JP5994283B2 - Iron powder for rice seed coating and rice seed - Google Patents

Description

  The present invention relates to an iron powder suitable for rice seed coating and a seed coated with iron powder.

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 such that the ratio of the particle diameter of 45 μm or less is 85% or less, and the ratio of the fine iron powder is too small. In this way, when the proportion of fine iron powder is too small and the amount of coarse iron powder is excessive, the number of particles for coating the iron powder surface is insufficient, and it is difficult to form a uniform film, resulting in a film. Strength may be reduced.

Moreover, in patent document 1, as a method of coat | covering a rice seed with iron powder, it is "Sulfate (except calcium sulfate except 0.5-2% by mass ratio with respect to a rice seed, iron powder, and iron powder). ) And / or chloride, and then add water and granulate.
An important factor in coating the surface of rice seeds with iron powder is to eliminate variation between rice seeds, but Patent Document 1 does not disclose anything about this.

  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.

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.
The surface structure of the seed rice is detailed in page 21 of “Seeing the Microscopic Structure of Rice (by Takamasa Mezaki)”. The interval between the irregularities is about 50 μm. Therefore, fine iron powder having a particle size of less than about 50 μm adheres to the recesses, thereby eliminating the gap between the seed surface and the coating and forming a strong coating.

  Furthermore, microscopically, as shown in FIG. 1 (c), there are many fine vertical grooves having a width of about 10 μm or less that divide the uneven structure on the seed vat surface. By filling these fine vertical grooves with iron powder, the iron powder coating formed into a film by the corrosion of iron powder exhibits the "wedge effect" due to the iron powder filled in the fine vertical grooves. It is considered that it is firmly bonded to the seed soot, and thus the coating strength can be further increased.

From the above studies, the inventor considers that there is an appropriate range for the particle size of the iron powder that can be firmly attached to seeds having such irregularities and grooves, and effectively exhibits the above-mentioned attachment form. The iron powder particle diameter for making it investigate was examined. As a result, by including a certain amount of iron powder having a particle size of 45 μm or less, adhesion to the recesses and filling into the fine grooves are promoted, and the coating strength is increased, and the coating film is accompanied by rolling and sliding of the seeds. The knowledge that the amount of peeling can be reduced was obtained.
On the other hand, since iron powder having a particle diameter exceeding 45 μm cannot enter the inside of the recess or groove, voids remain between the seed surface and the iron powder coating, resulting in a decrease in the adhesion of the coating. It is estimated that the strength decreases.

The inventor also examined the particle size of the iron powder retained by the holding power of the hair 5 in rice seeds in addition to the seed adhesion behavior in the recesses on the seed surface and the filling behavior in the grooves.
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, and when the seed pod 1 is coated with iron powder, the elastic action of the hair 5 It is presumed that the adhesion force is increased by holding the iron powder arranged between the bristles 5 to the bristles 5.
As shown on page 21 of “Seeing the Microscopic Structure of Rice (by Takamasa Mezaki)”, the way the hairs 5 grow is also dense. In particular, it is considered that the adhesion is enhanced by the iron powder being held by the hairs 5 at the site where the hairs 5 are dense, and the spacing of the hairs 5 at this site is 50 to 150 μm.
Therefore, if the particle size of the iron powder is too large, not only does it not easily enter the gap between the hairs 5, but also the gravity acting on the particles is large and the hairs 5 cannot hold the particles, so the adhesion effect is estimated to be small. Therefore, it was also found that the ratio of the iron powder having a particle diameter of 150 μm or more that cannot be expected to be retained by the bristles 5 is preferably set to a predetermined amount or less.

  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 a groove | channel and / or an unevenness | corrugation and / or hair in the whole seed surface or a part.

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

(1) The iron powder for seed coating according to the present invention is an iron powder used for coating seeds, the mass ratio of iron powder having a particle diameter of 45 μm or less is more than 85%, and contains metallic iron The ratio is 30.0% by mass or more and 99.0% by mass or less.

(2) Moreover, the iron powder used to coat the seeds, the mass ratio of the iron powder having a particle diameter of 45 μm or less is more than 85%, and the fluidity is 40 (sec / 50 g) or less. It is characterized by.

