Biodegradable coatings, coated particles, and methods for producing the same

Abstract

Biodegradable coatings, particles coated with such biodegradable coatings, and methods for making such coatings and coated particles. Coatings with urethane linkages, urea linkages, or combinations thereof can be degradable over time by a microbial powder or solution applied to the particles between layers of the coating or on top of the coating.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 435,665, filed December 28, 2022, the entire disclosure of which is incorporated herein by reference in its entirety.

[0002] The present disclosure generally relates to coatings for particles that degrade over time. More specifically, the present disclosure relates to coatings and coated particles containing such coatings that provide protection to underlying particles when planted in soil, submerged in water, or floating on water, and degrade when such protection is no longer desired or necessary. Additionally, the present disclosure relates to methods for producing biodegradable coatings and coated particles using specially formulated microbial consortia impregnated within or applied thereon. [Background technology]

[0003] Many fertilizers are used in the form of granular materials and are water-soluble, such as urea-containing fertilizers. Such fertilizers may contain core particles containing primary nutrients, such as nitrogen (N), phosphorus (P), or potassium (K), or a combination of these elements. Primary nutrients are generally in a form that has good solubility in water. Therefore, in moist or wet environments, primary nutrients may be rapidly washed away into the soil, migrate away from the plant before the plant can take them up, or decompose rapidly. Often, runoff or decomposition results in a loss of approximately 40 to 60% of the fertilizer applied to the crop. One way to improve plant uptake of primary nutrients is to modify fertilizer products to provide sustained release from controlled-release fertilizers.

[0004] In this embodiment, the controlled-release fertilizer releases nutrients over time to meet the nutritional needs of the crop. One method for achieving controlled-release fertilizer is to apply a coating layer (typically a polymer coating layer). There are many types of controlled-release polymer-coated fertilizers used worldwide, such as urea-formaldehyde products such as sulfur-coated urea, polymer-coated urea, and methylene urea. The advantages of using polyurethane-coated controlled-release fertilizers are numerous, including higher nutrient content, consistent and predictable nutrient release rates, and flexibility in various climates. As a result, in 2019, the global demand for controlled-release fertilizers was estimated at 920 kilotons, and the global market for controlled-release fertilizers is expected to grow by more than 5% by 2026, from an estimated $2.4 billion in 2021.

[0005] Similarly, current efforts are being made to enhance agricultural approaches to growing crops. For example, agricultural manufacturers are exploring ways to apply protective coatings to seeds so that crops can be grown in various geographic regions and / or planted well in advance of the growing season. Because soil is the primary recipient of these coated fertilizers and seeds, the empty coating shells of these products that remain in the soil at the end of their useful life are of growing environmental concern. In fact, of the 359 million metric tons of plastics produced worldwide in 2018, 12.5 million metric tons were used annually in agricultural production, with coated fertilizers accounting for approximately 6.7% of this total.

[0006] Sustainable materials are an important area of ​​interest in agricultural products, but efforts are still in their infancy. For example, biodegradable polymers are being evaluated as potential alternatives to coated fertilizers. However, there are misconceptions about biodegradability, and biodegradability can prove limited. In particular, there is a perception that because a product is made from biodegradable materials, the environment in which the product is disposed of is irrelevant and unimportant. Rather, the environment to which the material is exposed plays a role in the rate and / or effectiveness of degradation. In fact, certain environmental requirements are essential for the biodegradation process, such as moisture level, sunlight exposure, soil and compost content, oxygen availability, and the presence of microorganisms. For example, biodegradation requires microorganisms to convert broken-down polymer molecules, i.e., microplastics, into small molecules such as carbon dioxide, water, and organic matter. Furthermore, plastic biodegradation becomes even more difficult when microplastics are present in pond water, rivers, or streams, where the microbial species are far different from those found in soil.

[0007] Furthermore, while biodegradable plastics are typically used in processes that require injection molding, extrusion, or pressing solidified polymer pellets into rigid, semi-rigid, or flexible products, the physical properties associated with the use of biodegradable polymers pose numerous challenges when attempting to use these materials as coatings for fertilizers, seeds, and other agricultural products. For example, biodegradable polymers typically have very high melting temperatures that can damage or degrade the agricultural particles being coated. Furthermore, even if the underlying particles survive the coating process, any resulting coatings can be brittle, powdery, and weak. Finally, particles coated with currently known biodegradable plastics are less effective at controlling the release of underlying particles compared to traditional polyurethane coating products. Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, there is a need for a coating solution that provides the same or improved level of protection and controlled release of underlying agricultural particles, where applicable, as conventional polyurethane coatings, but that can degrade after its useful life. The present disclosure provides such coating solutions, particles coated with such coating solutions, and methods for making such coatings and coated particles. [Means for solving the problem]

[0009] The present disclosure relates to degradable coating shells for agricultural particles such as fertilizers and seeds. More specifically, the coatings can incorporate microbial consortia capable of degrading the polymer-based layer(s) of the coating shell. As a result, the polymer layer(s) contained in the coating decompose into carbon dioxide, water, and organic matter after the particles deliver nutrients to plants in a controlled manner (in the case of fertilizers) or burst for germination (in the case of seeds). This degradation is not impaired by the environment; i.e., whether the coated particle is in soil or water, each coated particle contains a sufficient amount of microbial consortium to effectively degrade the polymer layer(s). In fact, the microbial consortium and the polymer layer(s) are synergistic for the degradation process, in that the polymer layer(s) protect the microorganisms from the environment while slowly releasing the microorganisms to the surface of the polymer. Without being bound by any particular theory, this slow release allows the microbial colony to grow and replenish until all the polymer is degraded.

[0010] In some embodiments, the microbial consortium is added to the surface of the uncoated particle before applying one or more polymer layers. In other embodiments, the microbial consortium is incorporated between polymer layers, where a first polymer layer is added to the surface of the uncoated particle. In yet other embodiments, the microbial consortium is applied on top of the polymer layer(s).

[0011] In some embodiments, the microbial consortium is applied onto a carrier powder. For example, the microbial consortium-containing carrier powder can be applied to the surface of an uncoated particle, between polymer layers, or on top of a polymer layer. In other embodiments, the microbial consortium can be in liquid form. For example, the microbial consortium-containing liquid can be applied to the surface of an uncoated particle, between polymer layers, or on top of a polymer layer. This application can be achieved by dipping, spraying, etc.

[0012] The present disclosure also relates to coated particles comprising a core and a coating shell, the coating shell comprising: a first coating layer disposed on the core and comprising a coating formulation and a wax; a carrier powder impregnated with microorganisms capable of degrading the coating formulation and wax and applied to the first coating layer; and a second coating layer disposed on the carrier powder and comprising the coating formulation. In some embodiments, the core comprises fertilizer. In other embodiments, the core comprises seeds. In still other embodiments, the coating formulation comprises polyurethane. In still other embodiments, the coating shell further comprises a third coating layer disposed between the first coating layer and the carrier powder and comprising the coating formulation and a wax; and a fourth coating layer disposed between the carrier powder and the second coating layer and comprising the coating formulation and a wax.

[0013] The present disclosure also relates to coated particles comprising a core, a carrier powder impregnated with a microorganism and applied to the core, a coating shell comprising a first coating layer comprising a coating formulation and a wax disposed on the carrier powder, and a second coating layer comprising the coating formulation and disposed on the first coating layer, wherein the microorganism is capable of degrading the coating formulation and the wax. In some embodiments, the core comprises fertilizer. In other embodiments, the core comprises seeds. In yet other embodiments, the coating formulation comprises polyurethane.

[0014] The present disclosure also relates to coated particles comprising a core, a first coating layer disposed on the core and comprising a coating formulation, and a coating shell impregnated with microorganisms capable of degrading the coating formulation and wax, the coating shell comprising a carrier powder applied to the first coating layer. In some embodiments, the core comprises fertilizer. In other embodiments, the core comprises seeds. In yet other embodiments, the coating formulation comprises polyurethane.

[0015] The present disclosure also relates to coated particles comprising a core, a coating layer disposed on the core, the coating layer comprising a coating formulation and accounting for about 0.5 to about 5% of the total coated particle weight, and a coating shell disposed on the coating layer, the coating shell comprising a microbial consortium and a solution that enables the microbial consortium to degrade the coating formulation. In some embodiments, the core comprises fertilizer. In other embodiments, the core comprises seeds. In still other embodiments, the coating formulation comprises polyurethane.

[0016] The present disclosure also relates to coated particles comprising a core, a coating layer disposed on the core, the coating layer comprising a coating formulation and accounting for about 0.5 to about 5% of the total coated particle weight, and a coating shell impregnated with microorganisms capable of degrading the coating formulation, the coating shell comprising a carrier powder applied to the coating layer. In some embodiments, the core comprises fertilizer. In other embodiments, the core comprises seeds. In yet other embodiments, the coating formulation comprises polyurethane.

[0017] The present disclosure also provides Coated particles, The core and a first coating layer disposed on the core, the first coating layer comprising a coating formulation and a wax; a carrier impregnated with a microbial consortium and applied with a first coating layer in an amount of about 0.1 to about 1.0% by weight of the coated particles; and a second coating layer disposed on the carrier and comprising the coating formulation; a coating shell comprising: and having a functional period, wherein the microbial consortium comprises a plurality of microorganisms capable of substantially biodegrading the coating shell within a target period, the target period being about 48 months or less after the end of the functional period.

[0018] In some aspects, the core comprises fertilizer. In other aspects, the core comprises seeds. The coating formulation can comprise polyurethane. In some embodiments, the polyurethane is a reaction product of a polyisocyanate and a polyol. In other embodiments, the plurality of microorganisms comprises a first set of microorganisms capable of degrading the coating formulation and a second set of microorganisms capable of degrading wax. In some aspects, the plurality of microorganisms comprises at least two or more microorganisms classified as Biosafety Level 1 organisms.

[0019] In yet other embodiments, the coating shell further comprises a third coating layer disposed between the first coating layer and the carrier, the third coating layer comprising the coating formulation and a wax, and a fourth coating layer disposed between the carrier and the second coating layer, the fourth coating layer comprising the coating formulation and a wax. In some aspects, the carrier may be a powder.

[0020] The present disclosure also provides The core and a carrier impregnated with a microbial consortium and applied to said core; a first coating layer disposed on the carrier, the first coating layer comprising a coating formulation and a wax; and a second coating layer comprising the coating formulation and disposed on the first coating layer; a coating shell comprising: A coated particle comprising: The present invention relates to coated particles having a functional period, wherein the microbial consortium is capable of substantially degrading the coating shell within about 48 months or less after the end of the functional period.

