Granular agricultural and horticultural composition and production method for granular agricultural and horticultural composition

Abstract

Provided is a granular agricultural and horticultural composition which hardly causes blocking. This granular agricultural and horticultural composition 1 comprises: a particle 2 having a biodegradable polyol on the surface thereof; and powders 3 at least parts of which are exposed from the surface of the particle 2. The powders 3 have an average particle diameter of 10-350 μm, and an SP value (δA) (cal / cm3)1 / 2, as calculated by the Fedors method at 25ºC, which is higher than the SP value (δB) (cal / cm3)1 / 2 of the biodegradable polyol and equal to or lower than δB+26 (cal / cm3)1 / 2.

Description

Granular agricultural and horticultural composition and method for producing the granular agricultural and horticultural composition

[0001] The present disclosure relates to a granular agricultural or horticultural composition. Specifically, the present disclosure relates to a granular composition for use in agriculture or horticulture. The present disclosure also relates to a method for producing a granular agricultural or horticultural composition. This application claims priority from Japanese Patent Application No. 2023-197757, filed November 21, 2023, the contents of which are incorporated herein by reference.

[0002] Liquid wood vinegar has been known as a functional additive for plants. Recently, biostimulants (also called biological stimulants) have been attracting attention as agricultural materials. These biostimulants utilize the natural power inherent in plants and their surrounding environments to positively affect plant health and stress tolerance.

[0003] For example, Patent Document 1 discloses an agent for improving the heat or salt tolerance of plants, containing acetic acid, a salt thereof, or a solvate thereof. Patent Document 1 proposes the use of a liquid composition, such as an aqueous solution of acetic acid. However, when such a liquid composition is sprayed on plants and the soil in which the plants are grown, there is a problem that the water-soluble acetic acid is washed away by rain. Furthermore, there is also a problem that acetic acid alone is too irritating to plants, making it impossible to make a highly concentrated aqueous solution of acetic acid. Therefore, in order to obtain the desired effect using the liquid composition disclosed in Patent Document 1, it was necessary to spray the liquid composition multiple times.

[0004] On the other hand, solid compositions other than liquid compositions such as aqueous acetic acid solutions are known. For example, Patent Document 2 discloses a solidified product of wood vinegar containing wood vinegar, a natural gelling agent, a polyhydric alcohol, an organic acid or its salt, an organic fertilizer, and water. Patent Document 3 discloses a soil conditioner obtained by impregnating pulverized rice husks with wood vinegar and rice vinegar. Patent Document 4 also discloses a sustained-release formulation comprising an adsorption carrier containing a biologically active substance and a sustained-release membrane. Patent Document 5 discloses a granular agricultural and horticultural composition in which the surface of a granular fertilizer is coated with a coating material A that is a biodegradable cellulose ester composition, or a mixture of a coating material B such as an olefin polymer and a coating material A.

[0005] International Publication No. 2020 / 130145 JP 8-59421 JP 2008-189647 JP 2005-515234 JP 11-116371

[0006] In order to solidify liquid components, chemicals such as gelling agents and binders are required, as in Patent Documents 2 and 3. However, when considering use as agricultural materials, there is a concern that various chemicals may remain in the soil, etc. Patent Documents 4 and 5 solve this problem. However, depending on the surface material of the granular composition, particles of the granular composition may adhere to each other (block) when they come into contact with each other. When the granular compositions block with each other, multiple granular compositions form aggregates, making them difficult to handle during use.

[0007] Therefore, an object of the present disclosure is to provide a granular agricultural and horticultural composition that is less likely to cause blocking. Another object of the present disclosure is to provide a method for producing a granular agricultural and horticultural composition that is less likely to cause blocking.

[0008] That is, the present disclosure provides a particle having a biodegradable polyol on its surface and a powder at least partly exposed from the particle surface, wherein the powder has an average particle diameter of 10 to 350 μm and an SP value (δ) at 25° C. calculated by the Fedors method. Ａ ) (cal / cm ３ ) １／２ is the SP value (δ Ｂ ) (cal / cm ３) １／２ higher than δ Ｂ +26 (cal / cm ３ ) １／２ A granular agricultural and horticultural composition is provided, which is:

[0009] The biodegradable polyol is preferably a water-soluble polyether polyol and / or a water-insoluble polyester polyol.

[0010] The particles may further have a biodegradable cellulose ester on the surface.

[0011] The biodegradable cellulose ester is preferably one or more selected from the group consisting of cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate.

[0012] The water-insoluble polyester polyol is preferably poly(ε-caprolactone).

[0013] The proportion of the powder is preferably 0.01 to 10% by mass relative to the total amount of the granular agricultural and horticultural composition.

[0014] The powder is preferably a biodegradable cellulose ester.

[0015] The biodegradable cellulose ester as the powder preferably contains cellulose acetate having an average degree of substitution of 2.2 to 2.5.

[0016] The particle preferably has a core-shell structure comprising a core layer and a shell layer covering the core layer, and the shell layer provides the surface of the particle.

[0017] The present disclosure also provides a method for producing a granular agricultural and horticultural composition having a core-shell structure with a shell layer containing a biodegradable polyol, wherein the core layer is coated with a resin composition containing a biodegradable polyol, and the core layer is coated with a resin composition having an average particle diameter of 10 to 350 μm and an SP value (δ) at 25° C. calculated by the Fedors method. Ａ ) (cal / cm ３ ) １／２ is the SP value (δ Ｂ) (cal / cm ３ ) １／２ higher than δ Ｂ +26 (cal / cm ３ ) １／２ The present invention provides a method for producing a granular agricultural and horticultural composition, comprising: adhering a powder as described below to the particles; and coating the particles to which the powder has been adhered with a resin composition containing a biodegradable polyol.

[0018] The granular agricultural and horticultural composition of the present disclosure is less likely to cause blocking. Therefore, the granular agricultural and horticultural composition of the present disclosure is less likely to form aggregates even when in contact with each other, and is easy to handle during use. Furthermore, the method for producing the granular agricultural and horticultural composition of the present disclosure is less likely to cause blocking.

[0019] 1 shows one embodiment of the granular agricultural and horticultural composition of the present disclosure, and 2 shows another embodiment of the granular agricultural and horticultural composition of the present disclosure.

[0020] [Granular Agricultural and Horticultural Composition] The granular agricultural and horticultural composition of the present disclosure (sometimes simply referred to as "agricultural and horticultural composition") comprises at least particles and a powder at least partially exposed from the surface of the particles. In this specification, a "granular agricultural and horticultural composition" is a granular (particulate) composition for agricultural and / or horticultural use. In this specification, "granular" means a solid particle at room temperature (20°C ± 5°C). In this disclosure, the granular material is not limited to spherical particles, but may be approximately spherical, flat, have a smooth surface, have an uneven surface, or a mixture thereof.

[0021] <Particles> The particles have a biodegradable polyol on the surface thereof, that is, the particles have a layer (surface layer) containing a biodegradable polyol on the surface thereof.

