FORM 2
THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003
COMPLETE SPECIFICATION (See section 10, rule 13)
1. Title of the invention: A RUBBER COMPOSITION COMPRISING RECLAIMED
NATURAL RUBBER AS A TACKIFYING AGENT
2. Applicant(s)
NAME NATIONALITY ADDRESS
CEAT LIMITED Indian RPG HOUSE, 463, Dr. Annie Besant Road, Worli, Mumbai-Maharashtra 400030, India
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it
is to be performed.

FIELD OF INVENTION
[0001] The subject matter disclosed herein relates to the field of rubber compounds
and in particular relates to a rubber composition comprising natural tackifying agent.
BACKGROUND OF THE INVENTION
[0002] Rubber compounds, such as tires and belts are multi-component systems.
Especially in tires, multiple components are applied one over the other in building the
drum to give the final shape of an uncured tire before putting it into the curing mold.
Merging these multilayers of a tire becomes very difficult if the components are
deficient in tack. Besides tires, any other product where multiple rubber components
are assembled, tack plays an essential role in assembling the rubber components.
Tackifiers are, therefore chemicals that act as an adhesive between two surfaces that
are required to stick together.
[0003] Tackifying agents are used for improving tack in rubber compounds.
Commonly used tackifying agents are synthetic which include polymerized phenolic
formaldehyde. Tackifying agents play an important role in providing correct balance
between adhesion and cohesion in the rubber compounds.
[0004] There has been a constant effort in this field for obtaining tackifying agents as
they combine the different components and help to achieve rubber products of desired
properties for their use in various applications. CN1196010A discloses a non-phenolic
tackifying agent as a thermosetting pressure sensitive adhesive tape and for obtaining
a hydrocarbon elastomer. US3294866A discloses a rubber composition as tackifier
comprising synthetic rubber and non-reactive higher alkyl phenol resins.
[0005] Although a lot of efforts have been made to obtain tackifying agent from
different sources, there is still a need in the state of art to obtain tackifiers which can
be easily obtained, are cost-effective and at the same time retain and improve the tack
properties of rubber compounds.

SUMMARY OF THE INVENTION
[0006] In a first aspect of the present disclosure, there is provided a rubber composition
comprising: (a) one or more rubber; (b) one or more filler; (c) one or more additive;
and (d) one or more natural tackifying agent, wherein the one or more natural tackifying
agent is a reclaimed natural rubber.
[0007] In a second aspect of the present disclosure, there is provided a process for
preparing a rubber composition comprising: (i) one or more rubber; (ii) one or more
filler; (iii) one or more additive; and (iv) one or more natural tackifying agent, wherein
the one or more natural tackifying agent is a reclaimed natural rubber, said process
comprising: (a) obtaining one or more rubber; (b) obtaining one or more filler; (c)
obtaining one or more natural tackifying agent; and (d) contacting the one or more
rubber, the one or more filler, and the one or more natural tackifying agent to the one
or more additive, to obtain the rubber composition.
[0008] In a third aspect of the present disclosure, there is provided an article
comprising a rubber composition, said rubber composition comprising: (i) one or more
rubber; (ii) one or more filler; (iii) one or more additive; and (iv) one or more natural
tackifying agent, wherein the one or more natural tackifying agent is a reclaimed
natural rubber.
[0009] In a fourth aspect of the present disclosure, there is provided a use of a
reclaimed natural rubber as a tackifying agent in rubber compositions.
[0010] These and other features, aspects, and advantages of the present subject matter
will be better understood with reference to the following description. 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.
DETAILED DESCRIPTION OF THE INVENTION
[0011] 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
[0012] 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.
[0013] 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.
[0014] 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”.
[0015] 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.
[0016] The term “including” is used to mean “including but not limited to”.
“Including” and “including but not limited to” are used interchangeably.
[0017] 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 range
of 100-155°C should be interpreted to include not only the explicitly recited limits of

100°C to 155°C but also to include sub-ranges, such as 100-150°C, 105-155°C, and so
forth, as well as individual amounts, including fractional amounts, within the specified
ranges, such as 100.5°C, 120° C, and 149.2°C for example.
[0018] The term “one or more” is used to mean at least one and thus includes individual
components as well as mixtures/combinations.
[0019] The term “rpm” used herein refers to rotations/revolutions per minute, is a unit
well used in the field of rubber technology to define the speed of any rotating part of
the machine, in this disclosure especially an extruder machine and an underwater
pelletizer.
[0020] The term “phr” used herein refers to parts per hundred rubber/resin, it is a unit
well defined in the field of rubber technology to define the amount of ingredients used.
[0021] The term “reclaimed natural rubber” used herein refers to rubber recovered
from scrap rubber, which is often used to mix with the crude rubber to modify its
properties. It is to be understood that the “reclaimed natural rubber” also has “natural
rubber” as a component, therefore, the phr of the “reclaimed natural rubber” as a whole
is with respect to the “rubber” which is used as a component in the “rubber
composition” of the present disclosure except that for the “natural rubber” which is a
part of the “reclaimed natural rubber”.
[0022] The term “tackifying agent” used herein refers to chemical compounds used as
adhesives to increase the tack or the stickiness of the adhesive.
[0023] The term “natural tackifying agent” refers to a tackifying agent that is generated
from a natural source rather than a synthetic one.
[0024] The term “ML(1+4) @ 100oC” used herein refers to conditions maintained
while performing viscosity analysis on a sample of rubber or any other compound. It
indicates the effect of temperature and time on the viscosity of rubber compounds. It is
measured in terms of torque, required to rotate the disk embedded in the
rubber/compound under specified conditions. Normally a pre-heat period is given to
the elastomer following which the disc starts to rotate. The highest viscosity is recorded

