Layer-forming material, coating structure, method for manufacturing a coating structure, and layer-forming material set

Abstract

This material provides a layer-forming material with excellent blocking suppression properties. [Solution] The layer-forming material of the present invention comprises an environmentally degradable resin A having a main chain but no side chains, one or more selected from the group consisting of ion-crosslinkable polymers, ion-crosslinking agents, and inorganic fillers, and one or more hydrophobic substances selected from the group consisting of waxes, oils and fats, and fatty acids.

Description

Technical Field

[0001] The present invention relates to a layer-forming material, a coated structure, a method for manufacturing the coated structure, and a layer-forming material set.

Background Art

[0002] Various developments have been made on layer-forming materials so far. As this type of technology, for example, the technology described in Patent Document 1 is known. Patent Document 1 describes a coated granular fertilizer having a structure in which a protective layer containing a polyolefin obtained by blending different resins of a biodegradable polyester and a polyolefin (thermoplastic resin) and containing one or more substances that promote the oxidative decomposition reaction of the polymer is coated.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As a result of the study by the present inventors, it has been found that when an environmentally degradable resin having no side chain is used as a coating material, blocking occurs in which the coated objects fuse together. ​​​​​​​​​​​​ 1. An environmentally degradable resin containing an environmentally degradable resin A having a main chain but no side chains, One or more selected from the group consisting of ion-crosslinkable polymers, ion-crosslinking agents, and inorganic fillers, A layer-forming material comprising one or more hydrophobic substances selected from the group consisting of waxes, oils and fats, and fatty acids. 2. The layer-forming material described in 1., A layer-forming material wherein the hydrophobic substance comprises one or more hydrophobic substances X that satisfy at least one of the following (a) to (d). (a) The molecular weight is between 15 and 20,000. (b) The crystallization time, as measured by the crystallization test described below, is between 1 second and 300 seconds. (Crystallization test) Bottom area: 15.9cm 2 A 1.4 cm high aluminum container is placed in 4 g of the hydrophobic substance X and melted on a 90°C hot plate. The container is then moved off the hot plate and left to stand at room temperature (25°C). The time (in seconds) from immediately after the container is settling until the molten material loses its fluidity is measured and defined as the crystallization time. (c) The material has one of the following characteristics, as measured according to the bending test described below: a bending modulus of 1000 MPa or less, a bending strength of 7 MPa or less, or a bending strain of 0.1% or more. (Bending test) A test specimen measuring 1 cm wide x 3 cm long x 0.2 cm thick is prepared by placing 1 g of the hydrophobic substance X into a silicone mold, placing the mold on a 100°C hot plate, and then allowing it to cool to room temperature after melting. Using the obtained test specimens, a bending test was performed at room temperature (25°C), with a support distance of 2.4 cm, and a pressing speed of 1 mm / min. The bending modulus (MPa), bending strength (MPa), and bending strain (%) were then measured. (d) The HSP value for the environmentally degradable resin A is 6.0 or higher. 3. A layer-forming material as described in 1. or 2., The hydrophobic substance comprises one or more selected from the group consisting of hydrocarbon waxes, fatty acid waxes, higher alcohol waxes, glycerin fatty acid esters, and fatty acids, and is a layer-forming material. 4. A layer-forming material described in any one of 1. to 3., A layer-forming material wherein the hydrophobic substance comprises a hydrophobic substance X' having an HSP value of less than 6.0 relative to the environmentally degradable resin A. 5. A layer-forming material described in any one of 1. to 4., A layer-forming material wherein at least one of the hydrophobic substances has a melting point of 110°C or lower. 6. A layer-forming material described in any one of 1. to 5., A layer-forming material comprising one or more selected from the group consisting of an antifoaming agent, a plasticizer, and a surface modifier for the inorganic filler. 7. A layer-forming material described in any one of 1. to 6., A layer-forming material wherein the inorganic filler comprises one or more selected from the group consisting of silica, talc, magnesium oxide, calcium oxide, alumina, titanium oxide, calcium carbonate, clay, potassium titanate, mica, glass flakes, whiskers, ferrite, iron oxide, zeolite, and magnesium sulfate. 8. A layer-forming material described in any one of 1. to 7., The ion-crosslinkable polymer comprises at least one of the following components (A) and (B): If the ion-crosslinkable polymer contains the following component (A), the ion-crosslinking agent contains one or more selected from the group consisting of the following components (B), (C), and (D): If the ion-crosslinkable polymer contains the following component (B), the ion-crosslinking agent is a layer-forming material comprising one or more selected from the group consisting of the following components (A), (C), and (D). (A) Polyanions having monovalent or divalent or more anionic groups, or salts containing such polyanions (B) Polycations having monovalent or divalent or more cationic groups, or salts containing such polycations (C) Inorganic cations having monovalent or divalent or more cations, or salts containing one or more of such inorganic cations. (D) An anionic monomer having a monovalent or divalent or more anionic group, or an acid containing said anionic monomer 9. A layer-forming material described in any one of 1. to 8., A layer-forming material used to form a coating layer on the surface of an object to be coated. 10.9. A layer-forming material as described above, The aforementioned coating target is a layer-forming material containing agricultural active ingredients. 11. The object to be covered, A coating layer that covers at least a portion of the surface of the object to be coated, A coating structure wherein the coating layer includes a layer-forming material according to any one of 1. to 9. 12. A method for manufacturing a coated structure, comprising the step of forming a coating layer on the surface of an object to be coated using a layer-forming material described in any one of 1 to 9. 13. A layer-forming material set comprising a first molding material and a second molding material, The first molding material includes an environmentally degradable resin, and the environmentally degradable resin includes an environmentally degradable resin A having a main chain but no side chains. The second molding material contains a hydrophobic substance, A layer-forming material set comprising one or more selected from the group consisting of ion-crosslinkable polymers, ion-crosslinking agents, and inorganic fillers, which are included in either or both of the first molding material and the second molding material. 14. A set of layer-forming materials as described in 13. A layer-forming material set in which the first molding material is in the form of a powder, granules, pellets, or briquettes. 15. A set of layer-forming materials as described in 13. or 14., A layer-forming material set wherein the second molding material comprises one or more selected from the group consisting of an antifoaming agent, a plasticizer, and a surface modifier for the inorganic filler.

Advantages of the Invention

[0008] According to the present invention, there are provided a layer-forming material excellent in blocking suppression, a coating structure, a method for manufacturing the coating structure, and a layer-forming material set.

Mode for Carrying Out the Invention

[0009] The outline of the layer-forming material of the present embodiment will be described.

[0010] The layer-forming material of the present embodiment includes an environmentally degradable resin containing an environmentally degradable resin A having a main chain and no side chain, one or two or more selected from the group consisting of an ion-crosslinkable polymer, an ion crosslinking agent, and an inorganic filler, and one or two or more hydrophobic substances selected from the group consisting of wax, fats and oils, and fatty acids.

[0011] In the present specification, the hydrophobic substance may be any one of only wax, only fats and oils, only fatty acids, or a mixture of wax and fats and oils, a mixture of fats and oils and fatty acids, a mixture of wax and fatty acids, or a mixture of wax, fats and oils and fatty acids. The same applies to "hydrophobic substance X" and the like described later.

[0012] According to the findings of the present inventors, by using the environmentally degradable resin A having no side chain and the hydrophobic substance in combination, when a layer-forming material containing both is used as a coating material, it has been found that the occurrence of blocking in which the coated objects fuse to each other can be suppressed. Although the detailed mechanism is not clear, one of the factors causing blocking is that since the environmentally degradable resins A do not have side chains, the intermolecular distance becomes close, and the interaction between esters is likely to occur. On the other hand, it is presumed that by adding a hydrophobic substance, the intermolecular interaction in the environmentally degradable resin A is relaxed, and the above-mentioned blocking is suppressed.

