A method and system for recycling rubber from rubber-containing products

Abstract

The present disclosure relates to a method or system for recycling rubber from a rubber containing waste product while simultaneously enabling the retention of molecular bonding properties in the recycled rubber at a quality similar to that of Virgin Rubber and addresses at least some of the issues associated with methods of recycling rubber containing products known to the inventor. The present method or system allows the reclaimed rubber to retain the natural properties of rubber, thereby making the reclaimed rubber suitable to be reused in manufacturing useful or higher quality by-products that traditionally cannot be achieved. With respect to tyres, this method utilises various novel techniques that enable all parts of the tyre to be reclaimed. Another benefit of this method or system is that it is environmentally and commercially sound, in that the utilisation of this method will reduce the amount of natural rubber harvested from rubber trees.

Description

[0001] A METHOD AND SYSTEM FOR RECYCLING RUBBER FROM RUBBER-CONTAINING PRODUCTS

[0002] PRIORITY CLAIM

[0003] This application claims the benefit of the filing date of United States Provisional Patent Application Serial No. 63 / 507,962, filed June 13, 2023, for “A METHOD AND SYSTEM FOR RECYCLING RUBBER FROM RUBBER-CONTAINING PRODUCTS,’’ the disclosure of which is hereby incorporated herein in its entirety by this reference.

[0004] TECHNICAL FIELD

[0005] The present disclosure relates to the field of recycling. Particularly, the present disclosure relates to the field of recycling tyres and other rubber containing waste products. More particularly, the present disclosure relates to the reclamation of useful commodities from waste products that contain rubber. Most particularly, the present disclosure relates to a method of reclamation of useful commodities from tyres.

[0006] BACKGROUND

[0007] Any reference to background art herein is not to be construed as an admission that such art constitutes common general knowledge in Australia or elsewhere.

[0008] Basic rubber compounds contain natural and / or synthetic rubber. Rubber is utilized in many everyday products (such as tyres). The major components of tyres are natural latex and synthetic rubber, mineral oils, carbon black, vulcanizing agents, accelerators and silica fillers (among other variable additives). The tyre industry consumes over 90 percent of the rubber grown (latex produced by trees) and / or manufactured from hydrocarbons (as synthetic Styrene-butadiene rubber SBR).

[0009] Tyres are typically disposed of in landfill because recycling tyres is energy extensive and only a small portion of the tyre is recoverable for use. The recovered materials are typically of inferior quality and cannot be utilized as an alternative to, or replacement for, natural or synthetic rubber (being commonly known as Virgin Rubber). In this regard, recovered rubber from these processes are generally only used as low-grade fdlers in bitumen, cement-based adhesives, or are blended with isocyanate-based adhesives for playgrounds or sports fields.

[0010] Commonly practiced methods to recycle tyres to reclaim rubber results in poor quality reclaimed materials being used in the tyre and rubber industries. The reclaimed rubber granules are only suitable as inexpensive filler materials for short life span products. The ambient shredding / grinding method is currently the most utilised recycling process. This method involves the tyres being dismembered by force and this generates various size rubber granules. This technique has been utilized for several decades and there is currently no efficient or effective method to separate the embedded metal wires and strong synthetic fibres from the reclaimed rubber granules. This results in considerable waste by-products that cannot be reclaimed.

[0011] Similar to the above, cryogenic grinding processes face the same problem of not being able to efficiently and effectively separate all non-rubber waste products from the reclaimed rubber. An additional problem with the cryogenic grinding process is that freezing rubber dehydrates the reclaimed rubber and results in important ingredients being removed from the rubber chains. It has been noticed that cryogenic grinding results in finer reclaimed rubber than other existing methods. However, this is achieved at significantly higher costs and the reclaimed rubber molecules do not re-bond, even if bulked up with virgin rubber compounds. The result of these existing methods of rubber reclamation is that the reclaimed rubber granules can only be used as fillers in bitumen, cement adhesives, or concrete blends; or be used as playground / sports field surfaces and / or as fuel in steel production (due to its calorific heat value and carbon infusion into the steel). Another method of recycling tyres is pyrolysis, which involves heat generation by burning a third portion of tyres in at least partial absence of oxygen. However, during pyrolysis volatiles are released into the atmosphere and the resultant materials (char, syngas and / or oils) are of poor quality. Pyrolysis also results in the production of low-quality oil and oxidized heavy metal laden carbon. The resultant products typically contain heavy metals (such as mercury, beryllium, lead, cadmium, selenium, manganese, zinc, chromium and the like). Additionally, toxic substances such as dioxin, carbon monoxide and sulphur dioxide are exhausted into the atmosphere which is obviously detrimental to the environment, and this method is not an ideal source of “green energy.”

[0012] Ambient methods of recovering rubber from tyres removes the basic constituent oils and additives from the rubber molecules and this makes the recycled rubber an inert granule / powder that is unable to re-bond. Removed oils and additives cannot be reintroduced to the resultant rubber to rectify this issue. It would be advantageous to recycle rubber (such as that in tyres) to obtain a product that (i) retains the natural mineral oils and additives that are present in masterbatch rubber compounds, (ii) can be used as an equivalent to Virgin Rubber in the manufacture of rubber products, and / or (iii) can be vulcanized after it has been reclaimed.

[0013] As mentioned above, the removal of the natural and synthetic oils from the rubber results in rubber granules that lose ability, or some ability, to be bonded. Natural and / or synthetic oils cannot be reintroduced once removed. One process adopted in an attempt to use recycled rubber is to utilise the rubber granules by coating them with adhesive to produce products such as running tracks, playground surfaces or various pavers. However, an issue with this solution is that the adhesive adds further costs to the production of recycling the rubber, the products may be degradable in UV light, and the products are potentially hazardous.

