DESC:Self-Releasing Rubber Grafting Tape Composition and Method of Preparation Thereof

Field of the invention

The present invention relates to biodegradable rubber tape composition and more particularly, to a self-releasing rubber tape designed for grafting and budding of horticultural crops as a part of plant propagation.

Background of the invention

Low density Polyethylene (LDPE) tapes and other similar thermoplastic tapes are widely used for grafting and budding purpose. These tapes are non-biodegradable by its inherent nature and hence pollute the environment. Conventional thermoplastic tapes are also resistant to atmospheric degradation and hence they will not degrade naturally. This leads to physical removal of tapes from the plant after graft maturity and is a labour-intensive process. Further, ultraviolet rays from the atmosphere degrade the rubber tapes during exposure and lead to crack formation on the surface resulting in breakage of the tapes and eventually falling off to the ground. The degradation period of the tapes is usually 30-45 days depending on the outside environment, thereby saving additional manpower required to physically remove tapes after the graft maturity.

Thermoplastic tapes due to its resistance to atmospheric degradation, holds the stem tightly and sometimes “necks” into the stem. This leads to blockage of water and essential nutrients across plant stem. But rubber tapes degrades gradually on exposure to atmosphere and hence losses strength. Here chances of necking into stem will be reduced to a greater extent. The rubber tape being elastic in nature holds the stem with required tightness and thus minimizes the chances of necking.
Conventional thermoplastic tapes do not breathe, i.e., they will not allow transport of moisture and gases from inside the stem to outside. This will lead to moisture collection in and around the grafted areas. This can lead to the fungal and bacterial growth, leading to failure of grafts. However, rubber grafting tapes allow water vapor to escape from the stem thereby ensuring graft areas to be dry and ensure a non-hospitable environment to bacteria and fungi. The moisture impermeability of thermoplastic tapes affects the success of grafting, as thermoplastics are practically impermeable.

Accordingly, there exists a need to provide a biodegradable self-releasing rubber tape that overcome the above mentioned drawbacks of the prior art.

Objects of the invention

An object of the present invention is to provide a rubber grafting tape for grafting and budding of horticultural crops as a part of plant propagation.

Another object of the present invention is to provide tapes that are designed to hold and protect the grafted or budded area of the plant intact until graft union happens.

One another object of the present invention is to provide rubber tapes that are highly elastic to offer a tight and intimate grip on the graft areas where they are wound, allowing the rubber to expand as the plant grows thereby eliminating the chances of ‘necking-in’ into the stem as seen with thermoplastic grafting tapes, where they can be stretched to many times of its length and hence relatively less material is required per graft.

Further object of the present invention is to provide natural degradation of rubber grafting tapes under open atmosphere with the help of heat and UV radiation, to develop cracks, by which its strength is lost and eventually falls off.

Yet another object of the present invention is to provide rubber tapes with selective permeability to air allowing the buds to breathe and preventing moisture to escape thereby providing hydration to the grafted areas.

One another object of the present invention is to improve the grip of tapes imparting a very fine rough surface when the tapes are wound on to the graft area with better thickness uniformity cross the width of the tape leading to a consistent performance.

Summary of the invention

Accordingly, the present invention provides a self-releasing rubber grafting tape composition (hereinafter “the composition”). The composition comprises a natural rubber in a range of 65% by weight to 75 % by weight. Further, the composition comprises a recycled rubber in a range of 5% by weight to 20 % by weight. Furthermore, the composition comprises a styrene butadiene rubber in a range of 5 % by weight to 15 % by weight.

The composition also comprises a first activator in a range of 2 % by weight to 3 % by weight. Further, the composition comprises a second activator in a range of 1% by weight to 2 % by weight. Furthermore, the composition comprises an anti-oxidant in a range of 0 % by weight to 1.5 % by weight. Moreover, the composition comprises an additive in a range of 0.5% by weight to 1.5 % by weight.

