SK1562023U1 - Suspension based on superabsorbents suitable for hydrostimulating seed coating and method of seed coating with this suspension - Google Patents

Abstract

A suspension based on superabsorbents suitable for hydrostimulating seed coating containing a superabsorbent in the form of a copolymer of acrylate and acrylamide in the range of 25 to 40% by weight. suspensions, adhesives dispersed or dissolved in a solution of water and isopropanol, while the dispersion or solution of adhesives contains water in the range of 0.1 to 8 wt.%. suspensions, isopropanol in the range of 45 to 55 wt.% suspensions and adhesives in the range of 1 to 10% wt. suspensions, further lubricating additives suitable for improving the flow properties of the seed in the range of 0.1 to 15 wt.%. suspension and an antistatic additive suitable for eliminating electric charge in the range of 0.1 to 5 wt.%. suspension. The method of coating the seed with this suspension includes dosing a suspension containing a superabsorbent, an adhesive in a solution of water and isopropanol, lubricating and antistatic additives for 5 to 20 seconds on the seed in the pickling device, then draining the coated seed from the pickling device in the range of 1 to 10 seconds and drying the coated seed .

Description

The field of technology

Suspension based on superabsorbents especially for hydrostimulating seed coating and method of seed coating with this suspension. The main use is in agriculture and horticulture. Superabsorbent (SAP = super absorbent polymer) is used to coat the seed together with active ingredients with the aim of binding water in the soil to achieve an increase in germination in the absence of water and subsequently to increase the yields of agricultural crops, respectively. in order to reduce the frequency of irrigation and reduce the evaporation of water from the soil. The additives used in combination with SAP will improve the flow properties (reduce friction and abrasion) between the seeds of the seed and reduce possible wear of the machine parts of the seed drills. The suspension can be used as a carrier of active substances and as a deep stabilizer.

Current state of the art

Agricultural production depends, among other things, on seed quality. The better the quality of the seed (with high germination, resistant to pests, able to efficiently use individual components of the soil such as nutrients and water), the greater the probability of higher yields. Several metabolic processes take place in the seed during germination. Germination time depends on seed quality, environmental factors (temperature, presence of water) and so on. However, the goal is to achieve optimal germination and defined growth of the plant even under unfavorable climatic conditions.

In recent years, the issue of lack of soil moisture during germination has come to the fore. In the past, the problem of seed germination in the absence of moisture was solved by various hydration techniques, which were supposed to ensure fast and optimal germination in order to help achieve stable production under suitable economic conditions. For this reason, the seed was treated with various techniques before planting.

An example of a technique used so far to improve seed germination is the so-called "priming (infiltration). This technique was developed by W. Heydecker et al. in 1974 and involves osmotic control of water supply to the seed using an aqueous solution of water-soluble polymers (polyethylene glycol, sodium polypropionate, etc.) or aqueous salt solutions (W. Heydecker, J. Higgins and R. L. Gulliver, 1973, Nature (London) 246 p.42-44; W. Heydecker, 1974, Univ. Nottingham Sch. Agr. Rep. 1973/1974:50-67; Zuo Weinenget al., 1987, Chinese Science Bulletin 32:1438).

Another technique is the so-called "drum priming. The mentioned technique was developed by H.R. Rowse in 1987 and consists of wetting the seed by spraying in a rotating drum, directly controlling the water weight without using another medium (GB 2192781 B).

The "solid matrix priming" technique developed by A.G. Taylor et al. in 1988 controls seed water supply using powdered material (Agro-Lig) as a medium (A.G. Taylor, D.S. Klein and T.H. Whitlow, 1988, Scientia Horticulturae 37 (1988) 1-11; US 4912874 A; EP 0309551 B1; WO 88/ 07318 A1).

Finally, another well-known technique is the so-called "matrix conditioning. A technique developed by AA Khan et al. in 1990 he controls the supply of water to the seed using water-soluble porous materials (MicroCel E, Zonolite) as a medium (A.A. Khan, H. Miura, J. Prusinski, I. Ilyas Matri-conditioning of seeds to improve emergence Proceedings National Symposium on Stand Establishment of Horticultural Crops, Minneapolis, MN Apr.46,1990).

These techniques moisten the seed before sowing. However, they also have certain disadvantages:

The priming technique is not suitable for large quantities at the commercial level. The drum priming technique is simple, but the problems are in the precise mechanical control to regulate the amount of water and also the technology.

The technique can treat the seeds in simple, slowly rotating devices, but the problem is the separation of the seeds after they have been treated.

In addition to the mentioned procedures, in recent years there have been works devoted to the use of superabsorbent substances, which bind water and then gradually release it to plants. Two techniques were developed:

- the first is the use of a superabsorbent when sowing into the soil, when the polymer is added to the sowing site together with the seed, which is based on a procedure where SAP is sprinkled all over the substrate (ground)

- the second method is the application of a superabsorbent on the surface of the seed and its subsequent sowing

Patent documents related to this technology include US 2004077498 A1, US 2008236037 A1, US 2010093535 A1, US 9169164 B2, US 9212245 B2, US 9238774 B2, US 2012258811 A1, US 2014298872 A 1 and US 2012277099 A1.

Originally, the listed substances were applied to the seed using a system of slowly rotating drums, dispensers and dried in a dryer (drum priming). The disadvantage was primarily the higher requirements for the amount of substances used, their uneven distribution and the duration of the process.

SK 156-2023 U1

In the current state of the art, it is possible to find methods where the superabsorbent (SAP) is applied to the seed in powder form. With various variations, these are methods where an adhesive is applied to the seed and then SAP is added (sprinkled) in powder form (CN 106471952 A), or the ability of SAP to stick to a wet surface is used (US 2012277099 A1), when the property is used SAP that it can very quickly and efficiently absorb water into its structure, thereby attaching to the surface of the seed, as long as the surface of the seed was previously wet. In both cases, SAP is dosed in powder form. In both cases, it is necessary that before dosing the SAP, the seed is coated with either an adhesive or a substance that contains a certain amount of water and leaves the surface of the seed suitably moist. In both cases, therefore, pretreatment is necessary, or one more operation, before dosing the powdered SAP.