(3) Moreover, the iron powder used to coat the seeds is characterized in that the mass ratio of the iron powder having a particle size of 45 μm or less is more than 85% and the angle of repose is 45 degrees or less. It is.

(4) Further, in any of the above (1) to (3), the mass ratio of the iron powder having a particle diameter of more than 150 μm is less than 10%.

(5) Moreover, in the thing in any one of said (1) thru | or (4), iron powder was manufactured by the reduction method or the atomizing method, It is characterized by the above-mentioned.

(6) Moreover, the seed which concerns on this invention coat | covers the iron powder for seed coating | coated in any one of said (1) thru | or (5), It is characterized by the above-mentioned.

(7) Further, in the above (6), 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 diameter of 45 μm or less is more than 85%, and the content ratio of metallic iron is 30.0 mass% or more and 99.0 mass% or less. Therefore, seeds such as rice seeds with irregularities, grooves and hairs on the seed surface can be expected to adhere to the inside of the grooves and to the recesses and be retained by the hairs, and also ensure stable rust formation. In addition to the sowing process, a coating with less iron powder falling off can be realized in the transport process.
This makes it possible to save farm work and reduce production costs.

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.

In the iron powder for seed coating according to an embodiment of the present invention, the mass ratio of iron powder having a particle diameter of 45 μm or less is more than 85%, and the content ratio of metallic iron is 30.0 mass% or more and 99.0. It is characterized by being not more than mass%.
Moreover, in this Embodiment, the mass ratio of the iron powder whose particle diameter exceeds 150 micrometers is set to less than 10%.
Hereinafter, the reason why the particle size distribution and the content ratio of metallic iron are defined as described above will be described.

<Particle size distribution>
The reason why the mass ratio of the iron powder having a particle diameter of 45 μm or less is more than 85% is that the iron powder penetrates and adheres to the inside of the fine groove part or the concave part on the seed surface, and particularly the fine groove is filled with the iron powder. This is because the film formed by the corrosion of the iron powder is firmly joined to the seed pods by the wedge effect of the iron powder filled in the groove, and as a result, the iron powder forms a strong film.
The mass ratio of iron powder having a particle size of 45 μm or less is preferably 90% or more. More preferably, it is 95% or more.

  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.

<Content ratio of metallic iron>
The content ratio of metallic iron in the iron powder for seed coating according to the present embodiment is 30.0 mass% or more and 99.0 mass% or less.
The reason why the content ratio of metallic iron is 31.3 mass% or more is that when the content ratio of metallic iron is less than 30.0 mass%, the amount of generated rust is small and the coating strength with iron powder becomes weak. It is preferable that it is 31.3 mass% or more.
Moreover, the content ratio of metallic iron was made 99.0% by mass or less because if the content ratio of metallic iron exceeds 99.0% by mass, the oxidation reaction at the time of rusting proceeds rapidly, and the calorific value at that time This greatly damages the seed and reduces the germination rate. It is preferable that it is 98.9 mass% or less.

Control of the content ratio of metallic iron in the iron powder for seed coating is performed as follows.
By controlling the oxygen concentration in the atmosphere in the atomizing process of iron powder, the atmospheric oxygen concentration in the reduced iron powder manufacturing process, and further the oxygen concentration and hydrogen concentration when finishing heat treatment of atomized iron powder and reduced iron powder, The degree of oxidation of the iron powder can be controlled, and consequently the content ratio of metallic iron in the iron powder can be controlled.

The method for seed coating with the iron powder for seed coating is not particularly limited.
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 mixer (for example, a Henschel mixer) or a container rotation type mixer (for example, a V-type mixer, a double cone mixer, an inclined rotation type bread type mixer, a rotary mulberry type mixer, etc.) can be used. .
Further, as shown in the iron coating soaking direct sowing manual 2010 described above, a coating reinforcing agent such as calcined gypsum can be used for iron powder coating.

According to the seed coating iron powder of the present embodiment, for seeds such as rice seeds having irregularities, grooves and hairs on the seed surface, it can be expected to adhere to the inside of the grooves and recesses and be retained by the hairs, Moreover, the formation of rust can be ensured and a stable coating can be realized, and a coating with less iron powder dropping can be realized not only in the sowing process but also in the transportation process.
In addition, the said effect of the iron powder for seed coating | coated which concerns on this Embodiment has been confirmed in Example 1 mentioned later.

