KR920005558B1 - Controlled release formulation - Google Patents

Abstract

No content.

Description

Release regulator

The present invention relates to release modulators, more particularly release modulators of 5-methyl-1, 2, 4-triazolo (3, 4-b) benzothiazole effective for inhibiting rice blast.

Prevention of rice blasts is a great economic aid to rice cultivation. This is because rice blasts greatly reduce the yield and yield of rice. It is practically very important to protect rice crops from rice blasts, but no fungicides are available to prevent rice blasts. In line with the above requirements, 5-methyl-1, 2, 4-triazolo (3, 4-b) -benzothiazole (hereinafter abbreviated as "tricyclazole") has been developed. Tricyclazole is a penetrant fungicide that inhibits Pyicularia oryzae, the causative agent of rice blasts (US Pat. No. 40,426,411) and is commercially available in Japan and some other Asian countries.

Commercially available tricyclazole formulations provide rapid release of tricyclazole when applied to soil as an aqueous suspension solution, granules, hydrating agents or other forms, resulting in sufficient protection of rice crops for the time necessary to protect the entire rice crop leaf stage. Does not protect against rice blasts. In addition, the commercially available formulations release high concentrations of active ingredients, thus damaging the hair of young rice. Therefore, there is an urgent need for the development of tricyclazole preparations that can control the spindle of tricyclazole for a long time sufficient to protect rice seedlings from rice blasts.

The release modulators according to the invention contain tricyclazole as the active ingredient, polymer as the additional ingredient and a carrier usable agriculturally. The polymers used in the formulations of the present invention have a minimum film forming temperature of about 100 ° C. or less and a water absorption in the range of about 5% to 500%.

As used herein, the term "polymer" refers to both homopolymers and copolymers. The polymers used in the present invention may generally have an average molecular weight ranging from about 500 to 3000,000 and more preferably from about 1,000 to 1,000,000.

Thus, the polymer used should have a minimum film formation temperature of about 100 ° C. or less as described above. The minimum film formation temperature can be measured with instruments that have conventionally been used to measure the minimum film formation temperature of a polymer. If the formulation has a poor polymer membrane, the formulation does not sustain the release of the active ingredient and therefore the release is not properly controlled. Therefore, it is preferable to form a film under dry conditions. If the film is formed in a poor state under the above drying conditions, it is preferable to form the film at a high temperature such that it does not exhibit a detrimental effect on tricyclazole.

As described above, the polymer used in the release controlling agent according to the present invention should be measured for 24 hours using JIS K7209 of the Japanese Standards Committee, and its water absorption should generally be in the range of about 5% to 500%. If the water absorption rate does not reach the minimum limit, the release rate of tricyclazole is too slow to be the required concentration of tricyclazole to be effective in preventing rice blasts, so that the concentration is sufficiently efficient to protect the rice crops from the penetration of rice blasts. A large amount of formulation is required to release the active ingredient. The formulations also tend not to release most of the tricyclazole and thus are not used efficiently. If the water absorption of the polymer exceeds the highest limit, the release of tricyclazole is too fast to properly control the release of tricyclazole. It is therefore undesirable to use polymers whose water absorption cannot be measured due to dissolution or re-dispersion in water.

In the present invention, polymers are used that are capable of crosslinking linearly, crosslinked or with metal ions to the extent that the polymer meets the above-mentioned requirements. The polymer may not be limited to any particular one, but the form of an aqueous emulsion or aqueous solution is most preferred because the form can be easily handled in the preparation of the formulation.

Representative examples of polymers in emulsion form that may be used in the present invention are acriset.^(R)EMN-10X, Acriset^(R)-EMN-20X Acrylic Set^(R)Acrylic emulsion such as -EMN-30X (manufactured by Nippon Shokubai Chemical Industry Co., Ltd.); Sumikaflex^(R)Ethylene vinyl acetate copolymer emulsions such as 400 and 500 (manufactured by Sumitomo Chemical Co., Ltd.); Crehalon (R) vinylidene chloride emulsions such as DO and AO (manufactured by Kureha Chemical Co., Ltd.); Kemipal^(R)Polyolefin emulsions such as A-100 and S-100 (manufactured by Mitsui Petrochemical Co., Ltd.); SMA^(R)Styrene-maleic acid water-soluble resins such as 2625A and 17352 (manufactured by Alco Chemical Co., Ltd.).

