JP5403030B2 - Seed coating agent, seed coating agent - Google Patents

Description

  The present invention relates to an iron powder for seed coating suitable for seed coating such as rice seed, an iron powder coated seed obtained by coating the seed with the iron powder for seed coating, a seed coating agent, and a seed coating agent. Seed coating agent-coated seeds.

Along with the aging of farmers and the globalization of agricultural product distribution, labor saving in agricultural work and reduction in agricultural production costs are issues to be solved. In order to solve these problems, for example, in paddy rice cultivation, a direct sowing method in which seeds are directly sown in a field is becoming widespread for the purpose of eliminating the trouble of raising seedlings and transplanting. Among them, in order to increase the specific gravity of seeds, a technique using seeds coated with iron powder has been attracting attention because of its merit of preventing floating and outflow of seeds in paddy fields and preventing bird damage.
In addition, it is also noted that a sterilizing effect can be obtained as a secondary effect by iron powder coating.

  In order to utilize the direct sowing cultivation method using the seed coated with iron powder, it is required that the iron powder film coated in the process of transportation or sowing is difficult to peel off. When the iron powder coating peels, the specific gravity of the seeds decreases and the above-mentioned merit is not obtained, and the peeled coating causes clogging of the piping and biting into the rotation mechanism part in the transportation and seeding processes. This is because the peeled fine iron powder can cause dust. For this reason, peeling of the iron powder coating must be suppressed as much as possible.

As a technique for attaching and solidifying iron powder on the surface of rice seeds, Patent Document 1 proposes the following technique as a method for producing iron powder-coated rice seeds.
“To the rice seeds, iron powder, and 0.5-2% by weight of sulfate (excluding calcium sulfate) and / or chloride in a mass ratio to the iron powder, and further granulated by adding water, A method for producing iron powder-coated rice seeds, characterized in that iron powder is attached to solidified rice seeds by rust generated by oxidation reaction of metallic iron powder by supplying water and oxygen, and then dried. (See claim 1 of Patent Document 1)

  In the invention described in Patent Document 1, since the rice seeds are sown using a power spreader or a seeder, strength characteristics that do not collapse due to mechanical impact are necessary. The coating disintegration degree is measured by a method of measuring the degree of coating disintegration (hereinafter referred to as coating disintegration test), that is, a method of dropping a steel sheet having a thickness of 1.3 m to a steel plate with a thickness of 3 mm and giving a mechanical impact. It has been confirmed that practical strength is obtained.

  In Patent Document 1, no particular attention is paid to the iron powder particle size distribution. However, when iron powder having the particle size distribution shown in Table 1 below is used for coating, the iron powder-coated rice seeds described above are used. In the disintegration test, it is said that practical impact strength can be maintained.

Japanese Patent No. 44441645

Regarding the adhesion strength of the iron powder coating, Patent Document 1 discusses the collapse of the iron powder coating due to the impact caused by the drop in the seeding process. Therefore, as a strength test, a disintegration test is performed in which a mechanical impact is applied by dropping the steel sheet 5 times from a height of 1.3 m to a steel plate having a thickness of 3 mm.
However, rice seeds are subjected to mechanical external force not only in the sowing process but also in the transport process, as described above. And the mechanical external force which a rice seed receives in a transportation process is the frictional force of the sliding and rolling which arise between seeds or between a seed and a container other than the impact by fall.

When receiving an impact due to dropping, the iron powder coating is peeled off by cracking, but when receiving a frictional force, it is gradually peeled off by abrasion.
Therefore, in order to prevent the iron powder coating from peeling off not only in the seeding process but also in the transportation process, a coating having strength against frictional force is required.
However, there has been no technology for realizing iron powder that can cover rice seeds with sufficient strength against sliding and rolling frictional stress of seeds or seeds coated with iron powder.

In addition, as shown in Table 1, the particle size distribution of the iron powder described in Patent Document 1 is disclosed only when the proportion of the fine particle size of 45 μm or less is as large as 85% or as small as less than 35%. ing.
However, when iron powder containing a large amount of fine iron powder is used, iron powder reacts rapidly with oxygen in the air, and the seed coated with iron powder may be damaged by heat generation, There is also a concern of causing a fire when handling large quantities. In addition, since fine iron powder tends to generate dust, there is a problem that it is difficult to maintain a clean working environment.
On the other hand, if the content of fine iron powder is too small and the content of coarse iron powder is too large, the number of particles for coating the iron powder surface will be insufficient, making it impossible to form a uniform film. As a result, the film strength may be reduced.

