DESC:TECHNICAL FIELD
The present disclosure relates to polymer technology. More particularly, the present disclosure relates to an improved tread rubber composition using Potash Feldspar as a filler and its method of preparation.
BACKGROUND OF PRESENT INVENTION
Generally, for a tire tread, rubbers having a high frictional force have been sought from the viewpoint of safety. On the other hand, a tire that has a small rolling resistance, that is, rubbers having a small hysteresis loss at the time of tire rolling have been sought from the viewpoint of the environment and health. Various
proposals have been made to formulate a hard foreign substance or a hollow particle into a rubber to thereby form a micro irregularity on the surface of a rubber layer to provide better traction, but practically satisfactory results have not been obtained yet. These caused other problems such as an increase in the hardness of the rubber and the loss of flexibility of the rubber whereby the resultant tire does not easily follow the contours of the road.
US9090753 discusses the use of tire inner linear rubber composition containing rubber component, an inorganic filler as POLYFIL DL having an aspect ratio of 2 to 200, and optionally carbon black and/or a metal salt of aliphatic acid, wherein the inorganic filler, the carbon black and the metal salt of aliphatic acid are blended such that they satisfy a specific relation formula, exhibits excellent workability whereas present invention discusses about the use of tire tread rubber composition containing feldspar as filler in NR:SBR:PBR based rubber composition to provide low rolling resistance.
US9328213 discusses the use of tire inner liner rubber composition containing
100 parts by mass of the rubber ingredient (A) therein, from 1 to 9 parts by mass of carbon black (B) and from 80 to 150 parts by mass of a layered or platy clay mineral (C) to provide excellent air permeation resistance and improved in flexure failure resistance and to a weight-saving pneumatic tire provided with the rubber composition as the inner liner therein whereas present invention discusses

about the use of tire tread rubber composition containing feldspar as filler in NR:SBR:PBR based rubber composition to provide low rolling resistance.
DE2457441 discusses the use of all-weather tyre which has around or elongated recesses which lie at an angle of 30 degrees with respect to the vehicle
axle and this malt is mixed with corundum, synthetic carborundum, quartz or orthoclase-feldspar to have strongly anti-skid, Excellent road-holding on steep roads. Braking distances are considerably reduced and can be suitable for use in all seasons whereas present invention discusses the use of rubber composition containing feldspar as filler in NR:SBR:PBR based rubber composition to
provide low rolling resistance.
WO2018110684 discusses the use of rubber composition of the tread containing diene elastomer especially conjugated dienes along with reinforcing filler carbon black and reinforcing inorganic filler such as silica (SiO2) and/or the aluminous type, preferably alumina (Al2O3) and plasticizing agent of the tire to
improve the grip performance of the tire on snow without deteriorating the grip performance on dry ground whereas present invention discusses about the use of tire tread rubber composition containing feldspar as filler in NR:SBR:PBR based rubber composition to provide low rolling resistance.
Reference made to an article entitled “Effect of feldspar filler on physical and
dynamic properties of SBR/CB based tire tread compounds: Effect of addition method of silane coupling agent” by Nese Kaynak; Sinan Sen, Journal of Elastomers and Plastics 53(01), 16.04.2021 discusses about the use of SBR based tire tread compounds using feldspar (FLD) as an alumina-silicate inorganic filler along with reinforcing carbon black (CB) and modified FLD using bis(triethoxysilylpropyl) disulfide (TESPD) provides lower rolling resistance F- FLD due to its stronger interaction with the SBR elastomer molecules through the silane agent-assisted crosslinks of the F-FLD whereas present invention discusses about the use of tire tread rubber composition containing feldspar as filler in NR:SBR based rubber composition to provide low rolling resistance.

IN6990/DELNP/2015 discusses about use of rubber composition of tyre innerliner compound containing partly of butyl rubber and Halobutyl rubber along with 60 to 80 phr of silicon based lamellar mineral filler and 8 to 30 phr of carbon black mixture comprising a first carbon black with a nitrogen-absorption-measured
surface area (N2SA) of 21 to 39 m2 /g, and a second carbon black with a nitrogen- absorption- measured surface area (N2SA) of 70 to 120 m2 /g whereas present invention discusses about the use of rubber composition containing feldspar as a filler in NR:SBR:PBR blend-based tread composition to provide low rolling resistance.
IN10257/DELNP/2014 discusses the use of rubber composition of tire bead area insert containing polyisoprene elastomer along with inorganic reinforcing filler whereas present invention discusses about the use of rubber composition containing feldspar as a filler in NR:BR or NR:SBR or NR:SBR: PBR blend based tread rubber composition to provide low rolling resistance.
IN9309/DELNP/2013 discusses a composite cord comprising rubber core and rubber sheath along with nanoparticles whereas present invention discusses about the use of rubber composition containing feldspar as a filler in NR:SBR: PBR blend based tread rubber composition to provide low rolling resistance.
IN2431/DELNP/2014 discusses a rubber composition containing one diene elastomer, carbon black as reinforcing filler and as plasticizing hydrocarbon resin whereas present invention discusses about the use of rubber composition containing feldspar as a filler in NR:SBR:BR blend-based tread rubber composition to provide low rolling resistance.
IN3514/DELNP/2014 discusses about a tyre tread comprising: a plurality of tread pattern elements having side surfaces and a contact surface intended to make contact with the road during the rotation of a tyre provided with tread. Atleast one of the cover layer comprises an assembly of woven or non-woven fibres whereas present invention discusses about the use of rubber composition containing feldspar

as a filler in NR:SBR: PBR blend based tread rubber composition to provide low rolling resistance
IN202041026770 discusses the use of elastomeric nanocomposite for tyre tread which imparts excellent wet grip and superior processing characteristics along with
fuller’s earth clay and carbon black as reinforcing filler whereas present invention discusses about the use of rubber composition containing feldspar as filler in NR:SBR:PBR blend based tread rubber composition to provide low rolling resistance.
IN202017053882 discusses about the use of porous, chemically interconnected,
carbon-nanofibre comprising carbon networks for reinforcing elastomers in tyre tread rubber composition containing 10-20 phr of SBR to provide lower rolling resistance, higher wet grip, better abrasion resistance, higher flexibility and lower stiffness whereas present invention discusses about the use of rubber composition containing feldspar as filler in NR:SBR:PBR blend based tread
rubber composition to provide low rolling resistance.
IN202127015760 discusses about the use of specific nitrile rubbers and at least one separating agent and vulcanizable mixtures and vulcanizates made from these pulverulent mixtures to improve wet skid resistance, dry grip and rolling resistance whereas present invention discusses about the use of rubber composition containing
feldspar as a filler in NR:SBR:PBR blend based tread rubber composition to provide low rolling resistance.
IN201717005777 discusses about the use of rubber composition containing styrene- butadiene rubber along with nanocarbon and carbon black as reinforcing fillers whereas present invention discusses about the use of rubber composition containing feldspar as a filler in NR:SBR:PBR blend based tread rubber composition to provide low rolling resistance.
Effect of feldspar filler on physical and dynamic properties of SBR/CB based tire tread compounds - the effects of using feldspar (FLD) as an alumina-silicate inorganic filler, with carbon black (CB) as a novel binary filler system, on the properties of SBR compounds were investigated for tire applications. The bis(triethoxysilylpropyl) disulfide (TESPD) was used for modification of FLD. The SBR hybrid composites were produced by replacing 10 phr of CB filler with neat FLD and functionalized FLD (F-FLD). The TESPD was added directly to the rubber mixture including neat FLD. The SBR composite which has only CB filler (50CB) was found to have the highest damping parameter (tan d) value at 60C. On the other hand, the composites loaded with the CB and the FLD fillers exhibited relatively lower ‘tan d’ at the same temperature showing lower rolling resistance meaning better fuel saving performance. The lowest rolling resistance was achieved for the 40CB-10F-FLD most probably due to its stronger interaction with the SBR elastomer molecules through the silane agent-assisted crosslinks of the F-FLD. As another dynamic property, the storage moduli at 20C were found to be lower for the SBR hybrid composites as compared to that of the 50CB composite, exhibiting enhanced winter traction performance of the composites having FLD filler together with CB. The composites containing only 10 phr of FLD and F-FLD, on the other hand, exhibited very low tensile strength values which are not acceptable for tire tread materials. The referred technical publication discusses the use of soda feldspar in SBR based tread compound whereas present invention discusses the use of Potash feldspar as a filler in SBR: PBR:NR based tyre tread formulation to provide lower rolling resistance.
Hence there is a need for a solution, for providing a rubber composition for tire tread with improved physical characteristics, such as processing property, rolling resistance and is cost effective.

OBJECTS OF THE INVENTION:
The principal object of the present invention is to provide a tread rubber composition using potash feldspar as a filler and its method of preparation.
Yet another object of the present invention is to provide a NR:SBR: PBR blend based tyre tread rubber composition.
Yet another object of the present invention is to provide feldspar as a filler, and it can be used as a partial replacement for reinforcing filler carbon black or for reinforcing filler silica.
Yet another object of the present rubber composition is to reduce carbon footprint.
Another object of the present invention is to provide an improved rubber composition which is cost effective.
Yet another object of the present invention is to provide an improved rubber composition which has lower rolling resistance and better processing properties.
Yet another object of the present invention is to provide improved winter traction.
Yet another object of the present invention is to provide optimum tensile strength and elongation at break(%).
Yet another object of the present invention is to provide high rubber elasticity.

