A superabsorbent-based composition for hydrostimulatory coating of seeds and a method of coating seeds with the composition

Abstract

A superabsorbent-based composition for hydrostimulatory coating of seeds comprises: a superabsorbent polymer having a water absorption capacity of at least 50 times its weight, in the range of 20 to 35 wt. % of the composition; a non-aqueous, non-flammable solvent in the range of 40 to 80 wt. % of the composition; and a stabiliser for preventing premature swelling of the superabsorbent polymer in the solvent, in the range of up to 15 wt. % of the composition. A method of coating a seed with said composition is also disclosed.

Description

[0001] A superabsorbent-based composition for hydrostimulatory coating of seeds and a method of coating seeds with the composition

[0002] Field of Invention

[0003] A superabsorbent-based composition, in particular for hydrostimulatory coating of seeds and a method of coating the seed with the composition. The main use is in agriculture and horticulture. A superabsorbent (SAP = super absorbent polymer) is used to coat the seeds treated with the active ingredients to bind water in the soil to increase the germination in the absence of water and consequently to increase the yields of crops, or to reduce the frequency of irrigation and reduce water evaporation from the soil, respectively. The composition contributes to preventing the redundant leaching of active ingredients into environment and improves the uptake of active ingredients. The ingredients used in combination with SAP will improve flow properties (reduce friction and abrasion) between the seeds and reduce a dustiness and any wear on the seed drill machine parts. The composition can be used as a carrier of active ingredients, fertilizers and as a depth stabilizer.

[0004] Background of the Invention

[0005] Agricultural production depends inter alia on the quality of seeds. The better the seed (with high germination capacity, pest resistance, ability to effectively use individual soil components such as nutrients and water), the greater the likelihood of higher yields. During germination, several metabolic processes take place in the seed. The germination time depends on the seed quality, environmental factors (temperature, water presence) and the like. However, the aim is to achieve optimum germination and defined plant growth even under adverse climatic conditions.

[0006] Larger root biomass makes the crop more resilient. A more vigorous plant produces a robust yield even in water scarcity.

[0007] In recent years, the question of lack of soil moisture at the time of germination has come to the fore. In the past, the problem of seed germination in the absence of moisture was solved by a variety of hydration techniques designed to ensure rapid and optimal germination in order to help achieve stable production under appropriate economic conditions. For this reason, the seed was treated by various techniques before planting.

[0008] It is possible to find methods in the prior art whereby superabsorbent (SAP) is applied to the seeds in powder form. With various variations, these are methods where an adhesive is applied to the seed and then the (powdered) SAP is added (powdered) (CN 106471952 A), or the ability of SAP to adhere to a wet surface is utilized (US 2012277099 Al), wherein the SAP can absorb water into its structure very quickly and efficiently, thereby attaching itself to the seed surface if the seed surface was previously wet. In both cases, SAP is dosed in powder form. In both cases, it is necessary that the seed be coated with either an adhesive or a substance that comprises a certain amount of water and leaves the seed surface suitably moist before dispensing SAP. Thus, in both cases, pre-treatment is required, which is one extra operation before dispensing SAP powder.

[0009] Both of these cases present several disadvantages. Most of these disadvantages result from the powder form of SAP. By dosing SAP powder, it is not possible to achieve a homogeneous seed coverage. Inhomogeneity of coverage is within one seed, but also in case of comparison of seeds with each other, or even between batches. A further disadvantage is that, in the case of powdered SAP, the SAP particles do not adhere to the seed surface sufficiently intensively and fall off during storage and sowing activities. This deficiency increases SAP consumption, and it reduces the effectiveness of the dressing process. SAP particles also increase the uptake of SAP, which do not come into contact with the seed surface during the dressing process because they are sucked off by the suction device.

[0010] The SAP particles adhered to the surface by the above methods result in a deterioration of the flow properties of the seed, and seed blockage may occur in the seed drill devices, or in other operations where the seed is transported by sifting. At the same time, the SAP particles anchored in this way are very sensitive to atmospheric moisture, which causes the SAP to stick, and thus to bond the seeds to each other, which causes storage, transport and sowing problems.

[0011] A significant disadvantage is that in the above methods the SAP dosing alone has to be preceded by a seed pre-treatment operation in order to attach the SAP particles to the surface. Such a limitation brings a further reduction in efficiency with respect to the time required for pre-treatment.

[0012] The pre-treatment process also affects the different quality of SAP attachment on the surface as well as the amount of SAP attached, which can have a negative effect if too much SAP or SAP adheres to the seed, or no impact if too little SAP is attached to the seed. Different amounts of SAP attached can result in different emergence dynamics and later developed plants, which can reduce overall yield.

[0013] From the point of view of health protection, the mentioned methods bring complications as very small SAP particles get into the atmosphere, thus worsening working conditions. The SAP particles may be released into the atmosphere when the SAP is metered into the seed dressing device, the discharge of the treated seed as well as the subsequent treatment of the treated seed. The technological disadvantage is the limited use of seed dressing devices. As a priority, seed dressing devices are equipped with automatic liquid dispensing devices, but this possibility for SAP powder dispensing cannot be used. For dosing powder materials, the seed dressing device needs to be supplemented with a dosing device for powder materials, which brings additional costs. Application of SAP powder in seed dressing devices is not possible where powder dosing equipment is not available. In the mentioned method(s) it is further required that the application of SAP be followed by the dosage of singulating substances (Ss), also in powder form, requiring an additional powder material dosing device and hence additional costs.

[0014] The use of methods in continuous seed dressing devices would also be very problematic, or even impossible.

[0015] The international patent application WO 2005059023 Al discloses a superabsorbent-based suspension suitable for coating a seed, comprising a superabsorbent, an adhesive dispersed or dissolved, preferably in an aqueous solution, and a bioactive growth-stimulating additive. The superabsorbent is a grafted starch copolymer (copolymer backbone) with e.g. acrylonitrile, acrylic acid or acrylamide (grafts). The suspension is applied to the seeds in an aqueous solution, causing premature absorption of water by the superabsorbent during the deposition process, bonding and aggregation of the individual treated seeds, and clogging of the seed drill devices.

[0016] The international patent application WO 0166668 A2 discloses a composition suitable for seed coating, comprising a sodium polyacrylate superabsorbent in the amount of 0.3 wt. %, a fertilizer (active ingredient) in the amount of 1.2 wt. %, polyethylene glycol 1450 in the amount of 23.5 wt. % and ethanol in the amount of 75 wt. %. This composition was applied to the surface of Pickseed™ grass seed. Another disclosed composition suitable for seed coating includes a sodium polyacrylate superabsorbent in the amount of 4.4 wt. %, a fertilizer (active ingredient) in the amount of 15.6 wt. %, polyethylene glycol 1450 in the amount of 30 wt. % and ethanol in the amount of 50 wt. %. This composition was applied to the surface of a rice seed at a ratio of 3.3: 1 (seed: composition). Polyethylene glycol is used in the composition in particular as a lubricant and a component, which will provide better mutual compatibility of other polymers, but not as an adhesive or film forming agent. A disadvantage is also the use of sodium salt of polyacrylate, which salinizes the soil by the addition of sodium cations.

[0017] The publication of Chen, Junwu et al. (Swelling behaviours of polyacrylate superabsorbent in the mixtures of water and hydrophilic solvents) describes the behaviour of polyacrylate superabsorbents (sodium polyacrylate) in a mixture of water and hydrophilic solvents (e.g., 20 %, 40 % and 60 % methanol or ethanol). The equilibrium of water absorption by the superabsorbent was determined at 10 min. and 48 hours, whereby the authors concluded that the addition of a low-polarity solvent (methanol, ethanol) greatly reduces the absorption capacity of the superabsorbent, especially on a short time scale. The publication details only sodium polyacrylate, but not its copolymers or polyacrylates with other counterions.

[0018] The publication of You, Ying-Cai et al. (Synthesis and swelling behaviour of crosslinked copolymers of neutralized maleic anhydride with other monomers) describes the behaviour of a maleic anhydride / acrylamide copolymer and a maleic anhydride / acrylamide / hydroxyethyl methacrylate copolymer with N,N‘ -methylene bisacrylamide as a crosslinking agent. The publication discusses the absorption capacity of these copolymers in solutions of alcohols (methanol, ethanol, glycol, glycerol) and water, also based on the synergy of non-ionic (OH, CONH2) and ionic functional groups (COOK). Excess ionic functional groups increase the hydrophilicity and absorption capacity of the copolymer, while excess non-ionic groups reduce the absorption capacity. An apparent trend is a decrease in the absorption capacity of said copolymers with increasing concentrations of alcohol in aqueous solution (20 %, 40 % and 60 %), with ethanol showing the greatest decrease in absorption capacity of all the alcohols tested. Due to two carboxyl groups within one monomer unit, a disadvantage of maleic anhydride is a higher sensitivity to multivalent ions (2+, 3+) present in the soil (mainly Ca2+, Mg2+, Al3+), stronger intramolecular interactions within one polymer chain, more intensive flocculation between different polymer chains, and too strong (even irreversible) anchorage of monovalent ions (Na+, K+).