The composition also comprises a white filler in a range of 5% by weight to 30% by weight. Further, the composition comprises a carbon black filler in a range of 0% by weight to 20% by weight. Furthermore, the composition comprises a primary accelerator in a range of 0.2% by weight to 2 % by weight. Moreover, the composition comprises a secondary accelerator in a range of 0.2 % by weight to 1 % by weight. The primary and secondary accelerators provide a synergistic curing to the rubber compound. The composition also comprises a curing agent in a range of 1% by weight to 3 % by weight.

In another aspect, the present invention provides a method of preparation of a self-releasing rubber grafting tape.

Brief description of the drawings

Figure 1showsa flowchart of a method of preparation of a self-releasing rubber grafting tape, in accordance with the present invention;

Figure 2 shows the detailed steps of mixing and compounding for preparation of the self-releasing rubber grafting tape, in accordance with the present invention; and

Figure 3 shows a detailed calendering step for preparation of the self-releasing rubber grafting tape, in accordance with the present invention.

Detailed description of the invention

The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.

The present invention provides a self-releasing rubber grafting tape composition and a method of preparation thereof. The rubber tape is used for grafting and budding of horticultural crops as a part of plant propagation. The rubber tapes starts degrading and losing its strength from 30 days onwards when kept in open. Cracks will be observed on the tapes and depending on the atmospheric conditions; they will break and gets shed off from the plant. When the buds grow out, the tapes are penetrated, without breaking it thereby offering continued protection to the graft areas from infection or insect attack. The tape on exposure to the environment degrades naturally and falls off thereby eliminating labor costs on removal of the tapes. Since the tapes are made up of natural ingredients, it will be degraded at a faster rate and gets absorbed into the soil. The main object of the present invention is to provide a portion of natural rubber in the compound to be replaced with a specially regenerated recycled rubber manufactured by special method, mainly to improve the grip of tapes imparting a very fine rough surface when the tapes are wound on to the graft area. The composition and the method of the present invention improves processing of the compound leading to better thickness uniformity across the width of the tape and a consistent performance thatin turn helps in natural degradation of the tapes. The presence of recycled component does not alter the air permeability of tapes.

The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description and in the table below.

Table
Part No Part Name
10 Ingredients
15 Internal Mixer
20 Dump Mill
25 Compound Stack
30 Feed mill
35 4- roll Calendar
36 Talc application
37 Online Gauge
38 Accumulator
39 Winding station

The present invention provides a self-releasing rubber grafting tape composition (herein after, the composition).The composition comprises a natural rubber in a range of 65% by weight to 75 % by weight. Further, the composition comprises a recycled rubber in a range of 5% by weight to 20 % by weight. Furthermore, the composition comprises a styrene butadiene rubber (SBR) in a range of5% by weight to 15 % by weight.

In accordance with the present invention, rubber or diene elastomer is understood to mean an elastomer resulting at least in part (i.e., a homopolymer or a copolymer) from monomers (monomers bearing two double carbon-carbon bonds, whether conjugated or not). In general, essentially unsaturated elastomer is understood here to mean an elastomer resulting at least in part from conjugated monomers, having a content of members or units of SBR origin (conjugated SBR) which is greater than 15% (mol %).

In an embodiment, the composition may contain a single elastomer or a mixture of several elastomers or regenerated elastomers. Specifically, the elastomer or elastomers may be used in association with any type of synthetic elastomer other than the elastomer, or even with polymers other than elastomers, for example thermoplastic polymers.

Further, the composition comprises a first activator in a range of 2 % by weight to 3 % by weight. The first activator is selected from inorganic compounds like metal oxides like zinc oxide, hydrated lime and the like. Furthermore, the composition comprises a second activator in a range of 1% by weightto2 % by weight. The second activator is selected from organic acids like Stearic acid, oleic acid and the like that are used normally in combination with metal oxides.

The composition also comprises an antioxidant in a range of 0 % by weight to 1.5 % by weight. The antioxidant is selected from classes of phenolics that includes monofunctional, bifunctional, multifunctional and bridged phenols, thiobis phenols such as 4.4’-thiobis-6-(t-butyl metacresol), polyphenols like reaction product of butylated p-cresol and dicyclopentadiene, amines such as alkylated diphenyl amines, aromatic phosphites, diphenylamine ketone condensates, napthyl amines such as phenyl-a-napthylamine (PAN), phenyl-ß-napthylamine (PBN), imidazoles, thioesters and dithiocarbamates.

