Coating material and method for producing the same, coated granular fertilizer, coated granular pesticide, and coated seed

Abstract

To provide a coating material having high soil degradability and a method for producing the same; a coated granular fertilizer including a granular fertilizer coated with the coating material; a coated granular pesticide including a granular pesticide coated with the coating material; and a coated seed including a seed coated with the coating material.SOLUTION: A coating material includes a urethane resin having a polyol structural unit derived from a polyol and a polyisocyanate structural unit derived from a polyisocyanate. The polyol includes a polyester ether polyol formed by copolymerizing an alkylene oxide having an epoxy ring and 2 to 20 carbon atoms, and a compound other than the alkylene oxide, the compound having an ester bond and an oxygen-containing heterocyclic structure, with a compound having at least one active hydrogen atom in one molecule, in the presence of a double metal cyanide complex catalyst.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a coating material, a method for producing the same, a coated granular fertilizer, a coated granular pesticide, and a coated seed, and more particularly, to a coating material, a method for producing the same, a coated granular fertilizer containing a granular fertilizer coated with the coating material, a coated granular pesticide containing a granular pesticide coated with the coating material, and a coated seed containing a seed coated with the coating material.

Background Art

[0002] Conventionally, a urethane resin obtained by polymerizing a polyester polyol obtained by polymerizing caprolactone and a polyisocyanate with an initiator compound having a hydroxyl group has been used as a coating agent for coated fertilizers. (For example, see Patent Document 1). Further, in the presence of a double metal cyanide complex catalyst (hereinafter also referred to as "DMC catalyst"), a polyester ether poly(mono)ol is produced by ring-opening addition polymerization (copolymerization) of an alkylene oxide and a compound having an oxygen-containing heterocyclic structure with an initiator compound having a hydroxyl group. (For example, see Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the urethane resin described in Patent Document 1 has a problem that although it has biodegradability, its soil degradability is not sufficient. In addition, the polyester ether poly(mono)ol produced by the production method described in Patent Document 2 had a problem that it could not be directly used as a resin for molding. Under such circumstances, the development of a coating material containing a urethane resin having high soil degradability has been desired.

[0005] The present invention has been made to solve such problems, and provides a coating material having high soil degradability and a method for producing the same, a coated granular fertilizer containing granular fertilizer coated with the coating material, a coated granular pesticide containing granular pesticide coated with the coating material, and a coated seed containing seeds coated with the coating material. [Means for Solving the Problems]

[0006] As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using a coating material containing a urethane resin having a polyol structural unit derived from a polyol containing a predetermined polyester ether polyol and a polyisocyanate structural unit derived from a polyisocyanate, and have completed the present invention. The present invention is as follows [1] to

[16] . [1] A coating material containing a urethane resin having a polyol structural unit derived from a polyol and a polyisocyanate structural unit derived from a polyisocyanate, wherein the polyol is a compound having at least one active hydrogen atom in one molecule in the presence of a double metal cyanide complex catalyst, copolymerized with an alkylene oxide having 2 to 20 carbon atoms having an epoxy ring and a compound other than the alkylene oxide, the compound having an ester bond and an oxygen-containing heterocyclic structure, the coating material containing a polyester ether polyol. [2] The coating material according to [1] above, wherein the urethane resin contains 20 to 65% by mass of a structural unit based on propylene oxide. [3] The coating material according to [1] or [2] above, wherein the ester group concentration of the urethane resin is 5 to 30% by mass. [4] The coating material according to any one of [1] to [3] above, wherein the compound having at least one active hydrogen atom in one molecule has one or more and twelve or less hydroxyl groups and a mass average molecular weight (Mw) of 18 to 20,000. [5] The coating material according to any one of [1] to [4] above, wherein the mass ratio of the alkylene oxide to the compound having an oxygen-containing heterocyclic structure (alkylene oxide: compound having an oxygen-containing heterocyclic structure) is 35:65 to 99:1. [6] The coating material according to any one of [1] to [5] above, wherein the compound having an oxygen-containing heterocyclic structure is at least one selected from the group consisting of ε-caprolactone and phthalic anhydride. [7] The coating material according to any one of [1] to [6] above, wherein the alkylene oxide is at least one selected from the group consisting of ethylene oxide and propylene oxide. [8] The coating material according to any one of [1] to [7] above, wherein the hydroxyl value of the polyester ether polyol is 30 to 200 mgKOH / g. [9] The coating material according to any one of [1] to [8] above, wherein the number average molecular weight (Mn) of the polyester ether polyol is 900 to 5,000.

[10] The coating material according to any one of [1] to [9] above, wherein the molecular weight distribution (Mw / Mn) of the polyester ether polyol is 1.08 to 1.50.

[11] The coating material according to any one of [1] to

[10] above, wherein the isocyanate index of the urethane resin is 80 to 300.

[12] A coated granular fertilizer containing the granular fertilizer coated with the coating material according to any one of [1] to

[11] above.

[13] A coated granular pesticide containing the granular pesticide coated with the coating material according to any one of [1] to

[11] above.

[14] A coated seed containing the seed coated with the coating material according to any one of [1] to

[11] above.

[15] A method for producing a coating material for producing the coating material according to any one of [1] to

[11] above, which comprises reacting a polyol constituting the polyol structural unit with a polyisocyanate constituting the polyisocyanate structural unit to obtain a urethane resin.

[16] The method for producing a coating material according to

[15] above, wherein the mass ratio of the polyol to the polyisocyanate (polyol / polyisocyanate) is 1 to 20.

Effects of the Invention

[0007] According to the present invention, there are provided a coating material having high soil decomposability and a method for producing the same, a coated granular fertilizer containing the granular fertilizer coated with the coating material, a coated granular pesticide containing the granular pesticide coated with the coating material, and a coated seed containing the seed coated with the coating material.

Modes for Carrying Out the Invention

[0008] The meanings and definitions of the terms in this specification are as follows. In this specification, "alkylene oxide" means "a compound in which the unsaturated group of a monoalkene is epoxidized". In this specification, a numerical range represented by "~" means a numerical range having the numerical values before and after "~" as the lower limit value and the upper limit value. In this specification, for preferred numerical ranges (for example, ranges such as content), the lower limit value and the upper limit value described stepwise can be combined independently. For example, from the description "preferably 10 to 90, more preferably 30 to 60", it is also possible to combine the "preferred lower limit value (10)" and the "more preferred upper limit value (60)" to obtain "10 to 60". In this specification, "alkylene oxide having 2 to 20 carbon atoms having an epoxy ring" may be simply referred to as "alkylene oxide (A)". In this specification, "a compound other than (the) alkylene oxide and having an ester bond and an oxygen-containing heterocyclic structure" may be simply referred to as "compound (B)". As used herein, the "isocyanate index" means 100 times the molar ratio (isocyanate group / hydroxyl group) of the isocyanate groups in the polyisocyanate to the hydroxyl groups in the polyol when obtaining the urethane resin. In this specification, the EO content (mass %), PO content (mass %), and ester group concentration (mass %) are calculated from the charged amounts during the production of the urethane resin, etc. However, the urethane resin is dissolved in a deuterated solvent, 1 and it can also be analyzed using 1H-NMR. When the urethane resin is insoluble in the deuterated solvent, the urethane resin and an aqueous solution of sodium hydroxide or potassium hydroxide are added to a pressure-resistant autoclave, hydrolyzed overnight in an oven set at 80 to 110 °C, and then the alkali hydrolyzate of the urethane resin is dissolved in the deuterated solvent 1 By analyzing using 1H-NMR, the EO content (mass %), PO content (mass %), and ester group concentration (mass %) can also be measured from the urethane resin. Normally, since the value calculated from the charged amounts during the production of the urethane resin, etc. and 1 the analytical value using 1H-NMR are substantially the same value, the value calculated from the charged amounts during the production of the urethane resin, etc. may be regarded as the EO content (mass %), PO content (mass %), and ester group concentration (mass %). However, when the value calculated from the charged amounts during the production of the urethane resin, etc. and 1 the analytical value using 1H-NMR do not match, 1 the analytical value using 1H-NMR is taken as the EO content (mass %), PO content (mass %), and ester group concentration (mass %).

[0009] [Coating material] The coating material of the present invention contains a urethane resin having a polyol structural unit derived from a polyol and a polyisocyanate structural unit derived from a polyisocyanate, and optionally contains other components.

[0010] [Urethane resin] The urethane resin may be obtained by reacting an isocyanate-terminated prepolymer obtained by reacting a polyol and a polyisocyanate with water (moisture in the air), or may also be obtained by reacting a polyol, a polyisocyanate, and other optional components such as a crosslinking agent. Here, examples of the crosslinking agent include dipropylene glycol, 1,5-pentanediol, and the like.

[0011] The content of the structural unit based on ethylene oxide (hereinafter referred to as "EO") in the urethane resin is not particularly limited. However, from the viewpoint of imparting appropriate hydrophilicity to the urethane resin and promoting soil decomposability, it is preferably 0% by mass to 80% by mass, more preferably 0% by mass to 50% by mass, and particularly preferably 0% by mass to 30% by mass. The measurement method of the content of the structural unit based on EO in the urethane resin is the method described in the examples.

