FIELD OF INVENTION

[0001] The subject matter described herein relates to the field of rubber and in particularly relates to a process for mixing rubber components.

BACKGROUND OF THE INVENTION

[0002] Production of rubber and rubber products is inevitably a large and diverse industry. Rubbers are processed using various processes which involves variety of additives and the processing techniques. The method of processing the rubber defines the nature and the quality of the rubber product. Conventionally the process of mixing involves a higher temperature at various stages which eventually affects the various properties of the rubber. Further there is an increase in the final temperature of the rubber which makes the processing of the rubber difficult. Along with the higher temperatures, the known processing methods includes higher power and energy which results in the undesirable properties of the rubber. Also scorch safety is affected largely due to processing at higher temperatures. Hence there has been various research carried out to identify an efficient process for the processing of rubber components.

[0003] US6884835B2 discloses a process for making a vulcanized rubber article comprising kneading at a temperature within the range of about 70°C to about 190°C in a bulk thermomechanical mixer. CN 106947122A discloses a preparation method of rubber composition in banbury mixer at temperatures in the range of 130°C to 165 °C. [0004] Although wide range of attempts have been made to obtain process for mixing rubber components, there is still a dire need in the state of art for a simple, efficient, and energy saving process of mixing/processing the rubber components to obtain a desirable rubber compound. SUMMARY OF THE INVENTION

[0005] In an aspect of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a) mixing at least one polymer, a peptizer, a soft carbon black and at least one first additive sequentially in an internal mixer to obtain a first mixture; b) contacting the first mixture with a cold oil to obtain a second mixture; and c) kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C.

[0006] In another aspect of the present disclosure, there is provided rubber compound obtained by the process comprising: a) mixing at least one polymer, a peptizer, a soft carbon black and at least one first additive sequentially in an internal mixer to obtain a first mixture; b) contacting the first mixture with a cold oil to obtain a second mixture; and c) kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C.

[0007] In one another aspect of the present disclosure, there is provided an article comprising the final rubber mixture obtained by the process comprising: a) mixing at least one polymer, a peptizer, a soft carbon black and at least one first additive sequentially in an internal mixer to obtain a first mixture; b) contacting the first mixture with a cold oil to obtain a second mixture; and c) kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C, wherein the article is an automotive tire, conveyer belts, belts, treads, sidewalls of tires or other parts of tire.

[0008] These and other features, aspects, and advantages of the present subject matter will be better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

DETAILED DESCRIPTION OF THE INVENTION

[0009] Those skilled in the art will be aware that the present disclosure is subject to variations and modifications other than those specifically described. It is to be understood that the present disclosure includes all such variations and modifications. The disclosure also includes all such steps, features, compositions, and compounds referred to or indicated in this specification, individually or collectively, and any and all combinations of any or more of such steps or features.

Definitions

[0010] For convenience, before further description of the present disclosure, certain terms employed in the specification, and examples are delineated here. These definitions should be read in the light of the remainder of the disclosure and understood as by a person of skill in the art. The terms used herein have the meanings recognized and known to those of skill in the art, however, for convenience and completeness, particular terms and their meanings are set forth below.

[0011] The articles "a", "an" and "the" are used to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article.

[0012] The terms "comprise" and "comprising" are used in the inclusive, open sense, meaning that additional elements may be included. It is not intended to be construed as "consists of only".

[0013] Throughout this specification, unless the context requires otherwise the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated element or step or group of element or steps but not the exclusion of any other element or step or group of element or steps.

[0014] The term "including" is used to mean "including but not limited to". "Including" and "including but not limited to" are used interchangeably. [0015] Ratios, concentrations, amounts, and other numerical data may be presented herein in a range format. It is to be understood that such range format is used merely for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a temperature in the range of about 110 to 120 °C should be interpreted to include not only the explicitly recited limits of about 110 °C to about 120 °C but also to include sub-ranges, such as 110-119 °C, 111-115 °C and so forth, as well as individual amounts, including fractional amounts, within the specified ranges, such as 110.2 °C, 112 °C, and 118 °C for example.

[0016] The term "at least one" is used to mean one or more and thus includes individual components as well as mixtures/combinations.

[0017] For the purposes of the present disclosure, the term "phr" refers to parts per hundred rubber, and it is a unit well used in the field of rubber technology to define the amount of ingredients used.

[0018] The term “rpm” refers to rotations per minute which refers to number of rotations in one minute. The term “rpm” refers to the stirring speed of the mixture of rubber components to ensure complete mixing of all components.

[0019] The term “peptizer” refers to a material added in rubber compounding to prevent the coagulation of a colloid suspension; specifically acts as a catalyst to facilitate the process of mastication or vulcanization of rubber, by preventing the recombination of broken polymer chains. In the present disclosure, peptizer can be either physical peptizer or a chemical peptizer. Peptizers may be selected from, but are not limited to organo sulphur compounds, aromatic disulfide compounds, aromatic mercaptan compounds, halogenated pyridine, a halogenated pyrimidine, halogenated diazine, halogenated triazine, an aromatic halogenated thiol, diphenyl disulfide. [0020] The term “dump temperature” refers to temperature at which the rubber mixture is discharged from the internal mixture and is loaded into the processor or mill for further processing. The lower the dump temperature higher will be the process safety. In the present disclosure, the dump temperature refers to the temperature of the final rubber mixture after mixing all the rubber components.

[0021] The term “M 100%” and “M 300 %” refers to the force at a specific elongation value, i.e. 100% or 300% elongation and is expressed in pounds per square inch (psi) or mega pascal (MPa).

[0022] The term “tensile strength” refers to as the amount of force in pounds per square inch (psi) or megapascals (MPa) required to pull a specimen to the point of material failure.

[0023] The term “elongation at break” refers to the force which is measured by stretching the material up to its rupture and determining the change in length from original.