Both mentioned cases bring several disadvantages. Most of these disadvantages arise from the powder form of SAP. By dosing powdered SAP, it is not possible to achieve homogeneous coverage of the seed. The inhomogeneity of coverage is within one seed, but also in the case of comparing seeds with each other, or between individual bets. Another disadvantage is that in the case of powdered SAP, the SAP particles do not adhere to the surface of the seed intensively enough and fall off during storage and sowing activities. This lack increases the consumption of SAP, or the efficiency of the coating process is reduced. An increase in SAP consumption is also caused by SAP particles that do not come into contact with the surface of the seed during the dosing process into the pickling device because they are sucked in by the suction device.

SAP particles attached to the surface by the mentioned methods result in a deterioration of the flow properties of the seed and may lead to jamming of the seed in sowing equipment, or in other operations where the seed is transported by sandblasting. At the same time, the SAP particles anchored in this way are very sensitive to air humidity, which causes the stickiness of the SAP, and therefore also the sticking of the seeds to each other, which brings problems during storage, transport, but also during the sowing itself.

A significant disadvantage is that in the mentioned methods, the SAP dosing itself must be preceded by a seed pretreatment operation, so that the SAP particles can stick to the surface. Such a limitation brings a further reduction in efficiency with respect to the time required for pre-treatment.

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 impact if too much SAP is attached to the seed, or no effect if too little SAP sticks to the seed. Different amounts of entrapped SAP can result in different emergence dynamics and later different developed plants, which can reduce overall yield.

From the point of view of health protection, the mentioned methods bring complications, as very small particles of SAP get into the air, which worsens the working conditions. SAP particles can enter the air during the dosing of SAP into the pickling equipment, further during the discharge of the batch of already treated seed, as well as during the subsequent processing of the treated seed.

The technological disadvantage is the limited possibilities of using pickling equipment. As a priority, pickling plants are equipped with automatic devices for dosing liquid substances, but this option cannot be used for dosing SAP in powder form. For the dosing of powder materials, the pickling device must be supplemented with a dosing device for powder materials, which brings additional costs. The application of powder SAP in pickling plants, where there are no dosing devices for powder materials, is not possible. In the mentioned methods, or the method also requires, after the application of SAP, the dosing of Singulating substances (Ss), also in powder form, which requires an additional dosing device for powder materials, and therefore additional costs.

The use of methods in continuous pickling facilities would also be very problematic, or not possible.

International patent application WO 2005059023 A1 describes a suspension based on superabsorbents suitable for seed coating, comprising a superabsorbent, an adhesive dispersed or dissolved, preferably in an aqueous solution, and a bioactive, growth-stimulating additive. The superabsorbent is a grafted copolymer of starch (copolymer backbone) and e.g. acrylonitrile, acrylic acid or acrylamide (grafts). The suspension is applied to the seeds in an aqueous solution, which causes premature absorption of water by the superabsorbent during the application process, sticking and aggregation of individual treated seeds and clogging of sowing devices.

European patent EP 4007796 B1 describes a suspension based on superabsorbents suitable for hydrostimulating seed coating and a method of seed coating with said suspension. Said suspension includes a superabsorbent in the form of a copolymer of acrylate (eg potassium acrylate) and acrylamide in the range of 25 to 40% by weight. suspensions; adhesives dispersed or dissolved in a solution of water and ethanol and/or water and isopropanol, while the suspension contains adhesives in the range of 1 to 10 wt.%. suspension, water in the range of 0.1 to 8 wt.% suspension, and ethanol or isopropanol in the range of 40 to 70 wt.%. suspensions; lubricating

SK 156-2023 U1 additives suitable for improving the flow properties of the seed in the range of 0.1 to 15% by weight. suspensions; and an antistatic additive suitable for eliminating electric charge in the range of 0.1 to 5 wt.%. suspension. The mentioned method of coating the seed with the mentioned suspension includes dosing a suspension containing a superabsorbent, an adhesive in a solution of water and ethanol or water and isopropanol, lubricating and antistatic additives for 5 to 20 seconds on the seed in the pickling device, then draining the coated seed from the pickling device in the range of 1 to 10 seconds and drying the coated seed. Specific alcohol content in the range of 46.4 to 61.9% by weight. is given in example 1 only for ethanol, for which it is difficult to ensure sufficient purity at low cost.

International patent application WO 0166668 A2 describes a composition suitable for seed coating, including sodium polyacrylate superabsorbent in the amount of 0.3% by weight, fertilizer (active substance) in the amount of 1.2% by weight, polyethylene glycol 1450 in the amount of 23.5% by weight. and ethanol in the amount of 75% by weight. This composition was applied to the surface of Pickseed™ grass seed. Another described composition suitable for seed coating includes sodium polyacrylate superabsorbent in the amount of 4.4% by weight, fertilizer (active substance) in the amount of 15.6% by weight, polyethylene glycol 1450 in the amount of 30% by weight. and ethanol in the amount of 50% wt. This composition was applied to the surface of the rice seed in a ratio of 3.3:1 (seed:composition). Polyethylene glycol is mainly used in the composition as a lubricant additive and component that ensures better compatibility of other polymers with each other, but not as an adhesive or film-forming substance. The disadvantage is also the use of sodium salt of polyacrylate, which salinizes the soil with the addition of sodium cations.

In Chen, Junwu et al. (Swelling behaviors of polyacrylate superabsorbent in the mixtures of water and hydrophilic solvents) describes the behavior of polyacrylate superabsorbents (sodium polyacrylate) in a mixture of water and hydrophilic solvents (e.g. 20%, 40% and 60% methanol or ethanol). The balance of water absorption by the superabsorbent was determined in 10 min. and 48 h., while the authors came to the conclusion that the addition of a solvent with a low polarity fraction (methanol, ethanol) significantly reduces the absorption capacity of the superabsorbent, especially in a short time scale. The publication discusses in detail only sodium polyacrylate, but not its copolymers or polyacrylates with other counterions.

