DESC:TECHNICAL FIELD
The present disclosure generally relates to the field of tyre technology, and pertains to compositions employed for manufacturing of tyres. More particularly, the present disclosure provides a tyre composition comprising ionic liquid functionalized graphene as a reinforcing filler. The inclusion of said ionic liquid functionalized graphene in the tyre composition in addition to lending enhanced properties and life to the tyre, reduces the curing/vulcanization time during preparing of tyre compositions/products, when compared to the significant time which is needed when typical graphene is incorporated in rubber compositions. A tyre made of the present composition is also superior to a tyre manufactured using a composition comprising traditional fillers, such as carbon black, or typical graphene. The disclosure also provides a corresponding process that allows incorporation of the said ionic liquid functionalized graphene along with one or more types of rubbers for preparing the said composition.

BACKGROUND OF THE DISCLOSURE
With an ever-increasing number of cars worldwide, automotive and tyre industries play a vital role in reducing carbon dioxide footprint by reducing car fuel consumption and increasing tyre mileage without compromising on driving safety and ride quality. For this reason, tyre industries have been in a continuous development activity to expand the so-called magic triangle comprising of rolling resistance, abrasion resistance, and wet grip. A detailed look at the magic triangle reveals that lowering the rolling resistance of tyres reduces the fuel consumption of a car, whereas the higher abrasion resistance of tyres ensures higher mileage and higher lifetime, while high wet grip ensures safety.

A tyre's composition affects grip, fuel economy and its lifetime. To adapt the property profiles of elastomer materials for car tyres with respect to the requirements of energy efficiency, adhesion and expanded life time, an incorporation and finest possible dispersion of nanoscale filler particles in the polymer matrix is necessary.

In a typical tyre formulation used widely in industries, 45 to 55 parts of high abrasion furnace carbon black such as N330 is employed as a reinforcing filler to improve mechanical properties of the elastomer. However, use of carbon black is associated with several drawbacks, such as poor heat dissipation and high rolling resistance. Further, the magic triangle properties cannot be improved beyond certain limit with carbon black alone. Typical use of carbon black requires higher loadings to achieve desired properties, which leads to increase in weight, and more material consumption and as a result higher carbon footprint as carbon black has fossil fuel as its source.

Graphene is a two-dimensional wonder material that holds great potential to enter new markets and replace existing materials. With the advent of new graphene-based products every day, it is certain that graphene is a disruptive technology waiting to be commercialized. One such application is in car tyres. Graphene with its high surface area, nano size effects and unique physical properties has emerged as a new potential material for replacing carbon black for reinforcement of elastomers. Thus, while graphene can be employed for weight reduction of the tyre thereby allowing for better fuel efficiency and tensile modulus, keeping in mind the properties of graphene, it also impacts rolling resistance, abrasion loss, fatigue failures, and heat build-up of tyres.

However, graphene incorporation as filler into elastomer tyre formulations increases the curing time significantly. Thus, there is a need to find alternatives that allow addition or incorporation of graphene in tyre compositions without causing increase in curing/vulcanization time of the resulting rubber.

SUMMARY OF THE DISCLOSURE
The present disclosure relates to a tyre composition comprising ionic liquid functionalized graphene as a reinforcing filler. More particularly, the present disclosure relates to a tyre composition comprising a rubber and ionic liquid functionalized graphene.

In embodiments of the present disclosure, the composition comprises at least one rubber including but not limited to styrene-butadiene rubber (SBR), polybutadiene rubber (PBR), butyl rubber, halo butyl rubber, ethylene propylene diene methylene rubber (EPDM), silicone rubber and natural rubber, and ionic liquid functionalized graphene.

In embodiments of the present disclosure, the rubber is at a concentration ranging from about 10% (w/w) to 95% (w/w) and the ionic liquid functionalized graphene at a concentration ranging from about 0.01% to about 18%.

In embodiments of the present disclosure, the tyre composition herein is prepared by either completely or partially replacing a traditional reinforcing filler by ionic liquid functionalized graphene, or by adding the graphene and ionic liquid in addition to the traditional reinforcing filler.

In embodiments of the present disclosure, the tyre composition herein provides for better fuel efficiency and tensile modulus, and results in reduction of rolling resistance, abrasion loss, fatigue failures, and heat build-up.

In embodiments of the present disclosure, the functionalization of graphene reduces the curing/vulcanization time of the tyre composition, which is otherwise high when non-functionalized graphene or conventional fillers such as carbon black is used.

In embodiments of the present disclosure, the present composition further comprises an additive selected from a group comprising filler, plasticizer, chemicals, metal reinforcements, textile reinforcements, processing oil, accelerator, anti-oxidant and combinations thereof.

In embodiments of the present disclosure, the additive is at a concentration ranging from about 10% (w/w) to about 60% (w/w).

The present disclosure also relates to a process for preparing the tyre composition of the present disclosure.

In embodiments of the present disclosure, the process comprises mixing graphene, rubber/elastomer, ionic liquid and additive to prepare the composition.

In preferred embodiments of the present disclosure, the mixing step in the preparation process of the tyre composition comprises high shear mixing.

In more preferred embodiments of the present disclosure, the process comprises:
a) high shear mixing of graphene with a solvent to form a graphene mixture; and
b) adding rubber/elastomer, ionic liquid and additive to the graphene mixture, and mixing in an internal mixer to prepare the composition.
In other preferred embodiments of the present disclosure, the process comprises:
a) mixing graphene and rubber by melt-mixing to form a mixture; and
b) adding ionic liquid and additive to the mixture, and mixing to prepare the composition.

The present disclosure also relates to the application of the tyre composition for manufacturing of tyres having enhanced properties, performance and life. In embodiments of the present disclosure, the present disclosure provides tyre product comprising the composition described herein.

DETAILED DESCRIPTION OF THE DISCLOSURE
In view of the drawbacks associated, and to remedy the need created by the art available in the field of tyre technology, the present disclosure aims to provide a composition comprising one or more types of rubbers along with graphene as a filler, wherein the graphene is a functionalized graphene. In particular, the present disclosure relates to a composition comprising a rubber and ionic liquid functionalized graphene. More particularly, the present disclosure provides a tyre composition having at least one rubber selected from a group comprising styrene-butadiene rubber (SBR), polybutadiene rubber (PBR), butyl rubber, halo butyl rubber, ethylene propylene diene methylene rubber (EPDM), silicone rubber and natural rubber, along with ionic liquid functionalized graphene as a reinforcing filler, and further additives. The disclosure also provides a corresponding process that allows functionalization of the said graphene and its inclusion along with one or more of the said rubbers and additives for preparing the composition of the present disclosure.

However, before describing the invention in greater detail, it is important to take note of the common terms and phrases that are employed throughout the instant disclosure for better understanding of the technology provided herein.

Throughout the present disclosure, the term ‘graphene’ is intended to convey the ordinary conventional meaning of the term known to a person skilled in the art and intends to cover ‘graphene’ as an allotrope of carbon consisting of a single or multiple layers of carbon atoms. Thus, the graphene employed in the present disclosure maybe a single layered or multi layered graphene. The graphene employed herein is preferably of high surface area, typically ranging between 1500 to 3000 m2/g.

Throughout the present disclosure, the term ‘ionic liquid’ is intended to convey the ordinary conventional meaning of the term known to a person skilled in the art and intends to cover a salt in the liquid state below 100°C or at room/ambient temperature or those who have melting points below room temperature or including below 0°C. Ionic liquids typically have negligible vapor pressure, high thermal stability, and are non-flammable.

