IL313232B2

IL313232B2 - Controlled-release active agents having biodegradable coatings

Info

Publication number: IL313232B2
Application number: IL313232A
Authority: IL
Inventors: Yaniv Isaac
Original assignee: Oris Advanced Mat Ltd; Yaniv Isaac
Priority date: 2024-05-30
Filing date: 2024-05-30
Publication date: 2025-04-01
Also published as: IL313232A; IL313232B1; WO2025248514A1

Description

Attorney Ref. No. 531/5.

CONTROLLED-RELEASE ACTIVE AGENTS HAVING BIODEGRADABLE COATINGS FIELD [0001] Embodiments of the invention relate to compositions comprising controlled-release active agents having biodegradable coatings, comprising agricultural active agents such as fertilizer, pesticides, or nutritional agents. BACKGROUND [0002] In the agricultural industry, many chemical compositions are provided to crops or to livestock to assist in the growing of the crops and livestock. For example, fertilizers are frequently administered during the growth of crops for promotion of plant growth and yield. Fertilizers comprising three macro nutrients, nitrogen (N), phosphorus (P), and potassium (K) are typically administered to crops. When administered together, these fertilizers are referred to as NPK fertilizers. Other nutrients such as calcium, magnesium, and sulfur, as well as micronutrients such as copper, iron, manganese, molybdenum, zinc, boron, silicon, cobalt and vanadium are also administered to plants during plant growth. Urea is a common chemical administered to plants as a source of nitrogen. [0003] As many common fertilizers are water-soluble, excess fertilization and subsequent runoff into bodies of water may cause environmental problems. In order to allow more efficient administration of fertilizer, controlled-release fertilizers (CRF) have been developed, to provide release of the fertilizer over an extended period of time after administration to a crop. Such compositions may be useful to prevent loss of fertilizers by rain or irrigation, or to allow for fewer applications thereby leading to lower labor and equipment costs. [0004] Although CRF may be advantageous to prevent over-fertilization and negative environmental impacts, substantial environmental downsides of using CRF remain. Currently many CRF are coated by various polymers, including microplastics which remain in the soil, occasionally for years after the administration of the fertilizer is complete. Microplastics are solid particles of plastic materials composed of mixture of polymers and functional additives. The European Regulation (Article 3(5) of Regulation (EC) No 1907/2006) definition for microplastics is: particles of certain dimension between 0.1 micron to 5 mm or fibers at the length of 0.3 to mm and length to diameter ratio greater than 3. According to the regulation, no product containing Attorney Ref. No. 531/5. 0.01% (w/w) shall be put intentionally in the EU market. This regulation severely limits the use of CRF containing materials which can be classified as microplastics. [0005] In addition to CRF, controlled-release pesticides are used in agriculture. Pesticides are compositions which are administered in the vicinity of crops and other agricultural products to kill or limit the growth of a pest which negatively impacts the growth of the crop. The pest may be a plant such as a weed, or fungi, or insects. A pesticide which is used to limit the growth of a plant which negatively affects the crop, the pesticide is known as a herbicide. [0006] Other controlled-release compositions used in agriculture include non-protein nitrogen (NPN) which is administered to livestock. As livestock typically require protein as part of their diet, an efficient way to provide protein to livestock such as ruminants is administration of non-protein nitrogen. Some examples of nitrogen-containing chemical compounds used for NPN include urea, biuret, and ammonia. Microbes in the livestock digestive system convert these nitrogen-containing compounds to compounds used to make protein. As NPN is typically less costly than plant-based protein, using NPN to replace some of the plant-based protein in ruminant diet provides an inexpensive method for increasing ruminant growth. As feeding NPN to livestock can release ammonia in the rumen, this may be potentially toxic to the livestock by elevating blood urea nitrogen levels. To avoid high concentrations of NPN in livestock diet, slow-release compositions comprising NPN have been developed to maintain a steady flow of NPN to livestock gut microbes without inducing ammonia-induced toxicity. An example of a commercial product comprising slow-release NPN is Optigen® by Alltech (Nicholasville, KY, USA). SUMMARY [0007] Described herein, according to an embodiment, is a coated agricultural composition, comprising: an active agent; and a hard hydrophobic coating surrounding the active agent, the coating comprising Portland cement and a fatty acid. [0008] Further described herein according to embodiments, are methods for coating active agents comprising: obtaining an active agent; and contacting the active agent with Portland cement and a fatty acid. DETAILED DESCRIPTION [0009] Unless otherwise noted, technical terms are used according to conventional usage.