The antioxidants added to the compositions may, for example, be mercaptobenzimidazole (MBI), 2-mercaptomethylbenzimidazole (2-MMBI), 3-mercaptomethylbenzimidazole (3-MMBI), 4-mercaptomethylbenzimidazole (4-MMBI), 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ), nickel dibutyldithiocarbamate (NDBC), 2,6-di-tert-butyl-p-cresol (BHT) and 2,2'-methylenebis(4-methyl-6-tert-butylphenol). These antioxidants may also be used in non-dusting, especially also polymer-bound, supply forms such as ‘microgranules’ or ‘microgranules coated’.

Further, the composition comprises white filler in a range of 5% by weight to 30% by weight. The white filler is selected from calcium carbonate, clays, silicates and titanium dioxide. Furthermore, the composition comprises a carbon black filler in a range of 0% by weight to 20% by weight.

However, it is understood here that any type of fillers known for its capacities to reinforce a rubber composition can be used for the manufacture of tapes, as for example an organic reinforcing filler such as carbon black, an inorganic reinforcing filler such as silica, or else a blend of these two types of filler, more particularly a blend of carbon black and silica. As carbon blacks all carbon blacks are suitable, especially the blacks of types high abrasion furnace (HAF), intermediate super abrasion furnace (ISAF) and super abrasion furnace (SAF) that are conventionally used. Depending on the intended applications, it is also possible to use carbon blacks of higher series Fast-extruding furnace black (FF), fast extruding furnace (FEF), general purpose furnace (GPF) and semi-reinforcing furnace (SRF). The carbon blacks or fillers might, for example, already be incorporated into the diene elastomer, in the form of a master batch, may be added.

The composition also comprises a curing agent in a range of 1% by weight to 3 % by weight. In a preferred embodiment, the curing agent is sulphur. The sulphur used is known variously as pulverized sulphur, rubber maker's sulphur, treated sulphur and commercial sulphur.

Further, the composition comprises a primary accelerator in a range of 0.2% by weight to 2 % by weight. Furthermore, the composition comprises a secondary accelerator in a range of 0.2 % by weight to 1 % by weight. The composition utilizes a combination of the primary and the secondary accelerators to obtain the desired cure rate. The primary and secondary accelerators provide a synergistic curing to the rubber compound. However, it is understood here that a combination of primary, secondary and tertiary accelerators may be used to obtain the desired cure rate in other alternative embodiments of the present invention.

In accordance with the present invention, any compound capable of acting as an accelerator to vulcanization of the diene elastomers in the presence of sulphur, especially thiazole accelerators and derivatives thereof, thiurame accelerators and zinc dithiocarbamate accelerators can be used as the primary or the secondary accelerator. It is preferred to use a sulphenamide primary accelerator. The actual vulcanizing system is based on sulphur (or on a sulphur donor) and on a primary vulcanization accelerator. This base vulcanizing system is supplemented with various known secondary accelerators or vulcanization activators, such as zinc oxide, stearic acid or equivalent compounds, and/or guanidine derivatives (more particularly diphenylguanidine) is incorporated during the mixing process.

In an embodiment, the primary and the secondary accelerators are selected fromthiurams such as tetramethylthiurammonosulphide (TMTM), tetramethylthiuramdisulphide, tetraethylthiuram disulfide (TETD), tetrabenzylthiuram disulfide (TBzTD), xanthates such as zinc isopropyl xanthate (ZIX), sodium isopropyl xanthate (SIX), zinc butyl xanthate (ZBX), dibutylxanthogen disulfide, diethyl xanthogenate, diisopropylxanthogen disulfide, diisobutylxanthogen disulfide, dithiocarbamates such as zinc-N-dimethyl-dithiocarbamate (ZDMC), zinc-N-diethyldithiocarbamate (ZDEC), zinc-N-dibutyl-dithiocarbamate (ZDBC), zinc-N-ethylphenyl-dithiocarbamate (ZEBC), zinc-N-pentamethylenedithiocarbamate (ZPMC), Piperidinepentamethylenedithiocarbamate (PPD), Sodium diethyl dithiocarbamate (SDC), dithiophosphates such as copper diisopropyldithiophosphate, zinc-O-,O-di-n-butyl phosphorodithioate and combinations thereof.