[0012] The content of the structural unit based on propylene oxide (hereinafter referred to as "PO") in the urethane resin is not particularly limited. However, from the viewpoint of imparting appropriate hydrophobicity to the urethane resin and adjusting soil decomposability, it is preferably 20 to 65% by mass, more preferably 30 to 50% by mass, and particularly preferably 40 to 50% by mass. The measurement method of the content of the structural unit based on PO in the urethane resin is the method described in the examples.

[0013] The ester group concentration in the urethane resin is not particularly limited as long as it is 5 to 30% by mass. However, from the viewpoint of improving the soil decomposability of the urethane resin, it is preferably 10 to 25% by mass, and particularly preferably 15 to 24% by mass. The measurement method of the ester group concentration in the urethane resin is the method described in the examples.

[0014] The isocyanate index of the urethane resin is not particularly limited. However, from the viewpoints of resin viscosity and cost, it is preferably 80 to 300, more preferably 140 to 260, and particularly preferably 180 to 220.

[0015] The content of the urethane resin in the covering material is not particularly limited, but is preferably 40% by mass or more, more preferably 70% by mass or more, still more preferably 90% by mass or more, and particularly preferably 100% by mass.

[0016] <<Polyol>> The polyol is not particularly limited as long as it contains a polyester ether polyol, and may contain other polyols such as polyethylene poly(mono)ol, polypropylene poly(mono)ol, polyoxyethylene polyoxypropylene poly(mono)ol, polyester polyol, and polytetramethylene polyol.

[0017] The polyester ether polyol is not particularly limited as long as it is obtained by copolymerizing a specific initiator compound with a specific alkylene oxide and a compound having a specific oxygen-containing heterocyclic structure in the presence of a DMC catalyst, and usually has an ether bond and an ester bond randomly.

[0018] The content of the structural unit based on EO in the polyester ether polyol is not particularly limited, but from the viewpoint of imparting appropriate hydrophilicity to the urethane resin and promoting soil degradability, it is preferably 0% by mass to 90% by mass, more preferably 0% by mass to 60% by mass, and particularly preferably 0% by mass to 40% by mass. The measurement method of the content of the structural unit based on EO in the polyester ether polyol is the method described in the examples.

[0019] The content of the structural unit based on PO in the polyester ether polyol is not particularly limited, but from the viewpoint of imparting appropriate hydrophilicity to the urethane resin and promoting soil degradability, it is preferably 40 to 85% by mass, more preferably 50 to 80% by mass or less, and particularly preferably 60 to 75% by mass. The measurement method of the content of the structural unit based on PO in the polyester ether polyol is the method described in the examples.

[0020] The ester group concentration in the polyester ether polyol is not particularly limited, but from the viewpoint of improving the soil degradability of the urethane resin, it is preferably 5 to 45% by mass, more preferably 20 to 40% by mass, and particularly preferably 28 to 36% by mass. The method for measuring the ester group concentration in the polyester ether polyol is as described in the examples.

[0021] The hydroxyl value of the polyester ether polyol is not particularly limited, but from the viewpoints of low viscosity and ease of handling during extraction after production, and cost reduction associated with reducing the amount of isocyanate used, it is preferably 30 to 200 mgKOH / g, more preferably 100 to 190 mgKOH / g, and particularly preferably 140 to 180 mgKOH / g. The method for measuring the hydroxyl value of the polyester ether polyol is as described in the examples.

[0022] The mass average molecular weight (Mw) of the polyester ether polyol is not particularly limited, but from the viewpoint of handling viscosity, 900 to 5,000 is preferable, 1,000 to 3,000 is more preferable, and 1,000 to 1,500 is particularly preferable. The method for measuring the mass average molecular weight (Mw) is as described in the examples.

[0023] The number average molecular weight (Mn) of the polyester ether polyol is not particularly limited, but from the viewpoint of handling viscosity, 900 to 5,000 is preferable, 1,000 to 3,000 is more preferable, and 1,000 to 1,500 is particularly preferable. The method for measuring the number average molecular weight (Mn) is as described in the examples.

[0024] The molecular weight distribution (Mw / Mn) of the polyester ether polyol is not particularly limited, but from the viewpoint of handling viscosity, 1.08 to 1.50 is preferable, 1.08 to 1.30 is more preferable, and 1.08 to 1.20 is particularly preferable. The method for measuring the molecular weight distribution (Mw / Mn) is as described in the examples.

[0025] The content of the polyester ether polyol in the polyol is not particularly limited, but is preferably 40% by mass or more, more preferably 70% by mass or more, still more preferably 90% by mass or more, and particularly preferably 100% by mass.

[0026] (Double metal cyanide complex catalyst (DMC catalyst)) The double metal cyanide complex catalyst is not particularly limited as long as it is a DMC catalyst commonly used in the production of polyester ether polyols. Examples thereof include compounds represented by the following general formula (1).

[0027] M 1 a [M 2 b (CN) c d e(M 3 f X g )h(H2O)i(L)···(1) (In formula (1), M 1 ~M 3 represents a metal, X represents a halogen atom, L represents an organic ligand, and a, b, c, d, e, f, g, h, i represent numbers that can vary depending on the valence of the metal, the coordination number of the organic ligand, etc., respectively.)

[0028] In the above general formula (1), the metals represented by M 1 and M 3 are each preferably a metal selected from the group consisting of Zn(II), Fe(II), Fe(III), Co(II), Ni(II), Mo(IV), Mo(VI), Al(III), V(V), Sr(II), W(IV), W(VI), Mn(II), Cr(III), Cu(II), Sn(II), and Pb(II), and more preferably Zn(II) or Fe(II). In the above general formula (1), M 2 ​As the metal represented by [formula], a metal selected from Fe(II), Fe(III), Co(II), Co(III), Cr(II), Cr(III), Mn(II), Mn(III), Ni(II), V(IV), and V(V) is preferred, and Co(III) or Fe(III) is more preferred. Note that the Roman numerals II, III, IV, V, etc. in parentheses following the element symbol of the metal indicate the valence. In the above general formula (1), M 1 and M 3 may be the same as or different from each other, but it is preferred that they are the same as each other.

[0029] In the above general formula (1), as L representing the organic ligand, at least one compound selected from the group consisting of alcohol, ether, ketone, ester, amine, and amide is preferred. Among these, water-soluble organic ligands such as tert-butyl alcohol, n-butyl alcohol, sec-butyl alcohol, iso-butyl alcohol, tert-pentyl alcohol, iso-pentyl alcohol, N,N-dimethylacetamide, ethylene glycol dimethyl ether (also called glyme), diethylene glycol dimethyl ether (also called diglyme), triethylene glycol dimethyl ether (also called triglyme), ethylene glycol mono-tert-butyl ether, iso-propyl alcohol, and dioxane are more preferred. As dioxane, either 1,4-dioxane or 1,3-dioxane may be used, but 1,4-dioxane is preferred.

[0030] In the DMC catalyst, more preferable organic ligand L is tert-butyl alcohol alone or a combination of tert-butyl alcohol and the compounds exemplified above. Among these, tert-butyl alcohol alone and the combination of tert-butyl alcohol and ethylene glycol mono-tert-butyl ether are particularly preferable. The DMC catalyst having such an organic ligand exhibits high catalytic activity in the copolymerization reaction (ring-opening addition polymerization reaction) of alkylene oxide or the like with respect to the initiator compound used in the production of polyester ether polyol, and a polyester ether polyol having a narrow molecular weight distribution and low viscosity can be obtained.

[0031] The DMC catalyst can be produced by a conventionally known production method. In the conventionally known production method, there is no particular limitation, and it can be produced using any production method. As a method for producing the DMC catalyst having an organic ligand preferably used in the present invention, for example, the method described in JP-A-2003-117403 can be used. More specifically, (i) an organic ligand is coordinated to a reaction product obtained by reacting a metal halide salt with cyanometalate acid and / or an alkali metal cyanometalate in an aqueous solution, then the generated solid component is separated, and the separated solid component is further washed with an aqueous solution of the organic ligand, or (ii) a metal halide salt is reacted with cyanometalate acid and / or an alkali metal cyanometalate in an aqueous solution of the organic ligand, the obtained reaction product (solid component) is separated, and the separated solid component is further washed with an aqueous solution of the organic ligand. Examples thereof include a method of filtering and separating the obtained cake (solid component) and further drying it.

[0032] The metal constituting the cyanometalate of the alkali metal cyanometalate used when producing the DMC catalyst is preferably at least one metal selected from the group consisting of Fe(II), Fe(III), Co(II), Co(III), Cr(II), Cr(III), Mn(II), Mn(III), Ni(II), V(IV), and V(V), more preferably Co(III) or Fe(III), and particularly preferably Co(III).

[0033] As the cyanometalate acid and alkali metal cyanometalate used as raw materials for producing the DMC catalyst, H3[Co(CN)6], Na3[Co(CN)6], or K3[Co(CN)6] is preferable, and Na3[Co(CN)6] or K3[Co(CN)6] is more preferable.

[0034] Furthermore, in the method for producing the DMC catalyst, at a stage before filtering and separating the cake, a polyether compound is mixed with a liquid in which a solid component is dispersed in an aqueous solution of an organic ligand, and water and excess organic ligand are distilled off from the obtained mixed liquid, whereby a slurry-like DMC catalyst mixture in which the DMC catalyst is dispersed in the polyether compound (hereinafter, also referred to as "slurry-like DMC catalyst") can be prepared.

