JPS62188968A - Inspection of hydrated silicic acid for agrochemical use - Google Patents

Abstract

PURPOSE:To enable the decision on the acceptance of nature demanded as agrochemical carrier, by measuring at least one item group selected from those including oil absorption, pore distribution, oil absorbing rate and attachment within a device when inspecting the characteristics of hydrated silicic acid for agrochemical. CONSTITUTION:Powdery hydrated silicic acid with a large oil absorption does not necessarily meet the requirement for characters as agrochemical carrier and also the nature thereof is noticeably affected by the pore size distribution. A better judgement on the acceptance of an agrochemical carrier depends on the addition of other items in inspection such as capacity of pore with a specified diameter, namely, pore capacity and/or oil absorbing rate or attachment to a device such as mixer and crusher. In other words, the acceptance of hydrated silicic acid as agrochemical can be determined by inspecting at least one item group from those including pore size distribution, oil absorbing rate of an agrochemical body, attachment in the mixing and crushing after the adsorption of the agrochemical body in addition to oil absorption.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for testing water-use silicic acid suitable for producing agricultural chemicals in the form of powder powders, water-use pills, and the like.

Pesticides can be divided into powders9 depending on the properties of the agricultural chemical substance or the purpose of use.
It may be manufactured in the form of granules and water conservancies. That is, in general, various types of spreader systems are manufactured by mixing drug substances, i-medicinal carriers, diluents, and other additives. For example, one method for manufacturing powders is to mix the active pharmaceutical ingredient and the carrier for the agricultural chemical in advance, adsorb the active ingredient to the carrier for the agricultural chemical, then crush it, and then add talc, clay, etc. as a diluent. There is a method of mixing and grinding again.

Conventionally, oil absorption has been used as a criterion for determining the superiority or inferiority of carriers for agricultural chemicals, and those with higher oil absorption have been considered to be superior as carriers for agricultural chemicals.

As agricultural carriers, inorganic compounds with high oil absorption, such as powdered hydrated silicic acid and diatoms, are generally used. Especially recently, powdered water-based silicic acid has a large oil absorption capacity compared to other inorganic compounds! ! It is attracting attention as a medicinal carrier. However, powdered water silicic acid is a raw material,
A large number of types exist depending on the H production method.1-Even powdered aqueous silicic acid with a large oil absorption capacity is not necessarily satisfactory as a carrier for agricultural chemicals. In other words, the properties of powdered water-based silicic acid required for agricultural chemical carriers cannot be determined based on the amount of oil absorption, and there are no clear criteria for judgment.

The inventor of the present invention has conducted extensive research based on the conclusion that there are factors other than oil absorption that affect the properties required as a carrier for agricultural chemicals. As a result, we found that the properties of water-using silicic acid were significantly affected by the fine powder distribution, which had not been considered a problem in the past when using powdered water + ■Ri゛・r叡1.
As a result of the C research, it is possible to measure the amount of adhesion inside equipment such as mixers and crushers by measuring the volume occupied by pores of a specific diameter, that is, the pore volume and/or oil absorption rate, in addition to the amount of oil absorption. Through these measurements, they discovered the scale that determines whether or not they have the properties required as a carrier for agricultural chemicals, leading to the completion of the present invention.

That is, when inspecting the properties of hydrated silicic acid for agricultural chemicals, the present invention measures at least 111 that is Δ out of the group consisting of (a) oil absorption, and (b) pore size distribution, oil absorption rate, and amount deposited in the device. I will keep that in mind! & A method for testing hydrated silicic acid for chestnuts.

As mentioned above, powdered water silicic acid is a type of raw material,! Various types of products can be obtained depending on differences such as differences in R 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, it does not necessarily have satisfactory properties as a carrier for agricultural chemicals, as described above. In other words, the total oil absorption of the agricultural chemical ingredient is determined by the amount of oil absorbed by the powdered water-based silicic acid, but water-based silicic acid may adhere to equipment such as mixers and crushers, or block pipes in the equipment. The handling and oil absorption speed of agricultural chemical ingredients are not influenced by the amount of oil absorption.