Throughout the present disclosure, the term ‘functionalized’ or ‘functionalization’ is used interchangeably and is intended to convey the ordinary conventional meaning of the term known to a person skilled in the art in the field of polymer or material science, and intends to cover a process of adding new functions, features, capabilities, or properties to a material by changing the surface chemistry of the material. In the context of graphene employed in the present disclosure, the term is used to cover functionalization of graphene including reactions of graphene (and its derivatives) with organic and/or inorganic molecules, chemical modification of the graphene surface, and the interaction of various covalent and noncovalent components with graphene. The functionalization of graphene is surface modification used to reduce the cohesive force between the graphene sheets and to manipulate the physical and chemical properties of graphene. This functionalization of graphene is also referred to as ‘ionic liquid functionalized graphene’ in the present disclosure.

Throughout the present disclosure, the term ‘tyre’ is intended to convey the ordinary conventional meaning of the term known to a person skilled in the art and intends to cover tyre of any composition, comprising at least one rubber/elastomer. Accordingly, in the present disclosure, any reference to a ‘composition’ is intended to refer to any composition known to a person skilled in the art which is used in manufacturing of a tyre.

Throughout the present disclosure, technical terms such as ‘fuel efficiency’, ‘tensile modulus’, ‘rolling resistance’, ‘abrasion resistance’, ‘abrasion loss’, ‘fatigue failure’, and ‘heat build-up’ are used to describe the properties of a tyre or characteristics of a composition that makes up the tyre, and are intended to convey the ordinary conventional meaning of the terms known to a person skilled in the art.

Throughout the present disclosure, the compositions described herein may comprise additional components such as additives such that the total wt% of the composition is 100.
Accordingly, to reiterate, the present disclosure relates to a composition having at least one rubber including but not limited to styrene-butadiene rubber (SBR), polybutadiene rubber (PBR), butyl rubber, halo butyl rubber, ethylene propylene diene methylene rubber (EPDM), silicone rubber and natural rubber, along with ionic liquid functionalized graphene as a reinforcing filler. Further, any rubber/elastomer which is known for production of tyre can be employed according to the present disclosure. The present composition is typically used for manufacturing a tyre and improves its properties such as rolling resistance, abrasion resistance and wet grip, along with other physical properties.

While the conventionally known tyre compositions employ different compounds as reinforcing filler, with carbon black and silica being the most common; the present disclosure also provides a tyre composition where either the traditional reinforcing filler is completely or partially replaced by the functionalized graphene, or where the functionalized graphene is added in addition to the traditional reinforcing filler. Thus, the composition provided by the present disclosure includes but is not limited to a previously known tyre composition or a new tyre composition, where ionic liquid functionalized graphene is employed as the sole or additional reinforcing filler. The graphene so employed is of high surface area, typically ranging between 100 to 3000 m2/g, and preferably of about 300-2000 m2/g.

As mentioned previously, incorporation of graphene in tyre compositions increase curing or vulcanization time of the rubber so produced. To remedy the same, in the present disclosure, graphene employed as a reinforcing filler is functionalized with ionic liquid and has been used to tune the curing time of compositions containing a combination of rubbers/elastomers, used to make tyres. The ionic liquid functionalized graphene considerably accelerates the curing process by at least 50% without affecting the mechanical properties of graphene or the composition as a whole.

In embodiments of the present composition, the rubber is at a concentration ranging from about 10% (w/w) to 95% (w/w) and the ionic liquid functionalized graphene is at a concentration ranging from about 0.01% (w/w) to about 18% (w/w).

In embodiments of the present composition, graphene reacts with ionic liquid to form the ionic liquid functionalized graphene in the composition.

In embodiments of the present composition, the ionic liquid comprises anions selected from a group comprising bromide, chloride, tetrafluoroborate, hexafluorophosphate, triflurosulfonamides, triflurosulfates, dicyanmides, tosylates, triflates other common anions, and combinations thereof.

In embodiments of the present composition, the ionic liquid comprises cations selected from a group comprising long chain aliphatic cationic group, Imidazolium derivatives, guanidiniums, ammonium, pyridinium, phosphonium, tributylmethyl phosphonium, sulfonium, pyrrolidinium and combinations thereof.

In some embodiments of the present composition, the long chain aliphatic cationic group comprises alkyl chains selected from a group comprising allyl-, ethyl-, butyl-, hexyl-, octyl-, decyl-, dodecyl-, hexadecyl-, octadecyl- chains, and combinations thereof.

In preferred embodiments of the present composition, the ionic liquid is selected from a group comprising trihexyltetradecylphosphonium bromide, alkyl imidazolium salt, alkyl pyridinium salt, alkyl pyrrolidinium salt, ammonium salt, pyridinium chloride, pyridinium bromide, tetrahexyl ammonium bromide, trihexyldecyl ammonium bromide, tetrahexyldecyl phosphonium bromide, and combinations thereof.

In embodiments of the present composition, the rubber/elastomer is selected from a group comprising styrene-butadiene rubber (SBR), polybutadiene rubber (PBR), butyl rubber (BR), halo butyl rubber, ethylene propylene diene methylene rubber (EPDM), silicone rubber, natural rubber (NR) and combinations thereof.

In embodiments of the present disclosure, the tyre composition comprises styrene-butadiene rubber (SBR), polybutadiene rubber (PBR) and ionic liquid functionalized graphene.

In embodiments of the present disclosure, the tyre composition comprises polybutadiene rubber (PBR) and ionic liquid functionalized graphene.

In embodiments of the present disclosure, the tyre composition further comprises an additive.

In embodiments of the present disclosure, the tyre composition comprises an additive selected from a group comprising filler, plasticizer, chemicals, metal reinforcements, textile reinforcements, zinc oxide, stearic acid, sulphur, processing oil, accelerator, anti-oxidant, and combinations thereof.

In embodiments of the present disclosure, the tyre composition further comprises additive at a concentration ranging from about 10% (w/w) to about 60% (w/w).

In embodiments of the present disclosure, the additive is a filler selected from a group comprising carbon black, silica, clay, graphene and combinations thereof.

In embodiments of the present disclosure, the plasticizer is selected from a group comprising pre-crosslinked acrylonitrile co-polymer (CCF resin), wood resin, Coumarone-Indene resin (CI) and combinations thereof.

In embodiments of the present disclosure, the chemicals are selected from a group comprising vulcanization aids, vulcanizing agents, and a combination thereof.

In embodiments of the present disclosure, the metal reinforcements are selected from a group comprising steel, high carbon steel high-strength strands, and combinations thereof.

In embodiments of the present disclosure, the textile reinforcements are selected from a group comprising polyamide, polyester, and combinations thereof.

In embodiments of the present disclosure, the processing oil is selected from a group comprising aromatic oil, naphthenic oil, paraffinic oil, and combinations thereof.

In embodiments of the present disclosure, the accelerator is selected from a group comprising N- tert-butyl-benzothiazole sulfonamide (TBBS), N-(1,3-Dimethylbutyl)-N’-phenyl-p-phenylenediamine (TBzTD), N-Cyclohexyl-2-benzothiazole sulfonamide (CBS), and combinations thereof.

In embodiments of the present disclosure, the antioxidant is selected from a group comprising 2,2,4-Trimethyl-1,1-dihydroquinoline (TMQ), N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), phenolics, and combinations thereof.

In embodiments of the present disclosure, the vulcanization aid is selected from a group comprising zinc oxide, stearic acid and a combination thereof.

In embodiments of the present disclosure, the vulcanizing agent is sulphur.

In embodiments of the present disclosure, the composition comprises about 64% (w/w) of styrene-butadiene rubber (SBR), about 27% (w/w) of polybutadiene rubber (PBR), about 2.6% (w/w) of ionic liquid functionalized graphene, about 2.8% (w/w) of zinc oxide, about 1% (w/w) of stearic acid, about 1% (w/w) of N- tert-butyl-benzothiazole sulfonamide (TBBS), and about 1.6% (w/w) of sulphur.

