Modular intermittent coating systems and methods for producing polymer-coated substrates

Abstract

The present application describes an intermittent method for coating solid substrates, including fertilizer tablets, pharmaceutical tablets, nutraceutical products, and other shaped or particulate articles on a horizontal conveyor loop. The system comprises a pair of parallel conveyors, one or more cavity plates configured to retain the substrates, a plurality of activity stations arranged for sequential coating operations, and a pair of cavity plate transfer units for transferring cavity plates between conveyors. Coated solid substrates and apparatuses for coating sold substrates are also described herein.

Description

Title: Modular Intermittent Coating Systems and Methods for Producing Polymer-Coated SubstratesRelated Applications

[0001] The present application claims priority to: United States Provisional Application Number 63 / 701 ,498 entitled IMPROVED METHOD OF MANUFACTURING POLYMER COATED FERTILIZERS IN AN INTERMITTENT COATING PROCESS, filed September 30, 2024; United States Provisional Application Number 63 / 701 ,569 entitled IMPROVED METHOD OF COATING SOLID SUBSTRATES ON AN ENDLESS HORIZONTAL CONVEYOR SYSTEM, filed September 30, 2024; and United States Provisional Application Number 63 / 784,346 entitled METHODS OF MANUFACTURING A POLYMER COATED FERTILIZER HAVING A DEFINED AREA OF RELEASED, filed April 7, 2025, the contents of each of which are hereby incorporated by reference in their entirety.Technical Field

[0002] The present application is directed to coating systems and, more specifically, modular intermittent coating systems and methods of producing polymer-coated substrates.Background

[0003] Conventional batch drum coating techniques are limited in throughput and coating precision. Conveyor-based systems with cavity plates fixed to a chain conveyor improved upon these methods but remain inflexible. Adding new coating layers or process steps requires major redesign, and servicing one station interrupts the entire line.

[0004] The technical problem is to provide a conveyor-based coating system with greater flexibility, adaptability, and scalability while minimizing downtime.Summary

[0005] The accordance with a broad aspect, the present application described a modular horizontal conveyor system for coating solid substrates, including but not limited to fertilizer granules, fertilizer tablets, pharmaceutical tablets, nutraceutical products, natural seeds and other solid particulate or shaped articles.

[0006] In at least one embodiment, the apparatus, systems and methods described herein provide a coating module comprising a pair of parallel conveyors, one or more cavity plates configured to receive and retain substrates, a plurality of activity stations, and a pair of cavityplate transfer units. A cavity plate is advanced along the first conveyor system and sequentially halted beneath the activity stations, where predetermined operations are performed on the substrates housed within the cavities. Upon completion of processing within the module, the cavity plate is transferred horizontally to the parallel conveyor by means of a cavity plate transfer unit for additional processing.

[0007] In accordance with a broad aspect, a method of producing polymer-coated substrates using an intermittent substrate coating system is described herein. The method includes: advancing and halting a substrate holder at a plurality of activity stations mounted along the length of the conveyor system, each activity station being configured to perform one or more coating-related operation on the substrates; and performing the following coating-related operations at the activity stations: feeding solid substrate into the substrate holder at a feeding station; applying a first polymer film at a first film application station; heating and wrapping the first polymer film around the substrates at a first coating station to form partially coated substrates; severing and collecting portions of the first film not adhered to the substrates at a first excess film cutting and collection station; inverting the partially coated substrates at a flipping station to expose uncoated surfaces thereof; applying a second polymer film at a second film application station; and heating, softening, and wrapping the second polymer film around the partially coated substrates at a second coating station to form fully coated substrates; thereby producing a polymer-coated substrate comprising at least two polymer film layers including a sealing layer.

[0008] In at least one embodiment, the method includes performing at least one of the following coating-related operations at the activity stations: severing and collecting portions of the second film not adhered to the substrates at a second excess film cutting and collection station; applying a liquid polymer coating at a liquid coating application station and drying the applied coating at an associated drying station; applying a wax overcoat layer at a wax overcoating station; introducing perforations into the coating at a micro-perforation station; and collecting the coated substrates at a collection station.

[0009] In at least one embodiment, the conveyor system includes one or more parallel conveyor frames, the one or more parallel conveyor frames comprising at least two conveyor frames arranged side by side.

[0010] In at least one embodiment, a pair of plate transfer units is positioned at opposite ends of the parallel conveyor frames, the plate transfer units being configured to transfer the coatingcavity plates between the conveyor frames when the plurality of coating cavity plates are detachably mounted on the conveyor frames.

[0011] In at least one embodiment, the plate transfer units comprise rotary, linear, or pick- and-place transfer mechanisms configured to transfer the coating cavity plates between conveyor frames in an endless loop.

[0012] In at least one embodiment, each of the plurality of activity stations is independently mountable, removable, or reconfigurable along the conveyor frames.

[0013] In at least one embodiment, the first coating station comprises a heating element and a wrapping mechanism configured to wrap the heat-softened film around the substrates.

[0014] In at least one embodiment, the excess film cutting station comprises a cold punching die, a hot punching die, a hot air knife, and a vacuum system in combination, configured to sever and remove portions of the polymer film not adhered to the surface of the substrate.

[0015] In at least one embodiment, the flipping station comprises an apparatus configured to invert the partially coated substrates within the same cavity of a cavity plate or into a different cavity of a different cavity plate.

[0016] In at least one embodiment, the liquid coating application station comprises a liquid polymer applicator selected from a foam pad, fibrous roller, spray nozzle, or porous applicator, and a drying mechanism selected from heating, vacuum, infrared irradiation, ultraviolet irradiation, or forced air.

[0017] In at least one embodiment, the wax overcoating station is configured to apply one or more wax layers, the wax layers comprising natural wax, synthetic wax, or blends thereof.

[0018] In at least one embodiment, the micro-perforating station comprises one or more needles, pins, or laser perforators configured to generate controlled perforations in the coating.

[0019] In at least one embodiment, the collection station comprises an automated ejector system or receptacle for receiving the coated substrates after processing.

[0020] In at least one embodiment, the activity stations are arranged in series along each conveyor frame to provide sequential multi-layer coating of the substrates.

[0021] In at least one embodiment, the apparatus is modular and configured such that additional conveyor frames or activity stations may be added to scale production capacity or enable additional coating operations.

[0022] In accordance with another broad aspect, an apparatus for coating solid substrates is described herein. The apparatus includes: one or more parallel conveyor frames arranged side by side; a plurality of coating cavity plates mounted on the conveyor frames; a pair of plate transfer units positioned at opposite ends of the parallel conveyor frames, the plate transfer units being configured to transfer the coating cavity plates between the conveyor frames; and a plurality of activity stations mounted on one or more of the conveyor frames, the activity stations being configured to perform predetermined activities on the solid substrates, wherein one or more of the activity stations includes at least one of: a feeding station configured to feed the solid substrates into the coating cavity plates; a film unwinding station configured to apply one or more coating films; a film coating station configured to heat and wrap the heat-softened coating films around the solid substrates; an excess film cutting station configured to sever and collect portions of film not adhered to the substrates; a flipping station configured to invert the partially coated substrates; a liquid coating and drying or curing station configured to apply a liquid coating and dry or cure the coating; a wax overcoating station configured to apply a wax overcoat onto the coated substrates; a micro-perforating station configured to perforate the coating; and a collection station configured to collect the coated substrates.

[0023] In at least one embodiment, the one or more parallel conveyor frames comprise at least two conveyor frames arranged side by side.

[0024] In at least one embodiment, the coating cavity plates are detachably mounted on the conveyor frames.

[0025] In at least one embodiment, the plate transfer units comprise rotary, linear, or pick- and-place transfer mechanisms configured to transfer the coating cavity plates between conveyor frames in an endless loop.

[0026] In at least one embodiment, each of the plurality of activity stations is independently mountable, removable, or reconfigurable along the conveyor frames.

[0027] In at least one embodiment, the film coating station comprises a heating element and a wrapping mechanism configured to wrap the heat-softened film around the substrates.

[0028] In at least one embodiment, the flipping station comprises an apparatus configured to invert the partially coated substrates within the same cavity of a cavity plate or into a different cavity of a different cavity plate.

[0029] Th In at least one embodiment, the liquid coating and drying or curing station comprises a liquid polymer applicator selected from a foam pad, fibrous roller, spray nozzle, or porous applicator, and a drying mechanism selected from heating, vacuum, infrared irradiation, ultraviolet irradiation, or forced air.

[0030] In at least one embodiment, the wax overcoating station is configured to apply one or more wax layers, the wax layers comprising natural wax, synthetic wax, or blends thereof.

[0031] In at least one embodiment, the micro-perforating station comprises one or more needles, pins, or laser perforators configured to generate controlled perforations in the coating.

[0032] In at least one embodiment, the collection station comprises an automated ejector system or receptacle for receiving the coated substrates after processing.

[0033] In at least one embodiment, the activity stations are arranged in series along each conveyor frame to provide sequential multi-layer coating of the substrates.

[0034] In at least one embodiment, the apparatus is modular and configured such that additional conveyor frames or activity stations may be added to scale production capacity or enable additional coating operations.

[0035] In accordance with another broad aspect, a polymer-coated substrate is described herein. The polymer-coated substrates has: a solid substrate; a polymer coating covering substantially the entire surface of the solid substrate, the polymer coating having a water vapor transmission rate (WVTR) between 0.1 g / m2day and 2000 g / m2day; and one or more perforations extending through the polymer coating, wherein the polymer-coated substrate is configured to release the substrate substantially through the perforations over an extended period of time.

[0036] In at least one embodiment, the solid substrate comprises a fertilizer tablet, pharmaceutical core, biocide pellet, detergent tablet, water treatment tablet, or agrochemical pellet.

[0037] In at least one embodiment, the first polymer layer and the second polymer layer each comprise a polymer selected from the group consisting of aliphatic polyesters, including butnot limited to polylactic acid (PLA), polyglycolic acid (PGA), poly(lactic-co-glycolic acid) (PLGA), polycaprolactone (PCL), poly(butylene succinate) (PBS), poly(butylene succinate-co- adipate) (PBSA), poly(butylene succinate-co-terephthalate) (PBST), poly(butylene adipate-co- terephthalate) (PBAT), polyethylene succinate) (PESu), polypropylene succinate) (PPSu), poly(butylene carbonate) (PBC), poly(trimethylene carbonate) (PTMC), polyethylene carbonate) (PEC), and copolymers thereof; polyhydroxyalkanoates (PHAs), including poly(3- hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(3- hydroxyhexanoate) (PHHx), poly(3-hydroxyoctanoate) (PHO), poly(3-hydroxydodecanoate) (PHD), poly(4-hydroxybutyrate) (P4HB), and copolymers or blends thereof; starch-based polymers, including thermoplastic starch (TPS) and starch blended with polyesters such as PBAT or PCL; cellulose-based polymers, including regenerated cellulose, cellulose acetate, cellulose acetate butyrate, carboxymethyl cellulose, hydroxypropyl cellulose, and ethyl cellulose; protein-based biopolymers, including zein, soy protein isolate, wheat gluten, gelatin, and collagen; polysaccharide-based biopolymers, including chitosan, alginate, pectin, pullulan, xanthan gum, gellan gum, and hyaluronic acid; and other biodegradable polymers, including polyethylene oxide), degradable polyethylene glycol (PEG) derivatives, polyvinyl alcohol (PVA), polyethylene furanoate) (PEF), poly(butylene furanoate) (PBF), degradable polyurethane, silk fibroin. In some embodiments, the coating films may comprise water-soluble polymers that dissolve under controlled aqueous conditions to facilitate nutrient release. Suitable examples include polyvinyl alcohol (PVA), available in both cold-water soluble and hot-water soluble grades.

[0038] In at least one embodiment, at least one of the first or second polymer layers has a thickness in the range of 10 pm to 2000 pm.

[0039] In at least one embodiment, the polymer-coated substrate includes a wax overcoat layer disposed over the first polymer layer, the second polymer layer, or both.

[0040] In at least one embodiment, the polymer-coated substrate includes a liquid-applied barrier polymer coating disposed over the first polymer layer, the second polymer layer, or both.

[0041] In at least one embodiment, the one or more perforations have diameters in the range of 1 pm to 500 pm.

[0042] In at least one embodiment, the one or more perforations are arranged in a predetermined pattern to control diffusion of water or active ingredients.

[0043] The polymer-coated substrate of any one of claims 29 to 36, wherein the perforations are introduced by laser perforation, micro-needle puncturing, or mechanical punching.

[0044] In at least one embodiment, the polymer layers are configured to provide a controlled release of the substrate contents when exposed to water, soil, or biological media.

[0045] In at least one embodiment, the solid substrate has a largest dimension in the range of 2 mm to 200 mm.

[0046] In at least one embodiment, the polymer-coated substrate is configured for use in soil, hydroponic, or soilless growing systems.

[0047] These and other features and advantages of the present application will become apparent from the following detailed description taken together with the accompanying drawings. It should be understood, however, that the detailed description and the specific examples, while indicating preferred embodiments of the application, are given by way of illustration only, since various changes and modifications within the spirit and scope of the application will become apparent to those skilled in the art from this detailed description.Brief Description of the Drawings

[0048] For a better understanding of the various embodiments described herein, and to show more clearly how these various embodiments may be carried into effect, reference will be made, by way of example, to the accompanying drawings which show at least one example embodiment, and which are now described. The drawings are not intended to limit the scope of the teachings described herein.

[0049] Figure 1 illustrates a three-dimensional line drawing of a modular conveyor apparatus (700) configured for coating operations, shown without activity stations.

[0050] Figure 2 illustrates, in a perspective view, a horizontal conveyor system having a plurality of activity stations mounted along the conveyor.

[0051] Figure 3 illustrates a detailed view of a section of a conveyor timing belt system (703) in accordance with at least one embodiment described herein.

[0052] Figure 4 illustrates a sectional view of a conveyor frame (701) according to at least one embodiment described herein.

[0053] Figure 5 illustrates, in a side cross-sectional view, a one-layer coating module comprising a plurality of activity stations mounted on a frame (701), according to at least one embodiment described herein.

[0054] Figure 6 illustrates a flow chart of a modular coating system comprising a plurality of activity stations arranged along a conveyor system, according to at least one embodiment described herein.

[0055] Figure 7 illustrates a cross-sectional view of a coating station comprising a heating station and a vacuum suction station, according to at least one embodiment described herein.

[0056] Figure 8 illustrates a cross-sectional view of a vacuum-forming coating process according to at least one embodiment described herein.

[0057] Figure 9 illustrates a cross-sectional view of an excess film cutting station (600) according to at least one embodiment described herein.

[0058] Figure 10 illustrates a flipping apparatus (800) configured to invert partially coated substrates (103) according to at least one embodiment described herein.

[0059] Figure 11 illustrates a flipping apparatus (800) configured to invert partially coated substrates (103) according to at least one embodiment described herein.

[0060] Figure 12 illustrates a flipping apparatus (800) configured to invert partially coated substrates (103) according to at least one embodiment described herein.

[0061] Figure 13 illustrates a flipping apparatus (800) configured to invert partially coated substrates (103) according to at least one embodiment described herein.

[0062] Figure 14 illustrates, in a top view, a support plate-based conveyor module 701 according to at least one embodiment described herein.

[0063] Figure 15 shows a cross-sectional illustration of a coating apparatus for solid substrates (100a) utilizing a conveyor system and support plate (900), according to at least one embodiment described herein.

[0064] Figure 16 shows a cross-sectional illustration of a coating apparatus for solid substrates (100a) utilizing a conveyor system and support plate (900), according to at least one embodiment described herein.

[0065] Figure 17 illustrates a cross-sectional view of a coated substrate (121) comprising a solid core material encapsulated within a polymeric coating layer, the coating layer being provided with a perforation to facilitate controlled passage of moisture or active agents therethrough, according to at least one embodiment described herein.

[0066] Figure 18 illustrates a cross-sectional view of a coated substrate (121) comprising a solid core material encapsulated within a polymeric coating layer. The polymeric coating layer includes a perforation and the perforation is subsequently covered by an additional overcoating layer of polymer material, according to at least one embodiment described herein.

[0067] Figure 19 illustrates a cross-sectional view of a coated substrate (121) comprising a solid core material encapsulated within a polymeric coating layer, the coating layer being provided with a thinned region in the coating.

[0068] Figure 20 illustrates a micro-perforation activity station according to at least one embodiment described herein.

[0069] Figure 21 illustrates a perspective view of a film application station (350) according to at least one embodiment described herein.

[0070] Figure 22 illustrates a cross-sectional view of a standalone intermittent coating apparatus configured for laboratory- scale operation.

[0071] Figure 23 illustrates a cross-sectional view, according to at least one embodiment described herein, of a standalone scale coating apparatus 1000, which may be configured for producing small batch quantities of polymer-coated substrates, according to at least one embodiment described herein.Detailed Description

[0072] Various systems, apparatus, compositions and processes will be described below to provide an example of one or more embodiments. No embodiment described below limits any claimed embodiment and any claimed embodiment may cover systems, apparatus, compositions or processes that differ from those described below. The claimed embodiments are not limited to systems, apparatus, compositions or processes having all of the features of any one system, apparatus, composition or process described below or to features common to multiple or all of the systems, apparatus, compositions or processes described below. It is possible that a system, apparatus, composition or process described below is not anembodiment of any claimed embodiment. Any embodiment disclosed below that is not claimed in this document may be the subject matter of another protective instrument, for example, a continuing patent application, and the applicants, inventors or owners do not intend to abandon, disclaim or dedicate to the public any such embodiment by its disclosure in this document.

[0073] The present disclosure provides a method utilizing a horizontal conveyor loop for advancing cavity plates through sequential coating stations, thereby enabling continuous and efficient coating operations.

[0074] The present disclosure also provides a modular coating apparatus and method wherein activity stations are independently mountable and reconfigurable on conveyor modules, allowing scalability and customization of coating processes.

[0075] The foregoing objectives are illustrative and not intended to limit the scope of the disclosure, which encompasses variations, modifications, and equivalents as set forth in the claims.

[0076] For the purposes of the present disclosure, the following terms are defined according to certain embodiments. Unless otherwise indicated, these definitions are intended to describe particular embodiments and are not to be construed as limiting the scope of the invention.

[0077] As used herein, the term “conveyor system "refers to a system or apparatus configured to transport or carry solid substrates from one point to another point along a defined path. The conveyor system may include, without limitation, a belt conveyor, chain conveyor, rotary indexing table, vacuum-forming cavity rollers, or other intermittent or continuous substrate transfer mechanism adapted to advance and halt the substrates at predetermined activity stations.

[0078] As used herein, the term “substrate holder” refers to a component of the conveyor system that is configured to receive, support, and retain one or more solid substrates during transport along the conveyor path. The substrate holder may comprise one or more cavities, recesses, or pockets shaped to correspond to the geometry of the solid substrates to prevent displacement thereof during advancing and halting of the conveyor. The substrate holder may further include clamping, suction, or magnetic elements to secure the substrates in place, and may be formed from heat-resistant or polymer-compatible materials to withstand subsequent coating operations. A coating cavity plate, as described in the present disclosure, represents one exemplary type of substrate holder.

[0079] Horizontal Conveyor System: A conveyor arrangement in which solid substrate holders are transported in a substantially horizontal orientation while maintaining an upward-facing position.

[0080] Intermittent Coating Process: A coating process wherein cavity plates mounted on a conveyor system are subjected to cyclical motion comprising alternating periods of movement and stoppage.

[0081] Modular System: A conveyor-based assembly comprising independent modules, each with one or more activity stations performing specific operations on substrates or coatings. Modules are structurally and functionally independent and may be connected in series to create an expandable and reconfigurable system.

[0082] Activity: An operation performed on a substrate or coating during the coating process, including but not limited to feeding, coating, excess film trimming, coating perforating, substrate flipping, film heating, vacuum forming, liquid drying, or aligning, cavity plate buffering. Activities may be executed individually or sequentially by dedicated activity stations.

[0083] Activity Station: A structural or functional unit along a conveyor system configured to perform a specific activity.

[0084] Cycle Time: The predetermined period for which the conveyor is halted to allow completion of an activity, typically defined by the longest activity time measured under single plate operation, ensuring synchronization of all stations.

[0085] Timing belt: refers to a belt having teeth or grooves formed along its inner surface, which are configured to engage with a correspondingly toothed indexing pulley. The timing belt is operatively connected to a servo-driven motor via the pulley, enabling controlled advancement and halting of the belt with high positional accuracy in response to programmed signals.

[0086] Coating-Cavity Plate (Cavity Plate): A plate with cavities open at both ends, each cavity defined by side walls and a shoulder or step portion near the lower surface to retain a substrate while maintaining through passage.

[0087] Through-Cavity: A cavity or aperture extending entirely through the plate with no stepped section or closed bottom, which may be circular, oval, polygonal, or irregular in shape.

[0088] Flipping / Flipped: The re-orientation of a substrate relative to a cavity plate to expose an uncoated portion; a flipped substrate has been rotated or inverted from its original orientation.

[0089] Flipping Apparatus: A device or assembly configured to perform flipping operations during the coating process.

[0090] Matching Cavities: Cavities formed in separate plates at identical centre-to-centre spacing such that their centres coincide upon alignment.

[0091] Partially-Coated Substrate: A substrate having a continuous coating layer applied only to part of its surface.

[0092] Fully-Coated Substrate: A substrate completely encapsulated on all sides by one or more continuous coating layers, leaving no exposed surface.

[0093] The apparatuses, systems and methods described herein address the aforementioned technical problem by introducing a modular horizontal loop conveyor system in which activity stations are independently mountable, removable, and reconfigurable.

[0094] The intermittent coating systems described herein offer several advantages over conventional continuous coating systems. By advancing and halting the substrate holder at a plurality of activity stations, the systems described herein enable precise alignment and accurate positioning of substrates during each coating-related operation. This precision allows for improved control over film application, perforation, trimming, and wrapping, thereby ensuring uniform coating thickness and consistent quality across individual substrates.

[0095] Another advantage is the modularity and flexibility of the systems. Each station can be independently configured to perform a distinct function, such as feeding, heating, cutting, flipping, or inspection, which facilitates adaptation of the process to different substrate types and coating requirements. This modular approach provides for easy reconfiguration of the production line to accommodate new product designs or formulations without substantial modification to the entire apparatus.

[0096] The intermittent mode of operation also improves quality control. Since substrates remain stationary during each operation, in-line inspection mechanisms can be integrated to monitor coating integrity, detect defects, or measure film thickness in real time. Defectivesubstrates can be selectively removed without disrupting the process flow, thereby reducing waste and enhancing overall reliability.

[0097] Furthermore, intermittent coating is particularly well suited for substrates with irregular geometries or fragile characteristics. The ability to halt and manipulate substrates, including flipping or reorienting them between stages, enables complete encapsulation and multi-layer film application that may be difficult to achieve using continuous processes. In addition, stationary trimming and excess film collection during the halted phase minimizes material waste and reduces the risk of wrinkles, tearing, or misapplication of films.

[0098] Collectively, these advantages result in a coating process that is more versatile, precise, and adaptable than continuous systems, making it suitable for both industrial-scale production and specialized applications requiring complex coating architectures.

[0099] The Applicant of the present application also owns PCT Patent Application No. PCT / CA2021 / 050944 entitled COATED SUBSTRATES AND METHODS OF MAKING SAME filed on July 9, 2021 , the contents of which are hereby incorporated by reference in its entirety, and which claims priority to each of: United States Provisional Patent Application No. 63 / 050,344 filed July 10, 2010; United States Provisional Patent Application No. 63 / 062,491 filed August 7, 2020; and United States Provisional Patent Application No. 63 / 116,940 filed November 23, 2020, and the contents of each of which are also incorporated by reference herein in their respective entireties.

[0100] Turning now to the Figures, Figure 1 illustrates a three-dimensional line drawing of a modular conveyor apparatus (700) configured for coating operations, shown without activity stations according to at least one embodiment described herein. The modular conveyor apparatus (700) comprises a pair of parallel conveyor frames (701 , 702) operatively connected by plate transfer units (713, 713a). Each conveyor frame (701 , 702) is constructed from a plurality of longitudinal beams (709), cross beams (710), and vertical support legs (712).

[0101] The parallel conveyor frames (701 , 702) are structurally arranged in a manner that permits synchronized transport of a plurality of cavity plates along their respective lengths. The plate transfer units (713, 713a) are disposed at both terminal ends of the apparatus to facilitate transfer of cavity plates between the parallel frames.

[0102] The modular design of the apparatus (700) enables extension by connecting additional pairs of parallel conveyor frames in series thereby allowing scalable length adjustment of theconveyor system. The modular nature further permits a user to connect a plurality of such frames as required for production throughput.

[0103] Each conveyor frame (701 , 702) is configured to receive a plurality of activity stations (as shown in Figure 1) mounted along the length of the frame. The activity stations comprise individual functional units designed to perform discrete coating-related operations on cavity plates conveyed by the apparatus. Also illustrates a plate transfer apparatus according to at least one embodiment described herein. The plate transfer apparatus is configured to move coating cavity plates (105) between a first conveyor frame (701) and a second conveyor frame (702). The apparatus comprises a vacuum suction plate (715) provided with a plurality of suction cups (not shown), the suction plate (715) being mounted on a linear screw mechanism (714) and guided by parallel support bars (717, 718). The suction plate (715) is actuated by a servo drive motor (716), whereby the suction plate travels linearly along the screw axis to carry a cavity plate between adjacent conveyor frames.

[0104] At the end of the first conveyor frame (701), a plate pushing station (not shown) is positioned to cooperate with the suction plate (715). Upon detection of a cavity plate (105), pneumatic cylinders of the pushing station elevate the cavity plate upward into engagement with the suction cups. When engaged, vacuum is applied to secure the cavity plate to the suction plate (715). The linear screw (714) then displaces the suction plate across the support bars, transferring the cavity plate from the first conveyor frame (701) to the second conveyor frame (702). Upon arrival, the suction plate (715) releases the cavity plate onto a pusher plate (not shown) of the second conveyor frame (702), which subsequently lowers the cavity plate (105) into position on the conveyor timing belt between cleats.

[0105] In another embodiment, the transfer of cavity plates (105) between conveyor frames (701 , 702) is accomplished by a gantry robotic arm configured to pick up a cavity plate from the first conveyor frame (701) and deposit it onto the second conveyor frame (702).

[0106] In yet another embodiment, a curved transfer conveyor system (as shown in Figure 2) is employed to facilitate transfer of cavity plates (105) between conveyor frames. Such curved transfer conveyors are well known in the art of material handling, comprising a belt spanning the width of the frame and driven by a servo motor. In this embodiment, cavity plates (105) are advanced from the end of the first conveyor frame (701) onto the curved conveyor belt, guided along a programmed transfer path, and deposited at the entry point of the second conveyor frame (702), where the plates are aligned and positioned on the conveyor timing belt (703) between the cleats (704).

[0107] Figure 2 illustrates, in at least one embodiment, a perspective view of a horizontal modular coating system (2000). The system includes a first conveyor frame (2001) and a second conveyor frame (2002), a plurality of activity stations (2003) arranged along the conveyor path, a plurality of cavity plates (2004), a plurality of servo motors and drives (2005), a first cavity plate transfer unit (2006), and a second cavity plate transfer unit (2007). In operation, the cavity plates (2004) are conveyed along the system, and at each activity station (2003) a designated coating related activity is carried out on substrates positioned within the cavity plates. The conveyor system functions in an endless horizontal loop along the conveyor frames (2001 , 2002), thereby permitting sequential processing at multiple modular stations.

[0108] In certain embodiments, the cavity plate transfer sections may comprise planetary transfer units configured to rotate cavity plates along a curved trajectory while maintaining alignment during transfer. In another embodiment, the curved transfer sections may comprise rotary turntables adapted to receive cavity plates from one modular conveyor unit, rotate the plates through a defined angle, and deliver them to an adjacent modular conveyor unit. In a further embodiment, the curved transfer sections may comprise arc-shaped belt-driven modules configured to convey cavity plates along a continuous loop. The selection of transfer section type may be based on space optimization, alignment precision, or throughput requirements of the modular conveyor system.

[0109] Figure 3 illustrates a detailed view of a section of a conveyor timing belt system (703) in accordance with at least one embodiment described herein. The conveyor timing belt (703) is arranged along a conveyor frame (701) and is adapted to receive and transport coating cavity plates (105) positioned thereon. The timing belt (703) advances the cavity plates (105) sequentially along the length of the conveyor frame (701), thereby transferring the cavity plates between successive activity stations.

[0110] The conveyor timing belt (703) further maintains positional alignment of the cavity plates (105) during transport, ensuring accurate registration of the substrates housed within the cavities of the plates with respect to the activity stations. In certain embodiments, the timing belt (703) may include cleats, projections, or engagement features configured to secure the cavity plates (105) in a fixed orientation while the plates advance through the conveyor system.

[0111] The conveyor timing belt (703) comprises a plurality of cleats (704) integrally formed or fixed onto the belt structure (as shown in Figure 3). Each cavity plate (105) is positioned between two adjacent cleats (704), which serve to restrain the cavity plate and maintain positional stability during conveyance.

[0112] The timing belt (703) is driven by a pulley (705) mounted on a shaft (706) (as shown in Figure 3). The shaft (706) is operatively connected to a programmable servo motor and drive system, enabling precise indexing and controlled movement of the cavity plates (105) from one processing station to another.

[0113] In one embodiment, the load-bearing portion of the timing belt (703), upon which the cavity plates (105) rest, is supported by a channel (708). The channel (708) may include a smooth polished surface or a plurality of roller bearings to minimize friction between the timing belt (703) and the support channel (708) during belt movement.

[0114] The timing belt (703) may be fabricated from high-temperature resistant synthetic materials, optionally reinforced with steel wires to provide enhanced tensile strength. In an alternative embodiment, the conveyor system employs a metallic chain-based timing belt comprising flat platforms for supporting cavity plates. In such embodiments, the pulley (705) may be adapted with sprocket gears to engage the metallic chain structure.

[0115] The design and operation of pulleys, timing belts, and chain-driven conveyors as herein described are well established in the field of material handling and transport systems and are readily adaptable by those skilled in the art to the present invention.

[0116] Figure 4 illustrates a sectional view of a conveyor frame (701) according to at least one embodiment described herein. The conveyor frame (701) comprises a plurality of vertical support legs (712), longitudinal beams (709, 709a), and transverse cross beams (710), which together form a rigid structural framework for supporting conveyor components and activity stations.

[0117] The conveyor frame (701) further comprises an anchor plate (711), which extends along the longitudinal length of the frame and is fastened, such as by bolts, to the support beams (709). The anchor plate (711) provides a mounting interface for securing one or more activity stations to the conveyor frame structure.

[0118] The conveyor frame (701) additionally houses a conveyor timing belt (703) disposed within a support channel (708) (as shown in Figure 7). The timing belt (703) is operatively driven by a pulley (705) mounted on a driving shaft (706), the shaft being coupled to a programmable servo motor and drive system. The servo-controlled operation permits precise indexing and advancement of cavity plates (105) along the conveyor frame (701).

[0119] In an alternative embodiment, the activity stations are not mounted onto the anchor plate (711) but rather supported on independent mounting platforms affixed to the floor adjacent the conveyor frame (701). This configuration allows greater flexibility in equipment layout and minimizes vibration transfer between the conveyor frame and the activity stations.

[0120] Figure 5 illustrates, in a side cross-sectional view, a one-layer coating module comprising a plurality of activity stations mounted on a frame (701), according to an embodiment. The module comprises the frame (701), a plurality of coating cavity plates (105), and a feeding station (200) configured to deliver solid substrates (100) into the cavities of the coating cavity plate (105). The module further comprises a film unwinder and application system (300) including a film roll (301), the film unwinder and application system being configured to unwind and apply a polymer film (101) onto the coating cavity plate (105) carrying the plurality of solid substrates (100) within the cavities (106). A heating station (400) is provided for heat-softening the polymer film (101) to enable coating. A vacuum suction station (500) is disposed beneath a cavity halt position and is operable to draw a vacuum from beneath the solid substrates (100) to wrap the softened polymer film (101) around the substrates. An excess film cutting station (600) is provided to cut away and remove excess portions of the film that do not adhere to the substrates (100), thereby freeing partially coated substrates (103) from the applied film layer. An optional secondary vacuum suction station (500a) may be disposed beneath the cavity plate halt position at cutting station 600 to assist in lifting the partially coated substrates (103) from the cavities and in facilitating separation of excess film. The module further comprises a flipping station (800) to invert the partially coated substrates (103) such that the uncoated portions of the substrates are exposed, a waste film collection system (806) for collecting film remnants not attached to the substrates, and an optional partially coated substrate collection station for transferring and collecting the partially coated substrates into a collection receptacle.

[0121] A plurality of modules, either identical or configured for different activities, may be arranged in series, provided that the cavity plates (105) are transferable between the modules. In some embodiments, an individual module may receive partially coated substrates output from a preceding module, while in other embodiments, a module may include an independent feeding station for introducing new substrates. The cavity plates halt for substantially the same duration at each activity station across one or more modules connected in series.

[0122] Figure 6 illustrates a cross-sectional view of a coating activity station comprising a heating station and a vacuum suction station, according to an embodiment. The thermoformingprocess employed within the coating station utilizes heat and vacuum in combination to wrap a heat-softened polymer film (101) around a solid substrate (100).

[0123] The coating activity station comprises a heating station (401) mounted onto an anchor plate (711) of a conveyor frame (701). A pair of thermal baffles (402) is provided to reduce heat dissipation, while a plurality of film-pinning rollers (403) on the opposing sides of the cavity plate, secures the polymer film (101) in place during heating. A coating cavity plate (105) houses the solid substrates (100) within cavities (106), the cavity plate (105) being transported on conveyor timing belts (703, 703a), conveyor timing belt (703 and 703a) is supported by a housing bracket (708 and 708a)(as shown in Figure 6 and Figure 7)

[0124] Positioned directly beneath the cavity plate (105) is a vacuum suction station (500), aligned with the cavities (106) (as shown in Figure 6 and Figure 7). The vacuum suction station (500) comprises a vacuum box (504), a vacuum suction plate (507) affixed to the box (504), and a plurality of substrate-supporting platforms (502) secured to the vacuum plate (507). A plurality of vacuum ports (503) is provided through which suction is applied to draw the softened film (101) around the substrates (100).

[0125] To ensure precise positioning, the vacuum box (504) is provided with alignment pins (509) configured to engage alignment holes (109) in the cavity plate (105) (as shown in Figure 6 and Figure 7). The alignment pins (509) extend slightly above the supporting platforms (502), thereby engaging the cavity plate (105) prior to platform contact and aligning the cavity plate (105) such that each platform (502) is centered beneath a cavity (106).

