A TIRE TREAD RUBBER COMPOSITION USING EGGSHELL POWDER AS A BIOFILLER AND ITS PREPARATION

FIELD OF THE INVENTION

The present invention relates to the field of tire tread rubber composition. The present invention in particular relates to a tire tread rubber composition using eggshell as biofiller and its method of preparation.

BACKGROUND OF THE INVENTION

Natural rubber is natural rubber latex that has been dried and baled. Natural rubber possesses unique properties such as self-reinforcement, abrasion, tear, and impact resistance. These properties make natural rubber ideal for applications such as tires, conveyor belts, hoses, and gaskets.

Similarly, solution-based and emulsion-based styrene butadiene rubbers (SBR) and polybutadiene rubber (PBR) are used in tire components of rubber composition to provide its unique properties like grip, low rolling resistance and wear property. Since polymeric materials do not decompose easily, disposal of waste polymers is a serious environmental problem. Increased consumption of rubber is increasing the rubber waste and hence polluting the environment.

Fillers serve either as inexpensive diluents of the more expensive polymer phase or as reinforcing fillers to improve the physical properties of the rubber product. Diluent fillers must be especially low in cost to be of practical use. Historically, diluent fillers have been made from minerals of various kinds. Reinforcing fillers are expensive, can have high carbon footprints and generally require a very small particle size (< 300 nm). Similarly food waste is used as bio-fillers. The use of food waste bio-fillers for rubber compound would have multiple environmental and economic benefits. Economic benefits include reduction of costs associated with residue treatment, disposal and final cost of polymeric products. Furthermore, many of these bio-fillers, i.e. shells, peels and stems, are lightweight natural structural materials possessing good mechanical properties.

Reference made to the following:

Indian application no. 2366/KOLNP/2008 relates to the rubber composition containing syndiotactic - 1 , 2-polybutadiene having particle diameter of not more than 1.00 nm in the tire tread to improve abrasion resistance without impairing tip cut resistance whereas present invention discusses about the use of an eggshell powder as a bio-filler in the tire tread rubber composition to improve wet grip property.

Publication no. JP2008088380 relates to the rubber composition containing NR, BR, eggshell powder, parabenzoquinone diimine compound as solid foreign substances in the tire tread along with carbon black and silica to provide micro unevenness on the rubber surface, thereby enhancing the performance of tire on ice road surface whereas present invention discusses about the use of eggshell powder as a bio-filler in the tire tread rubber composition to improve wet grip property. Moreover, the present invention doesn't use parabenzoquinone diimine compound in compound design.

Publication no. JPH0641355 discloses the use of rubber composition containing NR, diene based synthetic rubber blended with eggshell powder and carbon black as reinforcing filler in the tire tread rubber composition to improve braking performance on a frozen road surface and snow whereas present invention discusses about the use of eggshell powder as a bio-filler in the tire tread rubber composition to improve wet grip property. Publication no. JP2004346270 relates to the use of rubber composition containing NR, BR, 5-15 parts of eggshell powder along with 30-80 parts of carbon black as a reinforcing filler in the tire tread to improve cornering characteristics on icy and snowy road surfaces and traction characteristics in a front-rear direction whereas present invention discusses about the use of an eggshell powder as a bio-filler in SSBR: BR diblend based tire tread rubber composition to improve wet grip property.

Publication no. US7946323 relates to the use of 75% non-petroleum resources rubber composition (NR: SBR blend, NR: PBR blend, NR, HR: NR blend) instead of petroleum resources in the tire tread to prevent pollution whereas present invention discusses about the use of eggshell powder as a bio-filler in SSBR: PBR diblend based tire tread rubber composition to improve wet grip property.

Application no. IN201917044368 relates to the rubber composition containing crumb rubber as filler in tire tread to use in waterproofing and paving applications whereas present invention discusses about the use of an eggshell powder as a bio-filler in the tire tread rubber composition to improve wet grip property.

Application no. 130/MUMNP/2013 relates to the use of rubber composite containing first component (organic element and thermoplastic element) and second element (vulcanized rubber and tire cords) whereas present invention discusses about the use of an eggshell powder as a bio-filler in the tire tread rubber composition to improve wet grip property.