SUMMARY OF THE PRESENT INVENTION
In one aspect of the present disclosure, a rubber composition for tire tread is provided. The rubber composition for tire tread includes Styrene Butadiene Rubber (SBR), Polybutadiene Rubber (PBR), Natural Rubber (NR), Carbon Black,
Precipitated Silica, Silane coupling agent, potash Feldspar as a filler, Mild Extracted Solvate Oil (MES oil), Homogenizing Agent, Hydrocarbon Resin, MC wax, N-(1,3- Dimethylbutyl)-N’-phenyl-p- phenylenediamine (6PPD), Zinc Oxide, Stearic Acid, Sulphur, Diphenylguanidine (DPG), and N-cyclohexylbenzothiazole-2- sulphenamide (CBS).
In second aspect of the present disclosure, a method preparing a tire tread rubber composition be disclosure. The method includes the following steps:
a. Step 1: Preparation of Master Batchincludes charging a Banbury mixer with rubbers and homogenizing agent, mixing for 2 to 35 seconds at a head temperature of 65 to 80°C and an unloaded rotor speed of 45 to 60 rpm, sequentially adding carbon black, potash feldspar, process oil, and MC Wax, allowing mixing for 100 to 230 seconds until reaching a temperature of 140 to 145°C. Performing silanization for 60 to 80 seconds at 20 to 30 rpm, then dumping the compound at a temperature range of 150°C to 165°C and sheeting out in a laboratory two-roll mill.
b. Step 2: By adding Step 1 master batch, 6PPD, and zinc oxide in a Lab Banbury Mixer, mixing for 60 to 180 seconds, and dumping therubber compound at a temperature range of 110°C to 135°C, followed by sheeting out in a laboratory two-roll mill.
c. Step 3: Adding the masterbatch rubber compound of step 2 to the lab Banbury mixer and mixing for 60 to 180 seconds, followed by dumping the rubber compound at a temperature range of 110°C to 135°C, and sheeting out in a laboratory two-roll mill;
d. Preparation of Final Batch by charging the Step III master batch rubber compound into the mixing chamber, allowing it to mix for 10 to 20 seconds and adding accelerators and Vulcanization agent Sulphur, mixing for 60 to 90 seconds, and dumping the rubber compound at a temperature range of up to 95°C to 120°C. Performing final batch sheeting out in a laboratory two-roll mill.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 represent the FTIR ATR spectrum of Potash felspar which exhibits major peak at 1000.74 cm-1 which corresponds to Si(Al)-O stretching vibration , 1133.62 cm-1 which corresponds to Si-O stretching vibration, 768.92 cm-1 & 725.98 cm-1 which corresponds to Si-Si(Al) & Si-Si stretching vibrations and 646.95 cm-1 corresponds to O-Si(Al)-O bending vibrations.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Various embodiments of the disclosure are discussed in detail below. A person skilled in the relevant art will recognize that other components and configurations
may be used without parting from the spirit and scope of the disclosure. Thus, the following description are illustrative and are not to be construed as limiting. Numerous specific details are described to provide a thorough understanding of the disclosure. However, in certain instances, known details are not described in order to avoid obscuring the description.
References to one or an embodiment in the present disclosure can be references to the same embodiment or any embodiment; and such references mean at least one of the embodiments.
Reference to "one embodiment", "an embodiment", “one aspect”, “some aspects”, “an aspect” means that a particular feature, structure, or characteristic described in
connection with the embodiment is included in at least one embodiment of the disclosure. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Moreover, various features are described which be exhibited by some
embodiments and not by others.

A recital of one or more synonyms does not exclude the use of other synonyms. The use of examples anywhere in this specification including examples of any terms discussed herein is illustrative only and is not intended to further limit the scope and meaning of the disclosure or of any example term. Likewise, the disclosure is
not limited to various embodiments given in this specification. Without intent to limit the scope of the disclosure, examples of instruments, apparatus, and their related results according to the embodiments of the present disclosure are given below. Note that titles or subtitles be used in the examples for convenience of a reader, which in no way should limit the scope of the disclosure. Unless otherwise
defined, technical and scientific terms used herein have the meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. In the case of conflict, the present document, including definitions, will control.
Additional features and advantages of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or can
be learned by practice of the herein disclosed principles. These and other features of the disclosure will become more fully apparent from the following description and appended objectives or can be learned by the practice of the principles set forth herein.
In order to overcome above listed prior art discussed in the background, the present
invention disclosure therefore provides an improved tread rubber composition using potash feldspar as a mineral filler and method of preparation.
In one aspect of the present disclosure, a rubber composition for tire tread is provided. The rubber composition for tire tread includes Styrene Butadiene Rubber (SBR), Polybutadiene Rubber (PBR), Natural Rubber (NR), Carbon Black, Precipitated Silica, Silane coupling agent, potash feldspar as a filler, Mild Extracted Solvate Oil (MES oil), Homogenizing Agent (Struktol 40 MS), Hydrocarbon Resin (Impera resin 1504), MC wax, N-(1,3- Dimethylbutyl)-N’-phenyl-p-phenylenediamine (6PPD), Zinc Oxide, Stearic Acid, Sulphur, Diphenylguanidine (DPG), and N-cyclohexylbenzothiazole-2- sulphenamide (CBS).

In some aspects of the present invention, the elastomer matrix consisting of Styrene Butadiene Rubber (SBR) ranging from 10 to 80.0 parts per hundred rubber (phr), Polybutadiene Rubber (PBR) ranging from 10 to 60.0 phr and Natural Rubber (NR) ranging from 10 to 80.0 phr and the said elastomer matrix SBR:PBR: NR polymer blend in the ratio of 4: 3 : 3 for the tire tread rubber composition.
In some aspects of the present invention disclosure, the feldspar is a filler has a SiO2 content greater than 50%.
In some aspects of the present invention disclosure, the Feldspar used is Potash Feldspar having SiO2 – 68.65%, Al2O3 -17.12% and K2O -10.5%.
In some aspects of the present invention, the Process oil is MES oil (Mild Extracted Solvate).
In some aspects of the present invention, the coupling agent is a bifunctional, sulfur containing organosilane.
In some aspects of the present invention, the elastomer matrix is 100 phr and it is consisting of SBR: PBR: NR elastomer/polymer blends.
In some aspects of the present disclosure the Styrene Butadiene Rubber (SBR) range from 0 to 80.0 phr of the rubber composition for tire tread. Styrene butadiene rubber can be from emulsion or solution polymerization.
In some aspects of the present disclosure the Polybutadiene Rubber (PBR) range from 0 to 60.0 phr of the rubber composition for tire tread. Polybutadiene rubber grade can be from any of the catalyst using cobalt, nickel or neodymium and its combination thereof. In some aspects of the present disclosure the Natural Rubber (NR) range from 0 to 80.0 phr of the rubber composition for tire tread. Natural rubber grades can be from Ribbed Smoke Sheets, Constant viscosity natural rubber grades, ISNR 20, TSR 20 and its combination thereof. In some aspects of the present disclosure the Carbon black range from 20.0 to 80.0 phr of the rubber composition for tire tread. Carbon black grades can be selected from N100, N200, N300 series and its combination thereof. In some aspects of the present disclosure the Precipitated Silica range from 20.0 to 90.0 phr of the rubber composition for tire tread. It can be from precipitated silica or any of the High dispersible silica grades.
In some aspects of the present disclosure the Silane coupling agent range from 2.0 to 13.0 phr of the rubber composition for tire tread. It can be from the grades Si 69 or Si 75. In some aspects of the present disclosure the potash feldspar range from 5.0 to 70.0 phr of the rubber composition for tire tread. It is Potash feldspar with the major elements consists of SiO2 – 68.65%, Al2O3 -17.12%, K2O -10.5% and further analysis done in FTIR ATR which exhibits major peak at 1000.74 cm-1 which corresponds to Si(Al)-O stretching vibration , 1133.62 cm-1 which corresponds to Si-O stretching vibration, 768.92 cm-1 & 725.98 cm-1 which corresponds to Si-Si(Al) & Si-Si stretching vibrations and 646.95 cm-1 corresponds to O-Si(Al)-O bending vibrations.
In some aspects of the present disclosure the Mild Extracted Solvate Oil (MES oil) range from 0 to 15.0 phr of the rubber composition for tire tread. Process oil can be from TDAE Oil or RAE or any of the naturally occurring oils obtained from renewable resources.
In some aspects of the present disclosure the Homogenizing Agent range from 1.0 to 2.0 phr of the rubber composition for tire tread.
In some aspects of the present disclosure the Hydrocarbon Resin range from 1.0 to 8.0 phr of the rubber composition for tire tread.
In some aspects of the present disclosure the MC wax range from 1.0 to 2.0 phr of the rubber composition for tire tread.
In some aspects of the present disclosure the N-(1,3-Dimethylbutyl)-N’-phenyl-p- phenylenediamine (6PPD) range from 1.0 to 2.0 phr of the rubber composition for tire tread. It can be from TMQ, DTPD or combinations thereof.
In some aspects of the present disclosure the zinc oxide range from 2.0 to 3.5 phr of the rubber composition for tire tread.
In some aspects of the present disclosure the stearic acid range from 1.0 to 3.5 phr of the rubber composition for tire tread.
In some aspects of the present disclosure the sulphur range from 1.0 to 2.0 phr of the rubber composition for tire tread. It can be from soluble or insoluble type.
In some aspects of the present disclosure the Diphenylguanidine (DPG) range from 0 to 2.0 phr of the rubber composition for tire tread.
In some aspects of the present disclosure the N-cyclohexylbenzothiazole-2-sulphenamide (CBS) range from 1.0 to 2.5 phr of the rubber composition for tire tread. It can be from any of the sulfenamide grades.
In another aspect of the present disclosure, a control rubber composition is provided. The control rubber composition for tire tread include Styrene Butadiene Rubber (SBR), Polybutadiene Rubber (PBR), Natural Rubber (NR), Carbon Black, Precipitated Silica, Silane coupling agent, Mild Extracted Solvate Oil (MES oil), Homogenizing Agent, Hydrocarbon Resin, MC wax, N-(1,3-Dimethylbutyl)-N’-phenyl-p-phenylenediamine (6PPD), Zinc Oxide, Stearic Acid, Sulphur, Diphenylguanidine (DPG), and N- cyclohexylbenzothiazole-2-sulphenamide (CBS).
Table 1: Rubber Composition in phr