[0019] The international patent application WO 2013158284 Al describes a method of reducing dustiness in seed sowing by means of a lubricant component applied to a seed with a layer of active substances (pesticides, etc.). The lubricant component comprises waxes of synthetic, vegetable and / or animal origin (e.g. polypropylene wax), and is characterized by lower seed dustiness than with talc or graphite. The lubricant component does not include any superabsorbent that would increase the absorption capacity or even ensure the absorption of water in this layer.

[0020] The international patent application WO 2007103076 Al discloses a seed coating composition for improved binding of a bioactive component (e.g. insecticide, fungicide), while also improving the flow properties of the coated seeds in transport and sowing. The composition includes an adhesive (e.g., polyvinyl acetate or polyacrylate), a wax (e.g., natural, mineral or synthetic wax), a pigment (e.g., mica coated with titanium dioxide) and a stabilizer (suspending agent, humectant, biocide). The composition is applied wet to the seed in an aqueous solution, which in the case of polyacrylate (although functioning here as adhesive) may cause premature absorption of water before sowing into the soil. The US patent application US 2015267063 Al discloses a seed coating composition comprising an antistatic or electrically conductive additive, e.g. an allotropic modification of carbon (e.g. graphite) or an electrically conductive polymer.

[0021] The publication of Black et al. discloses the use of graphite and talc to improve seed flow properties.

[0022] The review of Wissler (Journal of Power Sources 156 (2006) 142-150) discloses various functional and structural properties of generic graphites and specific types thereof, such as flake graphite.

[0023] The Slovak utility model application SK 50110-2016 U1 and the Slovak patent application SK 50069- 2016 A3 disclose a combination of substances (a coating composition) comprising a superabsorbent (polyacrylamide, polyacrylate or starch copolymers) and an adhesive solution in a mixture of water and ethanol, and preferably lubricants and biologically active substances. Superabsorbent present and applied to the seed separately in a dry state, which may increase dustiness, abrasion of the seed surface and uneven surface of the superabsorbent layer. The water-ethanol mixture is adapted to dissolve the adhesive (30 to 50 % by weight of the adhesive solution), wherein said amount of ethanol (20 to 40 % by weight of the adhesive solution) and water (10 to 50 % by weight of the adhesive solution) could cause premature absorption of water by the superabsorbent during deposition. Moreover, a method of seed coating with this combination in two steps is described, first the adhesive solution is applied to the seed and only in a subsequent step, the superabsorbent in a dry state.

[0024] The US patent application US 2016219871 Al discloses seed treatments by means of polymeric hydrogels capable of absorbing water for improving seed germination performance in low moisture environments. Seed treatment compositions based on a cross-linked potassium poly-acrylate (BountiGel™ hydrogel by mOasis Inc.) are disclosed and exemplified on turf, com and broccoli seeds. This hydrogel is coated on the seeds in a rotary seed coating machine (e.g. Aginnovation Rotary-6 seed machine) in a sequential manner in a powder formulation 1 following a pre-coating step of adhesive solution A. After coating the seed with the powder formulation 1, the seed is additionally coated with an adhesive solution B and a powder formulation 2, i.e. in the sequence A -> 1 -> A -> 1 -> B -> 2. Overall, the whole composition is coated on the seed in the amount of 7.5 wt. %. The adhesive solution A comprises 10-20 vol. % polyvinylpyrrolidone PVP40 in dichloromethane. The powder formulation 1 comprises 5 g cross-linked potassium poly-acrylate and 5 g powdered talc. The adhesive solution B comprises 20 vol. % polyvinyl acetate in dichloromethane. The powder formulation 2 comprises 1 g powdered potato starch and 9 g powdered talc. Furthermore, a method of coating a seed in a rotary seed coating machine is disclosed and exemplified on turf, com and broccoli seeds. Moreover, the seed coating composition can comprise an active ingredient for improving the seed properties, e.g. a nutrient (N, NCU, K, P, Mg, Ca), a fertilizer, a pH regulating agent, a herbicide, a pesticide, or a fungicide. The international patent application WO 8501736 Al discloses a water absorbent seed coating composition comprising finely divided polyacrylate (no counterion indicated), finely divided polyacrylamide and finely divided graphite as a sticker. The polyacrylate and polyacrylamide form an “intimate mixture”, but not a copolymer. Nonetheless, the polyacrylate can form a copolymer with grafted starch chains. The particles of polyacrylate and polyacrylamide preferably do not exceed 1000 pm, e.g. 60 pm for polyacrylate and 300 and 20 pm for polyacrylamide, the graphite particles preferably do not exceed 200 pm, e.g. 10 to 20 pm. The composition further comprises an active ingredient, i.e. a fertilizer, an insecticide, a pesticide, a fungicide or nitrogen fixing bacteria. In a preferred embodiment, the composition comprises 33.3 % graphite (10 to 20 pm particle size), 33.3 % internally cross-linked polyacrylate copolymer with grafted starch chains (60 pm particle size), 16.0 % cross-linked polyacrylamide (300 pm particle size) and 17.4 % cross-linked polyacrylamide (20 pm particle size). The coating step is performed either directly on the seed in a dry process (not indicating the number of steps) or in the soil prior to sowing in the form of aqueous slurry.

[0025] The article “Super absorbent polymer seed coatings promote seed germination and seedling growth of Caragana korshinskii in drought, Su Li-Qiang et al., 2017” describes a study of individual superabsorbents in seed coating compositions (e.g. Caragana korshinskii seeds) in five groups A-E, namely polyacrylamide (A), sodium polyacrylate (B), denatured polyvinyl alcohol branded as Balite™ efficient poly agent (C), copolymer of potassium polyacrylate and polyacrylamide branded as Hankeshu™ aquasorb (D) and a copolymer of sodium polyacrylate and polyacrylamide branded as Zhengyuan™ aquasorb (E). Ethylene cellulose was used as an adhesive (1.5 % in absolute ethanol) and it was coated in solution prior to coating the seed with the superabsorbent. A mixture of attapulgite clay (= hydrated magnesium aluminium silicate) and talc was used as a filler and a lubricant additive in 2: 1 ratio. The content of copolymer of potassium polyacrylate and polyacrylamide in the tested compositions was 1 wt. %, 4 wt. %, 7 wt. %, 10 wt. % and 13 wt. % and proved to be the most efficient superabsorbent due to the highest water sorption capacity, while the remaining components of the mixture were always attapulgite clay and talc in 2: 1 ratio. The seed coating step was performed sequentially in a coating machine, whereby the adhesive was coated first in ethanolic solution, followed by the coating of powdered remaining components, which was repeated for 15 cycles.

[0026] The US patent US 7504445 B2 discloses an aqueous seed coating superabsorbent composition comprising a copolymer of potassium or ammonium polyacrylate and polyacrylamide (PAM, e.g. branded as Flobond™), preferably with 10-40 mol. % of polyacrylate in the copolymer, and an NPK fertilizer and cellulose mulch. The resulting dose of superabsorbent represents 0.01-0.1 wt. % of the seed. The document discusses the substitution of sodium with potassium or ammonium due to soil salinization. Prior to seed coating, an aqueous solution of the copolymer of potassium or ammonium polyacrylate and polyacrylamide is prepared, to which solution an NPK fertilizer, cellulose mulch and the seed itself is added (in this order). The suspension is mixed for 30 min and is then sprayed on the soil.

[0027] In the publication of Dan Anderson, 2014 (retrievable from https: / / www.agweb.com / article / talc_and_graphite_what_you_need_to_know_before_you_plant_NAA _Dan_Anderson, 27 November 2020) a composition comprising talc (as a lubricant) and graphite (as an antistatic additive) in the ratio 80:20 is disclosed, in order to improve flow properties of seeds and eliminating electric charge in seed planting devices. Further active substances are possible in the mixture.

[0028] The US patent application US 2019000075 Al discloses a superabsorbent-based suspension suitable for hydrostimulatory coating of seeds, comprising a superabsorbent in the form of a copolymer of sodium acrylate and acrylamide in the range of 5 to 60, preferably 15 to 35 wt. %, binding and fdm -forming agents (such as PVP, PVAc, graphite) dispersed or dissolved in an aqueous solution, lubricant additives (such as graphite at a concentration of 67 wt. %) and suitable for improving flow properties of seeds and further additives, such as mineral or organic salts (potassium salts), dispersant organic polymers or biologically active substances for improving properties of the seed.

[0029] The international patent application WO 9103149 Al discloses a superabsorbent-based semi-solid matrix composition suitable for hydrostimulatory encapsulation of seeds, comprising a superabsorbent in the form of a copolymer of potassium acrylate and acrylamide in the range of 1 to 25 wt. % of the dry matrix, binders (such as PVA or PVP) in the range of 0 to 40 wt. % of the dry matrix and further additives, such as peat moss, non-ionic surfactant and biologically active substances for improving properties of the seed.

[0030] The UK patent application GB 1591415 A discloses a dry particulate soil matrix composition of soil and soil amendments for improving water retention around the seed, comprising soil, a superabsorbent in the form of a copolymer of potassium acrylate and acrylamide, lubricant additives (such as graphite) suitable for improving flow properties of seeds in the range of 1 to 2 wt. % and further additives, such as soil amendments, possibly affecting plant growth, such as water, organic alcohols or talc without any apparent specific purpose.

