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WO2018058195A1 - Procédé de production de granulés pour l'administration contrôlée d'un principe actif - Google Patents

Procédé de production de granulés pour l'administration contrôlée d'un principe actif Download PDF

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Publication number
WO2018058195A1
WO2018058195A1 PCT/AU2017/051067 AU2017051067W WO2018058195A1 WO 2018058195 A1 WO2018058195 A1 WO 2018058195A1 AU 2017051067 W AU2017051067 W AU 2017051067W WO 2018058195 A1 WO2018058195 A1 WO 2018058195A1
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WO
WIPO (PCT)
Prior art keywords
polymer
poly
tube
process according
core matrix
Prior art date
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Ceased
Application number
PCT/AU2017/051067
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English (en)
Inventor
Nicholas EBDON
Raju Adhikari
Michael Shane O'shea
Gary Peeters
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Commonwealth Scientific and Industrial Research Organization CSIRO
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Commonwealth Scientific and Industrial Research Organization CSIRO
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Publication date
Priority claimed from AU2016903962A external-priority patent/AU2016903962A0/en
Application filed by Commonwealth Scientific and Industrial Research Organization CSIRO filed Critical Commonwealth Scientific and Industrial Research Organization CSIRO
Publication of WO2018058195A1 publication Critical patent/WO2018058195A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C05—FERTILISERS; MANUFACTURE THEREOF
    • C05C—NITROGENOUS FERTILISERS
    • C05C1/00—Ammonium nitrate fertilisers
    • C05C1/02—Granulation; Pelletisation; Stabilisation; Colouring
    • C—CHEMISTRY; METALLURGY
    • C05—FERTILISERS; MANUFACTURE THEREOF
    • C05C—NITROGENOUS FERTILISERS
    • C05C3/00—Fertilisers containing other salts of ammonia or ammonia itself, e.g. gas liquor
    • C05C3/005—Post-treatment
    • C—CHEMISTRY; METALLURGY
    • C05—FERTILISERS; MANUFACTURE THEREOF
    • C05C—NITROGENOUS FERTILISERS
    • C05C9/00—Fertilisers containing urea or urea compounds
    • C—CHEMISTRY; METALLURGY
    • C05—FERTILISERS; MANUFACTURE THEREOF
    • C05C—NITROGENOUS FERTILISERS
    • C05C9/00—Fertilisers containing urea or urea compounds
    • C05C9/005—Post-treatment
    • C—CHEMISTRY; METALLURGY
    • C05—FERTILISERS; MANUFACTURE THEREOF
    • C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
    • C05G3/00—Mixtures of one or more fertilisers with additives not having a specially fertilising activity
    • C—CHEMISTRY; METALLURGY
    • C05—FERTILISERS; MANUFACTURE THEREOF
    • C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
    • C05G5/00—Fertilisers characterised by their form
    • C05G5/10—Solid or semi-solid fertilisers, e.g. powders
    • C05G5/14—Tablets, spikes, rods, blocks or balls
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/08—Processes
    • C08G18/0804—Manufacture of polymers containing ionic or ionogenic groups
    • C08G18/0819—Manufacture of polymers containing ionic or ionogenic groups containing anionic or anionogenic groups
    • C08G18/0823—Manufacture of polymers containing ionic or ionogenic groups containing anionic or anionogenic groups containing carboxylate salt groups or groups forming them
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/08—Processes
    • C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/30—Low-molecular-weight compounds
    • C08G18/34—Carboxylic acids; Esters thereof with monohydroxyl compounds
    • C08G18/348—Hydroxycarboxylic acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
    • C08G18/4266—Polycondensates having carboxylic or carbonic ester groups in the main chain prepared from hydroxycarboxylic acids and/or lactones
    • C08G18/4269—Lactones
    • C08G18/4277—Caprolactone and/or substituted caprolactone
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
    • C08G18/66—Compounds of groups C08G18/42, C08G18/48, or C08G18/52
    • C08G18/6633—Compounds of group C08G18/42
    • C08G18/6659—Compounds of group C08G18/42 with compounds of group C08G18/34
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
    • C09D175/04—Polyurethanes
    • C09D175/06—Polyurethanes from polyesters
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G2230/00—Compositions for preparing biodegradable polymers

Definitions

  • the invention relates to a process for preparing pellets for controlled release of an active and to pellets produced by the process.
  • the invention relates to a process for preparation of pellets for controlled release of agrichemicals and agrichemical products.
  • agrichemicals such as fertilizers, soil conditioners, fungicides, insecticides, herbicides, nematocides, plant hormones, insect repellents, and the like, in order to control their release over varying periods of time after they have been applied.
  • Controlled release products have been prepared which attempt to deliver agrichemicals to plants at a time period in their development when the agrichemicals provide the most desirable benefits. To a large extent, these products are made by coating fertilizer granules or prills with various materials to reduce the rate of release of the fertilizing agent.
  • U.S. Pat. No. 3,223,518 issued to Hansen Dec. 14, 1965 discloses coatings of polymer resins exemplified by linseed oil- or soybean oil-based resins, e.g. linseed oil- based copolymers with dicyclopentadiene.
  • the release rates of the coated products described in the '518 patent depend on various factors, some of which include the number of coatings applied to the product, or the coating's thicknesses, and the type of polymer used in the coating. In such fertilisers the onset of release occurs almost immediately upon application of the fertilizer product and typically within a week of being applied.
  • a fertilizer product exemplifying this type of controlled release is available as Osmocote ® fertilizer.
  • Water-insolubility of the coating resin such as polyethylene, polypropylene and copolymers thereof have been investigated.
  • US Patent 4369055 describes fertilizer with a controlled permeability coating which comprises a polyolefin coating which is prepared by spraying a hot solution of polyolefin type resin, ethylene-vinyl acetate copolymer or vinylidene type resin upon fertilizer granules, and drying the fertilizer granules. Such coatings will not
  • EP0828527 discloses a delayed, controlled release product comprising: (a) a core comprising a water soluble active ingredient; (b) a first coating layer on the surface of the core (a), wherein said layer has the ability to release the active ingredient at a controlled rate; and (c) a second coating layer encapsulating (a) application of coatings tends to require significant thicknesses to avoid breaches which can lead to rapid loss of the agrichemical or a number of different coatings to ensure maintenance of an effective barrier to agrichemical release for the required delay period.
  • the process comprises: providing a core matrix comprising a mixture of urea, a silicate mineral and a biodegradable polyurethane polymer;
  • the core matrix is prepared by combining a urea composition, silicate mineral and biodegradable polyurethane polymer in an aqueous composition; mixing the composition; and forming the composition into an extrudable form.
  • the step of forming the matrix into an extrudable form may comprise changing the consistency by removing water or adding components such as thickeners to provide a suitable consistency for extrusion.
  • pelletised fertiliser composition for delayed release of the fertiliser, comprising an extruded coating of biodegradable polyester polymer and a core matrix comprising a mixture of a nitrogenous fertiliser and a silicate mineral.
