JP2003192482A - Granular fertilizer coated with biodegradable film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coated granular fertilizer which has excellent characteristics, such as a rapid intra-environmental decomposition or collapse of films after elution of the fertilizer and can easily realize the control of the elution rate of fertilizer components. <P>SOLUTION: The granular coated fertilizer formed with coating layers containing a moisture permeable olefonic copolymer and a biodegradable ester oligomer containing the oligomer ester of ethylene glycol and sebacic acid, more particularly the coating layers dispersed with biodegradable ester oligomer- containing discontinuous phases in a moisture permeable olefinic copolymer- containing continuous phase on the surfaces of the granular fertilizer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a granular fertilizer coated with a biodegradable coating. More specifically, the present invention relates to a coated granular fertilizer which exhibits excellent fertilizer elution while using a coating having excellent biodegradability.

[0002]

2. Description of the Related Art Up to now, many coated granular fertilizers have been developed and are already on the market, by coating the surface of granular fertilizer with a coating material such as olefin resin, sulfur, wax or the like to control the elution rate of the fertilizer. ing. By using these coated granular fertilizers, fertilizing effect according to the growth process of crops is expressed,
In recent years, it has become important as a high-performance fertilizer because it can save labor for fertilizer application, improve the utilization rate of fertilizer components to crops, and reduce runoff to groundwater, which has an environmental conservation effect. Is increasing. However, as the use amount of coated granular fertilizer increases, the influence of the coating remaining on the surface or underground after the elution of fertilizer components on the environment is becoming a concern. That is, since an ordinary granular fertilizer coating is poor in biodegradability, it tends to remain without being decomposed on the surface or in the ground for a long period of time. In addition, the white speckled film remaining on the surface of the field damages the landscape of the field, which is not desirable.

As a solution for preventing the coating fertilizer coating from remaining for a long period of time, a method of using a biodegradable material for the coating material of the coated granular fertilizer has been devised, and so far, various chemical compositions as described below have been used. Inventions of biodegradable coated fertilizers have been reported.

Japanese Unexamined Patent Publication (Kokai) No. 7-315976 discloses that granular fertilizer is coated with a film containing a biodegradable aliphatic polyester as an active ingredient.

Japanese Unexamined Patent Publication (Kokai) No. 9-194280 discloses that granular fertilizer is coated with a resin composed of an oxidatively decomposable polyester and a polyolefin or vinylidene chloride, and the coated surface is further coated with the polyester.

Japanese Unexamined Patent Publication No. 9-194281 discloses that granular fertilizer is coated with a resin composed of biodegradable polyester and polyolefin or vinylidene chloride, and the coated surface is further coated with the polyester.

Japanese Unexamined Patent Publication No. 9-249477 discloses that granular fertilizer is coated with a disintegrating coating containing an aliphatic polyester resin as an active ingredient.

Japanese Unexamined Patent Publication No. 9-263476 discloses that granular fertilizer is coated with a composition containing an aliphatic polyester and a polyolefin wax.

Japanese Unexamined Patent Publication No. 9-309784 discloses coating granular fertilizer with a composition comprising a thermoplastic resin (containing a polymeric oxidative decomposition reaction promoting substance) and a biodegradable polyester.

JP-A-11-43391 discloses coating granular fertilizer with a composition comprising an aliphatic polyester, a polyolefin and a photodegrading agent.

Japanese Unexamined Patent Publication (Kokai) No. 11-263689 discloses that granular fertilizer is coated with a coating material containing an aliphatic polyester and microwax.

[0012]

According to the research of the present inventors, the conventionally used granular coated particles having a coating layer formed from a biodegradable polyester resin and a polyolefin (resin) on the surface of the granular particles are However, there are problems such as occurrence of blocking during the coating operation, which is presumed to be caused by the use of the biodegradable polyester resin, and insufficient effect of controlling the elution of the fertilizer component of the coating layer formed on the particle surface. Therefore, the main problem to be solved by the present invention is excellent in spray operability at the time of production of a coated granular fertilizer by spray drying, and the excellent properties such as the film after fertilizer elution is rapidly decomposed or disintegrated in the environment. It is another object of the present invention to provide a coated granular fertilizer which has a fertilizer component and can easily control the elution rate.

[0013]

According to the present invention, the surface of a granular fertilizer contains a biodegradable ester oligomer containing an oligoester of ethylene glycol and sebacic acid in a moisture-permeable olefin copolymer-containing continuous phase. The granular coated fertilizer has a coating layer in which discontinuous phases are dispersed. This coating layer preferably comprises a continuous phase containing 50 to 90% by weight of a moisture-permeable olefin copolymer and a discontinuous phase containing 50 to 10% by weight of a biodegradable ester oligomer. The present invention also provides a granular coated fertilizer comprising a granular fertilizer having a coating layer formed on the surface thereof, the moisture-permeable olefin copolymer, and a biodegradable ester oligomer containing an oligoester of ethylene glycol and sebacic acid. There is also It is preferable that the coating layer contains 10 to 90% by weight of a moisture-permeable olefin copolymer and 90 to 10% by weight of a biodegradable ester oligomer.

The granular coated fertilizer of the present invention is applied to the surface of the field that comes into contact with environmental water. In that state, moisture gradually penetrates the moisture-permeable coating layer of the coated fertilizer and enters the inside,
Dissolve fertilizer components. The fertilizer component aqueous solution generated in this way is eluted mainly outside the coated fertilizer while penetrating mainly through the region where the biodegradable ester oligomer is present. The part occupied by the biodegradable bioester oligomer inside the (coating) becomes a void due to the lowering of the molecule by hydrolysis in the presence of environmental water and subsequent biodegradation, so the coating easily disintegrates with a slight impact. And, for example,
After the elution of fertilizer components, it is easily broken down by work such as plowing in the soil and becomes fine pieces. For this reason, the film is less likely to remain on the surface of the field, and the specific surface area is increased, so that the biodegradability is also improved.

The moisture-permeable olefin copolymer used for forming the coating layer of the granular coated fertilizer of the present invention means an olefin copolymer having higher moisture permeability than polyethylene having the same molecular weight, which is preferable. The moisture-permeable olefin copolymer is an olefin copolymer having a hydrophilic group (eg, lower alkyl ester group such as methyl ester or ethyl ester, carbonyl group, carboxyl group, hydroxyl group) in the side chain.

