EP4688459A1

EP4688459A1 - Improved tyre tread composition comprising niger seed oil

Info

Publication number: EP4688459A1
Application number: EP24723229.1A
Authority: EP
Inventors: Tanumoy DAS; Antara Mondal; Jyoti Prakash RATH
Original assignee: Apollo Tyres Ltd
Current assignee: Apollo Tyres Ltd
Priority date: 2023-03-30
Filing date: 2024-03-27
Publication date: 2026-02-11
Also published as: WO2024201518A1

Abstract

The present invention provides a tyre tread composition comprising at least a diene rubber, reinforcing fillers, niger seed oil as a vegetable-based sustainable process oil, and optionally silanes. The niger seed oil at particular loading dosages improves the cut and tear performance, and abrasion resistance of the tyre tread composition.

Description

IMPROVED TYRE TREAD COMPOSITION COMPRISING NIGER SEED OIL

FIELD OF THE INVENTION

The present invention relates to the field of rubber technology. In particular, a tyre tread composition comprising bio-based process oil as a sustainable substitute is used.

BACKGROUND OF THE INVENTION

This section is intended to provide information relating to the field of the invention and thus, any approach or functionality described below should not be assumed to be qualified as prior art merely by its inclusion in this section.

Climate change has become a major concern for over the last decade and sustainability of tyres has been a critical issue in the tyre industry. Process oil is used in tyre compounding for improvement in processability. Tyre tread compositions comprise polymers, reinforcing fillers, process oil, and curatives. The mechanical properties, abrasion resistance properties of the tyre composition depend upon the reinforcement index of the reinforcing filler. However, the incorporation of high filler loading simultaneously requires the addition of plasticizers or oils such as petroleum-based oils to improve filler dispersion and reduce compound viscosity for easier processing. Plasticizers soften the compound by providing lubrication between rubber molecules and, thus, promote filler incorporation and dispersion during mixing. Amongst petroleum-based oils, usage of aromatic process oil in tyre industries is very popular to improve the filler dispersion and processability of the rubber compounds. However, aromatic oils have relatively high content of polycyclic aromatic hydrocarbons (PAHs) and many of these PAHs have been identified or suspected as carcinogens having toxic effects on organisms of human and environment.

Conventional approach is to replace aromatic oil by low-PAHs petroleum-based oils. Although, low-PAHs petroleum-based oils such as RAE, TDAE oils have been used as substitutes, it has been revealed that some petroleum-based oils also contain carcinogens. Apart from that, the feedstock for these oils also remain the same, i.e., petroleum based non-sustainable feedstock. Another approach involves the use of resins as process aid, but resins increase the hysteresis loss at 70°C.

There remains an unmet need to develop a tyre tread composition comprising non-carcinogenic process oils that increases the sustainability of the tyre and in turn provides enhanced mileage and beter performance to the tyres by improving the abrasion resistance, and cut and tear resistance of the tyres.

SUMMARY OF THE INVENTION

This section is intended to introduce certain aspects of the disclosed method in a simplified form and is not intended to identify the key advantages or features of the present disclosure.

In an aspect of the present invention, there is provided a tyre tread composition comprising (a) at least a diene rubber selected from the group consisting of at least a natural rubber, at least a synthetic rubber, and combinations thereof; (b) at least a reinforcing filler selected from the group consisting of carbon black, silica, and combinations thereof; and (c) niger seed oil characterized in that the niger seed oil comprises linoleic acid having concentration of at least 70% of total faty acids.

In another aspect of the present invention, there is provided a tyre comprising a tyre tread composition comprising (a) at least a diene rubber selected from the group consisting of at least a natural rubber, at least a synthetic rubber, and combinations thereof; (b) at least a reinforcing filler selected from the group consisting of carbon black, silica, and combinations thereof; and (c) niger seed oil characterized in that the niger seed oil comprises linoleic acid having concentration of at least 70% of total faty acids.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, for the purposes of explanation, various specific details are set forth in order to provide a thorough understanding of the embodiments of the present invention. It will be apparent, however, that the embodiments of the present invention may be practiced without these specific details. Several features described hereafter can each be used independently of one another or with any combination of other features. An individual feature may address only one of the problems discussed above. Some of the problems discussed above might not be fully addressed by any of the features described herein.

Definitions:

The following acronyms are used in the present description.

“CB” refers to Carbon Black;

“RRc” refers to Rolling Resistance Coefficient;

“NR” refers to natural rubber;

“SR” refers to synthetic rubber,

“NC” refers to NR and CB combination,

“NS” refers to NR and silica combination, and “EC” refers to SR and CB combination, and

“ES” refers to SR and silica combination.

The present invention provides a tyre tread composition comprising at least a diene rubber selected from the group consisting of at least a natural rubber, at least a synthetic rubber, and combinations thereof; at least a reinforcing fdler selected from the group consisting of carbon black, silica, and combinations thereof; and niger seed oil characterized in comprising linoleic acid having concentration of at least 70% of total fatty acids.