Reference made to an article entitled “Researchers are using tomato peels and eggshells to make tires” by Marlene Cimons, Ohio State University, 14-03-2017 talks about manufacturing more environmentally-friendly materials complements ongoing efforts to develop sources of clean fuel. Using tomato peels and eggshells as tire filler could help reduce the nation’s dependence on foreign oil, keep food waste out of landfills and make the production of rubber items — especially tires — more sustainable whereas present invention discusses about the use of an eggshell powder as a bio-filler in the tire tread rubber composition to improve wet grip property.

Reference made to an article entitled” Using eggshell as a filler in elastomeric compounds: effect of incubation period on its performance toward elastomers” by Hadi Ramezani Dakhel, Polymer Department, Amirkabir University of Technology, Nov 1, 2008 discuss about the effect of incubation period and the presence of organic membrane on eggshell activity toward elastomers (NBR, NR and SBR) has been investigated. After hatching eggshell (AHES) showed enhanced mechanical properties when compared to before hatching eggshell (BHES) and calcium carbonate. Compounds containing BHES powder also showed good mechanical properties. Both types of eggshells reduced optimum curing time of the compounds. This trend was more considerable in NBR compound. The improvement of mechanical properties of the compounds attributed to elemental composition and higher specific area of AHES. The results of this study showed both before hatching and after hatching eggshell can be used in elastomeric compound as a bio-filler whereas the present invention discusses about the use of an eggshell powder as a biofiller in the tire tread rubber composition to improve wet grip property.

Thus, conventional tread filled with carbon black for tires having high specific surface area have made it possible to achieve a compromise of properties, in terms of rolling resistance, wear resistance and grip which causes considerable carbon footprint. Hence to overcome, there is a need for a bio-filler to reduce carbon footprint for tyre applications which demands a very high wet grip.

In order to overcome above listed prior art, the present invention aims to provide a tire tread rubber composition using eggshell powder as a bio-filler and its method of preparation. OBJECTS OF THE INVENTION:

The principal object of the present invention is to provide a tire tread rubber composition using eggshell powder as a bio-filler and its method of preparation.

Yet another object of invention is use of eggshell powder as a bio-filler in SSBR: PBR blend based tire tread rubber composition.

Yet another object of invention is a partial replacement of conventional fillers like carbon black or silica with eggshell powder or by addition of eggshell powder alongside conventional fillers as a bio-filler in tire tread rubber composition.

Another object of the present invention is to provide a tire tread rubber composition to improve the wet grip.

Another object of the present invention is to provide a tire tread rubber composition to improve low rolling resistance properties.

Another object of the present invention is to provide a tire tread rubber composition to provide better processing properties.

Another object of the present invention is to provide a tire tread rubber composition to reduce carbon footprint.

SUMMARY OF THE INVENTION

One or more problems of conventional prior arts are overcome by various embodiments of the present invention.

It is a primary aspect of the present invention to provide a tire tread rubber composition using eggshell powder, comprising of: Polymer matrix -100 phr; eggshell powder - 3-20 phr; reinforcing fillers - 1-120 phr; coupling agent -0-6 phr; activators - 1-5 phr; low PCA oil - 5-10 phr; anti-degradants - 1.0- 8.5 phr; vulcanizing agent- 1.3-2.5 phr; and primary accelerator - 1.2-2.0 phr, wherein the eggshell powder as a bio-filler in SSBR: PBR diblend and it contains greater than 90% of calcium carbonate and trace of sulphur trioxide and silicon dioxide.

It is another aspect of the present invention to provide a tire tread rubber composition using eggshell powder, wherein polymer matrix is selected as SSBR, PBR and combinations thereof, preferably in a weight ratio of SSBR:PBR - 35-65:65-35 phr.

It is another aspect of the present invention to provide a tire tread rubber composition using eggshell powder, wherein reinforcing fillers selected are carbon black, silica and combinations thereof, preferably carbon black - 0 - 60 phr and silica - 0-60 phr.

It is another aspect of the present invention to provide a tire tread rubber composition using eggshell powder, wherein the specific surface area of eggshell powder is lesser than the specific surface area of carbon black.

It is another aspect of the present invention to provide a tire tread rubber composition using eggshell powder, wherein the activators are selected from zinc oxide, stearic acid and combinations thereof, preferably zinc oxide -1.5-3.0 phr and stearic acid- 1.0 - 2.0 phr. It is another aspect of the present invention to provide a tire tread rubber composition using eggshell powder, wherein anti-degradants are selected from Microcrystalline wax (MC wax), N(l,3-dimethyl-butyl)-N’-phenylenediamine (6PPD) and combinations thereof, preferably MC wax- 1.0-4.0 phr and 6PPD - 1.5-4.5 phr.