In You, Ying-Cai et al. (Synthesis and swelling behavior of crosslinked copolymers of neutralized maleic anhydride with other monomers) describes the behavior of a copolymer of maleic anhydride and acrylamide and a copolymer of maleic anhydride, acrylamide and hydroxyethyl methacrylate with N,N'-methylenebisacrylamide as a cross-linking 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 nonionic (OH, CONH2) and ionic functional groups (COOK). An excess of ionic functional groups causes an increase in the hydrophilicity and absorption capacity of the copolymer, while an excess of nonionic groups decreases the absorption capacity. A clear trend is a decrease in the absorption capacity of the mentioned copolymers with increasing concentration of alcohol in the aqueous solution (20%, 40% and 60%), while ethanol shows the largest decrease in absorption capacity of all tested alcohols. The disadvantage of maleic anhydride, due to two carboxyl groups within one monomer unit, is higher sensitivity to polyvalent ions (2+, 3+) found in the soil (mainly Ca ²⁺ , Mg ²⁺ , Al ³⁺ ), stronger intramolecular interaction in within one polymer chain, more intensive flocculation between different polymer chains, and too strong (even irreversible) anchoring of monovalent ions (Na ⁺ , K ⁺ ).

International patent application WO 2013158284 A1 describes a method of reducing dustiness when sowing seeds using a lubricating component applied to the seed with a layer of active substances (pesticides, etc.). The lubricating component includes waxes of synthetic, vegetable and/or animal origin (eg polypropylene wax), and is characterized by lower dustiness of the seed than in the case of using talc or graphite. The lubricating component does not include any superabsorbent that would increase the absorption capacity, or at all ensure the absorption of water in this layer.

International patent application WO 2007103076 A1 describes a seed coating composition for better binding of a bioactive component (e.g. insecticide, fungicide), while also improving the flow properties of coated seeds during transport and sowing. This composition includes an adhesive (eg polyvinyl acetate or polyacrylate), a wax (eg natural, mineral or synthetic wax), a pigment (eg mica coated with titanium dioxide) and a stabilizer (suspending agent, humectant, biocide). The composition is wet applied to the seed in an aqueous solution, which in the case of polyacrylate (although in the function of an adhesive) can cause premature absorption of water even before sowing into the soil.

American patent application US 2015267063 A1 describes a seed coating composition comprising an antistatic or electrically conductive additive, e.g. allotropic modification of carbon (e.g. graphite) or electrically conductive polymer.

In the publication Black et al. the use of graphite and talc to improve the flow properties of the seed is described.

A review by Wissler (Journal of Power Sources 156 (2006) 142-150) describes various functional and structural properties of generic graphites and their specific types, such as flake graphite.

SK 156-2023 U1

Slovak utility model application SK 50110-2016 U1 and Slovak patent application SK 50069-2016 A3 describe a combination of substances (coating mixture) containing a superabsorbent (polyacrylamide, polyacrylate or starch copolymers) and an adhesive solution in a mixture of water and ethanol, and preferably lubricating additives and biological active substances. Superabsorbent present and applied to the seed separately in the dry state, which can increase dustiness, abrasion of the seed surface and uneven surface of the superabsorbent layer. The content of the mixture of water and ethanol is adjusted to dissolve the adhesive (30 to 50% by weight of the adhesive solution), while the indicated amount of ethanol (20 to 40% by weight of the adhesive solution) and water (10 to 50% by weight of the adhesive solution) would in the process application could cause premature absorption of water by the superabsorbent. Next, the method of coating the seeds with this combination is described in two steps, where first the adhesive solution is applied to the seed, and only in the subsequent step the superabsorbent in a dry state.

US Patent Application US 2016219871 A1 describes seed treatment using polymeric hydrogels capable of absorbing water to improve seed germination in low humidity environments. Seed treatments based on cross-linked potassium polyacrylate (BountiGel™ hydrogel from mOasis Inc.) are described and exemplified on grass, corn and broccoli seeds. This hydrogel is applied to the seeds in a rotary seed coating machine (e.g. Aginnovation Rotary-6 seed machine) in a sequential manner in powder formulation 1 after the pre-coating step with adhesive solution A. After coating the seed with powder formulation 1, the seed is additionally coated with adhesive solution B and by powder formulation 2, i.e. in the order A ^ 1 ^ A ^ 1 ^ B ^ 2. In total, the entire composition is applied to the seed in the amount of 7.5 wt. %. The solution of adhesive A contains 10 to 20% vol. of polyvinylpyrrolidone PVP40 in dichloromethane. Powder formulation 1 contains 5 g of cross-linked potassium polyacrylate and 5 g of powdered talc. Adhesive solution B contains 20% vol. of polyvinyl acetate in dichloromethane. Powder formulation 2 contains 1 g of powdered potato starch and 9 g of powdered talc. Next, a method of coating seeds in a rotary seed coating machine is described and examples thereof are given for grass, corn and broccoli seeds. In addition, the seed coating composition may contain an active ingredient to improve the properties of the seeds, e.g. nutrient (N, NO3 ^- , K, P, Mg, Ca), fertilizer, pH regulating agent, herbicide, pesticide or fungicide.

International patent application WO 8501736 A1 describes a water absorbent seed coating composition comprising finely dispersed polyacrylate (unspecified counterion), finely ground polyacrylamide and finely ground graphite as a sticker. Polyacrylate and polyacrylamide form an “intimate mixture, but not a copolymer. Nevertheless, polyacrylate can form a copolymer with grafted starch chains. Polyacrylate and polyacrylamide particles preferably do not exceed 1,000 pm, e.g. 60 pm for polyacrylate and 300 and 20 pm for polyacrylamide, graphite particles preferably do not exceed 200 pm, e.g. 10 to 20 pm. The composition also contains an active ingredient, i.e. j. fertilizer, insecticide, pesticide, fungicide or nitrogen-fixing bacteria. In a preferred embodiment, the composition contains 33.3% graphite (particle size 10 to 20 µm), 33.3% internally crosslinked polyacrylate copolymer with grafted starch chains (particle size 60 µm), 16.0% crosslinked polyacrylamide (particle size 300 µm) and 17.4% cross-linked polyacrylamide (20 µm particle size). The coating step is carried out either directly on the seed in a dry process (without specifying the number of steps) or in the soil before sowing in the form of a water slurry.