The biodegradable ester oligomer used for forming the coating layer of the granular coated fertilizer of the present invention is an oligoester of ethylene glycol and sebacic acid, preferably 10% by weight or more, more preferably 30% by weight or more, It is a biodegradable ester oligomer contained. Therefore, another biodegradable ester oligomer may be optionally used in combination.

Both the oligoester of ethylene glycol and sebacic acid, and another biodegradable ester oligomer which may be optionally used, have a number average molecular weight of 1500 to 1
It is preferably in the range of 1500, and the latter is preferably an aliphatic dicarboxylic acid having 2 to 12 carbon atoms and 2 carbon atoms.
It is preferably an oligoester with an aliphatic dialcohol of -12. The biodegradable ester oligomer includes a dehydration reaction between an aliphatic dicarboxylic acid and an aliphatic dialcohol, a transesterification reaction between an aliphatic dicarboxylic acid alkyl ester and an aliphatic dialcohol, and another aliphatic dicarboxylic acid derivative and an aliphatic dialcohol. It can be produced by a reaction with

The biodegradable ester oligomer which may be optionally used in combination has a number average molecular weight of 1500 to 11500, an aliphatic dicarboxylic acid having 3 to 12 carbon atoms and a fatty acid having 2 to 12 carbon atoms. It may be a mixture of an oligoester with a group dialcohol and an oligoester with an oxalic acid and an aliphatic dialcohol having 2 to 12 carbon atoms having a number average molecular weight of 1500 to 15000.

The coating layer may contain a rosin-modified alkyd resin. When the biodegradable ester oligomer forms a discontinuous phase, the rosin-modified alkyd resin is biodegraded to the discontinuous phase. It exists with the functional ester oligomer. The rosin-modified alkyd resin-containing coating layer may further contain a wax, and when the moisture-permeable olefin copolymer forms a continuous phase, the wax is present in the continuous phase.

Although the fertilizer component elution pattern of the granular coated fertilizer of the present invention is usually a linear type (a pattern in which the fertilizer component is eluted immediately after fertilization in a substantially linear curve), the fertilizer component elution pattern is a sigmoid. If you want to use a pattern (a pattern in which the fertilizer components are hardly eluted for a certain period after fertilization and then the fertilizer components are quickly eluted), attach an alkaline material layer between the coating layer and the granular fertilizer. A sigmoidal granular coated fertilizer is obtained by the method.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The granular coated fertilizer of the present invention comprises coating a granular fertilizer with a composition containing a moisture-permeable olefin copolymer and a biodegradable ester oligomer containing an oligoester of ethylene glycol and sebacic acid. Is formed by This coating layer is preferably a coating layer (so-called sea-island structure coating layer) in which a biodegradable ester oligomer-containing discontinuous phase is dispersed in a moisture-permeable olefin copolymer-containing continuous phase.

The composition for forming the coating layer of the granular coated fertilizer of the present invention comprises a moisture-permeable olefin copolymer of 10 to 90% by weight in terms of solid matter and 90 to 10% by weight of an oligoester of ethylene glycol and sebacic acid. It is preferable that the composition contains a biodegradable ester oligomer containing
In particular, when forming a coating layer having a sea-island structure, the composition comprises a moisture-permeable olefin copolymer of 50 to 90% by weight and a biodegradable ester oligomer of 50 to 10% by weight in terms of solid matter. Is preferred.

As the granular fertilizer, urea, ammonium sulfate, sodium nitrate, oxamide, acetaldehyde condensed urea, formaldehyde condensed urea, isobutyraldehyde condensed urea and other nitrogen fertilizer granules, roasted manure, calcined phosphorus fertilizer,
Phosphorus fertilizer granules, such as processed phosphate fertilizers, mixed phosphate fertilizers, and corrosive phosphorus fertilizers, potassium sulfate, potassium chloride, potassium magnesium sulfate, potassium bicarbonate, and potassium fertilizer granules such as potassium silicate fertilizers, phosphorus Granules of chemical fertilizer such as potassium acid fertilizer and potassium nitrate fertilizer, granular organic fertilizer, ammonium nitrate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium chloride, ammonium salts such as ammonium chloride, calcium nitrate, calcium phosphate, calcium sulfate , A calcium salt such as calcium chloride, a magnesium salt such as magnesium nitrate, magnesium phosphate, magnesium sulfate, and magnesium chloride, and a granular fertilizer obtained by granulating a mixture thereof by a method known per se. The granular fertilizer used in the granular coated fertilizer of the present invention is preferably a granular nitrogen fertilizer, particularly granular urea fertilizer or granular ammonium sulfate.

The particle size, particle size distribution and shape of the granular fertilizer are not particularly limited as long as there is no problem in the spraying process or fertilizing work during production, but the particle size is 0.5 mm.
As described above, it is preferably 10 mm or less. If the particle size is smaller than 0.5 mm, the coating surface area per unit weight of the granular fertilizer becomes large, and if spraying is performed with a coating thickness that can control the elution rate, it tends to be difficult to secure the effective amount of the fertilizer. If the particle size is larger than 10 mm, fertilization work becomes difficult. Further, the coverage of the coating material with respect to the granular fertilizer (% by weight of fertilizer) is 0.5% by weight or more and 30% by weight or less, particularly 1% by weight or more, 20% by weight or less, and further 2% by weight or more, It is preferably in the range of about 15% by weight or less.

The moisture-permeable olefin copolymer used for forming the coating layer of the granular coated fertilizer of the present invention is, as described above,
An olefin copolymer having a higher moisture permeability as compared to polyethylene having an equal molecular weight, and a preferred moisture-permeable olefin copolymer has a hydrophilic group (eg, a lower alkyl ester group such as methyl ester or ethyl ester in its side chain, It is an olefin copolymer having a carboxyl group, a carbonyl group, and a hydroxyl group. Specific examples of water-permeable olefin copolymers include ethylene / alkyl acrylate copolymers such as ethylene / methyl acrylate copolymers and ethylene / ethyl acrylate copolymers, ethylene / vinyl acetate copolymers, propylene / An acrylic acid ester copolymer can be mentioned.