[0024] The term “hardness” refers to the measure of the resistance a material has to indentation.

[0025] The term “ML” is the minimum torque (ML) refers to a measure of the extent of mastication. The term “MH” the maximum torque (MH) refers to an indication of the cross-linking density of the fully vulcanized rubber.

[0026] The terms TC10 refers to the time taken for rubber curing TC 10 refers to the time taken to vulcanize/cure 10% of the rubber. Similarly TC30, TC50, TC90 refer to the time taken to vulcanize 30%, 50% and 90% of the rubber respectively.

[0027] The term “ N-330, N-550, N-660” refers to varieties of carbon black which is used as reinforcing fillers in the rubber products. These varieties of carbon black are characterized based on their particle size , i.e. N-330 has particle size ranging 28 to 36 nm, N-550 having size in the range of 39 to 55 nm and N-660 has particle size in the range of 49 to 73 nm. Each carbon black possesses varied properties and accordingly impart different characteristics to the rubber compound. [0028] The term “rubber compound” in the present disclosure refers to the rubber mixture comprising the polymer with other additives. In the present disclosure the term “rubber compound” also refer to the final rubber mixture obtained from the process of the present disclosure. The rubber compound may also refer to processed or unprocessed final rubber mixture of the present disclosure. The terms final rubber mixture and rubber compound may be used interchangeably.

[0029] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods, and materials are now described. All publications mentioned herein are incorporated herein by reference.

[0030] The present disclosure is not to be limited in scope by the specific embodiments described herein, which are intended for the purposes of exemplification only. Functionally-equivalent products, compositions, and methods are clearly within the scope of the disclosure, as described herein.

[0031] The methods that have been conventionally used for mixing the rubber components are associated with the limitation of adding preheated oil as a processing aid in the mixing cycle, due to which the dump temperature of the final rubber mixture is increased to a temperature above than 150°C. This increase in dump temperature causes premature vulcanization or scorch or low process safety. Consequently, the cost of production and time of production of the final rubber mixture is high. To overcome the limitation, the present disclosure discloses a single stage mixing process that uses a cold oil for mixing of the rubber components. The cold oil that is added directly to the mixing cycle helps to reduce the dump temperature of the final rubber mixture to a temperature below 120°C. Consequently, this helps to increase the scorch time and provides good process safety. Also, the number of steps involved in manufacturing of tire components in the present disclosure is less which helps to reduce the time and cost of production and hence, economically viable.

[0032] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer, a peptizer, a soft carbon black, and at least one first additive sequentially in an internal mixer to obtain a first mixture; b. contacting the first mixture with a cold oil to obtain a second mixture; and c. kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C. [0033] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer, a peptizer, a soft carbon black and at least one first additive sequentially in an internal mixer to obtain a first mixture; b. contacting the first mixture with a cold oil to obtain a second mixture; and c. kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -116°C. In another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -114°C. In yet another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature of 112 °C.

[0034] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the polymer is an elastomer selected from the group consisting of block rubber, butadiene rubber, styrene butadiene rubber, ethylene -propylene-diene rubber (EPDM), natural rubber (NR), chloroprene rubber, isoprene rubber, nitrile rubber, butyl rubber, and combinations thereof; wherein the peptizer is selected from but are not limited to organo sulphur compounds, aromatic disulfide compounds, aromatic mercaptan compounds, halogenated pyridine, a halogenated pyrimidine, halogenated diazine, halogenated triazine, an aromatic halogenated thiol, diphenyl disulfide.

[0035] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the polymer is an elastomer selected from the group consisting of block rubber, butadiene rubber, styrene butadiene rubber, ethylene-propylene-diene rubber (EPDM), natural rubber (NR), and combinations thereof. In another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the polymer is an elastomer selected from the group consisting of block rubber, butadiene rubber, styrene butadiene rubber, and combinations thereof. In yet another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the polymer is an elastomer selected from the group consisting of block rubber, butadiene rubber and styrene butadiene rubber.

[0036] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the peptizer is organo sulphur compounds, aromatic disulfide compounds, aromatic mercaptan compounds, halogenated pyridine, a halogenated pyrimidine, halogenated diazine, halogenated triazine, an aromatic halogenated thiol, diphenyl disulfide.

[0037] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer selected from the group consisting of block rubber, butadiene rubber, styrene butadiene rubber, ethylene-propylene-diene rubber (EPDM), Natural rubber (NR), chloroprene rubber, Isoprene rubber, nitrile rubber, butyl rubber, and combinations thereof, a peptizer, a soft carbon black and at least one first additive sequentially in an internal mixer to obtain a first mixture; b. contacting the first mixture with a cold oil to obtain a second mixture; and c. kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C.

[0038] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the at least one soft carbon black is selected from the group consisting of N-330, N-550, N-660, and combinations thereof. In another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the at least one soft carbon black is N-330, N-550 or N-660. In yet another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the at least one soft carbon black is N-330 or N-550. In yet another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the at least one soft carbon black is N-330.

[0039] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the at least one first additive is selected from the group consisting of fillers, activators, antioxidants, adhesion promoters, coupling agent, and combinations thereof.

[0040] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the at least one first additive is selected from the group consisting of fillers selected from the group consisting of carbon black, silica, high abrasion furnace black (HAF), and combinations thereof; activators selected from the group consisting of zinc oxide, stearic acid, and combinations thereof; antioxidants selected from the group consisting of N-phenyl, N' - (1,3 dimethyl, butyl) -p-phenylene diamine, polymerised 1,2 dihydro 2,2,4 trimethyl quinoline, wax, mixed diaryl p -phenylenediamine, and combinations thereof; adhesion promoters selected from the group consisting of hydrocarbon resin, wood rosin, resorcinol formaldehyde resin, performance resin, phenol formaldehyde resin, cobalt salts, and combinations thereof; coupling agent selected from group consisting of silane, bis[3- (triethoxysilyl)propyl] disulphide, and combinations thereof.

