JP2002363562A - Granular water-retentive agent for soil conditioning - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a granular water-retentive agent for soil conditioning, which comprises a base material and a water-soluble cellulose ether, an has a particle size such that 10-80 wt.% of the granules pass through a 3.5-mesh sieve (sieve opening: 5.6 mm) as described in JIS Z8801. SOLUTION: When the granular water-retentive agent for soil conditioning is spreaded on a place where an improved water retention is desired, the granules are not dispersed by wind because they contains a less amount of fine powder. Once these granules absorb water by rain or irrigation water, they are caked with each other to become solid and form a water-retentive layer so that they are hard to be dispersed. Therefore, the granular water- retentive agent does not produce a water-content irregularity, even if it is applied onto a sandy soil. Where it is applied onto a sandy soil having some water-retentive force or a place where the soil gets a water-retentive force and become viscous, the agent does not cause reduction of gas phace, which is disadvantageous for plant growth.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a granular water reserving agent for soil improvement which is suitably used as a soil modifying agent for desert areas having low water retention and soil for livestock.

[0002]

2. Description of the Related Art One-third to one-quarter of the earth's land area is desert or semi-desert, and it is reported that desertification is progressing at a speed of 60,000 km ² every year. ("Biotechnology to Save the Earth" by Masaki Takatsuji,
Published by Ohmsha). The application of a water-absorbing polymer has been mentioned as one of the soil modifying agents that solve this desertification. This scatters water-absorbing polymer particles in the sand,
Spraying in sand dunes or deserts allows the water-absorbing polymer to retain water, thus saving irrigation water.
At this time, if the water-absorbing polymer water retention agent is successfully attached to the roots of the transplanted seedlings, it is advantageous to bind the roots to the desert area. However, particularly in the case of a fine water-absorbing polymer, there has been a problem that the influence of wind at the time of application promotes the occurrence of uneven water content in sand.

Further, if this water-absorbing polymer is applied to a clayey soil having a certain water-retaining capacity, the water-absorbing liquid phase increases due to the addition, but the water-absorbing polymer expands and the gas phase decreases. There was a problem. The reduced gas phase is disadvantageous for plant growth and does not make sense for the original application. There is also a report that the addition of a large amount of water-absorbing polymer to clayey soil actually worsened the growth ("Biotechnology to Save the Earth" by Masaki Takatsuji, published by Ohmsha).

The present invention has been made in view of the above circumstances, and does not cause uneven water even when applied to a sandy ground, and is applied to a sandy ground having a little water-holding power or to a portion which has a water-holding power and has become a viscous soil. An object of the present invention is to provide a granular water retention agent for soil improvement, which does not cause a decrease in gas phase which is disadvantageous for plant growth even if done.

[0005]

Means for Solving the Problems and Embodiments of the Invention The present inventors have conducted intensive studies in order to achieve the above object, and as a result, have found a granular soil improvement water retention agent containing a base material and a water-soluble cellulose ether. And 2. described in JIS Z8801.
5 mesh (5.6 mm mesh) sieve pass is 10 to 80
When a soil improvement water retention agent having a particle size of 1% by weight is sprayed on the place where the water retention is to be improved as described above, the fine particles are small, so that the granules are not separated by the wind, and these are once exposed to rain or irrigation water. It has been found that when the granules absorb water, the granules adhere to each other to form a solid, form a single water-retaining layer, and can be used as a water-retention improving agent that is difficult to separate. Furthermore, by adding agar powder that is slightly less swellable in water, although not as much as a water-absorbing polymer, it is possible to improve water absorption, and furthermore, it is possible to add organic materials to be used as waste materials to the granules. As a result, the present invention has been completed.

Hereinafter, the present invention will be described in more detail.
The granular water-retaining agent for soil improvement of the present invention is a granular water-retaining agent for soil improvement containing a base material and a water-soluble cellulose ether, and is a 3.5 mesh (5.6 mm opening) sieve pass described in JIS Z8801. Has a particle diameter of 10 to 80% by weight.

[0007] Here, the above-mentioned base material includes water-absorbing inorganic minerals such as zeolite and bentonite and water-absorbing polymers, as well as cellulose substrates such as wood flour, pulp, sawdust and linter, and protein component substrates such as okara and soybean. And the like, especially organic wastes, and among them, bentonite is preferable.

