.00 30.00 30.00
CB N330 4 35.00 35.00 35.00 35.00 35.00 35.00
Precipitated silica 5 30.00 30.00 30.00 30.00 30.00 30.00
SI 75 6 3.00 3.00 3.00 3.00 3.00 3.00
Zinc oxide 7 2.75 2.75 2.75 2.75 2.75 2.75
Stearic acid 8 1.75 1.75 1.75 1.75 1.75 1.75
MC Wax 9 0.75 0.75 0.75 0.75 0.75 0.75
6PPD 10 0.75 0.75 0.75 0.75 0.75 0.75
TDQ 11 1.0 1.0 1.0 1.0 1.0 1.0
Aromatic oil 12 5.00 15.00 25.00 - - -
Rice bran oil 13 - - - 5.00 15.00 25.00
Mustard oil 14 - - - - - -
DPG 15 0.50 0.50 0.50 0.50 0.50 0.50
Sulphur 16 2.20 2.20 2.20 2.20 2.20 2.20
CBS 17 1.70 1.70 1.70 1.70 1.70 1.70
Total 184.4 194.40 204.40 184.40 194.40 204.40
Table 2: Rubber compositions in phr
Ingredients F1, phr F1-I, phr F1-II, phr F3, phr F3-I, phr F3-II, phr
RSS 3 1 20.00 20.00 20.00 20.00 20.00 20.00
SSBR HPR850 R 2 50.00 50.00 50.00 50.00 50.00 50.00
PBR 1220 3 30.00 30.00 30.00 30.00 30.00 30.00
CB N330 4 35.00 35.00 35.00 35.00 35.00 35.00
Precipitated silica 5 30.00 30.00 30.00 30.00 30.00 30.00
SI 75 6 3.00 3.00 3.00 3.00 3.00 3.00
Zinc oxide 7 2.75 2.75 2.75 2.75 2.75 2.75
Stearic acid 8 1.75 1.75 1.75 1.75 1.75 1.75
MC Wax 9 0.75 0.75 0.75 0.75 0.75 0.75
6PPD 10 0.75 0.75 0.75 0.75 0.75 0.75
TDQ 11 1.0 1.0 1.0 1.0 1.0 1.0
Aromatic oil 12 5.00 15.00 25.00 - - -
Rice bran oil 13 - - - - - -
Mustard oil 14 5.00 15.00 25.00
DPG 15 0.50 0.50 0.50 0.50 0.50 0.50
Sulphur 16 2.20 2.20 2.20 2.20 2.20 2.20
CBS 17 1.70 1.70 1.70 1.70 1.70 1.70
Total 184.4 194.40 204.40 184.40 194.40 204.40

1. RSS 3 – RSS 3 (Natural Rubber - Ribbed Smoke Sheet) from Southland Global PTE Ltd, Thailand with the Mooney Viscosity, ML (1+4) at 100°C is 74 MU.
2. SSBR HPR850 R is non-oil extended solution styrene butadiene rubber (SSBR) with 27.5 % of styrene content, 59.5 of vinyl content and Tg of -24°C from JSR corporation, Japan.
3. PBR 1220 - from Reliance Industries Ltd, India with the Mooney viscosity, ML (1+4) @ 100°C is 44 MU
4. Carbon Black N330- ASTM Grade Aljubail Carbon, Saudi Arabia. It is the reinforcing filler HAF, High Abrasion Furnace having the Iodine adsorption No. 77 to 87 mg/gm, tinting strength value between to 99 to 109 % ITRB, statistical thickness surface area value between 70 to 80 m2/gm
5. Precipitated Silica - Ultrasil VN3 silica from Insilico Ltd, Evonik Industries GmbH, India. It is the reinforcing filler having nitrogen surface area value 170 to 190 m2/gm
6. Si75 - Bifunctional, sulfur-containing organosilane from Evonik Resource efficiency GmbH, Germany.
7. Zinc Oxide from POCL Enterprises Limited, India. It is an activator added to the rubber compound to activate sulphur vulcanization.
8. Stearic acid – from 3F Industries Ltd., India. It is used as a Process aid. Also, Zinc oxide and Stearic acid are added to form zinc soap, improves the solubility of zinc oxide in the compound, and with the accelerator to form a complex, this complex reacts with sulphur to produce a strong cure activating system.
9. MC Wax – Microcrystalline Wax from Gujarat Paraffins Limited, India. It is added to the rubber composition to provide resistance to thermo-oxidative ageing of elastomers.
10. 6PPD - (N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine) from Nocil Limited, India.
11. TDQ- 2, 2, 4 – trimethyl1-1, 2-dihydroquinoline (Oligomers) from Nocil Limited, India.
12. Aromatic Oil - Aromatic Oil from Indian Oil Corporation Limited, India
13. Rice bran Oil – It is from Vaighai Agro Products Limited, Madurai, India having iodine value ranging from 90 to 105 (I2/100 gm of oil) and its saponification value is ranging from 180 to 195.
14. Mustard Oil – It is from Sree Ram Agencies, Madurai, India having iodine value ranging from 92 to 108 and its saponification value ranging from 168 to 177.
15. DPG - Diphenyl guanidine from PMC Rubber Chemicals India Pvt ltd, West Bengal, India. It is a secondary accelerator, used to activate the primary accelerator.
16. Sulphur is the vulcanizing agent from The Standard Chemical Co. Pvt Ltd, India.
17. CBS- N-cyclohexyl-2-benzothiazolesulfenamide) from Nocil Limited, India. It is a delayed action accelerator suitable for diene rubbers.

