Device and method for separating the sealing from a self-sealing tire

Abstract

A method and apparatus for recycling self-sealing tires and recycling the constituent products resulting from the former recycling process. The tires in question comprise a tire tread having an inner surface and an outer surface and a puncture-resistant layer of silicone self-sealing tire sealant applied on the inner surface, wherein the puncture-resistant layer of silicone self-sealing tire sealant is usually a layer of condensation cured self-sealing tire silicone sealant.

Description

[0001]SELF-SEALING TIRES The present disclosure relates to a method and apparatus for recycling self-sealing tires and recycling the constituent products resulting from the former recycling process. The tires in question comprise a tire tread having an inner surface and an outer surface and a puncture-resistant layer of silicone self-sealing tire sealant applied on the inner surface, wherein the puncture-resistant layer of silicone self-sealing tire sealant is usually a layer of condensation cured self-sealing tire silicone sealant. Globally it is believed up to a billion or even more vehicle tires come to the end of their functional life each year and need to be disposed of. They are referred to as “end-of-life tires” or ELTs as they are deemed to be no longer able to serve their intended purpose on a vehicle. In many countries a large proportion of ELTs end up in landfill which is a significant problem because they both take up a large amount of landfill space and have a significantly negative environmental impact on the surrounding area. If left such tires will decompose very slowly releasing harmful chemicals into the surrounding environment and obviously are not aesthetically pleasing, especially if left in huge piles. They can catch fire in which case clouds of toxic fumes incorporating carcinogens and mutagens and other toxins such as butadiene and / or styrene combustion products as well as dioxins, furans, cyanides, carbon monoxide and / or sulphur dioxide can be released. Furthermore, in some cases heavy metals such as lead, mercury and / or chromium (VI) can also be released from burning tires. To complicate matters further modern-day tires are not made solely from rubber(s) but tire components such as treads, belt packages, carcass layers and side walls can incorporate fibres, textiles and particularly steel wires as means of reinforcement. A variety of methods for recycling tires have been proposed. In many or most of these the first step is the removal of steel wires when present. After this the tires may undergo a wide range of processes. These may include: various tire shredding and grinding processes, cryogenic crushing (where tires are frozen to a temperature of about -50 to -80oC to render the rubber brittle so that the tires can be crushed); pyrolysis i.e., the thermal degradation of the organic components of the tires, typically at pyrolysis temperatures of up to and around e.g., 500 °C to produce an oil, gas and char product in addition to the recovery of the steel (if not removed prior to pyrolysis); as well as other processes including, for example, the process described in US6722593. Of these probably the shredding and grinding processes are the cheapest and most commonly utilised. However, the introduction of self-sealing tires (SSTs) has created issues for such processes. Self- sealing tires (SSTs) have been introduced to allow a vehicle to continue to travel after a puncture or the like in one or more tires by sealing the puncture and preventing the loss of pressure. This makes it possible, for example, to drive to a breakdown point without having to stop, often in hazardous circumstances, to fit a spare tire. Self-sealing tire (SST) technology has become an increasingly important route to achieve safe and sustainable mobility. SSTs contain an inner layer of a self- sealing material e.g., a sealant which by definition is capable of automatically ensuring that a tire is sealed in the event of a puncture thereof by a foreign body, such as a nail. To be usable, a self-sealing layer made upon cure from a suitable self-sealing composition must be effective over a very wide range of operating temperatures and to do so over the entire lifetime of the tire. It must be capable of closing off holes when the responsible puncturing object, which we call a “nail”, remains in place. Upon expelling the nail, the self-sealing layer must be able to fill up the hole and make the tire airtight, especially under winter conditions. Until recently, most SSTs used butyl rubber sealants and the like were applied as the puncture- resistant layer of silicone self-sealing tire sealant, to seal the puncture. However, butyl rubber-based materials are cured / vulcanized onto the inner surface (tread) of the tire tread using a radical curing process, which imparts chemical bonding between the butyl rubber and the inner surface (tread) of the tire tread. Currently therefore, self-sealing tires are mostly considered non-recyclable today as recycling processes of SSTs coated with butyl / synthetic rubber blend sealants have several limitations not least if they are to be included in mechanical shredding operations: (i) They require labor-intensive sorting to separate SSTs from conventional tires prior to mechanical shredding; and (ii) Mechanical shredding can only accommodate about 10 % of SSTs at any one time when otherwise fed with conventional otherwise, problems, such as “gumming up” shredder and sticking to shaking sieve, occur due to the formation of large “soccer balls”. This is because the butyl sealants are exceptionally difficult to remove from an end-of-life tire (ELT) because they are too strongly chemically bound to the tire tread / inner surface on which they were applied as a puncture-resistant layer. Other problems which are known to happen when trying to recycle tires with butyl layer self-sealing tire sealant as puncture-resistant layers is sticking of the butyl sealants to conveyors used during the separation process due to the highly tacky butyl / synthetic rubber coating especially at elevated temperatures generated during shredding. Hence, as the sales of self-sealing tires grow there is a consequential increase in waste butyl rubber SSTs being sent to landfill as the means of disposal, especially those having butyl / synthetic rubber blend sealants as puncture-resistant layers because of the inability to separate the butyl / synthetic rubber blend sealant puncture-resistant layers from the tire treads. Whilst some suggestions have been proposed they largely fail to describe how the butyl rubber is separated from the tire tread in practical manner. The recent introduction of self-sealing tires using cured silicone self-sealing tire sealants as puncture-resistant layers has resulted in a more practical opportunity to recycle such self-sealing tires as unlike the butyl rubber self-sealing layers attached to tire tread such cured silicone sealants are more easily separable therefrom at end-of-life. The use of a suitable condensation cured self-sealing tire silicone sealant as the puncture-resistant layer applied on the inner surface of the tire tread in an SST imparts a good physical adhesion to the rubber but the condensation cured self-sealing tire silicone sealants used are not chemically bound to the inner surface of the tire tread (tread) because the condensation cured self-sealing tire silicone sealant does not induce any form of chemical bonding reaction with the rubber of inner surface (tread) of the tire tread. They do, however, exhibit a suitably high tackiness e.g., they are very sticky / tacky to the touch after application to the inner surface of a tire tread as a puncture-resistant layer of silicone self-sealing tire sealant and exhibit good wetting properties and excellent physical adhesion to the rubber. As identified in PCT / US2023 / 034873, despite its tackiness such condensation cured silicone sealant can be separated from the inner surface of the tire tread (tread) by either:- ai) removing the layer of condensation cured self-sealing silicone sealant by scraping off the inner surface of the tire tread with a suitable scraper or aii) making a cut in the layer of condensation cured self-sealing silicone sealant, to form a first and second end thereof, attaching the first end of condensation cured self-sealing silicone sealant to a roller and peeling said condensation cured self-sealing silicone sealant from the inner surface of the tire tread. In the present disclosure there is provided a self-sealing tire recycling apparatus comprising the following components: (i) an optional support, (ii) a tire spreading means; (iii) a self-sealing tire sealant removal apparatus in the form of a roller, mandrel or screw adapted to receive precut sealant attached to it before continuously peeling off a layer of a silicone self-sealing tire sealant from a self-sealing tire optionally in combination with a suitable nozzle designed to remove the layer of silicone self-sealing tire sealant from a self-sealing tire by way of directing pressurized fluids at the layer of silicone self-sealing tire sealant having a means of controlling the dimensions thereof so as to be adaptable to fit the dimensions of a layer of silicone self-sealing tire sealant in a self-sealing tire to enable removal in a single operation; (iv) a means of rotating the self-sealing tire sealant removal apparatus relative to a stationary tire; and optionally (v) an element for collecting removed silicone self-sealing tire sealant from a self-sealing tire comprising at least one of (a’) a container with one side open or a moving conveyor belt to receive the removed sealant; and (b’) a vacuum sucking device. There is also provided a method of recycling self-sealing tires with the self-sealing tire recycling apparatus described herein by taking a self-sealing tire which comprises a tread having an inner and outer surface and sidewalls on opposite sides of said tread which sidewalls are spaced apart at a regular spacing and which has a layer of silicone self-sealing tire sealant on the inner surface of the tread; optionally placing said self-sealing tire on or in support (i), attaching a tire spreading means (ii) having tire engaging elements which engage the sidewalls on the opposite sides of the tire tread and transfer and fix said sidewalls in a spread position in which the tire sidewalls are spaced further apart than their regular spacing; inserting the self-sealing tire sealant removal apparatus having a means of controlling the dimensions thereof (iii) into the tire and adjusting same to fit the dimensions of the layer of silicone self-sealing tire sealant; using the means of rotating self-sealing tire sealant removal apparatus relative to a stationary tire means (iv) to rotate the self-sealing tire sealant removal apparatus (iii) relative to a stationary tire to remove the layer of silicone self-sealing tire sealant from the inner surface of the tread; and collecting the removed silicone self-sealing tire sealant optionally with (v) the element for collecting removed silicone self-sealing tire sealant from a self-sealing tire comprising at least one of (a’) a container with one side open or a moving conveyor belt to receive the removed sealant; and (b’) a vacuum sucking device. There is also provided a use of a self-sealing tire which comprises a tread having an inner and outer surface and sidewalls on opposite sides of said tread which sidewalls are spaced apart at a regular spacing and which has a layer of silicone self-sealing tire sealant on the inner surface of the tread; which layer of silicone