[0126] The vacuum box (504) is further coupled to a sliding mechanism by a pair of connectors (506, 506a) and guided by a pair of sliding rails (507, 507a). Vertical displacement of the vacuum box (504) is actuated by pneumatic cylinders (505, 505a) mounted beneath the frame (701). The pneumatic cylinders are controlled to deliver precise vertical movement, thereby raising the vacuum box (504) into sealing engagement with the underside of the cavity plate (105). The connectors (506, 506a), in cooperation with the sliding rails (507, 507a), maintain the vacuum box (504) in a substantially vertical orientation during motion (Figure 6 and Figure 7).

[0127] Accordingly, the coating station provides coordinated heating and vacuum suction to form the film (101) around the substrates (100) contained in the cavity plate (105), thereby producing a partially or fully coated substrate.

[0128] Figure 7 illustrates a cross-sectional view of a vacuum-forming coating process according to an embodiment. In this embodiment, a substrate (100) is elevated by a supporting platform (502) such that the substrate (100) is urged into contact with a heat-softened polymer film (101). Vacuum suction is applied through underlying vacuum ports to draw the polymer film (101) around the surface of the substrate (100), thereby conforming the film to the substrate. At this stage, the polymer film (101) remains connected to the surrounding portion of the film while adhering to the surface of the substrate (100). A subsequent processing step in the next activity station is performed to remove or cut away the excess portion of the polymer film (101) that remains connected to the adhered film on the substrate (100), thereby isolating the coated substrate.

[0129] Figure 8 illustrates a cross-sectional view of an excess film cutting station (600) according to an embodiment. The cutting station (600) comprises a cutting plate (601), a plurality of round cutting dies (602), and a vertical movement assembly including actuators (606, 606a) configured to move the cutting plate (601) upward and downward as required. A pair of pinning rollers (603, 603a) is provided to secure the polymer film (101) in position during cutting. The station further comprises a vacuum station (500), substantially identical in construction to that described in earlier embodiments, configured to apply suction so as to pull the film downward while simultaneously retaining the substrates (100) in position.

[0130] The round cutting dies (602) are provided with sharp cutting edges adapted to apply pressure onto the polymer film (101) and thereby sever the excess film portion that remains connected to the partially coated substrate (103). In certain embodiments, the cutting plate (601) is configured as a thermal plate capable of heating the round cutting dies (602) to facilitate the cutting operation. The cutting dies (602) are generally fabricated from high- strength stainless steel and may be provided with non-stick surface coatings so as to minimize adhesion of severed film fragments to the cutting edges.

[0131] Figure 9, Figure 10, and Figure 11 illustrates a cross-sectional view of flipping apparatus (800) configured to invert partially coated substrates (103) in order to expose uncoated portions of their surfaces for subsequent coating, according to an embodiment.

[0132] The flipping apparatus (800) comprises a pair of robotic arms (801 , 802) configured to hold a coating cavity plate (105a). The robotic arms (801 , 802) are capable of five-axis movement including 360-degree rotational motion. Each arm is further equipped with a gripping mechanism adapted to engage one or more objects simultaneously to rotate the gripped objects together through up to 360 degrees.

[0133] Positioned beneath the coating cavity plate 105, is a cavity plate pushing system (803) aligned with a coating cavity plate (105) mounted on a conveyor frame (712, and 712a) (As shown in Figure 9). The pushing system (803) is actuated by a pair of pneumatic cylinders (804, 805), which provide controlled vertical displacement for raising and lowering the pushing plate (803). The pushing plate (803) is further provided with engagement members (803a) enabling it to grasp and support the coating cavity plate (105) containing partially coated substrates (103).

[0134] During operation, upon activation by a sensor, the pushing plate (803) elevates the coating cavity plate (105) carrying the partially coated substrates (103) toward the coating cavity plate (105a) held in an inverted position by the robotic arms (801 , 802). When the plates (105, 105a) are brought into alignment such that their respective cavities are facing one another (as shown in Figure 10), the robotic arms (801 , 802) engage both plates simultaneously and rotate the combined structure approximately 180 degrees. As a result, the cavity plate (105a) is transferred to the lower position while the cavity plate (105) is rotated into the upper position, thereby inverting the substrates (103) into the cavities of the coating cavity plate (105a) (as shown in Figure 11).

[0135] Following the flipping operation, the pushing plate (803) collects the cavity plate (105a) from the robotic arms (801 , 802) and returns it onto the conveyor timing belt (703) for further processing.

[0136] Figure 12 illustrates, in a top view, a support plate-based conveyor module 701 b according to an embodiment. The conveyor module 701 b comprises a conveyor frame 711 b provided with support beams and cross beams. A pair of shafts 706b, 706c is mounted to the frame and operatively connected to a motor 707a for driving the shafts. A conveyor timing belt 703b is positioned around the shafts and is configured to carry a plurality of cleats 704b, which convey a coating cavity plate 105b.

[0137] In one embodiment, a support plate 900 is mounted on the conveyor frame 711 b and secured to both sides of the frame. The support plate is a generally flat structure which may be fabricated from metallic material, non-metallic material, or natural material, or combinations thereof. The support plate comprises platform holes 901 , 901a, and a cut-out region 902. The support plate functions to support solid substrates (100a) and to prevent solid substrates from falling through the through-cavities 106b of the coating cavity plate 105b.

[0138] In another embodiment, the coating cavity plate 105b comprises a plurality of through- cavities 106b. The through-cavities are substantially cylindrical and do not include a bottom step. Accordingly, the presence of the support plate 900 beneath the coating cavity plate is necessary to retain substrates within the through-cavities. The support plate (as shown in Figure 12) extends across substantially the entire width and length of the conveyor frame between the shafts 706, 706a, and is aligned such that the platform holes 901 , 901a correspond with the through-cavities 106a.

[0139] In certain embodiments, the cavity holes 901 , 901 a are sized and positioned to allow passage of a vacuum platform (502a, as shown in Figures 13 and 14). When the coating cavity plate halts at a vacuum station (500a) and heating station (400a), the vacuum platform (502a in Figure 13) may be actuated upward through the platform holes (901) to lift and hold the substrates (as shown in Figure 13 and 14)

[0140] In one embodiment, the absence of a bottom step in the through-cavities 106a provides a larger cavity volume, thereby enabling more effective vacuum suction. This results in enhanced coating uniformity. In another embodiment, the support plate 900 is provided with a cut-out region 902 disposed near an end of the conveyor frame, through which coated substrates 104a are permitted to discharge into a collection bin.

[0141] In certain embodiments, the support plate system offers reduced manufacturing costs compared to stepped cavity plates, since through-cut cavities require fewer machining operations. In yet another embodiment, the support plate system enables substrate manipulation during the coating process by incorporating resistance features.

[0142] In one embodiment, the support plate 900 includes a resistance patch or resistance bar configured to induce flipping of partially coated substrates. The resistance patch may comprise a knurled surface, a roughened surface, or a shallow cavity recessed into the support plate. In operation, as a substrate slides over the support plate, the resistance patch momentarily impedes forward movement, inducing the substrate to roll. This rolling action causes the substrate to rotate about its axis, thereby flipping a partially coated substrate to expose the uncoated side for further coating.

[0143] In certain embodiments, the resistance patch comprises a shallow cavity into which the substrate partially falls. A subsequent lateral force applied by the cavity wall urges the substrate into a flipping motion. In yet another embodiment, the resistance patch is dimensioned according to the geometry of the substrate. Round substrates may roll morereadily, whereas pillow-faced substrates such as fertilizer briquette may require deeper resistance patches. Smaller substrates may be more easily flipped, while larger substrates may require greater resistance or more pronounced cavity features.

[0144] In certain embodiments, the substrates may comprise tablets that are introduced into the substrate-holding cavities in a vertical orientation, resting on their curved or round side. After the application of a partial polymer coating, the tablets may be mechanically repositioned, for example by rolling or tilting, so that they rest on their flat side. This reorientation exposes the previously uncoated portion of the tablet surface, thereby allowing subsequent coating operations to be performed until the substrate is fully encapsulated. Such vertical feeding followed by rolling may be implemented in either a cavity plate-based conveyor system or a cavity roller-based system and may be accomplished by an integrated rolling or reorientation mechanism associated with the conveyor or roller apparatus.

[0145] In one embodiment, the support plate 900 is fabricated with a smooth and polished surface to enable substrates to slide with minimal friction. In certain embodiments, designated resistance areas are deliberately roughened or recessed to achieve controlled rolling of the substrates. The resistance patches are configured such that substrates rotate when they come in contact with the resistance patch but do not continue rolling beyond the desired orientation.

[0146] In yet another embodiment, the resistance patch may be interchangeable or adjustable to accommodate substrates of varying sizes and shapes. In certain embodiments, the resistance feature may be integrated into the structure of the support plate, while in other embodiments it may be a removable insert fixed to the support plate.

[0147] Referring now to Figure 13 and 14, there is shown a cross-sectional illustration of a coating apparatus for solid substrates (100a) utilizing a conveyor system and support plate (900), according to at least one embodiment described herein. The apparatus is configured to coat solid substrates (100a) with at least one layer of polymer film (101a) in a controlled and repeatable manner.

[0148] Still referring to Figure 13 and Figure 14, a coating cavity plate (105b) is provided, the plate (110) including a plurality of through-cavities (106b), each dimensioned to receive a corresponding solid substrate (100a). The cavity plate (105b) is conveyed along a conveyor system (701 b as shown in Figure12)) and rests upon conveyor belt 703b (as shown in Figure 12) and is supported by the support plate (900). Substrates (100a) are dispensed into thethrough cavities (111) from a feeding station (200a), and any excess is removed by a scraper (202a), thereby ensuring that each cavity (106b) retains only a single substrate (100a).

[0149] Still referring to Figure 13 and Figure 14, A first polymer film (101a) is applied over the cavity plate (105b) by means of a film dispensing unit (301a). The film (101a) extends across the upper surface of the cavity plate (105b), covering the substrates (100a) contained within the cavities (106b). The cavity plate (105b), together with the film (101a) and substrates (100a), is then advanced toward a heating station (400a) and vacuum suction station.

[0150] Still referring to Figure 13 and Figure 14, At the heating and vacuum suction station (500a), the cavity plate (105b) halts at a predetermined position such that each cavity (106b) is precisely aligned above a platform (502a). The platform (502a) forms part of a vacuum plate (501a) and is configured so that its top surface faces the centre of each cavity (106b). In this position, the substrate (100a) rests upon the platform (502a).

[0151] Referring to Figure 14, As the cavity plate (110) is held in this position, the polymer film (101a) is heat-softened by the heating unit (400a). Once the film (101a) has reached a thermoformable state, the vacuum plate (501a) is actuated upwardly , causing the substrates (100a) to be slightly elevated relative to the cavity plate (110). Simultaneously, a vacuum suction is applied through channels in the vacuum plate (501a). This suction action draws the softened polymer film (101a) downward and around the exposed surfaces of the substrates (100a).

[0152] Still referring to Figure 14, As a result, the polymer film (101a) conforms tightly to the shape of the substrates (100a), thereby producing partially coated substrates. These partially coated substrates (200b) may subsequently advance to additional downstream processing stations, such as a cutting station, a flipping station, or a second film application station , depending on the desired coating configuration.

[0153] Referring to Figure 12, Figure 13, and Figure 14, This embodiment provides several technical advantages. First, the use of the support plate (900) in combination with the vacuum plate (501a) ensures precise alignment of the substrates (100a) within the cavities (106b), thereby enabling a more accurate and repeatable coating due to availability of more area around the platform for vacuum to be pulled specially when very smaller diameter substrates are used and the cavity dimeters are smaller. Second, the method of lifting the substrates (100a) by the platform (502a) while simultaneously applying vacuum suction through the vacuum plate (501a) allows the film (101a) to be thermoformed closely around each substrate(100a). Third, the modular nature of the system permits multiple coating cycles and combinations of films, resulting in the ability to produce multi-layer coatings, partial coatings, or coatings with varied barrier properties. Another advantage of the coating system having cavity plates with through cavities and a support plate system is the collection of substrates after coating, an opening in the support plate 900 allows the coated solid substrates to just fall through the opening into a collection bin eliminating a separate coated substrate collection apparatus.

[0154] Accordingly, the embodiment of Figure 13 and Figure 14 demonstrates a reliable and scalable approach to producing polymer-coated solid substrates (100a), which may include fertilizer tablets, pharmaceutical cores, or other particulate materials requiring controlled release or protective coatings.

[0155] Figure 15 illustrates a cross-sectional view of a polymer-coated substrate (120) according to at least one embodiment described herein. The polymer-coated substrate (120) comprises a shaped solid substrate 115, a polymer coating 117, and a perforation (116) formed in the coating, the perforation being configured to permit controlled ingress of moisture into the substrate and controlled egress of dissolved components therefrom.

[0156] Figure 16 illustrates a cross-sectional view of a shaped polymer coated substrate (121) according to at least one embodiment described herein. The coated substrate (121) comprises a shaped solid substrate (115), a primary polymer coating layer (117) applied around the solid substrate (115), at least one micro-perforation (112) formed in the polymer coating (117), and an overcoating layer (122) disposed on the polymer coating (117).

[0157] Figure 17 illustrates a cross-sectional view of a shaped polymer coated substrate (123) according to at least one embodiment described herein. The shaped coated substrate (123) comprises a shaped solid substrate (115) coated with a polymer coating layer (125). The polymer coating layer (125) includes a thinned-out region (124) formed within its structure. The thinned-out region (124) exhibits a rate of moisture ingress distinct from that of the remainder of the polymer coating (125), thereby enabling controlled tailoring of moisture ingress and subsequent release of active agents through the coating (125).

[0158] Figure 18 illustrates a micro-perforation activity station according to at least one embodiment described herein. The micro-perforation station comprises a micro-perforation plate (128) provided with a plurality of sharp pins (127) integrally formed or affixed as part ofthe plate structure. The pins (127) are oriented toward the surface of coated substrates (115) contained within a cavity plate (126).

[0159] Referring to Figure 18, during operation, when the micro-perforation station detects the presence of the cavity plate (126) positioned beneath the micro-perforation plate (128), a vertical displacement mechanism such as a pair of pneumatic cylinders (not shown) attached to the micro-perforation plate (128) is actuated to advance the micro-perforation plate (128) toward the coated substrates (115). The pins (127) are thereby brought into proximity with the polymer coating (117) on the surface of the substrates (115) and penetrate the coating to form perforations. The perforations are defined by the tip geometry of the pins (127), including their diameter, as well as by the depth of penetration achieved.

[0160] In certain embodiments, the pins (127) are thermally assisted by mounting the microperforation plate (128) onto a heating plate configured to raise the pins to a predetermined temperature, thereby facilitating penetration of the polymer coating (117) and improving perforation consistency.

[0161] Figure 19 illustrates a perspective view of a heating station (450) in accordance with at least one embodiment described herein. The heating station comprises a heating system (454) configured to provide a controlled heat source for raising a polymer film to a desired temperature. One or more baffles (452) are positioned to surround the heater, thereby directing heat toward the film and reducing heat loss to the surrounding environment. A pair of pneumatic cylinders (456, 458) are operatively connected to raise and lower the heating system relative to a conveyor-mounted cavity plate. The station is further supported by a pair of mounting brackets (459) adapted to secure the heating station onto the conveyor frame, thereby enabling integration into a modular coating line.

[0162] Figure 20 illustrates a perspective view of a substrate lifting system (550) according to at least one embodiment described herein. The system comprises a platform plate (551) carrying a plurality of lifting platforms (553). Each lifting platform (553) is dimensioned to engage a corresponding substrate positioned within a cavity of a coating cavity plate and is configured to move the substrate upward and downward in a controlled manner.

[0163] A pair of pneumatic cylinders (554) are mounted on opposite sides of the system and operatively coupled to the platform plate (551). The pneumatic cylinders (554) are configured to actuate vertical movement of the platform plate in response to control signals generated by the system controller. Upon receiving an activation signal, the cylinders drive the platform plateupward or downward by a predetermined displacement length, thereby ensuring accurate substrate positioning.

[0164] In certain embodiments, the substrate lifting system (550) further incorporates one or more suction boxes (504, as illustrated in Figure 7) operatively connected to vacuum ports (504, as illustrated in Figure 7) formed in the platform plate (551). When actuated, the suction elements generate negative pressure through the ports, thereby temporarily securing the substrates against the lifting platforms during vertical displacement.

[0165] In a further embodiment, a movable vacuum box may be mounted beneath the platform plate (551). The movable vacuum box is configured to traverse along the length of the platform plate while covering substantially the entire width thereof when actuated. This arrangement enables selective and localized application of vacuum pressure across different sections of the platform plate, thereby providing additional flexibility in substrate handling and improving control over suction-assisted lifting operations.

[0166] Figure 21 illustrates a perspective view of a film application station (350) according to. The film application station comprises a film roll (351) configured to store a polymer film prior to application. A roller (353) is operatively arranged to rotate and unwind the film from the roll, the roller being actuated by a servo motor (352) to dispense the film to a predetermined and precise length. Mounting brackets (354) are provided to secure the activity station (350) onto the conveyor frame, thereby enabling modular integration within the coating line.

[0167] In operation, the servo motor (352) drives-controlled unwinding of the film roll (351) under feedback from the central controller, ensuring that the film is dispensed in synchronization with substrate positioning at the downstream activity station. The roller (353) maintains tension across the film during unwinding to prevent slack or misalignment. In certain embodiments, additional tensioning rollers, guide rails, or alignment sensors may be provided to enhance precision and stability of film placement.