As the bentonite, any of a sodium type and a calcium type can be used. Calcium type has good water absorption but poor cohesion, whereas sodium type has poor water absorption but good adhesion, but the granules produced in the present invention are not so affected by the type of bentonite. , Any of which can be used. Also,
It is also possible to prepare granules in the calcium form of bentonite, put sodium carbonate powder in the formulation, and make it absorb well at the beginning so that calcium can be replaced by sodium before use. The particle size is JIS Z
Using a standard sieve No. 100 (aperture 150 μm) specified in 8801, 100 g of cellulose ether powder was shaken with a Kansai Wire Mesh 429 type low tap sieve shaker at a shaking number of 20.
After shaking for 30 minutes under the conditions of 0 strokes / min, 15.6 strokes / min, and a shaking width of 50 mm, the residue on the sieve was 50% by weight.
It is desirable to use the following.

On the other hand, examples of the cellulose ether include alkyl cellulose, hydroxyalkyl cellulose, hydroxyalkyl alkyl cellulose, carboxymethyl cellulose and the like. For example, water-soluble methyl cellulose (MC) having 10 to 40% by weight of methoxyl group is used. Alkylcellulose, hydroxypropylmethylcellulose (HPMC) or hydroxyethylmethylcellulose (HEMC), ethoxyl containing 10 to 40% by weight of methoxyl group and 3 to 30% by weight of hydroxyalkyl group for improving solubility. 5 to 20% by weight of the group and 10 to 45% of the hydroxyethyl group.
% By weight of hydroxyethylethylcellulose (HEE
Hydroxyalkylalkylcellulose such as C),
Furthermore, hydroxypropylcellulose (HPC) having a hydroxypropoxyl substitution degree of 40 to 70% by weight, hydroxyethylcellulose (HEC) having a hydroxyethoxyl substitution degree of 30 to 70% by weight, carboxymethyl group 1
Examples include, but are not limited to, sodium carboxymethylcellulose (CMC-Na) in an amount of up to 30% by weight, and any cellulose ether which has been made water-soluble by etherifying cellulose can be used. The degree of substitution is described in J. G. FIG. Google
r, E. P. Samsel, and G .; H. Beab
er, Talanta, 9, 474 (1962).

[0010] The particle size of these cellulose ethers is determined by using a standard sieve No. 100 (aperture size: 150 µm) defined by JIS Z8801, and using a 429 type low tap sieve shaker manufactured by Kansai Wire Mesh Co., Ltd. to shake 100 g of cellulose ether powder. 200 strokes / min, 15.6 shots /
After shaking for 30 minutes at a shaking width of 50 mm for 30 minutes, it is desirable to use a material having a residue on the sieve of 30% by weight or less in order to make the solubility at the time of preparing the granules appropriate.

[0011] The molecular weight of the cellulose ether used in the present invention is not particularly limited.
As a corresponding value, in a Ubbelohde viscometer specified in JIS K2283-1993, a value of 100 mP was measured at 20 ° C. of a 2% by weight aqueous solution.
It is appropriate to use one having at least a · s, preferably at least 80,000 mPa · s in order to obtain a water retention capacity and a caking power of granules. The upper limit is usually 300,000 m
Pa · s or less, but is not limited thereto.

The production of the cellulose ether used in the present invention is not particularly limited.
It can also be produced using a linter material obtained from high molecular weight cotton as described in JP-A-19115.

In the present invention, it may be advantageous to further add agar powder to prepare granules. This is because the agar powder swells slightly when exposed to warm water of about 30 to 40 ° C. as seen in tap water in summer, and generates a cohesive force in a situation where it is partially dissolved around this temperature. Granules prepared only with base materials such as cellulose ethers and bentonite have a dense property, and even if water does not easily penetrate, the swelling of water is improved by slight swelling and uniform water retention This is because the base material and the cellulose ether are easily exerted.

