JP2015166337A - Granular herbicide and method of producing granular herbicide - Google Patents

Abstract

Disclosed is a granular herbicide having excellent stability and capable of maintaining herbicidal performance for a long period of time. The granular herbicide of the present invention contains sodium chlorate, sodium hydrogen carbonate, and a binder, and the shape of 80% by mass or more thereof has a longest diameter / shortest diameter = 1.0 to 1. And a herbicide having a particle size of 2 mm or more. [Selection figure] None

Description

  The present invention relates to a granular herbicide and a method for producing the granular herbicide.

Herbicides containing either sodium chlorate or sodium bicarbonate have been used as herbicides for weeding paddy fields, field weeds, etc. (for example, Patent Document 1). These herbicides are mainly liquid in terms of ease of adjustment and handling. However, in order to obtain long-lasting durability, a granular herbicide is preferable (for example, Patent Document 2).
Further, in order to disperse granular herbicides uniformly in paddy fields and fields, studies are being conducted to reduce the granule size.

JP 2010-047489 A JP-A-5-186308

  However, when the granular material is less than a specific size, there is a problem that the combustibility is high and the risk of explosion due to impact is likely to occur, and handling is necessary. In addition, if it is determined as a dangerous article under the Fire Service Law, installation and handling of special equipment is obligated in every process such as transportation, storage, and manufacturing, resulting in an increase in production cost.

Moreover, since the shape of a granule is formed in a bowl shape in a normal production method, it is vulnerable to impact. For this reason, cracks occur in every process such as transportation, storage and production, and the size of the granular herbicide frequently occurs to a size equal to or smaller than a predetermined shape. That is, the sustainability of the planned herbicidal effect could not be maintained. Moreover, there is a problem that the risk under the Fire Service Law increases as the size decreases.
Therefore, there has been a demand for the development of a granular herbicide that has high stability and can maintain herbicidal performance for a long period of time.

  This invention is made | formed in view of the said problem, and it aims at providing the granular herbicide which is excellent in stability and can maintain herbicidal performance for a long period of time.

As a result of intensive studies, the present inventors have focused on making the shape and size of the granular herbicide a predetermined shape. Increasing the size of the granular herbicide raises the problem that the drying process is prolonged and the number of treatment steps is added, and the conventional flow of refining the granular substance to improve dispersibility is also considered. Contrary to this, it was hardly studied.
On the other hand, the present inventors set the shape and size of the granular herbicide to a predetermined size and form a granular herbicide having a specific component, so that the stability is high and the herbicidal performance can be maintained for a long time. The present invention was completed.
That is, this invention provides the following means in order to solve the said subject.

  (1) The granular herbicide of the present invention contains sodium chlorate, sodium hydrogen carbonate, and a binder, and the shape of 80% by mass or more has the longest diameter / shortest diameter = 1.0 to 1. 5 and the particle size is 2 mm or more.

  (2) The granular herbicide described in (1) above may be a compound in which the binding material as a constituent element thereof has thixotropic properties.

  (3) A method for producing a granular herbicide according to the present invention comprises a kneading step of adding water to a mixture containing sodium chlorate, sodium hydrogencarbonate and a binder, and extruding the mixed mixture. , An extruding step for forming pellets, a granulating step for granulating the pellets so as to satisfy the longest diameter / shortest diameter = 1.0 to 1.5, and the granulated granules are divided into sizes of 2 mm or more A classification step and a drying step of drying the classified granules;

  (4) In the method for producing a granular herbicide described in (3) above, in the kneading step, water having a weight of 7/100 to 20/100 may be added to the total weight of the mixture.

  (5) In the manufacturing method of the granular herbicide in any one of said (3) or (4), 300 cm / sec-450 cm / sec may be sufficient as the extrusion rate in the said extrusion process.