Ingredients C1 F1 F2 F3 F4 F5
SBR 1502 1 40 40 40 40 40 40
PBR 2 30 30 30 30 30 30
NR 3 30 30 30 30 30 30
Carbon Black N110 4 40 35 30 25 40 40
Precipitated Silica 5 20 20 20 20 15 -
SI 75 6 2 2 2 2 0.5 -
Potash Feld Spar 7 - 5 10 15 5 20
MES OIL 8 4.0 4.0 4.0 4.0 4.0 4.0
Struktol 40 MS, Homogenising agent 9 1.0 1.0 1.0 1.0 1.0 1.0
Impera Resin 1504 10 4.0 4.0 4.0 4.0 4.0 4.0
MC WAX 11 1.0 1.0 1.0 1.0 1.0 1.0
6 PPD 12 1.3 1.3 1.3 1.3 1.3 1.3
Zinc oxide 13 2.2 2.2 2.2 2.2 2.2 2.2
Stearic acid 14 1.2 1.2 1.2 1.2 1.2 1.2
Sulphur 15 1.4 1.4 1.4 1.4 1.4 1.4
CBS 16 1.4 1.4 1.4 1.4 1.4 1.4

1. SBR 1502 – It is non-oil extended styrene butadiene rubber (emulsion polymerized) with 23.4% of bound styrene content and its Mooney Viscosity in the range of 45 MU to 55 MU from Reliance Industries Limited, India.
2. PBR 1220 – It is a polybutadiene rubber with 96% high cis content and its Mooney Viscosity ML (1+4) @ 100 Deg C is in the range of 40 MU to 50 MU.
3. NR, ISNR 20-Indian Standard Natural Rubber ISNR 20 with the Mooney Viscosity, ML (1+4) at 100°C is 76 MU.
4. Carbon Black, N110 -It is the reinforcing filler HAF, High Abrasion Furnace having the Iodine adsorption No. 140 to 155 mg/gm, tinting strength value between 118 to 128 % ITRB, nitrogen surface area value between 122 to 132 m2/gm and COAN value ranges between 92 to 102 cc/100 gm. It is from Continental Carbon India Ltd, India.
5. Precipitated Silica – It is having the specific surface area ranging from 165 to 180 m2/gm and it is from from Madhu Silica Pvt ltd, Gujarat.
6. Coupling agent - Si75 is a bifunctional, sulfur containing organosilane from Nanjing Shuguang Silane Chemical Co Ltd, China.
7. Potash Feldspar – It is having the major elements consisting of SiO2 – 68.65%, Al2O3 -17.12%, K2O -10.5% and further analysis done in FTIR ATR which exhibits major peak at 1000.74 cm-1 which corresponds to Si(Al)-O stretching vibration , 1133.62 cm-1 which corresponds to Si-O stretching vibration, 768.92 cm-1 & 725.98 cm-1 which corresponds to Si-Si(Al) & Si-Si stretching vibrations and 646.95 cm-1 corresponds to O-Si(Al)-O bending vibrations. It is obtained from Quarro Global LLP, India.
8. MES Oil - Mild Extracted Solvate or Low PCA oil is used to improve the processability of rubber compounds from IOCL Limited, India.
9. Struktol 40 MS – It is a homogenizing agent Rhein Chemie, USA.
10. Impera Resin P1504 – It is a hydrocarbon resin having a softening point 85 Deg C and its glass transition temperature is 40 Deg C. It is from Eastman Chemical, USA. It helps in improving the performance of tyre and also it improves the tackiness of rubber compound.
11. MC Wax - Microcrystalline wax from GPL, India. It is used in rubber compounds to provide ozone resistance.
12. 6PPD- (N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine) from Nocil Limited, India. It is added to the rubber composition to provide resistance to thermo oxidative ageing of elastomers.
13. Zinc oxide-It is used as an activator for the sulphur vulcanization of rubbers enhances the vulcanization efficiency and reduces the vulcanization time from Ambica Dhatu Private Limited, India.
14. Stearic acid from 3F Industries Ltd., India. It is used as a Process aid. Also, Zinc oxide and Stearic acid are added to form zinc soap, improves the solubility of zinc oxide in the compound, and with the accelerator to form a complex, this complex reacts with sulphur to produce a strong cure activating system.
15. Sulphur is the vulcanizing agent from The Standard Chemical Co. Pvt Ltd, India.
16. CBS- (N-cyclohexyl-2-benzothiazolesulfenamide) - It is a delayed action accelerator suitable for diene rubbers from Nocil Limited, India.

In one aspect of the invention method of preparation of rubber compound/rubber composition for tire tread is disclosed.
The said method comprising:

i. Step 1: Preparing a master batch by charging a Banbury mixer with rubbers and a homogenizing agent, mixing for 2 to 35 seconds at a head temperature of 65°C to 80°C and an unloaded rotor speed of 45 to 60 rpm, sequentially adding carbon black, potash feldspar, process oil, and MC wax, hydrocarbon resin and allowing mixing for 100 to 230 seconds until a temperature of 140°C to 145°C is reached; and silanization for 60 to 80 seconds at 20 to 30 rpm, following dumping the rubber compound at a temperature range of 150°C to 165°C to sheet out in a laboratory two-roll mill;
ii. Step 2: adding step 1 master batch rubber compound, 6PPD and zinc oxide into a Lab Banbury Mixer, mixing for 60 to 180 seconds, and dumping the rubber compound at a temperature range of 110°C to 135°C, followed by sheeting out in a laboratory two-roll mill;
iii. Step 3: adding the step 2 master batch rubber compound into a lab Banbury mixer mixing for 60 to 180 seconds, followed by dumping the rubber compound at a temperature range of 110°C to 135°C, and sheeting out in a laboratory two-roll mill;
iv. Preparation of final batch rubber compound: charging the master batch of step 3 into a mixing chamber, mixing for 10 to 20 seconds followed by adding accelerators and sulfur as a vulcanization agent and mixing for 60 to 90 seconds;
dumping the rubber compound of step at a temperature range of 95°C to 120°C, followed by sheeting out the final batch rubber compound in a laboratory two-roll mill.

In some aspects of the present invention disclosure, the potash feldspar added during the master batch preparation has a SiO2 content greater than 50%, providing improved abrasion resistance to the tire tread.

In some aspects of the present invention disclosure, potash feldspar filler is used as a partial replacement for a reinforcing filler silica provides improved winter traction and lower rolling resistance along with optimum tensile strength and elongation at break %, high rubber elasticity and better processability

In some aspects of the present invention disclosure, potash feldspar filler is used as a partial replacement for a reinforcing filler carbon black providing process safety, improved winter traction and lower rolling resistance along with optimum tensile strength and elongation at break %, high rubber elasticity and better processability

Results:
Characterization of Cured Rubber Vulcanizate and Uncured Rubber Compound:
The compound properties are listed in Table 2 below-
Measurements and Tests:
The purpose of these tests is to measure the improved properties of the compositions related to the invention against control composition. For this, five compositions F1, F2, F3, F4, & F5 are prepared based on SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by potash fed spar and thus potash feldspar uses as a partial replacement for carbon black (F1, F2, F3) and also used as a partial replacement for reinforcing filler silica (F4, F5) are compared against SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1) are prepared and evaluated.
The present invention provides a 100 parts by weight of rubber composition F1, F2, F3 SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler carbon black gave process safety, MV value lowered by 6.34 % to 11.88 % when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).
Further, the present invention provides a 100 parts by weight of rubber composition F4, F5, SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler silica gave process safety, MV value lowered by 1.19% to 33.47 % when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).

