JP2005341898A - High water-absorbing lightweight ridging containing water-repellent organic material and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an extremely lightweight ridging material having continuous water repellency preventing effect and excellent in preservability. <P>SOLUTION: A method for producing the ridging material comprises adding a powdery product of clay minerals of zeolite and bentonite, a binder becoming insoluble by heating and comprising e.g. polyvinyl alcohol and starch, and water to a water-repellent organic material of a lightweight material with bulk specific gravity of ≥0.25 such as peat moss, mixing the product, and heating and drying the product at an initial temperature of 70°C-150°C to bring water content to ≤10 wt.%. As a result, the clay minerals adhere to the surface of the organic material to improve water-absorbing properties and continuously prevent water repellency. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for improving the water repellency of a water-repellent organic material such as peat moss widely used as a soil material.

  In agricultural and horticultural seedling cultivation soil, organic materials and clay minerals with different properties are mixed in an appropriate ratio in order to provide water retention, air permeability, and fertilizer. Organic materials such as coconut dust and coconut dust have high water retention and air permeability, and are often used as soil cultivation materials. These soils are required to be lighter from the viewpoint of workability.

However, since the conventional soil has mixed materials with completely different bulk specific gravity, the dispersibility is poor, and the bulk specific gravity of the entire soil is limited to about 0.25.
In addition, it has been clarified that conventional soils are altered in about one month when stored at a moisture content of 25-30% by weight. If the water content is reduced in order to improve the storage stability of the culture medium, there is a problem that the water absorption at the time of sowing is reduced due to the water repellency of the organic material.

  For improving the water repellency of organic materials, various water repellency prevention methods or water repellency suppression methods have been proposed. For example, Patent Document 1 discloses a technique for treating peat moss with a surfactant. . Patent Document 2 discloses a technique in which an organic material is treated under reduced pressure, and a clayey material such as bentonite or a surfactant is placed in the internal space.

Further, Patent Document 3 discloses a method of forming a bentonite film on the surface of the peat moss by applying a fine bentonite powder of a water-absorbing clay material to the surface of the peat moss and then applying pressure. In the technique described in Patent Document 3, it is said that the water absorption rate of peat moss can be improved from 0.2 ml / min to about 4 ml / min when the moisture content is 0%.
JP-A-10-164975 JP-A-11-266694 Japanese Patent No. 3389017

However, the method using a surfactant has a problem that water repellency becomes stronger with time and water absorption decreases again due to evaporation of water due to storage and a decrease in water repellency prevention ability of the surfactant. In addition, the techniques described in Patent Document 2 and Patent Document 3 have a drawback that a processing apparatus becomes large because processing under reduced pressure or under pressure is required.
An object of the present invention is to provide an ultralight soil-building material that has a continuous water-repellent effect and is excellent in storage stability. It is another object of the present invention to provide a method for preventing water repellency of a water repellent organic material without using a surfactant or the like, and producing a super lightweight soil cultivating material having high water absorption.

The manufacturing method of the superabsorbent and light weight soil of the present invention that solves the above problems is to add a water-repellent organic material, a clay mineral powder, a binder made of a water-soluble polymer material that is insolubilized by heating, and water, and mix, It is characterized by heat drying at a product temperature of 70 ° C. or higher and 150 ° C. or lower until the water content becomes 10% by weight or less.
In the manufacturing method of the superabsorbent lightweight soil of this invention, the process of adding a fertilizer can be included either before and after heat drying, and it is also possible to perform granulation at the time of heat drying.
The highly water-absorbing light weight soil of the present invention is manufactured by the above manufacturing method.

Hereafter, the manufacturing method of the superabsorbent lightweight soil of this invention is explained in full detail.
Specifically, the method for producing the superabsorbent lightweight soil of the present invention is mainly made of water-repellent organic materials such as peat moss, coconut husk pulverized product (husk dust, coir dust, coconut dust called cocochips, etc.), In particular, a lightweight material having a bulk specific gravity of 0.25 or less at a moisture content of 0% is used as a main raw material. These lightweight materials are generally used as horticultural materials, but have high water repellency and are rarely used alone as soil. The production method of the present invention can also be applied as a water repellent prevention treatment method for the main raw material, and the light-weight material after the water repellent prevention treatment can be used alone as a soil.

  Clay minerals mixed with organic materials are zeolite, bentonite, kaolinite, volcanic ash soil, akadama soil, and Kanuma soil. Clay minerals containing ~ 0.3 mm powder are preferred. By using a powdery material having a particle size of 1 mm or less, a uniform clay mineral film is formed on the surface of the organic material, water repellency of the organic material can be prevented, and the water absorption of the obtained soil can be improved. The blending ratio of the organic material and the clay mineral varies depending on the type of the organic material, but is in the range of 1: 0.2 to 5, preferably 1: 0.5 to 2. By adjusting the blending ratio of the clay mineral, the bulk specific gravity of the obtained soil can be adjusted.