Attorney Ref. No. 531/5. id="p-10" id="p-10" id="p-10" id="p-10" id="p-10"

[0010] Unless otherwise explained, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure unless context clearly clearly indicates otherwise. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of this disclosure, suitable methods and is derived from the Latin exempli gratia and is used herein to indicate a non-limiting example. Thus, the a [0011] In case of conflict, the present specification, including explanations of terms, will control. In addition, all the materials, methods, and examples are illustrative and not intended to be limiting. [0012] Terms: Active agent: a chemical substance or biological agent which enhances agricultural production, whether in crops or livestock. An active agent may include a fertilizer, a pesticide, a nutrient or a seed. [0013] Fatty acid: a carboxylic acid with an aliphatic chain. Fatty acid moieties are included within the definition of fatty acids. [0014] Fertilizer: a composition administered to crops, typically to soil, to increase crop growth. [0015] NPK: synthetic fertilizer comprising compounds or salts containing nitrogen, phosphorus, and potassium. [0016] NPN: (non-protein nitrogen) a nitrogen-containing compound administered to animals such as ruminants, which the animal is capable of converting to protein. Urea, biuret and ammonia are common examples of NPN. [0017] Pesticide: compositions which are administered in the vicinity of crops and other agricultural products to kill or limit the growth of a pest which negatively impacts the growth of the crop or agricultural product. [0018] Portland Cement: a that hardens by reacting with water and forms a water-resistant product. Portland cement comprises calcium silicates: tricalcium silicate (3CaO ꞏ SiO2), dicalcium silicate (2CaO ꞏ SiO2); and tricalcium aluminate (3CaO ꞏ Al2O3), and a tetra-calcium Attorney Ref. No. 531/5. aluminoferrite (4CaO ꞏ Al2O3Fe2O3). Portland cement may comprise additional materials such as iron oxides which impact the color of the Portland cement, and calcium sulfate. [0019] Tall oil: a byproduct of wood pulp manufacture, comprising fatty acids. [0020] Described herein, according to an embodiment, are novel compositions comprising a core having an active agent, preferably one used in agriculture, and a coating. The coating is formed by combining Portland cement with a fatty acid. [0021] It has been surprisingly found by the inventor, that compositions described herein are advantageous in that they demonstrate controlled/ delayed release of agricultural active agents such as fertilizers, and are biodegradable, as they comprise coatings without synthetic polymers/ plastics. They can serve as CRF, but have an advantage over current CRF in that no microplastics are formed when the compositions described herein are used in agricultural industries. In addition, the starting materials are based on natural minerals and are inexpensive. A primary ingredient in the coatings is Portland cement, which is readily available worldwide, and is an inexpensive raw starting material, used in the construction industry. Similarly, fatty acids can be used, such tall oil, which comprises free fatty acids and is a relatively inexpensive byproduct of the paper milling industry. [0022] According to some embodiments, compositions described herein are capable of releasing not more than 15% of their active agent over the course of the first 24 hours when in contact with water. Optionally, compositions described herein are capable of releasing active agent over the course of greater than 30 days when in contact with water. [0023] Without being bound by theory, it is suggested that in coated compositions according to embodiments of the invention, the fatty acid reacts with the calcium silicate present in the cement to form insoluble carboxylate salts of the calcium silicate and forms a hard hydrophobic coating surrounding the active agent. The hard hydrophobic coating, when in an aqueous environment, limits the flow of water in and out of the coated active agent, thereby limiting the release of water-soluble active from the composition. [0024] Other uses of the hard hydrophobic coating described herein include coating of active agents to prevent their reaction with other active agents. For example, in case of the active agent urea, a hard hydrophobic coating may be applied, and a mixture may then be formed with coated urea and other fertilizers such as single superphosphate (SSP) or triple superphosphate (TSP), thereby allowing the fertilized to be blended and stored together without forming a chemical Attorney Ref. No. 531/5. reaction between the urea and the SSP or TSP. In such cases, the coating layer may be as low as about 5% of the weight of the composition, as the coating does not necessarily need to provide sustained release properties. It should be noted that fine particles, such as powders of active agent, including micronutrients can be coated using the same methods while the coating agent (i.e Portland Cement +Fatty Acid) serves also as a binder in order to form a granular product. [0025] Optionally, the active agent is selected from the group consisting of: a fertilizer, a pesticide, a nutritional agent, and a seed. Optionally, the fertilizer is a nitrogen-containing fertilizer such as urea. The fertilizer may be an NPK fertilizer. Optionally, the nutritional agent is selected form the group consisting of NPN and an amino acid. Other fertilizers which may be used include but are not limited to potassium nitrate, potassium sulfate, potassium chloride, monoammonium phosphate, diammonium phosphate and calcium ammonium nitrate. [0026] According to an embodiment, the composition is in granular form, optionally having a particle diameter of between 0.1 -5 mm. optionally, in the range of 0.5-4 mm, or 1-4 mm, optionally for 90% by weight or more of the composition. [0027] According to an embodiment, the Portland cement used in the coated compositions described herein is white Portland cement. According to an embodiment, the Portland cement used in the coated compositions described herein is white Portland cement. Optionally, the cement is selected from the group consisting of: CEM type I, 52.5 R (White and Grey), CEM type I, 52.5 N, and CEM type II, 42.5 AL. All Portland cement contained more than 60% of CaO and more than 15% of SiO2. [0028] The fatty acid used to form the coating of the compositions described herein, according to some embodiments, may be C10-C20 fatty acid. The fatty acid may be a saturated or unsaturated fatty acid, optionally an unsaturated fatty acid. Mixtures of various types of fatty acids may be used. According to an embodiment, the unsaturated fatty acid is oleic acid. Optionally, the fatty acid used for the coating is in the form of a mixture, in form of a liquid composition comprising a fatty acid, or multiple types of fatty acid. Preferably, the liquid composition comprises at least 50% fatty acid, preferably at least 70% fatty acid. Optionally the liquid composition comprising fatty acid is tall oil, or tall oil fatty acid. [0029] According to an embodiment, the coated agricultural composition comprises a hard hydrophobic coating surrounding the active agent, in an amount of between 5% by weight and 50% by weight of the coated agricultural composition, optionally, between 10% and 30% by Attorney Ref. No. 531/5. weight of the coated agricultural composition. Optionally, the amount of coating, by weight, is less than 20% of the coated agricultural composition. [0030] According to an embodiment, the percentage, by weight, of fatty acid in the coating layer is 15%-45%, optionally 30%-40%. [0031] According to an embodiment, the coating layer comprises, in addition to Portland cement and a fatty acid, a mineral filler. The mineral filler is optionally a metal oxide, optionally CaO or MgO. Optionally, the mineral filler is selected from the group consisting of CaO, MgO, CaCO3, a kaolin, and clay. Optionally, the mineral filler is CaO and/ or MgO. The ratio of Portland cement to mineral filler may be between 1:10 and 10:1. Optionally, the ratio of Portland cement to mineral filler is between 1:3 and 3:1. [0032] According to an embodiment, described is a coated agricultural composition, consisting essentially of: an active agent; and a hard hydrophobic coating surrounding the active agent, the coating consisting essentially of Portland cement and a fatty acid, optionally further consisting essentially of a mineral filler. [0033] According to an embodiment, described herein are methods for coating active agents comprising: obtaining an active agent; and contacting the active agent with Portland cement and a fatty acid. Optionally, the active agent is in the form of a granule, which is contacted by a liquid fatty acid composition, wherein the fatty acid is a free fatty acid. After contacting the granule with the liquid fatty acid composition, Portland cement, optionally in combination with a mineral filler, is added. Upon addition, Portland cement and fatty acid react and begin to harden. Upon hardening and formation of a first layer, additional liquid fatty acid and Portland cement may be added to the coated active agent to form a second layer. This process may be repeated, optionally between 2-6 times for each batch of coated active agents. Optionally, granules are coated with a coating using a rotating apparatus such as a rotating drum apparatus. [0034] The methods described herein may be performed with active agent, Portland cement, fatty acid composition and optionally mineral filler, using types described above, and in ratios as described above. [0035] The methods described herein may be performed at room temperature. No heating is required to perform these methods, therefore only small amounts of energy may be used in preparing such compositions. The method described herein does not produce effluents and/or other by products which negatively impacts the environment.

