DESC:FIELD OF INVENTION:
The present invention relates to the field of Polymer technology and for tyre tread rubber composition. More particularly, relates to a tire tread rubber composition using rice husk-based silica as a renewable reinforcing filler.
DESCRIPTION OF THE RELATED ART:
Rice husk or paddy husk - an agricultural residue is available abundantly in rice producing countries. India alone produces approximately 12 million tons of rice husk annually. Rice husk is generally not advocated as cattle feed because of low cellulose and other sugar contents in it. Furfural and rice bran oil are extracted from rice husk. Rice husk is used by industries as fuel in boilers and for power generation. Rick husk has a high ash content varying from 18-20%. Silica is the major constituent of rice husk ash. High silica (SiO2) content in rice husk ash is economically feasible to extract silica, which has wide market. The process also addresses the issue of appropriate disposal of rice husk ash. The strength of this novel process of extracting silica through precipitation is that with minor changes in the chemical composition the end product silica could be used for various applications.
Reference made to the following:
Publication No. CN102212219B relates to a rice-husk-based carbon/silicon composite used as a rubber filler and a preparation method thereof and belongs to the technical field of the preparation of carbon/silicon fillers. The referred patent discusses the rice husk-based carbon/silica filler in rubber composition but does not provide anything related to silica obtained from rice husk in tyre tread rubber composition.
Publication No. IN202241028226 relates to the eco-friendly concrete paver blocks prepared with Fly Ash (FA), Rice Husk Ash (RHA) substituted as partial replacement to cement in concrete and Waste Foundry Sand (WFS) as partial replacement to fine aggregate in concrete. Tests were performed for the assessment of water absorption, abrasion and various strength parameters of the paver blocks. Test results showed that there is significant strength that is achieved when a ternary blend concrete with substitution of 20% Fly Ash, 15% RHA as cementitious substitute material and 20% WFS as fine aggregate replacement material is used for the preparation of concrete paver blocks. These findings are essential to arrive at large scale utilization of industrial wastes in an ecofriendly manner and effective waste disposal strategies to establish a sustainable environment. The referred patent discusses the ecofriendly paver blocks using Fly ash and Rice husk ash to establish sustainable environment but does not provide any insight to the use of silica obtained from rice husk in tyre tread rubber composition.
Publication No. IN134/CHE/2003 & WO2004073600 relates to a novel process
for the manufacture of precipitated silica from rice husk ash, having a surface area ranging from 50-400m2/g and tap density of 80-600kg/m3 having multiple applications in the field of rubbers and plastics, paints, toothpastes, catalyst, carrier agent, insulation, stabilizing and desiccants. The process method for silica precipitation is novel, wherein the chemicals used are regenerated making it a
closed loop operation. The extraction process through digestion, precipitation and regeneration are done based on the application specifies, so as to get the required particle size and densities. The referred patent discusses about colloidal properties and manufacture of precipitated silica from rice husk ash having multiple applications in the field of rubbers and plastics, paints, toothpaste, catalyst, carrier agent, insulation, stabilizing and desiccant, but is silent on the use of silica obtained from rice husk in tyre tread rubber composition.
Publication No. IN202021056035 relates to method (100) for producing precipitated silica is disclosed. The rice husk ash is incinerated (102) at temperature of 900-1025oC to remove volatile substance and leached (104) with caustic soda flakes. The slurry is vacuum filtered (106) to separate leach cake and sodium silicate solution. The leach cake is washed (108) with water and dried in an oven at a temperature of about 110 to 120oC. The sodium sulphate solution is diluted and heated (110) with hot water and then sulphuric acid having a molarity in a range of 6 to 9M is added while maintaining (112) pH. The precipitated silica is filtered (114) to separate silica from sodium sulphate. Silica is washed and dried (116) to obtain precipitated silica having purity in a range of 98 to 99.6%. Sodium sulphate solution is evaporated and crystallized (118) to obtain sodium sulphate crystals. The referred patent discusses the zero-waste process while synthesizing silica from rice husk ash. Moreover, it discusses the method of manufacture of precipitated silica from rice husk ash and method of preparation of sodium sulphate crystals but does not provide any insights into silica obtained from rice husk for tire tread rubber composition.
Publication No. IN201721008780 relates to a process for preparing sodium silicate from rice husk ash a process for preparing sodium silicate from rice husk ash is disclosed. Said process comprises fusing the rice husk ash with trona at an elevated temperature ranging between 1200-1500 °c for a time period ranging between 2-4 hours to obtain sodium silicate. The referred patent discusses the manufacture of precipitated silica and a byproduct alkali metal silicate from rice husk ash with an alkali metal sulphate but does not provide any insights into silica obtained from rice husk for tire tread rubber composition.
Publication No. IN201721008778 relates to process for preparing water glass from rice husk ash a process for preparing water glass having na2o: sio2 ranging between 1:2.5- 1:3.7 is disclosed. Said process comprises treating rice husk ash with a caustic soda solution and water at a temperature ranging between 90 to 160°c under 2-3.5 bar pressure with stirring at 600-700 rpm for 1-3 hours, followed by separation of water glass from resultant reaction mixture. The referred patent discusses the preparation process of water glass from rice husk ash but does not provide any insights into silica obtained from rice husk for tire tread rubber composition.