The niger seed oil further comprises palmitic acid having concentration of <15% of total fatty acids; stearic acid having concentration of <10% of total fatty acids, and oleic acid having concentration of <20% of total fatty acids. In an embodiment, palmitic acid concentration in niger seed oil is <10% of total fatty acids, more particularly about 9%. In an embodiment, stearic acid concentration in niger seed oil is less than 6% of total fatty acids, more particularly about 5%. In an embodiment, oleic acid concentration in niger seed oil is less than 15% of total fatty acids, more particularly about 14%. In an embodiment, linolenic acid concentration in niger seed oil is about 71% of total fatty acids.

In an embodiment, niger seed oil loading in said composition is in the range of 1-30 phr. In an embodiment, niger seed oil loading in said composition is in the range of 1-25 phr. In another embodiment, niger seed oil loading in said composition is in the range of 1-20 phr. In an embodiment, niger seed oil loading in said composition is in the range of 10-20 phr. In an embodiment, niger seed oil loading in said composition is 25phr. In another embodiment, niger seed oil loading in said composition is 15phr. In still another embodiment, niger seed oil loading in said composition is 5phr. In a preferred embodiment, niger seed oil loading in said composition is lOphr.

In one embodiment, the synthetic rubber (SR) can be selected from the group consisting of polybutadiene rubber (PBD), polyvinyl-butadiene rubber, styrene -butadiene rubber (SBR), solution-polymerized styrene-butadiene rubber (SSBR), emulsion-polymerized styrene -butadiene rubber (ESBR), nitrile rubber (NBR), hydrogenated nitrile rubber, butyl rubber, halogenated butyl rubbers, liquid rubbers, polynorbomene copolymer, isoprene-isobutylene copolymer, chloroprene rubber, ethylene propylene diene monomer rubber (EPDM), acrylate rubber, fluorine rubber, silicone rubber, polysulfide rubber, epichlorohydrin rubber, a terpolymer formed from ethylene monomers, propylene monomers, and/or ethylene propylene diene monomer (EPDM), styrene- isoprene -butadiene terpolymer, hydrated acrylonitrile butadiene rubber, isoprene-butadiene copolymer, hydrogenated styrene-butadiene rubber, butadiene acrylonitrile rubber, styrene- butadiene-styrene block copolymer (SBS), styrene-ethylene/butylene-styrene block copolymer (SEBS), styrene-[ethylene-(ethylene/propylene)]-styrene block copolymer (SEEPS), styreneisoprene -styrene block copolymer (SIS), isoprene-based block copolymers, butadiene-based block copolymers, styrenic block copolymers, hydrogenated styrenic block copolymers, styrene butadiene copolymers, polyisobutylene, ethylene vinyl acetate (EVA) polymers, polyolefins, metallocene-catalyzed polyolefin polymers and elastomers, reactor-made thermoplastic polyolefin elastomers, olefin block copolymer, polyurethane block copolymer, polyamide block copolymer, thermoplastic polyolefins, thermoplastic vulcanizates, ethylene vinyl acetate copolymer, ethylene n-butyl acrylate copolymer, ethylene methyl acrylate copolymer, neoprene, urethane, ethylene acrylic acid copolymer, ethylene-propylene polymers, propylene -hexene polymers, ethylenebutene polymers, ethylene octene polymers, propylene-butene polymers, ethylene -propylene - butylene terpolymers, and a mixture thereof.

In an embodiment, the reinforcing filler in the tyre tread composition is carbon black. In an embodiment, the reinforcing filler in the tyre tread composition is silica. In yet another embodiment, the reinforcing filler is a combination of carbon black and silica.

In an embodiment, carbon black loading in the tyre tread composition is in the range of 30-70 phr. In an embodiment, carbon black in the tyre tread composition is characterized by having N2SA (m²/g) in the range of 75-145 as measured using ATSM D6556. In an embodiment, carbon black in the tyre tread composition is characterized by having OAN (ml/ 100g) in the range of 100-140 as measured using ASTM D2414. In an embodiment, silica loading in the tyre tread composition is in the range of 30-70 phr. In an embodiment, silica in the tyre tread composition is characterized by having N2SA (m²/g) in the range of 100-310.

In an embodiment, where the reinforcing filler in the tyre tread composition comprises silica, the tyre tread composition further comprises at least a silane selected from the group consisting of mercapto silanes, sulfide silanes, and combinations thereof. In an embodiment, the silanes is at least a mercapto silane. In an embodiment, the silanes is at least a sulphide silane. In an embodiment, the silanes is a combination of at least a mercapto silane and at least a sulphide silane.

In another embodiment, the silane loading in the tyre tread composition ranges from 8-20% of silica filler content in phr. In an embodiment, the mercapto silane is selected from the group consisting of Si363, 3-Octanoylthio-l-propyltriethoxysilane (NXT), and combinations thereof. In a preferred embodiment, the mercapto siliane is Si363. In an embodiment, the sulphide silane is selected from the group consisting of Si266, bis(triethoxysilylpropyl) disulfide (TESPD), bis (triethoxysilylpropyl) tetrasulfide (TESPT), and combinations thereof. In a preferred embodiment, the sulphide silane is Si266.