In the present invention, as a result of various statistical experiments, it was found that the handling and oil absorption rate are mainly determined by the volume occupied by the pore radius of 150°A in the pore size distribution of powdered aqueous silicic acid. It was confirmed that Although the pore size distribution of powdered hydrated silicic acid can be measured by various methods, the pore size distribution referred to in the present invention refers to that measured by a mercury porosimeter method unless otherwise specified. The mercury porosimeter method uses the formula r('p, ) = 7.5 x 10'/P from data measured by a mercury porosimeter.
It is shown by the distribution of pore radius calculated by (Kp/cIIL). (Powder Engineering Research Group/Japan Powder Industry Association, ``Illustrated Guide to Powder Physical Properties'', published by Industrial Technology Center Co., Ltd., p. 116, published on May 1, 1975) Powdered water required as a carrier for the above-mentioned agricultural chemicals The present invention is the first to clarify the phenomenon in which the properties of Japanese silicic acid are affected by the pore size distribution of powdered water-based silicic acid, particularly the volume occupied by pores with a pore radius of 150"A or less. In other words, if the volume occupied by pores with a pore radius of 150°A or less in the pore size distribution of powdered water-based silicic acid is small, even if the powdered water-based silicic acid has a large oil absorption amount, the Q It is unsuitable as a medicinal carrier.In the pore size distribution, the volume occupied by pores with a pore radius of 150'A is 0.5 to 2 cc/, preferably 0.
9-2. It is preferred that Q c,c/i. In general, pores larger than 150°A in the pore size distribution affect the oil absorption amount of agricultural chemical ingredients, but do not affect the oil absorption rate or handling. The smaller the pores are below °A, the greater the effect on the oil absorption rate, but extremely small pores, such as 50
When the temperature is below °A, the physical properties as a carrier for agricultural chemicals are not significantly affected.

Therefore, it is generally sufficient to determine the physical properties of a carrier for agricultural chemicals based on the volume occupied by pores with a pore radius of 50 to 150 mm. Also, 50 to 150°
Since the pores of A can be measured with a mercury porosimeter, it is preferable to use a mercury porosimeter.

Of course, there are also known methods for measuring pores, such as the nitrogen adsorption method and methanol adsorption method, but these methods have large errors when measuring pores of 100"A or more, and cannot measure pores of 100 to 150"A. Since there is a forward direction that cannot be measured accurately, it is preferable not to use Suba except when measuring pores of 100°A or less.

In addition, the criterion for determining the quality of agricultural chemical carriers is the oil absorption rate. The oil absorption rate is expressed as the time it takes for a certain amount of hydrosilicic acid to absorb a certain amount of sample oil. As mentioned above, the oil absorption rate is mainly affected by the volume occupied by small pores in the pore size distribution, especially pores of 1508 or less, so when measured instead of or together with the pore size distribution, it is possible to It is more preferable to judge whether the carrier is good or bad.

Furthermore, in order to judge whether a carrier for agricultural chemicals is good or bad, it is necessary that the handling is favorable.

This handling includes containers such as mixers and crushers.

Inspection can be performed by measuring the amount of water-using silicic acid containing agricultural chemical ingredients adhering to the equipment, that is, the amount of adhesion inside the equipment.

The suitability of hydrated silicic acid as a carrier for agricultural chemicals proposed in the present invention is determined not only by the oil absorption amount of hydrated silicic acid but also by the pore size distribution and The adsorption rate and the Ik drug substance can be determined by examining at least one selected from the group consisting of the amount of adhesion during mixing and pulverization after adsorption.

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, pore size distribution, pore volume, and mixing test of powdered hydrated silicic acid in Examples and Comparative Examples.

The oil absorption rate, apparent specific gravity, oil absorption amount, and fineness were measured by the following methods.

(1) Pore size distribution The pore size distribution and its pore volume are calculated using CARLO
ERBA) 1520 deaf mercury porosimeter (DilaL-Ometer) type 8M
3. Capillary (Cap 1ary): 3m5ZI
0,07065cnf). In addition, the display is indicated by the volume occupied by the pore radius of 50 to 150°A.

(2) Mixing test FIG. 1 is a schematic diagram showing the fc position used in the mixing test.

Powdered hydrated silicic acid sample 5 was placed in a polyurethane container having an internal volume of 5001 and equipped with a rotary stirring blade 2 rotated by a motor as shown in FIG. 1 and an addition port 3 for 20 minutes. lit human t% pesticide active ingredient 2
0117 was added dropwise from the addition port 3 over a period of 9 to 10 minutes, and the mixture was mixed for 30 minutes from the start of the addition using a rotating stirring blade at a rotational speed of 200 r"p"m. After mixing, the sample was transferred to a 14 mesh sieve and divided into sieves to determine the sieve residual weight 1. In addition, the v+ of the sample adhering to the inner wall of the container and the rotating stirring blade was measured and expressed as the amount of adhesion within the apparatus.

(3) Oil absorption rate 2nd TfI-4 Figure 4 is a schematic diagram showing a method for measuring oil absorption rate. 32 me8h The powdered water-use silicic acid sample 5 under the sieve, which was separated by a sieve, was divided into diameters of 7 as shown in Fig. 2.
The sample is placed in a container 4 with an open top and a height of 1,611 m, up to the angle of repose of the sample. Next, as shown in FIG.
A weight 7 was placed on a zero force watch glass 6 to give a total weight of 100y, and a weight was placed on the sample, compressed, and lifted after 15 seconds. Then, as shown in Fig. 4, 2 wLt of boiling oil 8 was dropped onto the surface of the compressed sample, 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. It was measured. Note that the measurements were performed indoors at a temperature of 20"C.