[Embodiment 2]
The iron powder for seed coating according to the present embodiment is characterized in that the mass ratio of the iron powder having a particle diameter of 45 μm or less is more than 85% and the fluidity is 40 (sec / 50 g) or less. It is.
The particle size distribution is the same as in the first embodiment, and the reason for defining the particle size distribution is the same as in the first embodiment. In the following, the reason for defining the fluidity will be described.

<Fluidity>
The fluidity of the seed coating iron powder according to the present embodiment is set to 40 (sec / 50 g) or less.
The fluidity is defined in JIS Z2502: 2000 as a method for evaluating the fluidity of metals.
According to JIS Z2502: 2000, the rheometer is composed of a funnel, a funnel support, a support bar, and a support base, and the shape and dimensions of each dimension funnel are defined. Transfer 50 g of metal powder dried at 105 ± 5 ° C. to the funnel, open the orifice at the bottom of the funnel, and measure the time from the moment the orifice is opened until the last powder leaves the orifice. It evaluates that fluidity | liquidity is so favorable that said time is short.
The definition of fluidity is the time (sec) required for 50 g of powder to pass through the orifice, and the unit is (sec / 50 g).

The reason why the fluidity of the seed coating iron powder is set to 40 (sec / 50 g) or less is to reduce variation in the coating of the seed coating iron powder among the seeds.
The relationship between coating variation and fluidity will be described below.
As a method of coating seeds with iron powder for seed coating, iron powder for seed coating, calcined gypsum (calcium sulfate hydrate) and seeds are put into a rotating container, and iron powder and gypsum are sprayed on the seed surface while spraying water. Coating. In such a process, when the fluidity of the seed coating iron powder is large, adhesion unevenness occurs, and the variation in the coating of the seed coating iron powder among the seeds increases. Conversely, if the fluidity of the seed coating iron powder is small, adhesion unevenness does not occur, and the variation in coating between seeds is reduced.

The method for controlling the fluidity of the seed-coated iron powder is performed as follows.
The particle size distribution and shape of the iron powder have a great influence on the fluidity. Therefore, for example, to control the fluidity of water atomized iron powder, the particle size distribution and particle shape of the iron powder are controlled by the flow rate and diameter of the molten steel flow dropped from the nozzle, the flow rate of spray water, the flow rate and the spray angle, As a result, the fluidity can be controlled.
For reduced iron powder, the particle size distribution and particle shape of the iron powder can be controlled by selecting the raw iron oxide before reduction and the grinding method of the product after reduction. Can be controlled.

According to the seed coating iron powder of the present embodiment, for seeds such as rice seeds having irregularities, grooves and hairs on the seed surface, it can be expected to adhere to the inside of the grooves and recesses and be retained by the hairs, Also, stable coating can be realized by preventing variation in coating between seeds.
In addition, the said effect of the iron powder for seed coating | coated which concerns on this Embodiment has been confirmed in Example 2 mentioned later.

[Embodiment 3]
The iron powder for seed coating according to the present embodiment is characterized in that the mass ratio of iron powder having a particle diameter of 45 μm or less is more than 85% and the angle of repose is 45 degrees or less.
The particle size distribution is the same as in the first embodiment, and the reason for defining the particle size distribution is the same as in the first embodiment. In the following, the reason for defining the angle of repose will be described.

<Repose angle>
The angle of repose of the iron powder for seed coating according to the present embodiment is set to 45 degrees or less.
The angle of repose is the angle of the slope that maintains stability without spontaneous collapse when the seed coating iron powder is stacked, and the higher the fluidity, the smaller the angle of repose.
The reason why the angle of repose of the iron powder for seed coating is set to 45 degrees or less is to reduce the variation in the coating of the iron powder for seed coating between the seeds.

The relationship between the coating variation and the angle of repose will be described below.
As a method of coating seeds with iron powder for seed coating, iron powder for seed coating, calcined gypsum (calcium sulfate hydrate) and seeds are put into a rotating container, and iron powder and gypsum are sprayed on the seed surface while spraying water. Coating. In such a process, if the angle of repose of the iron powder for seed coating is large and the fluidity is low, uneven adhesion occurs, and the dispersion of the coating of the iron powder for seed coating between the seeds increases. Conversely, if the angle of repose of the iron powder for seed coating is small and the fluidity is high, uneven adhesion does not occur and the variation in coating between seeds is reduced.