In an embodiment, the tyre tread composition comprises a natural rubber. In an embodiment, the tyre tread composition comprises at least a synthetic rubber. In another embodiment, the tyre tread composition comprises a combination of a natural rubber and at least a synthetic rubber. In an embodiment, natural rubber loading in the tyre tread composition is 100 phr. In an embodiment, the synthetic rubber loading in the tyre tread composition is 100 phr. In an embodiment, synthetic rubber loading in the composition is in the range of 10 to 30 phr, and natural rubber loading in the composition is in the range of 70 to 90 phr. In a preferred embodiment, synthetic rubber loading in the composition is in the range of 10 to 20 phr, and natural rubber loading in the composition is in the range of 80 to 90 phr.

In an embodiment, the tyre tread composition comprises natural rubber, carbon black, niger seed oil, and other chemicals. Carbon black loading in the tyre tread composition is 50 phr, and niger seed oil loading is 5phr. In yet another embodiment, the tyre tread composition comprises natural rubber, silica, silane, niger seed oil, and other chemicals. Silica loading in the tyre tread composition is 55 phr, silane loading is 5.5 phr and niger seed oil loading is 5phr. The silane in the tyre tread composition is sulfide silane Si266.

In an embodiment, the tyre tread composition comprises synthetic rubber, carbon black, niger seed oil, and other chemicals. Carbon black loading in the tyre tread composition is 50 phr, and niger seed oil loading is 5phr. In yet another embodiment, the tyre tread composition comprises synthetic rubber, silica, silane, niger seed oil, and other chemicals. Silica loading in the tyre tread composition is 55 phr, silane loading is 5.5 phr and niger seed oil loading is 5phr. The silane in the tyre tread composition is sulfide silane Si266.

In an embodiment, the tyre tread composition comprises a combination of natural and synthetic rubbers. In another embodiment, the tyre tread composition comprises a combination of carbon black and synthetic rubbers. In yet another embodiment, the tyre tread composition comprises a combination of mercapto silane and sulfide silane. In an embodiment, the tyre tread composition is characterized by having Tan5 value in the range of 0.1-0.3 measured at 70°C. In an embodiment, the tyre tread composition is characterized by having a maximum strength for the Constrained Path Tear of up to 85N measured by test method ASTM D 624.

In an embodiment, the tyre tread composition comprises a combination of natural and synthetic rubbers, carbon black and other chemicals. In the said composition, the loading of natural rubber is in the range of 60 to 80 phr, synthetic rubber is in the range of 20 to 40 phr, and carbon black is in the range of 40 to 60 phr. In an embodiment, the composition further comprises RAE oil in the range of 5 to 30 phr. In another embodiment, the tyre tread composition comprises a combination of natural and synthetic rubbers, carbon black, RAE oil and other chemicals, wherein the RAE oil loading in the composition is 5 phr. In another embodiment, the tyre tread composition comprises a combination of natural and synthetic rubbers, carbon black, RAE oil and other chemicals, wherein the RAE oil loading in the composition is 10 phr. In another embodiment, the tyre tread composition comprises a combination of natural and synthetic rubbers, carbon black, RAE oil and other chemicals, wherein the RAE oil loading in the composition is 15 phr. In another embodiment, the tyre tread composition comprises a combination of natural and synthetic rubbers, carbon black, RAE oil and other chemicals, wherein the RAE oil loading in the composition is 20 phr. In another embodiment, the tyre tread composition comprises a combination of natural and synthetic rubbers, carbon black, RAE oil and other chemicals, wherein the RAE oil loading in the composition is 25 phr.

In an embodiment, the tyre tread composition comprises a combination of natural and synthetic rubbers, carbon black and other chemicals. In the said composition, the loading of natural rubber is in the range of 60 to 80 phr, synthetic rubber is in the range of 20 to 40 phr, and carbon black is in the range of 40 to 60 phr. In an embodiment, the composition further comprises niger oil in the range of 5 to 30 phr. In an embodiment, the tyre tread composition comprises a combination of natural and synthetic rubbers, carbon black, niger oil, and other chemicals, wherein the niger oil loading in the composition is 5 phr. In another embodiment, the tyre tread composition comprises a combination of natural and synthetic rubbers, carbon black, niger oil and other chemicals, wherein the niger oil loading in the composition is 10 phr. In another embodiment, the tyre tread composition comprises a combination of natural and synthetic rubbers, carbon black, niger oil and other chemicals, wherein the niger oil loading in the composition is 15 phr. In another embodiment, the tyre tread composition comprises a combination of natural and synthetic rubbers, carbon black, niger oil and other chemicals, wherein the niger oil loading in the composition is 20 phr. In another embodiment, the tyre tread composition comprises a combination of natural and synthetic rubbers, carbon black, niger oil and other chemicals, wherein the niger oil loading in the composition is 25 phr.

The present invention also provides a tyre comprising a tyre tread composition as substantially described herein. In an embodiment, the tyre is characterized by having improved RRc (Rolling Resistance Coefficient) value.

The advantages of the present invention include improved toughness/durability of the compound comprising niger seed oil over conventional petroleum oil-based compound: higher elongation at break, higher toughness (both aged and unaged), higher constrained path tear strength, lower rolling resistance of the compound comprising the Niger seed oil and lower tan delta at 70°C, and improved mileage of the compound comprising the niger seed oil as evident from lower abrasion loss - LAT 100.

EXAMPLES

The rheological and mechanical properties of the tyre tread composition of the present invention over conventional tyre tread compositions was evaluated based on the following tests and procedures as shown in Table 1 below.

