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 graphene as a reinforcing filler. The said composition when used for manufacturing tyres, lends enhanced properties and life to the tyre, when compared to a tyre manufactured using a composition comprising traditional fillers, such as carbon black. The disclosure also provides a corresponding process that allows incorporation of the said 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 foot print 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. However, handling of graphene in powder form is difficult due to its low bulk density and fluffy nature which prevents it from being stable and often flies off while mixing and possesses health hazard. Further, while prior literatures have tried to employ graphene in tyre compositions, it has been possible to mix up to a maximum of 10 parts of graphene only along with an external processing aid, e.g. mineral oils. Further, conventional melt processing only allows a maximum of only 2.5 parts of high surface area graphene to be incorporated in the formulations.
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, its impact on rolling resistance, abrasion loss, fatigue failures, and heat build-up must be tested. Accordingly, tyre compositions comprising varying amounts of graphene are desired for longer life of tyre tread and improved properties. However, none of the currently available processes allow stable incorporation of graphene in tyre compositions at specific amounts, and without substantial use of an external processing aid. Thus, there is a need to find alternative processes and compositions that improve the quality of tyres to achieve the desired results.
SUMMARY OF THE DISCLOSURE
The present disclosure relates to a tyre composition comprising graphene as a reinforcing filler. More specifically, the disclosure relates to a tyre composition comprising at least one rubber and graphene, wherein the graphene is at a concentration ranging from about 0.01% to about 3.5%.
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, along with graphene in form of a rubber masterbatch at a concentration ranging from about 0.01% to about 18%, as a reinforcing filler.
In embodiments of the present disclosure, the tyre composition herein is prepared by either completely or partially replacing a traditional reinforcing filler by graphene, or by adding the graphene 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.
The present disclosure also relates to a process for preparing the tyre composition of the present disclosure. More particularly, the process for preparing the tyre composition herein comprises steps of:
a. mixing graphene with at least one rubber in presence of at least one solvent in a high shear mixer at rpm ranging between 2500 and 4000, for a time duration ranging from about 20 minutes to about 60 minutes to obtain a rubber masterbatch; and
b. mixing the rubber masterbatch with same or different rubber, optionally along with additional component to obtain the said tyre composition.
In embodiments of the present disclosure, the process comprises mixing of the graphene with a combination of elastomers/rubbers that constitute the tyre.
The present disclosure also relates to a method of improving at least one property of a tyre selected from a group comprising rolling resistance, abrasion loss, tensile modulus, heat build-up and fatigue failure, or any combination thereof, said method comprising act of manufacturing the tyre by employing the tyre composition the present disclosure.
The present disclosure also relates to the use of the tyre composition for manufacturing of tyres having enhanced properties, performance and life. Accordingly, the disclosure also provides for the tyre so manufactured that exhibits reduced rolling resistance, reduced abrasion loss, increased tensile modulus, reduced heat build-up, and reduced fatigue failure, when compared to a tyre that does not comprise the composition of the present disclosure.
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. More particularly, the present disclosure provides a tyre 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 graphene as a reinforcing filler. The disclosure also provides a corresponding process that allows incorporation of the said graphene along with one or more of the said rubbers for preparing the composition of the present disclosure.
However, before describing the process 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 comprising up to a maximum of 15 layers. The graphene employed herein is preferably of high surface area, typically ranging between 1500 to 3000 m2/g. Accordingly, graphene referred to herein, does not imply or intend to cover graphite of any nature.
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.
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 graphene as a reinforcing filler. The said composition is typically used for manufacturing a tyre and improves its properties such as rolling resistance, abrasion resistance and wet grip. While the conventionally known tyre compositions employ different compounds as reinforcing filler, with carbon black and silica being the most common; the present disclosure provides a tyre composition where either the traditional reinforcing filler is completely or partially replaced by graphene, or where the 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 graphene is employed as a reinforcing filler. The graphene so employed is of high surface area, typically ranging between 1500 to 3000 m2/g, and preferably of about 2000 m2/g.
In non-limiting embodiments, 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, along with graphene at a concentration ranging from about 0.01% to about 18%, as a reinforcing filler.
Thus, the present disclosure relates to a tyre composition comprising at least one rubber and graphene, wherein the graphene is at a concentration ranging from about 0.01% to about 3.5%.
In exemplary embodiments, the concentration of graphene in the composition of the present disclosure ranges from about 10% to about 18%, or from about 0.03% to about 0.15%, or from about 0.05% to about 0.1%. In preferred embodiments, the concentration of graphene in the final composition ranges from about 0.01% to about 3.5%.
While the concentration of graphene in rubber masterbatch (comprising graphene with one or more rubber) ranges from about 0.01% to about 18%, the final tyre formulations prepared using the said masterbatch has the final graphene concentration of not more than 3.5phr. Thus, the maximum concentration of graphene at 18% refers to the maximum graphene content in masterbatch which is added to the final tyre formulations to get the effective graphene content to less than 3.5phr. Thus, accordingly, the concentration of the graphene in the final composition also ranges between about 0.01% to about 3.5%.
The quantity of the graphene with respect to the final composition prepared in the present disclosure ranges from about 0.01phr to about 3.5phr. Further, the graphene employed in the present disclosure is a monolayer graphene or a multilayered graphene comprising a maximum of about 15 layers.
Accordingly, in an 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, along with graphene at a concentration ranging from about 0.01% to about 18%, as a reinforcing filler. As mentioned previously, this maximum concentration of graphene at 18% refers to the maximum graphene content in masterbatch which is added to the final tyre formulations to get the effective graphene content to less than 3.5phr. Thus, accordingly, the concentration of the graphene in the final composition ranges between about 0.01% to about 3.5%.