[0031] The international patent application WO 202307449 Al discloses a liquid suspension comprising up to 30 wt. % superabsorbent polymer, such as starch-g-poly(2-acrylamide-co-2-acrylate) potassium salt; a solvent system based on water and a glycolic solvent, such as monoethylene glycol, diethylene glycol, propylene glycol, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether; and a surfactant with no amount specified, such as a block copolymer ethylene oxide-propylene oxide-ethylene oxide or a block copolymer ethylene oxide -propylene oxide. The waterglycol ratio is 1:5 to 5: 1 and the content of the total solvent is at least 10 wt. %. No stabiliser, adhesives, lubricants or rheology-modifiers are specified. Surprisingly, this composition causes an uncontrollable and premature swelling of the superabsorbent polymer in higher amounts in the presence of water and a hygroscopic, glycolic solvent, thus limiting its application and expiry date. The amount of the SAP(s) used in the examples of said document is up to 10 wt. %, which may solve the problem of premature swelling, but would require large volumes of the composition to coat the seeds, thus increasing costs and coating time. Additionally, the particles of the superabsorbent polymer may result in uneven distribution on the seed surface and fall off over time, which increases dustiness. Furthermore, no seed coating procedure is disclosed.

[0032] The European patent EP 4007796 Bl discloses a suspension for hydrostimulatory coating of seeds, comprising a superabsorbent in the form of a copolymer of acrylate and acrylamide, preferably potassium salt, in the range of 25 to 40 wt. % of the suspension; adhesives (such as polyvinyl acetate) dispersed or dissolved in a solution of water and ethanol and / or of water and isopropanol, wherein the dispersion or solution of the adhesives comprising water in the range of 0.1 to 8 wt. % of the suspension, ethanol and / or isopropanol in the range of 40 to 70 wt. % of the suspension and adhesives in the range of 1 to 10 wt. % of the suspension; further lubricant additives (such as talc) for improving flow properties of seeds in the range of 0.1 to 15 wt. % of the suspension; and an antistatic additive (such as flake graphite) for eliminating electric charge in the range of 0.1 to 5 wt. % of the suspension. The lubricant additive has the function of improving flow properties of the seed, counteracting the mutual bonding of the seeds and the formation of clumps, especially after evaporation of the volatile components of the suspension, and preventing formation of agglomerates from individual seeds and unacceptable flow properties. The presence of alcohol solvent causes this suspension to be flammable, therefore difficult to handle and distribute.

[0033] The Chinese patent CN 111718554 B discloses a noise-dampening composition comprising a superabsorbent polymer, such as a copolymer of starch, polyacrylate and bentonite; water absorbed in the SAP; and ethylene glycol in a weight ratio to SAP of app. 1: 1. This composition is not used for seed coating.

[0034] The US patent application US 2023200380 Al discloses a polyether, in particular a statistical copolymer of propyleneoxy and ethyleneoxy units (see examples 10, 11, 12, 16, 17 of said document) as well as polypropylene glycol (see examples 13, 14, 15 of said document) or their mixtures (see examples 15+12, 15+10, 15+14 of said document) for seed treatment and as active ingredient carrier. No SAP or other additives are specified. The international patent application WO 2020254936 Al discloses a non-flammable composition comprising a super-absorbent polymer, such as starch-g-poly(2-acrylamide-co-2-acrylate) potassium salt; water absorbed in the SAP; viscosity control agent, such as talc, zeolite or amorphous silica in the form of precipitated silica or fumed silica to provide a uniform dispersion of SAP in water (see example 15 of said document); and an antimicrobial agent, such as bronopol (being a modified glycol, not used as a solvent due to insufficient amount). The non-flammability of the composition is based on the water content absorbed in the SAP. This composition is not used for seed coating.

[0035] The Chinese patent application CN 106366822 A discloses an anti-freeze coating composition comprising a super-absorbent polymer, such as a copolymer of starch, acrylate and acrylamide; water; and a solvent, such as isopropanol, ethylene glycol ether, propylene glycol ether, polyethylene glycol. This composition is not used for seed coating.

[0036] The international patent application WO 200425076 Al discloses a thermally insulating composition comprising a superabsorbent polymer SAP, such as starch-g-poly(2-acrylamide-co-2-acrylate) potassium salt; water; a viscosity inducing polymer, such as polyvinyl alcohol; a polyol, such as ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol or a copolymer thereof. In particular, the polyglycols ensure stable rheological properties at elevated temperatures. This composition is not used for seed coating.

[0037] The European patent EP 0851908 Bl discloses a lubricant composition comprising a super-absorbent polymer, such as starch-g-poly(2-acrylamide-co-2-acrylate) potassium salt; polyglycol, such as a copolymer of propyleneoxy and ethyleneoxy units; talc; and optionally an adhesive, such as vinyl resin based; and optionally water. This composition is not used for seed coating. The SAP content is either too low to provide for sufficient water absorption capacity in seed coating applications (example 3 of said document), or too high to prevent swelling of the SAP (example 2 of said document).

[0038] Summary of the Invention

[0039] It is an object of the invention to provide an environmentally neutral, non-flammable and stable composition for hydrostimulatory coating of seeds, which ensures controllable swelling of the superabsorbent polymer, water retention in the immediate vicinity of the sowed seed, higher germination and emergence of the plants, especially in dry conditions, and even growth. Further, the composition should be manageable and applicable to the seed in a more efficient manner than in the prior art with respect to meeting strict agricultural, industrial and safety standards, especially flammability, and with improved mechanical properties of the coated seed (degree of swelling of the SAP, flow properties, dustiness, adhesion). The above-mentioned drawbacks in the prior art are remedied by the present superabsorbent-based composition suitable for hydrostimulatory coating of seeds, comprising a superabsorbent polymer having a water absorption capacity of at least 50 times its weight, a non-aqueous, non-flammable solvent, and a stabiliser for preventing premature swelling of the superabsorbent polymer in the solvent.

[0040] The superabsorbent is comprised in the range of 20 to 35 wt. % of the composition. The solvent is comprised in the range of 40 to 80 wt. % of the composition. The stabiliser is comprised in the range of up to 15 wt. % of the composition.

[0041] Preferably, the superabsorbent is in the form of a grafted polymer comprising: a starch, cellulose, lignin, chitosan, chitin, carrageenan, collagen, gelatine, alginate, polyacrylate, polyitaconate, polyglutamate, polyglycoside or xanthan backbone chain; and a polymer graft chain grafted on said backbone chain, wherein the polymer graft chain comprises any one of acrylate, acrylamide, acrylonitrile, or a copolymer thereof chosen from a copolymer of acrylate and acrylamide, a copolymer of acrylate and acrylonitrile, a copolymer of acrylamide and acrylonitrile, or a copolymer of acrylate, acrylamide and acrylonitrile. In addition to that, the superabsorbent can be selected from, but not limited to, a copolymer of acrylamide and sodium acrylate, a copolymer of acrylamide and potassium acrylate; a hydrolyzed starch-polyacrylonitrile; 2-propenenitrile homopolymer; poly(2-propenamide-co-2 -propanoic acid, sodium salt); starch-g-poly(2propenamide-co-2-propanoic acid, mixed sodium and aluminium salts); starch-g-poly(2-propenamide-co-2-propanoic acid, potassium salt); poly(2-propenamide-co-2- propanoic acid, sodium salt); starch-g-poly(propenoic acid), sodium salt; starch-g-poly(propenoic acid), potassium salt; poly-2 -propanoic acid, sodium salt; starch-g-poly(acrylonitrile) or poly(2-propenamide- co-sodium acrylate); starch / acrylonitrile copolymer; crosslinked copolymers of acrylamide and sodium acrylate; crosslinked polymers of acrylamide and sodium polyacrylate; anionic polyacrylamide; starch grafted sodium polyacrylates; crosslinked copolymers of potassium polyacrylate and polyacrylamide; sodium polyacrylate; superabsorbent polymer laminates and composites; partial sodium salt of crosslinked polypropenoic acid; potassium polyacrylate, lightly crosslinked; sodium polyacrylate, lightly crosslinked; poly(sodium acrylate) homopolymer; polyacrylamide polymers; carrageenan; agar; alginic acid; guar gums and its derivatives; and gellan gum.

[0042] Preferably, the superabsorbent is a grafted starch polymer comprising a starch backbone chain; and a copolymer of acrylate and acrylamide grafted on said starch backbone chain, preferably potassium acrylate or uncharged acrylic acid, wherein the potassium acrylate may be the result of partial or total neutralization of monomeric acrylic acid. The individual graft monomers may form an alternating, statistical, block or grafted copolymer structure, and may be in the proportion to each other, e.g. in the range of 25:75 to 75:25 (e. g. acrylate :acrylamide), e.g. 25:75, 30:70, 40:60, 50:50, 60:40, 70:30 or 75:25. During the seed germination, the superabsorbent gradually degrades, and the acrylamide chains are degraded to ammonia, which together with the acrylic potassium salt provides the seed with important biogenic elements and nutrients. If sodium salt is used, undesirable soil salination occurs, which is one of the disadvantages of the prior art. Starch backbone of the copolymer (or polyglycoside or xanthan backbone, or another biobased backbone) converts to carbohydrates accumulated as metabolically inert storage products back into forms that are usable for various biosynthetic and catabolic routes.

[0043] Preferably, the composition further comprises an adhesive for dispersion or dissolution in the solvent, in the range of up to 5 wt. % of the composition. The adhesive serves to fix SAP and other additives and can be added in the composition at a later stage, e. g. before the coating itself. The adhesive component also serves as a film-forming component. As adhesives, polyvinyl acetate (PVAc), polyvinyl acetate with different degree of hydrolysis (such as between 30 and 70 %, or between 33 and 66 %, wherein the upper limit of these ranges ensures sufficient solubility of the adhesive in the solvent), polyvinyl acetate or partially hydrolysed polyvinyl acetate copolymerized with ethyleneoxy units or quaternary ammonium salts, polyvinyl alcohol (PVA), hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, polyvinylpyrrolidone, lignin sulphonate, acacia gum, modified starch or carbohydrate can be used.

[0044] Preferably, the adhesive is polyvinyl alcohol because of its sufficient solubility in non-aqueous solvents, and as a compact and flexible polymer, it is capable of forming a thin and continuous film that closes the seed surface, thereby not exposing the superabsorbent to air humidity. In addition, polyvinyl alcohol has a desirable level of biodegradability on seed. Too rapid biodegradation of the adhesive layer could occur before seed sowing, while too slow biodegradation would not allow optimal plant growth.

[0045] Preferably, the non-aqueous, non-flammable solvent is chosen from a polyether comprising oxypropylene and / or oxyethylene units; glycol; glycol ether; aromatic alcohol or a mixture thereof, the solvent (or the mixture of solvents) being in the range of 40 to 80 wt. % of the composition (such as 50 to 70, 60 to 70 or 65 to 70 wt. %). Preferably, the adhesives are dispersed or dissolved in the solvent(s).

[0046] The term “non-aqueous solvent” means a substantially anhydrous solvent or a solvent comprising up to 1 wt. % of water. The term “non-flammable solvent” is a liquid substance having a flashpoint equal to or greater than 93 °C (Class IIIB of the classification by the Occupational Safety and Health Administration, see link https: / / www.ishn.com / articles / 96502-osha-fire-code-liquid-classifications-take-different-directions). Preferably, the polyether comprises propyleneoxy units, optionally copolymerized with ethyleneoxy units with an ethyleneoxy: propyleneoxy ratio of 80:20 to 0: 100; and has a molecular weight between 80 and 2000 g / mol, preferably between 400 and 2000 g / mol. Preferably, the polyether comprises ethyleneoxy units and has a molecular weight between 80 and 2000 g / mol, preferably between 400 and 2000 g / mol, such as PEG 100 or PEG 200. Preferably, the composition comprises polyether in the range of up to 10 wt. % of the composition. A higher amount than 10 wt. % causes the seeds to appear “oily” when coated, which is undesirable and complicates the coating process.

[0047] Preferably, the glycol is ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol or a mixture thereof. Preferably, the glycol ether is ethylene glycol monoalkyl ether or propylene glycol monoalkyl ether, such as ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol monopropyl ether, propylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monobutyl ether, diethylene glycol monobutyl ether, propylene carbonate or a mixture thereof. Preferably, the aromatic alcohol is benzyl alcohol, methylbenzyl alcohol, dimethylbenzyl alcohol or a mixture thereof.

[0048] The stabiliser serves to prevent uncontrollable and premature swelling of the SAP in the solvent, thus ensuring uniform dispersion of the SAP particles. A composition with a prematurely swollen SAP (e. g. within 4, 5, 6, 7 or 8 days, or within approximately a week of mixing the SAP with the solvent due to delivery to costumers) cannot be applied for seed coating due to its gel-like properties. A long-term stability of the composition is desirable, so that it can be sold without risk of expiration. The stabiliser may be graphite, talc, zeolite, clays (e. g. mica), fumed silica, amorphous silica, sodium sulphate, salts of fatty acids (e. g. calcium or magnesium stearate), molybdenum disulphide, polytetrafluoroethylene, polypropylene or mixtures thereof. Preferably the stabiliser is graphite, talc, fumed silica and / or amorphous silica or a mixture thereof. Preferably, the stabiliser is a mixture of fumed silica and amorphous silica in the ratio of 1:20 to 20: 1, such as 1:20, 1: 10, 1:5, 1:4, 1:3, 1:2, 1: 1, 2: 1, 3: 1, 4: 1, 5: 1, 10: 1 or 20: 1. Preferably, the stabiliser is a mixture of fumed silica and amorphous silica in the ratio of 1: 15 to 1:8, e. g. 1: 10.

[0049] Preferably, the stabiliser is also a lubricant additive - an auxiliary improving flow properties. The lubricant may be graphite, talc, zeolite, clays (e. g. mica), fumed silica, amorphous silica, sodium sulphate, salts of fatty acids (e. g. calcium or magnesium stearate), molybdenum disulphide, polytetrafluoroethylene, polypropylene or mixtures thereof. Preferably the lubricant is graphite, talc, fumed silica and / or amorphous silica or a mixture thereof. The composition comprises lubricant additives in the range of up to 15 wt. % of the composition. Preferably, the stabiliser is also a rheology-modifying additive, comprised in the composition in the range of up to 12 wt. % of the composition to improve flow properties of the composition. Preferably, the rheology-modifying additive is talc, fumed silica, amorphous silica, sodium sulphate, or a mixture thereof.

[0050] Preferably, the present composition comprises:

[0051] • the superabsorbent being a grafted starch polymer comprising a starch backbone chain; and a copolymer of potassium acrylate and acrylamide grafted on said starch backbone chain, in the range of 20 to 30 wt. % of the composition;

[0052] • the adhesive being polyvinyl alcohol in the range of up to 3 wt. % of the composition;

[0053] • the solvent being propylene glycol in the range of 65 to 70 wt. % of the composition; and

[0054] • the stabiliser being a mixture of: fumed silica in the range of up to 1 wt. % of the composition; and amorphous silica in the range of 4 to 6 wt. % of the composition.

[0055] Preferably, the present composition comprises:

[0056] • the superabsorbent being a grafted starch polymer comprising a starch backbone chain; and a copolymer of potassium acrylate and acrylamide grafted on said starch backbone chain, in the range of 20 to 30 wt. % of the composition;

[0057] • the adhesive being polyvinyl alcohol in the range of up to 3 wt. % of the composition;

[0058] • the solvent being a mixture of propylene glycol in the range of 62 to 70 wt. % of the composition; and polyether comprising propyleneoxy units, optionally copolymerized with ethyleneoxy units with an ethyleneoxy : propyleneoxy ratio of 80:20 to 0: 100, in the range of up to 5 wt. % of the composition; and

[0059] • the stabiliser being a mixture of: fumed silica in the range of up to 1 wt. % of the composition; and amorphous silica in the range of 4 to 6 wt. % of the composition.

[0060] The composition may also comprise active substances, which improve the properties of the seed, which may be nutrients such as fertilizers, vitamins, micronutrients, macronutrients, fungal spores, bacterial spores, humectants, wetting agents, pesticides such as insecticides, fungicides and herbicides, growth regulators or biostimulants, soil microorganisms in the range of up to 10 wt. % of the composition.

[0061] The seed with the present composition achieves higher germination and emergence of crops compared to untreated seeds, binding the soil moisture and the necessary nutrients directly to the seed and then releasing them in times of scarcity. The result is higher hectare yield, higher biomass production, plant resistance to pests and higher survival rates for young plants. The result is also the efficiency of used raw materials (SAP or fertilizers). The present invention encompasses the development of a superabsorbent-based composition formulation suitable for hydrostimulatory coating of seeds and a method of coating the seeds with this composition.

[0062] In particular, the present invention regulates the time required to coat the seed, reduces the amount of ingredients required, and ensures a more even distribution of the ingredients.

[0063] The use of superabsorbents to coat the seeds gives the possibility to ensure higher germination and followed by growth of green matter in order to achieve higher yields. However, superabsorbents must be applied very homogeneously to the seed surface in order to maximize their effectiveness. The application of superabsorbents for seed coating is most desirable for planting in semi-dry and dry areas.

[0064] The main innovation of the present invention, which obviates most of the drawbacks of the prior art, is the use of a stable, liquid continuous phase as the carrier in which SAP is dispersed, as well as the other components that the composition comprises. The stable, liquid continuous phase with the carrier function is based on polyether, glycols, glycol ethers, aromatic alcohols or their combination, in addition to the carrier function and the continuous liquid medium, it has the task of uniform distribution of SAP particles in composition and, therefore, on the seeds after coating. The composition is non-flammable due to use of non-flammable solvents, and non-aqueous due to the absence of water. The composition is stable and ensures controllable swelling of the SAP only when it is contacted with a sufficient amount of water, i. e. after being coated on a seed and after contacting the seed with water (such as when irrigating a planted seed).

[0065] The liquid continuous phase of the composition allows to evenly wet the entire surface of the seed, thus solving the problem of homogeneity of SAP application. Unlike SAP dust particles without a liquid continuous phase, it is able to efficiently get into all the uneven parts and creases while the surface coverage with SAP is uniform at all points of the seed surface. The homogeneity of the coating is also when comparing the individual seeds in the batch as well as between the different batches.

[0066] In addition to ensuring even seed coverage with SAP, reliable control of the application rate of SAP is ensured by varying the SAP concentration in the composition, or by changing the SAP particle size in the composition, respectively. This always ensures that the optimum amount of SAP is applied to the seed, which results in a uniform germination and emergence dynamics for all seeds of the seed unit and thus ultimately a balanced stand. A balanced stand is the way to higher yield.

[0067] An important aspect of the present invention is the superabsorbent content of 20 to 35 wt. % of the composition. Too high an amount of the superabsorbent on the seed surface results in seed suffocation, high water uptake in the immediate vicinity of the seed, thereby preventing sufficient oxygen access and removal of germinated seed metabolites. Also, the superabsorbent may not be sufficiently covered by the adhesive and the superabsorbent will thus remain exposed, resulting in higher hygroscopicity, air humidity absorption, agglomeration, and individual seed and dustiness bonding. Sticky seed cannot be processed technologically, transported or sieved without problems. In addition, increased dust levels do not meet the required dust standard. Conversely, too low an amount of the superabsorbent on the surface of the seed, especially in dry areas, leads to a lack of moisture, low seed germination and plant emergence. Low superabsorbent compositions on the seed surface are known in the art and have the disadvantages mentioned above. Non-homogeneous or varying amount of superabsorbent deposited on the seed results in an uneven plant growth.

[0068] The present invention simplifies the seed treatment process, since it is not necessary to pre-wet the seed or to apply an adhesive layerthereon, but due to the incorporated adhesive component (e.g. PVAc, PVA) in the composition, dry seed can also be treated directly without pre-treatment. Thus, the time required for seed treatment is saved and the application of this method is expanded. At the same time, the adhesive component also functions as a film-forming component, smoothing the surface of the treated seed. Thus, the SAP attachment is stable and at the same time the SAP particles become a monolithic part of the coating without significantly projecting SAP particles, eliminating the problem of unstable SAP attachment to the seed surface, which also eliminates the problem of seed flow properties as the treated seeds do not get stuck.

[0069] After seed treatment, SAP particles are protected by a film-forming component (e.g., PVAc, PVA) from air humidity, thereby eliminating the problem of high susceptibility of SAP to air humidity, and subsequently bonding the treated seeds to each other and forming clumps.

[0070] An important aspect of the present invention is the content of the non-aqueous, non-flammable solvent in the range of 40 to 80 wt. % of the composition. If the non-aqueous solvent contains water (i. e. a wet solvent comprising substantially more than 1 wt. % of water with respect to the solvent), water is absorbed by the superabsorbent, the superabsorbent prematurely swells, agglomeration forms and individual seeds stick together, which is a technological obstacle to seed processing. Too high a concentration of the non-aqueous solvent causes premature swelling of the SAP and has an adverse effect on the seed due to the biological processes occurring during germination as well as the increased cost of work safety conditions. The non-aqueous solvent also ensures non-flammability of the composition.

[0071] A preferred aspect of the present invention is the content of the adhesive in the range of up to 5 wt. % of the composition. Too high an amount of adhesive prevents seed germination because the seed spends too much starter nutrients and energy to break through the adhesive layer, with not enough left for further growth leading to plant death.

[0072] An important aspect of the present invention is the content of the stabiliser in the range of up to 15 wt. % of the composition. The stabiliser prevents the SAP from premature swelling in the solvent, thus ensuring long-term stability. The stabiliser can be graphite, talc, zeolite, clays (e. g. mica), fumed silica, amorphous silica, sodium sulphate, salts of fatty acids (e. g. calcium or magnesium stearate), molybdenum disulphide, polytetrafluoroethylene, polypropylene or a mixture thereof, preferably a mixture of fumed silica and amorphous silica in the ratio of 1:20 to 20: 1, preferably 1: 15 to 1:8, e. g. 1: 10.

[0073] The lubricant and rheology-modifying additives of the composition, such as talc, fumed silica, amorphous silica (but other examples can also be graphite, zeolite, clays (e. g. mica), sodium sulphate, salts of fatty acids (e. g. calcium or magnesium stearate), molybdenum disulphide, polytetrafluoroethylene, polypropylene or a mixture thereof), also have a beneficial effect on the rheological properties of the composition (such as optimal viscosity) and treated seeds (such as optimal friction). They also counteract the mutual bonding of the seeds and the formation of clumps, especially after evaporation of the volatile components of the composition and prevent premature swelling of SAP in a liquid phase.

[0074] A preferred aspect of the present invention is the content of lubricant in the range of up to 15 wt. % of the composition and the content of rheology-modifying additive in the range of up to 12 wt. % of the composition. Too high an amount of lubricant additives leads to an incomplete film on the seed surface and to higher dustiness. Similarly, too high an amount of rheology-modifying additives leads to higher dustiness and decrease in composition viscosity, which complicates its application. Conversely, too low an amount of lubricant and rheology-modifying additives leads to the formation of agglomerates from individual seeds, unacceptable flow properties and to the formation of electric charge that promotes the aggregation of the seeds into agglomerates.

[0075] Furthermore, it is important to note that the contents of the individual components are the result of longterm testing (min. 3-year cycles) in real conditions (farms, fields in different climatic conditions) and in statistically relevant quantities. The stated contents of the components in the present composition are a compromise of optimal seed physiology and optimal processing (composition preparation, storage, composition application to seed, seed drying, flow properties).

[0076] SAP dosing in the form of a composition allows the full use of seed dressing devices, as opposed to methods, where it was not possible to use liquid dosing equipment for SAP dosing purposes. The SAP dosing in the form of the composition accelerates the seed treatment process and thus makes it possible to use any seed dressing device with a liquid dosing device, without the need to equip the liquid dosing device with additional components and to the operator to be exposed to the potential health risks.

[0077] The dispensing of SAP in the form of the composition also allows the use of continuous seed dressing devices.

[0078] The liquid continuous phase of the composition can also be used as a carrier for active substances (nutrients, fertilizers, vitamins, micronutrients, macronutrients, fungal spores, bacterial spores, minerals, inoculants, humectants, pesticides such as insecticides, fungicides, herbicides, biocides and biopesticides, biofertilizers, growth regulators or biostimulants and the like), preferably in the amount of up to 10 wt. % of the composition, which after evaporation of the volatile components become part of the seed film formed, and also as an anchoring agent. The function of anchoring the seed in the substrate (in the ground) is to penetrate the formed gel around the seed into the substrate capillaries that is in direct contact with the seeds. The resulting bond of seed to the substrate prevents the seed from being forced out by the roots out of the soil, resulting in slowing down the root growth. The anchoring also prevents the seed from being forced out of the ground or towards the surface. The anchoring of the seed results in a faster root growth in depth, thus providing faster access to the water source. Another benefit of this in-depth stabilization is that the seed emerges more evenly, which ensures a more even crop. Uniform vegetation has a higher yield.

[0079] Examples of the active agents useful in the present composition include, but are not limited to nutrients, fertilizers, vitamins, micronutrients, macronutrients, minerals, inoculants, humectants, pesticides such as insecticides, fungicides, herbicides, biocides and biopesticides, biofertilizers, growth regulators, biostimulants, fungal spores, bacterial spores and soil microorganisms. Nutrients, micronutrients, macronutrients and minerals are substances providing the necessary nutrients for plant growth and life and may be selected from the group comprising nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, boron, copper, iron, chloride, manganese, molybdenum, and zinc. Fertilizers are plant nutrients and can be selected from the group comprising nitrogen, phosphorus and potassium fertilizers, combinations thereof and organic fertilizers. Biofertilizers are a subset of fertilizers and may include microorganisms of the genera Rhizobium, Azotobacterium, Azospirillum, blue-green algae or phosphate-dissolving bacteria. Vitamins may include B, C and E vitamins. The inoculants are growth promoting microorganisms and may be selected from the group comprising Rhizobium, Agrobacterium, and mycorrhizal fungi, e.g. of the genus Glomeromycota and soil microorganisms such as Trichoderma, Aspergillus and the like . Humectants are substances that wet the surface and form a so-called conductive zone in the soil and include e.g. surfactants, hydrophilic chains, etc. Pesticides are substances intended to kill insects or other pests damaging cultivated plants and may be selected from the group comprising organophosphate pesticides, carbamate pesticides (e.g., thiram), organochlorine insecticides, pyrethroid pesticides, and microbial pesticides. Biopesticides are a subset of pesticides and may include microbial biopesticides, e.g. microbes of the genera Bacillus, Agrobacterium, Azospirillum, Bradyrhizobium, Paenibacillus, Rhizobium and Enterobacter, genus of fungi Trichoderma, Paecilomyces, Glomus or metabolites produced by these microorganisms, e.g. siderophores, bacillibactin, antibiotics, enzymes, phytohormones, lipopeptides, antibacterial polyketides and fungicidal metabolites. Fungicides are fungal and mold killers and may be selected from the group comprising dimethomorph, mancozeb, tricyclazole, carbendazim, hexaconazole, metalaxyl, benomyl, diphenoconazole, propiconazole, kitazin, tebuconazole, copper (I) chloride trihydroxide, copper (I) hydroxide, tridemorph and propineb. Herbicides are substances intended to kill unwanted vegetation and weeds and may be selected from the group comprising phenoxy acids, benzoic acid, dinitroaniline, bipyridylium salts, substituted urea, and arsenic compounds.