Table 1: Tests and procedures

Experiment 1

A reference tyre tread composition coded as NC-RAE was prepared comprising natural rubber (NR) as the base rubber along with fdlers (carbon black), and process oil (RAE). The rheological properties, physical properties, and the constrained path tear strength of the said tyre tread composition were determined. For evaluation of the rheological, physical properties, constrained path tear strength, and dynamic properties, the sample was cured at 160°C. For evaluation of LAT 100 abrasion resistance, heat build-up properties, and rebound resilience properties, the sample was cured at 150°C. The constrained path tear strength correlates with the cut and chip resistance of the compound. LAT 100 abrasion resistance of the tyre tread composition correlates with the mileage performance of the compound.

Table 2: Tyre tread composition (NC-RAE)

The above composition refers to a compound formulation with NR and RAE oil as the reference. Carbon black N330 is used as the reinforcing fdler. Other chemical includes: Activators (ZnO+Stearic Acid), Antidegradants (TMQ, Wax,6PPD) & Curatives (S & accelerators).

Table 3: Rheological properties of NC-RAE

Scorch time and optimum cure time are determined for compound containing RAE oil as reference.

Table 4: Physical properties of NC-RAE

The physical properties of the rubber compound are determined as per the above Table.

Table 5: Constrained path tear strength of NC-RAE

The above Table discloses the Constrained Path tear strength of the rubber compound. This correlates with the cut and chip resistance of the compound.

Table 6: LAT100 abrasion properties of NC-RAE

The above Table measures the LAT 100 abrasion resistance index of the rubber compound with RAE. This correlates with the mileage performance of the compound.

Table 7: Heat Build Up Properties of NA-RAE

The above Table measures the heat build-up property of the reference compound containing RAE oil. This correlates with the temperature build up in the compound during service condition.

Table 8: Rebound Resilience Properties ofNA-RAE

The above Table measures the rebound resilience of the reference compound containing RAE oil. This correlates with the rolling resistance property of the compound.

Table 9: Dynamic properties (@700C, Static strain: 0.05 % & Dyn.strain:0.02%) ofNA-RAE

The above Table shows the dynamic properties of the reference compound containing RAE oil.

Lower Tan delta value represents lower rolling resistance performance of the compound.

Experiment 2

A reference tyre tread composition coded as NC-TDAE was prepared comprising natural rubber (NR) as the base rubber along with fillers (carbon black), process oil (TDAE), and other chemicals. For evaluation of the rheological, physical properties, constrained path tear strength, and dynamic properties, the sample were cured at 160°C. For evaluation of LAT 100 abrasion resistance, Heat Build Up Properties, and Rebound Resilience Properties, the sample was cured at 150°C.

Table 10: Tyre tread composition (reference) (NC-TDAE)

Table 11: Rheological properties ofNC-TDAE Table 12: Physical properties ofNC-TDAE

Table 13: Constrained path tear strength ofNC-TDAE

Table 14: Abrasion resistance (LAT 100) ofNC-TDAE

Table 15: Heat Build Up Properties ofNC-TDAE

Table 16: Rebound Resilience Properties ofNC-TDAE

Table 17: Dynamic properties (@700C, Static strain: 0.05 % & Dyn.strain:0.02%) ofNC-TDAE

Experiment 3 A reference tyre tread composition coded as NC-NO was prepared comprising natural rubber (NR) as the base rubber along with fillers (carbon black), process oil (Niger oil), and other chemicals. For evaluation of the rheological, physical properties, constrained path tear strength, and dynamic properties, the sample were cured at 160°C. For evaluation of LAT 100 abrasion resistance, heat build-up properties, and rebound resilience properties, the sample was cured at 150°C.

Table 18: Tyre tread composition (NC-NO)

Table 19: Rheological properties of NC-NO

Table 20: Physical properties of NC-NO

Table 21: Constrained path tear strength of NC-NO Table 22: Abrasion resistance (LAT 100) ofNC-NO

Table 23: Heat Build Up Properties of NC-NO

Table 24: Rebound Resilience Properties of NC- NO

Table 25: Dynamic properties (@700C, Static strain: 0.05 % & Dyn.strain:0.02%) ofNC-NO

Table 26: Comparison of formulations of NC-RAE, NC-TDAE and NC-NO

The above table shows a comparison of the formulation of the different tyre tread compositions comprising natural rubber. Each of the formulations vary in the type of process oil constituting the composition.

Table 27: Comparison of Rheological properties ofNC-RAE, NC-TDAE and NC-NO

The above table shows that scorch time (TS2) and optimum cure time (TC90) of NC-NO containing tyre tread composition is comparable with NC-RAE and NC-TDAE.

Table 28: Comparison of Physical properties ofNC-RAE, NC-TDAE and NC-NO As per the above table, the tyre tread composition comprising NC-NO shows an improvement in Elongation at break% compared to reference compounds (NC-RAE, NC-TDAE).