initially which later starts to decrease with time and reaches its lowest value. Viscosity measured with a large rotor is twice of that measured with a small rotor. Viscosity is measured in Mooney Units (MU) denoted herein by M. With reference to present disclosure, L refers to large rotor, 1 refers preheat time in units, 4 refers to time in minutes after starting the rotor at which reading is taken, and 100oC refers to the test temperature.
[0025] The term “ML 5 UP mins @ 125oC” used herein refers to time taken for 5 units up from the minimum mooney viscosity units recorded at 125oC.
[0026] The term “stress” used herein refers to a physical quantity which is a measure of the force applied on a material per unit area.
[0027] The term “strain” used herein refers to the amount of deformation experienced by a body in the direction of force applied. It is measured by dividing the magnitude of change in the parameter of the material by the original magnitude of the parameter. For example, if a material is elongated by a certain length through the application of force, strain is calculated as a change in length of the material divided by the original length of the material.
[0028] The term “rheo property” used herein refers to rheological properties of rubber measured using a rheometer which is an instrument used to measure the viscoelastic properties of rubber during its curing process. A sample of rubber is placed inside the cavity of the rheometer and a positive pressure is applied to it at a constant temperature. As the sample gets heated under pressure, its viscosity and torque vary with time which is recorded as ML and MH values. ML (moment lowest) is recorded at room temperature when the sample has minimum viscosity and torque. As further curing occurs, the torque exerted on the rotor increases and attains its maximum value denoted by MH (moment highest). All the measurements in the rheometric curve are recorded in terms of dN*m with varying time. With reference to the present disclosure, t’-30 and t’-95 refers to the time at which 30% of MH torque value and 95% of MH torque value has been achieved.

[0029] The term “TBR belt skim” used herein refers to truck bus radial belt skim
wherein belt skim refers to one of the rubber layer in a truck tire. It is denoted by B1046
sample code.
[0030] The term “LTR belt skim” used herein refers to light truck radial belt skim
wherein belt skim refers to one of the rubber layer in a truck tire. It is denoted by B7896
sample code.
[0031] The term “PCR tread base” used herein refers to passenger car radial tire tread
base. It is denoted by T5816 sample code.
[0032] The term “tread base” used herein refers to a part of a tire or wheel that makes
contact with the road or a rail.
[0033] The term “300% modulus” used herein refers to the force required for 300%
elongation of a material. It is measured in units of pressure as MPa or kg/cm2.
[0034] The term “tensile strength” used herein refers to the maximum load a material
can withstand before fracture, breaking, tearing, etc. It is measured in the units of
pressure as MPa or kg/cm2.
[0035] The term “elongation at break %” used herein refers to the percentage change
in elongation of a material at the instant of break.
[0036] The term “angle tear strength” used herein refers to tear resistance of a soft
vulcanized rubber when an angular test piece is employed. It is calculated by dividing
the load in kg with the thickness of the test specimen in cm and expressed as kg/cm.
[0037] The term “hardness shore A” used herein refers to the resistance of a material
to indentation. It is measured using a device called shore durometer. There are several
scales of a durometer out of which the two most common scales are A and D. Scale A
is used for measuring the hardness of soft materials, such as polymers, elastomers and
rubber.
[0038] The term “steel cord” used herein refers to reinforcement materials for products
of rubber or elastomeric products, such as tires or conveyor belts. It forms a part of

steel belt incorporated in a tire to provide wear resistance, durability, and appropriate
response to the direction of the tire.
[0039] The term “steel cord adhesion” used herein refers to a sticky bond, forming a
grip between a rubber material and a steel cord inside a tire.
[0040] The term “pull-out force” used herein refers to the force required to pull out the
steel material from the rubber material. It indicates the force with which the materials
are bind with each other. It is denoted in terms of load required in kilograms, times the
time taken in seconds.
[0041] The term “wire rubberisation” used herein refers to the extent to which the steel
material has been coated with the rubber material after the curing of tire. It is measured
in terms of percentage rubberisation.
[0042] The term “filler” used herein refers to substances added to resins or binders to
reduce cost and modify physical, thermal, mechanical, and electrical properties such as
bulk, strength, viscosity, weight, opacity, etc. Examples include silica, carbon black
and others.
[0043] The term “natural rubber” used herein refers to elastic substance obtained
naturally from the bark of trees. It majorly comprises of isoprene units and water along
with some other impurities.
[0044] The term “reclaimed natural rubber” used herein refers to rubber obtained from
chemically treated scrap rubber obtained from old and used tires and which is devoid
of any synthetic rubber.
[0045] The term “acetone extract” used herein refers to the product obtained from the
acetone extraction method which is a method of separating certain specific substances
from a sample of material using acetone as a solvent.
[0046] The term “cross-linking agent” used herein refers to substances that can form
chemical bonds between two molecular chains by a chemical reaction. Cross-linking
is important because it provides the substance, mechanical strength, and resistance to
heat, wear and attack by solvents.