[0080] Growth regulators include promoters and growth inhibitors, e.g. auxins, gibberellins, cytokinins (promoters) or abscisic acid (inhibitor). Biostimulants are substances enhancing nutrient efficiency, abiotic stress tolerance, and / or crop quality properties and may include biofertilizers, growth regulators, inoculants, fulvonic acids, humic acids, humines, protein hydrolysates, betaines (e.g., glycine-betaine), polyamines, extracts of seaweed and chitosan.

[0081] Another essential aspect of said contents of the individual components of the present composition is the resulting viscosity of the composition, which affects the wetting of the seed surface in the seed dressing device. A suitably selected viscosity makes it possible to utilize the current devices used for coating or seed treatment. If the viscosity was too high, the pumps and distribution discs in the device could not be used, and at the same time the seed surface would not be sufficiently and homogeneously wetted and hence coated. Thus, the viscosity also affects the amount that is retained on the seed surface.

[0082] As seeds, com, wheat and other cereal seeds such as barley, oats, rye, rice, sunflower seeds, rape seed, sugar beet, soybean, cotton, sorghum, fruit, vegetables, grass and other small seeds such as beans, peas, lentils, peanuts or rice can be used. The composition may also be applied to vegetable and fruit seeds, such as e.g. cucumber, tomato and the like.

[0083] It is an object of the present invention to achieve increased seed germination by SAP in dry and semidry areas, to improve flow properties in seed transport and seed application in order to increase SAP deposition efficiency on the seed, increase seed SAP uniformity, suppress formation of seed clumps during the coating process as well as after the coating process, to use the SAP as a carrier for the active substances, to use the SAP as a deep seed stabilizer. Moreover, the present invention is intended to solve the flammability of seed coating compositions with high amounts of flammable solvents, such as alcohols. The utilization of polyethers, glycols, glycol ethers, aromatic alcohols and their combinations in the present composition as a liquid phase allows to avoid the fast evaporation and accumulation of solvent in the coating system, which eliminates the risk of formation of explosive atmosphere.

[0084] A method of coating a seed with the superabsorbent-based composition according to the invention, comprises dosing of said composition for 5 to 25 seconds on the seed in a seed dressing device, then drying the coated seed, releasing the coated, dried seed from the seed dressing device for up to 120 seconds. The composition may be dosed in the amount of up to 15 wt. %, preferably from 1 to 10 wt. %, e.g. from 1 to 5 wt. % or from 0. 1 to 2.5 wt. % with regard to seed weight and type. The amount of the composition to be dosed is also dependent on the quality of the seed itself, in particular its purity, or dustiness, respectively. As dustiness increases, the dosage of the composition increases for all crops. At the same time, the risk of agglomerate formation due to dust also increases.

[0085] As the seeds are still slightly wet after coating, the drying step helps to improve the seed flowability and to remove residual water that can be absorbed on the seed in case of using hygroscopic solvents (e. g. glycols).

[0086] In a preferred embodiment of the method, the composition comprises the active substances as mentioned above.

[0087] Description of the Drawings

[0088] The invention will be further supported by the figures, where Fig. 1 shows germinated com plants of uncoated (far left) and coated (centre and right) seeds with the present composition and Fig. 2 illustrates the microphotographs of uniformly coated com and rape seeds using the present composition.

[0089] Exemplary Embodiments

[0090] The implementation of the present invention will be explained by means of examples. The preferred embodiment has no limiting effect on the scope of protection. The terms in singular and plural number used in the text of the application and in the claims are used interchangeably (e.g. adhesive - adhesives).

[0091] Example 1: Table 1 below shows exemplary compositions of the present composition for hydrostimulatory coating of sugar beet, com, wheat, rape seed, sorghum, soybean, barley, sunflower, pea, cotton, tomato and cucumber. Weight % are given relative to 100 % by weight of the resulting composition. Table 1. Exemplary compositions of the present composition on different types of seeds.

[0092] Example 2:

[0093] The method of coating the seeds with the present composition comprises dosing of a composition comprising a grafted starch backbone copolymer of potassium acrylate and acrylamide as a superabsorbent polymer, mixed with fumed silica as a stabiliser and rheology-modifying additive and amorphous silica as a stabiliser and lubricant additive (solid phase), added to a liquid phase comprising polyvinyl alcohol as an adhesive dissolved in propylene glycol as a solvent for 8 seconds onto com seeds in a seed dressing device, followed by releasing the coated and dried com seeds from the seed dressing device for 60 seconds. The result is the evenly coated com seeds that do not stick to other seeds. The wt. % of the components of the composition of Example 2 can be the compositions No. 1, 11 or 15 of Example 1 (com seed). Example 3:

[0094] The method of coating the seeds with the present composition comprises dosing of a composition comprising a grafted starch backbone copolymer of potassium acrylate and acrylamide as a superabsorbent polymer, polyvinyl acetate as an adhesive in a solution polyether as a solvent, and talc as a stabiliser, lubricant additive and rheology-modifying additive for 16 seconds onto wheat seeds previously coated with a pesticide (active agent) in a seed dressing device, followed by releasing the coated and dried wheat seeds from the seed dressing device for 60 seconds. The result is the evenly coated wheat seeds that do not stick to other seeds. The wt. % of the components of the composition of Example 3 can be the composition No. 2 of Example 1 (wheat seed).

[0095] The polyether can be a polypropylene glycol with a molecular weight between 400 and 2000 g / mol, such as those included in the US patent application US 2023200380 Al in examples 13, 14 or 15 specified in Table 2 of the US document. Alternatively, the polyether can be a copolymer of propyleneoxy and ethyleneoxy units with an ethyleneoxy : propyleneoxy ratio of 80:20 to 40: 100 and a molecular weight between 900 and 1500 g / mol, such as those included in the US patent application US 2023200380 Al in examples 10, 11, 12, 16 or 17 specified in Table 2 of the US document. Alternatively, the polyether can be mixture of said copolymer and said polypropylene glycol, such as those included in the US patent application US 2023200380 Al in examples 15+12, 15+10 or 15+14 specified in Table 4 of the US document.

[0096] In addition, the pesticide layer is protected by the layer of the present composition, which reduces dustiness and abrasion of the individual seeds. In this case, the pesticide is kept close to the seed in the space between the seed and coating, which significantly reduces leakage of pesticide into the environment and improves the pesticide uptake around the seed. This benefit can help to reduce the concentration of the applied pesticide almost twice . Moreover, the proposed coating can protect the seed from certain pathogens.

[0097] Example 4:

[0098] The method of coating the seeds with the present composition comprises dosing of a pesticide (active ingredient) onto rape seeds in a seed dressing device, immediately thereafter dosing of a composition comprising a grafted starch backbone copolymer of potassium acrylate and acrylamide as a superabsorbent polymer, polyvinyl acetate as an adhesive in a solution of polyether, and talc as a stabiliser, lubricant additive and rheology-modifying additive onto the rape seeds in a seed dressing device for 10 seconds, followed by releasing the coated and already dried rape seeds from the seed dressing device for 60-120 seconds. The result is a uniformly pesticide-treated and coated rape seeds that do not stick to other seeds. The polyether can be as specified in Example 3 above. The wt. % of the components of the composition of Example 4 can be the composition No. 3 of Example 1 (rape seed). The dosing of the pesticide (active substance) and the present composition was also reduced in one step without the need to release the seeds from the seed dressing device.

[0099] Example 5:

[0100] The method of coating the seeds with the present composition comprises dosing of a composition comprising a grafted starch backbone copolymer of potassium acrylate and acrylamide as a superabsorbent polymer, polyvinyl alcohol as an adhesive in a solution of propylene glycol and polyether (30: 1 by weight, when the polyether is used as specified in Example 3 above) as a solvent, optionally fumed silica as a stabiliser and rheology-modifying additive, amorphous silica as a stabiliser and lubricant additive and fungal spores (active agent) for 15 seconds onto wheat seeds in the seed dressing device, followed by releasing the coated and already dried wheat seeds from the seed dressing device for 60-120 seconds. The wt. % of the components of the composition of Example 5 can be the compositions No. 4 (without a rheology-modifying additive) or 12 (with a rheology-modifying additive) of Example 1 (sugar beet seed). The result is evenly biostimulant-treated and coated wheat seeds that do not stick to other seeds.

[0101] Example 6:

[0102] The method of coating the seeds with the present composition comprises dosing of a pesticide (active ingredient) onto sugar beet seeds in a seed dressing device, immediately thereafter dosing of a composition comprising a grafted starch backbone copolymer of potassium acrylate and acrylamide as a superabsorbent polymer, polyvinyl alcohol as an adhesive in a solution of benzyl alcohol as a solvent, optionally fumed silica as a stabiliser and rheology-modifying additive, and talc as a stabiliser, lubricant additive and rheology-modifying additive onto the sugar beet seeds in a seed dressing device for 10 seconds, followed by releasing the coated and already dried sugar beet seeds from the seed dressing device for 60-120 seconds. The result is a uniformly pesticide-treated and coated sugar beet seeds that do not stick to other seeds. The wt. % of the components of the composition of Example 6 can be the compositions No. 4 (without a rheology-modifying additive) or 12 (with a rheology-modifying additive) of Example 1 (sugar beet seed). The dosing of the pesticide (active substance) and the present composition was also reduced in one step without the need to release the seeds from the seed dressing device.