[0041] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer selected from the group consisting of block rubber, butadiene rubber, styrene butadiene rubber, ethylene -propylene-diene rubber (EPDM), natural rubber (NR), chloroprene rubber, isoprene rubber, nitrile rubber, butyl rubber, and combinations thereof, a peptizer, a soft carbon black selected from the group consisting of N-330, N- 550, N-660, and combinations thereof and at least one first additive selected from the group consisting of fillers, activators, antioxidants, adhesion promoters, coupling agent, and combinations thereof sequentially in an internal mixer to obtain a first mixture; b. contacting the first mixture with a cold oil to obtain a second mixture; and c. kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C.

[0042] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the polymer has Mooney viscosity in the range of 50 to 80. In another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the polymer has Mooney viscosity in the range of 50 to 70. In yet another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the polymer has Mooney viscosity in the range of 50 to 60.

[0043] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer selected from the group consisting of block rubber, butadiene rubber, styrene butadiene rubber, ethylene -propylene-diene rubber (EPDM), natural rubber (NR), chloroprene rubber, isoprene rubber, nitrile rubber, butyl rubber, and combinations thereof having Mooney viscosity in the range of 50 to 80, a peptizer, a soft carbon black selected from the group consisting of N-330, N-550, N-660, and combinations thereof and at least one first additive selected from the group consisting of fillers, activators, antioxidants, adhesion promoters, coupling agent, and combinations thereof sequentially in an internal mixer to obtain a first mixture; b. contacting the first mixture with a cold oil to obtain a second mixture; and c. kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C.

[0044] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein mixing at least one polymer, a peptizer, a soft carbon black, and at least one first additive sequentially to obtain a first mixture is carried out at a temperature in the range of 70°C to 100°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 45 to 65 rpm. [0045] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein mixing at least one polymer, a peptizer, a soft carbon black, and at least one first additive sequentially to obtain a first mixture is carried out at a temperature in the range of 75 °C to 95 °C with pressure in the range of 1 to 12 MPa and at a stirring speed in the range of 46 to 62 rpm. In another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein mixing at least one polymer, a peptizer, a soft carbon black, and at least one first additive sequentially to obtain a first mixture is carried out at a temperature in the range of 76 °C to 93 °C with pressure in the range of 1 to 11 MPa and at a stirring speed in the range of 46 to 60 rpm.

[0046] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer, a peptizer, a soft carbon black and at least one first additive sequentially in an internal mixer to obtain a first mixture; b. contacting the first mixture with a cold oil to obtain a second mixture; and c. kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C and wherein mixing at least one polymer, a peptizer, a soft carbon black, and at least one first additive sequentially to obtain a first mixture is carried out at a temperature in the range of 70 °C to 100 °C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 45 to 65 rpm.

[0047] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer selected from the group consisting of block rubber, butadiene rubber, styrene butadiene rubber, ethylene -propylene-diene rubber (EPDM), natural rubber (NR), chloroprene rubber, isoprene rubber, nitrile rubber, butyl rubber, and combinations thereof having Mooney viscosity in the range of 50 to 80, a peptizer, a soft carbon black selected from the group consisting of N-330, N-550, N-660, and combinations thereof and at least one first additive selected from the group consisting of fillers, activators, antioxidants, adhesion promoters, coupling agent, and combinations thereof sequentially in an internal mixer to obtain a first mixture; b. contacting the first mixture with a cold oil to obtain a second mixture; and c. kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C and wherein mixing at least one polymer, a peptizer, a soft carbon black, and at least one first additive sequentially to obtain a first mixture is carried out at a temperature in the range of 70 °C to 100°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 45 to 65 rpm.

[0048] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the cold oil is selected from the group consisting of light naphthenic oil, treated distillate aromatic extract (TDAE) oil, paraffinic oil, naphthenic oil, aromatic oil, and combinations thereof. In another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the cold oil is selected from the group consisting of light naphthenic oil, treated distillate aromatic extract(TDAE) oil and paraffinic oil. In yet another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the cold oil is light naphthenic oil.

[0049] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer, a peptizer, a soft carbon black and at least one first additive sequentially in an internal mixer to obtain a first mixture; b. contacting the first mixture with a cold oil to obtain a second mixture; and c. kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C and wherein the cold oil is selected from the group consisting of light naphthenic oil, treated distillate aromatic extract(TDAE) oil, paraffinic oil, naphthenic oil, aromatic oil, and combinations thereof.

[0050] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer selected from the group consisting of block rubber, butadiene rubber, styrene butadiene rubber, ethylene -propylene-diene rubber (EPDM), natural rubber (NR), chloroprene rubber, isoprene rubber, nitrile rubber, butyl rubber, and combinations thereof having Mooney viscosity in the range of 50 to 80, a peptizer, a soft carbon black selected from the group consisting of N-330, N-550, N-660, and combinations thereof and at least one first additive selected from the group consisting of fillers, activators, antioxidants, adhesion promoters, coupling agent, and combinations thereof sequentially in an internal mixer to obtain a first mixture; b. contacting the first mixture with a cold oil selected from the group consisting of light naphthenic oil, treated distillate aromatic extract(TDAE) oil, paraffinic oil, naphthenic oil, aromatic oil, and combinations thereof to obtain a second mixture; and c. kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C and wherein mixing at least one polymer, a peptizer, a soft carbon black, and at least one first additive sequentially to obtain a first mixture is carried out at a temperature in the range of 70 °C to 100°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 45 to 65 rpm.

[0051] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the cold oil is at a temperature in the range of 30 to 40°C. In another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the cold oil is at a temperature in the range of 30 to 37°C.

[0052] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer, a peptizer, a soft carbon black and at least one first additive sequentially in an internal mixer to obtain a first mixture; b. contacting the first mixture with a cold oil to obtain a second mixture; and c. kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C and wherein the cold oil is at a temperature in the range of 30 to 40°C.