Method of Preparation of the Rubber Compositions:
Mixing Sequence:
Using a Banbury mixer with the tangential rotor (Make: Werner & Pfleiderer & Model: GK2VK), a rubber composition is prepared by a thermomechanical process is as follows:
Preparation of master batch:
Step I: Preparation of masterbatch has been performed with the rotation speed of the mixer between 50 to 60 rpm and with the head temperature of the Banbury maintained between 65 °C to 90°C and with the ram pressure of 4.0 to 6.0 KP/cm2 a) Mixing chamber has been charged with the NR, SSBR and PBR and allowed to mix for 0 to 45 seconds b) Further by adding 80 to 90% of the reinforcing filler carbon black and 80 to 90% of the inorganic reinforcing filler silica, silane coupling agent Si75, and allowed to mix for 60 seconds for silanisation at around 110 °C to 125°C, c) the process of silanisation has been done with the reduced rotor speed 20 to 30 rpm d) The remaining carbon black and silica, along with aromatic oil or rice bran oil or mustard oil, rubber chemicals TDQ, MC wax, stearic acid, except 6PPD and zinc oxide are added, and allowed to mix for 50 to 120 seconds e) sweeping done in the orifice and allowed to mix for another 50 to 60 seconds and the compound has been dumped at the temperature in the range of 150°C to 165°C. The compound has been sheeted out in the laboratory two-roll mill.
Step II: Mixing chamber of Banbury charged with the Step I master batch, chemicals zinc oxide and 6PPD, and allowed to mix for 180 seconds and dumped in the temperature range of 135°C to 150°C. The compound has been sheeted out in the laboratory two-roll mill.
Step III: Mixing chamber of Banbury charged with the Step II master batch, and allowed to mix for 120 to 180 seconds and dumped at the temperature range of 135°C to 150°C. The compound has been sheeted out in the laboratory two-roll mill.
Preparation of Final Batch: Preparation of masterbatch has been performed with the rotation speed of the mixer between 50 to 60 rpm and with the head temperature of the Banbury maintained between 65 °C to 85°C and with the ram pressure of 4.0 to 5.0 Kp/cm2. Mixing chamber charged with the Step III master batch and the curatives Sulphur, CBS, DPG are added, and allowed to mix for 60 to 90 seconds and dumped at the temperature range of 85°C to 115°C. Final sheet out has been done in the laboratory mill.