Among the above-mentioned moisture-permeable olefin copolymers, ethylene / ethyl acrylate copolymers and ethylene / vinyl acetate copolymers are particularly preferable. ethylene·
The ethyl acrylate copolymer can control the moisture permeability of the coating by changing the content of the ethyl acrylate component, which is the copolymer component, with respect to the ethylene component. The higher is the higher the moisture permeability. Even in an ethylene / vinyl acetate copolymer in which vinyl acetate is used in combination with ethylene as a copolymerization component, the moisture permeability of the film can be changed by adjusting the vinyl acetate content.

In both ethylene-ethyl acrylate copolymer and ethylene-vinyl acetate copolymer,
The content of the copolymerization component (ethyl acrylate or vinyl acetate) with respect to ethylene is preferably 5% by weight or more and 41% by weight or less, more preferably 9% by weight or more and 25% by weight or less. If the content of the copolymerization component is less than 5% by weight, the type of organic solvent capable of dissolving the copolymer is limited, which is a limitation when spraying the coating material solution onto granular fertilizer. There are cases. On the other hand, if the content of the copolymerization component is more than 41% by weight, the melting point of the copolymer is lowered, which may cause problems in spray operability during production and storage of the coated granular fertilizer.

The molecular weight of the ethylene / ethyl acrylate copolymer and the ethylene / vinyl acetate copolymer or the melt flow index, which is an index of the molecular weight, is not particularly limited, but the solubility in an organic solvent, the melting point, and the coated granules are not limited. It is desirable to select it properly considering the film strength of fertilizer.

If desired, the moisture-permeable olefin copolymer may be a polyolefin such as polyethylene, polypropylene or polybutene, an ethylene / propylene copolymer, an ethylene / butene copolymer, a propylene / butene copolymer or a propylene / acrylic acid ester. A copolymer or the like can also be used in combination. Further, a diene-based polymer such as polybutadiene, polyisoprene, polychloroprene, butadiene / styrene copolymer, EPDM copolymer, isoprene / styrene copolymer can be used in combination. It is also possible to control the elution rate of the fertilizer by appropriately combining these.

In the present invention, the biodegradable ester oligomer containing an oligoester of ethylene glycol and sebacic acid used in combination with the moisture-permeable olefin copolymer to form the coating layer has a number average molecular weight of 1500 to 1
It is preferably in the range of 1500.

Ester oligomer (oligoester)
Is preferably an aliphatic oligoester represented by the following general formula and having hydroxyl groups at both ends.

[0032]

[Chemical 1]

[In the formula, k and p are the number of methylene groups of the dialcohol unit constituting the aliphatic oligoester,
m represents the number of methylene groups of the dicarboxylic acid unit constituting the aliphatic oligoester compound, and n represents the number of repeating units of the aliphatic oligoester compound, and 2 ≦
k ≦ 12, 0 ≦ m ≦ 10, n ≧ 1, and 2 ≦ p ≦ 12
Is an integer that satisfies

Number average molecular weight of aliphatic oligoester (M
It is particularly preferable that n) is 2000 or more and 11500 or less, and the weight average molecular weight (Mw) is 500.
It is preferably 0 or more and 50,000 or less. The carboxyl end group concentration [COOH] of the aliphatic oligoester is preferably 1.0 × 10 ⁻⁵ (mol / g) or less.

The number of methylene groups in the dialcohol unit is represented by k and p in the above formula, and both are integers in the range of 2 to 12 (preferably 2 to 6). Examples of the aliphatic dialcohol which forms such a dialcohol unit include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol and 1,7-heptane. Examples thereof include diol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol and 1,12-dodecanediol. Two or more kinds of these aliphatic dialcohol compounds may be used in combination.

The number of methylene groups in the aliphatic dicarboxylic acid unit is represented by m in the above formula and is an integer in the range of 0 to 12 (preferably 0 or 4 to 10, more preferably 0 or 6 to 10). Is. Examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, and dodecanedioic acid. Reactive derivatives of these aliphatic dicarboxylic acids (eg, halides, esters, anhydrides) may be used. Moreover, you may use together two or more types of aliphatic dicarboxylic acid or its reactive derivative. In this case,
A part (less than 50 mol%, particularly less than 30 mol%) of the above-mentioned aliphatic dicarboxylic acid may be replaced with an aromatic dicarboxylic acid compound. Examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid and terephthalic acid.

The number average molecular weight Mn (g · mol ⁻¹ ) of the aliphatic oligoester represented by the above formula is 1500 ≦ Mn ≦ 15000 when the aliphatic dicarboxylic acid is oxalic acid.
Preferably satisfies 2000 ≦ Mn ≦ 1500
It is more preferable to satisfy 0. When the aliphatic dicarboxylic acid is other than oxalic acid, 1500 ≦ Mn ≦
It is preferable to satisfy 11500, and 2000 ≦ Mn
It is more preferable to satisfy ≦ 11000. When Mn is less than 1500, the melting point may be lowered or the coating strength of the coated granular fertilizer formed may be lowered, and the load during storage or fertilization work may not be able to be withstood. On the other hand, when Mn becomes too large, the viscosity of the organic solvent solution of the coating material becomes high, and the spray operability at the time of coating the granular fertilizer tends to deteriorate. The carboxyl end group concentration [COOH] of the aliphatic oligoester is 1.0
It is preferably × 10 ⁻⁵ (mol / g) or less. [COOH] is 1.0 × 10 ^-5 (mol / g)
If the concentration is higher, that is, the concentration of the hydroxyl terminal is lowered, the moisture permeability of the coating containing the aliphatic oligoester compound as an active ingredient tends to be lowered.

The oligoester represented by the above formula and having hydroxyl groups at both ends is, for example, dehydrated from the above-mentioned aliphatic dialcohol and aliphatic dicarboxylic acid (or its derivative such as ester or halide). It can be produced by a condensation reaction. As the combination of the aliphatic dialcohol and the aliphatic dicarboxylic acid (or its reactive derivative), one type or two or more types are selected in consideration of the melting point, crystallinity and the like. From the environment where the coated granular fertilizer is exposed during distribution or storage, it is necessary to pay attention to the melting point of the produced oligoester, and it is preferable to combine them so that the melting point of the product is 60 ° C or higher.
The molar ratio of the aliphatic dialcohol charged is 1.01 mol or more and 2 mol or less, more preferably 1.05 mol or more, with respect to 1 mol of the aliphatic dicarboxylic acid, with the aliphatic dialcohol in excess. It should be 1.2 mol or less.