It is another aspect of the present invention to provide a tire tread rubber composition using eggshell powder, wherein vulcanizing agent is sulphur - 1.3-2.5 phr.

It is another aspect of the present invention to provide a tire tread rubber composition using eggshell powder, wherein primary accelerators are selected N-Tertiarybutyl-2- benzothiazole sulfenamide - TBBS - 1.2-2.0 phr.

It is another aspect of the present invention is to provide a method for preparation of a tire tread rubber composition using eggshell powder, comprising of steps: preparation of master batch in two stages:

First stage as the mixing in the Banbury mixer head temperature maintained between 65 to 85 °C with rotor speed between 45 to 60 rpm; wherein the mixing chamber is charged with rubbers and allowed to mix for 0 to 50 seconds, wherein reinforcing fillers carbon black and silica are added along with eggshell powder as bio-filler and it is allowed to mix for the time period of 120 to 240 seconds and wherein process of silanization has been done with the reduced rotor speed of 20 to 35 rpm and further, rubber chemicals stearic acid, MC wax, process aid low PCA oil (except zinc oxide and 6PPD) are added and allowed it to mix for the time period of 120 to 300 seconds and sweeping done in the orifice and dumped at a temperature range of 140 °C to 160 °C and sheeted out in two roll mill. Second stage as, zinc oxide and 6PPD are added along with stage I master batch in the Banbury mixer and allowed to mix it for time period of 60 seconds to 180 seconds and dumped in the temperature range of 100°C to 150°C and sheeted out in the two roll mill.

Preparation of Final Batch:

Mixing of master batch rubber compound and curatives TBBS as primary accelerator and sulphur as vulcanizing agent are added and allowed it to mix for the time period of 60 to 100 seconds, dumped at temperature range of 110°C to 130°C, and sheeted out in two roll mill.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a tire tread rubber composition and its method of preparation. The eggshell powder contains greater than 90% of calcium carbonate and has traces of sulphur trioxide and silicon dioxide. Moreover, the specific surface area of eggshell powder is lesser than the specific surface area of carbon black. Thus, the eggshell powder used in this invention has lesser specific surface area than carbon black. Carbon black, reinforcing filler used for tyre tread has specific surface area is greater than 60 m ² /gm whereas specific surface area of the eggshell powder is less than 10 m ² /gm

Specific Surface area of the filler plays a vital role in filler dispersion. Carbon black and Silica reinforcing fillers are having high specific surface area and difficult to disperse in rubber matrix whereas the eggshell powder having very low specific surface area, gets well dispersed into rubber matrix and thereby it improves the polymer-filler interaction (bound rubber) rather than filler- filler interaction (filler networking). Hence, lower the specific surface area containing fillers provide better physico-mechanical properties. Hence, the eggshell powder is used as a bio-filler in SSBR: PBR diblend based tire tread rubber composition to improve wet grip and low rolling resistance properties.

The composition for tyre treads, comprises polymer matrix; eggshell powder as biofiller, carbon black and silica as reinforcing fillers; coupling agent; activators; antidegradants; vulcanizing agent; primary accelerators as mentioned in Table 1, Table 2 & Table 3.

The present invention relates to a tyre tread rubber composition for a tyre tread according to Table 1, Table 2 and Table 3 intended for the manufacture thereof. The rubber composition according to the invention comprises of: a. The tyre tread composition acccording to the present invention, which can be used for the manufacture of a tyre, comprising 100 parts by weight of a rubber(s), 65 parts by weight of a 37.5% oil extended solution styrene butadiene rubber with 25% of styrene content, 63% of vinyl content and Tg of -28°C. Also, 35 parts of another diene rubber used for the present invention is from the group consisting of the polybutadiene rubber, having greater than or equal to 96% high cis content. b. Reinforcing filler, Carbon Black SAF (Superior Abrasion Furnace) ASTM grade N 134, or any of the ASTM grades of Carbon Black having the Iodine adsorption No. 77 to 147 mg/gm, tinting strength value between 99 to 136 % ITRB and with the blend of another reinforcing inorganic filler silica having nitrogen surface area value ranges from 170 to 190 m ² /gm used for the present invention is to provide a 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. In the present invention, Egg shell powder used as a bio filler having surface area lesser than 10 m ² /gm used in the SSBR: PBR (65 phr:35 phr) blend based rubber composition is to provide a tyre tread having the essential characteristics combination of wet grip and LRR property. e. MES (Mild extracted solvate) oil or Low PCA oil is an environmentally friendly oil and is used to improve the processability of rubber compounds. f. The other ingredients selected for the present invention is based on the conventional motorcycle tyre tread composition antidegradant 6PPD is added to the rubber composition to provide resistance to thermo-oxidative ageing of elastomers and MC Wax to protect against degradation by ozone. g. 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. h. The vulcanization system used in the present invention is based on sulphur and on a primary accelerator TBBS.