Publication No. IN201721008751 relates to process for preparing silica from rice husk ash a process for preparing silica from rice husk ash is disclosed. Said process comprises fusing the rice husk ash with an alkali metal sulphate at an elevated temperature ranging between 1200 to 1500 °c for a time period ranging between 2-4 hours to obtain an alkali metal silicate; dissolving the obtained alkali metal silicate in an aqueous medium to obtain an alkali metal silicate solution and a first by-product comprising carbon dioxide and sulphur dioxide; acidifying the alkali metal silicate solution by addition of the first by-product, to cause precipitation of silica and release of a second by-product comprising said alkali metal sulphate. The referred patent discusses the manufacture of precipitated silica and a byproduct alkali metal silicate from rice husk ash with an alkali metal sulphate but fails to discuss anything with regard to silica obtained from rice husk as a reinforcing filler in tyre tread rubber composition.
Publication No. IN2441/DELNP/2010 relates to a sealant composition for the sealing of a punctured tyre including a liquid carrier, one or more viscosity and suspending agents, one or more fillers and sealants, and one or more polyacrylates. The referred patent discusses sealing rubber composition of punctured tyre but does not provide any insights into silica obtained from rice husk as a reinforcing filler in tyre tread rubber composition.
Publication No. IN/PCT/2001/00652/DEL provides a filler for use in composite materials wherein said filler comprises a vegetative-based material and wherein said vegetative-based material can be fresh or carbonized. In one particularly preferred embodiment the invention utilizes carbonized rice husk. In a further aspect of the invention there is provided a process for the production of a carbonized vegetative-based filler wherein said process comprises burning a fresh vegetative-based material at about 800 °C for about 4 seconds. The referred patent discusses the carbonized rice husk as a filler in composite materials but does not provide any insights into silica obtained from rice husk as a reinforcing filler in tyre tread rubber composition.
Publication No. JP2011068784 provides a rubber composition for tread which can improve on-ice performance and abrasion resistance, and to provide a studless tire using the same. solution: the rubber composition for tread includes a rubber component having a total content of natural rubber and butadiene rubber of 80 mass% or more, rice hull charcoal having an average particle size of 0.5-50 µm, and a silane coupling agent, wherein the content of rice husk carbide is 0.5-25 pts. mass based on 100 pts. mass of the rubber component, the content of silane coupling agent is 1-20 pts .mass based on the total content of 100 pts. mass of the rice hull charcoal and silica, the glass transition temperature is -50°c or less, and the hardness at 0°c is 64 or less. The referred patent discusses the rubber composition containing rice husk carbide for tyre tread to improve performance on ice and abrasion resistance but does not provide any insights into silica obtained from rice husk as a reinforcing filler in tyre tread rubber composition.
Publication No. KR20120028242 relates to a rice husk fiber and a rice husk fiber
paper using the same are provided to ensure relatively thickness of the paper due to air gap and to reduce drying energy during production process. Constitution: A rice husk paper of high bulk contains 1-50 wt% of rice husk fiber having cylindrical fiber and fiber of sawdust. The rice bran fiber is prepared by digesting rice husks or straw to separate digested liquid and residue, isolating silica from the isolated digested liquid; and obtaining fiber powder. The rice husk is treated with 150-200 g/m^3 of ozone after acetic acid treatment. The rice husk fiber has chemical composition containing 65-75% of carbon, 25-30% of oxygen, 0.1-0.5% of silicon, and 0.3-1% of calcium. The referred patent discusses the preparation of bulk rice hull fibre paper using rice bran fiber but does not provide any insights into silica obtained from rice husk as a reinforcing filler in tyre tread rubber composition.
Publication No. US6378584 provides a rubber composition for tire tread, which can provide a tire having low decrease in abrasion resistance and balanced performance of traction property, braking property and cornering property. The rubber composition for tire tread is obtained by mixing 100 parts by weight of at least one rubber component selected from the group consisting of a natural rubber, an isoprene rubber and a butadiene rubber, 5 to 45 parts by weight of a silica, 0.5 to 4.0 parts by weight of a silane coupling agent and 3 to 8 parts by weight of a powdered article containing cellulose material. The referred patent discusses the use of cellulose material rice husk with the sieve size 100 to 120 micrometer in tyre tread rubber composition for balanced performance of traction property, braking property and cornering property but does not provide any insights into silica obtained from rice husk as a reinforcing filler in tyre tread rubber composition.
Publication No. KR20020024612 relates to the tire rubber composition using rice
husk ashes and a green tire to reuse the rice husk for a tire for protecting the environment and improve the performance of the tire by the silica of high quality obtained from the rice husk ashes. Constitution: A tire rubber composition includes rubber as a raw material, an additive for a tire rubber composition, and rice husk ashes 5-50 phr as a reinforcement agent, wherein carbon black is used as further reinforcement agent, and the tire rubber composition prepared as above is applied to a tire tread. The referred patent discusses about the use of rice husk ash in tyre rubber composition but does not provide any insights into silica obtained from rice husk as a reinforcing filler in tyre tread rubber composition.
Publication No. MY176078 relates to an improved composition comprising sago activated carbon and rice husk ash derived from sago waste and rice husk, respectively, formed at a mixing ratio of 80:20 by weight that can be used in multiple applications such as an adsorbent, catalyst and soil amender. The said patent showcases excellent characteristics and performance during heavy metal adsorption, methylene blue dye removal and soil amendment or enhancement. Further the invention also can be used catalyst support in solid acid and base catalysts, which demonstrate excellent activities as heterogeneous catalysts. Mass production of biochar from the sago waste and the rice husk effectively reduces the problems of water, land and air pollution associated with the sago processing industries and rice mills. More particularly the said patent discusses the use of rice husk ash and sago activated carbon used as a catalyst for sago processing industries and rice mill which eliminates water, land and air pollution but does not discuss anything related to the rice husk-based silica for tyre tread rubber composition.