In another embodiment, the primary and the secondary accelerators are selected fromthiazoles2-mercaptobenzothiazole (MBT), zinc or sodium salt of 2-mercaptobenzothiazole (ZMBT), benzothiazyl-2-sulphene morpholide (MBS),benzothiazole disulfide (MBTS),sulphenamides such as benzothiazyl-2-cyclohexyl sulphenamide (CBS), benzothiazoyl-2-tert-butyl sulphenamide (TBBS), benzothiazyldicyclohexy-1 sulphenamide (DCBS),guanidines such as diphenyl guanidine (DPG), Triphenyl guanidine (TPG), diorthotolyl guanidine (DOTG), o-tolylbigaunide (OTBG),thiourea derivatives such as ethylene thiourea (ETU), diethylthiourea (DETU), diphenyl thiourea (DPTU), amine derivatives such as hexamethylenetetramine (HMT), ethylidene aniline (EA) and mixtures thereof.

Further, the composition comprises an additive in a range of 0.5% by weight to 1.5 % by weight. In an embodiment, the additive is selected from plasticizer oils such as aromatic, naphthenic, paraffinic types, low poly cyclic aromatics (PCA) oils, factices, waxes and the like.

In another embodiment, the rubber composition according to the invention may also comprise some or all of the usual additives commonly used in elastomer compositions such as, for example, plasticizers or extender oils, the latter being either aromatic or non-aromatic, pigments, protectants such as anti-ozone waxes, chemical antiozonants, antioxidants (such as 6-paraphenylenediamine), anti-fatigue agents, reinforcing resins, acceptors (for example phenolic novolak resin) or donors of methylene (for example HMT or H3M) and other special ingredients.

The composition according to the invention preferably comprises, as preferred non-aromatic or very slightly aromatic plasticizer, at least one compound selected from the group consisting of naphthenic oils, paraffinic oils, glycerol esters more particularly trioleates, plasticizing hydrocarbon resins and mixtures of such compounds.

The composition is stabilized and strengthened with much better retention of heat aged modulus values, hardness and other related vulcanizate properties. Specifically, a percentage of natural rubber is replaced with recycled rubber to impart favorable properties like surface grip, better processing and the like.

In accordance with the present invention, the composition includes a diene rubber alone or a blend of diene rubbers like natural rubber and sulphur or sulphur donors wherein the composition is stabilized by incorporating antioxidants such as but not limited to an amine or phenolic compounds such as, 4-methyl-phenol, reaction products with dicyclopentadiene and isobutylene, butylated reaction product of p-cresol and dicyclopentadiene and the like.

2-mercaptobenzothiazole (MBT) or sulfenamide derivatives is used as accelerators of vulcanization based on natural rubber or its blends with general purpose synthetic rubbers like styrene butadiene rubber (SBR) and polybutadiene rubber (BR) using sulphur as a cross linking agent and zinc oxide and stearic acid are used as cure activators.
The base rubber offers a continuous rubber matrix to the product whereas other ingredients like curing agent and accelerators improve the physical properties of the tape. Further, the antioxidants and waxes improve the aging resistance of the tape while white and black fillers improve the physical properties and processibility of the rubber compound. The post treatment with any one of hydrated magnesium silicate and magnesium silicate powder is done to avoid sticking of sheets and to prevent clumping together of the tapes while on storage.

In another embodiment, the composition also includes ageing stabilizers, for example in the form of discolouring ageing stabilizers with antiozone action, for example N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N-1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine (6PPD), N-1,4-dimethylpentyl-N'-phenyl-p-phenylenediamine (7PPD), N,N'-bis-(1,4-dimethylpentyl)-p-phenylenediamine (77PD), discolouring ageing stabilizers with fatigue protection but no antiozone action such as phenyl- alpha-naphthylamine (PAN), discolouring ageing stabilizers with low antifatigue action and no antiozone action such as octylated diphenylamine (ODPA), non-discolouring ageing stabilizers with fatigue protection and good heat protection such as styrenized phenols (SPH), non-discolouring ozone stabilizers with no anti-ageing action such as waxes or mixtures of specific hydrocarbons, cyclic acetals and enol ethers, and hydrolysis stabilizers such as polycarbodiimides.

In yet another embodiment, vulcanization retarders may be added to the compositions like sulphonamides, sulphanilides or phthalimides. Suitable examples of the vulcanization retarders are N-trichloromethylsulphenyl benzenesulphanilide, N-cyclohexylthiophthalimide, phthalic anhydride (PTA), salicylic acid (SAL), N-nitrosodiphenylamine (NDPA), trichloromelamine (TCM), maleic anhydride (MSA) and N-trichloromethylsulphenyl benzenesulphanilide.

In yet another embodiment, when chemical crosslinking is performed by means of one or more peroxide compounds, the peroxide compound or compounds represent from 0.01 to 10 phr. Peroxide compounds which can be used as a chemical crosslinking system include acyl peroxides, for example benzoyl peroxide or p-chlorobenzoyl peroxide, ketone peroxides, for example methyl ethyl ketone peroxide, peroxyesters, for example t-butyl peroxyacetate, t-butyl peroxybenzoate and t-butyl peroxyphthalate, alkyl peroxides, for example dicumyl peroxide, di-t-butyl peroxybenzoate and 1,3-bis(t-butyl peroxyisopropyl)benzene and hydroperoxides, for example t-butyl hydroperoxide.

Now referring to figures 1 to 3, a method (200)of preparation ofa self-releasing rubber grafting tape in accordance with the present invention is shown. Specifically, the self-releasing rubber grafting tape is prepared using the composition of the present invention. The self-releasing rubber grafting tapeis made out of the composition based on at least one diene elastomer, a reinforcing filler, a chemical cross-linker, a cross linking accelerator and an antioxidant.

The rubber composition according to the invention is manufactured in suitable mixers, using two successive preparation phases according to a general procedure which is well known to the skilled person: a first phase of thermo mechanical working or kneading (sometimes termed "non-production" phase) at high temperature, up to a maximum temperature of between 100 degree C and 180 degree C, preferably between 105 degree C and 135 degree C, followed by a second phase of mechanical working (sometimes termed "productive" phase) at a lower temperature, typically of less than 120 degree C., for example between 60 degree C and 100 degree C, a finishing phase during which the chemical cross linking system is incorporated.

Generally, all of the base constituents of the composition of the present invention, with the exception of the chemical cross linking system, these being the reinforcing filler or fillers and the plasticisers where appropriate, are incorporated intimately by kneading, into the diene elastomer or diene elastomers during the first, non-productive phase, in other words, at least these various base constituents are introduced into the mixer and kneaded thermo mechanically, in one or more steps, until the maximum temperature of between 100 degree C and 180 degree C., preferably between 105 degree C. and 135 degree C, is reached.

Again referring to figures 1-3, the method (200) at first step involves loading of all ingredients (10) into an internal mixer (15) and mixing of all the ingredients (10) at step two. The ingredients (10) includes a predefined quantities of the natural rubber, the recycled rubber, the styrene butadiene rubber, the first activator, the second activator, the antioxidant, the additive, the white filler, the carbon black, the primary accelerator, the secondary accelerator and the curing agent. The internal mixer (15) is used to mix, blend and incorporate rubber and its consistent chemicals and oils to form a rubber compound. This rubber compound is used as an input material for subsequent rubber process.

In a next step, the method involves subjecting the mixture to compounding process through a dump mill (20) and stacking up for further processing. Once sufficient quality of mixing is ensured at the internal mixer (15), the compound is discharged to an open two roll mill that is placed below the mixer door. Once the mixing is done, the compound is cut out from mill in the form of sheets and stacked (25) on a pallet for maturation and for subsequent processing. Thereafter, the rubber compound feed into a feed mill (30). The feed mill (30) is a two roll mill that warms and conditions the rubber compound and this compound is used to feed calendar nip.

In a next step, the method (200) involves calendering the mixture to form a continuous sheet. Specifically, the well mixed rubber compound is fed into a4-roll calendar (35) to form thin continuous sheets of a predefined thickness and width. The 4-roll calendar(35) is equipped with a special arrangement of layering up of sheets to give a defect-free output.
In a next step, the method involves curing of the formed continuous rubber sheet and slitting the cured sheet for making in the form of a tape. The sheets are cured in specially designed, process specific curing chamber. The sheets prepared tend to stick each other and hence powdery materials like talc need to be applied to prevent sheets sticking together. The cured sheet is subjected to a post treatment with materials like magnesium silicate powder (36) to prevent sticking of clumping together while storage of tapes.

In a next step, the method involves checking quality and dimension of the tape for packaging purpose. An online gauge (37) is a noncontact measuring instrument that is used to measure the quality of rubber sheets like thickness, on a continual basis. An accumulator (38) is composed of a set of rolls that accumulates and supply sheets to downstream processing thereby ensuring continuous supply of sheets to downstream processes. A winding station (39) positioned at the end of the line is used for winding and collecting sheets to further processing.

In accordance with the present invention, the tape formed is a flexible tape of specified dimensions designed to wind around plant stems to provide a tight seal around the grafted or budded areas and lock it firmly over a specified period of time.

The tape is designed to cover and protect the grafted areas for a specified time till the graft heals and thereafter degrades by itself as a result of natural aging process. The degradation happens by formation of cracks on the tapes surface due to environment exposure. The cracks eventually lead to breakage of tapes and it falls off to the ground. The rubber tapes are made up of naturally degrading materials and hence the fallen tape eventually degrades and mixes up with soil.

The invention is further illustrated hereinafter by means of examples.

Example 1: Preparation of self-releasing rubber grafting tape composition
The following table provides list of ingredients and their quantity used for the preparation of the self-releasing rubber grafting tape composition
Sr. No. Ingredients Phr
1 Natural Rubber 75-85
2 Recycled Rubber 5-15
3 SBR 1502 5-15
4 ZnO 2-3
5 Stearic Acid 1-2
6 Wingstay L 0-1
7 Paraffin Wax 0.5-1.5
8 DOTG 0.2-0.8
9 MBT 0.2-0.8
10 MBTS 0.2-0.8
11 Sulphur 1-2
Total 100

Advantages of the invention:

1. The composition provides a cost effective self-releasing rubber grafting tape that is biodegradable under open atmosphere with the help of heat and UV radiation.
2. The composition and the method provide tapes of low modulus and stretchable nature of rubber that is designed to hold and protect the grafted or budded area of the plant intact until graft union happens.
3. The self-releasing graft tape provides elasticity that is stretchable many times of its length and eliminates the chances of ‘necking-in’ into the stem as seen with thermoplastic grafting tapes.
4. The composition and the method provide rubber tapes with selective permeability to air allowing the buds to breathe while preventing moisture to escape thereby providing de-hydration to the grafted areas.
5. The method allows the use of regenerated rubber manufactured at a lower temperature than conventional recycled rubber that is also beneficial from the point of environment.
6. The present invention provides rubber tapes in different colours to be suitable to different environment.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the scope of the present invention.
,CLAIMS:We Claim:

1. A self-releasing rubber grafting tape composition comprising:
? a natural rubber in a range of 65% by weight to 75 % by weight;
? a recycled rubber in a range of 5% by weight to 20 % by weight.
? a styrene butadiene rubber in a range of5% by weight to 15 % by weight;
? a first activator in a range of 2 % by weight to 3 % by weight;
? a second activator in a range of 1% by weight to 2 % by weight;
? an antioxidant in a range of 0 % by weight to 1.5 % by weight;
? an additive in a range of 0.5% by weight to 1.5 % by weight;
? a white filler in a range of 5% by weight to 30% by weight;
? a carbon black filler in a range of 0% by weight to 20% by weight;
? a primary accelerator in a range of 0.2% by weight to 2 % by weight;
? a secondary accelerator in a range of 0.2% by weight to 1 % by weight; and
? a curing agent in a range of 1% by weightto3 % by weight.