[0013] The layer-forming material of this embodiment is used to form a layered structure, and is preferably used as a coating material or a film material, for example.

[0014] The layer-forming material can be used as a coating material to form a coating layer on the surface of the object to be coated. An example of a coating layer may be used to form a resin shell structure that encloses one or more objects to be coated. Furthermore, the coating layer can be used to form resin particles having a hollow structure including an inner layer and an outer layer.

[0015] The coating is preferably applied to a material containing agricultural active ingredients, but is not limited to this, and may also contain other water-soluble ingredients. Examples of other water-soluble ingredients include efficacy ingredients used in pharmaceuticals, cosmetics, foods, etc. Agricultural activating ingredients can be any substance used to promote, accelerate, or protect crops, such as fertilizer components and pesticide components. Furthermore, the coating may include fragrances and pigments. Examples of fragrances include synthetic fragrances, natural essential oils, natural fragrances, and animal and plant extracts. Examples of pigments include those used in paints or inks. Furthermore, examples of materials to be covered include air or other gases that have thermal insulation properties. These may be included individually, or any combination of two or more may be included.

[0016] The coating layer can, for example, gradually release the coated material, such as the water-soluble components mentioned above, to the outside. Furthermore, depending on the requirements of the coated material, the coating layer can adjust the permeability of water, air, and / or carbon dioxide into the interior.

[0017] The components of the layer-forming material in this embodiment will be described in detail below.

[0018] (Hydrophobic substances) The hydrophobic substance is a mixture of two or more waxes, oils and fats, and fatty acids, or from the group consisting of these. For example, it may include one or more selected from the group consisting of hydrocarbon waxes, fatty acid waxes, higher alcohol waxes, glycerin fatty acid esters, and fatty acids. Here, the wax may be one of hydrocarbon waxes, fatty acid waxes, or higher alcohol waxes, or a mixture thereof. Fatty acid waxes may include, for example, one or more selected from the group consisting of aliphatic esters, aliphatic ketones, aliphatic amides, and fatty acid metal soaps. Furthermore, any of the following types of wax may be used: natural wax, synthetic wax, or modified wax. Examples of natural waxes include those derived from plants, animals, minerals, and petroleum. Examples of fats and oils include glycerin fatty acid esters. Glycerin fatty acid esters may include monoglycerin fatty acid esters, diglycerin fatty acid esters, triglycerin fatty acid esters, or mixtures of two or more of these. In addition, glycerin fatty acid esters may include polyglycerin fatty acid esters, such as those in which one hydroxyl group of glycerin is dimerized by an ether bond. Fatty acids include fatty acids with fewer than 10 carbon atoms and higher fatty acids with 10 or more carbon atoms. Fatty acids may also include straight-chain fatty acids that have a main chain but no side chains, branched fatty acids that have both a main chain and side chains, and / or cyclic fatty acids that contain at least one cyclic structure. Furthermore, fatty acids may also include fatty acid derivatives such as hydroxy fatty acids containing at least one hydroxyl group, and polymers of hydroxy fatty acids. These may be used individually or in combination of two or more. The above fatty acids and aliphatic skeletons each contain saturated and / or unsaturated bonds. The above glycerol fatty acid esters may also include highly purified products obtained by distillation or other means.

[0019] The hydrophobic substance may include one or more of the following waxes and vegetable oils. Specific examples of waxes include natural waxes such as carnauba wax, beeswax, and rice wax; petroleum waxes such as paraffin wax and microcrystalline wax; and synthetic waxes such as Fischer-Tropsch wax and polyethylene wax. Specific examples of vegetable oils include palm oil, soybean oil, rapeseed oil, sunflower oil, palm kernel oil, cottonseed oil, peanut oil, olive oil, coconut oil, corn oil, sesame oil, linseed oil, safflower oil, rice bran oil, and perilla oil.

[0020] The hydrophobic substance content in the layer-forming material is, for example, 1 to 60% by mass, preferably 2 to 45% by mass, and more preferably 3 to 30% by mass, based on 100% by mass of the layer-forming material. Furthermore, the hydrophobic substance content is, for example, 1 to 130 parts by mass, preferably 5 to 120 parts by mass, and more preferably 10 to 110 parts by mass, per 100 parts by mass of the environmentally degradable resin.

[0021] When the hydrophobic substance contains paraffin wax, the paraffin wax content in the layer-forming material is, for example, 1 to 60% by mass, preferably 2 to 45% by mass, and more preferably 3 to 30% by mass, of 100% by mass of the layer-forming material. Furthermore, if the hydrophobic substance contains paraffin wax, the paraffin wax content is, for example, 1 to 125 parts by mass, preferably 5 to 110 parts by mass, and more preferably 10 to 10 parts by mass, per 100 parts by mass of the environmentally degradable resin. In this embodiment, when an environmentally degradable resin A without side chains and a hydrocarbon wax such as paraffin wax are included, the hydrophobic substance may include hydrophobic substances other than paraffin wax, or hydrophobic substances other than hydrocarbon waxes. This further reduces fusion such as blocking.

[0022] The hydrophobic substance preferably contains one or more hydrophobic substances X that satisfy at least one of the following conditions (a) to (d). Here, if the hydrophobic substance includes one type of hydrophobic substance X, this hydrophobic substance X may satisfy at least one, preferably two or more, and more preferably three or more of (a) to (d). If the hydrophobic substance contains two or more hydrophobic substances X, each of the two or more hydrophobic substances X may satisfy at least one, preferably two or more, and more preferably three or more of (a) to (d). Furthermore, each of the two or more hydrophobic substances X may satisfy at least one of (a) to (d) in common.

[0023] (a) The molecular weight of the hydrophobic substance X is, for example, 15 to 20,000, preferably 25 to 19,000, and more preferably 35 to 18,000. Setting it below the upper limit allows the material to have appropriate flexibility. Setting it above the lower limit makes the coating formed by the material less likely to break. The above molecular weight can be calculated by methods such as the viscosity method or the GPC method.

[0024] (b) The crystallization time in the hydrophobic substance X is, for example, 1 second or more and 300 seconds or less, preferably 10 seconds or more and 270 seconds or less, and more preferably 20 seconds or more and 240 seconds or less. Setting it below the upper limit allows the material to be given appropriate flexibility. Setting it above the lower limit allows the material to be given plasticity when returned to room temperature. The crystallization time mentioned above can be measured by the crystallization test described below. (Crystallization test) Bottom area: 15.9cm 2 A 1.4 cm high aluminum container is placed in a container containing 4 g of hydrophobic substance X, which is then melted on a 90°C hot plate. After removing the container from the hot plate and allowing it to stand at room temperature (25°C), the time (in seconds) from the moment of standing until the molten material loses its fluidity is measured and defined as the crystallization time.

[0025] (c) The hydrophobic material X has one of the following properties: a flexural modulus of 1000 MPa or less, a flexural strength of 7 MPa or less, or a flexural strain of 0.1% or more. The above-mentioned flexural modulus is, for example, 1 MPa to 1000 MPa, preferably 10 MPa to 950 MPa, and more preferably 20 MPa to 900 MPa. Setting it below the upper limit allows the material to be given appropriate flexibility. Setting it above the lower limit makes the coating formed by the material less likely to break. The bending strength described above is, for example, 0.1 MPa to 7 MPa, preferably 0.5 MPa to 6.5 MPa, and more preferably 1 MPa to 6 MPa. Setting it below the upper limit allows the material to have appropriate flexibility. Setting it above the lower limit makes the coating formed by the material less likely to break. The bending strain described above is, for example, 0.1% to 260%, preferably 0.15% to 250%, and more preferably 0.2% to 240%. Setting it above the lower limit imparts appropriate flexibility to the material. Setting it below the upper limit imparts appropriate sustained release properties. The above-mentioned flexural modulus, flexural strength, and flexural strain can be measured according to the following bending test. (Bending test) A test specimen measuring 1 cm wide x 3 cm long x 0.2 cm thick is prepared by placing 1 g of hydrophobic substance X into a silicone mold, placing the mold on a 100°C hot plate, and then allowing it to melt and cool to room temperature. Using the obtained test specimens, a bending test was performed at room temperature (25°C), with a support distance of 2.4 cm, and a pressing speed of 1 mm / min. The bending modulus (MPa), bending strength (MPa), and bending strain (%) were then measured.