In another 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, along with graphene at a concentration ranging from about 0.03% to about 0.15%, as a reinforcing filler.
In yet another 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, along with graphene at a concentration ranging from about 0.05% to about 0.1%, as a reinforcing filler.
As mentioned above, the present disclosure either provides a composition comprising only graphene as reinforcing filler or a composition comprising graphene in addition to other reinforcing fillers. In such a case, in non-limiting embodiments, the concentration of graphene ranges from about 2% to about 10%, and that of other reinforcing fillers ranges from 25% to about 70%.
In the present disclosure, while the concentration of 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 80%.
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 80%, along with graphene at a concentration ranging from about 0.01% to about 18% in the masterbatch, as a reinforcing filler. Thus, the concentration of the graphene in the final composition ranges between about 0.01% to about 3.5%.
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 graphene as a reinforcing filler. Accordingly, apart from the rubber and the reinforcing filler, the tyre composition of the present disclosure comprises 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. In another exemplary embodiment, the tyre composition comprises about 41% elastomer, about 28% filler, about 14 to 15% steel, and about 16 to 17% fabric and other additives.
In an embodiment, the tyre composition herein comprises additional components selected from processing oil ranging between about 1 to about 15 parts, stearic acid ranging between about 1 to about 5 parts, antioxidant ranging between about 0.25 to about 5 parts, tackifier ranging between about 0.5 to about 1.5 parts, sulfur ranging between about 1 to about 2 parts, pre vulcanization inhibitor ranging between about 0.05 to about 0.15 parts, peptiser ranging between about 0.1 to about 0.5 parts, wax ranging between about 0.5 to about 2.5 parts, zinc oxide ranging between about 1 to about 6 parts and accelerator ranging between about 1 to about 5 parts, or any combination of components thereof.
In a related embodiment, the anti-oxidant is selected from a group comprising 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ) and N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) or any combination thereof; wherein the stearic acid in presence of the zinc oxide forms zinc stearate for acting as accelerator activator; wherein the hydrocarbon resin acts as tackifier; wherein the pre vulcanization inhibitor is N-(cyclohexylthio)-phthalimide (CTP); wherein the processing oil is residual aromatic extract (RAE); wherein the plasticizer is CCF resin; and wherein the accelerator is selected from a group comprising N-tert-butyl-2-benzothiazyl sulfenamide (TBBS) and Tetrabenzylthiuram disulfide (TBzTD) or any combination thereof.
Accordingly, in an exemplary embodiment, the tyre composition of the present disclosure comprises components selected from a group comprising 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ) as antioxidant, stearic acid in presence of zinc oxide which forms zinc stearate for acting as accelerator activator, hydrocarbon resin to act as tackifier, N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) as anti-oxidant and anti-ozonant for elastomers, N-(cyclohexylthio)-phthalimide (CTP) as pre vulcanization inhibitor (to prevent premature curing of elastomer), peptiser to reduce viscosity of natural rubber and help in processing, residual aromatic extract (RAE) as oil, CCF resin as plasticizer, wax, sulphur, and N-tert-butyl-2-benzothiazyl sulfenamide (TBBS) & Tetrabenzylthiuram disulfide (TBzTD) as accelerator, or any combination thereof.
The tyre composition herein, further comprises components selected from a group of chemicals, metal reinforcements, textile reinforcements and additives, or any combination thereof.
Accordingly, in an exemplary embodiment, the composition of the present disclosure comprises about 10phr of technically specific rubber (TSR20), about 20.6phr of Trinseo solution styrene butadiene rubber - SLR 6430 (SSBR SLR 6430), about 52.5 phr of Trinseo solution styrene butadiene rubber - SLR 4601 (SSBR SLR 4601), about 25phr of PBR masterbatch (having about 2.5phr graphene), about 5phr of RAE, about 42.50phr of carbon black (N339), about 2.50phr of stearic acid, about 0.75phr of TMQ, about 1phr of HC resin, about 3phr of ZnO, about 3phr of 6PPD, about 1.50phr of wax, about 1.10phr of sulphur, about 1.60phr of TBBS and about 0.35phr of TBzTD.
In another exemplary embodiment, the composition of the present disclosure comprises about 77.50phr of styrene butadiene rubber (SBR), about 25phr of polybutadiene rubber (PBR) masterbatch (having about 2.5phr graphene), about 12phr of RAE oil, about 42.50phr of N339 carbon black, about 2.5phr of stearic Acid, about 0.75phr of TMQ, about 1phr of resin, about 3phr of ZnO, about 2phr of 6PPD, about 1.50phr of wax, about 1.10phr of sulphur, about 1.60phr of TBBS and about 0.35phr of TBzTD.
In another exemplary embodiment, the composition of the present disclosure comprises about 77.50phr of natural rubber, about 34.50phr of N 220 carbon black, about 5phr of ZnO, about 4phr of RAE/TDAE, about 2.50phr of stearic acid, about 25phr of PBR masterbatch(comprising about 2.5phr graphene), about 2.50phr of Ozone Prt. Wax, about 2.50phr of DTPD/6PPD, about 1.05phr of TBBS, about 1.55phr of sulphur and about 0.10phr of CTP.
In another exemplary embodiment, the composition of the present disclosure comprises about 101.9phr of natural rubber masterbatch (having about 2phr graphene), about 0.2phr of peptiser, about 34phr of N134 (carbon black), about 5phr of ZnO, about 3phr of stearic acid, about 2phr of 6PPD, about 0.7phr of TMQ, about 1.4phr of sulfur and about 1.4phr of TBBS.
In another exemplary embodiment, the composition of the present disclosure comprises about 103.05phr of natural rubber masterbatch (having about 3.05phr of graphene), about 0.2phr of peptiser, about 36phr of N134+A5:C27, about 5phr of ZnO, about 3phr of stearic acid, about 2phr of 6PPD, about 0.7phr of TMQ, about 1.4phr of sulfur and about 1.4phr of TBBS.
In another exemplary embodiment, the composition of the present disclosure comprises about 87.18phr of natural rubber masterbatch and about 15.44phr of PBR masterbatch (cumulatively having about 2.62phr of graphene), about 38phr of N134, about 6phr of oil, about 5phr of ZnO, about 3phr of stearic acid, about 2phr of 6PPD, about 0.7phr of TMQ, about 1.4phr of sulfur and about 1.4phr of TBBS.
In another exemplary embodiment, the composition of the present disclosure comprises about 70phr of SBR, about 7.50phr PBR, about 25phr of PBR masterbatch (having about 2.5phr of graphene), about 3phr of ZnO, about 1phr of stearic acid, about 1phr of TBBS and about 1.75phr of Sol S.
As mentioned previously, the inclusion of 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, and heat build-up. The properties are enhanced or improved in tyre compositions where traditional reinforcing fillers, such as carbon black, are replaced completely or partially by graphene, or where graphene is included in addition to said traditional reinforcing fillers.
In a non-limiting embodiment, the tyre composition of the present disclosure comprising graphene as the reinforcing filler reduces the rolling resistance (measured by Tand @ 60°C or 70°C) of a tyre by about 3% to about 30%.