Table 29: Comparison of Constrained path tear strength ofNC-RAE, NC-TDAE and NC-NO

Table 29 shows that the tyre tread composition comprising NC-NO shows an improvement in tear strength compared to NC-RAE and NC-TDAE

Table 30: Comparison of Abrasion resistance (LAT 100) of NC-RAE, NC-TDAE and NC-NO

Table 30 shows that the tyre composition comprising NC-NO shows comparable abrasion resistance properties with respect to tyre tread compositions comprising each of NC-RAE and NC- TDAE.

Table 31: Comparison of Heat Build Up Properties of NC-RAE, NC-TDAE, and NC-NO

The tyre tread composition comprising NC-NO shows comparable heat build -up properties with respect to tyre tread compositions each comprising NC-RAE and NC-TDAE.

Table 32: Comparison of Rebound Resilience Properties of NC-RAE, NC-TDAE, and NC-NO

The rebound resilience properties of NC-NO containing tyre tread composition is superior to those containing NC-RAE and NC-TDAE.

Table 33: Comparison of Dynamic properties (@700C, Static strain: 0.05 % & Dyn.strain:0.02%) of of NC-RAE, NC-TDAE, and NC-NO

NC-NO containing tyre tread compositions shows lower Tan delta than NC-RAE or NC-TDAE containing tyre tread compositions.

Experiment 4

A reference tyre tread composition coded as EC-RAE was prepared comprising synthetic rubber (ESBR) as the base rubber along with fdlers (carbon black), process oil (RAE), and other chemicals. The rheological properties, physical properties, and the constrained path tear strength of the said tyre tread composition were determined. For evaluation of the rheological, physical properties, constrained path tear strength, and dynamic properties, the sample were cured at 160°C. For evaluation of LAT 100 abrasion resistance, heat build-up properties, and rebound resilience properties, the sample was cured at 150°C. The constrained path tear strength correlates with the cut and chip resistance of the compound. LAT 100 abrasion resistance of the tyre tread composition correlates with the mileage performance of the compound.

Table 34: Tyre tread composition (EC-RAE)

Table 35: Rheological properties of EC-RAE

Table 36: Physical properties of EC-RAE

Table 37: Aged Toughness of EC-RAE

Table 38: Constrained path tear strength of EC-RAE

Table 39: LAT100 abrasion properties of EC-RAE

Table 40: Heat Build Up Properties of EC-RAE

Table 41: Rebound Resilience Properties of EC-RAE Table 42: Dynamic properties (@700C, Static strain: 0.05 % & Dyn.strain:0.02%) of EC-RAE

Experiment 5

A reference tyre tread composition coded as EC-TDAE was prepared comprising synthetic rubber (ESBR) as the base rubber along with fdlers (carbon black), process oil (TDAE), and other chemicals. For evaluation of the rheological, physical properties, constrained path tear strength, and Dynamic properties, the sample were cured at 160°C. For evaluation of LAT 100 abrasion resistance, Heat Build Up Properties, and Rebound Resilience Properties, the sample was cured at 150°C.

Table 43: Tyre tread composition (EC-TDAE)

Table 44: Rheological properties of EC-TDAE

Table 45: Physical properties of EC-TDAE

Table 46: Aged Toughness of EC-TDAE Table 47: Constrained path tear strength of EC-TDAE

Table 48: Abrasion resistance (LAT 100) of EC-TDAE

Table 49: Heat Build Up Properties of EC-TDAE

Table 50: Rebound Resilience Properties of EC-TDAE

Table 51: Dynamic properties (@700C, Static strain: 0.05 % & Dyn.strain:0.02%) of EC-TDAE Experiment 6 A reference tyre tread composition coded as EC-NO was prepared comprising synthetic rubber (ESBR) as the base rubber along with fdlers (carbon black), process oil (Niger oil), and other chemicals. For evaluation of the rheological, physical properties, constrained path tear strength, and dynamic properties, the sample were cured at 160°C. For evaluation of LAT 100 abrasion resistance, heat build up properties, and rebound Resilience Properties, the sample was cured at 150°C.

Table 52: Tyre tread composition (EC-NO)

Table 53: Rheological properties of EC-NO

Table 54: Physical properties of EC-NO

Table 55: Aged Toughness of EC-NO

Table 56: Constrained path tear strength of EC-NO Table 57: Abrasion resistance (LAT 100) of EC-NO

Table 58: Heat Build Up Properties of EC-NO

Table 59: Rebound Resilience Properties of EC- NO

Table 60: Dynamic properties (@700C, Static strain: 0.05 % & Dyn.strain:0.02%) of EC-NO

Table 61: Comparison of formulations of EC-RAE, EC-TDAE and EC-NO The above table shows a comparison of the formulation of the different tyre tread compositions comprising synthetic rubber. Each of the formulations vary in the type of process oil constituting the composition. Table 62: Comparison of Rheological properties of EC-RAE, EC-TDAE and EC-NO

The above table shows that scorch time (TS2) and optimum cure time (TC90) of NO containing tyre tread composition is comparable with those containing RAE and TDAE.

Table 63: Comparison of Physical properties of EC-RAE, EC-TDAE and EC-NO

Table 63 shows that rubber compound with NO as process oil shows an improvement in tensile strength and elongation break% as compared to the reference compounds.