Patent Document 1 discloses that a binder is added to enhance the adhesion of iron powder to rice seeds, and sulfate and / or chloride is added as a binder, and water is further added. And granulate. As a specific granulation method, iron powder, sulfate and / or chloride, and rice seed are put into a rotating container, and the surface of the rice seed is coated with iron powder and gypsum while spraying water. ing.
However, when the above granulation method disclosed in Patent Document 1 is used, aggregated particles of iron powder and a binder are likely to be generated.
Agglomerated particles are extremely harmful because they cause a decrease in the yield of adhesion of iron powder to rice seeds, and also cause various problems such as hindering the uniformity of coating components and reducing coating workability. is there.

The present invention has been made to solve such a problem, and coated with the seed coating iron powder and the seed coating iron powder capable of realizing a coating with less dropping of the iron powder not only in the sowing process but also in the transport process. The purpose is to obtain iron powder coated seeds.
Another object of the present invention is to obtain a rice seed coating iron powder that is less likely to damage rice seeds and is easy to handle and an iron powder coated rice seed coated with the rice seed coating iron powder. .
Another object of the present invention is to obtain a seed coating agent capable of realizing a coating with less iron powder dropping not only in a sowing step but also in a transportation step, and a seed coating agent-coated seed coated with the seed coating agent.
Another object of the present invention is to obtain a seed coating agent that is less likely to damage rice seeds and that is easy to handle and a seed coating agent-coated rice seed coated with the seed coating agent.

In order to solve the above problems, the inventor conducted the following studies on each of the iron powder and the binder.
<Examination of iron powder>
The inventor observed the surface of the rice seed and examined what kind of iron powder was effective in preventing peeling.
The inventor has focused on the surface structure of rice seeds. FIG. 1 is a secondary electron image of a rice seed pod by a scanning electron microscope. FIG. 1 (a) is an overall image, FIG. 1 (b) is a partially enlarged photograph, and FIG. 1 (c) is a further enlarged photograph. Is shown.
As can be seen from the photograph in FIG. 1, the surface of the rice husk, which is the outermost shell of the rice seed pod, has fine irregularities, and iron powder enters and adheres to the depressions in the irregularities, thereby forming a stronger coating. I thought it could be formed.
Then, when the iron powder particle diameter which can enter and adhere to the fine recessed part of a seed surface was examined, the knowledge that it was preferable to contain a predetermined amount of iron powder with a particle diameter of 45 micrometers or less was acquired.
However, if a large amount of iron powder having a fine particle size is included, the above-described heat generation and working environment problems occur, so it is also necessary that the amount be less than a predetermined amount.

Next, the inventors focused on the state of the surface of rice seeds. As shown in FIG. 2, hair 5 grows on the surface of rice husk 3 which is the outermost shell of rice seed pod 1.
As shown on page 21 of “Seeing the Microscopic Structure of Rice (by Takamasa Mezaki)”, the way the hairs 5 grow is also dense. Especially the space | interval of the hair 5 in the site | part where the hair 5 was crowded is 50-150 micrometers.
When the inventor coats the iron powder on the seed vat 1, the iron powder disposed between the hairs 5 by the elastic action of the hairs 5 is applied to the hairs 5 in addition to entering and adhering to the above-described recesses. It was thought that the adhesive force increased through being held.
Further, the inventor directly adheres the iron powder having a particle diameter that does not enter the concave portion by sticking to the surface of the rice seed, in addition to the adhesion due to the holding power of the hair 5 of the rice seed. It was also found that it adheres.
Examining the state of the surface of the seed as described above, the particle size of the iron powder that is held by the hair 5 or the iron powder particle size that does not enter the recess through the hair 5 but adheres to the seed surface is 63 μm. The knowledge that it was preferable to contain the following iron powder in a predetermined amount was obtained.
And by containing the iron powder that enters the recesses on the surface of the rice seed, the iron powder that adheres to the surface of the rice seeds that does not enter the recesses, and the iron powder that is held by the hair 5, the finest iron is contained in the recesses of the rice seeds. The powder enters, the iron powder adheres to the seed surface above it, and further above it, the iron powder is held by the hair 5, and there is also a part where the iron powder is triple coated, the seed rolling It was found that the amount of peeling of the coating film caused by slipping can be reduced.