self-sealing tire sealant has at least one of :- a coating overlap in the layer of silicone self-sealing tire sealant, a liner applied to the layer of silicone self-sealing tire sealant; and a luminescence agent in or on the layer of silicone self-sealing tire sealant; to assist in the removal of the layer of silicone self-sealing tire sealant from the inner surface of the tire tread in a method of recycling self-sealing tires as described herein. There is also provided recycled rubber and recycled silicone sealant obtained as products of the method described herein from a self-sealing tire. The Self-sealing tire recycling apparatus The self-sealing tire recycling apparatus described herein comprises components (ii), (iii) and (iv) and optionally support (i) and / or component (v). The optional support (i) of the self-sealing tire recycling apparatus described herein may be a solid support on which the tire is rested whilst it is being engaged with the remainder of the apparatus, in particular tire spreading means (ii) for removing the layer of silicone self-sealing tire sealant. When present, the support (i) may form part of tire spreading means (ii) or be engageable or lockable with the tire spreading means (ii) described below. In use optional support (i) may support the tire when standing vertically or positioned horizontally. It is typically relied upon as a means for resting the tire during before or after the process for removing the layer of silicone self-sealing tire sealant. The tire spreading means (ii) of the self-sealing tire recycling apparatus described herein may be a tire spreader or a series of clamps or the like designed to spread apart sidewalls of a tire when the tire is not installed on a wheel rim in order to improve access to the inside of the tread of the self- sealing tire. As previously discussed, the self-sealing tire comprises a tread having an inner and outer surface and sidewalls on opposite sides of said tread which sidewalls are spaced apart at a regular spacing and which has a layer of silicone self-sealing tire sealant on the inner surface of the tread. When a tire spreader is used for the method herein, the tire spreader is adapted to engage each of the sidewalls of the self-sealing tire with the inner surface of the tread having a of silicone self- sealing tire sealant on the inner side of the tread. The tire spreader has tire engaging elements which engage the sidewalls on the opposite sides of the tire tread. The engaging elements are designed so as to be able to transfer and fix said sidewalls from a normal position at their intended regular spacing to a spread position in which the tire sidewalls are spaced further apart than their regular spacing. In one embodiment, for the sake of example, the tire spreader comprises a first tire engaging element and a second tire engaging element for contacting a respective one of the sidewalls; the first and second tire engaging elements being pivotally connected to a base or one another at a (respective) coupling location so that the tire engaging elements can pivot relative to the support (i) when present, and / or one another from the normal position, in which the sidewalls are spaced apart at a regular spacing, to a spread position in which the tire engaging elements are spaced further apart than in the neutral position so as to spread the engaged sidewalls further apart from their normal. An actuator is used to cause the engaging elements to move in opposite directions to spread the sidewalls apart and once the engaging elements have reached their position to place the tire sidewalls in the spread position they are locked in place for as long as is desired. Any suitable tire spreader may be utilised for this purpose, for example, for example one where the user fixes the tire to a support and then opening the tire in the lateral / width direction or commercial tire spreaders such as a 5700 Tire Spreader from Branick Industries Inc. of North Dakota USA, which may be used for rotating the self-sealing tire (SST) while the layer of silicone self-sealing tire sealant is being removed from the inner surface of the tread. In one embodiment, support (i) may be an integral part of tire spreading means (ii). The self-sealing tire sealant removal apparatus (iii) The self-sealing tire sealant removal apparatus (iii) as described herein is a roller, mandrel or screw, alternatively a roller or mandrel, alternatively a roller, adapted to receive precut sealant attached to it before continuously peeling off sealant from a self-sealing tire optionally in combination with a suitable nozzle designed to remove the layer of silicone self-sealing tire sealant from a self-sealing tire by way of directing pressurized fluids at the layer of silicone self-sealing tire sealant. The self-sealing tire sealant removal apparatus (iii) is designed for peeling a layer of silicone self- sealing tire sealant from the surface of the SST. It may comprise a roller, mandrel or screw, adapted to receive precut sealant attached to it before continuously peeling off the layer of silicone self- sealing tire sealant from the self-sealing tire. Typically, sealant from the layer of silicone self-sealing tire sealant being removed is precut and then physically attached or engaged to the roller, mandrel or screw. Any suitable means for achieving this may be utilised, i.e., the roller, mandrel or screw may contain a hook, a slot, a clamping means or a series of projecting spikes or the like to engage the sealant for easier sealant attachment and removal. The roller, mandrel or screw apparatus also has a means adapted to be receive precut sealant attached to it before component (iv) of the apparatus is utilised to rotate the said roller, mandrel or screw in order to continuously peel off sealant from the self-sealing tire to which the apparatus is engaged. In this instance, the apparatus is probably most suited to be used alone when the layer of silicone self-sealing tire sealant (typically condensation cured self-sealing tire silicone sealant) to be removed is not overly sticky / tacky to the touch and / or has a larger tensile strength to allow smooth peeling without tensile breakage of the sealant during peeling, as no nozzle designed to remove the layer of silicone self-sealing tire sealant from a self-sealing tire by way of directing pressurized fluids at the layer of silicone self-sealing tire sealant is required. Optionally when the self-sealing tire silicone sealant to be removed is very sticky / tacky to the touch the nozzle may be additionally used to assist in smooth peeling without tensile breakage of the sealant during the peeling process. If desired a vibration mechanism such as an air-scraper may be incorporated on the roller, mandrel or screw to induce vibration and / or oscillation in the peel angle to help peeling the condensation cured self-sealing tire silicone sealant from the inner surface of the tire tread. Furthermore, if desired the or each roller, mandrel or screw may be designed to move from a sharp angle to a less sharp peeling angle as and when desired in order to improve efficiency of the system. Alternatively, the or each roller, mandrel or screw may be designed to move back and forth in the direction of the collected product in order to induce extension forces that improve the efficiency of collecting the silicone sealant product. The roller, mandrel or screw of the self-sealing tire sealant removal apparatus (iii) type (iii)(a) is adapted to be engaged with precut sealant attached to it before continuously peeling off sealant from a self-sealing tire. In one embodiment the precut sealant on the inner surface of the tire may comprise a coating overlap in the layer of silicone self-sealing tire sealant to ease engagement of the cut sealant to the roller, mandrel or screw of the self-sealing tire sealant removal apparatus (iii) prior to the commencement of the process removing the layer of silicone self-sealing tire sealant. In a preferred embodiment the tire is held rigid on support (i), when present, or by the tire spreading means (ii) and the or each roller, mandrel or screw is rotated to peel the layer of silicone self-sealing tire sealant away from the inner surface of the tire tread after the layer has been cut and attached to the roller, mandrel or screw. Optionally the said type (iii) apparatus may comprise a second element such as a second roller or a plate for controlling the peeling angle at which the layer of silicone self-sealing tire sealant is removed. The peeling angle is defined as the angle between the surface on the tire tread (substrate) from which the sealant is being removed and the plane of the sealant being transferred to the roller, mandrel or screw subsequent to peeling. Otherwise, the roller, mandrel or screw can function as a peeling angle control element as well as sealant collecting element. The peeling angle may also be about 1° and about 90°, alternatively from about 5° to about 80°, alternatively from about 5° and about 70°, alternatively from about 10 ° to about 60°. In another embodiment the layer of silicone self-sealing tire sealant on the inner surface of the tire tread may comprise an inner liner to aid peeling the sealant from the tire without breaking the sealant. When present the liner can be applied onto the layer of silicone self-sealing tire sealant once it has cured in place on the tire tread or it may be applied onto the layer of silicone self-sealing tire sealant prior to removal of said layer of silicone self-sealing tire sealant from the inner surface of the tire tread at end of life of the tire. The presence of such a liner is designed to assist in ensuring as much of the layer of silicone self-sealing tire sealant is removed in a single rotation as possible. Preferably the liner is a release liner such that once the layer of silicone self-sealing tire sealant has been removed from the inner surface of the tire tread the layer of silicone self-sealing tire sealant and liner can be easily separated or alternatively that the liner may be recycled together with the layer of silicone self-sealing tire sealant subsequent to its removal. In a still further embodiment, a fluorophore (luminescence) agent may be provided in the layer of silicone self-sealing tire sealant, alternatively may be included in the tire itself to identify a self- sealing or may be painted on the layer of silicone self-sealing tire sealant prior to removal thereof from the inner surface of the tire tread such that it will be easier to see any remaining parts of the layer of silicone self-sealing tire sealant which was not wholly removed from the tire tread. Preferably the fluorophore is a photoluminescent agent, i.e., a fluorescent agent or a phosphorescent agent. Any suitable photoluminescent agent may be used for example fluorescent dyes such as derivatives of xanthene (fluorescein), cyanine, squaraine, naphthalene, coumarin, anthracene and other fluorescent dyes including commercial fluorescent dyes such as members of the Alexa FluorTMfamily of fluorescent dyes commercially available from Thermo Fisher Scientific. Optionally, the self-sealing tire sealant removal apparatus (iii) may additionally utilise a suitable nozzle designed to remove the layer of silicone self-sealing tire sealant from a self-sealing tire by way of directing pressurized fluids such as air or water or other chemical fluids delivered by a nozzle with special shapes to the sealant-tire interface to enable easier sealant removal. Any suitable apparatus may be utilised, for example Flow Waterjet products from Flow International Corporation of California USA. The adhesiveness of the condensation