Table 64: Comparison of Aged Toughness of EC-RAE, EC-TDAE and EC-NO Table 64 shows that rubber compound with NO shows a significant improvement in aged toughness. Table 65: Comparison of Constrained path tear strength of EC-RAE, EC-TDAE and EC-NO The above table shows that the constrained path tear strength for all the three types of formulation is comparable.

Table 66: Comparison of Abrasion resistance (LAT 100) of EC-RAE, EC-TDAE and EC-NO

Table 66 shows that the tyre composition comprising EC-NO shows comparable abrasion resistance properties with respect to tyre tread compositions comprising each of EC-RAE and EC- TDAE. Table 67: Comparison of heat buildup properties of EC-RAE, EC-TDAE, and EC-NO

The tyre tread composition EC-NO shows comparable heat build -up properties with EC-RAE and EC-TDAE.

Table 68: Comparison of Rebound Resilience Properties of EC-RAE, EC-TDAE, and EC-NO

The rebound resilience properties of the rubber formulation EC-NO is comparable to that of the reference formulations, EC-RAE and EC-TDAE.

Table 69: Comparison of Dynamic properties (@700C, Static strain: 0.05 % & Dyn.strain:0.02%) of EC-RAE, EC-TDAE, and EC-NO

Rubber compound with NO shows a comparable E’ and Tan delta with respect to tyre tread compositions comprising each of RAE and TDAE oil.

Experiment 7

A reference tyre tread composition coded as NS-RAE was prepared comprising natural rubber (NR) as the base rubber along with fdlers (silica), silane, process oil (RAE), and other chemicals. The rheological properties, physical properties, and the constrained path tear strength of the said tyre tread composition were determined. For evaluation of the rheological, physical properties, constrained path tear strength, and Dynamic properties, the sample were cured at 160°C. For evaluation of LAT 100 abrasion resistance, Heat Build Up Properties, and Rebound Resilience Properties, the sample was cured at 150°C. The constrained path tear strength correlates with the cut and chip resistance of the compound. LAT 100 abrasion resistance of the tyre tread composition correlates with the mileage performance of the compound.

Table 70: Tyre tread composition (NS-RAE)

Table 71: Rheological properties of NS-RAE

Table 72: Physical properties of NS-RAE Table 73: Aged Toughness of NS-RAE

Table 74: Constrained path tear strength of NS-RAE

Table 75: LAT100 abrasion properties of NS-RAE

Table 76: Heat Build Up Properties of NS-RAE

Table 77: Rebound Resilience Properties of NS-RAE Table 78: Dynamic properties (@700C, Static strain: 0.05 % & Dyn.strain:0.02%) ofNS-RAE Experiment 8

A reference tyre tread composition coded as NS-TDAE was prepared comprising natural rubber (NR) as the base rubber along with fdlers (silica), silane, process oil (TDAE), and other chemicals. For evaluation of the rheological, physical properties, constrained path tear strength, and dynamic properties, the sample were cured at 160°C. For evaluation of LAT 100 abrasion resistance, heat build up properties, and rebound resilience properties, the sample was cured at 150°C.

Table 79: Tyre tread composition (NS-TDAE) Table 80: Rheological properties of NS-TDAE

Table 81: Physical properties of NS-TDAE

Table 82: Aged Toughness of NS-TDAE Table 83: Constrained path tear strength of NS-TDAE

Table 84: Abrasion resistance (LAT 100) of NS-TDAE

Table 85: Heat Build Up Properties of NS-TDAE

Table 86: Rebound Resilience Properties of NS-TDAE

Table 87: Dynamic properties (@700C, Static strain: 0.05 % & Dyn.strain:0.02%) ofNS-TDAE Experiment 9

A reference tyre tread composition coded as NS-NO was prepared comprising natural rubber (NR) as the base rubber along with fdlers (silica), silane (Si266), process oil (Niger oil), and other chemicals. For evaluation of the rheological, physical properties, constrained path tear strength, and Dynamic properties, the sample were cured at 160°C. For evaluation of LAT 100 abrasion resistance, Heat Build Up Properties, and Rebound Resilience Properties, the sample was cured at 150°C.

Table 88: Tyre tread composition (NS-NO)

Table 89: Rheological properties of NS-NO

Table 90: Physical properties of NS-NO Table 91: Aged Toughness ofNS-NO

Table 92: Constrained path tear strength of NS-NO

Table 93: Abrasion resistance (LAT 100) ofNS-NO Table 94: Heat Build Up Properties ofNS-NO

Table 95: Rebound Resilience Properties ofNS-NO

Table 96: Dynamic properties (@700C, Static strain: 0.05 % & Dyn.strain:0.02%) ofNS-NO

Table 97: Comparison of formulations of NS-RAE, NS-TDAE and NS-NO

Table 98: Comparison of Rheological properties ofNS-RAE, NS-TDAE and NS-NO

The above table shows that scorch time (TS2) and optimum cure time (TC90) of EC-NO containing tyre tread composition is comparable with those containing EC-RAE and EC-TDAE.

Table 99: Comparison of Physical properties ofNS-RAE, NS-TDAE and NS-NO Table 99 shows that rubber compound with NO as process oil shows an improvement in elongation break% as compared to the reference compounds.

Table 100: Comparison of Aged Toughness ofNS-RAE, NS-TDAE and NS-NO Table 100 shows that rubber compound with NO shows a significant improvement in aged toughness.