  The granular herbicide of the present invention contains sodium chlorate, sodium bicarbonate, and a binder, and the shape of 80% by mass or more satisfies the longest diameter / shortest diameter = 1.0 to 1.5. The particle size is 2 mm or more. Since the granular herbicide contains sodium chlorate and sodium bicarbonate at the same time, it is possible to achieve an effect of simultaneously realizing high combustion resistance and high herbicidal properties. Moreover, since the shape is close to a sphere and the size is 2 mm or more, the mechanical stability is high, and it is difficult to break even under impact. Therefore, there is no restriction under the Fire Service Law. At the same time, the sustained stability of the herbicidal effect can be increased.

  The method for producing a granular herbicide according to the present invention includes a kneading step of adding water to a mixture containing sodium chlorate, sodium bicarbonate, and a binder, kneading the mixture, extruding the mixed mixture, An extruding step to form, a granulating step for granulating the shape of the pellet so as to satisfy the longest diameter / shortest diameter = 1.0 to 1.5, and a classification step for dividing the granulated granule into sizes of 2 mm or more And a drying step of drying the classified granules. Therefore, the granular herbicide which is excellent in the above-mentioned stability and can maintain the herbicidal performance for a long time can be efficiently formed.

It is the schematic diagram which showed typically about the manufacturing method of the granular herbicide concerning 1 aspect of this invention. It is a flowchart of a dangerous goods 1st class confirmation test.

Hereinafter, a granular herbicide to which the present invention is applied and a method for producing the granular herbicide will be described in detail with reference to the drawings as appropriate.
In the drawings used in the following description, in order to make the characteristics of the present invention easier to understand, the characteristic parts may be shown in an enlarged manner for the sake of convenience, and the dimensional ratios of the respective components are different from actual ones. Sometimes. In addition, the materials, dimensions, and the like exemplified in the following description are examples, and the present invention is not limited to them, and can be appropriately changed and implemented without changing the gist thereof.

(About components)
The granular herbicide of the present invention contains sodium chlorate, sodium bicarbonate and a binder. Sodium chlorate is represented by the chemical formula NaClO ₃ and is the hydrochloride salt of sodium. Sodium bicarbonate is represented by the chemical formula NaHCO ₃ , is a sodium bicarbonate salt, and is also called sodium bicarbonate. All are compounds having a herbicidal effect.
Sodium chlorate has a high herbicidal effect. On the other hand, sodium hydrogen carbonate has high combustion resistance. Therefore, by simultaneously containing sodium chlorate and sodium hydrogen carbonate, high combustion resistance and high herbicidal properties can be realized at the same time.

  A binder shows the role for joining the compounds which have a herbicidal effect, and shape | molding it in a granular form. The binder is not particularly limited as long as the compounds can be connected to each other. , Soy flour, cereal flour, wood flour, bark flour, saw flour, Davaco stem flour, walnut shell flour, bran, fiber powder, organic solid carrier such as residue after extraction of plant extract, synthetic polymer such as ground synthetic resin , Viscosity (for example, kaolin, bentonite, acid clay), talc (for example, talc, pyrophyllite, etc.), silica (for example, diatomaceous earth, silica sand, mica, white carbon [containing fine powdered silicon, hydrous silicic acid) Some dispersed silicic acid products contain calcium silicate as the main component.]) Natural minerals such as activated carbon, sulfur powder, pumice, calcined diatomaceous earth, attapulgite and zeolite, brick ground, fly ash, sand, clay, barium sulfate, calcium carbonate, calcium sulfate, calcium phosphate, aluminum silicate, magnesium aluminum silicate, Use inorganic mineral powders such as smectite, bentonite, hectorite, synthetic hydrous silicic acid, plastic carriers such as polyethylene, polypropylene, polyvinylidene chloride, etc., chemical fertilizers such as ammonium sulfate, ammonium phosphate, ammonium nitrate, urea, ammonium sulfate, compost, etc. Can do.