In another non-limiting embodiment, the tyre composition of the present disclosure comprising graphene as the reinforcing filler reduces the abrasion loss (or increases the abrasion resistance) of a tyre by about 5% to about 40%.
In another non-limiting embodiment, the tyre composition of the present disclosure comprising graphene as the reinforcing filler reduces the weight of tread by 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. As is clear from the examples in the present disclosure, the compositions containing graphene have less amount of material. The less weight corresponds to the carbon black replaced by the graphene. Typically, the density of carbon black is 1.85g/cc compared to 0.02gm/cc of graphene. Thus, it is evident that replacing carbon black with low density graphene will have a positive effect on the weight reduction.
In another non-limiting embodiment, the tyre composition of the present disclosure comprising graphene as the reinforcing filler increases the tensile modulus (measured by modulation @ 200% or 300% elongation) of a tyre by about 10% to about 40%.
In another non-limiting embodiment, the tyre composition of the present disclosure comprising graphene as the reinforcing filler reduces the fatigue failure [measured by fatigue to failure test (FTFT)] of a tyre by about 40%.
In another non-limiting embodiment, the tyre composition of the present disclosure comprising graphene as the reinforcing filler reduces the heat build-up of a tyre (measured by Tand @ 100°C) by about 2% to about 25%.
In another non-limiting embodiment, the tyre composition of the present disclosure comprising graphene as the reinforcing filler improves the cut and chip resistance (measured by weight loss after 10 minutes from the sample wheel which is rotated at rpm 750±5 and is impacted by a tungsten carbide knife with a precision ground cutting edge rotated at 60 rpm.) by about 25%. An eccentric cam applies the knife at a specified frequency for a specified time, both of which can be set according to the application requirements.
As part of the present disclosure, in a tyre composition of typical natural rubber and SBR used widely in industries, when 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 about 1 part of graphene in a tyre composition, the rolling resistance of the tyre is reduced by about 3% to about 30%, 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 about 1 part of graphene in a tyre composition, the abrasion loss of the tyre is reduced (or the abrasion resistance is increased) by 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 graphene in a tyre composition, the weight of the tyre is reduced by 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 about 1 part of graphene in a tyre composition, the tensile modulus of the tyre is increased by 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 graphene in a tyre composition, the fatigue failure of the tyre is reduced by 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 graphene in a tyre composition, the heat build-up of the tyre is reduced by about 2% to about 25%, when compared to an identical composition containing only carbon black as the filler.
In yet another exemplary embodiment, when carbon black is replaced with graphene in a tyre composition, the wet grip of the tyre (measured by Tand, 0°C) is increased by about 10%, when compared to an identical composition containing only carbon black as the filler.
As mentioned previously, while the present disclosure provides the composition herein comprising graphene as a reinforcing filler that substantially enhances the properties of the tyre that it constitutes, it also provides a corresponding process that allows incorporation of the said graphene along with one or more of the said rubbers for preparing the composition of the present disclosure.
This is 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 the process herein.
The present disclosure thus relates to solution-based master batch process for production of the composition of the present disclosure. By this method, about 1% to about 18% of 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 process comprises steps including but not limited to mixing of the graphene with a combination of solvents, such as heptane, toluene and/or water, followed by adding the mixture to a combination of one or more rubbers or elastomers employed for preparing a tyre composition. Once mixed, a different type of solvent, such as isopropyl alcohol, is used to coagulate the rubber(s) or elastomer(s) from the mixture, to obtain a graphene-rubber/elastomer master batch, which is then used for manufacturing of tyres.
Accordingly, the process for preparing the tyre composition of the present disclosure comprises steps of:
a. mixing graphene with at least one rubber in presence of at least one solvent in a high shear mixer at rpm ranging between 2500 and 4000, for a time duration ranging from about 20 minutes to about 60 minutes to obtain a rubber masterbatch; and
b. mixing the rubber masterbatch with same or different rubber, optionally along with additional component to obtain the tyre composition of the present disclosure.
In embodiments of the present disclosure, the solvent is selected from a group comprising heptane, toluene and water, or any combination thereof. Further, as mentioned previously concentration of the graphene in the masterbatch ranges from about 0.01% to about 18%, whereas in the final composition ranges from 0.01% to about 3.5%.
In an exemplary embodiment, for preparing a composition comprising PBR, a mixture of toluene:n-heptane is emplpyed at the ratio of about 55:45, whereas for preparing a composition comprising SBR and NR, water is used.
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 10 parts of graphene can be mixed when used in combination with mineral oil. On the other hand, the process of the present disclosure allows mixing of up to about 10 parts of graphene in a tyre composition without any processing aid, including an oil.
The process of the present disclosure comprises steps including but not limited to mixing of graphene as a master batch in an internal 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 mixing of the graphene with a combination of solvents takes place 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 added to the combination of one or more rubbers or elastomers employed for preparing a tyre composition.
Since the most commonly used rubber is styrene-butadiene copolymer, the process of the present disclosure involves mixing of the graphene-elastomer masterbatch (referred to herein interchangeably as graphene masterbatch or rubber masterbatch) directly with the copolymer 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 after a combination of such rubbers is prepared. For example, if the rubbers employed are styrene-butadiene rubber (SBR) and polybutadiene rubber (PBR), the graphene is first mixed with PBR to form a masterbatch. Once the graphene and the PBR is mixed, other ingredients/components and SBR are added in the final formulation during the melt processing stage. If however one rubber elastomer is employed, the graphene is mixed with a portion of the said elastomer to prepare masterbatch, post which, the masterbatch is mixed with the remainder of the elastomer to prepare the final composition.
The mixing employed in the process of the present disclosure 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 to about 120.