Table 101: Comparison of Constrained path tear strength of NS-RAE, NS-TDAE, and NS-NO

The above table infers that the NO containing tyre tread composition shows an improvement in constrained path tear strength as compared to all the other two types of formulation. Table 102: Comparison of Abrasion resistance (LAT 100) of EC-RAE, EC-TDAE and EC-NO

The tyre tread composition comprising NO shows improved abrasion resistance properties as compared to tyre tread compositions EC-RAE or EC-TDAE.

Table 103: Comparison of Heat Build Up Properties of NS-RAE, NS-TDAE, and NS-NO

Table 104: Comparison of Rebound Resilience Properties of NS-RAE, NS-TDAE, and NS-NO

The rebound resilience properties of the rubber formulation EC-NO is comparable to that of the reference formulations, EC-RAE and EC-TDAE. Table 105: Comparison of Dynamic properties (@700C, Static strain: 0.05 % &

Dyn.strain:0.02%) ofNS-RAE, NS-TDAE, and NS-NO

Experiment 10

A reference tyre tread composition coded as ES-RAE was prepared comprising synthetic rubber (ESBR) as the base rubber along with fillers (silica), silane, process oil (RAE), and other chemicals. The rheological properties, physical properties, and the constrained path tear strength of the said tyre tread composition were determined. For evaluation of the rheological, physical properties, constrained path tear strength, and Dynamic properties, the sample were cured at 160°C. For evaluation of LAT 100 abrasion resistance, Heat Build Up Properties, and Rebound Resilience Properties, the sample was cured at 150°C. The constrained path tear strength correlates with the cut and chip resistance of the compound. LAT 100 abrasion resistance of the tyre tread composition correlates with the mileage performance of the compound.

Table 106: Tyre tread composition (ES-RAE)

Table 107: Rheological properties of ES-RAE

Table 108: Physical properties of ES-RAE Table 109: Aged Toughness of ES-RAE

Table 110: Constrained path tear strength of ES-RAE

Table 111: LAT100 abrasion properties of ES-RAE

Table 112: Heat Build Up Properties of ES-RAE

Table 113: Rebound Resilience Properties of ES-RAE

Table 114: Dynamic properties (@700C, Static strain: 0.05 % & Dyn.strain:0.02%) of NS-RAE

Experiment 11

A reference tyre tread composition coded as ES-TDAE was prepared comprising synthetic rubber (ESBR) as the base rubber along with fillers (silica), silane, process oil (TDAE), and other chemicals. For evaluation of the rheological, physical properties, constrained path tear strength, and Dynamic properties, the sample were cured at 160°C. For evaluation of LAT 100 abrasion resistance, Heat Build Up Properties, and Rebound Resilience Properties, the sample was cured at 150°C.

Table 115: Tyre tread composition (ES-TDAE)

Table 116: Rheological properties of ES-TDAE

Table 117: Physical properties of ES-TDAE

Table 118: Aged Toughness of ES-TDAE

Table 119: Constrained path tear strength of ES-TDAE

Table 120: Abrasion resistance (LAT 100) of ES-TDAE

Table 121: Heat Build Up Properties of ES-TDAE Table 122: Rebound Resilience Properties of ES-TDAE

Table 123: Dynamic properties (@700C, Static strain: 0.05 % & Dyn.strain:0.02%) of ES-TDAE

Experiment 12

A reference tyre tread composition coded as ES-NO was prepared comprising synthetic rubber (ESBR) as the base rubber along with fdlers (silica), silane (Si266), process oil (Niger oil), and other chemicals. For evaluation of the rheological, physical properties, constrained path tear strength, and dynamic properties, the sample were cured at 160°C. For evaluation of LAT 100 abrasion resistance, heat buildup properties, and rebound resilience properties, the sample was cured at 150° C. Table 124: Tyre tread composition (ES-NO)

Table 125: Rheological properties of ES-NO

Table 126: Physical properties of ES-NO

Table 127: Aged Toughness of ES-NO Table 128: Constrained path tear strength of ES-NO

Table 129: Abrasion resistance (LAT 100) of ES-NO

Table 130: Heat Build Up Properties of ES-NO

Table 131: Rebound Resilience Properties of ES-NO

Table 132: Dynamic properties (@700C, Static strain: 0.05 % & Dyn.strain:0.02%) of ES-NO Table 133: Comparison of formulations of ES-RAE, ES-TDAE and ES-NO

The above table shows a comparison of the formulation of the different tyre tread compositions comprising synthetic rubber. Each of the formulations vary in the type of process oil constituting the composition.

Table 134: Comparison of Rheological properties of ES-RAE, ES-TDAE and ES-NO

Table 135: Comparison of Physical properties of ES-RAE, ES-TDAE and ES-NO Table 135 shows that rubber compound with NO as process oil shows an improvement in elongation break% as compared to the reference compounds. Table 136: Comparison of Aged Toughness of ES-RAE, ES-TDAE and ES-NO

Table 136 shows that rubber compound with NO shows a significant improvement in aged toughness.

Table 137: Comparison of Constrained path tear strength of ES-RAE, ES-TDAE, and ES-NO

The above table shows that the constrained path tear strength for all the three types of formulation is comparable.