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 the 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 designated as active agent Balíte™ (C), potassium polyacrylate-polyacrylamide copolymer designated Hankeshu™ aquasorb (D) and sodium polyacrylate-polyacrylamide copolymer designated Zhengyuan™ aquasorb (E) . Ethylene cellulose (1.5% in absolute ethanol) was used as an adhesive and coated in solution before coating the seed with superabsorbent. A mixture of attapulgite clay (= hydrated magnesium-aluminum silicate) and talc was used as filler and lubricating additive in a ratio of 2:1. The content of the 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 effective superabsorbent due to the highest water sorption capacity, while the remaining components of the mixture were always attapulgite clay and talc in a ratio of 2:1. The seed coating step was carried out sequentially in a coating machine, with the adhesive being coated first in an ethanol solution, followed by coating of powdered remaining ingredients, which was repeated for 15 cycles.

American patent US 7504445 B2 describes an aqueous superabsorbent composition for coating seeds containing a copolymer of potassium or ammonium polyacrylate and polyacrylamide (PAM, e.g. designated as Flobond™), preferably with 10-40 mol. % polyacrylate in copolymer and NPK fertilizer and cellulose mulch. The resulting dose of superabsorbent is 0.01 - 0.1% by weight. seeds. The document discusses the replacement of sodium by potassium or ammonium cations as a result of soil salinization. Before coating the seeds, water is prepared

SK 156-2023 U1 solution of a copolymer of potassium or ammonium polyacrylate and polyacrylamide, to which NPK fertilizer, cellulose mulch and the seed itself are added (in that order). The suspension is stirred for 30 minutes. and then it is sprayed on the soil.

A publication by Dan Anderson, 2014 (available from https://www.agweb.com/article/talc_and_graphite_what_you_need_to_know_be fore_you_plant_NAA_Dan_Anderson, November 27, 2020) describes a composition containing talc (as an antistatic additive (as a lubricant)) and grease in a ratio of 80: 20 in order to improve the flow properties of the seeds and eliminate the electric charge in the seed planting equipment.Other active substances are possible in the mixture.

American patent application US 2019000075 A1 describes a superabsorbent-based suspension suitable for hydrostimulating seed coating, containing a superabsorbent in the form of a copolymer of sodium acrylate and acrylamide in the range of 5 to 60, preferably 15 to 35% by weight, binders and film-forming agents (such as PVP, PVAc, graphite) dispersed or dissolved in an aqueous solution, lubricant additives (such as graphite in a concentration of 67% by weight) suitable for improving the flow properties of seeds and other additives such as mineral or organic salts (potassium salts), dispersing organic polymers or biologically active substances to improve the characteristics of the seed.

International patent application WO 9103149 A1 describes a semi-solid matrix composition based on a superabsorbent suitable for hydrostimulating encapsulation of seeds, which contains a superabsorbent in the form of a copolymer of potassium acrylate and acrylamide in the range of 1 to 25% by weight. dry matrix, binders (such as PVA or PVP) in the range of 0 to 40 wt.% dry matrix and other additives such as peat, non-ionic surfactant and biologically active substances to improve the properties of the seed.

British patent application GB 1591415 A describes a dry particulate soil matrix mixture of soil and soil additives for improving water retention around the seed, comprising soil, a superabsorbent in the form of a copolymer of potassium acrylate and acrylamide, lubricating additives (such as graphite) suitable for improving the flow properties of seeds in the range 1 to 2% wt. and other additives such as soil conditioners, possibly plant growth agents such as water, organic alcohols or talc with no apparent specific purpose.

The essence of the technical solution

The goal of the technical solution is to provide an environmentally neutral composition with sufficient purity and low production costs, suitable for hydrostimulating seed coating, which will ensure water retention in the immediate vicinity of the sown seed, higher germination and emergence of plants, especially in dry conditions, and uniform growth. Furthermore, the composition should be manufacturable and applicable to the seed in a more efficient way than in the prior art, with regard to meeting strict agricultural, industrial and safety standards and with better mechanical properties of the coated seed (flow properties, dustiness, adhesion).

The mentioned shortcomings are largely eliminated by the presented suspension based on superabsorbents suitable for hydrostimulating seed coating, which contains a superabsorbent, adhesives dispersed or dissolved in a solution of water and isopropanol, lubricating additives suitable for improving the flow properties of the seed and an antistatic additive suitable for eliminating electric charge.

The superabsorbent, which is a copolymer of acrylate and acrylamide, is contained in the range of 25 to 40 wt.%. suspension. Preferably, the superabsorbent is a copolymer of potassium acrylate and acrylamide, whereby the potassium acrylate may be the result of partial or complete neutralization of monomeric acrylic acid. Individual monomers can form an alternating, random, block or graft structure of the copolymer, and they can be in a mutual ratio of monomer units, e.g. 25 : 75 to 75 : 25 (acrylate : acrylamide), e.g. 25 : 75, 30 : 70, 40 : 60, 50 : 50, 60 : 40, 70 : 30 or 75 : 25. During seed germination, the superabsorbent gradually degrades, while the acrylamide chains are degraded to ammonia, which together with potassium acrylate salt provides the seed with important biogenic elements and nutrients. In the case of using sodium salt, unwanted salinization of the soil occurs, which is one of the disadvantages of the current state of the art.