  • the core matrix comprises an intimate mixture comprising: from 20% to 70% w/w (preferably 30% to 65% w/w) of nitrogenous fertiliser; from 10 % to 60% w/w (preferably 10% to 30% w/w) of silicate mineral; and from 5% to 60% w/w (preferably 10% to 30% w/w) biodegradable polyurethane; wherein the weights are based on dry weight of the core matrix composition.
  • the preferred active is an agrichemical active.
  • agrichemical and “agrichemicals”, refer to a wide range of active materials used in agriculture such a fertilizers, soil conditioners, fungicides, insecticides, herbicides, nematocides, plant hormones, insect repellents, and the like.
  • the granules of the composition may include a fertiliser.
  • fertiliser refers to material of natural or synthetic origin that is applied to soils to supply one or more plant nutrients essential to the growth of plants.
  • the fertiliser may provide a source of one or more of nitrogen, phosphorus, potassium, calcium, magnesium and sulfur. Specific examples of fertilisers may be selected from the group consisting of urea, ammonium nitrate, potassium nitrate, ammonium sulfate, potassium sulfate, potassium chloride, mono ammonium phosphate (MAP),
  • diammonium phosphate DAP and mixtures of two or more thereof.
  • Fertilisers providing at least one or more of nitrogen, phosphorus and potassium are preferred and nitrogen based fertilisers are particularly useful in the granular composition, optionally in combination with one or more of phosphorus, potassium, calcium, magnesium and sulfur.
  • the more preferred nitrogen based fertilisers are urea and nitrates such as calcium nitrate and ammonium nitrate.
  • Fertilisers based on urea optionally in combination with a nitrate such as ammonium nitrate and/or calcium nitrate are particularly preferred.
  • molecular weight (Mn) or Mn refers to the number average molecular weight and the term molecular weight (Mp) or Mp refers to the mode of the molecular weight distribution or molecular weight of the highest peak.
  • plants refers to all physical parts of plants including seeds, seedlings, saplings, roots, tubes and material from which plants may be propagated.
  • granule means a capsule, a pellet, a pill or a bead.
  • pellet means a rounded body (e.g. spherical, cylindrical). The terms pellets and granules are generally used interchangeably herein.
  • pellets and granules in accordance with the invention have a maximum dimension in the range of from 1 mm to 20 mm, such as 1 mm to 8 mm, 3 mm to 20 mm or 5 mm to 20 mm.
  • the pellets are cylindrical and have an aspect ratio (length to width) of from 1 to10, preferably from 1 to 5.
  • biodegradable is art-recognized, and includes polymers
  • compositions and formulations such as those described herein, that are intended to degrade during use by biological means such as bacteria and fungi in addition to degradation by other chemical processes such as hydrolytic, oxidative and enzymatic processes.
  • biological means such as bacteria and fungi
  • other chemical processes such as hydrolytic, oxidative and enzymatic processes.
  • degradation to produce release of the active and regulate release of the active In general, degradation attributable to biodegradability involves the degradation of a biodegradable polymer into its component sub units monomers and oligomers, and eventually into nontoxic by products.
  • reactive extrusion refers to the performance of chemical reactions during continuous extrusion of polymers and/or polymerizable monomers.
  • the reactants must be in a physical form suitable for extrusion processing. Reactions may be performed on molten polymers, on liquified monomers, or on polymers dissolved or suspended in or plasticized by solvent.
  • Reactive extrusion refers to the performance of chemical reactions in a continuous extrusion process with short residence times. Detailed teachings relating to reactive extrusion are, for example, provided in "Reactive Extrusion - Principles and Practice" edited by M. Xanthos, Carl Hanser Verlag, Kunststoff, Vienna, New York, Barcelona, 1992.
  • the process for preparing pellets comprises:
  • the extrusion of the tube may use conventional extrusion equipment.
  • the core matrix is intermittently inserted into the tube during the process of extrusion of the tube. For example, in one set of
  • the core matrix is intermittently extruded within the tube.
  • the equipment used may be any suitable equipment known in the art for coextrusion.
  • the appropriate condition for extrusion will depend on the consistency and composition of the core matrix.
  • the core matrix is of a paste consistency which may be readily extruded.
  • the core matrix comprises a polymeric material which may be a thermoplastic or thermoset and facilitate coextrusion.
  • the process of sealing the tube may be carried out in a number of ways.
  • the step of sealing the tube comprises collapsing the tube between portions of core matrix.
  • the collapsing process may be carried out by one or more blades applying pressure to the side of the tube while in a relatively plastic state.
  • a plurality of opposed blades may apply a force to the outside of the tube to collapse it between portions of core matrix.
  • This step may produce separation of individual pellets or separation may be carried at a later step or even by the end user.
  • the process comprises intermittently inserting portions of a barrier resin material such as a wax, polymer or the like between portions of matrix and cutting through the tube and barrier material between portions of core matrix.
  • a barrier resin material such as a wax, polymer or the like between portions of matrix and cutting through the tube and barrier material between portions of core matrix.
  • the resulting pellets have a peripheral wall of tube polymer and end walls of barrier material with the core matrix portions encased within.
  • the tube in this embodiment may form a seal with the resin.
  • the resin used in forming the ends of the pellets may be the same or different from the tube polymer. For example a different porosity or biodegradability of the resin compared with the polymer tube may be used to control the delay in exposure of the core matrix to the environment in use, such as when placed in soil.
  • the process comprises: providing a core matrix comprising a mixture of urea, a silicate mineral and a biodegradable polyurethane polymer; • extruding a tube of polymer biodegradable polymer;
  • the extruded tube portion of the pellets is prepared by extrusion of a suitable barrier material.
  • the tube is formed of a biodegradable polymer selected from synthetic biodegradable polymers and natural biodegradable polymers.
  • the tube may be formed of a thermoplastic or thermoset polymer.
  • Synthetic biodegradable polymers include polyesters, such as for example, poly(lactic acid), poly(glycolic acid), copolymers of lactic and glycolic acid, copolymers of lactic and glycolic acid with poly(ethylene glycol), poly(e-caprolactone), poly(3-hydroxybutyrate), poly(p-dioxanone), polypropylene fumarate); Poly (ortho esters) including Polyol/diketene acetals addition polymers as described by Heller in: ACS Symposium Series 567, 292- 305, 1994; Polyanhydrides including po!y(sebacic anhydride) (PSA), poly(carboxybisbarboxyphenoxyphenoxyhexane) (PCPP), poly[bis (p- carb
  • Natural Polymers may be used, such as carbohydrates, polypeptides and proteins including: Starch, Cellulose and derivatives including ethylcellulose, methylcellulose, ethylhydroxyethylcellulose, sodium carboxymethylcellulose; Collagen; Gelatin; Dextran and derivatives; Alginates; Chitin; and Chitosan;
  • a non biodegradable polymer if used, is selected from polymers such as ester urethanes or epoxy, bis-maleimides, methacrylates such as methyl or glycidyl methacrylate, tri- methylene carbonate, di-methylene carbonate and dimethyl tri- methylene carbonate; and where used, biodegradable synthetic polymers such as glycolic acid, glycolide, lactic acid, lactide, p-dioxanone, dioxepanone, alkylene oxalates and caprolactones such as gamma-caprolactone are preferred.
  • the polymer may comprise any one or a
  • the preferred biodegradable polymers are polyesters, particularly aliphatic polyesters.
  • polyesters include for example, poly(lactic acid), poly(glycolic acid), copolymers of lactic and glycolic acid, copolymers of lactic and glycolic acid with poly(ethylene glycol), poly(e-caprolactone), poly(3-hydroxybutyrate), poly(p-dioxanone), polypropylene fumarate); poly (ortho esters) including
  • polyanhydrides including po!y(sebacic anhydride) (PSA), poly[bis(p-carboxyphenoxy)propane)anhydride](PCPP), poly[bis (p- carboxyphenoxy) methane] (PCPM), poly[bis(carboxyphenoxy)hexane]copolymers of SA, CPP and CPM, such as described by Tamada and Langer in Journal of
  • PSA po!y(sebacic anhydride)
  • PCPP poly[bis(p-carboxyphenoxy)propane)anhydride]
  • PCPM poly[bis (p- carboxyphenoxy) methane]
  • SA po!y(sebacic anhydride)
  • PCPP poly[bis(p-carboxyphenoxy)propane)anhydride]
  • PCPM poly[bis (p- carboxyphenoxy) methane]
  • PCPM poly[bis(carboxyphenoxy)hexane]copolymers of SA, CPP and CPM
  • the tube comprises a polymer having at least a polymeric segment selected from the group consisting of polylactic acid (PLA), poly(glycolic acid), polycaprolactone (PCL), polyvalerolactone, poly(hydroxyl valerate), poly(ethylene succinate), poly(butylene succinate), poly(butylenesuccinateadipate), poly(para-dioxanone), polydecalactone, poly(4-hydroxybutyrate), poly(beta-malic acid) and poly(hydroxyl valerate).
  • the polymer may be a polyurethane or polyurea comprising such groups or in a preferred set of embodiments comprises the aliphatic polyester polymer or blend of such polymers.
  • biodegradable polymer is a
  • caprolactone polymer which may be a homopolymer of caprolactone or a copolymer such as a block copolymer of poly(l-lactic acid) and poly ⁇ -caprolactone.
  • the polymer tube may be formed from corresponding poly(ester- urethane)s such as a polyurethane comprising polyester diols such as the
  • the biodegradable polymer is a polycaprolactone or caprolactone copolymer, particularly a polycaprolactone polylactic acid block copolymer, which is prepared by reactive extrusion in the process of forming the polymer tube.
  • the polymer tube is preferably formed of biodegradable polyester polymer having a molecular weight (Mn) of at least 20,000, preferably at least 30,000 and most preferably at least 50,000.
  • Polycaprolatone homopolymers and copolymers, such as with an acid monomer, particularly poly-L-lactic acid, having a molecular weight (Mn) of at least 20,000, preferably at least 30,000 and most preferably at least 50,000 are most preferred.
  • the tube is formed of a polymer selected from the group consisting of polylactic acid, poly(glycolic acid),
  • polycaprolactone polyvalerolactone, poly(hydroxyl valerate), poly(ethylene succinate), poly(butylene succinate), poly(butylenesuccinateadipate), poly(para-dioxanone), polydecalactone, poly(4-hydroxybutyrate), poly(beta-malic acid), poly(hydroxyl valerate), polycaprolactone copolymers with polylactic acid and mixtures of two or more of these polymers.
  • the tube is preferably extruded to provide a tube wall thickness of no more than 500 microns, preferably no more than 300 microns.
  • the tube wall is at least 10 microns, such as from 10 to 300 microns, 10 to 100 microns or 20 to 70 microns. The more preferred range of wall thickness to achieve delayed release with
  • biodegradable polyesters such as PCL and PCL-PLA is typically in the range of from 20 microns to 200 microns but will depend on the specific polymer composition and molecular weight of the components.
  • Such polymers may be prepared by ring opening polymerisation in a reactive extrusion process.
  • the inside diameter of the tube (generally corresponding with the matrix diameter) is preferably in the range of from 1 mm to 9.5 mm.
  • a Lewis acid catalyst may be used to control the rate of degradation of a biodegradable polymer such as PCL or PCL-PLA. It is known to use metal and non-metal catalysts in preparation of polycaprolactone and other polyester biodegradable polymers. We have found, however, that the level of Lewis acid catalyst has a significant effect on the rate of degradation of the polymer coating or tube and that this finding can be used to control the rate of release of the fertiliser when placed in soil. Accordingly the process preferably comprises extruding the tube of biodegradable polymer wherein the biodegradable polymer comprises a Lewis acid in an amount sufficient to enhance the degradation of the polymer.
  • the amount of Lewis acid may be determined having regard to the delay required prior to release of the agrochemical active.
  • the biodegradable polymer is selected from aliphatic polyester, polycarbonate and polyanhydrides.
  • the amount of Lewis acid catalyst is preferably at least 0.05 % (such as 0.05% to 1 % or 0.05% to 0.5%) by weight based on the weight of
  • biodegradablepolymer preferably at least 0.05% by weight and more preferably at least 0.1 % w/w, more preferably in the rage of from 0.1 % to 1 % by weight based on the weight of biodegradable polymer and more preferably from 0.1 % to 0.5 % by weight based on the weight of biodegradable polymer.
  • suitable Lewis acid catalysts include those based on metals selected from Cu 2+ , Zn 2+ , Mg 2+ , Ti 2+ and the like which may be in the form of simple salts such as sulfates or chlorides or organometalics such as aluminium isopropoxide, titanium tetrabutoxide, tin octanoate.
  • Preferred Lewis acids may be selected from the group consisting of titanium dioxide, titanium chloride, aluminium isopropoxide, aluminium halide, tin dioxide and
  • the tube may be formed of a polymer composition comprising one or more filler materials which may be used to modify the rate of degradation of the pellets by providing pores or greater water permeability to provide access of water from the soil to the core matrix following placement of the pellet in soil.
  • fillers include mineral and organic fillers (e.g., talc, mica, clay, silica, alumina, carbon fiber, carbon black and glass fiber) and conventional cellulosic materials (e.g., wood flour, wood fibers, sawdust, wood shavings, newsprint, paper, flax, hemp, wheat straw, rice hulls, kenaf, jute, sisal, peanut shells, soy hulls, or any cellulose containing material).
  • the amount of filler in the melt processable composition may vary depending upon the polymeric matrix and the desired physical properties of the finished
  • the process comprises inserting within the tube a plurality of longitudinally spaced portions of a core matrix comprising the active.
  • the matrix comprises the active agent which may be selected from a range of bioactive materials.
  • the bioactive agent is an agrichemical selected from the group consisting of fertilisers, pesticides such as one or more of herbicides, insecticides and fungicides, and plant growth regulators.
  • the active is a water soluble fertiliser.
  • fertilisers may be selected from the group consisting of urea, ammonium nitrate, potassium nitrate, ammonium sulfate, potassium sulfate, potassium chloride, mono ammonium phosphate (MAP), diammonium phosphate (DAP) and mixtures of two or more thereof.
  • More preferred actives are water soluble nitrogenous fertiliser, most preferably urea, urea ammonium nitrate, urea calcium nitrate or mixture thereof.
  • the fertiliser further comprises one or further actives such as at least one of a potassium and phosphorus fertiliser component.
  • the fertiliser further comprises one or further actives such as at least one of a potassium and phosphorus fertiliser component.
  • composition comprises nitrogenous, potassium and phosphorus fertiliser components providing a suitable NPK balanced fertiliser.
  • the urea may be used in the form of an aqueous slurry which may be absorbed onto a solid carrier such as a inorganic silicate which may, for example, be selected from the group consisting of attapulgite, kaolin, diatomaceous earth, bentonite, zeolite, mica, talc and mixtures thereof.
  • a solid carrier such as a inorganic silicate which may, for example, be selected from the group consisting of attapulgite, kaolin, diatomaceous earth, bentonite, zeolite, mica, talc and mixtures thereof.
  • the preferred carrier is selected from the group consisting of clay, more preferably a clay selected from the group consisting of montmorillonite, bentonite and attapulgite.
  • the process comprises:
  • the core matrix comprises a mixture of fertiliser composition comprising a urea, urea ammonium nitrate, urea calcium nitrate or mixture composition and a solid particulate carrier, preferably a clay and a biodegradable polymer matrix.
  • the matrix composition in a preferred set of embodiments is prepared by combining nitrogen fertiliser, particularly an aqueous liquid urea with a particulate carrier such as a clay and a biodegradable polymer dispersion (and optionally at least partly drying the composition) to provide a matrix composition which is flowable under the conditions under which the plurality of longitudinally spaced portions of the core matrix comprising the active are inserted within the polymer tube.
  • nitrogen fertiliser particularly an aqueous liquid urea
  • a particulate carrier such as a clay
  • a biodegradable polymer dispersion and optionally at least partly drying the composition
  • the presence of the solid particulate, particularly a clay provides control over release of the nitrogen fertiliser in the pellet composition. This allows a gradual release of fertiliser once the polymer tube has been lost in the soil due to erosion or dissolution of the coating.
  • the presence of the biodegradable polymer distributed in the core matrix, particularly a biodegradable polyurethane polymer, in combination with the polymer tube provides a significant delay in release of the fertiliser once the product has been placed in contact with soil or moisture.
  • the process of the invention allows preparation of pellets in which the release of fertiliser following placement of the pellets is delayed for a period. This delay period is particularly advantageous where fertiliser is placed during placement of plants such as seed, seedlings or transplanted plants which have progressed beyond the seedling stage.
  • the process provides pellets which have a period of delay of at least 7 days, preferably at least 14 days. The delay in commencement of release allows establishment of the plant prior to release and avoids the harm which results from heavy doses of fertilizer.
  • the composition prepared by the process allows the most economic use of fertiliser by allowing controlled release of the fertiliser when it is most productively used by plants to induce growth and/or crop production.
  • the core matrix composition comprises an intimate mixture comprising: from 20% to 70% (preferably 30% to 65% w/w) of nitrogenous fertiliser; from 10% to 60% w/w (preferably 10% to 30% w/w)of silicate mineral; and from 5 % to 60% w/w (preferably 5% to 30% w/w) biodegradable polymer, preferably polyurethane; wherein the weights are based on dry weight of the core matrix composition.
  • the matrix may comprise water to provide a paste consistency typically the matrix will comprise up to 20% by weight water based on the weight of nitrogenous fertiliser component.
  • the core matrix composition preferably comprises a biodegradable polymer which is preferably a biodegradable polyurethane.
  • a biodegradable polymer which is preferably a biodegradable polyurethane.
  • biodegradable polyurethane polymer may be used in the form of an aqueous
  • aqueous slurry of the composition which may optionally be dried, to provide a composition of suitable consistency to allow introduction of the core matrix into the polymer tube under the conditions to be used.
  • the matrix polymer is a biodegradable polyurethane disclosed in International Publication WO 2015/184490.
  • the core matrix comprise a polyurethane comprising a biodegradable polyester polyol.
  • the polyester polyols are esterification products prepared by the reaction of organic polycarboxylic acids or their anhydrides with a stoichiometric excess of a polyol.
  • suitable polyols for use in the reaction include polylactic acid polyol, polyglycolic polyol, polyglycol adipates, polyethylene terepthalate polyols, polycaprolactone polyols, orthophthalic polyols, and sulfonated polyols, etc.
  • the polycarboxylic acids and polyols are typically aliphatic or aromatic dibasic acids and diols.
  • the diols used in making the polyester include alkylene glycols, e.g., ethylene glycol, butylene glycol, neopentyl glycol and other glycols such as bisphenol A, cyclohexane diol, cyclohexane dimethanol, caprolactone diol, hydroxyalkylated bisphenols, and polyether glycols.
  • alkylene glycols e.g., ethylene glycol, butylene glycol, neopentyl glycol and other glycols such as bisphenol A, cyclohexane diol, cyclohexane dimethanol, caprolactone diol, hydroxyalkylated bisphenols, and polyether glycols.
  • alkylene glycols e.g., ethylene glycol, butylene glycol, neopentyl glycol and other glycols such as bisphenol A, cyclohexane diol, cyclohexan
  • polyurethane in one set of embodiments comprises one or more polyester monomer segments selected from the group consisting of polylactic acid, poly(glycolic acid), polycaprolactone, polyvalerolactone, poly(hydroxyl valerate), poly(ethylene succinate), poly(butylene succinate), poly(butylenesuccinateadipate), poly(para-dioxanone), polydecalactone, poly(4-hydroxybutyrate), poly(beta-malic acid) and poly(hydroxyl valerate).
  • polyester monomer segments selected from the group consisting of polylactic acid, poly(glycolic acid), polycaprolactone, polyvalerolactone, poly(hydroxyl valerate), poly(ethylene succinate), poly(butylene succinate), poly(butylenesuccinateadipate), poly(para-dioxanone), polydecalactone, poly(4-hydroxybutyrate), poly(beta-malic acid) and poly(hydroxyl valerate).
  • the polyols are functionalised products prepared by the hydroxylation of vegetable oils such as castor soyabean and linoleic acid.
  • the polyurethane comprises a polyester segment selected from polycaprolactone, polylactic acid and a mixture thereof or copolymer thereof.
  • An aqueous dispersion of polyurethane for mixing with the other core matrix components may be prepared by reacting a diisocyanate with an active hydrogen containing monomer such as dihydroxy polyol to form an isocyanate terminated prepolymer.
  • the active hydrogen containing monomer may comprise of ionic or ionisable pendent groups or the isocyanate capped prepolymer may be reacted with a chain extender to provide ionic or ionisable groups.
  • the prepolymer is chain extended with a polyol, polyamide, polyamine or mixture thereof which may comprise ionic or ionisable pendent groups.
  • the prepolymer is chain extended with a primary or secondary amine having at least two active hydrogens and which may be quaternized to provide cationic groups.
  • Suitable aliphatic polyisocyanates include those selected from the group consisting of hexamethylene 1 ,6-diisocyanate, 1 ,12-dodecane diisocyanate, 2,2,4- trimethyl-hexamethylene diisocyanate, 2,4,4-trimethyl- hexamethylene diisocyanate, 2-methyl-l,5-pentamethylene diisocyanate, alkyl- lysinediisocyanate (such as ethyl-lysine diisocyanate and mixtures thereof).
  • Suitable cycloalipahtic polyisocyanates include dicyclohexlymethane diisocyanate, isophorone diisocyanate, 1 ,4-cyclohexane diisocyanate, 1 ,4- cyclohexane bis(methylene isocyanate), 1 ,3- bis(isocyanatomethyl) cyclohexane, and mixtures thereof.
  • isophorone diisocyanate or cyclohexane bis(methylene isocyanate) to be particularly useful in providing the desired properties of biodegradability and membrane formation properties to match the growing season of the crop.
  • the polyurethane is an ionic polyurethane comprising ionic groups selected from the group consisting of
  • the matrix preferably comprises a polyurethane which is a reaction product of (a) a diisocyanate; and (b) at least one active hydrogen containing compounds and wherein at least one active hydrogen containing compound comprises an ionic or ionisable group which provide ionic groups on neutralisation.
  • the polyurethane preferably comprises a polyol prepolymer particularly a polyester polyol prepolymer which confers biodegradability on the polyurethane and which has a molecular weight of 500-5000, preferably 500-2000.
  • the polyurethane polymer is chain extended with a primary or secondary amine having at least two active hydrogens and which may be quaternised to provide cationic groups.
  • the polyurethane comprises a plurality of ionic groups derived from monomers independently selected from the group consisting of
  • Ri is an alkyl group of 1 to 4 carbons
  • R 2 and R 3 are independently selected from the group consisting of alkyl groups of 1 to 4 carbon atoms; aryl; aralkyl; polyester and polyether moieties;
  • R 4 is -O or -NH, where the bond - denotes the point of attachment to the polymer backbone or terminal functional groups of the polymer;
  • R 5 is selected from the group consisting of hydrogen, alkyl groups of 1 to 18 carbon atoms; aryl groups; aralkyl groups;
  • R6 is selected from the group consisting of carboxylates, sulfonates and phosphonates.
  • Ei is a counter-ion that is organic or inorganic; and E 2 is a counter-ion that is organic or inorganic.
  • the ionic groups may, for example be provided by one or more monomers selected from the group consisting of 2,2- bis(hydroxymethyl) propionic acid (BMPA), tartaric acid, dimethylol butanoic acid (DMBA), glycollic acid, thioglycollic acid, lactic acid, malic acid, dihydroxy malic acid, dihydroxy tartaric acid, and 2,6-dihydroxy benzoic acid and neutralisation of the resulting polymer with a tertiary amine.
  • BMPA 2,2- bis(hydroxymethyl) propionic acid
  • DMBA dimethylol butanoic acid
  • glycollic acid glycollic acid
  • thioglycollic acid glycollic acid
  • lactic acid malic acid, dihydroxy malic acid, dihydroxy tartaric acid
  • 2,6-dihydroxy benzoic acid 2,6-dihydroxy benzoic acid and neutralisation of the resulting polymer with a tertiary amine.
  • the polyurethane comprises aliphatic polyester diol segments such as polycaprolactone diol segments and a plurality of the ionic groups.
  • a controlled release granular fertiliser may comprise a polyurethane which is cross linked by a cross linker selected from the group consisting of divalent and trivalent metal cations.
  • the nitrogenous fertiliser is at least 30% by weight of the controlled release fertiliser wherein the weights are based on dry weight.
  • Ionic groups are preferably incorporated into the polyurethane to provide a stable water based dispersion. This allows the use of organic solvents to be minimised and assists in providing a resilient membrane on application to soil materials.
  • the acid ionisable groups are generally incorporated in the polymer or prepolymer in an inactive form and activated by a salt-forming compound such as a tertiary amine.
  • Suitable tertiary amines which can be used to neutralize the polymer include organic tertiary amine bases such as triethyl amine (TEA), N-methyl morpholine and inorganic bases sodium hydroxide or ammonia.
  • TAA triethyl amine
  • the preferred tertiary amine is triethyl amine (TEA). It is recognized that primary or secondary amines may be used in place of tertiary amines, if they are sufficiently hindered to avoid interfering with the chain extension process.
  • Aqueous dispersions of cationic polyurethane polymers may be prepared using chain extenders which comprise of secondary amines.
  • chain extenders which comprise of secondary amines.
  • N-alkyl dialkanolamine such as N-methyl diethanolamine (MDEA) may be used as a chain extender and then the product quaternised by reacting with a quaternising agent.
  • MDEA N-methyl diethanolamine
  • Cationic polyurethanes may also be prepared having tertiary amine groups tethered to the polyurethane backbone.
  • Such cationic polyurethanes may be prepared from polyols substituted with side chains comprising a tertiary amine group which may be quaternised and neutralised with an organic acid such as formic acid, acetic acid, propionic acid, succinic acid, glutaric acid, butyric acid, lactic acid, malic acid, citric acid, tartaric acid, malonic acid and adipic acid; organic sulfonic acids such as sulfonic acid, paratoluene sulfonic acid and methanesulfonic acid; inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, phosphorous acid and fluoric acid. Examples of polyurethanes having tethered cationic groups are disclosed in WO2012/058534, US2008/00
  • chain extension may be achieved using one or more polyamines.
  • Organic compounds having two or more primary and/or secondary amine groups may be used. Suitable organic amines for use as a chain extender include di-ethylene tri- amine (DETA), ethylene diamine (EDA), meta-xylylene diamine (MXDA), and aminoethyl ethanolamine (AEEA).
  • DETA di-ethylene tri- amine
  • EDA ethylene diamine
  • MXDA meta-xylylene diamine
  • AEEA aminoethyl ethanolamine
  • propylene diamine butylene diamine, hexamethylene diamine, cyclohexylene diamine, phenylene diamine, tolylene diamine, xylene diamine, 3,3-dichlorobenzidene, 4,4-methylene-bis (2-chloroaniline), and 3,3-dichloro-4,4-diamino diphenylmethane.
  • the biodegradable polymer tube comprises at least one polyester selected from the group consisting of polylactic acid, poly(glycolic acid), polycaprolactone, polyvalerolactone, poly(hydroxyl valerate), poly(ethylene succinate), poly(butylene succinate), poly(butylenesuccinateadipate), poly(para-dioxanone), polydecalactone, poly(4-hydroxybutyrate), poly(beta-malic acid) poly(hydroxyl valerate) and copolymers thereof, more preferably the extruded tube is formed of a polyester selected from the group consisting of polylactic acid, poly(glycolic acid), polycaprolactone, polyvalerolactone, poly(hydroxyl valerate), poly(ethylene succinate), poly(butylene succinate), poly(butylenesuccinateadipate), poly(para-dioxanone), polydecalactone, poly(4-hydroxybutyrate), poly(beta-malic acid) poly(hydroxyl valerate
  • the molecular weight (Mn) of the polymer coating is at least 20,000, more preferably at least 50,000; and the core matrix comprises a mixture of urea, a silicate mineral which is a clay and a matrix polymer which is a biodegradable polyurethane comprising polyester diol segments such as polycaprolactone diol and ionic groups such as BMPA.
  • the weight (dry weight basis) ratio of silicate mineral to nitrogenous fertiliser is preferably in the range of from 1 :5 to 5:1 , more preferably 1 :2 to 2:1 .
  • the extruded tube of biodegradable polymer preferably comprises from 1 % to 10% by weight of the weight of the pellet.
  • Figure 1 is a graph showing the degradation profile, presented as GPC
  • FIG. 1 is a graph showing the influence of humidity level applied using a controlled chamber on the molecular weight (Mp) of compositions of Example 1 with differing amounts of catalyst in accordance with the test protocol of Example 3.
  • Figure 3 includes two column charts (3a and 3b) showing the molecular weight (Mn in left column Mw in right hand column) for PLA-PCL films with different amounts of catalyst after exposure for one month ( Figure 3a) and two months ( Figure 3b) in accordance with the testing protocol described in Example 4.
  • Figure 4 includes two column charts (4a and 4b) showing the effect of different Lewis acid catalysts on the hydrolytic degradation of films of PCL-PLLA after 44 days in accordance with Example 5.
  • Figure 4a showing molecular weight
  • Figure 4b showing polydispersity against a polystyrene standard.
  • Figure 5 includes two column charts (5a and 5b) showing the affect of different amounts of the Lewis acid aluminium isopropoxide on the hydrolytic degradation of films of PCL-PLLA after 44 days in accordance with Example 6.
  • Figure 6 shows the testing assembly used to assess urea release from extruded biodegradable polymer containing different Lewis acid catalyst loadings.
  • Figure 7 is a graph showing the urea transport across a range of membranes compositions of thickness 120 microns at 22 ⁇ C, 35*0 and 50 ⁇ C.
  • Figure 8 is a graph showing the variation of urea transport with time across a 160 micron membrane of a composition containing 70%PLLA 30% PCL with 0.5 % w/w catalyst (three left hand side plots) and without catalyst (three right hand side plots).
  • Figure 9 is a graph of variation of urea transport across polymer membranes with time for three membranes with 70PLLA30PLC of 1 60 micron thickness and no catalyst (upper three plots) and 70PLLA30PCL with 200 micron thickness (lower two plots).
  • Figure 10 is a schematic longitudinal section showing an extruder for coextrusion of nutrient matrix within a continuous polymer tube.
  • Figure 11 shows a schematic longitudinal section showing intermediates in preparing pellets of one embodiment of Figure 1 1 including (a) the tube containing spaced nutrient matrix segments, (b) segment of tube cut between discrete nutrient matrix portions and (c) completed pellets in which ends of cut tube segments are closed so that the tube polymer envelops the nutrient matrix.
  • Figure 12 is a longitudinal cross section of one embodiment of a pellet formed in accordance with the invention.
  • Figure 13 shows a schematic longitudinal section showing intermediates in preparation of pellets of an alternative process in which alternating polymer and nutrient matrix portions are coextruded within the tube (a) and tube is cut between spaced nutrient portions and through polymer portions to provide a tube of polymer having and outer tube, central nutrient matrix within the tube and ends of the tube sealed with polymer (b).
  • Figure 14 is a graph showing the percentage of urea lost with time from urea prills coated with PCL as described in Example 13.
  • Figure 15 includes two graphs showing the change in molecular weight of PCL- PLLA films containing different amounts of aluminium isopropoxide catalyst from day 0 to day 31 of placement in clayloam soil.
  • Figure 15(a) shows change in Mn
  • Figure 15 (b) shows change in Mp.
  • Figure 16 is a graph showing the average molecular weight (Mw) of PC film of samples numbers 2, 3 and 4 referred to in Example 17 initially and after 10, 35 and 55 days of being buried in wet tropical soil.
  • Figure 17 is a graph showing the average molecular weight (Mn) of PCL film of samples numbers 2, 3 and 4 referred to in Example 17 initially and after 10, 35 and 55 days of being buried in wet tropical soil.
  • Figure 18 is a graph showing the polydispersity (PD) of PCL film of samples numbers 2, 3 and 4 referred to in Example 17 initially and after 10, 35 and 55 days of being buried in wet tropical soil.
  • Figure 19 is a graph showing the molecular weight (Mn and Mw) and
  • the pellets are formed by coextrusion of a thermoplastic tube, such as formed of a polycaprolactone-polylactic acid copolymer, with spaced portions of a core matrix, such as a paste comprising a urea composition, clay and ionic polyurethane.
  • a thermoplastic tube such as formed of a polycaprolactone-polylactic acid copolymer
  • a core matrix such as a paste comprising a urea composition, clay and ionic polyurethane.
  • the coextruder comprises a number of interlocking parts (1 1 -14) providing tube resin inlet (15) for feeding polymer tube resin under pressure to an annular extrusion port (16) and a matrix extrusion channel (17 ) in which discrete portions of matrix may be conveyed in a sleeve (18) of air.
  • the portions of matrix may be separated by a resin for forming the ends of the pellets as shown in Figure 13.
  • FIG. 1 (a) there is shown the intermediate structure (20) comprising a length of an outer tube (21 ) of the thermoplastic such as polycaprolactone-polylactic acid copolymer, with coextruded spaced portions of a core matrix (22).
  • the thermoplastic such as polycaprolactone-polylactic acid copolymer
  • the individual pellets (24) may be formed by cutting the tube between portions (22) of matrix and collapsing the tube (21 ) to form ends (23) of pellets (24) formed of the tube polymer. This operation may be performed in separate steps as shown in Figure 1 1 or the separation of the pellets (24) may be carried out in a process step in which the tube is collapsed between portions of matrix (22) and cut in a process continuous with the collapsing action, for example using opposed blades.
  • the length of coextruded structure (25) comprises a length of tube (21 ), spaced portions of matrix (22) and portions of resin (26) between portions of matrix ( Figure 13(a)).
  • the tube is cut through portions of the resin (26) to separate the pellets and provide pellet ends (27) formed of the resin ( Figure 13(b)).
  • Particle size was measured by Wyatt Dyna Pro Plate Reader Wyatt Technology Corporation, 6300 Hollister Ave, Santa Barbara, CA 931 17-3253.