Table I: Rubber Composition in Phr

Table 2: Rubber Compositions in phr Table 3: Rubber compositions in phr

1. SSBR- Solution styrene butadiene rubber (SOL C6270M) is 37.5 % oil extended SSBR having 23.5 to 26.5 % of bound styrene content, 60 to 66 % of vinyl content, raw Mooney viscosity value ranges from 46 to 56 and Tg of

28°C, from Kumho Petrochemical, Korea

2. PBR 1220 - High Cis Poly butadiene rubber from Reliance industries, India.

3. Egg Shell powder - It is a bio filler from Sri Annai Meenakshi Enterprises, Tamilnadu, No: 3/935/1, Pasiyapuram, Keeladi (po), Sivagangai district, Pin

630611, India. 4. Precipitated Silica - It is a reinforcing inorganic filler from Tata chemicals limited, India.

5. N 134 - ASTM carbon black grade having iodine surface area value ranges between 137 to 147 mg/gm, tinting strength value ranges between 126 to 136% ITRB from Birla carbon, India.

6. SI75 - It is a coupling agent from Nanjing shuguang silane Chemical Co., Ltd, India.

7. Zinc oxide - It is from POCL enterprises limited, India.

8. Stearic acid- It is from 3F industries limited, India.

9. MES oil - It is mild extracted solvate oil from GP Petroleums limited, India.

10. MC Wax - It is microcrystalline wax is an antiozonant from Gujarat Paraffins private limited, India.

11. 6PPD N-(l, 3-Dimethylbutyl)-N’-phenyl-p-phenylenediamine is an antidegradant from Nocil Limited, India.

12. TBBS - It is N- tert- butyl -2-benzothiazyl sulphenamide delayed action accelerator from Nocil Limited, India.

13. Sulphur - It is a vulcanizing agent from Southern minerals and chemicals, India.

Method of preparation of a tyre tread rubber composition:

Mixing Sequence:

Using a Banbury mixer with a tangential rotor, a rubber composition prepared by a thermo- mechanical process is as follows:

The method of preparation of the Rubber Composition includes the following:

Step I: Mixing has been done with the head temperature of the Banbury mixer maintained between 65 to 85°C and the unloaded rotor speed maintained between 45 to 60 rpm. The mixing cycle is to be followed as: a) Mixing chamber has been charged with rubbers and allowed to mix for 0 to 50 seconds b) process of silanization is carried out with reduced rotor speed of 20 to 30 rpm. c) and further, rubber chemicals low PCA oil, stearic acid, MC Wax (except zinc oxide and 6PPD), eggshell powder are added and allowed it to mix for time period of 120 to 240 seconds, d) sweeping has been done in the orifice and allowed it to mix for the time period of 120 to 300 seconds, the compound has been dumped at the temperature in the range of 140°C to 160°C and sheeted out in the laboratory two roll mill.

Step II: Add zinc oxide and 6PPD along with the step I master batch in the Lab Banbury Mixer and allowed to mix it for 60 seconds to 180 seconds and the compound has been dumped at the temperature in the range of 100°C to 150°C and sheeted out in the laboratory two roll mill.

Preparation of Final Batch:

Thermo-mechanical mixing in at least one preparatory mixing step - final batch is as follows:

Mixing chamber charged with the master batch rubber compound and the curatives TBBS as primary accelerator and sulphur as vulcanizing agent are allowed to mix for 60 to 100 seconds, and the compound has been dumped at the temperature range of 110°C to 130°C. The final batch sheet out has been done in the laboratory two roll mill.