The suspension also contains adhesives that serve to fix SAP and auxiliary substances. At the same time, the adhesive component also fulfills the function of a film-forming component. Polyvinyl acetate, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, polyvinyl pyrrolidone, lignin sulfonate, gum arabic or carbohydrates can be used as adhesives. Advantageously, the adhesive is polyvinyl acetate, because as a compact and at the same time flexible polymer, it can form a thin and continuous film that closes the surface of the seed, thereby not exposing the superabsorbent to atmospheric moisture. In addition, polyvinyl acetate has a desirable degree of biodegradability on the seed. Too fast biodegradation of the adhesive layer could occur even before sowing the seed, while too slow

SK 156-2023 U1 biodegradation would not allow optimal plant growth. Adhesives are dispersed or dissolved in a solution of water and isopropanol, while the adhesive solution contains water in the range of 0.1 to 8% by weight. suspensions, isopropanol in the range of 45 to 55 wt.% suspensions and adhesive in the range of 1 to 10% wt. suspension. Isopropanol is commonly produced by hydration of propene or hydrogenation of acetone, followed by distillation and azeotropic distillation. Isopropanol can therefore be obtained in high purity at a low price, unlike ethanol, which either contains impurities while maintaining a low price (e.g. denaturant for the purpose of exemption from excise duty), or requires higher production costs while maintaining high purity.

Another component are lubricity additives - auxiliary substances that improve flow properties. The lubricating additive can be graphite, talc, molybdenum sulphide, polytetrafluoroethylene, polypropylene or their mixtures. Preferably, the lubricating additive is graphite and/or talc. The suspension contains lubricant additives in the range of 0.1 to 15% by weight. suspension.

The suspension also contains an antistatic additive in the range of 0.1 to 5% by weight. suspensions to eliminate electric charge. Preferably, the antistatic additive is flake graphite.

The suspension can also contain active substances that improve the properties of the seed, which can be nutrients such as fertilizers, vitamins, micronutrients, macronutrients, humectants, wetting agents, pesticides such as insecticides, fungicides and herbicides, or growth regulators, or biostimulants in the range of 0 ,1 to 10% wt. suspension.

The seed with the presented suspension achieves higher germination and emergence of crops compared to seeds not treated in this way, binding soil moisture and necessary nutrients directly to the seed and their subsequent release in times of shortage. The result is a higher yield per hectare, higher biomass production, plant resistance to pests and a higher survival rate of young plants. At the same time, the result is the efficiency of the input raw materials used (SAP, or fertilizers). The presented technical solution includes the development of a formula for a suspension based on superabsorbents suitable for hydrostimulating seed coating and a method of seed coating with this suspension.

The presented technical solution mainly adjusts the time required for coating the seed, the requirements for quantities of ingredients will be reduced, and a more uniform distribution of individual ingredients will be ensured.

The use of superabsorbents for seed coating gives possibilities in ensuring higher germination and consequently with the growth of green matter with the aim of achieving higher yields. However, superabsorbents must be applied to the surface of the seed very homogeneously in order for their effectiveness to be as high as possible. The application of superabsorbents for seed coating is most desirable when planting in semi-arid and arid regions.

The main innovation of the presented technical solution, which results in the elimination of most of the disadvantages of the current state of the art, is the use of a liquid continuous phase as a carrier in which the SAP is dispersed, as well as the other components that the suspension contains. The liquid continuous phase with the carrier function is based on isopropanol and, in addition to the carrier function and continuous liquid environment, has the task of temporarily blocking the ability of SAP to absorb water until the volatile components of the suspension evaporate.

The liquid continuous phase of the suspension makes it possible to evenly wet the entire surface of the seed, which also solves the problem of homogeneity of SAP application. Unlike dust particles, SAP without a liquid continuous phase can effectively penetrate all bumps and folds, while the surface coverage with SAP is uniform at all points on the seed surface. There is homogeneity of coverage even when comparing individual seeds within a batch, as well as between different batches.

In addition to ensuring uniform coverage of the seed with SAP, reliable control of the amount of SAP applied by changing the concentration of SAP in the suspension, or by changing the size of SAP particles in suspension. This always ensures that the optimal amount of SAP is applied to the seed, which results in ensuring the uniformity of the dynamics of germination and emergence for all the seeds of the sowing unit, and thus ultimately a balanced stand. An even growth is the way to a higher yield.

An important aspect of the presented technical solution is the superabsorbent content of 25 to 40% by weight. suspension. An excessively high amount of superabsorbent on the surface of the seed leads to suffocation of the seed, high absorption of water in the immediate vicinity of the seed, which prevents sufficient access of oxygen and removal of metabolites of the germinating seed. Insufficient coverage of the superabsorbent with the adhesive component can also occur, and the superabsorbent therefore remains exposed, which leads to higher hygroscopicity, absorption of air moisture, agglomeration and sticking of individual seeds and dust. Sticky seed cannot be technologically processed, transported without problems, or sown. In addition, increased dustiness does not meet the required dustiness standard. Conversely, too little amount of superabsorbent on the surface of the seed leads, especially in dry areas, to a lack of moisture, low seed germination and plant emergence. Compositions with a low superabsorbent content on the surface of the seed are known from the state of the art and have the above-mentioned disadvantages. In case of inhomogeneous or fluctuating amount of applied superabsorbent on the seed leads to uneven growth of the plant.

The presented technical solution simplifies the seed treatment process, as it is not necessary to moisten the seed in advance or to apply a layer of adhesive to it, but thanks to the incorporated adhesive component (e.g.

SK 156-2023 U1

PVAc) in suspension, it is possible to treat even dry seed directly without pretreatment, in contrast to current methods. As a result, the time required for seed treatment is saved and the possibilities of using this method are expanded. At the same time, the adhesive component also fulfills the function of a film-forming component, so in addition to sticking the SAP on the surface, it also ensures leveling, or smoothing the surface of the treated seed. Thus, the attachment of SAP is stable and at the same time the SAP particles become a uniform part of the coating without significantly protruding SAP particles, which eliminates the problem of unstable attachment of SAP on the surface of the seed and also eliminates the problem with the flow properties of the seed, since the treated seed does not get stuck during sanding.

