DESC:FIELD OF INVENTION
The present invention relates to the field of Polymer technology. Particularly, the present invention relates to a tyre rubber composition using natural antidegradant and its method of preparation.
BACKGROUND OF THE INVENTION:
More than 200 types of rubber additives are currently in use, out of which antidegradants are the most important rubber additive in a rubber composition. N- 1, 3-dimethylbutyl-N’-phenyl-phenylenediamine (6PPD) is one of the antidegradants that are widely used all over the world, in particular tire treads, tire
sidewalls, hoses, cables, and seals, as it provides comprehensive protection for rubber, including strong ozone and flex resistance and inhibitory effects towards heat, oxygen, and harmful metals (such as copper), making the rubber products resistant to degradation catalyzed by copper and other heavy metals.
When a tire is exposed to environmental light, high temperature, and ozone for a
long period of time or suffers from chemical corrosion, the tread and sidewall of the tire show some discoloration due to aging of the rubber material, thereby affecting the overall appearance of the vehicle tire. Currently, most tires sold on the market are black; as the rubber raw material do not normally affect the black color in the rubber products, discoloration is less of a concern for producing these
rubber products such as tires in black.
Pollution and discoloration caused by the antidegradants are the most serious among all types of rubber additives in rubber raw materials. Some antidegradants have coloring and polluting effects on the rubber; some antidegradants migrate in the rubber and pollute materials in contact therewith; and some antidegradants cause discoloration in the rubber products during long-term storage, especially under the light. These antidegradants, including the pollution-type antidegradants (such as 4010, 6PPD, IPPD, etc.), are not suitable for producing white and colored products. In some tires with high requirements for the appearance, phenolic antioxidants or saturated rubbers are used to reduce the number of antidegradants and thus discoloration of the tires. Although the use of the phenolic antioxidants may reduce the discoloration of the tires, the anti-aging effect is not as good as the p-phenylene diamine antidegradants and causes great decrease in heat-oxygen resistance, ozone resistance, and flex resistance in tires. Further, although saturated rubbers such as EPDM may be used in tires to reduce the amount of antidegradants to certain degree, or even avoid use of antidegradants at all, to significantly improve the appearance of the tires, it is relatively expensive, so the production cost is greatly increased while its low viscosity causes problems in the adhesion and molding of the tires.
Reference made for the following:
IN Publication No. 202117054503 relates to antidegradant compound of formula and antidegradant composition comprising the same and rubber composition comprising the antidegradant compound or composition. The rubber composition has good resistance to appearance discoloration while maintaining the mechanical and anti-aging properties, thus, are suitable for making the entire tire or as part of the rubber matrix, whereas the present invention discusses the use of natural antidegradant for tyre rubber composition. Both the antidegradants are different from each other.
Publication No. MX2021015414 relates to antidegradant compound of Formula and antidegradant composition comprising the same and rubber composition comprising the antidegradant compound or composition. The rubber composition has good resistance to appearance discoloration while maintaining the mechanical and anti-aging properties, thus, are suitable for making the entire tire or as part of the rubber matrix, whereas the present invention discusses about the use of natural antidegradant for tyre rubber composition. Both the antidegradants are different from each other.
Publication No. CA2078403 relates to a pneumatic tire sidewall and to elastomeric compositions useful therefore. The elastomeric compositions are comprised of natural rubber, polybutadiene, or mixtures thereof; from about 1.0 to 5.0 phr of a precipitated silica filler having a BET surface area of between 100 and 250 square meters per gram and a pH of from 4.0 to 6.5; from about 1.5 to 10.0 phr of an antidegradant selected from the group consisting of amines, phenolic and mixtures thereof, whereas the present invention discusses about the use of natural antidegradant for tyre rubber composition. Both the antidegradants are different from each other.
Publication No. WO2022105742 relates to an antidegradant composition, an antidegradant master batch comprising the antidegradant composition and a rubber composition comprising the antidegradant composition or the antidegradant master batch. The antidegradant composition comprises antidegradant TMPPD and one or two selected from antidegradant N3100-B and an antidegradant N3100-C. The antidegradant composition and antidegradant master batch render a rubber compound and a rubber article excellent discoloration resistance, fatigue resistance, ozone resistance, and mechanical properties before and after thermal oxidative aging and enables the rubber compound to be used in the manufacture of all or part of the rubber matrix, especially as a tire sidewall rubber composition and a tire tread rubber composition, whereas the present invention discusses about the use of natural antidegradant for tyre rubber composition. Both the antidegradants are different from each other.
