WO2023152766A1

WO2023152766A1 - Tyre tread rubber composition using coconut shell powder and method thereof

Info

Publication number: WO2023152766A1
Application number: PCT/IN2023/050136
Authority: WO
Inventors: Sakthivel PREM SHANKAR; Arthi P.S; Kadambanathan THIAGARAJAN; Viswanathan Sivaramakrishnan
Original assignee: Tvs Srichakra Limited
Priority date: 2022-02-09
Filing date: 2023-02-09
Publication date: 2023-08-17

Abstract

The present invention relates to a high-performance motorcycle tyre tread rubber composition, with improved wet grip and its method of preparation. The green filler coconut shell powder as an additional filler in SSBR: BR blend tyre tread rubber composition containing carbon black and silica are reinforcing fillers provide better wet grip and dry grip along with better process safety. Moreover, the green filler coconut shell powder is replaced with the reinforcing filler carbon black in SSBR: BR blend-based tyre tread rubber composition is to provide better processability, high rubber elasticity, wet grip along with low rolling resistance.

Description

TYRE TREAD RUBBER COMPOSITION USING COCONUT SHEEE POWDER AND METHOD THEREOF

FIEED OF THE INVENTION

The present invention relates to the field of polymer technology. The present invention relates to the high-performance tyre tread rubber composition using coconut shell powder as a filler.

BACKGROUND OF THE INVENTION

As rubbers for a tire tread, rubbers having a high frictional force have been sought from the viewpoint of safety. On the other hand, a tire that has a small rolling resistance, that is, rubbers having a small hysteresis loss at the time of tire rolling have been sought from the viewpoint of the environment and health. Various proposals have been made to formulate a hard foreign substance or a hollow particle into a rubber to thereby form a micro irregularity on the surface of a rubber layer to provide better traction, but practically satisfactory results have not been obtained yet. These caused other problems such as increase in the hardness of the rubber and the loss of flexibility of the rubber whereby the resultant tire does not easily follow the contours of the road. Rubber compositions used for tyre treads are traditionally made with process oils to improve wet traction and, it enables processability.

Coconut (Coccus nucifera) is one the extensively grown food crops in the world. Every part of this tree is made in use. Further it generates huge amounts of waste material like coconut shell and skin. There has been limited efforts and applications discovered to find utilization of these materials. Filler/charcoal extracted from coconut shell has already been used as novel filler in Natural Rubber (NR) due to its chemical composition.

Reference made to the following patents/publications:

Publication No. EP0795582 relates to rubber mixture for tyre treads, especially for snow tyres, containing a fibre mixture consisting of cellulose fibres and keratin fibres in a wt. ratio of (1:5)- (5:1), preferably (3:7)-(2:l). Also claimed are tyres with treads consisting at least partly of. This patent discusses about the use of cellulose fibres and keratin fibres derived from animal, wood and coconut bristles in tread rubber composition whereas the present invention discusses about the use of coconut shell powder as filler in tyre tread rubber composition to provide better wet grip property. Coconut shell powder is totally different from coconut bristles. Publication No. US2016339744 relates to rubber compositions comprising at least one elastomer; reinforcing filler comprising carbon black, silica, or a combination thereof; at least one hydrocarbon resin; and at least one plant oil and optionally at least one additional oil, wherein the total amount of reinforcing filler is at least 25% by weight of the rubber composition and the total amount of oil is at least 60 phr and comprises about 15 to about 35% by weight of the rubber composition. The rubber compositions are useful in tire treads, particularly tire treads for race tires. In certain embodiments the at least one plant oil comprises coconut oil. This patent discusses about the use of triglyceride vegetable oil in tyre tread rubber composition has a tan 6 at 35° C of about 0.2 to about 0.8 whereas the present invention discusses about the use of coconut shell powder as a filler in tyre tread rubber composition to provide better wet grip property.

Publication No. KR20150029945 relates to a rubber composition for a tire tread, comprising 5-20 parts by weight of coconut tree powder for 100 parts by weight of raw rubber. More specifically, the present invention relates to a rubber composition for tire tread including 5-20 parts by weight of the coconut powder manufactured by peeling and drying rind of natural coconut trees and crushing the same into powder. This patent discusses about the use of palm flour as a filler in tyre tread rubber composition to provide wet grip whereas the present invention discusses about the use of coconut shell powder as a filler in tyre tread rubber composition to provide wet grip property.