[0035] The polyether compound used for preparing the slurry-like DMC catalyst can be separated from the DMC catalyst during the production of the polyester ether polyol, and the separated DMC catalyst can be used for the production of the polyester ether polyol. This polyether compound is preferably used as part or all of the initiator compound described later. In this polyether compound, alkylene oxide (A) and compound (B) are copolymerized to obtain the target polyester ether polyol. The polyether compound used for this purpose preferably has a hydroxyl group number of 1 to 8 and a number average molecular weight (Mn) of 300 to 5,000. This is preferable because it increases the catalytic activity of the DMC catalyst and does not increase the viscosity of the slurry-like DMC catalyst, making it easy to handle.

[0036] The addition amount of the DMC catalyst is not particularly limited, but from the viewpoint of narrowing the molecular weight distribution, it is preferably 10 to 500 mass ppm, more preferably 20 to 400 mass ppm, and even more preferably 30 to 300 mass ppm based on 100 mass% of the produced polyester ether polyol.

[0037] (Initiator compound) The initiator compound used in the production of polyester ether polyol is a compound having at least one active hydrogen atom in one molecule. As the compound having an active hydrogen atom, a compound having a hydroxyl group is preferable in that it does not inhibit the activity of the DMC catalyst. More specifically, a compound having 1 to 12 hydroxyl groups and a mass average molecular weight (Mw) of 18 to 20,000 is preferable.

[0038] Specific examples of the initiator compound include monohydric alcohols such as methanol, ethanol, 2-propanol, n-butanol, iso-butanol, 2-ethylhexanol, decyl alcohol, lauryl alcohol, tridecanol, cetyl alcohol, stearyl alcohol, oleyl alcohol; water; dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-cyclohexanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanediol, polyethylene glycol, polypropylene glycol, polycarbonate diol, polytetramethylene glycol; polyhydric alcohols having a trivalent or higher valence such as glycerin, diglycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol; saccharides or their derivatives such as glucose, sorbitol, dextrose, fructose, sucrose, methyl glucoside; phenols such as bisphenol A, bisphenol F, bisphenol S, novolak, resorcin, resorcinol; esters such as polycaprolactone, polylactic acid; etc. These compounds can be used alone or in combination of two or more.

[0039] In addition, a polyester ether polyol obtained by polymerizing these compounds with an alkylene oxide (A) and a compound (B) by a known method can also be used as the initiator compound. The number of hydroxyl groups per molecule of the polyester ether polyol is not particularly limited, but is preferably 1 to 12, more preferably 2 to 8, and particularly preferably 2 to 6. When an initiator compound having a hydroxyl group number below the above upper limit is used, the molecular weight distribution of the resulting polyester ether polyol tends to be narrow. When two or more compounds are used in combination as the initiator compound, the average number of hydroxyl groups per molecule is preferably 1 to 12, more preferably 2 to 8, and particularly preferably 2 to 4.

[0040] The mass average molecular weight (Mw) of the initiator compound is not particularly limited, but is preferably 18 to 20,000, more preferably 100 to 5,000, and particularly preferably 300 to 1,000. By using an initiator compound having a mass average molecular weight (Mw) of 100 or more, the time until the initial step with alkylene oxide in the presence of a DMC catalyst starts can be shortened. When an initiator compound having a mass average molecular weight (Mw) of 5,000 or less is used, the viscosity is not too high when charging the initiator compound into the reactor, which is suitable. The molecular weight distribution (mass average molecular weight (Mw) / number average molecular weight (Mn)) of the initiator compound is not particularly limited, and from the viewpoint of low handling viscosity, 1.000 to 2.000 is preferable, 1.100 to 1.700 is more preferable, and 1.200 to 1.500 is particularly preferable.

[0041] In addition, when the initiator compound is composed only of molecules of the same molecular weight, such as a low molecular alcohol, the molecular weight obtained from the chemical formula is taken as the mass average molecular weight (Mw). The mass average molecular weight (Mw) of the initiator compound is lower than the mass average molecular weight (Mw) of the polyester ether polyol obtained using it. The difference between the mass average molecular weight of the initiator compound and the mass average molecular weight of the polyester ether polyol obtained using it (that is, the amount of units obtained by ring-opening of alkylene oxide (A) and compound (B)) is preferably 500 or more, and particularly preferably 700 or more. When the difference in mass average molecular weight is 500 or more, the polymerization amount in the presence of a DMC catalyst increases, so that the merit of polymerization in the presence of a DMC catalyst is easily obtained.

[0042] When using the resulting polyester ether polyol as a raw material for resins such as polyurethanes or modified silicones, the number of hydroxyl groups in the polyester ether polyol is preferably from 1 to 12, more preferably from 2 to 8, and particularly preferably from 2 to 6. Therefore, the number of hydroxyl groups in the initiator compound for producing such a polyester ether polyol is preferably from 1 to 12, more preferably from 2 to 8, and particularly preferably from 2 to 6. When using two or more initiator compounds, the average number of hydroxyl groups in the initiator compounds is preferably from 1.5 to 8, more preferably from 1.8 to 6, and particularly preferably from 1.8 to 3.

[0043] The addition amount of the initiator compound is not particularly limited, but from the viewpoints of sufficiently performing stirring and making use of the free volume of the reaction vessel for the copolymerization reaction as much as possible, it is preferably 1 to 30% by volume of the reaction vessel volume, more preferably 5 to 20% by volume of the reaction vessel volume, and particularly preferably 6 to 15% by volume of the reaction vessel volume.

[0044] (Alkylene oxide (A), compound (B)) The compounds copolymerized with the initiator compound are alkylene oxide (A) and compound (B). "Compound (B)" is a compound having an oxygen-containing heterocyclic structure composed of two or more carbon atoms and one or more oxygen atoms, and contains components derived from ester bonds such as cyclic esters and acid anhydrides.

[0045] As a method of using alkylene oxide (A) and compound (B) in combination, specifically, there are a method of reacting a mixture of alkylene oxide (A) and compound (B) with the initiator compound, and a method of reacting both separately, etc. In the case where compound (B) is a compound that is difficult to copolymerize alone (such as carboxylic acid anhydride), it is preferably used after mixing with alkylene oxide (A).

[0046] -Alkylene oxide having 2 to 20 carbon atoms and an epoxy ring (alkylene oxide (A))- The carbon number of the alkylene oxide (A) is not particularly limited as long as it is from 2 to 20, and is preferably from 2 to 6. Examples of the alkylene oxide (A) include EO, PO, 1,2-butene oxide, 2,3-butene oxide, epoxidized products of α-olefins having 5 to 12 carbon atoms, and the like. The alkylene oxide (A) to be reacted with the initiator compound may be two or more kinds. When two or more kinds are used, their mixture may be reacted, or they may be reacted separately. The alkylene oxide (A) is preferably at least one selected from the group consisting of EO and PO. EO and PO can be reacted alone, or their mixture can be reacted, or they can be reacted separately.

[0047] The addition amount of the alkylene oxide (A) is not particularly limited, but from the viewpoint of ensuring soil degradability, it is preferably from 10 to 95 parts by mass, more preferably from 15 to 85 parts by mass, and even more preferably from 20 to 75 parts by mass, based on 100 parts by mass of the produced polyester ether polyol.

[0048] -Compound (B) having an oxygen-containing heterocyclic structure other than an alkylene oxide having an ester bond- Examples of the compound (B) include cyclic esters, acid anhydrides, cyclic carbonates, and the like. These may be used alone or in combination of two or more. The compound (B) is preferably at least one selected from the group consisting of cyclic esters and acid anhydrides, and more preferably at least one selected from the group consisting of ε-caprolactone and phthalic anhydride. The number of ester bonds in one molecule of the compound (B) is not particularly limited as long as it is one or more, but is preferably from 1 to 4, more preferably from 1 to 3, and particularly preferably 1.

[0049] --Cyclic ester-- The cyclic ester is not particularly limited, and examples thereof include cyclic ester compounds having 3 to 9 carbon atoms, so-called lactones. There are no particular restrictions on the cyclic ester compound. For example, β-propiolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, methyl-ε-caprolactone, α-methyl-β-propiolactone, β-methyl-β-propiolactone, methoxy-ε-caprolactone, methoxy-ε-caprolactone, ethoxy-ε-caprolactone, glycolide, etc. may be mentioned. These may be used alone or in combination of two or more. Among these, ε-caprolactone, δ-valerolactone, γ-butyrolactone are preferable, and ε-caprolactone is more preferable.

[0050] -- Acid anhydride -- There are no particular restrictions on the acid anhydride. For example, polycarboxylic acid anhydrides may be mentioned. Among these, dicarboxylic acid anhydrides are preferable. There are no particular restrictions on the dicarboxylic acid anhydride. For example, aliphatic dicarboxylic acid anhydrides such as maleic anhydride, succinic anhydride, dodecenyl succinic anhydride, octadecenyl succinic anhydride; aromatic dicarboxylic acid anhydrides such as phthalic anhydride, hydroxyphthalic anhydride; alicyclic dicarboxylic acid anhydrides such as hexahydrophthalic anhydride, tetrahydrophthalic anhydride, 3-methyl-hexahydrophthalic anhydride, 4-methyl-hexahydrophthalic anhydride, 3-methyl-1,2,3,6-tetrahydrophthalic anhydride, 4-methyl-1,2,3,6-tetrahydrophthalic anhydride, etc. may be mentioned. These may be used alone or in combination of two or more. Among these, maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride are preferable, and phthalic anhydride, tetrahydrophthalic anhydride are more preferable.