[0022] The particles may be particles composed of a single layer or particles composed of multiple layers. When the particles are composed of a single layer, the single layer corresponds to the surface layer. When the particles are composed of multiple layers, the layer located on the particle surface among the multiple layers corresponds to the surface layer. Examples of the particles composed of multiple layers include particles having a core-shell structure comprising a core layer and a shell layer covering the core layer. In this case, it is preferable that the shell layer provides the surface of the particle.

[0023] Figure 1 shows one embodiment of the agricultural and horticultural composition of the present disclosure. The agricultural and horticultural composition 1 shown in Figure 1 is granular and includes particles 2 and powder 3. At least a portion of the powder 3 is exposed from the surface of the particle 2. The powder 3 may be partially or completely exposed from the surface of the particle 2. In the agricultural and horticultural composition 1 shown in Figure 1, the particle 2 is composed of multiple layers, including a core layer 4 and a shell layer 5 that covers the core layer 4, and the shell layer 5 forms a surface layer with a plurality of powders 3 attached to its surface.

[0024] (Surface Layer) Biodegradable Polyol The surface layer contains at least a biodegradable polyol. Biodegradable polyols have a lower environmental impact than non-biodegradable synthetic polymers. Furthermore, biodegradable polyols are prone to blocking upon contact, but exposing powder on the particle surface can make blocking less likely to occur. The surface layer may contain only one type of biodegradable polyol, or two or more types.

[0025] Examples of the biodegradable polyol include polyether polyols such as polyethylene glycol, polyester polyethers, polysaccharides such as starch, etc. Among these, polyether polyols are preferred.

[0026] The polyester polyol may be a polyhydroxyalkanoic acid having, as a repeating unit, a structural unit formed by polycondensation of a hydroxyalkanoic acid, or a polymer having, as a repeating unit, a structural unit formed by dehydration condensation of a dicarboxylic acid and a diol.

[0027] Examples of the polyhydroxyalkanoic acid include polyglycolic acid, polylactic acid, poly(β-hydroxybutyric acid), poly(β-hydroxyvaleric acid), poly(lactic acid-co-glycolic acid), poly(β-hydroxybutyric acid-co-β-hydroxyvaleric acid), poly(β-propiolactone), poly(ε-caprolactone), etc. Examples of polymers having, as repeating units, structural units formed by dehydration condensation of dicarboxylic acids and diols include polyethylene succinate, polybutylene succinate, poly(butylene succinate-co-butylene adipate), etc.

[0028] Of the polyester polyols, poly(ε-caprolactone) (hereinafter sometimes simply referred to as "polycaprolactone") is preferred from the viewpoints of easy availability and excellent granular moldability. Only one type of polyester polyol may be used, or two or more types may be used. When two or more types of polyester polyols are used, two or more types including polycaprolactone are preferred.

[0029] The weight-average molecular weight Mw of the biodegradable polyol is not particularly limited, but from the viewpoint of facilitating the formation of a surface layer, it is preferably 1,000 or more, more preferably 5,000 or more, and even more preferably 10,000 or more. From the viewpoint of not excessively suppressing the elution of functional additives such as acetic acid, the weight-average molecular weight Mw is preferably 100,000 or less. Furthermore, the weight-average molecular weight Mw may be 1,000 to 100,000, 5,000 to 100,000, or 10,000 to 100,000.

[0030] The biodegradable polyol may be a water-soluble polymer or a water-insoluble polymer. In the case of a water-soluble polymer, it dissolves in the presence of water to form pores on the particle surface, allowing the particles to gradually release functional additives such as acetic acid and fertilizers that may be contained therein through the pores. In the case of a water-insoluble polymer, it is difficult to dissolve in the presence of water, preventing leakage of functional additives such as acetic acid and fertilizers that may be contained in the particles, resulting in excellent storage stability. In particular, water-soluble polyether polyols and / or water-insoluble polyester polyols are preferred as the biodegradable polyol. Among the water-insoluble polyester polyols, polycaprolactone is particularly preferred.

[0031] Biodegradable cellulose ester The surface layer may contain a biodegradable cellulose ester. The particles may have a biodegradable cellulose ester on the surface. The biodegradable cellulose ester has a lower environmental impact than non-biodegradable synthetic polymers. Furthermore, when the biodegradable cellulose ester is contained in the surface layer together with a biodegradable polyol, blocking upon contact is more easily suppressed. The biodegradable cellulose ester may contain only one type, or two or more types.

[0032] The biodegradable cellulose ester has acyl groups substituting at least a portion of the hydrogen atoms constituting the hydroxyl groups in cellulose. The number of carbon atoms in the acyl group is preferably 8 or less, more preferably 6 or less, and even more preferably 4 or less. Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group. Among these, from the viewpoint of obtaining high biodegradability, the acetyl group is preferred, and from the viewpoint of high affinity with acetic acid, an acetyl group is more preferred. The biodegradable cellulose ester may have only one type of acyl group, or two or more types. Furthermore, the biodegradable cellulose ester may have a substituent other than the acyl group, as long as the effects of the present disclosure are not impaired. Examples of the substituent include a carboxy group, a carboxymethyl group, a 2-hydroxyethyl group, a 2-hydroxypropyl group, and a methyl group.

[0033] Specific examples of the biodegradable cellulose ester include cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, cellulose acetate butyrate, etc. Among these, cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate are preferred, and cellulose acetate is more preferred from the viewpoint of excellent biodegradability.

[0034] The average degree of substitution (DS) of the biodegradable cellulose ester ａ ) is not particularly limited, and a desired average degree of substitution can be selected depending on the application. From the viewpoint of obtaining good biodegradability, the average degree of substitution is preferably 2.60 or less, more preferably 2.55 or less, and even more preferably 2.50 or less. From the viewpoint of easy granulation, the average degree of substitution is preferably 2.00 or more, more preferably 2.05 or more, and from the viewpoint of obtaining a more uniform shape of the granules, even more preferably 2.10 or more. The average degree of substitution may be 2.00 to 2.60, or may be 2.00 to 2.55, 2.00 to 2.50, 2.05 to 2.60, 2.05 to 2.55, 2.05 to 2.50, 2.10 to 2.60, 2.10 to 2.55, or 2.10 to 2.50.

[0035] In this specification, the average degree of substitution of cellulose ester can be measured by a known or conventional method, for example, １ H-NMR and １３ The cellulose ester can be analyzed and measured by C-NMR. For example, it can be measured by NMR according to the method of Tezuka (Tezuka, Carbonydr. Res. 273, 83 (1995)). Specifically, first, the free hydroxyl groups of the cellulose ester are acylated with a carboxylic acid anhydride in pyridine. The type of carboxylic acid anhydride used here should be selected depending on the purpose of the analysis. For example, butyric anhydride is suitable for analyzing the degree of acetyl substitution of cellulose acetate, and acetic anhydride is suitable for analyzing the degree of butyryl substitution of cellulose butyrate. The obtained sample is dissolved in deuterated chloroform, and １３C-NMR spectrum is measured. For example, when the substituent is an acetyl group, the carbon signals of the acetyl group appear in the region of 169 ppm to 171 ppm in the order of 2-, 3-, and 6-positions from the high magnetic field. As another example, when a cellulose ester having a propionyl group or a cellulose ester not having a propionyl group is treated with propionic anhydride to analyze the degree of propionyl substitution, the signals of the carbonyl carbon of the propionyl group appear in the same order in the region of 172 ppm to 174 ppm. The total substitution degree of the cellulose ester that is treated with carboxylic anhydride by Tezuka's method or the method according to it is 3.0, so the sum of the area of ​​the carbonyl carbon signal of the acyl group that cellulose ester originally has and the carbonyl signal of the acyl group that is introduced by treating with carboxylic anhydride is normalized as 3.0, and then calculate the existence ratio of each acyl group at each corresponding position (in other words, the area ratio of each signal), and this can be the acyl substitution degree of each 2-position, 3-position and 6-position of glucose ring in cellulose ester.It is needless to say that the substituent that contains acyl group that can be analyzed by this method is only the substituent that does not correspond to the carboxylic anhydride that is used for the treatment of analysis.