Publication No. KR20120057078 relates to a rubber composition for tire tread to prevent sudden degradation of composition stability due to sudden deformation of rubber according to steering of a vehicle, to provide excellent tire strength, and to improve ice frictional coefficient remarkably. A rubber composition for tire tread comprises 100.0 parts by weight of crude rubber, 10-100 parts by weight of reinforcing filler, 1-8 parts by weight of a blowing agent, and 5-40 parts by weight of a coconut shell powder. A manufacturing method of the rubber composition for tire tread comprises: a step of manufacturing the coconut shell to pellet shape; a step of grinding the coconut shell; and a step of manufacturing the rubber composition by mixing the coconut shell powder, the reinforcing filler, the blowing agent, and other additives. This patent discusses about the manufacturing method of coconut husk grind to pellet shape and it is used as a filler in NR: BR blend based tyre tread rubber composition to provide better coefficient of friction whereas the present invention discusses about the use of coconut shell powder as a filler in SSBR: BR blend based tyre tread rubber composition to provide better wet grip property.

IN Publication No. 201921015284 relates to a rubber formulation with bio-based plasticizer comprising essentially of coconut shell oil (CSO), optionally with a bifunctional, sulfur- containing organosilane in combination with white fillers containing silanol groups as a coupling agent 0.1 to 50 weight percentage directly mixed or pre-mixed to the CSO. Further, it discloses a method of preparing a rubber formulation with bio-based plasticizer comprising the steps of distillation of grounded coconut shell followed by pyrolysis, wherein the step of distillation is carried out with grounded coconut shells in controlled temperature; and premixing or direct mixing of coupling agent to the extract yielded from the previous step followed by drying at 50-200 °C, preferably 100 °C for 2-6 hours, wherein the pyrolysis is carried out by heating the shells at 200-1200 °C for 0.5 to 5 hours followed by condensing in a condenser attached to the flask. This patent discusses about the use of coconut shell oil obtained by pyrolysis of grounded coconut shell as a plasticizer along with sulfur containing organosilane in combination with white fillers containing silanol groups whereas the present invention discusses about the use of coconut shell powder as filler in tire tread rubber composition to provide wet grip property.

Publication No. GB934628 relates to coating compositions suitable for application to floors, decks and the like are made by treating a raw filler material with an organic silicate or an incompletely polymerized polymer thereof, and subsequently mixing the so-treated filler with a liquid cross-linkable resin binder. A cross-linking agent for the binder may be mixed with the composition immediately prior to application, which may be by a trowel or float. Fillers mentioned include sand, quartz, Tripoli, diatomite, asbestos, carbon black, coke, charcoal, wood flour and cork and ground coconut shell. This patent discusses about the use of coating composition containing any one filler material of sand, quartz, Tripoli, diatomite, asbestos, carbon black, coke, charcoal, wood flour and cork and ground coconut shell along with crosslinkable resin binder whereas the present invention discusses about the use of coconut shell powder as a filler in SSBR: BR blend based tyre tread rubber composition to provide wet grip property.

Publication No. US2011028257 relates to a rubber composition having a reinforcing filler of activated carbon having a pore volume of 0.15 cc/g or more, a weight average particle size of less than 140 microns, and a differential characteristic curve of pore volume versus adsorption potential by the GAED or equivalent method having a peak value at less than 5 cal/cc. The rubber composition may have activated carbon as the primary reinforcing filler at a loading of from 25 to 250 phr. Also described is a method including the steps of selecting a charcoal material, grinding the charcoal material, activating the charcoal material, and mixing the activated carbon into a rubber composition as the primary reinforcing filler. This patent discusses about the use of rubber composition containing 25 to 250 phr of loading of activated carbon as primary reinforcing filler having less than 140 microns particle size whereas the present invention discusses about the use of coconut shell powder as a filler in tyre tread rubber composition to provide wet grip property.