In a non-limiting embodiment, the mixing employed in the process of the present disclosure is carried out at about 60°C at 60 rpm.
Accordingly, the process of the present disclosure allows incorporation of the graphene to prepare the composition of the present disclosure, which improves the properties of the tyre manufactured therefrom.
Thus, the present disclosure also relates to a method of improving at least one property of a tyre selected from a group comprising rolling resistance, abrasion loss, tensile modulus, heat build-up and fatigue failure, or any combination thereof, said method comprising act of manufacturing the tyre by employing the tyre composition of the present disclosure.
The composition accordingly reduces the rolling resistance of the tyre by about 3% to about 30%, reduces the abrasion loss of the tyre by about 5% to about 40%, increases the tensile modulus of the tyre by about 10% to about 40%, reduces the heat build-up of the tyre by about 2% to about 25%, and reduces the fatigue failure of the tyre by about 40%, when compared to a tyre that does not comprise the said composition.
The present disclosure accordingly also further relates to use of the composition herein comprising graphene as a reinforcing filler for manufacturing of tyres.
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 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 30%, 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 25%.
Thus, in total, the present disclosure provides a tyre composition comprising 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 graphene in the composition, such that a larger amount of graphene can be incorporated without use of or substantial help from external processing aids, such as oils. 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 composition comprising conventionally employed filler, such as carbon black. Such a composition 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 60°C at 60 rpm. For the purposes of the experiments below, the said composition is referred to as the conventional composition comprising carbon black as the reinforcing filler.
Further, within the present disclosure, properties as measured are abbreviated as follows:
ML- Minimum torque
MH- Maximum torque
Ts1, Ts2- Scorch time
Tc10, Tc25, Tc40, Tc50, Tc90- Cure time for 10%, 25%, 40%, 50% and 90% curing
Mod@100% elongation- Modulus at 100% elongation.
FTFT- Fatigue to failure test.
DMA- Dynamic mechanical analysis.
Tan d- Tangent delta.
Example 1
Preparation of the tyre composition of the present disclosure
Graphene master batch was prepared with about 1% to about 18% graphene. Briefly, the graphene was mixed with a combination of solvents along with one of the elastomers in a high-shear mixer at rpm ranging between 2500 and 4000, for a time duration ranging from about 20 minutes to about 60 minutes to obtain a graphene master batch.
Separately, a combination of styrene-butadiene rubber (SBR) and polybutadiene rubber (PBR) was prepared.
The graphene master batch was mixed with the combination of SBR and PBR (and other ingredients/components) in an internal mixer at 60°C and at 60 rpm for about 1 hour by melt mixing route to obtain the composition of the present disclosure.
Similarly, other exemplary mixtures were prepared with graphene, by varying the combination of rubbers involved to obtain the composition of the present disclosure. These include combinations of natural rubbers; natural rubber & PBR; natural rubber, PBR & SBR; and SBR & PBR.
Tyre tread formulations so prepared using the above compositions were tested for different properties as provided in the examples that follow.
Example 2
Preparation of the tyre composition of the present disclosure comprising graphene and PBR
Graphene master batch was prepared with about 30 gms of graphene mixed with about 6500 ml combination of toluene and N-heptane. The solution was mixed in high-shear mixer for a time duration of about 60 minutes at about 4000 RPM in L5M-A type or at about 2500 RPM in AX5 type silverson to obtain a graphene master batch (mixture 1).
Separately, a slurry of PBR was prepared in the same solvents. About 5000 gms of this PBR slurry was added into the graphene master batch and mixed in high-shear mixer with speed of 4000 RPM in L5M-A type or of about 2500 RPM in AX5 type silverson for about 1 hour to obtain mixture 2.
After an hour the mixing was stopped and about 10500 ml of isopropyl alcohol (IPA) was slowly added to the mixture 2 until black PBR elastomer separated 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 is used for two roll mill process.
The elastomer was then added into the rolling mill nip and band, as a continuous sheet, onto the front roll. The roll nip opening was set at 2.5 mm and temperature at 110° ± 5°C. Using a hand knife, 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 is formed on the nip. Solvent evaporation occurred during two roll milling process so the area was properly ventilated and scrubber was used for proper disposal of solvent vapours.
For addition of other ingredients, first, the batch weight of the rubber-graphene elastomer was calculated according to the fill factor. The graphene containing elastomer(s) and other raw materials were weighed as per the recipe and charged into a mixing chamber that is set at 100°C (when the elastomer used is NR) 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.
For rubber-graphene elastomer where natural rubber is employed, the peptiser was added in the first step and mixed for 30 seconds. The ram was raised and the chemicals were added (except sulphur and accelerator) into the chamber, followed by carbon black, post which the ram was lowered. The mixture was processed for a total of about 300 seconds. Maximum allowable temperature limit is 150°C. Next, processing oil was injected and mixed further for 60 seconds. The batch was allowed to cool for a minimum of 4hrs in air before proceeding with second-stage mix.
In the second stage, the initial temperature was kept at 70°C in TCU for 45 rpm. The material obtained at the previous step was cut into thin strips of about 1-2inch width and 5-6inch 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 180 seconds. Maximum allowable temperature limit is 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 4hrs before proceeding for testing.
Example 3
Testing of the composition of the present disclosure for rolling resistance
In a conventional composition comprising carbon black as the reinforcing filler, 5 parts of carbon black was replaced with 1 part of graphene (prepared as per protocol of example 1). Respective tyre was manufactured using the said composition (table 2 below) and tested for rolling resistance. As can be seen from table 2, the control sample had 55phr of carbon black whereas in the experimental formulation the carbon black amount is reduced to 42.5phr. In other words, 5 parts of carbon black is replaced by one part of graphene.
Data generated as per ASTM D5279 standard (table 1 below) by tangent delta plots at 70°C obtained by dynamic mechanical analysis show a minimum of 7% less rolling resistance when compared with the conventional composition comprising carbon black.
Properties Formulation with only carbon black Formulation with graphene and carbon black
Rheo Study (MDR 2000) @160°C / 30 min
ML(dN-M) 1.55 2.19
MH(dN-M) 13.98 16.28
Ts1 (Min) 3.37 2.44
Ts2 (Min) 3.72 2.79
TC10 (Min) 3.48 2.62
TC25 (Min) 3.93 3.04
TC40 (Min) 4.21 3.32
TC50 (Min) 4.42 3.54
TC90 (Min) 6.85 6.23
Final Tq.(dN-M) 13.75 15.79
Percentage Reversion 1.85 3.48
Cure Rate Index (CRI)(min¯¹) 3.97 4.10
Delta Tq.(dN-M) 12.43 14.09