Also, the present invention provides a 100 parts by weight of rubber composition F1, F2, F3 SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feld spar filler is used as a partial replacement for a reinforcing filler carbon black gave process safety, i.e., t5 value from comparable to 12.82 % improvement (t5 value greater than 18 minutes is ideal value for better processability) when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).

Further, the present invention provides a 100 parts by weight of rubber composition F4, F5, SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler silica gave process safety, t5 value are comparable (t5 value greater than 18 minutes is ideal value for better processability) when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).
Also, the present invention provides a 100 parts by weight of rubber composition F1, F2, F3 SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feld spar filler is used as a partial replacement for a reinforcing filler carbon black gave hardness value ranges from 61 to 62 Shore A.
Further, the present invention provides a 100 parts by weight of rubber composition F4, F5, SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler silica gave hardness value ranges 59 to 60 Shore A.

Also, the present invention provides a 100 parts by weight of rubber composition F1, F2, F3 SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler carbon black gave tensile strength value ranging from 20.18 Mpa to 20.84 Mpa (tensile strength value greater than 15 Mpa is acceptable for general tread compounds) when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).
Further, the present invention disclosure provides a 100 parts by weight of rubber composition F4, F5, SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler silica gave tensile strength value 19.10 Mpa to 20.18 Mpa (tensile strength value greater than 15 Mpa is acceptable for general tread compounds) when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).

Also, the present invention provides a 100 parts by weight of rubber composition F1, F2, F3 SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler carbon black gave Elongation at break value ranging from 579.44% to 592.10% (Elongation at break value greater than 425% is acceptable for general tread compounds) when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).
Further, The present invention provides a 100 parts by weight of rubber composition F4, F5, SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler silica gave Elongation at break value ranging from 556.75 % to 571.74% (Elongation at break value greater than 425% is acceptable for general tread compounds) when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).

Also, the present invention provides a 100 parts by weight of rubber composition F1, F2, F3 SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler carbon black gave high rubber elasticity and it is improved upto 9.87 % when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).
Further, the present invention provides a 100 parts by weight of rubber composition F4, F5, SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for sa reinforcing filler silica gave high rubber elasticity and it is improved by 4.70% to 14.53 % when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).

Also, the present invention provides a 100 parts by weight of rubber composition F1, F2, F3 SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler carbon black provides improved winter traction by 6.57% to 38.03% and rolling resistance lowered by 5.13% to 12.82% when compared to SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).
Further, the present invention provides a 100 parts by weight of rubber composition F4, F5, SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler silica provides improved winter traction by 26.89% to 40.30% and rolling resistance lowered by 5.13% to 13.46% when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).
Hence, the present invention SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler carbon black provides improved winter traction and lower rolling resistance along with optimum tensile strength and elongation at break %, high rubber elasticity and better processability characteristics when compared to SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).
Also, the present invention SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler silica provides improved winter traction and lower rolling resistance along with optimum tensile strength and elongation at break %, high rubber elasticity and better processability characteristics when compared to SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).

Table 2: Characterization of uncured rubber compound and cured rubber vulcanizate
Properties
C1 F1 F2 F3 F4 F5
M1. Hardness, Shore A 62 62 61 61 60 59
M2. Tensile Properties of Rubber Vulcanizate
Tensile Strength, Mpa
(Ideal Value greater than 15 Mpa)
21.71 20.84 20.64 20.18 20.80 19.10
Elongation @ Break % (Ideal value greater than 425 %) 560.10 579.44 588.48 592.10 571.74 556.75
M3. High Rubber Elasticity of Rubber Vulcanizate
M4. Rebound Resilience, 23+/-2 Deg C, % 47.84 48.2 52.56 52.56 50.09 54.79
Rebound Resilience, Index - 100.75 109.87 109.87 104.70 114.53
M5. Dynamic properties of Rubber Vulcanizate
Winter traction, E’ -20 Deg C, Mpa (Lower the index value is better) 33.47 31.27 23.77 20.74 24.47 19.98
Winter traction, E’ – 20 Deg C (Index – Lower the index value is better) - 93.43 71.01 62.15 73.11 59.69
Tan delta @ 60 Deg C 0.156 0.148 0.139 0.136 0.148 0.135
Tan delta @ 60 Deg C (Index) – Lower the index value is better - 94.87 89.10 87.18 94.87 86.54
M6. Mooney Scorch @ 125 Deg C
MV, MU 50.50 47.30 44.50 46.10 49.90 33.60
MV, MU (Index) - 93.66 88.12 91.29 98.81 66.53
T5, min:min 38.22 37.48 41.63 43.12 38.30 37.75
T5, min:min (Index) - 98.06 108.92 112.82 100.2 98.77

In a second aspect of the present invention disclosure, a method preparing a tire tread rubber composition be disclosure. The method include the following steps:
Preparation of I Master Batch includes charging a Banbury mixer with rubbers and homogenizing agent, mixing for 2 to 35 seconds at a head temperature of 65 to 80°C and an unloaded rotor speed of 45 to 60 rpm, sequentially adding carbon black, silica, potash feldspar, process oil, hydrocarbon resin and MC Wax, allowing mixing for 100 to 230 seconds until reaching a temperature of 140 to 145°C. Performing silanization for 60 to 80 seconds at 20 to 30 rpm, then dumping the rubber compound at a temperature range of 150°C to 165°C and sheeting out in a laboratory two-roll mill.
II Master Batch: Adding I master batch, 6PPD, and zinc oxide in a Lab Banbury Mixer, mixing for 60 to 180 seconds, and dumping the rubber compound at a temperature range of 110°C to 135°C, followed by sheeting out in a laboratory
two-roll mill.
III Master Batch: Adding Step II master batch and further mixing for 60 to 180 seconds, then dumping the rubber compound at a temperature range of 110°C to 135°C and sheeting out in a laboratory two-roll mill.
d. Preparation of Final Batch by charging the III master batch rubber
compound into the mixing chamber, allowing it to mix for 10 to 20 seconds and adding accelerators and Vulcanization agent Sulphur, mixing for 60 to 90 seconds, and dumping the rubber compound at a temperature range of up to 95°C to 120°C. Performing final batch sheeting out in a laboratory two-roll mill.
Another aspect of the present invention disclosure, a method preparing a tire tread rubber composition is provided. The method involved the following steps:
Preparation of Master Batch (when there is no silica in the rubber composition) includes charging a Banbury mixer with rubbers and homogenizing agent, mixing for 2 to 35 seconds at a head temperature of 65 to 80°C and an unloaded rotor speed of 45 to 60 rpm, sequentially adding carbon black, potash feldspar, process oil, hydrocarbon resin, stearic acid, MC Wax, 6PPD, Zinc oxide allowing mixing for 100 to 230 seconds until reacting a temperature of 150 to 160°C, then dumping the rubber compound at a temperature range of 150°C to 165°C and sheeting out in a laboratory two-roll mill.
Step II Master Batch: Adding Step I master batch and further mixing for 60 to 180 seconds, then dumping the rubber compound at a temperature range of 110°C to 135°C and sheeting out in a laboratory two-roll mill.
Preparation of Final Batch by charging the Step II master batch rubber
compound into the mixing chamber, allowing it to mix for 10 to 20 seconds and adding accelerators and Vulcanization agent Sulphur, mixing for 60 to 90 seconds, and dumping the rubber compound at a temperature range of up to 95°C to 120°C. Performing final batch sheeting out in a laboratory two-roll mill.
M1. Shore A Hardness:
Shore A Hardness of the Rubber Vulcanizates are assessed in accordance with ASTM D 2240 in Shore A Durometer
M2. Tensile Properties of the Rubber Vulcanizates
Tensile properties of the rubber vulcanizates are measured in accordance with ASTM D 412 in Universal testing machine.
M3. Rubber Elasticity of the Rubber Vulcanizates
Rubber Elasticity of the rubber vulcanizates are measured in accordance with ASTM D 7121 in Rebound Resilience tester, Zwick Roell make.
M4. Dynamic properties of the rubber vulcanizate: The dynamic properties of the rubber vulcanizate are measured on a dynamic mechanical analyzer (DMA Metravib +1000) with a dynamic strain 0.3% and a static strain – 0.6% temperature sweep from - 40 to +80°C, frequency: 10Hz in tension mode as per ASTM D5992.
E’ at – 20 °C is commonly used as a predictor of tyre winter/snow traction. Lower the E’ value at -20°C, better the winter/snow traction.
Tan delta at 60°C is commonly used as a predictor of rolling resistance. Lower the tan delta value at 60°C, lower the rolling resistance.
M5. Better processability (Process Requirements) of a Rubber Compound:
Mooney Scorch Characteristics (pre vulcanization characteristics using large rotor) for processability:
The Mooney Scorch measurements are carried out with a Mooney Viscometer (MV 2000 Alpha technologies, USA) according to ASTM D1646. MV indicates the minimum viscosity, t5 indicates the time to scorch (MV+5) which indicates the processing properties (process safety).
,CLAIMS:TECHNICAL FIELD
The present disclosure relates to polymer technology. More particularly, the present disclosure relates to an improved tread rubber composition using Potash Feldspar as a filler and its method of preparation.
BACKGROUND OF PRESENT INVENTION
Generally, for a tire tread, rubbers having a high frictional force have been sought from the viewpoint of safety. On the other hand, a tire that has a small rolling resistance, that is, rubbers having a small hysteresis loss at the time of tire rolling have been sought from the viewpoint of the environment and health. Various
proposals have been made to formulate a hard foreign substance or a hollow particle into a rubber to thereby form a micro irregularity on the surface of a rubber layer to provide better traction, but practically satisfactory results have not been obtained yet. These caused other problems such as an increase in the hardness of the rubber and the loss of flexibility of the rubber whereby the resultant tire does not easily follow the contours of the road.
US9090753 discusses the use of tire inner linear rubber composition containing rubber component, an inorganic filler as POLYFIL DL having an aspect ratio of 2 to 200, and optionally carbon black and/or a metal salt of aliphatic acid, wherein the inorganic filler, the carbon black and the metal salt of aliphatic acid are blended such that they satisfy a specific relation formula, exhibits excellent workability whereas present invention discusses about the use of tire tread rubber composition containing feldspar as filler in NR:SBR:PBR based rubber composition to provide low rolling resistance.
US9328213 discusses the use of tire inner liner rubber composition containing
100 parts by mass of the rubber ingredient (A) therein, from 1 to 9 parts by mass of carbon black (B) and from 80 to 150 parts by mass of a layered or platy clay mineral (C) to provide excellent air permeation resistance and improved in flexure failure resistance and to a weight-saving pneumatic tire provided with the rubber composition as the inner liner therein whereas present invention discusses