Publication No. EP2794287 relates to the tyre (1) for vehicle wheels, comprising a carcass structure (2), a belt structure (6) applied in a radially outer position to said carcass structure, a tread band (7) applied in a radially outer position to said belt structure (6), in which said tread band (7) comprises a crosslinked elastomeric composition comprising a finite number of particles of rice husk ash of coarse size. The referred patent discusses the use of rice husk ash in elastomeric composition but does not discuss anything related to rice husk-based silica in tyre tread rubber composition.
Publication No. AU2020104380 relates to the dry rice husk process and deep learning programming technology of extraction of high-quality pure silica. The dry rice husk is placed in the defined volume hermetically sealed can, add respectively then red , green fuming nitric acid and concentration be 29% to 33% hydrogen peroxide in rice husk other composition also add h 20+ 02: h 20 2(by weight) be 1: 46 or 1: 50 or rice husk: h 20 2 be 2: 4 or 1: 5, h 20 2: h2 0 + no 2 +02: hno 3(volume ratio) is 11 :2 or 10 : 1, h 20 2with the hermetically sealed can volumetric ratio be 1.3 : 4.10 or 1: 6, tighten sealed tank cap, in 147 0c to 151 °c of lower insulations 2 to 3 hours; naturally be chilled to room temperature, open sealed tank cap, to neutral, can obtain purity and be the silica approx. 99.99% with deionized water rinsing. This method is easy and simple to handle, and extraction rate is fast, and raw material sources are abundant, low production cost. The invented technology also includes a extract the method for silicon-dioxide in the dry rice husk, on the books in the document, for example, mention among the de2416291, dry rice husk can be made crystalline silica for building at 201-455 °c 450-550 °c 700-805 °c through three burnings respectively. The invented technology also includes writing among the cn86104705, husk or straw are put into the kiln roasting, clean then, can obtain the amorphous silica that content is 92-99%. Report among the cn86107192, rice husk is placed in the roaster heats up through slow, low-temperature bake can obtain content and reach 98.56% silica. The referred publication discusses the manufacturing method of rice husk-based silica but does not discuss anything related to rice husk-based silica in tyre tread rubber composition.
Reference made to an article entitled “Rice husk silica as a sustainable filler in the tire industry” which discusses comparing rice husk silica (RHS) with conventional precipitated silica, which has nearly the same surface area, and replaced part of the carbon black with RHS and conventional silica in a basic tread formulation. All formulations were mixed with the same amount of filler during the study. Silica was used at 15, 30 and 50 phr loading, and part of the carbon black was replaced by silica. Compound curing characteristics, physical properties, rebound resilience, heat generation, abrasion loss, dynamic properties and morphology were analyzed.
The results indicated that RHS demonstrated compound properties comparable to those of conventional silica. As part of the carbon black was replaced with conventional silica, a slower cure rate, higher rebound resilience, lower heat generation, lower abrasion loss, and lower tan delta were observed with no significant change in physical properties, but some changes in physical properties were observed using one way ANOVA analysis. We found the same trend when replacing part of the carbon black with RHS, such as a slower cure rate, higher rebound resilience, lower heat generation, lower abrasion loss, and lower tan delta with no significant change in physical properties, but some changes in physical properties were observed using one-way ANOVA. This sustainable material could be used to replace conventional silica in tire compounding, as well as to replace a portion of carbon black with RHS for improved heat build-up, rolling resistance, and abrasion loss. The referred publication discusses the manufacturing method of rice husk-based silica in natural rubber based rubber composition but does not relate to rice husk-based silica in SSBR: PBR or SSBR: NdBR blend based tyre tread rubber composition for high performance tyres.
Reference made to an article entitled “Rice husk ash as filler in tread compounds to improve rolling resistance talks about use of rice husk ash in tyre tread rubber composition to improve low rolling resistance. The referred article discusses the use of rice husk ash in tyre tread rubber composition but does not discuss anything related to rice husk-based silica in tyre tread rubber composition.
Thus, the conventional process of manufacturing silica by sand fusion is highly energy intensive as the process requires the reactants to be heated to high temperatures around 1400°C. Also, the conventional process and other processes using sodium silicate obtained from rice husk ash involves acid (i.e., sulphuric acid) precipitation of the sodium silicate to produce Precipitated Silica. Sodium sulphate is a waste that is generated and this liquid effluent requires elaborate treatment to meet emission standards. The process requires effluent treatment plant for treating sodium sulphate. This calls for additional financial implications and any carelessness in treating the effluent would damage the environment. Hence there needed an improved method of obtaining silica from rice husk which could be used for tire composition.
In order to overcome above-listed prior art, the present invention aims to provide tire tread rubber composition using silica obtained from rice husk as a renewable reinforcing filler and its method of preparation.
SUMMARY OF THE INVENTION:
In one aspect of the present invention a tire tread rubber composition is provided.
The tire tread rubber composition comprising: Elastomeric matrix of 100 (parts per hundred rubber) phr; reinforcing filler ranging from 1-20 phr ; renewable reinforcing filler comprising rice husk-based silica ranging from of 1-80 (Phr) to enhance the reinforcing properties; wherein the rice husk-based silica has a specific surface area ranging from 125 to 210 m²/gm; coupling agent ranging from 0.8-8 phr; vulcanization agent comprising sulphur in the range of 1-3 phr; primary accelerator ranging from 1-3 phr; secondary accelerator ranging from 1-3 phr; process oil ranging from 5-10 phr, wherein the process oil is selected from TDAE oil, MES oil, or vegetable oils; hydrocarbon resin in the ranging from 3-7 phr, wherein the hydrocarbon resin is selected from C5, C5/C9 type, or a naturally occurring resin or a combination thereof and Anti-degradant ranging from 1-4 phr.