[0047] The term “adhesion promoter” used herein refers to substances that are used to
encourage adhesion between two materials.
[0048] The term “adhesion” used herein refers to the joining of two different
substances due to attraction forces that hold them together.
[0049] The term “activator” used herein refers to products that have a strong activation
effect of increasing the vulcanization speed in the cross-linking reaction of diene
rubbers. Activators are required to achieve the desired vulcanisation and end-user
properties.
[0050] The term “antioxidant” used herein refers to substances that are used to protect
the rubber articles against the attack of oxygen.
[0051] The term “accelerator” used herein refers to compounding material used with a
cross-linking agent to increase the speed of vulcanization of rubber and enhance its
physical properties.
[0052] The term “processing aid” used herein refers to chemical additives added to
rubber compounds to improve their processability by lowering the viscosity and
increasing flexibility.
[0053] The term “process oil” used herein refers to a substance that provides a
chemical bond between two dissimilar materials, usually an inorganic and organic
material. Organosilanes are well suited in this application because of their ability to
incorporate an organic-compatible functionality and an inorganic-compatible
functionality within the same molecule.
[0054] The term “retarder” used herein refers to a substance added to rubber to delay
premature vulcanization during processing.
[0055] The term “zinc based salt of fatty acid” used herein refers to zinc salt of fatty
acids derived from palm oil. Examples include oleic acid, myristic acid, palmitic acid,
stearic acid, linoleic acid, and others.
[0056] The term “ASTM D1646” method refers to standard test methods for rubber
compositions to determine the viscosity, stress relaxation, and pre-vulcanization

characteristics using mooney viscometer. The term “ASTM E1131” refers to thermogravimetric analysis which provides exotherms, endotherms, weight loss on heating or cooling a sample.
[0057] 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.
[0058] 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.
[0059] As discussed in the background, there is a need for a tackifying agent that is economical, easily obtained and yet provides improved tack properties. An alternative to the synthetic tackifiers are those that can be obtained from natural products. Especially in the age of environmental awareness, recycling and reuse of materials have become very essential. With an increase in the population of the on-road and off-road vehicles, the old, used, and discarded tires are piling up in dump-yards all over the world. The polymeric material of these tires is either non-biodegradable or it degrades very slowly. In view of these points, if an alternate is provided which makes use of the rubber scraps and in turn avoids the use of harmful synthetic chemicals, it will be a commercial success overall, and be highly advantageous for the producer-consumer world.
[0060] One such responsible way of using post-consumer waste is the use of reclaimed rubber. Reclaimed rubber is any rubber recovered by grinding old tires and treating with alkali, oils, and plasticizers and often mixed with crude rubber for compounding. Reclaimed rubber is a vulcanized scrap rubber either natural or synthetic, that can be

reused in manufacturing different products in roofing, auto tubes, adhesives, belting, auto profiles, two-wheeler tires, and auto tires. Reclaimed rubber imparts process advantages which include lesser mixing time, temperature, and improved tack. Thus, the present disclosure provides a reclaimed rubber as a potential alternative to the synthetic resins. The reclaimed rubber of the present disclosure is obtained from the natural rubber latex, thus also called as reclaimed natural rubber. The inclusion of reclaimed natural rubber as a tackifying agent in the rubber composition makes the rubber article more economical and competent towards environmental issues. [0061] The present disclosure discloses a rubber composition comprising rubber, filler, additive, and a natural tackifying agent. The present disclosure also discloses a process for obtaining the rubber composition. In an embodiment, the present disclosure discloses a rubber composition which comprises a natural tackifying agent, said agent comprising reclaimed natural rubber. The rubber composition of the present disclosure makes prudent use of a tackifying agent which is non-synthetic, for obtaining articles having improved or the same qualities as those obtained using synthetic tackifying agents. Therefore, the composition of the present disclosure provides a significant advantage of providing a rubber composition having the same or superior qualities without using synthetic tackifying agents.
[0062] In an embodiment of the present disclosure, there is provided a rubber composition comprising: (a) one or more rubber; (b) one or more filler; (c) one or more additive; and (d) one or more natural tackifying agent, wherein the one or more natural tackifying agent is a reclaimed natural rubber.
[0063] In an embodiment of the present disclosure, there is provided a rubber composition comprising: (a) one or more rubber; (b) one or more filler; (c) one or more additive; and (d) one or more natural tackifying agent, wherein the one or more natural tackifying agent is a reclaimed natural rubber, and the one or more natural tackifying agent has a concentration in the range of 2-8 phr. In another embodiment of the present disclosure, there is provided a rubber composition as described herein, wherein the one

or more natural tackifying agent is a reclaimed rubber obtained from natural rubber
latex having a concentration in the range of 2-8 phr.
[0064] In an embodiment of the present disclosure, there is provided a rubber
composition comprising: (a) one or more rubber; (b) one or more filler; (c) one or more
additive; and (d) one or more natural tackifying agent, wherein the natural tackifying
agent is a reclaimed natural rubber obtained from natural rubber latex.
[0065] In an embodiment of the present disclosure, there is provided a rubber
composition comprising: (a) one or more rubber; (b) one or more filler; (c) one or more
additive; and (d) one or more natural tackifying agent, wherein the one or more natural
tackifying agent is a reclaimed natural rubber with concentration in the range of 2-8
phr, and the one or more filler has a concentration in the range of 5-70 phr. In another
embodiment, the one or more filler has a concentration in the range of 5-65 phr. In yet
another embodiment, the one or more filler has a concentration in the range of 5-63
phr.
[0066] In an embodiment of the present disclosure, there is provided a rubber
composition as described herein, wherein the natural rubber is in the form of sheets,
crepes, block rubber, preserved latex concentrates, and combinations thereof.
[0067] In an embodiment of the present disclosure, there is provided a rubber
composition as described herein, wherein the one or more filler can be selected from
the group consisting of carbon black N330, carbon black N660, carbon black N326,
silica, and combinations thereof. In another embodiment of the present disclosure, there
is provided a rubber composition as described herein, wherein the one or more filler
having concentration in the range of 5-70 phr selected from the group consisting of
carbon black N330, carbon black N660, carbon black N326, silica, and combinations
thereof.
[0068] In an embodiment of the present disclosure, there is provided a rubber
composition comprising: (a) one or more rubber selected from the group consisting of
natural rubber, polybutadiene rubber, and combinations thereof; (b) one or more filler