The article entitled “Utilization of coconut shell powder as a novel filler in natural rubber” by C Sareena; MT Ramesan; E Purushothaman; Department of Chemistry, University of Calicut, Kerala, India; Journal of Reinforced Plastics and Composites; Volume: 31 issue: 8, page(s): 533-547; March 1, 2012 talks about the use of coconut shell powder as filler in natural rubber. Coconut, one of the food crops in the world, generates large amounts of waste material namely coconut shell. Modified and unmodified coconut shell powder-natural rubber composites with varying particle size and dosages were prepared by an open mill-mixing technique. The processing characteristics and the curing behavior of the composites were determined by Monsanto Rheometer. The technological performance was done by analyzing the tensile strength, tear strength and hardness of the vulcanizate. The swelling studies were carried out to observe the crosslink density and the reinforcement ability of the filler on natural rubber. The observed variation in mechanical properties has been supported by the fractography of the composites obtained by scanning electron microscopy. The results of the study show that the coconut shell powder is most effective filler in natural rubber at 10 parts per hundred loading. Reinforcement ability of modified coconut shell powder is more when compared to unmodified coconut shell powder, therefore modified coconut shell powder-natural rubber composites show better physicomechanical properties. This article discusses about the incorporation of coconut shell powder into natural rubber matrix which enhances the thermal properties of the natural rubber — coconut shell powder composites whereas the present invention discusses about the use of coconut shell powder as a filler in SSBR:BR blend based tire tread rubber composition to provide wet grip property. The article entitled “Coconut shell powder as cost effective filler in copolymer of acrylonitrile and butadiene rubber” by B Keerthika, M Umayavalli, T Jeyalalitha, N Krishnaveni; Ecotoxicol Environ Saf; 2016 Apr 6 talks about filler which is one of the major additives in rubber compounds to enhance the physical properties. Even though numerous benefits obtained from agricultural by products like coconut shell, rice husk etc., still they constitute a large source of environmental pollution. In this investigation, one of the agricultural bye product coconut shell powder (CSP) is used as filler in the compounding KNB rubber. It shows the positive and satisfied result was achieved only by the use of filler Fast Extrusion Furnace (FEF) and coconut shell powder (CSP) which was used 50% in each. The effect of these fillers on the mechanical properties of a rubber material at various loading ranging from 0 to 60PHP was studied. Mercaptodibanzothiazole disulphide (MBTS) was used as an accelerator. The result shows that presence of 25% and 50% of the composites has better mechanical properties like Hardness, Tensile strength, Elongation at break and Specific gravity when compared with other two combinations. Even though both 25% and 50% of composites shows good mechanical properties, 50% of CSP have more efficient than 25% of CSP whereas the present invention discusses about use of coconut shell powder as a filler in SSBR:BR blend based tire tread rubber composition to provide wet grip property.

Hence there needed an improved composition with improved wet grip and dry grip property.

In order to overcome above listed prior art, the present invention aims to provide a high performance motorcycle tyre tread rubber composition, with improved wet and dry grip and its method of preparation.

OBJECT OF THE INVENTION

The principal object of the present invention is to provide a high performance motorcycle tyre tread rubber composition with improved wet grip along with dry grip.

Yet another object of the present invention is to provide a high performance motorcycle tyre tread composition with improved wet along with lower rolling resistance. Yet another object of present invention is a partial replacement of conventional fillers like carbon black with coconut shell powder or by addition of coconut shell powder as a natural filler along with conventional fillers as a natural filler in tire tread rubber composition.

Another object of the present invention is to provide a natural filler to provide green tyre tread rubber composition.

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 primary aspect of the present invention to provide a tyre tread rubber composition, comprising of:

Polymer matrix - 100 parts;

Natural filler - 1-20 parts;

Reinforcing fillers - 0 - 100 phr;

Coupling agent - 0.8 - 4 phr;

Activators - 1.5 - 8 phr;

Process aid - 4-10 phr;

Antidegradants - 0-7 phr;

Vulcanization agent - 1.5 - 3 phr; anda

Accelerator -1.0 -2.5 phr, wherein the natural filler is selected from coconut shell powder.

It is another aspect of the present invention to provide the tyre tread rubber composition, wherein the coconut shell powder has greater than 25% of lignin content and greater than 18% of pentosans. It is another aspect of the present invention to provide the tyre tread rubber composition, wherein the coconut shell powder has elemental weight percentage carbon content of 65%, oxygen content of 32.59% and silicon 1.66%.

It is another aspect of the present invention to provide the tyre tread rubber composition, wherein the polymer matrix consists of polymer selected from Solution styrene butadiene rubber (SSBR), Butadiene rubber (BR) and combinations thereof, preferably SSBR: 50-90 phr and BR: 10-50 phr.