Table 138: Comparison of Abrasion resistance (LAT 100) of ES-RAE, ES-TDAE and ES-NO

Table 138 shows that the tyre composition comprising ES-NO shows comparable abrasion resistance properties with respect to tyre tread compositions comprising each of ES-RAE and ES- TDAE.

Table 139: Comparison of Heat Build Up Properties of ES-RAE, ES-TDAE and ES-NO

The tyre tread composition EC-NO shows comparable heat build -up properties with ES-RAE and ES-TDAE.

Table 140: Comparison of Rebound Resilience Properties of ES-RAE, ES-TDAE and ES-NO

The rebound resilience properties of the rubber formulation ES-NO is comparable to that of the reference formulations, ES-RAE and ES-TDAE.

Table 141: Comparison of Dynamic properties (@700C, Static strain: 0.05 % & Dyn.strain:0.02%) of ES-RAE, ES-TDAE and ES-NO

Experiment 13

The effect of varying loading amount of niger seed oil (process oil) was also studied using niger seed oil loading in the amounts of 1, 5, 10, 15, and 25 phr. Reference tyre tread composition was prepared using natural rubber as the base rubber along with carbon black (N330) as filler.

Table 142

Table 143: Characterization

As seen from Table 143 above, regarding rheological properties, it can be seen that with increasing oil dosage, there is not a significant change in scorch safety (TS2) or optimum cure time (Tc90). Regarding physical properties, increasing oil dosage leads to decrease in Shore-A hardness (tread). It is to be noted that in the tyre industry, Shore-A hardness of upto 60 is generally acceptable for a standard tread compound. Regarding reinforcibility index (M300/M100), there is not much change with increasing oil dosage. Regarding tensile strength and tear strength (Angle tear), there is an oil dosage dependent decrease, while regarding EB%, there is an oil dosage dependent increase. With respect to dynamic properties as measured in DMA+1000, there is an oil dosage dependent decrease in E’, while regarding Tan delta, optimum value is achieved at oil dosage of lOphr. Similarly, regarding abrasion resistance, optimum value is achieved at oil dosage of lOphr and increased oil dosage leads to reduction in abrasion resistance.

These results in conjunction with the previous studies provided in this specification demonstrate that niger seed oil is a suitable replacement (and across certain measured parameters, superior replacement) for aromatic oils, and low-PAHs petroleum-based oils as process oil for use in tyre compounding without affecting the mechanical properties of the tyre. Thus, niger seed oil is demonstrably a suitable environment-friendly and environmentally sustainable replacement to conventional process oils.

Claims

I/We claim:

1. A tyre tread composition comprising: a. at least a diene rubber selected from the group consisting of at least a natural rubber, at least a synthetic rubber, and combinations thereof; b . at least a reinforcing filler selected from the group consisting of carbon black, silica, and combinations thereof; and c. niger seed oil characterized in that the niger seed oil comprises linoleic acid having concentration of at least 70% of total fatty acids.

2. The composition as claimed in claim 1, wherein niger seed oil further comprises palmitic acid having concentration of <15% of total fatty acids; stearic acid having concentration of <10% of total fatty acids, and oleic acid having concentration of <20% of total fatty acids.

3. The composition as claimed in claim 1, wherein niger seed oil loading in said composition is in the range of 1-30 phr.

4. The composition as claimed in claim 1, wherein carbon black is characterized by having N2SA (m²/g) in the range of 75-145 and OAN (ml/ 100g) in the range of 100-140.

5. The composition as claimed in claim 1, wherein silica is characterized by having N2SA (m²/g) in the range of 100-310.

6. The composition as claimed in claim 1, wherein carbon black, silica, or combination of carbon black and silica loading in said composition is in the range of 30-70 phr.

7. The composition as claimed in claim 1 , wherein said composition comprises silica as fdler or in combination with carbon black; and said composition further comprises at least a silane.

8. The composition as claimed in claim 6, wherein silane loading in said composition is in the range of 8-20% of silica fdler content in phr.

9. The tyre tread composition as claimed in claim 6, wherein at least a silane is selected from the group consisting of Si363, 3-Octanoylthio-l -propyltriethoxysilane (NXT), bis(triethoxysilylpropyl) disulfide (TESPD), bis (triethoxysilylpropyl) tetrasulfide (TESPT), and combinations thereof.

10. The tyre tread composition as claimed in claim 1, wherein at least a diene rubber is one of natural rubber having loading of 100 phr; synthetic rubber having loading of 100 phr; or a combination of natural rubber and synthetic rubber, wherein the synthetic rubber loading is in the range of 10 to 30 phr, and natural rubber loading is in the range of 70 to 90 phr.

11. The tyre tread composition as claimed in claim 10, wherein in the combination of natural rubber and synthetic rubber, synthetic rubber loading is in the range of 10 to 20 phr, and natural rubber loading is in the range of 80 to 90 phr.

12. The tyre tread composition as claimed in claim 1, characterized by at least one of having Tan5 value measured at 70°C in the range of 0. 1-0.3, and having a maximum strength for the Constrained Path Tear of up to 85N measured by test method ASTM D 624.

13. A tyre comprising a tyre tread composition as claimed in any of the preceding claims.