[0014] Three other approaches to add value to the reclaimed rubber granules have been to dissolve / remove the sulfur in order to break apart the vulcanized rubber chains. An approach was the use of various chemicals / solvents and heat to cleave the sulfur from the carbon substrate. This is expensive and environmentally problematic. More importantly, the mechanical properties of elastomeric rubber matrix are compromised during this process. In this regard, the rubber chains cannot regain interfacial adhesion. Only a small portion of this rubber can be blended with virgin rubber.

[0015] Another method is thermomechanical microwave assisted de- vulcanization. One of the drawbacks of this method is that the rubber (by its very nature) is an insulator and nonpolar, and the microwave penetration rate is quite shallow, so the heat applied to the rubber granules to effect hydrothermal reaction has to reach above 200°C. It is postulated that the granules are conveyed / stirred by a mechanical auger. In fact, at around 180-200°C only the carbon portion of the polymer chains absorb the heat, and this causes degradation thereof. Furthermore, some of the liberated sulfur starts to break away from carbon as early as 25 °C and readily bonds with hydrogen, producing hydrogensulfide. This introduces an aging factor to the de-vulcanised rubber. Regeneration of microwave induced devulcanized rubber is greatly compromised, even at low volume use reinforced with virgin rubber compounds.

[0016] Biological de-vulcanisation utilizes microbes to metabolize sulfur. It has been noted that the microbes degrade the organic rubber compound and even the hydrocarbons.

[0017] It would be advantageous to address one or more of the above issues, and / or provide the consumer with a useful or commercial alternative to Virgin Rubber.

[0018] DISCLOSURE

[0019] In a first aspect, although it need not be the only or indeed the broadest aspect, disclosed is a method for recycling rubber from a rubber-containing product including: a) de-beading the rubber-containing product; b) one or more particle size reduction steps; and c) one or more grinding steps; wherein steps a) to c) are maintained at a temperature of below about 100°C.

[0020] In one embodiment, the rubber-containing product is a tyre.

[0021] In one embodiment, steps a) to c) are maintained at a temperature of below about 75 °C, below about 60°C or below ambient temperatures. In a further aspect, disclosed is a system for recycling rubber from a rubbercontaining product comprising: optionally, a de-beading apparatus adapted to remove bead wire from the rubbercontaining product; a segmenting apparatus adapted to reduce the size of the rubber; one or more particle size reducers adapted to further reduce the particle size of the rubber; and one or more grinders adapted to further reduce the particle size of the rubber; wherein the de-beading apparatus, the segmenting apparatus, the one or more size particle reducers and the one or more grinders are adapted to maintain the temperature of the rubber to below about 100°C, to thereby recycle rubber from the rubber-containing product.

[0022] In one embodiment, the rubber-containing product is a tyre.

[0023] In an embodiment, the de-beading apparatus is adapted to maintain the temperature of the rubber to below about 75 °C, below about 60°C or below ambient temperatures.

[0024] In embodiments, the segmented apparatus is adapted to maintain the temperature of the rubber to below about 75 °C, below about 60°C or below ambient temperatures.

[0025] In an embodiment, the segmenting apparatus is adapted to segment the tyres to at least two (2) pieces. In one embodiment, the segmenting apparatus is adapted to segment the tyres into four (4) pieces.

[0026] In one embodiment, the one or more particle size reducers comprises a first particle size reducer and a second particle size reducer. In an embodiment, the one or more particle size reducers comprises a pair of first particle size reducers and a second particle size reducer.

[0027] In one embodiment, the one or more particle size reducers are adapted to maintain the temperature to below about 100°C, below about 75 °C, below about 60°C or below ambient temperatures.

[0028] In one embodiment, the first particle size reducer is adapted to reduce the rubber to a size in the range of about 5cm to about 20 cm, about 5cm to about 15cm, or about 10cm to about 20cm. In an embodiment, first particle size reducer is adapted to reduce the rubber to a size in the range of about 9mm and about 50mm.

[0029] In an embodiment, the second particle size reducer is adapted to reduce the rubber to a size in the range of between about 5 mm and about 9 mm. In one embodiment, the one or more grinders are adapted to maintain the temperature of the rubber to below about 100°C, below about 75 °C, below about 60°C or below ambient temperatures.

[0030] In an embodiment, the one or more grinders comprise a coarse grinder, a fine grinder and an ultrafine grinder. In one embodiment, system comprises a coarse grinder, a fine grinder and a plurality of ultrafine grinders. In some embodiments, the system comprises a coarse grinder, a fine grinder, a first ultrafine grinder, a second ultrafine grinder and a third ultrafine grinder. In an embodiment, an assembly comprises the first ultrafine grinder, a second ultrafine grinder and the third ultrafine grinder.

[0031] In one embodiment, the coarse grinder is adapted to maintain the temperature of the rubber to below about 100°C, below about 75°C, below about 60°C or below ambient temperatures. In an embodiment, the fine grinder is adapted to maintain the temperature of the rubber to below about 100°C, below about 75°C, below about 60°C or below ambient temperatures. In an embodiment, the ultrafine grinder(s) is or are adapted to maintain the temperature of the rubber to below about 100°C, below about 75 °C, below about 60°C or below ambient temperatures.

[0032] In an embodiment, the coarse grinder is adapted to reduce the particle size of the rubber to between about 2mm and about 4mm.

[0033] In one preferred embodiment, the fine grinder is adapted to reduce the particle size of the rubber to between about 0.5mm to about mm, or between about 1mm to about 2mm.

[0034] In an embodiment, the first ultrafine grinder is adapted to reduce the particle size of the rubber to between about 600 microns and about 1mm. In another embodiment, the second ultrafine grinder is adapted to reduce the particle size of the rubber to between about 150 micron and about 600 micron, or between about 300 micron and about 600 micron. In one embodiment, the third ultrafine grinder is adapted to reduce the particle size of the rubber to between about 20 micron and about 110 micron, or between about 20 micron and 104 micron.

[0035] In some embodiments, an assembly comprises the one or more ultrafine grinders.

[0036] In certain embodiments, the system further comprises a compressor or compacter adapted to apply pressure and / or heat to the rubber.

[0037] The various features and embodiments of the present disclosure referred to in the individual sections above and in the description, which follows apply, as appropriate, to other sections, mutatis mutandis. Consequently, features specified in one section may be combined with features specified in other sections as appropriate. Further features and advantages of the subject matter disclosed herein will become apparent from the following detailed description.

[0038] BRIEF DESCRIPTION OF THE DRAWINGS

[0039] To assist in understanding the scope of this disclosure and to enable a person skilled in the art to put the disclosed subject matter into practical effect, embodiments within the scope of the disclosure will be described by way of example only with reference to the accompanying drawings, in which:

[0040] FIG. 1 shows an embodiment of a de-beading apparatus;

[0041] FIG. 2 shows an embodiment of a segmenting or slicing apparatus;

[0042] FIG. 3 shows an embodiment of a first particle size reducer;

[0043] FIG. 4 shows an embodiment of a second particle size reducer; and FIG. 5 shows an embodiment of a coarse grinder; and

[0044] FIG. 6 shows an embodiment of an ultrafine grinding assembly.

[0045] MODE(S) FOR CARRYING OUT THE INVENTION

[0046] Embodiments of the present disclosure reside primarily in a method and / or system for recycling rubber and / or other materials. Accordingly, the assembly, system, apparatus, or method steps have been illustrated in the drawings, showing only those specific details that are necessary for understanding the embodiments of the present disclosure, but so as not to obscure the disclosure with excessive detail that will be readily apparent to those of ordinary skill in the art having the benefit of the present description.

[0047] In this specification, adjectives such as first and second, left and right, and the like may be used solely to distinguish one element or action from another element or action without necessarily requiring or implying any actual such relationship or order.

[0048] Words such as “comprises” or “includes” are intended to define a non- exclusive inclusion, such that an assembly, system, apparatus, or method that comprises a list of elements does not include only those elements but may include other elements not expressly listed, including elements that are inherent to such an assembly, system, apparatus, or method.

[0049] As used herein, the term ‘about’ means the amount is nominally the number following the term ‘about,’ but the actual amount may vary from this precise number to an unimportant degree. As used herein, and set out above, the term ‘Virgin Rubber’ refers to either natural rubber or synthetic rubber that has not yet been utilized in forming products.

[0050] The disclosed subject matter is predicated, in part, on the finding that high quality rubber and / or other components can be reclaimed from used tyres (and other rubber composite products) using the present methodology. In this regard, the high-quality rubber obtained using the present methodology can be reutilised in creating new rubber products and is able to undergo vulcanization. The recycled rubber obtained using the present methodology appears to retain most, if not substantially all, the original qualities of the Virgin Rubber. In one embodiment, the recycled rubber obtained using the present methodology can be used to substitute some, if not all, the Virgin Rubber without a substantial loss of quality.

[0051] The present process has been described in relation to recycling tyres for ease of description. However, it will be appreciated that rubber in the form of another product can be utilized in accordance with the disclosure. For instance, if the rubber product does not comprise bead wires, then the method need not include the de-beading step.

[0052] In an embodiment, the rubber comprises or is vulcanized rubber.

[0053] As mentioned above, tyres contain embedded bead wire or steel wires, synthetic fibres and / or rubber with optional additional reinforcement materials. The present method of recycling tyres includes the step of removing the bead wires from the tyre. In an embodiment, the wire is removed from the sides to avoid excessive heating. The wire can suitably be cleaned and recycled. The wire can suitably be removed by a magnetic separator or other means. It will be appreciated that the majority of bead wire can be removed in this step; however, some metal still remains in the de-beaded tyres encapsulated throughout the tyre tread and this can be removed subsequently (mentioned in more detail hereinafter).

[0054] Additionally, the tyres with the steel wires removed also allows for easy processability in the proceeding steps. This allows the blades in the following steps to maintain their structure and stay sharp for longer.

[0055] Shown in FIG. 1 is an embodiment of a de-beading apparatus. The de- beading apparatus 100 is adapted to remove the bead wires from tyres. Typically, a tyre contains 2 sets of bead wires to provide structural strength and shape thereto. The de-beading apparatus 100 comprises hydraulic arms (not shown) adapted to pull a tyre. The removal of the bead wire also reduces maintenance in subsequent steps due to parts thereof becoming blunt and / or chipped. The de-beading apparatus 100 comprises a de-beading platform 110. The hydraulic arms may include arm 112 connected to hooks 113. The de-beading apparatus comprises a guidepost 111 for the hook adapted to guide the hook. The hook 113 is adapted to engage a tyre and apply a pulling pressure thereon. The de- beading apparatus 100 comprises a wall 120 having one or more slots 121 adapted to allow the hook 113 therethrough. The hook is suitably connected to the hydraulic arm by a cable 114. The de-beading apparatus 100 comprises one or more controls. The control suitably comprises a hand control 131 and / or foot control 132. In an embodiment, the de-beading apparatus 100 comprises a hinged wall in front of the wall 120 to inhibit (e.g., to prevent) rubber segments from being pulled through.

[0056] In use, tyres are attached to the hook 113 and the hydraulic arms 112 pull the bead wire through the hinged wall and the horizontal slot 121. The bead wire physically cuts through the rubber edge of the tyre to separate itself. The de-beaded tyre then remains outside of the de-beading apparatus 100 while the bead of the tyres is pulled through onto the de- beading platform 110. The bead can then be recycled, and the de-beaded tyres can be conveyed to the segmenting or slicing apparatus 200.