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[0036] Further described herein are compositions as described above, for use in assisting the growth of a plant or an animal. [0037] The following examples are provided to illustrate certain particular features and/or embodiments. These examples should not be construed to limit the disclosure to the features or embodiments described. EXAMPLES [0038] Example 1: Evaluation of reactions between oils and fatty acid compositions and Portland Cement [0039] To determine if various oils and fatty acid-containing compositions (liquid reagents) could harden upon contact with Portland cement, liquid reagents were combined, in a ratio of 10 g of Portland cement to 2 g of liquid reagent, at a temperature of 25°C, and their hardening time was measured, and is presented below in Table 1. Oleic acid (C 18:1-79.8%; C18:2-12.3%) was obtained from Chen Samuel Chemicals Ltd. Tall oil fatty acid and tall oil were both obtained from Ingevity (North Charleston, SC, USA). Tall oil (Altavag 3030) comprises 75% fatty acid and 25% rosin acid. Tall oil fatty acid (Altapyne L-5-A) comprises 93% fatty acid. White Portland Cement is type CEM I, 52.5 R, produced by Oyak, Cimento, Turkey. Gray Portland Cement 1 is CEM I 52.5 N, produced by Medcem, Turkey. Gray Portland Cement 2 is CEM I, 52.5 R, and produced by Nesher Cement, Israel. Gray Portland Cement 3 is CEM II 42.5 R AL, and produced by Nesher Cement, Israel. Soybean oil, canola oil, and olive oil were all commercially available food-grade oils. [0040] Table 1: Liquid Reagent White Portland Cement Gray Portland Cement Gray Portland Cement Gray Portland Cement Oleic Spontaneous Solidification (Exothermic) Solidification after 2 to minutes Solidification after to minutes Solidification after 5 to minutes Attorney Ref. No. 531/5.