[0168] Figure 22 illustrates a perspective view of an excess film cutting station (650) according to an embodiment. The station comprises a cutting plate (651) configured to engage a coating cavity plate positioned on the conveyor. A plurality of round cutting dies (652) are mounted on the cutting plate, each die being dimensioned to align with a corresponding cavity to trim excess polymer film surrounding coated substrates. A pair of pneumatic actuators (654) are operatively connected to the cutting plate (651) and configured to drive the cutting dies (652) downward into the cavities during operation.

[0169] A vibratory motor (655) is coupled to the cutting plate to impart gentle vibration when the cutting dies (652) are engaged, thereby facilitating clean separation of excess film material and reducing sticking or tearing. A support frame (656) secures the cutting station (650) onto the conveyor frame, enabling modular installation, removal, or repositioning.

[0170] In operation, when the conveyor indexes a cavity plate into position, the pneumatic actuators (654) lower the cutting plate (651) such that the round cutting dies (652) enter the cavities and shear excess film material from the periphery of the coated substrates. The vibratory action assists in dislodging trimmed fragments, which may then be collected by a downstream removal system, such as a vacuum suction unit, air-blowing manifold, or mechanical scraper.

[0171] In some embodiments, the cutting dies (652) may be provided with heated edges, enabling thermoplastic films to be simultaneously cut and sealed around the substrate periphery to prevent fraying. In another variation, ultrasonic cutters may be employed in place of mechanical dies, providing rapid, low-force trimming with reduced wear on tooling.

[0172] The actuators (654) may be replaced by servo-driven linear actuators or cam-driven mechanical systems to provide programmable or synchronized motion. In some cases, the cutting plate (651) may incorporate interchangeable die assemblies, allowing adaptation to substrates of different shapes, sizes, or geometries without requiring replacement of the entire station.

[0173] In certain embodiments, the cutting station (650) may also include an integrated wastecollection module, comprising a suction manifold, conveyor, or receptacle to gather trimmed film fragments and maintain a clean operating environment.

[0174] Through these variations, the excess film cutting station provides precise, repeatable, and modular trimming functionality, adaptable to a wide range of coating processes and polymer films.

[0175] Figure 23 illustrates a cross-sectional view, according to at least one embodiment described herein, of a standalone scale coating apparatus 1000, which may be configured for producing small batch quantities of polymer-coated substrates, according to at least one embodiment described herein. The apparatus 1000 comprises a heating device 1001 configured to heat-soften a polymer film 1004. The heating device 1001 is mounted on arms 1002, 1002a, which are operatively coupled to a linear guide rail system 1005. The guide railsystem 1005, positioned on a frame structure 1014, enables the arms 1002, 1002a to travel horizontally over a predetermined distance.

[0176] Referring to Figure 23, a removable cavity plate 1007 is positioned beneath the heating device, the cavity plate comprising a plurality of cavities adapted to receive and hold solid substrates during coating. The cavity plate 1007 is supported by a rectangular frame 1008 that is secured to side members 1014, 1014a of the main frame. A film clamping system 1006 is further provided for securing the polymer film 1004 in position when heat is applied.

[0177] Beneath the cavity plate 1007, a vacuum box 1009 is arranged to apply suction through a plurality of vacuum ports 1016 defined in a vacuum plate 1013 affixed to the top of the vacuum box. A plurality of lifting platforms 1012 are mounted on the vacuum plate 1013 and are configured to raise the substrates from the cavities to facilitate film wrapping during the vacuum-forming step. The vacuum box 1009 is vertically actuated by pneumatic cylinders 1010, 1010a, which are connected via arms 1011 , 1011a to provide controlled upward and downward motion.

[0178] (optional) The system may further comprise a film-unwinding station 1003 configured to dispense the polymer film 1004, which is positioned manually over the substrates prior to heat application. In this configuration, the standalone coating apparatus 1000 operates as a compact system for batch-scale coating of solid substrates with polymer films.

[0179] The present disclosure, according to certain embodiments, provides a modular horizontal conveyor-based apparatus and method for producing polymer-coated solid substrates, including but not limited to fertilizer tablets, granules, or other shaped articles.

[0180] Substrate Holders: The substrates are positioned within substrate holders that are advanced along a conveyor system. The substrate holders may comprise, without limitation, coating cavity plates having a plurality of cavities dimensioned to receive substrates, trays or pallets configured to support substrates in bulk, clamps or grippers configured to hold individual substrates, rotary cups or molds, or recessed conveyor belts incorporating integral cavities. The choice of substrate holder may vary depending on substrate size, geometry, and coating requirements. In some embodiments, the substrate holder may be implemented as a cavity roller, wherein a plurality of cavities are machined or otherwise formed into the outer surface of the roller. Such a configuration corresponds to the cavity roller system previously disclosed by the inventor and enables substrates to be securely retained within the cavities during intermittent advancement of the roller for sequential coating operations.

[0181] Conveyor System: In one embodiment, the conveyor system comprises a pair of parallel conveyor frames arranged to support endless conveyor belts, with transfer units positioned at opposite ends. Substrate holders are advanced along the first conveyor frame, processed under a plurality of activity stations, transferred through the transfer unit to the parallel conveyor frame for further processing, and then returned to the first conveyor frame, thereby enabling continuous cyclic operation. Multiple conveyor modules may be connected in series to achieve scalability and customization of the coating process.

[0182] Activity Stations: A series of activity stations are mounted on one or both conveyor frames and are configured to perform programmed operations on the substrates positioned within the substrate holders. Exemplary activity stations include, without limitation:• Feeding Station: for introducing fertilizer substrates into the substrate holders.• Film Application Station: comprising a film roll and servo-driven roller configured to unwind and position a polymer film over the substrates.• Coating Station: comprising a heating unit to heat-soften the film and a vacuum suction plate system to form the film around the substrates.• Excess Film Cutting Station: comprising cutting dies actuated by pneumatic or servodriven actuators to sever excess film.• Excess Film Collection Station: comprising a suction manifold, vibratory motor, or mechanical scraper to remove trimmed film fragments.• Flipping Station: configured to invert partially coated substrates to expose uncoated surfaces.• Second Film Application and Coating Stations: configured to apply and form an additional polymer film layer, thereby producing fully coated substrates.• Perforation Station: configured to introduce controlled openings into the polymer coating.Wax Overcoating Station: configured to apply one or more wax layers over the polymer coating.Printing Station: configured to imprint letters, numbers, or images onto the polymer- coated substrates.• Collection Station: configured to discharge finished coated substrates into collection bins.

[0183] Modularity and Configurability: The activity stations may be arranged in any required sequence along the conveyor frames. Multiple modules may be arranged in series, each including identical or different sets of stations, thereby enabling scalable, customizable, and reconfigurable coating operations. In another embodiment, a cavity plate buffering station is provided between two conveyor modules. The buffering station is configured to temporarily stack and hold a plurality of cavity plates before sequentially feeding them into the connected modular conveyor frame. This arrangement enables continuous operation of the downstream conveyor system while accommodating variations in upstream or downstream processing speeds, thereby enhancing overall system efficiency and throughput.

[0184] Referring to the Figure 2, in accordance with at least one embodiment described herein, relates to a method of producing polymer-coated solid substrates using a modular horizontal conveyor system (2000). A plurality of coating cavity plates are advanced in a horizontal orientation along a conveyor frame beneath a plurality of activity stations (2003) mounted on the structure (2001). As the cavity plates progress, programmed activities are performed on the solid substrates housed within the cavities. Upon completion of processing within a given module, the coated substrates are collected, while the now-empty coating cavity plates continue to a cavity plate transfer station (2007). The transfer station (2007) is configured to direct the cavity plates onto an opposite, parallel conveyor frame system (2002), where they undergo an additional sequence of activity stations (2008). At the end of the parallel conveyor (2002), the cavity plates are transferred back to the first conveyor system (2001) to repeat the process in a continuous and cyclic manner.

[0185] According to at least one embodiment described herein, a coating module comprises a plurality of activity stations programmed to perform operations on solid substrates in order to produce polymer-coated substrates having desired properties. Exemplary activity stations may include, without limitation: a feeding station; a film application station; a film coating station comprising heating and vacuum forming units; an excess film cutting station; an excess film collection station; a flipping station for partially coated substrates; a coated substrate collection station; a liquid polymer coating station comprising application and drying units; a perforationstation for forming openings in the coating; a wax overcoating station; and a printing station for imprinting letters or images onto the coating.

[0186] The activity stations may be mounted on the conveyor frame system and arranged in any sequence required by the process. Multiple modules, each incorporating identical or different sets of activity stations, may be connected in series to produce polymer-coated substrates in a scalable manner. Activity stations may further be grouped and arranged as required to accommodate specific process configurations.

[0187] A method of producing polymer-coated substrates on a horizontal conveyor system comprises the steps of: advancing and intermittently halting coating cavity plates containing solid substrates beneath a series of activity stations along a first conveyor frame; discharging the coated substrates at the end of the first conveyor frame; transferring the emptied coating cavity plate via a plate transfer unit to a second conveyor frame arranged on the opposite side; advancing and intermittently halting the coating cavity plate beneath a series of activity stations on the second conveyor frame; discharging the coated substrates at the end of the second conveyor frame; and returning the emptied coating cavity plate onto the first conveyor frame through the plate transfer unit for continued operation.

[0188] Referring to Figure 1 and Figure 2, according to at least one embodiment described herein, a horizontal modular coating conveyor system capable of applying two polymer film layers on each side of the modular system is provided. The system comprises:

[0189] Conveyor Frame 701 (as shown in Figure 1): The conveyor frame (701) comprises a frame structure supporting a pair of conveyor timing belts provided with cleats, a pair of pulleys mounted on shafts positioned at opposite ends of the frame, and a programmable servo motor operatively connected to the shafts to drive the conveyor belts. The conveyor belts are configured to circulate around the pulleys to advance and halt cavity plates in a controlled manner along the length of the conveyor frame.

[0190] Activity Stations on Conveyor Frame: the coating conveyor frame, according to an embodiment, supports (as shown in Figure 2) a plurality of activity stations (2003) as previously described.

[0191] Cavity Plate Transfer Unit: At the conclusion of a coating cycle, the empty coating cavity plate is engaged and by a cavity plate transfer unit (713 in Figure 1 and 2007 in Figure 2) and transferred to the opposite conveyor frame (702 Figure 1 and 2002 in Figure 2). The cavity plate is positioned onto the conveyor belt of the conveyor frame (702 Figure 1 and 2002 inFigure 2) between successive cleats, thereby enabling continued circulation and reuse within the modular coating system.

[0192] Conveyor Frame (702 Figure 1 and 2002 in Figure 2): The conveyor frame comprises a frame structure supporting a pair of conveyor timing belts (703 and 703a in Figure 3) provided with cleats (704 in Figure 3), a pair of pulleys (705 and 705a in Figure 3)mounted on shafts positioned at opposite ends of the frame, and a programmable servo motor operatively connected to the shafts to drive the conveyor belts. The conveyor belts are configured to circulate around the pulleys to advance and halt cavity plates in a controlled manner along the length of the conveyor frame.

[0193] Optionally, Activity Stations on Conveyor Frame (702 in Figure 1 and 2002 in Figure 21): the conveyor frame supports none or more, or a plurality, of activity stations, including but not limited to: a feeding station configured to introduce solid substrates into the cavities of a coating cavity plate; a first film application station configured to apply a first polymer film onto the coating cavity plate; a first coating station configured to heat and vacuum form the first film around the solid substrates; a first excess film cutting station configured to sever film material not adhering to the substrate surfaces; a first excess film collection station; a flipping station configured to invert the partially coated substrates to expose uncoated surfaces; a second film application station; a second coating station configured to heat and vacuum form a second polymer film onto the flipped partially coated substrates; a second excess film cutting station configured to sever excess film not adhering to the coated substrates; a second excess film collection station; and a coated substrate collection station configured to remove and collect coated substrates from the coating cavity plate.

[0194] In one embodiment, the modular conveyor system comprises the above-described activity stations mounted on a first conveyor module (701 Figure 1 and 2001 in Figure 21), and an identical set of activity stations mounted on a second conveyor module (702 Figure 1 and 2002 in Figure 21), thereby allowing to increase the production throughput from the same unit.

[0195] In another embodiment, the second conveyor module (702 Figure 1 and 2002 in Figure 21) may comprise a different set of activity stations, such as a molten wax overcoating station, a drying or curing station, or a surface treatment station configured to further modify the coated substrates. In a further embodiment, the modular conveyor system may be configured as a hybrid system in which some modules comprise identical activity stations and others comprise different activity stations, thereby permitting both repetition of certain processes and integration of distinct operations within the same conveyor system.

[0196] In at least one embodiment described herein, the conveyor frame (701 in Figure 1 , 2001 in Figure 2) has a length in the range of about 2 to 10 meters and a width in the range of about 1 to 3 meters. The conveyor frame may be constructed from stainless steel 316 square beams having a cross-section of approximately 80 mm x 80 mm and a wall thickness of approximately 8 mm, the frame being capable of supporting heavy operational loads. The cavity plates are designed to sit securely on the conveyor belt and to travel smoothly along the length of the conveyor frame. In certain embodiments, about 30% to 90% of the structure of the cavity plate is cut out to form cavities. The cavities are positioned inward from the plate edges adjacent to the conveyor belt so that sufficient flat surface remains at the edges to provide stable support for the cavity plate on the conveyor belt. In at least one embodiment described herein, a coating cavity plate comprises of at least one cavity.

[0197] In another embodiment, the feeding station comprises a hopper, a valve, and a vibratory feeder. The vibratory feeder is configured to deliver an approximate amount of solid substrate into the hopper. The hopper is configured to deposit the solid substrates into the cavities of the cavity plate when actuated by a controller. The hopper may include a rectangular mouth corresponding in width to the cavity plate, and the valve comprises a gate positioned at the bottom of the hopper, the gate being configured to open and close in response to actuation by the controller to regulate discharge of the substrates.

[0198] In at least one embodiment described herein, the film unwinder station is configured to unwind a predetermined amount of film when actuated by a controller. The unwinder is provided with a servo motor operatively coupled to a film roll, the servo motor being adapted to unwind the film in precise increments as required by the coating process. One or more pick rollers mounted on the conveyor frame are configured to hold the film in position during advancement of the cavity plate. The unwinder is mounted on the frame structure, and the film supplied therefrom is dimensioned to cover the entire width of the cavities of the cavity plate while also extending beyond the cavity area to provide marginal film portions that secure the film in place during heating and forming.

[0199] In at least one embodiment described herein, the coating station comprises a heating unit and a vacuum suction unit. The heating unit may include infrared (IR) heaters or hot air blower heaters, the heating area being dimensioned to cover the full width of the polymer film. The heaters may be provided with insulating baffles around their structure to minimize heat dissipation. The watt density or air temperature may be selected according to the type and thickness of the polymer film, with IR heaters positioned at an approximate distance of twoinches above from the film surface. Depending on polymer film type and the thickness, the heating system may be operated with a power density in the range of about 1 to 10 kWh per square foot. In at least one embodiment described herein heaters are configured to heat the polymer films between 50-200 degrees centigrade. The heater (heating element area) area generally covers an area larger than the cavity widths of a cavity plate to uniformly heat the film for thermoforming.

[0200] The vacuum suction unit (500 in Figure 5) extends beneath the entire cavity area of the cavity plate as well as an adjacent margin to ensure uniformity of film forming. The required suction capacity may be determined by the number of cavities on the cavity plate and the thickness of the polymer film, wherein larger numbers of cavities and thicker films generally require higher suction airflow. By way of example, a PBAT film of approximately 36 microns in thickness covering twelve cavities of 16 mm diameter tablets required a vacuum suction rate of approximately 145-250 CFM to achieve complete wrapping of the heat-softened film around the substrates. Different film will have different vacuum suction requirement and values may be needed to be generated beforehand from the lab scale unit before using in production line.

[0201] In at least one embodiment described herein, a slot coating die of cast film extrusion die station is provided in place of the film heating station. The slot die coating station is configured to dispense a molten polymer in the form of a continuous film directly onto the coating cavity plate containing the substrates. The slot die is further adapted to apply the polymer layer with a predetermined and controllable thickness, thereby achieving uniform coating across all substrates housed within the cavity plate. This embodiment eliminates the need for a separate film unwinding station, as the polymer layer is deposited in situ by extrusion through the slot die. Accordingly, the process reduces material handling steps, improves precision in film thickness control, and enables the use of polymers that may be more readily applied in molten form rather than as pre-formed films. In at least one embodiment described herein, the extrusion die or film outlet is mounted on a movable platform configured to traverse across the surface of a stationary cavity plate. During operation, the platform is advanced relative to the plate so as to deposit and apply the molten polymer film over the exposed surface of the cavity plate and the substrates seated therein, while the cavity plate itself remains in a fixed position. This arrangement enables uniform film application without requiring movement of the cavity plate, thereby simplifying alignment and reducing mechanical complexity. In a further embodiment, the excess film cutting station is provided with shaped cutting dies having diameters slightly smaller than the cavity diameter. The outside edge of the cutting die engages the cavity wall to sever excess film from around the coated substrates.Heated cutting dies have been found to be more effective than unheated dies. The cutting dies may be mounted on a thermal plate configured to heat the dies to a temperature near the melting point of the polymer film. In some embodiments, the dies are enclosed within a high- temperature silicone sheath, leaving only the die tip exposed, thereby preventing adherence of cut film to the die surface. The heating capacity of the thermal plate may be adjustable between approximately 1 and 10 kWh per square foot, depending on the thickness and melting point of the polymer film. In at least one embodiment described herein, a combined hot air knife and vacuum suction station is employed to remove excess film from the substrates. In this arrangement, a stream of heated air is directed from above the coating cavity plate, while vacuum suction is simultaneously applied from beneath the plate. The combined action of the hot air, which softens and lifts the excess film, and the suction force, which draws the film away, serves to sever and remove surplus material from partially or fully coated substrates in a controlled manner.ln one embodiment, exposure of the substrates to a stream of heated air under vacuum suction not only assists in conforming the polymer film to the substrate surface but also severs excess portions of the film that fail to adhere. This operation may thereby eliminate the need for a dedicated cutting station (600). However, in certain configurations, the hot-air station may be employed in combination with a subsequent cutting station to further ensure removal of residual film segments.