Among them, the binder is preferably a compound having thixotropic properties. The thixotropy means the property that the viscosity of the intermediate substance between a plastic solid such as a gel and a non-Newtonian liquid such as a sol changes with time. Specifically, when the shear stress is continued, the viscosity gradually decreases and becomes liquid, and when it is stopped, the viscosity gradually increases and finally becomes solid. Specific examples of the compound having thixotropic properties include viscosity including kaolin, bentonite and the like. If it has thixotropic properties, it becomes possible to uniformly disperse the binder in the kneading step to be described later, and it is possible to maintain high stability after kneading.
Among the compounds having thixotropic properties, bentonite is preferably used as the binder. Bentonite is easily available, and a granular herbicide can be produced at low cost.

  The weight ratio of the binder in the granular herbicide is preferably 10% by mass to 30% by mass, and more preferably 10% by mass to 20% by mass. When the amount of the binder is too small, the mechanical stability of the granular herbicide is lowered, and it becomes easy to break by impact. That is, it becomes difficult to maintain the weeding performance for a long time. On the other hand, when the amount of the binder is too large, the mechanical stability is increased, but the herbicidal effect is poor. Since the binder does not have a herbicidal effect, the herbicidal performance decreases as the amount of the binder increases. That is, it is not efficient because many granular herbicides are required for the same area.

  The weight ratio of sodium chlorate in the granular herbicide is preferably 40% by mass to 60% by mass, and more preferably 45% by mass to 55% by mass. Since sodium chlorate has a high herbicidal effect, the weight ratio of sodium chlorate in the granular herbicide is the main component of the granular herbicide, so that the overall herbicidal performance of the granular herbicide is maintained. Can do.

  The weight ratio of sodium bicarbonate in the granular herbicide is preferably 25% by mass to 40% by mass, and more preferably 30% by mass to 40% by mass. Sodium hydrogen carbonate exhibits high combustion resistance. Therefore, the explosion-proof property and fire resistance of a granular herbicide can be improved because the weight ratio of sodium hydrogencarbonate in a granular herbicide becomes the said range.

(About the shape of the granules)
As for the granular herbicide of this invention, the granule of 80 mass% or more of the whole is substantially spherical shape. The substantially spherical shape means that the longest diameter in the granule (hereinafter referred to as “longest diameter”) and the shortest diameter in the granule (hereinafter referred to as “shortest diameter”) are the longest diameter / shortest diameter = 1.0-1. Refers to a shape in the range of 5.
Although the reason why the granule is approximately spherical increases the stability against flammability and explosiveness is unknown, it is thought to be due to the change in the volume to surface area ratio. Further, if the granule is substantially spherical, the force is dispersed against a physical impact, so that the physical stability is also increased. That is, it is possible to suppress the granulation from being broken in every process such as transportation, storage, and production, and maintain the sustainability of a predetermined herbicidal component.
Conventionally, the shape of the granule is formed into a bowl shape if nothing is done. Therefore, in order to make it substantially spherical, it is necessary to perform a step of changing the bowl-shaped granules into a substantially spherical shape, which leads to an increase in the number of steps. Therefore, making the shape into the shape is not easily conceived by those skilled in the art based on ordinary knowledge, and it is very important in the present invention that the shape is made even if the number of steps is increased. It is.

(Regarding the particle size of granules)
The granular herbicide of the present invention has a particle size of 2 mm or more. Here, “the particle size of the granule is 2 mm or more” means a granule having a mesh size of 2 mm (meaning a mesh sieve defined in “Standard Sieve” of Japanese Industrial Standard Z8801 and having a mesh size of 2 mm). Means that when passing through the mesh sieve in 30 minutes, it is 10% by mass or less. This test method is a test method for determining whether or not it falls under the category of No. 1 of the Ministerial Ordinance on the Testing and Properties of Dangerous Goods (Ministerial Ordinance No. 1 of February 17, 1989). is there.
If the particle size of the granular herbicide is 2 mm or more, the herbicidal effect can be maintained for a long time. In addition, since the shape of the herbicide is almost spherical, the granular herbicide is difficult to break, and when the granular herbicide is dispersed in the field, the herbicidal effect of each granular herbicide can be made constant. it can.
Conventionally, it has been common to reduce the size of granular herbicides in order to increase dispersibility. In addition, the larger the size, the longer it takes to dry the granular herbicide and the lower the productivity. Therefore, increasing the size is not easily conceived by those skilled in the art based on ordinary knowledge. That is, it is a very important point in the present invention that the size is increased even if it is contrary to the conventional directionality and the sacrifice of productivity is sacrificed.

(Method for producing granular herbicide)
The method for producing a granular herbicide according to the present invention includes a kneading step of adding water to a mixture containing sodium chlorate, sodium bicarbonate, and a binder, kneading the mixture, extruding the mixed mixture, An extruding step to form, a granulating step for granulating the shape of the pellet so as to satisfy the longest diameter / shortest diameter = 1.0 to 1.5, and a classification step for dividing the granulated granule into sizes of 2 mm or more And a drying step of drying the classified granules.

  FIG. 1 is a schematic view schematically showing a method for producing a granular herbicide according to one embodiment of the present invention. First, as shown in FIG. 1, sodium chlorate, sodium bicarbonate, and a binder are mixed. Since the ratio at this time becomes substantially the same ratio as the granular herbicide to be formed, it can be in the same range as the component ratio of each component in the description of the granular herbicide described above.

  The mixed mixture is transferred to a tank called hopper 1 and further water is added. The water added at this time is preferably 7/100 to 20/100 based on the total weight of the mixture. If the amount of water is too small, the viscosity of the mixture is too high and it is difficult to efficiently perform the kneading operation. Moreover, the size of the pellet obtained in the extrusion process described later is also reduced. This is because when the moisture content of the mixture extruded during extrusion is small, the mixture becomes coarse, and the timing at which the mixture falls under its own weight in the extrusion process described later is accelerated. In addition, since the obtained pellets are low in moisture, the pellets are likely to collapse, and the pellets may collapse during the work process, resulting in a reduction in size. On the other hand, if the amount of water is too large, the viscosity is too low, and it becomes difficult for the pellets obtained in the extrusion process to maintain a predetermined shape. When there is much moisture, the timing at which the mixture falls due to its own weight is delayed, and the ratio of the longest diameter to the shortest diameter of the resulting pellet increases. Therefore, it becomes difficult to granulate into a predetermined shape in the granulation process described later. Even if the shape can be granulated, the granulation process takes time. Furthermore, the timing at which the mixture falls by its own weight is delayed, that is, the total amount (total volume, total weight) of the resulting pellets increases, and the particles after granulation become very large. It is preferable from the viewpoint of safety that the particles become large, but it is not preferable from the viewpoint of workability during the granulation process and usability during use.

  Next, the kneaded mixture is extruded with a predetermined diameter through the discharge port 2. When the extruded pellet 3 is discharged to a certain length, it falls down due to its own weight. Therefore, the pellet 3 obtained is bowl-shaped, and the longest diameter / shortest diameter is often more than 1.5.

  At this time, the extrusion speed in the extrusion step is preferably 300 cm / sec to 450 cm / sec, more preferably 320 cm / sec to 400 cm / sec, and further preferably 342 cm / sec to 378 cm / sec. . By setting the extrusion speed within the range, the pellet shape can be set to an appropriate density and size. If the extrusion speed is too high, the kneaded substance may be extruded in a state containing a large amount of air, etc., and the density of the pellet will be low and it will be easy to crack. If the extrusion speed is too slow, the production efficiency is lowered.

The obtained pellet 3 is granulated so as to satisfy the longest diameter / shortest diameter = 1.0 to 1.5. Examples of the granulation method include a method using a commercially available granulator. As the particle sizer, a Dalton Malmerizer (registered trademark) or the like can be used.
In the conventional granular herbicide, since the shape is not particularly important, the granulation step is not included. On the other hand, in the present invention, by including a granulation step, stability against combustibility and explosiveness and stability against physical force can be increased. That is, it is possible to provide a granular herbicide having excellent stability and capable of maintaining herbicidal performance for a long time. As described above, adding a process that has not been heretofore may lead to a decrease in production efficiency, and therefore it is not easily conceived by those skilled in the art based on ordinary knowledge.
The granulation process does not necessarily have to be performed separately from the extrusion process for forming the pellets and the drying process described later. For example, an operation substantially corresponding to the granulation process is performed in the extrusion process or the drying process. The granule shape may be granulated.