Publication No. RU2015126656 relates to rubber composition for a tyre sidewall contains a natural or synthetic rubber polymer, an antidegradant causing plaque formation, and a polyester which comprises a copolymer of maleic anhydride or acid and a linear or branched polyol in an amount of approx. 0.1 wt. parts to approx. 10 wt. parts per 100 wt. parts of rubber. Invention can improve gloss and the quality of the rubber composition of under tyre operating conditions while maintaining high ozone resistance, whereas the present invention discusses about the use of natural antidegradant for tyre rubber composition.
Publication No. WO9906480 relates to concerns a white, light-colored or colored rubber composition, devoid of carbon black, usable for making color tyres or rubber articles designed for such tyres, comprising at least a diene elastomer, a reinforcing white or colored filler, and an antidegradant, photo stable and non- staining relative to said composition, consisting of a N-phenyl-maleimide derivative of formula in which: R<1> and R<2>, identical or different, represent hydrogen or a halogen; Ph represents a phenyl group, substituted or not; Are represents an aryl group, substituted or not, with 6 to 12 carbon atoms, whereas the present invention discusses about the use of natural antidegradant for tyre rubber composition. Both the antidegradants are different from each other.
Publication No. JP2021001335 relates to antidegradant and antifatigue efficacy that are useful as an additive for vulcanized rubber articles, vulcanizable elastomeric formulations, lubricants, fuels, fuel additives, and other compositions which require such efficacy. An antidegradant composition comprises N, N’- (butane-2, 3-diyl) bis (N-phenylbenzene-1, 4-diamine). A lubricant composition further comprises a lubricant. A vulcanizable elastomeric formulation comprising an elastomer and the antidegradant composition. A vulcanized elastomeric article being a vehicle tire comprises at least one component formed from the vulcanizable elastomeric formulation, whereas the present invention discusses about the use of natural antidegradant for tyre rubber composition. Both the antidegradants are different from each other.
Publication No. US2019264010 relates to a rubber composition in which static ozone resistance, dynamic ozone resistance and discoloration resistance are highly balanced. Also provided is a tire in which static ozone resistance, dynamic ozone resistance and discoloration resistance are highly balanced. The rubber composition comprises a rubber component, a petroleum wax, and an antidegradant, wherein the petroleum wax comprises a C20-C34 hydrocarbon component and a C35 or higher hydrocarbon component, and a proportion of the C20-C34 hydrocarbon component is 15% by mass to 30% by mass and a proportion of the C35 or higher hydrocarbon component is 70% by mass to 85% by mass, based on a total mass of the C20-C34 hydrocarbon component and the C35 or higher hydrocarbon component, whereas the present invention discusses about the use of natural antidegradant for tyre rubber composition. Both the antidegradants are different from each other.
Publication No. WO2019156093 relates to a rubber composition having low exothermicity, excellent wear resistance, and excellent workability, the present invention is characterized by comprising: a rubber component containing a diene-based rubber; a filler; a compound represented by formula; and an antidegradant containing a compound having a phenol group, whereas the present invention discusses about the use of natural antidegradant for tyre rubber composition. Both the antidegradants are different from each other.
Publication No. CN107286394 relates to a rubber composition with low resin crosslinking and a method. Specifically, tire components comprising rubber compositions based upon cross-linkable elastomer composition, the cross-linkable elastomer compositions include, per 100 parts by weight of rubber (phr), a highly unsaturated diene elastomer, a reinforcing filler, and a methylene acceptor of the form wherein R is selected from H, an alkyl moiety, a cycloalkyl moiety, an 1aryl moiety, an amine moiety or combinations thereof. The rubber compositions include a methylene donor in an amount that provides little or no change in the rigidity of the cured rubber composition. Since the methylene acceptor may be described as having antidegradant properties, then resulting rubber composition has improved resistance to degradation, whereas the present invention discusses about the use of natural antidegradant for tyre rubber composition. Both the antidegradants are different from each other.
Publication No. KR101364781 relates to a rubber composition for a tire with improved anti-aging properties, and more specifically, to a rubber composition for a tire in which, as an antioxidant, a mixture of 4,4'-bis (alkyl amino) diphenylamine (BAADA) and N-(1,3-dimethyl butyl)-N'-phenyl-p-phenylene diamine (6PPD) and a particular filling material are comprised in raw rubber with a certain content ratio. A rubber composition for a tire of the present invention has superior physical properties which are required as a tire rubber and also has improved anti-aging performance and thermal stability, and especially sufficient time for a vulcanization process is secured because a scotch time is long in rubber compounding, whereas the present invention discusses about the use of natural antidegradant for tyre rubber composition. Both the antidegradants are different from each other.
Publication No. US2012097302 relates to a tread band and tire having a tread band bonded thereto, particular embodiments including a tread band having an antidegradant reservoir forming a part of the tread band and having a rubber composition mixed with an antidegradant at a higher antidegradant concentration than an adjacent rubber composition with the antidegradant reservoir being in diffusive communication with the base surface of a tread shoulder. The tread band may further include a barrier layer separating at least a portion of the antidegradant reservoir from the adjacent rubber composition Particular embodiments include a tread band having an antidegradant reservoir forming a part of the tread band, the antidegradant reservoir comprising a rubber composition mixed with an antidegradant and a barrier layer bordering at least a portion of the antidegradant reservoir, wherein the barrier layer inhibits diffusion of the antidegradant from the antidegradant reservoir through the barrier layer, whereas the present invention discusses about the use of natural antidegradant for tyre rubber composition. Both the antidegradants are different from each other. Publication No. US2011095106 relates to a method comprising reducing the size of elastomeric particles in the presence of a liquid, wherein said liquid comprises an antidegradant and optionally a surfactant. Further provided is a method comprising bringing elastomeric particles into contact with a liquid, wherein said liquid comprises an antidegradant and, optionally, a surfactant. Also provided is an elastomeric particle that is created from an original elastomeric piece, where said elastomeric particle has an antidegradant concentration greater than that of the original elastomeric piece. Further provided is a rubber composition comprising elastomeric particles. Additionally, the disclosure provides a tire containing a rubber composition that comprises the elastomeric particle, whereas the present invention discusses the use of natural antidegradant for tyre rubber composition. Both the antidegradants are different from each other.
Publication No. US8207247 relates to the processes for mixing a filler with a rubber blend containing at least one isoprene elastomer and one butadiene elastomer are provided. Preferably, the processes include the steps of combining elastomers or a blend of elastomers, a carbon black and/or silica filler(s) and a Quinone diamine antidegradant in a rubber composition; mixing the rubber composition for a viscosity-reducing effective period of time to reduce the viscosity of the composition; and discharging the mixed composition. The compositions are preferably discharged from the mixing vessel at or near a minimum viscosity occurring at a temperature of about 120-160° C, whereas the present invention discusses about the use of natural antidegradant for tyre rubber composition. Both the antidegradants are different from each other.
Publication No. KR20100002779 relates to a tire rubber composition to ensure properties similar to or more than conventional rubber compositions by comprising N-(1.3-dimethylbutyl)-N'-phenyl-p-phenylene diamine and to maintain antioxidation and anti-aging property even though an anti-aging agent is reduced. A tire rubber composition with anti-aging property comprises a base rubber 100.0 parts by weight and (N-(1.3-dimethylbutyl)-N'-phenyl-phenylene diamine) -(4, 4’-bis (alkyl amino) diphenylamine) represented by chemical formula (1). The (N-(1.3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) -(4,4'-bis (alkylamino) diphenylamine) of chemical formula (1) is obtained by reacting N- (1.3-dimethylbutyl)-N'-phenyl-phenylene diamine 1 mole with 4,4'-bis (alkyl amino) diphenylamine 2 moles at 20-30 °C and 100-500 rpm for 1-3 hours. Publication No. KR20100002735 relates to a tire rubber composition to ensure the properties similar to or more than conventional rubber compositions, to maintain anti-aging property and antioxidation caused by flection and ozone, and to prevent appearance pollution. A tire rubber composition comprises 100.0 parts by weight of a base rubber and 0.25~4 parts by weight of (N'-isopropyl-N-phenyl-p- phenylene diamine) -(4, 4’-bis (alkyl amino) diphenyl amine) represented by chemical formula (1). The (N'-isopropyl-N-phenyl-phenylene diamine) -(4, 4’- bis (alkyl amino) diphenylamine) of chemical formula (1) is obtained by reacting 3PPD (N'-isopropyl-N-phenyl-phenylene diamine) and (4,4'-bis (alkyl amino) diphenylamine), whereas the present invention discusses the use of natural antidegradant for tyre rubber composition. Both the antidegradants are different from each other.
Publication No.US2008128060 relates to a rubber composition containing a diene-based elastomer reinforced with rubber reinforcing carbon black and/or silica which contains an antidegradant comprised of N-1,3-dimethylbutyl-N'- phenyl-p-phenylene diamine (6-PPD) together with a dispersion of a methyl isobutyl ketone (MIBK)-adsorbing activated carbon. The invention further relates to a tire having a component thereof containing such rubber composition, whereas the present invention discusses about the use of natural antidegradant for tyre rubber composition. Both the antidegradants are different from each other.
IN Publication No. 3926/CHE/2013 relates to a rubber composition comprising a hybrid elastomeric base, carbon black having an average particle size of 20-50 nm, one or more peptizing agents, one or more activators, one or more antioxidants, vulcanizing agent, a vulcanization accelerator, and pre-vulcanized inhibitor, wherein the ratio of the natural rubber to the butadiene rubber in the composition ranges between 70:30 to 80:20. The rubber compositions of the present invention has good durability, and very good tensile and elongation and other properties, whereas the present invention discusses about the use of natural antidegradant for tyre rubber composition. Both the antidegradants are different from each other.
IN Publication No. 7046/CHENP/2009 relates to processes for mixing a filler with a rubber blend containing at least one isoprene elastomer and one butadiene elastomer are provided. Preferably, the processes include the steps of: combining elastomers or a blend of elastomers, a carbon black and/or silica filler(s) and a Quinone diamine antidegradant in a rubber composition; mixing the rubber composition for viscosity, reducing effective period of time to reduce the viscosity of the composition; and discharging the mixed composition. The compositions are preferably discharged from the mixing vessel at or near a minimum viscosity occurring at a temperature of about 120-160°C, whereas the present invention discusses about the use of natural antidegradant for tyre rubber composition. Both the antidegradants are different from each other.

6PPD in tires is converted to 6PPD-quinone (6PPD-q) when exposed to ozone. 6PPD-q is contained in tire wear particles that can be transported in the air and potentially inhaled by people. The particles can also be deposited on surfaces, soils, and plants, including foods, leading to potential plant uptake and human dermal exposure and ingestion. Tire wear particles can also stay near the roadway and be transported to surface waters through stormwater drains and runoff. 6PPD-q in surface waters can be ingested and absorbed by fishes. Exposed organisms can be ingested by humans and other species. 6PPD-q can potentially be mitigated by green stormwater infrastructure. Research is ongoing to further define 6PPD-q’s environmental behaviors, exposures, and the potential development of adverse health outcomes. Both 6PPD and 6PPD-q surpass the threshold for very high acute aquatic toxicity using the Globally Harmonized System of Classification and Labeling of Chemicals. 6PPD is also listed as a category 1B reproductive toxicant by the European Chemicals Agency (ECHA).
However, a non-pollution-type antidegradant that may replace 6PPD in all aspects has not yet been developed.
In order to overcome the above listed prior arts, the present invention aims to provide a tyre rubber composition using natural antidegradant and its method of
preparations.
OBJECTS OF THE INVENTION:
The principal object of the present invention is to provide a tyre rubber composition using natural antidegradant and its method of preparation.
Another object of the present invention is to provide a tyre rubber composition using natural antidegradant which is not hazardous.
Yet another object of the present invention is to provide a rubber composition for tyre tread, particularly as a natural antidegradant.
Yet another object of the present invention is to provide cost effectiveness.
Yet another object of the present invention is to provide an environmental friendly tyre tread rubber composition.
Yet another object of the present invention is to provide alternate material to 6PPD.
Yet another object of the present invention is to optimum tensile properties and hardness.
Yet another object of the present invention is to provide better aging properties and to provide an improved ozone crack resistance along with better processability characteristics.
At the outset of the description that follows, it is to be understood that the ensuing description only illustrates a particular form of this invention. However, such a particular form is only an exemplary embodiment and is not intended to be taken restrictively to imply any limitation on the scope of the present invention.
SUMMARY OF THE INVENTION:
In one aspect of the present invention, it pertains to a tire rubber composition using natural antidegradants and its preparation method thereof.
In another aspect of the present invention, the composition includes elastomeric matrix, carbon black for reinforcing filler, activators (Zinc oxide and stearic acid or zinc stearate), lignin as antidegradant, microcrystalline wax, process oil, vulcanization agents, primary and secondary accelerators.
In an aspect of the present invention, the natural antidegradants such as tannin are obtained from renewable resources used in place of commercially available chemical antidegradants in the tyre tread rubber composition.
In an aspect of the present invention, the rubber composition for tyre tread contains 100 parts per hundred rubber (phr) comprising both natural and synthetic rubbers, the selection of synthetic rubbers can be from SBR having Tg values ranging from -21 to -50 Deg C and the SBR can be from solution or emulsion polymerized techniques, Oil extended or non-oil extended SBR , functionalized SBR, , polybutadiene rubber, polybutadiene rubber catalyzed by Neodymium or lithium or combinations thereof, 30-80 phr of reinforcing filler and the reinforcing fillers can be from ASTM grades N110, N121, N134, N234, N220, N231, N330, N339, N347, N375, N326, N550, N660 and the combinations thereof, inorganic fillers, functionalized organic or inorganic fillers etc., and 0.1-10 phr of tannin as a natural antidegradant. Those who are skilled in art can use tannin as a natural antidegradant can be used along with different type of microcrystalline wax.
Also, tannin as a natural antidegradant can be used along or partially replaced with other amine or phenolic antioxidants.
Process aid can be selected from MES oil or TDAE oil or RAE oil or resins type of C5 or C5/C9 or hydrocarbon resin or combination thereof.
Accelerators can be from delayed action sulfenamides, thiazoles, thiuram sulfides, dithiocarbonates and guanidine’s. Vulcanizer can be from soluble or insoluble sulphur.
In an aspect of the present invention, the rubber composition for tyre tread provides sustainability, improved aging properties, and enhanced processing properties in tire manufacturing.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1 represents the SEM image of Natural Antidegradant Tannin at 10 µm and it clearly depicts the multiphase material and the embedded particles presence on it.
Figure 2 represents the SEM image of Natural Antidegradant Tannin at 10 µm in 500 X Magnification and it shows embedded particles are spherical.
Figure 3 represents the SEM image of Natural Antidegradant Tannin at 1 µm in 20.00 K X Magnification and it shows closure view of spherical particles.
Figure 4 represents the SEM image of Natural Antidegradant Tannin at 200 nm in 40.00 K X Magnification and it shows closure view of spherical particles are embedded with needle shape particles.
Figure 5 represents the SEM image of Natural Antidegradant Tannin at 200 nm in 40.00 K X Magnification and it shows a closure view of spherical particles are embedded with a different sizes of needle shaped particle.
DETAILED DESCRIPTION OF THE INVENTION:
The present invention relates to the tyre rubber composition using natural antidegradant and its method of preparation. Natural antidegradant such as tannin is obtained from renewable resources used in place of commercially available chemical antidegradants in tyre tread rubber composition.
The composition for tyre treads comprises an elastomeric matrix carbon black as a reinforcing filler; activators; tannin as antidegradant; microcrystalline wax; process oil; vulcanization agent; primary and secondary accelerators.

Table 1: Tread rubber composition in Phr

Ingredients Comparative Example C1, Phr Examples related to invention, Phr
F1, Phr F2, Phr F3, Phr
ISNR 20 1 45.00 45.00 45.00 45.00
SBR 2 45.00 45.00 45.00 45.00
PBR 3 10.00 10.00 10.00 10.00
Carbon Black 4 55.00 55.00 55.00 55.00
MES Oil 5 10.00 10.00 10.00 10.00
Zinc oxide 6 3.00 3.00 3.00 3.00
Stearic acid 7 2.00 2.00 2.00 2.00
6 PPD 8 1.50 - - -
Natural Antidegradant, Tannin 9 - 0.50 0.75 1.25
DPG 10 1.00 1.00 1.00 1.00
CBS 11 1.50 1.50 1.50 1.50
Sulphur 12 1.60 1.60 1.60 1.60

1- ISNR 20-Indian Standard Natural Rubber ISNR 20 with the Mooney Viscosity, ML (1+4) at 100°C is 76 MU.
2- SBR -HPR 355 HR is non-oil extended solution styrene butadiene rubber (SSBR) with 26 – 28 % of styrene content, 55.5 % to 59.5% of vinyl content and
Tg of -21°C to -27°C (HPR 355 HR from JSR corporation).
3- PBR – Poly butadiene Rubber PBR 1220 with the Mooney Viscosity, ML (1+4) at 100°C ranging from 40 MU to 50 MU from Reliance Industries Limited, India
4- Carbon Black-ASTM Grade N330 from Himadri Carbon, India. It is the reinforcing filler HAF, High Abrasion Furnace having the Iodine adsorption No. 77 to 87 mg/gm, tinting strength value between 99 to 109 % ITRB, nitrogen surface area value between 73 to 83 m2/gm and COAN value ranges between 83 to 93 cc/100 gm.
5- MES oil– Mild Extracted Solvate or Low PCA oil is used to improve the processability of rubber compounds from IOCL Limited, India.
6- 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.
7- 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.
8- 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.