Results:
Characterization of Cured Rubber Vulcanizate and Uncured Rubber Compound:
The Compound Properties are listed in Table 3 and Table 4:
Table 3: Characterization of Uncured Rubber Compound and Cured Rubber Vulcanizates
Physico
Mechanical Properties F1
Control (Aromatic Oil: 5 phr) F2,
(Rice bran Oil:
5 phr) Index F1-I
Control
(Aromatic Oil:
15 phr) F2-I
(Rice bran Oil: 15
phr) Index F1-II
Control
(Aromatic Oil:
25 phr) F2-II
(Rice bran Oil: 25
phr) Index

M1. Mooney Scorch Characteristics of uncured Rubber compound for Processability
Mooney Viscosity, MU (Lower the index value is better) 59.10 55.2 93.40
42.20 38.80 91.94
33.80 28.0 82.84

t5, minutes: minutes
(Ideal value is 18 minutes) 40.27 40.50 - 43.73 42.77 - 51.48 38.67 -
M2. Hardness of the Rubber Vulcanizate
Hardness, Shore A 70 69 - 64 63 - 61 62 -
M3: Dynamic properties of the Rubber Vulcanizate
Rolling Resistance, tan delta at 60°C
(Lower the index value is better) 0.107
0.100 93.46
0.108 0.088
81.48
0.116 0.099 85.34

M4. Abrasion Loss of the Rubber Vulcanizate
Abrasion Loss, mm3 (Lower the index value is better) 66.38 59.23 89.23
80.34 62.18 77.40
91.81 63.38 68.96

M5. Rubber Elasticity of the Rubber Vulcanizate
Rebound Resilience at 23+/- 2 Deg C, % (Higher the index value is better) 52.28 55.63 104.80
52.10 56.67 108.77
52.38 59.14 112.90

Table 4: Characterization of Uncured Rubber Compound and Cured Rubber Vulcanizates
Properties F1
Control (Aromatic Oil: 5 phr) F3,
(Mustard Oil: 5 phr) Index F1-I
Control
(Aromatic Oil: 15 phr) F3-I
(Mustard Oil: 15 phr) Index F1-II
Control
(Aromatic Oil: 25 phr) F3-II
(Mustard Oil: 25 phr) Index
M1. Mooney Scorch Characteristics of Uncured Rubber compound for Processability
Mooney Viscosity, MU (Lower the index value is better) 59.10 53.40 90.36
42.20 40.00
94.79 33.80 30.60 90.53

t5, minutes: minutes (Ideal value is 18 minutes) 40.27 40.72 - 43.73 44.83 - 51.48 44.47 -
M2. Hardness of the Rubber Vulcanizate
Hardness, Shore A 70 69 - 64 63 - 61 57 -
M3: Dynamic Properties of the Rubber Vulcanizate
Tan delta @ 60 deg C, (Lower the index value is better) 0.107 0.096 89.72
0.108 0.096 88.89
0.116 0.100 86.20

M4: Abrasion Loss of the Rubber Vulcanizate
Abrasion Loss, mm3 (Lower the index value is better) 66.38 60.95 91.82
80.34 65.37 81.37
91.81
54.68 59.56

M5: Rubber Elasticity of the Rubber Vulcanizate
Rebound Resilience at 23+/-2 Deg C, % (Higher the index value is better) 52.28 60.95 116.58
52.10 58.28 111.86
52.38 59.81 114.18

Results
Measurements and tests (Table 3):
The purpose of these tests is to measure the improved properties of the rubber compositions related to the invention against control rubber composition. For this, six compositions F1, F1-I, F1-II, F2, F2-I & F2-II are prepared based on NR: SSBR: PBR (20 phr :50 phr :30 phr) blend rubber composition reinforced by carbon black and silica as fillers containing naturally occurring rice bran oil against NR: SSBR: PBR (20 phr:50 phr:30 phr) blend reinforced by carbon black and silica as fillers containing process aid aromatic oil (F1, F1-I & F1-II) are prepared and evaluated.

The present invention provides a 100 parts by weight of rubber composition F2, F2-I, F2-II NR: SSBR: PBR (20 phr :50 phr :30 phr) blend based rubber compositions containing rice bran oil 5 phr, 15 phr and 25 phr gave better processing characteristics i.e., Mooney viscosity values lowered by 6.6%, 8.06% and 17.16% respectively which indicates the oil compatibility with polymer matrix when compared to NR: SSBR: PBR (20 phr:50 phr:30 phr) blend based rubber compositions reinforced by carbon black and silica as fillers containing process aid aromatic oil of 5 phr, 15 phr and 25 phr respectively. Also, 100 parts by weight of rubber composition F2, F2-I, F2-II NR: SSBR: PBR blend (20 phr :50 phr: 30 phr) based rubber compositions reinforced by carbon black and silica as fillers containing naturally occurring process aid rice bran oil 5 phr, 15 phr and 25 phr gave process safety i.e., t5 value is greater than 15 minutes (Ideal value of tread compound for better processability is greater than or equal to 18 minutes) like NR: SSBR: PBR (20 phr:50 phr:30 phr) blend based rubber compositions reinforced by carbon black and silica as fillers containing process aid aromatic oil (F1, F1-I & F1-II) 5 phr, 15 phr and 25 phr respectively.