  Next, the granulated granule is classified into a size of 2 mm or more using a sieve 4 having a mesh. The classification process is, for example, putting a set of granules into a mesh sieve having a mesh opening of 2 mm (a mesh sieve defined in the “standard sieve” of Japanese Industrial Standard Z8801 and having a mesh opening of 2 mm), and rotating 160 times per minute This can be done by shaking for 30 minutes. As shown in FIG. 1, those having a granule size of 2 mm or less are screened from the mesh gaps, and therefore can be classified.

By drying the granules obtained at the end, a granular herbicide having a particle size of 2 mm or more and satisfying the longest diameter / shortest diameter = 1.0 to 1.5 can be obtained.
Since the obtained granular herbicide has the size and shape, the herbicidal effect can be maintained for a long time.
In the drying process, since the size of the granular herbicide is large, it takes time to dry the granular herbicide to the inside, and the productivity is lowered. Therefore, increasing the size is not easily conceived by those skilled in the art based on ordinary knowledge.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Can be modified or changed.

  Hereinafter, the effects of the present invention will be made clearer by examples. In addition, this invention is not limited to a following example, In the range which does not change the summary, it can change suitably and can implement.

Example 1
Sodium chlorate, sodium bicarbonate (sodium bicarbonate), and bentonite were mixed at a weight ratio of 50:37:13. Water was further added to the mixed mixture 100 in a weight ratio of 9, and the mixture was homogenized by a kneading step. The kneaded substance was passed through an extruder and discharged from the discharge port to produce a pellet. At that time, in order to produce a uniform pellet, the diameter of the discharge port was set to 2.5 mm. The pellets discharged from the discharge port were further put into a Malmerizer (Dalton: registered trademark) and granulated. And the granulated granule was applied to 190 degreeC dryer, the moisture content was dried to 1.0% or less, and the granular herbicide was obtained.

(Example 2)
Example 2 is different from Example 1 in that the ratio of sodium bicarbonate and bentonite was changed. Specifically, sodium chlorate, sodium bicarbonate (sodium bicarbonate), and bentonite were mixed at a weight ratio of 50:30:20. Water was further added to the mixed mixture 100 in a weight ratio of 9, and the mixture was homogenized by a kneading step. The kneaded substance was passed through an extruder and discharged from the discharge port to produce a pellet. At that time, in order to produce a uniform pellet, the diameter of the discharge port was set to 2.5 mm. The pellets discharged from the discharge port were further put into a Malmerizer (Dalton: registered trademark) and granulated. And the granulated granule was applied to 190 degreeC dryer, the moisture content was dried to 1.0% or less, and the granular herbicide was obtained.

(Example 3)
Example 3 differs from Example 2 in that the amount of water during kneading was changed. Specifically, water was further added to the mixed mixture 100 in a weight ratio of 12, and a kneading step was performed to make uniform. The other points were the same as in Example 2.

(Comparative Example 1)
Sodium chlorate, sodium bicarbonate (sodium bicarbonate), and bentonite were mixed at a weight ratio of 50:30:20. Water was further added to the mixed mixture 100 in a weight ratio of 6, and a kneading step was performed to make uniform. The kneaded substance was passed through an extruder and discharged from the discharge port to produce a pellet. At that time, in order to produce a uniform pellet, the diameter of the outlet was set to 2.0 mm. The pellets discharged from the discharge port were further put into a Malmerizer (Dalton: registered trademark) and granulated. And the granulated granule was applied to 190 degreeC dryer, the moisture content was dried to 1.0% or less, and the granular herbicide was obtained.

(Comparative Example 2)
The comparative example 2 is different from the comparative example 1 in that the granulation process is not performed and the water content at the time of kneading is changed. Specifically, the water content during kneading was set to 9. The other points were the same as in Comparative Example 1.

