JPH01207202A - Testing method for hydrated silicic acid for pesticide carriers - Google Patents

Abstract

PURPOSE:To determine the suitability of a hydrated silicic acid as a carrier for agricultural chemicals, by measuring the pore volume of the hydrated silicic acid, thereby judging the oil absorption, adsorption rate of the technical product of agricultural chemical, retainability of the technical product in crushing, etc. CONSTITUTION:The quality of a hydrated silicic acid as a carrier for agricultural chemical is determined by measuring the pore volume of the acid. Hydrated silicic acid powder having excellent quality required as a carrier for agricultural chemical has a pore size distribution wherein the volume of porous having pore radius of 75-100Angstrom accounts for >=45% of the volume of pores having pore radius of 75-150Angstrom . A hydrated silicic acid satisfying the above pore radius distribution enables the increase of the compounding amount of the agricultural chemical and remarkably improves the retainability of the agricultural chemical in crushing.

Description

[Detailed description of the invention] The present invention relates to a method for testing hydrated silicic acid for agricultural chemical carriers.

Pesticides may be manufactured in the form of powders, granules, wettable powders, etc. depending on the properties of the pesticide raw material or the purpose of use.

Conventionally, oil absorption has been used as a criterion for determining the superiority of agricultural chemical carriers, and those with higher oil absorption have been considered to be superior as agricultural chemical carriers. As pesticide carriers, inorganic compounds with a large oil absorption capacity, such as powdered hydrated silicic acid, diatoms, etc., are generally used.

Particularly recently, powdered hydrated silicic acid has attracted attention as a pesticide carrier because of its large oil absorption compared to other inorganic compounds. However, there are many types of powdered hydrated silicic acid depending on raw materials and manufacturing methods, and even powdered hydrated silicic acid with a large oil absorption capacity is not necessarily satisfactory as an agricultural chemical carrier. That is, the quality of powdered hydrated silicic acid required for agricultural chemical carriers cannot be judged simply by the amount of oil absorption, and there are no clear criteria for judgment.

Therefore, the present invention clarifies the criteria for inspecting the quality of hydrated silicic acid for agricultural chemical carriers, and proposes a method for inspecting the hydrated silicic acid.

That is, the present invention is a method for testing hydrated silicic acid for agricultural chemical carriers, which comprises measuring the pore volume of the hydrated silicic acid when testing the quality of hydrated silicic acid for agricultural chemical carriers.

The pore size distribution and pore radius referred to in the present invention are those measured by a mercury porosimeter method and calculated using the following formula.

(However, r is the pore radius and P is the pressure.) For the above pore distribution and calculation method of the pore radius, see, for example, "Powder It is sufficient to follow the explanation in "Illustrated Guide to Physical Properties", pages 116 to 117 (published on May 1, 1975). Moreover, the pore volume refers to the volume occupied by pores smaller than a specific pore.

As mentioned above, various types of powdered hydrated silicic acid can be obtained depending on the types of raw materials and manufacturing methods.

Furthermore, the oil absorption amount of the powdered hydrated silicic acid can be increased as necessary. However, even if powdered hydrated silicic acid has a large oil absorption capacity, its quality as an agricultural chemical carrier is rarely satisfied as described above. As a result of various statistical experiments, the present inventor has determined that handling, oil absorption rate, agricultural chemical retention power during crushing, etc. are determined by the volume occupied by specific pores in the pore size distribution of powdered hydrated silicic acid and its It was confirmed that it is determined by the ratio. Therefore, the quality of hydrated silicic acid as a pesticide carrier can be tested by measuring the pore volume of the hydrated silicic acid.

That is, the quality of powdered hydrated silicic acid required as a pesticide carrier is determined by the pore size distribution of powdered hydrated silicic acid, especially the pore radius of 75 to 75 mm.
150 Volume occupied by human pores and pore radius 75 people ~ 10
0 and the volume occupied by human pores. Of course, as mentioned above, the absolute conditions required for a pesticide carrier are that the amount of adsorption of the active ingredient is large (and the rate of oil absorption of the active ingredient is fast).In this sense, a carrier with a small oil absorption cannot be used; Pore radius of distribution: 10,000
The volume occupied by the pores of Å or less is preferably 2.5 CG/g or more, preferably 2.7 CC/g or more.

In addition, in order to increase the rate of adsorption of agricultural chemical ingredients onto carriers, it is necessary that the volume occupied by pores with a pore radius of 75 to 150 people in the pore size distribution is 0.6 CC/g or more. . In the above pore size distribution, the volume occupied by pores with a pore radius of 75 to 150 people is preferably as large as the above value;
For example, 0.7CG/g or more, preferably 0.8CG/g
It is preferable to choose one with a value of 100 g or more. However, it is industrially difficult to produce a material in which the volume occupied by pores with a pore radius of 75 to 150 humans is extremely large in the pore size distribution, and with the current technology, a product of about 2 CG/g can be obtained industrially. This would be the upper limit. On the other hand, the pore radius of the linear pore diameter distribution is 7.
If the volume occupied by the pores of less than 5 people has a pore radius of 75 to 150 people and the volume occupied by the pores of less than 5 people is 0.6 CC/g or more, the adsorption of commonly used pesticide ingredients is surprisingly small. According to confirmation, the amount of active pesticide adsorbed into pores with a pore radius of less than 75 mm is 2 times the volume occupied by the pores with a pore radius of less than 75 mm.
It is 5% or less, and the maximum is about 40%. Therefore, compared to the volume occupied by pores with a pore radius of 75 to 150 mm, it can be said that the volume occupied by pores with a pore radius of less than 75 mm does not affect the quality of the agricultural chemical carrier.

Powdered hydrated silicic acid, which has the excellent quality required as a pesticide carrier, has a pore size distribution in which the volume occupied by pores with a pore radius of 75 to 100 mm is occupied by pores with a pore radius of 75 to 150 mm. It occupies more than 45% of the volume.

Eiwa-containing silicic acid having a volume occupied by pores with a pore radius of 75 to 150 pores of 0.60 C/g or more in the pore size distribution has an extremely high oil absorption rate for agricultural chemical raw materials. However, carriers adsorbed with agricultural chemical ingredients are generally pulverized, and if the agricultural chemical ingredients are leached during the pulverization process, this will cause a decisive defect in handling as described above. Moreover, as in recent years, attempts have been made to increase the amount of agricultural chemical ingredients used in agricultural chemical carriers, the defects become more serious. In this sense, the force with which the agricultural chemical substance is held in the carrier during crushing is a major cause as well as the increase in the amount of agricultural chemical used per unit. The factor of body retention is the pore radius of 75 people in the pore size distribution.
It is influenced by the volume occupied by 150 human pores and the ratio of the volume occupied by 75 human pores to 100 human pores within that volume. This finding is a completely surprising phenomenon, but as is clear from the Examples and Comparative Examples described later, it is no exaggeration to say that the above relationship 100% determines the quality of agricultural chemical carriers.

If 45% or more of the volume occupied by pores with a pore radius of 75 to 150 people in the pore distribution is occupied by pores with a pore radius of 75 to 100 people, use the above-mentioned agricultural chemical ingredients. Not only is it possible to increase the amount, but the ability to retain agricultural chemical ingredients during pulverization is significantly improved. However, if the ratio is less than 45%, the holding power of the agricultural chemical raw material during pulverization is small, and it is impossible to increase the amount of the agricultural chemical raw material used.

As is clear from the Examples and Comparative Examples described below, the testing method of the present invention can determine the oil absorption of hydrated silicic acid for agricultural chemical carriers, the adsorption rate of agricultural chemical raw materials, the ability to retain agricultural chemical raw materials during crushing, etc. It has made an immeasurable contribution as a standard for judging the quality of Japanese silicic acid.

EXAMPLES In order to explain the present invention in more detail, Examples and Comparative Examples will be given below, but the present invention is not limited to these Examples.

In addition, the pore size distribution, pore volume, oil absorption rate, and agricultural chemical substance retention ability during crushing of the powdered hydrated silicic acid in Examples and Comparative Examples were measured by the following methods.

Measurement method 1) Pore volume The pore size distribution and its pore volume are determined by CARLOE
1520 type mercury porosimeter (Dilatometer type SM3 manufactured by RBA),
Capillary: 3nφ0.0
It was measured using 7065cffll. In addition, the pore volume is 50 to 150 pores, 75 to 100 pores, and 75 to 1 pore radius.
It was expressed as a volume for 50 people and 50 to 10,000 people.

2) Oil absorption rate Figures 1 and 3 are schematic diagrams showing a method for measuring oil absorption rate. Take the hydrated silicic acid sample in the 32 mesh fluid 1 shown in Fig. 1, and while rubbing it with a brush,
A sample is placed in a container 2 with an open top and a height of 16 t/m and a temperature of 0 m/m up to an angle of repose of 30.

Next, as shown in Figure 2, a crane with a diameter of 120 weighs 51.8 g.
Gently place the watch glass 4 on the watch glass 4, and after 30 seconds, pull up the watch glass 4. Next, as shown in Figure 3, 0.31 t/drop of boiling oil 5 was added onto the compressed sample surface 3, and the time required from the time when the boiling oil and the sample came into contact until all the boiling oil was absorbed into the sample was measured. The oil absorption rate was measured. Note that the measurements were performed indoors at room temperature (20° C.).

3) Pesticide drug substance retention test during crushing Place the hydrated silicic acid sample into an evaporating dish. Boil oil 1
Add 2.5 d dropwise, mix well, and absorb.

The adsorbed sample was passed through a Philips coffee mill (
Grind using HR2170). As the grinding continues, the boiling oil gradually leaches out, and eventually the ground material becomes paste-like and the coffee mill spins idly. The time from the start of the grinding to idle rotation was measured, and this was determined as the agricultural chemical substance retention force (hereinafter sometimes simply abbreviated as holding force) during the grinding.

Example 1 Commercially available sodium silicate (StO2/NazO molar ratio = 3
．． 033iOz26.4%) 7.6m and Na, so,
(NazO1,35%) 37M, water 0.4n (6O
The mixture was placed in an internally heated reaction tank equipped with an rrf stirring blade, and while stirring, 1.95 ml of sulfuric acid (22 g/100 portions) was added over about 10 minutes to perform the first acid addition. After the pressurization is completed, steam is blown into the solution while stirring, and the temperature is increased to 95° C. over 20 minutes.

After raising the temperature, ripening is performed at the same temperature for 7 minutes. After that, neutralization was restarted, and the sulfuric acid 2.68% was added to neutralize the remaining alkali.
m for 90 minutes to adjust the pH of the solution to 5.5-6.
．． The reaction is completed so that the value falls within the range of 5.

Next, this solution was added to the hydrated silicic acid product pl+ of 5 after drying.
．． Adjust the pH to 4.4 so that it is 5 to 6.5.

This solution is filtered and washed with water using a filter press to obtain a filter cake containing hydrated silicic acid. This filter cake is slurried again using a dispersion device to create a highly concentrated silicic acid suspension.The hot air temperature is 400℃, and the rotation of the rotating disk is 6
Spray drying at 000 r, p, m to obtain fine granular hydrated silicic acid. This hydrated silicic acid was crushed and degassed to obtain a product.

Using this product, pore diameter volume, adsorption retention power, and oil absorption rate were measured.

The results are shown in Table 1.

Example 2 In Example 1, the amount of sulfuric acid added in the first stage was changed to 1.75
Hydrated silicic acid was obtained in the same manner as in Example 1 except that the amount of the remaining sulfuric acid added to rrf was changed to 2.95 rrf.