[0026] (d) The lower limit of the HSP value of the hydrophobic substance X for at least one of the environmentally degradable resins A is, for example, 6 or more, preferably 6.5 or more, and more preferably 7 or more. Setting it above the lower limit allows for appropriate phase separation in the material and control of sustained release. On the other hand, the upper limit of the HSP value of the hydrophobic substance X is not particularly limited, but may be 15 or less, 14 or less, or 13 or less.

[0027] Hansen's solubility parameter (HSP) is an index that represents the solubility of one substance, indicating how much of it dissolves in another substance. HSP represents solubility as a three-dimensional vector. A vector typically has a variance term (δ d ), polarity term (δ p ), hydrogen bond term (δ h It can be represented as follows. And if the vectors are similar, it can be judged that they have high solubility. The similarity of the vectors can be judged by the distance of the Hansen solubility parameter (HSP value).

[0028] Here, the computer software HSPiP, developed by Hansen and Abbott, includes a function to calculate HSP distance and a database listing Hansen parameters for various resins and solvents or non-solvents. The Hansen solubility parameters (HSP values) used herein can be calculated using the HSPiP (Hansen Solubility Parameters in Practice) software. Version 6.0.04 may be used. Alternatively, for example, values ​​listed in the Solvent list and Polymer list included in HSPiP 3rd version, corrected for 25°C, may be referred to. For resins and solvents or non-solvents not listed in the Solvent list, the values ​​can be calculated using an estimation method called Y-MB, which employs a neural network. By inputting the molecular structure into the Y-MB calculation software included with HSPiP, it is automatically decomposed into atomic groups, and the HSP value and molecular volume are calculated.

[0029] Furthermore, the hydrophobic substance may include a hydrophobic substance X that is solid at 25°C and / or a hydrophobic substance X that is liquid at 25°C.

[0030] The upper limit of the melting point of at least one (solid) hydrophobic substance X contained in the hydrophobic material may be, for example, 110°C or lower. This allows the processing temperature of the material to be lowered. On the other hand, the lower limit of the melting point of at least one (solid) of the solid hydrophobic substance X may be, for example, 20°C or higher.

[0031] The hydrophobic substance may further include, in addition to the hydrophobic substance X described above, a hydrophobic substance X' that does not satisfy at least condition (d), or a hydrophobic substance X'' that does not satisfy at least condition (c). In this case, the upper limit of the HSP value of the hydrophobic substance X' for at least one of the environmentally degradable resins A may be less than 6, for example. This improves the compatibility of the hydrophobic substance and enhances the strength of the film formed from the material.

[0032] (Environmentally degradable resin) Environmentally biodegradable resins can be used if they are decomposed by microorganisms in nature, such as bacteria, and partially or entirely consist of water and carbon dioxide, thus circulating back into nature. Materials that conform to the biodegradability test in accordance with ISO 14855-2 (JIS K 6953-2) are preferred. Furthermore, known environmentally degradable resins can be used.

[0033] The environmentally degradable resin includes environmentally degradable resin A, which has a main chain but no side chains. The environmentally degradable resin A may include one or more specific examples of environmentally degradable resins described below. Furthermore, the environmentally degradable resin may include environmentally degradable resin B having a main chain and side chains, in addition to environmentally degradable resin A. In this specification, the main chain includes a structure in which one or more repeating units contained within the molecule of the biodegradable resin are bonded. Hydroxyl groups, carboxyl groups, amino groups, etc., may be bonded to each of the ends of the main chain. On the other hand, the side chain includes structures that branch off from parts of the main chain other than both ends. The side chain has one or more predetermined functional groups on at least one of the repeating units in the main chain. The functional groups are bonded to the carbon skeleton (carbon chain) that constitutes the side chain, but in the case of a functional group containing carbon atoms, the carbon atoms in the functional group may constitute at least part or all of the carbon skeleton. Specific examples of functional groups include hydrophobic groups and hydrophilic groups, but it is preferable that at least hydrophobic groups are included. Hydrophobic groups may include, for example, aliphatic hydrocarbon groups and aromatic hydrocarbon groups. Hydrophilic groups may include carboxylic acid groups, sulfonic acid groups, hydroxyl groups, and amino groups (however, groups consisting of "=O" directly bonded to the carbon atoms of the main chain do not need to be included in the above-mentioned hydrophilic groups). As an example of environmentally degradable resin A, an environmentally degradable resin having a main chain containing an ester structure and no side chains may be included, for example, selected from aliphatic polyester resins other than polylactic acid or aromatic aliphatic polyester resins. On the other hand, as an example of environmentally degradable resin B, an environmentally degradable resin having a main chain containing an ester structure and side chains may be included, for example, selected from polylactic acid, PHA resins, P3HB resins, etc. Furthermore, the environmentally degradable resin may include other environmentally degradable resins other than environmentally degradable resin A and environmentally degradable resin B, as long as it does not impair the effects of the invention.

[0034] Specific examples of environmentally degradable resins include biodegradable plastics, such as polyester resins including aliphatic polyester resins, aromatic aliphatic polyester resins, and polyhydroxyalkanol (PHA) resins, as well as non-polyester resins such as natural polymers. These may be used individually or in combination of two or more. Furthermore, aliphatic polyester resins, aromatic aliphatic polyester resins, and PHA resins may each have raw materials that are partially or entirely derived from biomass, or the raw materials may be derived from petroleum. Environmentally degradable resins may contain either biomass-derived resins or natural polymers alone, or they may contain two or more of these, for example, a biomass-derived resin and a petroleum-derived resin. Aliphatic polyester resins may include, for example, one or more of the following: polylactic acid (PLA), polybutylene succinate (PBS), polyhydroxybutyrate, polycaprolactone (PCL), polybutylene succinate / adipate (PBSA), polyethylene succinate, polymalic acid, polyglycolic acid (PGA), polydioxanone, and poly(2-oxetanone). Aliphatic polyester resins may contain these alone or copolymers containing two or more of these. Aromatic aliphatic polyester resins are polyester resins having both aromatic and aliphatic moieties, and may include one or more of the following: polybutylene succinate / terephthalate (PBST), polybutylene adipate / terephthalate (PBAT), polytetramethylene adipate / terephthalate, polyethylene adipate terephthalate (PEAT), etc. PHA-based resins may include, for example, P3HB-based resins containing polyhydroxyalkanoates and / or 3-hydroxybutyrate units. P3HB-based resins may be polymers containing only 3-hydroxybutyrate units, or copolymers containing repeating units other than 3-hydroxybutyrate units. Specific examples of P3HB-based resins include, for example, poly3-hydroxybutyrate (PHB), poly(3-hydroxybutyrate / 3-hydroxyvalerate) (PHBV), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHB3HV), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), (poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) It may contain one or more of the following: poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) (PHB4HB), poly(3-hydroxybutyrate-co-3-hydroxyoctadecanoate) (PHB3HO), poly(3-hydroxybutyrate-co-3-hydroxyoctadecanoate) (PHB3HOD), poly(3-hydroxybutyrate-co-3-hydroxydecanoate) (PHB3HD), poly(3-hydroxybutyrate-co-3-hydroxyvalate-co-3-hydroxyhexanoate) (PHB3HV3HH). The natural polymer may include one or more of the following: starch, cellulose, cellulose acetate, cellulose ester resin, starch, esterified starch, chitin, chitosan, gluten, gelatin, zein, soy protein, collagen, keratin, etc. The environmentally degradable resin may include, in addition to the polyester resins mentioned above, an environmentally degradable resin having a main chain containing an ester structure, such as polyamides containing an ester structure in the main chain. In addition to the natural polymers mentioned above, the environmentally degradable resin may also include, as a non-polyester resin, polyvinyl alcohol (PVA), polyamide 4 (PA4), aliphatic polycarbonates, and other biodegradable polycarbonates (PC).

[0035] Here, the environmentally degradable resin may include the same type of resin from aliphatic polyester resins, aromatic aliphatic polyester resins, and PHA resins, or it may include two or more different types. When different types are included, the environmentally degradable resin may include a combination of aliphatic polyester resin and aromatic aliphatic polyester resin, a combination of aliphatic polyester resin and PHA resin, a combination of aromatic aliphatic polyester resin and PHA resin, or a combination of aliphatic polyester resin, aromatic aliphatic polyester resin and PHA resin. In this case, the PHA resin may include at least P3HB resin, or it may include only P3HB resin. Furthermore, the environmentally degradable resin may contain the polyester resin described above alone, but it may also contain a copolymer of the polyester resin and the non-polyester resin, respectively.

[0036] The lower limit of the content of environmentally degradable resin contained in the layer-forming material is, for example, 10% by mass or more, preferably 12.5% ​​by mass or more, and more preferably 15% by mass or more, out of 100% by mass of the total content of ion-crosslinkable polymer, ion-crosslinking agent, and environmentally degradable resin. On the other hand, the upper limit of the content of environmentally degradable resin contained in the layer-forming material is not particularly limited, but may be 99.9% by mass or less, 99.7% by mass or less, or 99.5% by mass or less, out of 100% by mass of the total content of ion-crosslinkable polymer, ion-crosslinking agent, and environmentally degradable resin. Furthermore, the content of environmentally degradable resin A is, for example, 50 to 99% by mass, preferably 55 to 97.5% by mass, and more preferably 60 to 95% by mass, of 100% by mass of environmentally degradable resin. In this specification, "~" indicates that the upper and lower limits are included unless otherwise specified.

[0037] Ion-crosslinkable polymers are polymers that have ion-crosslinking groups. Ionic crosslinking agents are agents that themselves act as crosslinking sites in ionic crosslinking reactions. The ion-crosslinkable polymer and the ion-crosslinking agent may each consist of one type, or two or more types.

[0038] Ion-crosslinkable polymers can exist in powder or liquid form at room temperature and atmospheric pressure. Ionic crosslinking agents are available in powder or liquid form at room temperature and atmospheric pressure. Any combination of ion-crosslinkable polymers and ion-crosslinking agents can be used, but powdered ion-crosslinkable polymers and powdered ion-crosslinking agents may be used, or powdered ion-crosslinkable polymers and liquid ion-crosslinking agents may be used.

[0039] The shape of at least one of the ion-crosslinkable polymer and the ion-crosslinking agent may include one or more shapes selected from the group consisting of, for example, spherical, flattened, fibrous, polyhedral, crushed, and irregular shapes. Using such granular shapes can improve dispersibility in environmentally degradable resins. In this embodiment, the shape of the ion-crosslinkable polymer and the ion crosslinking agent can be measured by imaging observation such as SEM, TEM, AFM, or confocal microscopy. Alternatively, a laser diffraction / scattering particle distribution analyzer may be used.

[0040] Furthermore, the ion-crosslinkable polymer preferably contains at least one of the following components (A) and (B). On the other hand, ionic crosslinking agents are If the ion-crosslinkable polymer contains the following component (A), it is preferable that it also contains one or more components selected from the group consisting of the following components (B), (C), and (D): If the ion-crosslinkable polymer contains component (B) below, it is preferable that it also contains one or more components selected from the group consisting of components (A), (C), and (D) below. (A) Polyanions having monovalent or divalent or more anionic groups, or salts containing such polyanions (B) Polycations having monovalent or divalent or more cationic groups, or salts containing such polycations (C) Inorganic cations having monovalent or divalent or more cations, or salts containing one or more of such inorganic cations. (D) An anionic monomer having a monovalent or divalent or more anionic group, or an acid containing said anionic monomer

[0041] In this specification, the valency in (A), (B), and (D) refers to the valency of a single ionic functional group (ionic dissociation group) contained in the monomer or polymer. To illustrate with an example of ionic functional groups in the side chain of a polymer (macromolecule), carboxylic acids are monovalent, and dicarboxylic acids (oxalic acid, fumaric acid, etc.) are divalent. On the other hand, in the case of the valency in (C), sodium ions are monovalent, and calcium ions are divalent. To explain with specific examples, polyacrylic acid polymers are classified as "polyanions having monovalent anionic groups," while alkylphosphonic acid polymers are classified as "polyanions having divalent anionic groups." Furthermore, in polyacrylic acid, or polymers containing acrylic acid as a component, when acrylic acid forms a calcium salt, it is classified as a "polyanion-containing salt" in which a monovalent anionic group forms a salt with a divalent cation. Furthermore, in polymers containing phosphonic acid as a component, if the phosphonic acid forms a sodium salt, it is classified as a "polyanion-containing salt" in which the divalent anionic group forms a salt with a monovalent cation. Basically, polymers whose main chain has repeating structural units α with anionic groups are called "polyanions" (polymer anions). On the other hand, polymers whose main chain has repeating structural units β with cationic groups are called "polycations" (polymer cations). However, when the main chain of a polymer contains both repeating structural units α and β, a polymer is classified as a "polyanion" if the number of repeating structural units α in one molecule is equal to or greater than the number of repeating structural units β, while a polymer is classified as a "polycation" if the number of repeating structural units β in one molecule is greater than the number of repeating structural units α. Furthermore, substances that have an anionic group but do not have a repeating structural unit α that has an anionic group are referred to as "anionic monomers."

[0042] (A) The "polyanion having monovalent or divalent or more anionic groups" preferably includes one or more polyanions A1 selected from the group consisting of polysaccharides containing at least one of carboxylic acids, sulfonic acids, and phosphoric acids in their molecules, and complex carbohydrates containing polysaccharides. It is preferable that polyanion A1 contains at least one of carboxylic acids or sulfonic acids.

[0043] In this specification, a monosaccharide is a sugar composed of one type of sugar. Examples of sugars include glucose, mannose, galactose, glucosamine, galactosamine, xylose, sialic acid, glucuronic acid, iduronic acid, fucose, maltose, trehalose, and lactose. In this specification, a polysaccharide is a sugar composed of two or more monosaccharides linked by glycosidic bonds. A polysaccharide may be a homopolysaccharide, which has only one type of monosaccharide, or a heteropolysaccharide (sometimes called a complex polysaccharide), which has two or more types of monosaccharides. Furthermore, polysaccharides only need to have a sugar chain (main chain) consisting of repeating structures of constituent units derived from monosaccharides, and functional groups may or may not be formed on the side chains within the sugar chain. Examples of functional groups formed on the side chains include polar functional groups such as carboxyl groups, sulfonic acid groups, amide groups, acetyl groups, acetylamide groups, and amino groups. In this specification, a complex carbohydrate is a complex in which a polysaccharide is covalently bonded with other biocompounds other than sugars, such as proteins, lipids, and peptides. Examples of complex carbohydrates include biomacromolecules such as glycoproteins, proteoglycans, and glycolipids.

[0044] The polysaccharide in polyanion A1 may include one or more selected from the group consisting of, for example, alginic acid, carboxymethylcellulose, carrageenan, homogalacturonan, and glycosaminoglycans. Furthermore, the complex carbohydrate in polyanion A1 may include one or more selected from the group consisting of, for example, hyaluronic acid and chondroitin sulfate.

[0045] In another form, (A) "a polyanion having a monovalent or divalent or more anionic group" may include one or more polyanions A2 selected from the group consisting of ligninsulfonic acid and polyglutamic acid. That is, (A) may include polyanion A1 alone, polyanion A2 alone, or both polyanion A1 and polyanion A2. Furthermore, (A) a salt containing a polyanion having a monovalent or divalent or more anionic group may also include a salt of the polyanion with a monovalent cation, that is, an anionic compound formed by the salt formation of the anionic group of the polyanion with a monovalent cation, and may also include a salt of a polyanion having at least one of polyanion A1 and polyanion A2 with a monovalent cation. (A) The salt containing the polyanion may include one or more selected from the group consisting of sodium ions, potassium ions, ammonium ions, and phosphonium ions as the monovalent cation.

[0046] (B) Examples of "polycations having monovalent or divalent or more cationic groups" include polylysine and chitosan. Furthermore, (B) a salt containing a "polycation having monovalent or divalent or more cationic groups" may also include a salt of the polycation with a monovalent anion, that is, a cationic compound formed by a salt between the cationic groups of the polycation and a monovalent anion. (B) The salt containing the polycation may include, as the monovalent anion, one or more selected from the group consisting of chloride ions, hydroxide ions, fluoride ions, bromide ions, iodide ions, acetate ions, and nitrate ions.

[0047] The inorganic cation having a monovalent cation may include, for example, one or more selected from the group consisting of sodium ions, potassium ions, and ammonium ions. (C) The inorganic cation having a cation of 2 or higher valence may include, for example, one or more selected from the group consisting of calcium ions, magnesium ions, and aluminum ions. (C) A salt containing one or more "inorganic cations having monovalent or divalent or higher cations" may also contain a salt of one or more of those inorganic cations with a monovalent or divalent or higher inorganic anion, specifically, an ionic compound containing (C) an inorganic cation having a monovalent cation and / or (C) an inorganic cation having divalent or higher cation and one or more inorganic anions selected from the group consisting of sulfate ions, chloride ions, hydroxide ions, phosphate ions, carbonate ions, fluoride ions, bromide ions, iodide ions, nitrate ions, and acetate ions.

[0048] (D) An anionic monomer having a monovalent or divalent or more anionic group may include an anionic monomer having one or more carboxyl groups, or it may include an anionic monomer having a carboxylate group. (D) Acids containing an anionic monomer having a monovalent or divalent or greater anionic group may also contain an acid in which a proton is bonded to the anionic group of the anionic monomer. (D) Examples of acids containing the anionic monomer include anionic monomers having one or more carboxyl groups, such as oxalic acid, fumaric acid, ethylenediaminetetraacetic acid (EDTA), citric acid, and adipic acid. These may be used individually or in combination of two or more.

[0049] The weight-average molecular weight of at least one of component (A) and component (B) may be, for example, between 1,000 and 10,000,000. The molecular weights of the raw material monomers of component (A), the raw material monomers of component (B), and / or the anionic monomer of component (D) or the acid containing said anionic monomer may be, for example, between 1 and less than 1,000. In this specification, weight-average molecular weight is expressed as the value on a polystyrene basis.

[0050] Furthermore, the layer-forming material may include one or more selected from the group consisting of (X) hydrates of the ionic crosslinking agents described above, (Y) inorganic hydrates other than (X), and (Z) sodium silicate. (Y) The inorganic hydrate is not limited to any inorganic hydrate other than the (X) ion crosslinking agent described above, but it is preferable that it does not contain a salt hydrate selected from the group consisting of calcium ions, magnesium ions, and aluminum ions. (Y) Specific examples of inorganic hydrates include, for example, sodium carbonate decahydrate, sodium acetate trihydrate, sodium thiosulfate pentahydrate, disodium hydrogen phosphate dihydrate, disodium hydrogen phosphate heptahydrate, disodium hydrogen phosphate octahydrate, disodium hydrogen phosphate dodecahydrate, sodium dihydrogen phosphate monohydrate, sodium dihydrogen phosphate dihydrate, magnesium chloride hexahydrate, cobalt chloride hexahydrate, copper(II) sulfate pentahydrate, cobalt(II) iodide hexahydrate, tin(II) chloride dihydrate, iron(III) oxide hydrate, etc.

[0051] Furthermore, the layer-forming material may contain an ion-crosslinked material having at least ion crosslinks within its molecule, or it may not contain an ion-crosslinked material.

[0052] The ion-crosslinked material preferably contains an ion-crosslinked superabsorbent polymer. Ion-crosslinked superabsorbent polymers can absorb water and swell compared to conventional layer-forming materials such as polyolefin resins. Even if the ion-crosslinked superabsorbent polymer gels after absorbing water, it is thought that the fertilizer inside will dissolve in the water in the gel and be released to the outside. Furthermore, the ion-crosslinked superabsorbent polymer only needs to be able to absorb water; it is not necessary for it to absorb oils or other substances besides water. The weight-average molecular weight of the ion-crosslinked material and the ion-crosslinked superabsorbent polymer may be, for example, between 1,000 and 10,000,000.

[0053] For ion-crosslinked superabsorbent polymers, it is preferable to use a polymer salt containing at least two of the following (A') to (D'), and at least one of the following (i) to (vi). (i)(A') and (C'), (ii)(A'), (C'), and (D') (iii) (A'), (B'), and (C') (iv)(A') and (B') (v)(B') and (D') (vi)(A'), (B'), (C'), and (D') (A') Polyanions having monovalent or divalent or more anionic groups (B') Polycation having monovalent or divalent or more cationic groups (C')Polyvalent inorganic cation having a monovalent or divalent or more cation (D') Anionic monomer having a monovalent or divalent or greater anionic group

[0054] The layer-forming material can improve seawater degradability by containing the above-mentioned polymer salt as an ion-crosslinked water-absorbing polymer. Seawater decomposition refers to the property of the polymer salt to become more soluble in aqueous solvents due to an ion exchange reaction between ions present in seawater and ions in the polymer salt. When layer-forming materials dissolve and fragment in seawater, the increased surface area leads to an increased amount of microorganisms in contact with the surface, which is expected to accelerate the decomposition of the environmentally degradable resin.

[0055] The estimated mechanism of seawater degrading will be explained using the example of an ion-crosslinked superabsorbent polymer containing polymer salts (A') and (C') as the combination described in (i) above. However, the ion-crosslinked superabsorbent polymer is not limited to this. Ion-crosslinked polymers, which consist of alginate polymer (a polyanion with a monovalent anionic group) and calcium ions (a polyvalent inorganic cation), form an ionic crosslinked structure in water. However, in saltwater (seawater), the calcium ions exchange with sodium, causing the crosslinks to dissociate, making the polymer soluble in saltwater.

[0056] In another embodiment, it is preferable that the ion-crosslinked superabsorbent polymer is a polymer salt comprising at least one of (A') a polyanion having monovalent or divalent or more anionic groups and (D') an anionic monomer having monovalent or divalent or more anions. More specifically, it is more preferable to use a polymer salt comprising at least one of (i) and (ii) above.

[0057] Furthermore, the layer-forming material may or may not include an ion-crosslinked material obtained by the reaction of the above-mentioned ion-crosslinkable polymer and the above-mentioned ion-crosslinking agent, as an ion-crosslinked superabsorbent polymer.

[0058] The layer-forming material may contain, in addition to ion-crosslinkable polymers, ion-crosslinking agents, and environmentally degradable resins, other additives such as inorganic fillers, surfactants, sizing agents, and functional additives. These may be included individually or in any combination of two or more.

[0059] (Inorganic fillers) The inorganic filler can be any inorganic filler that is sparingly soluble or insoluble in water, and may include one or more selected from the group consisting of silica, talc, magnesium oxide, calcium oxide, alumina, titanium oxide, calcium carbonate, clay, potassium titanate, mica, glass flakes, whiskers, ferrite, iron oxide, zeolite, and magnesium sulfate. Among these, silica, talc, calcium carbonate, clay, mica, etc. are preferred from the viewpoint of price and availability.

[0060] The upper limit of the total inorganic filler content is, for example, 50% by mass or less, preferably 49% by mass or less, and more preferably 48% by mass or less, based on 100% by mass of the layer-forming material. This improves the film strength of the layer-forming material. The lower limit of the total inorganic filler content is, for example, 1% by mass or more, preferably 2% by mass or more, and more preferably 3% by mass or more, based on 100% by mass of the layer-forming material. This allows for low control of moisture permeability due to the water shielding effect.

[0061] The layer-forming material may contain at least one of a surfactant and / or a sizing agent, or it may contain neither. The surfactant and / or sizing agent can be used to control the dispersion state of the ion-crosslinked material. Examples of surfactants include anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. Among these, anionic surfactants and nonionic surfactants are preferred. Other sizing agents include natural sizing agents, synthetic sizing agents, reactive sizing agents, and special sizing agents. Among these, natural sizing agents and synthetic sizing agents are preferred. These may be included individually, or any combination of two or more may be included.

[0062] Here, we will explain the method for manufacturing the layer-forming material.

[0063] A method for producing a layer-forming material may include a step of melt-kneading raw material components, including the above-mentioned ion-crosslinkable polymer, the above-mentioned ion-crosslinking agent, and the above-mentioned environmentally degradable resin, using a kneading device to obtain a solid layer-forming material.

[0064] The order in which the raw material components are supplied to the kneading device is not particularly limited, but after the addition of the environmentally degradable resin, ion-crosslinkable polymers, ion-crosslinking agents, and other additives may be added depending on the application. For example, multiple raw material components may be added simultaneously or sequentially. If necessary, at least two of the components contained in the raw materials may be mixed beforehand before kneading the raw materials.

[0065] The temperature during melt mixing can be adjusted according to the melting or softening point of the environmentally degradable resin used, but for example, it may be 50°C to 300°C, preferably 70°C to 290°C, and more preferably 90°C to 280°C.

[0066] The raw materials may include water contained in each component of the raw materials, and / or water supplied from an external source separately from the raw materials. Examples of water contained in the components include adsorbed water and crystal water.

[0067] Furthermore, another method for producing a layer-forming material may include a step of obtaining a varnish-like layer-forming material comprising raw material components including the above-mentioned ion-crosslinkable polymer, the above-mentioned ion-crosslinking agent, and the above-mentioned environmentally degradable resin, and a solvent. If necessary, the raw materials may contain other additives depending on the intended use.

[0068] The solvent may include a solvent having a boiling point between 30°C and 210°C. As solvents, organic solvents (non-aqueous solvents) are preferred, and examples include halogenated solvents such as chloroform; aromatic solvents such as toluene; aliphatic solvents such as hexane; alicyclic solvents such as cyclohexane; ketone solvents such as acetone and MEK; ester solvents such as ethyl acetate; and alcoholic solvents such as methanol, ethanol, and isopropanol. These may be included individually or in any combination of two or more. In the case of the aqueous emulsion described later, a solvent containing water can be used, for example, one containing 50% or more by mass of water. As a solvent other than water, the non-aqueous solvents mentioned above may also be used. Furthermore, general emulsification processes such as homogenizing or mechanical stirring may be used during the production of aqueous emulsions.

[0069] In the process of obtaining a varnish-like layer-forming material, there are no particular restrictions on the order in which the components of the raw materials are mixed with the solvent. Heating may or may not be performed at any point during the mixing process.

[0070] Furthermore, the varnish-like layer-forming material may consist of a one-component liquid containing at least an ionic crosslinking agent, an ionic crosslinkable polymer, and a second liquid, or it may consist of a two-component liquid containing separately a first liquid containing at least an ionic crosslinking agent and a second liquid containing at least an ionic crosslinkable polymer. In the case of a two-component liquid, the environmentally degradable resin is contained in at least one of the first and second liquids.

[0071] The layering material can take the form of one of the following: solid, varnish, or viscous.

[0072] The solid layer-forming material may be in the form of a powder, granules, pellets, or briquettes. Depending on the form, known methods can be used for molding. Powders and granules can be produced by grinding, cutting, etc. If necessary, they may also be subjected to processing such as classification. Pellets can be manufactured by cutting strands that have been extruded from a molten mixture through a die. Briquettes can be manufactured by methods such as compressing powders or granules, or by molding molten mixtures using molds.

[0073] The viscous layer-forming material may be one in which at least one of its components has absorbed moisture and the forming material has gelled, or it may be one in which the forming material has softened due to the inclusion of a liquid component.

[0074] The layer-forming material set of this embodiment may include a first molding material and a second molding material. The first molding material and the second molding material in the set may be placed in separate containers. During use, the first molding material and the second molding material are mixed to obtain a layer-forming material.

[0075] The first molding material contains an environmentally biodegradable resin, while the second molding material contains a hydrophobic substance. The environmentally degradable resin includes environmentally degradable resin A, which has a main chain but no side chains. The hydrophobic substance comprises one or more hydrophobic substances X that satisfy at least one of the above (a) to (d). Furthermore, one or more elements selected from the group consisting of ion-crosslinkable polymers, ion-crosslinking agents, and inorganic fillers may be included in either the first molding material or the second molding material, or in both. Furthermore, the second molding material may contain one or more selected from the group consisting of defoamers, plasticizers, and surface modifiers for inorganic fillers. By manufacturing a first molding material that does not contain hydrophobic substances and a second molding material that contains hydrophobic substances separately, and storing and transporting each separately as needed, the handling of both materials can be improved.

[0076] The above set is A combination of a first molding material containing an ion-crosslinkable polymer, an ion-crosslinking agent, an environmentally degradable resin, and an inorganic filler, and a second molding material containing a hydrophobic substance. A combination of a first molding material containing an ion-crosslinkable polymer, an environmentally degradable resin, and an inorganic filler, and a second molding material containing an ion-crosslinking agent and a hydrophobic substance. A combination of a first molding material containing an environmentally degradable resin and an inorganic filler, and a second molding material containing an ion-crosslinkable polymer, an ion-crosslinking agent, and a hydrophobic substance. A combination of a first molding material containing an ion crosslinking agent, an environmentally degradable resin, and an inorganic filler, and a second molding material containing an ion crosslinkable polymer and a hydrophobic substance. The material may also include a combination of a first molding material containing an ionic crosslinking agent, an ionic crosslinkable polymer, an environmentally degradable resin, and an inorganic filler, and a second molding material containing an ionic crosslinkable polymer and a hydrophobic substance.

[0077] The first molding material in the set is preferably in the form of a solid, either powder, granules, pellets, or briquettes. The first molding material, comprising an ion-crosslinkable polymer, an ion-crosslinking agent, an environmentally degradable resin, and an inorganic filler, is manufactured separately from the second molding material. The solid first molding material may be manufactured in the same manner as the manufacturing of the solid layer-forming material described above.

[0078] The second molding material in the set may be solid, viscous, or liquid. The second molding material is obtained separately from the first molding material by mixing the above-mentioned components. Heating may be used during mixing if necessary.

[0079] Next, the covering structure of this embodiment will be described.

[0080] An example of the covering structure of this embodiment is: The above-mentioned items to be covered, The device may also include a coating layer that covers at least a portion of the surface of the object to be coated. The coating layer covers at least a portion or the entire surface of the object to be coated. The coating layer may include at least one layer made of the layer-forming material described above, and may also include one or more layers other than the layer made of the layer-forming material. When the coating layer has a multilayer structure, the layer made of the layer-forming material may be the innermost layer, the outermost layer, or an intermediate layer between the inner and outer layers.

[0081] The form of the material to be covered is solid or liquid in the atmosphere at 25°C. The shape of the material to be coated is not particularly limited, but may be granular, pelletized, briquette-shaped, or other irregular shapes. Among these, the material to be coated may be a granular solid or a granular liquid. The granular solid may be formed from powder or granules, or it may be spherical with a roughly circular or elliptical cross-section. The surface of the granular solid may be smooth or it may have surface irregularities.

[0082] The coating may include agricultural active ingredients such as fertilizer components and pesticide components, as described later. These may be included individually or in any combination of two or more. Furthermore, the material to be coated may contain some gas such as air or a solvent such as water.

[0083] (fertilizer ingredients) As for the fertilizer components, known components can be used, but for example, one or more of nitrogenous fertilizers, phosphorusous fertilizers, and potassiumous fertilizers can be used. Nitrogenous fertilizers include, for example, ammonium salts and nitrates, specifically ammonium sulfate, ammonium chloride, urea, calcium cyanamide, sodium nitrate, and ammonium nitrate. Examples of phosphate fertilizers include superphosphate, double superphosphate, fused phosphate fertilizer, and calcined phosphate fertilizer. Examples of potassium fertilizers include potassium chloride and potassium sulfate. In addition to the three fertilizers mentioned above, the fertilizer may also contain one or more known inorganic compounds containing other fertilizers (such as calcareous fertilizers, silicate fertilizers, manganese fertilizers, boron fertilizers, etc.) or inorganic nutrients.

[0084] The fertilizer components may also contain other components, as long as they do not impair the effects of the present invention. Other components may include, for example, carriers such as clay, kaolin, talc, bentonite, and calcium carbonate; binders such as polyvinyl alcohol, sodium carboxymethylcellulose, and starches; and, if necessary, surfactants such as polyoxyethylene nonylphenyl ether, molasses, animal oils, vegetable oils, hydrogenated oils, fatty acids, fatty acid metal salts, paraffin, waxes, and glycerin. These may be used individually or in combination of two or more.

[0085] For example, the form of the fertilizer component is not particularly limited; it just needs to be solid in the atmosphere at 25°C. An example of the form of fertilizer components would be granular fertilizer.

[0086] Granular fertilizers can be manufactured using known granulation methods such as fluidized bed granulation, rolling granulation, coated granulation, adsorption granulation, and coagulation granulation. However, the manufacturing method of granular fertilizers is not limited to these methods.

[0087] The coating layer that covers the fertilizer components may, if necessary, contain the following functional additives. Functional additives are not particularly limited as long as they are used as layering materials for fertilizers, but examples include fillers other than the inorganic fillers mentioned above, thickeners, adhesion promoters, surface modifiers (such as inorganic fillers), pH adjusters, crosslinking retarders (chelating agents), reinforcing materials, gas barrier agents, magnetic materials, decomposition control agents, defoaming agents, plasticizers, etc. These may be used individually or in combination of two or more. Furthermore, the layer-forming material may contain one or more of the functional additives. Among these, the layer-forming material preferably contains one or more selected from the group consisting of defoaming agents, plasticizers, and surface modifiers for inorganic fillers.

[0088] (Pesticide components) Pesticide components include fungicides, insecticides, and other chemicals (including materials that use such chemicals as raw materials or ingredients and are used for said control) used to control fungi, nematodes, mites, insects, rodents, and other animals, plants, or viruses (hereinafter referred to as "pests and diseases") that harm crops (including trees and agricultural and forestry products; hereinafter referred to as "crops, etc."), as well as plant growth regulators, germination inhibitors, and other chemicals used to enhance or suppress the physiological functions of crops, etc. However, there are no particular restrictions on pesticides as long as they are chemicals used for agricultural purposes, and any of these chemicals may be used, including insecticides, fungicides, and herbicides.

[0089] Next, a method for manufacturing the covering structure of this embodiment will be described.

[0090] An example of a method for manufacturing the coated structure of this embodiment may include a step of forming a coating layer on the surface of the object to be coated using the layer-forming material described above.

[0091] Known methods can be used to form the coating layer. Depending on the formation method, the form of the layer-forming material can be selected from those described above. For example, when using spray treatment as the formation method, a varnish-like form may be selected for the layer-forming material.

[0092] Methods for forming the coating layer can include known methods for coating the surface of solid particles, such as chemical methods including non-aqueous wet methods, aqueous wet methods, gas-phase reaction methods, and mechanical chemical methods, or physical methods such as mechanical surface treatment methods, laser ablation methods, air suspension coating methods, and spray drying methods. When coating an object to be coated with a layer-forming material, it is preferable to use a fluidized bed granulation method or a rolling granulation method. When applying to such manufacturing methods, it is preferable to use a varnish-like layer-forming material. However, it is not limited to this, and when using a solid layer-forming material, it can also be dissolved in a solvent and used in a varnished form. Alternatively, the object to be coated may be coated using an aqueous dispersion emulsion containing the layer-forming material.

[0093] Although embodiments of the present invention have been described above, these are merely examples, and various other configurations can be adopted. Furthermore, the present invention is not limited to the embodiments described above, and modifications, improvements, etc., within the scope that can achieve the objectives of the present invention are included in the present invention. [Examples]

[0094] The present invention will be described in detail below with reference to examples, but the present invention is not limited in any way to the descriptions of these examples.

[0095] <Manufacturing of layer-forming materials> (Reference example 1) Sodium alginate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as an ion-crosslinkable polymer, aluminum sulfate 14-18 hydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used as an ion-crosslinking agent, and calcium carbonate was used as an inorganic filler. These were ground and mixed in a mortar to obtain a mixture. The resulting mixture was mixed with polybutylene succinate (PBS), an environmentally biodegradable resin, while heating to obtain the layer-forming material of Reference Example 1. In Reference Example 1, the inorganic filler content in 100% by mass of the layer-forming material was 5% by mass.

[0096] (Examples 1-6) The layer-forming materials of Examples 1 to 6 were prepared in the same manner as in Reference Example 1, except that a hydrophobic substance was added to the obtained mixture as follows. Example 1: Paraffin wax (hydrocarbon wax, melting point 69°C, molecular weight 300-550) was added at a concentration of 10% by mass relative to the overall composition of the layer-forming material. Example 2: The above paraffin wax and carnauba wax (aliphatic ester wax, melting point 76°C, molecular weight 300-800) were each added at a concentration of 10% by mass relative to the overall composition of the layer-forming material. Example 3: The above paraffin wax and stearic acid (fatty acid, melting point 69-70°C, molecular weight 285) were each added at a concentration of 10% by mass relative to the overall composition of the layer-forming material. Example 4: The above paraffin wax and polyglycerin fatty acid ester (oils and fats, melting point 51-55°C, molecular weight 800-1200) were each added at a concentration of 10% by mass relative to the overall composition of the layer-forming material. Example 5: The above paraffin wax and microcrystalline wax (natural wax, melting point 87°C, molecular weight 500-800) were added to the overall composition of the layer-forming material at 8% by mass and 2% by mass, respectively. Example 6: The above paraffin wax and microcrystalline wax (natural wax, melting point 87°C, molecular weight 500-800) were added to the overall composition of the layer-forming material at concentrations of 16% by mass and 4% by mass, respectively. Example 7: The above microcrystalline wax was added at a concentration of 10% by mass relative to the overall composition of the layer-forming material.