[0036] The weight-average molecular weight and molecular weight distribution of the biodegradable cellulose ester are not particularly limited, and can be selected as desired depending on the application.For example, from the viewpoint of excellent granular moldability, the weight-average molecular weight Mw of the biodegradable cellulose ester is preferably 100,000 or more, more preferably 120,000 or more.From the viewpoint of higher biodegradability, the weight-average molecular weight Mw is preferably 1,500,000 or less, more preferably 1,200,000 or less, even more preferably 1,000,000 or less, even more preferably 800,000 or less, and particularly preferably 500,000 or less.The molecular weight distribution Mw / Mn calculated from the number-average molecular weight Mn and weight-average molecular weight Mw of the biodegradable cellulose ester affects the biodegradation rate.From the viewpoint of obtaining a desired biodegradation rate, the lower limit of the molecular weight distribution Mw / Mn is preferably 1.3 or more, more preferably 1.5 or more, and even more preferably 2.0 or more.The upper limit is preferably 5.0 or less, more preferably 4.0 or less, and even more preferably 3.0 or less.

[0037] In this specification, the weight-average molecular weight Mw of a polymer compound can be determined by a known or conventional method. Specifically, it is determined by performing size exclusion chromatography (e.g., GPC) measurement using the following apparatus and conditions: Apparatus: GPC apparatus manufactured by Shimadzu Corporation Solvent: Acetone Columns: Two α-M columns (manufactured by Tosoh Corporation), guard column ("TSKgel guard column HXL-H" manufactured by Tosoh Corporation) Flow rate: 0.8 ml / min Temperature: 25°C Sample concentration: 0.25% (wt / vol) Injection volume: 100 μl Detection: RID-20A (differential refractive index detector) Standard substance for calibration curve: PMMA (molecular weight 2,000 to 700,000)

[0038] The biodegradable cellulose ester may be a water-soluble polymer or a water-insoluble polymer, but is preferably a water-insoluble polymer.When it is a water-soluble polymer, it dissolves in the presence of water to form pores on the particle surface, and the functional additives that the particles may contain, such as acetic acid and fertilizer, can be gradually released through the pores.When it is a water-insoluble polymer, it is difficult to dissolve in the presence of water, so it prevents the leakage of the functional additives that the particles may contain, such as acetic acid and fertilizer, and has excellent storage stability.

[0039] The surface layer preferably contains a water-insoluble polymer and a water-soluble polymer. In this case, the water-soluble polymer is dispersed in a matrix of the water-insoluble polymer. When such an agricultural or horticultural composition is applied to soil or the like, the water-soluble polymer is first released from the surface layer upon contact with water in the environment. Release of the water-soluble polymer can form micropores in the surface layer made of the water-insoluble polymer. Functional additives such as acetic acid in the particles are eluted through these pores. Release of the water-soluble polymer also increases the contact area between the remaining surface layer and water. This may accelerate the hydrolysis reaction of the surface layer made of the water-insoluble polymer. From the viewpoint of improving the initial release amount of the functional additive and biodegradability, the surface layer is preferably a mixture of a water-insoluble polymer and a water-soluble polymer. The water-insoluble polymer and the water-soluble polymer may each be used alone or in combination of two or more types.

[0040] The water-insoluble polymer is preferably biodegradable. The water-insoluble polymer may be a biodegradable cellulose ester or a biodegradable polyol, or may be a polymer compound other than a biodegradable polyol or a biodegradable cellulose ester (particularly, a biodegradable polymer compound). The water-insoluble polymer compound is preferably the biodegradable cellulose ester and / or a biodegradable polyol, more preferably polycaprolactone, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, and even more preferably polycaprolactone.

[0041] The water-soluble polymer is preferably biodegradable. The water-soluble polymer is appropriately selected in consideration of its affinity with the water-insoluble polymer. The water-insoluble polymer may be a biodegradable cellulose ester or a biodegradable polyol, or may be one of the other polymer compounds (particularly, biodegradable polymer compounds) described above. Examples of the water-soluble polymer include polyether polyol, carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), and polysaccharides. Among these, the biodegradable polyols are preferred, and polyether polyols are more preferred.

[0042] The total content of the water-insoluble polymer and the water-soluble polymer in the surface layer is preferably more than 50% by mass, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 96% by mass or more, and particularly preferably 98% by mass or more, based on 100% by mass of the total amount of the surface layer. In particular, it is preferable that the total content of the biodegradable polyol and the biodegradable cellulose ester is within the above range.

[0043] The content of the water-soluble polymer in the surface layer is adjusted appropriately depending on the dissolution rate of the functional additive, and is not particularly limited. It is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the total amount of the water-insoluble polymer. The content is preferably less than 100 parts by mass, more preferably less than 90 parts by mass, and even more preferably less than 80 parts by mass. The content may be, for example, 1 part by mass or more but less than 100 parts by mass, 1 part by mass or more but less than 90 parts by mass, 1 part by mass or more but less than 80 parts by mass, 5 parts by mass or more but less than 100 parts by mass, 5 parts by mass or more but less than 90 parts by mass, 5 parts by mass or more but less than 80 parts by mass, 10 parts by mass or more but less than 100 parts by mass, 10 parts by mass or more but less than 90 parts by mass, or 10 parts by mass or more but less than 80 parts by mass.

[0044] The surface layer may contain other components in addition to the biodegradable polyol, the biodegradable cellulose ester, and the other polymer compounds. Examples of the other components include functional additives such as acetic acid, inorganic additives, and the other components that may be contained in the particles described below. The other components may be used alone or in combination of two or more.

[0045] The surface layer may also contain the powder not exposed to the surface (i.e., buried in the surface layer). For example, if the surface layer containing at least a portion of the powder exposed to the surface has a multi-layered structure, the powder in the initial surface layer will end up being present inside the surface layer due to the lamination. Figure 2 shows another embodiment of the agricultural and horticultural composition of the present disclosure. The agricultural and horticultural composition 1 shown in Figure 2 is the same as the agricultural and horticultural composition 1 shown in Figure 1, except that it contains particles 3 buried in a shell layer 5.

