JPS60103093A - Coating material for slow-effective fertilizer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating material for slow-release fertilizers, particularly water-soluble 11.
'), relates to a slow-release fertilizer coating material in which a curable aqueous solution consisting of molecules and glyoxal is combined with polyacrylic acid as a curing catalyst.

Slow-release fertilizers are fertilizers that are made to effectively and sustainably deliver the amount of fertilizer needed by plants over a long period of time in a single application by controlling the physical release of the fertilizer, and have recently become popular in gardening, etc. Used a lot. Using a coating material is one method for manufacturing such slow-release fertilizers.A coating material is applied to the outer surface of granular fertilizer to form a coating layer, and this coating layer prevents the physical elution of the fertilizer. When a slow-release pressure is achieved by providing a function to adjust the pressure, it is required to have a strength that can be absorbed by the turgor pressure due to water absorption of granular fertilizers, and also to have appropriate water permeability so as to be able to control elution. ing. For this reason, water-repellent substances have conventionally been used as madder covering materials, but materials containing water-soluble polymers as one component have never been used. this is,
Contrary to the fact that a slow-release coating material for lumber is required to have the above-mentioned properties, water-soluble polymers have the property of undergoing a cross-linking reaction even if a hardening agent is used. Even if it is coated with granular fertilizer as a covering material for slow-release fertilizer to form a coating layer, its strength will decrease due to swelling caused by water dripping in the soil during use, and the turgor pressure due to water absorption of the granular fertilizer will decrease. This is due to the fact that it is easily destroyed and cannot function as a slow-release fertilizer. In addition, water-repellent substances include polyolefins, waxes, etc., and some are used as coating materials for slow-release fertilizers to control fertilizer elution. Since the water-repellent substance remains in the form of lees, it is troublesome to remove it, reducing the product value.

The inventors of the present invention have conducted extensive research in order to resolve the drawbacks of coating materials for slow-release fertilizers that are mainly composed of water-soluble polymers and to develop coating materials for slow-release fertilizers that do not leave residue. By mixing a curable aqueous solution consisting of a water-soluble polymer and glyoxal with polyacrylic acid as a curing catalyst,
The present invention was completed after discovering that the coated feathers can be used as a coated feather for needles with excellent slow-release performance.

That is, in the present invention, when a water-soluble polymer and glyoxal undergo a crosslinking reaction through treatment such as heating, and a three-dimensional network-like mixed aqueous solution is used as a coating material for granular fertilizer, the elution of fertilizer:1 is controlled and t'J Based on the idea that water-soluble products
The compound that acts as an effective catalyst for the bridging reaction (11) is weakly acidic, the compound itself is water-soluble, has a -6 molecule size, and is compatible with the water-soluble polymer that is the main component (+11). From the viewpoint that it is important to have good curing properties, polyacrylic acid was selected from among the species // compounds as being effective as a curing agent, and it was used as a water-soluble The aqueous solution mixed with a hardened aqueous solution consisting of a polymer and GlyA-Kyzal is used as a coating material for slow-release fertilizer.

There are no particular restrictions on the water-soluble polymer of the present invention. In order to cure it by crosslinking with glyoxal, it is necessary to use a water-soluble polymer group, an ami-F group, an ami-tsuno group, etc., which have high reactivity with glyoxal. There are 8 bags that have functional properties, and typical examples include polyvinyl alcohol and its derivatives, polyacrylamide and its copolymers, starch and its derivatives, cellulose modified products, polyacrylamide and its copolymers. Examples include Hoffman decomposition products, polyethylene imine, etc., and for the purpose of making a coating material for slow-release fertilizer, the higher the content of functional groups, the more preferable it is, and it is desirable to contain at least 1 g equivalent per 1 kg of water-soluble polymer. The molecular weight is preferably such that the viscosity of a 10% by weight aqueous solution is 50 to 2000 CP for the performance and workability reasons.The mixing ratio of the water-soluble polymer and glyoxal is determined by the crosslinking between the functional group of the water-soluble polymer and glyoxal. In order to bring the reaction to completion or near completion, a ratio is selected such that the number of functional groups in the water-soluble polymer is equal to the number of functional groups in glyoxal. For example, for polyvinyl alcohol with a saponification degree of 89%, It is preferable that the weight ratio is 1 (10:50 to 80).

There are no particular restrictions on polyacrylic acid, but the degree of polymerization is 1O~
The mixing ratio of glyoxal to glyoxal is preferably 100.
It is preferable to use 2 to 20 parts by weight, and 2 to 20 parts by weight.
If the weight is less than 111%, the curing catalyst does not work well, and the degree of crosslinking between the water-soluble polymer and glyoxal cannot be increased, and it does not function as a slow-release fertilizer solution covering material. 1! do not have. 20 again! TL, f1
If it exceeds 1:1, a coating layer will form on the outer surface of the granular fertilizer, and when used as a slow-release fertilizer, this polyacrylic acid will elute, reducing the strength of the coating layer.
,! It is easily destroyed by the turgor pressure caused by water absorption of the material.

To apply the slow-release fertilizer coating material of the present invention to the granular fertilizer Fl, for example, an aqueous solution containing 1% of the active ingredients consisting of a water-soluble polymer, glyoxal and υ polyacrylic acid is transferred or flowed. It is done by spray painting on the oily manure I, '1 k: +! In order to maintain the strength of the coating layer, granular fertilizer [14% or more per weight] or 8 yellow is used, while too much 11j7. Since the leaching of the fertilizer is severely restricted and most of the applied fertilizer remains unleached, it must be kept at most 30% by weight or less. Usually 3~l Q? It is preferable to set it as %.

As explained above, the present invention uses a water-soluble polymer as a main component as a fitting material for slow-release fertilizer, and can appropriately mix inorganic fillers such as calcium carbonate and talc, and has slow-release performance. This makes it possible to further control the

Hereinafter, the present invention will be described in more detail using Examples, but these are only representative examples, and it goes without saying that the present invention is not limited to these examples. .

Example 1 a) Manufacturing method of coating material 5 parts of polyvinyl alcohol with a degree of saponification of 88% and a degree of polymerization of 1700, 8'r of a 40% by weight glyoxal aqueous solution
iB, 35-fold polyacrylic acid with a degree of polymerization of 20: f,
A Jt coating material was prepared by dissolving 1 part of ii% aqueous solution and 86 parts of water.

mouth)! Dynamic fertilizer production method + JEM 41 parts of ammonium, 28 parts of potassium sulfate, and 31 parts of ammonium phosphate are crushed using a hammer set pulverizer, 25 parts of water is added thereto, and the mixture is pulverized using a transfer granulator to a diameter of 5 to 10 mm. It was granulated into granules. Furthermore, spray the coating material on this granulated fertilizer so that the amount applied is 1 kg of fertilizer.
It was spread at a concentration of 50 g/g and dried at 150°C for 5 minutes to obtain a slow-release fertilizer. The dissolution rate of this fertilizer in water (fertilizer/water weight 1720) after 24 hours at 30°C was determined as A111 and as shown in Table 1.

For comparison, an aqueous solution without polyacrylic acid of Example 1 was prepared. When the granular fertilizer with Ik ¥04A was subjected to Jll+ determination in the same manner as in Example 1, all of the fertilizer was eluted.

Examples 2 to 6 The following various coating materials were used as slow-release fertilizers in the same manner as in Example 1, and the same 'Al11 constants were changed as shown in Table 1.

2) 10% aqueous polyacrylamide solution (
20°C sticky vessel 200CP) 60 copies, 40Φ'', I
, 'L% glyoxal aqueous solution 10 parts, polymerization degree 20
An aqueous solution prepared by combining 77 parts of 1 part of a 35% by weight aqueous solution of polyacrylic acid and 29 parts of water.

3) A small amount of oxidized starch aqueous solution (viscosity at 20 °C = 8 oocp) eo parts, 40] glyoxani) and 8 parts of an aqueous solution, 35 parts of polyacrylic acid with a degree of polymerization of 50.
An aqueous solution made by combining 4 g of 1 part of % heavy foot solution and 30 parts of water.

4) 6 parts of partially saponified polyvinyl alcohol with a degree of saponification of 88% and a degree of polymerization of 1000, 8 parts of a 40% by weight aqueous solution of G'1 Nooxal, 1 part of a 35% by weight aqueous solution of polyacrylic alcohol with a degree of polymerization of 50, and An aqueous solution prepared by dissolving 85 parts of water and combining 41 parts.

5) Hydroxyethylcellulose (Fujihetsuta Shin L15) aqueous solution (viscosity 400C at 20°C) with 5ffi mass%
P) 75 parts, 7 parts of 40% by weight glyoxal aqueous solution,
An aqueous solution containing 1 part of a 35% aqueous solution of polyacrylic acid having a degree of polymerization of 20 and Wood 17 a++.

6) 10% by weight acrylamide 80 parts/ac1 nitrile 20 parts copolymer aqueous solution (viscosity 150c at 20°C)
p) eo part, 8 parts of 40% by weight glyoxal aqueous solution, 1 part of polyacrylic # having a degree of polymerization of 50, and 31Δ1 of water (
An aqueous solution containing 41 parts of

Table 1 Fertilizer eluted in water Test method Warm melon 30’C Small sample 12.5g Waterwheel i1: 250g

Claims (1)

[Claims] A wave IJ feather for slow-release fertilizer characterized by mixing polyacrylic acid as a curing catalyst with a curable aqueous solution consisting of a water-soluble polymer and glyoxal.