Results:

Characterization of Cured Rubber Vulcanizate and Uncured Rubber Compound: Table 4: Properties of uncured Rubber Compound and Cured Rubber Vulcanizate

Table 5: Properties of uncured Rubber Compound and Cured Rubber Vulcanizate

Table 6: Properties of uncured Rubber Compound and Cured Rubber Vulcanizate

The compound properties are listed in Table 4, Table 5 & Table 6 as below:

The purpose of these tests is to measure the improved properties of the formulation related to the invention against control formulation as in Table 4. For this, SSBR: PBR blend (65 phr: 35 phr) based tyre tread rubber composition Fl reinforced by reinforcing fillers precipitated silica and carbon black grade N134 replaced by 20 phr of eggshell powder as a bio filler are prepared against SSBR: BR blend (65 phr: 35 phr) based tyre tread rubber composition reinforced by fillers carbon black grade N 134 and precipitated silica (C 1 Control) is prepared and evaluated.

The present invention provides a tyre tread rubber composition Fl, SSBR: PBR (65 phr: 35 phr) blend reinforced by reinforcing fillers precipitated silica and N134 carbon black replaced by 20 phr of eggshell powder as a bio filler gave ts value as 76.92 minutes i.e., process safety (Note: Ideal value of tyre tread rubber compound is 18 minutes) when compared to SSBR: PBR blend (65 phr: 35 phr) based tyre tread rubber composition reinforced by reinforcing fillers N134 and precipitated silica (Control, Cl) gave t5 value as 62.00 minutes.

Also, the present invention provides a tyre tread rubber composition Fl, SSBR: PBR (65 phr: 35 phr) blend reinforced by reinforcing fillers precipitated silica and N134 carbon black replaced by 20 phr of eggshell powder as a biofiller Mooney viscosity value lowered by 21% when compared to SSBR: PBR blend (65 phr: 35 phr) based tyre tread rubber composition reinforced by reinforcing fillers N 134 and precipitated silica (Control, Cl).

Also, the present invention provides a tyre tread rubber composition Fl, SSBR: PBR (65 phr: 35 phr) blend reinforced by reinforcing fillers precipitated silica and N134 carbon black replaced by 20 phr of eggshell powder as a biofiller rubber elasticity improved by 34.78% when compared to SSBR: PBR blend (65 phr: 35 phr) based tyre tread rubber composition reinforced by reinforcing fillers N 134 and precipitated silica (Control, Cl).

Morever, the present invention provides a tyre tread rubber compositions Fl, SSBR: PBR blend (65 phr: 35 phr) reinforced by reinforcing fillers precipitated silica and N134 carbon black is replaced by 20 phr of eggshell powder as a biofiller improved wet grip by 10.32% and rolling resistance lowered by 27.88% when compared to SSBR: PBR blend (65 phr: 35 phr) based tyre tread rubber composition reinforced by reinforcing fillers N134 and precipitated silica (Control, Cl).

The purpose of these tests is to measure the improved properties of the formulation related to the invention against control formulation as in Table 5. For this, SSBR: PBR blend (65 phr: 35 phr) based tyre tread rubber composition F2 reinforced by reinforcing fillers precipitated silica and carbon black grade N134 along with 20 phr of eggshell powder as a bio filler are prepared against SSBR: BR (65 phr: 35 phr) blend based tyre tread rubber composition reinforced by fillers carbon black grade N134 and precipitated silica (C2 Control) is prepared and evaluated.

The present invention provides a tyre tread rubber composition F2, SSBR: PBR (65 phr: 35 phr) blend reinforced by reinforcing fillers precipitated silica and N134 carbon black along with 20 phr of eggshell powder as a bio filler gave ts value as 73.42 minutes i.e., process safety (Note: Ideal value of tyre tread rubber compound is 18 minutes) when compared to SSBR: PBR blend (65 phr: 35 phr) based tyre tread rubber composition reinforced by reinforcing fillers N134 and precipitated silica (Control C2) gave t5 value as 58.03 minutes.

Also, the present invention provides a tyre tread rubber composition F2, SSBR: PBR (65 phr: 35 phr) blend reinforced by reinforcing fillers precipitated silica and N134 carbon black along with 20 phr of eggshell powder as a biofiller Mooney viscosity value lowered by 25.88% when compared to SSBR: PBR blend (65 phr: 35 phr) based tyre tread rubber composition reinforced by reinforcing fillers N134 and precipitated silica (Control, C2).