[0046] The thickness of the surface layer is not particularly limited and can be appropriately selected so as to obtain a desired functional additive elution rate. From the viewpoint of suppressing the initial elution amount of the functional additive, the thickness of the surface layer is preferably 50 μm or more, more preferably 60 μm or more. Furthermore, from the viewpoint of improving biodegradability, the thickness of the surface layer is preferably 200 μm or less. The thickness of the surface layer is, for example, 50 to 200 μm, and may be 60 to 200 μm.

[0047] (Functional Additive-Containing Layer) The particle preferably comprises a functional additive-containing layer containing a functional additive and a biodegradable polymer having affinity for the functional additive, and the surface layer covering at least a part of the functional additive-containing layer. An example of an embodiment in which the particle has the core-shell structure, the functional additive-containing layer is the core layer, and the surface layer is the shell layer.

[0048] By providing the surface layer as a shell layer on the particles, the initial amount and rate of release of the functional additive from the particles are suppressed. Furthermore, a single application can stably release the functional additive for a long period of time. Furthermore, the material, thickness, coverage, etc. of the surface layer can be selected depending on the type of plant being cultivated, the growing environment, and weather conditions such as rainfall, to obtain a desired release rate of the functional additive. Furthermore, forming the surface layer from a biodegradable material has the effect of reducing the burden on the environment.

[0049] As used herein, a "biodegradable polymer having affinity for functional additives" refers to a biodegradable polymer having a solubility in the functional additive at 50°C of 1% by mass or more and 95% by mass or less. A biodegradable polymer having affinity for a functional additive absorbs a large amount of the functional additive. The affinity of a biodegradable polymer for a functional additive allows an agricultural or horticultural composition to be obtained in which the functional additive is uniformly dispersed. Furthermore, as used herein, solubility is defined as the limit concentration at which a biodegradable polymer dissolves in a certain amount of functional additive, i.e., the concentration (mass%) of a saturated solution.

[0050] The solubility of the biodegradable polymer in the functional additive at 50°C is preferably 2% by mass or more, more preferably 3% by mass or more, from the viewpoint of enabling the functional additive to be contained more uniformly. The solubility is preferably 90% by mass or less, more preferably 85% by mass or less, from the viewpoint of enabling the desired shape to be maintained. The solubility may be, for example, 2 to 90% by mass, 2 to 80% by mass, 3 to 90% by mass, or 3 to 80% by mass.

[0051] The functional additive-containing layer may use any of biodegradable polyols, biodegradable cellulose esters, and other polymer compounds as the biodegradable polymer. The biodegradable polymer is preferably biodegradable cellulose esters or biodegradable polyols, more preferably biodegradable cellulose esters or polyester polyols. The biodegradable polymer may be used alone or in combination of two or more.

[0052] The functional additive-containing layer contains a functional additive. By applying the agricultural and horticultural composition containing the functional additive to the growing environment of a plant, the functional additive is slowly released from the agricultural and horticultural composition. The functional additive may be used alone or in combination with two or more types.

[0053] The functional additives affect plant growth when the agricultural and horticultural composition is applied to the plant's growing environment. Examples of the functional additives include acetic acid, humus, organic acid materials (such as humic acid and fulvic acid), seaweed and seaweed extracts, polysaccharides, amino acids and peptide materials, trace minerals, vitamins, microbial materials (such as Trichoderma, mycorrhizal fungi, yeast, Bacillus subtilis, and rhizobia), microbial metabolites, microbial activators, and functional components derived from plants and animals, as well as various fertilizers, pesticides, repellents, and soil conditioners. For example, the released acetic acid activates stress tolerance genes in plants, improving plant resistance to abiotic stresses such as drought and heat. This allows for the production of high-quality plants with high yields, even in dry or hot environments.

[0054] The content ratio of the functional additive is not particularly limited, and can be suitably selected according to the application.The content ratio of the functional additive is preferably more than 0% by weight with respect to the total amount (100% by weight) of the functional additive-containing layer, and from the viewpoint of relatively increasing the release amount of functional additive at the beginning of use of agricultural and horticultural composition, it is more preferably 0.1% by weight or more, even more preferably 1.0% by weight or more, particularly preferably 5.0% by weight or more.In addition, from the viewpoint of more excellent granular molding property and storage stability, the content ratio of the functional additive is preferably less than 60% by weight, more preferably 55% by weight or less, even more preferably 50% by weight or less. The content may be more than 0% by mass and less than 60% by mass, more than 0% by mass and less than 55% by mass, more than 0% by mass and less than 50% by mass, 0.1% by mass or more and less than 60% by mass, 0.1 to 55% by mass, 0.1 to 50% by mass, 1.0% by mass or more and less than 60% by mass, 1.0 to 55% by mass, 1.0 to 50% by mass, 5.0% by mass or more and less than 60% by mass, 5.0 to 55% by mass, or 5.0 to 50% by mass.

[0055] The functional additive-containing layer preferably contains an inorganic additive. The inorganic additive can control the hydrolysis rate of biodegradable polymers such as biodegradable polyols and biodegradable cellulose esters. In particular, when cellulose acetate is used, the inorganic additive can control the hydrolysis rate of cellulose acetate, thereby improving the storage stability of the agricultural and horticultural composition. Therefore, when the inorganic additive is contained together with, for example, acetic acid, the acetic acid is stably retained in the agricultural and horticultural composition, suppressing a decrease in pH in the soil due to acetic acid release. Therefore, agricultural and horticultural compositions containing inorganic additives exhibit a buffering effect that alleviates adverse effects on plants.

[0056] The inorganic additive is not particularly limited, but from the viewpoints of availability and high safety, alkali metal salts and alkaline earth metal salts are preferred, and alkaline earth metal salts are more preferred. The inorganic additives may be used alone or in combination of two or more.

[0057] Examples of alkali metal salts include potassium salts and sodium salts. Examples of alkaline earth metal salts include magnesium salts and calcium salts. Examples of the salts include carbonates, phosphates, acetates, etc. As the inorganic additives, potassium phosphates or carbonates are preferred from the viewpoint of superior granular moldability and storage stability. Specific examples of the inorganic additives include potassium carbonate, potassium hydrogen carbonate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, and tripotassium phosphate.

[0058] The content of the inorganic additive is adjusted appropriately depending on the content of the functional additive and the type of biodegradable polymer. From the viewpoint of improving granular moldability and storage stability, the content of the inorganic additive is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the total amount of functional additives. From the viewpoint of superior application effect, the content of the inorganic additive is preferably 200 parts by mass or less, more preferably 180 parts by mass or less, and even more preferably 150 parts by mass or less. The content of the inorganic additive may be, for example, 1 to 200 parts by mass, 1 to 180 parts by mass, 1 to 150 parts by mass, 5 to 200 parts by mass, 5 to 180 parts by mass, 5 to 150 parts by mass, 10 to 200 parts by mass, 10 to 180 parts by mass, or 10 to 150 parts by mass.