Moreover, the present invention provides a 100 parts by weight of rubber composition F2, F2-I, F2-II NR: SSBR: PBR (20 phr :50 phr :30 phr) blend based rubber compositions containing rice bran oil 5 phr, 15 phr and 25 phr gave hardness value 69, Shore A, 63 Shore A and 61 Shore A when compared to NR: SSBR: PBR (20phr:50phr:30phr) blend based rubber compositions reinforced by carbon black and silica containing aromatic oil of 5 phr, 15 phr and 25 phr gave 70 Shore A, 64 Shore A and 61 Shore A respectively.

The present invention provides a 100 parts by weight of rubber composition F2, F2-I, F2-II NR: SSBR: PBR (20 phr :50 phr :30 phr) blend based rubber compositions reinforced by carbon black and silica as fillers containing naturally occurring process aid rice bran oil of 5 phr, 15 phr and 25 phr gave lowered tan delta value at 60 °C by 6.54%, 18.52%, 14.66% respectively when compared to NR: SSBR: PBR (20 phr:50 phr:30 phr) blend based rubber compositions reinforced by carbon black and silica as fillers containing process aid aromatic oil of 5 phr, 15 phr and 25 phr respectively i.e., NR: SSBR: PBR (20 phr:50 phr:30 phr) blend based tread rubber compositions reinforced by carbon black and silica as fillers containing 5 to 25 phr of naturally occurring process aid rice bran oil provides lower rolling resistance ranging from 6.54 % to 18.52%.

The present invention provides a 100 parts by weight of rubber composition F2, F2-I, F2-II NR: SSBR: PBR (20 phr :50 phr :30 phr) blend based rubber compositions reinforced by carbon black and silica as fillers containing naturally occurring process aid rice bran oil of 5 phr, 15 phr and 25 phr gave lowered abrasion loss value 10.77%, 22.60% and 31.04% respectively when compared to NR: SSBR: PBR (20:50:30) blend based rubber compositions reinforced by carbon black and silica as fillers containing process aid aromatic oil of 5 phr, 15 phr and 25 phr respectively i.e., NR: SSBR: PBR (20:50:30) blend based tyre tread rubber compositions containing naturally occurring rice bran oil of 5 to 25 phr provides improved wear resistance ranging from 10.77 % to 31.04 %.

The present invention provides a 100 parts by weight of rubber composition F2, F2-I, F2-II NR: SSBR: PBR (20 phr :50 phr :30 phr) blend based rubber compositions reinforced by carbon black and silica as fillers containing naturally occurring process aid rice bran oil 5 phr, 15 phr and 25 phr provides high rubber elasticity 4.80%, 8.77% and 12.90% respectively when compared to NR: SSBR: PBR (20 phr:50 phr:30 phr) blend based rubber compositions reinforced by carbon black and silica as fillers containing process aid aromatic oil of 5 phr, 15 phr and 25 phr respectively.

Overall, the present invention provides a 100 parts by weight of rubber composition F2, F2-I, F2-II NR: SSBR: PBR (20 phr :50 phr :30 phr) blend-based tyre tread rubber compositions reinforced by carbon black and silica as fillers containing naturally occurring process aid rice bran oil ranging from 5 phr to 25 phr provides lower rolling resistance along with high abrasion resistance, high rubber elasticity, better processing characteristics and process safety. Also, 100 parts by weight of rubber composition F2, F2-I, F2-II NR: SSBR: PBR (20 phr :50 phr :30 phr) blend-based tyre tread rubber compositions reinforced by carbon black and silica as fillers containing naturally occurring process aid rice bran oil having shore A hardness ranging from 69 Shore A to 61 Shore A.