cured self-sealing tire silicone sealant enables newly collected sealant having been separated from the inner surface of the tire tread to stick to the already collected sealant at the interfacial surfaces, to simplify the collecting operation, particularly when relying on the aforementioned roller / mandrel / screw. In one embodiment the roller, mandrel or screw utilised to collect the separated condensation cured self-sealing tire silicone sealant Means of controlling the dimensions of the self-sealing tire recycling apparatus (iii) The means of controlling the dimensions of the self-sealing tire recycling apparatus (iii) described herein is provided such that the apparatus can be adapted to fit the dimensions of a layer of silicone self-sealing tire sealant in a self-sealing tire so that the layer of silicone self-sealing tire sealant in the self-sealing tire may be removed in a single operation. It may be an element for adjusting the height of the sealant removing element (iii) to accommodate different tire diameters and / or an element for adjusting the width of the sealant removing element (iii) to accommodate different tire. The intention for these elements is to ensure that a single apparatus can be utilised to remove the silicone layer within a standard range of tire widths, preferably in a single rotation of the tire when the sealant removing element (iii) is fixed and the tire is rotated. However, preferably the tire is fixed in position and the sealant removing element (iii) is designed to move. The intention for these elements is to ensure that a single apparatus can be utilised to remove the silicone layer within a standard range of tire widths, preferably in a single rotation of the tire when the sealant removing element (iii) is fixed and the tire is rotated or vice versa with the latter alternative preferred. Means of rotation Apparatus (iv) The means of rotating the self-sealing tire sealant removal apparatus (iii) relative to a stationary tire (iv) may be a motor or actuator designed to rotate the self-sealing tire sealant removal apparatus (iii) while the other of said tire is stationary and thereby enable self-sealing tire sealant removal apparatus (iii) to remove the sealant from the tire tread. The self-sealing tire sealant removal apparatus (iii) is a roller, mandrel or screw and the layer of silicone self-sealing tire sealant on the inner surface of the tread of the self-sealing tire is being removed by peeling with a roller, mandrel or screw rotation speed which may be automatically adjusted to prevent breakage of the peeled off material based on the tensile strength of the silicone sealant. For example, a sensor such as a torque sensor or load cell, that can detect the force tangential to the circumference of the roller, mandrel or screw, may be adapted to adjust speed to prevent breakage of the sealant being removed from the tire. In one embodiment a sensor such as a torque sensor or load cell may be utilised to detect the force tangential to the circumference of the roller, mandrel or screw and to control / adjust roller, mandrel or screw speeds to prevent breakage of the sealant being removed from the tire. The tire is fixed in position using a tire spreader, e.g., to the support (i) when present or tire spreader (ii) and self-sealing tire sealant removal apparatus (iii) is rotated by any suitable means e.g., a motor or actuator, an example being an electric drill or the like may be used. In the above embodiments the tire is supported in a vertical position by support (i) when present and / or tire spreader (ii). In a further embodiment in a semi-automated or fully automated embodiment can be designed with the tire supported horizontally by support (i) when present and / or tire spreader (ii). In such an embodiment support (i) may be a tire conveyor belt in a tire recycling facility to remove layer of silicone self-sealing tire sealant from successive tires continuously. Element for collecting removed silicone self-sealing tire sealant (v) The element for collecting the removed layer of silicone self-sealing tire sealant from a self-sealing tire (v) is optional, typically used when the roller, mandrel or screw is not being used for collection. Element (v) when present is either (a’) a container with one side open or a moving conveyor belt to receive the removed sealant; and / or (b’) a vacuum sucking device. In one embodiment the tire may be held in a vertical position during removal of the layer of silicone self-sealing tire sealant. Alternatively, the tire may be held in a horizontal position during removal of the layer of silicone self-sealing tire sealant. The apparatus (i) (when present) and (ii) – (v) are consequently positioned accordingly to accommodate removal of the layer of silicone self-sealing tire sealant whichever position of the tire. Method of recycling self-sealing tires The method of recycling self-sealing tires with the apparatus described above involves removing the layer of silicone self-sealing tire sealant from the self-sealing tire. This is achieved by taking a self- sealing tire which comprises a tread having an inner and outer surface and sidewalls on opposite sides of said tread which sidewalls are spaced apart at a regular spacing and which has a layer of silicone self-sealing tire sealant on the inner surface of the tread; optionally placing said self-sealing tire on or in support (i), attaching a tire spreading means (ii) having tire engaging elements which engage the sidewalls on the opposite sides of the tire tread and transfer and fix said sidewalls in a spread position in which the tire sidewalls are spaced further apart than their regular spacing; inserting the self-sealing tire sealant removal apparatus having a means of controlling the dimensions thereof (iii) into the tire and adjusting same to fit the dimensions of the layer of silicone self-sealing tire sealant; using the means of rotating either the tire relative to a stationary self-sealing tire sealant removal apparatus or self-sealing tire sealant removal apparatus relative to a stationary tire means (iv) to rotate the self-sealing tire sealant removal apparatus (iii) relative to a stationary tire to remove the layer of silicone self-sealing tire sealant from the inner surface of the tread; and collecting the removed silicone self-sealing tire sealant optionally with (v) the element for collecting removed silicone self-sealing tire sealant from a self-sealing tire. As previously indicated, it has been identified that despite its tackiness silicone sealants, in particular condensation cured silicone sealants, can be separated from the inner surface of a tire tread using the process described above because suitable condensation cured self-sealing tire silicone sealants applied on the inner surface of the tire tread in an SST imparts a good physical adhesion to the rubber but the condensation cured self-sealing tire silicone sealants used are not chemically bound to the inner surface of the tire tread because the condensation cured self-sealing tire silicone sealant does not induce any form of chemical bonding reaction with the rubber of inner surface (tread) of the tire tread. In one embodiment the puncture-resistant layer of silicone self-sealing tire sealant (typically a condensation cured self-sealing tire silicone sealant) is removed from the SST at a temperature of from room temperature (i.e., between 20oC and 25oC) to about 70oC. It was found that whilst it can be removed adequately well at room temperature in some instances an elevated temperature might be preferred. If desired the SST may be heated or cooled to a selected temperature to assist in the removal of the condensation cured self-sealing tire silicone sealant. In a further embodiment the condensation cured self-sealing tire silicone sealant may be treated with a solvent to assist in the removal thereof from the inner surface of the tread. Any suitable solvent may be selected from unreactive short-chain siloxanes or suitable organic solvents which are able to swell the sealant matrix. It has additionally been found that changes to the layer of silicone self-sealing tire sealant can help the process described herein. These include use of a self-sealing tire which comprises a tread having an inner and outer surface and sidewalls on opposite sides of said tread which sidewalls are spaced apart at a regular spacing and which has a layer of silicone self-sealing tire sealant on the inner surface of the tread; which layer of silicone self-sealing tire sealant has at least one of : a coating overlap in the layer of silicone self-sealing tire sealant, a liner applied to the layer of silicone self-sealing tire sealant; and a luminescence agent in or on the layer of silicone self-sealing tire sealant; to assist in the removal of the layer of silicone self-sealing tire sealant from the inner surface of the tire tread. The self-sealing tire comprises a standard shaped tire having a circular cross-section with a tread having an inner and outer surface and sidewalls on opposite sides of said tread. The sidewalls of the tire are opposite each other at a regular distance apart when in use during the life of the tire. The outer surface of the tread engages the road or surface on which the automobile is being driven or the like and the inner surface of the tread has a silicone sealant adhered thereto which is relied upon to seal any punctures encountered during normal use. In the present process a suitable self-sealing tire is optionally placed on or in support (i), if desired and then has a tire spreading means (ii) attached to each side wall. As previously discussed, the tire spreading means is typically an apparatus commonly referred to as a tire spreader. Usually such a tire spreader has tire engaging elements which engage the sidewalls on the opposite sides of the tire tread and transfer and fix said sidewalls in a spread position in which the tire sidewalls are spaced further apart than their regular spacing. Any suitable tire spreader may be utilised for this purpose, for example one where the user fixes the tire to a support and then opening the tire in the lateral / width direction or commercial tire spreaders such as a 5700 Tire Spreader from Branick Industries Inc. of North Dakota USA, which may be used when the process required a tire to rotate. Preferably, on average a minimum of 80 wt. %, alternatively a minimum of 90 wt. % alternatively a minimum of 95 wt. % of the layer of silicone self-sealing tire sealant is removed from the inner surface of the tire tread, preferably in a single operation i.e., after one complete rotation of the whole tire or one circuit of the inner surface of the tread when the tire is held rigid. The tire spreading means undertakes the above function thereby allowing for the insertion of the self-sealing tire sealant removal apparatus having a means of controlling the dimensions thereof (iii) into the tire. The inner layer of silicone self-sealing tire sealant is cut at any appropriate time in the procedure but is typically cut prior to insertion of the self-sealing tire sealant removal apparatus having a means of controlling the dimensions thereof (iii) into the tire. The dimensions of the self-sealing tire sealant removal apparatus having a means of controlling the dimensions thereof (iii) are adjusted using the means of controlling the dimensions thereof to fit the dimensions of the inner layer of silicone self-sealing tire sealant. This may involve changing the width of the means to be used to remove the inner layer of silicone self-sealing tire sealant so as to be able to remove the same in a single rotation and / or changing