[0021] In some aspects, the core comprises fertilizer. In other aspects, the core comprises seeds. The coating formulation can comprise polyurethane. In some embodiments, the microbial consortium comprises a first set of microorganisms capable of degrading the coating formulation and a second set of microorganisms capable of degrading the wax. In other embodiments, the carrier is a powder.

[0022] The present disclosure also provides The core and a first coating layer disposed on the core, the first coating layer comprising a coating formulation; and a carrier powder disposed on the first coating layer and impregnated with a microbial consortium; a coating shell comprising: A coated particle comprising: The present invention relates to coated particles having a functional period, wherein the microbial consortium comprises a plurality of microorganisms capable of substantially degrading the coating shell within a target period, the target period being no more than about 48 months after the end of the functional period.

[0023] In some aspects, the core comprises fertilizer. In other aspects, the core comprises seeds. In some embodiments, the coating formulation comprises polyurethane. In other embodiments, the polyurethane is a reaction product of a polyisocyanate and a polyol. In yet other embodiments, the plurality of microorganisms comprises a first set of microorganisms capable of degrading the coating formulation and a second set of microorganisms capable of degrading wax. In yet other embodiments, the plurality of microorganisms comprises at least two microorganisms classified as Biosafety Level 1 organisms.

[0024] Further features and advantages can be seen from the following detailed description provided in conjunction with the drawings listed below. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a cross-sectional view of a coated particle according to one embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view of a coated particle according to another embodiment of the present disclosure. [Figure 3] FIG. 2 is a cross-sectional view of a coated particle according to yet another embodiment of the present disclosure. [Figure 4] FIG. 1 is a graphical representation of the biodegradation of the coating shell of a coated particle formed according to one embodiment of the present disclosure. [Figure 5] FIG. 10 is a graphical representation of the biodegradation of the coating shell of a coated particle formed according to another embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0026] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure pertains. Terms, such as those defined in commonly used dictionaries, should be interpreted to have a meaning consistent with their meaning in the context of this specification, and should not be interpreted in an idealized or overly formal sense unless explicitly defined as such in this specification. Well-known functions or structures may not be described in detail for the sake of brevity or clarity.

[0027] The terms "about" and "approximately" are generally intended to mean an acceptable degree of error or variation in the quantity measured, given the nature or precision of the measurements. Numerical quantities given in this description are approximate unless otherwise specified, meaning that the term "about" or "approximately" can be inferred when not expressly stated.

[0028] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well (i.e., "at least one") unless the context clearly dictates otherwise.

[0029] Terms such as "first," "second," and the like are used herein to describe various features or elements, but these features or elements should not be limited by these terms. These terms are used only to distinguish one feature or element from another. Thus, a first feature or element described below could be referred to as a second feature or element, and similarly, a second feature or element described below could be referred to as a first feature or element without departing from the teachings of the present disclosure.

[0030] Terms such as "at least one of A and B" should be understood to mean "A only, B only, or both A and B." The same construction should apply to longer lists (e.g., "at least one of A, B, and C").

[0031] The term "consisting essentially of" means that in addition to the recited elements, the claimed thing may also include other elements (steps, structures, ingredients, components, etc.) that do not adversely affect the operability of the claimed thing for its intended purpose as described in this disclosure. This term excludes other elements that adversely affect the operability of the claimed thing for its intended purpose as described in this disclosure, even if such other elements may enhance the operability of the claimed thing for some other purpose.

[0032] As used herein, the term "over" refers to some layer, coating, or component that is further from the center of the particle than another. For example, "X is over Y" should be interpreted to mean that X is further from the center of the particle than Y. X may be in direct contact with Y ("directly over"), or there may be intervening distances and / or components. It is contemplated that any instance of the term "over" can be limited to "directly over."

[0033] The present invention describes the combined ability of coated particles to be slowly released (in the case of fertilizers and at a rate suited to plant requirements) or burst in a controlled manner (in the case of seeds and at an appropriate germination time), and once released, the microbial consortium described herein impregnated within or on the surface of the coating biodegrades the residual polymer layer of the coating shell. Furthermore, according to at least one embodiment, when the microbial consortium is protected by at least one polymer layer, the microorganisms are slowly released to the surface due to substantial degradation (this term is discussed below) of the polymer layer of the coating shell. The sustained release of the microorganisms ensures that the microbial colony continues to grow and replenish until all of the polymer layer(s) of the coating shell are substantially degraded.

[0034] lower layer particles As previously mentioned, the present disclosure relates to coated particles, wherein the coating is degradable over time. The sublayer particles can be agricultural particles. In some embodiments, the agricultural particles can be granular fertilizers. In this aspect, the granular fertilizers can include primary nutrients. The primary nutrients can be present in an amount of about 1 to about 99% by weight based on the total weight of the coated particles. In one embodiment, the primary nutrients are present in an amount of about 1 to about 50% by weight based on the total weight of the coated particles. In another embodiment, the primary nutrients are present in an amount of about 51 to about 99% by weight based on the total weight of the coated particles.

[0035] Primary nutrients may include one or more nitrogen (N), phosphorus (P), and / or potassium (K) compounds. Nitrogen compounds may include, but are not limited to, urea, ammonium nitrate, ammonium sulfate, calcium nitrate, diammonium phosphate, monoammonium phosphate, potassium nitrate, sodium nitrate, and combinations thereof. Phosphorus compounds may include, but are not limited to, diammonium phosphate, monoammonium phosphate, monopotassium phosphate, dipotassium phosphate, tetrapotassium pyrophosphate, potassium metaphosphate, single superphosphate, triple superphosphate, calcium phosphate, and combinations thereof. Potassium compounds may include, but are not limited to, potassium chloride, potassium nitrate, potassium sulfate, monopotassium phosphate, dipotassium phosphate, tetrapotassium pyrophosphate, potassium metaphosphate, and combinations thereof.

[0036] In some embodiments, the N:P:K ratio can range from 10:0:4 to 30:15:25. For example, the N:P:K ratio can be 29:3:4, 22:7:10, 21:7:14, 20:5:10, 18:6:18, 16:4:8, 15:15:15, 13:13:13, 12:6:24, 10:10:10, 15:0:15, 15:5:10, 22:3:14, 20:28:5, or 12:6:6.

[0037] In another embodiment, the sub-layer particles also contain secondary nutrients. In this embodiment, the secondary nutrients may be present in an amount of about 0.5 to about 15% by weight based on the total weight of the coated particles. For example, the secondary nutrients may be present in an amount of about 5 to about 10% by weight based on the total weight of the particles. The secondary nutrients are not particularly limited. In one embodiment, the secondary nutrients are calcium (Ca), magnesium (Mg), sulfur (S), or a combination thereof. Non-limiting examples of calcium include calcium sulfate, calcium chloride, calcium carbonate, calcium silicate, calcium phosphate, and combinations thereof. Non-limiting examples of magnesium include magnesium sulfate, magnesium chloride, magnesium oxide, magnesium carbonate, and combinations thereof. Non-limiting examples of sulfur include elemental sulfur, sulfates such as ammonium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, and combinations thereof.

[0038] In yet another embodiment, the sublayer particles also contain micronutrients. In this aspect, the micronutrients may be present in amounts less than the primary nutrients, or, if present, the secondary nutrients. In one embodiment, the micronutrients are present in an amount of about 0.01 to about 5.0 wt.% based on the total weight of the coated particles. In another embodiment, the micronutrients are present in an amount of about 0.1 to about 2.0 wt.% based on the total weight of the coated particles. Suitable micronutrients include, but are not limited to, zinc (Zn), boron (B), iron (Fe), manganese (Mn), nickel (Ni), copper (Cu), molybdenum (Mo), chlorine (Cl), and combinations thereof. The zinc may be in the form of, for example, one or more of zinc chelate, zinc chloride, zinc oxide, zinc sulfate, zinc oxysulfate, and combinations thereof. Boron can be in the form of, for example, boric acid, sodium borate, sodium tetraborate, sodium octaborate, sodium metaborate, potassium borate, potassium tetraborate, potassium octaborate, potassium metaborate, and combinations thereof. Iron can be in the form of, for example, iron chelate, iron chloride, iron nitrate, iron oxalate, iron sulfate, and combinations thereof. Manganese can be in the form of, for example, manganese chelate, manganese chloride, manganese oxide, manganese sulfate, and combinations thereof. Nickel can be in the form of, for example, nickel chelate, nickel nitrate, nickel sulfate, and combinations thereof. Copper can be in the form of, for example, copper chelate, copper chloride, copper oxide, copper sulfate, and combinations thereof. Molybdenum can be in the form of, for example, ammonium molybdate, sodium molybdate, etc. Chloride can be in the form of, for example, calcium chloride, copper chloride, iron chloride, magnesium chloride, manganese chloride, potassium chloride, zinc chloride, and combinations thereof. The form of the micronutrients is not particularly limited, and may be, for example, granules, crystals, powder, or a concentrated solution, suspension, colloid, slurry, paste, or a combination thereof.

[0039] In other embodiments, the sublayer particles can be any seeds used to grow crops.In this aspect, suitable seeds include, but are not limited to, soybean seeds, cottonseed seeds, sunflower seeds, canola seeds, corn seeds, rapeseed seeds, peanut seeds, and other commercially cultivated fruits and vegetables.Seeds can also include wheat, barley, milo, alfalfa, sorghum, cereals (cereals), clover, sowgrass, timothy grass, oats, bermuda, bluegrass, and rye.

[0040] The coated sub-layer particles can have a particle size of about 0.10 mm to about 25 mm, e.g., about 0.5 mm to about 20 mm, about 1 mm to about 15 mm, about 3 mm to about 10 mm, or about 5 mm to about 11 mm. In this embodiment, at least about 80% of the coated sub-layer particles have an average particle size within the above range. In some embodiments, the average size of the sub-layer particles is at least about 85% of the average size of the coated particles. In other embodiments, the average size of the sub-layer particles is at least about 95% of the average size of the coated particles. In yet other embodiments, the average size of the sub-layer particles is at least about 99.5% of the average size of the coated particles.