It is another aspect of the present invention to provide the tyre tread rubber composition, wherein the reinforcing fillers are carbon black, silica, and combinations thereof, preferably carbon black: 20-60 phr, and silica: 0-40 phr.

It is another aspect of the present invention to provide the tyre tread rubber composition, wherein the coupling agent is silane Si75 - 0.8-4 phr.

It is another aspect of the present invention to provide the tyre tread rubber composition, wherein the activators are selected from zinc oxide, stearic acid, and combinations thereof, preferably zinc oxide: 2-5 phr, and stearic acid: 1.3-3 phr.

It is another aspect of the present invention to provide the tyre tread rubber composition, wherein the process aid is TDAE (Treated distillate aromatic extracts) oil: 4-10 phr.

It is another aspect of the present invention to provide the tyre tread rubber composition, wherein the anti-oxidants are selected from poly(l,2-dihydro-2,2,4-trimethyl-quinoline) [TMQ], N(l,3-dimethyl-butyl)-N’phenyl-p-phenyldiamine [6PPD], Microcrystalline wax, an antiozonant and combinations thereof, preferably TMQ: 1-2.5 phr, 6PPD- 1-2.5 phr and MC wax: 0-2 phr.

It is another aspect of the present invention to provide a tyre tread rubber composition, wherein the vulcanization agent is sulphur: 1.5-3 phr.

It is another aspect of the present invention to provide a tyre tread rubber composition, wherein the accelerator is selected from N-Cyclohexyl-2-benzothiazole sulfenamide: 1-2.5 phr. It is another aspect of the present invention to provide a method for preparation of tyre tread rubber composition comprising of steps: preparation of master batch: step 1: mixing of rubber for 0-40 seconds with the head temperature of the Banbury maintained between 65 and 80 degree Celsius and the unloaded rotor speed maintained between 50 to 60 rpm and further reinforcing fillers coconut shell powder and silica, coupling agent Si75 are added and allowed it to mix upto 125° C, silanization process carried out for 60 seconds at 20-25 rpm, further reinforcing filler carbon black, TDAE oil, Stearic acid, TMQ, MC wax are mixed for 90-200 seconds at 50-60 rpm, sweeping down in the orifice and mixing for 90-102 seconds and dumping at temperature in the range of 140 to 170 degree Celsius and sheet out, wherein the rubber composition comprises of filler selected from coconut shell powder having greater than 25% of lignin content and greater than 18% of pentosans, step 2: mixing of step 1 master batch, zinc oxide and 6PPD for 60-180 seconds, and dumping at a temperature range of 110 to 125 °C and sheet out; and

Preparation of final batch: mixing of master batch compound and curatives for 60 - 90 seconds, dumping at a temperature range of 100- 120°C and sheet out.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 represents SEM (Scanning electron microscope) image at 20pm magnification of the green filler coconut shell powder; and

Figure 2 represents the TEM (Transition electron microscopy) image at 200 nm magnification of the green filler coconut shell powder. DETAILED DESCRIPTION OF THE INVENTION

At the outset of the description that follows, it is to be understood that the ensuing description only illustrates a particular form of this invention. However, such a particular form is only an exemplary embodiment and is not intended to be taken restrictively to imply any limitation on the scope of the present invention.

Source and geographical origin of biological material used in the present invention:

Coconut shell powder is obtained from matured coconut shells. It is obtained from Saras wathi Traders & Exporters, S.F. No :2/152d Pallakad Main Road, Zamin Muthur, Pollachi 642005, Tamilnadu.

The present invention relates to a high-performance motorcycle tyre tread rubber composition, with improved wet grip and its method of preparation. The coconut shell powder is used as filler in the tyre tread rubber composition for better reinforcement. The coconut shell powder as a filler in SSBR: BR blend-based tyre tread rubber composition to provide better wet grip property along with better dry grip.

The composition for motorcycle tyre treads comprises polymer matrix; coconut shell powder as a reinforcing green filler (Natural filler), carbon black and silica; coupling agent; activators; anti-degradants; vulcanization agent; primary accelerator.