the position of the apparatus (iii) to ensure it is in the correct position to remove the inner layer of silicone self-sealing tire sealant dependent on the process to be undertaken. A roller, mandrel or screw is placed in the required position for collecting the peeled precut sealant and the width of thereof is adjusted, if required, to enable the sealant to be peeled off onto said roller, mandrel or screw (as selected) in a single peel operation. Once the roller, mandrel or screw is in the appropriate required position the precut sealant is attached thereto to peel off the layer of silicone self-sealing tire sealant and the roller, mandrel or screw is rotated relative to the tire so as to continuously peel off the sealant from the self-sealing tire. If desired, as discussed above a second roller or a plate may also be introduced for controlling the peeling angle at which the layer of silicone self-sealing tire sealant is removed. The second element can be positioned such that the peeling angle for the peeling process may from about 1° and about 90°, alternatively from about 5° to about 80°, alternatively from about 5° and about 70°, alternatively from about 10 ° to about 60°. The roller, mandrel or screw may be driven manually, electrically, pneumatically or by other power sources. Preferably the relative rotation speed of the roller, mandrel or screw, may be automatically adjusted and / or controlled to prevent breakage of the peeled off condensation cured self-sealing tire silicone sealant based on the tensile strength of the sealant. If desired a vibrating means may be incorporated on the roller, mandrel or screw to induce vibration or oscillation in the peel angle to help peeling the condensation cured self-sealing tire silicone sealant from the inner surface of the tire tread an example is an air-scraper. Furthermore, if desired the or each roller mandrel or screw may be designed to move from a sharp angle to a less sharp peeling angle as and when desired in order to improve efficiency of the system. Alternatively, the or each roller mandrel or screw may be designed to move back and forth in the direction of the collected product in order to induce extension forces that improve the efficiency of collecting the layer of silicone self-sealing tire sealant. It has been determined that the process relating to precutting step and engaging the precut sealant to the roller, mandrel or screw is improved by having a coating overlap in the layer of silicone self- sealing tire sealant to ease engagement of the cut sealant of the inner layer to the roller, mandrel or screw of the self-sealing tire sealant removal apparatus (iii) prior to the commencement of the process for sealant removal. Furthermore, as discussed above a liner may be applied to the layer of silicone self-sealing tire sealant prior to removal of the layer of silicone self-sealing tire sealant from the inner surface of the tire tread to aid peeling the sealant from the tire without breaking the sealant and / or if desired a luminescence agent may be provided in the layer of silicone self-sealing tire sealant or painted on the layer of silicone self-sealing tire sealant to make it easier to observe any part of the layer of silicone self-sealing tire sealant that remains on the inner surface of the tire tread. The peeling process alone is probably most suited when the condensation cured self-sealing tire silicone sealant is not as sticky / tacky to the touch and / or which has a larger tensile strength to allow smooth peeling without tensile breakage of the sealant during peeling and the condensation cured self-sealing tire silicone sealant being removed is merely peeled away from the inner surface of the tire tread onto the roller, mandrel or screw unless optional element (v) is used. Optionally however, an element such as a second roller or a plate for controlling the peeling angle may be utilised in the peeling configuration between the SST inner surface and the roller mandrel / screw is utilised to collect the removed sealant. Otherwise, the roller, mandrel or screw utilised functions as a peeling angle control element as well as sealant collecting element. The peeling angle is defined as the angle between the surface on the tire substrate from which the sealant is being removed and the plane of the sealant being transferred to the roller, mandrel or screw subsequent to peeling. Hence the peeling process may be as follows: a) Place a self-sealing tire containing a layer of silicone self-sealing tire sealant of condensation cured self-sealing tire silicone sealant on a support (i) or tire spreading means (ii) which allows a tire to be rotated or fixed in place while the roller, mandrel or screw is rotated; b) Precut the condensation cured layer of silicone self-sealing tire sealant across the whole tire width using a scraper or knife to provide a first cut end in the sealant and a second cut end in the sealant and connect the first cut end to a roller, mandrel or screw designed to collect the condensation cured layer of silicone self-sealing tire sealant subsequent to having been peeled from the inner surface of the tire tread; c) initiate peeling of the condensation cured self-sealing tire silicone sealant from the inner surface of the tire tread by rotating the roller, mandrel or screw relative to the tire enabling the peeled sealant to be collected on the roller, mandrel or screw with the roller, mandrel or screw positioned at a suitable peeling angle and distance from the sealant being peeled from the inner surface of the tire tread. d) rotate the roller, mandrel or screw at a desired peeling angle using a controlling roller to adjust the peeling angle in a desired range (typically an acute angle, i.e., an angle of less than 90o) thereby continuously peeling the condensation cured self-sealing tire silicone sealant from the inner surface of the tire tread and collecting the sealant as it is removed while simultaneously rotating the roller, mandrel or screw to continuously peel and collect the removed sealant. e) Once the sealant is removed from the SST to leave a substantially sealant-free tire tread, remove the tire tread from the support (i) or tire spreading means (ii) and collect the condensation cured self-sealing tire silicone sealant for further processing as described herein. In one embodiment a sensor such as a torque sensor or load cell may be utilised to detect the force tangential to the circumference of the roller, mandrel or screw and to control / adjust roller, mandrel or screw speeds to prevent breakage of the sealant being removed from the tire. If desired a vibration mechanism such as an air-scraper may be incorporated on the roller, mandrel or screw to induce some vibration and / or oscillation in the peel angle to help peeling the condensation cured self-sealing tire silicone sealant from the inner surface of the tire tread. Furthermore, if desired the or each roller, mandrel or screw may be designed to move from a sharp angle to a less sharp peeling angle as and when desired in order to improve efficiency of the system. Alternatively, the or each roller, mandrel or screw may be designed to move back and forth in the direction of the collected product in order to induce extension forces that improve efficiency of collected product. Typically, once the layer of silicone self-sealing tire sealant has been removed from the self-sealing tire the remaining tire body is recycled in a standard manner. For example, usually reinforcing materials, particularly reinforcing wires, reinforcing fibres or both made from one or more of metals, polymers, and / or glass are removed from the body. This is most often the removal of steel wires if required. This step is deemed optional dependent on whether or not they need to be removed in view of the subsequent processes being undertaken. Steel wires may be extracted using suitable metal wire separators or the like which are industrially available and well known in the art. Once the reinforcing materials are removed, if required the remaining rubber from the tire body can be recycled via any suitable process such as but not limited to shredding, grinding, milling, pulverizing, cryogenic processing and / or pyrolysis. Any of these processes can be used to reduce the size of the pieces of residual rubber and these can then be further processed or regulated using granulators and screens and the like. The other main way of reducing the size of the residual rubber is via a cryogenic process whereby the tire bodies, with the layer of silicone self-sealing tire sealant removed are frozen, usually utilising liquid nitrogen and then crushed whilst frozen using a suitable apparatus such as a hammer crusher or hammer mill. Typically, when using this cryogenic process, it is less important to first remove the reinforcing materials, especially steel wires as the steel wires can be extracted using magnets after crushing if preferred. Other materials and detritus may be extracted by either screening processes or via an air classifier or the like which is able to separate materials by a combination or size, shape and / or density. Resulting rubber pieces / particles may subsequently be cleaned and utilised as a product or further processed. If desired, the shredded or cryogenically smashed rubber pieces may be further treated using one or more chemical processes. In a further alternative, whole or shredded or cryogenically smashed tires may be pyrolised to provide fuel oil, char products such as carbon black and or solid fuels and gaseous products such as hydrogen, short chain hydrocarbons having from 1 to 6 carbons (usually 1 to 4 carbons), carbon dioxide and carbon monoxide. Typically, in tire pyrolysis the tire bodies or broken-down rubber pieces undergo thermal degradation at temperatures in the range of 500oC. Likewise, the accumulated layers of silicone self-sealing tire sealant may be recycled for example by the chemical recycling using depolymerization to produce low molecular weight oligomers which can be utilised in the preparation of siloxane polymers or may alternatively also undergo both pyrolysis and / or mechanical recycling. A further route for recycling shredded tire materials of construction without removing the steel band or wires is via the use of these materials in the Portland cement manufacturing. There are two main method types for recycling / reclaiming silicone elastomeric materials such as the layers of silicone self-sealing tire sealant. Given silicone elastomers are thermoset materials once cured these tend to be via “chemical processes” such as pyrolysis, chemical degradation and chemical reversion and by “physical processes”, i.e., mechanical processes such as mechanical reclaiming, thermo-mechanical reclaiming and cryo-mechanical reclaiming and wet / solution grinding methods. Given silicone elastomers are thermoset materials chemical recycling of silicone elastomers is not ideal for reclaiming / recycling requires significant separation from other materials when present. When layers of silicone self-sealing tire sealant are to be recycled using physical recycling methods they can be transformed into powders, granules, crumbs, or pellets (referred to collectively herein as “particulates”). For the avoidance of doubt for the sake of this disclosure physically ( mechanically) recycled / reclaimed particulates have their original crosslinked structure preserved, whereas chemically recycled materials do not. When the preformed silicone elastomeric particulates are physically recycled or reclaimed silicone elastomeric particulates, any suitable physical recycling method including mechanical reclaiming, thermo-mechanical