WO2013014812A1

WO2013014812A1 - Iron powder for coating seeds and iron-powder-coated seeds

Info

Publication number: WO2013014812A1
Application number: PCT/JP2011/073279
Authority: WO
Inventors: 河野　貴史; 政志藤長
Original assignee: Ｊｆｅスチール株式会社
Priority date: 2011-07-27
Filing date: 2011-10-04
Publication date: 2013-01-31
Also published as: KR20140034933A; JP2013046598A; CN103648263B; CN103648263A; JP2013212119A; JP5403030B2

Abstract

In this iron powder for coating seeds, by means of the mass fraction of iron powder having a particle size of no greater than 45 μm being 35-85% exclusive, and the mass fraction of iron powder having a particle size of no greater than 63 μm being at least 75%, it is possible to obtain an iron powder that is for coating seeds and that can achieve a coating having low shedding of iron powder not only in a sowing step but also in a transport step, and iron-powder-coated rice seeds coated by the iron powder for coating seeds, and it is possible to obtain an iron powder that is for coating rice seeds and that has a low likelihood of damaging rice seeds and is easily handled, and iron-powder-coated rice seeds coated with the iron powder for coating rice seeds.

Description

Iron powder for seed coating and seed coated with iron powder

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

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 transportation and sowing process is difficult to peel off. When the iron powder coating is peeled off, the specific gravity of the seeds is reduced and the above-mentioned merits are not obtained. 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 rice seeds, iron powder, and 0.5-2% by mass of sulfate (excluding calcium sulfate) and / or chloride are added, and water is added to granulate. 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

However, the present inventors have newly found the following problems in the prior art.
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 ratio 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, the iron powder reacts rapidly with oxygen in the air, and the seed coated with the iron powder may be damaged by heat generation. . Also, fire prevention measures are required 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.

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. .

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. It was thought that a stronger coating could be formed by iron powder entering and adhering to the recesses in the irregularities.
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)” (Non-Patent Document 1), the way the hair 5 grows is also dense. In particular, the distance between the hairs 5 in the region where the hairs 5 are dense is 50 to 150 μm.
When the inventor coats the iron powder on the seed pod 1, the iron powder disposed between the hairs 5 by the elastic action of the hairs 5 is added to the hairs 5 in addition to entering and attaching to the recesses described above. It was thought that the adhesive force was increased by being held in the water.
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.
The state of the seed surface as described above was examined, and the iron powder particle size that was held by the hair 5 or the iron powder particle size that did not pass through the hair 5 and did not enter the recess but adhered to the seed surface was determined to be 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.

In addition, 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 that the adhesion effect is estimated to be small. . Therefore, the knowledge that the ratio of the iron powder having a particle diameter of 150 μm or more is preferably set to a predetermined amount or less was also obtained.

In addition, although the above-described examination has been described by taking rice seeds as an example, similar to rice seeds, other seeds are seeds having irregularities and / or hairs on the whole or part of the seed surface, The effect of the present invention is expected when the shape of the unevenness and the way of hair growth (intervals, etc.) are similar to rice seeds. Examples of seeds having hair on the surface include seeds such as wheat, carrot and tomato.

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

(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 what is.

(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 obtained by coating the iron powder for seed coating described in any of (1) to (3) above.

(5) Moreover, in the thing as described in said (4), a seed is a rice seed.
The iron powder-coated seed according to the present invention is preferably made of very fine iron powder (preferably having a particle size of 45 μm or less, more preferably an average particle size of 1 to 40 μm) that enters the recesses on the seed surface. A layer (first iron powder layer);
A layer made of fine iron powder (preferably mainly composed of about 45 to 63 μm in diameter) that is located above the first iron powder layer and does not enter the recess and adheres to the seed surface (second iron powder) Layer), and
A layer of iron powder (preferably composed mainly of an average particle size of about 63 to 150 μm) of an iron powder (third iron powder layer which is located above the second iron powder layer and held by the hair of seeds )When,
It is what has. Such a three-layer structure does not need to be formed on the entire surface of the seed, but it is preferable that the three-layer structure is formed on 50% or more of the seed surface.

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

FIG. 1 is a secondary electron image of the surface of a rice seed, FIG. 1 (a) is an overall image, FIG. 1 (b) is a partially enlarged photograph, and FIG. 1 (c) is a further enlarged photograph. . FIG. 2 is an explanatory diagram for explaining the state of the surface of the rice seed.

The iron powder for seed coating according to one 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 a mass ratio of iron powder having a particle diameter of 63 μm or less. It is characterized by being over 75%. Moreover, in this Embodiment, Preferably the mass ratio of the iron powder whose particle diameter exceeds 150 micrometers is set to less than 10%. In addition, mass ratio is a ratio with respect to iron powder whole quantity.