[0051] -- Cyclic carbonate -- There are no particular restrictions on the cyclic carbonate. For example, ethylene carbonate, propylene carbonate, trimethylene carbonate and its substituents, etc. may be mentioned.

[0052] The addition amount of compound (B) is not particularly limited, but from the viewpoint of ensuring soil degradability, 5 to 90 parts by mass, more preferably 15 to 85 parts by mass, and even more preferably 25 to 80 parts by mass are preferable with respect to 100 parts by mass of the polyester ether polyol of the present invention.

[0053] -Mass ratio of alkylene oxide (A) and compound (B)- The mass ratio of alkylene oxide (A) and compound (B) is not particularly limited, but is preferably 35:65 to 99:1, more preferably 35:65 to 80:20, and particularly preferably 35:65 to 60:40.

[0054] (Other additives) Additives selected from hindered phenol-based or hindered amine-based antioxidants, benzotriazole-based non-ferrous corrosion inhibitors, triazole-based or benzophenone-based ultraviolet absorbers, and boron compound-based reducing agents can be added to the polyester ether polyol in order to prevent deterioration during long-term storage until subsequent use.

[0055] In addition, for pH adjustment, mineral acids such as phosphoric acid, phosphorous acid, hypophosphorous acid, pyrophosphoric acid, hydrochloric acid, sulfuric acid, sulfurous acid; organic acids such as formic acid, oxalic acid, succinic acid, acetic acid, maleic acid, benzoic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid; alkali metal hydroxides or alkaline earth metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, cesium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide; alkali metal carbonates or alkaline earth metal carbonates such as lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, magnesium carbonate, calcium carbonate, barium carbonate; bicarbonates of alkali metals or alkaline earth metal bicarbonates such as lithium hydrogen carbonate, potassium hydrogen carbonate, sodium hydrogen carbonate, cesium hydrogen carbonate; phosphates such as dilithium phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, lithium hydrogen phosphate, sodium hydrogen phosphate, potassium hydrogen phosphate, sodium acid pyrophosphate; hydrogen sulfates such as lithium hydrogen sulfate, sodium hydrogen sulfate, potassium hydrogen sulfate; fatty amines such as ethylenediamine, diethylenetriamine, hexamethylenediamine; aromatic amines such as tolylenediamine, diphenylmethanediamine; organic alkaline compounds such as alkanolamine; a compound selected from these can be added.

[0056] (Method for producing polyester ether polyol) Hereinafter, a method for producing a polyester ether polyol using an initiator compound, an alkylene oxide, and a compound having an oxygen-containing heterocyclic structure as raw materials will be described. A preferred method for producing a polyester ether polyol is to add a part of an alkylene oxide (hereinafter sometimes referred to as the alkylene oxide for the initial step) to be copolymerized with the initiator compound to a reaction solution containing an initiator compound, a DMC catalyst, and a compound having an oxygen-containing heterocyclic structure. (Hereinafter, sometimes referred to as the alkylene oxide for the initial step.) is preferably supplied and reacted in an amount of 5 to 20 parts by mass with respect to 100 parts by mass of the initiator compound contained in the reaction solution in an initial step (a), and after the initial step (a), an alkylene oxide is additionally supplied and copolymerized. It is a method having a polymerization step (b) for reacting. The organic solvent may be introduced at any step of the production process of the polyester ether polyol. Optionally, the organic solvent may be introduced into the reaction vessel before the initial step and dehydrated by performing vacuum degassing. This method is preferably carried out batchwise, but a continuous method may also be used. Specifically, it can be implemented as follows.

[0057] As the mixing means in the initial step (a) of the method for producing a polyester ether polyol, there is no particular limitation as long as it can sufficiently mix the initiator compound, the DMC catalyst, the compound having an oxygen-containing heterocyclic structure, and (including components added as necessary). As the mixing means, usually, a stirring means is used. As the stirring power of the stirring means, it is preferably 4 to 500 kW / m 3 , more preferably 8 to 500 kW / m 3 , particularly preferably 12 to 500 kW / m 3 is. Here, the stirring power is a value calculated from known values, and this value is the required power per unit liquid volume of the content, calculated from the volume and viscosity of the content in the pressure-resistant reaction vessel, the shape of the reaction vessel, and the shape and rotation speed of the stirring blade. In the present invention, the above reaction solution corresponds to the content in the pressure-resistant reaction vessel.

[0058] As stirring means in the initial step (a) of the method for producing a polyester ether polyol, specifically, stirring by a stirring blade, bubbling with an inert gas such as nitrogen gas, electromagnetic waves, ultrasonic waves, etc. can be mentioned, but stirring by a stirring blade is preferred. Preferred examples of the stirring blade include the stirring blades described in JP-A-2003-342361. A particularly large stirring blade is preferred, and large stirring blades such as FULLZONE (registered trademark) blades manufactured by Kobe Steel Pan-Tech Co., Ltd. and MAXBLEND (registered trademark) blades manufactured by Sumitomo Heavy Industries, Ltd. can be used. Also, paddle blades, pitched paddle blades, turbine blades, propeller blades, etc. can be used. At that time, the radius of the stirring blade with respect to the inner diameter (inner radius) of the pressure-resistant reaction vessel is preferably 20 to 99%, more preferably 30 to 90%, and particularly preferably 40 to 80%.

[0059] The shape and material of the pressure-resistant reaction vessel used in the initial step (a) of the method for producing a polyester ether polyol are not particularly limited, but a heat-resistant glass or metal container is preferred as the material.

[0060] As a means for supplying an alkylene oxide into the reaction vessel, an alkylene oxide supply means for discharging the alkylene oxide at two or more positions in the liquid may be provided.

[0061] Next, preferably, the inside of the pressure-resistant reaction vessel is purged with nitrogen. Thereby, oxygen in the reaction solution is removed. The amount of oxygen in the reaction solution is preferably 1% by mass or less based on the amount of nitrogen. The pressure inside the pressure-resistant reaction vessel in the initial step (a) of the method for producing a polyester ether polyol is preferably 1.020 MPaA or less, more preferably 1.015 MPaA or less, and particularly preferably 1.010 MPaA or less in absolute pressure. When the pressure inside the pressure-resistant reaction vessel in the initial step (a) of the method for producing a polyester ether polyol exceeds 1.020 MPaA in absolute pressure, the pressure increase due to the decrease in the space volume inside the pressure-resistant reaction vessel accompanying the polymerization becomes intense, which is not preferable. Note that exhausting the inside of the pressure-resistant reaction vessel does not have an effect of improving the activity of the catalyst, but may be performed if necessary in the process when the moisture content of the initiator compound is too high.

[0062] Next, while stirring the reaction solution, it is heated to raise the temperature. After that, while the temperature of the reaction solution is at a predetermined initial temperature, an alkylene oxide for the initial step is supplied and reacted. The initial temperature in this specification refers to the temperature of the reaction solution at the start of the supply of the alkylene oxide for the initial step. The initial temperature of the reaction solution is 120 to 165°C, preferably 125 to 150°C, more preferably 130 to 140°C. When the initial temperature is equal to or higher than the lower limit value of the above range, the catalytic activity is significantly improved. When it is equal to or lower than the upper limit value of the above range, there is no concern about thermal decomposition of the components contained in the reaction solution itself.

[0063] Specifically, it is preferable to raise the temperature of the reaction solution to the initial temperature while stirring, and start the supply of the alkylene oxide while the temperature of the reaction solution is maintained. For example, when the reaction solution reaches a predetermined initial temperature, stop heating, and start the supply of the alkylene oxide before the temperature of the reaction solution begins to drop. The time from stopping heating to starting the supply of the alkylene oxide is not particularly limited, but from the viewpoint of efficiency, it is preferably within 1 hour. The temperature-raising time for raising the temperature of the reaction solution to a predetermined temperature is preferably 10 minutes to 24 hours, more preferably 15 minutes to 2 hours. When the temperature-raising time is equal to or higher than the lower limit value of the above range, the reaction solution can be heated uniformly, and when it is equal to or lower than the upper limit value of the above range, the efficiency is good in terms of time.

[0064] The alkylene oxide for the initial step is an alkylene oxide polymerized with an initiator compound in the production of a polyester ether polyol. If the supply amount of the alkylene oxide for the initial step is too small, the activation of the DMC catalyst will be insufficient, and if it is too large, a runaway reaction will occur. Therefore, the supply amount of the alkylene oxide for the initial step is preferably 5 to 20 parts by mass, more preferably 8 to 15 parts by mass, and particularly preferably 10 to 12 parts by mass with respect to 100 parts by mass of the initiator compound contained in the reaction solution.