  Further, if the particle size of the iron powder is too large, not only is it difficult to enter the gaps between the hairs 5, but the gravity acting on the particles is large and the hairs 5 cannot hold the iron powder, so the adhesion effect is estimated to be small. . Accordingly, it was also found that the ratio of the iron powder having a particle size of 150 μm or more is preferably set to a predetermined amount or less.

  In addition, although the said examination was demonstrated taking the example of the rice seed, the same thing can be said if it is a seed which has an unevenness | corrugation and / or hair partially or entirely on the seed surface.

<Examination of binders>
Regarding the binder, the cause of the generation of aggregated particles was examined. As a result, it was found that the generation of aggregated particles is related to the particle size of the binder.

  In addition, although the said examination was demonstrated taking the rice seed as an example, the same thing can be said if it is a seed which has hair on the surface like a rice seed, for example, seeds, such as wheat, a carrot, a tomato.

  The present invention has been made on the basis of the above findings, and specifically comprises the following constitution.

(1) In the iron powder for seed coating according to the present invention, the mass ratio of iron powder having a particle diameter of 45 μm or less is more than 35%, less than 85%, and the mass ratio of iron powder having a particle diameter of 63 μm or less is more than 75%. It is characterized by being.

(2) Further, in the above (1), the mass ratio of the iron powder having a particle diameter of more than 150 μm is less than 10%.

(3) Further, in the above (1) or (2), the iron powder is produced by a reduction method or an atomization method.

(4) The iron powder-coated seed according to the present invention is characterized by being coated with the iron powder for seed coating described in any of (1) to (3) above.

(5) Further, in the above (4), the seed is a rice seed.

(6) The seed coating according to the present invention is a seed coating containing iron powder and a binder used to coat the seed surface, and the iron powder is a mass ratio of iron powder having a particle diameter of 45 μm or less. Is more than 35%, less than 85%, and the mass ratio of iron powder having a particle diameter of 63 μm or less is more than 75%, and the binder has an average particle diameter of 1 to 150 μm. is there.

(7) Further, in the above (6), the binding material contains a sulfate and / or a chloride.

(8) Further, in the above (6) or (7), the iron powder is characterized in that a mass ratio of iron powder having a particle diameter of more than 150 μm is less than 10%. .

(9) Further, in any of the above (6) to (8), the iron powder is manufactured by a reduction method or an atomization method.

(10) The seed according to the present invention is characterized in that the seed is coated with the seed coating agent according to any one of (6) to (9) above.

(11) Further, in the above (10), the seed is a rice seed.

In the iron powder for seed coating according to the present invention, the mass ratio of iron powder having a particle size of 45 μm or less is more than 35%, less than 85%, and the mass ratio of iron powder having a particle size of 63 μm or less is more than 75%, or Further, since the mass ratio of the iron powder having a particle diameter of more than 150 μm is less than 10%, seeds having irregularities and hairs on the seed surface, such as rice seeds, are retained by hair and passed through the hairs. It can be expected to adhere directly to the inside of the recess, and further to the inside of the concave portion of the fine irregularities, and a strong coating can be formed, and a coating with less iron powder falling off not only in the seeding process but also in the transportation process can be realized.
This makes it possible to save farm work and reduce production costs.

  Further, the seed coating agent according to the present invention is a seed coating agent containing iron powder and a binder used to coat the seed surface, and the iron powder has a mass ratio of iron powder having a particle diameter of 45 μm or less. Since the mass ratio of iron powder having a particle size of more than 35%, less than 85%, and a particle size of 63 μm or less is more than 75%, and the binder has an average particle size of 1 to 150 μm, For example, seeds such as rice seeds with hair on the surface can be expected to be retained by hair, and a coating with less iron powder falling off can be realized not only in the sowing process but also in the transport process, and the binder generates aggregated particles. Therefore, it is possible to improve the yield, make the coating components uniform, and improve the coating workability.

It is a secondary electron image of the surface of a rice seed. It is explanatory drawing explaining the state of the surface of a rice seed.

[Embodiment 1]
The iron powder for seed coating according to an embodiment of the present invention has a mass ratio of iron powder having a particle diameter of 45 μm or less, more than 35%, less than 85%, and an iron powder having a particle diameter of 63 μm or less. It is characterized by being over 75%. Moreover, in this Embodiment, the mass ratio of the iron powder whose particle diameter exceeds 150 micrometers is set to less than 10%.