about the use of tire tread rubber composition containing feldspar as filler in NR:SBR:PBR based rubber composition to provide low rolling resistance.
DE2457441 discusses the use of all-weather tyre which has around or elongated recesses which lie at an angle of 30 degrees with respect to the vehicle
axle and this malt is mixed with corundum, synthetic carborundum, quartz or orthoclase-feldspar to have strongly anti-skid, Excellent road-holding on steep roads. Braking distances are considerably reduced and can be suitable for use in all seasons whereas present invention discusses the use of rubber composition containing feldspar as filler in NR:SBR:PBR based rubber composition to
provide low rolling resistance.
WO2018110684 discusses the use of rubber composition of the tread containing diene elastomer especially conjugated dienes along with reinforcing filler carbon black and reinforcing inorganic filler such as silica (SiO2) and/or the aluminous type, preferably alumina (Al2O3) and plasticizing agent of the tire to
improve the grip performance of the tire on snow without deteriorating the grip performance on dry ground whereas present invention discusses about the use of tire tread rubber composition containing feldspar as filler in NR:SBR:PBR based rubber composition to provide low rolling resistance.
Reference made to an article entitled “Effect of feldspar filler on physical and
dynamic properties of SBR/CB based tire tread compounds: Effect of addition method of silane coupling agent” by Nese Kaynak; Sinan Sen, Journal of Elastomers and Plastics 53(01), 16.04.2021 discusses about the use of SBR based tire tread compounds using feldspar (FLD) as an alumina-silicate inorganic filler along with reinforcing carbon black (CB) and modified FLD using bis(triethoxysilylpropyl) disulfide (TESPD) provides lower rolling resistance F- FLD due to its stronger interaction with the SBR elastomer molecules through the silane agent-assisted crosslinks of the F-FLD whereas present invention discusses about the use of tire tread rubber composition containing feldspar as filler in NR:SBR based rubber composition to provide low rolling resistance.

IN6990/DELNP/2015 discusses about use of rubber composition of tyre innerliner compound containing partly of butyl rubber and Halobutyl rubber along with 60 to 80 phr of silicon based lamellar mineral filler and 8 to 30 phr of carbon black mixture comprising a first carbon black with a nitrogen-absorption-measured
surface area (N2SA) of 21 to 39 m2 /g, and a second carbon black with a nitrogen- absorption- measured surface area (N2SA) of 70 to 120 m2 /g whereas present invention discusses about the use of rubber composition containing feldspar as a filler in NR:SBR:PBR blend-based tread composition to provide low rolling resistance.
IN10257/DELNP/2014 discusses the use of rubber composition of tire bead area insert containing polyisoprene elastomer along with inorganic reinforcing filler whereas present invention discusses about the use of rubber composition containing feldspar as a filler in NR:BR or NR:SBR or NR:SBR: PBR blend based tread rubber composition to provide low rolling resistance.
IN9309/DELNP/2013 discusses a composite cord comprising rubber core and rubber sheath along with nanoparticles whereas present invention discusses about the use of rubber composition containing feldspar as a filler in NR:SBR: PBR blend based tread rubber composition to provide low rolling resistance.
IN2431/DELNP/2014 discusses a rubber composition containing one diene elastomer, carbon black as reinforcing filler and as plasticizing hydrocarbon resin whereas present invention discusses about the use of rubber composition containing feldspar as a filler in NR:SBR:BR blend-based tread rubber composition to provide low rolling resistance.
IN3514/DELNP/2014 discusses about a tyre tread comprising: a plurality of tread pattern elements having side surfaces and a contact surface intended to make contact with the road during the rotation of a tyre provided with tread. Atleast one of the cover layer comprises an assembly of woven or non-woven fibres whereas present invention discusses about the use of rubber composition containing feldspar

as a filler in NR:SBR: PBR blend based tread rubber composition to provide low rolling resistance
IN202041026770 discusses the use of elastomeric nanocomposite for tyre tread which imparts excellent wet grip and superior processing characteristics along with
fuller’s earth clay and carbon black as reinforcing filler whereas present invention discusses about the use of rubber composition containing feldspar as filler in NR:SBR:PBR blend based tread rubber composition to provide low rolling resistance.
IN202017053882 discusses about the use of porous, chemically interconnected,
carbon-nanofibre comprising carbon networks for reinforcing elastomers in tyre tread rubber composition containing 10-20 phr of SBR to provide lower rolling resistance, higher wet grip, better abrasion resistance, higher flexibility and lower stiffness whereas present invention discusses about the use of rubber composition containing feldspar as filler in NR:SBR:PBR blend based tread
rubber composition to provide low rolling resistance.
IN202127015760 discusses about the use of specific nitrile rubbers and at least one separating agent and vulcanizable mixtures and vulcanizates made from these pulverulent mixtures to improve wet skid resistance, dry grip and rolling resistance whereas present invention discusses about the use of rubber composition containing
feldspar as a filler in NR:SBR:PBR blend based tread rubber composition to provide low rolling resistance.
IN201717005777 discusses about the use of rubber composition containing styrene- butadiene rubber along with nanocarbon and carbon black as reinforcing fillers whereas present invention discusses about the use of rubber composition containing feldspar as a filler in NR:SBR:PBR blend based tread rubber composition to provide low rolling resistance.
Effect of feldspar filler on physical and dynamic properties of SBR/CB based tire tread compounds - the effects of using feldspar (FLD) as an alumina-silicate inorganic filler, with carbon black (CB) as a novel binary filler system, on the properties of SBR compounds were investigated for tire applications. The bis(triethoxysilylpropyl) disulfide (TESPD) was used for modification of FLD. The SBR hybrid composites were produced by replacing 10 phr of CB filler with neat FLD and functionalized FLD (F-FLD). The TESPD was added directly to the rubber mixture including neat FLD. The SBR composite which has only CB filler (50CB) was found to have the highest damping parameter (tan d) value at 60C. On the other hand, the composites loaded with the CB and the FLD fillers exhibited relatively lower ‘tan d’ at the same temperature showing lower rolling resistance meaning better fuel saving performance. The lowest rolling resistance was achieved for the 40CB-10F-FLD most probably due to its stronger interaction with the SBR elastomer molecules through the silane agent-assisted crosslinks of the F-FLD. As another dynamic property, the storage moduli at 20C were found to be lower for the SBR hybrid composites as compared to that of the 50CB composite, exhibiting enhanced winter traction performance of the composites having FLD filler together with CB. The composites containing only 10 phr of FLD and F-FLD, on the other hand, exhibited very low tensile strength values which are not acceptable for tire tread materials. The referred technical publication discusses the use of soda feldspar in SBR based tread compound whereas present invention discusses the use of Potash feldspar as a filler in SBR: PBR:NR based tyre tread formulation to provide lower rolling resistance.
Hence there is a need for a solution, for providing a rubber composition for tire tread with improved physical characteristics, such as processing property, rolling resistance and is cost effective.

OBJECTS OF THE INVENTION:
The principal object of the present invention is to provide a tread rubber composition using potash feldspar as a filler and its method of preparation.
Yet another object of the present invention is to provide a NR:SBR: PBR blend based tyre tread rubber composition.
Yet another object of the present invention is to provide feldspar as a filler, and it can be used as a partial replacement for reinforcing filler carbon black or for reinforcing filler silica.
Yet another object of the present rubber composition is to reduce carbon footprint.
Another object of the present invention is to provide an improved rubber composition which is cost effective.
Yet another object of the present invention is to provide an improved rubber composition which has lower rolling resistance and better processing properties.
Yet another object of the present invention is to provide improved winter traction.
Yet another object of the present invention is to provide optimum tensile strength and elongation at break(%).
Yet another object of the present invention is to provide high rubber elasticity.