[0103] Example 7:

[0104] The method of coating the seeds with the present composition comprises dosing of a composition comprising a polyacrylic acid backbone polymer grafted with cellulose as a super-absorbent polymer, mixed with fumed silica as a stabiliser and rheology-modifying additive and amorphous silica as a stabiliser and lubricant additive (solid phase), added to a liquid phase comprising polyvinyl alcohol as an adhesive dissolved in propylene glycol as a solvent for 8 seconds onto sorghum seeds in a seed dressing device, followed by releasing the coated and dried sorghum seeds from the seed dressing device for 60 seconds. The result is the evenly coated sorghum seeds that do not stick to other seeds. The wt. % of the components of the composition of Example 7 can be the composition No. 5 of Example 1 (sorghum seed).

[0105] Example 8:

[0106] The method of coating the seeds with the present composition comprises dosing of a composition comprising a chitosan cross-linked with ethylene diamine tetraacetic acid-urea (EDTA-urea) adduct as a superabsorbent polymer, mixed with talc as a stabiliser, lubricant additive and rheology-modifying additive (solid phase), added to a liquid phase comprising polyvinyl acetate as an adhesive dissolved in propylene glycol as a solvent for 12 seconds onto soybean seeds in a seed dressing device, followed by releasing the coated and dried soybean seeds from the seed dressing device for 60 seconds. The result is the evenly coated soybean seeds that do not stick to other seeds. The wt. % of the components of the composition of Example 8 can be the composition No. 6 of Example 1 (soybean seed).

[0107] Example 9:

[0108] The method of coating the seeds with the present composition comprises dosing of a composition comprising a grafted carrageenan backbone copolymer of acrylic acid and 2-hydroxyethyl acrylate as a superabsorbent polymer, polyvinyl alcohol as an adhesive in a solution of diethylene glycol and polyether as a solvent, mixed with fumed silica as a stabiliser and rheology-modifying additive and amorphous silica as a stabiliser and lubricant additive (solid phase) for 16 seconds onto barley seeds previously coated with a pesticide (active agent) in a seed dressing device, followed by releasing the coated and dried barley seeds from the seed dressing device for 60 seconds. The result is the evenly coated barley seeds that do not stick to other seeds. The polyether can be as specified in Example 3 above. The wt. % of the components of the composition of Example 9 can be the composition No. 7 of Example 1 (barley seed).

[0109] Example 10:

[0110] The method of coating the seeds with the present composition comprises dosing of a pesticide (active ingredient) onto the sunflower seeds in a seed dressing device, immediately thereafter dosing of a composition comprising a grafted collagen backbone copolymer of acrylic acid and acrylamide as a superabsorbent polymer, polyvinyl acetate as an adhesive in a solution of mono ethylene glycol as a solvent and talc as a stabiliser and lubricant additive and fumed silica as a stabiliser and rheologymodifying agent onto the sunflower seeds in a seed dressing device for 10 seconds, followed by releasing the coated and already dried sunflower seeds from the seed dressing device for 60-120 seconds. The result is the uniformly pesticide-treated and coated sunflower seeds that do not stick to other seeds. The wt. % of the components of the composition of Example 10 can be the compositions No. 8 of Example 1 (sunflower seed). The dosing of the pesticide (active substance) and the present composition was also reduced in one step without the need to release the seeds from the seed dressing device.

[0111] Example 11:

[0112] The method of coating the seeds with the present composition comprises dosing of a composition comprising of a grafted gelatine backbone copolymer of acrylic acid and itaconic acid as a superabsorbent polymer, mixed with fumed silica as a stabiliser and lubricant additive (solid phase), added to a liquid phase comprising polyvinyl alcohol copolymerised with polyethylene oxide as an adhesive dissolved in a mixture of propylene glycol and benzyl alcohol (9: 1 by weight) as a solvent for 12 seconds onto pea seeds in a seed dressing device, followed by releasing the coated and dried pea seeds from the seed dressing device for 60 seconds. The result is the evenly coated pea seeds that do not stick to other seeds. The wt. % of the components of the composition of Example 11 can be the composition No. 9 of Example 1 (pea seed).

[0113] Example 12:

[0114] The method of coating the seeds with the present composition comprises dosing of a composition comprising a hydrolysed canola protein backbone polymer grafted with polyacrylic acid as a superabsorbent polymer, mixed with fumed silica as a stabiliser and rheology-modifying additive combined with talc (weight ratio of 1:5) as a stabiliser and lubricant additive, added to a liquid phase comprising partially hydrolysed polyvinyl acetate copolymerized with ethyleneoxy units as an adhesive dissolved in a mixture of propylene glycol and polyether (9: 1 by weight, when the polyether is used as specified in Example 3 above) as a solvent for 12 seconds onto cotton seeds in a seed dressing device, followed by releasing the coated and dried cotton seeds from the seed dressing device for 60 seconds. The result is the evenly coated cotton seeds that do not stick to other seeds. The wt. % of the components of the composition of Example 12 can be the composition No. 10 of Example 1 (cotton seed).

[0115] Example 13:

[0116] The method of coating the seeds with the present composition comprises dosing of a biological endophytic formulation (bio stimulant) onto the com seeds in a seed dressing device, immediately thereafter dosing of a composition comprising a polyacrylate / polyacrylamide copolymer as a superabsorbent polymer, polyvinyl alcohol as an adhesive in a mixture of propylene glycol and polyether (3 : 1 by weight, when the polyether is used as specified in Example 3 above) as a solvent and amorphous silica as a stabiliser and lubricant additive and fumed silica as a stabiliser and rheology-modifying agent onto the com seeds in a seed dressing device for 8 seconds, followed by releasing the coated and already dried com seeds from the seed dressing device for 60-120 seconds. The result is the uniformly endophyte-treated and coated com seeds that do not stick to other seeds. The wt. % of the components of the composition of Example 13 can be the compositions No. 1, 11 or 15 of Example 1 (com seed). The dosing of the endophytic formulation (active substance) and the present composition was also reduced in one step without the need to release the seeds from the seed dressing device.

[0117] Example 14:

[0118] The method of coating the seeds with the present composition comprises dosing of a composition comprising an alginate backbone polymer grafted with polyacrylic acid as a superabsorbent polymer, mixed with amorphous silica as a stabiliser and lubricant additive and fumed silica a stabiliser and rheology-modifying additive (solid phase), added to a liquid phase comprising partially hydrolysed polyvinyl acetate copolymerized with quaternary ammonium salt as an adhesive dissolved in a mixture of propylene glycol and polyether (19: 1 by weight, when the polyether is used as specified in Example 3 above) as a solvent for 15 seconds onto sugar beet seeds in a seed dressing device, followed by releasing the coated and dried sugar beet seeds from the seed dressing device for 60 seconds. The result is the evenly coated sugar beet seeds that do not stick to other seeds. The wt. % of the components of the composition of Example 14 can be the compositions No. 12 of Example 1 (sugar beet seed).

[0119] Example 15:

[0120] The method of coating the seeds with the present composition comprises dosing of a composition comprising a polyitaconic acid cross-linked with polyethylene glycol diacrylate as a superabsorbent polymer, mixed with amorphous silica as a stabiliser and lubricant additive and fumed silica a stabiliser and rheology-modifying additive (solid phase), added to a liquid phase comprising polyvinyl alcohol as an adhesive dissolved in diethylene glycol as a solvent for 20 seconds onto tomato seeds in a seed dressing device, followed by releasing the coated and dried tomato seeds from the seed dressing device for 60 seconds. The result is the evenly coated tomato seeds that do not stick to other seeds. The wt. % of the components of the composition of Example 15 can be the composition No. 13 of Example 1 (tomato seed).

[0121] Example 16:

[0122] The method of coating the seeds with the present composition comprises dosing of a composition comprising a neutralised polyglutamic acid (e. g. having potassium, calcium, and / or ammonium as the counterions) as a superabsorbent polymer, mixed with amorphous silica as a stabiliser and lubricant additive and fumed silica a stabiliser and rheology-modifying additive (solid phase), added to a liquid phase comprising polyvinyl alcohol copolymerised with polyethylene oxide as an adhesive dissolved in the mixture of diethylene glycol and propylene glycol (1:9 by weight) as a solvent for 20 seconds onto cucumber seeds in a seed dressing device, followed by releasing the coated and dried cucumber seeds from the seed dressing device for 60 seconds. The result is the evenly coated cucumber seeds that do not stick to other seeds. The wt. % of the components of the composition of Example 16 can be the composition No. 14 of Example 1 (cucumber seed).