The reason why the mass ratio of the iron powder having a particle diameter of 45 μm or less is more than 35% is that the iron powder enters and adheres to the concave portions of the fine irregularities on the seed surface to form a strong film.
In addition, the mass ratio of the iron powder having a particle size of 45 μm or less is less than 85% because the iron powder reacts rapidly with oxygen in the air as the content of the iron powder having a small particle size increases, and heat is generated. There is a possibility that the seed coated with iron powder may be damaged or cause a fire when handling a large quantity. Furthermore, if the content of fine iron powder is large, dust is easily generated and a clean working environment is maintained. It is difficult.

  The reason why the mass ratio of the iron powder having a particle diameter of 63 μm or less was set to more than 75% is that the iron powder having a particle diameter of 63 μm or less is held by the hair on the surface of the seed, or slipped between the hairs to the surface of the seed. Since it adheres by the adhesive force between particle | grains, it is the meaning which implement | achieves the triple coating mentioned above by containing the predetermined amount of iron powder of such a particle diameter.

  It is preferable that the mass ratio of the iron powder having a particle diameter exceeding 150 μm is less than 10%. This is because the iron powder having a particle diameter exceeding 150 μm cannot be expected to be held by hair and directly attached to the seed surface. The purpose is to reduce the particle size.

  In addition, the particle size distribution of iron powder can be evaluated by sieving using the method defined in JIS Z2510-2004.

  Examples of the method for producing iron powder in the present embodiment include a reduction method in which a mill scale is produced by reduction and an atomization method in which molten steel is produced by water atomization.

There is no limitation on the method of coating the seed with iron powder.
For example, as shown in the “Iron Coating Direct Seeding Manual 2010 (edited by the National Agricultural Research Center for Agricultural and Food Industry, Kinki Chugoku Shikoku Research Center)” Any method such as a method using a known mixer may be used.
As the mixer, for example, a stirring blade type mixer (for example, a Henschel mixer) or a container rotation type mixer (for example, a V type mixer, a double cone mixer, a tilt rotation type bread type mixer, a rotary mulberry type mixer, etc.) can be used. .
In addition, as shown in the iron coating submerged direct seeding manual 2010 described above, a coating reinforcing agent (binding material) such as calcined gypsum can be used for iron powder coating.

  The seeds coated with the iron powder for seed coating as described above are the iron powder-coated seeds of the present invention. Typical seeds to be coated are rice seeds. , Seeds such as carrots and tomatoes.

[Embodiment 2]
The second embodiment relates to a seed coating agent.
The seed coating agent according to Embodiment 2 is a seed coating agent containing iron powder used to coat the seed surface and sulfate and / or chloride as a binder, and the iron powder has a particle size of The mass ratio of iron powder of 45 μm or less is more than 35%, less than 85%, and the mass ratio of iron powder having a particle diameter of 63 μm or less is more than 75%, and the binder has an average particle diameter of 1 to 150 μm. It is characterized by being.
Hereinafter, the iron powder and the binder constituting the seed coating agent will be described in detail.

<Iron powder>
The iron powder of the present embodiment is the same as the iron powder of the first embodiment, and has the same effects as those described in the first embodiment.

<Binder>
The binder is composed of sulfate and / or chloride. Sulfates are calcium sulfate, potassium sulfate, magnesium sulfate and hydrates thereof. Moreover, a chloride is potassium chloride, calcium chloride, magnesium chloride, and these hydrates.
As for the mass ratio contained in the whole seed coating material of a binder, 0.1-80 mass% is preferable. This is because if the content ratio of the binder is 0.1% by mass or more, the strength of the coating film is not lowered and is suitable for practical use.
Moreover, if the content ratio of the binder is 80% by mass or less, not only the binder is not aggregated and the workability is not lowered, but also the effect of increasing the specific gravity of the coated seed which is the original purpose is obtained. is there.
In addition, as a more preferable range of the mass ratio contained in the whole seed coating material of a binder, it is 0.5-35 mass%. This is because it is more preferable to make this range to increase the strength of the coating and to prevent the aggregation of the binder.
The average particle size of the binder is 1 to 150 μm. This is because if the average particle size of the binder is less than 1 μm, the aggregated particles generated during the coating operation increase and the workability is remarkably reduced. On the other hand, when the average particle diameter of the binder exceeds 150 μm, the adhesion of the iron powder is reduced and the strength of the coating film is reduced.