[0065] The supply of alkylene oxide for the initial step is carried out with the pressure-resistant reaction vessel sealed. When alkylene oxide is supplied to the reaction solution, immediately thereafter, the internal pressure of the pressure-resistant reaction vessel increases due to the vaporization of unreacted alkylene oxide. Next, when the DMC catalyst is initially activated, a reaction occurs between the alkylene oxide and the initiator compound, and the internal pressure of the pressure-resistant reaction vessel begins to decrease. At the same time, the temperature of the reaction solution rises due to the heat of reaction. When the total amount of the supplied alkylene oxide has finished reacting, the internal pressure of the pressure-resistant reaction vessel decreases to about the same level as before the supply, and the temperature rise of the reaction solution due to the heat of reaction disappears. Depending on the amount of the organic solvent, there may be a case where almost no temperature rise of the reaction solution due to the heat of reaction is observed, and an increase in the internal pressure is observed. The initial step (a) in this specification refers to the step from the start of the supply of alkylene oxide for the initial step to the end of the reaction of the alkylene oxide. The end of the reaction of alkylene oxide for the initial step can be confirmed by the decrease in the internal pressure of the pressure-resistant reaction vessel. That is, the end of the initial step (a) means the time when the internal pressure of the pressure-resistant reaction vessel has decreased to about the same level as before the supply of alkylene oxide. The initial step is preferably 10 minutes to 24 hours, more preferably 15 minutes to 3 hours. When it is above the lower limit value of the above range, the DMC catalyst can be activated, and when it is below the upper limit value of the above range, the efficiency is good in terms of time.

[0066] After the initial step is completed, alkylene oxide is newly supplied to the reaction system, the temperature of the reaction solution is adjusted to a predetermined polymerization temperature, and a copolymerization reaction is carried out while stirring to obtain the target polyester ether polyol. As the heat-resistant reaction vessel used in the polymerization step (b) of the production method of the present invention, it is preferable to use a pressure-resistant autoclave vessel. However, when the boiling points of alkylene oxide, a compound having an oxygen-containing heterocyclic structure, an organic solvent, etc. are high, it may not be necessary to have high pressure resistance. The material is not particularly limited. Note that the reaction vessel used in the above initial step (a) can be used as it is.

[0067] In the polymerization step (b) of the method for producing a polyester ether polyol, in the presence of a DMC catalyst, during the reaction of the product of the initial step (a) (a compound obtained by reacting an alkylene oxide and a compound having an oxygen-containing heterocyclic structure with an initiator compound) with an alkylene oxide and an optional compound having an oxygen-containing heterocyclic structure, the reaction solution is preferably stirred with a stirring power of 4 to 500 kW / m 3 , more preferably 8 to 500 kW / m 3 , particularly preferably 12 to 500 kW / m 3 . Regarding the stirring blade, a propeller blade, a paddle blade, a max blend blade, or a disk turbine can be used, and a large blade is preferred for uniformly mixing the inside of the reaction vessel. As others, a disperser, a homomixer, a colloid mill, a Nauta mixer, etc. used for emulsification and dispersion can also be used. Further, mixing by ultrasonic waves may be used without using a stirring blade. These stirring methods may be used in combination. When using a stirring method using a general stirring blade, it is preferable to make the rotation speed of the stirring blade as fast as possible within a range where a large amount of gas in the gas phase part of the reactor is not taken into the reaction solution and the stirring efficiency does not decrease.

[0068] As the polymerization method in the polymerization step (b) of the method for producing a polyester ether polyol, there are a batch method and a continuous method, and from the viewpoint of easy control for obtaining a desired molecular weight, the batch method is preferred. The continuous method is a method of simultaneously adding a mixture containing an alkylene oxide, the product of the initial step (a), and a DMC catalyst and extracting the polyester ether polyol, which is the product of the polymerization step (b).

[0069] When reacting the polyester ether polyol in the polymerization step (b), the temperature of the reaction solution (polymerization temperature) is preferably 125 to 180 °C, more preferably 125 to 160 °C. When the polymerization temperature is at least the lower limit of the above range, a good reaction rate can be obtained, and the residual amount of unreacted substances in the final product can be reduced. Also, when it is at most the upper limit of the above range, the high activity of the DMC catalyst is well maintained, and the molecular weight distribution can be narrowed. After the reaction of the alkylene oxide in the polymerization step (b) is completed, it is preferable to cool the reaction solution and purify the reaction product.

[0070] Since the supply rate of the alkylene oxide in the polymerization step (b) can narrow the molecular weight distribution of the resulting polymer, it is preferably made as slow as possible. However, since the production efficiency decreases, it is preferable to determine this by comparing them. As a specific supply rate, it is preferably 1 to 200% by mass / hour with respect to the total mass of the polyester ether polyol planned as the final product. Note that the supply rate during the copolymerization reaction may be sequentially changed.

[0071] The reaction time in the polymerization step (b) of the method for producing a polyester ether polyol is preferably 10 minutes to 40 hours, more preferably 30 minutes to 24 hours. When the reaction time is at least the lower limit of the above range, the reaction can be controlled, but when it is at most the upper limit of the above range, it is preferable in terms of efficiency.

[0072] The pressure in the pressure-resistant reaction vessel in the polymerization step (b) of the method for producing a polyester ether polyol is preferably 2 MPaA or less, more preferably 1.8 MPaA or less in absolute pressure in terms of ease of operation and equipment. A polyester ether polyol obtained by performing polymerization using the DMC catalyst as described above, and further copolymerizing an alkylene oxide and a compound having an oxygen-containing heterocyclic structure using a polymerization catalyst other than the DMC catalyst may be used as the final polyester ether polyol. The copolymerization reaction can be carried out by a known method using, for example, an alkali metal catalyst such as potassium hydroxide as the polymerization catalyst.

[0073] In addition, from the obtained polyester ether polyol, if necessary, a DMC catalyst removal treatment and a DMC catalyst deactivation treatment may be performed. Examples of the method include an adsorption method using an adsorbent selected from synthetic silicates (such as magnesium silicate and aluminum silicate), ion exchange resins, activated clay, etc., a neutralization method using amines, alkali metal hydroxides, phosphoric acid, lactic acid, succinic acid, adipic acid, acetic acid and other organic acids and their salts, or inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, etc., and a method of using a combination of the neutralization method and the adsorption method. When the primary hydroxylation using the alkali metal catalyst is performed, the alkali metal catalyst can be deactivated and removed in the same manner.

[0074] To the polyethers thus obtained, a stabilizer may be added as necessary to prevent deterioration during long-term storage. Examples of the stabilizer include 2,6-di-t-butyl-4-cresol (BHT); hindered phenolic antioxidants such as Irganox 1010 (product name of BASF, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]), Irganox 1076 (product name of BASF, stearyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate), Irganox 1135 (product name of BASF, octyl 3,5-di-t-butyl-4-hydroxy-hydrocinnamate); hindered amine antioxidants such as Tinuvin 765 (product name of BASF, sebacic acid bis(1,2,2,6,6-pentamethyl-4-piperidyl)), Nonflex DCD (product name of Seiko Chemical Co., Ltd., 4,4'-bis(α,α-dimethylbenzyl)diphenylamine); benzotriazole-based non-ferrous corrosion inhibitors; triazole-based and benzophenone-based ultraviolet absorbers; boron compound-based reducing agents; etc. Additives selected from these can be added. When adding an antioxidant, the addition amount is preferably 50 to 5,000 mass ppm, more preferably 500 to 4,000 mass ppm, based on the obtained polyether polyol.

[0075] As a method for supplying an alkylene oxide and a compound having an oxygen-containing heterocyclic structure, for example, a method of adding the compound having an oxygen-containing heterocyclic structure all at once, a method of adding the compound having an oxygen-containing heterocyclic structure in portions, a method of adding a mixture of an alkylene oxide and a compound having an oxygen-containing heterocyclic structure in a pipe (pipe mixing method), etc. can be mentioned.

[0076] In the method of adding the compound having an oxygen-containing heterocyclic structure all at once or in portions, an initiator compound and a compound having an oxygen-containing heterocyclic structure are charged into the reaction vessel, and an alkylene oxide is introduced through an alkylene oxide supply means provided with a flow rate control valve or the like in advance. In the method of adding all at once, the compound having an oxygen-containing heterocyclic structure is charged in the total amount at once, and the alkylene oxide is introduced. In the method of adding in portions, the compound having an oxygen-containing heterocyclic structure is charged multiple times, and the alkylene oxide is introduced multiple times.

[0077] In the pipe mixing method, a pipe for supplying an alkylene oxide and a compound having an oxygen-containing heterocyclic structure provided with a flow rate control valve or the like in advance toward the reactor is provided, and the alkylene oxide and the compound having an oxygen-containing heterocyclic structure are introduced into the reactor in a state where their flow rates are each controlled. The alkylene oxide and the compound having an oxygen-containing heterocyclic structure may be independently introduced into the reactor, or the two liquids may be collided and mixed on the way. In order to improve the miscibility, they may be mixed through a static mixer or a dynamic mixer.

[0078] In the method for producing a polyester ether polyol, an organic solvent may or may not be used. The organic solvent that can be used in the method for producing a polyester ether polyol is not particularly limited, and examples include hexane, octane, 1,4-dioxane, carbon tetrachloride, toluene, diethyl ether, ethyl acetate, acetic acid, tetrahydrofuran, dichloromethane, cyclohexanol, 1-butanol, etc. These may be used alone or in combination of two or more. Among these, hexane, toluene, and tetrahydrofuran are preferred as the organic solvent that does not react with the initiator compound, alkylene oxide, and the compound having an oxygen-containing heterocyclic structure, in terms of suitability, odor, environmental load, and boiling point.