(4) Apparent specific gravity It was carried out according to JISK6220.

(5) Oil absorption amount It was carried out according to JISK6220.

(6) It was carried out according to the official fine-grained pesticide inspection method (using a 300 mesh sieve).

Example Powdered water-based silicic acid was obtained by each of the following manufacturing methods.

Sample 1 Commercially available sodium silicate (5 iOt) was placed in a stirring tank with a 2t baffle plate.
, 30.375vot%, Na, 010.23vot
%, 5t02/NagO molar ratio 3.07) is 810
．． Water was added so that the concentration was 4% and Na and So were 0.9%, making the total volume 1.5 t, and a sodium silicate aqueous solution was prepared.
Keep the temperature of the conditioned liquid at 40 to 45"C while stirring, add 25% of sulfuric acid necessary to neutralize the entire amount of sodium silicate over 5 minutes, and raise the temperature to 85°C in 20 minutes. , and aged for 5 minutes at the same temperature. After aging, neutralization was resumed and the sulfuric acid was added for 100 minutes to remove the remaining sodium silicate, and the reaction was completed when the reaction solution had a pH of 3 to 4. After the reaction is completed, the obtained water-use silicic acid slurry is filtered.

After drying, the 5% water-use silicic acid slurry was washed with water so that the pH thereof was 5 to 6, dried in an apparatus, pulverized to a fineness of 5% or less, and degassed to obtain powdery water-use silicic acid. The same applies to the following samples.

Table 1 shows the physical properties of this powdered hydrated silicic acid.

Sample 2 A similar aqueous sodium silicate solution was prepared using the same apparatus as in Sample 1. While stirring the liquid, increase the temperature to 40~
Maintain the temperature at 45℃, add 30% of sulfuric acid necessary to neutralize the entire amount of sodium silicate over 5 minutes, and raise the temperature to 70℃ for 2 hours.
The temperature was raised in 0 minutes. After raising the temperature, powdered hydrated silicic acid was obtained in the same manner as in Sample 1. Table 1 shows the physical properties of this powdered hydrated silicic acid.

Sample 3 Powdered hydrated silicic acid was obtained in the same manner as Sample 2 except that the addition of sulfuric acid was 35%, the reaction temperature was 80"C, and the drying was instantaneous using a microwave oven. Table 1 shows the physical properties of this powdered hydrated silicic acid.

Sample 4 Powder was produced in the same manner as Sample 3, except that the initial addition of sulfuric acid was 35% of the sulfuric acid required to neutralize the entire amount of sodium silicate, and the heating temperature was 70°C. Irrigated silicic acid was obtained. Table 1 shows the physical properties of this powdered water-use silicic acid.

Regarding the above-mentioned powdered water-based silicic acid, a mixing test was conducted to measure the oil absorption rate and use (hereinafter abbreviated as B-P-M-C) (hereinafter abbreviated as I-B-P) as an agricultural chemical ingredient. went. The results are also shown in Table 1. In addition, the mixing test using ①・B-P was carried out with the addition time of the agricultural chemical raw material being 5 minutes.

For comparison, the oil absorption rate was measured and a mixing test was conducted using B-P-M-C as the agricultural chemical raw material for the commercially available powdered water-based silicic acids shown in Table 2. The results are shown in Table 3.

Table 2 Table 3 From Tables 1 to 3 above, it cannot be said that hydrosilicic acid with a large oil absorption is necessarily good as a LK medicinal carrier, and the oil absorption and pore distribution, especially the pore radius of 150°A or less, are important. The volume occupied by
It is found that it is necessary to evaluate the oil absorption rate and/or the amount of adhesion of hydrous silicic acid containing the agricultural chemical raw material.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the mixing test apparatus, and FIG. 2 is a schematic diagram of the mixing test apparatus. Figures 3 and 4 respectively show schematic diagrams showing the method of measuring oil absorption rate. Also, 1 is a container. 2 is a rotating stirring blade, 3 is an addition 0.4 is a container, 5 is a sample, 6
indicates a clock, 7 indicates a weight, and 8 indicates boiling oil.

Claims (1)

[Scope of Claims] When inspecting the properties of hydrated silicic acid for agricultural chemicals, at least one selected from the group consisting of (a) oil absorption, (b) pore size distribution, oil absorption rate, and amount deposited in the device is measured. A method for testing hydrated silicic acid for agricultural chemicals, which is characterized by: