DESC:FIELD OF INVENTION:
The present invention relates to the field of rubber/Polymer Technology. More particularly relates to the tyre casing rubber composition and its method of preparation which improves rubber to cord adhesion properties.
DESCRIPTION OF THE RELATED ART:
The manufacturing process for many rubber products, including tires, includes the step of forming by bonding unvulcanized rubber composition. Rubber-bonded cord structure of a tyre integral with the bead which provides the requisite strength to carry the load. In unvulcanized rubber composition for providing tackiness, the rubber composition, a tackifier may be incorporated. The tackifier usually smaller molecular weight than the rubber component, a glass transition point not exhibit rubber elasticity at room temperature or above resins is used. As the resins, para- tertiary-butylphenol-acetylene resin, alkylphenol resin such as p-octylphenol-formaldehyde resin, aromatic hydrocarbon resin, aliphatic hydrocarbon resin, petroleum resin, such as aliphatic cyclic hydrocarbon resin has been commonly used. A good adhesion between the rubber compound of a tire and the reinforcing polymeric cord after vulcanization is vital for the tire performance and safety. Reference may be made to the following:
Publication no. WO2020202178 provides development of cured elastomeric composite comprising un-modified fuller's earth clay as reinforcing filler and mixing process thereof. Present invention discloses cured elastomeric nanocomposite comprising elastomeric compound 100 phr, with unmodified fuller's earth nano clay 1-200 phr, without any chemical modification imparts high thermal stability, high mechanical properties. The referred patent discusses about the use of unmodified fuller's earth nano clay 1-200 phr without any chemical modification for tyre and non tyre products which imparts high thermal stability, mechanical properties, compression set regulator and hardness modifier whereas the present invention discusses about the use of unmodified fuller's earth nanoclay in tyre casing rubber composition along with naturally occurring resin or any other type of resin to provide better rubber to cord adhesion properties.
Publication no. WO2022101926 & IN202041049202 relates to the field of tires. The present invention discloses a rubber nanocomposite for motorcycle tyre comprising of rubbers, nanofiller as reinforcing filler. The nanofiller are naturally occurring unmodified Fuller’s earth which resulted in reduced rolling resistance and high rubber elasticity. The invention further discloses a method of preparation of the rubber nanocomposite and tyre tread comprising the rubber nanocomposite. The referred patent discusses about the use of unmodified fuller's earth nano clay in tyre tread rubber composition to provide low rolling resistance and high rubber elasticity whereas the present invention discusses about the use of unmodified fuller's earth nanoclay in tyre casing rubber composition along with naturally occurring resin or any other type of resin to provide better rubber to cord adhesion properties.
Publication no. IN202041048775 provides a tyre inner liner nanocomposite and its method of preparation, capable of providing lower modulus, improved barrier and processability characteristics. The rubber composition of tyre inner liner includes 100 phr of rubber selected from natural rubber (NR), non-oil extended styrene butadiene rubber, poly butadiene rubber, reinforcing filler such as carbon black, naturally occurring, unmodified fuller’s earth nanoclay. The referred patent discusses about the use of unmodified fuller's earth nano clay in tyre innerliner rubber composition to provide lower modulus, improved barrier and processability characteristics whereas the present invention discusses about the use of unmodified fuller's earth nanoclay in tyre casing rubber composition along with naturally occurring resin or any other type of resin to provide better rubber to cord adhesion properties.
Publication no. WO2010127117 relates to a hollow glass microsphere and polymer composite having enhanced viscoelastic and rheological properties. The referred patent discusses about the use of hollow glass microsphere (Grade: iM30K) in tyre sidewall rubber composition. The referred patent discusses about the use of hollow glass microsphere (Grade: iM30K) in tyre sidewall rubber composition whereas the present invention discusses about the use of unmodified fuller's earth nanoclay in tyre casing rubber composition along with naturally occurring resin or any other type of resin to provide better rubber to cord adhesion properties.
Publication no. IN201941043079 relates to a rubber composition for bead insulation with improved rubber metal adhesion and compression set comprising Fuller’s earth clay as an adhesion promoter and reinforcing filler. The invention further relates to Bead insulation composition comprising 100 parts by weight of elastomer(s), fuller’s earth clay, preferably acicular in structure, having a length of 10 nm to 5000 nm and without any organic modification at a concentration of 1- 30 parts by weight, calcium carbonate 1-10 parts by weight; carbon black 80-100 parts by weight; 8-20 parts by weight sulphur and a rubber composition consisting of conventional additives and mixing procedure thereof. The referred patent discusses about the use of fuller’s earth nano clay tyre bead insulation rubber composition to provide better rubber to metal adhesion whereas the present invention discusses about the use of unmodified fuller's earth nanoclay in tyre casing rubber composition along with naturally occurring resin to provide better rubber to cord adhesion properties.
OBJECTS OF THE INVENTION:
The principal object of the present invention is to provide a tyre casing rubber composition and its method of preparation.
Another object of the present invention is to provide a tyre casing rubber composition using unmodified fuller's earth nanoclay along with naturally occurring resin.
Yet another object of the present invention is to provide a tyre rubber composition containing unmodified fuller’s earth is to replace reinforcing filler carbon black.
Yet another object of the present invention is to provide tyre casing rubber composition to improve rubber-to-cord adhesion properties.
Yet another object of the present invention is to provide better processing properties.
Yet another object of the present invention is to provide better physical properties.
Yet another object of the present invention is to provide a cost-effective and environmentally friendly tyre casing rubber composition.
Yet another object of the present invention is to provide less carbon footprint.
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 disclosure, a rubber composition for tyre casing is provided.
The rubber composition for tyre casing includes a polymer matrix that includes natural rubber ranging from 60-100 parts per hundred rubber (Phr) of the rubber composition. The rubber composition further includes synthetic rubber that includes styrene-butadiene rubber (SBR) ranging from 0-40 Phr of the rubber composition and polybutadiene rubber (PBR) ranging from 0-40 phr of the rubber composition. The rubber composition further includes homogenizer ranging from 1-2 Phr of the rubber composition. The rubber composition further includes a reinforcing filler such as carbon black ranging from 25-60 Phr of the rubber composition. The rubber composition further includes unmodified fuller’s earth nanoclay with a specific surface area ranging from 100 to 110 m²/g ranging from 5 to 40 parts per hundred rubber (Phr). The rubber composition further includes a resin ranging from 2-10 Phr of the rubber composition and the resin type can be natural resin or C5 resin or C5/C9 resin. The rubber composition further includes mild extracted solvate ranging from 1.0-10 Phr of the rubber composition. The rubber composition further includes an activator (Zinc oxide and stearic acid) ranging from 2-13 phr of the rubber composition. The rubber composition further includes an anti-degradant ranging from 0.5-5 Phr of the rubber composition. The rubber composition further includes a vulcanizing agent ranging from 1.0-3.5 Phr of the rubber composition. The rubber composition further includes a primary accelerator ranging from 1.0-3 Phr of the rubber composition.
In some aspects of the present disclosure, the activator comprising zinc oxide ranging from 2-8 phr and stearic acid ranging from 2-5 phr.
In some aspects of the present disclosure, the anti-degradant is selected from 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ).
In some aspects of the present disclosure, the vulcanizing agent is sulphur.
In some aspects of the present disclosure, the resin is selected from naturally occurring resin, C5 resin, or a C5/C9 resin.
In some aspects of the present disclosure, the process aid is selected from mild extracted solvate (MES) oil.
In some aspects of the present disclosure, the primary accelerator is selected from N-cyclohexyl-2-benzothiazole sulfenamide (CBS).
In some aspects of the present disclosure, the reinforcing filler carbon black has a nitrogen surface area (N2SA) ranging from 73 to 83 m²/gm and an iodine adsorption number ranging from 77 to 87 mg/gm.
In some aspects of the present disclosure, the polymer matrix comprises a triblend elastomer composition in the ratio of 80 parts by weight of natural rubber (ISNR 20), 10 parts by weight of styrene-butadiene rubber (SBR 1502), and 10 parts by weight of high-cis polybutadiene rubber (PBR 1220).
In some aspects of the present disclosure, the unmodified fuller’s earth nanoclay is characterized by acicular particles with diameters of 1-5 nm and lengths of 10-5000 nm, having an aspect ratio ranging from 5 to 45.
In second aspect of the present disclosure, a method for preparing a rubber composition for a tyre casing is provided.
The method includes mixing natural rubber and synthetic rubber, wherein the synthetic rubber is selected from styrene-butadiene rubber (SBR) and high-cis polybutadiene rubber (PBR), in a Banbury mixer at a speed of 50-60 rpm and a temperature between 85°C and 90°C for 20-40 seconds, along with a homogenizer, to ensure uniform mixing of elastomers. The method further includes adding unmodified fuller’s earth nanoclay with a specific surface area ranging from 100 to 110 m²/gm, in an amount of 5 to 40 parts per hundred rubber (Phr), and natural resin in an amount of 2 to 10 Phr, to the polymer matrix and mixing for 60-80 seconds in the Banbury mixer to achieve homogeneous dispersion. The method further includes adding an additional reinforcing filler in an amount ranging from 25 Phr to 60 Phr, and mixing for 50-70 seconds to disperse evenly within the rubber matrix. The method further includes adding processing aid comprising mild extracted solvate (MES) oil, in an amount of 1-10 Phr, along with activators ranging from 2-13 Phr and anti-degradants ranging from 1-2 Phr, and mixing for an additional 50-60 seconds. The method further includes sweeping down the mixture from the sides of the Banbury mixing chamber and allowing it to mix for an additional 50-60 seconds, followed by dumping the compound at a temperature range of 150°C to 165°C. The method further includes sheeting out the rubber compound using a laboratory two-roll mill to form the master batch. The method further includes mixing the master batch compound with the vulcanizing agent, sulfur, in an amount of 1.0-3.5 Phr, and the primary accelerator, in an amount of 1.0-3 Phr, in the Banbury mixer for 50-80 seconds. The method further includes dumping the final rubber compound at a temperature range of 85°C to 110°C. The method further includes sheeting out the final rubber compound using a laboratory two-roll mill to prepare sheets. The method further includes vulcanizing the rubber sheets by heating at a temperature range sufficient for cross-linking the polymer chains, ensuring the development of optimal rubber-to-cord adhesion properties and mechanical strength for use in tyre casing.
In some aspects of the present disclosure, the Banbury mixer is operated at a head temperature of 85°C to 90°C during the initial mixing stage and at a higher temperature range of 150°C to 165°C during the dumping of the master batch compound.
In some aspects of the present disclosure, the unmodified fuller’s earth nanoclay has acicular particles with diameters ranging from 1 to 5 nm and lengths of 10 to 5000 nm, and an aspect ratio of 5 to 45, measured at 50 nm magnification using high-resolution transmission electron microscopy (HR-TEM).

In some aspects of the present disclosure, the rubber composition exhibits improved rubber-to-cord adhesion, tensile strength, and elongation at break as compared to a control composition containing 52 Phr of carbon black as the sole reinforcing filler.
BREIF DESCRIPTION OF THE INVENTION:
The present invention relates to the tyre casing composition and its method of preparation. The tyre produced using a rubber composition of the present invention has better rubber-to-cord adhesion properties. The rubber composition of tyre casing comprises blend of natural rubber and synthetic rubbers along with unmodified fuller's earth nanoclay as a reinforcing filler. The unmodified fuller's earth nanoclay is used in tyre casing rubber composition along with naturally occurring resin to provide better rubber-to-cord adhesion properties.
In one aspect of the present disclosure, a rubber composition for tyre casing is provided. The rubber composition includes a polymer matrix, homogenizer, reinforcing filler, unmodified fuller’s earth nanoclay, resin, mild extracted solvate, activator, anti-degradant, vulcanizing agent, primary accelerator, and process aid.
In some aspects of the present disclosure, the polymer matrix includes natural rubber and a synthetic rubber. In some aspects of the present disclosure, the synthetic rubber includes styrene-butadiene rubber (SBR) and polybutadiene rubber (PBR). In some aspects of the present disclosure, the natural rubber ranging from 60-100 parts per hundred rubber (Phr) of the rubber composition. In some aspects of the present disclosure, the styrene-butadiene rubber (SBR) ranging from 5-15 Phr of the rubber composition. In some aspects of the present disclosure, the polybutadiene rubber (PBR) ranging from 5-15 phr of the rubber composition. In some aspects of the present disclosure, the homogenizer ranging from 0.5-5 Phr of the rubber composition. In some aspects of the present disclosure reinforcing filler such as carbon black ranging from 2-25 Phr of the rubber composition. In some aspects of the present disclosure, the unmodified fuller’s earth nanoclay with a specific surface area ranging from 100 to 110 m²/g ranging from 5 to 25 parts per hundred rubber (Phr).
In some aspects of the present disclosure, the resin ranging from 0.5-5 Phr of the rubber composition.
In some aspects of the present disclosure, the mild extracted solvate ranging from 0.5-5 Phr of the rubber composition.
In some aspects of the present disclosure, the activator ranging from 3-10phr of the rubber composition. In some aspects of the present disclosure, the anti-degradant ranging from 0.5-5 Phr of the rubber composition. In some aspects of the present disclosure, the vulcanizing agent ranging from 0.5-5 Phr of the rubber composition. In some aspects of the present disclosure, the primary accelerator ranging from 0.5-3 Phr of the rubber composition. In some aspects of the present disclosure, the process aid ranging from 2-5 Phr of the rubber composition.
In some aspects of the present disclosure, the activator comprising zinc oxide ranging from 2-6phr and stearic acid ranging from 1-4phr. In some aspects of the present disclosure, the anti-degradant is selected from 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ). In some aspects of the present disclosure, the vulcanizing agent is sulfur. In some aspects of the present disclosure, the resin is selected from naturally occurring resin, C5 resin, or a C5/C9 resin. In some aspects of the present disclosure, the process aid is selected from mild extracted solvate (MES) oil. In some aspects of the present disclosure, the primary accelerator is selected from N-cyclohexyl-2-benzothiazole sulfenamide (CBS). In some aspects of the present disclosure, the reinforcing filler carbon black has a nitrogen surface area (N2SA) ranging from 73 to 83 m²/gm and an iodine adsorption number ranging from 77 to 87 mg/gm. In some aspects of the present disclosure, the polymer matrix comprises a triblend elastomer composition in the ratio of 80 parts by weight of natural rubber (ISNR 20), 10 parts by weight of styrene-butadiene rubber (SBR 1502), and 10 parts by weight of high-cis polybutadiene rubber (PBR 1220).
In some aspects of the present disclosure, the unmodified fuller’s earth nanoclay is characterized by acicular particles with diameters of 1-5 nm and lengths of 10-5000 nm, having an aspect ratio ranging from 5 to 45.
A method for preparing a rubber composition for a tyre casing, in accordance with an aspect of the present disclosure. The method includes the following steps:
In some aspects of the present disclosure, the Banbury mixer is operated at a head temperature of 85°C to 90°C during the initial mixing stage and at a higher temperature range of 150°C to 165°C during the dumping of the master batch compound.
At step 1, mixing natural rubber and synthetic rubber, wherein the synthetic rubber is selected from styrene-butadiene rubber (SBR) and high-cis polybutadiene rubber (PBR), in a Banbury mixer at a speed of 50-60 rpm and a temperature between 85°C and 90°C for 20-40 seconds, along with a homogenizer, Struktol 40MS, to ensure uniform mixing of elastomers.
Further adding unmodified fuller’s earth nanoclay with a specific surface area ranging from 100 to 110 m²/gm, in an amount of 5 to 40 parts per hundred rubber (Phr), and natural resin in an amount of 2 to 10 Phr, to the polymer matrix and mixing for 60-80 seconds in the Banbury mixer to achieve homogeneous dispersion.
In some aspects of the present disclosure, the unmodified fuller’s earth nanoclay has acicular particles with diameters ranging from 1 to 5 nm and lengths of 10 to 5000 nm, and an aspect ratio of 5 to 45, measured at 50 nm magnification using high-resolution transmission electron microscopy (HR-TEM).
Further, adding an additional reinforcing filler in an amount ranging from 25 Phr to 60 Phr, and mixing for 50-70 seconds to disperse evenly within the rubber matrix.
Further, adding processing aid mild extracted solvate (MES) oil, in an amount of 1-10 Phr, along with activator (Zinc oxide and stearic acid) ranging from 2-13 Phr and anti-degradant ranging from 1-2 Phr, and mixing for an additional 50-60 seconds.
Further sweeping down the mixture from the sides of the Banbury mixing chamber and allowing it to mix for an additional 50-60 seconds, followed by dumping the compound at a temperature range of 150°C to 165°C.
Further sheeting out the rubber compound using a laboratory two-roll mill to form the master batch.
At step 2, mixing the master batch compound with the vulcanizing agent, sulfur, in an amount of 1.0 -3.5 Phr, and the primary accelerator, in an amount of 1.0- 3.0 Phr, in the Banbury mixer for 50-80 seconds.
Further, dumping the final rubber compound at a temperature range of 85°C to 110°C and
sheeting out the final rubber compound using a laboratory two-roll mill.
In some aspects of the present disclosure, the rubber composition exhibits improved rubber-to-cord adhesion, tensile strength, and elongation at break as compared to a control composition containing 52 Phr of carbon black as the sole reinforcing filler.
In some aspects of the present disclosure, the activator comprises zinc oxide, zinc complexes, stearic acid, any of the fatty acids, zinc stearate, or combinations thereof.
In some aspects of the present disclosure, the anti-degradant comprises 2,2,4-trimethyl-l,2-dihydroquinoline (TMQ) or any of the types of paraphenyldiamines, secondary aromatic amines, benzimidazoles, or combinations thereof.

Table: 1 Rubber Composition in Phr
Ingredients Control Formulation Formulation related to invention
C1, Phr F1, Phr F2, Phr F3, Phr
ISNR 20 1 80.00 80.00 80.00 80.00
SBR 1502 2 10.00 10.00 10.00 10.00
PBR 1220 3 10.00 10.00 10.00 10.00
Struktol 40 MS 4 1.50 1.50 1.50 1.50
Carbon Black 5 52.00 27.00 32.00 47.00
Unmodified Fullers Earth nano clay 6 25.0 20.0 5.00
Wood Rosin 7 2.50 2.50 2.50
MES Oil 8 3.00 3.00 3.00 3.00
Zinc oxide 9 4.00 4.00 4.00 4.00
Stearic acid 10 2.50 2.50 2.50 2.50
TMQ 11 1.50 1.50 1.50 1.50
Sulphur 12 2.50 2.50 2.50 2.50
CBS 13 1.20 1.20 1.20 1.20
1. The Indian Standard Natural Rubber or natural rubber, ISNR 20 with the Mooney viscosity, ML(1+4)@ 100 Deg C Value ranges from 70 MU to 75 MU from Mamparambil Rubber India Pvt Ltd., India.
2. SBR 1502 – It is a non-oil extended styrene butadiene rubber with the unmassed viscosity, ML(1+4) @ 100°C is in the range of 45 to 55 MU from Reliance Industries Limited, India.
3. PBR 1220 – It is a high cis (>96%) polybutadiene rubber with the Mooney viscosity, ML(1+4)@ 100°C in the range of 40 to 50 MU from Reliance Industries Limited, India.
4. Struktol 40 MS – It is a homogenizer used to improve the homogeneity of elastomers of different viscosity from SCHILL+SEILACHER "STRUKTOL" GMBH, Germany.
5. Carbon Black, N326 –It is the reinforcing filler (HAF) High Abrasion furnace having the iodine adsorption number (IAN No.) value between 77 to 87 mg/gm, oil absorption number (OAN) value between 67 to 77 cc/100gm, compressed oil absorption no. (COAN) value between 63 to 73 cc/100gm, nitrogen surface area (N2SA) value between 73 to 83 m2/gm and the tinting strength value ranges from 106 to 116 % ITRB or any of the carbon black grades which is having the any of the properties as in N326 Carbon black from Himadri Chemicals & Industries Limited, India.
6. Unmodified fuller’s Earth nano clay - It is a reinforcing nano filler with the acicular particles in diameter 1 to 5 nm and length 10 to 5000 nm with the aspect ratio is in the range of 5 to 45 measured in HR TEM image at 50nm magnification from Haritson Mintech Private Limited, India.
7. Wood rosin – It is a natural resin having softening point ranging from 70 to 85 Deg C from Rajsha Chemicals Pvt Ltd., 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. 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.
10. Stearic acid - Stearic acid activates accelerators in presence of zinc oxide forming zinc stearate incitu from 3F industries limited, India.
11. TMQ - It is an antidegradant (2, 2, 4-trimethyl-1, 2-dihydroquinoline (oligomers) from Finorchem Limited, India.
12. Sulphur - It is the vulcanizing agent from The Standard Chemical Co Pvt Ltd., India.
13. CBS - It is a delayed action primary sulfenamide accelerator (N-cyclohexyl-2- benzothiazole sulfenamide). It is a delayed action accelerator suitable for diene rubbers from Noccil Limited., India.
Aprocess of preparation of tyre casing rubber composition is carried out in Banbury Mixer, involving the following mixing steps:
Preparation of master batch: mixing of rubbers, homogenizer struktol 40MS for 20-40 seconds in a mixing chamber at 50 – 60 rpm and head temperature of the Banbury mixer maintained between 85 and 90°C; further adding 100% of the reinforcing nano filler unmodified fuller’s earth, natural resin (wood rosin) and allow it to mix for 60 to 80 seconds; further adding 100% of carbon black reinforcing filler and allow it to mix for 50 to 70 seconds; adding of processing aid MES oil and other rubber ingredients like zinc oxide, stearic acid, antidegradant TMQ and allow it to mix for 50 – 60 seconds; sweeping down in the orifice and allowed to mix for another 50 - 60 seconds; dumping of the compound at temperature range of 150°C to 165°C; sheeting out the rubber compound using laboratory two-roll mill.
Preparation of final batch: Mixing of master batch compound along with the vulcanizing agent sulphur and primary accelerator CBS for 50 – 80 seconds; dumping at a temperature range of 85°C to 110°C; and sheeting out the rubber compound using laboratory two roll mill; wherein the reinforcing filler is unmodified fuller’s Earth nano filler having specific surface area ranging from 102 to 112 m2/gm.
Characterization of unvulcanized and vulcanized Rubber compound:
Measurements and Tests:
M1. Better adhesion properties of reinforcing cord that are bonded to rubber
compounds by H adhesion test procedure.
The H adhesion test measurements are carried out in Universal Testing Machine Instron Make, Model No: 5966 in accordance with ASTM D4776. The tyre cord construction used for H Adhesion test is Nylon 6: N22 1260/2.
M2. The tensile properties of the rubber compound accessed in accordance with ASTM D412.
M2 -A Hardness of Rubber Vulcanizate accessed in accordance with ASTM D2240.
M3. Better Processability 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) and t35 indicates the time to cure (MV+35).
Table 2: Characterization of Cured Rubber Vulcanizate and Uncured Rubber Compound
Control compound Compound related to invention Index Value
SL. No Properties C1
F1
F2 F3 F1 F2 F3
M1 H adhesion Test
Big, Kgf (Higher the index value is better) 12.19 12.79 14.32 12.66 104.92 117.47 103.86
Small, Kgf (Higher the index value is better) 11.36 12.78 11.73 11.37 111.42 102.27 100.00
M2 Physical Properties
Tensile strength, Mpa
(Higher the index value is better) 21.21 21.90 21.66 22.17 103.25 102.12 104.53
Elongation at Break, %
(Higher the index value is better) 498.67 545.63 599.91 525.66 109.42 120.30 105.41
M2- A Hardness, Shore A 64.0 64.0 61.0 64.0 - - -
M3 Mooney Scorch time @ 125 Deg C
t5, minutes: minutes (Higher the index value is better) 34.13
38.83 41.1 34.63 113.77 120.42 101.46
t35, minutes: minutes (Higher the index value is better) 36.62 43.32 45.13 42.76 118.30 123.24 116.77

The present disclosure provides a NR:SBR: BR (80 Phr: 10 Phr: 10 Phr) tribelnd elastomeric rubber composition F1, F2, F3 containing 5 Phr to 25 Phr of unmodified fuller’s earth along with 2.5 Phr of natural resin, Wood Rosin are evaluated against NR:SBR: BR tribelnd elastomeric rubber composition containing 52 phr of N326 carbon black, C1 control rubber composition. The present disclosure provides a NR:SBR: BR (80 Phr: 10 Phr: 10 Phr) tribelnd elastomeric rubber composition F1, F2, F3 containing 5 Phr to 25 Phr of unmodified fuller’s earth along with 2.5 Phr of natural resin, Wood Rosin gave better adhesion property increased by 3.86 to 17.47 % (Big) and comparable to 11.42% (Small) when compared to NR:SBR: BR tribelnd elastomeric rubber composition containing 52 phr of N326 carbon black, C1 control rubber composition.
The present disclosure provides a NR:SBR: BR (80 Phr: 10 Phr: 10 Phr) tribelnd elastomeric rubber composition F1, F2, F3 containing 5 Phr to 25 Phr of unmodified fuller’s earth along with 2.5 Phr of natural resin, Wood Rosin gave higher tensile strength i.e., increased by 2.12% to 4.53 % when compared to NR:SBR: BR tribelnd elastomeric rubber composition containing 52 phr of N326 carbon black, C1 control rubber composition.
The present disclosure provides a NR:SBR: BR (80 Phr: 10 Phr: 10 Phr) tribelnd elastomeric rubber composition F1, F2, F3 containing 5 Phr to 25 Phr of unmodified fuller’s earth along with 2.5 Phr of natural resin, Wood Rosin gave higher elongation at break i.e., increased by 5.41 % to 20.30 % when compared to NR:SBR: BR tribelnd elastomeric rubber composition containing 52 phr of N326 carbon black, C1 control rubber composition.
The present disclosure provides a NR:SBR: BR (80 Phr: 10 Phr: 10 Phr) tribelnd elastomeric rubber composition F1, F2, F3 containing 5 Phr to 25 Phr of unmodified fuller’s earth along with 2.5 Phr of natural resin, Wood Rosin gave hardness value ranging from 61 to 64 Shore A.
The present disclosure provides a NR:SBR: BR (80 Phr: 10 Phr: 10 Phr) tribelnd elastomeric rubber composition F1, F2, F3 containing 5 Phr to 25 Phr of unmodified fuller’s earth along with 2.5 Phr of natural resin, Wood Rosin gave higher elongation at break i.e., increased by 5.41 % to 20.30 % when compared to NR:SBR: BR (80 Phr: 10 Phr: 10 Phr) tribelnd elastomeric rubber composition containing 52 phr of N326 carbon black, C1 control rubber composition.
The present disclosure provides a NR:SBR: BR (80 Phr: 10 Phr: 10 Phr) tribelnd elastomeric rubber composition F1, F2, F3 containing 5 Phr to 25 Phr of unmodified fuller’s earth along with 2.5 Phr of natural resin, Wood Rosin gave higher t5 & t35 values i.e., increased by 1.46 % to 20.42 % & 16.77% to 23.24 % when compared to NR:SBR: BR (80 Phr: 10 Phr: 10 Phr) tribelnd elastomeric rubber composition containing 52 phr of N326 carbon black, C1 control rubber composition.
Hence, the present disclosure provides NR:SBR: BR (80 Phr: 10 Phr: 10 Phr) tribelnd elastomeric rubber composition F1, F2, F3 containing 5 Phr to 25 Phr of unmodified fuller’s earth along with 2.5 Phr of natural resin, wood rosin gave better adhesion properties of rubber compound with tyre cord. Also, NR:SBR: BR (80 Phr: 10 Phr: 10 Phr) tribelnd elastomeric rubber composition F1, F2, F3 containing 5 Phr to 25 Phr of unmodified fuller’s earth along with 2.5 Phr of natural resin, wood rosin gave higher tensile strength and elongation at break along with better processing properties when compared to NR:SBR: BR (80 Phr: 10 Phr: 10 Phr) tribelnd elastomeric rubber composition containing 52 phr of N326 carbon black, C1 control rubber composition. Hence, the present invention provides NR:SBR: BR (80 Phr: 10 Phr: 10 Phr) tribelnd elastomeric rubber composition F1, F2, F3 containing 5 Phr to 25 Phr of unmodified fuller’s earth along with 2.5 Phr of natural resin, wood rosin gave hardness value ranging from 61-64 Shore A.
,CLAIMS:1. A rubber composition for tyre casing, comprising:
a polymer matrix – 100 Phr:
homogenizer - 1-2 Phr;
a reinforcing filler such as carbon black - 25- 60 Phr;
a reinforcing nano filler unmodified fuller’s earth nanoclay – 5- 40 Phr;
a resin - 2-10 Phr;
Process aid – 1.0-10 Phr;
an activator- 2-13 Phr;
an anti-degradant 1.0 – 2.0 Phr;
a vulcanizing agent – 1.0- 3.5 Phr; and
a primary accelerator – 1.0- 3.0 Phr,
wherein unmodified fuller’s earth nano clay with a specific surface area ranging from 100 to 110 m²/gm, wherein the unmodified fuller’s earth nanoclay is characterized by acicular particles having an aspect ratio ranging from 5 to 45, wherein the resin is having the softening point ranging from 70 to 85 Deg C.

2. The rubber composition for tyre casing as claimed in claim 1, wherein the activator comprising zinc oxide ranging from 2-8 Phr and stearic acid ranging from 2-5 Phr.

3. The rubber composition for tyre casing as claimed in claim 1, wherein the anti-degradant is selected from 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ).

4. The rubber composition for tyre casing as claimed in claim 1, wherein the vulcanizing agent is sulfur.

5. The rubber composition for tyre casing as claimed in claim 1, wherein the resin is selected from naturally occurring resin, C5 resin, or a C5/C9 resin.

6. The rubber composition for tyre casing as claimed in claim 1, wherein the process aid is selected from mild extracted solvate (MES) oil.

7. The rubber composition for tyre casing as claimed in claim 1, wherein the primary accelerator is selected from N-cyclohexyl-2-benzothiazole sulfenamide (CBS).

8. The rubber composition for tyre casing as claimed in claim 1, wherein the reinforcing filler carbon black has a nitrogen surface area (N2SA) ranging from 73 to 83 m²/gm and an iodine adsorption number ranging from 77 to 87 mg/gm.

9. The rubber composition for tyre casing as claimed in claim 1, wherein the polymer matrix comprises a triblend elastomer composition in the ratio of 80 parts by weight of natural rubber,10 parts by weight of styrene-butadiene rubber, and 10 parts by weight of high-cis polybutadiene rubber.

10. A method for preparing a rubber composition for a tyre casing, comprising:
At step 1, mixing natural rubber and synthetic rubber, wherein the synthetic rubber is selected from styrene-butadiene rubber (SBR) and high-cis polybutadiene rubber (PBR), in a Banbury mixer at a speed of 50-60 rpm and a temperature between 85°C and 90°C for 20-40 seconds, along with a homogenizer, Struktol 40MS, to ensure uniform mixing of elastomers.
adding unmodified fuller’s earth nanoclay with a specific surface area ranging from 100 to 110 m²/gm, and natural resin to the polymer matrix and mixing for 60-80 seconds in the Banbury mixer to achieve homogeneous dispersion.
adding an reinforcing filler carbon black in an amount ranging from 5 Phr to 25 Phr, and mixing for 50-70 seconds to disperse evenly within the rubber matrix;
adding processing aid comprising mild extracted solvate (MES) oil along with activators Phr and anti-degradants, and mixing for an additional 50-60 seconds;
sweeping down the mixture from the sides of the Banbury mixing chamber and allowing it to mix for an additional 50-60 seconds, followed by dumping the compound at a temperature range of 150°C to 165°C;
sheeting out the rubber compound using a laboratory two-roll mill to form the master batch;
At step 2, mixing the master batch compound with the vulcanizing agent, sulfur and the primary accelerator in the Banbury mixer for 50-80 seconds;
dumping the final rubber compound at a temperature range of 85°C to 110°C;
sheeting out the final rubber compound using a laboratory two-roll mill resulting rubber vulcanizate shore A hardness ranging from 61- 64 Shore A.

11. The method as claimed in claim 1, wherein the Banbury mixer is operated at a head temperature of 85°C to 90°C during the initial mixing stage and at a higher temperature range of 150°C to 165°C during the dumping of the master batch compound.