[0041] In some embodiments, the average weight of the underlayer particles is at least about 80% of the average weight of the coated particles. In other embodiments, the average weight of the underlayer particles is at least about 85% of the average weight of the coated particles. In yet other embodiments, the average weight of the underlayer particles is at least about 90% of the average weight of the coated particles. In yet other embodiments, the average weight of the underlayer particles is at least about 95% of the average weight of the coated particles. In yet other embodiments, the average weight of the underlayer particles is at least about 98% of the average weight of the coated particles. In yet other embodiments, the average weight of the underlayer particles is at least about 99% of the average weight of the coated particles.

[0042] Coating Compounds The coating may be formed from a coating formulation including one or more coating components. In one embodiment, the coating is water-impermeable. In another embodiment, the coating is semi-permeable, and when applied to the underlying particle, prevents release of the underlying particle until needed. For example, if the underlying particle is a fertilizer and the coating is semi-permeable, both water and fertilizer will move through the coating by diffusion.

[0043] In one embodiment, the coating component is a polymer. In another embodiment, the polymer(s) may be crosslinked. In this aspect, the polymer may be thermosetting. In yet another embodiment, the polymer may be thermoplastic. Non-limiting examples of polymers suitable for use in forming the coating formulation are water-insoluble polymers. In this aspect, the polymer may have a solubility of less than about 0.10 g / L in deionized water at 100 kPa and 20°C. For example, the solubility of the polymer may be less than about 0.05 g / L in deionized water at 100 kPa and 20°C. In one embodiment, the polymer has a solubility of less than about 0.01 g / L in deionized water at 100 kPa and 20°C. In another embodiment, the polymer is insoluble in deionized water at 20°C using the method outlined in D. Braun et al., Practical Macromolecular Organic Chemistry, CRC Press, 1984, p. 73, in which 30-50 mg of a finely divided polymer sample is placed in a small test tube containing 1 ml of liquid and left for several hours. In some embodiments, the coating comprises a resin. In this regard, the coating may comprise one or more polymers and / or one or more additives.

[0044] In one embodiment, the coating is a polyurethane coating. In this aspect, the ratio of NCO to OH groups can range from 0.8:10 to 1.2:10. The components of such polyurethane coatings, i.e., the components added to the coating unit to form the coating around the particle components, include polyisocyanates and polyols. The polyisocyanates can have two or more isocyanate groups per molecule and can be aliphatic or aromatic. In one embodiment, the polyisocyanates are aromatic. In another embodiment, the polyisocyanates can be diisocyanates having exactly two isocyanate groups. Non-limiting examples of polyisocyanates suitable for use in forming the coating formulations of the present disclosure include methylene diphenyl diisocyanates (MDI), such as 4,4'-MDI, toluene diisocyanate (TDI), and combinations thereof. Examples of aromatic polyisocyanates are blends of polymeric isocyanates and isocyanate di-isomers.

[0045] The polyol may have at least two hydroxyl groups, two to five hydroxyl groups, or three to four hydroxyl groups per molecule. The polyol may be based on a polyether, polyester, or natural oil. In one embodiment, the polyol is based on a polyether. In some embodiments, the polyol has a hydroxyl number of 150 to 700 and an average functionality of 3. In this aspect, polypropylene or polyethylene polyols with a hydroxyl number of 150 to 700 and a functionality of 3 or 4 can be used because they provide a relatively short chain length (e.g., a molecular weight of 300 to 700 Da), which can contribute to the low viscosity of the polyol. In one embodiment, the polyol has a viscosity of less than 2000 mPa·s or less than 1000 mPa·s at 25°C, typically greater than 100 mPa·s at 25°C.

[0046] In another embodiment, the polyol is an aliphatic polyether polyol, such as a polyol formed from an initiator and multiple alkylene oxide units. The polyol may be initiated with a compound having three hydroxyl groups, such as glycerol, or an amine-initiated polyol, or a combination thereof. In yet another embodiment, the polyol is a polyethylene oxide, polypropylene oxide polyol, or other polyether polyol. Polyester polyols can also be used.

[0047] The polyol and polyisocyanate components can be selected to have a short cure time, i.e., less than about 5 minutes at 25°C, 70°C, and / or the temperature at which the coating is applied, thereby allowing subsequent application of coating layers, if applicable, at intervals of less than about 5 minutes. The amount and type of catalyst can be adjusted accordingly to accommodate such cure times. In one embodiment, the polyol and polyisocyanate components are selected to have a cure time of less than about 2 minutes at 25°C, 70°C, and / or the temperature at which the coating is applied.

[0048] In some embodiments, the coating is a polyester coating, more preferably a thermosetting polyester coating. In this aspect, the coating components can include an unsaturated polyester (containing a carbon-carbon double bond) and a vinyl monomer. The reaction of these components can include copolymerization of the vinyl monomer with the unsaturated polyester. The unsaturated polymer can be the reaction product of a saturated dicarboxylic acid (or anhydride), an unsaturated dicarboxylic acid (or anhydride), and a polyol, such as a diol (glycol). The glycol can be ethylene glycol, propylene glycol, 1,3-butylene glycol, hydrogenated bisphenol A, or a combination thereof. The glycol can be cyclic or acyclic, and can be aliphatic or aromatic. The glycol can have 2 to 30 carbon atoms. The vinyl monomer can be styrene. The reaction between the components can include copolymerization of the unsaturated polyester with the vinyl monomer in the presence of a free radical initiator and a catalyst. The unsaturated polyester can be injected as a liquid mixture with the vinyl monomer, which also acts as a solvent for the polyester.

[0049] In another embodiment, the coating is a polyurea coating and the coating components include a polyisocyanate and a polyamine. The polyisocyanate may be any of the polyisocyanates described above for the polyurethane coating, and the polyamine may have two or more amine groups per molecule, preferably 2 to 5 amine groups, and more preferably 3 to 4 amine groups.

[0050] In yet another embodiment, the coating is a hybrid polyurea-urethane or polyurethane-urea coating, and the coating components include a polyisocyanate, a polyamine, and a polyol, where the polyisocyanate, polyol, and polyamine can be any of those described above.

[0051] In yet another embodiment, the coating is a phenolic resin coating and the coating components include phenol and formaldehyde, the phenolic and formaldehyde components being capable of reacting in the coating unit to form a thermoset polymer.

[0052] In yet another embodiment, the coating is an epoxy coating, and the coating components include an epoxy component (having epoxide groups) and an optional co-reactant having reactive groups such as amines, acids and anhydrides, phenols, alcohols, and thiols. The co-reactant may have two or more reactive groups per molecule to result in the formation of a thermoset polymer. The epoxy component may crosslink by homopolymerization in a second step (described in more detail below) or by reaction with the optional co-reactant.

[0053] In some embodiments, the coating formulation may include initiators and / or catalysts, such as polymerization initiators (e.g., free radical initiators or cationic initiators) and polymerization catalysts (e.g., organometallic catalysts, tertiary amines, and organic or inorganic bases). The amount and type of catalyst can be adjusted depending on the desired cure time.

[0054] As discussed with respect to polyurethane coatings, the coating components of any suitable coating formulation described herein can be selected to have a cure time of less than about 5 minutes at 25° C., 70° C., and / or the temperature at which the coating is applied. When subsequent coating layers are applied (discussed in more detail below), the interval between coating layers can be about 5 minutes or less. In one embodiment, the coating components are selected to have a cure time of less than about 2 minutes at 25° C., 70° C., and / or the temperature at which the coating is applied.

[0055] The coating components may have a reactivity (time required for at least 50% hardening) of between about 10 and 300 seconds at room temperature. In one embodiment, the reactivity of the coating components is between about 10 and about 150 seconds. For example, the reactivity of the coating components at room temperature may be between about 10 and about 60 seconds. In another embodiment, the coating components have a reaction time of between about 30 and 250 seconds at 25°C (the reaction time is the time required for hardening). In another embodiment, the coating components have a reactivity of between about 10 and 60 seconds at the operating temperature of the coating unit and / or at 55°C. In yet another embodiment, the coating components have a reactivity of between about 10 and 120 seconds at the operating temperature of the coating unit and / or at about 55°C to about 70°C. In yet another embodiment, the coating components have a reactivity of between about 10 and 60 seconds at the operating temperature of the coating unit and / or at about 55°C to about 70°C. For example, the reactivity of the coating components at operating temperatures may be between about 10 and 45 seconds. As noted above with respect to the use of catalysts, reaction times can be achieved or adjusted by varying the amount and type of catalyst used in curing or hardening.

[0056] Additionally, the coating formulation may include wetting agents, surfactants, biocides, herbicides, insecticides, fungicides, antistatic agents, micronutrients, plant growth or health promoting additives, or combinations thereof. Non-limiting examples of micronutrients suitable for use in accordance with the present disclosure include Fe, Mn, Zn, Cu, Mo, Ni, Cl, Mg, and B.

[0057] The coating formulation may comprise less than about 5 wt. % water and / or organic solvent based on the total weight of the coating formulation. In this aspect, the organic solvent may comprise an organic compound having a boiling point less than 120° C. In some embodiments, the coating formulation comprises less than about 4 wt. % water and / or organic solvent based on the total weight of the coating formulation. In other embodiments, the coating formulation comprises less than about 3 wt. % water and / or organic solvent based on the total weight of the coating formulation. In still other embodiments, the coating formulation comprises less than about 1 wt. % water and / or organic solvent based on the total weight of the coating formulation. In still other embodiments, the coating formulation comprises less than about 5 wt. %, 4 wt. %, 3 wt. %, 2 wt. %, or 1 wt. % water and / or organic solvent based on the weight of the uncoated particle.

[0058] In some aspects, the coating formulation and / or one or more of the components therein, when applied to the underlayer particle, has a viscosity (measured according to ISO 3219:1993) of less than about 2000 mPa·s at 25°C. In one embodiment, the coating formulation and / or one or more of the components therein, when applied to the underlayer particle, has a viscosity of less than about 1000 mPa·s at 25°C. In another embodiment, the coating formulation or one or more of the components therein has a viscosity of about 100 mPa·s or greater at 25°C. In yet another embodiment, the coating formulation or one or more of the components therein has a viscosity of about 500 mPa·s or greater at 25°C.

[0059] While the coating formulation can include additives as described above, the coating formulation preferably includes less than about 40 wt. %, less than about 30 wt. %, less than about 20 wt. %, or less than about 10 wt. % (based on the total weight of the coating formulation) of components other than reactants necessary to carry out chemical reactions (described in more detail below). In this aspect, if the coating formulation includes a wetting agent, surfactant, or the like, such additives may be present in the coating formulation in an amount less than about 40 wt. % based on the total weight of the coating formulation.