9- Natural Antidegradant, Tannin – Tannin or Cutch Tannin powder is an antidegradant derived from renewable resources having greater than 60% tannins by mass and it is characterized by SEM EDS i.e., scanning electron microscopy (SEM) equipped with an energy-dispersive spectroscopy (EDS) system for elemental analysis and the presence of main elements in weight % is as Oxygen content (O K) is 76.48%, Sodium content (Na K) is 13.67%, Potassium content (K K) is 4.07%, etc., is obtained from Agrosyn Impex, Reg.office: 374/1 Sarodhi Tighra Road Sutrai Falia, Village: SARODHI;Taluka – Pardi; District – Valsad; Gujarat 396185 India.
10- DPG - DiphenylguanidineIt is secondary accelerator, used to activate the primary accelerator) from PMC Rubber Chemicals India Pvt ltd, India.
11-CBS- (N-cyclohexyl-2-benzothiazolesulfenamide) It is a delayed action accelerator suitable for diene rubbers from Nocil Limited, India.
12- Sulphur is the vulcanizing agent from The Standard Chemical Co. Pvt Ltd, India.

Method of preparation of natural antidegradant containing tyre tread rubber
composition is as follows:
A) Preparation of Master batch:
Preparation of master batch has been performed with the rotation speed of the mixer between 50 to 60 rpm and with the head temperature of the Banbury mixer with a tangential rotor maintained between 70 to 80°C.
i) Mixing chamber has been charged with the polymers and allowed to mix for 0 to 70 seconds,
ii) Addition of the reinforcing filler carbon black, Process oil, zinc oxide, stearic acid, tannin as antidegradant, and allowed to mix for 120 to 196 seconds,
iii) Sweeping down in the orifice and allowed to mix for 102 to 130 seconds and the masterbatch rubber compound has been dumped.
The masterbatch rubber compound has been sheeted out in the laboratory two-roll mill.
B) Preparation of final batch:
Mixing chamber charged with the master batch and the curatives namely sulphur, accelerators are added, and allowed to mix for 50 to 90 seconds and dumped at the temperature range of 85°C to 115°C.
Final batch sheet out has been done in the laboratory two roll mill.
Characterization of unvulcanized and vulcanized Rubber compound:
Measurements and Tests:
Better processability (Process Requirements) of a Rubber Compound:
M1. Mooney Viscosity for processability:
The Mooney Viscosity are carried out with a Mooney Viscometer (MV 2000 Alpha technologies, USA) according to ASTM D1646. MV indicates the minimum viscosity, which indicates the processing properties.
M2. Physical Properties of Rubber Vulcanizate
Tensile properties of the rubber compound are accessed in accordance with ASTM D412
M3. The ageing properties were evaluated in accordance with ASTM D 573/ ASTM D412. The dumbbell test specimens were aged at 70 Deg C for 168 hrs and 100 Deg C for 72 hrs hot air ageing oven.
M4. Shore A Hardness of the Rubber Vulcanizate measured in accordance with ASTM D 2240.
M5. Ozone resistance is measured in accordance with ASTM D 1149 and the test conditions are Ozone Concentration: 50 pphm; Temp: 40°C; Duration: 48 hrs & 200 hrs; Strain: 20%
Table 2: Characterization of Uncured rubber Compound and Cured Rubber Vulcanizate
Sl.No. Properties Control, C1 F1 F2 F3 F1,
Index F2,
Index F3,
Index
M1 Mooney Viscosity at 125 Deg C, MU (Rubber final batch compound less than 55 MU provides better processability) 48.0 47.4 50.7 46.9 - - -
M2 Physical Properties of the Rubber Vulcanizate
Tensile strength, mpa (Higher the index value is better) 19.80 20.63 20.43 20.36 104.1 103.1 102.8
M3 Ageing Properties: Change in Tensile Strength, MPa
Aged at 100 deg C/ 72 hrs, mpa (Higher the index value is better) -5.40 -5.40 -2.06 -5.34 100.0 161.9 101.1
Aged at 70 Deg C/ 72 hrs, mpa (Higher the index value is better) -0.42 -0.38 +1.33 +1.35 109.5 316.7 321.4
M4 Hardness, Shore A 63 64 65 65 - - -
M5 Ozone resistance, 48 hrs No crack upto 48 hrs No crack upto 48 hrs No crack upto 48 hrs No crack upto 48 hrs - - -
Ozone resistance, 200 hrs
Crack area % measured through Image J Software (Higher the index value is better) 15.782 15.386 14.288 13.360 102.5 109.5 115.4

The purpose of these tests is to measure the rubber compound properties of the rubber compositions related to invention F1, F2, F3, against the control composition, C1. Three rubber compositions based on NR:SBR:BR formulation, reinforced by carbon black containing 0.1-10 phr of tannin as natural antidegradant against NR:SBR:BR based formulation reinforced by carbon black containing 1.5 phr 6PPD (Control, C1) are prepared and evaluated.