(Comparative Example 3)
Comparative Example 3 differs from Comparative Example 1 in that the granulation process is not performed. The other points were the same as in Comparative Example 1.

(Evaluation of granules)
・ Measuring method of particle size Put a set of granules into a mesh sieve with a mesh opening size of 2 mm (a mesh sieve specified in the “standard sieve” of the Japanese Industrial Standard Z8801 and having a mesh size of 2 mm), and rotate 160 When the number of particles falling below the sieve was 10% by mass or less, the particle diameter of the granules was 2 mm or more.
-Particle shape 10 g of the obtained granular herbicide was taken, and the longest diameter and the shortest diameter of each particle were measured by visual observation using a ruler. Particles that fall within the range of longest diameter / shortest diameter = 1 to 1.5 were regarded as approximately spherical, and the mass% of particles corresponding to approximately spherical out of the total amount was measured.
・ Underwater disintegration Underwater disintegration is the measurement of the disintegration of grains in water, and the measuring means is a method based on the notice of the Director of Production, Ministry of Agriculture, Forestry and Fisheries, No.13 Production No. 3987, dated January 10, 2002. It was measured. Specifically, 50 ml of water (3 hardness water) is placed in a glass petri dish having a diameter of 9 cm and allowed to stand, and 5 sample granules are charged so as to be substantially uniform. The time from immediately after the injection until the test granule did not retain its original shape was measured.
Here, the 3 hardness water is obtained by dissolving 0.3077 g of calcium carbonate and 0.092 g of magnesium oxide in a small amount of diluted hydrochloric acid, evaporating to dryness on a sand bath to remove hydrochloric acid, and diluting to 1 L of water. Since this water has a hardness of 30 degrees, it is possible to obtain 3 hardness water by diluting 10 times in use.

  Table 1 summarizes the measurement results of the granular herbicides of Examples 1 to 3 and Comparative Examples 1 to 3 based on the above evaluation indices. In Table 1, “Judgment as to whether or not substantially spherical”, “◯” indicates a substantially spherical shape, and “x” indicates that it is not a substantially spherical shape.

In the granular herbicides obtained in Examples 1 to 3, the shape of 80% by mass or more satisfies the longest diameter / shortest diameter = 1.0 to 1.5, and the particle diameter is 2 mm or more. Although the comparative example 1 is substantially spherical, the size is 2 mm or less. In Comparative Example 2, the particle size is 2 mm or more, but the particle shape is not substantially spherical. In Comparative Example 3, the particle diameter is 2 mm or less, and the particle diameter is not substantially spherical.
Moreover, when Example 2 and Example 3, or Comparative Example 2 and Comparative Example 3 are compared, it turns out that the shape of the particle | grains obtained by the water content at the time of kneading | mixing increasing becomes large. It can also be seen that if the shape is substantially spherical, the disintegration in water is moderate and the weeding performance can be maintained for a long time.

(Evaluation based on the Fire Service Act)
About the granular herbicides obtained in Examples 1 to 3 and Comparative Examples 1 to 3, each of the tests based on the description of the ministerial ordinance on the dangerous goods test and properties (Ministry of Autonomy Ordinance No. 1 of February 17, 1989) The test was conducted. The dangerous substance determination flowchart is described in FIG. “Powder” in FIG. 2 is synonymous with particles of 2 mm or more.

-Evaluation of the herbicide of Example 1 (1) When a large-scale combustion test was conducted using potassium perchlorate as a standard substance, the result was nonflammable.
(2) When the iron pipe test was conducted, the result was unexplosive.
The herbicides of Examples 1 to 3 are solids that do not fall under “powder” as defined in the Ministerial Ordinance. In addition, considering the test results of (1) and (2) above, the herbicide of Example 1 corresponds to a dangerous substance as defined in the Fire Service Law. Therefore, it is a stable compound from the point of combustibility and explosiveness, and handling of the abandonment property is easy.
The granular herbicides of Examples 2 and 3 were also tested in the same manner as in Example 1, and similar results were obtained.