In an exemplary embodiment of the present disclosure, the tyre composition comprises 63.93% (w/w) of styrene-butadiene rubber (SBR), 27.40% (w/w) of polybutadiene rubber (PBR), 2.51% (w/w) of ionic liquid functionalized graphene, 2.74% (w/w) of zinc oxide, 0.91% (w/w) of stearic acid, 0.91% (w/w) of N- tert-butyl-benzothiazole sulfonamide (TBBS), and 1.60% (w/w) of sulphur.

In embodiments of the present disclosure, the composition comprises about 90.6% (w/w) of polybutadiene rubber (PBR), about 2.8% (w/w) of ionic liquid functionalized graphene, about 2.7% (w/w) of zinc oxide, about 1.8% (w/w) of stearic acid, about 0.8% (w/w) of N- tert-butyl-benzothiazole sulfonamide (TBBS), and about 1.3% (w/w) of Sulphur.

In an exemplary embodiment of the present disclosure, the tyre composition comprises 90.79% (w/w) of polybutadiene rubber (PBR), 2.50% (w/w) of ionic liquid functionalized graphene, 2.72% (w/w) of zinc oxide, 1.82% (w/w) of stearic acid, 0.82% (w/w) of N- tert-butyl-benzothiazole sulfonamide (TBBS), and 1.36% (w/w) of sulphur.

In embodiments of the present disclosure, while the ionic liquid functionalized graphene at about 0.01% to about 18% is the concentration of the overall reinforcing filler (ionic liquid functionalized graphene), the ionic liquid is itself present in the composition at a concentration ranging from about 0.01% to about 5%. The presence of the ionic liquid at this concentration alters the curing or vulcanization kinetics by functionalizing the graphene and provides the ionic liquid functionalized graphene as the reinforcing filler in the final composition. The concentration of said ionic liquid functionalized graphene in the final composition is about 0.01% to about 18%.

In an exemplary embodiment of the present disclosure, ionic liquid employed in present composition and process ranges from about 0.01% to about 5% (w/w).

As mentioned above, the present disclosure either provides a composition comprising only the ionic liquid functionalized graphene as reinforcing filler or a composition comprising the ionic liquid functionalized graphene in addition to other reinforcing fillers. In such a case where both ionic liquid functionalized graphene and other reinforcing fillers form the filler component, in non-limiting embodiments, the concentration of said graphene in the filler component ranges from about 2% to about 10%, and that of other reinforcing fillers ranges from about 25% to about 70%.

As described in the above embodiments, while the concentration of ionic liquid functionalized graphene ranges from about 0.01% to about 18%, the at least one rubber forming part of the composition including but not limited to styrene-butadiene rubber (SBR), polybutadiene rubber (PBR), butyl rubber, halo butyl rubber, ethylene propylene diene methylene rubber (EPDM), silicone rubber and natural rubber, is at a concentration ranging from about 10% to about 95%.

Thus, in a non-limiting embodiment, the present disclosure provides a composition comprising at least one rubber including but not limited to styrene-butadiene rubber (SBR), polybutadiene rubber (PBR), butyl rubber, halo butyl rubber, ethylene propylene diene methylene rubber (EPDM), silicone rubber and natural rubber, at a concentration ranging from about 10% to about 95%, along with ionic liquid functionalized graphene at a concentrating ranging from about 0.01% to about 18%, as a reinforcing filler, optionally along with other additive(s).

As mentioned above, the composition of the present disclosure is a typical tyre composition that comprises all conventional ingredients known to be a part of or constitute a tyre, with an inclusion of ionic liquid functionalized graphene as a reinforcing filler. Accordingly, apart from the rubber and the reinforcing filler, the tyre composition of the present disclosure comprises additive components including but not limited to plasticizers, chemicals, metal reinforcements, textile reinforcements, additives, zinc oxide, sulphur, processing oil, accelerator, stearic acid and anti-oxidant. In an exemplary embodiment, typical concentration of these components are as follows: processing oil between 1 to 8 parts, stearic acid between 1 to 5 parts, antioxidant between 0.25 to 5 parts, zinc oxide between 1 to 6 parts and accelerator between 1 to 5 parts.

As mentioned previously, the inclusion of ionic liquid functionalized graphene as a reinforcing filler enhances or improves the magic triangle of tyre technology, which includes properties such as rolling resistance, abrasion resistance and wet grip of the tyre, along with other properties including but not limited to tensile modulus, fatigue failures, heat build-up, tear strength and better dispersion. The properties are enhanced or improved in tyre compositions where traditional reinforcing fillers, such as carbon black, are replaced completely or partially by the ionic liquid functionalized graphene, or where said graphene is included in addition to said traditional reinforcing fillers. The functionalization with ionic liquid also increases the cross-link density of the graphene-elastomer composites and improves their resistance to weather aging.

In a non-limiting embodiment, the tyre composition of the present disclosure comprising ionic liquid functionalized graphene as the reinforcing filler reduces the rolling resistance of a tyre by at least about 3% to about 25%.

In another non-limiting embodiment, the tyre composition of the present disclosure comprising ionic liquid functionalized graphene as the reinforcing filler reduces the abrasion loss (or increases the abrasion resistance) of a tyre by at least about 5% to about 40%.

In another non-limiting embodiment, the tyre composition of the present disclosure comprising ionic liquid functionalized graphene as the reinforcing filler reduces the weight of tread by at least about 10% to about 30%. This reduction in weight of the tread translates into reduction in overall weight of the tyre and adds to better fuel efficiency.

In another non-limiting embodiment, the tyre composition of the present disclosure comprising ionic liquid functionalized graphene as the reinforcing filler increases the tensile modulus of a tyre by at least about 10% to about 40%.
In another non-limiting embodiment, the tyre composition of the present disclosure comprising ionic liquid functionalized graphene as the reinforcing filler reduces the fatigue failure of a tyre by at least about 40%.

In another non-limiting embodiment, the tyre composition of the present disclosure comprising ionic liquid functionalized graphene as the reinforcing filler reduces the heat build-up of a tyre by at least about 2% to about 15%.

In another non-limiting embodiment, the tyre composition of the present disclosure comprising ionic liquid functionalized graphene as the reinforcing filler also helps in energy consumption by reducing the processing temperature.

As part of the present disclosure, in a tyre composition of typical natural rubber and SBR used widely in industries, when ionic liquid functionalized graphene replaces a minimum of 3 parts and a maximum of 15 parts of high abrasion furnace carbon black such as N330, desired properties of the resulting tyre are enhanced.

Thus, in an exemplary embodiment, when about 5 parts to about 10 parts of carbon black are replaced with every part of ionic liquid functionalized graphene in a tyre composition, the rolling resistance of the tyre is reduced by about 3% to about 25%, when compared to an identical composition containing only carbon black as the filler.

In another exemplary embodiment, when about 5 parts to about 10 parts of carbon black are replaced with every part of ionic liquid functionalized graphene in a tyre composition, the abrasion loss of the tyre is reduced (or the abrasion resistance is increased) by at least about 5% to about 40%, when compared to an identical composition containing only carbon black as the filler.

In yet another exemplary embodiment, when carbon black is replaced with ionic liquid functionalized graphene in a tyre composition, the weight of the tyre is reduced by at least about 10% to about 30%, when compared to an identical composition containing only carbon black as the filler.

In yet another exemplary embodiment, when about 5 parts to about 10 parts of carbon black are replaced with every part of ionic liquid functionalized graphene in a tyre composition, the tensile modulus of the tyre is increased by at least about 10% to about 40%, when compared to an identical composition containing only carbon black as the filler.

In yet another exemplary embodiment, when about 2.5 parts to about 10 parts of carbon black are replaced with same parts of ionic liquid functionalized graphene in a tyre composition, the fatigue failure of the tyre is reduced by at least about 40%, when compared to an identical composition containing only carbon black as the filler.