[0060] As briefly discussed above, the coating may be water-impermeable. In some embodiments, when the underlying particle is a seed, the coating protects the seed therein from the environment until weather conditions are sufficient to initiate seed germination, at which point the coating ruptures and root and plant growth begins. In other embodiments, the coating is semi-permeable (e.g., permeable to water and / or other solutes). When water penetrates the coating by osmosis, seed germination / swelling can occur, leading to cracking or rupture of the coating. In this aspect, sustained and / or delayed rupture of the coating material can be achieved. Indeed, unlike when the underlying particle is a fertilizer (where water penetrates the coating film, causing the fertilizer to go into solution and be forced out of the pores of the coating), the coating of the finished coated seed produced according to the present disclosure ruptures once germination occurs as the underlying seed ruptures and root formation begins. Thus, unless the coated seeds are subjected to climatic factors that dictate the growing season, it is contemplated that coated seeds produced according to the present disclosure will have not only an improved shelf life but also a germination rate similar to or, in some cases, better than uncoated seeds. Furthermore, while uncoated seeds may have to be buried after the initial growing season because the germination rate in the second growing season may be significantly lower than the initial germination rate, i.e., about 90% or less, the coated seeds of the present disclosure not only have an initial germination rate that is equal to or better than uncoated seeds, but also have a) a second growing season germination rate within about ±5% of the initial germination rate, and b) a shell that decomposes after its useful life.

[0061] In some embodiments, the coating itself contains plant nutrients to aid in plant development. In other embodiments, the coating includes a growth stimulating additive, a stress reducing additive, or a combination thereof to help reduce stress in the plant. In yet other embodiments, the coating includes plant nutrients and a growth stimulating additive or a stress reducing additive.

[0062] When the sub-layer particles are fertilizers, the thickness of the coating (after being applied to the sub-layer particles) is from about 1.0 μm to about 150 μm, 10 μm to about 100 μm, 20 μm to about 75 μm, or 30 μm to about 50 μm for the entire coating layer and / or for each coating layer, although other thicknesses are possible.

[0063] When the sublayer particle is a seed, the coating thickness (after being applied to the sublayer particle) is from about 1.0 μm to about 50 μm for the entire coating layer and / or for each coating layer, although other thicknesses are possible. In one embodiment, the coating thickness is from about 5 μm to about 45 μm. In another embodiment, the coating thickness is from about 10 μm to about 35 μm. In this aspect, the coating may include one or more layers, each formed from a coating formulation described herein, which may be the same or different for each coating layer.

[0064] The coating may be at least about 0.0010 wt% based on the total coated particle weight, across all coating layers and / or per coating layer. In some aspects, the coating is about 0.10 wt% to about 20 wt% based on the total coated particle weight. In other aspects, the coating is about 0.2 wt% to about 15 wt% based on the total coated particle weight. In still other aspects, the coating is about 0.3 wt% to about 10 wt% based on the total coated particle weight. In still other aspects, the coating is about 1 wt% to about 8 wt% based on the total coated particle weight. In still other aspects, the coating is about 0.2 wt% to about 5 wt% based on the total coated particle weight. In some embodiments, the coating is about 0.3 wt% to about 3 wt% based on the total coated particle weight. In other embodiments, the coating is about 0.5 wt% to about 1.5 wt% based on the total coated particle weight.

[0065] In this embodiment, the particles may have an initial coating of about 0.5 to about 5 weight percent, based on the total coated particle weight, solely for storage purposes, blend compatibility, or a combination thereof. For example, this weight of coating may be useful to enhance the stability of uncoated seeds, allowing the coated seeds to be planted in a second growing season (rather than in the first or earlier growing season) with the same or substantially the same germination rate as if planted in the first growing season. In this regard, coated seeds may also be subsequently subjected to an additional coating step to add to the coating weight to improve or maintain germination rates when planted outside of the normal growing season. For example, 1 to 2 weight percent of the coated seeds (based on the total coated seed weight) may be recoated to add further protection or isolation from extreme weather conditions, pest insects, and / or moisture. In this manner, the coated particles may be (i) subjected to a first coating step at a first time to provide a first coating or layer having a first weight, and (ii) subjected to a second coating step at a second time to provide a second coating or layer having a second weight.

[0066] Preparation method of carrier powder As briefly discussed above, a predetermined amount of microbial consortium-containing carrier powder is added to the product in vegetative or spore form before, during, or after the polymer coating layer is in place. The carrier powder, microbial consortium, and methods of making the microbial consortium-containing carrier powder are discussed in this section.

[0067] Carrier powders may include, but are not limited to, agar, bone meal, calcium carbonate, calcium oxide, calcium hydroxide, calcium phosphate, calcium silicate, calcium stearate, carbon black, cocoa shell powder, dextrose, diatomaceous earth, dolomite, fuller's earth, kaolin clay, ammonium magnesium phosphate, magnesium oxide, magnesium silicate, magnesium stearate, montmorillonite, perlite, phosphate rock, potassium alginate, poultry ash, rice husk ash, sawdust, silica, sodium alginate, sucrose, talc, vermiculite, zinc oxide, zinc stearate, zeolite, and combinations thereof. The average particle size of the carrier powder may range from about 0.1 to about 150 μm. In one embodiment, the average particle size of the carrier powder may range from about 0.5 to about 100 μm. In another embodiment, the average particle size of the carrier powder may range from about 1 to about 50 μm.

[0068] The microbial consortium includes polymer coating-degrading microorganisms. Generally, a microbial consortium or co-culture is a combination of various microorganisms that can degrade certain types of polymeric materials with greater biodegradation ability compared to the application of individual isolates under ideal environmental conditions. For example, without being bound by any particular theory, some microorganisms can effectively degrade various types of plastic polymers at a faster rate in the form of a consortium / co-culture compared to their application as pure cultures.

[0069] In some embodiments, the consortium may include one or more of the following bacterial decomposition microorganisms: Acinetobacter calcoaceticus, Acinetobacter germeri P7, Alicyclifilus sp. BQ1, Alicyclifilus sp. BQ8, Arthrobacter sp., Arthrobacter calcoaceticus ATCC31012, Arthrobacter calcoaceticus NAV-2, Arthrobacter globiformis, Bacillus sp., Bacillus pumilus NMSN-1d, Bacillus subtilis subtilis, Chryseobacterium meningosepticum, Comamonas acidovorans TB-35, Corynebacterium sp., Delftia acidovorans TB-35, Enterobacter agglomerans, Micrococcus sp., Pseudomonas sp.), Pseudomonas aeruginosa, Pseudomonas aeruginosa, Pseudomonas aeruginosa, Pseudomonas aeruginosa ATCC13388, Pseudomonas aeruginosa ATCC9027, Pseudomonas aeruginosa MTCC7814, Pseudomonas aeruginosa MZA-85, Pseudomonas aeruginosa NAV-6, Pseudomonas cepacian, Pseudomonas chlororaphis, Pseudomonas Pseudomonas chlororaphis ATCC 55729, Pseudomonas fluorescens, Pseudomonas proegens Pf-5, Pseudomonas putida, Pseudomonas putida ATCC 17484, and Serratia rubidaea. Without being bound by any particular theory, these bacterial degradation microorganisms degrade polyester polyurethanes through enzymatic hydrolysis.

[0070] In some embodiments, the consortium may include one or more of the following bacterial decomposition microorganisms: Rhodococcus equi TB-60, Staphylococcus epidermidis, Exophiala jeanselmei REN-11A, Bacillus amyloliquefaciens, Comamonas acidovorans TB-35, Escherichia coli, Micrococcus sp., Pseudomonas fluorescens, Pseudomonas protegens Pf-5, Staphylococcus aureus, Staphylococcus epidermidis epidermidis and Staphylococcus epidermidis strain KH11. Without being bound by any particular theory, such bacterial degradation microorganisms degrade polyether polyurethanes via enzymatic hydrolysis.

[0071] In still other embodiments, the consortium may include one or more of the following fungal decomposition microorganisms: Alternaria sp., Alternaria Solani Ss.1-3, Alternaria PURDK2 strain, Alternaria tenuissima, Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Aspergillus niger ATCC9642, Aspergillus section flavi, Aspergillus terreus, Aspergillus tubingensis, Aspergillus versicolor versicolor, Aureobasidium pullulans, Bionectria sp. E2910B, Chaetomium globosum, Cladosporium sp., Cladosporium asperulatum, Cladosporium ontecillanum, Cladosporium pseudocladosporioides, Cladosporium tenuissimum, Cryptococcus laurentii, Curvularia senegalensis, Fusarium solani), Gliocladium roseum, Lasiodiplodia sp.) E2611A, Penicillium chrysogenum, Penicillium funiculosum, Penicillium section lanata-divaricata, Pestalotiopsis microspore E33 / 7A, Pestalotiopsis microspore E27 / 2A, Pleosporales sp. E28 / 2A, or Trichoderma sp. Without being bound by any particular theory, such fungal degrading microorganisms degrade polyester polyurethanes via enzymatic hydrolysis.

[0072] In still other embodiments, the consortium may include one or more of the following fungal decomposition microorganisms: Alternaria sp. strain PURDK2, Alternaria tenuissima, Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Aspergillus versicolor, Aureobasidium pullulans, Chaetomium globosum, Cladosporium sp., Cladosporium tenuissimum, Cladosporium asperulatum, Cladosporium herbalum Herbarum, Cladosporium montecillanum, Cladosporium pseudocladosporioides, Exophiala jeanselmei REN-11A, Penicillium chrysogenum, Penicillium funiculosum, and Trichoderma sp. Without being bound by any particular theory, such fungal degrading microorganisms degrade polyether polyurethanes via enzymatic hydrolysis.

[0073] In still other embodiments, the consortium may include one or more of the following enzymes: Basillus sp. protease, Bacillus subtilis esterase, bromelain, Candida antarctica lipase, Candida cylindracea lipase, cathepsin C, cholesterol esterase, chymotrypsin, collagenase, Comamonas acidovorans TB-35 esterase, Curvularia senegalensis esterase, and / or erythrocyte membrane enzymes. senegalensis esterase, esterase, ficin, fungal peroxidase, human neutrophil elastase, laccase, leucine aminopeptidase, lipase, lipase AK, lipase PS, Lipolase 100L, Novozym 51,032, Novozym 735, Palatase 20,000, papain, porcine liver esterase, protease K, Pseudomonas cepacia lipase, Pseudomonas fluorescens esterase, Pseudomonas lipase, PueA (Pseudomonas chloroaphis lipase), PueB (Pseudomonas chloroaphis lipase), Rhizopus arrhizus lipase, Rhizopus delemar lipase, Tcur0390 (Thermomonospora curvata DSM 43183 hydrolase), Tcur1278 (Thermomonospora curvata DSM 43186 hydrolase), Thermomyces lanuginosus lipase, and urease. Without being bound by any particular theory, such enzymes degrade polyester-based polyurethanes via enzymatic hydrolysis.