[0053] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer selected from the group consisting of block rubber, butadiene rubber, styrene butadiene rubber, ethylene -propylene-diene rubber (EPDM), natural rubber (NR), chloroprene rubber, isoprene rubber, nitrile rubber, butyl rubber, and combinations thereof having Mooney viscosity in the range of 50 to 80, a peptizer, a soft carbon black selected from the group consisting of N-330, N-550, N-660 and combinations thereof and at least one first additive selected from the group consisting of fillers, activators, antioxidants, adhesion promoters, coupling agent, and combinations thereof sequentially in an internal mixer to obtain a first mixture; b. contacting the first mixture with a cold oil selected from the group consisting of light naphthenic oil, treated distillate aromatic extract (TDAE) oil, paraffinic oil, naphthenic oil, aromatic oil, and combinations thereof to obtain a second mixture; and c. kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C and wherein mixing at least one polymer, a peptizer, a soft carbon black, and at least one first additive sequentially to obtain a first mixture is carried out at a temperature in the range of 70 °C to 100°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 45 to 65 rpm and wherein the cold oil is at a temperature in the range of 30 to 40°C.

[0054] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein contacting the first mixture with a cold oil is carried out at a temperature in the range of 80 °C to 120°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 35 to 65 rpm. In another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein contacting the first mixture with a cold oil is carried out at a temperature in the range of 85 °C to 120°C with pressure in the range of 1 to 12MPa and at a stirring speed in the range of 37 to 55 rpm.

[0055] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer selected from the group consisting of block rubber, butadiene rubber, styrene butadiene rubber, ethylene -propylene-diene rubber (EPDM), natural rubber (NR), chloroprene rubber, isoprene rubber, nitrile rubber, butyl rubber, and combinations thereof having Mooney viscosity in the range of 50 to 80, a peptizer, a soft carbon black selected from the group consisting of N-330, N-550, N-660, and combinations thereof and at least one first additive selected from the group consisting of fillers, activators, antioxidants, adhesion promoters, coupling agent, and combinations thereof sequentially in an internal mixer at a temperature in the range of 70 °C to 100°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 45 to 65 rpm to obtain a first mixture; b. contacting the first mixture with a cold oil selected from the group consisting of light naphthenic oil, treated distillate aromatic extract(TDAE) oil, paraffinic oil, naphthenic oil, aromatic oil, and combinations thereof at a temperature in the range of 80 °C to 120°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 35 to 65 rpm to obtain a second mixture; and c. kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C and wherein the cold oil is at a temperature in the range of 30 to 40°C.

[0056] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the at least second additive is selected from the group of crosslinking agents, accelerators, retarders, and combinations thereof.

[0057] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the at least second additive is selected from the group of crosslinking agents selected from hexakismethoxymethylmelamine (HMMM), insoluble Sulphur, and combinations thereof; accelerators selected from N,N'-Dicyclohexyl-2-benzothiazole sulfonamide (DCBS), 2-2’-Dithiobis(benzothiazole)(MBTS), N-tert-butyl-2-benzothiazyl sulfonamide (TBBS), and combinations thereof; retarders selected from the group consisting of cyclohexylthiophthalimide(CTP), benzoic acid, salicyclic acid, phthalic acid, sulfonamide, and combinations thereof. [0058] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer, a peptizer, a soft carbon black and at least one first additive sequentially in an internal mixer to obtain a first mixture; b. contacting the first mixture with a cold oil to obtain a second mixture; and c. kneading the second mixture with at least one second additive selected from the group of crosslinking agents, accelerators, retarders, and combinations thereof to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C.

[0059] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer selected from the group consisting of block rubber, butadiene rubber, styrene butadiene rubber, ethylene -propylene-diene rubber (EPDM), natural rubber (NR), chloroprene rubber, isoprene rubber, nitrile rubber, butyl rubber, and combinations thereof having Mooney viscosity in the range of 50 to 80, a peptizer, a soft carbon black selected from the group consisting of N-330, N-550, N-660 and combinations thereof and at least one first additive selected from the group consisting of fillers, activators, antioxidants, adhesion promoters, coupling agent and combinations thereof sequentially in an internal mixer at a temperature in the range of 70 °C to 100°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 45 to 65 rpm to obtain a first mixture; b. contacting the first mixture with a cold oil selected from the group consisting of light naphthenic oil, treated distillate aromatic extract (TDAE) oil, paraffinic oil, naphthenic oil, aromatic oil, and combinations thereof at a temperature in the range of 80 °C to 120°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 35 to 65 rpm to obtain a second mixture; and c. kneading the second mixture with at least one second additive selected from the group of crosslinking agents, accelerators, retarders, and combinations thereof to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120 C and wherein the cold oil is at a temperature in the range of 30 to 40°C.

[0060] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein kneading the second mixture with at least one second additive to obtain a final rubber mixture is carried out at a temperature in the range of 100 °C to 120°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 5 to 50 rpm.

[0061] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein kneading the second mixture with at least one second additive to obtain a final rubber mixture is carried out at a temperature in the range of 102 °C to 117°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 5 to 50 rpm. In another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein kneading the second mixture with at least one second additive to obtain a final rubber mixture is carried out at a temperature in the range of 105 °C to 115°C with pressure in the range of 2 to lOMPa and at a stirring speed in the range of 7 to 40 rpm.

[0062] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer, a peptizer, a soft carbon black and at least one first additive sequentially in an internal mixer to obtain a first mixture; b. contacting the first mixture with a cold oil to obtain a second mixture; and c. kneading the second mixture with at least one second additive at a temperature in the range of 100 °C to 120°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 5 to 50 rpm to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C.