[0057] In an embodiment, the one or more slots 121 are of different sizes. In this regard, the one or more slots may contain a first slot adapted to allow a hook therethrough, and a second and / or third slot spaced apart from the first slot. The second and / or third slot are sized to allow the bead wire to travel therethrough and ‘shaves’ or removes a substantial amount, if not all, of the rubber attached to the wires. In the event that there is a blockage of the slot, the bead wire may break. In this event, the hand control 131 and / or foot control 132 can be utilized to mitigate the risk of this occurring. Alternatively, the hydraulic arms 112 may be adapted to cease pulling if a predetermined pressure is detected to avoid breaking the bead wire.

[0058] It is postulated that the removal of the bead wire from the tyre removes a conduit of heat therefrom. In this regard, it is postulated that bead wire heats up quickly as the tyre undergoes friction and can exacerbate the problem of high temperatures. This heat is then absorbed by the rubber (as mentioned in more detail hereinafter). It is postulated that the removal of the steel wire alleviates this issue. In an embodiment, the tyre is a truck tyre. Truck tyres typically do not contain fibres, the absence of which makes them easier to process. The de-beaded tyres are then segmented. In one embodiment, the segmentation step comprises a slicing step. During the segmentation step, the de-beaded tyres are segmented to at least 2 pieces. In a preferred embodiment, the de-beaded tyres are segmented into four (4) segments. The removal of a substantial portion of the bead wire allows for the segmentation step to be completed without any generation of heat.

[0059] In an embodiment, the de-beading apparatus is adapted to maintain the temperature of the rubber below about 75°C, below about 60°C or below ambient temperatures.

[0060] Shown in FIG. 2 is an embodiment of a segmenting or slicing apparatus 200. The segmenting or slicing apparatus 200 comprises a frame and / or support 210. The segmenting or slicing apparatus 200 comprises one or more slicing edges 220. In the embodiment shown, the segmenting or slicing apparatus 200 comprises four slicing edges 220. In one embodiment, the slicing edges 220 comprise a serrated edge. It is postulated that the serrated edge assists in cutting a tyre as they assist in diminution of the tyre. In this regard, it is postulated that the serrated edge pierces the tyre and as a result the tyre ruptures. Furthermore, it is postulated that this reduces shear pressure on the rubber and prevents unnecessary heating thereof. In one embodiment, the one or more slicing edges are orientated 90° from an adjacent slicing edge. In an embodiment, the segmenting or slicing apparatus 200 comprises four slicing edges.

[0061] The segmenting or slicing apparatus 200 further comprises a surface 230 having one or more slots 231 adapted to receive a respective slicing edge. In one embodiment, the one or more slots are orientated 90° from an adjacent slot. In one embodiment, the surface 230 comprises 4 slots. In one embodiment, the surface is a reinforced surface adapted to receive and resist the pressure of the one or more slicing edges. In one embodiment, the surface comprises a reinforced metal plate. The segmenting or slicing apparatus 200 further comprises a hydraulic arm 240 connected to the one or more slicing edges 220. The hydraulic arm is adapted to apply pressure to the one or more slicing edges 220 such that they are pushed through the one or more slots 231. A tyre placed on the surface 230 are suitably segmented by the one or more slicing edges 220 and thus segment the tyres into smaller and more consistent pieces. The tyre segments are then conveyed to a first size reducer.

[0062] The segmenting apparatus provides a more consistent size which is particularly advantageous when being processed in the following steps or devices. Further bead wires or metal contained in the segmented tyres may be suitably removed therefrom. In this regard, the steel wires can be removed utilizing a magnetic separator.

[0063] In one embodiment, the segmenting or slicing apparatus is a hydraulic segmenting or slicing apparatus. The sliced tyres provide a more consistent feedstock to the grinders. Sliced tyres (by the shape thereof) are more easily captured by the blades of the grinders and this prevents bottlenecks.

[0064] De-beaded tyres are also easier to segment or slice. Additionally, the segmenting apparatus also generates less heat than a shredding apparatus.

[0065] In embodiments, the segmented apparatus is adapted to maintain the temperature of the rubber to below about 100°C, below about 75°C, below about 60°C or below ambient temperatures.

[0066] The segmented tyres are conveyed to a first size reducer. In an embodiment, the first size reducer is a shredder. The first size reducer subjects the segmented tyres to a first particle size reduction step. The first particle size reduction is to a size in the range of about 5cm to about 20 cm, about 5cm to about 15cm, or about 10cm to about 20cm.

[0067] The first particle size reducer can also remove the steel wire or metal from the tyres. The wires can act in a knife-wire manner to liberate themselves from the rubber. This allows them to be easily removed by magnetic separation.

[0068] Shown in FIG. 3 is an embodiment of a first size reducer. The first size reducer 300 comprises a feed inlet 310 adapted to receive segmented or sliced tyres. The first size reducer 300 further comprises a plurality of shredding plates 320 connected to motor 330. The shredding plates 320 suitably shred the segmented tyres to a smaller shredded size. The tyres in the process are suitably expelled into a catchment volume 340. The shredding plates 320 are suitably adapted to rotate in different directions to reprocess the tyres. In one embodiment, the shredding plates 320 are adapted to revolve in one direction for x times / revolutions and then adapted to revolve in the opposite direction for x times. In one embodiment, x is any integer. In one embodiment, x is 6. It will be appreciated that x can be any integer. This process allows for the tyres to be processed multiple times through the shredding plates. The catchment volume is defined by openable arms such that the processed tyres can be accessed. The first size reducer 300 further comprises hydraulics 350 adapted to open the arms. In an embodiment, the shredding plates 320 are spaced out. In one embodiment, the shredding plates 320 are spaced at about 2mm from blades. It will be appreciated that, although de-beaded, the tyres may still have metal in the thread thereof. The metal in conjunction with the process of being pushed through the shredding plates and blades are postulated to utilize the metal in the thread to shave or cut the tyres into a smaller shredded size. The metal can then suitably be removed using a magnetic separator.

[0069] In one embodiment, the first size reducer 300 comprises an inlet 360. The inlet 360 is adapted to allow the flow of a fluid to cool the tyres being processed therein. In an embodiment, the fluid comprises air and / or water. In one embodiment, the first size reducer is adapted to maintain the temperature to below about 100°C, below about 75°C, below about 60°C or below ambient temperatures.

[0070] The time spent in the first size reducer is only a few minutes. The heat that forms during this process dissipates upon the conveyance of the shredded tyre product to the second size reducer.

[0071] In an embodiment, the rubber may be passed through an embodiment of the first particle size reducer. In this regard, this embodiment of the first particle size reduce is similar to that mentioned above with the only except that it is adapted to reduce the particle size to between about 9mm and about 50mm. The sized reduced rubber is then conveyed to a second size reducer.

[0072] The second size reducer further reduces the size of the shredded tyre product. Resident time is not more than a few minutes to ensure that the temperature does not exceed the desired temperature range. Clean rubber granules are discharged therefrom. In one embodiment, the discharged rubber granule size is suitably between about 5 mm and about 9 mm.

[0073] In one embodiment, the second particle size reducer also liberates any remaining steel wire from the tyre. In one embodiment, a magnetic separator can be utilised to remove the remaining steel wire.

[0074] Shown in FIG. 4 is an embodiment of a second size reducer. The second size reducer 400 comprises an inlet 410, a housing 420 having an internal volume, and an outlet 430. In an embodiment, the housing 420 has an internal volume coated with bisalloy. The housing 420 comprises a rotating pulverizer or hammer therein. In an embodiment, the housing 420 comprises blades and a flywheel. The pulverizer or hammer is connected to motor 440. In an embodiment, the motor is an electric motor. The second size reducer 400 further comprises a control screen 450 adapted to control the size of the particles exiting the outlet 430. It will be appreciated that the control screen 450 is adapted to change the fdter to allow only particles of a certain particular size therethrough. In an embodiment, the control screen is adapted to change the fdter between three different sizes. However, it will be appreciated that any number of fdters can be utilized.

[0075] In one embodiment, the second size reducer contains screens used to fdter out fibres. In one embodiment, the separation of fibres in the second size reducer is done using air flotation.

[0076] In one embodiment, the second size reducer is adapted to maintain the temperature to below about 100°C, below about 75°C, below about 60°C or below ambient temperatures.

[0077] The clean rubber is then conveyed to one or more grinders. Heat is dissipated by conveying the clean rubber to the one or more grinders.

[0078] In one embodiment, the one or more grinders is or comprises a hammer mill. The one or more grinders are adapted to reduce the particle size of the rubber sequentially. In this regard, the one or more grinders may suitably comprise a coarse grinder, a fine grinder and at least one ultrafine grinder.

[0079] The rubber granules from the second size reducer 400 are then conveyed to a coarse grinder. Shown in FIG. 5 is an embodiment of the coarse grinder 500. The coarse grinder 500 comprises an inlet 510 adapted to receive the processed tyre from the second size reducer and an outlet 520. The coarse grinder 500 comprises at least two grinding discs 530 adapted to reduce the particle size of the rubber from the second size reducer 400. In one embodiment, the coarse grinder 500 comprises hydraulics 540. In an embodiment, the coarse grinder 500 comprises frame work 550.

[0080] In one embodiment, the coarse grinder is adapted to maintain the temperature of the rubber to below about 100°C, below about 75°C, below about 60°C or below ambient temperatures.

[0081] It will be appreciated that the fine grinder and ultrafine grinder function in a similar fashion to the coarse grinder, with the main exception being that the fine grinder is adapted to further reduce the particle size, and the ultrafine grinder is adapted to even further reduce the particle size of the rubber.

[0082] In embodiments, each grinder, being the course, fine and ultrafine grinders, is adapted to rub the rubber granules. In this regard, each grinder rotates and squeezes the rubber granules such that the action of particle size reduction is achieved through rubbing of the rubber granules against one another. This is different from typical methods of slicing or grinding the rubber granules.

[0083] In one embodiment, the coarse grinder is adapted to reduce the particle size of the rubber. Clean rubber granules are discharged therefrom. In an embodiment, the discharged rubber granule size from the coarse grinder is between about 2mm and about 4mm.

[0084] The rubber granules are then passed through a fine grinder adapted to reduce the rubber granules to a particle size, in the preferred embodiment, of between about 0.5mm to about 8mm. In one embodiment the rubber particle size is reduced to a size of between about 1mm to about 2mm.

[0085] In one embodiment, the fine grinder is adapted to maintain the temperature of the rubber to below about 100°C, below about 75°C, below about 60°C or below ambient temperatures. The fine grinder is adapted to maintain the temperature at the desired temperature range. The rubber is then transferred to one or more Ultrafine grinders.

[0086] In one embodiment, the rubber may then be passed through one or more additional ultrafine grinders, each adapted to reduce the rubber to the desired micron size. The one or more additional ultrafine grinders are each adapted to maintain the temperature at the desired temperature range. In one embodiment, the one or more additional ultrafine grinders are each adapted to reduce the final size of the rubber particle to between about 20 micron to about 600 micron.

[0087] In one embodiment, the one or more additional ultrafine grinders are each adapted to maintain the temperature of the rubber to below about 100°C, below about 75 °C, below about 60°C or below ambient temperatures.

[0088] It will be appreciated that the rubber particles can be passed through a plurality of ultrafine grinders to achieve the desired particle size. In this regard, if a fine rubber is desired then the rubber can be passed through several ultrafine grinders with gradual reduction of particle size. Alternatively, if a more coarse rubber is desired then the rubber can be passed through fewer or no Ultrafine grinders.

[0089] In one embodiment, the one or more grinders comprise a coarse grinder, a fine grinder, a first ultrafine grinder, a second ultrafine grinder and a third ultrafine grinder.