Measurements and Tests (Table 4):
The purpose of these tests is to measure the improved properties of the rubber compositions related to the invention against control rubber composition. For this, six compositions F1, F1-I, F1-II, F3, F3-I & F3-II were prepared based on NR: SSBR: PBR (20 phr :50 phr :30 phr) blend reinforced by carbon black and silica as fillers containing naturally occurring process aid mustard oil (F3, F3-I & F3-II) against NR: SSBR: PBR (20 phr :50 phr:30 phr) blend based rubber composition reinforced by carbon black and silica as fillers containing process aid aromatic oil (F1, F1-I & F1-II) are prepared and evaluated.

The present invention provides a 100 parts by weight of rubber compositions F3, F3-I, F3-II NR: SSBR: PBR (20 phr :50 phr :30 phr) blend based rubber compositions containing mustard oil of 5 phr, 15 phr and 25 phr gave better processing characteristics i.e., Mooney viscosity values lowered by 9.64%, 5.21% and 9.47% respectively which indicates the oil compatibility with polymer matrix when compared to NR: SSBR: PBR (20 phr:50 phr:30 phr) blend based rubber compositions reinforced by carbon black and silica as fillers containing process aid aromatic oil of 5 phr, 15 phr and 25 phr respectively. Also, 100 parts by weight of rubber composition F3, F3-I, F3-II NR: SSBR: PBR blend (20 phr :50 phr: 30 phr) based rubber compositions reinforced by carbon black and silica as fillers containing naturally occurring mustard oil 5 phr, 15 phr and 25 phr gave process safety i.e., t5 value is greater than 18 minutes (Ideal value of tread compound for better processability is greater than or equal to 18 minutes) like NR: SSBR: PBR (20 phr:50 phr:30 phr) blend based rubber compositions reinforced by carbon black and silica as fillers containing process aid aromatic oil of (F1, F1-I & F1-II) 5 phr, 15 phr and 25 phr respectively.

Moreover, the present invention provides a 100 parts by weight of rubber composition F3, F3-I, F3-II NR: SSBR: PBR (20 phr :50 phr :30 phr) blend based rubber compositions reinforced by carbon black and silica as fillers containing naturally occurring mustard oil of 5 phr, 15 phr and 25 phr gave hardness value 69 Shore A, 63 Shore A and 57 Shore A when compared to NR: SSBR: PBR (20:50:30) blend based rubber compositions reinforced by carbon black and silica as fillers containing process aid aromatic oil of 5 phr, 15 phr and 25 phr gave 70 Shore A, 64 Shore A and 61 Shore A respectively.

The present invention provides a 100 parts by weight of rubber composition F3, F3-I, F3-II NR: SSBR: PBR (20 phr :50 phr :30 phr) blend based rubber compositions reinforced by carbon black and silica containing naturally occurring process aid mustard oil of 5 phr, 15 phr and 25 phr gave lowered tan delta value at 60°C by 10.28%, 11.11%, 13.80% respectively when compared to NR: SSBR: PBR (20 phr :50 phr:30 phr) blend based rubber compositions reinforced by carbon black and silica as fillers containing process aid aromatic oil of 5 phr, 15 phr and 25 phr respectively i.e., NR: SSBR: PBR (20 phr :50 phr:30 phr) blend based tyre tread rubber compositions reinforced by carbon black and silica containing naturally occurring process aid mustard oil of 5 to 25 phr provides lower rolling resistance ranging from 10.28 % to 13.80%.

The present invention provides a 100 parts by weight of rubber compositions F3, F3-I, F3-II NR: SSBR: PBR (20 phr :50 phr :30 phr) blend based rubber compositions reinforced by carbon black and silica as fillers containing mustard oil of 5 phr, 15 phr and 25 phr gave lowered abrasion loss value like 8.18%, 18.63% and 40.44% respectively when compared to NR: SSBR: PBR (20 phr :50 phr :30 phr) blend based rubber compositions reinforced by carbon black and silica as fillers containing process aid aromatic oil of 5 phr, 15 phr and 25 phr respectively i.e., NR: SSBR: PBR (20 phr:50 phr:30 phr) blend based tyre tread rubber compositions reinforced by carbon black and silica as fillers containing naturally occurring process aid mustard oil of 5 to 25 phr provides improved wear resistance ranging from 8.18 % to 40.44%.