[0063] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer selected from the group consisting of block rubber, butadiene rubber, styrene butadiene rubber, ethylene -propylene-diene rubber (EPDM), natural rubber (NR), chloroprene rubber, isoprene rubber, nitrile rubber, butyl rubber, and combinations thereof having Mooney viscosity in the range of 50 to 80, a peptizer, a soft carbon black selected from the group consisting of N-330, N-550, N-660, and combinations thereof and at least one first additive selected from the group consisting of fillers, activators, antioxidants, adhesion promoters, coupling agent, and combinations thereof sequentially in an internal mixer at a temperature in the range of 70 °C to 100°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 45 to 65 rpm to obtain a first mixture; b. contacting the first mixture with a cold oil selected from the group consisting of light naphthenic oil, treated distillate aromatic extract (TDAE) oil, paraffinic oil, naphthenic oil, aromatic oil, and combinations thereof at a temperature in the range of 80 °C to 120°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 35 to 65 rpm to obtain a second mixture; and c. kneading the second mixture with at least one second additive at a temperature in the range of 100 °C to 120°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 5 to 50 rpm to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C and wherein the cold oil is at a temperature in the range of 30 to 40°C.

[0064] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the final rubber mixture has scorch time in the range of 25 to 30 minutes. In another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the final rubber mixture has scorch time in the range of 26 to 29 minutes. In yet another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the final rubber mixture has scorch time of 28 minutes. [0065] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer, a peptizer, a soft carbon black and at least one first additive sequentially in an internal mixer to obtain a first mixture; b. contacting the first mixture with a cold oil to obtain a second mixture; and c. kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C and wherein the final rubber mixture has scorch time in the range of 25 to 30 minutes. [0066] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer selected from the group consisting of block rubber, butadiene rubber, styrene butadiene rubber, ethylene -propylene-diene rubber (EPDM), natural rubber (NR), chloroprene rubber, isoprene rubber, nitrile rubber, butyl rubber, and combinations thereof having mooney viscosity in the range of 50 to 80, a peptizer, a soft carbon black selected from the group consisting of N-330, N-550, N-660, and combinations thereof and at least one first additive selected from the group consisting of fillers, activators, antioxidants, adhesion promoters, coupling agent and combinations thereof sequentially in an internal mixer at a temperature in the range of 70 °C to 100°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 45 to 65 rpm to obtain a first mixture; b. contacting the first mixture with a cold oil selected from the group consisting of light naphthenic oil, treated distillate aromatic extract (TDAE) oil, paraffinic oil, naphthenic oil, aromatic oil, and combinations thereof at a temperature in the range of 80 °C to 120°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 35 to 65 rpm to obtain a second mixture; and c. kneading the second mixture with at least one second additive at a temperature in the range of 100 °C to 120°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 5 to 50 rpm to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120 C and wherein the cold oil is at a temperature in the range of 30 to 40°C and wherein the final rubber mixture has scorch time in the range of 25 to 30 minutes.

[0067] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the final rubber mixture is extruded in the form of sheets or pellets. In another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the final rubber mixture is extruded in the form of sheets. In yet another embodiment of the present disclosure, there is provided a single stage process for mixing rubber components as disclosed herein, wherein the final rubber mixture is extruded in the form of pellets.

[0068] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer, a peptizer, a soft carbon black and at least one first additive sequentially in an internal mixer to obtain a first mixture; b. contacting the first mixture with a cold oil to obtain a second mixture; and c. kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C and wherein the final rubber mixture is extruded in the form of sheets or pellets.

[0069] In an embodiment of the present disclosure, there is provided a single stage process for mixing rubber components, the process comprising: a. mixing at least one polymer selected from the group consisting of block rubber, butadiene rubber, styrene butadiene rubber, ethylene -propylene-diene rubber (EPDM), natural rubber (NR), chloroprene rubber, isoprene rubber, nitrile rubber, butyl rubber, and combinations thereof having Mooney viscosity in the range of 50 to 80, a peptizer, a soft carbon black selected from the group consisting of N-330, N-550, N-660, and combinations thereof and at least one first additive selected from the group consisting of fillers, activators, antioxidants, adhesion promoters, coupling agent, and combinations thereof sequentially in an internal mixer at a temperature in the range of 70 C to 100 C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 45 to 65 rpm to obtain a first mixture; b. contacting the first mixture with a cold oil selected from the group consisting of light naphthenic oil, treated distillate aromatic extract (TDAE) oil, paraffinic oil, naphthenic oil, aromatic oil, and combinations thereof at a temperature in the range of 80 °C to 120°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 35 to 65 rpm to obtain a second mixture; and c. kneading the second mixture with at least one second additive at a temperature in the range of 100 °C to 120°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 5 to 50 rpm to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C and wherein the cold oil is at a temperature in the range of 30 to 40°C and wherein the final rubber mixture has scorch time in the range of 25 to 30 minutes and wherein the final rubber mixture is extruded in the form of sheets or pellets.

[0070] In an embodiment of the present disclosure, there is provided a rubber compound obtained by the process, the process comprising: a. mixing at least one polymer, a peptizer, a soft carbon black and at least one first additive sequentially in an internal mixer to obtain a first mixture; b. contacting the first mixture with a cold oil to obtain a second mixture; and c. kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C. [0071] In an embodiment of the present disclosure, there is provided a rubber compound obtained by the process, the process comprising: a. mixing at least one polymer selected from the group consisting of block rubber, butadiene rubber, styrene butadiene rubber, ethylene -propylene-diene rubber (EPDM), natural rubber (NR), chloroprene rubber, isoprene rubber, nitrile rubber, butyl rubber, and combinations thereof having Mooney viscosity in the range of 50 to 80, a peptizer, a soft carbon black selected from the group consisting of N-330, N-550, N-660, and combinations thereof and at least one first additive selected from the group consisting of fillers, activators, antioxidants, adhesion promoters, coupling agent, and combinations thereof sequentially in an internal mixer at a temperature in the range of 70 °C to 100°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 45 to 65 rpm to obtain a first mixture; b. contacting the first mixture with a cold oil selected from the group consisting of light naphthenic oil, treated distillate aromatic extract (TDAE) oil, paraffinic oil, naphthenic oil, aromatic oil, and combinations thereof at a temperature in the range of 80 °C to 120°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 35 to 65 rpm to obtain a second mixture; and c. kneading the second mixture with at least one second additive at a temperature in the range of 100 °C to 120°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 5 to 50 rpm to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C and wherein the cold oil is at a temperature in the range of 30 to 40°C and wherein the final rubber mixture has scorch time in the range of 25 to 30 minutes and wherein the final rubber mixture is extruded in the form of sheets or pellets.

[0072] In an embodiment of the present disclosure, there is provided an article comprising the final rubber mixture obtained by the process as disclosed herein, wherein the article is an automotive tire, conveyer belts, belts, treads, sidewalls of tires or other parts of tire.

[0073] In an embodiment of the present disclosure, there is provided an article comprising the final rubber mixture obtained by the process comprising: a. mixing at least one polymer, a peptizer, a soft carbon black and at least one first additive sequentially in an internal mixer to obtain a first mixture; b. contacting the first mixture with a cold oil to obtain a second mixture; and c. kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C, wherein the article is an automotive tire, conveyer belts, belts, treads, sidewalls of tires or other parts of tire.

[0074] In an embodiment of the present disclosure, there is provided an article comprising the final rubber mixture obtained by the process comprising: a. mixing at least one polymer selected from the group consisting of block rubber, butadiene rubber, styrene butadiene rubber, ethylene-propylene-diene rubber (EPDM), natural rubber (NR), chloroprene rubber, isoprene rubber, nitrile rubber, butyl rubber, and combinations thereof having Mooney viscosity in the range of 50 to 80, a peptizer, a soft carbon black selected from the group consisting of N-330, N-550, N-660 and combinations thereof and at least one first additive selected from the group consisting of fillers, activators, antioxidants, adhesion promoters, coupling agent and combinations thereof sequentially in an internal mixer at a temperature in the range of 70 °C to 100°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 45 to 65 rpm to obtain a first mixture; b. contacting the first mixture with a cold oil selected from the group consisting of light naphthenic oil, treated distillate aromatic extract(TDAE) oil, paraffinic oil, naphthenic oil, aromatic oil, and combinations thereof at a temperature in the range of 80 °C to 120°C with pressure in the range of 1 to 15 MPa and at a stirring speed in the range of 35 to 65 rpm to obtain a second mixture; and c. kneading the second mixture with at least one second additive at a temperature in the range of 100 °C to 120°C with pressure in the range of 1 to 15MPa and at a stirring speed in the range of 5 to 50 rpm to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C and wherein the cold oil is at a temperature in the range of 30 to 40°C and wherein the final rubber mixture has scorch time in the range of 25 to 30 minutes and wherein the final rubber mixture is extruded in the form of sheets or pellets and wherein the article is an automotive tire, conveyer belts, belts, treads, sidewalls of tires or other parts of tire. [0075] In an embodiment of the present disclosure, there is provided a rubber compound obtained by the process as disclosed herein, the compound comprising: a) 50 to 100 phr of at least one polymer; b) 0.01 to 1.0 phr of a peptizer; c) 20 to 60 phr of a soft carbon black; d) 0.5 to 65 phr of at least one first additive; e) 5 to 20 phr of a cold oil and f) 0.1 to 15 phr of at least second additive.

[0076] In an embodiment of the present disclosure, there is provided a rubber compound obtained by the process as disclosed herein, the compound comprising: a) 50 to 100 phr of at least one polymer; b) 0.01 to 1.0 phr of a peptizer; c) 20 to 60 phr of a soft carbon black; d) 0.5 to 65 phr of at least one first additive; e) 5 to 20 phr of a cold oil and f) 0.1 to 15 phr of at least second additive, the process comprising: (i). mixing at least one polymer, a peptizer, a soft carbon black and at least one first additive sequentially in an internal mixer to obtain a first mixture; (ii). contacting the first mixture with a cold oil to obtain a second mixture; and (iii). kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C.

[0077] In an embodiment of the present disclosure, there is provided a rubber compound obtained by the process as disclosed herein, the compound comprising: a) 50 to 100 phr of at least one polymer selected from the group consisting of block rubber, butadiene rubber, styrene butadiene rubber, ethylene-propylene-diene rubber (EPDM), natural rubber (NR), chloroprene rubber, isoprene rubber, nitrile rubber, butyl rubber, and combinations thereof; b) 0.01 to 1.0 phr of a peptizer; c) 20 to 60 phr of a soft carbon black selected from the group consisting of N-330, N-550, N-660, and combinations thereof; d) 0.5 to 65 phr of at least one first additive selected from the group consisting of fillers, activators, antioxidants, adhesion promoters, coupling agent ; e) 5 to 20 phr of a cold oil selected from the group consisting of light naphthenic oil, treated distillate aromatic extract (TDAE) oil, paraffinic oil, naphthenic oil, aromatic oil, and combinations thereof and f) 0.1 to 15 phr of at least second additive selected from the group of crosslinking agents, accelerators, retarders, and combinations thereof, the process comprising: (i). mixing at least one polymer, a peptizer, a soft carbon black and at least one first additive sequentially in an internal mixer to obtain a first mixture; (ii). contacting the first mixture with a cold oil to obtain a second mixture; and (iii). kneading the second mixture with at least one second additive to obtain a final rubber mixture, wherein the final rubber mixture is discharged out of the internal mixer with dump temperature in the range of 110 -120°C

[0078] Although the subject matter has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternate embodiments of the subject matter, will become apparent to persons skilled in the art upon reference to the description of the subject matter. It is therefore contemplated that such modifications can be made without departing from the spirit or scope of the present subject matter as defined.