reclaiming, cryomechanical reclaiming, and wet / solution grinding can be utilised to obtain the particulates. Examples of methods which may be utilised to generate the particulates include, for the sake of example, cryomilling (at liquid nitrogen temperatures), using milling equipment known in the art such as ball mills, pin mills, and the like, tornado milling (which can be done at either ambient or cryogenic temperatures in the solid state) and wet jet milling (used to disintegrate agglomerates of powder / polymer samples in a liquid phase, i.e. in this case where the rubber is pulverized by an intense water stream. Given the silicone self-sealing tire sealant utilised herein is typically a condensation cured silicone sealant, they are physically and not chemically bound to the tire. Hence, they can be far more effectively and efficiently removed from the tire tread using the apparatus and method described herein than butyl rubber type sealants which are chemically bound to the tire tread (tread). This provides the recycler to separately recycle the tire tread (in a manner analogous to standard tires) and the condensation cured silicone sealants. For example, once the puncture-resistant layer of silicone self-sealing tire sealant (typically a condensation cured silicone sealant) has been removed the tire tread can be recycled in the same way as conventional (non-SST) tires e.g., by using, for example, mechanical shredding operations or other tire recycling techniques, thus rendering issues such as tires pre-sorting and shredder “gumming up” can be avoided, enabling to be recycled as simply as standard non-SST tires. The condensation cured self-sealing tire silicone sealant utilised for SSTs may include the cured products of suitable condensation curable self-sealing tire silicone sealant compositions described in US Patent 10844177, and US Patent Application Publication 2023-0391960 (both of which are incorporated herein by reference) and the self-seal tire sealant SILASTIC™ SST-2650 sealant commercially available from Dow Silicones Corporation. These may include: a two-part condensation curable self-sealing tire silicone sealant composition comprising: a. at least one condensation curable silyl terminated polymer having at least one, typically at least two hydroxyl functional groups per molecule; b. a cross-linker selected from the group of • silanes having at least 2 hydrolysable groups, alternatively at least 3 hydrolysable groups per molecule group; and / or • silyl functional molecules having at least 2 silyl groups, each silyl group containing at least one hydrolysable group, and c. a condensation catalyst selected from the group of titanates and / or zirconates; wherein (i), (ii) and (iii) are not stored together in a single part, characterized in that the molar ratio of total silicon bonded hydroxyl (Si-OH) groups to total hydrolysable groups is between 0.5 : 1 and 3:1 using a silyl containing cross linker or 0.5:1 to 10 : 1, alternatively 0.5:1 to 4 : 1 using silyl functional molecules containing crosslinker and the molar ratio of catalyst M-OR functions to the sum of moisture present in the composition, as determined in accordance with ISO 787-2:1981, and total silicon bonded hydroxyl groups is between 0.01:1 and 0.6:1, where M is titanium or zirconium and R is a monovalent, primary, secondary or tertiary aliphatic hydrocarbon group which may be linear or branched containing from 1 to 10 carbon atoms, typically a linear or branched alkyl group. It is to be understood that for the sake of this application that “total hydrolysable groups” excludes both moisture and silicon bonded hydroxyl groups present in the composition. The total silicon bonded hydroxyl (Si-OH) molar content is calculated for 100 g of the mixed formulation. The total silicon bonded hydroxyl molar content related to a polymer is equal to the amount in g of hydroxyl containing polymer in 100g of the mixed product divided by the number average molecular weight (Mn) of the polymer multiply by the average number of hydroxyl functions present in the polymer, typically 2. If there are several hydroxyl functional polymers in the formulation, the sum of the molar content of each polymer is sum up to constitute the total silicon bonded hydroxyl (Si-OH) molar content in the formulation. The number average molecular weight (Mn) and weight average molecular weight (Mw) of silicone can also be determined by Gel permeation chromatography (GPC). This technique is a standard technique, and yields values for Mw (weight average), Mn (number average) and polydispersity index (PI) (where PI=Mw / Mn). Mn values provided in this application have been determined by GPC and represent a typical value of the polymer used. If not provided by GPC, the Mn may also be obtained from calculation based on the dynamic viscosity of said polymer. The catalyst M-OR value is = [(g of Titanate catalyst)*(number of OR in compound)] divided by the (molecular weight of Titanium catalyst). The condensation curable self-sealing tire silicone sealant composition typically used as the silicone self-sealing tire sealant has a viscosity, when uncured, that permits the condensation curable self- sealing tire silicone sealant composition to be incorporated into a tire during a tire building process and a viscosity that, when cured, permits the condensation cured self-sealing tire silicone sealant to flow into and seal a puncture in a tire. Polymer (i) is at least one moisture / condensation curable silyl terminated polymer. Any suitable moisture / condensation curable silyl terminated polymer may be utilised including polydialkyl siloxanes, alkylphenyl siloxane, or organic based polymers with silyl terminal groups e.g., silyl polyethers, silyl acrylates and silyl terminated polyisobutylenes or copolymers of any of the above. Preferably the polymer is a polysiloxane based polymer containing at least one hydroxyl, most preferably the polymer comprises two terminal hydroxyl groups. Examples of suitable hydroxyl containing groups include –Si(OH)3,-(Ra)Si(OH)2, -(Ra)2Si(OH), or –(Ra)2Si -Rc- SiRdp(OH)3-pwhere each Raindependently represents a monovalent hydrocarbyl group, for example, an alkyl group, in particular having from 1 to 8 carbon atoms, (and is preferably methyl); each Rdgroup is independently an alkyl group in which the alkyl groups suitably have up to 6 carbon atoms; Rcis a divalent hydrocarbon group having up to 12 carbon atoms which may be interrupted by one or more siloxane spacers having up to six silicon atoms; and p has the value 0, 1 or 2. Preferably polymer (i) has the general formula. X3-A-X1(1) where X3and X1are independently selected from siloxane groups which terminate in hydroxyl containing groups and A is a siloxane and / or organic containing polymeric chain, alternatively a siloxane polymeric chain. Examples of hydroxyl-terminating groups X3or X1include: –Si(OH)3, -(Ra)Si(OH)2, -(Ra)2Si(OH), or–(Ra)2 Si -Rc- Si (Rd)p(OH)3-p as defined above. Preferably the X3and / or X1terminal groups are hydroxydialkyl silyl groups, e.g., hydroxydimethyl silyl groups. Examples of suitable siloxane groups in polymeric chain A of formula (I) are those which comprise a polydiorgano-siloxane chain. Thus, polymeric chain A preferably includes siloxane units of formula (2) -(R5sSiO(4-s) / 2)- (2) in which each R5is independently an organic group such as a hydrocarbyl group having from 1 to 10 carbon atoms optionally substituted with one or more halogen group such as chlorine or fluorine and s is 0, 1 or 2, typically s is about 2. Particular examples of groups R5include methyl, ethyl, propyl, butyl, vinyl, cyclohexyl, phenyl, tolyl group, a propyl group substituted with chlorine or fluorine such as 3,3,3-trifluoropropyl, chlorophenyl, beta-(perfluorobutyl)ethyl or chlorocyclohexyl group. Suitably, at least some and preferably substantially all of the groups R5are methyl. Typically, the polymers of the above type will have a viscosity in the order of 1,000 to 300,000 mPa.s, alternatively 1,000 to 100,000 mPa.s at 23oC measured by using a Brookfield cone plate viscometer (RV DIII) using the most appropriate cone plate for the viscosity concerned. Preferred polysiloxanes containing units of formula (2) are thus polydiorganosiloxanes having terminal, silicon-bound hydroxyl groups or terminal, silicon-bound organic radicals which can be hydrolysed using moisture as defined above. The polydiorganosiloxanes may be homopolymers or copolymers. Mixtures of different polydiorganosiloxanes having terminal condensable groups are also suitable. For the purpose of this application “substituted” means one or more hydrogen atoms in a hydrocarbon group has been replaced with another substituent. Examples of such substituents include, but are not limited to, halogen atoms such as chlorine, fluorine, bromine, and iodine; halogen atom containing groups such as chloromethyl, perfluorobutyl, trifluoroethyl, and nonafluorohexyl; oxygen atoms; oxygen atom containing groups such as (meth)acrylic and carboxyl; nitrogen atoms; nitrogen atom containing groups such as amino-functional groups, amido- functional groups, and cyano-functional groups; sulphur atoms; and sulphur atom containing groups such as mercapto groups. Crosslinkers (ii) that can be used are generally moisture curing. - silanes having at least 2 hydrolysable groups, alternatively at least 3 hydrolysable groups per molecule group; and / or - silyl functional molecules having at least 2 silyl groups, each silyl group containing at least one hydrolysable group. In some instances, the crosslinker (ii) having two hydrolysable groups may be considered a chain extender, i.e., when polymer (i) only has 1 or two reactive groups but can be used to cross-link if polymer (i) has 3 or more reactive groups per molecule. The crosslinker (ii) may thus have two but alternatively has three or four silicon-bonded condensable (preferably hydroxyl and / or hydrolysable) groups per molecule which are reactive with the condensable groups in polymer (i). For the sake of the disclosure herein silyl functional molecule is a silyl functional molecule containing two or more silyl groups, each silyl group containing at least one hydrolysable group. Hence, a disilyl functional molecule comprises two silicon atoms each having at least one hydrolysable group, where the silicon atoms are separated by an organic or siloxane spacer. Typically, the silyl groups on a disilyl functional molecule may be terminal groups. The spacer may be a polymeric chain. For the sake of the disclosure herein a disilane is a silyl functional molecule having at least 2 silyl groups where the two silicon atoms are bonded to one another. The hydrolysable groups on the silyl groups include acyloxy groups (for example, acetoxy, octanoyloxy, and benzoyloxy groups); ketoximino groups (for example dimethyl ketoximo, and isobutylketoximino); alkoxy groups (for example methoxy, ethoxy, and propoxy) and alkenyloxy groups (for example isopropenyloxy and 1-ethyl-2-methylvinyloxy). In some instances, the hydrolysable group may include hydroxyl groups. The silane cross-linker (ii) includes alkoxy functional silanes, oximosilanes, acetoxy silanes, acetonoxime silanes and / or enoxy silanes. When the crosslinker is a silane and when the silane has three silicon-bonded hydrolysable groups per molecule, the fourth group is suitably a non-hydrolysable silicon-bonded organic group. These silicon-bonded organic groups are suitably hydrocarbyl groups which are optionally substituted by halogen such as fluorine and chlorine. Examples of such fourth groups include alkyl groups (for example methyl, ethyl, propyl, and butyl); cycloalkyl groups (for example