The reaction temperature and pressure of the dehydration (or alcohol) condensation reaction for producing the aliphatic oligoester are not particularly limited as long as the above-mentioned object is obtained, but the reaction temperature is 120 ° C. or higher, It is preferably 350 ° C. or lower, the pressure during the reaction is 1 mmHg or higher,
It is preferably 760 mmHg or less. The temperature and pressure conditions can be changed during the reaction so that the dehydration condensation reaction proceeds rapidly to obtain the above-mentioned target product. Also,
A known catalyst can be added to the dehydration condensation reaction to accelerate the reaction. The catalyst that can be used is a metal compound such as titanium, zinc, germanium, iron or tin, and titanium tetrabutoxide or the like is particularly preferable. The amount of catalyst added and the timing of catalyst addition in the reaction process are not particularly limited as long as the above-mentioned target product can be obtained promptly.

In the above general formula, when m is 0,
It is an oligoester of oxalic acid and an aliphatic dialcohol (an oligoester in which oxalic acid units and aliphatic dialcohol units are alternately arranged, referred to as oxalic acid oligoester in the present specification). The number average molecular weight of this oxalic acid oligoester is 2,000 or more and 15,000.
The following is particularly preferable, and the weight average molecular weight is preferably 5,000 or more and 50,000 or less. The concentration of carboxyl terminal groups of the oxalic acid oligoester is preferably 1.0 × 10 ⁻⁵ (mol / g) or less.

The oxalic acid oligoester having hydroxyl groups at both ends can be easily produced by subjecting the above-mentioned aliphatic dialcohol and oxalic acid diester to dealcoholization condensation reaction. As the combination of the aliphatic dialcohol and the oxalic acid diester, one type or two or more types are selected in consideration of the melting point, the crystallinity and the like. Considering the environment to which the coated granular fertilizer is exposed during distribution or storage, the melting point of the oxalic acid oligoester to be formed should be particularly noted, and it is preferable to combine the products so that the melting point of the product is 60 ° C or higher. . The molar ratio of the aliphatic dialcohol charged is 1.01 mol or more and 2 mol or less, more preferably 1 mol per mol of oxalic acid or its reactive derivative (eg, diester) with the aliphatic dialcohol in excess. ．
The amount is not less than 05 mol and not more than 1.2 mol.

The reaction temperature and pressure of the dehydration (alcohol) condensation reaction for producing the oxalic acid oligoester are not particularly limited as long as the above-mentioned object can be obtained, but the reaction temperature is 120 ° C. or higher and 350 ° C. It is preferable that the pressure is 1 mmHg or more and 760 mmH during the reaction.
It is preferably g or less. The temperature during the reaction, so that the dehydration condensation reaction proceeds promptly to obtain the target product,
The pressure conditions can be varied. A known catalyst can be added to the dehydration (alcohol) condensation reaction to accelerate the reaction. The catalyst that can be used is a metal compound such as titanium, zinc, germanium, iron or tin, and titanium tetrabutoxide or the like is particularly preferable. The amount of catalyst added and the timing of catalyst addition in the reaction process are not particularly limited as long as the above-mentioned target product can be obtained promptly.

As described above, the biodegradable ester oligomer of the coating layer of the coated granular fertilizer of the present invention is a biodegradable ester oligomer containing an oligoester of ethylene glycol and sebacic acid, which is ethylene glycol and sebacine. It is preferable to use an oligoester of an acid alone or a combination of an oligoester of ethylene glycol and sebacic acid with another ester oligomer. In this case, the oligoester of ethylene glycol and sebacic acid is usually used in an amount of 1% by weight or more, preferably 10% by weight or more, and more preferably 30% by weight or more of the biodegradable ester oligomer.

The coating layer of the coated granular fertilizer may contain a rosin-modified alkyd resin. When the biodegradable ester oligomer forms a discontinuous phase, the rosin-modified alkyd resin is a discontinuous one. Present in phase with biodegradable ester oligomer. Rosin-modified alkyd resin is
It also functions as a biodegradable ingredient.

The rosin-modified alkyd resin-containing coating layer comprises
Additionally, a wax may be included and is present in the moisture permeable olefin copolymer, if it forms the continuous phase.

The rosin-modified alkyd resin can be obtained by reacting a rosin collected from pine resin, an unsaturated polycarboxylic acid and a polyhydric alcohol, and is commercially available. More specifically, rosin is a tan solid that is obtained from pine resin by steam distillation to remove turpentine oil and is crystalline at room temperature. The main component of rosin is a mixture containing several isomers of diterpene-type carboxylic acids such as abietic acid, neoabietic acid, levopimaric acid, pimaric acid, and dextropimaric acid.

A typical rosin-modified alkyd resin is obtained by adding an unsaturated polyvalent carboxylic acid such as fumaric acid, maleic acid or maleic anhydride to rosin by a Diels-Alder reaction, and further adding a polyvalent glycerin or pentaerythritol. It can be obtained by dehydration condensation reaction with alcohol.

In the rosin-modified alkyd resin, the molecular weight and the solubility in various solvents can be controlled by changing the types and amounts of unsaturated polycarboxylic acid and polyhydric alcohol to be reacted with rosin. For example, by decreasing the amount of unsaturated polycarboxylic acid added, the solubility in a non-polar solvent such as drying oil or benzene can be increased. On the contrary, by decreasing the amount of polyhydric alcohol used to increase the amount of free carboxyl groups or suppressing the progress of esterification, the amount of free hydroxyl groups can be increased, and the amount of free hydroxyl groups to polar solvents such as alcohol can be increased. The solubility can also be increased.

In the coated granular fertilizer of the present invention, the rosin-modified alkyd resin which can be introduced into the coating layer has a wettability with water in order to prevent deterioration of biodegradability and moisture permeability of the coating film formed. Those having good alcohol solubility are preferable. Among them, the acid value measured according to the method specified in JIS K-5903 is 10 or more, particularly 10 or more.
A rosin-modified alkyd resin having 0 or more can be preferably used. Considering the temperature conditions of the coated granular fertilizer of the present invention during distribution or storage, a rosin-modified alkyd resin having a softening point of 60 ° C. or higher and a number average molecular weight of 300 to 1500 is preferable.

In the coated granular fertilizer of the present invention, waxes that can be introduced into the coating layer have a melting point of 50.
It is preferable that the temperature is not less than 120 ° C., not more than 120 ° C., especially not less than 60 ° C. and not more than 100 ° C., for example, paraffin wax, microcrystalline wax, beeswax, wood wax,
Carnauba wax and the like are mentioned, but paraffin wax and microcrystalline wax are particularly suitable substances. Paraffin wax is a room temperature solid hydrocarbon containing normal paraffin as a main component, and microcrystalline wax is a room temperature solid hydrocarbon containing isoparaffin and cycloparaffin as a main component.
Since paraffin wax and microcrystalline wax do not contain a polar group, the degradable coated granular fertilizer of the present invention is also effective for suppressing the moisture permeability of the coating material. The molecular weight is preferably about 30 to 100 as the number of carbon atoms contained.

The preferable ratio of each component forming the coating layer of the granular coated fertilizer of the present invention is as follows.

[0052]

[Table 1] ────────────────────────────────────     Coating layer forming material Preferred range Particularly preferred range ──────────────────────────────────── Breathable olefin copolymer 15-80% by weight 20-60% by weight Biodegradable ester oligomer total amount 15-70% by weight 20-60% by weight Rosin-modified alkyd resin 1-30% by weight 3-25% by weight Wax 0-50% by weight 0-40% by weight ────────────────────────────────────

The preferred amount of each component forming the coating layer of the granular coated fertilizer of the present invention is as follows, expressed in parts by weight with respect to 100 parts by weight of the moisture-permeable olefin copolymer.

[0054]

[Table 2] ────────────────────────────────────     Coating layer forming material Preferred range Particularly preferred range ──────────────────────────────────── Breathable olefin copolymer 100 parts by weight 100 parts by weight Biodegradable ester oligomer (total amount) 19-466 parts by weight 33-300 parts by weight Rosin-modified alkyd resin 1-200 parts by weight 5-125 parts by weight Wax 0-333 parts by weight 0-200 parts by weight ────────────────────────────────────

The coating layer of the coated granular fertilizer of the present invention may contain other additive components in order to adjust properties such as moisture permeability and decomposability, as long as the elution limiting function of the fertilizer components is not impaired. You can For example, talc, clay, silica, zeolite, zonotolite, kaolin, bentonite, calcium carbonate, magnesium carbonate, diatomaceous earth, and other inorganic fillers, starch, chitin are used as additives that have the effect of delaying or promoting the dissolution rate of fertilizer components. An organic filler such as can be added. Further, the dissolution rate of the fertilizer component can be adjusted by increasing the compatibility between the coating layer forming materials. Examples of the additives that can be used are long-chain saturated or unsaturated fatty acids, and surfactants composed of derivatives thereof, maleic anhydride-modified polyolefin, maleic anhydride-modified polystyrene, modified wax, styrene-based thermoplastic stramer, ethylene. -Compatibilizers such as propylene rubber are included.

The above-mentioned additive components are introduced into the coating by simultaneously dissolving them in an organic solvent solution of the coating material (coating layer forming material) and spraying them on the granular fertilizer under flowing hot air. When the additive component does not dissolve in the organic solvent, it can be sprayed while being dispersed in the solvent, but the pipe, pump,
Since there is a risk of clogging at nozzles etc., the amount used for all coating materials should be adjusted appropriately. The preferable amount of the additive component with respect to the total coating material is 0.01% by weight or more and 50% by weight or less.

The coated granular fertilizer of the present invention can be produced by a known method of spraying an organic solution of the coating material while flowing the granular fertilizer by using hot air. It is necessary to consider the solubility of the coating material. Typical examples of organic solvents that can be used are methyl ethyl ketone, methyl isobutyl ketone, N, N-dimethylacetamide, N, N-dimethylformamide, and chlorinated hydrocarbons represented by chloroform, methylene chloride, 1,2-dichloroethane and the like. Examples of the solvent include aromatic solvents represented by benzene, toluene, xylene, orthodichlorobenzene, and mixed solvents containing two or more of them.

The coating material solution concentration is 5% by weight or more and is 1
It is preferably about 5% by weight or less. When the concentration is higher than 15% by weight, the solution viscosity becomes high, and clogging of pipes, pumps, and nozzles due to precipitation of solids is likely to occur.
If the concentration is lower than 5% by weight, a large amount of organic solvent will be used, and a large-scale facility for solvent recovery and environmental pollution countermeasures will be required.

As described above, the granular coated fertilizer of the present invention is
By adding an alkaline material layer between the granular fertilizer and the coating layer, a sigmoid type coated fertilizer can be obtained. The alkaline material is an inorganic compound or an organic compound that exhibits alkalinity in an aqueous solution, and particularly preferably an alkaline substance that gently reacts with water. As the alkaline material, carbonates, hydroxides or oxides of alkaline earth metals, carbonates, phosphates or silicates of alkali metals, organic acid salts of alkali metals, and alkylamides are preferable. Specific examples of those materials include calcium carbonate, calcium oxide, calcium hydroxide, magnesium carbonate, magnesium hydroxide, magnesium oxide, sodium carbonate, potassium carbonate, tripotassium phosphate, tripotassium silicate, sodium silicate, acetic acid. Mention may be made of sodium, acetamide, propionamide, and butyramide.

The alkali material layer is usually formed from the above-mentioned alkali material and a resin material which functions as a binder. As the resin material used as the binder in the alkaline material layer, for example, various resin materials listed as the material for forming the coating layer can be used. In particular, the alkaline material layer preferably contains a moisture-permeable olefin copolymer, a biodegradable ester oligomer, a rosin-modified alkyd resin, and / or wax in an amount of 20 to 80% by weight based on the total amount.

A sigmoid type granular coated fertilizer itself obtained by coating a granular fertilizer with a coating layer and an alkaline material intermediate coating layer is already known, and regarding the constitution and production of the sigmoid type granular coated fertilizer according to the present invention, Those known methods can be used.

The fertilizer elution characteristics from the coated granular fertilizer produced by the present invention can be examined by a fertilizer elution test in water. It is known that this method is effective not only for simulating fertilizer elution in paddy fields and hydroponics, but also for predicting fertilizer release in soil of fields.

The biodegradability of the coating layer can be examined by a long-term soil burying test or an acceleration test in compost.

Hereinafter, the present invention will be described more specifically based on Examples and Comparative Examples.

[0065]

Examples (1) Production of oligoester of ethylene glycol and sebacic acid (EG-SEA) 1 mol of sebacic acid and 1.1 mol of ethylene glycol were charged into a 500 mL flask, and the inside of the flask was replaced with nitrogen. The flask was heated to 160 ° C. and stirred at normal pressure for 1 hour, then at 170 ° C. for 2 hours and at 180 ° C. for another 2 hours. Then, the pressure in the flask was reduced to 100 mmHg, and the mixture was stirred for 0.5 hour, then 50 mmHg for 0.5 hour, and further 10 mmHg for 2 hours. After returning to normal pressure, 9.5 mg of titanium tetrabutoxide was added, and 10 mm was added again.
After stirring under reduced pressure of Hg for 8 hours, the dehydration condensation reaction was completed to obtain EG-SEA (number average molecular weight: 5100, weight average molecular weight: 15000, melting point: 72.5 ° C).

(2) Production of oligoester (HD-OD) of 1,6-hexanediol and oxalic acid 3.15 mol of dimethyl oxalate, 4.5 mol of 1,6-hexanediol, and titanium tetrabutoxide 0 .0
78 mmol was attached to a reflux distiller equipped with a condenser 1
The flask was charged into a 000 mL flask, and the inside of the flask was replaced with nitrogen. After heating the flask to 160 ° C and stirring at atmospheric pressure for 3 hours, the pressure inside the flask was reduced to 300 mmHg and 170 ° C.
It was stirred for 1 hour. Then 100 mmHg in the flask
The mixture was depressurized to 180 ° C. for 5 hours, then depressurized to 5 mmHg and stirred for 2 hours to complete the demethanol condensation reaction to obtain HD-OD.

(3) Measurement of dissolution rate Using granular urea coated with various coating materials, changes in the dissolution rate (%) of the urea component were measured. The measurement was carried out using the "Urea dissolution test method"("Fertilizer analysis method" issued by the Ministry of Agriculture, Forestry and Fisheries, National Institute for Agro-Environmental Technology, December 25, 1992, except that the temperature of the constant temperature bath was controlled at 35 ± 1 ° C). The dissolution rate was as described in Section 5.33.).

(4) Biodegradability evaluation test A pinhole was opened with a needle for each coated granular urea, and the granular urea was allowed to stand still in water to completely elute the urea inside. 20 hollow capsule capsules obtained after drying were weighed in advance. Compost was put into a cup having a volume of 200 mL so that the thickness of the compost was about 3 cm, and 20 hollow capsules were placed on the compost. 2.5 cm of compost from above
It was gently placed to a depth of about a certain degree, and left as it was in a constant temperature bath at 30 ° C. After burying for a predetermined time, the compost was removed with a spatula, and the hollow capsule capsule was carefully taken out. After the treatment, the hollow coated capsules were gently washed with water to remove the adhering compost, and dried, and the weight residual rate (%) was evaluated by weight measurement. The calculation method is as follows.

[0069]

[Equation 1] Weight residual rate (%) = W / W _O × 100

In the above calculation formula, W is the weight (mg) of the capsule capsule after the embedding treatment, and W _O is the weight (mg) of the capsule capsule before the embedding treatment.

Example 1 Oligoester of ethylene glycol and sebacic acid (EG-SEA), and rosin-modified alkyd resin (manufactured by Arakawa Chemical Industry Co., Ltd., Marquid No. 31, acid value 185, softening point 140 ° C.) , MAR)
Was used as the biodegradable active ingredient. 2 with cooling tube
In a 000 mL flat bottom separable flask, 880 parts by weight of a toluene / methyl ethyl ketone (1/1 weight ratio) mixed solvent, 31.2 parts by weight of EG-SEA, 7.8 parts by weight of MAR, and ethylene / ethyl acrylate copolymer. (Mitsui DuPont Polychemical Co., Ltd., A702, ethyl acrylate content 19% by weight, MI = 5, EEA-1).
2 parts by weight, and 1 microcrystalline wax (manufactured by Nippon Seiro Co., Ltd., Hi-Mic-3090, WAX)
1.7 parts by weight was added, and the mixture was stirred with heating to dissolve it. The coating material solution concentration is 8.5% by weight. Height 1500m
1300 parts by weight of 6 mesh under and 9 mesh on granular urea were charged into an acrylic resin spraying fluid tank having a diameter of 230 mm and a diameter of 230 mm, and was made to flow from the lower portion of the fluid tank by hot air from a blower. An organic solvent solution of the coating material was sent by a pump and sprayed from the bottom of the fluidized tank. The temperature of the hot air was controlled so that the temperature inside the fluidized tank was 52 ° C to 53 ° C. The spraying process time was about 15 minutes. For 30 minutes after the end of spraying, the mixture was kept flowing with hot air from a blower, dried and cooled to produce coated granular urea with a coverage of 6.3% by weight. The fluidity of the granular urea in the spraying process was very good and no blocking occurred. The coating layer of the obtained granular coated fertilizer has a structure in which a discontinuous phase containing an oligoester of ethylene glycol and sebacic acid and a rosin-modified alkyd resin is dispersed in a continuous phase composed of an ethylene / ethyl acrylate copolymer. Was becoming.

Example 2 Oligoester of ethylene glycol and sebacic acid (EG-SEA), oligoester of 1,6-hexanediol and oxalic acid (HD-
OD), and rosin-modified alkyd resin (MAR) were used as biodegradable active ingredients. EG-SEA 15.
6 parts by weight, HD-OD 15.6 parts by weight, and MAR 7.
A coating operation was performed under the same conditions as in Example 1 except that 8 parts by weight and a coating material containing 31.2 parts by weight of EEA-1 were used to produce a coated granular urea having a coating rate of 6.3% by weight. . The fluidity of granular urea in the spraying process is very good,
No blocking occurred either.