[0059] In the functional additive-containing layer, the weight-average molecular weight Mw of the polyester polyol corresponding to the biodegradable polyol is not particularly limited, but is preferably 5,000 or more, more preferably 10,000 or more, and even more preferably 30,000 or more, from the viewpoint of excellent granular moldability. The weight-average molecular weight Mw is preferably 3,000,000 or less, more preferably 2,000,000 or less, from the viewpoint of excellent biodegradability. The weight-average molecular weight Mw may be 5,000 to 3,000,000, 5,000 to 2,000,000, 10,000 to 3,000,000, 10,000 to 2,000,000, 30,000 to 3,000,000, or 30,000 to 2,000,000. The molecular weight distribution Mw / Mn, calculated from the number-average molecular weight Mn and weight-average molecular weight Mw of the polyester polyol, affects the biodegradation rate of the polyester polyol. From the viewpoint of obtaining a desired biodegradation rate, the molecular weight distribution Mw / Mn is preferably 1.3 or more, more preferably 1.5 or more, and even more preferably 2.0 or more. The molecular weight distribution Mw / Mn is preferably 5.0 or less, more preferably 4.0 or less, and even more preferably 3.0 or less. The molecular weight distribution Mw / Mn may be 1.3 to 5.0, 1.3 to 4.0, 1.3 to 3.0, 1.5 to 5.0, 1.5 to 4.0, 1.5 to 3.0, 2.0 to 5.0, 2.0 to 4.0, or 2.0 to 3.0.

[0060] In the functional additive-containing layer, the weight-average molecular weight and molecular weight distribution of the biodegradable cellulose ester are not particularly limited, and can be selected as desired depending on the application.For example, from the viewpoint of excellent granular moldability, the weight-average molecular weight Mw of the biodegradable cellulose ester is preferably 100,000 or more, more preferably 120,000 or more.From the viewpoint of higher biodegradability, the weight-average molecular weight Mw is preferably 1,500,000 or less, more preferably 1,200,000 or less, even more preferably 1,000,000 or less, even more preferably 800,000 or less, and particularly preferably 500,000 or less.The molecular weight distribution Mw / Mn calculated from the number-average molecular weight Mn and weight-average molecular weight Mw of the biodegradable cellulose ester affects the biodegradation rate.From the viewpoint of obtaining a desired biodegradation rate, the lower limit of the molecular weight distribution Mw / Mn is preferably 1.3 or more, more preferably 1.5 or more, and even more preferably 2.0 or more.The upper limit is preferably 5.0 or less, more preferably 4.0 or less, and even more preferably 3.0 or less.

[0061] The content of the biodegradable polymer in the functional additive-containing layer is preferably 30% by mass or more, more preferably 35% by mass or more, and even more preferably 40% by mass or more, relative to the total amount (100% by mass) of the functional additive-containing layer, from the viewpoint of easily obtaining the desired particles. The content is preferably 90% by mass or less, from the viewpoint of being able to retain the desired amount of functional additive. The content may be, for example, 30 to 90% by mass, 35 to 90% by mass, or 40 to 90% by mass.

[0062] The functional additive-containing layer may contain water. The inclusion of water promotes hydrolysis of the biodegradable polymer. The water content in the functional additive-containing layer is preferably 1% by mass or more, more preferably 2% by mass or more, relative to 100% by mass of the total amount of the functional additive-containing layer. From the viewpoint of achieving superior storage stability, the water content is preferably 5% by mass or less, more preferably 4% by mass or less. The water content is, for example, 1 to 5% by mass, and may be 1 to 4% by mass, 2 to 5% by mass, or 2 to 4% by mass.

[0063] The functional additive-containing layer may contain components other than the above-mentioned components. Examples of the other components include inorganic fillers, colorants, ultraviolet absorbers, light stabilizers, antioxidants, heat stabilizers, and hydrolysis inhibitors. One or more of the other components may be used.

[0064] The coverage of the surface layer is not particularly limited and can be appropriately selected so as to obtain the desired functional additive elution rate. The coverage is preferably 5.0% by mass or more, more preferably 5.5% by mass or more, from the viewpoint of suppressing the initial elution amount of the functional additive. The coverage is preferably 10.0% by mass or less, from the viewpoint of not excessively suppressing the elution rate of the functional additive. The coverage is, for example, 5.0 to 10.0% by mass, and may be 5.5 to 10.0% by mass. The coverage can be determined from the change in mass before and after forming the surface layer.

[0065] (Particles) The particle size of the particles is not particularly limited and can be adjusted to a desired particle size depending on the application. From the viewpoints of storage stability and handling, the average particle size (median diameter) of the particles is preferably 1 mm or more, more preferably 1.2 mm or more, and even more preferably 1.5 mm or more. The average particle size is preferably 5.0 mm or less, more preferably 4.5 mm or less. The average particle size refers to the median diameter in the particle size distribution measured by laser diffraction / scattering method.

[0066] <Powder> The agricultural and horticultural composition of the present disclosure includes a powder at least partially exposed from the particle surface. The presence of the powder on the surface of the agricultural and horticultural composition suppresses blocking between particles of the granular agricultural and horticultural composition. Only one type of powder may be used, or two or more types may be used.

[0067] The average particle size (median diameter) of the powder is 10 to 350 μm, preferably 20 to 300 μm, and more preferably 50 to 250 μm. When the average particle size is 10 μm or more, the opportunity for contact between the particles is reduced, thereby suppressing blocking of the agricultural and horticultural composition. When the average particle size is 350 μm or less, the number of particles adhering to the particle surface can be increased, thereby suppressing blocking of the agricultural and horticultural composition. The average particle size refers to the median diameter in a particle size distribution measured by a laser diffraction / scattering method.

[0068] The powder has an SP value (δ) at 25°C calculated by the Fedors method. Ａ ) (cal / cm ３ ) １／２ is the SP value (δ Ｂ ) (cal / cm ３ ) １／２ higher than δ Ｂ +26 (cal / cm ３ ) １／２ That is, the SP value (δ Ａ ) satisfies the following formula (1). When the powder satisfies the above SP value, the affinity with the biodegradable polyol forming the surface layer becomes appropriate, the powder does not sink in the surface layer, and is uniformly dispersed, so that the powder is uniformly present on the surface of the surface layer, resulting in excellent blocking properties. Ｂ <δ Ａ ≦δ Ｂ +26 (1)

[0069] The SP value (δ Ａ ) and the SP value (δ Ｂ ) and the difference [δ Ｂ -δ Ａ ] is 26 or less, preferably 24 or less, more preferably 20 or less, and even more preferably 17 or less. Ｂ -δ Ａ ] is greater than 0, preferably 5 or greater, more preferably 8 or greater.

[0070] The SP value (δ Ａ ) is preferably 30 or less, more preferably 25 or less.Ａ When the SP value (δ) of the powder is 30 or less, the affinity with the biodegradable polyol forming the surface layer is suitably high, and the uniform dispersion of the powder in the surface layer is excellent. Ａ ) is preferably 10 or more, more preferably 15 or more. Ａ When the value of ) is 10 or more, the affinity with the biodegradable polyol forming the surface layer is appropriately low, the powder is less likely to sink into the surface layer, and at least a part of the powder is likely to be exposed on the particle surface.