After seed treatment, the SAP particles are protected by a film-forming component (e.g. PVAc) from atmospheric moisture, thereby eliminating the problem of high sensitivity of SAP to atmospheric moisture, and subsequent sticking of treated seeds to each other and formation of clusters.

An important aspect of the presented technical solution is the content of the dispersion or solution of adhesives containing water in the range of 0.1 to 8% by weight. suspensions, isopropanol in the range of 45 to 55 wt.% suspensions and adhesives in the range of 1 to 10% wt. suspension. An excessively high amount of adhesive prevents the seed from germinating, because to break through the adhesive layer, the seed spends too much starter nutrients and energy, which does not remain for further growth, which leads to the death of the plant. If the concentration of water is too high and the concentration of isopropanol is too low, water absorption by the superabsorbent, agglomeration and sticking of individual seeds occur, which is a technological obstacle in seed processing. Too high a concentration of isopropanol has an adverse effect on the seed with regard to the biological processes taking place during germination, as well as the increased costs of safety at work.

Other components of the suspension, namely talc and flake graphite, also have a beneficial effect on the flow properties of the seed. They also act against the mutual sticking of seeds and the formation of clusters, especially after the evaporation of the volatile components of the suspension. In addition, thanks to its ability to conduct electric current, graphite reduces the accumulated electric charge in the seed, which arises as a result of the friction of the seed during the coating process in the pickling equipment, but also partly during transport, or when spreading the seed. Reduction of the electric charge in the seed reduces the formation of clumps in the seed.

An important aspect of the presented technical solution is the content of lubricant additives of 0.1 to 15% by weight. suspensions and the content of antistatic additives 0.1 to 5 wt.% suspension. Too high a quantity of lubricating additives leads to a non-compact film on the surface of the seed and to higher dustiness. Similarly, too high an amount of antistatic additives leads to higher dustiness. On the contrary, too little amount of lubricating and antistatic additives leads to the formation of agglomerates from individual seeds, unacceptable flow properties and to the formation of an electric charge, which supports the clustering of seeds into agglomerates.

Furthermore, it is important to note that the listed contents of the individual components are the result of long-term 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 presented suspension are a compromise of optimal seed physiology and optimal processing (suspension preparation, storage, application of the suspension to the seed, seed drying, flow properties).

Dosing SAP in the form of a suspension enables the full use of pickling equipment, in contrast to current methods, when it was not possible to use liquid dosing equipment for the purpose of dosing SAP. By dosing SAP in the form of a suspension, the seed treatment process is accelerated, and thus it is possible to use any pickling device with a dosing device for liquids, without the need for further addition with a dosing device for powder materials.

Dosing of SAP in the form of a suspension also allows the use of continuous pickling equipment.

The liquid continuous phase of the suspension can also be used as a carrier for active substances (nutrients, fertilizers, vitamins, micronutrients, macronutrients, minerals, inoculants, humectants, pesticides such as insecticides, fungicides, herbicides, biocides and biopesticides, biofertilizers, growth regulators or biostimulants and the like), preferably in an amount of 0.1 to 10% by weight. suspensions that become part of the formed film on the seed after evaporation of the volatile components, and also as a depth stabilizer (anchoring agent). The function of anchoring the seed in the substrate (in the ground) consists in the penetration of the created gel around the seed, into the capillaries of the substrate, which is in direct contact with the seeds of the seed. The resulting connection of the seed with the substrate prevents the seed from being pushed out of the soil by the root, which results in slowing down the growth of the root in depth. Anchoring also prevents the seed from being pushed above the surface of the earth, or towards the surface. The result of anchoring the seed is faster root growth to depth, thus faster securing of access to the water source. Another benefit of this depth stabilization is that the seed emerges more evenly, which will ensure a more uniform growth. The uniformity of the growth has an impact on a higher yield.

Examples of active substances usable in the present suspension 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 or biostimulants.

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Nutrients, micronutrients, macronutrients and minerals are substances providing nutrients necessary for plant growth and life and can be selected from the group including nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, boron, copper, iron, chloride, manganese, molybdenum and zinc. Fertilizers are substances that supply nutrients to plants and can be selected from the group including nitrogen, phosphorus and potassium fertilizers, their combinations and organic fertilizers. Biofertilizers are a subgroup of fertilizers and may include microorganisms of the genus Rhizobium, Azotobacterium, Azospirillum, blue-green algae or phosphate-dissolving bacteria. Vitamins may include vitamins B, C and E. Inoculants are growth-promoting microorganisms and may be selected from the group consisting of microorganisms of the genus Rhizobium, Agrobacterium, and mycorrhizal fungi, e.g. of the genus Glomeromycota. Humectants are substances that wet the surface and create so-called conductive zone in the soil and include e.g. surfactants, hydrophilic chains, etc.

Pesticides and insecticides are substances intended to kill insects or other organisms damaging cultivated plants and can be selected from the group including organophosphate pesticides, carbamate pesticides (eg thiram), organochlorine insecticides, pyrethroid pesticides, and microbial pesticides. Biopesticides are a subgroup of pesticides and may include microbial biopesticides, e.g. microbes of the genus Bacillus, Trichoderma, Agrobacterium, Paecilomyces, Azospirillum, Glomus, Bradyrhizobium, Paenibacillus, Rhizobium and Enterobacter, or metabolites produced by these microbes, e.g. siderophores, bacillibactin, antibiotics, enzymes, phytochromones, lipopeptides, antibacterial polyketides and fungicidal metabolites. Fungicides are substances designed to kill fungi and molds and can be selected from the group including dimethomorph, mancozeb, tricyclazole, carbendazim, hexaconazole, metalaxyl, benomyl, difenoconazole, propiconazole, kitazine, tebuconazole, copper trihydroxide chloride, copper hydroxide, tridemorph and propineb. Herbicides are substances intended to kill unwanted vegetation and weeds and may be selected from the group including phenoxy acids, benzoic acid, dinitroaniline, bipyridyl salts, substituted ureas, and arsenic compounds.