[0202] In at least one embodiment described herein, the excess film collection unit comprises a vacuum suction inlet positioned adjacent to the cutting station. The vacuum suction inlet is configured to capture and withdraw severed portions of excess film and to transport the removed material into a designated collection bin. This arrangement provides a simple and efficient means for handling waste film, thereby maintaining cleanliness of the processing area and facilitating disposal or recycling of excess material.

[0203] In at least one embodiment described herein, the flipping station comprises a pair of robotic arms positioned on opposite sides of the conveyor frame. The robotic arms are programmable industrial units capable of performing multiple handling tasks and configured to hold an identical cavity plate in an inverted orientation. When a coating cavity plate containing partially coated substrates arrives at the flipping station, a sensor detects its presence and actuates a pushing plate mechanism. The pushing plate is disposed beneath the conveyor frame and is operatively connected to a pair of pneumatic cylinders configured to raise and lower the plate. Upon actuation, the pushing plate elevates the cavity plate containing partially coated substrates toward the inverted cavity plate held by the robotic arms. Once the cavity plate reaches the designated position, the robotic arms grip the cavity plate and align it beneaththe inverted empty cavity plate. The robotic arms then rotate the two aligned cavity plates together through 180 degrees, thereby transferring the partially coated substrates into the cavities of the lower plate while inverting the substrates to expose their uncoated surfaces. After completion of the rotation, the robotic arms release the lower cavity plate containing the inverted substrates to the pushing plate. The pushing plate then descends and returns the cavity plate to its original position on the conveyor belt for subsequent processing. The pushing plate may be dimensioned with a surface area smaller than the cavity plate, thereby allowing it to fit within the conveyor frame structure and perform lifting and lowering operations without obstruction.

[0204] In at least one embodiment described herein, partially coated substrates may be flipped within the same cavities of the coating cavity plate or inverted and repositioned into different cavities of a cavity plate. In yet another embodiment, the substrates are inverted by an external flipping apparatus, after which the cavity plate containing the inverted substrates is placed onto a different section of the conveyor system for further processing.

[0205] In at least one embodiment described herein, the coated substrates are collected by a vacuum suction system extending across the width of the cavity plate, the system being configured to extract the coated substrates by suction and deposit them into a collection bin. In a further embodiment, the coated substrates may be collected by a robotic arm, wherein the robotic arm is programmed to lift the cavity plate, invert the substrates into a collection bin, and subsequently return the cavity plate to its original position on the conveyor frame for reuse.

[0206] A modular horizontal conveyor coating apparatus comprises: a two or more conveyor frames; a pair of cavity plate transfer units positioned at opposite ends of the frames and configured to transfer cavity plates between the parallel conveyor frames; and a series of activity stations mounted on one or both of the conveyor frames.

[0207] In certain embodiments, the conveyor system may be configured for operation in a horizontal, vertical, or inclined orientation, while maintaining the intermittent indexing and sequential processing of substrates at the activity stations.

[0208] In at least one embodiment described herein, the cavity plates remain stationary in position while the activity stations are mounted on a rail system. The activity stations are configured to advance and halt along the conveyor frame, sequentially performing different coating activities on substrates retained within a cavity plate. Upon completion of all activities, the cavity plate is rotated approximately 180 degrees about its central pivot point to dischargethe coated substrates into a collection bin positioned beneath it. In this embodiment, the movement of the activity stations and the operation of the vacuum suction units are synchronized and controlled by a controller, thereby ensuring smooth and reliable operation.

[0209] In a further embodiment, a plurality of cavity plates may be mounted on a rotary table, with the activity stations moving around the table or, alternatively, the rotary table moving with respect to stationary activity stations.

[0210] Although the present disclosure primarily describes a cavity plate-based conveyor coating system, the principles of the invention may likewise be applied to a cavity roller-based coating apparatus previously developed by the inventor. In such an embodiment, the cavity roller is configured to operate in an intermittent mode, wherein the roller is alternately advanced and halted. A plurality of functional stations, including substrate feeding, film application or coating, and cutting or trimming, may be positioned around the outer circumference of the roller. During operation, the intermittent advancement and halting of the roller allows the substrates seated in the cavities to be sequentially subjected to the coating-related operations at the respective stations.

[0211] All such variations and embodiments are considered within the scope of the present invention, and a person skilled in the art will recognize additional modifications and equivalent configurations based on the teachings provided herein.

[0212] In another embodiment, an apparatus for intermittent coating utilizing a vertical conveyor system is described. The apparatus comprises a plurality of coating cavity plates affixed to a chain conveyor arranged in an endless loop about two sprockets. A series of activity stations are mounted along the upper run of the vertical conveyor, the activity stations including, without limitation, a feeding station, a first film application station, a first coating station, a first excess film cutting station, a first excess film collection station, a flipping station, a second film application station, a second excess film cutting station, and a second excess film collection station. The conveyor is operable in an intermittent manner such that the cavity plates are advanced and halted sequentially at each activity station to enable completion of a programmed operation. Upon completion of the coating sequence, the coated substrates are discharged into a collection bin, and the cavity plates are redirected beneath the conveyor to complete the loop and return to the beginning of the series of activity stations.Embodiment-1 : Detailed Description of a Single-Layer Tail-Forming Coating Module

[0213] According to at least one embodiment described herein, a modular film-coating apparatus comprises a sequence of activity stations arranged along one or more conveyor frames to apply a single polymer film layer onto solid substrates retained in coating cavity plates. The sequence may include a feeding station for loading substrates into cavities, a film application station for overlaying a polymer film, a coating station comprising a heating device and vacuum forming unit to wrap the film around the substrates and generate excess film tails, a cutting station to remove excess film while leaving a tubular tail projection, a collection station for severed film fragments, and a tail melt-fusing station to collapse and integrate the tail into the coating. Optional modules may include an overcoating station for applying a molten or liquid polymer layer to cover imperfections and a drying or curing station to solidify the applied coating. Finally, a collection station receives the fully coated substrates. The modular configuration allows incorporation or omission of optional stations, thereby enabling adaptation to different substrates, coating materials, and functional requirements.Embodiment-2: Detailed Description of a Modular Liquid Coating Module

[0214] According to at least one embodiment described herein, a method of applying a liquid polymeric coating onto solid substrates positioned within cavities of a cavity plate is provided. The method comprises positioning a plurality of substrates within the cavities, elevating the substrates relative to the plane of the cavity plate, and bringing the exposed surfaces into controlled contact with a polymer reservoir. The reservoir may comprise a foam pad, porous carrier, fibrous applicator, or other absorbent medium impregnated with a liquid polymer composition. Upon momentary contact, a layer of liquid coating is transferred to the substrate surfaces, after which the substrates are lowered back into their cavities and the coating is dried or cured to yield a polymer film.

[0215] In one embodiment, the coating process is implemented within a modular liquid coating system, wherein one or more coating modules are positioned along a conveyor. Each module comprises a sequence of activity stations, including a feeding station for loading substrates, a liquid coating application station for transferring polymer onto elevated substrates, an optional scraper to disengage substrates adhering to the applicator, and a drying or curing station employing heating, vacuum, infrared, ultraviolet, or forced airflow. Multiple coating modules may be arranged in series to apply successive layers or distinct coating types.

[0216] The liquid polymer composition may include biodegradable polymers such as poly(butylene adipate-co-terephthalate) (PBAT), polycaprolactone (PCL), polylactic acid (PLA), polyhydroxyalkanoates (PHB, PHBV), starch derivatives, cellulose ethers, alginates,pectins, proteins (gelatin, zein, casein), or chitosan, as well as non-biodegradable polymers such as polyethylene wax emulsions, polypropylene dispersions, polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyvinyl acetate (P Ac), acrylic emulsions, polyurethane dispersions, epoxy emulsions, or fluoropolymers such as PVDF. The choice of polymer is determined by desired coating thickness, permeability, biodegradability, or release characteristics.

[0217] The polymer composition may exhibit a viscosity of about 1-100,000 mPa s at 25 °C, with lower viscosities suitable for spray coating, intermediate viscosities for dip or brush coating, and higher viscosities for screen printing, extrusion, or pad transfer methods.

[0218] Moisture Barrier Overcoating: In certain embodiments, the coating layer is configured to provide a moisture barrier. Suitable materials include halogenated polymers such as PVDC, acrylic copolymers such as PMMA, hydrophobic polyurethane dispersions, epoxy resins, or waxes and lipid-based coatings including paraffin, carnauba, beeswax, fatty acid esters, and blends thereof. The barrier may be applied as melts, solutions, emulsions, or dispersions and subsequently dried or cured to form a continuous moisture-resistant film.

[0219] A moisture barrier overcoating station may be positioned downstream of a dual film coating station. Multiple such stations may be employed to apply successive barrier layers of the same or different compositions. One or more drying stations may be associated with the barrier station to remove carrier medium. The moisture barrier may be applied in an amount of about 0.1% to 30% by weight of the polymer coating, preferably 0.5-5%. In one embodiment, a reservoir is provided in fluid communication with the application pad to replenish barrier chemicals and maintain consistent transfer.

[0220] Wax Overcoating: In another embodiment, a wax overcoating station is positioned downstream of a film coating station to apply a wax layer onto the polymer-coated substrates. Multiple stations may be used to apply successive wax layers, which may comprise natural waxes (beeswax, carnauba, candelilla, soy wax) or non-biodegradable waxes (paraffin, microcrystalline, Fischer-Tropsch, polyethylene). One or more drying stations may be associated with each wax application step.

[0221] Wax may be applied using a foam roller or fibrous pad impregnated with liquid wax or paste, with substrates elevated into contact by a pushing system. A wax reservoir may be provided in fluid communication with the pad to replenish coating levels during operation. The wax is typically applied in an amount of about 0.1% to 5% by weight of the polymer coating.Embodiment-3: Intermittent standalone Coating Process

[0222] According to at least one embodiment described herein (Figure 26), a coating apparatus is provided which is configured as a stand-alone intermittent system for producing limited quantities of polymer-coated substrates. The apparatus is particularly suited for laboratory-scale operations, pilot-scale testing, and specialized production scenarios in which smaller volumes are required rather than continuous high-throughput processing.

[0223] Heating System: The apparatus comprises a heating device configured to heat-soften a polymer film prior to forming it around solid substrates. The heating device is mounted on supporting arms operatively connected to a linear guide rail system secured to a rigid frame. The guide rail permits controlled horizontal displacement of the heating device, enabling precise positioning relative to the film and substrates to ensure uniform heating across the film surface.

[0224] Substrate Holding System: Positioned beneath the heating device is a removable cavity plate comprising a plurality of cavities dimensioned to receive and securely hold solid substrates. The cavity plate is manually insertable and removable, allowing flexible loading and unloading of substrates, retrieval of coated products, or substitution with plates adapted for different geometries and sizes. The plate is retained within a rectangular frame fastened to opposing side members of the apparatus, thereby maintaining positional stability during operation.

[0225] Film Clamping System: A film clamping mechanism is disposed above the cavity plate to secure the polymer film during heating and forming. The system prevents lateral or longitudinal displacement of the film, ensuring that once softened, the film conforms uniformly to the contours of the substrates and cavity plate.

[0226] Vacuum Forming System: Beneath the cavity plate is a vacuum box supporting an upper vacuum plate provided with a plurality of vacuum ports in fluid communication with the vacuum box interior. When suction is applied, the softened film is drawn downward into intimate contact with the substrates. A plurality of lifting platforms are mounted on the vacuum plate, each aligned with a cavity of the cavity plate. During suction, the lifting platforms raise the substrates slightly to facilitate conformal wrapping of the film and promote uniform coating thickness.

[0227] Vertical Actuation System: The vacuum box is vertically displaceable by pneumatic cylinders operatively connected through support arms. The cylinders enable precise upwardand downward displacement of the vacuum box, permitting engagement with the cavity plate during forming and disengagement during non-forming stages.

[0228] Film Supply System: A film-unwinding station is provided to supply the polymer film. The unwinder supports a roll of film which can be manually advanced and cut to size before positioning over the cavity plate. The arrangement allows rapid replenishment or replacement of rolls, accommodating films of varying composition, thickness, or barrier properties as required by the intended application.

[0229] Operation: In use, substrates are placed into the cavities of the cavity plate, which is positioned on the frame above the vacuum plate. A length of polymer film is unwound and clamped in place. The heating device is positioned and activated to soften the film. The pneumatic cylinders then raise the vacuum box into engagement with the cavity plate while suction is applied, drawing the softened film downward around the substrates. Simultaneously, the lifting platforms elevate the substrates slightly to ensure complete conformity of the film around their surfaces.

[0230] After forming, excess film may be trimmed. The partially coated substrates can be removed, flipped manually or by an auxiliary device, and reintroduced for a second cycle to achieve full coating coverage.

[0231] Advantages: This intermittent coating apparatus (1000) enables controlled small-batch production of polymer-coated substrates. The removable cavity plate design allows rapid changeover between production runs, while the heating, clamping, and vacuum systems provide reproducible and consistent coating quality. Its compact, stand-alone configuration reduces space and infrastructure requirements, making it particularly suitable for laboratory use, pilot-scale trials, and specialized production environments where continuous conveyor systems are impractical.Embodiment-4: Polymer Coated Fertilizers substrates with Micro-Perforation

[0232] In coated fertilizer tablets, particularly those of larger size, the nutrient core typically contains a high concentration of salts such as, nitrates, or phosphates. When moisture diffuses through the polymer coating, these salts readily dissolve and create a highly concentrated internal solution. The larger the tablet, the greater the volume of dissolved salts that accumulates, resulting in very high osmotic pressure inside the core. This osmotic imbalance exerts mechanical stress on the coating and often prolongs the lag phase, because the coating must first absorb significant amounts of water and expand before any release can occur. Oncethe osmotic pressure exceeds the coating’s resistance, a sudden rupture or uncontrolled release of nutrients often follows. This problem is pronounced in larger size substrates, where the osmotic gradient is stronger and the risk of coating failure is higher, leading to erratic nutrient delivery.

[0233] The introduction of engineered perforations addresses this challenge by providing defined exit pathways that relieve osmotic build-up. Instead of waiting for water to diffuse uniformly through the coating and for pressure to accumulate, moisture enters through the perforations and dissolves the nutrient salts, while the dissolved solution is able to diffuse out at a controlled rate. This prevents excessive internal osmotic pressure from forming, thereby reducing the lag phase, avoiding sudden bursts of nutrient release, and ensuring a more stable, continuous diffusion process. In effect, the perforations allow large, high-salt tablets to function as reliable controlled-release systems, even when the osmotic forces would otherwise compromise coating integrity and release uniformity.

[0234] In one embodiment, a polymer-coated substrate is provided and advanced on a conveyor system through a feeder into a holding cavity configured to retain a single coated substrate. The substrate is then advanced to a perforation station comprising a perforation unit with a sharp tip or perforation edge, or a laser perforation apparatus. When the coated substrate passes under the perforation unit, the tip contacts the polymer coating and forms a defined perforation. The perforated substrate may thereafter be transferred to a coating station where an additional polymer layer or soluble material is applied to cover or regulate the perforation, followed by passage through a heating station to dry and fix the applied layer.

[0235] In another embodiment, the perforation station may be equipped with a heating mechanism. The tip of the perforation element is heated to a temperature suitable for softening or melting the polymer coating at the point of contact. The heated tip thereby forms a perforation in the polymer coating of the substrate.

[0236] The polymer-coated substrate may be in the form of a granule, tablet, briquette, or pillow pouch. The substrate may range from 1 mm granules to 100 mm briquettes, preferably 3 mm to 40 mm in diameter. The polymer coating thickness may range from about 10 micrometres to 5 millimetres, preferably between 15 micrometres to 300 micrometres, more preferably between 25 micrometeors to 150 micrometres. In at least one embodiment described herein, a polymer-coated fertilizer tablet substrate comprising a first polymer film having a WVTR values between 1-1000 g / m2is provided. Day, applied over the substrate core, a second coating layer disposed over the first polymer film, and a sealing layer positioned overat least a portion of the second coating layer. The coating system further comprises one or more perforations, which may be formed in the first polymer film, the second coating layer, or in both layers, thereby providing defined pathways for controlled fluid ingress and nutrient release.

[0237] The polymeric coating is engineered to include one or more perforations that extend through the thickness of the coating. The perforations establish discrete fluid pathways through the coating and thereby modulate the rate of interaction between the environment and the solid core substrate. The perforations are defined by an equivalent circular diameter in a range of about 5 micrometers to about 500 micrometers. The number and distribution of perforations may be varied. One or more perforation may be performed into the coating of the substrate. .

[0238] The geometry of the perforations may further contribute to performance. In one embodiment, the perforations are substantially cylindrical through-holes. In another embodiment, the perforations are conical or biconical, such that the opening area at the exterior surface differs from the opening area at the substrate-facing surface. Such conical perforations can reduce clogging by soil particles and may influence directional flow of moisture and dissolved constituents.

[0239] In one embodiment, a perforated polymer-coated substrate comprises a solid fertilizer core encapsulated by a polymer coating and at least one perforation through the coating. The perforation creates an opening through which nutrients can diffuse when the substrate is exposed to moisture in soil or growing media. The diameter of the perforation may range from less than 50 micrometre to 250 micrometre. Multiple perforations may be provided depending on the required release profile. Larger diameters or greater numbers of perforations generally increase the release rate.

[0240] In another embodiment, the perforated substrate is further provided with an overcoating polymer layer that covers the perforation. Moisture penetrates the covering layer and moves through the perforation to dissolve the fertilizer core, after which the dissolved material diffuses out through the covering layer. The release rate may be controlled by varying the size of the perforation or by modifying the moisture vapor transmission rate of the covering polymer.

[0241] In yet another embodiment, the polymer coating includes one or more thinned regions of reduced thickness. The thinned regions provide increased moisture vapor transmission relative to the remainder of the coating, thereby functioning as defined release areas. Thinningmay be achieved by pressing a heated or unheated element with a protruding edge against the polymer coating to locally reduce thickness without fully perforating the coating.

[0242] In a further embodiment, the perforation may be filled with a biodegradable or water- soluble plug. The plug material dissolves or degrades upon contact with moisture or soil, thereby opening the perforation after a controlled time delay. By selecting materials of different solubility or biodegradation rates, the onset and duration of nutrient release can be tailored.

[0243] Many methods of micro-perforation may be employed to create a single or multiple perforation into the coating of a polymer coated substrates. The method may be selected depending on the nature of the polymer coating and requirement of the perforation size and these methods may be selected from; a micro-needle perforation, a needle perforation, a laser perforation,

[0244] Various methods may be employed to generate perforations within the defined size range. In one embodiment, perforations are formed by ultrafast laser drilling, such as femtosecond or picosecond pulsed lasers operating at ultraviolet or visible wavelengths, which can create clean holes with diameters as small as about 5 micrometers. In another embodiment, perforations are formed by ultraviolet excimer laser ablation or solid-state laser ablation. In yet another embodiment, perforations are formed using micro-imprinting techniques, wherein a micro-structured mold or shim defines recesses in the coating film, followed by plasma etching or solvent exposure to open through-holes at the recessed regions. Mechanical methods may also be employed, such as arrays of micro-pins or needles capable of puncturing the coating to generate perforations in the tens to hundreds of micrometer range. Chemical or thermal methods, such as the incorporation of removable porogens that dissolve to leave behind voids, may also be used.

[0245] The perforations may be formed either before or after application of the coating to the substrate. Both approaches are contemplated and may be combined in modular manufacturing systems.

[0246] In operation, the presence of perforations within the claimed size range provides a mechanism to control the release profile of the coated substrate. For fertilizer compositions, the perforations permit initial moisture ingress and nutrient egress, thereby achieving a more uniform release curve. The size, density, and distribution of perforations may be selected according to crop type, soil condition, environmental humidity, and desired nutrient delivery schedule. For example, fine micro-perforations of about 5-20 micrometeors may be used tosustain long-term release, while larger perforations of 100-200 micrometeors may be used for short term release. The perforated polymer coated substrates may be blended with nonperforated polymer coated substrates to create a desired release pattern.

[0247] In at least one embodiment described herein, perforated films of greater thickness exhibited a release profile distinct from that of thinner films of the same material and provided with perforations of similar dimensions. Without wishing to be bound by theory, it is believed that the act of puncturing the polymeric film during perforation causes stretching of the material surrounding the puncture site, thereby producing a conical-shaped opening. Thicker films generally form perforations having a longer conical geometry compared to thinner films, which may contribute to differences in release behaviour. Furthermore, polymer films possessing lower elongation at break values tend to produce perforations of cleaner geometry, whereas films with higher elongation values may form irregular or stretched perforations.

[0248] In at least one embodiment described herein, it was observed that polymer films characterized by a higher water vapor transmission rate (WVTR) and provided with a micro perforation exhibited a markedly different release profile compared to polymer films having a lower WVTR with the same type of micro perforation. Specifically, the films with higher WVTR demonstrated a significantly reduced lag time prior to onset of release, whereas the films with lower WVTR exhibited a longer lag period. Accordingly, the WVTR property of the coating film can serve as a critical design parameter in engineering coated products incorporating micro perforations, enabling controlled modulation of nutrient or substrate release characteristics.Exemplary Coated tablets, produced in accordance with the present disclosure, may be provided in perforated or non-perforated forms

[0249] Example 1: A convex-shaped fertilizer tablet having an NPK composition of 21-7-14 was prepared using a Yara Mila turf royale® granular fertilizer product. The tablets were produced with a diameter of approximately 11 mm, a thickness of approximately 8 mm, and an average weight of about 0.9 grams. The tablets were subsequently coated with a linear low- density polyethylene (LLDPE) film, the coating being applied with a thickness of approximately 25 microns on one side and approximately 50 microns on the opposite side, wherein commercially available LLDPE stretch wrap film was utilized. Following coating, a perforation was manually introduced into the 25-micron coating layer using a steel needle, thereby forming openings of approximately 100-130 microns in diameter on the thinner side of the coating. Ten tablets of each type (perforated and non-perforated) were immersed in 300 mL of deionized water, and the water was periodically analyzed using a standard electrical conductivity meterto monitor changes in conductivity, the values being compared with a calibration curve prepared from standard solutions of the same NPK composition. It was observed that the perforated tablets released approximately 10% by weight of the fertilizer content within the first 10 days of immersion, whereas the non-perforated coated tablets released less than 0.5% for the same period.

[0250] Example 2: A calcium nitrate tablet coated with a poly(butylene adipate-co- terephthalate) (PBAT) film was prepared. Convex-shaped tablets having a diameter of approximately 11 mm and a thickness of approximately 8 mm were produced by compressing calcium nitrate powder admixed with 5% w / w magnesium stearate using a laboratory-scale tablet press. The tablets were subsequently coated on a laboratory coating apparatus with a PBAT film having a thickness of about 50 microns, wherein the PBAT was of a home- compostable grade (KIGFA). Two types of coated tablets were prepared and tested. In the first type, the coated tablets were perforated using a steel sewing needle to form perforations of approximately 100 microns in outer diameter, the perforations being of conical geometry due to stretching of the coating from the backside. In the second type, the tablets were left unperforated. Five tablets of each type were immersed in 300 mL of deionized water, and the water samples were periodically analyzed for calcium nitrate release. The perforated tablets exhibited minimal lag phase and initiated release within approximately 2 days of immersion, whereas the non-perforated tablets displayed a lag phase of about 10 days before release commenced.

[0251] Example 3: A compound NPK fertilizer was formulated by blending powdered urea (32% w / w), monoammonium phosphate (MAP, 32% w / w), and sulphate of potash (32% w / w), supplemented with 1% micronutrients and 1% dry biostimulants comprising fulvic acid and potassium humate, 1% dry citric acid. The mixture was compressed into convex-shaped tablets of 8 mm diameter and 6 mm thickness using a laboratory-scale single punch tablet press. Each tablet was subsequently coated with a 50 pm PBAT film. A batch of 10 coated tablets was immersed in deionized water and subjected to release analysis. The results indicated a controlled release profile, with approximately 80% of the incorporated ingredients released into the water over a period of 45 days.

[0252] In certain embodiments, the coating layer is formed from a biodegradable polymer or a blend of biodegradable polymers. The biodegradable polymer maybe selected from the group consisting of: aliphatic polyesters, including but not limited to polylactic acid (PLA), polyglycolic acid (PGA), poly(lactic-co-glycolic acid) (PLGA), polycaprolactone (PCL), poly(butylenesuccinate) (PBS), poly(butylene succinate-co-adipate) (PBSA), poly(butylene succinate-co- terephthalate) (PBST), poly(butylene adipate-co-terephthalate) (PBAT), polyethylene succinate) (PESu), polypropylene succinate) (PPSu), poly(butylene carbonate) (PBC), poly(trimethylene carbonate) (PTMC), polyethylene carbonate) (PEC), and copolymers thereof; polyhydroxyalkanoates (PHAs), including poly(3-hydroxybutyrate) (PHB), poly(3- hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(3-hydroxyhexanoate) (PHHx), poly(3- hydroxyoctanoate) (PHO), poly(3-hydroxydodecanoate) (PHD), poly(4-hydroxybutyrate) (P4HB), and copolymers or blends thereof; starch-based polymers, including thermoplastic starch (TPS) and starch blended with polyesters such as PBAT or PCL; cellulose-based polymers, including regenerated cellulose, cellulose acetate, cellulose acetate butyrate, carboxymethyl cellulose, hydroxypropyl cellulose, and ethyl cellulose; protein-based biopolymers, including zein, soy protein isolate, wheat gluten, gelatin, and collagen; polysaccharide-based biopolymers, including chitosan, alginate, pectin, pullulan, xanthan gum, gellan gum, and hyaluronic acid; and other biodegradable polymers, including polyethylene oxide), degradable polyethylene glycol (PEG) derivatives, polyvinyl alcohol (PVA), polyethylene furanoate) (PEF), poly(butylene furanoate) (PBF), degradable polyurethane, silk fibroin. In some embodiments, the coating films may comprise water-soluble polymers that dissolve under controlled aqueous conditions to facilitate nutrient release. Suitable examples include polyvinyl alcohol (PVA), available in both cold-water soluble and hot-water soluble grades

[0253] In at least one embodiment described herein, the coating films may be formed from non-biodegradable polymers selected for their durability, barrier properties, and controlled permeability. Suitable non-biodegradable polymers include, without limitation, polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polyethylene terephthalate (PET), polycarbonate (PC), polystyrene (PS), acrylonitrile- butadiene-styrene (ABS), ethylene-vinyl acetate (EVA), ethylene-vinyl alcohol (EVOH), nylon (polyamide), and fluoropolymers such as polytetrafluoroethylene (PTFE) and polyvinyl fluoride (PVF). These polymers may be employed individually or as multilayer composites to provide enhanced moisture resistance, mechanical strength, or selective diffusion characteristics. In some embodiments, non-biodegradable films are used where long-term stability, protection from environmental degradation, or sustained release over extended periods is desired.

[0254] In further embodiments, the coating layer comprises blends of the foregoing polymers with one another, or with natural fibres (such as cellulose, hemp, or jute), inorganic fillers (suchas calcium carbonate, talc, or clay), or biobased plasticizers (such as glycerol, sorbitol, or citrate esters).

[0255] In at least one embodiment described herein, the coating film may comprise a blend of biodegradable and non-biodegradable polymers, thereby combining the environmental advantages of degradable materials with the durability and barrier properties of conventional polymers.

[0256] The polymer film, as described herein, may be selected to exhibit a water vapor transmission rate in the range of about 1 g / m2day to about 2000 g / m2day, measured under standard ASTM F1249 testing conditions. Such films may be engineered to provide tailored release profiles for coated substrates by controlling moisture ingress through the coating. In certain embodiments, the film may exhibit a WVTR of less than 10 g / m2day to function as a strong moisture barrier, while in other embodiments, the film may exhibit a WVTR of greater than 100 g / m2day to facilitate accelerated moisture transfer and release. The coating with a large size or multiple perforation may have a higher water vapor transmission rate.

[0257] As used herein, the term “polymer film” refers to a continuous layer of polymeric material exhibiting an elongation at break of about 5% to about 1000%, as measured according to ASTM D882. In certain embodiments, the polymer film may be characterized by low elongation values (5-50%), indicative of brittle or semi-crystalline polymers, while in other embodiments the polymer film may be characterized by high elongation values (greater than 300%), typical of ductile or elastomeric polymers. The selection of elongation range may be tailored to achieve desired properties such as flexibility, crack resistance, or controlled fracture under stress.

[0258] In certain embodiments, one or more hydrolysis stabilizers are incorporated into the biodegradable polymer film in order to reduce the rate of polymer chain hydrolysis when the coated fertilizer is exposed to soil. The stabilizers may be present in an amount ranging from about 0.01% to about 5% by weight of the polymer.

[0259] In at least one embodiment described herein, the biodegradable polymer composition may further comprise one or more hydrolysis stabilizers selected from carbodiimides, epoxyfunctional stabilizers, oxazoline-functional stabilizers, isocyanate-functional stabilizers, acid scavengers, moisture scavengers, antioxidant stabilizers, and light stabilizers. Exemplary carbodiimides include monomeric carbodiimides, polymeric carbodiimides, and multifunctional carbodiimide oligomers. Exemplary epoxy-functional stabilizers include multifunctional epoxyoligomers, glycidyl methacrylate copolymers, and epoxy-functional styrene-acrylic oligomers. Exemplary oxazoline-functional stabilizers include polyfunctional oxazoline oligomers and oxazoline-containing copolymers. Exemplary isocyanate-functional stabilizers include aliphatic or aromatic polyisocyanates and blocked isocyanates capable of regenerating reactive -NCO groups. Acid scavengers may be selected from layered double hydroxides such as hydrotalcite, metal oxides such as magnesium oxide and calcium oxide, metal hydroxides such as magnesium hydroxide, aluminum hydroxide, or calcium hydroxide, metal carbonates such as calcium carbonate, and metal stearates such as calcium stearate or zinc stearate. Moisture scavengers may include calcium oxide concentrates, molecular sieves, or anhydrous salts. Antioxidant stabilizers may include hindered phenolic antioxidants, phosphite antioxidants, thioether antioxidants, or mixtures thereof, while ultraviolet light stabilizers may include hindered amine light stabilizers, benzotriazole UV absorbers, benzophenone UV absorbers, and triazine UV absorbers. The hydrolysis stabilizer may be present in an amount from about 0.05% to about 5% by weight of the total composition and may function by reacting with or neutralizing carboxyl or hydroxyl end groups, by binding or consuming water molecules, by neutralizing acidic degradation products, or by preventing oxidation that generates hydrolytic catalysts.

[0260] In certain embodiments, the solid substrate comprises a fertilizer selected from nitrogen fertilizers including urea, ammonium nitrate, calcium ammonium nitrate, ammonium sulfate, ammonium phosphate nitrate, ammonium chloride, calcium cyanamide, and urea-ammonium nitrate solutions; phosphate fertilizers including monoammonium phosphate, diammonium phosphate, triple superphosphate, single superphosphate, monopotassium phosphate, phosphoric acid salts, and rock phosphate; potassium fertilizers including potassium chloride, potassium sulfate, potassium nitrate, potassium magnesium sulfate, potassium carbonate, and potassium phosphates; calcium, magnesium, and sulfur fertilizers including calcium nitrate, calcium ammonium nitrate, calcium phosphate, calcium sulfate (gypsum), magnesium sulfate, magnesium nitrate, kieserite, dolomite, elemental sulfur, and ammonium thiosulfate; micronutrient fertilizers including iron salts and chelates, zinc salts and chelates, manganese salts and chelates, copper salts and chelates, boron sources including borax and boric acid, molybdenum sources including sodium molybdate and ammonium molybdate, and cobalt salts; compound or mixed NPK fertilizers of various formulations including but not limited to 10-10-10, 15-15-15, 20-20-20, and 10-52-10, as well as slow-release or stabilized fertilizers including sulfur-coated urea, polymer-coated urea, urease-inhibited urea, and nitrification- inhibited urea; water-soluble NPK blends; liquid fertilizers solidified or adsorbed onto a carrier; and organic or naturally-derived fertilizers including bone meal, blood meal, feather meal, fishmeal, fish emulsion, guano, seaweed or kelp extracts, compost-derived fertilizers, and biochar impregnated with nutrients.

[0261] In certain embodiments, the solid substrates have an average diameter ranging from about 1 mm to about 200 mm and a weight ranging from about 10 mg to about 200 g.

[0262] In certain embodiments, the solid substrates may comprise a fertilizer granule, fertilizer tablet, fertilizer briquette, or other shaped fertilizer substrates, sulfur coated fertilizer substrate, polymer coated fertilizer substrate, as well as a water treatment tablet, a biocide pellet, a natural seed, or a toilet bowl cleaning tablet, or the like.

[0263] In certain embodiments, the solid substrate may comprise any solid particulate material or shaped article, including but not limited to granules, pellets, briquettes, tablets, capsules, seeds, or other compacted forms suitable for coating.

[0264] In certain embodiments, the fertilizer substrate or the coating further comprises one or more biostimulants selected from the group consisting of seaweed and algal extracts including Ascophyllum nodosum, Ecklonia maxima, Laminaria species, Sargassum species, Chlorella species, Spirulina species, and hydrolyzed algal polysaccharides such as laminarin, fucoidan, and alginate; humic substances including humic acids, fulvic acids, humates, and leonardite extracts; protein hydrolysates and amino acids including plant-derived protein hydrolysates, animal-derived protein hydrolysates, and free amino acids such as glycine, glutamic acid, proline, and arginine; microbial biostimulants including plant growth-promoting rhizobacteria such as Bacillus, Pseudomonas, Azospirillum, and Azotobacter species, mycorrhizal fungi including arbuscular mycorrhizal fungi, Trichoderma species, and endophytic bacteria or fungi; chitosan and chitosan derivatives including chitosan oligosaccharides and N- acetylglucosamine derivatives; hormone-like compounds including auxin-like compounds such as indole-3-acetic acid and indole-3-butyric acid, cytokinin-like compounds such as kinetin, zeatin, and benzylaminopurine analogs, gibberellin-like compounds, and brassinosteroid analogs; microbial metabolites including exopolysaccharides, siderophores, organic acids such as gluconic acid, citric acid, and lactic acid, and volatile organic compounds; silicon sources including potassium silicate, sodium silicate, and stabilized silicic acid; natural extracts including yeast extracts, aloe vera extracts, green tea polyphenols, and plant-derived oligosaccharides such as p-glucans and arabinogalactans; and secondary metabolites including salicylic acid, jasmonic acid derivatives, and melatonin, or mixtures thereof.