  The binder is made of a water-soluble polymer material (self-crosslinkable polymer material) that is insolubilized by heating. Specifically, polyvinyl alcohol, carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, polyacrylamide, polyacrylic acid, starch, etc. A well-known binder can be used 1 type or in mixture of 2 or more types. Of these, polyvinyl alcohol is preferable, and particularly, partially saponified polyvinyl alcohol having a polymerization degree of 200 or more, preferably 400 to 2000, and a saponification degree of 70 to 99 mol%, preferably 80 to 90 mol% is preferable. In addition, when natural products such as starch and starch are used, the soil can be made of 100% natural material.

  Such a self-crosslinkable polymer material is used as a molding aid for granulation. In the present invention, by mixing with the above-mentioned water-repellent organic material and clay mineral, An unexpected effect of adhering a mineral to the surface of an organic material, improving water absorption, and continuously preventing water repellency was obtained. Moreover, when mixing an organic material and a clay mineral, the fall of the dispersibility resulting from the difference in bulk specific gravity can be prevented, and a dispersibility can be improved. In addition, it functions as a binder when granulating the entire soil material including water-repellent organic materials, clay minerals, and fertilizer added as needed, and it can produce a soil that is super lightweight and has excellent properties. .

  The addition amount of the self-crosslinking polymer material is in the range of 1: 0.005 to 0.5, preferably 1: 0.01 to 0.3 with respect to the organic material. By adding in such a range, the continuous water-repellent prevention effect can be acquired, without inhibiting the growth of a plant.

The method for preventing water repellency of the present invention is to blend the above-mentioned organic material, clay mineral and polymer material in appropriate blending amounts, add water and mix, and then 70 to 150 ° C. as the product temperature, preferably 100 to It is dried to a water content of 10% by weight or less while heating to 120 ° C. The amount of water added to the material or the like varies depending on the amount of water contained in the material itself, but when the total amount of organic material, clay mineral and polymer material is 1, it is added about 0.5 to 3 times.
By adding water and mixing, the water-soluble polymer material functions as a binder, and the clay mineral adheres to the surface of the organic material. It is considered to be a material that does not easily change.

  The time for the drying treatment is not particularly limited, but the drying is performed so that the water content is 10% by weight or less, preferably 5% by weight or less. By controlling the water content to 10% by weight or less, it is possible to suppress the propagation of various bacteria during storage of the soil and to prevent alteration due to microbial activity.

According to the method for producing soil according to the present invention (water repellent prevention treatment method), the organic material is simply mixed with a clay mineral, a polymer material and water and heated and dried. You can get large, high quality soil material. Specifically, it is possible to obtain a water repellency preventing effect having a bulk specific gravity of 0.1 to 0.4 and a water absorption speed of 5 ml / min or more when the water content is less than 10% by weight.
In addition, in the method for producing soil according to the present invention, after mixing necessary materials, granulated to a desired particle size and then dried by heating, a granular soil can be obtained.

  The culture medium of the present invention is produced by the above production method, and fertilizer components such as ammonium sulfate, urea, phosphoric acid, potassium chloride, and superphosphate lime can be blended as necessary. The fertilizer component may be blended prior to the drying step or may be blended after drying, but by mixing prior to the drying step or granulation step, the fertilizer component can be uniformly dispersed in the cultivation soil. it can. The amount of fertilizer added is not particularly limited, but is usually 0.05 to 2.0% by weight, preferably 0.1 to 1.0% by weight of the soil.

  The culture soil of the present invention can be further blended with materials such as granular zeolite, pearlite, vermiculite, rock wool, etc., depending on the application, and can be used as horticultural seedling culture soil, greening material and the like.

  Examples of the present invention will be described below.

[Example 1 and Comparative Examples 1 to 3]
Table 1 shows coconut dust (trade name: coconut husk dust, manufactured in the Philippines), zeolite (average particle size of 1 mm or less), partially saponified polyvinyl alcohol (degree of saponification: 88 mol%, degree of polymerization: 500) and water. After blending and mixing at a ratio, it was dried at about 100 ° C. until the water content became 0%. About the material after drying, the bulk specific gravity, the water absorption speed, and the water transmission speed were measured, respectively. The water absorption rate is as follows. Place the dried material in a 100 ml cylindrical container (diameter: about 5 cm x height: about 5 cm) with a water permeation filter at the bottom. While maintaining, the amount (ml) of water absorbed per minute was measured. The water permeation rate was determined by saturating the cylinder after measuring the water absorption rate with water and measuring the amount of water (ml / min) passing through the bottom of the cylinder while maintaining the water level 2.5 cm above the cylinder. The results are shown in Table 1.

[Comparative Example 4]
Into the same coconut dust and zeolite as in the examples, a surfactant (trade name: Aqua Glow 2000L, nonionic) and water are blended and mixed in the proportions shown in Table 1 until the water content becomes 0% at about 100 ° C. Dried. About the material after drying, the bulk specific gravity, the water absorption speed, and the water transmission speed were measured, respectively. The results are shown in Table 1.

  As can be seen from the results shown in Table 1, the material of Example 1 in which the four components of zeolite, coconut dust, polyvinyl alcohol and water were blended had a light bulk specific gravity and an excellent water absorption rate and water transmission rate. On the other hand, when only zeolite and coconut dust were mixed and dried (Comparative Example 1), the bulk specific gravity was slightly heavy, and the water absorption rate and water permeability rate were not good. This seems to be because the powdery zeolite present in the coconut dust formed a wall and hindered water absorption. When water was added to that of Comparative Example 1 (Comparative Example 2), the bulk specific gravity, the water absorption rate, and the water transmission rate were improved, but were lower than those of Example 1, and the water transmission rate was particularly insufficient. . In the case where no zeolite was contained (Comparative Example 3), the bulk specific gravity was very light at 0.1 because no zeolite having a high bulk specific gravity was added, but the water absorption rate was poor and water repellent.

In Comparative Example 4 in which a surfactant was added without using polyvinyl alcohol, an excellent water absorption rate was obtained, but the bulk specific gravity was slightly heavy.
For Examples 1 and Comparative Example 4, the change in water absorption rate over time was further observed. The results are shown in Table 2.

  As can be seen from the results in Table 2, the water absorption rate of the material of Example 1 does not change even after 1 month, whereas the water absorption rate of the material of Comparative Example 4 using a surfactant is 1 month later. Reduced to less than half.

[Examples 2 to 4]
Other than that, the water repellent prevention treatment was performed in the same manner as in Example 1 except that the kind of organic material and the mixing ratio were changed, and the bulk specific gravity, water absorption rate, and water permeation rate of the treated material were measured. The results are shown in Table 3.
[Example 5]
The same organic material as in Example 3 was used at the same blending ratio, only the drying temperature was varied, water repellent prevention treatment was performed, and the bulk specific gravity, water absorption rate and water permeation rate of the treated material were measured. The results are shown in Table 3.

  As can be seen from the results shown in Table 3, even when the type and blending ratio of the organic material are changed, by appropriately adjusting the amount of the binder and water, it is excellent in water absorption as in Example 1 and has a small bulk specific gravity. The material was obtained. However, when the drying temperature was low, the water repellency was not sufficiently improved.

[Example 6]
The same organic material as in Example 1 was used at the same blending ratio, and the water repellent prevention treatment was performed by changing the moisture content during drying to 0 to 40%. After storing the obtained soil in an environment of 20 to 30 ° C. for one month, the number of aerobic bacteria (Bacteria) and fungi was simply measured with an agar medium (trade name: Biochecker). As a result, when the water content of the medium exceeded 10% as shown in Table 4, rapid growth of mold was observed.

According to the present invention, water repellency of water repellent organic materials such as peat moss and coconut dust can be prevented by a simple process, and a super light weight soil having high water absorption and water repellency can be prevented for a long time. be able to.

Claims (7)

  A method for producing a highly water-absorbing lightweight soil containing a water-repellent organic material, wherein a clay mineral powder, a binder made of a water-soluble polymer material that is insolubilized by heating, and water are added to the water-repellent organic material and mixed. And a method of heating and drying at a temperature of 70 ° C. or higher and 150 ° C. or lower until the water content becomes 10% by weight or less.   The manufacturing method according to claim 1, wherein the organic material is a lightweight material having a bulk specific gravity of 0.25 or less.   The method according to claim 1 or 2, wherein the clay mineral is one or a mixture of two or more selected from zeolite, bentonite, kaolinite, and volcanic ash.   The binder is one or a mixture of two or more selected from polyvinyl alcohol, carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, polyacrylamide, acrylic resin and starch. The production method according to item.   The manufacturing method according to any one of claims 1 to 4, further comprising a step of adding a fertilizer before or after the heat drying.   6. The production method according to claim 1, wherein granulation is performed during the heat drying. A superabsorbent and lightweight soil produced by the production method according to claim 1.