There is no limitation on the method of coating the seed with the seed coating agent.
For example, as shown in the “Iron Coating Direct Seeding Manual 2010 (edited by the National Agricultural Research Center for Agricultural and Food Industry, Kinki Chugoku Shikoku Research Center)” Any method such as a method using a known mixer may be used.
As the mixer, for example, a stirring blade type mixer (for example, a Henschel mixer) or a container rotation type mixer (for example, a V type mixer, a double cone mixer, a tilt rotation type bread type mixer, a rotary mulberry type mixer, etc.) can be used. .
In addition, as shown in the iron coating submerged direct sowing manual 2010 described above, a seed coating agent containing iron powder and a binder is used for iron powder coating.
As a specific method for coating seeds with iron powder, iron powder, a binder, and seeds may be put into the above-mentioned mixer, and the mixer may be rotated while spraying water.

In order to confirm the effect of the iron powder for seed coating according to the present invention, rice seeds were coated using Invention Examples 1 to 6 which are iron powders having various particle size distributions as invention examples of the present invention. In addition, as a comparative example, rice seeds were coated using Comparative Examples 1 to 3, which are iron powders having a particle size distribution outside the range of the particle size distribution of the present invention.
Iron powder coating (coating) was performed according to the method described in the above-mentioned “Iron Coating Direct Sowing Manual 2010”. Specifically, it is as follows.

First, seed candy, calcined gypsum and several types of iron powder were prepared. Next, using an inclined rotary bread mixer, 20 kg of seeds (seeds) are coated with 10 kg of iron powder and 1 kg of calcined gypsum while spraying an appropriate amount of water, and 0.5 kg of calcined gypsum is finished. Coated.
A method for evaluating the strength of the coating film against rolling friction and sliding friction of seed coated with iron powder has not been established.
Therefore, the coating strength was investigated in accordance with the test method described in JPMA P 11-1192 “Method for measuring the Latra value of metal compact”. This test method will be referred to as a ratra test.

In the ratra test, 20 ± 0.05 g of seed coated with iron powder was enclosed in a rattle tester cage, and the cage was rotated at a rotational speed of 87 ± 10 rpm.
The number of revolutions was 1000 times according to the above test method, but the number of revolutions was set to 1200 times for the following reason.
In recent years, as the amount of coated seed produced, transported, and stored increases, the load on the seed tends to increase, and higher wear resistance has become necessary. Therefore, in the present invention, in order to reflect this situation and perform the test under more severe conditions, the number of rotations of the car in the ratra test is set to 1200 times. According to this method, rolling and sliding frictional forces are applied between the seeds and between the seeds and the inner surface of the basket container as the seeds flow while rolling in the basket.
Therefore, when this method is applied, the strength of the coating film when the rolling friction force and the sliding friction force are applied in combination can be evaluated.
Table 2 shows the particle size distribution of the iron powder and the weight reduction rate in the ratra test. The weight reduction rate was obtained from the following calculation formula.
Weight reduction rate = (mass of coating peeled off in ratra test) / (mass of seed before test) × 100 (%)
Therefore, it can be determined that the smaller the weight reduction rate, the higher the strength of the coating.

As shown in Table 2, all of the examples described in Invention Examples 1 to 6 are “iron having a mass ratio of iron powder having a particle size of 45 μm or less and more than 35%, less than 85%, and a particle size of 63 μm or less. The mass ratio of the powder is within the range of the particle size distribution of the present invention, which is “over 75%”, and the weight reduction rate in the Latra test is 3.5% or less.
On the other hand, in Comparative Examples 1 to 4 that deviate from the above particle size distribution, the weight reduction rate in the ratra test is 4% or more.
From this, it was demonstrated that the weight reduction rate can be significantly suppressed by making the particle size distribution of the iron powder within the range of the present invention.
In Table 2, the numbers whose particle size distributions in Comparative Examples 1 to 4 are outside the scope of the present invention are underlined.

  In Invention Examples 1, 2, 3, 4, and 6, the mass ratio of the iron powder having a particle diameter exceeding 150 μm is less than 10%, and the weight reduction rate in these ratra tests is 3.0% or less. It is low. On the other hand, in Invention Example 5, the mass ratio of the iron powder having a particle diameter exceeding 150 μm is 11.6% and more than 10%. From this, it can be seen that the adhesive force of the iron powder can be further increased by controlling the mass ratio of the iron powder having a particle diameter exceeding 150 μm to less than 10%.

  Experiments were conducted to confirm the effect of the seed coating agent according to the present invention. Since this experiment was performed for each of the iron powder and the binder constituting the seed coating agent, each experiment will be described below.

<Effect confirmation about iron powder particle size>
In order to confirm the effect of the iron powder constituting the seed coating agent according to the present invention, the iron powder (Invention Examples 1 to 6 in Table 2) used in Example 1 was used as an invention example of the present invention. Coating was performed. As a comparative example, rice seeds were coated using the iron powder (Comparative Examples 1 to 3) used in Example 1 as the iron powder having a particle size distribution outside the range of the particle size distribution of the present invention.
As the binder, calcined gypsum having an average particle size of 12 μm was used.
The coating (coating) of the seed coating agent was performed according to the method described in the above-mentioned “Iron coating direct sowing manual sowing manual 2010”. Specifically, it is as follows.

First, seed candy, calcined gypsum and several types of iron powder were prepared. Next, 5 kg of iron powder and 0.5 kg of calcined gypsum are coated on 10 kg of seed (seed seed) while spraying an appropriate amount of water using an inclined rotary type bread mixer, and further 0.25 kg of calcined gypsum Coated to finish.
A method for evaluating the strength of a coating film against rolling friction and sliding friction of seeds coated with a seed coating agent has not been established.
Therefore, the coating strength was investigated in accordance with the test method described in JPMA P 11-1992 “Method for measuring the Latra value of metal compact”. This test method will be referred to as a ratra test.

In the ratra test, 20 ± 0.05 g of seed coated with a seed coating agent was sealed in a rattle tester cage, and the cage was rotated 1200 at a rotational speed of 87 ± 10 rpm. According to this method, rolling and sliding frictional forces are applied between the seeds and between the seeds and the inner surface of the basket container as the seeds flow while rolling in the basket.
Therefore, when this method is applied, the strength of the coating film when the rolling friction force and the sliding friction force are applied in combination can be evaluated.
Table 3 shows the particle size distribution of the iron powder of the seed coating agent and the weight reduction rate in the ratra test. In Table 3, Invention Examples 7 to 12 are seed coatings comprising the iron powders of Invention Examples 1 to 6 in Table 2 and calcined gypsum having an average particle size of 12 μm, and Comparative Examples 4 to 6 are Comparative Examples 1 to 1 in Table 2. A seed coating comprising 3 iron powder and calcined gypsum having an average particle size of 12 μm.
The weight reduction rate was obtained from the following calculation formula.
Weight reduction rate = (mass of coating peeled off in ratra test) / (mass of seed before test) × 100 (%)
Therefore, it can be determined that the smaller the weight reduction rate, the higher the strength of the coating.

As shown in Table 3, all of the examples described in Invention Examples 7 to 12 are “iron powder with a particle size of more than 35%, less than 85%, and a particle size of 63 μm or less. Is within the range of the particle size distribution of the present invention, and the weight reduction rate in the ratra test is 3.6% or less.
On the other hand, in Comparative Examples 4 to 6 outside the range of the particle size distribution, the weight reduction rate in the ratra test is 4.6% or more.
From this, it was demonstrated that the weight reduction rate in the ratra test can be significantly suppressed by making the particle size distribution of the iron powder of the seed coating agent within the range of the present invention.
In Table 3, the numbers whose particle size distributions in Comparative Examples 4 to 6 are outside the scope of the present invention are underlined.

  In Invention Examples 7, 8, 9, 10, and 12, the mass ratio of the iron powder having a particle diameter of more than 150 μm is less than 10%, and the weight reduction rate in these ratra tests is 3.0% or less. Therefore, it can be seen that the adhesive force of the iron powder can be increased by making the mass ratio of the iron powder having a particle diameter of more than 150 μm less than 10%.

<Effect confirmation about binder average particle diameter 1>
Next, an experiment for confirming the effect of the average particle diameter of the binder was performed. As the binder, calcined gypsum was used, and a plurality of average particle diameters were prepared as shown in Table 4. The iron powder used in Example 7 used in the above experiment, ie, 45 μm or less, 44.3%, 63 μm or less, 76.0%, 63 μm or more, 150 μm or less, 23.3%, 150 μm or more. Used an iron powder having a particle size distribution of 0.7%.
The method of covering the rice seeds was the same as that performed in the above-mentioned “confirmation of effect on iron powder particle size”.
During the coating operation, that is, when iron powder, calcined gypsum, and rice seeds were put into an inclined rotary bread mixer and mixed, the state of occurrence of aggregated particles was visually confirmed and evaluated.
Moreover, the coating strength of the rice seeds coated with iron powder after the completion of the coating operation was examined by a ratra test.
The results are shown in Table 4.