-Evaluation of the herbicide of Comparative Examples 1-3 The evaluation based on the fire fighting law of each herbicide of Comparative Examples 1-3 was performed. First, Comparative Example 1 was examined as follows.
(1) When a combustion test using potassium bromate as a standard substance was carried out, the result was a combustion time of 126 seconds, which was longer than the combustion time (38 seconds) of the standard substance.
(2) When a combustion test using potassium perchlorate as a standard substance was carried out, the result was a combustion time of 69 seconds, which was less than the combustion time (208 seconds) of the standard substance.
(3) When the falling ball-type impact sensitivity test was measured 10 times with a 50% potassium chlorate explosion, all were unexplosive.
(4) When the falling ball type impact sensitivity test was measured 10 times with 50% potassium nitrate explosion, all were explosions.
The herbicide of Comparative Example 1 is a solid corresponding to “powder” as defined in the Ministerial Ordinance. Considering the results of (1) to (4) above, the herbicide of Comparative Example 1 corresponds to the second type oxidizable solid as defined in the Fire Service Law. Therefore, compared with the herbicide of Example 1, it is unstable in terms of flame retardancy and explosiveness, and various restrictions on handling of legal properties occur.

Next, the following test was performed on the herbicide of Comparative Example 2.
(1) A mass combustion test using potassium perchlorate as a standard substance was conducted, and the result was non-combustible.
(2) When the iron pipe test was conducted, the result was an explosion.
The herbicide of Comparative Example 2 is a solid that does not correspond to the “powder” defined in the Ministerial Ordinance. Considering the results of the above (1) and (2), the herbicide of Comparative Example 2 corresponds to the third kind oxidizable solid defined in the Fire Service Law. Therefore, compared with the herbicide of Example 1, it is unstable in terms of flame retardancy and explosiveness, and various restrictions on handling of legal properties occur.

Finally, the following test was performed for Comparative Example 3.
(1) When a combustion test using potassium bromate as a standard substance was carried out, the result was a combustion time of 126 seconds, which was longer than the combustion time (38 seconds) of the standard substance.
(2) When a combustion test using potassium perchlorate as a standard substance was carried out, the result was a combustion time of 69 seconds, which was less than the combustion time (208 seconds) of the standard substance.
(3) When the falling ball-type impact sensitivity test was measured 10 times with a 50% potassium chlorate explosion, all were unexplosive.
(4) When the falling ball type impact sensitivity test was measured 10 times with 50% potassium nitrate explosion, all were explosions.
The herbicide of Comparative Example 3 is a solid corresponding to “powder” as defined in the Ministerial Ordinance. Considering the results of the above (1) to (4), the herbicide of Comparative Example 3 corresponds to the second type oxidizable solid as defined in the Fire Service Law. Therefore, compared with the herbicide of Example 1, it is unstable in terms of flame retardancy and explosiveness, and various restrictions on handling of legal properties occur.

1 ... hopper, 2 ... discharge port, 3 ... pellet, 4 ... sieve

Claims (5)

Including sodium chlorate, sodium bicarbonate, and a binder,
The shape of 80% by mass or more satisfies the longest diameter / shortest diameter = 1.0 to 1.5,
A granular herbicide having a particle size of 2 mm or more.   The granular herbicide according to claim 1, wherein the binder is a compound having thixotropic properties. A kneading step of adding water to a mixture containing sodium chlorate, sodium bicarbonate, and a binder, and kneading the mixture;
Extruding the mixed mixture to form pellets;
A granulation step of granulating the pellet so as to satisfy the longest diameter / shortest diameter = 1.0 to 1.5;
A classification step of dividing the granulated granule into 2 mm or more sizes;
A method for producing a granular herbicide comprising a drying step of drying the classified granules.   The method for producing a granular herbicide according to claim 3, wherein in the kneading step, water having a weight of 7/100 to 20/100 is added to the total weight of the mixture.   The manufacturing method of the granular herbicide in any one of Claim 3 or 4 which sets the extrusion speed in the said extrusion process to 300 cm / sec-450 cm / sec.

Images