[Example 3] An oligoester of ethylene glycol and sebacic acid (EG-SEA) was used as a biodegradable active ingredient. In a 2000 mL flat bottom separable flask equipped with a cooling tube, 1008 parts by weight of a mixed solvent of toluene / methyl ethyl ketone (1/1 by weight), EG-
SEA (39 parts by weight), EEA-1 (39 parts by weight), and WAX (15.6 parts by weight) were added, and the mixture was stirred with heating to dissolve it. The coating material solution concentration is 8.5% by weight. Height 1
Granular urea with 6 mesh under and 9 mesh on in a spray flow tank made of acrylic resin with a diameter of 500 mm and a diameter of 230 mm.
300 parts by weight were charged and flowed from the lower part of the flow tank by hot air from a blower. An organic solvent solution of the coating material was sent by a pump and sprayed from the bottom of the fluidized tank. In order to keep the temperature inside the fluidized tank from 52 ℃ to 53 ℃,
The temperature of hot air was controlled. The spraying process time was about 15 minutes. For 30 minutes after the end of spraying, the mixture was kept flowing with hot air from a blower, dried and cooled to produce coated granular urea with a coverage of 7.2% by weight. The fluidity of the granular urea in the spraying process was very good and no blocking occurred. The coating layer of the obtained granular coated fertilizer had a structure in which a discontinuous phase of an oligoester of ethylene glycol and sebacic acid was dispersed in a continuous phase composed of an ethylene / ethyl acrylate copolymer.

Example 4 An oligoester of ethylene glycol and sebacic acid (EG-SEA) was used as a biodegradable active ingredient. The coating operation was performed under the same conditions as in Example 3 except that the amount of EG-SEA used was 52 parts by weight and the amount of EEA-1 used was 26 parts by weight, and the coated granular urea had a coverage of 7.2% by weight. Was manufactured. The fluidity of the granular urea in the spraying process was very good and no blocking occurred.

Example 5 An oligoester of ethylene glycol and sebacic acid (EG-SEA) and a rosin-modified alkyd resin (MAR) were used as biodegradable active ingredients. In a 2000 mL flat bottom separable flask equipped with a cooling tube, add toluene / methyl ethyl ketone (1/1
Weight ratio) 980 parts by weight of mixed solvent and 2 parts of EG-SEA
7.3 parts by weight, ethylene / ethyl acrylate copolymer (EEA-1) 18.2 parts by weight, paraffin wax (Nippon Seiwa Co., Ltd. FT-0165, WAX-1) 45.4 parts by weight. And 5.0 parts by weight of MAR were added and dissolved by stirring under heating to prepare an outer coating layer forming material solution. 2000m with cooling pipe
In an L flat bottom separable flask, 130 parts by weight of a mixed solvent of toluene / methyl ethyl ketone (1/1 by weight), 5.9 parts by weight of calcium hydroxide, and 27.3 of EG-SEA were mixed.
5.9 parts by weight of ethylene / ethyl acrylate copolymer (NUC6570, manufactured by Nippon Unicar Co., Ltd., ethyl acrylate content 25% by weight, EEA-2) was added, and the mixture was stirred under heating. By dissolving, an alkaline material layer (intermediate coating layer) forming material solution was prepared. Height 1
Granular urea with 6 mesh under and 9 mesh on in a spray flow tank made of acrylic resin with a diameter of 500 mm and a diameter of 230 mm.
300 parts by weight were charged and flowed from the lower part of the flow tank by hot air from a blower. First, the alkaline material layer forming material solution was sent by a pump and sprayed in the form of a spray from the lower part of the fluidized tank. The temperature of the hot air was controlled so that the temperature inside the fluidized tank was 52 ° C to 53 ° C. Next, the outer coating layer forming material solution was sent by a pump and sprayed from the lower part of the fluidized tank. The temperature inside the fluidized tank is from 52 ° C to 53
The temperature of the hot air was controlled so as to be ℃. For 30 minutes after the spraying of the outer coating layer forming material solution is continued to flow with hot air from the blower, it is dried and cooled to obtain a coating rate (total of the intermediate coating layer and the outer coating layer) of 8.3% by weight. A coated granular urea was prepared. The fluidity of the granular urea in the spraying process was very good and no blocking occurred.

Example 6 Oligoester of ethylene glycol and sebacic acid (EG-SEA), oligoester of 1,6-hexanediol and oxalic acid (HD-
OD), and rosin-modified alkyd resin (MAR) were used as biodegradable active ingredients. 3 parts by weight HD-OD
Was added, and the coating operation was performed under the same conditions as in Example 5 except that the same amount of microcrystalline wax (WAX) was used as the wax to produce a coated granular urea with a coating rate of 8.5% by weight. The fluidity of the granular urea in the spraying process was very good and no blocking occurred.

Example 7 An oligoester of ethylene glycol and sebacic acid (EG-SEA) and a rosin-modified alkyd resin (MAR) were used as biodegradable active ingredients. As a wax, M manufactured by China Oil Co., Ltd.
Example 5 except PS-2 (WAX-2) was used in the same amount.
The coating operation was carried out under the same conditions as above to produce coated granular urea with a coating rate of 8.3% by weight. The fluidity of the granular urea in the spraying process was very good and no blocking occurred.

Example 8 Oligoester of ethylene glycol and sebacic acid (EG-SEA), oligoester of 1,6-hexanediol and oxalic acid (HD-
OD), and rosin-modified alkyd resin (MAR) were used as biodegradable active ingredients. NUC6 manufactured by Nippon Unicar Co., Ltd. as an ethylene / ethyl acrylate copolymer
170, ethyl acrylate content: 18% by weight, EEA
A coating operation was performed under the same conditions as in Example 6 except that the same amount of -2) was used to produce a coated granular urea having a coating rate of 8.5% by weight. The fluidity of the granular urea in the spraying process was very good and no blocking occurred.

Comparative Example 1 Instead of EG-SEA, polybutylene succinate (commercially available aliphatic polyester:
Showa Highpolymer Co., Ltd., Bionole # 1020, hereinafter, B
A coating operation was performed under the same conditions as in Example 1 except that the same amount of io-1 (melting point: 114 ° C.) was used to produce a coated granular urea having a coating rate of 6.3% by weight. The fluidity of granular urea in the spraying process was very poor. However, blocking did not occur.

[Comparative Example 2] A coating operation was performed under the same conditions as in Example 3 except that the same amount of polybutylene succinate (Bio-1) was used instead of EG-SEA, and the coating rate was 7.2. A wt% coated granular urea was prepared. The flowability of granular urea in the spraying process was very poor and rocking also occurred.

[Comparative Example 3] A coating operation was performed under the same conditions as in Example 4 except that the same amount of polybutylene succinate (Bio-1) was used instead of EG-SEA, and the coating rate was 7.2. A wt% coated granular urea was prepared. The fluidity of granular urea in the spraying process was very poor. However, blocking did not occur.