In yet another exemplary embodiment, when about 2.5 parts to about 10 parts of carbon black are replaced with same parts of ionic liquid functionalized graphene in a tyre composition, the heat build-up of the tyre is reduced by at least about 2% to about 15%, when compared to an identical composition containing only carbon black as the filler.

In yet another exemplary embodiment, when carbon black is replaced with ionic liquid functionalized graphene in a tyre composition, the wet grip of the tyre is increased by at least about 10%, when compared to an identical composition containing only carbon black as the filler.

As mentioned previously, the functionalization of graphene with ionic liquid, as provided by the present disclosure remedies the decrease in curing/vulcanizing time otherwise caused by inclusion of the unmodified graphene in a tyre composition. The present disclosure accordingly provides a corresponding process that allows such functionalization of graphene to produce ionic liquid functionalized graphene during preparation of the composition of the present disclosure.

The present process of preparing tyre composition is also important because conventional techniques such as melt processing technology do not allow incorporation of graphene in a composition that can be used to manufacture tyres. Graphene being fluffy and difficult to handle, a process that allows inclusion of graphene in compositions that are used for manufacturing of tyres, is important. The present disclosure accordingly provides for a functionalized graphene and a process thereof, that can be homogenously dispersed into elastomer matrix by conventional mechanical melt blending method or solution route followed by subsequent coagulation.

Accordingly, the present disclosure provides a process for preparing the tyre composition comprising mixing graphene, rubber/elastomer, ionic liquid and additive.

In embodiments of the present process, the mixing comprises high shear mixing at about 2500 RPM to 4500 RPM.

In other embodiments of the present process, the mixing comprises mixing in an internal mixer at 30 RPM to 120 RPM.

In preferred embodiments of the present process, the process of preparing tyre composition comprises:
a) mixing graphene with a solvent to form a graphene mixture, and
b) adding rubber, ionic liquid and additive to the graphene mixture, and mixing to prepare the composition.

In another preferred embodiment of the present process, the process of preparing tyre composition comprises:
a) melt-mixing of graphene and rubber to form a mixture; and
b) adding ionic liquid and additive to the mixture, and mixing to prepare the composition.

In some embodiments of the present process, a conventional filler (additive) is optionally added during the above mixing procedure in step a) or step b). In an embodiment, said filler is selected from a group comprising carbon black, silica, clay, graphene and combinations thereof.

In embodiments of the present process, the above mixing in step a) is high shear mixing carried out at about 2500 RPM to 4500 RPM. In other embodiments of the present process, the mixing in step b) in internal mixer at about 30 RPM to 120 RPM, preferably 60 RPM.

In embodiments of the present process, the solvent employed in above step a) is selected from a group comprising toluene, n-heptane, water, hexane, and combinations thereof.

In embodiments of the present process, the mixing in internal mixer in the step b) of the above described process is carried out at a temperature ranging from about 60°C to about 140°C in an internal mixer by melt mixing route at a rpm ranging from about 30 RPM to about 120 RPM, preferably about 60 RPM.

In a non-limiting embodiment, the mixing in internal mixer in the step b) of the above described process of the present disclosure is carried out at about 60°C at 60 RPM.

In some embodiments of the present process, it is during this mixing in the internal mixer that ionic liquid at a concentration ranging from about 0.01% to about 5% is added to facilitate functionalization of the graphene in the mixture. This alters the curing/vulcanization time of the rubber so prepared and the curing time can be altered, by changing the ionic liquid content. In exemplary embodiments, the ionic liquid results in an increase in curing rate by at least 100%.

In another preferred embodiments of the present process, the process of preparing tyre composition comprises mixing all the components viz. rubber, graphene, ionic liquid and additives together in-situ to prepare the composition.

In embodiments of the present process, the above described processes are carried out at a temperature between 60°C to 150°C, and for a time-period ranging from about 20 minutes to 2 hours.

The present disclosure thus provides a solution-based master batch process for production of the composition of the present disclosure. By this method, about 0.01% to about 18% of ionic liquid functionalized graphene can be incorporated in a tyre composition, either in place of conventional fillers such as carbon black, or in addition to such existing fillers.

In an exemplary embodiment, the present process comprises steps including but not limited to mixing of the graphene with a combination of solvents followed by adding the mixture to a combination of one or more rubbers/ elastomers employed for preparing a tyre composition. Once mixed, a different type of solvent is used to coagulate the rubber(s) or elastomer(s) from the mixture, to obtain a layered compound-rubber/elastomer master batch, which is then used for manufacturing of tyres/preparing tire tread formulations.

While the conventional melt processing allows only a maximum of about 2.5 parts of high surface area graphene to be incorporated in a composition without external processing aid, a higher amount, up to a maximum of about 15 parts of graphene can be mixed when it is functionalized with ionic liquid.

In an exemplary embodiment, the process of the present disclosure comprises steps including but not limited to mixing of graphene as a master batch in a high shear mixer with a combination of one or more rubbers employed for preparing the tyre composition of the present disclosure.

In a non-limiting embodiment of the present disclosure, the graphene master batch is prepared by mixing the graphene with a combination of solvents in a high shear mixer for a time duration ranging from about 20 minutes to about 60 minutes. Preferably, the mixing is for about 60 minutes. This mixture is thereafter added to the combination of one or more rubbers/elastomers employed for preparing a tyre composition.

Since the most commonly used rubber is styrene-butadiene copolymer/rubber (SBR), in an embodiment of the disclosure, the process involves mixing of the graphene via a masterbatch of PBR or NR or a combination, with said rubber (SBR) for preparing the tyre composition. In a non-limiting embodiment, in tyre composition where the rubber employed is different from the said copolymer, the graphene is mixed via a masterbatch. For example, if the rubber employed are styrene-butadiene rubber (SBR) and polybutadiene rubber (PBR), the graphene is first mixed with PBR to form a masterbatch, post which, the SBR is mixed with the said combination in the internal mixer. Once the graphene and the rubber are mixed, other ingredients/components (additives) are subsequently added in the final formulation.

In the process of the present disclosure, the ionic liquid used for functionalizing graphene include but are not limited to those comprising anions including but not limited to bromide, chloride, tetrafluoroborate, and hexafluorophosphate. Further, the ionic liquid used for functionalizing graphene also include but are not limited to those comprising long chain aliphatic cationic groups. In a non-limiting embodiment, these alkyl chains include allyl-, ethyl-, butyl-, hexyl-, and octyl- chains.

In an exemplary embodiment, the ionic liquid used for functionalizing graphene includes but is not limited to alkylimidazolium salts, alkylpyridinium salts and alkylpyrrolidinium salts.
In an exemplary embodiment the composition and process of the present disclosure, the ionic liquid used for functionalizing graphene is trihexyltetradecylphosphonium bromide.

Accordingly, the process of the present disclosure allows incorporation of the ionic liquid functionalized graphene to prepare the composition of the present disclosure, which improves the properties of the tyre manufactured therefrom.

The present disclosure accordingly also relates to use of the composition described herein comprising the ionic liquid functionalized graphene as a reinforcing filler for manufacturing of tyres. Corresponding tyre products obtained therefrom are also a part of the present disclosure.

In a non-limiting embodiment, the tyres manufactured using the composition of the present disclosure having graphene, display enhanced properties compared to tyres manufactured by a composition devoid of ionic liquid functionalized graphene. These properties include but are not limited to weight of the tyre, fuel efficiency, tensile modulus, rolling resistance, abrasion loss, fatigue failure, and heat build-up.

In an exemplary embodiment, the tyres manufactured using the composition of the present disclosure display reduction in weight by about 10% to about 30%, reduction in rolling resistance by about 3% to about 25%, reduction in abrasion loss (or increase in abrasion resistance) by about 5% to about 40%, increase in tensile modulus by about 10% to about 40%, reduction in fatigue failure by about 40%, and reduction in the heat build-up by about 2% to about 15%.

Thus, in total, the present disclosure provides a tyre composition comprising ionic liquid functionalized graphene as a reinforcing filler that allows the tyre to display enhanced properties when compared to a tyre made of composition comprising conventionally used fillers, such as carbon black. In order to arrive at the said composition, the present disclosure also provides a process for incorporation of the ionic liquid functionalized graphene in the composition, such that the curing/vulcanization time of the resulting rubber is reduced when compared to a composition comprising non-functionalized graphene. The composition prepared in the present disclosure can accordingly be used for manufacturing of tyres, that display enhanced properties, performance and life.

While the instant disclosure is susceptible to various modifications and alternative forms, specific aspects thereof have been shown by way of examples and drawings and are described in detail below. However, it should be understood that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and the scope of the invention as defined by the appended claims.

EXAMPLES
The present disclosure is further described with reference to the following examples, which are only illustrative in nature and should not be construed to limit the scope of the present disclosure in any manner.

Before describing the experiments conducted in detail, it is noted that for the purposes of showcasing enhanced effect of the composition of the present disclosure, comparison was made with compositions comprising conventionally employed filler, such as carbon black; and/or compositions comprising graphene (non-functionalized graphene). Further, compositions comprising conventionally employed filler, such as carbon black was prepared by conventional methods, briefly, wherein carbon black used as a filler was mixed with rubber elastomers employed for the preparation of the tyre composition. Upon mixing of the carbon black with individual elastomers, the mixtures were combined and further mixed together in an internal mixer at about 60°C at about 60 rpm.

Example 1
General procedure for preparation of the tyre composition of the present disclosure
Graphene master batch was prepared with about 2% to about 15% graphene. Briefly, the graphene was mixed with a solvent (single solvent or a combination of solvents) in a high-shear mixer at about 2500 rpm to 4500 rpm for a time duration ranging from about 20 minutes to about 1 hour.

Separately, a rubber mixture comprising a single rubber (such as SBR or PBR), or a combination of rubbers (such as SBR and PBR) was prepared.

The graphene master batch was mixed with the rubber, the ionic liquid (0.1% to 0.5% of ionic liquid), and other additive ingredients/components in the internal mixer and mixing at about 60 rpm was carried out at a temperature range of about 60°C to 140°C by melt mixing route, to obtain the composition of the present disclosure.

Example 2
Preparation of various tyre compositions of the present disclosure
Several compositions according to the present disclosure were prepared. The procedure employed was as follows:

A) Procedure for incorporation of graphene in PBR
Step 1: Dispersion of Graphene by high shear process
About 6500 mL of dry solvent (Toluene and N-Heptane mixture at 55:45) was taken in SS container and about 30 gm graphene was added to it. The solution mixture was mixed in high shear mixer for about 1 hour at about 4000 RPM or at about 2500 RPM. The process condition was checked frequently after every 30 minutes.

Step 2: Incorporation of graphene in PBR cement
About 5000 gm fresh PBR cement was added into the graphene mixture obtained in step 1. The shear mixer speed was kept at about 4000 RPM in L5M-A type or at about 2500 RPM in AX5 type silverson. The solution mixture was kept under shear for about 1 hour.

Step 3: Coagulation process
After an hour, the stirrer was stopped and about 10500 mL isopropyl alcohol (IPA) solvent was slowly added to the graphene-PBR batch obtained in step 2 until black PBR elastomer separates out from the clear solution. Excess solvent was removed by using filter and then by squeezing from the black PBR elastomer. The black PBR elastomer was used for two roll mill process.

Step 4: Two roll milling
Two roll mill process was performed in a two-roll mill. The roll nip opening was set at 2.5 mm and temperature was set at about 110°± 5°C. The rubber (black PBR elastomer obtained in step 3) was added into the mill nip and band, as a continuous sheet, onto the front roll. Using a hand knife, about 2-3 cuts from each side were made and the rubber was allowed to move through the nip gap quite a few times until a smooth rolling bank was formed on the nip. Since solvent evaporation occurs during two roll milling process, the area was properly ventilated and scrubber was used for proper disposal of solvent vapours.

B) Procedure for incorporation of ionic liquid and additives in the mixture prepared in Example 2A
Step 1: Addition of ionic liquid and other rubber processing chemicals (additives)
For addition of other ingredients, first, the batch weight of the rubber-graphene elastomer was calculated according to the fill factor. The graphene containing PBR mixture obtained in Example 2A, raw SBR and/or other rubbers (if employed), other raw materials (additives) and ionic liquid were weighed as per the recipe and charged into a mixing chamber (internal mixer) that is set at 60°C in TCU for 60 rpm. For ease of mixing, the elastomer sample was cut into thin strips of about 1-2 inch width and 5-6 inch length and charged in the mixing chamber after reaching the temperature.

The ram was raised and the chemicals (additives except sulphur and accelerator) and ionic liquid were added into the chamber, post which the ram was lowered. The batch was allowed to cool for a minimum of 4 hrs in air before proceeding with second-stage mix.

In the second stage, the initial temperature was kept at about 70°C in TCU for about 45 rpm. The material obtained at the previous step was cut into thin strips of about 1-2 inches width and 5-6 inches length and charged in the mixing chamber after reaching the temperature. The ram was raised, and sulphur and accelerator were added into the mixing chamber, post which the ram was lowered again. Mixing was performed for a total of about 180 seconds. Maximum allowable temperature limit is about 95°C. After mixing, the ram was raised and discharge door was opened. The batch was kept in a tray and dump temperature was recorded. The batch weight was measured and recorded. The batch was allowed to cool for minimum of about 4 hrs before proceeding for testing.

Example 3
Testing of the tyre compositions for curing time and physical properties
Several compositions of the present disclosure and conventional/comparative compositions were prepared. Said compositions and their respective curing time and physical properties are provided below:

Table 1 below provides PBR and SBR based compositions comprising no filler, carbon black as filler, graphene as a filler (without ionic liquid functionalization), and ionic liquid functionalized graphene as the reinforcing filler.
Components Gum Compound without filler Control Composition [Carbon Black (N330) filler] Composition comprising Graphene filler Present Composition comprising Graphene with Ionic Liquid (ionic liquid functionalized graphene)
Raw SBR 1502 (HMD) 70.00 phr
(65.57 wt%) 70.00 phr
(55.23 wt%) 70.00 phr
(64.07 wt%) 70.00 phr
(63.93 wt%)
Raw PBR CISAMER 01 30.00 phr
(28.11 wt%) 30.00 phr
(23.66 wt%) 7.50 phr
(6.86 wt%) 7.50 phr
(6.85 wt%)
PBR master batch 0.00
(0 wt%) 0.00
(0 wt%) 22.50 phr
(20.60 wt%) 22.50 phr
(20.55 wt%)
Carbon Black (N330) 0.00
(0 wt%) 20.00 phr
(15.78 wt%) 0.00
(0 wt%) 0.00
(0 wt%)
Graphene 0.00
(0 wt%) 0.00
(0 wt%) 2.5 phr
(2.29 wt%) 2.5 phr
(2.28 wt%)
Ionic Liquid
(trihexyltetradecylphosphonium bromide) 0.00
(0 wt%) 0.00
(0 wt%) 0.00
(0 wt%) 0.25 phr
(0.23 wt%)
ZnO 3.00 phr
(2.81 wt%) 3.00 phr
(2.37 wt%) 3.00 phr
(2.75 wt%) 3.00 phr
(2.74 wt%)
Stearic Acid 1.00 phr
(0.94 wt%) 1.00 phr
(0.79 wt%) 1.00 phr
(0.91 wt%) 1.00 phr
(0.91 wt%)
TBBS 1.00 phr
(0.94 wt%) 1.00 phr
(0.79 wt%) 1.00 phr
(0.91 wt%) 1.00 phr
(0.91 wt%)
Soluble Sulphur 1.75 phr
(1.63 wt%) 1.75 phr
(1.38 wt%) 1.75 phr
(1.61 wt%) 1.75 phr
(1.60 wt%)
Total PHR / wt% 106.75 phr
(100 wt%) 126.75 phr
(100 wt%) 109.25 phr
(100 wt%) 109.50 phr
(100 wt%)
Table 1: PBR and SBR based Compositions

The aforesaid compositions of Table 1 were subjected to rheological measurements through ASTM D5289 protocol (Table 2) by moving die rheometer at 160°C for about 30 minutes. These measurements were carried out to measure the following:
i) ML (Minimum Torque): As the compound gets heated under pressure, the viscosity decreases and the torque falls. The lowest value of torque is recorded as ML. Basically, it is a measure of the stiffness and viscosity of unvulcanized compound.
ii) MH (Maximum Torque): As the curing starts, the torque increases proportionately. Depending upon the type of compound, the slope of rising torque varies. After a while the torque typically attains maximum value and it plateaus out. It is called “Plateau Curve”. If test is continued for sufficient time, the reversion of cure occurs and torque tends to fall. This type of curve with reversion is called “Reverting Curve”. At times the torque shows continuous rising trend during the period of record. Such type of curve is called “Rising or Marching Curve”. MH (Max. torque) is the highest torque recorded in plateau curve. In reverting curve, the Max. torque recorded is abbreviated as MHR.
iii) Ts’X’ (Scorch time): After attaining minimum torque, during cure phase, as the torque rises, Ts is scorch time for viscosity to rise X units above ML. Scorch is premature vulcanization in which the stock becomes partly vulcanized before the product is in its final form and ready for vulcanization. It reduces the plastic properties of the compound so that it can no longer be processed. Scorching is the result of both the temperatures reached during processing and the amount of time the compound is exposed to elevated temperatures. This period before vulcanization starts is generally referred to as “Scorch time”. Since scorching ruins the stock, it is important that vulcanization does not start until processing is complete.
iv) Tc’X’ (Cure time): It is the time at which X% of cure has taken place.

Table 2: Evaluation of Curing Time/Rate
Parameter Gum Compound without filler Control Composition [Carbon Black (N330) filler] Composition comprising Graphene filler Present Composition comprising Graphene with Ionic Liquid (ionic liquid functionalized graphene)
ML (dN-M) 0.87 1.45 1.56 1.51
MH (dN-M) 9.75 14.34 15.1 16.74
Ts1 (Min) 10.85 4.61 4.29 2.12
Ts2 (Min) 12.17 5.8 5.93 2.65
TC10 (Min) 10.58 5.12 5.1 2.47
TC25 (Min) 12.36 6.4 6.76 3.04
TC40 (Min) 13.34 7.13 7.52 3.36
TC50 (Min) 13.97 7.64 8 3.6
TC90 (Min) (Curing Time) 19.96 12.49 12.36 6.26
Final Tq.(dN-M) 9.73 14.25 13.54 16.33
Delta Tq.(dN-M) 8.88 12.89 14.94 15.23
Cure Rate 1.14 1.93 2.32 4.22

The said compositions of Table 1 were also subjected to measurements for testing their physical properties through ASTM D412 protocol (Table 3) at 160°C for t90 + 2 minutes. These measurements were carried out to measure the following:
(i) Modulus at specific (X%) elongation in MPa.
(ii) Tensile strength in MPa.
(iii) Elongation at break (%).
(iv) Hardness.

Table 3: Evaluation of Physical Properties
Parameter Gum Compound without filler Control Composition [Carbon Black (N330) filler] Composition comprising Graphene filler Present Composition comprising Graphene with Ionic Liquid (ionic liquid functionalized graphene)
Mod @100% Elong. (MPa) 1.1 1.8 2.6 3
Mod @200% Elong.(MPa) 1.8 3.7 5.2 6.2
Mod @300% Elong.(MPa) 0 6.7 8 0
Elong @ Brk. (%) 267 415 331 255
Hardness (Shore A) 42 53 55 56

The above results show that by addition of ionic liquid, there is an increase (or no change) in the hardness of the present composition comprising ionic liquid functionalized graphene when compared to the compositions comprising graphene or carbon black filler.

Also, the features of rolling resistance and heat build-up of the aforesaid compositions of Table 1 were tested [DMA Temp Sweep [(10Hz/1% dynamic strain/2% static strain)]. The results are provided in Table 4 below.

Table 4: Rolling resistance and Heat build-up properties
Parameter Gum Compound without filler Control Composition [Carbon Black (N330) filler] Composition comprising Graphene filler Present Composition comprising Graphene with Ionic Liquid (ionic liquid functionalized graphene)
tan delta, 30? temp 0.074 0.105 0.090 0.080
tan delta, 70? temp 0.052 0.08399801 0.07284384 0.060
tan delta, 100? temp 0.038 0.06689298 0.05828409 0.047

Tan d @ 60°C is a measure of rolling resistance. Lower the value, lower is the rolling resistance. The present composition shows ~13% to ~28% lower rolling resistance compared to compositions comprising carbon filler or graphene, respectively, which is a significant advantage. Tan d @ 100°C is a measure of heat build-up. Lower the value, lower is the heat build-up. The present composition shows ~13% to ~30% lower heat build-up compared to compositions comprising carbon filler or graphene, respectively, which is a significant advantage.

Table 5 below provides PBR based compositions comprising no filler, carbon black as filler, graphene as a filler (without ionic liquid functionalization), and compositions comprising ionic liquid functionalized graphene as the reinforcing filler. Features of curing time/rate, physical properties rolling resistance & heat build-up of said compositions of Table 5 are further tabulated in Tables 6, 7 and 8, respectively.

Table 5: PBR based Compositions
Components Gum Compound without filler Control Composition [Carbon Black (N330) filler] Composition comprising Graphene filler Present Composition 1 comprising Graphene with Ionic Liquid (ionic liquid functionalized graphene) Present Composition 2 comprising Graphene with Ionic Liquid (ionic liquid functionalized graphene)
PBR 01 100.00 phr
(93.11 wt%) 100.00 phr
(78.49 wt%) 100.00 phr
(91.00 wt%) 100.00 phr
(90.58 wt%) 100.00 phr
(90.78 wt%)
Carbon Black (N330) 0.00 phr
(0 wt%)
20.00 phr
(15.70 wt%) 0.00 phr
(0 wt%) 0.00 phr
(0 wt%) 0.00 phr
(0 wt%)
Graphene 0.00 phr
(0 wt%) 0.00 phr
(0 wt%) 2.50 phr
(2.27 wt%) 2.50 phr
(2.26 wt%) 2.50 phr
(2.27 wt%)
Ionic Liquid
(trihexyltetradecylphosphonium bromide) 0.00 phr
(0 wt%) 0.00 phr
(0 wt%) 0.00 phr
(0 wt%) 0.50 phr
(0.45 wt%) 0.25 phr
(0.23 wt%)
ZnO 3.00 phr
(2.80 wt%) 3.00 phr
(2.35 wt%) 3.00 phr
(2.73 wt%) 3.00 phr
(2.72 wt%) 3.00 phr
(2.73 wt%)
Stearic Acid 2.00 phr
(1.86 wt%) 2.00 phr
(1.57 wt%) 2.00 phr
(1.82 wt%) 2.00 phr
(1.81 wt%) 2.00 phr
(1.82 wt%)
TBBS 0.90 phr
(0.84 wt%) 0.90 phr
(0.71 wt%) 0.90 phr
(0.82 wt%) 0.90 phr
(0.82 wt%) 0.90 phr
(0.81 wt%)
Soluble Sulphur 1.50 phr
(1.39 wt%) 1.50 phr
(1.18 wt%) 1.50 phr
(1.36 wt%) 1.50 phr
(1.36 wt%) 1.50 phr
(1.36 wt%)
Total PHR / wt % 107.40 phr
(100 wt%) 127.40 phr
(100 wt%) 109.90 phr
(100 wt%) 110.40 phr
(100 wt%) 110.15 phr
(100 wt%)

Compositions were developed comprising ionic liquid at different concentrations/amounts as shown in Table 5. It was observed that change in the ionic liquid content alters the curing/vulcanization time of the rubber so prepared. As shown in Table 6 below, compositions of Table 5 with ionic liquid content of 0.25 phr showed an increase in curing rate by 4.4 times, and at an ionic liquid content of 0.5 phr showed a further increase in curing rate of 4.5 times when compared to composition containing only graphene filler.