2. The self-releasing rubber grafting tape composition as claimed in claim 1, wherein the first activator is selected from inorganic compounds like metal oxides like zinc oxide, hydrated lime and the like.
3. The self-releasing rubber grafting tape composition as claimed in claim 1, wherein the second activator is selected from organic acids like stearic acid, oleic acid and the like.

4. The self-releasing rubber grafting tape composition as claimed in claim 1, wherein the antioxidant is selected from classes of phenolics that includes monofunctional, bifunctional, multifunctional and bridged phenols, thiobis phenols such as 4.4’-thiobis-6-(t-butyl metacresol), polyphenols like reaction product of butylated p-cresol and dicyclopentadiene, amines such as alkylated diphenyl amines, aromatic phosphites, diphenylamine ketone condensates, napthyl amines such as phenyl-a-napthylamine, phenyl-ß-napthylamine, imidazoles, thioesters and dithiocarbamates.

5. The self-releasing rubber grafting tape composition as claimed in claim 1, wherein the white filler is selected from calcium carbonate, clays, silicates and titanium dioxide.

6. The self-releasing rubber grafting tape composition as claimed in claim 1, wherein the primary and the secondary accelerators are selected from thiurams such as tetramethylthiurammonosulphide, tetramethylthiuramdisulphide, tetraethylthiuram disulfide, tetrabenzylthiuram disulfide, xanthates such as zinc isopropyl xanthate, sodium isopropyl xanthate, zinc butyl xanthate, dibutylxanthogen disulfide, diethyl xanthogenate, diisopropylxanthogen disulfide, diisobutylxanthogen disulfide, dithiocarbamates such as zinc-N-dimethyl-dithiocarbamate, zinc-N-diethyldithiocarbamate, zinc-N-dibutyl-dithiocarbamate, zinc-N-ethylphenyl-dithiocarbamate, zinc-N-pentamethylene dithiocarbamate, Piperidine pentamethylenedithiocarbamate, Sodium diethyl dithiocarbamate, dithiophosphates such as copper diisopropyldithiophosphate, zinc-O-,O-di-n-butylphosphorodithioate and combinations thereof.

7. The self-releasing rubber grafting tape composition as claimed in claim 1, wherein the primary and the secondary accelerators are selected from thiazoles such as 2-mercaptobenzothiazole, zinc or sodium salt of 2-mercaptobenzothiazole, benzothiazyl-2-sulphene morpholide, benzothiazole disulfide, sulphenamides such as benzothiazyl-2-cyclohexyl sulphenamide, benzothiazoyl-2-tert-butyl sulphenamide, benzothiazyldicyclohexy-1 sulphenamide, guanidines such as diphenyl guanidine, triphenyl guanidine, diorthotolyl guanidine, o-tolylbigaunide, thiourea derivatives such as ethylene thiourea, diethylthiourea, diphenyl thiourea, amine derivatives such as hexamethylenetetramine, ethylidene aniline and mixtures thereof.

8. The self-releasing rubber grafting tape composition as claimed in claim 1, wherein the additive is selected from oils such as aromatic, naphthenic, paraffinic types, low poly cyclic aromatics (PCA) oils, factices and waxes.

9. The self-releasing rubber grafting tape composition as claimed in claim 1, wherein the curing agent is sulfur.

10. A method of preparation of a self-releasing rubber grafting tape, the method comprising the steps of:
• loading of all ingredients (10) into an internal mixer (15) and mixing of all the ingredients (10), wherein the ingredients (10) includes a predefined quantities of a natural rubber, recycled rubber, a styrene butadiene rubber, a first activator, a second activator, an antioxidant, an additive, a white filler, a carbon black, a primary accelerator, a secondary accelerator and a curing agent;
• subjecting the mixture to compounding process through a dump mill (20) and stacking up for further processing;
• calendering the mixture into a 4-roll calendar (35) to form a continuous sheet;
• curing of the formed continuous rubber sheet and slitting the cured sheet for making in the form of a tape;
• applying talk to the tape; and
• checking quality and dimension of the tape for packaging purpose.

Dated this on 06thMarch 2019

Prafulla Wange
(Agent for Applicant)
(IN/PA/2058)