The present invention provides 100 parts by weight of rubber compositions F1, F2, F3 NR:SBR:BR tri blend based rubber composition containing 0.1-10 phr of antidegradant gave Mooney Viscosity in the range of 46.9 MU to 50.7 MU when compared to NR:SBR:BR triblend based rubber composition with a 1.5 phr of 6PPD antidegradant, C1 (Control) having Mooney Viscosity 48 MU. Note: Mooney Viscosity lesser than 55 MU provides better processing characteristics of rubber compound.
The present invention provides 100 parts by weight of rubber compositions F1, F2, F3 NR:SBR:BR tri blend based rubber composition containing 0.1-10 phr of antidegradant gave higher tensile strength increased by 2.8% to 4.1% when compared to NR:SBR:BR based rubber composition with an antidegradant, C1 (Control).
The present invention provides 100 parts by weight of rubber composition F1, F2, F3 NR:SBR:BR tri blend based rubber composition containing 0.1-10 phr of antidegradant as tannin gave comparable to 61.9% improvement in aged tensile strength properties in 70 Deg C at 168 hrs when compared to NR:SBR:BR based rubber composition with 1.5 phr of antidegradant 6PPD, C1 (Control).
The present invention provides 100 parts by weight of rubber composition F1, F2, F3 NR:SBR:BR tri blend based rubber composition containing 0.1-10 phr of antidegradant as tannin gave 9.5% to 221.4% improvement in aged tensile strength properties in 100 Deg C at 72 hrs when compared to NR:SBR:BR based rubber composition with 1.5 phr of antidegradant 6PPD, C1 (Control).
The present invention provides a 100 parts by weight of rubber composition F1, F2, F3 NR:SBR:BR tri blend based rubber composition containing 0.1-10 phr of antidegradant as tannin gave 64 to 65 Shore A Hardness when compared to NR:SBR:BR tri blend based rubber composition with 1.5 phr of antidegradant 6PPD, C1 (Control) having hardness of 63 Shore A.
The present invention provides 100 parts by weight of rubber composition F1, F2, F3 NR:SBR:BR tri blend based rubber composition containing 0.1-10 phr of antidegradant as tannin provides no ozone crack upto 48 hrs which is similar to no ozone crack phenomenon upto 48 hrs as in NR:SBR:BR triblend based rubber composition with 1.5 phr of antidegradant 6PPD, C1 (Control).
The present invention provides 100 parts by weight of rubber composition F1, F2, F3 NR:SBR:BR tri blend based rubber composition containing 0.1-10 phr of antidegradant as tannin gave 2.5% to 15.4% improvement in ozone crack resistance at 200 hrs when compared to NR:SBR:BR based rubber composition with 1.5 phr of antidegradant 6PPD, C1 (Control).
Hence, the present invention provides 100 parts by weight of rubber composition, NR:SBR:BR triblend based rubber composition containing 0.1 to 10 phr of natural antidegradant provides higher tensile strength, higher hardness, improved ageing properties, better ozone resistance along with better processibility characteristics when compared to NR: SBR:BR triblend based rubber composition containing 1.5 phr of 6PPD as antidegradant.
Figures 1-5 relates to the use of natural antidegradants, specifically tannin, in the tyre tread rubber composition, which significantly enhances its durability and environmental impact. Figure 1 shows the SEM image of natural antidegradant tannin at 10 µm, highlighting its multiphase material and the embedded particles on the surface. Figure 2 focuses on the tannin structure at 500X magnification, where spherical particles are clearly visible, contributing to its antioxidant properties in the rubber matrix. Figures 3 and 4 depict higher magnification (up to 40K X) and show the interaction between spherical and needle-shaped particles in the natural tannin. This structure ensures a consistent bond between the rubber and the fillers, improving ozone and aging resistance. Figure 5 further elaborates on the particle distribution at the nano-level, reinforcing the conclusion that tannin-based antidegradants enhance performance while being environmentally friendly.
In the context of the present invention, as illustrated in Figures 1-5, the unique structural characteristics of the tannin particles, as observed in the SEM images, serve as a critical aspect of the tyre tread rubber composition. The incorporation of tannin, which exhibits both spherical and needle-shaped particles at various magnifications, significantly enhances the rubber matrix's ability to resist oxidative and thermal degradation. This structural integrity of tannin particles, as observed in Figures 3 and 4, allows for improved interfacial adhesion between the rubber and the reinforcing fillers, thereby reducing the need for conventional chemical antidegradants like 6PPD. Furthermore, the nano-scale distribution of these particles, as highlighted in Figure 5, ensures uniform dispersion within the elastomer matrix, thus contributing to improved tensile strength, hardness, and ozone resistance over an extended period. The natural origin of tannin further provides environmental benefits by reducing toxic emissions typically associated with synthetic antidegradants, while maintaining or exceeding the performance standards required for tyre tread rubber compositions. The SEM characterization in these figures effectively demonstrates the potential for tannin to serve as a robust and sustainable alternative to synthetic chemical antidegradants.
ADVANTAGES:
a) Natural antidegradant are obtained from renewable
resources.
b) Natural antidegradant tannin is used to provide better aging properties, ozone resistance along with better processing properties.
c) Elimination of 6PPD by using natural antidegradant tannin can save environment.
d) Cost effective.
e) Natural antidegradant tannin can be used in tyre rubber compositions of different tyre components like tread, sidewall, casing, innerliner, bead insulation, bead apex etc.,
,CLAIMS:1. A tyre tread rubber composition comprising:
Elastomeric matrix - 100 phr
Tannin as a natural antidegradant -0.1 -10 phr
Reinforcing carbon filler black - 30-80 phr
Process aid -0-10 phr
Activator - 1-5 phr
Sulphur - 1.2 -3 phr
Primary accelerators - 1-3.0 phr
Secondary accelerator -0-3.0 phr
wherein the natural antidegradant tannin having the presence of main elements in weight % is as Oxygen content (O K) is 76.48%, Sodium content (Na K) is 13.67%, Potassium content (K K) is 4.07%,
2. The tyre tread rubber composition as claimed in claim 1, wherein the reinforcing filler carbon black is selected from any of (American Society for Testing and Materials) ASTM grades its and combination thereof.
3. The tyre tread rubber composition as claimed in claim 1, wherein the natural antidegradant tannin is derived from renewable resources and is characterized by scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS).
4. The tyre tread rubber composition as claimed in claim 1, wherein the elastomeric matrix consists of natural rubber, solution polymerized styrene butadiene rubber and polybutadiene rubber (NR:SBR:BR) in a blend ratio of 45 phr: 40 phr: 10 phr.
5. The tyre tread rubber composition as claimed in claim 1, wherein tannin can be used alone or in combination with other amine or phenolic antioxidants or microcrystalline wax types.
6. A method for preparing a tyre tread rubber composition using tannin as a natural antidegradant, comprising:
charging the mixing chamber of a Banbury mixer with natural and synthetic rubbers, and allowing to mix for a time period of 0 to 70 seconds at a temperature of 70 to 80°C and rotor speed of 50 to 60 rpm;
adding reinforcing fillers, tannin, and process oil, and mixing for 120 to 196 seconds;
adding activators including zinc oxide and stearic acid, and mixing for 102 to 130 seconds, followed by sweeping down and dumping at 85 to 115°C;
sheeting out the masterbatch on a two-roll mill;
adding curatives including sulfur, primary accelerators, and secondary accelerators, and mixing for 50 to 90 seconds;
dumping the final batch at 110 to 130°C; and
sheeting out the final batch using a two-roll mill.
7. The method as claimed in claim 8, wherein the process involves two-stage mixing, including a masterbatch and a final batch with curatives.
8. The tyre tread rubber composition as claimed in claim 1, wherein the final batch exhibits a Mooney viscosity of less than 55 MU, ensuring enhanced processability, and demonstrates a tensile strength increase ranging from 2.8% to 4.1% over compositions utilizing 6PPD as an antidegradant, wherein tannin, employed as a natural antidegradant, further enhances the composition by improving aging resistance, ozone resistance, and overall processability.
9. The tyre tread rubber composition as claimed in claim 1, wherein the activator is the combination of zinc oxide and stearic acid or zinc stearate.
10. The tyre tread rubber composition as claimed in claim 1, wherein the process aid can be from MES oil or TDAE Oil or RAE Oil or any of the resin types selected from C5, C5/C9, hydrocarbon resin and its combination thereof.
11. The tyre tread rubber composition as claimed in claim 1, wherein the primary accelerators can be selected from sulfenamide types and secondary accelerator can be selected from guanidine types and the vulcanizer can be selected from soluble or insoluble sulphur.