[0265] In certain embodiments, biostimulants are precoated onto the solid substrates prior to the application of a polymer coating. In other embodiments, the biostimulants are applied as an overcoat onto polymer-coated substrates.

[0266] In certain embodiments, a fertilizer composition formed into a solid tablet or briquette shape is provided, wherein the composition comprises one or more natural organic fertilizers as the primary nutrient source. The tablet form offers ease of handling, dust free , controlled release of nutrients, and suitability for application in soil, container media. The organic fertilizers may be selected, without limitation, from animal-derived materials such as bone meal, blood meal, feather meal, fish meal, fish hydrolysate, meat and bone meal, horn meal, hoof meal, poultry litter, and animal manures including cattle manure, poultry manure, and swine manure; plant-derived materials such as soybean meal, cottonseed meal, canola meal, corn gluten meal, alfalfa meal, seaweed meal, kelp extract, molasses, and press mud; microbial and fermentation products such as spent mushroom compost, yeast extract, or microbial biomass; and mineral-derived natural sources such as rock phosphate, guano, greensand, langbeinite, dolomite, limestone, gypsum, wood ash, and natural potassium salts. The organic fertilizer tablet may further comprise optional additives including biochar, humic substances, fulvic acids, amino acids, or biostimulants to enhance soil activity and nutrient uptake.

[0267] In at least one embodiment described herein, a fertilizer composition formed into a solid tablet or briquette, the composition comprising one or more components selected from; a synthetic fertilizers, a natural fertilizers, a micro-nutrients, a tablet processing additives, a biostimulants, and a pesticides, is provided.

[0268] In at least one embodiment described herein, the polymer-coated fertilizer substrate may further comprise one or more additives formulated to co-release with phosphate in order to reduce fixation and improve nutrient availability in soil. When phosphate ions are released from the coated substrate, they typically undergo strong sorption or precipitation reactions with calcium, iron, or aluminum minerals in the soil, thereby limiting their plant availability. To mitigate this, the fertilizer core and / or perforation plug may incorporate biodegradable chelating agents such as citric acid, malic acid, gluconic acid, or readily biodegradable aminocarboxylates such as GLDA, MGDA, or IDS, which form soluble complexes with multivalent cations. In other embodiments, humic or fulvic substances, polyaspartic acid, polyepoxysuccinic acid, or other scale-inhibiting polymers may be included to condition the soil micro-zone surrounding the release point. Silicate donors, such as sodium silicate orpotassium silicate, may also be co-released to compete with phosphate for adsorption sites on iron and aluminum oxides, thereby preserving phosphate mobility. These additives may be blended into the nutrient core, applied as a micro-laminate beneath the coating, or incorporated into fast-dissolving plugs positioned within engineered perforations of the coating. Upon release, the additives create a localized micro-environment that suppresses phosphate fixation, ensuring that the nutrient remains in a plant-available form for extended periods.

[0269] The polymer-coated fertilizer substrate according to at least one embodiment described herein comprises one or more phosphate fixation inhibitors selected from biodegradable organic acids, biodegradable aminocarboxylates, humic or fulvic substances, polyaspartic acid, polyepoxysuccinic acid, silicate donors, or combinations thereof, the inhibitors being formulated to co-release with phosphate from the substrate so as to reduce binding of phosphate to soil minerals and enhance nutrient availability. The phosphate fixation inhibitor is present in an amount of about 0.1% to about 10% by weight of the fertilizer substrate.

[0270] In certain embodiments, the natural organic fertilizers may be combined with one or more chemical or synthetic fertilizers to provide a more complete and balanced plant nutrition profile. The resulting composition may be processed into a solid tablet form, thereby facilitating ease of handling, transportation, and application. The fertilizer tablet may further be coated with at least one layer of a polymeric material, the coating serving to control moisture ingress, reduce odor emission, and regulate the rate of nutrient release into the surrounding environment.

[0271] In at least one embodiment described herein, particulate urea (46-0-0) is blended with particulate methylene urea (38-0-0) at a 1 :1 weight ratio and compacted to form a hybrid fertilizer pellet having a dimension of about 5 mm on the largest side. The pellet is thereafter overcoated with a biodegradable poly(butylene adipate-co-terephthalate) (PBAT) polymer film having a thickness of about 35 pm to yield a polymer-coated hybrid nitrogen pellet.

[0272] In at least one embodiment described herein, particulate urea is blended with one or more urease inhibitors and one or more nitrification inhibitors, compacted to form pellets, and subsequently over-coated with a biodegradable or a non-biodegradable polymer layer to regulate water ingress and nitrogen release. The urease inhibitor may comprise, for example, NBPT or NPPT, and the nitrification inhibitor may comprise, for example, DCD, DMPP, or nitrapyrin. The polymer overcoat is applied at a thickness sufficient to achieve the desired controlled-release profile.

[0273] In at least one embodiment described herein, the fertilizer ingredients employed for hydroponic formulations may be selected from highly water-soluble salts commonly used in fertigation and hydroponics. Suitable macronutrient sources include calcium nitrate, potassium nitrate, magnesium nitrate, ammonium nitrate, ammonium sulfate, monopotassium phosphate, monoammonium phosphate, phosphoric acid, potassium sulfate, potassium bicarbonate, calcium chloride, and magnesium sulfate. Micronutrient sources may include chelated or nonchelated salts such as iron (e.g., Fe-EDDHA, Fe-DTPA, or ferrous sulfate), manganese sulfate or Mn-EDTA, zinc sulfate or Zn-EDTA, copper sulfate or Cu-EDTA, boric acid or sodium borate, and molybdenum salts such as sodium molybdate or ammonium molybdate. These ingredients may be used individually or in combination to prepare balanced nutrient formulations tailored for hydroponic crop production.

[0274] In certain embodiments for soil application, the fertilizer tablet or briquette further comprises a urea-formaldehyde (UF) hardening system — optionally melamine-modified (MUF) or methylene-urea — incorporated as a binder and a slow-release form of nitrogen in an amount of about 0.2% to 80% by weight, preferably about 0.5% to 50% by weight of the composition. The UF resin may be provided as an aqueous prepolymer or powder together with a latent acid catalyst (e.g., ammonium chloride or ammonium sulfate, phosphoric acid, or p-toluenesulfonic acid) and cured prior to or during post-press drying to form a crosslinked, water-insoluble matrix that increases diametral crushing strength, reduces friability and abrasion, and moderates initial wetting and release. Suitable curing conditions include a tablet core pH of about 4.5-6.5 and a temperature of about 50-90 °C for a time sufficient to achieve dimensional stability; in some embodiments ambient curing at controlled humidity may be employed. The hardened core may subsequently be over-coated with one or more polymer films and / or wax layers without compromising structural integrity, provided that curing is substantially complete prior to film application. Without being bound by theory, the crosslinked network reduces open porosity and suppresses rapid water ingress, thereby extending the lag phase and promoting sustained nutrient delivery in soil; additionally, UF contributes slow- release nitrogen as the resin hydrolyzes and biodegrades in situ. Low-emission UF or MUF grades may be selected to minimize free formaldehyde, and highly alkaline fillers that inhibit cure are preferably limited or excluded. This UF-based hardening approach is particularly suited to soil-applied controlled-release fertilizers and is generally not intended for hydroponic use requiring fully water-soluble matrices.

[0275] In certain embodiments for soil application, the fertilizer tablet or briquette further comprises a slow-release nitrogen source selected from isobutylidene diurea (IBDU) andcrotonylidene diurea (CDU). The IBDU and / or CDU may be incorporated as particulate solids (e.g., about 50-500 pm for tablets, optionally pre-granulated to about 0.5-1 .5 mm for briquettes) in an amount of about 5% to 60% by weight of the composition, thereby providing a substantial fraction of the total nitrogen. Without being bound by theory, IBDU and CDU release nitrogen primarily by moisture- driven hydrolysis to urea, with rates that increase with temperature and, in many soils, modest acidity; CDU generally hydrolyzes faster than IBDU under comparable conditions. Inclusion of IBDU / CDU reduces hygroscopicity and can increase tablet hardness due to their crystalline, low-solubility nature; however, a supplemental binder (e.g., starch, PVA, PVP, lignosulfonate, or UF resin) may be employed at about 0.2% to 5% by weight to achieve a target crushing strength without compromising release characteristics. In polymer-coated embodiments, engineered perforations or thinned regions may be provided to admit moisture, and, in alkaline or calcareous soils, a localized acidifying or chelating microadditive (e.g., citrate or ammonium sulfate at about 0.5% to 3% by weight positioned adjacent to a perforation) may be used to promote hydrolysis and stabilize nutrient availability. IBDU / CDU-containing tablets are intended for soil use and are generally not preferred for hydroponic systems requiring fully water-soluble matrices.

[0276] In certain embodiments, the fertilizer tablet may further comprise one or more processing additives selected to aid compaction, improve flow, or modify tablet integrity. Suitable additives include lubricants and glidants such as magnesium stearate, calcium stearate, stearic acid, sodium stearyl fumarate, talc, colloidal silica, or polyethylene glycol; binders and fillers such as starch, pregelatinized starch, microcrystalline cellulose, lactose, sucrose, mannitol, sorbitol, maltodextrin, dicalcium phosphate, or calcium carbonate; disintegrants or porosity enhancers such as crosslinked polyvinylpyrrolidone, croscarmellose sodium, sodium starch glycolate, or cellulose derivatives; anti-caking or flow agents such as kaolin, bentonite, silica-based agents, or magnesium aluminosilicates; and co-processing aids such as waxes, fatty alcohols, or polymer dispersions. Optional colorants or pigments, including iron oxides, titanium dioxide, or food-grade dyes, may also be incorporated.

[0277] In at least one embodiment described herein, one or more processing additives are incorporated into the fertilizer tablet in an amount ranging from about 0.01% to about 20% by weight of the total fertilizer composition. The specific proportion may be selected depending on the nature of the fertilizer salts, the desired tablet hardness, flowability, and compaction characteristics, as well as the release profile of the finished product.

[0278] In at least one embodiment described herein, chlorine tablets formulated for controlled- release applications are provided, wherein the chlorine source may be selected from trichloroisocyanuric acid, sodium dichloroisocyanurate, calcium hypochlorite, chlorinated lime, or mixtures thereof. The chlorine tablets may be coated with one or more polymeric barrier materials to regulate the ingress of water and the rate of chlorine dissolution. The coating may be applied as a continuous film, a multilayer structure, or a micro-perforated layer to balance long-term release with prevention of burst dissolution.

[0279] In at least one embodiment described herein, toilet bowl cleaner tablets configured in solid form and coated to achieve controlled release of active cleaning agents are provided. The toilet bowl cleaner tablets may comprise, without limitation, chlorine-releasing compounds such as trichloroisocyanuric acid, sodium dichloroisocyanurate, calcium hypochlorite, or chlorinated lime; oxygen-releasing compounds such as sodium percarbonate, sodium perborate, or potassium monopersulfate; acid-based descaling agents such as citric acid, sulfamic acid, oxalic acid, or malic acid; surfactant-based cleaners such as quaternary ammonium salts, alkylbenzenesulfonates, or biodegradable alkyl polyglucosides; or combinations thereof. The tablets may be provided with a coating layer selected from polymeric coatings including polycaprolactone, polybutylene adipate terephthalate, polylactic acid, polyhydroxyalkanoates, ethylcellulose, polyurethane, and acrylic polymers, linear low density polyethylene, ethylene vinyl acetate; waxes and fatty substances including paraffin wax, carnauba wax, stearic acid, and fatty acid esters; or hybrid composite coatings comprising polymer-mineral blends, nanoclay-reinforced polymers, or wax-polymer mixtures. The coating layer may function to regulate water ingress, control dissolution of the active compounds, extend the duration of cleaning action, and reduce burst release phenomena, thereby enabling a more consistent and long-lasting sanitizing and cleaning effect in toilet bowl applications.

[0280] In at least one embodiment described herein, coated chemical tablets, briquettes, and pellets configured for controlled release of active agents in agricultural, household, environmental, or industrial applications are provided. The tablets may comprise, without limitation, fertilizer tablets including nitrogen, phosphorus, potassium, or micronutrient formulations; organic fertilizer and soil amendment tablets including bone meal, blood meal, seaweed extract, composted biomass, lime, gypsum, or sulfur; aquatic and animal care tablets including algaecide tablets, oxygen-releasing tablets, pond disinfectants, fishery treatment tablets, livestock salt licks, and trace mineral tablets; water treatment and disinfection tablets including trichloroisocyanuric acid tablets, sodium dichloroisocyanurate tablets, calcium hypochlorite tablets, oxygen donor tablets such as sodium percarbonate, sodium perborate, orpotassium monopersulfate, scale inhibitor tablets such as Citric acid, sulfamic acid, or malic acid tablets, and pH control tablets; household and sanitation tablets including toilet bowl cleaners, dishwashing tablets, descalers, deodorizing tablets, and fragrance-release tablets; and industrial and specialty chemical tablets including corrosion inhibitor tablets, biocide tablets for cooling towers, descaling tablets, rust remover tablets, oxygen scavenger tablets, and dye or colorant tablets, tablets made from quaternary ammonium compounds (Benzalkonium chloride (BAC), Didecyldimethylammonium chloride (DDAC), and Cetyltrimethylammonium bromide). The coating applied to such tablets may serve to regulate water ingress, modulate dissolution rate, reduce burst release, extend duration of action, and improve handling safety, thereby enabling a wide range of controlled-release applications outside of pharmaceutical systems.

[0281] For perforated, polymer-coated chlorine tablets (dichloro, trichloro, or hychlorite), release through the perforation can be accelerated with oxidizer-compatible, inorganic additives that draw in water, wick it to the core, or create fast-dissolving channels — without risking hazardous reactions. Suitable options include high-solubility salts as channeling / osmotic agents (sodium chloride, potassium chloride, sodium sulfate, potassium sulfate), hygroscopic salts to pull moisture (magnesium chloride, calcium chloride — used at low levels to avoid caking), and inorganic wicking / porous fillers (fumed silica, precipitated silica, diatomaceous earth, perlite, porous alumina, or zeolites) that form capillary networks leading from the perforation into the core. Upon wetting, the soluble salts dissolve to open micro-channels and raise osmotic flux, while the porous fillers maintain pathways for rapid ingress / egress, collectively shortening lag and boosting elution through the hole.

[0282] In at least one embodiment described herein, biocide tablets, briquettes, or pellets configured for controlled-release applications in water treatment, sanitation, aquaculture, livestock care, and industrial systems are provided. The biocide tablets may comprise, without limitation, chlorine-releasing compounds such as trichloroisocyanuric acid, sodium dichloroisocyanurate, calcium hypochlorite, or chlorinated lime; oxygen-releasing compounds such as sodium percarbonate, sodium perborate, or potassium monopersulfate; halogenbased hydantoin derivatives such as bromochlorodimethylhydantoin, 1-bromo-3-chloro-5,5- dimethylhydantoin, or dibromodimethylhydantoin; aldehyde-based compounds such as glutaraldehyde or paraformaldehyde; isothiazolinone biocides such as 5-chloro-2- methylisothiazolin-3-one, 2-methylisothiazolin-3-one, or benzisothiazolinone; quaternary ammonium compounds such as benzalkonium chloride, didecyldimethylammonium chloride, or cetyltrimethylammonium bromide; phenolic or oxidizing biocides including chlorophenols,cresols, or peracetic acid adducts; and metallic or sulfur-based biocides such as copper sulfate, silver salts, zinc pyrithione, copper pyrithione, or sulfur dioxide-releasing agents. The tablets may further be provided with a coating layer selected from polymeric, inorganic, or hybrid materials to regulate dissolution rate, minimize burst release, and extend the duration of antimicrobial action.

[0283] In certain embodiments, the over coating film comprises a fibre-intermeshed layer in which fibres are embedded or interlaced within a polymer matrix. The intermeshing creates micro-channels that increase the water vapor transmission rate (WVTR) compared to a homogeneous polymer film of equal thickness. Depending on fiber type and density, the WVTR may range from about 1-50 g / m2 / day, similar to polymer films, up to more than 1000 g / m2 / day in highly porous structures, thereby enabling tailored permeability and controlled nutrient release.Computer-Controlled Modular Coating System

[0284] In at least one embodiment described herein (see Figure 2), a modular coating system is provided that operates under computer-implemented control. The system comprises a conveyor system, a plurality of activity stations disposed along the conveyor system, one or more cavity plates (105) configured to house substrates (100), and a control unit including a processor executing software instructions stored on a non-transitory computer-readable medium. The control unit governs advancement, halting, and sequencing of the cavity plates through the activity stations to ensure precise processing of the substrates.System Overview

[0285] In one embodiment, the modular system comprises a conveyor frame supporting a conveyor belt or timing belt driven by servo motors. A plurality of cavity plates (105), each containing a plurality of cavities, is advanced along the conveyor through successive activity stations. Each station performs a predetermined programmed operation, which may include feeding substrates into cavities, unwinding and applying a polymer film, heat-softening the film, vacuum forming, trimming excess film, flipping substrates, applying a liquid coating, drying or curing, or perforating the coating layer.