is selected from the group consisting of carbon black N330, carbon black N660, carbon black N326, silica, and combinations thereof; (c) one or more additive; and (d) one or more natural tackifying agent, wherein the one or more natural tackifying agent is a reclaimed natural rubber with concentration in the range of 2-8 phr, and the one or more filler has a concentration in the range of 5-70 phr.
[0069] In an embodiment of the present disclosure, there is provided a rubber composition comprising: (a) one or more rubber selected from the group consisting of natural rubber, polybutadiene rubber, and combinations thereof; (b) one or more filler is selected from the group consisting of carbon black N330, carbon black N660, carbon black N326, silica, and combinations thereof; (c) one or more additive selected from the group consisting of one or more cross-linking agent, one or more adhesion promoter, one or more activator, one or more antioxidant, one or more rubber accelerator, one or more processing aid, one or more coupling agent, one or more retarder, and combinations thereof; and (d) one or more natural tackifying agent is a reclaimed rubber obtained from natural rubber latex with a concentration in the range of 2-8 phr.
[0070] In an embodiment of the present disclosure, there is provided a rubber composition as described herein, wherein the one or more cross-linking agent is selected from the group consisting of hexamethoxymethylmelamine (HMMM), sulphur, and combinations thereof; the one or more adhesion promoter is selected from the group consisting of wood resin, resorcinol formaldehyde resin, performance resin, phenol formaldehyde resin, cobalt salts, and combinations thereof; the one or more activator is selected from the group consisting of zinc oxide, stearic acid, and combinations thereof; the one or more antioxidant is 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; the one or more accelerator is selected from the group consisting N-tert-butyl-2-benzothiazyl sulfonamide (TBBS), N,N'-dicyclohexyl-2-benzothiazole sulfonamide

(DCBS), and combinations thereof; the one or more processing aid is selected from the group consisting of zinc based salt of fatty acid, naphthenic oil, p-hydroxy benzoic acid, and combinations thereof; the one or more coupling agent is silane, and combinations thereof, and the one or more retarder is N-(cyclohexylthio) phthalimide (PVI).
[0071] In an embodiment of the present disclosure, there is provided a rubber composition as described herein, wherein the reclaimed natural rubber comprises: (a) a natural rubber having a concentration in the range of 75-90 % with respect to the reclaimed rubber; (b) carbon black having a concentration in the range of 4-10% with respect to the reclaimed rubber; (c) ash having a concentration in the range of 7-15% with respect to the reclaimed natural rubber; (d) acetone extract having a concentration in the range of 0-14% with respect to the reclaimed natural rubber.
[0072] In an embodiment of the present disclosure, there is provided a rubber composition as described herein, wherein the one or more cross-linking agent has a concentration in the range of 2.0-8.0 phr; the one or more adhesion promoter has a concentration in the range of 0.2-10.0 phr; the one or more activator has a concentration in the range of 1.0-10.0 phr; the one or more antioxidant has a concentration in the range of 0.2-3.0 phr; the one or more rubber accelerator has a concentration in the range of 0.20-2.0 phr; the one or more processing aid has a concentration in the range of 0.5-4.0 phr; the one or more coupling agent has a concentration in the range of 7.0-9.0 phr; and the one or more retarder has a concentration in the range of 0.1-0.3 phr. [0073] In an embodiment of the present disclosure, there is provided a rubber composition as described herein, wherein the one or more cross-linking agent has a concentration in the range of 2.1-7.6 phr; the one or more adhesion promoter has a concentration in the range of 0.33-4.0 phr; the one or more activator has a concentration in the range of 1.25-10.0 phr; the one or more antioxidant has a concentration in the range of 0.2-2.6 phr; the one or more rubber accelerator has a concentration in the range of 0.20-2.0 phr; the one or more processing aid has a concentration in the range of 0.6-

3.0 phr; the one or more coupling agent has a concentration in the range of 8.0-8.7 phr; and the one or more retarder has a concentration in the range of 0.1-0.25 phr. [0074] In an embodiment of the present disclosure, there is provided a process for preparing a rubber composition, said process comprising: (a) obtaining one or more rubber; (b) obtaining one or more filler; (c) obtaining one or more natural tackifying agent; and (d) contacting the one or more rubber, the one or more filler, and the one or more natural tackifying agent to the one or more additive, to obtain the composition. [0075] In an embodiment of the present disclosure, there is provided a process for preparing the rubber composition as described herein, wherein contacting the one or more rubber, the one or more filler, the one or more additive, and the one or more tackifying agent, to obtain the composition is done at a temperature in the range of 100-155°C for a time period in the range of 5-15 seconds, to obtain the rubber composition. In another embodiment of the present disclosure, wherein contacting the one or more rubber, the one or more filler, the one or more additive, and the one or more tackifying agent, to obtain the composition is done at a temperature in the range of 110-140°C for a time period in the range of 7-12 seconds, to obtain the rubber composition. In yet another embodiment of the present disclosure, wherein contacting the one or more rubber, the one or more filler, the one or more additive, and the one or more tackifying agent, to obtain the composition is done at a temperature of 120°C for a time of 10 seconds, to obtain the rubber composition.
[0076] In an embodiment of the present disclosure, there is provided a process for preparing the rubber composition as described herein, wherein mixing the one or more rubber, the one or more filler, the one or more additive, and the one or more tackifying agent, to obtain the composition is done at a mixing speed in the range of 85-105 rpm for a time period in the range of 7-10 minutes, at a temperature in the range of 100-155°C, to obtain the rubber composition. In another embodiment of the present disclosure, wherein mixing the one or more rubber, the one or more filler, the one or more additive, and the one or more tackifying agent, to obtain the composition is done