Physicals - Unaged (Cured @160°C / Tc90+2 Min)

Mod @100% Elong.(MPa) 2.4 3.9
Mod @200% Elong.(MPa) 6.1 8.4
Mod @300% Elong.(MPa) 11.5 13.3
Tensile Strength (MPa) 22.8 21
% Elong @ Brk. 503 469
Hardness (Shore A) 59 63
Specific gravity

Physicals -Aged (@ 100 C/ 72 hrs) (Cured @160°C / Tc90+2 Min)
Mod @100% Elong.(MPa) 3.6 5.6
Mod @200% Elong.(MPa) 9.4 11.3
Mod @300% Elong.(MPa) 15.8 17
Tensile Strength (MPa) 19.6 18.5
% Elong @ Brk. 365 328
Hardness (Shore A) 67 70

FTFT (moulded@160°C, Tc90+2 min)
Failure(KC) 74.3 98.1

Abrasion Loss
Abrasion loss(in grams) 0.1162 0.1083
Abrasion loss(in mm cube) 104.97 99.45
Abrasion Resistance Index (%) 142.19 150.08
Specific gravity(g/cc) 1.107 1.089

DMA Temp Sweep @ 10 Hz, 2% static & 1% Dynamic Strain
Tan d @ 30°C 0.236 0.210
Tan d @ 70°C 0.171 0.158
Tan d @ 100°C 0.138 0.130
Table 1
Example 4
Testing of the composition of the present disclosure for abrasion resistance
In a conventional composition comprising carbon black as the reinforcing filler, 5 parts of carbon black was replaced with 1 part of graphene (prepared as per protocol of example 1). Respective tyre was manufactured using the said composition (table 2 below) and tested for abrasion loss/resistance. Data generated (table 1 above) as per ASTM D5963-04(2015) standard show a minimum of 5% reduction in abrasion loss when compared with the conventional composition comprising carbon black.
Example 5
Testing of the composition of the present disclosure for fatigue failure, tensile modulus and heat build-up
A composition was prepared as per the protocol of example 1 with 2.5 parts of graphene. A 10% (11.11phr) PBR-graphene master batch was prepared. Accordingly, in the formulation 25 phr masterbatch contains 2.5 phr graphene and 22.5 phr PBR. Thus, 2.5phr graphene corresponds to 1.47% graphene in the final composition. Respective tyre was manufactured using the said composition and tested for fatigue failure. Data generated as per ASTM D4482-11(2017) standard show a minimum of 30% reduction in fatigue failure when compared with the conventional composition comprising same amount of carbon black. Further, the composition also exhibited about 20% increase in tensile modulus [measured @200% Elong.(MPa)] as well as about 5.8% decrease in heat build-up.
Ingredients (phr) Control Experiment containing 2.5phr graphene % Values for the experimental compound
TSR 20 10.00 10.00 5.8685446
PBR 15.00 0.00 0
Trinseo SSBR SLR 6430 20.6 20.6 12.0892019
Trinseo SSBR SLR 4601 60 52.5 30.8098592
PBRM 0.00 25.00 14.6713615
RAE 5.00 5.00 2.9342723
N339 55.00 42.50 24.9413146
ST Acid 2.50 2.50 1.46713615
TMQ 0.75 0.75 0.44014085
HC Resin 1.00 1.00 0.58685446
ZnO 3.00 3.00 1.76056338
6PPD 3.00 3.00 1.76056338
WAX 1.50 1.50 0.88028169
Total Master 177.35 167.35 98.2100939

Master 177.35 167.35 98.2100939
Sulphur 1.10 1.10 0.64553991
TBBS 1.60 1.60 0.93896714
TBzTD 0.35 0.35 0.20539906
Total Final 180.40 170.40

Physicals - Unaged (Cured @160°C / Tc90+2 Min)
Mod @100% Elong.(MPa) 2.4 3.9
Mod @200% Elong.(MPa) 6.1 8.4
Mod @300% Elong.(MPa) 11.5 13.3
Tensile Strength (MPa) 22.8 21
% Elong @ Brk. 503 469
Hardness (Shore A) 59 63

DMA Temp Sweep @ 10 Hz, 2% static & 1% Dynamic Strain
Tan d @ 30°C 0.236 0.210
Tan d @ 70°C 0.171 0.158
Tan d @ 100°C 0.138 0.130