In some aspects of the present invention, the elastomeric matrix comprises a blend of Solution Styrene Butadiene Rubber (SSBR) ranging from 70-84 phr and/or Butadiene Rubber (BR) ranging from 16 -30 phr or Solution Styrene Butadiene Rubber (SSBR) ranging from 70-84 phr and/or Neodymium Butadiene Rubber (Nd BR) ranging from 16 -30 phr, wherein the SSBR comprises 27% to 29% bound styrene content and 56% to 60% vinyl content.
In some aspects of the present invention, the reinforcing filler comprises carbon black grades selected from HAF, ISAF, SAF types, or a blend thereof.
In some aspects of the present invention, Zinc oxide in the range of 2.0-3.5 Phr, Stearic acid in the range of 1-3 Phr, and Microcrystalline wax (MC Wax) in the range of 1-3 Phr.
In some aspects of the present invention, the primary accelerator is selected from a group consisting of N-cyclohexyl-2-benzothiazolesulfenamide(CBS), N-tert-butyl-2-benzothiazole sulfenamide (TBBS), 2-2'-Dithiobis(benzothiazole) (MBTS), or a combination thereof; and the secondary accelerator comprises diphenylguanidine (DPG), also the coupling agent is selected from Si 69, Si 75, or X50S.
In some aspects of the present invention the anti-degradant includes 6PPD, DTPD, TMQ, SP, OCD or its combination thereof.
In a second aspect of the present invention a method for preparing a tire tread rubber composition is provided.
The method for preparing a tire tread rubber composition comprising the steps of:
Step I: Preparing a first master batch in a Banbury mixer comprising:
Charging the mixing chamber with elastomers and mixing for a duration of 10 to 40 seconds;
Adding a reinforcing filler comprising 100% carbon black and 100% rice husk-based silica along with a coupling agent, and mixing for 100 to 200 seconds;
Performing silanisation by reducing the rotor speed to 20 to 30 rpm at a temperature of approximately 135°C to 140°C for 20 to 30 seconds;
Adding MC wax, stearic acid, process oil, hydrocarbon resin and mixing for 50 to 60 seconds;
Sweeping down in the orifice and mixing for 50 to 60 seconds, and dumping the compound at a temperature in the range of 150°C to 165°C;
Sheeting out the rubber compound in laboratory two-roll mill;
Step II: Preparing a second master batch by:
Charging the Banbury mixer with the first master batch from Step I, adding zinc oxide and 6PPD, and mixing for 120 to 130 seconds;
Dumping the batch at a temperature range of 130°C to 140°C;
Step III: Preparing a third master batch by:
Charging the Banbury mixer with the second batch of Step II, mixing for 100 to 130 seconds, and dumping the batch at a temperature range of 120°C to 140°C and sheeting out in the laboratory two roll mill;
Step IV: Preparing a final batch by:
Charging the Banbury mixer with the third master batch of Step III adding curatives including sulfur, CBS, and DPG, and mixing for 50 to 80 seconds;
Dumping the final batch at a temperature range of 90°C to 110°C;
Sheeting out the final rubber compound on a laboratory two-roll mill.
In some aspects of the present invention, the method for preparing a tire tread rubber composition involves the rice husk-based silica which is obtained from rice husks with a specific surface area ranging from 165 to 185 m2/gm.
In some aspects of the present invention, the method for preparing a tire tread rubber composition involves a blend of elastomers reinforced with carbon black and a renewable reinforcing filler comprising rice husk-based silica, thereby exhibiting improved abrasion resistance and enhanced rubber elasticity.
In some aspects of the present invention, the method for preparing a tire tread rubber composition wherein the rubber vulcanizate's dynamic properties are evaluated using a dynamic mechanical analyzer, demonstrating improved winter traction, ice grip, wet grip and LRR Property.
OBJECTS OF THE INVENTION:
The principal object of the present invention is to provide tire tread rubber composition using silica obtained from rice husk as a renewable reinforcing filler and its method of preparation.
Another object of the present invention is to provide rice husk-based silica as a renewable reinforcing filler in green tyre rubber composition .
Yet another object of the invention is to provide rice husk-based silica as a renewable reinforcing filler in high performance tyre tread rubber composition.
Yet another object of the present invention is to replace or eliminate conventional reinforcing filler silica.
Yet another object of the present invention is to use renewable reinforcing filler rice husk-based silica is added along with reinforcing filler carbon black or partially replace with reinforcing filler carbon black.
Yet another object of the present invention is to provide cost effective and environment friendly tyre. 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.
BREIF DESCRIPTION OF THE INVENTION:
The present invention relates to the tire tread composition and its method of preparation. The present invention discusses the use of silica obtained from rice husk as a renewable reinforcing filler in tyre rubber composition. The invention provides rice husk-based silica as a renewable reinforcing filler in green tire tread rubber composition and its method thereof. The rice husk-based silica with the specific surface area ranges from 165 to 185 m2/gm improves the dynamic mechanical properties of tyre treads.