  • the viscosity of polymer solution was measured by Brookfield digital rotary viscometer, model 94800-0.
  • Tetrahydrofuran THF was used as eluent and solvent in GPC measurements, using WATERS 2695 Separations module, WATERS 2414 Refractive Index, four PLGel columns (3x5 m MIXED-C AND 1 X3 M Mixed-E) in a series with flow 1 .0 imL/min. Molecular weight was determined according to calibration on polystyrene standards.
  • DSC was performed on a Mettler Toledo DSC821 using samples ( ⁇ 5 mg weight) at a heating rate of 10 /min under nitrogen purge . The samples were stored for 48 h under a vacuum at room temperature (RT) (0.1 Torr) prior to analysis. Tensile testing was performed on an Instron Model 4468 universal testing machine following the ASTM D 882 - 02 test method at ambient temperature (23 *C) with a humidity of around 54 %.
  • FTIR Fourier transform infrared
  • THCO 2 MTOT x CTOT x 44/12
  • MTOT is the total dry solids, in grams, in the test material at the start of the test
  • CTOT is the proportion of total organic carbon in the total dry solids in the test material, in grams per gram
  • 44 and 12 are the molecular mass of carbon dioxide and the atomic mass of carbon, respectively.
  • (CO 2 ) T is the cumulative amount of carbon dioxide evolved in each bioreactor containing test material, in grams per bioreactor. Solvent cast samples of films containing the polymer were prepared.
  • the laboratory method also included extruded with active urea core were placed in sealed pill bottles containing water. This assembly was then placed in a constant temperature oven until the water was sampled for urea in solution. Multiple pill bottles were uses so a range of time intervals could be investigated. Detection of urea in water solution was carried out by UV-VIS spectroscopy using a colourant
  • a calibration cure is first constructed to yield a ppm vs absorbance level at 420 nm. For those concentrations falling outside the calibration limits, dilutions of the original solution are made
  • PCL Polycaprolactone polymer
  • Example 1 Biodegradable polymer synthesis and composition: PCL-PLLA copolymer synthesis
  • PCL-PLLA polymer was synthesized by ring opening polymerisation using reactive extrusion.
  • the actual polymerization time (depending on the amount of catalyst added and the temperature conditions used) varies between two hours and up to two days. It has to be noted that the limitation in finalizing the polymerization is the time needed for the remaining monomer to diffuse through the already formed high viscous polymer in order to reach the reactive sites. The polymer obtained with such a process often has a low thermal stability in melt processing. The polymerization time was in this case two hours for samples as well for blanks.
  • Table 1 Mn, Mp and polydispersity (PDI) value for non-processes samples from bulk reactors after two hours of synthesis.
  • PCL and PLLA blends were prepared by extrusion process using granules of both PCL and PLLA polymers with different loading of the catalyst BuOSn in amounts of 0.5, 1 , 1 .5, 2 and 3% by weight of the polymer respectively.
  • PCLPLLA polymers were compounded at temperatures between 160-190 Q C by using a Haake twin screw extruder. The extruded blends were pelletized into pellets in order to feed to the extrusion of films process.
  • PCL/PLA blends were feed into the hopper of a film extrusion process with temperature profile 160-180 Q C. Three films were prepared of thickness 120, 160 and 200 microns.
  • Example 3 Hydrolytic degradation of PCL-PLLA co-polymer
  • Figure 1 shows the GPC Molecular weight distribution curves for the blank soaked in water after five weeks. Samples with increasing amount of ⁇ -caprolactone and lower level of catalyst have higher Mp than those synthesized with higher amount of catalyst.
  • Figure. 2 shows Influence of increasing humidity on degradation of samples and blends in controlled chamber.
  • Figure 3 shows the hydrolytic degradation of PLA-PCL films with varying amounts (%w/w) of Sn catalyst after a) 1 , and b) 2 months.
  • the number average molecular weight (g/mole) is determined against a polystyrene standard.
  • Example 5 Hydrolytic degradation of PCL- PLLA blend film containing different Catalysts
  • Figure 4 shows the hydrolytic degradation of PLA-PCL films with varying catalyst after 44 days a). Number average molecular weight Mn- and weight average molecular weight (Mw) (g/mole) b) Polydispersity (PD) against a polystyrene standard at time 0 (PD_T0) and at 44 days (PD_T0).
  • Example 6 Hydrolytic degradation of PCL- PLLA blend film containing different concetration of aluminium isopropoxide (AIPO)
  • PCL-PLLA copolymers containing five different concentration of Aluminium isopropoxide were prepared following the general procedure described in Example 1 .
  • the samples were compress moulded into thin films and hydrolytic degradation was evaluated in accordance with tests described in Example 4.
  • the polymer showed significant reduction in molecular weight in all samples containing different amount of catalyst after 31 days and results are summarised in Figure 5.
  • Figure 5 Hydrolytic degradation of PLA-PCL films with different concentration of catalyst Aluminium isopropoxide (ALISO in Figure 5 (a) and (b)) after 0 days in the left hand column of each pair and 31 days in the right hand column of each pair of columns.
  • Figure 5(a) compares molecular weight (Mn-) and
  • Figure 5(b) compares polydispersity (PD).
  • the testing assembly (1 ) includes two inclined tube sections (2,3) separated by a membrane (4) in a "V" configuration with urea solution (5) in a tube section (2) on one side of the membrane (4) and distilled water (6) in the tube section (3) on the other side of the membrane from the urea solution (5).
  • Figure 7 shows urea transport across membranes at 22 ⁇ C, 35 ⁇ and 50 ⁇ C.
  • Figure 7 demonstrates that PLLA-PCL films with a thickness of 120 ⁇ allow minimal transport of urea across the film at ambient (22 ⁇ C) temperature.
  • ther e was a systematic increase in the rate of urea transport across the films.
  • the temperature was increased to 50 ⁇ C, resulting in considerable increa se in urea transport across the film and more rapid breakdown or failure of the films.
  • Urea transport across membranes at 50 ⁇ C showing that addition of catalyst leads to the early onset of film degradation and decrease of 'zero release' period.
  • Figure 8 shows urea transport across 160 ⁇ thick films with the addition of 0.5 wt% monobutyltin oxide (BuOSn) catalyst (three left hand side plots) and without the addition of 0.5 wt% monobutyltin oxide (BuOSn) catalyst (three right hand side plots).
  • BuOSn monobutyltin oxide
  • Figure 9 shows the impact of increasing thickness of the film on urea transport rates.
  • the results for urea transport across membranes at 50 ⁇ C show that increased thickness of the coating leads to a slightly increased 'zero release' period and slower rate of transition to total failure of the coating.
  • Example 8 Polymer coated matrix: Co-extrusion of urea matrix with PCL polymer
  • Urea/bentonite clay matrix as prepared in Example 10 is flowable at ambient temperature.
  • PCL low molecular weight polycaprolactone
  • tubing was cooled either with air or by passing through a water bath and taken off with a conveyor belt.
  • the tubing wall thickness and overall diameter was varied by altering the polymer feed rate, melt temperature, nutrient matrix feed rate, air flow and haul off rate.
  • Example extruder conditions Extruder temp profile 20-90 die temp 1 10 ⁇ C, screw speed 120 rpm, polymer feed rate 45%, melt pump 20%, nutrient feed rate 2 imL/min.
  • Co-extrusion of urea with PCL polymer may be conducted in accordance with the scheme shown in Figures 1 1 (a) and 1 1 (b) to provide pellets shown in Figure 12.
  • Example 10 urea matrix: Urea-bentonite clay matrix composition Method 1
  • a biodegradable ionic polyurethane was prepared by two step solution polymerisation methods in water. Following precursors were used in the polymer.
  • PCL (MW 1000, 20.00 g), IPDI (8.20 g), BMPA (0.432g), TEAe (0.309 g), EDA (0.774 g Polyol and pre-dried BMPA (0.43g).
  • the mixture was accurately weighed into a three neck flask equipped with mechanical stirrer, dropping funnel and nitrogen inlet. The mixture was heated with stirring to 100°C for one hour until all BPM dissolved. The reaction temperature was lowered to 90°C and IPDI (8,20 g) was added to the above polyol mixture and reacted for another 4 h at the 90°C.
  • the polymer showed an average particle size distribution of 425 ⁇ 53 nm with a viscosity of 625 mPa.s.
  • Example 12 Urea Release from urea/bentonite clay matrix at room temperature
  • Urea prills (average weight 22 mg) were rolled and coated in molten PCL (MW. 10K) at 100-150 ⁇ C. The coated prill was then d ropped into cold water from approximately 1 .2 m height. Prills were retrieved from the water and patted dry with tissue paper. A single coated prill was then placed in 25.00 mL of water in a sealed pill bottle and left at room temperature until tested. Testing was carried out by calibrated UV-VIS interpolation by taking 2.00 mL of immersion water made up to 15 mL followed by a colourant of p-dimethylaminobenzaldehyde for free urea in water. The test showed the loss of 100% urea in 8 days. A coating with a mixture of different MWs of PCL in different ratios is also achieved using above method to control the release of urea from the coating.
  • Figure 14 shows the urea percentage loss from urea prill coated with PCL 10,000 dalton at room temperature.
  • Example 14 Urea release from extruded PCL polymer tube filled with urea matrix at different temperatures
  • Hot melt sealed tablets were prepared by method given in Example 6 using PCL polymer 6800 with no catalyst. The hot sealed tablets were tested prior to the test by squeezing to make sure the matrix did not move within the extruded tablet.
  • Four single pellet (average 0.13 g)) was placed in 25.00 mL water sealed in a pill bottle. This was placed in a constant temp oven at 50 ⁇ C. A 2 mL samp le of this water was then taken at regular time intervals for UV-VIS analysis for free urea in solution.
  • the table shows mg of free urea lost (from a possible 22 mg contained in the pellet). There are some inconsistencies in free urea detection, likely from the contamination during pellet preparation, however, after 69 days there was only a trace loss from all tablets
  • Example 15 Urea release from extruded PCL polymer containing BuOSn catalyst tube filled with urea matrix
  • Hot melt sealed tablets were prepared by method given in Example 6 using PCL polymer 6800 with 0.5 wt% catalyst. The hot sealed tablets were tested prior to the test by squeezing to make sure the matrix did not move within the extruded tablet.
  • Four single pellet (average 0.13 g)) was placed in 25.00 imL water sealed in a pill bottle. This was placed in a constant temp oven at 50 ⁇ C. A 2 imL sample of this water was then taken at regular time intervals for UV-VIS analysis for free urea in solution. The table shows mg of free urea lost (from a possible 135 mg contained in the pellet).
  • Example 16 Degradation of PCL- PLLA films with and without catalyst films in soil
  • Figure 15 shows GPC results of polymer samples from soil test after 0 days (left hand column in each group) and 31 days (right hand column in each group) where Figure 15 a) shows the number average molecular weights (Mn-) and in Figure 15 (b) the polydispersity (PD) is shown).
  • Example 17 PCL degradation and Urea release from PCL coated urea in field conditions
  • Samples of the coated fertiliser and biodegradable film listed in Table 7 were subjected to field trials in sugarcane fields in three different locations within the wet tropics. In the trials, plastic mesh bags each having a number of separate pouches were used to retain the samples of coated urea pellets and polymer film strips and were buried to examine degradation of the samples in tropical conditions.
  • PCL strips were of dimensions 6 cm X 1 cm and thickness of approximately 0.5 mm
  • FIG. 16 is a graph showing the average molecular weight (Mw) of PC film of samples numbers 2, 3 and 4 referred to in Example 17 initially and after 10, 35 and 55 days of being buried in wet tropical soil.
  • Figure 17 is a graph showing the average molecular weight (Mn) of PCL film of samples numbers 2, 3 and 4 referred to in Example 17 initially and after 10, 35 and 55 days of being buried in wet tropical soil.
  • Figure 18 is a graph showing the polydispersity (PD) of PCL film of samples numbers 2, 3 and 4 referred to in Example 17 initially and after 10, 35 and 55 days of being buried in wet tropical soil.
  • Figure 19 is a graph showing the molecular weight (Mn and Mw) and polydispersity (PD) of granules of Sample number 1 of Example 17 initially and after 10, 35 and 55 days of being buried in wet tropical soil.

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Abstract

La présente invention concerne un procédé de préparation de granulés destinés à la libération retardée d'un principe actif, lequel procédé consiste : à extruder un tube de polymère biodégradable ; à insérer à l'intérieur du tube une pluralité de parties espacées longitudinalement d'une matrice centrale comprenant le principe actif; et à sceller le tube entre les parties espacées longitudinalement afin de former des granulés discrets comprenant des parties de matrice centrale.
PCT/AU2017/051067 2016-09-29 2017-09-28 Procédé de production de granulés pour l'administration contrôlée d'un principe actif Ceased WO2018058195A1 (fr)

Applications Claiming Priority (2)

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CN111285720A (zh) * 2020-02-25 2020-06-16 中北大学 反应挤出制备脲甲醛/聚丁二酸丁二醇酯生物降解聚合物缓控释材料
CN111285721A (zh) * 2020-02-25 2020-06-16 中北大学 反应挤出制备的含氮磷钾三元生物降解聚合物缓控释纳米材料

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CN110218083A (zh) * 2019-05-30 2019-09-10 龚建林 一种陶瓷填料的制备方法
CN111285720A (zh) * 2020-02-25 2020-06-16 中北大学 反应挤出制备脲甲醛/聚丁二酸丁二醇酯生物降解聚合物缓控释材料
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CN111285720B (zh) * 2020-02-25 2021-11-09 中北大学 反应挤出制备脲甲醛/聚丁二酸丁二醇酯生物降解聚合物缓控释材料

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