[0079] <<Polyisocyanate>> Polyisocyanate is an organic compound having two or more isocyanate groups in one molecule. The number of isocyanate groups in one molecule is preferably 2 to 4. There is no particular limitation on the polyisocyanate. For example, linear or branched aliphatic diisocyanate compounds such as tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, dodecamethylene diisocyanate, lysine diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate; alicyclic diisocyanate compounds such as norbornane diisocyanate (NBDI), isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, dicyclohexylmethane diisocyanate (H 12 MDI); Aromatic polyisocyanate compounds such as tolylene diisocyanate (TDI), 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate, xylylene diisocyanate, α,α,α',α'-tetramethylxylylene diisocyanate, 4,4'-dibenzyl diisocyanate, tolidine diisocyanate, 1,5-naphthalene diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate; Isocyanurate-modified products of the above-mentioned diisocyanate compounds; biuret-modified products of the above-mentioned diisocyanate compounds; allophanate-modified products of the above-mentioned diisocyanate compounds; carbodiimide-modified products of the above-mentioned diisocyanate compounds; trifunctional or higher isocyanate group-terminated urethane prepolymers (adduct-modified products) obtained by reacting the above-mentioned diisocyanate compounds with a polyol having three or more hydroxyl groups in one molecule; water-dispersible polyisocyanate compounds such as water-dispersed isocyanates and blocked isocyanates; polyisocyanate compounds having three or more isocyanate groups in one molecule such as triphenylmethane triisocyanate; etc. These may be used alone or in combination of two or more. Among these, HDI and MDI are preferred from the viewpoints of cost, availability, etc.

[0080] The content of isocyanate groups in the polyisocyanate is preferably 20 to 70% by mass, more preferably 25 to 60% by mass, and particularly preferably 30 to 55% by mass from the viewpoint of obtaining good reactivity with the polyol.

[0081] The molecular weight of the polyisocyanate compound is not particularly limited, but is preferably 120 to 400, more preferably 130 to 390, and particularly preferably 140 to 380. When the molecular weight of the polyisocyanate compound is within the above range, good reactivity with the polyol can be obtained.

[0082] <Other Components> There are no particular restrictions on other components in the coating material other than the urethane resin. For example, polyamide, polypropylene, polyethylene, polyethylene terephthalate, polylactic acid, polycaprolactone, polybutylene succinate, polybutylene adipate / terephthalate, polyglycolic acid, cellulose acetate, etc. may be mentioned. These may be used alone or in combination of two or more. Among these, from the viewpoint of biodegradability, polybutylene adipate / terephthalate is preferred.

[0083] [Manufacturing Method of Coating Material] The manufacturing method of the coating material of the present invention includes reacting the above-mentioned polyol with the above-mentioned polyisocyanate to obtain a urethane resin. More specifically, an isocyanate-terminated prepolymer may be obtained by reacting the above-mentioned polyol with the above-mentioned polyisocyanate, and then the obtained isocyanate-terminated prepolymer may be reacted with water (moisture in the air) to obtain a urethane resin. Alternatively, a urethane resin may be obtained by reacting the above-mentioned polyol with the above-mentioned polyisocyanate and other optional components such as a crosslinking agent.

[0084] The mass ratio of polyol to polyisocyanate (polyol / polyisocyanate) is not particularly limited, but from the viewpoint of forming sufficient crosslinking, it is preferably 1 to 20, more preferably 1 to 12, and particularly preferably 1 to 5.

[0085] The coating material of the present invention can be suitably used as a coating material for coated granular fertilizers, coated granular pesticides, coated seeds, etc.

[0086] [Coated Granular Fertilizer] The coated granular fertilizer of the present invention includes a granular fertilizer coated with the coating material of the present invention. The components of the granular fertilizer are not particularly limited. For example, they are components containing various elements such as nitrogen, phosphorus, potassium, silicon, magnesium, calcium, manganese, boron, iron, etc., which are applied to the soil to provide nutrients in plant cultivation. For example, nitrogenous fertilizer components such as urea, ammonium nitrate, ammonium magnesium nitrate, ammonium chloride, ammonium sulfate, ammonium phosphate, sodium nitrate, calcium nitrate, potassium nitrate, calcium cyanamide, formaldehyde-treated urea (UF), acetaldehyde-treated urea (CDU), isobutylaldehyde-treated urea (IBDU), guanyl urea (GU), etc.; phosphatic fertilizer components such as superphosphate of lime, triple superphosphate, fused phosphorus, humic acid phosphorus, calcined phosphorus, double calcined phosphorus, magnesium superphosphate, ammonium polyphosphate, potassium metaphosphate, calcium metaphosphate, magnesium phosphate, ammonium sulfate phosphate, ammonium phosphate nitrate potassium, ammonium chloride phosphate, etc.; potassic fertilizer components such as potassium chloride, potassium sulfate, potassium sodium sulfate, potassium magnesium sulfate, potassium bicarbonate, potassium phosphate, etc.; siliceous fertilizer components such as calcium silicate, etc.; magnesiumous fertilizer components such as magnesium sulfate, magnesium chloride, etc.; calcareous fertilizer components such as quicklime, slaked lime, calcium carbonate, etc.; manganous fertilizer components such as manganese sulfate, magnesium manganese sulfate, manganese ore, etc.; boronous fertilizer components such as boric acid, borate, etc.; iron-containing fertilizer components such as steel slag, etc. These may be used alone or in combination of two or more.

[0087] [Coated granular pesticide] The coated granular pesticide of the present invention includes a granular pesticide coated with the coating material of the present invention. The components of the granular pesticide are not particularly limited. For example, they include insecticide components, fungicide components, and herbicide components. These may be used alone or in combination of two or more.

[0088] [Coated seed] The coated seed of the present invention includes a seed coated with the coating material of the present invention. There are no particular restrictions on the seeds. For example, from the perspective of facilitating sowing of irregularly shaped seeds and reducing sowing labor, carrot seeds, lettuce seeds, etc. are preferably mentioned. These may be used alone or in combination of two or more.

[0089] There are no particular restrictions on the method of forming the above-mentioned urethane resin film around the coating targets such as granular fertilizers, granular pesticides, and seeds. For example, (1) a method of spraying a separately prepared solution or emulsion of urethane resin or prepolymer around the coating target and then removing the solvent to form a film of urethane resin or prepolymer; (2) a method of adding a polyol and a polyisocyanate to the coating target simultaneously or sequentially and preparing a urethane resin on the surface of the coating target to form a film; (3) a method of previously containing one of a polyol and a polyisocyanate in the coating target and then reacting the other of the polyol and the polyisocyanate with the coating target to form a urethane resin film on the surface of the coating target; (4) a method of dispersing or emulsifying the coating target in a separately prepared solution or emulsion of urethane resin or prepolymer and producing fine particles having a matrix-like film by a spray drying method or the like.

[0090] If the film is homogeneous, even if the amount of the resin used for the film is reduced, the elution suppression performance can be obtained. Therefore, the urethane resin film is preferably produced by reacting a polyisocyanate and a polyol on the surface of the coating target under solvent-free conditions. When the polyol and the polyisocyanate have appropriate fluidity at the temperature during the production of the urethane resin, the urethane resin can form a film without using a solvent during resin molding, and thus it can be preferably used as a film of a coated granular material containing a pesticide or a fertilizer.

[0091] The manufacturing method of the coated granular material coated with the coating material of the present invention will be described in more detail. Particles to be coated such as granular fertilizers, granular pesticides, seeds, etc. are put into a fluidized state or a rolling state in a device such as a fluidized jet device, a rotary pan, or a rotary drum. The size of the particles is not particularly limited, but is usually 0.1 to 15 mm, and the shape is preferably spherical, but other shapes such as cylindrical may also be acceptable. The particles in the fluidized or rolling state are heated as necessary. Next, a mixture of a polyol, a polyisocyanate, and a catalyst added as necessary is added to the particles in the fluidized or rolling state. As the addition method, either a method of quickly adding after mixing each component or a method of adding each component separately may be used. Thereafter, while maintaining the fluidized or rolling state, the reaction between the hydroxyl group of the polyol and the isocyanate group of the polyisocyanate is allowed to proceed to form a urethane resin film on the surface of the particles. It is preferable to adjust the amount of the urethane resin added so that the thickness of the film formed in this single operation is usually 1 to 20 μm. Further, when the thickness of the film is required, the thickness of the urethane resin film can be increased by repeating the above operation. In the coated granular material coated with the coating material of the present invention, the thickness of the urethane resin film is not particularly limited, but is usually 1 to 1000 μm, preferably 8 to 400 μm, and in terms of mass, it is usually 1 to 20% by mass, preferably 3 to 16% by mass, based on the coated granular material coated with the coating material of the present invention. The coated granular material coated with the coating material of the present invention usually has a particle size in the range of 1 to 15 mm.