As the agar used in the present invention, as a raw material, red algae such as Amakusa, Ogonori, Obakusa, Itakusa and the like are washed with water, immersed in water, and boiled at 80 to 90 ° C.
After removing impurities by filtration, coagulation, dehydration, heating or freeze-drying, and pulverization of agar powder can be used. It is known that the properties of agar vary depending on the composition ratio of the components agarose and agaropectin, such as the heat solubility after dispersion in water and the strength of the gel due to cooling of the dissolved liquid, but all can be used in the present invention. It is. An important characteristic of the agar powder used in the present invention is that the powder swells when exposed to water at about 30 to 40 ° C., and generates a cohesive force in a situation where the powder is partially dissolved at around this temperature. It is in. Any agar powder can be used to exhibit this performance. The particle size of the particles exhibiting good swelling properties is determined by using a standard sieve No. 100 (aperture size: 150 μm) specified by JIS Z8801 and agar powder 100 using a 429 type low tap sieve shaker manufactured by Kansai Wire Mesh Co., Ltd.
g at a shaking rate of 200 times / min, a number of strokes of 15.6 times / min, and a shaking width of 50 mm for 30 minutes, and then use a substance whose residue on a sieve is 50% by weight or less at the time of granule preparation. Is desirable from the viewpoint of dissolving and expressing caking force.

Regarding the molecular weight of agar, the viscosity of a 1.5% by weight aqueous solution measured at 80 ° C. with an Ubbelohde viscometer as in the case of cellulose ether is 5 to 100 m.
Pa · s, particularly preferably 10 to 50 mPa · s.

In the present invention, the content of the base material and the cellulose ether in the granular water retention agent is 20 to 90% by weight, particularly 30 to 80% by weight, and the content of the cellulose ether is 10 to 90% by weight.
The content is preferably from 80 to 80% by weight, particularly preferably from 15 to 60% by weight. With only the base material, the cohesive force is insufficient and granulation is difficult, and with the cellulose ether alone, the water absorption and water retention are insufficient. As described above, bentonite is preferable as the base material, and 30 to 100% by weight, particularly
It is preferred that 0 to 100% by weight be bentonite. Furthermore, a water-insoluble organic material as a base material may be useful as a plant fertilizer component. In this case, the ratio of the organic material to the base material is not particularly defined, but is 60% by weight.
It is preferable that the amount is not more than the following in order to maintain the effects of the present invention.

The amount of agar used is preferably 5 to 50% by weight of the agar powder in the granular water retention agent as an amount capable of imparting swelling properties.

The method for producing the particulate water retention agent of the present invention is not particularly limited, but water is added to a composition comprising the above components,
Generally, a method of kneading and extrusion molding, or a method of dispersing the composition in an air stream, adding water to form particles, and drying to form particles are used. Regarding the shape of the finished granules, it is difficult to spray if the size is too large, and it is easy to scatter when spraying if the amount of the fine powder is too large. Therefore, 3.5 of JIS Z8801 is described.
It is necessary that the mesh (5.6 mm opening) sieve pass has a particle size of 10 to 80% by weight, particularly 20 to 70% by weight. The remaining portion (3.5-mesh sieve on) is preferably a sieve pass with an opening of 11.2 mm.

The water retention agent obtained by the present invention can be used for improving the water retention of desert areas as described above. In addition, the water retention agent can also be used to improve the soil quality of horse racetracks, the soil of livestock animals, and the soil of poultry farms. It can also be used for

[0020]

When the granular water-retaining agent for soil improvement of the present invention is applied to a place where the water retention is to be improved, the fine particles are small, so that the granules are not separated by the wind, and these granules are once dispersed by rain or irrigation water. When water is absorbed, the granules adhere to each other and become solid, forming one water retention layer, which is difficult to separate,
The soil-improving granular water retention agent of the present invention does not cause uneven water even when applied to sandy soil, and is applied to a sandy ground having some water holding power or a portion that has obtained water holding power and becomes a viscous soil. It does not cause a decrease in the gas phase that is disadvantageous for growth.

[0021]

EXAMPLES The present invention will be described below in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. Incidentally,% in the table indicates% by weight.

[Examples and Comparative Examples] <Preparation of granules for soil improvement> J having an aperture of 150 μm
According to the No. 100 sieve described in IS Z8801, the powder on the sieve measured under the above-described conditions has a value shown in Table 1, and a methoxyl group, hydroxypropoxyl group, hydroxyethyl group
The ethoxyl group and the carboxymethyl group are the values shown in Table 1, and the measured viscosity of a 2% by weight aqueous solution at 20 ° C. in an Ubbelohde viscometer specified in JIS K2283-1993 is shown in Table 1; It was evaluated by the same sieve and was evaluated according to JIS K2283-19
Soil improvement by the following production method using agar having the viscosity measured at 80 ° C. of a 1.5% by weight aqueous solution at 80 ° C. with an Ubbelohde viscometer specified in 93 and the formulation shown in Table 1 Granules (water retention agent) were prepared.