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

Another important aspect of the listed contents of the individual components of the presented suspension is the resulting viscosity of the suspension, which affects the wetting of the seed surface in the pickling device. An appropriately chosen viscosity makes it possible to use the current equipment used for coating, or seed treatment. If the viscosity were too high, it would not be possible to use the pumps, pumps and distribution disks in the equipment, at the same time the surface of the seed would not be sufficiently and homogeneously wetted, and therefore also coated. Viscosity therefore also affects the amount that is captured on the surface of the seed.

The seeds of corn, wheat and other cereals such as barley, oats, rye, rice, sunflower seeds, rapeseed, sugar beet, soybean, cotton, sorghum, fruit, vegetable, grass and others can be used as seed for coating with the above suspension. small seeds such as beans, peas, lentils, peanuts or rice. The suspension can also be applied to vegetable and fruit seeds, such as cucumber, tomatoes, etc.

The aim of the presented technical solution is to achieve increased seed germination with the help of SAP in arid and semi-arid areas, to improve the flow properties during seed transport, as well as when applying the seed to the soil with the aim of increasing the efficiency of applying SAP to the seed, increasing the uniformity of the amount of SAP applied to the seed, suppressing the formation of clusters during the coating process as well as after the coating process, the use of SAP as a carrier for active substances, the use of SAP as a depth stabilizer of the seed.

The method of coating the seed with a suspension based on superabsorbents according to the technical solution includes dosing a suspension containing a superabsorbent, adhesive in a solution of water and isopropanol, lubricating and antistatic additives for 5 to 20 seconds on the seed in the pickling device, then draining the coated seed from the pickling device in the range of 1 to 10 seconds. The suspension is dosed in an amount of 0.1 to 15% by weight, preferably 1 to 10% by weight, e.g. 1 to 5% wt. or 1 to 2.5% wt. considering the weight and type of seed. The amount of dosed suspension also depends on the quality of the seed itself, specifically on its purity, or dustiness. With increasing dustiness, the dosage of the suspension increases for all crops. At the same time, the risk of agglomerate formation due to dust increases.

In a preferred embodiment of the seed coating method, the suspension contains active substances, as mentioned above.

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Overview of images on drawings

This technical solution will be clarified with the help of figures, where fig. 1 shows germinated maize plants from uncoated (left) and coated (right) seed with the present suspension.

Implementation examples

The implementation of the presented technical solution will be explained using implementation examples. The preferred embodiment has no limiting effect in terms of the scope of protection.

Example 1:

The following table 1 shows exemplary compositions of the present suspension suitable for hydrostimulating seed coating of soybean, sorghum, sugar beet, corn, wheat and rapeseed. % by weight are given with respect to 100% weight of the resulting suspension.

Seed SAP Water Isopropanol Adhesive Lubricant additive Antistatic additive [wt%] [wt%] [wt%] [wt%] [wt%] [wt%] Soy 36.0 2.4 46.4 8.0 6.2 1.0 Sorghum 39.5 2.1 49.7 7.0 0.8 0.9 Sugar beet 32.7 3.6 51.9 6.0 4.6 1,2 Sweet corn 30.0 4.0 47.6 7.9 9.0 1.5 Wheat 26.3 5.8 50.8 9.6 5.3 2,2 Rapeseed oil 28.4 4.5 53.6 3.8 5,6 4.1

Table 1. Exemplary compositions of the presented suspension on different types of seed

Example 2:

The method of coating the seed with the presented suspension includes dosing a suspension containing a copolymer of potassium acrylate and acrylamide, polyvinyl acetate in a solution of water and isopropanol, talc and flake graphite for 10 seconds on the wheat seed in the pickling device, then draining the coated wheat seed from the pickling device within 3 seconds. The seed coated with the suspension is subsequently dried. The result is evenly coated wheat seed that does not stick to each other.

Example 3:

The method of coating the seed with the presented suspension includes the dosing of a suspension containing a copolymer of potassium acrylate and acrylamide, polyvinyl acetate in a solution of water and isopropanol, polypropylene and flake graphite for 16 seconds onto the corn seed previously coated with a pesticide (active substance) in the pickling device, followed by the release of the coated wheat seed from the pickling device within 6 seconds. The seed coated with the suspension is subsequently dried. The result is evenly coated corn seed that does not stick to each other.

The layer of pesticide is additionally protected by a layer of the presented suspension, which reduces dustiness and abrasion of individual seeds.

Example 4:

The method of coating the seed with the presented suspension includes dosing the pesticide (active substance) on the oilseed rape seed in the pickling device, immediately after that dosing the suspension containing the copolymer of potassium acrylate and acrylamide, polyvinylpyrrolidone in a solution of water and isopropanol, talc and flake graphite for 5 seconds on the seed in the pickling equipment, followed by the release of coated rapeseed from the pickling equipment within 2 seconds. The seed coated with the suspension is subsequently dried. The result is uniformly pesticide-treated and coated canola seed that does not stick to each other. There was also a shortening of the dosage of the pesticide (active substance) and the presented suspension to one step without the need to drain the seed from the pickling device.

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Example 5:

The method of coating the seed with the presented suspension includes dosing a suspension containing a copolymer of potassium acrylate and acrylamide, polyvinyl acetate in a solution of water and isopropanol, talc, flake graphite and a biostimulant (active substance) for 15 seconds on the soybean seed in the pickling device, then releasing the coated soybean seed from the pickling device within 9 seconds. The seed coated with the suspension is subsequently dried. The result is uniformly biostimulated and coated soybean seeds that do not stick to each other.

Example 6:

Comparison of oilseed rape seed hydrostimulation coated with the presented suspension and oilseed rape seed without hydrostimulation coating at 3 different test stations in the Czech Republic exposed to different climatic conditions (A - Chlumec nad Cidlinou, B - Opava, C - Lužany u Preštic), see table 2. above-average dry conditions were recorded at test station B, which was also reflected in the highest yield (19%) compared to the control.