Tall oil fatty acid Spontaneous Solidification (Exothermic) Solidification after 2 to minutes Solidification after 5 to minutes Solidification after 5 to minutes Tall oil Spontaneous Solidification Solidification after 2 to minutes Solidification after 5 to minutes Solidification after 5 to minutes Soybean oil Viscous paste After few weeks Does not solidify Viscous paste After few weeks Does not solidify Viscous paste After few weeks Does not solidify Viscous paste After few weeks Does not solidify Canola oil Viscous paste After few weeks Does not solidify Viscous paste After few weeks Does not solidify Viscous paste After few weeks Does not solidify Viscous paste After few weeks Does not solidify Olive oil Viscous paste After few weeks Does not solidify Viscous paste After few weeks Does not solidify Viscous paste After few weeks Does not solidify Viscous paste After few weeks Does not solidify [0041] As seen in table 1, when various types of Portland cement was combined with compositions comprising free fatty acids in amounts of 75% and above, including oleic acid, tall oil and tall oil fatty acid, the cement solidified either rapidly, or within a few minutes through an exothermic reaction to form a hard, hydrophobic coating, indicating that they would be feasible for use for biodegradable coatings of active agents. As soybean, canola and olive oil contain primarily triacylglycerols, these liquid reagents when combined with Portland cement formed a Attorney Ref. No. 531/5. viscous paste and did not solidify, even after a month, and therefore are not acceptable for preparing coatings of active agents. [0042] Example 2A: Manufacture of coated active agent [0043] Coated active agents comprising fertilizer were prepared using the following general method: active agent granules, at a weight of 60 g, were introduced into a rotating drum having a diameter of 15 cm and were rotated at a speed of between 30-100 revolutions per minute. Liquid fatty acid-containing composition was sprayed via a pipet nozzle over the fertilizer surface while rotating, over the course of a few minutes. After coating, a measured amount of Portland cement powder, optionally comprising an additive, was added to the rotating drum. After a first layer was completed and dried, subsequent layers were added by returning to the step of spraying liquid fatty acid-containing composition, then further addition of Portland cement powder, optionally comprising an additive. The coating process is performed at ambient conditions. [0044] Example 2B: Analysis or release profile of coated active agents [0045] Coated active agents were placed in a plastic container filled with tap water maintained at 25°C ±2°C, at a ratio by weight of 1 part coated active agent to 10 parts water. Analyses were performed at various time intervals between 1 day and 60 days. Each 5 days, about 50% of the water in each container was replaced by fresh tap water. At the end of the designated time, the Fertilizer was filtered out of the water and placed in a drying oven at 80°C for 8 hours until fully completion of drying, and weighed, and compared to the starting weight. As the coating is practically water insoluble, and the active agents used in the experiments are highly soluble, it is assumed that the weight loss is attributable to the release of the active agent only. [0046] Example 3A: Manufacture of coated fertilizer, and analysis of release profile [0047] The procedure of Example 2A was followed to coat urea active agent with white Portland cement type CEM I, 52.5 R. The urea used was produced by Chen Samuel Chemicals Ltd. (Kiryat Ata, Israel) and was in the form of granules, having a diameter of 1-4 mm, and 60 g of urea were used in the example. Each coating layer contained 1 g of oleic acid and 1.6 g of white cement. After each coating and self-drying, the sample was weighed, and the number of coatings, weight, coating weight and percentage urea by weight is listed in table 2 below. [0048] Table 2: Attorney Ref. No. 531/5.