The present invention relates to a high performance motor cycle green tyre tread composition 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 solution styrene butadienerubber and it is 37.5% TDAE oil extended solution styrene butadiene rubber (SSBR) with 32.5 to 35.50 % of styrene content, 55% to 61% of vinyl content and Tg of -24°C with raw rubber Mooney viscosity 65 to 70 MU at 120 deg C, and polybutadiene rubber with raw rubber mooney viscosity at ML (1+4) @ 100°C is 45 MU. b) Reinforcing filler, ASTM grades of carbon black having the Iodine adsorption No. 115 to 125 mg/gm, tinting strength value ranges between to 118 to 127 % ITRB 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) 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) Coconut Shell Powder - It is a reinforcing green filler. Coconut shell powder is obtained from matured coconut shells. The elemental weight percentage of coconut shell powder in elemental analysis measured through SEM ED AX is having Carbon - 65%, Oxygen - 32.59% and Silicon -1.66% e) TDAE (Treated distillate aromatic extracts) is a rubber processing oil (a natural friendly oil) with a high aromatic content, environmental protection, non-toxic, non- carcinogenic characteristics. It is used in the present invention to produce a high performance motorcycle green tyre tread composition. f) 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 an antioxidant TMQ is added to the rubber composition to provide resistance to thermo-oxidative ageing of elastomers. 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 a primary accelerator CBS.

Table 1: Rubber Composition in Phr

Table 2: Rubber Compositions in Phr

1. SSBR 6361H is 37.5% TDAE oil extended solution styrene butadiene rubber (SSBR) with 32.5 to 35.50 % of styrene content, 55% to 61% of vinyl content and Tg of -24 °C with raw rubber Mooney viscosity 65 to 70 MU at 120 deg C from Kurnho Petrochemical Group, Korea.

2. PBR 1220 - It is from Reliance Industries Ltd, India with the Mooney viscosity, ML (1+4) @ 100°C is 45 MU

3. Carbon Black N234 - It is from Continental Carbon, India. It is the ASTM Grade, reinforcing filler ISAF, Intermediate Superior Abrasion Furnace having the Iodine adsorption No. 115 to 125 mg/gm, tinting strength value ranges between to 118 to 127 % ITRB.

4. 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

5. Coconut Shell Powder - It is from Saraswathi Traders and Exporters, Pollachi Tamilnadu India. Elemental anlaysis done through SEM (Scanning electron microscope) EDAX (Energy-dispersive X-ray analysis) is a technique used to provide elemental identification and quantitative compositional information. Such technique is used to identify the coconut shell powder elemental composition. The elemental weight percentage of coconut shell powder in elemental analysis having Carbon - 65%, Oxygen -32.59% and Silicon -1.66%

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-(l,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine) It is an antidegradant (antioxidant and antiozonant) from Nocil Limited, India.

11. TMQ- 2, 2, 4 - trimethyl 1-1, 2-dihydroquinoline (Oligomers). It is an antioxidant from Nocil Limited, India.

12. TDAE Oil - Treated distillate aromatic extracts (TDAE) is a rubber processing oil from Indian Oil Corporation Limited, India

13. Sulphur- It is a vulcanizing agent from The Standard Chemical Co. Pvt Ltd, India.

14. CBS- N-cyclohexyl-2-benzothiazolesulfenamide) from Nocil Limited, India. It is a delayed action accelerator suitable for diene rubbers.

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

Preparation of master batch:

Step I: Mixing has been done with the head temperature of the Banbury maintained between 65 to 80°C and the unloaded rotor speed maintained between 50 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 40 seconds b) and further reinforcing fillers coconut shell powder and silica, coupling agent Si75 are added and allowed it to mix upto 125° C, silanization process done for 60 seconds at 20 to 25 rpm , further reinforcing filler carbon black, TDAE oil, Stearic acid, TMQ, MC wax are added and allowed to mix for 90-200 seconds at 50-60 rpm, c) sweeping has been done in the orifice and allowed to mix for another 90 to 102 seconds, the compound has been dumped at the temperature in the range of 140 °C to 170°C and sheeted out in the laboratory two roll mill.