Test station A B C Coated seed 5.39 3.22 6,13 Uncoated seed 5.11 2.70 5.85 Increase in yield 5% 19% 5%

Table 2. Comparison of oilseed rape yields with and without the presented suspension.

Example 7:

Average values of germination and growth parameters of wheat seed coated with the presented suspension compared to the control coated seed, see table 3. The presented suspension had a positive effect on all monitored parameters. The seed coated with the presented suspension achieved better germination, fewer abnormalities and pathologies in the germinated plants and more above-ground and underground biomass.

Parameter Coated seed Uncoated seed Seed germination after 48 hours. [%] 94.17 83.33 Germination of seeds after 192 hours. [%] 97.50 93.75 Ungerminated seeds [%] 2.50 6.25 Abnormally germinated seeds [%] 1.25 2.15 Pathologies in germination [%] 3.75 8.40 Stem length [mm] 64.27 56,59 Number of roots [pcs/plant] 3.88 3.67 Root length [mm/plant] 278.48 262.48 Mass of biomass [mg/plant] 14.38 13.51

Table 3. Average values of wheat seed germination and growth parameters.

Example 8:

In fig. 1 shows germinated maize plants from uncoated (left) and coated (right) seeds with the present suspension. Plants germinated from coated seed have more biomass, have a better developed root system and leaf part compared to uncoated plants.

Example 9:

The Heubach test is used to determine the amount of free-flying dust and abrasion particles in the vicinity of treated seeds under defined mechanical load conditions. The value recommended by the European Seed Treatment Assurance Agency (ESTA) is 0.5 g particles/700,000 seeds. In the case of rape seed coated with the presented suspension, a value of 0.1783 g of particles/700,000 seeds was reached, which is a value below the recommended limit. Low dustiness and seed abrasion are valued especially from the point of view of work safety (especially in the case of e.g. pesticide treatment) and the efficiency of the entire application process, specifically the amount of the applied layer that remains on the seed.

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Industrial applicability

The presented technical solution can be used to coat the seed of agricultural and horticultural crops with the aim of improving germination, improving the evenness of the growth, accelerating the access of water to the roots, stabilizing the position of the seed in the substrate and increasing yields. It is also applicable to coating granulated and microgranulated fertilizers with the aim of binding nutrients and substances contained in them with subsequent gradual release.

Claims (13)

1. A suspension based on superabsorbents suitable for hydrostimulating seed coating, including a superabsorbent in the form of a copolymer of acrylate and acrylamide in the range of 25 to 40% by weight. suspensions; adhesives dispersed or dissolved in a solution of water and isopropanol, while the suspension contains adhesives in the range of 1 to 10 wt.%. suspension, and water in the range of 0.1 to 8 wt.%. suspensions; lubricating additives suitable for improving the flow properties of the seed in the range of 0.1 to 15% by weight. suspensions; and an antistatic additive suitable for eliminating electric charge in the range of 0.1 to 5 wt.%. suspension, characterized in that the suspension contains isopropanol in the range of 45 to 55 wt.%. suspension. 2. Suspension according to claim 1, characterized in that the superabsorbent is a copolymer of potassium acrylate and acrylamide. 3. Suspension according to claims 1 or 2, characterized in that the adhesive is polyvinyl acetate, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, lignin-sulfonate, gum arabic or carbohydrates. 4. Suspension according to claims 1, 2 or 3, characterized in that the lubricating additives are graphite, talc, molybdenum sulphide, polytetrafluoroethylene, polypropylene or their mixtures. 5. Suspension according to claims 1, 2, 3 or 4, characterized in that the antistatic additive is flake graphite. 6. Suspension according to any one of the preceding claims, characterized in that it contains active substances for improving the properties of the seed, while the active substances for improving the properties of the seed are selected from the group containing nutrients, fertilizers, vitamins, mmicronutrients and macronutrients, minerals, inoculants, humectants, pesticides such as insecticides, fungicides, herbicides, biocides and biopesticides, biofertilizers, growth regulators or biostimulants. 7. Suspension according to any one of claim 6, characterized in that it contains active substances for improving the properties of the seed in the range of 0.1 to 10% by weight. suspension. 8. Use of a suspension according to any one of claims 1 to 7, for coating seeds, which are mainly seeds of corn, wheat and other cereals, such as barley, oats, rye, rice, sunflower seeds, oilseed rape, sugar beet, soy, cotton, sorghum, chickpeas, fruits, vegetables, grasses and other small seeds such as beans, peas, lentils, groundnuts. 9. The method of coating the seed with a suspension according to claims 1 to 7, characterized by the fact that it includes the dosing of a suspension containing a superabsorbent, an adhesive in a solution of water and isopropanol, lubricating and antistatic additives for 5 to 20 seconds on the seed in the pickling device, then releasing the coated seed from pickling equipment in the range of 1 to 10 seconds and drying the coated seed. 10. The seed coating method according to claim 9, characterized in that the suspension is dosed in an amount of 0.1 to 15% by weight. seeds. 11. Method of seed coating according to claims 9 or 10, characterized in that the suspension is dosed to the seed previously treated with at least one active substance from the group including nutrient, fertilizer, vitamin, micronutrient and macronutrient, mineral, inoculant, humectant, pesticide, insecticide, herbicide, fungicide, biocide, biopesticide, biofertilizer, growth regulator or biostimulant. 12. The method of seed coating according to claims 9 or 10, characterized in that it includes the dosing of an active substance on the seed immediately before the dosing of the suspension, while the active substances for improving the properties of the seed are selected from the group containing nutrients, fertilizers, vitamins, micronutrients and macronutrients, minerals, inoculants, humectants, pesticides, insecticides, fungicides, herbicides, biocides, biopesticides, biofertilizers, growth regulators or biostimulants. 13. Seed coating method according to claims 9 or 10, characterized in that the suspension contains active substances selected from the group containing nutrients, fertilizers, vitamins, micronutrients and macronutrients, minerals, inoculants, humectants, pesticides, insecticides, fungicides, herbicides, biocides, biopesticides, biofertilizers, growth regulators or biostimulants.