The same tests and measurements as in Example 1 were carried out using this hydrated silicic acid. The results are shown in Table 1.

Example 3 Using the same apparatus as in Example 1, powdered hydrated silicic acid was obtained in the same manner as in Example 2, except that the reaction temperature was changed to 85°C. The same tests and measurements as in Example 1 were also carried out using this hydrated silicic acid. The results are shown in Table 1.

Example 4 Commercially available sodium silicate (StOz'/Na2O molar ratio -3
,05,5iOz: 28.4%) 282- and Na
2SO2(Nan.

1.78%) 1124v and water 594d were placed in a 31 glass container, and while stirring, sulfuric acid (22g/100d) 68
．． iv for about 3 minutes and perform the first stage of acid addition. After sex, external heating is performed using a mantle heater for approximately 2 hours.
The temperature is raised to 95°C in 0 minutes.

After raising the temperature, ripening is performed at the same temperature for 5 minutes. Thereafter, neutralization was resumed, and the sulfuric acid 126d was added to neutralize the remaining alkali.
It takes about 100 minutes to sex the solution, and the pl+ of the solution is 3.5~
4.5 to complete the reaction.

Next, this solution was filtered through a Buchner funnel, washed with water, dried in a microwave oven, and then ground in a coffee mill manufactured by Fili 7PS to obtain powdered hydrated silicic acid. Tests and measurements similar to those in Example 1 were conducted using this hydrated silicic acid. The results are shown in Table 1.

Example 5 Commercially available sodium silicate (SiOz/NagO molar ratio =
3.05.5iOz: 28.4%) 282d and N
azSO, (Nan.

1.78%) 1124d and 594 parts of water were placed in a 3β glass container, and while stirring, sulfuric acid (22g/100t/)7
7.6d was separated for about 3 minutes and the first stage of acid addition was performed.

After sex is completed, external heating is performed using a mantle heater, and the temperature is raised to 70°C in about 20 minutes.

After raising the temperature, ripening is performed at the same temperature for 5 minutes. Thereafter, neutralization is resumed, and in order to neutralize the remaining alkali, the sulfuric acid 116.
5d for about 100 minutes until the pH of the solution was 3.
5 to 4.5 to complete the reaction.

Next, 400 tZ of this reaction solution was put into an autoclave having an internal volume of 500 tf. While stirring the reaction solution in the autoclave with a magnetic cooler, the pressure was increased to 3 kg/cJG in about 30 minutes, and stirring was performed at the same pressure for 2 hours. Thereafter, the pressure is reduced to atmospheric pressure by natural slow cooling. Thereafter, the vaginal autoclave-treated liquid was filtered with a Buchner funnel, washed with water, dried in a microwave oven (home use), and then ground with a Philips coffee mill to obtain powdered hydrated silicic acid. The same tests and measurements as in Example 1 were carried out using this hydrated silicic acid. The results are shown in Table 1.

Comparative Example 1 Using the powdered hydrated silicic acid obtained in Example 1, the retention power of the agricultural chemical raw material was measured. In addition, the measurement method was as follows (3) above in 3) "Pesticide drug substance retention test during pulverization", boil oil and the amount of boiled oil used were the pesticide drug substances listed below and the amounts used as shown in Table 2. It was carried out in the same way. The results were as shown in Table 2.

Type of agricultural chemical used

[Brief explanation of the drawing]

FIGS. 1, 2, and 3 are schematic diagrams showing a method for measuring oil absorption rate, respectively. In the diagram, 1 is a sieve, 2 is a container, and 3
4 indicates a sample, 4 indicates a watch glass, and 5 indicates boiled oil.

Claims (1)

[Claims] A method for testing hydrated silicic acid for agricultural chemical carriers, which comprises measuring the pore volume of the hydrated silicic acid when inspecting the quality of hydrated silicic acid for agricultural chemical carriers.