at a mixing speed in the range of 85-100 rpm for a time period in the range of 8-10 minutes, at a temperature in the range of 110-140°C, to obtain the rubber composition. In yet another embodiment of the present disclosure, wherein mixing the one or more rubber, the one or more filler, the one or more additive, and the one or more tackifying agent, to obtain the composition is done at a mixing speed of 90 rpm for a time period of 9 minutes, at a temperature of 120°C, to obtain the rubber composition. [0077] In an embodiment of the present disclosure, there is provided a process for preparing the rubber composition comprising: (1) one or more rubber; (2) one or more filler; (3) one or more additive; and (4) one or more natural tackifying agent, wherein the one or more natural tackifying agent is a reclaimed natural rubber, said process comprising: (a) obtaining one or more rubber; (b) obtaining one or more filler; (c) obtaining one or more natural tackifying agent; and (d) contacting the one or more rubber, the one or more filler, and the one or more natural tackifying agent to the one or more additive, to obtain the rubber composition.
[0078] In an embodiment of the present disclosure, there is provided an article comprising a rubber composition, said rubber composition comprising: (a) one or more rubber; (b) one or more filler; and (c) one or more natural tackifying agent, wherein the one or more natural tackifying agent is a reclaimed natural rubber with a concentration in the range of 2-8 phr.
[0079] In an embodiment of the present disclosure, there is provided an article comprising the rubber composition as described herein, wherein the article is selected from truck bus radial (TBR) belt, passenger car radial (PCR) tread base, light truck radial (LTR) belt, puncture sealant, tire body-ply compounds, two-wheeler (2W) tires, or three-wheeler (3W) tires.
[0080] In an embodiment of the present disclosure, there is provided use of a reclaimed natural rubber as a tackifying agent in rubber compositions.

EXAMPLES
[0081] 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.
[0082] The forthcoming examples explain that how the present disclosure provides a rubber composition with reclaimed natural rubber as a tackifying agent. The rubber composition also comprises an additive. The present disclosure also discloses a process for the preparation of rubber composition and employs the composition in various articles. The articles are then subjected to physical, chemical and mechanical studies in order to evaluate the effectiveness of reclaimed natural rubber as tackifying agent as compared to that of synthetic tackifying agents. The ratio of the components is essential to obtain the rubber composition of desired properties.
Materials and Methods
[0083] For the purpose of the present disclosure, reclaimed natural rubber was obtained commercially prepared by devulcanization of crude rubber. The carbon black filler was obtained from the incomplete combustion of petroleum oil fraction.
EXAMPLE 1
Analysis of reclaimed natural rubber
[0084] The reclaimed natural rubber was analyzed to understand the various
components present in it. The reclaimed rubber was subjected to mooney viscosity

analysis, acetone extraction method and Fourier transform infrared studies. Mooney viscosity measurements were done using ASTM D1646 method. Acetone extraction method was carried out by using ASTM E1131 method of TGA analysis which was used to estimate the percentage of various components in the reclaimed natural rubber. Table 1 demonstrated the recorded data for the reclaimed natural rubber of the present disclosure.
Table 1

TEST RECLAIMED REQUIREMENT AS PER TEST
PARAMETER NATURAL THE PRESENT
RUBBER DISCLOSURE
Mooney Viscosity 40.4 15-50 ASTM D1646
ML[1+4] @ 100° C
Acetone extract (w/w 2.11 0-14
% ) ASTM
E1131[TGA
Analysis]
Conventional 78.9 75-90 ASTM
Natural rubber E1131[TGA
content (w/w %) Analysis]
Synthetic rubber 0 NIL ASTM
content (w/w %) E1131[TGA Analysis]
Carbon black content 7.1 4-10 ASTM
(w/w %) E1131[TGA Analysis]
Ash content(w/w %) 11.9 7-15 ASTM
E1131[TGA
Analysis]
[0085] The reclaimed natural rubber was analyzed for its components and viscosity parameter and compared with the required specification. Table 1 reflects that the reclaimed natural rubber has a mooney viscosity of 40.4. It was also to be noted that the reclaimed natural rubber comprises 78.9 % of natural rubber, 7.1% of carbon black and 11.9 % of ash content, which are well within the range of the required specification. This indicated that the reclaimed natural rubber of the present disclosure is a potential candidate to act as a tackifying agent. Moreover, the reclaimed natural rubber is

essentially a natural rubber and does not contain any synthetic rubber component, thus imparting it benefits of being environmentally sound.
EXAMPLE 2
Preparation of rubber composition of the present disclosure
[0086] Various rubber articles such as TBR belt, PCR tread base and LTR belt of the present disclosure were prepared from components such as rubber, fillers, additives and tackifying agent. The tackifying agent of the present disclosure is a reclaimed natural rubber as disclosed in Example 1. The rubber components were selected from STR-20, RSS3, ISNR5, and polybutadiene rubber (R1678). The fillers were selected from carbon black N330, carbon black N660, carbon black N326, and silica. The additives were chosen from compounds categorized as cross-linking agent, adhesion promoter, activator, antioxidant, rubber accelerator, processing aid, coupling agent, and retarder.
[0087] The above said components in specific concentrations were contacted at 120oC for 10 seconds and subsequently mixed in a rotor at a speed of 90 rpm for 9 minutes to obtain the respective rubber compositions which were finally made into different articles like TBR belt, PCR tread base, and LTR belt. Table 2 demonstrated the rubber compositions present in TBR belt, PCR tread base and LTR belt comprising components in mentioned phr values, wherein ‘R’ stands for reference rubber composition comprising Koresin as a tackifying agent and ‘E’ stands for experimental rubber composition comprising reclaimed natural rubber (NR latex reclaim) as a tackifying agent. To provide a comparative study between the synthetic resin and reclaimed natural rubber as the tackifying agent, rubber compositions R and E are kept the same except for the tackifying agent used. R comprises Koresin whereas E comprises NR latex reclaim as the tackifying agent.