[0286] The processor monitors cavity plate positions using sensors such as optical detectors, infrared sensors, proximity switches, or RFID tags. Feedback signals synchronize conveyor motion with activity execution, such that when a cavity plate is positioned beneath a station, the corresponding programmed activity is initiated.Homing and Positioning

[0287] In one embodiment, the cleats (704 on Figure 3) on the conveyor belt (703 on Figure 3) serve as positional references. Sensors detect cleat locations, enabling alignment to a designated home position. Any deviation between the detected and expected cleat position is corrected automatically.

[0288] Each activity station is mounted at a fixed position on the conveyor frame, and cleat positions are calibrated relative to these stations. Accordingly, the system ensures that cavity plates arrive in precise alignment beneath each activity station before processing begins. Servo-driven advancement and positional sensors maintain registration, providing smooth linear motion of multiple cavity plates in parallel. There is generally one cavity plate mounted between the two cleats on the conveyor belt.Control Method

[0289] The processor executes a control sequence that coordinates conveyor advancement with station operations. The sequence includes:1 . advancing a cavity plate to a station;2. halting the conveyor at the halt position;3. initiating the programmed operation onto the cavity plate or the substrate at that station;4. receiving a completion signal from the station; and5. advancing the plate to the next station upon receiving the competition signal from all the connected systems.

[0290] This cycle repeats across all activity stations. Multiple cavity plates may advance synchronously, enabling parallel processing for higher throughput.

[0291] At the end of a module, the processor determines whether the cavity plate is transferred to a subsequent module, discharged as finished product, or repositioned by a plate transfer station. Synchronization between multiple modules is achieved by coordinating servo-driven conveyors under a unified control unit, ensuring consistent cycle times and stable throughput.Software Implementation

[0292] Control instructions may be executed using PLC ladder logic, embedded C, or other industrial programming languages, stored on non-transitory media such as flash memory,EEPROM, or industrial hard drives. The processor may be a microcontroller, industrial PC, or PLC-based unit.

[0293] The processor integrates conveyor motion with station-specific controls — for example, actuating solenoid valves for vacuum suction, triggering relays or PID controllers for heaters, or synchronizing pneumatic cylinder operation.

[0294] In certain embodiments, a user interface allows operators to activate or deactivate specific stations via software without hardware modification, enabling rapid customization of coating sequences.Cycle Time Control

[0295] In one embodiment, conveyor advancement is governed by a fixed cycle time defined by the station requiring the longest operation. The conveyor halts for this interval, after which it advances a predetermined distance to align the cavity plate with the next station. If a plate is absent or cavities are unfilled, the station transmits an automatic completion signal, maintaining system synchronization without interrupting the cycle.Advantages

[0296] Embedding process coordination into computer-implemented control may provide:1 . precise synchronization of conveyor motion and coating activities;2. adaptability to different substrate types and coating requirements without hardware redesign;3. improved reliability through error detection and recovery routines;4. scalability through synchronized operation of multiple modules; and5. modular flexibility, allowing identical or different stations to be arranged in series as required.Numbering System Used

[0297] 100-solid substrate, 101-first coating layer, 102-second coating layer, 103-partially coated fertilizer, 104-fully coated substrate, 105-cavity plate, 106-cavities, 107-cavity step, 108-cavity bottom hole, 109-hole for cavity plate alignment, 102-coated substrate with a perforation, 116-perforation in the coating, 115-solid substrate (1), 117-perforated coating, 121 -coated substrate having perforation and overcoating, 122-overcoating, 123-coated substrate with thinned out area, 124-thinned out area, 125-coating that has been thinned out,128-perforating plate, 127-pin for perforation, 200-feeding station, 201 -feeding hopper, 202- substrate scrapper, 203-collection bin, 204-holler valve, 205-gravity chute, 300-fil application station, 301 -film roll, 302-film roll stand, 303-film pinning roller, 350-350 unwinder station, 351 - film roll, 352-servo motor and drive, 353-film unwinding roller, 354-mounting bracket, 400-film heating system, 401 -heat applicator, 402-baffle, 403-pinning roller heat station, 450-heatign station embodiment, 456 / 458-pneumatic cylinders, 454-heating system, 453-baffles, 459- mounting bracket, 500-vacuum station, 501 -vacuum plate, 502-platform for substrate, 503- vacuume port, 504-vacuume box, 505- pneumatic cylinder Vac, 506- pneumatic cylinder vac2, 507-vacuume box guide rail, 508-vacuum box guide rail, 509-vacuume plate and cavity plate alignment pin, 550-substrate lifting apparatus, 551 -plastform mounting plate, 553-platform, 554-pneumatic cylinder, 556-mounting bracket for mounting apparatus, 600-excess film cutting station, 601 -cutting die holding plate, 602-round die punch, 603 / 604-pneumatic cylinders for moving plate, 650-cutting station, 651 -cutting die plate, 652-cutting die punches, 653 / 654 -pneumatic cylinders, 655-vibration motor, 656-mounting bracket, 700-modular coating conveyor system, 701-first conveyor system, 702-second conveyor system, 703- conveyortiming belt, 704-cleats on the timing belt, 705-conveyor pully, 706-shaft for pully, 707- servo motor and drive system to run the conveyor belt, 708-support bracket for timing belt, 709-frame beams, 710-cross beams, 711 -anchor plates, 712-frame legs, 713 / 713a-cavity plate transfer system, 715-vacuum suction cups, 800-substrate flipping apparatus, 801 / 802- Robotic arms of the flipping apparatus, 803-cavity plate lifting plate, 804 / 805-pneumatic cylinders for lifting the plate, 806-excess film collection station, 900-coated substrate collection system, 1000-stand-alone substrate coating apparatus, 1001-heating system, 1002 / 1002a- arms for mounting heating system, 1003-film roll, 1004-polymer film, 1005-guide rails for moving the heater, 1006-pinning rollers, 1007-coating cavity plate, 1008-frame for holding cavity plate, 1009-vacuum box, 1010-pneumatic cylinders, 1011 -guide rail for moving the vacuum box, 1012-platform, 1013-platform, 1014-frame structure, 1015-arms for connecting vacuum box, 1016-vacuume port.

[0298] While the above description provides examples of one or more apparatus, methods, or systems, it will be appreciated that other apparatus, methods, or systems may be within the scope of the claims as interpreted by one of skill in the art.

Claims

CLAIMSWhat is claimed is:1 . A method of producing polymer-coated substrates using an intermittent substrate coating system, the method comprising: a. advancing and halting a substrate holder at a plurality of activity stations mounted along the length of the conveyor system, each activity station being configured to perform one or more coating-related operation on the substrates; and b. performing the following coating-related operations at the activity stations: i. feeding solid substrate into the substrate holder at a feeding station; ii. applying a first polymer film at a first film application station;Hi. heating and wrapping the first polymer film around the substrates at a first coating station to form partially coated substrates; iv. severing and collecting portions of the first film not adhered to the substrates at a first excess film cutting and collection station; v. inverting the partially coated substrates at a flipping station to expose uncoated surfaces thereof; vi. applying a second polymer film at a second film application station; and vii. heating, softening, and wrapping the second polymer film around the partially coated substrates at a second coating station to form fully coated substrates; thereby producing a polymer-coated substrate comprising at least two polymer film layers including a sealing layer.

2. The method of claim 1 , further comprising performing the following coating-related operations at the activity stations: i. severing and collecting portions of the second film not adhered to the substrates at a second excess film cutting and collection station; ii. applying a liquid polymer coating at a liquid coating application station and drying the applied coating at an associated drying station;Hi. applying a wax overcoat layer at a wax overcoating station; iv. introducing perforations into the coating at a micro-perforation station; and v. collecting the coated substrates at a collection station.

3. The method of claim 1 or claim 2, wherein the conveyor system includes one or more parallel conveyor frames, the one or more parallel conveyor frames comprising at least two conveyor frames arranged side by side.

4. The method of claim 3, wherein a pair of plate transfer units is positioned at opposite ends of the parallel conveyor frames, the plate transfer units being configured to transfer the coating cavity plates between the conveyor frames when the plurality of coating cavity plates are detachably mounted on the conveyor frames.

5. The method of claim 2, wherein the plate transfer units comprise rotary, linear, or pick-and-place transfer mechanisms configured to transfer the coating cavity plates between conveyor frames in an endless loop.

6. The method of claim 1 , wherein each of the plurality of activity stations is independently mountable, removable, or reconfigurable along the conveyor frames.

7. The method of claim 1 , wherein the first coating station comprises a heating element and a wrapping mechanism configured to wrap the heat-softened film around the substrates.

8. The method of claim 1 , wherein the excess film cutting station comprises a cold punching die, a hot punching die, a hot air knife, and a vacuum system in combination, configured to sever and remove portions of the polymer film not adhered to the surface of the substrate.

9. The method of claim 1 , wherein the flipping station comprises an apparatus configured to invert the partially coated substrates within the same cavity of a cavity plate or into a different cavity of a different cavity plate.

10. The method of claim 2, wherein the liquid coating application station comprises a liquid polymer applicator selected from a foam pad, fibrous roller, spray nozzle, or porous applicator, and a drying mechanism selected from heating, vacuum, infrared irradiation, ultraviolet irradiation, or forced air.11 . The method of claim 2, wherein the wax overcoating station is configured to apply one or more wax layers, the wax layers comprising natural wax, synthetic wax, or blends thereof.

12. The method of claim 2, wherein the micro-perforating station comprises one or more needles, pins, or laser perforators configured to generate controlled perforations in the coating.

13. The method of claim 2, wherein the collection station comprises an automated ejector system or receptacle for receiving the coated substrates after processing.

14. The method of claim 1 , wherein the activity stations are arranged in series along each conveyor frame to provide sequential multi-layer coating of the substrates.

15. The method of claim 1 , wherein the apparatus is modular and configured such that additional conveyor frames or activity stations may be added to scale production capacity or enable additional coating operations.

16. An apparatus for coating solid substrates, the apparatus comprising: a. one or more parallel conveyor frames arranged side by side; b. a plurality of coating cavity plates mounted on the conveyor frames; c. a pair of plate transfer units positioned at opposite ends of the parallel conveyor frames, the plate transfer units being configured to transfer the coating cavity plates between the conveyor frames; and d. a plurality of activity stations mounted on one or more of the conveyor frames, the activity stations being configured to perform predetermined activities on the solid substrates, wherein the plurality of activity stations includes: i. a feeding station configured to feed the solid substrates into the coating cavity plates; ii. a film unwinding station configured to apply one or more coating films;Hi. a film coating station configured to heat and wrap the heat-softened coating films around the solid substrates; iv. an excess film cutting station configured to sever and collect portions of film not adhered to the substrates; v. a flipping station configured to invert the partially coated substrates; vi. a second film application station configured to apply a second polymer film to the partially coated substrates; and vii. a second coating station to heat, soften, and wrap the second polymer film around the partially coated substrates at to form fully coated substrates.

17. The apparatus of claim 16, wherein the plurality of activity stations also includes:i. a liquid coating and drying or curing station configured to apply a liquid coating and dry or cure the coating; ii. a wax overcoating station configured to apply a wax overcoat onto the coated substrates;Hi. a micro-perforating station configured to perforate the coating; and iv. a collection station configured to collect the coated substrates.

18. The apparatus of claim 16 or claim 17, wherein the one or more parallel conveyor frames comprise at least two conveyor frames arranged side by side.

19. The apparatus of any one of claims 16 to 18, wherein the coating cavity plates are detachably mounted on the conveyor frames.

20. The apparatus of any one of claims 16 to 18, wherein the plate transfer units comprise rotary, linear, or pick-and-place transfer mechanisms configured to transfer the coating cavity plates between conveyor frames in an endless loop.21 . The apparatus of any one of claims 16 to 18, wherein each of the plurality of activity stations is independently mountable, removable, or reconfigurable along the conveyor frames.

22. The apparatus of any one of claims 16 to 18, wherein the film coating station comprises a heating element and a wrapping mechanism configured to wrap the heat- softened film around the substrates.

23. The apparatus of any one of claims 16 to 18, wherein the flipping station comprises an apparatus configured to invert the partially coated substrates within the same cavity of a cavity plate or into a different cavity of a different cavity plate.

24. The apparatus of claim 17 or claim 18, wherein the liquid coating and drying or curing station comprises a liquid polymer applicator selected from a foam pad, fibrous roller, spray nozzle, or porous applicator, and a drying mechanism selected from heating, vacuum, infrared irradiation, ultraviolet irradiation, or forced air.

25. The apparatus of claim 17 or claim 18, wherein the wax overcoating station is configured to apply one or more wax layers, the wax layers comprising natural wax, synthetic wax, or blends thereof.

26. The apparatus of claim 17 or claim 18, wherein the micro-perforating station comprises one or more needles, pins, or laser perforators configured to generate controlled perforations in the coating.

27. The apparatus of claim 17 or claim 18, wherein the collection station comprises an automated ejector system or receptacle for receiving the coated substrates after processing.

28. The apparatus of any one of claims 16 to 27, wherein the activity stations are arranged in series along each conveyor frame to provide sequential multi-layer coating of the substrates.

29. The apparatus of any one of claims 16 to 28, wherein the apparatus is modular and configured such that additional conveyor frames or activity stations may be added to scale production capacity or enable additional coating operations.

30. A polymer-coated substrate comprising: a. a solid substrate; b. a polymer coating covering substantially the entire surface of the solid substrate, the polymer coating having a water vapor transmission rate (WVTR) between 0.1 g / m2day and 2000 g / m2day; and c. one or more perforations extending through the polymer coating, wherein the polymer-coated substrate is configured to release the substrate substantially through the perforations over an extended period of time.

31. The polymer-coated substrate of claim 30, wherein the solid substrate comprises a fertilizer tablet, pharmaceutical core, biocide pellet, detergent tablet, water treatment tablet, or agrochemical pellet.

32. The polymer-coated substrate of claim 30 or claim 31 , wherein the first polymer layer and the second polymer layer each comprise a polymer selected from the group consisting of aliphatic polyesters, including but not limited to polylactic acid (PLA), polyglycolic acid (PGA), poly(lactic-co-glycolic acid) (PLGA), polycaprolactone (PCL), poly(butylene succinate) (PBS), poly(butylene succinate-co-adipate) (PBSA), poly(butylene succinate-co-terephthalate) (PBST), poly(butylene adipate-co-terephthalate) (PBAT), polyethylene succinate) (PESu), polypropylene succinate) (PPSu), poly(butylene carbonate) (PBC), poly(trimethylene carbonate) (PTMC), polyethylene carbonate) (PEC), and copolymers thereof; polyhydroxyalkanoates (PHAs), including poly(3-hydroxybutyrate) (PHB), poly(3- hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(3-hydroxyhexanoate) (PHHx), poly(3-hydroxyoctanoate) (PHO), poly(3-hydroxydodecanoate) (PHD), poly(4-hydroxybutyrate) (P4HB), and copolymers or blends thereof; starch-based polymers, including thermoplastic starch (TPS) and starch blended with polyesters such as PBAT or PCL; cellulose-based polymers, including regenerated cellulose, cellulose acetate, cellulose acetate butyrate, carboxymethyl cellulose, hydroxypropyl cellulose, and ethyl cellulose; protein-based biopolymers, including zein, soy protein isolate, wheat gluten, gelatin, and collagen; polysaccharide-based biopolymers, including chitosan, alginate, pectin, pullulan, xanthan gum, gellan gum, and hyaluronic acid; and other biodegradable polymers, including polyethylene oxide), degradable polyethylene glycol (PEG) derivatives, polyvinyl alcohol (PVA), polyethylene furanoate) (PEF), poly(butylene furanoate) (PBF), degradable polyurethane, silk fibroin. In some embodiments, the coating films may comprise water-soluble polymers that dissolve under controlled aqueous conditions to facilitate nutrient release. Suitable examples include polyvinyl alcohol (PVA), available in both cold-water soluble and hot-water soluble grades.

33. The polymer-coated substrate of any one of claims 30 to 32, wherein at least one of the first or second polymer layers has a thickness in the range of 10 pm to 2000 pm.

34. The polymer-coated substrate of any one of claims 30 to 33, further comprising a wax overcoat layer disposed over the first polymer layer, the second polymer layer, or both.

35. The polymer-coated substrate of any one of claims 30 to 34, further comprising a liquid- applied barrier polymer coating disposed over the first polymer layer, the second polymer layer, or both.

36. The polymer-coated substrate of any one of claims 30 to 35, wherein the one or more perforations have diameters in the range of 1 pm to 500 pm.

37. The polymer-coated substrate of any one of claims 30 to 36, wherein the one or more perforations are arranged in a predetermined pattern to control diffusion of water or active ingredients.

38. The polymer-coated substrate of any one of claims 30 to 37, wherein the perforations are introduced by laser perforation, micro-needle puncturing, or mechanical punching.

39. The polymer-coated substrate of any one of claims 30 to 38, wherein the polymer layers are configured to provide a controlled release of the substrate contents when exposed to water, soil, or biological media.

40. The polymer-coated substrate of any one of claims 30 to 39, wherein the solid substrate has a largest dimension in the range of 2 mm to 200 mm.

41. The polymer-coated substrate of any one of claims 30 to 40, wherein the polymer- coated substrate is configured for use in soil, hydroponic, or soilless growing systems.

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