Step II: Add the step I master batch, Zinc oxide and 6PPD in the Lab Banbury Mixer and mix it for 60 seconds to 180 seconds and the compound has been dumped at the temperature in the range of 110°C to 125°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, and allowed to mix for 60 to 90 seconds and the compound has been dumped at the temperature in the range of up to the temperature 100°C to 120°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:

The Compound Properties are listed in Table 3 and Table 4:

Table 3: Characterization of Cured Rubber Vulcanizate and Uncured Rubber Compound

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

Results

Measurements and tests (Table 3 & 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, nine compositions namely Cl, Fl-I, Fl-II, Fl-III, Fl-IV & F2, F2-I, F2-II, F2-III, F2-IV are prepared based on SSBR: PBR (60 phr : 40 phr) blend based motorcycle tyre tread rubber composition reinforced by carbon black and silica as reinforcing fillers containing green filler coconut shell powder as an additional filler/ or replacement with reinforcing filler carbon black (Fl -I, Fl-II, Fl-III, Fl-IV & F2, F2-I, F2-II , F2-III, F2-IV) against SSBR: PBR (60 phr: 40 phr) blend based motorcycle tyre tread rubber composition reinforced by carbon black and silica as fillers without using green filler coconut shell powder (Cl Control composition) are prepared and evaluated.

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, four compositions namely Fl-I, Fl-II, Fl-III, Fl-IV are prepared based on SSBR: PBR (60 phr : 40 phr) blend based motorcycle tyre tread rubber composition reinforced by carbon black and silica as reinforcing fillers containing green filler coconut shell powder as an additional filler along with reinforcing fillers carbon black and silica (Fl -I, Fl-II, Fl-III, Fl-IV) against SSBR: PBR (60 phr: 40 phr) blend based motorcycle tyre tread rubber composition reinforced by carbon black and silica as fillers without using green filler coconut shell powder (Cl Control composition) are prepared and evaluated.

The present invention provides a 100 parts by weight of rubber compositions namely Fl-1, Fl-II, Fl-III, Fl-IV are SSBR: PBR (60 phr: 40 phr) blend based rubber compositions containing green filler coconut shell powder as an additional filler in the weight proportion of 3 phr, 9 phr, 17 phr and 20 phr gave better processing characteristics i.e., t5 value improved by 1.02 % to 20.96 % when compared to SSBR: PBR (60 phr : 40 phr) blend based motor cycle tyre tread rubber compositions reinforced by carbon black and silica as fillers without using green filler coconut shell powder (Cl Control composition). Note: Ideal value of tread compound for better processability is greater than or equal to 18 minutes.

Moreover, the present invention provides a 100 parts by weight of rubber compositions namely Fl-1, Fl-II, Fl-III, Fl-IV SSBR: PBR (60 phr: 40 phr) blend based rubber compositions containing green filler coconut shell powder as an additional filler in the weight proportion of 3 phr, 9 phr, 17 phr and 20 phr gave hardness value ranges from 60 to 63 Shore A when compared to SSBR: PBR (60 phr : 40 phr) blend based motor cycle tyre tread rubber compositions reinforced by carbon black and silica as fillers without using green filler coconut shell powder (Cl Control composition).

The present invention provides a 100 parts by weight of rubber compositions namely Fl-1, Fl-II, Fl-III, Fl-IV are SSBR: PBR (60 phr: 40 phr) blend based rubber compositions containing green filler coconut shell powder as an additional filler in the weight proportion of 3 phr, 9 phr, 17 phr and 20 phr gave higher wet grip 3.80 % to 11.47% when compared to SSBR: PBR (60 phr : 40 phr) blend based motor cycle tyre tread rubber compositions reinforced by carbon black and silica as fillers without using green filler coconut shell powder (Cl Control Composition).

The present invention provides a 100 parts by weight of rubber compositions namely Fl-1, Fl-II, Fl-III, Fl-IV are SSBR: PBR (60 phr: 40 phr) blend based rubber compositions containing green filler coconut shell powder as an additional filler in the weight proportion of 3 phr, 9 phr, 17 phr and 20 phr gave higher dry grip 0.23 % to 7.58% when compared to SSBR: PBR (60 phr : 40 phr) blend based motor cycle tyre tread rubber compositions reinforced by carbon black and silica as fillers without using green filler coconut shell powder (Cl Control composition).