[0074] In other embodiments, the consortium may include one or more of the following enzymes: lipase AK, Pseudomonas cepacia lipase, Thermomyces lanuginosus lipase, esterase, porcine pancreatic lipase, cholesterol esterase, leucine aminopeptidase, cathepsin C, chymotrypsin, porcine pancreatic elastase, papain, ficin, human neutrophil elastase, collagenase, and urease. Without being bound by any particular theory, such enzymes degrade polyether-based polyurethanes via enzymatic hydrolysis.

[0075] In one embodiment, the consortium includes two or more microorganisms classified as Biosafety Level 1 (BSL-1) organisms. As will be understood by those skilled in the art, BSL-1 has specific controls for containment of microorganisms and biological agents, determined by, among other things, infectivity, disease severity, transmissibility, and the nature of the work being performed. In this aspect, microorganisms classified as BSL-1 organisms are not known to consistently cause illness in healthy adults and pose minimal potential risk to laboratory workers and the environment. Non-limiting examples of microorganisms classified as BSL-1 organisms include Escherichia coli, Pseudomonas fluorescens, Staphylococcus epidermidis, and Aspergillus niger. In another embodiment, the consortium includes two or more microorganisms classified as BSL-1 organisms capable of degrading ether-based polyurethanes, ester-based polyurethanes, and combinations thereof via enzymatic hydrolysis.

[0076] In some instances, two or more species are in physical contact with each other. In some embodiments, microorganisms within a consortium can affect each other through direct physical contact, biochemical interactions, or both. For example, microorganisms within a consortium can exchange nutrients, metabolites, or gases with each other. In this embodiment, at least some of the microorganisms within a consortium can be metabolically interdependent.

[0077] In this aspect, various specially selected microorganisms can be combined to form the microbial consortium of the present disclosure, where the microorganisms are compatible, coexist, and actively grow together to biodegrade the residual coating shell of the coated particles. The microbial consortium does not pose a health risk to humans, animals, plants, or the environment. In some embodiments, the microbial consortium includes a first set of microorganisms selected to biodegrade the residual coating shell and a second set of microorganisms selected to biodegrade the wax-based sealant. For example, the microbial consortium can include a first set of bacterial degradation microorganisms capable of degrading the polymer coating and a second set of microorganisms capable of degrading the wax-based sealant. In some embodiments, the microbial consortium can include a first set of microorganisms including at least two of Escherichia coli, Pseudomonas fluorescens, Staphylococcus epidermidis, and Aspergillus niger, and a second set of microorganisms capable of degrading a wax-based sealant.

[0078] Microorganisms use polymers and wax compounds as an energy source for their growth by secreting extracellular enzymes. The polymers are then depolymerized (and biodegraded) by these enzymes. In other words, the biodegradation of the residual coating shell generally involves three steps: (a) microbial attachment to the surface of the polymer, (b) utilization of the specific polymer as an energy source, and (c) polymer degradation. Without being bound by any particular theory, the fact that these microorganisms do not have to compete to survive but rather coexist to convert the polymers in the residual coating shell into carbon dioxide, water, and organic matter is essential to the biodegradation process of the present disclosure.

[0079] In some embodiments, the microbial consortium is contained in a liquid medium (e.g., a storage medium, a culture medium, or a fermentation medium), e.g., as a suspension in the liquid medium. In this aspect, the concentration of each species in the microbial consortium is about 1.0 x 10 5 CFU / gram ~ approx. 1 x 10 10 CFU / gram range. In other embodiments, the microbial consortium is contained on the surface of or embedded within a solid or gelatinous medium (including but not limited to a culture plate), or a slurry or paste.

[0080] There are several process techniques available for impregnating the microbial consortium solution onto the carrier powder. The concentration of the microbial consortium (i.e., the total number of microorganisms in the carrier powder) is approximately 1.0 x 10 11 CFU / gram ~ approx. 1.0 x 10 15The CFU / gram range can be used. The ratio (%) of carrier powder to microbial consortium can be in the range of 90:10 to 99:1. For example, in some embodiments, the microorganism-containing carrier comprises about 90 to about 99.9% carrier powder and about 0.1 to about 10% microbial consortium. In one aspect, the microorganism-containing carrier comprises about 95 to about 98% carrier powder and about 5 to about 2% microbial consortium. In another aspect, the microorganism-containing carrier comprises about 99 to about 99.5% carrier powder and about 1 to about 0.5% microbial consortium. In yet another aspect, the microorganism-containing carrier comprises about 90 to about 95% carrier powder and about 10 to about 5% microbial consortium. In yet another aspect, the microorganism-containing carrier comprises about 95 to about 99.5% carrier powder and about 5 to about 0.1% microbial consortium.

[0081] In some embodiments, the production of fully functional dried microorganism-containing carriers depends on the process used to remove water. Additionally, because microorganisms are heat-sensitive, the temperature range can be approximately 0°C to 60°C (to minimize damage to microorganisms in the vegetative state). As will be understood by those skilled in the art, the temperature limit / range for microorganisms in spore form is species-dependent. In fact, for microorganisms treated in the dormant spore form, the temperature limit can have a much wider range. Generally, spores can tolerate temperatures approximately 40-45°C higher than the corresponding vegetative state, and the heat resistance of spores can be up to 10°C. 5 will rise to twice as much.

[0082] Once the microbial consortium solution has been applied, the carrier powder can be dried using one or more drying techniques, such as a filtration process, a decantation process, ambient air drying, low heat and high airflow exposure, centrifugation, vacuum drying, and / or freeze drying, to dry the microbial consortium-containing carrier powder prior to use.

[0083] In one embodiment, a fluidized bed drying process is used to produce a microbial consortium-containing carrier powder. In this aspect, the fluidized bed system can include a blower and fluidization gas filtration system, a fluidization gas heater, a lower plenum, a fluidization chamber equipped with a gas distribution plate and liquid spray nozzles, an expansion chamber, an upper plenum equipped with filtration, and an exhaust blower. Air or an alternative gas stream can be filtered and preheated and introduced into the lower plenum of the fluidized bed. A gas distribution plate located at the base of the fluidization chamber distributes the air evenly through the bed of carrier particles. Generally, once the particles are suspended in the gas stream, a liquid is pumped to a spray nozzle using a fluid metering system. The spray nozzle atomizes the liquid into small droplets. The small droplets contact the fluidized particles and are absorbed or collected on the surface of the fluidized carrier powder. The suspended particles containing the liquid continue to fluidize until evaporation occurs. The fluidization gas and water vapor pass through the expansion chamber, the filtration system, and exit the fluidized bed through the exhaust blower. At the completion of this cycle, the dry carrier particles containing the microorganisms are discharged from the fluidized bed and stored or packaged for future use.

[0084] The operating conditions of a fluidized bed are generally dictated by the characteristics of the fluidized solid that serves as the carrier. The particle size, bulk density, and fluidization rate of the carrier powder are some of the characteristics that influence the design and operation of the fluidized bed. Other process considerations include the amount of water that must be evaporated when the microbial consortium solution is applied to the carrier powder. The fluidization air temperature and gas velocity are two important factors that determine the drying rate.

[0085] In some embodiments, the process involves a bed of carrier powder particles suspended in a controlled amount of preheated fluidizing gas directed through a perforated gas distribution plate. As the powder and fluidizing gas mix uniformly, the carrier powder particles become buoyant in the gas stream, the bed volume expands significantly, and the carrier powder particles behave like a liquid. Once the carrier powder particles reach steady-state fluidization in the heated gas stream, a microbial consortium solution is sprayed onto the fluidized bed of carrier powder particles. The spray droplets of the microbial consortium solution remain liquid when applied to the surfaces of the fluidized carrier powder particles. The microorganisms are absorbed into the interior and surfaces of the fluidized carrier powder particles. As the particles continue to fluidize in the heated gas stream, evaporation of the liquid occurs, and the dry carrier powder now contains polymer-degrading microorganisms.

[0086] Method for producing coated particles In the first step of the method, particles are fed into a coating unit. In some embodiments, the coating unit is a high-speed mixer / coater including a rotating pan and a rotor, and the speed of the rotating pan and the speed and direction of the rotor can be independently controlled. Suitable mixer / coaters are available, for example, from Eirich. Such coating units facilitate rapid particle mixing and promote particle-to-particle surface contact, allowing for uniform coating of the coating formulation. Furthermore, high-speed agitation can allow for the addition of several layers of coating applied in a short period of time. The mixer / coater can be operated in batch or batch-continuous mode using multiple units.

[0087] In some embodiments, particles may be sieved to a desired particle size before being introduced into the coating unit. In other embodiments, particles may be preheated before being fed into the coating unit. In this aspect, the particles may be preheated to a temperature of at least about 30°C, at least about 40°C, at least about 50°C, at least about 60°C, or at least about 70°C. In other aspects, the particles may be preheated to a temperature of about 5°C to about 50°C above ambient temperature before being fed into the coating unit. For example, the particles may be preheated to a temperature of about 15°C to about 40°C. In one embodiment, the particles are preheated to a temperature of about 20°C to about 30°C. In yet another aspect, the particles may be preheated to a temperature of about 15°C to about 60°C. In one embodiment, the particles are preheated to a temperature of about 20°C to about 80°C.

[0088] The particles may be supplied to the coating unit in an amount greater than about 10%, greater than about 20%, greater than about 40%, or greater than about 60% of the volume of the interior space of the coating unit (based on the bulk density of the seed components), and / or less than about 95%, less than about 90%, or less than about 80%. In one embodiment, the particles are supplied to the coating unit in an amount of about 60% to about 90% of the volume of the interior space of the coating unit. In another embodiment, the particles are supplied to the coating unit in an amount of about 75% to about 90% of the volume of the interior space of the coating unit. A volume fraction based on bulk density means that the bulk of the bed of uncoated particles (including the void space in the bed) occupies the volume fraction of the interior space. Without being bound by any particular theory, a packing fraction in this range may contribute to the formation of a floating bed and good distribution of the coating components.