The release controlling agent according to the invention is preferably prepared by formulating tricyclazole and at least one of the polymers listed above with an agriculturally usable carrier. The carrier may be inherently absorbent or absorbent. Representative examples of the carrier include limestone, sand, gypsum, volcanic rock powder, and crops such as montrolylonite, attapulgite, kaolin and ball clay, mica, fertilizers, and crops such as soybean meal, ground corn cob and rice. I can lift it. Of these carriers, attapulzide, clay and ground rice bran are preferred. Ball clay is preferred when the inventive formulation is extruded into granules. The choice is made taking into account the availability and price of the carriers. As long as the polymer is present at an effective concentration sufficient to control the release of tricycltazole, the concentration of the tricyclazole and the polymer in the release modulator according to the invention is not critical. Generally speaking, the higher the concentration of the polymer in the formulation, the slower the release rate of the tricyclazole to the periphery. Preferred concentrations of tricyclazole and polymer depend on the composition of the formulation, ie when the formulation contains only tricyclazole and polymer or additionally contains an agriculturally usable carrier. For formulations containing only tricyclazole and polymer in the absence of a carrier, the concentration of tricyclazole is in the range of about 0.1 to 75% by weight (unless otherwise indicated, the above and subsequent figures are based on dry weight). The concentration of polymer is in the range of about 25 to 99.5 weight percent. Preferred concentration ranges are about 1-50% by weight and about 50-99% by weight, respectively.

Release modifiers prepared from three or more components are about 0.1-30% by weight, preferably about 1-20% by weight of tricyclazole, about 10-60% by weight, preferably about 20-60% by weight. It generally contains a polymer in the concentration range and an agriculturally usable carrier in the range of about 20-89.9% by weight, preferably in the range of about 20-79% by weight.

The release controlling agent according to the present invention can be prepared by the following method. The finely divided form of the active ingredient material, preferably a finely divided form of the material, is added to the aqueous emulsion or aqueous solution of the polymer or polymers described above to form a slurry. Particles of the finely divided active material are prepared by milling to the technical level using conventional milling methods such as milling techniques in fluid energy mills. In the examples below, tricyclazole is used which has a particle size such that 99.9% can pass through the 326 mesh screen. The slurry is prepared by adding an agriculturally usable carrier or carriers to a tricyclazole mixture dissolved in an aqueous emulsion or aqueous solution of the polymer or polymers, and then mixing the materials to form a homogeneous mixture. The mixture is then made into granules or other forms of formulations suitable for spraying rice crops to prevent rice blast. In order to make the formulation capable of controlling the release of tricyclazole, it is usually necessary to dry the mixture at high temperatures. In applying heat to the formulation, it is preferable to carry out the drying treatment at a temperature higher than the minimum film forming temperature of the polymer to be used, more preferably at a temperature of about 10 ° C. higher than the minimum film forming temperature.

In the present invention, it is preferred to add tricyclazole and a slurry of the polymer or polymers to known, usable rock bodies or carriers in a known manner using conventional apparatus. Or a carrier may be added to the tricyclazole and the polymer or mixture of polymers. The mixing process can usually be carried out at ambient temperature. Representative types of agitators that can be used for agitation include a skin stirrer, a bonded stirrer, a Hobart stirrer, a mini-tumbler stirrer, a ribbon blender or other similar rotary stirrer.

It is preferable to uniformly mix the required amount of tricyclazole, polymer or polymers and carrier or carriers, and then to dry the mixture at high temperature to form a continuous polymer membrane by accelerating adhesion of the polymer particles. The temperature to be adapted may be changed depending on the type of polymer used, but a temperature higher than the minimum film forming temperature of the polymer is preferred, and it is even more preferable to use a temperature about 10 ° C. higher than the minimum film forming temperature. Applicable temperatures are generally in the range of about 5-180 ° C., more preferably in the range of about 30-125 ° C. In carrying out the drying process it is of course also possible to carry out at a temperature lower than the minimum film-forming temperature of the polymer used first and then at a temperature of about 10 ° C. higher than the minimum film-forming temperature of the same polymer. If the minimum film forming temperature of the polymer used is lower than the ambient temperature, the formulation containing the polymer can be dried under ambient temperature. The type of drying appliance is not critical and is chosen from among those well known in the art. Representative dryers include rotary dryers or ovens that operate under standard or reduced pressure.

Alternatively, the tricyclazole, polymer or polymers and a homogeneous mixture of suitable carriers or carriers may be extruded into pellets, granules or other forms of formulation and then dried. Devices and methods used in such extrusion processes are known. In describing the present invention in detail, it is important to use a suitable type of clay as a carrier for extrusion, and ball clay is generally preferred. However, certain types of clays are not required and can be selected and used according to their usefulness. When using carriers in formulations that do not readily disperse in an aqueous medium, it is preferable to use suitable surface active agents to assist in the dispersion of the prepared granules or other types of formulations in water. The surface active agent and its amount of use are selected according to the properties of the composition components and the ability of the surface active agent to promote dispersion of the formulation in water. For example, when rice bran is used as a carrier, a surface active agent is required to promote dispersion of the preparation in water. Suitable surface active agents are in dry form and may be nonionic, anionic or cationic. Examples of anionic surface active agents are alkyl or aryl sodium sulfonates or sulfonic acids, calcium alkylaryl sulfonates and alkyl alcohol esters of phosphoric acid. Examples of nonionic surface active agents are ethoxylated alkyl phenols, ethers and alcohols, sorbitan esters and ethoxylated sorbitan esters and ethers. Emulsifiers and auxiliaries can also be used as surface active agents. Significant commercially available pharmaceuticals on the market are basically anionic or nonionic crabs. The concentration of the surface active agent in the formulation is generally about 0.01% to 5% by dry weight.