[0090] In an embodiment, the first ultrafine grinder is adapted to reduce the particle size of the rubber to between about 600 microns and about Imn. In another embodiment, the second ultrafine grinder is adapted to reduce the particle size of the rubber to between about 150 micron and about 600 micron, or between about 300 micron and about 600 micron. In one embodiment, the third ultrafine grinder is adapted to reduce the particle size of the rubber to between about 20 micron and about 110 micron, or between about 20 micron and 104 micron.

[0091] Shown in FIG. 6 is an embodiment of an assembly 600 comprising a plurality of the ultrafine grinders. The Ultrafine grinder 600 comprises an inlet 610 adapted to receive the rubber granules from the fine grinder . The Ultrafine grinder 600 comprises at least one ultrafine grinder 630a, 630b, 630c (three in the preferred embodiment, shown in FIG. 6).

[0092] In one embodiment, each particle size reduction grinder 630 comprises at least two grinding discs (not shown) adapted to reduce the particle size of the rubber.

[0093] In one embodiment, the ultrafine grinders are vertically offset from adjacent grinders. Each grinder comprises an inlet and an outlet. Each ultrafine grinder is adapted to further reduce the size of the rubber exiting the above ultrafine grinder. Each ultrafine grinder is adapted to only allow rubber of a particular size to the outlet thereof. The exiting rubber powder is then allowed to be gravity fed to the inlet of the adjacent and subsequent ultrafine grinder. This orientation allows the exiting rubber of each grinder to cool down prior to being subsequently ground to a smaller particle size.

[0094] In embodiments, the system comprises two or more course, fine, or ultrafine, grinders. In an embodiment, the system comprises 2, 3, 4, 5, ... or ‘n’ course, fine, or ultrafine, grinders.

[0095] In one embodiment, the system comprises 2 first size reducers, a second size reducer, a coarse grinder, a second grinder and three ultrafine grinders.

[0096] The resultant product is a fine rubber powder of between about 50 microns to about 600 microns. In one embodiment, the rubber powder is aerated and can then suitably be compressed and / or shaped in moulds of various sizes to produce rubber products. In another embodiment, the rubber powder is aerated and can be blended with Virgin Rubber and compressed and / or shaped in moulds of various sizes to produce rubber products. In one embodiment, the micronized rubber is compressed at about 60 tonnes to 250 tonnes to eliminate all air from the rubber powder and any gaps between the particles. The rubber powder is suitably subjected to heat. In one embodiment, the heat source is suitably provided by either electrical, gas, or steam. In an embodiment, the micronized rubber is subject to compression and / or heat for between about 0.5 hours to about 2 hours. In an embodiment, the micronized rubber is also heated to a temperature of about 200°C. In an embodiment, the micronized rubber is heated to a temperature of no greater than about 250°C. In one embodiment, the micronized rubber is heated to a temperature of between 200°C and about 250°C.

[0097] This results in the rubber powder being molecularly rebonded.

[0098] In a preferred embodiment, the temperature of this method is maintained at below about 145°C, below about 100°C, below about 75°C, below about 60°C, between about 0°C and about 100°C, between about 0°C and about 80°C, or between about 60°C to 80°C.

[0099] Molecules or rubber contain long chains of polymers. It is believed that these chains stick together by electrostatic bonds and these entangled chains results in the elasticity in the rubber. It is postulated that heat results in the rubber being more susceptible to oxidation and can even disintegrate the electrostatic bonds.

[0100] It is postulated that, as the temperature is maintained at a lower temperature, the issue of tyre fumes due to heat is significantly reduced or alleviated. As the temperature does not exceed a predetermined threshold, little to no tyre fumes are released which is advantageous from both an industrial process and environmental viewpoint. These fumes are also typically the natural or synthetic oils that are added as additives. As such, the synthetic oils and natural oils are not removed from the present recycled rubber.

[0101] Furthermore, it is believed that the excessive mechanical forces will further exacerbate this issue with heat. The present disclosure allows for the rubber to be carefully treated to retain quality thereof without excessive mechanical forces. Furthermore, testing suggests that Sulphur bonds in vulcanized rubber also stay intact.

[0102] The results from testing the rubber obtained from the present methodology suggest that they retain the ability to re-bond. Furthermore, the rubber obtained from the present methodology also has elasticity, duro hardness, UV rating and wear and tear that substantially matches the performance of Virgin Rubber.

[0103] In an embodiment, the disclosed subject matter encompasses recycled rubber obtained using the present methodology mentioned hereinabove, or utilizing the system mentioned hereinabove.

[0104] The present disclosure provides a viable solution to the reclamation or recycling of rubber from rubber-containing products, such as tyres. In this regard, the present disclosure provides a commercially viable solution for the reclamation of rubber from rubbercontaining substances in an environmentally friendly manner. The present disclosure provides a means for recycling rubber containing waste product into useful useable reclaimed resources. These reclaimed recourses can be utilized in the manufacture of new products. Furthermore, a flow on effect of the present disclosure is that the natural plant habitat (rubber plants) is preserved, and socio-economic benefits can be observed.

[0105] In one embodiment, the recycled rubber obtained from this method is clean and uncontaminated by foreign materials. In an embodiment, the recycled rubber obtained from this method has a uniform particle size. In embodiments, the recycled rubber obtained from this method is undamaged or substantially undamaged at a molecular level.

[0106] Experimental Section

[0107] Testing

[0108] The inventors completed a number of tests utilizing various components or elements of the prior art methods.

[0109] Test 1 - Effect of heat on rubber

[0110] Heat transfer processes involve composite systems. Measurements were taken during processing off-cut rubber and identified heat to be convection sourced, generated by the equipment shredding / grinding of rubber. This was surprising, as it is known that rubber is a good thermal insulator. However, under processing stress, the rubber reached high temperatures. Smoke was observed, which demonstrated that volatile components thereof were being driven away from the rubber. These volatiles are critical added ingredients of oils, accelerators, vulcanizing activators, and anti -degrading agents. Reduction in any or all of these volatiles, even in small quantities, degrades the molecular chains opening them up to oxidation.