[0071] The powder may be either an organic or inorganic material. The organic material is preferably a biodegradable polymer, such as the biodegradable polymers described above. Among these, in order to further suppress blocking, a water-insoluble polymer is preferred, more preferably a biodegradable cellulose ester, and even more preferably cellulose acetate (cellulose acetate) or cellulose propionate.

[0072] The average degree of substitution (DS) of the biodegradable cellulose ester ａ ) is preferably 2.2 to 2.5, more preferably 2.3 to 2.4. When the average degree of substitution is 2.2 or more, powder tends to adhere to the particle surface. When the average degree of substitution is 2.5 or less, better biodegradability can be obtained.

[0073] The content of the powder in the agricultural and horticultural composition is preferably 0.01 to 20% by mass, more preferably 0.1 to 15% by mass, and even more preferably 1 to 10% by mass, relative to 100% by mass of the total amount of the agricultural and horticultural composition. When the content is 0.01% by mass or more, blocking of the agricultural and horticultural composition is further suppressed. When the content is 20% by mass or less, the initial elution amount of functional additives such as acetic acid is further increased.

[0074] (Agricultural and horticultural composition) In the agricultural and horticultural composition, the proportion of aggregates of two or more granular compositions is preferably less than 50% by mass, more preferably less than 30% by mass, and even more preferably less than 10% by mass. When the proportion is less than 50% by mass, it is determined that blocking of the agricultural and horticultural composition is suppressed.

[0075] The agricultural and horticultural composition has a viscosity of 150 g / cm at 60°C. ２ When a load of 1000 kJ / kg is applied and the load is released to separate the agglomerates from the non-agglomerates, the proportion of agglomerated granular composition is preferably less than 50% by mass, more preferably less than 30% by mass, even more preferably less than 10% by mass, and particularly preferably less than 5% by mass. When the proportion is less than 50% by mass, the agricultural and horticultural composition is judged to have excellent stability.

[0076] When 0.2 g of the agricultural and horticultural composition is added to 200 ml of water at 30°C and immersed for 1 hour, the amount of elution into water is preferably less than 60% by mass, more preferably less than 50% by mass, even more preferably less than 30% by mass, even more preferably less than 20% by mass, and particularly preferably less than 10% by mass. When the above proportion is less than 60% by mass, the agricultural and horticultural composition is deemed to have excellent sustained release properties. For example, when the composition comprises particles having a core-shell structure, the elution amount is calculated as the total elution amount when the granular composition before the formation of the surface layer is immersed for 1 hour at 30°C. Each elution amount can be calculated from the conductivity of the aqueous solution using an electrical conductivity detector.

[0077] The agricultural and horticultural composition of the present disclosure can be used, for example, as an agricultural material for various agricultural or horticultural crops that are sensitive to various functional additives. The agricultural and horticultural composition may be applied to plants or their growing environments together with fertilizers, for example.

[0078] The agricultural and horticultural compositions of the present disclosure can be produced by known or conventional methods. First, the particles are produced by a known or conventional granulation method such as tumbling granulation, fluidized bed granulation, tumbling fluidized bed granulation, or spray-drying granulation, and then the particles are used as particle precursors, and the surface layer is formed on the surfaces of the particle precursors.

[0079] The particle precursor can be obtained, for example, by loading a biodegradable polymer and an inorganic additive into a tumbling granulator, spraying the functional additive or a solution thereof while tumbling at a predetermined temperature, and granulating until the desired particle diameter is achieved.

[0080] The amount of functional additive added during granulation is greater than 0 parts by mass, preferably 1.0 parts by mass or more, more preferably 5.0 parts by mass or more, and even more preferably 10.0 parts by mass or more, relative to 100 parts by mass of the total amount of biodegradable polymer. From the viewpoint of granular moldability, the amount of the functional additive is preferably 150 parts by mass or less, more preferably 120 parts by mass or less. The amount of the functional additive may be, for example, greater than 0 parts by mass and 150 parts by mass or less, greater than 0 parts by mass and 120 parts by mass or less, 1.0 to 150 parts by mass, 1.0 to 120 parts by mass, 5.0 to 150 parts by mass, 5.0 to 120 parts by mass, 10.0 to 150 parts by mass, or 10.0 to 120 parts by mass.

[0081] The amount of inorganic additive added during granulation is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the functional additive. The amount of the inorganic additive is preferably 200 parts by mass or less, more preferably 180 parts by mass or less, and even more preferably 150 parts by mass or less. The amount of the inorganic additive may be, for example, 1 to 200 parts by mass, 1 to 180 parts by mass, 1 to 150 parts by mass, 5 to 200 parts by mass, 5 to 180 parts by mass, 5 to 150 parts by mass, 10 to 200 parts by mass, 10 to 180 parts by mass, or 10 to 150 parts by mass.

[0082] During granulation, a small amount of water may be added as a granulation aid, if necessary, within the range that does not impair the effects of the present disclosure. After granulation, the water content may be adjusted by drying, or the particle size may be adjusted by sieving or the like.

[0083] Particles having the core-shell structure can be produced by forming a surface layer on the surface of the particle precursor. The method for forming the surface layer is not particularly limited, and can be formed by a known or conventional method. For example, particles having a surface layer on their surface can be obtained by spraying or dropping a resin composition (e.g., a solution) containing a material constituting the surface layer (e.g., a biodegradable polyol) onto the particle precursor in a fluidized state and mixing it. Specifically, for example, the particle precursor can be introduced into a jet tower, a jet of the particle precursor is formed by hot air, and the resin composition is sprayed onto this jet, thereby forming a surface layer on the surface of the particle precursor.

[0084] Next, a powder is attached to the surface of the particles. The method for attaching the powder is not particularly limited and can be any known or conventional method. For example, the particles and the powder are mixed and stirred, and then, if necessary, sieved to remove excess powder, followed by drying. In this manner, the agricultural and horticultural composition of the present disclosure can be produced.

[0085] Alternatively, the powder may be attached to particles in which the particle precursor (core layer) is coated with the resin composition. In this case, the powder is attached while the surface layer of the particle has fluidity. In this way, a structure can be formed in which the powder is partially embedded in the surface layer and partially exposed from the surface of the particle.

[0086] The particles to which the powder is attached may then be further coated with a resin composition that forms the surface layer. Furthermore, the resin composition coating and the powder attachment may be repeated. When attempting to produce an agricultural or horticultural composition having a thick surface layer, a large amount of the resin composition that forms the surface layer is applied. In this case, blocking occurs between the surface layer or between the resin compositions during the formation of the surface layer. However, by first preparing a surface layer in which the powder is exposed from the surface and then applying the resin composition, the surface layer can be multilayered, thereby forming a thick surface layer while suppressing blocking during production. Furthermore, when the resin composition coating and the powder attachment are repeated, it is preferable that the repetition end with the powder attachment in order to expose a portion of the powder from the surface of the surface layer. The number of repetitions is not particularly limited and is set appropriately depending on the elution rate of the functional additive and the thickness of the surface layer. In this manner, the agricultural or horticultural composition of the present disclosure can also be produced, including the powder that is not exposed on the surface (i.e., buried in the surface layer).