[0089] Once the particles are loaded into the coating unit, the coating formulation component(s) are added to the coating unit in the second step of the method and allowed to react within the coating unit. This second step can be carried out (and completed) in about 10 to about 600 seconds. In one embodiment, the second step is carried out in about 30 to about 240 seconds. For example, the second step can be carried out in about 30 to about 120 seconds or about 30 to about 90 seconds. In another embodiment, the second step is carried out in about 10 to about 120 seconds. For example, the second step can be carried out in about 10 to about 60 seconds or about 10 to about 30 seconds. In some embodiments, the coating component(s) are added to the coating unit, more specifically, to one of the moving elements, in about 0.5 to about 30 seconds, about 1 to about 10 seconds, or about 1 to about 5 seconds. In other embodiments, the coating component(s) are dispensed onto (ie, mixed with) the particles for about 5 to about 45 seconds, or about 10 to about 30 seconds.

[0090] Although this second step of the method involves applying one coating layer, the step of applying a coating layer can be performed more than once to provide coated particles with one or more coating layers. Additionally, other compounds and layers, such as solvent and wax layers, can be applied simultaneously or subsequently to the coating application step, as needed. For example, at least two coating layers (having the same or different coating formulations) can be applied in stages. When this second step is performed more than once to provide two or more coating layers on the coated particles, these times refer to instances of the second step. In one embodiment, step b) includes sequentially and incrementally applying two or more coating components to the seed particles while both the container and the rotor are rotating. In another embodiment, the coating component that is first added to the particles has a higher molecular weight (e.g., number average molecular weight) and / or a higher viscosity than the second coating component. In yet another embodiment, the first coating component is added to the particles and mixed for 2 to 120 seconds, e.g., 10 to 60 seconds, and then the second coating component is added. The mixing of the first coating component can result in a uniform distribution of the coating component on the particles at the end of the mixing period and before the second coating component is added. In some aspects, both coating components are injected as liquids, preferably into the bed of levitating particles (which can include dripping and spraying). In one embodiment, the bed of levitating particles includes a zone where the particles are moving fastest (e.g., near the rotor), and the coating component is added to that area. This allows for a rapid uniform distribution of the coating component on the particles.

[0091] In some embodiments, the first two coating components added are reactive with each other. After one or more reactive coating components are applied, the method may include allowing the coating components to react with each other while maintaining the particles in motion, for example, for a period of 10 to 300 seconds, e.g., 10 to 120 seconds. An advantage of the coating method of the present disclosure is that the reaction carried out in the coating unit can provide hardening or hardening of the particles without causing weak agglomeration of the coated particles. Another advantage of the coating method of the present disclosure is that the reaction carried out in the coating unit can provide hardening or hardening of the particles at a lower temperature than other similar techniques, ensuring the survival of added polymer-degrading microorganisms.

[0092] The coating formulation(s) can be applied as a liquid. In this aspect, the liquid can be in the form of an emulsion, solution, or dispersion. In other embodiments, the coating formulation can be applied as a polymer melt at a temperature sufficiently above the glass transition temperature of the polymer, for example, so that the polymer has a sufficiently low viscosity.

[0093] The first and second steps of the method can be carried out at a temperature ranging from about 10°C to about 120°C. In one embodiment, the first and second steps of the method are carried out at a temperature of at least about 10°C, at least about 30°C, at least about 40°C, at least about 50°C, at least about 55°C, at least about 60°C, or at least about 70°C. In another embodiment, the first and second steps of the method are carried out at a temperature of less than about 120°C or less than about 80°C. For example, the first and second steps of the method can be carried out at a temperature range of about 40°C to about 120°C, about 50°C to about 100°C, or about 55°C to about 75°C.

[0094] The third step of the method also includes at least partially curing or hardening one or more coating layers. The curing or hardening step involves a chemical reaction of one or more components in the coating formulation while in the coating unit. The coating particles remain in motion during curing. The chemical reaction may result in polymerization and / or crosslinking of a polymer, an increase in the viscosity of the coating layer, or both. In this regard, the chemical reaction may include crosslinking to form a thermosetting polymer, or may not include crosslinking to form a thermoplastic polymer. Furthermore, when the coating formulation is formed from only one reactant / component, the component may react with itself, for example, in a polymerization reaction. As previously mentioned, initiators and / or catalysts may be used to effect the hardening or hardening. In one embodiment, the third step is carried out (and completed) in about 60 seconds to about 10 minutes. For example, the third step may be carried out in about 2 to about 8 minutes. In another embodiment, the third step is carried out in about 1 to about 6 minutes.

[0095] Depending on the degree of curing, further curing or hardening can be performed after the third step, i.e., in the fourth step, before and / or after the discharge of the coated particles from the coating unit. An optional final curing or hardening step is applied to bring the coated particles into a state suitable for discharge, e.g., non-tacky and with sufficient mechanical / crushing strength for handling, packaging, and storage. The final hardening step may include evaporation of unreacted monomers or cooling and / or a final hardening chemical reaction step. The final hardening step may include further reaction of the coating components present in the applied coating layer (with or without an initiator or catalyst). In this aspect, the final hardening step may include crosslinking of the polymeric coating material. In one embodiment, the final hardening or hardening step is performed in the same or a different coating unit as used for the second and / or third steps of the method.

[0096] In one embodiment, the fourth step is carried out (and completed) in about 1 minute to about 15 minutes. For example, the fourth step may be carried out in about 2 to about 12 minutes. In another embodiment, the fourth step is carried out in about 1 minute to about 8 minutes. In yet another embodiment, the fourth step is carried out in about 2 to about 5 minutes.

[0097] The residence time in the coating unit can be about 30 minutes or less. In one embodiment, the residence time is about 20 minutes or less. In a second embodiment, the residence time is about 15 minutes or less. In another embodiment, the residence time is about 10 minutes or less. In yet another embodiment, the residence time is about 5 minutes or less.

[0098] As mentioned above, if additional ingredients are used, such as wetting agents, surfactants, etc., such ingredients can be added to the coating unit in the second step along with the other ingredients in the coating formulation, or in the third step, i.e., the curing or hardening step.

[0099] The coating can include a wax, which can be applied as a layer between the coating layers that are cured or hardened during the third step and / or as a final layer. The wax can be an olefin-based wax. In one embodiment, the wax is an alpha-olefin-based wax having at least 20 carbon atoms. In another embodiment, the wax is an alpha-olefin-based wax having at least 30 carbon atoms. In this aspect, the wax can be a hydrocarbon (such as an alkane) having 20 to 40 carbon atoms. The wax can also be paraffin wax, petrolatum wax, polyamide wax, or a combination thereof. In one embodiment, the wax is a microcrystalline wax. Thus, suitable waxes can include, but are not limited to, Evacote®, Alpha Olefin® C30+, Alpha Olefin® C30+HA, Neodene 26+ Alpha Olefin Wax, Neodene 2024 Alpha C20-22 Linear Olefin, polyethylene / bright stock oil mixtures, animal fat-based waxes, and hydrogenated oils, and similar materials, all from The International Group, Inc.

[0100] The microorganism-containing carrier can be applied to the particles while they are in the coating unit. In this regard, the carrier powder can be applied before, after, or during coating with the polymer or wax layer. In fact, the carrier powder can be added during the polymer or wax coating, or can be combined with the wax or polymer layer coating material, for example, by mixing or premixing it with the polyol or isocyanate material. For clarity, if the carrier powder is added during the polymer or wax coating, it may adhere to those layers, and therefore the carrier powder is not necessarily considered or always shown as a separate layer herein. Thus, the coating step can include adding the microbial consortium-containing carrier powder before, during, or after application of at least one coating of polyol or isocyanate.

[0101] The method also includes discharging the coated particles from the coating unit. In one embodiment, the coated particles are at least about 70°C when discharged from the coating unit. After discharge, the coated particles may be subjected to additional steps, including, but not limited to, a cooling step, a packaging step, a weighing step, a storage step, or a combination thereof. For example, the coated particles may be cooled from the exit temperature (e.g., about 70°C or higher) to about 30°C or lower. In this aspect, the cooling step may include suspending the coated particles in cooled air. The packaging step may include packaging the coated particles in bags or containers. The weighing step may include dividing the stream of coated particles into metered batches so that the batches can be transferred to a desired mode of transportation (with or without packaging).

[0102] The coating methods described herein can be carried out as a batch or continuous process. For example, a batch process can be used to produce coated particles having multiple coating layers, i.e., two or more steps of applying coating layers are performed in the same coating unit. Furthermore, in a batch process, one or more components of the coating formulation can be added sequentially over a period of about 10 seconds or more. Two or more batch coating units can operate in parallel, with the parallel coating units performing different steps simultaneously. In such embodiments, the disclosed methods can be carried out in a batch continuous mode or a semi-continuous mode. In this aspect, the method can include loading particles into a first coating unit and applying coating layer(s) and carrier powder while a second coating unit performs a different step. In such embodiments, the method can include applying all of the coating layers (e.g., one, two, three, or more layers) and carrier powder to be applied to the particles in one of the parallel coating units.

[0103] In one embodiment, the method is carried out as a continuous process, in which two or more coating layers are applied in different coating units arranged in series, and the partially coated particles are transported from the first coating unit after application of the first coating layer to a second coating unit for application of a carrier powder and a second series of coating layers. Transport may be achieved by a moving belt, or the coating units may be arranged one on top of another so that transport is carried out by gravity. A continuous process may include continuous feeding of particles to the first coating unit and transport of the partially coated particles (i.e., transporting particles with a coating layer from the first coating unit to a downstream second coating unit, and recovering partially coated particles with an additional coating layer from the second coating unit). In another embodiment, two or more coating units as described are used in series, with different coating layers applied in stages in the different coating units, and transporting includes transporting batches of coated particles from at least the first coating unit to a downstream second coating unit.

[0104] In such embodiments, the coating unit can include multiple coating devices arranged in series or in parallel, each including a container and at least one rotor. For example, the coating unit can include multiple coating devices arranged in series and connected to each other by a transport line (such as a moving belt or duct) for coating or partially coating particles, each coating device having one container. Each container, for example, has an inlet and an outlet for the coating particles. In another embodiment, a coating system is used using multiple coating units in parallel and with a common cooling stage downstream of the coating units.