[0111] It is postulated that long-term heat exposure during standard recycling processing can cause oxidation and thermal aging of rubber, which contributes to deteriorated and weakened performance of reclaimed rubber products.

[0112] This finding identified that heat would be a problem for extracting quality rubber.

[0113] Test 2 - Effect of heat on tyres as they become a heatsink.

[0114] Studies were carried out on processing tyres in order to identify distinctiveness, residence times, and characteristics of tyres (or parts thereof), in standard recycling machines. In many cases, the heavy duty bead wires were left in the tyres when they were processed by shredders. Steel wires make up approximately 12% of the weight of a typical tyre. Fibres also make up approximately 12% of the weight of a typical tyre. Standard recycling processes feed numerous tyres into a hopper at once. This results in quantities of gravel, sand, and other foreign material (non-rubber products) being shredded with the tyres. All of these non-rubber products mix with the reclaimed ground rubber, thereby contaminating the end product. No matter how many different machines deal with the reduction, small size wires, fluffy fibres, and other non-rubber products contaminate the reclaimed ground rubber. This demonstrates that the use of existing methods or systems of rubber reclamation cannot guarantee quality uncontaminated product for re-use. Additionally, a more problematic impediment to producing valuable reclaimed rubber is caused by the heat generated during the processing through the use of heavy duty machines. Despite the fact that rubber is a good thermal insulator, the metal from the tyres would readily increase in temperature during shredding; rasping; and grinding. As rubber is made up of a large quantity of carbon and additional carbon black (33% by weight) the generated heat is transferred to the rubber. It should be noted that the tread section of the tyres is made up of synthetic rubber (polybutadiene rubber) which hardens when heated, while the natural rubber forming the side walls of the tyre (polyisoprene rubber) softens when heated. As such, a rise in temperature results in the deterioration of the molecular integrity of the rubber. Test pieces of tyre were subjected to the temperatures they would experience in the standard processes to evaluate the resistance of rubber to heat.

[0115] Within the rubber industry the actual molecular chain scission and crosslinking steps are often unknown, as is the effect of heat or stress (caused by pressurized machines) on the de-coupling (or weakening) of the intricate rubber molecular chains. As the composition of the rubber including concentration of accelerators, activators, and fillers, varies for each different tyre type, it is quite impossible to standardise. The measurable outcome of “damaged rubber” is only seen when the reclaimed rubber granule (fine powder 30# for instance) is used to manufacture a product.

[0116] It is postulated that carbon in rubbers is vulnerable to chain scission. This is a known fact in the field of polymers with electron donating compounds. In this regard, electrons more easily move in hot products. The rubber has to be inhibited (e.g., prevented) from becoming a heat-sink.

[0117] Test 3 - Rheology test on rubber under stress

[0118] Tyres are subjected to a number of processing operations, and this results in the polymer chains being stressed. The effect of the heat generated by the machines on the rubber elevates the swelling and / or shrinkage thereof. The problem also causes destruction of the chains as the differences of natural rubbers softening, and synthetic rubbers hardening (although these chains are interlinked within a tyre as it acts like ONE molecule). Once the rubber molecular chains are stressed, especially in a heated state, degradation commences. It was found that heat and stress on the molecular structure of the rubber within the tyre, which is reinforced by metallic wires and equally strong nylon - nylon6 - polyester fibres, has a strong influence on the rheological behavior of polymeric rubber compounds. Test 4 - Degradation of rubber by oxidation

[0119] Most elastomers undergo rubber degradation over time and the most common rubber deterioration causes are exposure to light, oxygen (ozone) and heat. The molecular changes brought about by these environmental conditions can significantly impact the mechanical properties of the reclaimed rubber during recycling. Antioxidants are added to rubber compounds in order to prevent or slow down oxidational degradation. If these additives are driven away during the recycling process by the generated heat, the rubber molecules are more prone to oxidating effects. During the life cycle of a tyre, they compress and flex continuously. This natural action squeezes the protective substances (antioxidants; oils, etc.) to the surface of the rubber and easily evaporate.

[0120] A typical antioxidant: 3, 5-di-tert-butyl-4-hydroxyhydrocinnamate

[0121] Another form of degradation of rubber by burning in reduced oxygen level is the pyrolysis process. This mode of recycling is a rarely practised method to deal with a waste tyres. The process involves utilising (whole tyres and / or shredded tyres) to be burned in a partially enclosed container. About a third of the volume of rubber (together with fibres) is consumed (burned with oxygen present) to generate the necessary heat to distil off various hydrocarbons (oils). Another by-product of this process is residual carbon. It is important to note that pyrolysis has a number of issues when relating to waste tyres. One problem is uncontrollable pollution (or very expensive mitigation on an ongoing basis). Another problem is that rubber is destroyed in the process. Yet another problem is that the resulting by-products are contaminated (by dangerous chemicals and heavy metals) rendering them useless. Test 5 - Crosslinking characteristics of polymer chains

[0122] The inventor has found few reliable methods to study the cross- linking, branching properties of rubber. In this regard there seems to be few studies in rubber literatures. A tyre can be considered a single large molecule. The complexity of this product has created a lot of uncertainty even to manufacturers of tyres. The inventor has observed that in hot, stressed, and / or strained rubber the carbon-sulfur link was weakened. This allowed oxidative degradation of the molecules, rendering the reclaimed rubber granules or powder simply an inert, vulcanizable dust.