Table 2:

Compositions/ Weight in phr


PCR PCR
Trea Trea
TBR d d LTR LTR
Belt TBR base base Belt Belt
Categories Components [R] Belt [E] [R] [E] [R] [E]
Natur al Natural rubber (STR-20) 75.0 75.0

Natural rubber
rubbe r (RSS3) 80.0 80.0 53.0 53.0

Natural rubber
(ISNR5) 47.0 47.0

Synth
etic rubbe Polybutadiene
Rubber r rubber (R1678) 20.0 20.0 25.0 25.0
Reclai med natur
Tackifyin g agent al rubbe NR Latex reclaim

r (R2570) 4.0 4.0 2.5

Synth
etic
resin Koresin (R6214) 2.0 2.0 1.3
Silica (R729) 52.0 52.0

Carbon black
Filler s (N330) 22.0 22.0

Carbon black
(N660) 22.0 22.0

Carbon black
(N326) 5.0 5.0 62.0 62.0
Zinc Oxide
Additives Activ ator (R135) 8.0 8.0 4.5 4.5 10.0 10.0

Stearic acid
(R224) 1.5 1.5

N-Phenyl, N' -(1,3 Dimethyl, Butyl)-P-Phenylene
Diamine (R727) 1.0 1.0 2.5 2.5 1.0 1.0

Polymerised 1,2
Antio xidant Dihydro 2,2,4 Trimethyl
Quinoline (R280) 1.5 1.5 1.3 1.3 1.0 1.0
Wax (R582) 0.8 0.8 0.2 0.2
Mixed Diaryl p-phenylenediamine (R626) 1.0 1.0

Wood rosin
(R122) 2.0 2.0

Resorcinol
Adhes formaldehyde resin (R6220) 3.5 3.5

Performance resin
ion prom (I3370) 2.0 2.0

Performance
oter Resin (I3388) 1.0 1.0

Phenol
formaldehyde
resin (R619) 2.0 2.0 2.5 2.5 1.0 1.0

Cobalt adhesion
promoter (I4754) 0.36 0.36 0.89 0.89

Process aid
Proce (R6307) 1.0 1.0

p-Hydroxy
ssing aid benzoic acid (I8094) 0.75 0.75

Process oil
(R6347) 2.5 2.5

Coupl
ing agent Silane (R6266) 8.56 8.56

Crossl inking HMMM (R6200) 3.47 3.47

agent Sulphur (R5280) 5.44 5.44 2.23 2.23 7.5 7.5

Accel erator Accelerator TBBS (R732) 1.6 1.6

Accelerator DCBS (I2003) 1.7 1.7 0.5 0.5

Retar der PVI (R774) 0.15 0.15 0.1 0.1 0.2 0.2
Analysis of rubber articles
[0088] The rubber articles TBR belt, PCR tread base and LTR belt as prepared above were subjected to various analysis for their physical and mechanical properties, wherein the composition was tested for understanding the effect of reclaimed natural rubber as a tackifying agent. Qualitative details such as specific gravity, mooney viscosity and rheo properties were recorded. Stress strain studies on the cured original and thermally aged samples were done. The articles were also tested for steel cord adhesion taking original sample, thermally aged sample, humid chamber aged sample and salt aged sample. % change for each of the parameters were calculated. [0089] Table 3 depicts the data recorded for TBR Belt Skim (B1046) and provides a comparison between properties using koresin and reclaimed natural rubber as tackifying agents.
Table 3

R2570
R6214 Reclaimed natural
TABLE: 3 (Koresin -2 phr) rubber (NR latex reclaim – 4 phr)

B1046 (TBR BELT SKIM)
COMPOUND CODE 49-1-1 49-1-2

SAMPLE DETAILS [R] [E]

TBR Belt [R] TBR Belt [E]
Specific gravity 1.19 1.192
ML(1+4)@100oC 60 69
ML UP Mins @125oC 9.7 11.6

RHEO PROPERTY
MH-MH (dN-m) 24.59 23.86
t'-30 (Min) 7.59 7.95
t'-90 (Min) 19.05 19.23
STRESS STRAIN OF CURED COMPOUND: ORIGINAL
300% Modulus (Kg/cm2) 136 138
Tensile Strength (Kg/cm2) 210 205
Elongation at Break % 444 419
Angle Tear Strength (Kg/cm) 67 88
Hardness Shore A 83 80
STRESS STRAIN OF CURED COMPOUND: AGED: B1 (80oC * 7 Days
300% Modulus (Kg/cm2) 0 0
Tensile Strength (Kg/cm2) 161 162
Elongation at Break % 206 213
Angle Tear Strength (Kg/cm) 45 43
Hardness Shore A 88 88
% CHANGE AFTER AGEING
300% Modulus (Kg/cm2) -100 -100
Tensile Strength (Kg/cm2) -23.6 -20.6
Elongation at Break % -53.6 -49.1
Angle Tear Strength (Kg/cm) -32.1 -50.8
Hardness Shore A 5 8
OTHER PHYSICALS
STEEL CORD ADHESION OF CURED COMPOUND: ORIGINAL
Pull Out Force (Kg) 158 172
Wire Rubberisation % 90 90
STEEL CORD ADHESION OF CURED COMPOUND: AGED: B1 (80oC * 7 Days)
Pull Out Force (Kg) 142 147
Wire Rubberisation % 75 90
STEEL CORD ADHESION OF CURED COMPOUND: AGED: HMD (aged at high humidity)
Pull Out Force (Kg) 156 146
Wire Rubberisation % 90 90