The method for controlling the angle of repose of the iron powder for seed coating is as follows.
The particle size distribution and shape of the iron powder have a great influence on the angle of repose. Therefore, for example, in order to control the angle of repose for water atomized iron powder, the particle size distribution and particle shape of iron powder are controlled by the flow velocity and diameter of the molten steel flow dropped from the nozzle, the flow rate of spray water, the flow velocity and the spray angle, As a result, the angle of repose of the iron powder can be controlled.
For reduced iron powder, the particle size distribution and particle shape of the iron powder can be controlled by selecting the raw iron oxide before reduction and the grinding method of the product after reduction. As a result, the angle of repose of the iron powder is controlled. Can be controlled.

According to the iron powder for seed coating of the present embodiment, for seeds such as rice seeds having irregularities and hairs on the seed surface, holding by hair and direct attachment to the seeds through the hairs, A fine uneven portion can be expected to adhere to the inside of the recess, and a strong coating can be formed. Further, variation in coating between seeds can be prevented and stable coating can be realized.
In addition, the said effect of the iron powder for seed coating | coated which concerns on this Embodiment has been confirmed in Example 3 mentioned later.

  Since the experiment which confirms the effect of the iron powder for seed coating | coated shown to this Embodiment 1-3 was demonstrated in the following Examples 1-3.

Regarding the iron powder for seed coating according to the first embodiment, an experiment for confirming the effect of the particle size distribution was conducted.
Rice seeds were coated using Invention Examples 1 to 5 which are iron powders having various particle size distributions as Invention Examples. 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.
In addition, the metal iron content ratios of Invention Examples 1 to 5 and Comparative Examples 1 to 3 were controlled to be substantially constant 86% by mass.
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 a concrete mixer-type mixer, 60 kg of seeds (seed seeds) are coated with 30 kg of iron powder and 3 kg of calcined gypsum, and 1.5 kg of calcined gypsum is finished. did.
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 rotations was 1000 times according to the above test method, but the number of rotations was set to 1500 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 to carry out the test under more severe conditions, the number of rotations of the car in the ratra test is set to 1500 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 the examples described in Invention Examples 1 to 5 are “the iron powder for seed coating according to the present invention has a mass ratio of iron powder having a particle diameter of 45 μm or less of more than 85%”. It is within the range of the particle size distribution of the invention, and the weight reduction rate in the ratra test is less than 4%.
On the other hand, in Comparative Examples 1 to 3 deviating 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 3 are outside the scope of the present invention are underlined.

  Further, in Invention Example 5, the mass ratio of the iron powder having a particle diameter exceeding 150 μm is 12.2%, which exceeds 10%, and the weight reduction rate in the ratra test in this case is 3.8%. On the other hand, in the inventive examples 1 to 4 in which the mass ratio of the iron powder exceeding 150 μm is less than 10%, the weight loss rate in the Latra test is as low as less than 3.5%. It can be seen that the adhesiveness of the iron powder can be further increased by setting the mass ratio of the iron powder having a particle diameter of 45 μm or less to more than 85% and exceeding 150 μm to be less than 10%.

  When Invention Example 1 and Invention Example 2 are compared, the mass ratio of iron powder having a particle diameter of 45 μm or less in Invention Example 1 is 98.7%, and the mass ratio of iron powder having a particle diameter of 45 μm or less in Invention Example 2 is Although it is higher than 90.5%, the weight reduction rate is higher in Invention Example 1. This point is presumed that, in Invention Example 2, since the mass ratio of the particle diameter of more than 45 μm and 150 μm or less was large, there was an effect of retaining the seed surface hairs growing at intervals of 50 to 150 μm. Is done. In this sense, on the condition that iron powder having a particle diameter of 45 μm or less is contained at a mass ratio of more than 85%, iron powder having a particle diameter of more than 45 μm and 150 μm or less should be contained at a mass ratio of about 9.5%. Is particularly preferred.

Next, in order to confirm the effect of defining the metal iron content ratio of the seed coating iron powder according to Embodiment 1 to a predetermined value, as an example of the invention, the particle size distribution is within the scope of the present invention, and the metal iron content ratio The rice seeds were coated using Invention Examples 6 to 10 having a mass ratio of 30.0 to 99.0% by mass.
In addition, as comparative examples, the particle size distribution is within the scope of the present invention, but the ratio of metallic iron is 21.8 mass% outside the scope of the invention and Comparative Example 5 is 99.5 mass%. Rice seeds were coated.
In this experiment, since the main purpose was to confirm the effect on the content ratio of metallic iron, the particle size distribution was controlled to be almost the same.
Table 3 shows the particle size distribution of the iron powder for seed coating, the metal iron content ratio, the weight reduction rate in the ratra test, and the germination rate.
In addition, the germination rate was evaluated according to the “germination test” described in the iron-coated flooded direct seeding manual 2010 described above. Specifically, about 100 seeds and 20 mL of water were placed in a 9 cm diameter petri dish, and the seeds that were not germinated seeds were counted after standing at 25 ° C. for 1 week, and the germination rate was calculated.

  In Invention Examples 6 and 7 and Comparative Example 5 having a high metal iron ratio, the weight reduction rate in the ratra test is 2.6% or less. Therefore, by increasing the metal iron content ratio, the occurrence of rust is ensured. It is presumed that the strength of the coating could be increased.

On the other hand, in Comparative Example 4, the content ratio of metallic iron is as small as 21.8% by mass, and as a result, the weight reduction rate in the Latra test is as high as 16.5%. From this, it is surmised that since the metal iron content ratio is low outside the scope of the invention, the occurrence of rust is insufficient and the coating strength is lowered.
Moreover, in the comparative example 5 whose metal iron content ratio is 99.5 mass%, the weight reduction rate in the ratra test is not as high as 2.6%, but the germination rate is as low as 43%. This is presumed that the oxidation reaction at the time of the occurrence of rust progresses rapidly, and the amount of heat generated at that time is large, causing damage to the seeds.

  As described above, it is confirmed that the coating with high coating strength can be realized without damaging the seeds by setting the metal iron content ratio of the iron powder for seed coating to 30.0 mass% or more and 99.0 mass% or less. It was done.

Experiments were conducted for the case where the fluidity of the iron powder for seed coating according to Embodiment 2 was within the scope of the invention and the particle size distribution was changed in the same manner as in Example 1.
Table 4 shows the particle size distribution of the iron powder and the weight reduction rate in the ratra test.

The particle size distribution in Invention Examples 11 to 15 is the same as that of Invention Examples 1 to 5 of Example 1, and the particle size distribution in Comparative Examples 6 to 8 is the same as that of Comparative Examples 1 to 3 of Example 1.
Regarding the fluidity, both the invention example and the comparative example are controlled to 40 (sec / 50 g) or less, which is the scope of the invention, specifically 33.0 (sec / 50 g) to 38.0 (sec / 50 g). did.
The rice seed coating method with iron powder, the ratra test method and the like are the same as those shown in Example 1.

  As shown in Table 4, the weight reduction rate was the same as the result shown in Table 2 of Example 1, and it was confirmed that the influence of the particle size distribution was large on the weight reduction rate. That is, when the particle size distribution is within the scope of the invention, the adhesion of iron powder to rice seeds can be increased.

Next, in order to confirm the effect of the fluidity of the iron powder for seed coating according to the present invention, as an example of the present invention, the particle size distribution is within the scope of the present invention and the fluidity is 32.5 (sec / 50 g). ) Rice seeds were coated using Invention Examples 16 to 18 of 35.0 (sec / 50 g) and 40.0 (sec / 50 g).
Further, as comparative examples, the particle size distribution is within the scope of the present invention, but the comparative example 9 has a very high fluidity, and the comparative example 10 has no iron powder coating.
Table 5 shows the average mass (mg) and standard deviation (mg) of the iron powder-coated seed mass (100 grains) and the germination rate (%) corresponding to the particle size distribution and fluidity of the seed-coated iron powder. The method for evaluating the germination rate is the same as that shown in Example 1.