[0123] Example 17:

[0124] The method of coating the seeds with the present composition comprises dosing of a composition comprising a grafted starch backbone copolymer of potassium acrylate and acrylamide as a superabsorbent polymer, mixed with fumed silica as a stabiliser and rheology-modifying additive and amorphous silica as a stabiliser and lubricant additive (solid phase), added to a liquid phase comprising a partially hydrolysed polyvinyl acetate (66% hydrolysis degree) as an adhesive dissolved in propylene glycol monopropyl ether as a solvent for 8 seconds onto com seeds in a seed dressing device, followed by releasing the coated and dried com seeds from the seed dressing device for 60 seconds. The result is the evenly coated com seeds that do not stick to other seeds. The wt. % of the components of the composition of Example 17 can be the compositions No. 1, 11 or 15 of Example 1 (com seed).

[0125] Example 18:

[0126] A comparison of the com seeds having a hydrostimulatory coating with the present composition and the com seeds without a hydrostimulatory coating at 2 different testing stations in the Slovak Republic exposed to different climatic conditions (A - Cifer, B - Borovce), see Table 2. Above-average dry conditions were recorded at testing station B, which was reflected in the highest yield (25%) compared to the control.

[0127] Table 2. Comparison of com seed yields with and without the present composition.

[0128] Example 19:

[0129] Mean values of germination and growth parameters of com seed coated with the present composition as compared to control uncoated seed, see Table 3. The present composition had a positive effect on all measured parameters. The seeds coated with the present composition achieved better germination, fewer abnormalities and pathologies in the germinated plants, and more above ground and underground biomass.

[0130] Table 3. Mean values of germination and growth parameters of com seeds.

[0131] Example 20:

[0132] Fig. 1 shows germinated com plants of uncoated (far left) and coated (centre and right) seeds with the present composition. Plants germinated from the coated seeds have a greater amount of biomass, a better developed root system and leafy parts compared to uncoated plants. Fig. 2 illustrates the uniform coating of com (left) and rape (right) seeds using the present composition.

[0133] Example 21:

[0134] The Heubach test is used to determine the amount of free-flowing dust and abrasion particles around the treated seed under defined mechanical stress conditions. The value recommended by the European Seed Treatment Assurance (ESTA) is 0.7-3.2 g particles / 100 000 seeds. In the case of the com seed coated with the present composition, a value of 0.0274 g particles / 100 000 seeds was reached, which is far below the recommended limit. The low dustiness and abrasion of seeds are particularly appreciated in terms of work safety (especially in the case of e.g. pesticide treatment) and the efficiency of the entire coating process, namely the amount of coating that remains on the seeds.

[0135] Industrial Applicability

[0136] The present invention is applicable to coating of seeds of agricultural and horticultural crops in order to improve germination and abiotic stress resistance, improve stand balance, accelerate water access to roots, stabilize seed position in the substrate and increase yields. It is also applicable to the coating of granular and microgranular fertilizers with the aim of binding the nutrients and substances comprised therein with subsequent sustained release.

Claims

PATENT CLAIMS1. A superabsorbent-based composition for hydrostimulatory coating of seeds, characterized in that it comprises: a. a superabsorbent polymer having a water absorption capacity of at least 50 times its weight, in the range of 20 to 35 wt. % of the composition; b. a non-aqueous, non-flammable solvent in the range of 40 to 80 wt. % of the composition; and c. a stabiliser for preventing premature swelling of the superabsorbent polymer in the solvent, in the range of up to 15 wt. % of the composition.

2. The composition according to claim 1, characterized in that the superabsorbent is in the form of a grafted polymer comprising: a starch, cellulose, lignin, chitosan, chitin, carrageenan, collagen, gelatine, alginate, polyacrylate, polyitaconate, polyglutamate, polyglycoside or xanthan backbone chain; and a polymer graft chain grafted on said backbone chain, wherein the polymer graft chain comprises any one of acrylate, acrylamide, acrylonitrile, or a copolymer thereof chosen from a copolymer of acrylate and acrylamide, a copolymer of acrylate and acrylonitrile, a copolymer of acrylamide and acrylonitrile, or a copolymer of acrylate, acrylamide and acrylonitrile.

3. The composition according to claim 2, characterized in that the superabsorbent is a grafted starch polymer comprising a starch backbone chain; and a copolymer of acrylate and acrylamide grafted on said starch backbone chain, preferably potassium acrylate.

4. The composition according to any one of the preceding claims, characterized in that it further comprises an adhesive for dispersion or dissolution in the solvent, wherein the composition comprises the adhesive in the range of up to 5 wt. % of the composition.

5. The composition according to claim 4, characterized in that the adhesive is polyvinyl acetate, a partially hydrolysed polyvinyl acetate, polyvinyl alcohol, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, polyvinylpyrrolidone, lignin sulphonate, acacia gum, modified starch or carbohydrate.

6. The composition according to claim 5, characterized in that between 30 and 70 % of the polyvinyl acetate is hydrolysed.

7. The composition according to claim 5 or 6, characterized in that the polyvinyl acetate or the partially hydrolysed polyvinyl acetate is copolymerized with ethyleneoxy units and / or quaternary ammonium salts.

8. The composition according to any one of the preceding claims, characterized in that the solvent is chosen from a polyether comprising oxypropylene and / or oxyethylene units; glycol; glycol ether; aromatic alcohol or a mixture thereof.

9. The composition according to claim 8, characterized in that the polyether comprises propyleneoxy units, optionally copolymerized with ethyleneoxy units with an ethyleneoxy : propyleneoxy ratio of 80:20 to 0: 100.

10. The composition according to claim 8 or 9, characterized in that the polyether has a molecular weight between 80 and 2000 g / mol, preferably between 400 and 2000 g / mol.

11. The composition according to any one claims 8 to 10, characterized in that it comprises polyether in the range of up to 10 wt. % of the composition.

12. The composition according to claim 8, characterized in that the glycol is ethylene glycol, propylene glycol, diethylene glycol or a mixture thereof.

13. The composition according to claim 8, characterized in that the aromatic alcohol is benzyl alcohol.

14. The composition according to any one of the preceding claims, characterized in that the stabiliser is a lubricant additive chosen from graphite, talc, zeolite, clays, fumed silica, amorphous silica, sodium sulphate, salts of fatty acids, molybdenum disulphide, polytetrafluoroethylene, polypropylene or a mixture thereof.

15. The composition according to any one of the preceding claims, characterized in that the stabiliser is a rheology-modifying additive in the range of up to 12 wt. % of the composition.

16. The composition according to claim 15, characterized in that the rheology-modifying additive is talc, fumed silica, amorphous silica, sodium sulphate or a mixture thereof.

17. The composition according to any one of the preceding claims, characterized in that the stabiliser is a mixture of fumed silica and amorphous silica in the ratio of 1 :20 to 20: 1, preferably 1: 15 to 1:8.

18. The composition according to any one of the preceding claims, characterized in that it comprises active substances for improving properties of the seed, wherein the active substances for improving properties of the seed are selected from the group comprising fertilizers, vitamins, micronutrients, macronutrients, fungal spores, bacterial spores, minerals, inoculants, humectants, insecticides, fungicides, herbicides, biocides, biopesticides, biofertilizers, growth regulators or biostimulants, in the range of up to 10 wt. % of the composition.

19. The composition according to any one of claims 1 to 18, characterized in that it comprises: a. the superabsorbent being a grafted starch polymer comprising a starch backbone chain; and a copolymer of potassium acrylate and acrylamide grafted on said starch backbone chain, in the range of 20 to 30 wt. % of the composition; b. the adhesive being polyvinyl alcohol in the range of up to 3 wt. % of the composition; c. the solvent being propylene glycol in the range of 65 to 70 wt. % of the composition; and d. the stabiliser being a mixture of: fumed silica in the range of up to 1 wt. % of the composition; and amorphous silica in the range of 4 to 6 wt. % of the composition.

20. The composition according to any one of claims 1 to 18, characterized in that it comprises: a. the superabsorbent being a grafted starch polymer comprising a starch backbone chain; and a copolymer of potassium acrylate and acrylamide grafted on said starch backbone chain, in the range of 20 to 30 wt. % of the composition; b. the adhesive being polyvinyl alcohol in the range of up to 3 wt. % of the composition; c. the solvent being a mixture of propylene glycol in the range of 62 to 70 wt. % of the composition; and polyether comprising propyleneoxy units, optionally copolymerized with ethyleneoxy units with an ethyleneoxy : propyleneoxy ratio of 80:20 to 0: 100, in the range of up to 5 wt. % of the composition; and d. the stabiliser being a mixture of: fumed silica in the range of up to 1 wt. % of the composition; and amorphous silica in the range of 4 to 6 wt. % of the composition.

21. A method of coating a seed with the composition according to claims 1 to 20, characterized in that it comprises dosing of the composition according to any one of claims 1 to 18 for 5 to 25 seconds onto the seed in a seed dressing device, followed by drying the coated seed and releasing the coated, dried seed from the seed dressing device for up to 120 seconds.

22. The method according to claim 21, characterized in that the composition is dosed in the amount of up to 15 wt. % with reference to the weight of the seed.

23. The method according to claim 21 or 22, characterized in that the composition is dosed onto the seed previously treated with at least one active substance chosen from a fertilizer, vitamin, micronutrient, macronutrient, fungal spores, bacterial spores, mineral, inoculant, humectant, pesticide, insecticide, herbicide, fungicide, biocide, biopesticide, biofertilizer, growth regulator or biostimulant.

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