STEEL CORD ADHESION OF CURED COMPOUND: AGED: SALT AGEING:8 DAYS
Pull Out Force (Kg) 75 64
Wire Rubberisation % 0 0
[0090] Data in Table 3 revealed that the sample with compound code 49-1-2 comprising 4 phr of reclaimed natural rubber demonstrates an increased mooney viscosity and comparative specific gravity as compared to the sample with compound code 49-1-1 comprising 4 phr synthetic koresin. A remarkable increase was observed to 88kg/cm in angle tear strength of original cure sample with compound code 49-1-2 while maintaining comparable 300% modulus, tensile strength, elongation at break % and hardness shore A. The data for the sample with compound code 49-1-2 also depicted desirable results for the % change after ageing, for tensile strength and elongation at break as 20.6% and 49.1% respectively. Moreover, the sample with compound code 49-1-2 recorded greater pull out force for original as well as aged samples. Thus, the sample with compound code 49-1-2 of TBR belt skim comprising the reclaimed natural rubber of the present disclosure qualifies as a better alternative to conventionally used articles comprising synthetic tackifying agents.
[0091] Table 4 reveals the data recorded for PCR Tread Base (T5816) and provides for a comparison between properties using koresin and reclaimed natural rubber as tackifying agents.
Table 4

TABLE: 4 R6214 (Koresin -2 phr) R2570 Reclaimed natural rubber (NR latex reclaim – 4 phr)

T5816 (PCR TREAD BASE)
COMPOUND CODE 49-1-3 [R] 49-1-4 [E]
SAMPLE DETAILS

PCR Tread base [R] PCR Tread base [E]

Specific gravity 1.098 1.089
ML(1+4)@100oC 48 50
ML UP Mins @125oC 14.7 13.1
RHEO PROPERTY
MH-MH (dN-m) 7.36 7.56
t'-30 (Min) 1.61 1.64
t'-90 (Min) 5.36 5.41
STRESS STRAIN OF CURED COMPOUND: ORIGINAL
300% Modulus (Kg/cm2) 49 52
Tensile Strength (Kg/cm2) 210 214
Elongation at Break % 712 688
Angle Tear Strength (Kg/cm) 46 43
Hardness Shore A 51 51
STRESS STRAIN OF CURED COMPOUND: AGED: B1 (80oC * 7 Days
300% Modulus (Kg/cm2) 95 100
Tensile Strength (Kg/cm2) 183 189
Elongation at Break % 469 488
Angle Tear Strength (Kg/cm) 49 48
Hardness Shore A 61 62
% CHANGE AFTER AGEING
300% Modulus (Kg/cm2) 95.5 90.6
Tensile Strength (Kg/cm2) -13 -11.7
Elongation at Break % -34.2 -29.1
Angle Tear Strength (Kg/cm) 5.7 13.8
Hardness Shore A 10.0 11.0
[0092] Data recorded in Table 4 depicts that substituting conventionally used synthetic koresin with reclaimed natural rubber as the tackifying agent, displays remarkable difference in quality and wear resistance properties. Sample with compound code 49-1-4 demonstrated comparative specific gravity and mooney viscosity with enhanced rheological properties. It also showed an increase in 300% modulus, tensile strength and elongation at break % as 100 kg/cm2, 189, and 488% respectively. Desirable results were obtained for % change after ageing of the sample, suggesting a longer lifetime of

the sample with compound code 49-1-4 (PCR tread base compound) comprising the reclaimed natural rubber of the present disclosure.
[0093] Table 5 reveals the data recorded for LTR Belt Skim (B7896) and provides for a comparison between properties using koresin and reclaimed natural rubber as tackifying agents.
Table 5

TABLE: 5 R6214
(Koresin -1.25 phr) R2570
Reclaimed natural rubber (NR latex reclaim – 2.5 phr)

B7896 (LTR BELT SKIM)
COMPOUND CODE 49-1-5 [R] 49-1-6 [E]
SAMPLE DETAILS

LTR Belt [R] LTR Belt [E]
Specific gravity 1.195 1.183
ML(1+4)@100oC 71 81
ML UP Mins @125oC 32.2 31.5
RHEO PROPERTY
MH-MH (dN-m) 21.55 20.15
t'-30 (Min) 3.33 3.22
t'-90 (Min) 13.12 11.61
STRESS STRAIN OF CURE D COMPOUND: ORIG INAL
300% Modulus (Kg/cm2) 137 126
Tensile Strength (Kg/cm2) 227 225
Elongation at Break % 475 490
Angle Tear Strength (Kg/cm) 85 73
Hardness Shore A 75 74
STRESS STRAIN OF CURE D COMPOUND: AGED : B1 (80oC * 7 Days
300% Modulus (Kg/cm2) 0 0
Tensile Strength (Kg/cm2) 157 173
Elongation at Break % 188 230
Angle Tear Strength (Kg/cm) 37 41
Hardness Shore A 85 85

% CHANGE AFTER AGEING
300% Modulus (Kg/cm2) -100 -100.0
Tensile Strength (Kg/cm2) -30.8 -22.9
Elongation at Break % -60.4 -53.0
Angle Tear Strength (Kg/cm) -56.7 -44.3
Hardness Shore A -10.1 11.0
OTHER PHYSICALS
STEEL CORD ADHESION OF CURED COMPOUND: ORIGINAL
Pull Out Force (Kg) 54 53
Wire Rubberisation % 90 90
STEEL CORD ADHESION OF CURED COMPOUND: AGED: B1 (80oC * 7 Days)
Pull Out Force (Kg) 54 55
Wire Rubberisation % 85 90
STEEL CORD ADHESION OF CURED COMPOUND: AGED: HMD (aged at high humidity)
Pull Out Force (Kg) 46 52
Wire Rubberisation % 75 75
STEEL CORD ADHESION OF CURED COMPOUND: AGED: SALT AGEING: 8 DAYS
Pull Out Force (Kg) 48 41
Wire Rubberisation % 40 0
[0094] Table 5 demonstrated comparative results between the sample with compound code 49-1-6 comprising 2.5 phr of reclaimed natural rubber and the sample with compound code 49-1-5 comprising 1.25 phr of Koresin for specific gravity, mooney viscosity as well as rheological properties. A remarkable decrease in % change from -60.4% to -53% for elongation at break was observed for the sample with compound code 49-1-6 in comparison to 49-1-5. Further, the sample with compound code 49-1-6 also showed comparable results for steel cord in terms of pull out force and wire rubberisation %. Thus, the compound 49-1-6 of LTR Belt Skim comprising the reclaimed natural rubber of the present disclosure is a more durable and a non-polluting alternative to conventionally used articles comprising synthetic tackifying agents.