[0087] Each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. Each configuration and combination thereof in each embodiment is an example, and addition, omission, substitution, and other modifications of configurations are possible as appropriate within the scope of the present disclosure. Furthermore, each invention according to this disclosure is not limited by the embodiments or the following examples, but is limited only by the scope of the claims.

[0088] Hereinafter, one embodiment of the present disclosure will be described in more detail based on examples, but the present disclosure is not limited to these examples.

[0089] Example 1: 50 parts by mass of acetic acid-containing granules (average particle size approximately 2-5 mm) were added to a stainless steel can, and while stirring with a stirrer at a rotation speed of 300 r / min, 30 parts by mass of a polycaprolactone solution (10% by mass acetone solution) was added. Then, 50 parts by mass of cellulose acetate powder (average degree of substitution 2.4) was added. After stirring for a while, the granules and powder were separated using a sieve, and the granules were dried at 40°C. The addition of the polycaprolactone solution and the cellulose acetate powder was repeated three times to prepare a granular composition (powder content of 5-8% by mass). The granular composition was composed of acetic acid-containing granules with a core-shell structure coated with a surface layer made of polycaprolactone, to which the cellulose acetate powder adhered. The SP value of polycaprolactone at 25°C calculated by the Fedors method was 10.2 (cal / cm ３ ) １／２ is.

[0090] Example 2 A granular composition was prepared in the same manner as in Example 1, except that the number of repetitions was changed to five.

[0091] Example 3 A granular composition was prepared in the same manner as in Example 2, except that an acetone solution of 9% by mass of polycaprolactone and 1% by mass of polyethylene glycol was used instead of the polycaprolactone solution (10% by mass acetone solution). The SP value of polyethylene glycol at 25°C calculated by the Fedors method was 9.5 (cal / cm ３ ) １／２The SP value of the polyol forming the surface layer was calculated from the mass ratio to be 10.1 (cal / cm ３ ) １／２ is.

[0092] Example 4 A granular composition was prepared in the same manner as in Example 2, except that the amount of polycaprolactone solution added was changed to 20 parts by mass.

[0093] Comparative Example 1 A granular composition was prepared in the same manner as in Example 1, except that no cellulose acetate powder was added.

[0094] Comparative Example 2 A granular composition was prepared in the same manner as in Example 1, except that sand was used instead of the cellulose acetate powder.

[0095] Comparative Example 3 A granular composition was prepared in the same manner as in Example 1, except that polycaprolactone powder was used instead of the cellulose acetate powder.

[0096] Comparative Example 4 A granular composition was prepared in the same manner as in Example 2, except that starch powder was used instead of the cellulose acetate powder.

[0097] <Evaluation> The granular compositions of the Examples and Comparative Examples were evaluated as follows, and the results are shown in the table.

[0098] (1) Evaluation of Aggregation (Blocking) The proportion of two or more aggregated granular compositions among the obtained granular compositions was calculated, and the aggregation was evaluated according to the following criteria: ◯: Amount of aggregation less than 10% by mass Δ: Amount of aggregation 10% by mass or more but less than 50% by mass ×: Amount of aggregation 50% by mass or more

[0099] (2) Stability test The obtained granular composition was subjected to a test at 150 g / cm at 60°C. ２ A load of 1000 kJ / kg was applied, and the load was released to separate the agglomerates from the non-agglomerates, and the mass proportion of the agglomerated granular composition was calculated as a percentage.

[0100] (3) Sustained Release Test 200 ml of water was placed in a screw tube, and the screw tube was immersed in a water bath at 30°C for 1 hour. 0.2 g of the resulting granular composition was then immersed in the water in the screw tube. The mass ratio of the amount dissolved into water after immersion for 1 hour was calculated as a percentage of the total amount dissolved. The total amount dissolved was the amount dissolved when the granular composition (i.e., the acetic acid-containing granules) before the surface layer was formed was immersed for 1 hour at 30°C. Each amount dissolved was monitored using an electrical conductivity detector based on the conductivity of the aqueous solution.

[0101]

[0102] As shown in Table 1, the granular compositions of the examples were evaluated as having a small amount of aggregation and being less prone to blocking. Furthermore, they were evaluated as having excellent stability and sustained release properties, with no aggregation even under pressure at 60°C. On the other hand, when no powder was used (Comparative Example 1), when the average particle size of the powder was large (Comparative Example 2), or when a powder with an SP value that was not within a specific range was used as the powder (Comparative Examples 3 and 4), the compositions were evaluated as having poor aggregation properties and prone to blocking. Furthermore, depending on the substance to be attached, the compositions were also evaluated as having poor stability and sustained release properties.