Overall, the present invention provides a 100 parts by weight of rubber compositions namely Fl-1, Fl-II, Fl-III, F1-1V are SSBR: PBR (60 phr: 40 phr) blend based rubber compositions containing green filler coconut shell powder as an additional filler in the weight proportion ranging from 3 to 20 phr provides wet and dry grip along with process safety. Also, 100 parts by weight of rubber compositions Fl-1, Fl-II, Fl-III, F1-1V are SSBR: PBR (60 phr: 40 phr) blend based rubber compositions containing green filler coconut shell powder as an additional filler in the weight proportion ranging from 3 to 20 phr having hardness ranging from 60 Shore A to 63 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, four compositions namely F2, F2-I, F2-II , F2-III, F2-IV are prepared based on SSBR: PBR (60 phr : 40 phr) blend based motorcycle tyre tread rubber composition reinforced by carbon black and silica as reinforcing fillers containing green filler coconut shell powder is replaced with reinforcing filler carbon black (F2, F2-I, F2-II , F2-III, F2-IV) against SSBR: PBR (60 phr: 40 phr) blend based motorcycle tyre tread rubber composition reinforced by carbon black and silica as fillers without using green filler coconut shell powder (Cl Control Composition) are prepared and evaluated.

The present invention provides a 100 parts by weight of rubber compositions namely Fl-1, Fl-II, Fl-III, F1-1V are SSBR: PBR (60 phr: 40 phr) blend based rubber compositions containing green filler coconut shell powder is replaced in the weight proportion of 3 phr, 9 phr, 17 phr and 20 phr with the reinforcing filler carbon black gave better processing characteristics i.e., t5 value improved by 1.60 % to 39.41 % when compared to SSBR: PBR (60 phr : 40 phr) blend based motor cycle tyre tread rubber compositions reinforced by carbon black and silica as fillers without using green filler coconut shell powder (Cl Control Composition). Note: Ideal value of tread compound for better processability is greater than or equal to 18 minutes.

Moreover, the present invention provides a 100 parts by weight of rubber compositions namely Fl-1, Fl-II, Fl-III, F1-1V are SSBR: PBR (60 phr: 40 phr) blend based rubber compositions containing green filler coconut shell powder is replaced in the weight proportion of 3 phr, 9 phr, 17 phr and 20 phr with the reinforcing filler carbon black gave hardness value ranges from 54 to 59 Shore A when compared to SSBR: PBR (60 phr : 40 phr) blend based motor cycle tyre tread rubber compositions reinforced by carbon black and silica as fillers without using green filler coconut shell powder (Cl Control Composition).

Moreover, the present invention provides a 100 parts by weight of rubber compositions namely Fl-1, Fl-II, Fl-III, F1-1V are SSBR: PBR (60 phr: 40 phr) blend based rubber compositions containing green filler coconut shell powder is replaced in the weight proportion of 3 phr, 9 phr, 17 phr and 20 phr with the reinforcing filler carbon black gave higher rubber elasticity ranges from comparable to 22.29 % when compared to SSBR: PBR (60 phr : 40 phr) blend based motor cycle tyre tread rubber compositions reinforced by carbon black and silica as fillers without using green filler coconut shell powder (Cl Control Composition).

The present invention provides a 100 parts by weight of rubber compositions namely Fl-1, Fl-II, Fl-III, F1-1V are SSBR: PBR (60 phr: 40 phr) blend based rubber compositions containing green filler coconut shell powder is replaced in the weight proportion of 3 phr, 9 phr, 17 phr and 20 phr with the reinforcing filler carbon black gave higher wet grip 3.70 % to 20.63 % when compared to SSBR: PBR (60 phr : 40 phr) blend based motor cycle tyre tread rubber compositions reinforced by carbon black and silica as fillers without using green filler coconut shell powder (Cl Control composition).

The present invention provides a 100 parts by weight of rubber composition Fl-1, Fl-II, Fl- III, F1-1V SSBR: PBR (60 phr: 40 phr) blend based rubber compositions containing green filler coconut shell powder is replaced in the weight proportion of 3 phr, 9 phr, 17 phr and 20 phr with the reinforcing filler carbon black gave lower rolling resistance ranging from 1.03 % to 16.79% when compared to SSBR: PBR (60 phr : 40 phr) blend based motor cycle tyre tread rubber compositions reinforced by carbon black and silica as fillers without using green filler coconut shell powder (Cl Control composition). Overall, the present invention provides a 100 parts by weight of rubber compositions namely Fl-1, Fl-II, Fl-III, F1-1V are SSBR: PBR (60 phr: 40 phr) blend based rubber compositions containing green filler coconut shell powder is in the weight proportion ranging from 3 to 20 phr provides better process safety, wet grip along with lower rolling resistance. Also, 100 parts by weight of rubber compositions namely Fl-1, Fl-II, Fl-III, F1-1V are SSBR: PBR (60 phr: 40 phr) blend based rubber compositions containing green filler coconut shell powder replaced in the weight proportion of 3 to 20 phr having hardness ranging from 54 Shore A to 59 Shore A.