[0095] The analysis of the rubber compound of the present disclosure indicated that the reclaimed natural rubber replaced the synthetic resin without affecting the standard rubber compound properties. This proved that the replacement of reclaimed natural rubber can provide a cost-effective rubber compound and the articles made out of the same. The reclaimed natural rubber as a tackifying agent instead of synthetic resin is also environmentally safe in ways such as reuse of waste rubber and replacement of hazardous synthetic chemicals with natural substances.
Advantages of the present disclosure
[0096] The present disclosure is aimed at developing a rubber composition that does not include a synthetic chemical as the tackifying agent. Since the tackifying agent of the present disclosure is a reclaimed natural rubber, it incorporates the benefits of being economically sound and environmentally friendly. The reclaimed natural rubber in the present rubber composition is advantageous in providing improved tack in comparison to synthetic resins being used as tackifying agents. Moreover, incorporating the rubber composition comprising the reclaimed natural rubber in various multi-component articles such as belts and skims does not compromise with their durability and long-term performance. Also, disclosed herein is a convenient and rapid process to obtain the rubber composition of the present disclosure.

I/We Claim:
1) A rubber composition comprising:
(a) one or more rubber;
(b) one or more filler;
(c) one or more additive; and
(d) one or more natural tackifying agent,
wherein the one or more natural tackifying agent is a reclaimed natural rubber.
2) The rubber composition as claimed in claim 1, wherein the one or more natural
tackifying agent has a concentration in the range of 2-8 phr; and the one or
more filler has a concentration in the range of 5-70 phr.
3) The rubber composition as claimed in claim 1, wherein the one or more rubber is selected from the group consisting of natural rubber, polybutadiene rubber, and combinations thereof; and the one or more filler is selected from the group consisting of carbon black N330, carbon black N660, carbon black N326, silica, and combinations thereof.
4) The rubber composition as claimed in claim 1, wherein the reclaimed natural rubber comprises: (a) a natural rubber having a concentration in the range of 75-90 % with respect to the reclaimed rubber; (b) carbon black having a concentration in the range of 4-10% with respect to the reclaimed rubber; (c) ash having a concentration in the range of 7-15% with respect to the reclaimed natural rubber; and (d) acetone extract having a concentration in the range of 0-14% with respect to the reclaimed natural rubber.
5) The rubber composition as claimed in claim 1, wherein the one or more additive is selected from the group consisting of: (a) one or more cross-linking agent; (b) one or more adhesion promoter; (c) one or more activator; (d) one or more antioxidant; (e) one or more accelerator; (f) one or more processing

aid; (g) one or more coupling agent; (h) one or more retarder, and
combinations thereof.
6) The rubber composition as claimed in claim 5, wherein the one or more cross-
linking agent is selected from the group consisting of
hexamethoxymethylmelamine (HMMM), sulphur, and combinations thereof;
the one or more adhesion promoter is selected from the group consisting of
wood resin, resorcinol formaldehyde resin, performance resin, phenol
formaldehyde resin, cobalt salts, and combinations thereof; the one or more
activator is selected from the group consisting of zinc oxide, stearic acid, and
combinations thereof; the one or more antioxidant is 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; the one or more accelerator is
selected from the group consisting N-tert-butyl-2-benzothiazyl sulfonamide
(TBBS), N,N'-dicyclohexyl-2-benzothiazole sulfonamide (DCBS), and
combinations thereof; the one or more processing aid is selected from the
group consisting of zinc based salt of fatty acid, naphthenic oil, p-hydroxy
benzoic acid, and combinations thereof; the one or more coupling agent is
silane, and combinations thereof; and the one or more retarder is N-
(cyclohexylthio) phthalimide (PVI).
7) The rubber composition as claimed in claim 5, wherein the one or more cross-
linking agent has a concentration in the range of 2.0-8.0 phr; the one or more
adhesion promoter has a concentration in the range of 0.2-10.0 phr; the one or
more activator has a concentration in the range of 1.0-10.0 phr; the one or
more antioxidant has a concentration in the range of 0.2-3.0 phr; the one or
more rubber accelerator has a concentration in the range of 0.20-2.0 phr; the
one or more processing aid has a concentration in the range of 0.5-4.0 phr; the

one or more coupling agent has a concentration in the range of 7.0-9.0 phr; and the one or more retarder has a concentration in the range of 0.1-0.3 phr.
8) A process for preparing the rubber composition as claimed in claim 1, said
process comprising:
(a) obtaining one or more rubber;
(b) obtaining one or more filler;
(c) obtaining one or more natural tackifying agent; and
(d) contacting the one or more rubber, the one or more filler, and the one or more natural tackifying agent to the one or more additive, to obtain the rubber composition.
9) The process as claimed in claim 8, wherein contacting the one or more
rubber, the one or more filler, the one or more additive, and the one or more
tackifying agent is done at a temperature in the range of 100-155℃ for a
time period in the range of 5-15 seconds to obtain the composition.
10) An article comprising the rubber composition as claimed in any one of the
claims 1-7.