Sample Number of coatings Total weight of coating in grams Total sample weight in grams Percent Urea 1 2 5.2 65.2 92. 2 3 7.8 67.8 88. 3 4 10.4 70.4 85. 4 5 13.0 73.0 82. 6 15.6 75.6 79. [0049] Samples prepared were tested for release profile using the method of Example 2B, at time intervals between 1 and 60 days. The results of percent weight loss are shown in table below. [0050] Table 3: Sample 1 Day 5 Days 15 Days 30 Days 45 Days 60 Days 1 63.6% - - - - - 2 23.3% 50.8% 65.1% 75.2% - - 3 10.0% 27.5% 50.2% 75.1% 83.6% - 4 2.35% 9.4% 20.0% 33.0% 38.3% 43.0% 2.15% 3.1% 5.0% 5.5% 12.9% 18.0% [0051] As shown in Table 3, increase in number of coating layers decreases the release of the urea from the coated composition. In samples 3, 4, and 5, an acceptable release profile was shown, as less than 15% of the urea was released in the first day, and the composition continues to release urea over 30 days. This release rate was attained using a coated composition comprising about 10-16% coating by weight. The ratio of fatty acid to cement was about 1:1.6 by weight in the coating. [0052] Example 3B: Manufacture of coated fertilizer, and analysis of release profile [0053] The procedure of Example 2A was followed to coat urea with gray Portland cement 1. Each coating layer contained 1 g of oleic acid and 2.2 g of Portland cement. After each coating Attorney Ref. No. 531/5. and drying, the sample was weighed, and the number of coatings, weight, coating weight and percentage urea by weight is listed in table 4. [0054] Table 4: Sample Number of coatings Total weight of coating in grams Total sample weight in grams Percent Urea 6 3 9.6 69.6 86. 7 4 12.8 72.8 82. 8 5 16.0 76.0 78. 9 6 19.2 79.2 75. [0055] Samples prepared were tested for release profile using the method of Example 2B, at time intervals between 1 and 60 days. The results of percent weight loss are shown in table below. [0056] Table 5: Sample 1 Day 5 Days 15 Days 30 Days 45 Days 60 Days 6 18.5% 47.1% 65.8% 70.0% 87.4% - 7 16.5% 20.9% 43.8% 61.7% 84.7% - 8 8.4% 10.6% 20.2% 61.4% 67.3% - 9 6.0% 10.6% 14.7% 16.5% 48.4% 66.8% [0057] As shown in Table 5, increase in number of coating layers decreases the release of the urea from the coated composition over time. In samples 8 and 9, an acceptable release profile was shown, as less than 15% of the urea was released in the first day, and the composition continues to release urea over 30 days. Sample 9 showed release of urea even at 60 days. This release rate was attained using a coated composition of gray Portland cement (CEM I 52,5 N) comprising about 15-20% coating by weight. The ratio of fatty acid to cement was about 1:2.2 by weight in the coating. [0058] Example 3C: Manufacture of coated fertilizer comparing number of coatings Attorney Ref. No. 531/5. id="p-59" id="p-59" id="p-59" id="p-59" id="p-59"

[0059] Two additional samples were made with white Portland cement, having similar amounts of ingredients as Sample 4 of example 3A to determine if numbers of coatings impacts release profile. Here too, 60 g of urea were used, and coating layers, as well as oleic acid and cement amounts per layer are shown in Table 6 below. The general procedure for the manufacture was performed as in Example 2A. [0060] Table 6: Sample Number of coatings Weight of oleic acid per layer in grams Weight of white Portland cement per layer in grams Total Coating Weight in grams Percent Urea 4 5 1 1.6 13.0 82. 2 2.5 4.0 13.0 82. 11 3 1.6 2.7 12.9 82. [0061] Samples prepared were tested for release profile using the method of Example 2B, at time intervals between 1 and 45 days. The results of percent weight loss are shown in table below. [0062] Table 7: Test No No of Coating Layers Day 1 Day 5 Day 15 Day 30 Day 4 5 2.35% 9.4% 20.0% 33.0% 38.3% 2 1.8% 2.7% 14.8% 33.2% 41.6% 11 3 1.1% 5.7% 14.5% 31.4% 42.1% [0063] As shown in table 7, sample 4 showed a slightly more delayed release profile relative to samples 10 and 11 at 45 days, even though at days 1, 5, and 15, more release was evident in sample 4. More coatings require more coating processing time, but may increase long-term (days and more) resistance to release. [0064] Example 3D: Manufacture of coated fertilizer with various types of Portland cement Attorney Ref. No. 531/5. id="p-65" id="p-65" id="p-65" id="p-65" id="p-65"