Table 6: Evaluation of Curing Time/Rate
Components Gum Compound without filler Control Composition [Carbon Black (N330) filler] Composition comprising Graphene filler Present Composition 1 comprising Graphene with Ionic Liquid (ionic liquid functionalized graphene) Present Composition 2 comprising Graphene with Ionic Liquid (ionic liquid functionalized graphene)
Rheo Study (MDR 2000) @160°C / 45 min
ML(dN-M) 1.82 0.98 1.08 1.06 1.07
MH(dN-M) 10.42 6.43 6.84 9.42 9.06
Ts1 (Min) 5.81 13.95 11.5 2.56 3.6
Ts2 (Min) 6.83 15.29 13.26 2.96 4.05
TC10 (Min) 5.46 12.37 10.09 2.45 3.45
TC25 (Min) 6.92 14.54 12.36 2.99 4.04
TC40 (Min) 7.62 15.5 13.73 3.28 4.35
TC50 (Min) 8.07 16.12 14.54 3.44 4.53
TC90 (Min) 11.48 21.13 20.25 5.24 6.27
Final Tq.(dN-M) 9.15 6.2 6.69 8.18 7.83
Delta Tq.(dN-M) 8.6 5.45 5.76 8.36 7.99
Cure Rate 1.85 0.93 0.82 3.67 3.60

As seen above, the curing time and curing rate are significantly improved when ionic liquid functionalized graphene is used in tyre compositions. In addition, the physical properties are also significantly improved when graphene incorporated in the compositions is functionalized with ionic liquid as shown in Table 7.

Table 7: Evaluation of Physical Properties
Parameter Gum Compound without filler Control Composition [Carbon Black (N330) filler] Composition comprising Graphene filler Present Composition 1 comprising Graphene with Ionic Liquid (ionic liquid functionalized graphene) Present Composition 2 comprising Graphene with Ionic Liquid (ionic liquid functionalized graphene)
Mod @100% Elong. (MPa) 1.3 0.9 0.8 1.2 1.2
Mod @200% Elong. (MPa) 2.4 1.5 1.3 0 0
Mod @300% Elong. (MPa) 4.2 0 0 0 0
Elong @ Brk. (%) 367.1 284 296 176 187
Hardness (Shore A) 43 36 33 39 39

The above results show that by addition of ionic liquid, there is an increase (or no change) in the hardness of the present composition comprising ionic liquid functionalized graphene when compared to the compositions comprising graphene or carbon black filler.

Additionally, the features of rolling resistance and heat build-up of the aforesaid composition 2 comprising ionic liquid functionalized graphene of Table 5 were tested [DMA Temp Sweep [(10Hz/1% dynamic Strain/2 %static strain)]. The results are provided in Table 8 below.

Table 8: Rolling resistance and Heat build-up properties
Parameter Gum Compound without filler Present Composition 2 comprising Graphene with Ionic Liquid (ionic liquid functionalized graphene)
tan delta, 0? temp 0.144 0.082
tan delta, 30? temp 0.132 0.073
tan delta, 70? temp 0.115 0.062
tan delta, 100? temp 0.105 0.057

Tan d @ 60°C is a measure of rolling resistance. Lower the value, lower is the rolling resistance. The present composition shows ~ 46% lower rolling resistance compared to composition having no filler, which is a significant advantage. Tan d @ 100°C is a measure of heat build-up. Lower the value, lower is the heat build-up. The present composition shows ~ 46% lower heat build-up compared to composition comprising no filler or graphene, which is a significant advantage.

Further, when final graphene content in the formulation exceeds 3 phr, the results achieved in terms of rolling resistance were inferior. Following experiments (Table 9) were performed which confirms said fact.

Table 9: Effect of increase in Graphene content
Components Composition 1 Comparison
Composition 1 Comparison
Composition 2
Raw SBR 1502 70.00 phr
(63.78 wt%) 70.00
(63.21 wt%) 70.00
(62.64 wt%)
Raw PBR CISAMER 01 3.00 phr
(2.73 wt%) 3.00
(2.71 wt%) 3.00
(2.69 wt%)
PBR masterbatch (contains 27 phr/ 90 wt% PBR and 3 phr/ 10 wt% Graphene) 30.00 phr
(27.34 wt%) 30.00
(27.09 wt%) 30.00
(26.85 wt%)
Additional graphene added during melt-mixing 0.00 phr
(0 wt%)
1.00 phr
(0.90 wt%) 2.00 phr
(1.79 wt%)
Carbon Black (N330) 0.00 phr
(0 wt%)
0.00 phr
(0 wt%)
0.00 phr
(0 wt%)

ZnO 3.00 phr
(2.73 wt%) 3.00 phr
(2.71 wt%) 3.00 phr
(2.68 wt%)
Stearic Acid 1.00 phr
(0.91 wt%) 1.0 phr
(0.90 wt%) 1.0 phr
(0.89 wt%)
TBBS 1.0 phr
(0.91 wt%) 1.0 phr
(0.90 wt%) 1.0 phr
(0.89 wt%)
Soluble Sulphur 1.75 phr
(1.60 wt%) 1.75 phr
(1.58 wt%) 1.75 phr
(1.57 wt%)
Total PHR / wt% 109.75 phr
(100 wt%) 110.75 phr
(100 wt%) 111.75 phr
(100 wt%)

DMA Temp Sweep (10Hz / 1% dynamic Strain/2% static strain)
tan delta , 30C temp 0.10 0.10 0.10
tan delta , 70C temp 0.09 0.09 0.10
tan delta , 100C temp 0.07 0.08 0.08

Tangent delta values provided in above Table 9 is a measure of rolling resistance. Lower the value, better is the rolling resistance. The results show that the values increase with increase in graphene amount which indicates deteriorating/inferior rolling resistance. It was also found that while all the experiments of Table 9 were performed with 10% graphene in the PBR masterbatch, any concentration of graphene beyond 18% in the masterbatch makes it hard and renders it processable.

Similar to the above results, additional tyre compositions comprising ionic liquid functionalized graphene within the purview of the subject-matter/embodiments described herein with respect to various rubber and ionic liquid compounds can be prepared. Further, tyre compositions comprising different ionic liquids are expected to show similar properties as discussed in the above examples. This is also considering the fact that all ionic liquids share a similar behavior. In particular, the ionic liquids have two parts i.e. cation and anion, wherein both parts can affect the curing process of the elastomer. Further, ionic liquids, preferably higher alkyl group containing ionic liquids when employed would result in faster curing in terms of curing time and curing rate.