FTFT (moulded@160°C, Tc90+2 min)
Failure(KC) 74.3 98.1
Table 2
Example 6
Testing of the composition of the present disclosure for heat build-up and rolling resistance
Compositions were prepared as per the protocol of example 1 with 2.5 parts of graphene. The rubbers used were SBR and PBR for one composition (table 3); and natural rubber and PBR for the other (table 4). Respective tyre was manufactured using the said composition and tested for rolling resistance and heat build-up. Data generated as per ASTM D623-07(2014) standards are provided below. A significant reduction in heat build-up shows longer life when compared with the conventional composition comprising same amount of carbon black.
Ingredients (phr)/Properties Control (No graphene) Experiment containing 2.5phr (parts per hundred) graphene
(1.4% graphene) % Values for the experimental compound
Styrene butadiene rubber 77.50 77.50 45.37470726
Polybutadiene rubber (PBR) 22.5 0 0
PBR rubber containing graphene 0.00 25.00 14.63700234
RAE (Residual aromatic extract) oil 12.00 12.00 7.025761124
N339 carbon black 55.00 42.50 24.88290398
Stearic Acid 2.50 2.50 1.463700234
TMQ (anti oxidant) 0.75 0.75 0.43911007
Resin 1.00 1.00 0.585480094
ZnO 3.00 3.00 1.756440281
6PPD (anti oxidant and anti ozonant) 2.00 2.00 1.170960187
CCF Resin (plasticizer) 0.00 0.00 0
WAX 1.50 1.50 0.878220141
Sulphur 1.10 1.10 0.644028103
TBBS (accelerator) 1.60 1.60 0.93676815
TBzTD (accelerator) 0.35 0.35 0.204918033
Total Final 180.80 170.80

DMA Temp Sweep @ 10 Hz, 2% static & 1% Dynamic Strain
Tan d @ 0°C 0.310 0.279
Tan d @ 25°C 0.292 0.257
Tan d @ 60°C 0.240 0.207
Tan d @ 100°C 0.181 0.157
Table 3
Inference: As is seen, the composition comprising graphene (table 3) shows an improvement in each of rolling resistance as well as heat build-up by about 13%.
Ingredients(phr)/ Properties Control (No graphene) Experiment containing 2.5phr graphene
(1.6% graphene) % Values for the experimental compound
RMA 4 (Natural Rubber) 100.00 77.50 49.61588
N 220 Black 25.00 24.50 15.68502
Zinc Oxide 5.00 5.00 3.201024
RAE/TDAE 4.00 4.00 2.560819
St. Acid 2.50 2.50 1.600512
Master-1:Total 136.50 113.50 72.66325
0
Master-1 136.50 113.50 72.66325
PBRM (PBR master Batch) 0.00 25.00 16.00512
N 220 Black 22.00 10.00 6.402049
Ozone Prt. Wax 2.50 2.50 1.600512
DTPD/6PPD 2.50 2.50 1.600512
Total Master-2 163.50 153.50 98.27145
0
Master-2 163.50 153.50 98.27145
TBBS 1.00 1.05 0.672215
Standard Suphur 1.50 1.55 0.992318
CTP 0.10 0.10 0.06402
Final Total 166.10 156.20

Physicals – Unaged (Cured @ 141oC / Tc90+2 mins)
Mod @100% Elong.(Mpa) 2.4 3.7
Mod @200% Elong.(Mpa) 5.9 8.3
Mod @300% Elong.(Mpa) 11.2 13.6
Tensile Strength (Mpa) 32.1 30.9
% Elong @ Brk. 725 656
Hardness (Shore A) 60 63
Specific gravity

Abrasion Loss
Abrasion loss(in grams) 0.137 0.0827
Abrasion loss(in mm cube) 124.21 77.65
Abrasion Resistance Index (%) 120.17 192.21
Specific gravity(g/cc) 1.103 1.065

DMA Temp Sweep @ 10 Hz, 2% static & 1% Dynamic Strain
Tan d @ 30°C 0.224 0.177
Tan d @ 70°C 0.199 0.14921466
Tan d @ 100°C 0.177 0.131221719
Table 4
Inference: As is seen, the composition comprising graphene (table 4) shows an improvement in each of rolling resistance as well as heat build-up by about 25%. Further, the abrasion loss is reduced by about 37%, and the tensile modulus is improved by about 40%.
Example 7
Testing of natural rubber compositions of the present disclosure for different properties
A composition comprising natural rubber was prepared as per the instant disclosure with 14 phr of carbon black replaced by 2 phr of graphene. Respective tyre was manufactured using the said composition and tested for various properties. Data generated as per ASTM D623-07(2014) standard is provided below:

Ingredients(phr)/ Properties Control Experiment containing 2phr graphene
(1.3% graphene) % Values for the experimental compound
NR 100 -- --
NR-Graphene -- 101.9 68.11497326
Peptiser 0.2 0.2 0.13368984
N134 48 34 22.72727273
ZnO 5 5 3.342245989
St. Acid 3 3 2.005347594
6PPD 2 2 1.336898396
TMQ 0.7 0.7 0.467914439
Sulfur 1.4 1.4 0.935828877
TBBS 1.4 1.4 0.935828877
Final 161.7 149.6

Stress-Strain properties - Unaged (Cured @ 141oC)
Mod @100% Elong.(MPa) 3 3.8
Mod @200% Elong.(MPa) 8.8 10.3
Mod @300% Elong.(MPa) 17.2 18.2
Tensile Strength (MPa) 29.7 32.3
% Elong @ Brk. 478 487
Hardness (Shore A) 67 65

Abrasion Loss
Specific gravity(g/cc) 1.108 1.076
Abrasion loss(in grams) 0.1134 0.1065
Abrasion loss(in mm cube) 102 99

