JPH08333185A - Resin coated fertilizer - Google Patents

Abstract

PURPOSE: To enable the substential biodegradation of a coating material at the time when a delayed release fertilizer loses its effect by coating the fertilizer with a biodegradable plastic obtained by blending starch or its modified material and an organometallic compound with a base polymer. CONSTITUTION: Biodegradable plastics are prepared by blending starch or a modified starch obtained by grafting a polymerizable monomer such as styrene or that coated with silicon, etc., with a thermoplastic resin or a mixture of one or more kinds of thermoplastic resin, preferably an ethylene-vinyl acetate copolymer and/or a low-density polyethylene and at least one kind of the salt, oxide, hydroxide or organometallic compound of a metal selected from Fe, Al, K, Ca, Mg, Zn, Mn, etc. Then, fertilizer in an arbitrary form of granules, balls or cylinders is coated with the biodegradable plastic to give the objective resin-coated delayed release fertilizer.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a resin-coated fertilizer obtained by coating a fertilizer component with a resin material.

[0002]

2. Description of the Related Art Studies on slowing the elution rate of fertilizer components to impart slow-acting or slow-acting properties to sustain the fertilizing effect for a long period of time have been conducted for a long time. Resin coated fertilizer coated with material has been developed and put into practical use.

[0003]

However, in the conventional resin-coated fertilizer, it was difficult to adjust the time when the fertilizing effect was exhibited depending on the crop.

Further, the coating resin material generally used in the conventional resin-coated fertilizer can be disintegrated under the influence of ultraviolet rays or the like for a certain period of time to elute the fertilizer component enclosed therein, but It was not biodegradable by being decomposed by microorganisms. Therefore,
Even after the fertilization was completed, only the resin coating material remained in the soil, which significantly impaired the landscape and adversely affected the growth of crops and the surrounding environment.

Some attempts have been made to use polycaprolactan having excellent biodegradability as a coating resin material, but polycaprolactan is decomposed and disappears in a short period due to its property. In addition, the sustained release property, which maintains the fertilizing effect for a long period of time, becomes poor. In addition, since it is extremely expensive, it is practically difficult to use it for a fertilizer that needs to be used in a large amount.

[0006]

In order to solve the problems of the prior art, the present invention controls the elution rate of fertilizer components while maintaining the fertilizing effect for a long period of time.
Moreover, it is an object of the present invention to provide a resin-coated fertilizer capable of substantially completely biodegrading a resin coating material almost at the end of fertilization.

To achieve this object, the resin-coated fertilizer according to the present invention is characterized in that the fertilizer is coated with a biodegradable plastic obtained by blending a base polymer with at least starch or a modified product thereof and an organometallic compound. And

The above-mentioned base polymer is a polyolefin-based material comprising homopolymers or copolymers of α-olefins such as polyethylene (PE) and polypropylene (PP), or copolymers of these α-olefins with other comonomers. From thermoplastic resins such as resin, polyvinyl alcohol (PVA) resin, polystyrene resin, ABS resin, polyvinyl chloride resin, polyester resin, polyamide resin, polyurethane resin, polyether resin, and polycarbonate resin, One kind or a mixture of two or more kinds can be arbitrarily used.

[0009] In particular, polyolefin resin is preferable from the viewpoints of moldability, processability, price, stable supply, strength and the like, but the microbial decomposition rate of typical polyolefin resin in soil is ethylene-vinyl acetate. Polymer (EV
A)> Low density polyethylene (LDPE)> L-LDPE
Since (linear low-density polyethylene)> HDPE (high-density polyethylene)> PP, EVA or LDPE or a mixture thereof is particularly preferably used as the base polymer.

Examples of starch or its modified products include starches obtained from rice, corn, potato, sweet potato, wheat and the like,
Typical examples thereof include those obtained by grafting a polymerizable monomer such as styrene on the starch, and those coated with silicon.

As the organic metal compound, Fe, Al, N
At least one metal salt of a metal such as a, K, Ca, Mg, Zn, Mn, a metal oxide or a metal hydroxide is suitable, and particularly, the metal salt is an organic carboxylic acid such as a higher aliphatic carboxylic acid salt. Salt is preferably used.

The biodegradable plastic having such a composition has not only biodegradability by microorganisms but also photodegradability by which it is disintegrated and decomposed by receiving ultraviolet rays from sunlight.

In the present invention, the fertilizer coated with a biodegradable plastic obtained by blending a base polymer with at least starch or a modified product thereof and an organometallic compound is any fertilizer having a shape such as granular, spherical or cylindrical shape. And
There is no limitation on the type.