Examples

[0092] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0093] [Evaluation Method and Measurement Method] <Number average molecular weight (Mn) and mass average molecular weight (Mw)> The number average molecular weight (Mn) and weight average molecular weight (Mw) of polymers such as polyester ether polyol are polystyrene equivalent molecular weights obtained by measuring with gel permeation chromatography (GPC) under the following conditions using a calibration curve prepared with a standard polystyrene sample of known molecular weight. The measurement results of the number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) are shown in Table 1. <<GPC Measurement Conditions>> Model used: HLC-8320GPC (manufactured by Tosoh Corporation) Columns used: 2 x TSG gel SuperHZ 4000, 2 x 2500 (manufactured by Tosoh Corporation) Column temperature: 40 °C Detector: RI Solvent: Tetrahydrofuran Flow rate: 0.35 mL / min Sample concentration: 0.5% Injection volume: 20 μL Standard sample for calibration curve preparation: Polystyrene (manufactured by Polymer Laboratories; 〔EasiCal〕PS-2 〔Polystyrene Standard〕)

[0094] <EO content (mass%)> The EO content (mass%) was calculated by the following formula. The results are shown in Table 1. EO content (mass%) = A1 / B × 100 A1: Sum of the charged mass (g) of PEG600, which is the initiator compound, and the charged mass (g) of EO B: Sum of the charged masses (g) of all raw materials used in the production

[0095] <PO content (mass%)> The PO content (mass%) was calculated by the following formula. The results are shown in Table 1. PO content (mass%) = A2 / B × 100 A2: Sum of the charged mass (g) of EXCENOL430, which is the initiator compound, and the charged mass (g) of PO B: Sum of the charged masses (g) of all raw materials used in the production

[0096] <Ester group concentration (mass%)> The ester group concentration (mass %) was calculated by the following formula. The measurement results are shown in Table 1. Ester group concentration (mass %) = 44 × C × 100 / (D × E + 1 × F) C: The number of ester groups contained in the charged copolymer composition For example, in the copolymerization of alkylene oxide and epsilon-caprolactone, the number of ester groups (C) contained in the charged copolymer composition is 1, and in the copolymerization of alkylene oxide and phthalic anhydride, the number of ester groups (C) contained in the charged copolymer composition is 2. D: The molar number of charged alkylene oxide converted per mole of charged cyclic ester compound E: The molecular weight of the charged alkylene oxide F: The molecular weight of the charged cyclic ester compound Note that "44" is the ester group molecular weight.

[0097] <Hydroxyl value> Analysis was carried out in accordance with Method B (phthalation method) described in JIS K 1557-1:2007. The measurement results are shown in Table 1.

[0098] <EO content in resin (mass%)> The EO content in the resin (mass %) was calculated by the following formula. The measurement results are shown in Table 2. EO content in resin (mass %) = EO content (mass %) × G / (G + H) G: The mass of polyol charged during resin production (g) H: The mass of isocyanate charged during resin production (g) Note that in this specification, the EO content (mass %) is calculated from the charged amount during the production of the urethane resin as described above. However, the urethane resin can also be dissolved in a deuterated solvent and 1 analyzed using H-NMR. When the urethane resin is insoluble in the deuterated solvent, the urethane resin and an aqueous solution of sodium hydroxide or potassium hydroxide are added to a pressure-resistant autoclave and hydrolyzed overnight in an oven set at 80 - 110 °C, and then the alkali hydrolyzate of the urethane resin is dissolved in the deuterated solvent 1By analyzing using \(^1H\)-NMR, the EO content (mass %) can also be measured from the urethane resin.

[0099] <PO content (mass %) in the resin> The PO content (mass %) in the resin was calculated by the following formula. The measurement results are shown in Table 2. PO content (mass %) in the resin = PO content (mass %) × G / (G + H) G: Mass of polyol charged during resin production (g) H: Mass of isocyanate charged during resin production (g) In this specification, the PO content (mass %) is calculated from the charged amount during the production of the urethane resin as described above. However, the urethane resin is dissolved in a deuterated solvent, 1 and it can also be analyzed using \(^1H\)-NMR. When the urethane resin is insoluble in the deuterated solvent, the urethane resin and an aqueous solution of sodium hydroxide or potassium hydroxide are added to a pressure-resistant autoclave, hydrolyzed overnight in an oven set at 80 - 110 °C, and then the alkali hydrolyzate of the urethane resin is dissolved in a deuterated solvent 1 By analyzing using \(^1H\)-NMR, the PO content (mass %) can also be measured from the urethane resin.

[0100] <Ester group concentration (mass %) in the resin> The ester group concentration in the resin was calculated by the following formula. The measurement results are shown in Table 2. Ester group concentration (mass %) in the resin = Ester group concentration (mass %) × G / (G + H) G: Mass of polyol charged during resin production (g) H: Mass of isocyanate charged during resin production (g) In this specification, the ester group concentration (mass %) is calculated from the charged amount during the production of the urethane resin as described above. However, the urethane resin is dissolved in a deuterated solvent, 1It can also be analyzed using H-NMR. When the urethane resin is insoluble in a deuterated solvent, the urethane resin and an aqueous solution of sodium hydroxide or potassium hydroxide are added to a pressure-resistant autoclave and hydrolyzed overnight in an oven set at 80 to 110 °C. Then, the alkali hydrolyzate of the urethane resin is dissolved in a deuterated solvent. 1 By analyzing using H-NMR, the ester group concentration (mass %) can also be measured from the urethane resin.

[0101] <NCO content measurement> Analysis was carried out in accordance with JIS K1603-1:2007 Method A (toluene / dibutylamine·hydrochloric acid method). The measurement results are shown in Table 2. Note that the NCO content measurement is a method used to confirm the progress of the prepolymerization reaction. When synthesizing a prepolymer, if the isocyanate index is determined, the theoretical NCO% can be calculated from the amount of polyol and polyisocyanate charged. By measuring the NCO content using this analytical method and confirming the difference from the theoretical NCO%, it becomes possible to judge the progress of the reaction (whether an additional reaction is required, whether it is possible to proceed to the next step, etc.).

[0102] <Test film preparation method> For the test film, after placing an appropriate amount of the NCO-terminated prepolymer obtained in Examples 1 to 4 below on a release PET film, it was molded using an applicator (Yoshimitsu Seiki Co., Ltd. Baker applicator YBA-4 standard type) set to a film thickness of 500 μm, and then left standing under conditions of 23 °C and 50% humidity to be moisture-cured.

[0103] <Soil degradability test> After cutting the prepared test film into 2 cm × 2 cm pieces, they were charged so as to be completely buried in the soil (horticultural culture soil: produced by Togawa Heiwanoen) spread in a planter. After 8 weeks under conditions of 25 °C, they were taken out, and the change in the appearance of the film was visually confirmed and evaluated according to the following evaluation criteria. The evaluation results are shown in Table 2. <<Evaluation criteria>> A: Severely decomposed B: Decomposed C: Slightly decomposed D: Without decomposition

[0104] <Hydrolysis test> After cutting out the prepared test film to a mass of 1 g, it was charged into a sealable glass container filled with pure water so that the film was completely immersed, and then sealed. After 8 weeks under the condition of 80 °C, the glass container was taken out, and the change in the appearance of the film was visually confirmed and evaluated according to the following evaluation criteria. The evaluation results are shown in Table 2. <<Evaluation criteria>> A: Decomposition B: Slight decomposition C: Without decomposition

[0105] <Preparation of DMC catalyst A> The DMC catalyst obtained by the method described in Example 3 of JP-A-2003-190808 was used. That is, to the reaction solution obtained by reacting zinc chloride with K3[Co(CN)6], a mixture of 80 g of tert-butyl alcohol, 1 g of polyoxypropylene glycol (also referred to as "PPG1") having a number average molecular weight of 1,500, a hydroxyl value of 75 mg KOH / g, and 2 hydroxyl groups, and 80 g of water was added, and the temperature was raised to 60 °C. After stirring for 1 hour, a filtration operation (first filtration) was performed to obtain a cake containing the composite metal cyanide complex catalyst organic phase. Next, a mixture of 40 g of tert-butyl alcohol, 1 g of "PPG1", and 70 g of water was added to the cake containing the composite metal cyanide complex catalyst organic phase, stirred for 30 minutes, and then a filtration operation (second filtration) was performed. To the cake containing the composite metal cyanide complex catalyst organic phase obtained by this filtration operation, a mixture of 80 g of tert-butyl alcohol, 1 g of "PPG1", and 10 g of water was further added and stirred, and a filtration operation (third filtration) was performed. The cake containing the composite metal cyanide complex catalyst organic phase obtained by this filtration operation was dried at 80 °C until there was no change in mass, and then pulverized to obtain a powdery composite metal cyanide complex catalyst (also referred to as "DMC catalyst A").

[0106] Hereinafter, Examples 1 to 2 are examples, and Examples 3 to 4 are comparative examples. [Substances used] Details of various substances used below are shown below. · PO: Propylene oxide · Polypropylene glycol (mass average molecular weight (Mn) 420, number of functional groups (hydroxyl groups) 3, EXCENOL 430 manufactured by AGC Inc.) · Phthalic anhydride (manufactured by Air Water Inc.) · Irganox 1076 (manufactured by BASF Japan Ltd.) · Neostan U-100 (manufactured by Nitto Kasei Co., Ltd.) · 85 mass% phosphoric acid (manufactured by Junsei Chemical Co., Ltd.) · HDI: Hexamethylene diisocyanate (manufactured by Tosoh Corporation) · Commercially available polypropylene glycol (mass average molecular weight (Mn) 2,000, EXCENOL 2020 manufactured by AGC Inc.) · Commercially available polycaprolactone diol (mass average molecular weight (Mn) 2,000, Placcel 220N manufactured by Daicel Chemical Industries, Ltd.)