[0105] In a non-limiting example, the coating unit includes a container and a rotor as two moving elements, the coating is a polyurethane coating, and the second step includes the following in succession (after each other, but optionally with further steps before, between, and / or after): and the addition of a carrier powder. 1) The polyol is injected into a bed of particles in a vessel, and the granules in the bed are suspended by the movement of the vessel and the rotor; injection may be carried out using an open tube or a spray nozzle; 2) mixing the polyol with the particles for about 5 to about 120 seconds, preferably about 10 to about 60 seconds; 3) Injecting the polyisocyanate component into the bed of particles in the container, which may be done using an open tube or a spray nozzle; 4) rolling the particles in the container for at least about 10 to about 300 seconds, preferably about 20 to about 180 seconds, to react the polyol and polyisocyanate components with each other and at least partially cure the coating layer; 5) using an open tube to inject molten wax sealant into the bed of coating particles; 6) Weighing out a predetermined amount of carrier powder; and 7) Repeat process steps 1-5.

[0106] In one embodiment, the steps of injecting the coating components may be reversed, i.e., the step of injecting the polyisocyanate component may occur before the step of injecting and mixing the polyol. Of course, other coating components may be used in place of the polyol and / or polyisocyanate to provide a coating formed from any of the other suitable coatings described above. In the rotating step, the coating unit and its movable elements may be rotated or otherwise manipulated to effect rotation of the particles.

[0107] Because the microbial consortium-containing carrier powder is applied to each coated particle, the microorganisms are both protected by the coating shell and slowly released onto the plastic surface, degrading the coating shell. In fact, the disclosed method ensures that the microorganisms within the microbial consortium continue to grow and replenish until all of the polymer is degraded. In fact, the process of polymer degradation does not occur until environmental conditions are consistent with promoting microbial activity and proliferation. Furthermore, because the microbial consortium-containing carrier powder is applied to each coated particle, biodegradation of the polymer coating shell does not depend on the specific type or concentration of microorganisms present in the environment (soil or water).

[0108] Thus, each coated particle contains a predetermined concentration of microorganisms sufficient to substantially biodegrade the polymer coating within a certain period of time. In some aspects, "substantially biodegrade" means that less than about 10% of the residual coating shell remains after a target period of time (as that term is defined below to begin after the end of the functional period of the coated particle). In other words, more than about 90% of the organic carbon in the polymer coating is converted to carbon dioxide during the target period of time. In some embodiments, less than about 5% of the residual coating shell remains after the target period of time, and / or more than about 95% of the organic carbon in the polymer coating is converted to carbon dioxide during the target period of time. In other embodiments, less than about 3% of the residual coating shell remains after the target period of time, and / or more than about 97% of the organic carbon in the polymer coating is converted to carbon dioxide during the target period of time. In still other embodiments, less than about 1% of the residual coating shell remains after the target period of time, and / or more than about 99% of the organic carbon in the polymer coating is converted to carbon dioxide during the target period of time. In yet other embodiments, less than about 0.1% of the residual coating shell remains after the target period, and / or greater than about 99.1% of the organic carbon in the polymer coating is converted to carbon dioxide during the target period, in which case the polymer coating ultimately decomposes into carbon dioxide, biomass, and water.

[0109] In some embodiments, the target period is about 48 months or less after the end of the functional period of the coated particle. For example, if the functional period of the coated particle, i.e., the length of time required for the coated particle to release its intended nutrients, is about 12 months, the total period until the coated particle is substantially biodegraded is about 60 months. In other embodiments, the target period is about 36 months or less after the end of the functional period of the coated particle. In yet other embodiments, the target period is about 24 months or less after the end of the functional period of the coated particle. In yet other embodiments, the target period is about 16 months or less after the end of the functional period of the coated particle. In other embodiments, the target period is about 12 months or less after the end of the functional period of the coated particle.

[0110] In this aspect, the target duration can range from about 1 month to about 48 months. In some embodiments, the target duration ranges from about 3 months to about 42 months. In other embodiments, the target duration ranges from about 6 months to about 36 months. In yet other embodiments, the target duration ranges from about 9 months to about 30 months. In yet other embodiments, the target duration ranges from about 12 months to about 24 months.

[0111] The microbial consortium-containing carrier powder may be present in the coated particles in an amount of about 0.01 to about 10 wt % based on the total weight of the coated particles. In some embodiments, the microorganism-containing carrier is present in an amount of about 0.05 to about 5.0 wt % based on the total weight of the coated particles. In other embodiments, the microorganism-containing carrier is present in an amount of about 0.1 to about 5.0 wt % based on the total weight of the coated particles. In still other embodiments, the microorganism-containing carrier is present in an amount of about 0.5 to about 1.5 wt % based on the total weight of the coated particles. In still other embodiments, the microorganism-containing carrier is present in an amount of about 0.1 to about 1.0 wt % based on the total weight of the coated particles. In other aspects, the amount of the microorganism-containing carrier that can be added ranges from about 0.2% to about 1.0% based on the total weight of the coated particles. In still other aspects, the amount of the microorganism-containing carrier that can be added ranges from about 0.25% to about 0.75% (based on the total weight of the coated particles).

[0112] In some embodiments, the amount of microorganism-containing carriers can be determined based on the weight percentage and / or thickness of the polymer coating, the desired degradation time, and combinations thereof. For example, coated particles having a coating thickness of about 5 μm to about 15 μm can contain fewer microorganism-containing carriers than coated particles having a coating thickness of about 20 μm to about 40 μm. Similarly, coated particles having a coating weight of about 4% can contain a higher concentration of microorganism-containing carriers than coated particles having a coating weight of about 2 to 2.25% (based on the total weight of the coated particles). For example, coated particles having a coating weight of about 4% can contain about 0.5 to about 0.75% microorganism-containing carriers compared to about 0.15 to about 0.35% for coated particles having a coating weight of about 2.25% (based on the total weight of the coated particles).

[0113] In other embodiments, a solution containing a microbial consortium can be sprayed / applied onto the underlying particles or one or more coating layers. More specifically, in contrast to the microbially impregnated carrier powder described above, the microbial consortium solution remains liquid for application. For example, such application can be particularly useful when a thin coating is applied for storage or compatibility purposes.

[0114] The coating method of the present disclosure offers several advantages over the prior art, including, but not limited to, avoidance of damage to underlying particles and microorganisms or spores, faster reaction times, and the absence of particle agglomeration.

[0115] Finished coating particles As shown in FIG. 1, the finished coated particle 10 includes at least a base particle 12 and a protective coating layer 14 that includes multiple layers. In this embodiment, the protective coating layer 14 can include one or more layers of cured and hardened polyol, polyisocyanate, and wax. The coating layer 14 can also include a carrier powder between the one or more layers of cured and hardened polyol. In some embodiments, the coating layer 14 is applied in a second step in an amount of about 0.10 to about 20 wt %, about 0.2 to about 15 wt %, about 0.3 to about 10 wt %, or about 0.5 to about 5 wt %, based on the weight of the particle. When the second step, i.e., the coating step, is performed two or more times, these amounts refer to one example of the second step. For example, if four coating layers are present, each individual coating level can be about 0.025 to about 5 wt %, about 0.05 to about 3.75 wt %, about 0.075 to about 2.5 wt %, or about 0.125 to about 1.25 wt %, based on the weight of the underlying particle.

[0116] A cross section of a finished coated particle having an underlayer particle 22 and four layers 24a, 24b, 24c, and 24d is shown in Figure 2. In some embodiments, layer 24a is a carrier powder. In other embodiments, 24b is a carrier powder disposed between coating layers 24a and 24c, and 24d is an additional coating layer disposed on 24c. In yet other embodiments, 24c is a carrier powder disposed between coating layers 24b and 24d, and 24a is a coating layer disposed directly on uncoated particle 22. In yet other embodiments, 24d is a carrier powder disposed on coating layers 24a, 24b, and 24c.

[0117] A cross section of a finished coated particle according to another embodiment is shown in Figure 3. In one aspect, the coated particle includes an underlayer particle A-1, polyurethane and wax coating layers B-1, B-2, and B-3, a polyurethane coating layer (without wax sealant) C-1, and a microbial consortium-containing carrier powder D-1.

[0118] The coated particles have a controlled release or burst rate depending on the underlying particles. For example, if the underlying particles are fertilizers, the coating can slowly release nutrients to plants. More specifically, when water penetrates the coating, the fertilizer goes into solution and is forced out of the pores of the coating, ultimately leaving behind a residual (or empty) coating shell. Microorganisms are slowly released onto the surface of the residual coating shell until all of the polymers in the coating shell are decomposed.

[0119] When the sublayer particles are seeds, the coating can protect the seeds for a predetermined period of time, allowing the seeds to have a longer dormancy period than conventional seeds. In fact, coated seeds according to the present disclosure have an initial germination rate, i.e., a germination rate in the first growing season, that is equal to or greater than that of uncoated seeds, and further have a germination rate in the second growing season that is at least about 90% of the initial germination rate. In some aspects, the controlled burst rate is based on the thickness or weight percent of the coating applied to the seeds. In this regard, the coated particles may have a burst rate of at least about 20 days after planting in soil. In one embodiment, the coated seeds may have a delayed burst / germination rate of at least about 90 days after planting in soil. In another embodiment, the delayed burst / germination rate is at least about 120 days after planting in soil. In another embodiment, the delayed burst / germination rate is at least about 150 days after planting in soil. In another embodiment, the delayed burst / germination rate is at least about 180 days after planting in soil. In yet another embodiment, the delayed bursting / germination rate is at least about 210 days after planting in soil.

[0120] The burst speed can be further controlled for specific geographical regions. In this embodiment, the thickness or weight percent of the coating can be adjusted for planting in different climates. Many factors affect the timing and speed of seed germination in various geographical regions. For example, environmental factors such as the length of the growing season, the number of hours of sunshine per day, soil temperature, soil type and mineral structure, soil pH, and soil water-holding capacity all affect seed germination. Additionally, factors such as seed planting depth, excessive water / flooding (which can cause seed rot), wet and frozen conditions (which can damage the seed protective coating), seed parchment due to excessive heat, and / or soil insect infestation can adversely affect seeds planted during the desired dormancy period. The coating advantageously provides an isolation barrier for the seeds against extreme weather conditions, a guard against harmful insects, and protects seeds, especially seeds planted before the growing season, such as in late autumn and winter, from moisture and / or freezing conditions. In this embodiment, the coating on the seeds will have a controllable burst rate that promotes and / or facilitates germination during the primary growth period.