The cellulose ether shown in Table 1, wood flour, bentonite, and sodium carbonate as an activator of bentonite were added, and materials other than water were mixed for 30 seconds with a mixer blade of 1,000 rpm using a 20-liter super mixer manufactured by Kawada Seisakusho. After stirring, a predetermined amount of water shown in Table 1 was added, and the mixture was further stirred at the same stirring speed for 30 seconds, and then the mixed material was discharged. The discharged material was granulated with a 3 mm screen using an RG8-2 cylindrical extrusion granulator manufactured by Kikusui Seisakusho. The granulated product was dried at 80 ° C. for 8 hours in a blowing oven DN83 manufactured by Yamato Scientific Co., Ltd. to prepare a soil improving granule.

<Evaluation of soil improvement granules>
m, a 20-cm deep 500-ml transparent plastic ball, spread JIS silica sand No. 5 with a thickness of 10 cm, put the granules on it with a thickness of 5 cm, add water as artificial rain with a 300-ml agricultural watering can, 30 after addition
After a few seconds, I tried to find out whether or not the particles absorbed and solidified due to water absorption. The case where the solidification was sufficient to be taken out as a lump was evaluated as "O", and the case where the solidification was not enough to be taken out as a lump was evaluated as "X". Furthermore, the sand surface under the removed fixed matter was observed, and when water did not reach the sand surface, the water retention rating was "○", when water reached the bottom of the ball along the sand surface. Was evaluated as water retention “x”.
Further, the solidified mass was dried in an oven at 80 ° C. for 12 hours, and when the moisture was held at 20% by weight or more, the drying resistance was “○”, and when it was less than 20% by weight, the drying resistance was “X”. Was evaluated. Next, once dried and solidified in an oven for an additional 12 hours, put again in a bowl and add water for 1 hour.
The mixture was sprayed with a 00 ml watering can and tested to see if water penetrated to the bottom of the sand. The case where water did not permeate was evaluated as re-water retentivity “、”, and the case where water permeated was evaluated as re-water retentivity “×”.

<Results of Performance Evaluation Test> As shown in the results of Examples and Comparative Examples shown in Table 1, according to the present invention, a soil exhibiting excellent fixation stability after spraying and exhibiting excellent water retention and drying resistance. It can be seen that an improved water retention agent is obtained.

[0026]

[Table 1] Wood flour: Ace International Inc.
Douglasfir wood floor
80 mesh sieve on 1% by weight, 200 mesh sieve on 2
5% by weight Bentonite: Kunimine Industry Co., Ltd., Kunibond Sodium carbonate: Wako Pure Chemical Co., Ltd., first grade reagent Cellulose ether: Shin-Etsu Chemical Co., Ltd. Agar powder: Ina Food Industry Co., Ltd., Ultra Agar AX −
30 100 mesh sieve on 20% by weight water-absorbing polymer: Diamond Wet A manufactured by Mitsubishi Rayon Co., Ltd.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) // C09K 101: 00 C09K 101: 00

Claims (6)

[Claims] 1. A granular soil improving water retention agent comprising a base material and a water-soluble cellulose ether, comprising JIS Z880.
3. A soil improving water retaining agent, wherein the 3.5 mesh (mesh 5.6 mm) sieve pass according to 1 has a particle diameter of 10 to 80% by weight. 2. The soil improvement water retention agent according to claim 1, further comprising a water-insoluble organic material. 3. The soil-improving water retention agent according to claim 1, further comprising an agar powder. 4. The soil improvement water retention agent according to claim 1, wherein the base material is bentonite. 5. The water retention agent for soil improvement according to claim 1, wherein the water-soluble cellulose ether is an alkyl cellulose, a hydroxyalkyl cellulose, a hydroxyalkylalkyl cellulose, or a carboxymethyl cellulose. . 6. The water-soluble cellulose ether according to JIS
Ubbelohde viscometer No. K2283-1993. 5
At a viscosity of 80% of a 2% by weight aqueous solution at 20 ° C.
The soil improvement water retention agent according to any one of claims 1 to 5, which has a water resistance of 000 mPa · s or more.