As shown in Table 5, those described in Invention Examples 16 to 18 have a standard deviation (mg) of iron powder-coated seed mass (100 grains) smaller than 12 (mg). It can also be seen that the smaller the fluidity, the smaller the standard deviation. And the thing of invention examples 16-18 has a germination rate of 94% or more, and is quite high.
In contrast, in Comparative Example 9, the standard deviation exceeds 15.3 (mg), and the germination rate is as low as 80%.
From the above, it can be seen that by reducing the fluidity of the seed coating iron powder, the variation in coating of the seed coating iron powder on the seed is reduced, and the germination rate is increased.
Further, if the fluidity is 40 (sec / 50g) or less, the germination rate is 94% or more, and if the fluidity is 35 (sec / 50g) or less, the germination rate is 98% or more. It turns out that it is more preferable.

Experiments were conducted for the case where the repose angle of the iron powder for seed coating according to Embodiment 3 was within the invention range and the particle size distribution was changed in the same manner as in Example 1.
Table 6 shows the particle size distribution of the iron powder and the weight reduction rate in the ratra test.

The particle size distribution in Invention Examples 19 to 23 is the same as that of Invention Examples 1 to 5 of Example 1, and the particle size distribution in Comparative Examples 11 to 13 is the same as that of Comparative Examples 1 to 3 of Example 1.
In addition, the angle of repose was controlled to 45 degrees or less, which is the scope of the invention in both the inventive example and the comparative example, specifically, 34 to 37 degrees.
The rice seed coating method with iron powder, the ratra test method and the like are the same as those shown in Example 1.

  As shown in Table 6, the weight reduction rate was the same as the result shown in Table 2 of Example 1, and it was confirmed that the influence of the particle size distribution was large regarding the weight reduction rate. That is, when the particle size distribution is within the scope of the invention, the adhesion of iron powder to rice seeds can be increased.

Next, in order to confirm the effect of defining the angle of repose of the iron powder for seed coating according to the present invention, as an example of the present invention, the particle size distribution is within the range of the present invention, and the angle of repose is 35 degrees and 40 degrees. Rice seeds were coated using Invention Examples 24-26 at 45 degrees.
Further, as comparative examples, the particle size distribution is within the scope of the present invention, but the comparative example 14 with an angle of repose of 48 degrees and the comparative example 15 without iron powder coating were used.
Table 7 shows the average particle size (mg) and standard deviation (mg) of the iron powder-coated seed mass (100 grains) and the germination rate (%) corresponding to the particle size distribution and angle of repose of the seed-coated iron powder. The method for evaluating the germination rate is the same as that shown in Example 1.

As shown in Table 7, the standard deviation (mg) of the iron powder-coated seed mass (100 grains) is smaller than 12 (mg) in the invention examples 24-26. It can also be seen that the smaller the angle of repose, the smaller the standard deviation. And the thing of invention examples 24-26 has a germination rate of 94% or more, and is quite high. In particular, if the angle of repose is 35 degrees or less, the standard deviation is 5.6 (mg) or less and the germination rate is 99% or more.
In contrast, in Comparative Example 14, the standard deviation exceeds 15.3 (mg) and the germination rate is as low as 80%.
From the above, it can be seen that by reducing the angle of repose of the iron powder for seed coating, the variation of the coating of the iron powder for seed coating on the seed is reduced and the germination rate is increased.
In addition, it can be seen that if the angle of repose is 45 degrees or less, the germination rate is 94% or more, and if the angle of repose is 35 degrees or less, the germination rate is 99% or more, which is more preferable.

1 seed rice 3 rice husk 5 hair

Claims (4)

Iron powder used to coat rice seeds,
An iron powder for covering rice seeds, wherein the mass ratio of iron powder having a particle diameter of 45 μm or less is more than 85% and the fluidity is 40 (sec / 50 g) or less. Iron powder used to coat rice seeds,
An iron powder for covering rice seeds, wherein the mass ratio of iron powder having a particle diameter of 45 μm or less is more than 85% and the angle of repose is 45 degrees or less. The iron powder for rice seed coating according to claim 1 or 2 , wherein the mass ratio of iron powder having a particle diameter of more than 150 µm is less than 10%. Rice seeds obtained by coating the seed coating iron powder according to any one of claims 1 to 3 .