[0107] (Production Example 1) Synthesis of PO / phthalic anhydride copolymer of polypropylene glycol with phthalic anhydride charged all at once To a 10 L reactor equipped with a stirrer, stirring blades, a heating jacket, a cooling coil, a nitrogen introduction pipe, and a pressure reduction pipe, 1,813 g of polypropylene glycol was added. Then, after adding 0.9 g of the above DMC catalyst A thereto and replacing with nitrogen gas, the temperature was raised to 130°C, and under a reduced pressure of -0.1 MPaG, a mixing treatment was performed for 1 hour under stirring conditions of 200 rpm while maintaining the temperature in the tank at 130°C, and the pressure in the reactor was set to 0.01 MPaG. After the above pretreatment was completed, 181 g of PO was fed at 130°C for initial activation. After confirming that initial activation occurred due to a decrease in internal pressure, the inside of the reactor was pressurized with nitrogen gas to 0.1 MPaG, the temperature was lowered to 80°C, and after setting the pressure in the tank to 0 MPaG, 1,344 g of phthalic anhydride (also referred to as "PAH") was charged, the temperature was raised to 130°C, and the pressure in the reactor was set to 0.01 MPaG. PO1,162 g was fed at 130 °C for 3 hours. After aging for 1 hour at 130 °C, the reactor was depressurized to -0.1 MPaG, and it was confirmed that there was no unreacted PO and phthalic anhydride. Thereafter, 4.5 g of Irganox 1076 was added thereto as an antioxidant, and then a polyester ether polyol, which is a PO / phthalic anhydride copolymer of polypropylene glycol, was produced as a product and taken out. For the taken-out polyester ether polyol, the EO content, PO content, ester group concentration, hydroxyl value, and the number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) were calculated by GPC measurement. The results are shown in Table 1.

[0108] (Production Example 2) Synthesis of PO / phthalic anhydride copolymer of polypropylene glycol with phthalic anhydride charged all at once In Production Example 1, instead of charging 1,344 g of phthalic anhydride and feeding 1,162 g of PO at 130 °C for 3 hours, 1,612 g of phthalic anhydride was charged and 894 g of PO was fed at 130 °C for 3 hours. In the same manner as in Production Example 1, a PO / phthalic anhydride copolymer of polypropylene glycol was produced and taken out. For the taken-out polyester ether polyol, the EO content, PO content, ester group concentration, hydroxyl value, and the number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) were calculated. The results are shown in Table 1.

[0109] (Example 1) Synthesis of NCO-terminated prepolymer using the polyester ether polyol produced in Production Example 1 and HDI In a 500 mL flask equipped with a stirrer, stirring blades, a nitrogen introduction pipe, and a decompression pipe, 300 g of the polyester ether polyol (PO / phthalic anhydride copolymer of polypropylene glycol) produced in Production Example 1, 0.002 g of Neostan U-100, and 0.002 g of 85% by mass phosphoric acid were charged. After heating to 70 °C while slightly flowing nitrogen, 152.7 g of HDI was charged and reacted for 4.5 hours until the NCO content reached the theoretical value calculated from the isocyanate index, to obtain an NCO-terminated prepolymer.

[0110] (Example 2) Synthesis of an NCO-terminated prepolymer using the polyester ether polyol produced in Production Example 2 and HDI In a 500 mL flask equipped with a stirrer, stirring blades, a nitrogen introduction pipe, and a decompression pipe, 300 g of the polyester ether polyol (PO / phthalic anhydride copolymer of polypropylene glycol) produced in Production Example 2, 0.002 g of Neostan U-100, and 0.002 g of 85% by mass phosphoric acid were charged. After heating to 70 °C while slightly flowing nitrogen, 133.0 g of HDI was charged and reacted for 4.5 hours until the NCO content reached the theoretical value calculated from the isocyanate index, to obtain an NCO-terminated prepolymer.

[0111] (Example 3) Synthesis of an NCO-terminated prepolymer using a commercially available polypropylene glycol (EXCENOL 2020) and HDI In a 500 mL flask equipped with a stirrer, stirring blades, a nitrogen introduction pipe, and a decompression pipe, 300 g of EXCENOL 2020 (polypropylene glycol, mass average molecular weight (Mw) 2,000), 0.002 g of Neostan U-100, and 0.002 g of 85% by mass phosphoric acid were charged. After heating to 70 °C while slightly flowing nitrogen, 50.5 g of HDI was charged and reacted for 4.5 hours until the NCO content reached the theoretical value calculated from the isocyanate index, to obtain an NCO-terminated prepolymer.

[0112] (Example 4) Synthesis of an NCO-terminated prepolymer using a commercially available polycaprolactone diol (Placcel 220N) and HDI In a 500 mL flask equipped with a stirrer, stirring blades, a nitrogen introduction pipe, and a decompression pipe, 300 g of Placcel 220N (polycaprolactone diol, mass average molecular weight (Mw) 2,000), 0.002 g of Neostan U-100, and 0.002 g of 85 mass% phosphoric acid were charged. After heating to 70 °C while slightly flowing nitrogen, 50.5 g of HDI was charged and reacted for 4.5 hours until the NCO content reached the theoretical value calculated from the isocyanate index, obtaining an NCO-terminated prepolymer.

[0113]

Table 1

Table 2

[0114] (Evaluation Results) In Examples 1 to 2, the urethane resin obtained by molding an NCO-terminated prepolymer using a polyester ether polyol (alkylene oxide / cyclic ester copolymer of the initiator compound) and various isocyanates into a film and subjecting it to moisture curing showed high soil degradability (Soil degradability A - B). On the other hand, the urethane resin obtained by molding an NCO-terminated prepolymer using a commercially available polypropylene glycol in Example 3 and a commercially available polycaprolactone diol in Example 4 and various isocyanates into a film and subjecting it to moisture curing did not show soil degradability under the same condition evaluation (Soil degradability C - D). In Example 1, since the polyol used has an ester group (ester group concentration 29.7 mass%) and the urethane resin has a certain degree of hydrophilicity, it is presumed that a certain degree of soil degradability and hydrolysis in hot water can be obtained (Soil degradability B, Hydrolysis in hot water B). In Example 2, since the ester group concentration of the polyol used is high (ester group concentration 35.6 mass%), it is presumed that the soil degradability is high (Soil degradability A). Also, since the polyol used has an ester group (ester group concentration 35.6 mass%) and the urethane resin has a certain degree of hydrophilicity, it is presumed that a certain degree of hydrolysis in hot water can be obtained (Hydrolysis in hot water B). In Example 3, the polyol used does not have an ester group (ester group concentration: 0.0% by mass), and it is presumed that the hydrophilicity of the urethane resin is low and no hydrolysis in hot water is observed (hydrolysis in hot water C). Also, a very long time was required for soil degradation (soil degradability D). In Example 4, the polyol used has an ester group (ester group concentration: 38.5% by mass), and since the urethane resin has hydrophilicity, it is presumed that hydrolysis in hot water was shown to some extent (hydrolysis in hot water B). Also, a long time was required for soil degradation (soil degradability C). The above results suggest that the urethane resins obtained in Examples 1 to 2 are excellent in soil degradability and can be used as various coating materials.

Industrial Applicability

[0115] The coating material of the present invention can be suitably used as a coating material for coated granular fertilizers, coated granular pesticides, coated seeds, and the like.

Claims

1. A coating material containing a urethane resin having a polyol structural unit derived from a polyol and a polyisocyanate structural unit derived from a polyisocyanate, wherein the polyol contains a polyester ether polyol obtained by copolymerizing an alkylene oxide having 2 to 20 carbon atoms having an epoxy ring and a compound other than the alkylene oxide, which has an oxygen-containing heterocyclic structure and an ester bond, with a compound having at least one active hydrogen atom in one molecule in the presence of a double metal cyanide complex catalyst.

2. The coating material according to claim 1, wherein the urethane resin contains 20 to 65% by mass of a structural unit based on propylene oxide.

3. The coating material according to claim 1 or 2, wherein the ester group concentration of the urethane resin is 5 to 30% by mass.

4. The coating material according to claim 1 or 2, wherein the compound having at least one active hydrogen atom in one molecule has 1 to 12 hydroxyl groups and a mass average molecular weight of 18 to 20,000.

5. The coating material according to claim 1 or 2, wherein the mass ratio of the alkylene oxide to the compound having an oxygen-containing heterocyclic structure is 35:65 to 99:

1.

6. The coating material according to claim 1 or 2, wherein the compound having an oxygen-containing heterocyclic structure is at least one selected from the group consisting of ε-caprolactone and phthalic anhydride.

7. The coating material according to claim 1 or 2, wherein the alkylene oxide is at least one selected from the group consisting of ethylene oxide and propylene oxide.

8. The coating material according to claim 1 or 2, wherein the hydroxyl value of the polyester ether polyol is 30 to 200 mgKOH / g.

9. The coating material according to claim 1 or 2, wherein the number average molecular weight of the polyester ether polyol is 900 to 5,000.

10. The coating material according to claim 1 or 2, wherein the molecular weight distribution of the polyester ether polyol is 1.08 to 1.

50.

11. The coating material according to claim 1 or 2, wherein the isocyanate index of the urethane resin is 80 to 300.

12. A coated granular fertilizer comprising the granular fertilizer coated with the coating material according to claim 1 or 2.

13. A coated granular pesticide comprising the granular pesticide coated with the coating material according to claim 1 or 2.

14. A coated seed comprising the seed coated with the coating material according to claim 1 or 2.

15. A method for producing a coating material for producing the coating material according to claim 1 or 2, A method for producing a coating material, which comprises reacting a polyol constituting the polyol structural unit with a polyisocyanate constituting the polyisocyanate structural unit to obtain a urethane resin.

16. The method for producing a coating material according to claim 15, wherein the mass ratio of the polyol to the polyisocyanate is 1 to 20.

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