Also, the present invention provides a tyre tread rubber composition F2, SSBR: PBR (65 phr: 35 phr) blend reinforced by reinforcing fillers precipitated silica and N134 carbon black along with 20 phr of eggshell powder as a biofiller rubber elasticity improved by 31.72% when compared to SSBR: PBR blend (65 phr: 35 phr) based tyre tread rubber composition reinforced by reinforcing fillers N 134 and precipitated silica (Control C2). Morever, the present invention provides a tyre tread rubber compositions F2, SSBR: PBR blend (65 phr: 35 phr) reinforced by reinforcing fillers precipitated silica and N134 carbon black along with 20 phr of eggshell powder as a biofiller improved wet grip by 5.18% and rolling resistance lowered by 20.72% when compared to SSBR: PBR blend (65 phr: 35 phr) based tyre tread rubber composition reinforced by reinforcing fillers N134 and precipitated silica (Control, C2).

The purpose of these tests is to measure the improved properties of the formulation related to the invention against control formulation as in Table 6. For this, SSBR: PBR blend (65 phr: 35 phr) based tyre tread rubber composition F3 reinforced by reinforcing fillers precipitated silica and carbon black grade N134 replaced by 5 phr of eggshell powder as a bio filler are prepared against SSBR: BR blend (65 phr: 35 phr) based tyre tread rubber composition reinforced by fillers carbon black grade N134 and precipitated silica (C3 Control) is prepared and evaluated.

The present invention provides a tyre tread rubber composition F3, SSBR: PBR (65 phr: 35 phr) blend reinforced by reinforcing fillers precipitated silica and N134 carbon black replaced by 5 phr of eggshell powder as a bio filler gave ts value as 68.93 minutes i.e., process safety (Note: Ideal value of tyre tread rubber compound is 18 minutes) when compared to SSBR: PBR blend (65 phr: 35 phr) based tyre tread rubber composition reinforced by reinforcing fillers N134 and precipitated silica (Control, C3) gave t5 value as 61.65 minutes.

Also, the present invention provides a tyre tread rubber composition F3, SSBR: PBR (65 phr: 35 phr) blend reinforced by reinforcing fillers precipitated silica and N134 carbon black replaced by 5 phr of eggshell powder as a biofiller Mooney viscosity value lowered by 5.61% when compared to SSBR: PBR blend (65 phr: 35 phr) based tyre tread rubber composition reinforced by reinforcing fillers N 134 and precipitated silica (Control, C3) Also, the present invention provides a tyre tread rubber composition F3, SSBR: PBR (65 phr: 35 phr) blend reinforced by reinforcing fillers precipitated silica and N134 carbon black replaced by 5 phr of eggshell powder as a biofiller rubber elasticity improved by 2.19% when compared to SSBR: PBR blend (65 phr: 35 phr) based tyre tread rubber composition reinforced by reinforcing fillers N 134 and precipitated silica (Control, C3).

Morever, the present invention provides a tyre tread rubber compositions F3, SSBR: PBR blend (65 phr: 35 phr) reinforced by reinforcing fillers precipitated silica and N134 carbon black is replaced by 5 phr of eggshell powder as a biofiller provide comparable wet grip and rolling resistance lowered by 8.38% when compared to SSBR: PBR blend (65 phr: 35 phr) based tyre tread rubber composition reinforced by reinforcing fillers N134 and precipitated silica (Control, Cl).

Hence, the present invention provides a tyre tread rubber composition reinforced by reinforcing fillers carbon black grade N 134 and precipitated silica along with biofiller eggshell powder or eggshell powder replaced with carbon black provides high rubber elasticity, wet grip and lower rolling resistance property along with better processing properties. Also, the present invention tyre tread rubber composition is most suitable for motorcycle tyre.

Measurements and tests:

Ml. Better processability (Process Requirements) of a Rubber Compound:

Mooney Scorch Characteristics (pre vulcanization characteristics using large rotor) for processability:

The Mooney Scorch measurements are carried out with a Mooney Viscometer (MV 2000 Alpha technologies, USA) according to ASTM DI 646. MV- indicates Mooney viscosity in MU, ts indicates the time to scorch (MV+5) which indicates the processing properties (process safety).

M2. Rubber Elasticity of Rubber Vulcanizate Rebound Resilience % of Rubber vulcanizate are carried out as per ASTM D7121 in Rebound Resilience tester, Zwick Make Model 5109, Germany.