SUMMARY OF THE PRESENT INVENTION
In one aspect of the present disclosure, a rubber composition for tire tread is provided. The rubber composition for tire tread includes Styrene Butadiene Rubber (SBR), Polybutadiene Rubber (PBR), Natural Rubber (NR), Carbon Black,
Precipitated Silica, Silane coupling agent, potash Feldspar as a filler, Mild Extracted Solvate Oil (MES oil), Homogenizing Agent, Hydrocarbon Resin, MC wax, N-(1,3- Dimethylbutyl)-N’-phenyl-p- phenylenediamine (6PPD), Zinc Oxide, Stearic Acid, Sulphur, Diphenylguanidine (DPG), and N-cyclohexylbenzothiazole-2- sulphenamide (CBS).
In second aspect of the present disclosure, a method preparing a tire tread rubber composition be disclosure. The method includes the following steps:
a. Step 1: Preparation of Master Batchincludes charging a Banbury mixer with rubbers and homogenizing agent, mixing for 2 to 35 seconds at a head temperature of 65 to 80°C and an unloaded rotor speed of 45 to 60 rpm, sequentially adding carbon black, potash feldspar, process oil, and MC Wax, allowing mixing for 100 to 230 seconds until reaching a temperature of 140 to 145°C. Performing silanization for 60 to 80 seconds at 20 to 30 rpm, then dumping the compound at a temperature range of 150°C to 165°C and sheeting out in a laboratory two-roll mill.
b. Step 2: By adding Step 1 master batch, 6PPD, and zinc oxide in a Lab Banbury Mixer, mixing for 60 to 180 seconds, and dumping therubber compound at a temperature range of 110°C to 135°C, followed by sheeting out in a laboratory two-roll mill.
c. Step 3: Adding the masterbatch rubber compound of step 2 to the lab Banbury mixer and mixing for 60 to 180 seconds, followed by dumping the rubber compound at a temperature range of 110°C to 135°C, and sheeting out in a laboratory two-roll mill;
d. Preparation of Final Batch by charging the Step III master batch rubber compound into the mixing chamber, allowing it to mix for 10 to 20 seconds and adding accelerators and Vulcanization agent Sulphur, mixing for 60 to 90 seconds, and dumping the rubber compound at a temperature range of up to 95°C to 120°C. Performing final batch sheeting out in a laboratory two-roll mill.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 represent the FTIR ATR spectrum of Potash felspar which exhibits major peak at 1000.74 cm-1 which corresponds to Si(Al)-O stretching vibration , 1133.62 cm-1 which corresponds to Si-O stretching vibration, 768.92 cm-1 & 725.98 cm-1 which corresponds to Si-Si(Al) & Si-Si stretching vibrations and 646.95 cm-1 corresponds to O-Si(Al)-O bending vibrations.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Various embodiments of the disclosure are discussed in detail below. A person skilled in the relevant art will recognize that other components and configurations
may be used without parting from the spirit and scope of the disclosure. Thus, the following description are illustrative and are not to be construed as limiting. Numerous specific details are described to provide a thorough understanding of the disclosure. However, in certain instances, known details are not described in order to avoid obscuring the description.
References to one or an embodiment in the present disclosure can be references to the same embodiment or any embodiment; and such references mean at least one of the embodiments.
Reference to "one embodiment", "an embodiment", “one aspect”, “some aspects”, “an aspect” means that a particular feature, structure, or characteristic described in
connection with the embodiment is included in at least one embodiment of the disclosure. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Moreover, various features are described which be exhibited by some
embodiments and not by others.

A recital of one or more synonyms does not exclude the use of other synonyms. The use of examples anywhere in this specification including examples of any terms discussed herein is illustrative only and is not intended to further limit the scope and meaning of the disclosure or of any example term. Likewise, the disclosure is
not limited to various embodiments given in this specification. Without intent to limit the scope of the disclosure, examples of instruments, apparatus, and their related results according to the embodiments of the present disclosure are given below. Note that titles or subtitles be used in the examples for convenience of a reader, which in no way should limit the scope of the disclosure. Unless otherwise
defined, technical and scientific terms used herein have the meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. In the case of conflict, the present document, including definitions, will control.
Additional features and advantages of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or can
be learned by practice of the herein disclosed principles. These and other features of the disclosure will become more fully apparent from the following description and appended objectives or can be learned by the practice of the principles set forth herein.
In order to overcome above listed prior art discussed in the background, the present
invention disclosure therefore provides an improved tread rubber composition using potash feldspar as a mineral filler and method of preparation.
In one aspect of the present disclosure, a rubber composition for tire tread is provided. The rubber composition for tire tread includes Styrene Butadiene Rubber (SBR), Polybutadiene Rubber (PBR), Natural Rubber (NR), Carbon Black, Precipitated Silica, Silane coupling agent, potash feldspar as a filler, Mild Extracted Solvate Oil (MES oil), Homogenizing Agent (Struktol 40 MS), Hydrocarbon Resin (Impera resin 1504), MC wax, N-(1,3- Dimethylbutyl)-N’-phenyl-p-phenylenediamine (6PPD), Zinc Oxide, Stearic Acid, Sulphur, Diphenylguanidine (DPG), and N-cyclohexylbenzothiazole-2- sulphenamide (CBS).

In some aspects of the present invention, the elastomer matrix consisting of Styrene Butadiene Rubber (SBR) ranging from 10 to 80.0 parts per hundred rubber (phr), Polybutadiene Rubber (PBR) ranging from 10 to 60.0 phr and Natural Rubber (NR) ranging from 10 to 80.0 phr and the said elastomer matrix SBR:PBR: NR polymer blend in the ratio of 4: 3 : 3 for the tire tread rubber composition.
In some aspects of the present invention disclosure, the feldspar is a filler has a SiO2 content greater than 50%.
In some aspects of the present invention disclosure, the Feldspar used is Potash Feldspar having SiO2 – 68.65%, Al2O3 -17.12% and K2O -10.5%.
In some aspects of the present invention, the Process oil is MES oil (Mild Extracted Solvate).
In some aspects of the present invention, the coupling agent is a bifunctional, sulfur containing organosilane.
In some aspects of the present invention, the elastomer matrix is 100 phr and it is consisting of SBR: PBR: NR elastomer/polymer blends.
In some aspects of the present disclosure the Styrene Butadiene Rubber (SBR) range from 0 to 80.0 phr of the rubber composition for tire tread. Styrene butadiene rubber can be from emulsion or solution polymerization.
In some aspects of the present disclosure the Polybutadiene Rubber (PBR) range from 0 to 60.0 phr of the rubber composition for tire tread. Polybutadiene rubber grade can be from any of the catalyst using cobalt, nickel or neodymium and its combination thereof. In some aspects of the present disclosure the Natural Rubber (NR) range from 0 to 80.0 phr of the rubber composition for tire tread. Natural rubber grades can be from Ribbed Smoke Sheets, Constant viscosity natural rubber grades, ISNR 20, TSR 20 and its combination thereof. In some aspects of the present disclosure the Carbon black range from 20.0 to 80.0 phr of the rubber composition for tire tread. Carbon black grades can be selected from N100, N200, N300 series and its combination thereof. In some aspects of the present disclosure the Precipitated Silica range from 20.0 to 90.0 phr of the rubber composition for tire tread. It can be from precipitated silica or any of the High dispersible silica grades.
In some aspects of the present disclosure the Silane coupling agent range from 2.0 to 13.0 phr of the rubber composition for tire tread. It can be from the grades Si 69 or Si 75. In some aspects of the present disclosure the potash feldspar range from 5.0 to 70.0 phr of the rubber composition for tire tread. It is Potash feldspar with the major elements consists of SiO2 – 68.65%, Al2O3 -17.12%, K2O -10.5% and further analysis done in FTIR ATR which exhibits major peak at 1000.74 cm-1 which corresponds to Si(Al)-O stretching vibration , 1133.62 cm-1 which corresponds to Si-O stretching vibration, 768.92 cm-1 & 725.98 cm-1 which corresponds to Si-Si(Al) & Si-Si stretching vibrations and 646.95 cm-1 corresponds to O-Si(Al)-O bending vibrations.
In some aspects of the present disclosure the Mild Extracted Solvate Oil (MES oil) range from 0 to 15.0 phr of the rubber composition for tire tread. Process oil can be from TDAE Oil or RAE or any of the naturally occurring oils obtained from renewable resources.
In some aspects of the present disclosure the Homogenizing Agent range from 1.0 to 2.0 phr of the rubber composition for tire tread.
In some aspects of the present disclosure the Hydrocarbon Resin range from 1.0 to 8.0 phr of the rubber composition for tire tread.
In some aspects of the present disclosure the MC wax range from 1.0 to 2.0 phr of the rubber composition for tire tread.
In some aspects of the present disclosure the N-(1,3-Dimethylbutyl)-N’-phenyl-p- phenylenediamine (6PPD) range from 1.0 to 2.0 phr of the rubber composition for tire tread. It can be from TMQ, DTPD or combinations thereof.
In some aspects of the present disclosure the zinc oxide range from 2.0 to 3.5 phr of the rubber composition for tire tread.
In some aspects of the present disclosure the stearic acid range from 1.0 to 3.5 phr of the rubber composition for tire tread.
In some aspects of the present disclosure the sulphur range from 1.0 to 2.0 phr of the rubber composition for tire tread. It can be from soluble or insoluble type.
In some aspects of the present disclosure the Diphenylguanidine (DPG) range from 0 to 2.0 phr of the rubber composition for tire tread.
In some aspects of the present disclosure the N-cyclohexylbenzothiazole-2-sulphenamide (CBS) range from 1.0 to 2.5 phr of the rubber composition for tire tread. It can be from any of the sulfenamide grades.
In another aspect of the present disclosure, a control rubber composition is provided. The control rubber composition for tire tread include Styrene Butadiene Rubber (SBR), Polybutadiene Rubber (PBR), Natural Rubber (NR), Carbon Black, Precipitated Silica, Silane coupling agent, Mild Extracted Solvate Oil (MES oil), Homogenizing Agent, Hydrocarbon Resin, MC wax, N-(1,3-Dimethylbutyl)-N’-phenyl-p-phenylenediamine (6PPD), Zinc Oxide, Stearic Acid, Sulphur, Diphenylguanidine (DPG), and N- cyclohexylbenzothiazole-2-sulphenamide (CBS).
Table 1: Rubber Composition in phr