DMA Temp Sweep Shear Mode @ 10 Hz, 1% Dynamic Str+B48:S48ain (-60 to 80)
tand, 0°C 0.329 0.334
tand, 30°C 0.231 0.182
tand, 70°C 0.179 0.125
Table 5
Inference: As is seen, the composition comprising graphene (table 5) shows an improvement in rolling resistance by about 30%. Further, the abrasion loss is reduced by about 6%, and the tensile modulus is improved by about 17%. The composition also shows a significant improvement in wet grip characteristics.
Another composition comprising natural rubber was prepared as per the instant disclosure with 12 phr of carbon black replaced by 3.05 phr of graphene. Respective tyre was manufactured using the said composition and tested for various properties. Data generated as per ASTM D623-07(2014) standard is provided below:
Ingredients(phr)/ Properties Control Experiment containing 3.05phr graphene
(1.9% graphene) % Values for the experimental compound
NR 100 -- --
NR-Graphene -- 103.05 67.46317512
Peptiser 0.2 0.2 0.130932897
N134+A5:C27 48 36 23.56792144
ZnO 5 5 3.273322422
St. Acid 3 3 1.963993453
6PPD 2 2 1.309328969
TMQ 0.7 0.7 0.458265139
Sulfur 1.4 1.4 0.916530278
TBBS 1.4 1.4 0.916530278
Final 161.7 152.75

Stress-Strain properties - Unaged (Cured @ 141oC)
Mod @100% Elong.(MPa) 3 4.8
Mod @200% Elong.(MPa) 8.8 12
Mod @300% Elong.(MPa) 17.2 19.7
Tensile Strength (MPa) 29.7 28.4
% Elong @ Brk. 478 420
Hardness (Shore A) 67 69

DMA Temp Sweep Shear Mode @ 10 Hz, 1% Dynamic Str+B48:S48ain (-60 to 80)
tand, 0°C 0.329 0.303
tand, 30°C 0.231 0.186
tand, 70°C 0.179 0.139
Table 6
Inference: As is seen, the composition comprising graphene (table 6) shows an improvement in rolling resistance by about 22%. Further, the tensile modulus is improved by about 36%.
Example 8
Testing of natural rubber and PBR based composition of the present disclosure for different properties
A composition comprising natural rubber and PBR was prepared as per the present disclosure with 12 phr of carbon black replaced by 2.62 phr graphene. Respective tyre was manufactured using the said composition and tested for various properties. Data generated as per ASTM D623-07(2014) standard is provided below:
Ingredients(phr)/ Properties Control Experiment containing 2.62phr graphene
(1.6% graphene) % Values for the experimental compound
NR 85 - -
NR-Graphene - 87.18 54.44667
PBR 15 - -
PBR-Graphene - 15.44 9.642768
N134 50 38 23.7322
Oil 6 6 3.74719
ZnO 5 5 3.122658
St. Acid 3 3 1.873595
6PPD 2 2 1.249063
TMQ 0.7 0.7 0.437172
Sulfur 1.4 1.4 0.874344
TBBS 1.4 1.4 0.874344
Final 169.5 160.12

Stress-Strain properties - Unaged (Cured @ 141oC)
Mod @100% Elong.(MPa) 2.8 4.3
Mod @200% Elong.(MPa) 7.6 10.7
Mod @300% Elong.(MPa) 14.1 17.5
Tensile Strength (MPa) 30.4 29.2
% Elong @ Brk. 506 486
Hardness (Shore A) 65 67

Abrasion Loss
Specific gravity(g/cc) 1.111 1.078
Abrasion loss(in grams) 0.1049 0.0860
Abrasion loss(in mm cube) 94 80

DMA Temp Sweep Shear Mode @ 10 Hz, 1% Dynamic Str+B48:S48ain (-60 to 80)
tand, 0°C 0.315 0.300
tand, 30°C 0.224 0.194
tand, 70°C 0.176 0.147
Table 7
Inference: As is seen, the composition comprising graphene (table 7) shows an improvement in rolling resistance by about 16%. Further, the abrasion loss is reduced by about 15%, and the tensile modulus is improved by about 40%.
Example 9
Testing of SBR and PBR based compositions of the present disclosure for variation in graphene content
Three different compositions comprising SBR and PBR were prepared as per the present disclosure with 3 phr graphene, 4 phr graphene and 5 phr graphene. Respective tyres were manufactured using the said composition and tested for various properties. Data generated as per ASTM D623-07(2014) standard is provided below:
Table 8
Inference: As is seen, when the concentration of graphene is increased greater than 3 phr, the resultant properties are inferior. Tangent delta at 70°C, which is a measure of rolling resistance, increases with graphene amount, whereas loss in abrasion remains almost unchanged with increasing graphene content.
Example 10
Complete replacement of carbon black with graphene in the composition of the present disclosure
Composition according to the present disclosure is prepared as per the specifics provided in table 9 below, wherein, 20phr of carbon black is completely replaced by 2.5phr of graphene. Respective tyre was manufactured using the said composition and tested for rolling resistance, tensile modulus and heat build-up.
Ingredients(phr)/Properties Control (No graphene) Experiment containing 2.5phr graphene
Raw SBR 1502 (HMD) 70.00 70.00
Raw PBR CISAMER 01 30.00 7.50
PBR MB 0.00 25.00
Carbon N330 20.00 0.00
ZnO 3.00 3.00
ST ACID 1.00 1.00
TBBS 1.00 1.00
Sol S 1.75 1.75
Total Phr 126.75 109.25

Rheo Study (MDR 2000) @160°C / 30'
ML(dN-M) 1.45 1.56
MH(dN-M) 14.34 15.1
Ts1 (Min) 4.61 4.29
Ts2 (Min) 5.8 5.93
TC10 (Min) 5.12 5.1
TC25 (Min) 6.4 6.76
TC40 (Min) 7.13 7.52
TC50 (Min) 7.64 8
TC90 (Min) 12.49 12.36
Final Tq.(dN-M) 14.25 13.54
Delta Tq.(dN-M) 12.89 14.94
Cure Rate 1.93 2.32

Physicals - Unaged (Cured @ 160°C / t90+2 min)
Mod @100% Elong.(MPa) 1.8 2.6
Mod @200% Elong.(MPa) 3.7 5.2
Mod @300% Elong.(MPa) 6.7 8
Tensile Strength (MPa) 11.4 8.8
% Elong @ Brk. 415 331
Hardness (Shore A) 53 55