[Results of biodegradability evaluation test of coating film] The test results of the biodegradability evaluation of the coating layer of the coated granular urea produced in Examples and Comparative Examples are shown in FIG. 1 (Example 1, Example 2, Comparison). Example 1, Comparative Example 2), FIG. 2 (Example 3, Comparative Example 5), and FIG. 3 (Example 4, Comparative Example 3).

[Change in dissolution rate of coated granular urea] Changes in dissolution rate of coated granular urea produced in Examples and Comparative Examples are shown in FIG. 4 (Example 1, Example 2, Example 4, Comparative Example 2, Comparative Example). 3).

As is clear from the results shown in FIGS. 1 to 4, the coated granular fertilizer using the coating material of the present invention is excellent in its biodegradability and is rapidly eluted.

Oligoesters of ethylene glycol and sebacic acid (EG-SEA) contained in the biodegradable oligomer used in the present invention, and oligoesters of 1,6-hexanediol and dodecanedioic acid (HD-DD).
A) and a graph showing the tendency of biodegradability of an oligoester of ethylene glycol and dodecanedioic acid (EG-DDA) is shown in FIG. From the results shown in FIG. 5, oligoesters of ethylene glycol and sebacic acid (E
It can be seen that G-SEA) is particularly excellent in biodegradability.

[0086]

INDUSTRIAL APPLICABILITY The granular coated fertilizer of the present invention is superior to the known coated granular fertilizer in spraying operability and biodegradability during production, and can control the elution rate of the fertilizer.

[Brief description of drawings]

FIG. 1 is a graph showing test data of biodegradability of coatings of coated granular fertilizers of Examples 1 and 2 and Comparative Examples 1 and 2.

FIG. 2 is a graph showing test data of biodegradability of coatings of coated granular fertilizers of Example 3 and Comparative Example 2.

FIG. 3 is a graph showing test data of biodegradability of coatings of coated granular fertilizers of Example 4 and Comparative Example 3.

FIG. 4 is a graph showing changes in the water elution characteristics of the coated granular fertilizers of Examples 1, 2, 4 and Comparative Examples 2, 3.

FIG. 5: Oligoester of ethylene glycol and sebacic acid (EG-SEA), oligoester of 1,6-hexanediol and dodecanedioic acid (HD-DDA), and oligoester of ethylene glycol and dodecanedioic acid. It is a graph which shows the tendency of biodegradability of (EG-DDA).

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // (C08L 23/08 C08L 67:02 67:02) (72) Inventor Koichiro Kurachi Ube City, Yamaguchi Prefecture Kobushi 5 at 1978 Ube Research Co., Ltd. Ube Laboratory (72) Inventor Katsuhide Futani 7 in 1988 Kogushi, Ube City, Yamaguchi Prefecture 7 Ube Kosan Agricultural Co., Ltd. F-term (reference) 4H061 AA01 BB15 DD04 DD18 EE27 EE35 FF08 FF15 GG15 GG19 HH45 4J002 BB071 CF013 CF032 EH086 GA00

Claims (21)

[Claims] 1. A coating layer in which a discontinuous phase containing a biodegradable ester oligomer containing an oligoester of ethylene glycol and sebacic acid in a continuous phase containing a moisture-permeable olefin copolymer is dispersed on the surface of a granular fertilizer. Granular coated fertilizer formed by forming. 2. The granular material according to claim 1, wherein the coating layer comprises a continuous phase containing 50 to 90% by weight of a moisture-permeable olefin copolymer and a discontinuous phase containing 50 to 10% by weight of a biodegradable ester oligomer. Coated fertilizer. 3. The granular coated fertilizer according to claim 1, wherein the moisture-permeable olefin copolymer is an olefin copolymer having a hydrophilic group in its side chain. 4. The granular coated fertilizer according to claim 3, wherein the moisture-permeable olefin copolymer having a hydrophilic group is an ethylene / alkyl acrylate copolymer. 5. The granular coated fertilizer according to claim 1, wherein the biodegradable ester oligomer-containing discontinuous phase further contains a rosin-modified alkyd resin. 6. The method according to claim 1, wherein the moisture-permeable olefin copolymer-containing continuous phase further contains a wax, and the biodegradable ester oligomer-containing discontinuous phase further contains a rosin-modified alkyd resin. Granular coated fertilizer. 7. The granular coated fertilizer according to claim 1, wherein an alkaline material layer is provided between the coating layer and the granular fertilizer. 8. The granular fertilizer is granular nitrogen fertilizer.
The granular coated fertilizer according to any one of 1 to 7. 9. A granular coated fertilizer in which a coating layer containing a moisture-permeable olefin copolymer and a biodegradable ester oligomer containing an oligoester of ethylene glycol and sebacic acid is formed on the surface of the granular fertilizer. 10. The granular coated fertilizer according to claim 9, wherein the coating layer contains 10 to 90% by weight of a vapor-permeable olefin copolymer and 90 to 10% by weight of a biodegradable ester oligomer. 11. The granular coated fertilizer according to claim 9, wherein the moisture-permeable olefin copolymer is an olefin copolymer having a hydrophilic group in its side chain. 12. The granular coated fertilizer according to claim 11, wherein the moisture-permeable olefin copolymer having a hydrophilic group is an ethylene / alkyl acrylate copolymer. 13. The granular coated fertilizer according to claim 9, wherein the coating layer further contains a rosin-modified alkyd resin. 14. The granular coated fertilizer according to claim 9, wherein the coating layer further contains wax and a rosin-modified alkyd resin. 15. The granular coated fertilizer according to claim 9, wherein an alkaline material layer is provided between the coating layer and the granular fertilizer. 16. The granular coated fertilizer according to claim 9, wherein the granular fertilizer is granular nitrogen fertilizer. 17. A composition comprising 10 to 90% by weight of a moisture permeable olefin copolymer and 90 to 10% by weight of a biodegradable ester oligomer containing an oligoester of ethylene glycol and sebacic acid. 18. The composition according to claim 17, wherein the moisture-permeable olefin copolymer is an olefin copolymer having a hydrophilic group in a side chain. 19. The composition according to claim 18, wherein the moisture-permeable olefin copolymer having a hydrophilic group is an ethylene / alkyl acrylate copolymer. 20. The composition according to claim 17, further comprising a rosin-modified alkyd resin. 21. The composition according to claim 17, which further contains a wax.