[0097] <Characteristic Evaluation> (Crystallization test) Bottom area: 15.9cm2 A 4g hydrophobic substance was placed in an aluminum container with a height of 1.4cm and melted on a 90°C hot plate. After that, the container was moved off the hot plate and left to stand at room temperature (25°C). The time (in seconds) from immediately after the container was settling until the molten material lost its fluidity was measured and defined as the crystallization time. Paraffin wax: 45 seconds Carnauba wax: 45 seconds Stearic acid: 100 seconds • Polyglycerin fatty acid ester: 155 seconds • Microcrystalline wax: 40 seconds

[0098] (Bending test) A test specimen measuring 1 cm wide x 3 cm long x 0.2 cm thick was prepared by placing 1 g of hydrophobic material into a silicone mold, placing the mold on a 100°C hot plate, and then allowing it to melt and cool to room temperature. Using the obtained test specimens, a bending test was performed at room temperature (25°C), with a support distance of 2.4 cm and an indentation speed of 1 mm / min. The bending modulus (MPa), bending strength (MPa), and bending strain (%) were then measured. Paraffin wax: Flexural modulus 420 MPa, flexural strength 2.5 MPa, flexural strain 0.8% Carnauba wax: Flexural modulus 850 MPa, flexural strength 4.5 MPa, flexural strain 0.6% • Polyglycerin fatty acid ester: Flexural modulus 260 MPa, flexural strength 1.5 MPa, flexural strain 0.5% Paraffin wax (80% by mass) and microcrystalline wax (20% by mass): Flexural modulus 470 MPa, flexural strength 4.1 MPa, flexural strain 1.5% Microcrystalline wax: Flexural modulus 390 MPa, flexural strength 4.0 MPa, flexural strain 1.4%

[0099] <Evaluation of blocking properties> The blocking score was evaluated following the procedure below. A 55mm stirring bar and 5g of water-soluble urea particles (diameter: approximately 2-3mm) were added to a container with a base diameter of φ60mm. The container was placed on a hot plate and heated to 90°C. While stirring with a stirring bar at 200 rpm, 0.75 mL of varnish solution was added dropwise, and the mixture was stirred for 1 minute. The above procedure, from dropping the varnish solution to stirring, was repeated, and the number of times until the particles blocked each other was measured. This number was defined as the blocking score. A higher blocking score indicates that blocking is more suppressed.

[0100] The layer-forming materials in Examples 1-7 showed a higher blocking score compared to Reference Example 1, demonstrating the ability to suppress the occurrence of blocking. Furthermore, Examples 2-7 showed a higher blocking score than Example 1.

Claims

1. An environmentally degradable resin containing an environmentally degradable resin A having a main chain but no side chains, One or more selected from the group consisting of ion-crosslinkable polymers, ion-crosslinking agents, and inorganic fillers, A layer-forming material comprising one or more hydrophobic substances selected from the group consisting of waxes, oils and fats, and fatty acids.

2. A layer-forming material according to claim 1, The hydrophobic material comprises one or more hydrophobic materials X that satisfy at least one of the following conditions (a) to (d), in a layer-forming material. (a) The molecular weight is 15 or more and 20,000 or less. (b) The crystallization time, as measured by the crystallization test described below, is between 1 second and 300 seconds. (Crystallization test) Bottom area: 15.9cm ２ A 1.4 cm high aluminum container is placed in 4 g of the hydrophobic substance X and melted on a 90°C hot plate. After that, the container is moved off the hot plate and left to stand at room temperature (25°C). The time (in seconds) from immediately after the container is settling until the molten material loses its fluidity is measured and defined as the crystallization time. (c) Having one of the following characteristics as measured according to the bending test below: a bending modulus of 1000 MPa or less, a bending strength of 7 MPa or less, or a bending strain of 0.1% or more. (Bending test) A test specimen measuring 1 cm in width, 3 cm in height, and 0.2 cm in thickness is prepared by placing 1 g of the hydrophobic substance X into a silicone mold, placing the mold on a 100°C hot plate, and allowing it to melt and then cool to room temperature. Using the obtained test specimens, a bending test was performed at room temperature (25°C), with a support distance of 2.4 cm and an indentation speed of 1 mm / min, and the bending modulus (MPa), bending strength (MPa), and bending strain (%) were measured. (d) The HSP value for the environmentally degradable resin A is 6.0 or higher.

3. A layer-forming material according to claim 1 or 2, The hydrophobic substance comprises one or more selected from the group consisting of hydrocarbon waxes, fatty acid waxes, higher alcohol waxes, glycerin fatty acid esters, and fatty acids, and is a layer-forming material.

4. A layer-forming material according to claim 1 or 2, A layer-forming material wherein the hydrophobic substance comprises a hydrophobic substance X' having an HSP value of less than 6.0 relative to the environmentally degradable resin A.

5. A layer-forming material according to claim 1 or 2, A layer-forming material wherein at least one of the hydrophobic substances has a melting point of 110°C or lower.

6. A layer-forming material according to claim 1 or 2, A layer-forming material comprising one or more selected from the group consisting of an antifoaming agent, a plasticizer, and a surface modifier for the inorganic filler.

7. A layer-forming material according to claim 1 or 2, A layer-forming material wherein the inorganic filler comprises one or more selected from the group consisting of silica, talc, magnesium oxide, calcium oxide, alumina, titanium oxide, calcium carbonate, clay, potassium titanate, mica, glass flakes, whiskers, ferrite, iron oxide, zeolite, and magnesium sulfate.

8. A layer-forming material according to claim 1 or 2, The ion-crosslinkable polymer comprises at least one of the following components (A) and (B): If the ion-crosslinkable polymer contains the following component (A), the ion-crosslinking agent contains one or more selected from the group consisting of the following components (B), (C), and (D): If the ion-crosslinkable polymer contains the following component (B), the ion-crosslinking agent is a layer-forming material comprising one or more selected from the group consisting of the following components (A), (C), and (D). (A) Polyanions having monovalent or divalent or more anionic groups, or salts containing such polyanions (B) Polycations having monovalent or divalent or more cationic groups, or salts containing such polycations (C) an inorganic cation having a monovalent or divalent or more cations, or a salt containing one or more of such inorganic cations. (D) An anionic monomer having a monovalent or divalent or more anionic group, or an acid containing said anionic monomer

9. A layer-forming material according to claim 1 or 2, A layer-forming material used to form a coating layer on the surface of an object to be coated.

10. A layer-forming material according to claim 9, The aforementioned coating target is a layer-forming material containing agricultural active ingredients.

11. The object to be covered, A coating layer that covers at least a portion of the surface of the object to be coated, A coating structure wherein the coating layer comprises the layer-forming material described in claim 1 or 2.

12. A method for manufacturing a coated structure, comprising the step of forming a coating layer on the surface of an object to be coated using the layer-forming material described in claim 1 or 2.

13. A layer-forming material set comprising a first molding material and a second molding material, The first molding material includes an environmentally degradable resin, and the environmentally degradable resin includes an environmentally degradable resin A having a main chain but no side chains. The second molding material contains a hydrophobic substance, A layer-forming material set comprising one or more selected from the group consisting of ion-crosslinkable polymers, ion-crosslinking agents, and inorganic fillers, which are included in either or both of the first molding material and the second molding material.

14. A layer-forming material set according to claim 13, A layer-forming material set in which the first molding material is in the form of a powder, granules, pellets, or briquettes.

15. A layer-forming material set according to claim 13 or 14, A layer-forming material set wherein the second molding material comprises one or more selected from the group consisting of an antifoaming agent, a plasticizer, and a surface modifier for the inorganic filler.