[0123] Test 6 - Dehydration within the molecular chains of rubber compound

[0124] Molecular singularity is one of the most important mechanical properties of rubber, especially when it is used for tyres. This makes the rubber more resistant to damage (e.g., virtually indestructible) and very hard to recycle. On the technical part, when this property is disrupted by heat or prolonged pressure, stress or chemical processing, or microwave processing, invariably vital ingredients are removed. Accordingly, a problem to be solved is to identify which part (if any) of the rubber compound forming a tyre can be removed without rendering the reclaimed rubber useless. The inventor postulates that other recycling techniques known to the inventor alter the molecular chains of the rubber in one form or another and to obtain useful reclaimed rubber all parts of the original rubber compound must be retained. There is a law internationally adhered to regarding the life-cycles of tyres, namely: 15-20% of loss of tyre weight. This means that after -80-85% of tyre tread wears, the tyre has to be replaced. Yet this disposed tyre will take more than one hundred years to start breaking down. Accordingly, to prevent the toxic buildup of waste rubber products, especially tyres, a processing technique that enables the reclaimed rubber to retain all components of the original rubber compound would be desirable. Test 7 - Changes of molecular (Dalton) weight of broken crosslinks along the polymeric chains.

[0125] An individual rubber molecule can have a molecular weight of 100,000 to 1,000,000 Daltons (about 1.7 x 10'19gram to 1.7 x 10'18gram) with junctures along the polymeric chains. This chain has a memory. This is why rubber has elastic properties and can be stretched before returning to its resting form. These chains in natural format (this both apply to natural and synthetic rubbers) break down or apart. Temperature fluctuations, oxygen, ozone, chemicals, and radiation are the usual causes of this degradation. To prevent (or minimize) this degradation (and have a longer life cycle of the polymeric chains) vulcanizing agents were discovered and found to achieve this purpose. The best-known chemical that acts as a vulcanising agent is sulfur. Sulfur bonds with the carbon part of the molecule, joining the rubber molecules together. In addition, a number of other ingredients are also incorporated into a rubber compound. Once this compound is processed by vulcanization a tyre then becomes one molecule. If an improper method of recycling is conducted the molecular chains are broken, and the degradation process recommences, resulting in the rubber losing its most unique and valuable property, being its elasticity and being safe to use. Present Testing

[0126] The temperatures or various steps of the present process were monitored: Testing

[0127] Several samples were prepared for testing the tensile strength of rebonded rubber obtained utilizing the present methodology. The Ian Wark Research Institute conducted tests using a Hounsfield Tensiometer Instrument. The results of these tests on several disc rubber and rubber samples are shown below in Graph 1 :

[0128] Graph 1 - Force vs extension data for several disc rubber and rubber samples obtained using the present methodology. The above description of various embodiments within the scope of the present disclosure is provided for purposes of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the disclosure to a single disclosed embodiment. As mentioned above, numerous alternatives and variations to the presently disclosed subject matter will be apparent to those skilled in the art of the above teaching. Accordingly, while some alternative embodiments have been discussed specifically, other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art. Accordingly, this disclosure is intended to embrace all alternatives, modifications and variations ofthe presently disclosed subject matter that have been discussed herein, and other embodiments that fall within the spirit and scope of the above described subject matter.

Claims

AMENDED CLAIMS received by the International Bureau on October 22, 2024 (22.10.2024)What is claimed is:

1. A system for recycling rubber from a rubber containing product comprising: a de-beading apparatus adapted to remove bead wire from the rubber containing product; a segmenting apparatus adapted to reduce the size of the rubber- containing product; one or more particle size reducers adapted to further reduce the particle size of the rubber; and one or more grinders adapted to further reduce the particle size of the rubber; wherein the de-beading apparatus, the segmenting apparatus, the one or more size reducers, and the one or more grinders are adapted to maintain the temperature of the rubber to between about 75°C and about ambient temperature, to thereby recycle rubber from the rubber containing product.

2. The system of claim 1, wherein the segmented apparatus is adapted to maintain the temperature of the rubber to about 60°C.

3. The system of any one of the preceding claims, wherein the segmenting apparatus is adapted to segment the tyres to at least two (2) pieces.

4. The system of any one of the preceding claims, wherein the one or more size reducers are adapted to maintain the temperature to about 60°C.

5. The system of any one of the preceding claims, wherein the one or more size reducers comprises a first particle size reducer and a second particle size reducer.

6. The system of claim 5, wherein the first particle size reducer is adapted to reduce the rubber to a size in the range of about 5cm to about 20 cm.

7. The system of claim 5 or 6, wherein the second particle size reducer is adapted to reduce the rubber to a size in the range of about 5mm to about 50mm, or about 9mm to about 50mm, or about 5mm to about 9mm.

8. The system of any one of preceding claims, wherein the one or more grinders are adapted to maintain the temperature of the rubber to about 60°C.

9. The system of any one of the preceding claims, wherein the one or more grinders comprise a coarse grinder, a fine grinder and an ultrafine grinder.

10. The system of any one of the preceding claims, wherein the one or more grinders comprise a coarse grinder, a fine grinder, a first ultrafine grinder, a second ultrafine grinder and a third ultrafine grinder.

11. The system of any one of claims 9 or 10, wherein the coarse grinder is adapted to reduce the particle size of the rubber to between about 2mm and about 4mm.

12. The system of any one of claims 9 to 11, wherein the fine grinder is adapted to reduce the particle size of the rubber to between about 0.5mm to about mm, or between about 1mm to about 2mm.

13. The system of any one of claims 9 to 12, wherein the first ultrafine grinder is adapted to reduce the particle size of the rubber to between about 600 microns and about 1mm.

14. The system of any one of claims 9 to 13, wherein the second ultrafine grinder is adapted to reduce the particle size of the rubber to between about 150 micron and about 600 micron, or between about 300 micron and about 600 micron.

15. The system of any one of claims 9 to 14, wherein the third ultrafine grinder is adapted to reduce the particle size of the rubber to between about 20 micron and about 110 micron, or between about 20 micron and 104 micron.

16. A method for recycling rubber from a rubber-containing product including: a) de -beading the rubber containing product; b) one or more steps of size reduction; andc) one or more grinding steps; wherein steps a) to c) are maintained at a temperature of between about 75°C and about ambient temperature.

17. The method of claim 16, wherein steps a) to c) are maintained at a temperature of about 60°C.

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