In addition to the above-mentioned base polymer, starch or its modified products and organometallic compounds, biodegradable plastics may contain plasticizers, colorants, fillers, etc. within a range that does not impair the effects of the present invention. One kind or two or more kinds of additives can be blended.

The resin-coated fertilizer of the present invention may have any shape, and may be formed into various shapes such as granular, spherical and fibrous shapes.

[0016]

In the present invention, since the coating material for coating the fertilizer is formed of the biodegradable plastic in which the base polymer is mixed with the starch or its modified product and the organometallic compound, as shown in FIG. It disintegrates and decomposes by a two-stage biodegradation mechanism.

The first stage biodegradation is mainly an action of starch. That is, starch has the property of being rapidly decomposed in a short period of time by amylase secreted from microorganisms in the soil, etc., and the starch particles having such properties are exposed to the surface by being scattered in the coating material. The starch is gradually decomposed inward by the microorganisms and disappears. Therefore, there is an effect that the surface of the base polymer is made porous to lower its mechanical strength and accelerate the disintegration of the polymer. In addition, the contact area with soil increases with the increase in surface area caused by microvoid formation, and the capillary phenomenon due to the presence of microvoids physically absorbs water in the soil to form a favorable environment for the survival of microorganisms. Therefore, it also attracts other microorganisms that may biodegrade the base polymer. However, starch itself does not directly contribute to the deterioration and decomposition of the base polymer.

The subsequent second stage biodegradation is mainly an action by organometallic compounds. That is, a metal salt such as Fe catalytically decomposes hydroperoxide generated in the initial stage of deterioration of the base polymer by a redox reaction,
It breaks the molecular chain of the base polymer and promotes biodegradation of the base polymer through lowering the molecular weight and making it hydrophilic. The oxidized base polymer is directly decomposed by the enzyme metabolism of microorganisms attracted to the surface of the base polymer by the action of starch in the above-mentioned first step, and finally decomposed into carbon dioxide gas and water to disappear. . Further, the organometallic compound has a remarkable increase in carbonyl due to ultraviolet rays, and therefore acts as a light absorber and also has an effect of promoting photodegradation of the base polymer.

[0019]

Example Modified starch 8.6 obtained by subjecting low-density polyethylene 84.6% to cornstarch silane coupling treatment.
%, Calcium oxide 1.6%, oxidized oil 1.2%, iron stearate 1.0%, aluminum hydroxide 1.0%,
A resin solution was prepared by mixing 1.0% aluminum sulfate and 1.0% oxidized wax, and the resin solution was introduced into the fertilizer particles in a jet stream from a nozzle to coat the fertilizer.

[0020]

INDUSTRIAL APPLICABILITY The resin-coated fertilizer of the present invention has a slow-acting effect, and after the fertilizer components are eluted, the coating material biodegrades substantially at the same time and disappears substantially. Therefore, foreign substances do not remain in the soil, and environmental pollution can be effectively prevented.

[Brief description of drawings]

FIG. 1 is a diagram outlining a biodegradation mechanism in a resin-coated fertilizer of the present invention.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Yoshito Otake 5877-11 Tomonuma, Nogi-cho, Shimotsuga-gun, Tochigi Prefecture (72) Inventor Yoshifumi Fujii 8-2-1 Ginza, Chuo-ku, Tokyo Takenaka Civil Engineering (72) ) Inventor Shoji Shimizu 2-5-5 Hitotsubashi, Chiyoda-ku, Tokyo Dainik Co., Ltd. Tokyo Head Office (72) Inventor Makoto Nishitani 4-15-107 Chuo, Soja City, Okayama Prefecture (72) Inventor Hitoshi Asabe Okayama Prefecture 2111-1 Chayamachi, Kurashiki City (72) Inventor Kiyoaki Okuda 8-21-1, Ginza, Chuo-ku, Tokyo Stock company Takenaka Corporation Tokyo Main Store (72) Innovator Shinnao Murakami 1 Otsuka, Inzai-cho, Inba-gun, Chiba Prefecture 5th Stock Co., Ltd. Takenaka Corporation Technical Research Institute

Claims (3)

[Claims] 1. A resin-coated fertilizer comprising a fertilizer coated with a biodegradable plastic obtained by blending a base polymer with at least starch or a modified product thereof and an organometallic compound. 2. The resin-coated fertilizer according to claim 1, wherein the base polymer is a polyolefin resin. 3. The resin-coated fertilizer according to claim 1, wherein the base polymer is an ethylene-vinyl acetate polymer, low-density polyethylene, or a mixture thereof.