cyclopentyl and cyclohexyl); alkenyl groups (for example vinyl and allyl); aryl groups (for example phenyl, and tolyl); aralkyl groups (for example 2-phenylethyl) and groups obtained by replacing all or part of the hydrogen in the preceding organic groups with halogen. The fourth silicon-bonded organic groups may be methyl. A typical silane may be described by formula (3) R"4-rSi(OR5)r(3) wherein R5is described above and r has a value of 2, 3 or 4. Typical silanes are those wherein R" represents methyl, ethyl, vinyl, or isobutyl. R" is an organic radical selected from linear and branched alkyls, allyls, phenyl and substituted phenyls, acethoxy, oxime. In some instances, R5represents methyl or ethyl and r is 3. Another type of suitable crosslinkers (ii) are molecules of the type of Si(OR5)4 where R5is as described above, alternatively propyl, ethyl or methyl. Partial condensates of Si(OR5)4 may also be considered. In one embodiment the cross-linker (ii) is a silyl functional molecule having at least 2 silyl groups each having at least 1 and up to 3 hydrolysable groups, alternatively each silyl group has at least 2 hydrolysable groups. The crosslinker (ii) may be a disilyl functional polymer, that is, a polymer containing two silyl groups, each containing at least one hydrolysable group such as described by the formula (4) (R4O)m(Y1)3-m – Si (CH2)x – ((NHCH2CH2)t - Q(CH2)x)n - Si(OR4)m(Y1)3-m (4) where R4is a C1-10 alkyl group, Y1is an alkyl groups containing from 1 to 8 carbons, Q is a chemical group containing a heteroatom with a lone pair of electrons e.g., an amine, N- alkylamine or urea; each x is an integer of from 1 to 6, t is 0 or 1; each m is independently 1, 2 or 3 and n is 0 or 1. The silyl (e.g., disilyl) functional crosslinker (ii) may have a siloxane or organic polymeric backbone. Suitable polymeric crosslinkers (ii) may have a similar polymeric backbone chemical structure to polymeric chain A as depicted in formula (1) above. In the case of such siloxane or organic based cross-linkers the molecular structure can be straight chained, branched, cyclic or macromolecular, i.e., a silicone or organic polymer chain bearing alkoxy functional end groups include polydimethylsiloxanes having at least one trialkoxy terminal where the alkoxy group may be a methoxy or ethoxy group. In the case of siloxane-based polymers the viscosity of the cross-linker will be within the range of from 0.5 mPa.s to 80,000 mPa.s at 23oC using a Brookfield cone plate viscometer (RV DIII) utilising a cone plate (measured in the same manner as polymer (i)). Whilst any of the hydrolysable groups mentioned above are suitable it is preferred that the hydrolysable groups are alkoxy groups and as such the terminal silyl groups may have the formula such as -RaSi(ORb)2, -Si(ORb)3, - Ra2SiORbor –(Ra)2Si -Rc- SiRdp(ORb)3-pwhere each Raindependently represents a monovalent hydrocarbyl group, for example, an alkyl group, in particular having from 1 to 8 carbon atoms, (and is preferably methyl); each Rband Rdgroup is independently an alkyl group having up to 6 carbon atoms; Rcis a divalent hydrocarbon group which may be interrupted by one or more siloxane spacers having up to six silicon atoms; and p has the value 0, 1 or 2. Typically each terminal silyl group will have 2 or 3 alkoxy groups. Examples of disilyl polymeric crosslinkers (ii) with a silicone or organic polymer chain bearing alkoxy functional end groups include 1,6-bis (trimethoxysilyl)hexane (alternatively known as hexamethoxydisilylhexane HMSH), polydimethylsiloxanes having at least one trialkoxy terminal where the alkoxy group may be a methoxy or ethoxy group. Crosslinkers (ii) thus include alkyltrialkoxysilanes such as methyltrimethoxysilane (MTM) and methyltriethoxysilane, tetraethoxysilane, partially condensed tetraethoxysilane, alkenyltrialkoxy silanes such as vinyltrimethoxysilane and vinyltriethoxysilane, isobutyltrimethoxysilane (iBTM). Other suitable silanes include ethyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, alkoxytrioximosilane, alkenyltrioximosilane, 3,3,3-trifluoropropyltrimethoxysilane, methyltriacetoxysilane, vinyltriacetoxysilane, ethyl triacetoxysilane, di-butoxy diacetoxysilane, phenyl-tripropionoxysilane, methyltris(methylethylketoximo)silane, vinyl-tris- methylethylketoximo)silane, methyltris(methylethylketoximino)silane, methyltris(isopropenoxy)silane, vinyltris(isopropenoxy)silane, ethylpolysilicate, n- propylorthosilicate, ethylorthosilicate, dimethyltetraacetoxydisiloxane, oximosilanes, acetoxy silanes, acetonoxime silanes, enoxy silanes and other such trifunctional alkoxysilanes as well as partial hydrolytic condensation products thereof; bis (trialkoxysilylalkyl)amines, bis (dialkoxyalkylsilylalkyl)amine, bis (trialkoxysilylalkyl) N-alkylamine, bis (dialkoxyalkylsilylalkyl) N-alkylamine, bis (trialkoxysilylalkyl)urea, bis (dialkoxyalkylsilylalkyl) urea, bis (3- trimethoxysilylpropyl)amine, bis (3-triethoxysilylpropyl)amine, bis (4-trimethoxysilylbutyl)amine, bis (4-triethoxysilylbutyl)amine, bis (3-trimethoxysilylpropyl)N-methylamine, bis (3-triethoxysilylpropyl) N-methylamine, bis (4-trimethoxysilylbutyl) N-methylamine, bis (4- triethoxysilylbutyl) N-methylamine, bis (3-trimethoxysilylpropyl)urea, bis (3-triethoxysilylpropyl)urea, bis (4-trimethoxysilylbutyl)urea, bis (4-triethoxysilylbutyl)urea, bis (3-dimethoxymethylsilylpropyl)amine, bis (3-diethoxymethyl silylpropyl)amine, bis (4- dimethoxymethylsilylbutyl)amine, bis (4- diethoxymethyl silylbutyl)amine, bis (3-dimethoxymethylsilylpropyl) N-methylamine, bis (3-diethoxymethyl silylpropyl) N-methylamine, bis (4-dimethoxymethylsilylbutyl) N-methylamine, bis (4- diethoxymethyl silylbutyl) N-methylamine, bis (3-dimethoxymethylsilylpropyl)urea, bis (3- diethoxymethyl silylpropyl)urea, bis (4-dimethoxymethylsilylbutyl)urea, bis (4- diethoxymethyl silylbutyl)urea, bis (3-dimethoxyethylsilylpropyl)amine, bis (3-diethoxyethyl silylpropyl)amine, bis (4-dimethoxyethylsilylbutyl)amine, bis (4- diethoxyethyl silylbutyl)amine, bis (3-dimethoxyethylsilylpropyl) N-methylamine, bis (3- diethoxyethyl silylpropyl) N-methylamine, bis (4-dimethoxyethylsilylbutyl) N-methylamine, bis (4- diethoxyethyl silylbutyl) N-methylamine, bis (3-dimethoxyethylsilylpropyl)urea bis (3- diethoxyethyl silylpropyl)urea, bis (4-dimethoxyethylsilylbutyl)urea and / or bis (4- diethoxyethyl silylbutyl)urea; bis (triethoxysilylpropyl)amine, bis (trimethoxysilylpropyl)amine, bis (trimethoxysilylpropyl)urea, bis (triethoxysilylpropyl)urea, bis (diethoxymethylsilylpropyl)N-methylamine; di or trialkoxy silyl terminated polydialkyl siloxane, di or trialkoxy silyl terminated polyarylalkyl siloxanes, di or trialkoxy silyl terminated polypropylene oxide, polyurethane, polyacrylates; polyisobutylenes; di or triacetoxy silyl terminated polydialkyl; polyarylalkyl siloxane; di or trioximino silyl terminated polydialkyl; polyarylalkyl siloxane; di or triacetonoxy terminated polydialkyl or polyarylalkyl. The cross-linker (ii) used may also comprise any combination of two or more of the above. The molar ratio of total silicon bonded hydroxyl groups to total hydrolysable groups is between 0.4: 1 and 2:1 using a mono silyl containing cross linker or 0.5:1 to 4: 1 using disilyl containing crosslinker. In one alternative the molar ratio of total silicon bonded hydroxyl groups to total hydrolysable groups is between 1:1 and 2:1. The total hydrolysable groups molar content is calculated for 100g of the mixed formulation. The molar content of hydrolysable groups related to a substance is equal to the amount in g of the molecule that contains the hydrolysable groups in 100g of the mixed product divided by the molecular weight of the molecule or the number average molecular weight (Mn) in case it is a polymeric molecule multiply by the average number of hydrolysable functions present in the molecule. The sum of the molar content of each molecule or polymer is sum up to constitute the total molar content of hydrolysable groups in the formulation. The molar ratio of total silicon bonded hydroxyl groups to total hydrolysable groups is then calculated by dividing the total molar content of total silicon bonded hydroxyl (Si-OH) groups by the total molar content of hydrolysable groups or can be depicted as a ratio. The condensation curable self-sealing tire silicone sealant composition further comprises a condensation catalyst. This increases the speed at which the composition cures. The catalyst chosen for inclusion in a particular condensation curable self-sealing tire silicone sealant composition depends upon the speed of cure required. Titanate and / or zirconate-based catalysts may comprise a titanate ester compound according to the general formula Ti[OR22]4 or Zr[OR22]4 where each R22may be the same or different and represents a monovalent, primary, secondary or tertiary aliphatic hydrocarbon group which may be linear or branched containing from 1 to 10 carbon atoms. Optionally the titanate and / or zirconate-based catalysts may contain partially unsaturated groups. Examples of R22include but are not restricted to methyl, ethyl, propyl, isopropyl, butyl, tertiary butyl and a branched secondary alkyl group such as 2, 4-dimethyl-3-pentyl. Alternatively, when each R22is the same, R22is an isopropyl, branched secondary alkyl group or a tertiary alkyl group, in particular, tertiary butyl. Suitable titanate-based catalyst examples include tetra n-butyl titanate, tetra t-butyl titanate, titanium tetrabutoxide and tetraisopropyl titanate. Suitable zirconate-based catalyst examples include tetra-n-propyl zirconate, tetra-n-butyl zirconate and zirconium diethylcitrate. Alternatively, the titanate and / or zirconate-based catalysts may be chelated. The chelation may be with any suitable chelating agent such as an alkyl acetylacetonate such as methyl or ethylacetylacetonate. Alternatively, the titanate may be monoalkoxy titanates bearing three chelating agents such as for example 2-propanolato, tris isooctadecanoato titanate or diisopropyldiethylacetoacetate titanate. The molar ratio of catalyst M-OR functions to the sum of moisture present in the composition, as determined in accordance with ISO 787-2:1981 and total silicon bonded hydroxyl groups is between 0.01:1 and 0.6:1, where M is titanium or zirconium. The condensation curable self-sealing tire silicone sealant composition as hereinbefore described is typically made from the condensation curable gel or elastomer composition which is stored in a 2- part manner. The two-part compositions may be mixed using any appropriate standard two-part mixing apparatus with a dynamic or static mixer and is optionally dispensed therefrom for use in the application for which it is intended. In one embodiment, the two-part condensation curable self-sealing tire silicone sealant composition is stored in two parts where said parts may be divided as follows: a) polymer(i) and cross-linker (ii) in one part and polymer (i) and catalyst (iii) in the other part; b) cross-linker (ii) in one part and polymer (i) and catalyst (iii) in the other part or c) when more than one polymer (i) is being utilised a first polymer(i) and cross-linker (ii) in one part and a second polymer (i) and catalyst (iii) in the other part; d) polymer (i) in one part and the cross-linker (ii) and catalyst (iii) in the other part. In each case the filler and catalyst are not in the same part. Typically, when present, filler is mixed with polymer (i) in a base part which may also contain other additives. The two parts can be mixed in any suitable ratio, e.g., base part : catalyst package for example from 15 : 1 to 1 :1, alternatively 10 : 1 to 1:1, alternatively 5 : 1 to 1 : 1, preferably 1 :1. Optional Ingredients Other than the above components optional components may be blended in the condensation curable self-sealing tire silicone sealant composition within suitable ranges. Examples of optional components include fillers, heat resistance-imparting agents, cold resistance- imparting agents, flame retarders, thixotropy-imparting agents, pigments, surfactants, flux agents, acid acceptors, protection agents, UV stabilizers, antioxidants, antiozonants, anti-corrosion additives, dyes and any suitable combination thereof. Fillers The two-part condensation curable self-sealing tire silicone sealant composition may incorporate fillers, for example reinforcing and / or non reinforcing inorganic fillers, thermally and / or electrically conductive fillers e.g., metallic fillers and meltable fillers, or a combination thereof. Examples of finely divided, reinforcing fillers include high surface area fumed and precipitated silicas including rice hull ash and to a degree calcium carbonate. Examples of additional finely divided non-reinforcing fillers include crushed quartz, diatomaceous earths, barium sulphate, iron oxide, titanium dioxide, carbon black, glass beads, hollow glass beads, talc, wollastonite. Other fillers which might be used alone or in addition to the above include carbon nanotubes, e.g., multiwall carbon nanotubes, carbon fibres, aluminite, calcium sulphate (anhydrite), gypsum, calcium sulphate, barium titanate, magnesium carbonate, clays such as kaolin, aluminium trihydroxide, magnesium hydroxide (brucite), graphite, diamond, copper carbonate, e.g., malachite, nickel carbonate, e.g., zarachite, barium carbonate, e.g., witherite and / or strontium carbonate e.g., strontianite. Examples of anhydrous inorganic fillers include onyx; aluminium trihydrate, metal oxides such as aluminium oxide, beryllium oxide, magnesium oxide, zinc oxide; nitrides such as aluminium nitride and boron nitride; carbides such as silicon carbide and tungsten carbide; and combinations thereof. Further examples of fillers include aluminium oxide, silicates from the group consisting of olivine group; garnet group; aluminosilicates; ring silicates; chain silicates; and sheet silicates. The olivine group comprises silicate minerals, such as but not limited to, forsterite and Mg2SiO4. The garnet group comprises ground silicate minerals, such as but not limited to, pyrope; Mg3Al2Si3O12; grossular; and Ca2Al2Si3O12. Aluminosilicates comprise ground silicate minerals, such as but not limited to, sillimanite; Al2SiO5; mullite; 3Al2O3.2SiO2; kyanite; and Al2SiO5. The ring silicates group comprises silicate minerals, such as but not limited to, cordierite and Al3(Mg,Fe)2[Si4AlO18]. The chain silicates group comprises ground silicate minerals, such as but not limited to, wollastonite and Ca[SiO3]. The sheet silicates group comprises silicate minerals, such as but not limited to, mica; K2AI14[Si6Al2O20](OH)4; pyrophyllite; Al4[Si8O20](OH)4; talc; Mg6[Si8O20](OH)4; serpentine for example, asbestos; Kaolinite; Al4[Si4O10](OH)8; and vermiculite. Any combination of two or more of the above fillers may be used. When present in a preferred embodiment the fillers utilised are selected from fumed and precipitated silicas, calcium carbonate, carbon black, hollow glass beads and / or carbon nanotubes, e.g., multiwall carbon nanotubes, and mixtures thereof. Filler Treating Agent The conductive fillers and / or the anhydrous reinforcing and / or extending filler if present, may optionally be surface treated with a treating agent. Treating agents and treating methods are known in the art. The surface treatment of the filler(s) is typically performed, for example with a fatty acid or a fatty acid ester such as a stearate, or with organosilanes, organosiloxanes, or organosilazanes such as hexaalkyl disilazane or short chain siloxane diols. Generally, the surface treatment renders the filler(s) hydrophobic and therefore easier to handle and obtain a homogeneous mixture with the other components in the composition. Silanes such as R5eSi(OR6)4-e wherein R5is a substituted or unsubstituted monovalent hydrocarbon group of 6 to 20 carbon atoms, for example, alkyl groups such as hexyl, octyl, dodecyl, tetradecyl, hexadecyl, and octadecyl, and aralkyl groups such as benzyl and phenylethyl, with the alkyl groups of 6 to 20 carbon atoms being preferred., R6is an alkyl group of 1 to 6 carbon atoms, and letter e is equal to 1, 2 or 3 may also be utilised as the treating agent for fillers. Adhesion Promoter Suitable adhesion promoters may comprise alkoxysilanes of the formula R14hSi(OR15)(4-h), where subscript h is 1, 2, or 3, alternatively h is 3. Each R14is independently a monovalent organofunctional group. R14can be an epoxy functional group such as glycidoxypropyl or (epoxycyclohexyl)ethyl, an amino functional group such as aminoethylaminopropyl or aminopropyl, a methacryloxypropyl, a mercapto functional group such as mercaptopropyl or an unsaturated organic group. Each R15is independently an unsubstituted, saturated hydrocarbon group of at least 1 carbon atom. R15may have 1 to 4 carbon atoms, alternatively 1 to 2 carbon atoms. R15is exemplified by methyl, ethyl, n-propyl, and iso- propyl. Examples of suitable adhesion promoters include glycidoxypropyltrimethoxysilane and a combination of glycidoxypropyltrimethoxysilane with an aluminium chelate or zirconium chelate. Examples of adhesion promoters may be found in U.S. Patent 4,087,585 and U.S. Patent 5,194,649. The condensation curable self-sealing tire silicone sealant composition may comprise, when present, 0.01% to 2wt.%, alternatively 0.05 to 2 wt.%, alternatively 0.1 to 1 wt. % of adhesion promoter based on the weight of the composition. Preferably, the speed of hydrolysis of the adhesion promoter should be lower than the speed of hydrolysis of the cross-linker in order to favour diffusion of the molecule towards the substrate rather than its incorporation in the product network. The two-part composition is mixed in a suitable mixing / dosing unit and the mixed composition is immediately applied onto the target substrate (tire) surface. Post mixing the composition is designed to have sufficient green strength to adhere to the tire inner surface and will cure after several hours. Typically, the two-part condensation curable self-sealing tire silicone sealant composition is applied in an uncured state and cures upon mixing and deposition on the substrate tire surface so as to have a cured thickness of between 0.25 and 10 mm, alternatively between 0.5 mm and 10 mm, alternatively between 1 and 5 mm, depending on the end use as discussed below. Subsequent to intermixing but prior to cure the condensation curable self-sealing tire silicone sealant composition may be applied on to a substrate using a suitable dispenser such as for example curtain coaters, spray devices die coaters, dip coaters, extrusion coaters, knife coaters and screen coaters which upon cure formation is provides a coating on said substrate. The thickness and pressure requirements required will vary depending on the end use of the tire concerned. Thus, for example, for tires of passenger vehicle type, it can have a thickness of at least 0.5 mm, preferably between 1 and 5 mm. According to another example, for tires for heavy duty or agricultural vehicles, the preferred thickness can lie between 1 and 6 mm. According to another example, for tires for vehicles in the field of earthmoving apparatus or for aircraft, the preferred thickness can lie between 2 and 10 mm. Finally, according to another example, for bicycle tires, the preferred thickness can lie between 0.4 and 2 mm. The condensation cured self-sealing tire silicone sealant derived from the two-part condensation curable self-sealing tire silicone sealant composition described above is a tacky solid (at 23° C) and is characterized in particular, thanks to its specific formulation, by a very high flexibility and deformability. One advantage of use of the composition as described herein is that the cured layer has the advantage of exhibiting, within a very wide range of operating temperatures for the tires, virtually no disadvantage in terms of rolling resistance in comparison with a tire not comprising a self-sealing layer. In comparison with non-silicone self-sealing compositions, the risks of excessive creep during use at relatively high temperature (typically greater than 60° C), a temperature frequently encountered during the use of some tires, are notably reduced as silicone-based materials are more resistant to extreme temperature changes than many organic alternatives. Its self-sealing properties are also improved during use at low temperature (typically less than 0° C). Furthermore, the condensation cured self-sealing tire silicone sealant derived from the aforementioned condensation curable self-sealing tire silicone sealant composition has a storage modulus of between 9,000 and 26,000 Pa. A storage modulus comprised between these two values has been identified to provide the right balance between softness (tackiness to the nail or itself) and hardness (creep / flow resistance under pressure). A silicone formulation exhibiting such a storage modulus at 23ºC will exhibit a storage modulus at other temperatures, i.e., from - 25 to 100ºC, which still is compliant with the required balance of modulus to act as a self-sealing coating for tires. If a foreign body, such as a nail, passes through the structure of the tire, the sealant serving as a self- sealing layer is subjected to several stresses. In reaction to these stresses, and thanks to its advantageous deformability and elasticity properties, said sealant creates an impermeable contact zone around the body. It does not matter whether the contour or the profile of said body is uniform or regular, the flexibility of the self-sealing sealant enables it to be insinuated into openings of very small size. This interaction between the self-sealing composition and the foreign body seals the zone affected by said body. In the event of the foreign body being removed, whether accidentally or intentionally, a perforation remains, this being liable to create a relatively large leak, depending on its size. The condensation curable self-sealing tire silicone sealant composition, exposed to the hydrostatic pressure, is sufficiently soft and deformable to seal off, by being deformed, the perforation, preventing the inflation gas from leaking. In particular in the case of a tire, it has been shown that the flexibility of the self-sealing sealant enables the forces of the surrounding walls to be withstood without any problems, even during phases in which the loaded tire deforms when running / rolling. used again on vehicles. Once recycled the SST rubber tire tread may be utilised as a means of shock absorption, sound absorption, non-slip, insulting and abrasion and crack resistant applications. For example, it may be used in construction materials, e.g., for resurfacing playgrounds and artificial sports fields, can be used in in road surfacing materials e.g., as ground and crumb rubber for rubberized asphalt, or in aggregate and or concrete but can also be incorporated in anti-slip mats and other carpet mats, shock cushioning in shock absorbing applications. Gases, liquids and solid ashes can result from pyrolysis. The gases may be used e.g., as fuels, the liquid may also be utilised for fuel and the solid material, being carbon based can be used as a source for e.g., carbon black and carbon electrodes. As previously indicated the recycled condensation cured self-sealing tire silicone sealant may be utilised as siloxane oligomers which can be reused to make siloxane polymers.