ADVANTAGES/BENEFITS
The compositions and methods of the present disclosure provides advantages including but not limiting to the following:
(a) the presence of ionic liquid functionalized graphene in the tyre compositions lead to improved efficiency/properties when compared to compositions containing conventional fillers such as carbon black or graphene. Such properties include rolling resistance, abrasion resistance and wet grip of the tyre, along with other properties including but not limited to tensile modulus, fatigue failures, heat build-up, tear strength and better dispersion.
(b) the presence of ionic liquid functionalized graphene significantly lowers the curing time/curing rate while synthesis of tyres when compared to conventional fillers such as carbon black or graphene. This is a very important advantage of the ionic liquid functionalized graphene of the present invention.
(c) the ionic liquid employed for functionalization of graphene resulting in ‘ionic liquid functionalized graphene’ is an integral part/component of the composition described herein. Said ionic liquid compound functions as a functionalization agent for obtaining “functionalized graphene” which acts as reinforcing filler (and not as a solvent or other material which merely takes part in the preparation process or leads to the formation of exfoliated graphene).
(d) the preparation/formation of functionalized graphene and subsequently the final rubber polymer matrix by high shear mixing when compared to the conventionally employed mixing steps/features is also an advantage in terms of obtaining an improved tyre composition/product. In particular, the presently described method is a simple one-step melt mixing for functionalization with ionic liquid and addition of graphene into elastomer/rubber matrix. Tedious functionalization process through various chemical modification steps for the addition of graphene which may not be suitable for large scale production is avoided.
(e) the present process and composition employs very small amounts of ionic liquid for functionalization of graphene and to make the graphene amenable for incorporation into elastomer/rubber matrix.

Additional embodiments and features of the present disclosure will be apparent to one of ordinary skill in art based on the description provided herein. The embodiments herein provide various features and advantageous details thereof in the description. Descriptions of well-known/conventional methods and techniques are omitted so as to not unnecessarily obscure the embodiments herein.

The foregoing description of the specific embodiments fully reveals the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments in this disclosure have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising” wherever used, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

Any discussion of documents, acts, materials, devices, articles and the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.

While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other modifications in the nature of the disclosure or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.
,CLAIMS:We Claim:
1. A composition comprising a rubber and ionic liquid functionalized graphene.

2. The composition according to claim 1, wherein the rubber is at a concentration ranging from about 10% (w/w) to 95% (w/w) and the ionic liquid functionalized graphene is at a concentration ranging from about 0.01% (w/w) to about 18% (w/w).

3. The composition according to claim 1, wherein graphene reacts with ionic liquid to form the ionic liquid functionalized graphene.

4. The composition according to claim 1, wherein the ionic liquid comprises anions selected from a group comprising bromide, chloride, tetrafluoroborate, hexafluorophosphate, triflurosulfonamides, triflurosulfates, dicyanmides, tosylates, triflates and combinations thereof.

5. The composition according to claim 1, wherein the ionic liquid comprises cations selected from a group comprising long chain aliphatic cationic group, imidazolium derivatives, guanidiniums, ammonium, pyridinium, phosphonium, sulfonium, pyrrolidinium and combinations thereof.

6. The composition according to claim 5, wherein the long chain aliphatic cationic group comprises alkyl chains selected from a group comprising allyl-, ethyl-, butyl-, hexyl-, octyl-, decyl-, dodecyl-, hexadecyl-, octadecyl- chains and combinations thereof.

7. The composition according to claim 1, wherein the ionic liquid is selected from a group comprising trihexyltetradecylphosphonium bromide, alkyl imidazolium salt, alkyl pyridinium salt, alkyl pyrrolidinium salt, ammonium salt, pyridinium chloride, pyridinium bromide, tetrahexyl ammonium bromide, trihexyldecyl ammonium bromide, tetrahexyldecyl phosphonium bromide and combinations thereof.

8. The composition according to claim 1, wherein the rubber is selected from a group comprising styrene-butadiene rubber (SBR), polybutadiene rubber (PBR), butyl rubber (BR), halo butyl rubber, ethylene propylene diene methylene rubber (EPDM), silicone rubber, natural rubber (NR) and combinations thereof.

9. The composition according to claim 1, wherein the composition further comprises an additive selected from a group comprising filler, plasticizer, chemicals, metal reinforcements, textile reinforcements, processing oil, accelerator, anti-oxidant, and combinations thereof; and wherein said additive is at a concentration ranging from about 10% (w/w) to about 60% (w/w).

10. The composition according to claim 9, wherein the filler is selected from a group comprising carbon black, silica, clay, graphene and combinations thereof; the plasticizer is selected from a group comprising pre-crosslinked acrylonitrile co-polymer (CCF resin), wood resin, Coumarone-Indene resin (CI) and combinations thereof; the chemicals are selected from a group comprising vulcanization aids, vulcanizing agents and combinations thereof; the metal reinforcements is selected from a group comprising steel, high strength high carbon steel and combinations thereof; the textile reinforcements is selected from a group comprising polyamide , polyester and combinations thereof; the processing oil is selected from a group comprising aromatic oil, naphthenic oil, paraffinic oil and combinations thereof; the accelerator is selected from a group comprising N- tert-butyl-benzothiazole sulfonamide (TBBS), N-(1,3-Dimethylbutyl)-N’-phenyl-p-phenylenediamine (TBzTD), N-Cyclohexyl-2-benzothiazole sulfonamide (CBS) and combinations thereof; and the antioxidant is selected from a group comprising 2,2,4-Trimethyl-1,1-dihydroquinoline (TMQ), N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), phenolics and combinations thereof;
and wherein the vulcanization aid is selected from a group comprising zinc oxide, stearic acid and a combination thereof, and the vulcanizing agent is sulphur.

11. The composition according to claim 1, wherein the composition comprises about 64% (w/w) of styrene-butadiene rubber (SBR), about 27% (w/w) of polybutadiene rubber (PBR), about 2.6% (w/w) of ionic liquid functionalized graphene, about 2.8% (w/w) of zinc oxide, about 1% (w/w) of stearic acid, about 1% (w/w) of N- tert-butyl-benzothiazole sulfonamide (TBBS), and about 1.6% (w/w) of sulphur.

12. The composition according to claim 1, wherein the composition comprises about 90.6% (w/w) of polybutadiene rubber (PBR), about 2.8% (w/w) of ionic liquid functionalized graphene, about 2.7% (w/w) of zinc oxide, about 1.8% (w/w) of stearic acid, about 0.8% (w/w) of N- tert-butyl-benzothiazole sulfonamide (TBBS), and about 1.3% (w/w) of sulphur.

13. The composition according to claim 1, wherein the composition comprises 90.8% (w/w) of polybutadiene rubber (PBR), about 2.6% (w/w) of ionic liquid functionalized graphene, 2.7% (w/w) of zinc oxide, 1.8% (w/w) of stearic acid, 0.8% (w/w) of N- tert-butyl-benzothiazole sulfonamide (TBBS), and 1.3% (w/w) of sulphur.

14. A process for preparing the composition of claim 1 comprising mixing graphene, rubber, ionic liquid and additive to prepare the composition.

15. The process according to claim 14, wherein the mixing comprises high shear mixing.

16. The process according to claim 14, wherein the process comprises:
a) mixing graphene with a solvent to form a graphene mixture; and
b) adding rubber, ionic liquid and additive to the graphene mixture, and mixing to prepare the composition,
or
a) mixing graphene and rubber by melt-mixing to form a mixture; and
b) adding ionic liquid and additive to the mixture, and mixing to prepare the composition.

17. The process according to claim 16, wherein a conventional filler is optionally added, and wherein said filler is selected from a group comprising carbon black, silica, clay, and combinations thereof.

18. The process according to claim 16, wherein the mixing in step a) is high shear mixing carried out at about 2500 RPM to 4500 RPM, and the mixing in step b) is in internal mixer at about 30 RPM to 120 RPM; and wherein the solvent is selected from a group comprising toluene, n-heptane, water, hexane, and combinations thereof.

19. The process according to claim 14, wherein the process is carried out at a temperature between 60°C to 150°C, and for a time-period ranging from about 20 minutes to 2 hours.

20. A tyre product comprising the composition according to claim 1.