EXAMPLES

[0079] The disclosure will now be illustrated with the working examples, which is intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one ordinary person skilled in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice of the disclosed methods and compositions, the exemplary methods, devices and materials are described herein. It is to be understood that this disclosure is not limited to particular methods, and experimental conditions described, as such methods and conditions may apply.

[0080] The forthcoming examples explains that how the present disclosure provides a single stage mixing process of rubber components. The process comprises the use of cold oil added to the first mixture containing the polymer, peptizer and the first additive. The single stage mixing process is a simple process compared to the conventional and two stage mixing process. The final rubber mixture has lowered dump temperature and hence results in a scorch safe process. The process of mixing rubber components disclosed in the present disclosure is energy saving, cost effective and also, the cost of implementation is minimal

EXAMPLEI

Materials and Methods

[0081] For the purpose of the present disclosure, following raw material grades were procured commercially: TSR20 - Standard Thailand Rubber - 20, Styrene Butadiene Rubber, peptizer-2, 2'-dibenzamido diphenyldisulfide (DBDD), Carbon black Grades - N330, N339(HAF) and light naphthenic oil of code 388B. Internal mixer used is Kobe make BB430.

[0082] Mooney viscosity and Mooney scorch properties of rubber mixtures were measured using an Alpha Technologies MV2000 Mooney viscometer according to ASTM D 1646-04 method.

[0083] Cure properties were measured with an Alpha Technologies MDR / PREMIER RPA rheometer at 150°C, 0.5° arc and 1.67 Hz according to ASTM D-5289. The shore A hardness rubber samples were measured according to ASTM-D2240-03. The tensile properties of rubber samples were measured according to ASTM D412. The samples were cured in the hydraulic rubber curing press and tested under different ageing conditions according to ASTM D 2229-02 method.

Single stage mixing process of rubber components of the present disclosure.

[0084] The process of single stage mixing of rubber components of the present disclosure comprised a) mixing at least one polymer, a peptizer, a soft carbon black and at least one first additive sequentially in an internal mixer to obtain a first mixture; b) contacting the first mixture with a cold oil to obtain a second mixture; and c) kneading the second mixture with at least one second additive to obtain a final rubber mixture. Table 1 illustrates the critical parameters employed in the internal mixer during addition of various rubber components.

Table 1 [0085] Table 1 shows the sequential addition of rubber components in single stage mixing process of the present disclosure. About 50 to 100 phr of block natural rubber and styrene butadiene rubber was mixed with 0.01 to 1.0 phr of the peptizer, 20 to 60 phr of N-330 and 0.5 to 65 phr of first additives consisting of fillers, activators, antioxidants, adhesion promoters, coupling agent at a temperature in the range of 70 to 100°C under a pressure of 1 to 15MPa and at a speed 45 to 65 rpm to obtain the first mixture. Then cold light naphthenic oil of about 5 to 20 phr stored at a temperature of 30 to 40°C was contacted with the first mixture at a temperature in the range of 80 to 120°C under a pressure of 1 to 15MPa and at a speed 35 to 65 rpm to obtain the second mixture. Further to the second mixture, 0.1 to 15phr of second additives consisting of crosslinking agents, accelerators, retarders were kneaded at a temperature in the range of 100 to 120°C under a pressure of 1 to 15MPa and at a speed 5 to 50 rpm to obtain the final rubber mixture which can be analysed for its physical, mechanical, rheological properties and mooney viscosity.

[0086] Table 2 shows the actual working of single stage mixing process of rubber components. Table 2 shows the process parameters such as time, temperature power and energy maintained at every sequential addition of the rubber components. The Table 2 further describes the rotor mixing speed and the pressure maintained throughout the mixing process. In the actual process, 70 phr of block natural rubber and 30phr of styrene butadiene rubber was mixed with 0.15 phr of 2,2'-dibenzamido diphenyldisulfide (DBDD) at a temperature of 77.2°C under a ram cylinder pressure of IMPa and at a speed of 46 rpm. Mooney viscosity of the polymer was 62.2 and was found to be in the preferable range of 50 to 80. Subsequently, the ram cylinder of internal mixer was kept down wherein the pressure was at 2 MPa and at a speed of 57 rpm. The internal mixer comprising the rubber and the peptizer was then maintained at temperature of 78.1°C with a pressure of 2 MPa and at a speed of 59 rpm followed by bringing up the ram cylinder and at temperature of 93 °C with a pressure of 11 MPa and at a speed of 60 rpm. Further into the internal mixer about 45 phr of N330 carbon black was added at temperature of 95.8 C with a pressure of 8 MPa and at a speed of 56 rpm, then the ram cylinder was brought down allowing the mixture to be at a temperature of 90°C with a pressure of 2 MPa and at a speed of 50 rpm. This was then followed by addition of 3.5 phr of zinc oxide, 1.2 phr of stearic acid, l.Ophr of TMQ, 1.0 of hydrocarbon resin, 0.9 phr of resorcinol formaldehyde resin and 0.75 phr of phenol formaldehyde at temperature of 84°C with a pressure of 9 MPa and at a speed of 49 rpm. Again, the ram down was done, and the first mixture was obtained which was at a temperature of 120°C.

[0087] To this first mixture, 12.2 phr of light naphthenic oil was added at temperature of 120.1°C with a pressure of 11 MPa and at a speed of 50 rpm. Light naphthenic oil was stored at a temperature in the range of 30°C to 37°C was added to the first mixture to obtain the second mixture . No preheating of the oil was essential, and the mixing was easier and simple. It can be noted that the temperature of the internal mixer got lowered up to 90.2°C and the mixing was continued. The second mixture was still maintained at a much lower temperature of 106.8°C. To this second mixture, the second additives such as 0.3 phr of CTP retarder, 0.6 phr of accelerator MBTS, 0.55 phr of accelerator TBBS, 1.5 phr of crosslinking agent HMMM and 2.75 phr of insoluble sulphur were added at temperature of 107°C with a pressure of 8 MPa and at a speed of 34 rpm for a time period in the range of one minute to 3 minutes with ram up and down process and the final rubber mixture was obtained. It can be observed that the final rubber mixture was at a temperature i.e., dump temperature of 112.2°C. The dump temperature was much lower compared to dump temperature in the conventional mixing process.