The present invention provides a 100 parts by weight of rubber compositions F3, F3-I, F3-II NR: SSBR: PBR (20 phr :50 phr :30 phr) blend based rubber compositions reinforced by carbon black and silica as fillers containing naturally occurring process aid mustard oil of 5 phr, 15 phr and 25 phr provides high rubber elasticity 16.58%, 11.86% and 14.18% respectively when compared to NR: SSBR: PBR (20:50:30) blend based rubber compositions reinforced by carbon black and silica as fillers containing process aid aromatic oil of 5 phr, 15 phr and 25 phr respectively.

Overall, the present invention provides a 100 parts by weight of rubber composition F3, F3-I, F3-II NR: SSBR: PBR (20 phr :50 phr :30 phr) blend-based rubber compositions reinforced by carbon black and silica as fillers containing naturally occurring process aid mustard oil ranging from 5 phr to 25 phr provides lower rolling resistance along with high abrasion resistance, high rubber elasticity, better processing characteristics and process safety. Also, 100 parts by weight of rubber composition F3, F3-I, F3-II NR: SSBR: PBR (20 phr :50 phr :30 phr) blend-based tyre tread rubber compositions reinforced by carbon black and silica as fillers containing naturally occurring process aid mustard oil having shore A hardness ranging from 69 Shore A to 57 Shore A.

Measurements and Tests:
Better processability (Process Requirements) of a Rubber Compound:
M1. Mooney Scorch Characteristics (pre vulcanization characteristics using large rotor) for processability:
The Mooney Scorch measurements are carried out at 125 °C in a Mooney Viscometer (MV 2000 Alpha technologies, USA) according to ASTM D1646.
a) MV indicates the minimum viscosity, MU
b) t5 indicates the time to scorch (MV+5) which indicates the processing properties (process safety), in minutes: minutes.

M2. Shore A Hardness of the Rubber Vulcanizate:
Shore A Hardness of the Rubber Vulcanizate is assessed in accordance with ASTM D 2240.

M3. Dynamic properties/Visco elastic properties of the Rubber vulcanizate:
The dynamic properties of the rubber vulcanizate are measured on a dynamic mechanical analyzer (DMA Metravib +1000) in tension mode with the temperature sweep -40 °C to 100 °C, Dynamic strain: 0.3%, Static strain:0.6%, Frequency: 10 Hz.
Tan delta at 60°C is a predictor for rolling resistance (Lower tan delta value at 60 °C is good for LRR property).

M4. Abrasion Loss of the Rubber Vulcanizate:
It is measured through Din Abrader, and it is assessed in accordance with ASTM D 5963. Lower the abrasion loss value provide better abrasion resistance. It is the indicator of tyre tread wear resistance property.

M5. Rubber Elasticity of the Rubber Vulcanizate:
It is measured through Rebound resilience tester, and it is assessed in accordance with ASTM D 7121 -DIN 53512.

A green tyre tread rubber composition includes 100 phr of a rubber, with the blend of NR, non-oil extended solution styrene butadiene rubber and butadiene rubber, 5 to 70 phr of carbon black, 25 to 85 phr of reinforcing filler silica, 1 to 30 phr of rice bran oil with the less than equal to flash point 232 °C or mustard oil with the flash point less than or equal to 218 °C and a tyre produced using this composition is capable to provide lower rolling resistance along with high abrasion resistance, high rubber elasticity, better processing characteristics and process safety.

Thus, the invention provides the high rubber elasticity of the rubber vulcanizate.

A tyre produced using this rubber composition is capable to provide lower rolling resistance along with high abrasion resistance, better processing characteristics and process safety. The invention also relates to the high rubber elasticity of the rubber vulcanizate. The naturally occurring Rice bran oil or Mustard oil used in the present invention is eliminates / minimizes the use of processing oils containing high polynuclear aromatic hydrocarbon.
,CLAIMS:WE CLAIM:
1. A tire tread rubber composition, comprising of:
polymer matrix – 100 phr;
reinforcing fillers – 5-85 phr;
coupling agent – 2.5 – 8.5 phr;
processing aid – 1-30 phr;
anti-degradants – 0.5 – 8.5 phr;
vulcanization activator – 2-10 phr;
vulcanization agent – 1.5 – 3.5 phr; and
accelerators – 0.5 – 5.5 phr,
wherein the processing aid is selected from rice bran oil, mustard oil and combinations thereof,
wherein the processing aid is selected from rice bran oil containing oleic acid 34-40% and linoleic acid 30-39%, and
wherein the processing aid is selected from mustard oil containing oleic acid 20-30% and linoleic acid 10-15%.