DMA Temp Sweep[ (10Hz / 1% dynamic Strain/2 %static strain)
Tan d @ 30°C 0.105 0.090
Tan d @ 70°C 0.084 0.073
Tan d @ 100°C 0.067 0.058
Table 9
Inference: As is seen, the composition comprising graphene (table 9) shows an improvement in each of rolling resistance as well as heat build-up by about 13%. Further, the tensile modulus is improved by about 40%.
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 will so fully reveal 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.
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 tyre composition comprising at least one rubber and graphene, wherein the graphene is at a concentration ranging from about 0.01% to about 3.5%.
2. The tyre composition as claimed in claim 1, wherein the graphene is present alongside the rubber in form of a rubber masterbatch, and wherein concentration of the graphene with respect to the masterbatch ranges from about 0.01% to about 18%.
3. The tyre composition as claimed in claim 1, wherein quantity of the graphene with respect to the composition ranges from about 0.01phr to about 3.5phr.
4. The tyre composition as claimed in claim 1, wherein the rubber is 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 or any combination thereof, at a concentration ranging from about 10% to about 80%.
5. The tyre composition as claimed in claim 1, wherein the graphene acts as a reinforcing filler in the composition, and is either the only reinforcing filler or is present alongside another reinforcing filler carbon black.
6. The tyre composition as claimed in claim 1, wherein the graphene is a monolayer graphene or a multilayered graphene comprising a maximum of about 15 layers.
7. The tyre composition as claimed in claim 1, comprising additional components selected from processing oil ranging between about 1 to about 15 parts, stearic acid ranging between about 1 to about 5 parts, antioxidant ranging between about 0.25 to about 5 parts, tackifier ranging between about 0.5 to about 1.5 parts, sulfur ranging between about 1 to about 2 parts, pre vulcanization inhibitor ranging between about 0.05 to about 0.15 parts, peptiser ranging between about 0.1 to about 0.5 parts, wax ranging between about 0.5 to about 2.5 parts, zinc oxide ranging between about 1 to about 6 parts and accelerator ranging between about 1 to about 5 parts, or any combination of components thereof.
8. The tyre composition as claimed in claim 7, wherein the anti-oxidant is selected from a group comprising 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ) and N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) or any combination thereof; wherein the stearic acid in presence of the zinc oxide forms zinc stearate for acting as accelerator activator; wherein the hydrocarbon resin acts as tackifier; wherein the pre vulcanization inhibitor is N-(cyclohexylthio)-phthalimide (CTP); wherein the processing oil is residual aromatic extract (RAE); wherein the plasticizer is CCF resin; and wherein the accelerator is selected from a group comprising N-tert-butyl-2-benzothiazyl sulfenamide (TBBS) and Tetrabenzylthiuram disulfide (TBzTD) or any combination thereof.
9. The tyre composition as claimed in claim 1, further comprising components selected from chemicals, metal reinforcements, textile reinforcements and additives, or any combination thereof.
10. The tyre composition as claimed in claim 1, comprising about 41% elastomer, about 28% filler, about 14 to about 15% steel, and about 16 to about 17% fabric and additives.
11. The tyre composition as claimed in claim 1, wherein the composition reduces the rolling resistance of the tyre by about 3% to about 30%, when compared to a tyre that does not comprise graphene as reinforcing filler.
12. The tyre composition as claimed in claim 1, wherein the composition reduces the abrasion loss of the tyre by about 5% to about 40%, when compared to a tyre that does not comprise graphene as reinforcing filler.
13. The tyre composition as claimed in claim 1, wherein the composition increases the tensile modulus of the tyre by about 10% to about 40%, when compared to a tyre that does not comprise graphene as reinforcing filler.
14. The tyre composition as claimed in claim 1, wherein the composition reduces the heat build-up of the tyre by about 2% to about 25%, when compared to a tyre that does not comprise graphene as reinforcing filler.
15. The tyre composition as claimed in claim 1, wherein the composition reduces the fatigue failure of the tyre by about 40%, when compared to a tyre that does not comprise graphene as reinforcing filler.
16. A process for preparing the tyre composition of claim 1, said method comprising steps of:
a. mixing graphene with at least one rubber in presence of at least one solvent in a high shear mixer at rpm ranging between 2500 and 4000, for a time duration ranging from about 20 minutes to about 60 minutes to obtain a rubber masterbatch; and
b. mixing the rubber masterbatch with same or different rubber, optionally along with additional component to obtain the tyre composition of claim 1.
17. The method as claimed in claim 16, wherein the solvent is selected from a group comprising heptane, toluene and water, or any combination thereof.
18. The method as claimed in claim 16, wherein concentration of the graphene in the masterbatch ranges from about 0.01% to about 18%.
19. A method of improving at least one property of a tyre selected from a group comprising rolling resistance, abrasion loss, tensile modulus, heat build-up and fatigue failure, or any combination thereof, said method comprising act of manufacturing the tyre by employing the tyre composition of claim 1.
20. The method as claimed in claim 19, wherein the composition reduces the rolling resistance of the tyre by about 3% to about 30%, reduces the abrasion loss of the tyre by about 5% to about 40%, increases the tensile modulus of the tyre by about 10% to about 40%, reduces the heat build-up of the tyre by about 2% to about 25%, and reduces the fatigue failure of the tyre by about 40%, when compared to a tyre that does not comprise composition of claim 1.
21. Use of the tyre composition of claim 1, for manufacturing a tyre.
22. A tyre manufactured from the tyre composition as claimed in claim 1.
23. The use and the tyre as claimed in any of claim 21 or 22, wherein the tyre exhibits reduced rolling resistance, reduced abrasion loss, increased tensile modulus, reduced heat build-up, and reduced fatigue failure, when compared to a tyre that does not comprise composition of claim 1.

Dated this 25th day of February 2019
Signature:
Name: DURGESH MUKHARYA
IN/PA-1541
To: Of K&S Partners, Bangalore
The Controller of Patents Agent for the Applicant
The Patent Office, at Mumbai