The rice husk-based silica is used as a renewable reinforcing filler in SSBR: Nd BR blend or SBBR: PBR di-blend based tire tread rubber composition to improve the dynamical mechanical properties. The rubber composition for tire treads comprises elastomeric matrix; rice husk-based silica as a renewable reinforcing filler; reinforcing filler carbon black; coupling agent; activators; anti-degradants; vulcanization agent; primary accelerators.
In one aspect of the present invention a tire tread rubber composition is provided.
The tire tread rubber composition comprising: Elastomeric matrix of 100 (parts per hundred rubber) phr; reinforcing filler ranging from 1-20 phr ; renewable reinforcing filler comprising rice husk-based silica ranging from of 1-80 (Phr) to enhance the reinforcing properties;wherein the rice husk-based silica has a specific surface area ranging from 125 to 210 m²/gm; coupling agent ranging from 0.8-8 phr; vulcanization agent comprising sulphur in the range of 1-3 phr; primary accelerator ranging from 1-3 phr; secondary accelerator ranging from 1-3 phr; process oil ranging from 5-10 phr, wherein the process oil is selected from TDAE oil, MES oil, or vegetable oils; hydrocarbon resin in the ranging from 3-7 phr, wherein the hydrocarbon resin is selected from C5, C5/C9 type, or a naturally occurring resin or a combination thereof and Anti-degradant ranging from 1-4 phr.
In some aspects of the present invention, the elastomeric matrix comprises a blend of Solution Styrene Butadiene Rubber (SSBR) ranging from 70-84 phr and/or Butadiene Rubber (BR) ranging from 16 -30 phr or Solution Styrene Butadiene Rubber (SSBR) ranging from 70-84 phr and/or Neodymium Butadiene Rubber (Nd BR) ranging from 16 -30 phr, wherein the SSBR comprises 27% to 29% bound styrene content and 56% to 60% vinyl content.
In some aspects of the present invention, the reinforcing filler comprises carbon black grades selected from HAF, ISAF, SAF types, or a blend thereof.
In some aspects of the present invention, Zinc oxide in the range of 2.0-3.5 Phr, Stearic acid in the range of 1-3 Phr, and Microcrystalline wax (MC Wax) in the range of 1-3 Phr.
In some aspects of the present invention, the primary accelerator is selected from a group consisting of N-cyclohexyl-2-benzothiazolesulfenamide(CBS), N-tert-butyl-2-benzothiazole sulfenamide (TBBS), 2-2'-Dithiobis(benzothiazole) (MBTS), or a combination thereof; and the secondary accelerator comprises diphenylguanidine (DPG), also the coupling agent is selected from Si 69, Si 75, or X50S.
In some aspects of the present invention the anti-degradant from 6PPD, DTPD, TMQ, SP, OCD or its combination thereof.
Rubber composition in Phr:

Ingredients Control, C1 Formulation related to Invention, F1
SSBR 77.0 77.0
NdBR 23.0 23.0
Carbon Black N234 15.0 15.0
Precipitated Silica 60.0
Rice husk-based Silica, Renewable Reinforcing filler (Green Silica)

40.0
Si 75 6.0 4.0
Zinc oxide 2.3 2.3
Stearic acid 1.2 1.2
6PPD 1.8 1.8
MC wax 1.2 1.2
TDAE Oil 8.0 8.0
Hydrocarbon resin, Impera Resin 1507 5.0 5.0
CBS 1.8 1.8
DPG 1.0 1.0
Sulphur 2.2 2.2

1. SSBR – It is non-oil extended styrene butadiene rubber (solution polymerized) with 27 to 29% of bound styrene content and 56 to 60% of vinyl content with a Tg of -26 Deg C from Kumho Petrochemical. The polymer selected for the present invention is affinity towards reinforcing filler SiO2 Content.
2. Nd BR – It is ultra-high cis polybutadiene rubber, produced by 1, 3-butadiene polymerization with a novel neodymium catalyst having more than 97% of 1, 4 cis content and it is from Kumho Petro chemical, Korea.
3. Carbon Black, N234 -It is the reinforcing filler ISAF, Intermediate Superior Abrasion Furnace having the Iodine adsorption No. 119 to 126 mg/gm, tinting strength value between 118 to 128 % ITRB, nitrogen surface area value between 114 to 124 m2/gm and COAN value ranges between 97 to 107 cc/100 gm. It is from Himadri Speciality chemical Ltd, India.
4. 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.
5. Rice husk-based Silica – It is obtained from the rice husk i.e., rice husk is burnt in boiler and the rice husk ash is collected and processed into silica which is renewable reinforcing filler and also it can be called as precipitated silica green silica 175 GR. It is having specific surface area ranging from 165 to 185 m2/gm and its SiO2 content is greater than 98%. It is from Energec Chem Specialities Pvt Ltd, 25/1 Avadi Poonamallee High Road, Seneerkuppam, Chennai 600056, Tamilnadu, India,
6. Coupling agent - Si75 is a bifunctional, sulfur containing organosilane from Nanjing Shuguang Silane Chemical Co Ltd, China.
7. 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.
8. 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.
9. 6PPD- (N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine) from Nocil Limited, India. It is added to the rubber composition to provide resistance to thermooxidative ageing of elastomers.
10. MC Wax - Microcrystalline wax from GPL, India. It is used in rubber compounds to provide ozone resistance.
11. Process Oil – It is TDAE oil from Panoma Petroleum, India and it is treated distillate aromatic extracts (TDAE) is a rubber processing oil and it enhances rubber processing and acting as a plasticizer and reduces viscosity of the rubber compound.