[0065] Additional samples were made with various types of Portland cement, and were compared with Sample 11 from Example 3C. The general procedure for the manufacture was performed as in Example 2A. Here too, 60 g of urea were used, and coating layers, as well as oleic acid and cement amounts per layer are shown in Table 8 below. Sample 11 was prepared with white Portland cement. Sample 12 was prepared with gray Portland cement 1. Sample 13 was prepared with gray Portland cement 2. Sample 14 was prepared with gray Portland cement 3. The compositions of the cement and their respective setting times (in minutes) are shown in Table 9. [0066] Table 8: Sample Number of coatings Weight of oleic acid per layer in grams Weight of white Portland cement per layer in grams Total Coating Weight in grams Percent Urea 11 3 1.6 2.7 12.9 82. 12 3 1.6 3.0 13.8 81. 13 3 1.6 3.4 15.0 80. 14 3 1.6 3.4 15.0 80. [0067] Table Cement type % CaO % SiO2 Setting Time White Portland cement 65.8 21.7 Gray Portland cement 1 64.65 19.60 Gray Portland cement 2 61.1 18.3 1 Gray Portland cement 3 60.3 16.8 1 [0068] Slightly more cement was used when combining Gray Portland cement 2 and 3 with oleic acid due to the slower setting time of these types of cement. [0069] The release rates of urea were measured according to the procedure in example 2B and the results are shown in Table 10 below, at time points between 1 and 30 days. [0070] Table 10: Attorney Ref. No. 531/5.

Sample Type of Cement Day 1 Day 15 Day 11 White Portland Cement 1.1% 14.5% 31.4% 12 Gray Portland Cement 1 2.75% 34.4% 46.9% 13 Gray Portland Cement 2 10.4 25.5% 46.3% 14 Gray Portland Cement 3 9.85% 26.2% 41.8% [0071] All samples 11-14 showed acceptable results, however Gray Portland Cement and 3 showed rapid release of urea on day 1. [0072] Example 3E: Manufacture of coated fertilizer with various types of Portland cement and fatty acid [0073] Additional samples were made with various types of Portland cement and fatty acid containing compositions such as tall oil fatty acid (L-5-A) and tall oil (3030). The general procedure for the manufacture was performed as in Example 2A. [0074] For each sample, 60 g of urea were used. Coating layers, including cement type and amount, and fatty acid type and amount, is detailed in Table 11 below. [0075] Table 11: Sample No of Coating Layers Type of Portland Cement Type of Carboxylic Liquid Weight of fatty acid composition in grams Total weight of Cement in grams Total Weight of coating in grams Percent Urea 4 5 White Oleic acid 5.0 8.0 13.0 82. 5 White Tall oil fatty acid 5.0 8.0 14.0 82. 16 5 White Tall oil 5.0 9.0 14.0 81. 12 3 Gray 1 Oleic acid 4.8 9.0 13.8 81. 17 3 Gray 1 Tall oil fatty acid 4.8 9.0 13.8 81. 18 3 Gray 1 Tall oil 4.8 9.0 13.8 81.3 Attorney Ref. No. 531/5. id="p-76" id="p-76" id="p-76" id="p-76" id="p-76"

[0076] Samples prepared were tested for release profile using the method of Example 2B, at time intervals between 1 and 30 days. The results of percent weight loss are shown in table below. [0077] Table 12: Sample Day 1 Day 15 Day 4 2.35 20.0 33. 2.65 21.4 27. 16 7.1 31.0 41. 12 2.75 34.4 46. 17 10.4 40.0 63. 18 5.8 21.4 46. [0078] As seen in Table 12, oils such as tall oil fatty acid provide similar results in release profile as oleic acid, as evident from a comparison between samples 4 and 15, which had similar release profiles at 1, 15, and 30 days. These result indicate that other fatty oil compositions may be used to combine with Portland cement to prepare biodegradable coatings for controlled release active agents. [0079] Example 4: NPK coated fertilizer [0080] An NPK fertilizer was coated with a biodegradable coating prepared using a combination of fatty acid and Portland cement, as described in Example 2A, using NPK as an active agent, and the cement and fatty acid as in Table 13. Sample 101 represents uncoated NPK. NPK was produced by Productos Flower SA Spain, and was a 12-8-21 fertilizer having also sulfur (8%) and Magnesium (3.5). The NPK was in the form of granules, having a diameter of 0.5-4 mm. [0081] Table 13: Sample Number of Coating layers Type of Portland Cement Type of fatty acid Total weight of Carboxylic liquid in grams Total weight of Cement in grams Percent NPK Attorney Ref. No. 531/5. 101 - - - - - 100.0% 102 3 Gray cement Oleic 4.2 7.2 84. 103 3 Gray cement Tall oil fatty acid 4.2 7.2 84. 104 3 Gray cement Tall oil fatty acid 4.2 7.2 84. id="p-82" id="p-82" id="p-82" id="p-82" id="p-82"