Ingredients C1 F1 F2 F3 F4 F5
SBR 1502 1 40 40 40 40 40 40
PBR 2 30 30 30 30 30 30
NR 3 30 30 30 30 30 30
Carbon Black N110 4 40 35 30 25 40 40
Precipitated Silica 5 20 20 20 20 15 -
SI 75 6 2 2 2 2 0.5 -
Potash Feld Spar 7 - 5 10 15 5 20
MES OIL 8 4.0 4.0 4.0 4.0 4.0 4.0
Struktol 40 MS, Homogenising agent 9 1.0 1.0 1.0 1.0 1.0 1.0
Impera Resin 1504 10 4.0 4.0 4.0 4.0 4.0 4.0
MC WAX 11 1.0 1.0 1.0 1.0 1.0 1.0
6 PPD 12 1.3 1.3 1.3 1.3 1.3 1.3
Zinc oxide 13 2.2 2.2 2.2 2.2 2.2 2.2
Stearic acid 14 1.2 1.2 1.2 1.2 1.2 1.2
Sulphur 15 1.4 1.4 1.4 1.4 1.4 1.4
CBS 16 1.4 1.4 1.4 1.4 1.4 1.4

1. SBR 1502 – It is non-oil extended styrene butadiene rubber (emulsion polymerized) with 23.4% of bound styrene content and its Mooney Viscosity in the range of 45 MU to 55 MU from Reliance Industries Limited, India.
2. PBR 1220 – It is a polybutadiene rubber with 96% high cis content and its Mooney Viscosity ML (1+4) @ 100 Deg C is in the range of 40 MU to 50 MU.
3. NR, ISNR 20-Indian Standard Natural Rubber ISNR 20 with the Mooney Viscosity, ML (1+4) at 100°C is 76 MU.
4. Carbon Black, N110 -It is the reinforcing filler HAF, High Abrasion Furnace having the Iodine adsorption No. 140 to 155 mg/gm, tinting strength value between 118 to 128 % ITRB, nitrogen surface area value between 122 to 132 m2/gm and COAN value ranges between 92 to 102 cc/100 gm. It is from Continental Carbon India Ltd, India.
5. Precipitated Silica – It is having the specific surface area ranging from 165 to 180 m2/gm and it is from from Madhu Silica Pvt ltd, Gujarat.
6. Coupling agent - Si75 is a bifunctional, sulfur containing organosilane from Nanjing Shuguang Silane Chemical Co Ltd, China.
7. Potash Feldspar – It is having the major elements consisting of SiO2 – 68.65%, Al2O3 -17.12%, K2O -10.5% and further analysis done in FTIR ATR which exhibits major peak at 1000.74 cm-1 which corresponds to Si(Al)-O stretching vibration , 1133.62 cm-1 which corresponds to Si-O stretching vibration, 768.92 cm-1 & 725.98 cm-1 which corresponds to Si-Si(Al) & Si-Si stretching vibrations and 646.95 cm-1 corresponds to O-Si(Al)-O bending vibrations. It is obtained from Quarro Global LLP, India.
8. MES Oil - Mild Extracted Solvate or Low PCA oil is used to improve the processability of rubber compounds from IOCL Limited, India.
9. Struktol 40 MS – It is a homogenizing agent Rhein Chemie, USA.
10. Impera Resin P1504 – It is a hydrocarbon resin having a softening point 85 Deg C and its glass transition temperature is 40 Deg C. It is from Eastman Chemical, USA. It helps in improving the performance of tyre and also it improves the tackiness of rubber compound.
11. MC Wax - Microcrystalline wax from GPL, India. It is used in rubber compounds to provide ozone resistance.
12. 6PPD- (N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine) from Nocil Limited, India. It is added to the rubber composition to provide resistance to thermo oxidative ageing of elastomers.
13. Zinc oxide-It is used as an activator for the sulphur vulcanization of rubbers enhances the vulcanization efficiency and reduces the vulcanization time from Ambica Dhatu Private Limited, India.
14. Stearic acid from 3F Industries Ltd., India. It is used as a Process aid. Also, Zinc oxide and Stearic acid are added to form zinc soap, improves the solubility of zinc oxide in the compound, and with the accelerator to form a complex, this complex reacts with sulphur to produce a strong cure activating system.
15. Sulphur is the vulcanizing agent from The Standard Chemical Co. Pvt Ltd, India.
16. CBS- (N-cyclohexyl-2-benzothiazolesulfenamide) - It is a delayed action accelerator suitable for diene rubbers from Nocil Limited, India.

In one aspect of the invention method of preparation of rubber compound/rubber composition for tire tread is disclosed.
The said method comprising:

i. Step 1: Preparing a master batch by charging a Banbury mixer with rubbers and a homogenizing agent, mixing for 2 to 35 seconds at a head temperature of 65°C to 80°C and an unloaded rotor speed of 45 to 60 rpm, sequentially adding carbon black, potash feldspar, process oil, and MC wax, hydrocarbon resin and allowing mixing for 100 to 230 seconds until a temperature of 140°C to 145°C is reached; and silanization for 60 to 80 seconds at 20 to 30 rpm, following dumping the rubber compound at a temperature range of 150°C to 165°C to sheet out in a laboratory two-roll mill;
ii. Step 2: adding step 1 master batch rubber compound, 6PPD and zinc oxide into a Lab Banbury Mixer, mixing for 60 to 180 seconds, and dumping the rubber compound at a temperature range of 110°C to 135°C, followed by sheeting out in a laboratory two-roll mill;
iii. Step 3: adding the step 2 master batch rubber compound into a lab Banbury mixer mixing for 60 to 180 seconds, followed by dumping the rubber compound at a temperature range of 110°C to 135°C, and sheeting out in a laboratory two-roll mill;
iv. Preparation of final batch rubber compound: charging the master batch of step 3 into a mixing chamber, mixing for 10 to 20 seconds followed by adding accelerators and sulfur as a vulcanization agent and mixing for 60 to 90 seconds;
dumping the rubber compound of step at a temperature range of 95°C to 120°C, followed by sheeting out the final batch rubber compound in a laboratory two-roll mill.

In some aspects of the present invention disclosure, the potash feldspar added during the master batch preparation has a SiO2 content greater than 50%, providing improved abrasion resistance to the tire tread.

In some aspects of the present invention disclosure, potash feldspar filler is used as a partial replacement for a reinforcing filler silica provides improved winter traction and lower rolling resistance along with optimum tensile strength and elongation at break %, high rubber elasticity and better processability

In some aspects of the present invention disclosure, potash feldspar filler is used as a partial replacement for a reinforcing filler carbon black providing process safety, improved winter traction and lower rolling resistance along with optimum tensile strength and elongation at break %, high rubber elasticity and better processability

Results:
Characterization of Cured Rubber Vulcanizate and Uncured Rubber Compound:
The compound properties are listed in Table 2 below-
Measurements and Tests:
The purpose of these tests is to measure the improved properties of the compositions related to the invention against control composition. For this, five compositions F1, F2, F3, F4, & F5 are prepared based on SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by potash fed spar and thus potash feldspar uses as a partial replacement for carbon black (F1, F2, F3) and also used as a partial replacement for reinforcing filler silica (F4, F5) are compared against SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1) are prepared and evaluated.
The present invention provides a 100 parts by weight of rubber composition F1, F2, F3 SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler carbon black gave process safety, MV value lowered by 6.34 % to 11.88 % when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).
Further, the present invention provides a 100 parts by weight of rubber composition F4, F5, SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler silica gave process safety, MV value lowered by 1.19% to 33.47 % when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).