[0121] In this aspect, the coated particles of the present disclosure increase seed dormancy (from planting in soil to germination) by at least about 70% compared to uncoated seeds. In one embodiment, seed dormancy is increased by at least about 80% over that of uncoated seeds. In another embodiment, seed dormancy is increased by at least about 95% over that of uncoated seeds. When coated seeds burst and germinate, a residual (or empty) coating shell remains. The present disclosure provides a residual coating shell that is decomposed by microorganisms impregnated in the coating shell. More specifically, the microorganisms are slowly released onto the surface of the residual coating shell until all of the polymers in the coating shell are decomposed. [Example]

[0122] The following example is not intended to limit the invention or claimed subject matter, but rather to further illustrate one embodiment of the present disclosure.

[0123] [Example 1] 4% polymer-coated urea containing 0.25% microbial carrier powder

[0124] The high-speed mixer / coater was preheated to a temperature of approximately 50°C to 65°C. During preheating, the rotating pan and rotor were operated clockwise at 6.00 m / s and 1.95 m / s, respectively. Once preheated, 4536 g of uncoated urea with an average particle diameter of 3.0 to 3.5 mm was added to the mixer. The uncoated urea was preheated to a temperature of approximately 65°C to 70°C. Once this preheating was achieved, the mixer parameters were adjusted for the coating process. The rotating pan was operated clockwise at a speed of 12.00 m / s, and the rotor was operated counterclockwise at a speed of 6.00 m / s. Next, 15.9 g of polyol was added to the mixer and mixed for 30 seconds, followed by 25.6 g of isocyanate. These ingredients were rotated and allowed to react for 60 seconds, after which 7.9 g of molten wax was added and rotated for an additional 30 seconds. After repeating the polyol, isocyanate, and wax addition steps and mixing time a second time, 11.8 g of diatomaceous earth / microbial powder was added to the mixer / coater. After mixing the carrier powder for 45 seconds, a third charge of polyol, isocyanate, and wax was applied and allowed to cure for 60 seconds. The final outer coating layer was applied by first adding the polyol to the mixer / coater, waiting 30 seconds, applying the isocyanate, followed by a 60-second rotation time. Once the coating process was complete, the coated fertilizer was cooled to approximately 35°C using ambient air.

[0125] [Example 2] 4% polymer-coated urea containing 0.75% microbial carrier powder

[0126] The high-speed mixer / coater was preheated to a temperature of approximately 50°C to 65°C. During preheating, the rotating pan and rotor were operated clockwise at 6.00 m / s and 1.95 m / s, respectively. Once preheated, 4536 g of uncoated urea with an average particle diameter of 3.0 to 3.5 mm was added to the mixer. The uncoated urea was preheated to a temperature of approximately 65°C to 70°C. Once this preheating was achieved, the mixer parameters were adjusted for the coating process. The rotating pan was operated clockwise at a speed of 12.00 m / s, and the rotor was operated counterclockwise at a speed of 6.00 m / s. Next, 15.9 g of polyol was added to the mixer and mixed for 30 seconds, followed by 25.7 g of isocyanate. These ingredients were rotated and allowed to react for 60 seconds, after which 7.9 g of molten wax was added and rotated for an additional 30 seconds. After repeating the polyol, isocyanate, and wax addition steps and mixing time a second time, 35.7 g of diatomaceous earth / microbial powder was added to the mixer / coater. After mixing the carrier powder for 45 seconds, a third charge of polyol, isocyanate, and wax was applied and allowed to cure for 60 seconds. The final outer coating layer was applied by first adding the polyol to the mixer / coater, waiting 30 seconds, applying the isocyanate, followed by a 60-second rotation time. Once the coating process was complete, the coated fertilizer was cooled to approximately 35°C using ambient air.

[0127] The specifications and performance of Examples 1 and 2 were tracked and recorded in Table 1. The coating weight and carrier powder amount are percentages based on the total weight of the final coated particle. The procedure for determining the nutrient release rate was as follows:

[0128] 1. Nutrient standard solutions were prepared by dissolving various known concentrations of nutrients in distilled water. 2. Measure the refractive index of known concentrations with a refractometer and create a calibration curve of refractive index versus concentration. 3. Next, accurately weigh 10g of coated fertilizer granules into a small jar and add 100g of water. 4. Gently swirl the sample and place it in a laboratory oven at 22°C for the specified period. Before each measurement, gently swirl the sample to ensure homogeneity. Place a small sample of the solution from the sample jar in the refractometer and record the reading. 5. Nutrient concentrations in solution are obtained by comparison with the calibration curve. The percentage of nutrients released from the coated fertilizer particles is calculated.

[0129] [Table 1]

[0130] The coating thickness in Examples 1 and 2 is about 27 μm.

[0131] Visual observation of the empty coating shells demonstrated degradation of the empty shells within a few weeks after the particles would have been released into the plant. Example 1 had complete degradation of the polymer coating within 48 months. As shown in Figure 4, Example 2 had over 30% degradation of the polymer coating at 12 months, over 65% degradation of the polymer coating at 24 months, and complete degradation of the polymer coating at 36 months.

[0132] [Example 3] 2.25% polymer-jacketed calcium nitrate containing 0.25% microbial carrier powder

[0133] Using a process similar to that of Example 1, calcium nitrate was jacket coated, i.e., a relatively thin coating (compared to Examples 1 and 2) was applied for storage purposes, blend compatibility, or a combination thereof. In this embodiment, a high-speed mixer / coater was preheated to a temperature of approximately 50°C to 65°C. During preheating, the rotating container and rotor were operated clockwise at 6.00 m / s and 1.95 m / s, respectively. Once preheated, 4536 g of uncoated calcium nitrate having an average particle diameter of 3.0 to 3.5 mm was charged into the mixer. The uncoated calcium nitrate was preheated to a temperature of approximately 55°C to 65°C. Once this preheating was achieved, the mixer parameters were adjusted for the coating process. The rotating pan was operated clockwise at a speed of 12.00 m / s, and the rotor was operated counterclockwise at a speed of 6.00 m / s. Next, 13.4 g of polyol was charged into the mixer and mixed for 30 seconds, followed by 21.5 g of isocyanate. These ingredients were tumbled and allowed to react for 60 seconds, after which 11.6 g of molten wax was added and tumbled for an additional 30 seconds. Next, 11.6 g of diatomaceous earth / microbial powder was added to the mixer / coater. After mixing the carrier powder for 45 seconds, the final outer coating layer was applied by first adding the polyol to the mixer / coater, waiting 30 seconds, applying the isocyanate, followed by a 60-second tumble time. Once the coating process was complete, the coated calcium nitrate was cooled to approximately 35°C using ambient air.

[0134] The thickness of the jacket coating in Example 3 is about 12 μm. As shown in Figure 5, Example 3 has about 50% degradation of the polymer coating at 12 months, more than 70% degradation of the polymer coating at 18 months, and complete degradation of the polymer coating at 24 months. Comparing Figures 4 and 5, the coated particles of Example 2 take about 5 months more (almost 17 months) to achieve about 50% degradation compared to Example 3.

Claims

1. Coated particles, The core and a first coating layer disposed on the core, the first coating layer comprising a coating formulation and a wax; a carrier impregnated with a microbial consortium and applied to the first coating layer in an amount of about 0.1 to about 1.0% by weight of the coating particles; and a second coating layer disposed on the carrier and comprising the coating formulation; a coating shell comprising 1. A coated particle comprising: a microbial consortium having a functional period, the microbial consortium comprising a plurality of microorganisms capable of substantially biodegrading the coating shell within a target period, the target period being about 48 months or less after the end of the functional period.

2. The coated particle of claim 1 , wherein the core comprises a fertilizer.

3. The coated particle of claim 1 , wherein the core comprises a seed.

4. The coated particle of claim 1 , wherein the coating formulation comprises a polyurethane.

5. 5. The coated particle of claim 4, wherein the polyurethane is a reaction product of a polyisocyanate and a polyol.

6. 6. The coated particle of claim 5, wherein the plurality of microorganisms comprises a first set of microorganisms capable of degrading the coating formulation and a second set of microorganisms capable of degrading the wax.

7. 10. The coated particle of claim 1, wherein the plurality of microorganisms comprises at least two or more microorganisms classified as Biosafety Level 1 organisms.

8. The coating shell is a third coating layer disposed between the first coating layer and the carrier, the third coating layer comprising the coating formulation and a wax; and a fourth coating layer disposed between the carrier and the second coating layer, the fourth coating layer comprising the coating formulation and a wax; The coated particle of claim 1 further comprising:

9. The coated particles of claim 1 , wherein the carrier is a powder.

10. The core and a carrier impregnated with a microbial consortium and applied to said core; a first coating layer disposed on the carrier, the first coating layer comprising a coating formulation and a wax; and a second coating layer comprising the coating formulation and disposed on the first coating layer; a coating shell comprising A coated particle comprising: A coated particle having a functional period, wherein the microbial consortium is capable of substantially degrading the coating shell no more than about 48 months after the end of the functional period.

11. The coated particle of claim 10 , wherein the core comprises a fertilizer.

12. The coated particle of claim 10 , wherein the core comprises a seed.

13. The coated particle of claim 10 , wherein the coating formulation comprises a polyurethane.

14. 14. The coated particle of claim 13, wherein the microbial consortium comprises a first set of microorganisms capable of degrading the coating formulation and a second set of microorganisms capable of degrading the wax.

15. The coated particle of claim 14 , wherein the carrier is a powder.

16. The core and a first coating layer disposed on the core, the first coating layer comprising a coating formulation; and a carrier powder disposed on the first coating layer and impregnated with a microbial consortium; a coating shell comprising A coated particle comprising: A coated particle having a functional period, wherein the microbial consortium comprises a plurality of microorganisms capable of substantially degrading the coating shell within a target period, the target period being no more than about 48 months after the end of the functional period.

17. 17. The coated particle of claim 16, wherein the core comprises a fertilizer.

18. The coated particle of claim 16 , wherein the core comprises a seed.

19. The coated particle of claim 16 , wherein the coating formulation comprises a polyurethane.

20. 20. The coated particle of claim 19, wherein the polyurethane is a reaction product of a polyisocyanate and a polyol.

21. 20. The coated particle of claim 19, wherein the plurality of microorganisms comprises a first set of microorganisms capable of degrading the coating formulation and a second set of microorganisms capable of degrading the wax.

22. 17. The coated particle of claim 16, wherein the plurality of microorganisms comprises at least two microorganisms classified as Biosafety Level 1 organisms.

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