[0082] Samples prepared were tested for release profile using the method of Example 2B, at time intervals between 1 and 30 days. The results of percent weight loss are shown in table below. [0083] Table 14: Sample Day 1 Day 5 Day 15 Day 101 50.0 61.0 75.0 90. 102 17.0 32.8 44.0 50. 103 18.8 41.0 56.0 63. 104 19.5 38.0 50.0 65. [0084] As seen from Table 14 when comparing the release profile of sample 101 to samples 102-104, introduction of a biodegradable coating comprising various types of cements and fatty acids delays the release of NPK from the composition. [0085] Example 5: Coatings of fertilizer with coatings comprising additional ingredients [0086] Attempts were made to use mineral oxides with or without Portland cement to coat active ingredients. Portland cement was blended with CaO and/or MgO and metal oxides alone, or were used in place of Portland cement (samples 23 and 25) to prepare coatings, using the method described in example 2A. MgO powder was provided by Grecian Magnesite, in the form of . CaO powder was provided by Chen Samuel Chemicals and comprised 98% CaO. [0087] In each sample, 60 g of urea were used, and three coating layers were used to prepare the samples. Each coating layer comprised 1.6 g of Oleic acid, and solid filler (white Attorney Ref. No. 531/5.

Portland cement + metal oxide, or metal oxide alone) was used in the amounts and ratios described in table 15. Sample 11, using white Portland cement alone in combination with oleic acid was described above in example 3C. [0088] Table Sample Type of Metal Oxide Weight ratio of Metal oxide/ white cement Solid filler weight per coating layer in grams Total Coating weight in grams Percent Urea 11 - Pure white Portland cement 2.7 12.9 82. 19 CaO 1/3 2.7 12.9 82.

CaO 1/1 2.6 12.6 82. 21 CaO 3/1 2.6 12.6 82. 22 CaO 10/1 2.5 12.3 83. 23 CaO Pure CaO 2.5 12.3 83. 24 MgO 3/1 3.0 13.8 81.

MgO Pure MgO 2.8 13.2 81. [0089] Samples prepared were tested for release profile using the method of Example 2B, at time intervals between 1 and 30 days. The results of percent weight loss are shown in table below. [0090] Table Sample Day 1 Day 5 Day 15 Day 11 1.1 5.7 14.5 31. 19 4.7 9.0 19.8 44. 8.2 21.9 32.0 49. 21 13.4 29.8 40.4 59.5 Attorney Ref. No. 531/5. 22 17.1 36.3 57.2 62. 23 23.1 57.9 70.4 85. 24 9.4 22.5 50.5 85. 30.5 65.0 73.9 -- [0091] Active agents comprising metal oxides MgO and CaO alone had rapid release profiles on day 1 (over 20%) and day 5 (over 50%), making these coatings less suitable for coating active agents. Combinations of Portland cement with MgO and CaO did provide suitable release rates. Such combinations may be acceptable for uses in which silicate content of cement should be decreased, such as in providing ruminant nutrition in the form of NPN. [0092] Example 6: Dissolution of coated active agents [0093] Samples described in example 5 were tested for dissolution, using the following procedure. A hot plate was equipped with a magnetic stirrer. A glass beaker filled with 500 ml water was placed on the hot plate. Coated urea granules weighing 10 grams were placed in a mesh basket and the mesh basket with the urea sample was inserted in the water, which was maintained at 39°C +/- 1°C. A magnetic stirrer rotated at about 100 RPM. Weight loss of urea samples after dissolution time of 1 and 3 hours were evaluated as described above and the weight loss in terms of percentage of weight lost at these time points is listed in Table 17. [0094] Table 17: Test No 1 hr 3hr 11 5.5 15. 19 7.7 19. 8.8 22. 21 14.2 29. 22 21.0 38. 23 6.7 21. 24 30.8 42.

Attorney Ref. No. 531/5. id="p-95" id="p-95" id="p-95" id="p-95" id="p-95"

[0095] The addition of CaO or MgO to Portland cement compositions expedites the speed of the coating process, as the reaction between the fatty acid and the solid mixture of metal oxide with Portland cement and subsequent solidification is faster than the reaction between fatty acid and Portland cement alone. In addition, NPN using coated urea comprising blends of Portland Cement and metal oxides such as CaO and MgO can be effective in reducing dissolution time in , indicating that NPN can be administered in a safer, more effective way. As the combinations of Portland cement with metal oxides have lower silicate content than Portland cement alone, such combinations can be reacted with fatty acids to form coatings of NPN, and can be administered to ruminants without surpassing regulatory limits of silicate administration to the ruminants. [0096] In view of the many possible embodiments to which the principles of the disclosed invention may be applied, it should be recognized that the illustrated embodiments are only preferred examples of the invention and should not be taken as limiting the scope of the invention. Rather, the scope of the invention is defined by the following claims. We therefore claim as our invention all that comes within the scope and spirit of these claims.

Claims

1. 313232/ Claims 1. A coated agricultural composition comprising: an active agent; and a hard, hydrophobic coating surrounding the active agent, the coating comprising Portland cement and a fatty acid, wherein the fatty acid in the coating is between 15%-45% of the coating by weight.

2. The composition according to claim 1 wherein the active agent is selected from the group consisting of: a fertilizer, a pesticide, a nutritional agent, and a seed.

3. The composition according to claim 2 wherein the active agent is a fertilizer.

4. The composition according to claim 3 wherein the fertilizer is a nitrogen containing fertilizer.

5. The composition according to claim 4 wherein the fertilizer is urea or NPK.

6. The composition according to claim 1 wherein the active agent is a nutritional agent.

7. The composition according to claim 6 wherein the nutritional agent is non-protein nitrogen.

8. The composition according to any one of the previous claims wherein the active agent is a granule having a diameter of between 0.5-4 mm.

9. The composition according to any one of the previous claims wherein the Portland cement comprises more than 55% CaO and more than 15% SiO2.

10. The composition according to any one of the previous claims wherein the fatty acid is a C10-C20 fatty acid.

11. The composition according to claim 10 wherein the fatty acid is oleic acid.

12. The composition according to claim 1 wherein the fatty acid is tall oil or tall oil fatty acid.

13. The composition according to any one of the previous claims wherein the composition comprises hard hydrophobic coating in an amount of between 5% and 50% by weight of the coated composition.

14. The composition according to claim 13 wherein the composition comprises hard hydrophobic coating in an amount of between 10% to 40% by weight of the coated composition.

15. The composition according to any one of the previous claims wherein the coating layer further comprises a mineral filler. 313232/

16. The composition according to claim 16 wherein the mineral filler is selected from the group consisting of CaO and MgO.

17. The composition according to any one of claims 17-18 wherein the ratio of Portland cement to mineral filler is between 1:10 and 10:1.

18. A method for coating an active agent with a hard hydrophobic coating, comprising, a. contacting the active agent with a combination of Portland cement and a liquid fatty acid composition to form a coating, wherein the fatty acid in the coating is between 15%-45% of the coating by weight, and b. allowing the coating to harden, thereby forming a hard, hydrophobic coating.

19. The method according to claim 18 wherein the active agent is selected from the group consisting of: a fertilizer, a micronutrient, a pesticide, a nutritional agent, and a seed.

20. The method according to claim 20 or 19 wherein the active agent is a granule having a diameter of between 0.5-4 mm.

21. The method according to any one of claims 18-20 further comprising adding a mineral filler to the Portland cement.

22. The method according to any one of claims 18-21 wherein the active agent is added in an amount of between 9.5: 0.5 and 6:4 relative to the weight of the Portland cement, liquid fatty acid composition, and mineral filler.

23. The method according to any one of claims 18-22 wherein the ratio of fatty acid to Portland cement and mineral filler is between 3:17 and 9:11.

24. The method according to any one of claims 18-23, wherein contacting is performed in a rotating apparatus.

25. The method according to any one of claims 18-24, wherein the coating hardens within 10 minutes from contacting of step a.

26. The method according to any one of claims 18-24, wherein the steps a and b are performed at room temperature.

27. The method according to any one of claims 18-26 wherein after hardening of the coating, a further layer of coating is formed by repeating steps a. and b.

28. The method according to claim 26 wherein steps a. and b. are repeated 2-times.

29. A composition according to any one of claims 1-17 and free of plastic. 313232/

30. A composition according to any one of claims 1-17 for use in agriculture.

31. The composition according to any one of claims 1-5 or 8-17 for use in enhancing growth of a crop.

32. The composition according to claim 31, wherein upon contact with water maintained at 25°C ±2°C, at a ratio by weight of 1 part coated active agent to 10 parts water, the composition loses less than 50% of its weight over the first 24 hours.

33. The composition according to claim 32, wherein upon contact with water maintained at 25°C ±2°C, at a ratio by weight of 1 part coated active agent to 10 parts water, the composition loses less than 15% of its weight over the first 24 hours.

34. The composition according to any one of claims 1 or 6-17 for use in enhancing growth of an animal.

35. A product manufactured according to the method of any one of claims 18-28.