Table 2

[0088] Mooney viscosity of the carbon black N-330 was ensured to be in the range of 50 to 60 which was found to be desirable for the single stage mixing process of the present disclosure. Mooney viscosity of the final rubber mixture was found to be 62.2. Example 2

Two stage mixing of rubber components - Non-working example

[0089] In the general process of regular mixing of the rubber components, two stage mixing is implemented. Table 3 and 4 shows the two stage mixing i.e., the master stage and the final stage in mixing the rubber components.

Table 3 Table 4

[0090] Table 4 details the master stage mixing of rubber components which involved the addition polymer with all additives and carbon black up to a temperature of 130°C. Then oil was added at a temperature of 150 °C and the mixture was processed to obtain the master batch. It can be observed that the addition of oil to the mixture of rubber components is carried out at a higher temperature as compared to the single stage mixing process of the present disclosure. Further, Table 4 illustrates the second stage of mixing i.e. the final stage, the master batch from stage 1 was taken and the additives were added. The power required for this process is also higher than the single stage mixing process of the present disclosure. This clearly shows that the two stage mixing process which uses high power and higher temperature is much more energy consuming and economically less favoured process.

[0091] Table 5 and Table 6 shows the actual implementation of two stage mixing of rubber components. Step by step addition of all the rubber components are detailed in the table 5 and 6. Also the process parameters such as time of mixing, temperature in the internal mixer, the power and energy used along with pressure maintained, the rotating speed of the internal mixer is stated.

Table 5

Table 6 [0092] From Table 5 it can be seen that the temperature for mixing the rubber components goes as high as up to 150°C the rubber mixture. And from Table 5 and 6 it can be observed that the power used throughout the mixing process is higher compared to the single stage mixing process of the present disclosure. Further the dump temperature of the final rubber mixture is 113°C which is higher than the dump temperature of the final rubber mixture from single stage mixing process.

From the above working and non-working examples, it can be concluded that the power consumption in single stage mixing process was reduced much more as compared with the regular two stage mixing of the rubber components for preparation of a rubber composition of the same compounding formulation. Also, the single stage mixing process eliminates two steps i.e. 1st mixing [master batch - without curative] at 150 — 160°C range and homogenization mixing/ viscosity reduction stage at 150°C Hence, the single stage mixing process is cost effective and implementation is easier and economic. Further higher temperatures involved in the regular mixing process might result in undesired properties or reactions. Higher temperatures might break down the polymers or cause side reactions resulting in unwanted products. The lower the dump temperature faster the rubber mixture would get cooled and would prevent any precuring. Thus, the mixing temperature and the dump temperature are lower i.e. in the range of 110 to 120°C appropriate for the process of mixing the rubber components and to ensure the desired properties of the rubber compound.

Example 3

Characterisation of the final rubber mixture

Scorch time of the final rubber mixture of the present disclosure

[0093] The scorch time of the final rubber mixture obtained from the single stage mixing of the present disclosure is 28 minutes, which is higher than the minimum requirement of 23 minutes. Thus, the process is scorch safe and the scorch time is greater than the minimum requirement. The scorch time for the rubber mixture vis a vis the two stage mixing process is 27 minutes which is lesser than the scorch time of the final rubber mixture of the present disclosure. Thus, the use of cold oil and the single stage mixing process favoured the scorch time and the ensured the process to be scorch safe.

Properties of the final rubber mixture of the present disclosure [0094] Table 7 shows the various physical parameters, regular and rapid rheological properties and the carbon black dispersion measured for the final rubber mixture of the present disclosure. It can be observed from Table 7 that the final rubber mixture obtained from single stage mixing process showed improved properties.

Table 7

[0095] The present disclosure had revealed a single stage mixing process of rubber components and the use of cold oil during the mixing process. In the mixing process of the known art, oil is added as a processing aid, but it is always preheated and hence after been added to the mixing cycle, the temperature of the mixture goes up to 100 °C which eventually increases the dump temperature of the compound. However, in the mixing of the present disclosure, the preheating was avoided, and cold oil was added directly to the mixing cycle. This helped to reduce the temperature of the compound during mixing to below 90°C after the point of oil addition and hence the dump temperature of the final rubber mixture also reduced to below 120°C. Thus, in the mixing process of the present disclosure, two stages of mixing process was eliminated and hence the rubber compound properties such as strength related properties i.e. mechanical strength and durability improved due to preservation of strength of molecules. Additionally, process safety improved due to lower heat exposure and further saving power while still achieving a good scorch safety for the rubber compound.

Advantages of the present disclosure

[0096] The present disclosure discloses a single stage mixing process of rubber components which yields a final rubber mixture with a dump temperature in the range of 110 °C to 120°C. The rubber mixture in the present disclosure is processed at lower temperature and thereby lowers the power consumption. Thus, the process of present disclosure is an energy saving process and is cost effective. Processing at a lower temperature eliminates the breakdown of the polymer and any other side reactions while mixing. Further the process uses the addition of cold oil at temperature in the range of 30 to 40°C which favors the lowering of the temperature of the process of mixing the rubber components. No preheating of the oil is carried out in the process of the present disclosure thereby eliminates that step and making the mixing process simpler. Further the addition of cold oil reduces the dump temperature of the present disclosure compared to the other mixing processes, which favors the rubber compound with desired properties. When the dump temperature is lower the curing occurs faster thereby preventing any undesired reactions.