M3. Viscoelastic properties of the rubber vulcanizate:

The dynamic properties of the rubber vulcanizate are measured in a dynamic mechanical analyzer (DMA Metravib +1000) with a dynamic strain 0.3%, static strain: 6% and temperature sweep ranges from -40 to +80°C, frequency: 10Hz in tension mode as per ASTM D5992.

Tan delta at 0°C is commonly used as a predictor of tyre wet grip. Also, higher the tan delta value at 0°C, better the wet grip.

Tan delta at 60°C is commonly used as a predictor of tyre rolling resistance. Also, lower the tan delta value at 60°C, lower the rolling resistance.

In some aspects of the present disclosure, the composition includes polymer matrix as 100 parts per hundred (phr). The composition further includes eggshell powder ranging from 3-20 phr. The composition further includes reinforcing fillers ranging from 1-120 phr. The composition further includes coupling agent ranging from 1-6 phr. The composition further includes activators ranging from 1-5 phr. The composition further includes low polycyclic aromatics (PCA) oil ranging from 5-10 phr. The composition further includes anti-degradants ranging from 1-8.5 phr. The composition further includes vulcanizing agent ranging from 1.3-2.5 phr. The composition further includes primary accelerator ranging from 1.2-2 phr.

In some aspects of the present disclosure, the eggshell powder is a bio-filler in an (Solution-polymerized styrene -butadiene rubber : Polybutadiene Rubber) SSBR:PBR diblend contains 90% calcium carbonate and traces of sulphur trioxide and silicon dioxide.

In some aspects of the present disclosure, the polymer matrix is selected from the group comprising SSBR, PBR, and combinations preferably in a weight ratio of SSBR:PBR ranging from 35-65:65-35 phr. In some aspects of the present disclosure, the reinforcing fillers are selected from a group comprising carbon black, silica, and combinations preferably carbon black in the range of 0-60 phr and silica in a range of 0-60 phr.

In some aspects of the present disclosure, the specific surface area of the eggshell powder is lower than the specific surface area of carbon black.

In some aspects of the present disclosure, the activators are selected from a group comprising zinc oxide, stearic acid, and combinations preferably zinc oxide in the range of 1.5-3.0 phr and stearic acid in the range of 1.0-2.0 phr.

In some aspects of the present disclosure, the anti -degradants are selected from a group comprising Microcrystalline wax (MC wax), N(l,3-dimethyl-butyl)-N'- phenylenediamine (6PPD), and combinations thereof, preferably MC wax in the range of 1.0-4.0 phr and 6PPD in the range of 1.5-4.5 phr.

In some aspects of the present disclosure, the vulcanizing agent is sulfur in the range of 1.3-2.5 phr.

In some aspects of the present disclosure, the primary accelerators are selected from N-Tertiarybutyl-2-benzothiazole sulfenamide (TBBS) in the range of 1.2-2.0 phr.

In some aspect of the present disclosure, a method for preparation of a tire tread rubber composition using eggshell powder is provided.

In some aspects of the present disclosure, the method includes charging mixing chamber of a Banbury mixer with rubbers and allowing to mix for 0 to 50 seconds, by maintaining a head temperature between 65 to 85°C and a rotor speed between 45 to 60 rotations per minute (rpm). The method further includes adding reinforcing fillers, including carbon black and silica, along with eggshell powder as a bio-filler, and allowing to mix for a time period of 120 to 240 seconds such that silanization process is performed with a reduced rotor speed of 20 to 35 rpm. The method further includes additionally adding rubber chemicals such as stearic acid, MC wax, and low PCA oil (excluding zinc oxide and 6PPD) and mixed for a time period of 120 to 300 seconds, followed by sweeping the mixture from orifice and dumping at a temperature range of 140°C to 160°C and sheeting out the mixture by way of a two-roll mill. The method further includes adding zinc oxide and 6PPD to the sheeting mixture by way of a Banbury mixer and allowing to mix for a time period of 60 seconds to 180 seconds.

In some aspects of the present disclosure, the method further includes dumping the mixture at a temperature range of 100°C to 150°C and sheeting out by way of a two- roll mill. The method further includes adding curatives, the primary accelerator and vulcanizing agent to the mixture. The method further includes allowing to mix for a time period of 60 to 100 seconds. The method further includes dumping the mixture at a temperature range of 110°C to 130°C and sheeting it out using a two-roll mill.