[0103] Variations of the present invention are described below. [Appendix 1] A biodegradable polyol-containing particle having a particle surface and a powder at least partially exposed from the particle surface, wherein the powder has an average particle diameter of 10 to 350 μm and an SP value (δ) at 25° C. calculated by the Fedors method. Ａ ) (cal / cm ３ ) １／２ is the SP value (δ Ｂ ) (cal / cm ３ ) １／２ higher than δ Ｂ +26 (cal / cm ３ ) １／２[Appendix 2] The granular agricultural and horticultural composition according to Appendix 1, wherein the biodegradable polyol is a water-soluble polyether polyol and / or a water-insoluble polyester polyol. [Appendix 3] The granular agricultural and horticultural composition according to Appendix 2, wherein the water-insoluble polyester polyol is poly(ε-caprolactone). [Appendix 4] The granular agricultural and horticultural composition according to any one of Appendixes 1 to 3, wherein the biodegradable polyol has a weight-average molecular weight Mw of 1,000 to 100,000. [Appendix 5] The granular agricultural and horticultural composition according to any one of Appendixes 1 to 4, wherein the particles further have a biodegradable cellulose ester on the surface thereof. [Appendix 6] The granular agricultural and horticultural composition according to Appendix 5, wherein the biodegradable cellulose ester is one or more selected from the group consisting of cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate. [Appendix 7] The average degree of substitution (DS) of the biodegradable cellulose ester is ａThe granular agricultural and horticultural composition according to any one of Appendices 5 to 6, wherein the weight-average molecular weight Mw of the biodegradable cellulose ester is 100,000 or more. [Appendix 9] The granular agricultural and horticultural composition according to any one of Appendices 5 to 8, wherein the weight-average molecular weight Mw of the biodegradable cellulose ester is 1,500,000 or less. [Appendix 10] The granular agricultural and horticultural composition according to any one of Appendices 5 to 9, wherein the molecular weight distribution Mw / Mn of the biodegradable cellulose ester is 1.3 or more. [Appendix 11] The granular agricultural and horticultural composition according to any one of Appendices 5 to 10, wherein the molecular weight distribution Mw / Mn of the biodegradable cellulose ester is 5.0 or less. [Appendix 12] The granular agricultural and horticultural composition according to any one of Appendices 1 to 11, wherein the particles have a surface layer, and the surface layer contains a water-insoluble polymer and a water-soluble polymer. [Appendix 13] The granular agricultural and horticultural composition according to Appendices 12, wherein the total content of the water-insoluble polymer and the water-soluble polymer is more than 50% by mass, relative to 100% by mass of the total amount of the surface layer. [Appendix 14] The granular agricultural and horticultural composition according to Appendices 12 or 13, wherein the content of the water-soluble polymer in the surface layer is 1 part by mass or more, relative to 100 parts by mass of the total amount of the water-insoluble polymer. [Appendix 15] The granular agricultural and horticultural composition according to any one of Appendices 12 to 14, wherein the content of the water-soluble polymer in the surface layer is less than 100 parts by mass, relative to 100 parts by mass of the total amount of the water-insoluble polymer. [Appendix 16] The granular agricultural and horticultural composition according to any one of Appendices 12 to 15, wherein the thickness of the surface layer is 50 to 200 μm. [Appendix 17] The granular agricultural and horticultural composition according to any one of Appendices 12 to 16, wherein the particles comprise a functional additive-containing layer containing a functional additive and a biodegradable polymer having affinity for the functional additive, and the surface layer covering at least a portion of the functional additive-containing layer. [Appendix 18] The granular agricultural and horticultural composition according to Appendices 17, wherein the solubility of the biodegradable polymer in the functional additive at 50°C is 2% by mass or more. [Appendix 19] The granular agricultural and horticultural composition according to Appendices 17 or 18, wherein the solubility of the biodegradable polymer in the functional additive at 50°C is 90% by mass or less.[Appendix 20] The granular agricultural and horticultural composition according to any one of Appendices 17 to 19, wherein the functional additive is acetic acid. [Appendix 21] The granular agricultural and horticultural composition according to any one of Appendices 17 to 20, wherein the content of the functional additive is more than 0% by mass and less than 60% by mass, relative to the total amount (100% by mass) of the functional additive-containing layer. [Appendix 22] The granular agricultural and horticultural composition according to any one of Appendices 17 to 21, wherein the functional additive-containing layer further contains an inorganic additive. [Appendix 23] The granular agricultural and horticultural composition according to any one of Appendices 17 to 22, wherein the inorganic additive is an alkaline earth metal salt. [Appendix 24] The granular agricultural and horticultural composition according to any one of Appendices 17 to 23, wherein the content of the inorganic additive is 1 to 200 parts by mass, relative to 100 parts by mass of the total amount of the functional additives. [Appendix 25] The granular agricultural and horticultural composition according to any one of Appendices 12 to 24, wherein the coverage of the surface layer is 5.0 to 10.0% by mass. [Appendix 26] The granular agricultural and horticultural composition according to any one of Appendices 1 to 25, wherein the average particle size of the particles is 1 mm or more. [Appendix 27] The granular agricultural and horticultural composition according to any one of Appendices 1 to 26, wherein the average particle size of the particles is 5.0 mm or less. [Appendix 28] The SP value (δ) of the powder. ＡThe granular agricultural and horticultural composition according to any one of Appendices 1 to 27, wherein the ratio of the powder is 0.01 to 10% by mass based on the total amount of the granular agricultural and horticultural composition. [Appendix 29] The granular agricultural and horticultural composition according to any one of Appendices 1 to 28, wherein the ratio of the powder is 0.01 to 10% by mass based on the total amount of the granular agricultural and horticultural composition. [Appendix 30] The granular agricultural and horticultural composition according to any one of Appendices 1 to 29, wherein the powder is a biodegradable cellulose ester. [Appendix 31] The granular agricultural and horticultural composition according to Appendices 30, wherein the biodegradable cellulose ester as the powder comprises cellulose acetate having an average degree of substitution of 2.2 to 2.5. [Appendix 32] The granular agricultural and horticultural composition according to any one of Appendices 1 to 31, wherein the ratio of two or more granular compositions agglomerated is less than 50% by mass. [Appendix 33] The granular agricultural and horticultural composition according to any one of Appendices 1 to 32, wherein the particles have a core-shell structure comprising a core layer and a shell layer covering the core layer, and the shell layer provides the surface of the particles. [Appendix 34] A method for producing a granular agricultural and horticultural composition having a core-shell structure comprising a shell layer containing a biodegradable polyol, the method comprising: adding a resin composition having a core layer coated with a resin composition containing a biodegradable polyol to a granular agricultural and horticultural composition having an average particle diameter of 10 to 350 μm and an SP value (δ) at 25° C. calculated by the Fedors method. Ａ ) (cal / cm ３ ) １／２ is the SP value (δ Ｂ ) (cal / cm ３ ) １／２ higher than δ Ｂ +26 (cal / cm ３ ) １／２ A method for producing a granular agricultural and horticultural composition, comprising: adhering a powder that is:

[0104] 1 Agricultural and horticultural composition 2 Particle 3 Powder 4 Core layer 5 Shell layer

Claims

1. A particle having a biodegradable polyol on its surface and a powder at least partially exposed from the particle surface, wherein the powder has an average particle diameter of 10 to 350 μm and an SP value (δ) at 25° C. calculated by the Fedors method. Ａ ) (cal / cm ３ ) １／２ is the SP value (δ Ｂ ) (cal / cm ３ ) １／２ Higher than δ Ｂ +26 (cal / cm ３ ) １／２ A granular agricultural and horticultural composition comprising:

2. The granular agricultural and horticultural composition according to claim 1, wherein the biodegradable polyol is a water-soluble polyether polyol and / or a water-insoluble polyester polyol.

3. A granular agricultural and horticultural composition according to claim 1 or 2, wherein said particles further comprise a biodegradable cellulose ester on said surface.

4. The granular agricultural and horticultural composition according to claim 3, wherein the biodegradable cellulose ester is one or more selected from the group consisting of cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate.

5. The granular agricultural and horticultural composition according to claim 2, wherein said water insoluble polyester polyol is poly(ε-caprolactone).

6. A granular agricultural and horticultural composition according to claim 1 or 2, wherein the proportion of said powder is 0.01 to 10 mass % based on the total amount of said granular agricultural and horticultural composition.

7. A granular agricultural and horticultural composition according to claim 6, wherein said powder is a biodegradable cellulose ester.

8. The granular agricultural and horticultural composition of claim 7, wherein the biodegradable cellulose ester as the powder comprises a cellulose acetate having an average degree of substitution of 2.2 to 2.

5.

9. A granular agricultural and horticultural composition as claimed in claim 1 or 2, wherein the particle has a core-shell structure comprising a core layer and a shell layer covering the core layer, the shell layer providing a surface of the particle.

10. A method for producing a granular agricultural and horticultural composition having a core-shell structure with a shell layer containing a biodegradable polyol, the method comprising the steps of: adding a resin composition having a core layer coated with a resin composition containing a biodegradable polyol to a granular agricultural and horticultural composition having an average particle size of 10 to 350 μm and an SP value (δ) at 25°C calculated by the Fedors method. Ａ ) (cal / cm ３ ) １／２ is the SP value (δ Ｂ ) (cal / cm ３ ) １／２ Higher than δ Ｂ +26 (cal / cm ３ ) １／２ 1. A method for producing a granular agricultural and horticultural composition, comprising: adhering a powder of the following formula: and coating the particles to which the powder has been adhered with a resin composition comprising a biodegradable polyol.

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