2. The tire tread rubber composition as claimed in claim 1, wherein rubbers are selected from natural rubber, non-oil extended solution styrene butadiene rubber, poly butadiene rubber and combinations thereof.

3. The tire tread rubber composition as claimed in claim 1, wherein rubbers are selected from natural rubber – 5 – 25 phr, solution styrene butadiene rubber – 25-75 phr, and poly butadiene rubber – 20 – 50 phr.

4. The tire tread rubber composition as claimed in claim 1, wherein the reinforcing filler is selected from carbon black, precipitated silica and combinations thereof, preferably in a weight ratio of carbon black – 5 – 70 phr and precipitated silica – 25 – 85 phr.

5. The tire tread rubber composition as claimed in claim 1, wherein coupling agent is selected from SI75.

6. The tire tread rubber composition as claimed in claim 1, wherein the antidegradant is selected from 6PPD [N-(1,3-dimethyl butyl)-N’-phenyl-p-phenylene diamine], Microcrystalline wax (MC-Wax), 2,2,4-trimethyl-1,2-dihydroquinoline (oligomers) (TDQ) and combinations thereof, preferably in a weight ratio of 6PPD - 0.5 – 3 phr, MC wax – 0.5 – 2.5 phr, and TDQ – 1-3 phr.

7. The tire tread rubber composition as claimed in claim 1, wherein the vulcanization activator is selected from zinc oxide and stearic acid, preferably in a weight ratio of zinc oxide – 2-5 phr, and stearic acid – 2- 5 phr.

8. The tire tread rubber composition as claimed in claim 1, wherein the vulcanization agent is sulphur.

9. The tire tread rubber composition as claimed in claim 1, wherein the accelerators are selected from N-cyclohexyl-2-benzothiazole sulfonamide [CBS], diphenyl guanidine [DPG] and combinations thereof, preferably in a weight ratio of CBS – 1-3 phr, and DPG- 0.5-2.5 phr.

10. A method for preparation of tire tread rubber composition, comprising of the steps:
Preparation of master batch,
initial mixing of rubbers;
mixing and reacting with 80 – 90% of the reinforcing filler carbon black and 80 – 90% of the inorganic reinforcing filler silica, silane coupling agent Si75, and allowed for silanisation at temperature range between 110 °C and 125 °C at a rotor speed of 20 – 30 rpm;
adding and reacting 10-20% of carbon black and silica, along with processing aid, TDQ, MC wax, stearic acid;
sweeping down in the orifice, mixing and dumping of the rubber compound at a temperature range between 150 °C and 165 °C;
sheet out the rubber compound, reacting with zinc oxide and 6PPD and dumping at a temperature range between 135 °C and 150 °C; and
sheet out the rubber compound, and allowed to mix for 120 to 180 seconds and dumped at the temperature range of 135°C to 150°C,
Preparation of final batch,
mixing and reacting master batch compounds with curatives sulphur, CBS and DPG and dumping at a temperature range between 85 °C and 115 °C; and
sheet out the rubber compound,
wherein the processing aid is selected from rice bran oil, mustard oil and combinations thereof,
wherein the processing aid is selected from rice bran oil containing oleic acid 34 – 40% and linoleic acid 30-39%, and
wherein the processing aid is selected from mustard oil containing oleic acid 20 – 30% and linoleic acid 10 – 15%.

11. The method for preparation of tire tread rubber composition as claimed in claim 10, wherein the processing parameters for final batch mixing in Banbury mixer includes rotation speed of 50 to 60 rpm, temperature range between 65 °C and 85 °C, and ram pressure of 4 to 5 kp /sq.cm.

12. The method for preparation of tire tread rubber composition as claimed in claim 10, wherein the processing parameters for master batch mixing in Banbury mixer includes rotation speed of 50-60 rpm, temperature range between 65 °C and 90 °C, and ram pressure of 4 to 5 kp/sq.cm.