Also, the present invention provides a 100 parts by weight of rubber composition F1, F2, F3 SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feld spar filler is used as a partial replacement for a reinforcing filler carbon black gave process safety, i.e., t5 value from comparable to 12.82 % improvement (t5 value greater than 18 minutes is ideal value for better processability) when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).

Further, the present invention provides a 100 parts by weight of rubber composition F4, F5, SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler silica gave process safety, t5 value are comparable (t5 value greater than 18 minutes is ideal value for better processability) when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).
Also, the present invention provides a 100 parts by weight of rubber composition F1, F2, F3 SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feld spar filler is used as a partial replacement for a reinforcing filler carbon black gave hardness value ranges from 61 to 62 Shore A.
Further, the present invention provides a 100 parts by weight of rubber composition F4, F5, SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler silica gave hardness value ranges 59 to 60 Shore A.

Also, the present invention provides a 100 parts by weight of rubber composition F1, F2, F3 SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler carbon black gave tensile strength value ranging from 20.18 Mpa to 20.84 Mpa (tensile strength value greater than 15 Mpa is acceptable for general tread compounds) when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).
Further, the present invention disclosure provides a 100 parts by weight of rubber composition F4, F5, SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler silica gave tensile strength value 19.10 Mpa to 20.18 Mpa (tensile strength value greater than 15 Mpa is acceptable for general tread compounds) when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).

Also, the present invention provides a 100 parts by weight of rubber composition F1, F2, F3 SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler carbon black gave Elongation at break value ranging from 579.44% to 592.10% (Elongation at break value greater than 425% is acceptable for general tread compounds) when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).
Further, The present invention provides a 100 parts by weight of rubber composition F4, F5, SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler silica gave Elongation at break value ranging from 556.75 % to 571.74% (Elongation at break value greater than 425% is acceptable for general tread compounds) when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).

Also, the present invention provides a 100 parts by weight of rubber composition F1, F2, F3 SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler carbon black gave high rubber elasticity and it is improved upto 9.87 % when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).
Further, the present invention provides a 100 parts by weight of rubber composition F4, F5, SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for sa reinforcing filler silica gave high rubber elasticity and it is improved by 4.70% to 14.53 % when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).

Also, the present invention provides a 100 parts by weight of rubber composition F1, F2, F3 SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler carbon black provides improved winter traction by 6.57% to 38.03% and rolling resistance lowered by 5.13% to 12.82% when compared to SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).
Further, the present invention provides a 100 parts by weight of rubber composition F4, F5, SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler silica provides improved winter traction by 26.89% to 40.30% and rolling resistance lowered by 5.13% to 13.46% when compared SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).
Hence, the present invention SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler carbon black provides improved winter traction and lower rolling resistance along with optimum tensile strength and elongation at break %, high rubber elasticity and better processability characteristics when compared to SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).
Also, the present invention SBR:PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica and 5 to 20 phr of potash feldspar filler is used as a partial replacement for a reinforcing filler silica provides improved winter traction and lower rolling resistance along with optimum tensile strength and elongation at break %, high rubber elasticity and better processability characteristics when compared to SBR: PBR: NR (40 phr: 30 phr: 30 phr) blend reinforced by carbon black and silica (C1).

Table 2: Characterization of uncured rubber compound and cured rubber vulcanizate
Properties
C1 F1 F2 F3 F4 F5
M1. Hardness, Shore A 62 62 61 61 60 59
M2. Tensile Properties of Rubber Vulcanizate
Tensile Strength, Mpa
(Ideal Value greater than 15 Mpa)
21.71 20.84 20.64 20.18 20.80 19.10
Elongation @ Break % (Ideal value greater than 425 %) 560.10 579.44 588.48 592.10 571.74 556.75
M3. High Rubber Elasticity of Rubber Vulcanizate
M4. Rebound Resilience, 23+/-2 Deg C, % 47.84 48.2 52.56 52.56 50.09 54.79
Rebound Resilience, Index - 100.75 109.87 109.87 104.70 114.53
M5. Dynamic properties of Rubber Vulcanizate
Winter traction, E’ -20 Deg C, Mpa (Lower the index value is better) 33.47 31.27 23.77 20.74 24.47 19.98
Winter traction, E’ – 20 Deg C (Index – Lower the index value is better) - 93.43 71.01 62.15 73.11 59.69
Tan delta @ 60 Deg C 0.156 0.148 0.139 0.136 0.148 0.135
Tan delta @ 60 Deg C (Index) – Lower the index value is better - 94.87 89.10 87.18 94.87 86.54
M6. Mooney Scorch @ 125 Deg C
MV, MU 50.50 47.30 44.50 46.10 49.90 33.60
MV, MU (Index) - 93.66 88.12 91.29 98.81 66.53
T5, min:min 38.22 37.48 41.63 43.12 38.30 37.75
T5, min:min (Index) - 98.06 108.92 112.82 100.2 98.77

In a second aspect of the present invention disclosure, a method preparing a tire tread rubber composition be disclosure. The method include the following steps:
Preparation of I Master Batch includes charging a Banbury mixer with rubbers and homogenizing agent, mixing for 2 to 35 seconds at a head temperature of 65 to 80°C and an unloaded rotor speed of 45 to 60 rpm, sequentially adding carbon black, silica, potash feldspar, process oil, hydrocarbon resin and MC Wax, allowing mixing for 100 to 230 seconds until reaching a temperature of 140 to 145°C. Performing silanization for 60 to 80 seconds at 20 to 30 rpm, then dumping the rubber compound at a temperature range of 150°C to 165°C and sheeting out in a laboratory two-roll mill.
II Master Batch: Adding I master batch, 6PPD, and zinc oxide in a Lab Banbury Mixer, mixing for 60 to 180 seconds, and dumping the rubber compound at a temperature range of 110°C to 135°C, followed by sheeting out in a laboratory
two-roll mill.
III Master Batch: Adding Step II master batch and further mixing for 60 to 180 seconds, then dumping the rubber compound at a temperature range of 110°C to 135°C and sheeting out in a laboratory two-roll mill.
d. Preparation of Final Batch by charging the III master batch rubber
compound into the mixing chamber, allowing it to mix for 10 to 20 seconds and adding accelerators and Vulcanization agent Sulphur, mixing for 60 to 90 seconds, and dumping the rubber compound at a temperature range of up to 95°C to 120°C. Performing final batch sheeting out in a laboratory two-roll mill.
Another aspect of the present invention disclosure, a method preparing a tire tread rubber composition is provided. The method involved the following steps:
Preparation of Master Batch (when there is no silica in the rubber composition) includes charging a Banbury mixer with rubbers and homogenizing agent, mixing for 2 to 35 seconds at a head temperature of 65 to 80°C and an unloaded rotor speed of 45 to 60 rpm, sequentially adding carbon black, potash feldspar, process oil, hydrocarbon resin, stearic acid, MC Wax, 6PPD, Zinc oxide allowing mixing for 100 to 230 seconds until reacting a temperature of 150 to 160°C, then dumping the rubber compound at a temperature range of 150°C to 165°C and sheeting out in a laboratory two-roll mill.
Step II Master Batch: Adding Step I master batch and further mixing for 60 to 180 seconds, then dumping the rubber compound at a temperature range of 110°C to 135°C and sheeting out in a laboratory two-roll mill.
Preparation of Final Batch by charging the Step II master batch rubber
compound into the mixing chamber, allowing it to mix for 10 to 20 seconds and adding accelerators and Vulcanization agent Sulphur, mixing for 60 to 90 seconds, and dumping the rubber compound at a temperature range of up to 95°C to 120°C. Performing final batch sheeting out in a laboratory two-roll mill.
M1. Shore A Hardness:
Shore A Hardness of the Rubber Vulcanizates are assessed in accordance with ASTM D 2240 in Shore A Durometer
M2. Tensile Properties of the Rubber Vulcanizates
Tensile properties of the rubber vulcanizates are measured in accordance with ASTM D 412 in Universal testing machine.
M3. Rubber Elasticity of the Rubber Vulcanizates
Rubber Elasticity of the rubber vulcanizates are measured in accordance with ASTM D 7121 in Rebound Resilience tester, Zwick Roell make.
M4. Dynamic properties of the rubber vulcanizate: The dynamic properties of the rubber vulcanizate are measured on a dynamic mechanical analyzer (DMA Metravib +1000) with a dynamic strain 0.3% and a static strain – 0.6% temperature sweep from - 40 to +80°C, frequency: 10Hz in tension mode as per ASTM D5992.
E’ at – 20 °C is commonly used as a predictor of tyre winter/snow traction. Lower the E’ value at -20°C, better the winter/snow traction.
Tan delta at 60°C is commonly used as a predictor of rolling resistance. Lower the tan delta value at 60°C, lower the rolling resistance.
M5. Better processability (Process Requirements) of a Rubber Compound:
Mooney Scorch Characteristics (pre vulcanization characteristics using large rotor) for processability:
The Mooney Scorch measurements are carried out with a Mooney Viscometer (MV 2000 Alpha technologies, USA) according to ASTM D1646. MV indicates the minimum viscosity, t5 indicates the time to scorch (MV+5) which indicates the processing properties (process safety).