Measurements and Tests:

Better processability (Process Requirements) of a Rubber Compound:

Ml. 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) ts 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: 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.

M4. 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 to 80 °C, Dynamic strain: 0.3%, Static strain:0.6%, Frequency: 10 Hz. tan delta at 0°C is a predictor for wet grip and tan delta at 25 deg C is a predictor for dry grip. Also, tan delta at 60°C is a predictor for rolling resistance (Lower tan delta value at 60 °C is good for LRR property). Coconut shell powder contains greater than 25% of lignin content and greater than 18% of pentosans. Therefore, the presence of coconut shell powder in motorcycle tire tread compound improves the wet grip and dry grip property.

Claims

WE CLAIM:

1. A tyre tread rubber composition, comprising of:

Polymer matrix - 100 parts;

Natural filler - 1-20 parts;

Reinforcing fillers - 0 - 100 phr;

Coupling agent - 0.8 - 4 phr;

Activators - 1.5 - 8 phr;

Process aid - 4-10 phr;

Antidegradants- 0-7 phr;

Vulcanization agent - 1.5 - 3 phr; and

2. The tyre tread rubber composition as claimed in claim 1, wherein the coconut shell powder has greater than 25% of lignin content and greater than 18% of pentosans.

3. The tyre tread rubber composition as claimed in claim 1, wherein the coconut shell powder has elemental weight percentage carbon content of 65%, oxygen content of 32.59% and silicon 1.66%.

4. The tyre tread rubber composition as claimed in claim 1 , wherein the polymer matrix consists of polymer selected from Solution styrene butadiene rubber (SSBR), Butadiene rubber (BR) and combinations thereof, preferably SSBR: 50-90 phr and BR: 10-50 phr.

5. The tyre tread rubber composition as claimed in claim 1, wherein the reinforcing fillers are carbon black, silica, and combinations thereof, preferably carbon black: 20-60 phr, and silica: 0-40 phr.

6. The tyre tread rubber composition as claimed in claim 1, wherein the coupling agent is silane Si75 - 0.8-4 phr.

7. The tyre tread rubber composition as claimed in claim 1, wherein the activators are selected from zinc oxide, stearic acid, and combinations thereof, preferably zinc oxide: 2-5 phr, and stearic acid: 1.3-3 phr.

8. The tyre tread rubber composition as claimed in claim 1, wherein the process aid is TDAE (Treated distillate aromatic extracts) oil: 4-10 phr.

9. The tyre tread rubber composition as claimed in claim 1, wherein the anti-degradants are selected from poly(l,2-dihydro-2,2,4-trimethyl-quinoline) [TMQ], N(l,3-dimethyl-butyl)- N’phenyl-p-phenyldiamine [6PPD], Microcrystalline wax, an antiozonant and combinations thereof, preferably TMQ: 1-2.5 phr, 6PPD- 1-2.5 phr and MC wax: 0-2 phr.

10. The tyre tread rubber composition as claimed in claim 1, wherein the vulcanization agent is sulphur: 1.5-3 phr.

11. The tyre tread rubber composition as claimed in claim 1, wherein the accelerator is selected from N-Cyclohexyl-2-benzothiazole sulfenamide: 1-2.5 phr.

12. A method for preparation of tyre tread rubber composition, comprising of steps: preparation of master batch: step 1: mixing of rubber for 0-40 seconds with the head temperature of the Banbury maintained between 65 and 80 degree Celsius and the unloaded rotor speed maintained between 50 to 60 rpm and further reinforcing fillers coconut shell powder and silica, coupling agent Si75 are added and allowed it to mix upto 125° C, silanization process carried out for 60 seconds at 20-25 rpm, further reinforcing filler carbon black, TDAE oil, Stearic acid, TMQ, MC wax are mixed for 90-200 seconds at 50-60 rpm, sweeping down in the orifice and mixing for 90-102 seconds and dumping at temperature in the range of 140 to 170 degree Celsius and sheet out, wherein the rubber composition comprises of filler selected from coconut shell powder having greater than 25% of lignin content and greater than 18% of pentosans, step 2: mixing of step 1 master batch, zinc oxide and 6PPD for 60-180 seconds, and dumping at a temperature range of 110 to 125 °C and sheet out; and