From the results shown in Table 4, regarding the aggregated particles, when the average particle size of calcined gypsum is 0.6 μm, there are many aggregated particles generated during the coating operation, and when the average particle size of calcined gypsum is 1 μm or more, the aggregated particles generated during the coating operation. It was confirmed that there were few.
Regarding the coating strength, when the average particle size of the calcined gypsum is 0.6 μm, the weight reduction rate in the ratra test is as large as 5.9%, but the average particle size of the calcined gypsum is 1.2 to 145 μm. In the range, the weight reduction rate was less than 4.0%, which was within the allowable range, and when the average particle size of calcined gypsum was 203 μm, it was confirmed that the weight reduction rate was as extremely high as 15.5%.

<Effect confirmation about binder average particle diameter 2>
Next, using potassium chloride as a binder, an experiment was conducted to confirm the effect of the average particle size of the binder. As shown in Table 5, those having a plurality of average particle diameters were prepared. The iron powder used in Example 7 used in the above experiment, ie, 45 μm or less, 44.3%, 63 μm or less, 76.0%, 63 μm or more, 150 μm or less, 23.3%, 150 μm or more. Used an iron powder having a particle size distribution of 0.7%.
The method of covering the rice seeds was the same as that performed in the above-mentioned “confirmation of effect on iron powder particle size”.
During the coating operation, that is, when iron powder, potassium chloride, and rice seeds were put into an inclined rotary bread mixer and mixed, the state of occurrence of aggregated particles was visually confirmed and evaluated.
Moreover, the coating strength of the rice seeds coated with iron powder after the completion of the coating operation was examined by a ratra test.
The results are shown in Table 5.

From the results shown in Table 5, it is confirmed that when the average particle size of potassium chloride is 0.5 μm, there are many aggregated particles generated during the coating operation, and when the average particle size of potassium chloride is 1 μm or more, there are few aggregated particles generated during the coating operation. It was done.
Regarding the coating strength, when the average particle size of potassium chloride is 0.5 μm, the weight reduction rate in the ratra test is as large as 4.5%, but the average particle size of potassium chloride is 1.5 to 140 μm. In the range, the weight reduction rate was less than 4.0%, which was within the allowable range, and when the average particle size of potassium chloride was 250 μm, it was confirmed that the weight reduction rate was as extremely large as 13.6%.

From the above results, it was demonstrated that the average particle size of calcined gypsum and potassium chloride as a binder is related to the generation of aggregated particles and the coating strength.
And it was also confirmed that it is 1-150 micrometers as a preferable range of the average particle diameter of a binder.

In the above embodiment, calcined gypsum and potassium chloride have been described as examples of the binder, but the same applies to other sulfates, chlorides, or mixtures of sulfates and chlorides. In addition to sulfates and chlorides, substances that promote the oxidation reaction of iron powder such as sulfites, sulfides, nitrates, nitrites, hydrates of these salts, or mixtures of these salts It can be used as a binder.
Among the above binders, calcined gypsum is particularly suitable because it has a very small adverse effect on plants and human bodies, and is inexpensive and easily available.

1 seed rice 3 rice husk 5 hair

Claims (6)

A seed coating agent containing iron powder and a binder used to coat the seed surface,
The iron powder has a mass ratio of iron powder having a particle diameter of 45 μm or less, more than 35%, less than 85%, and a mass ratio of iron powder having a particle diameter of 63 μm or less is more than 75%,
The binder is a seed coating agent having an average particle diameter of 1 to 150 μm.   The seed coating agent according to claim 1, wherein the binder contains sulfate and / or chloride.   The seed coating agent according to claim 1 or 2, wherein the iron powder has a mass ratio of iron powder having a particle diameter of more than 150 µm of less than 10%.   The seed coating agent according to any one of claims 1 to 3, wherein the iron powder is produced by a reduction method or an atomization method.   A seed coating agent-coated seed obtained by coating a seed with the seed coating agent according to any one of claims 1 to 4. 6. The seed coating agent-coated seed according to claim 5, wherein the seed is a rice seed.