Claims

CLAIMS 1. A self-sealing tire recycling apparatus comprising the following components: (i) an optional support, (ii) a tire spreading means; (iii) a self-sealing tire sealant removal apparatus in the form of a roller, mandrel or screw adapted to receive precut sealant attached to it before continuously peeling off a layer of a silicone self-sealing tire sealant from a self-sealing tire optionally in combination with a suitable nozzle designed to remove the layer of silicone self-sealing tire sealant from a self-sealing tire by way of directing pressurized fluids at the layer of silicone self-sealing tire sealant having a means of controlling the dimensions thereof so as to be adaptable to fit the dimensions of the layer of silicone self-sealing tire sealant in a self-sealing tire to enable removal in a single operation; (iv) a means of rotating the self-sealing tire sealant removal apparatus relative to a stationary tire; and optionally (v) an element for collecting removed silicone self-sealing tire sealant from a self-sealing tire comprising at least one of (a’) a container with one side open or a moving conveyor belt to receive the removed sealant; and (b’) a vacuum sucking device.

2. A self-sealing tire recycling apparatus in accordance with claim 1 wherein the self-sealing tire sealant removal apparatus having a means of controlling the dimensions thereof so as to be adaptable to fit the dimensions of a layer of silicone self-sealing tire sealant in a self-sealing tire is to be removed in a single operation (iii) comprises an element for adjusting the height of the sealant removing element to accommodate different tire diameters and / or an element for adjusting the width of the sealant removing element to accommodate different tire.

3. A self-sealing tire recycling apparatus in accordance with claim 1 or 2 additionally comprising a motor or actuator designed to rotate either the tire or the sealant removing element while the other of said tire or the sealant removing element is stationary (iv) while self-sealing tire sealant removal apparatus is removing the sealant from the tire.

4. A self-sealing tire recycling apparatus in accordance with claim 1, 2 or 3 wherein the apparatus additionally comprises an element for controlling the peeling angle selected from one or more of a roller or plate.

5. A self-sealing tire recycling apparatus in accordance with claim 1, 2, 3 or 4 wherein element (iv) is designed to operate the self-sealing tire sealant removal apparatus (iii) manually, electrically, pneumatically hydraulically, acoustically or by way of a mixture comprising two or more thereof.

6. A self-sealing tire recycling apparatus in accordance with any preceding claim wherein the roller, mandrel or screw has a slot for easier attachment and removal of sealant from a silicone self- sealing tire.

7. A method of recycling self-sealing tires with the self-sealing tire recycling apparatus described herein by taking a self-sealing tire which comprises a tread having an inner and outer surface and sidewalls on opposite sides of said tread which sidewalls are spaced apart at a regular spacing and which has a layer of silicone self-sealing tire sealant on the inner surface of the tread; optionally placing said self-sealing tire on or in support (i), attaching a tire spreading means (ii) having tire engaging elements which engage the sidewalls on the opposite sides of the tire tread and transfer and fix said sidewalls in a spread position in which the tire sidewalls are spaced further apart than their regular spacing; inserting the self-sealing tire sealant removal apparatus having a means of controlling the dimensions thereof (iii) into the tire and adjusting same to fit the dimensions of the layer of silicone self-sealing tire sealant; using the means of rotating self-sealing tire sealant removal apparatus relative to a stationary tire means (iv) to rotate the self-sealing tire sealant removal apparatus (iii) relative to a stationary tire to remove the layer of silicone self-sealing tire sealant from the inner surface of the tread; and collecting the removed silicone self-sealing tire sealant, optionally with (v) the element for collecting removed silicone self-sealing tire sealant from a self-sealing tire comprising at least one of (a’) a container with one side open or a moving conveyor belt to receive the removed sealant; and (b’) a vacuum sucking device.

8. A method of recycling self-sealing tires in accordance with claim 7, wherein apparatus (iii) is designed to make initial contact with a coating overlap in the layer of silicone self-sealing tire sealant to initiate peeling for sealant removal.

9. A method of recycling self-sealing tires in accordance with claim 7 or 8 wherein the layer of silicone self-sealing tire sealant to be removed from the self-sealing tire is (I) provided with a liner to aid peeling the sealant from the tire without breaking the sealant or (II) provided with a luminescence agent or (III) Both (I) and (II) above.

10. A method of recycling one or more self-sealing tires in accordance with claim 7, 8 or 9 wherein the layer of silicone self-sealing tire is recycled by depolymerization, pyrolysis, mechanical means, or a mixture thereof.

11. A method of recycling self-sealing tires in accordance with claim 7, 8, 9 or 10 wherein subsequent to removing the layer of silicone self-sealing tire sealant from the tire, reinforcing wires, reinforcing fibres or both made from one or more of metals, polymers, and / or glass are removedfrom the tire tread and / or the tire tread is recycled by shredding, grinding, cryogenic crushing, pyrolysis, and / or microwave techniques.

12. A method of recycling one or more self-sealing tires in accordance with claim 7, 8, 9, 10 or 11 wherein the cured self-sealing tire silicone sealant is the cured product of a condensation curable self-sealing tire silicone sealant composition comprising (i’) at least one condensation curable silyl terminated polymer having at least one, typically at least two hydroxyl functional groups per molecule; (ii’) a cross-linker selected from the group of • silanes having at least 2 hydrolysable groups, alternatively at least 3 hydrolysable groups per molecule group; and / or • silyl functional molecules having at least 2 silyl groups, each silyl group containing at least one hydrolysable group, and (iii’) a condensation catalyst selected from the group of titanates and / or zirconates; wherein (i’), (ii’) and (iii’) are not stored together in a single part, characterized in that the molar ratio of total silicon bonded-hydroxyl groups to total hydrolysable groups is between 0.5: 1 and 2:1 using a silane containing cross linker or 0.5:1 to 10 : 1, using silyl functional molecules containing crosslinker and the molar ratio of catalyst M-OR functions to the sum of moisture present in the composition, as determined in accordance with ISO 787-2:1981, and total silicon bonded hydroxyl groups is between 0.01:1 and 0.6:1, where M is titanium or zirconium and R is a monovalent, primary, secondary or tertiary aliphatic hydrocarbon group.

13. Use of a self-sealing tire which comprises a tread having an inner and outer surface and sidewalls on opposite sides of said tread which sidewalls are spaced apart at a regular spacing and which has a layer of silicone self-sealing tire sealant on the inner surface of the tread; which layer of silicone self-sealing tire sealant has at least one of :- a coating overlap in the layer of silicone self-sealing tire sealant, a liner applied to the layer of silicone self-sealing tire sealant; and a luminescence agent in or on the layer of silicone self-sealing tire sealant; to assist in the removal of the layer of silicone self-sealing tire sealant from the inner surface of the tire tread in a method of recycling self-sealing tires in accordance with any one of claims 7, 8, 9, 10, 11 or 12.

14. Recycled rubber and recycled silicone sealant obtained as products of the method of any one of claims 7, 8, 9, 10, 11 or 12 from a self-sealing tire.