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.
Moreover, the reason why the mass ratio of the iron powder having a particle diameter of 45 μm or less is set to less than 85% is as follows. When the content of iron powder with a fine particle size increases, the iron powder reacts rapidly with oxygen in the air, and the seed coated with the iron powder may be damaged by heat generation. Also, fire prevention measures are required when handling large quantities. Furthermore, if there is much content of fine iron powder, it will be easy to produce dust and it will be difficult to maintain a clean work environment. Preferably it is 80% or less, More preferably, it is 70% or less.
The average particle size of iron powder of 45 μm or less is preferably about 1 to 40 μm.

The reason why the mass ratio of the iron powder having a particle diameter of 63 μm or less exceeds 75% is as follows. The iron powder having a particle size of 63 μm or less is held by the hair on the surface of the seed, or passes through the hair and adheres to the surface of the seed by the adhesive force between the particles. For this reason, it is the meaning which implement | achieves the triple coating mentioned above by containing the predetermined quantity of iron powder of such a particle diameter.
In addition, since virtually the total amount of iron powder may be 63 μm or less (that is, 100%), no upper limit is defined.

It is preferable that the mass ratio of the iron powder having a particle diameter of more than 150 μm is less than 10% because the iron powder having a particle diameter of more than 150 μm cannot be expected to be held by hair or directly attached to the seed surface. The purpose is to reduce the particle size.
Iron powder having a particle diameter exceeding 150 μm may not be contained (that is, 0%).

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

Although any known method is suitable as a method for producing iron powder in the present embodiment, a reduction method in which the mill scale is reduced and produced (the obtained iron powder is called reduced iron powder) or molten steel with water or the like An atomizing method for producing by atomization (the obtained iron powder is referred to as atomized iron powder) is exemplified. The iron powder may contain alloy components and impurities in addition to iron, but is preferably about 10% by mass or less. In particular, so-called pure iron powder containing 90% by mass or more of Fe is preferable.

There is no limitation on the method of coating the seed with the seed coating iron powder.
For example, “Iron-coated coal water direct sowing manual 2010 (edited by National Agricultural Research Center for Agricultural and Food Industry, Kinki Chugoku Shikoku Agricultural Research Center)” (Non-Patent Document 2) As shown in 6 to 14, any method such as manual coating (coating) or a method using a conventionally 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 above-mentioned “Iron-Coated Carbonated Water Direct Sowing Manual 2010”, a coating reinforcing agent such as calcined gypsum can be used for iron powder coating.

In order to confirm the effect of the iron powder for seed coating according to the present invention, rice seed coating using Invention Examples 1 to 8 which are iron powders of various particle size distributions (so-called pure iron powder) as invention examples of the present invention. Went. As a comparative example, rice seeds were coated using Comparative Examples 1 to 4, which are iron powders having a particle size distribution outside the range of the particle size distribution of the present invention.
The coating (coating) of the iron powder was performed according to the method described in the above-mentioned “Iron-coated coal water 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 a green compact” (Non-patent Document 3). 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 is 1000 times according to the above test method, but the number of rotations 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 8 are “iron mass ratio of iron powder having a particle diameter of 45 μm or less is more than 35%, less than 85% and particle diameter is 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, 6, 7, and 8, the mass ratio of the iron powder having a particle diameter exceeding 150 μm is less than 10%, and the weight loss rate in these ratra tests is 3%. It is lower as below. 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 adhesion of the iron powder can be further increased by controlling the mass ratio of the iron powder having a particle diameter of more than 150 μm to less than 10%.

Since the iron powder for seed coating according to the present invention can realize a coating with less iron powder dropping not only in the sowing process but also in the transportation process, it is possible to save labor in farm work and reduce the production cost of agricultural products.

1 seed rice 3 rice husk 5 hair

Claims

A seed coating iron powder in which the mass ratio of iron powder having a particle diameter of 45 μm or less is more than 35% and less than 85%, and the mass ratio of iron powder having a particle diameter of 63 μm or less is more than 75%.
The iron powder for seed coating according to claim 1, wherein the mass ratio of the iron powder having a particle diameter of more than 150 µm is less than 10%.
The iron powder for seed coating according to claim 1 or 2, wherein the iron powder is an iron powder produced by a reduction method or an atomization method.
An iron powder-coated seed obtained by coating a seed with the iron powder for seed coating according to any one of claims 1 to 3.
The iron powder-coated seed according to claim 4, wherein the seed is a rice seed.