12. Impera Resin P1507 – It is a hydrocarbon resin having a softening point 101 Deg C and its glass transition temperature is 47 Deg C. It is from Eastman Chemical Switzerland LLC, USA. It helps in improving the performance of tyre and it improves the tackiness of rubber compound.
13. CBS- (N-cyclohexyl-2-benzothiazolesulfenamide) - It is a delayed action accelerator suitable for diene rubbers from Nocil Limited, India.
14. DPG- Diphenylguanidine It is secondary accelerator, used to activate the primary accelerator) from PMC Rubber Chemicals India Pvt ltd, India.
15. Sulphur is the vulcanizing agent from The Standard Chemical Co. Pvt Ltd, India.
The method of preparation of the rubber composition includes the following:
An embodiment of the present invention discloses a method of preparation of a rubber composition for tyre tread with diene-based rubber blend comprising solution styrene butadiene rubber and Neodymium butadiene rubber; a reinforcing filler comprising of carbon black and renewable reinforcing filler rice husk-based silica; and hydrocarbon resin as a processing aid.
The steps comprise of: -
Rubber composition is prepared by a thermomechanical process. To demonstrate the process is carried out using a Banbury mixer.
A) Method of preparation of master batch comprising of the steps:
Step 1: Preparation of master batch has been performed with the rotation speed of the mixer between 45 to 70 rpm and with the head temperature of the Banbury maintained between 80 to 95°C.
i) mixing chamber has been charged with the elastomers, and allowed to mix for 10 to 40 seconds,
ii) Addition of 100% of the reinforcing filler carbon black and 100 % of the rice husk-based renewable reinforcing filler silica, coupling agent and allowed to mix for 100 to 200 seconds,
iii) The process of silanisation has been done with the reduced rotor speed 20 to 30 rpm at around 135 to 140°C for 20-30 seconds,
iv) The remaining rubber chemicals namely MC wax, stearic acid, process oil, hydrocarbon resin are added and allowed to mix for 50 to 60 seconds,
v) sweeping down in the orifice and allowed to mix for 50 to 60 seconds and the compound has been dumped at the temperature in the range of 150°C to 165°C. The rubber compound has been sheeted out in the laboratory two-roll mill.
Step II: Mixing chamber of the Banbury charged with the Step I master batch, chemicals zinc oxide and 6PPD (N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine), and allowed to mix for 120 to 130 seconds and dumped in the temperature range of 130°C to 140°C. The rubber compound has been sheeted out in the laboratory two-roll mill.
Step III:
Mixing chamber of the Banbury charged with the Step II master batch, and allowed to mix for 100 to 130 seconds and dumped at the temperature range of 120°C to 140°C. The rubber compound has been sheeted out in the laboratory two-roll mill.
Step IV:
Method of preparation of final batch comprising of the steps:
Mixing chamber charged with the Step III master batch and the curatives Sulphur, CBS (N-cyclohexyl-2-benzothiazolesulfenamide) and DPG (Diphenylguanidine) are added, and allowed to mix for 50 to 80 seconds and dumped at the temperature range of 90°C to 110°C. Final batch rubber compound sheet out has been done in the laboratory mill.
In some aspects of the present invention, the method for preparing a tire tread rubber composition involves the rice husk-based silica which is obtained from rice husks with a specific surface area ranging from 165 to 185 m2/gm.
In some aspects of the present invention, the method for preparing a tire tread rubber composition involves a blend of elastomers reinforced with carbon black and a renewable reinforcing filler comprising rice husk-based silica, thereby exhibiting improved abrasion resistance and enhanced rubber elasticity.
In some aspects of the present invention, the method for preparing a tire tread rubber composition wherein the rubber vulcanizate's dynamic properties are evaluated using a dynamic mechanical analyzer, demonstrating improved winter traction, ice grip, wet grip and LRR Property.

Analysis of the properties of the rubber compound:
M1. 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, t5 indicates the time to scorch (MV+5) which indicates the processing properties (process safety).
M2. Shore A Hardness:
Shore A Hardness of the Rubber Vulcanizates are assessed in accordance with ASTM D 2240 in Shore A Durometer
M3. 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 -10 Deg C is commonly used as a predictor for Ice traction. Higher the tan delta value at 10 Deg C, better the Ice grip/Ice 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.
M4. 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. Higher the Rebound Resilience % indicates the High Rubber Elasticity of Rubber Vulcanizate.
M5. Abrasion Loss of the Rubber Vulcanizate
Abrasion Loss of the Rubber Vulcanizate is measured in DIN Abrader in accordance with ASTM D 5963.
The compound properties are listed in Table 2 below-
Table 2: Characterization of Uncured Rubber Compound and Cured Rubber Vulcanizate
Properties Control, C1 F2, Formulation related to invention Index
M1. Mooney Scorch Properties of Final Batch Rubber Compound
Mooney Scorch, T5 @ 125 Deg C, (Ideal value is greater than 18 minutes) 29.12 26.92 -
M2. Hardness of Rubber Vulcanizate
Hardness, Shore A 73 67 -
M3. Dynamic Properties of Rubber Vulcanizate
Winter traction, E’@
-20 Deg C (Mpa), Lower the index value is better 239.68
122.53
51.12
(48.88% improvement)
Ice Traction, tan delta at -10 Deg C (Higher the index value is better) 0.629 0.768 122.10
Wet traction, tan delta at 0°C
(Higher the index value is better) 0.483
0.521
107.66
Rolling resistance, tan delta 60 Deg C (Lower the index value is better) 0.114
0.079 69.91
(30.09% improvement)
M4. Rebound Resilience of Rubber Vulcanizate
Rebound Resilience, % at
23 +/-2 Deg C 41.65 48.92 117.45
M5. Wear Resistance of Rubber Vulcanizate
Din Abrasion Loss, mg (Ideal value of Abrasion Loss for LRR along with Grip tread compound is lesser than 170 mg) 93.02 95.88 -

The purpose of these tests is to measure the rubber compound properties of the compositions related to invention, F1 against the control composition, C1. Rubber composition based on SSBR: Nd BR blend-based formulation, reinforced by carbon black containing 40 phr of renewable reinforcing filler rice husk-based silica against SSBR: NdBR based formulation reinforced by carbon black containing 60 phr of precipitated silica (Control, C1) are prepared and evaluated.
Also, the present invention provides a 100 parts by weight of rubber composition F1, SSBR: Nd BR blend-based rubber composition containing reinforced by carbon black containing 40 phr of renewable reinforcing filler rice husk-based silica gave t5 value as 26.92 when compared to SSBR: NdBR blend based rubber composition reinforced by carbon black and 60 phr of precipitated silica, C1 (Control). Note: t5 value greater than 18 minutes provides better processing characteristics of rubber compound.
Also, the present invention provides a 100 parts by weight of rubber composition F1, SSBR: Nd BR blend-based rubber composition containing reinforced by carbon black containing 40 phr of renewable reinforcing filler rice husk-based silica gave hardness value 67 Shore A.
Also, the present invention provides a 100 parts by weight of rubber composition F1, SSBR: Nd BR blend-based rubber composition containing reinforced by carbon black containing 40 phr of renewable reinforcing filler rice husk-based silica gave E’ at -20 Deg C as 122.53 Mpa i.e., 48.88% improvement which clearly states the effect of renewable reinforcing filler rice based silica when compared to SSBR: NdBR blend based rubber composition reinforced by carbon black and 60 phr of precipitated silica, C1 (Control).
Further, the present invention provides a 100 parts by weight of rubber composition F1, SSBR: Nd BR blend-based rubber composition containing reinforced by carbon black containing 40 phr of renewable reinforcing filler rice husk-based silica gave tan delta at -10 Deg C as 0.768 (No unit) i.e., 22.10% improvement which clearly states the effect of renewable reinforcing filler rice based silica on ice grip when compared to SSBR: NdBR blend based rubber composition reinforced by carbon black and 60 phr of precipitated silica, C1 (Control).
Further, the present invention provides a 100 parts by weight of rubber composition F1, SSBR: Nd BR blend-based rubber composition containing reinforced by carbon black containing 40 phr of renewable reinforcing filler rice husk-based silica gave tan delta at 0 Deg C as 0.521 (No unit) i.e., 7.66% improvement which clearly states the effect of renewable reinforcing filler rice based silica on wet grip when compared to SSBR: NdBR blend based rubber composition reinforced by carbon black and 60 phr of precipitated silica, C1 (Control).
Moreover, the present invention provides a 100 parts by weight of rubber composition F1, SSBR: Nd BR blend-based rubber composition containing reinforced by carbon black containing 40 phr of renewable reinforcing filler rice husk-based silica gave tan delta at 60 Deg C as 0.079 (No unit) i.e., 30.09% improvement which clearly states the effect of renewable reinforcing filler rice based silica on wet grip when compared to SSBR: NdBR blend based rubber composition reinforced by carbon black and 60 phr of precipitated silica, C1 (Control).
Also, the present invention provides a 100 parts by weight of rubber composition F1, SSBR: Nd BR blend-based rubber composition containing reinforced by carbon black containing 40 phr of renewable reinforcing filler rice husk-based silica gave rebound resilience % as 48.92 % i.e., 17.45% improvement which clearly states the effect of renewable reinforcing filler rice based silica on rubber elasticity when compared to SSBR: NdBR blend based rubber composition reinforced by carbon black and 60 phr of precipitated silica, C1 (Control).
Further, the present invention provides a 100 parts by weight of rubber composition F1, SSBR: Nd BR blend-based rubber composition containing reinforced by carbon black containing 40 phr of renewable reinforcing filler rice husk-based silica gave abrasion loss as 95.88 mg which clearly states the effect of renewable reinforcing filler rice based silica on rubber elasticity when compared to SSBR: NdBR blend based rubber composition reinforced by carbon black and 60 phr of precipitated silica, C1 (Control).
Moreover, the present invention also helps in tread compound weight reduction along with better performance i.e., lesser usage (33.33%) of renewable reinforcing filler silica in place of precipitated silica which implies lower tyre weight.
Hence, the present invention provides 100 parts by weight of rubber composition, SSBR: NdBR blend based rubber composition reinforced by carbon black containing 40 phr of renewable reinforcing filler rice husk-based silica provides better winter traction, ice grip, wet grip along with lower rolling resistance property. Also, the present invention provides higher rubber elasticity and optimum wear resistance when compared to SSBR: NdBR blend based rubber composition reinforced by carbon black containing 60 phr of reinforcing filler precipitated Silica.
Advantages:
a) Rice husk-based silica used as a renewable reinforcing filler in high performance tyre tread rubber composition is obtained from renewable resources.
b) Rice husk-based silica (green silica) is used as a renewable in tyre tread rubber composition for high performance tyre tread motorcycle or scooter tyres.
c) Rice husk-based silica (green silica) is used as a renewable reinforcing filler in tyre tread rubber composition providing better winter traction and ice grip.
d) Rice husk-based silica (green silica) is used as a renewable reinforcing filler in tyre tread rubber composition which provides better wet grip and lower rolling resistance.
e) Rice husk-based silica (green silica) is used as a renewable reinforcing filler in tyre tread rubber composition which provides better processing properties, high rubber elasticity and optimized wear resistance.
f) Partial replacement or elimination of conventional precipitated silica by using rice husk-based silica reduces carbon footprint.
g) Cost effective.
,CLAIMS:We claim:
1. A tire tread rubber composition comprising:
Elastomeric matrix of 100 (parts per hundred rubber) phr;
Reinforcing filler ranging from 1-20 phr ;
Renewable reinforcing filler comprising rice husk-based silica ranging from of 1-80 (Phr) to enhance the reinforcing properties;
wherein the rice husk-based silica has a specific surface area ranging from 125 to 210 m²/gm;
Coupling agent ranging from 0.8-8 phr;
Vulcanization agent comprising sulphur in the range of 1-3 phr;
Primary accelerator ranging from 1-3 phr;
Secondary accelerator ranging from 1-3 phr;
Process oil ranging from 5-10 phr, wherein the process oil is selected from TDAE oil, MES oil, or vegetable oils;
Hydrocarbon resin in the ranging from 3-7 phr, wherein the hydrocarbon resin is selected from C5, C5/C9 type, or a naturally occurring resin or a combination thereof;
Anti-degradant ranging from 1-4 phr.
2. The tire tread rubber composition as claimed in claim 1, wherein the elastomeric matrix comprises a blend of Solution Styrene Butadiene Rubber (SSBR) ranging from 70-84 phr and/or Butadiene Rubber (BR) ranging from 16 -30 phr or Solution Styrene Butadiene Rubber (SSBR) ranging from 70-84 phr and/or Neodymium Butadiene Rubber (Nd BR) ranging from 16 -30 phr ;
wherein the SSBR comprises 27% to 29% bound styrene content and 56% to 60% vinyl content.
3. The tire tread rubber composition as claimed in claim 1, wherein the reinforcing filler comprises carbon black grades selected from HAF, ISAF, SAF types, or a blend thereof.
4. The tire tread rubber composition as claimed in claim 1, further comprising Zinc oxide in the range of 2.0-3.5 Phr, Stearic acid in the range of 1-3 Phr, and Microcrystalline wax (MC Wax) in the range of 1-3 Phr.
5. The tire tread rubber composition as claimed in claim 1, wherein the primary accelerator is selected from a group consisting of N-cyclohexyl-2-benzothiazolesulfenamide(CBS), N-tert-butyl-2-benzothiazole sulfenamide (TBBS), 2-2'-Dithiobis(benzothiazole) (MBTS), or a combination thereof; and the secondary accelerator comprises diphenylguanidine (DPG).
6. The tire tread rubber composition as claimed in claim 1, wherein the coupling agent is selected from Si 69, Si 75, or X50S.
7. The tire tread rubber composition as claimed in claim 1, wherein the anti-degradant from 6PPD, DTPD, TMQ, SP, OCD or its combination thereof.
8. A method for preparing a tire tread rubber composition comprising the steps of:
i. Step I: Preparing a first master batch in a Banbury mixer comprising:
Charging the mixing chamber with elastomers and mixing for a duration of 10 to 40 seconds;
Adding a reinforcing filler comprising 100% carbon black and 100% rice husk-based silica along with a coupling agent, and mixing for 100 to 200 seconds;
Performing silanisation by reducing the rotor speed to 20 to 30 rpm at a temperature of approximately 135°C to 140°C for 20 to 30 seconds;
Adding MC wax, stearic acid, process oil, hydrocarbon resin and mixing for 50 to 60 seconds;
Sweeping down in the orifice and mixing for 50 to 60 seconds, and dumping the compound at a temperature in the range of 150°C to 165°C;
Sheeting out the rubber compound in laboratory two-roll mill;
ii. Step II: Preparing a second master batch by:
Charging the Banbury mixer with the first master batch from Step I, adding zinc oxide and 6PPD, and mixing for 120 to 130 seconds;
Dumping the batch at a temperature range of 130°C to 140°C;
iii. Step III: Preparing a third master batch by:
Charging the Banbury mixer with the second batch of Step II, mixing for 100 to 130 seconds, and dumping the batch at a temperature range of 120°C to 140°C and sheeting out in the laboratory two roll mill;
iv. Step IV: Preparing a final batch by:
Charging the Banbury mixer with the third master batch of Step III adding curatives including sulfur, CBS, and DPG, and mixing for 50 to 80 seconds;
Dumping the final batch at a temperature range of 90°C to 110°C;
Sheeting out the final rubber compound on a laboratory two-roll mill.
9. The method for preparing a tire tread rubber composition as claimed in claim 8, the rice husk-based silica is obtained from rice husks with a specific surface area ranging from 165 to 185 m2/gm.
10. The method for preparing a tire tread rubber composition as claimed in claim 8, wherein the composition comprises a blend of elastomers reinforced with carbon black and a renewable reinforcing filler comprising rice husk-based silica, thereby exhibiting improved abrasion resistance and enhanced rubber elasticity.
11. The method for preparing a tire tread rubber composition as claimed in claim 8, wherein the rubber vulcanizate's dynamic properties are evaluated using a dynamic mechanical analyzer, demonstrating improved winter traction, ice grip, wet grip and LRR Property.