Although the exact mechanism of tricyclazole release control with the inventive formulations is not yet known, it is believed that tricyclazole diffuses from a particular polymer phase into the surrounding aqueous medium. However, it is to be understood that the invention is not limited to the specific form of function that may be performed by the formulations of the invention.

The controlled release formulation according to the present invention can be applied to the site of rice crops by conventional methods. Spreading can be carried out manually or using a machine. As a mechanical device, an instrument applicator can be used that can apply an accurate measurement of the granular formulation to the soil surface. The operator needs to handle the applicator so that the formulation is applied in a uniform amount to the desired application rate per unit area and to the preventive area of the rice crop.

The release control agent according to the present invention is preferably applied to the soil of the standard transplanted mother bed where the hair is planted, and may be sprayed on the paddy paddy. In order to ensure optimal conditions for inhibiting the invention when the formulation is applied to the soil of the transplant bed, it is important to transplant the rice seedlings using a mechanical transplanter. If machine transplantation is not feasible, transplant the soil so that there is soil around the roots of the grafted grafts. This process is useful for the continuous prevention of rice blast during the entire period of the plant growth stage by the presence of tricyclazole in the soil around the mock roots in the transplant bed.

The release controlling agent according to the present invention controls and releases the amount of tricyclazole over a long period of time without causing the concentration of tricyclazole to be too high in the initial stages of rice seedling application. Thus, this formulation has a great advantage in reducing or preventing rice simulated plant toxicity over conventional tricyclazole formulations. Another advantage of the release control agent according to the present invention is that it saves a lot of time and money for rice farmers, because the present formulations, like the conventional formulations that have been used to treat leaf blasts of rice when sprayed on rice seedlings This is because it is not necessary to spray the leaf blast stage frequently.

The following examples illustrate in more detail the unique aspects of the present invention. However, the examples are not intended to limit the present invention to a particular aspect and should not be interpreted as such.

Example 1

EMN-20X(아크릴 유상액, 닛뽕 쇼꾸바이 화학 공업 주식회사 제조) 425g의 혼합 슬러리에 파운드리힐 크림 점토(Foundry Hill Creme Clay, 볼 점포, 스핑크스점토사; 이하에서는 "FHC점토"로 약칭함) 760g을 가하고, 상기 혼합물을 교반기에서 잘 혼합한다. 10분 동안 혼합한 후, 혼합물을 5mm 두께를 갖는 다이스틀을 장치한 실험용 펠릿 밀(mill)을 사용하여 압출시켜 직경 2mm 및 길이 3~7mm의 과립으로 제조한다. 상기 과립들을 40℃에서 24시간 동안 건조시킨다. 본 실시예에서 사용하는 아크리세트

EMN-20X의 최소 막-형성 온도 및 수분 흡수율은 각각 17.5℃ 및 53%이다.40g aerial crushed tricyclazole and acriset

760 g of Foundry Hill Creme Clay (Ball Store, Sphinx Clay, hereinafter abbreviated as "FHC Clay") is mixed with 425 g of EMN-20X (acrylic emulsion, manufactured by Nippon Shokubai Chemical Industry Co., Ltd.). Add and mix the mixture well in a stirrer. After mixing for 10 minutes, the mixture is extruded using an experimental pellet mill equipped with a die having a thickness of 5 mm to prepare granules having a diameter of 2 mm and a length of 3 to 7 mm. The granules are dried at 40 ° C. for 24 hours. Acriset used in this embodiment

The minimum film-forming temperature and moisture absorption of EMN-20X are 17.5 ° C. and 53%, respectively.

EXAMPLES 2-9 AND COMPARATIVE EXAMPLES 1-3

Granules were prepared in the same manner as in Example 1, except that the compositions were prepared as described in Table 2 using the polymers listed in Table 1 below. In Examples 4 and 8, the granules are dried at 100 ° C. for 2 hours.

TABLE 1

Note: *) MFT (Minimum Film-Forming Temperature): MFT is measured using an MFT measuring instrument sold by Nippon Rigaku Industrial Co., Ltd.

**) Water absorption: measured in JIS K7209.

Preparation of Samples: A membrane with an aqueous emulsion or aqueous solution of the polymer to be tested was coated on a Teflon plate to form a membrane having a dry film thickness of 1 mm, and the membrane was dried at room temperature for 2 days and then at 50 ° C. for 24 hours in a thermostat. Let's do it. The Chemipal S-100 membrane is left at room temperature for 1 day and then dried in a thermostat at 100 ° C. for 2 hours.

Measurement of Water Absorption Rate: A 50mm x 50mm sample is immersed in distilled water at 25 ° C for 24 hours, and the water absorption rate is calculated from the following formula.

W ₁ = weight of sample before immersion

W ₂ = weight of sample after immersion

W ₃ = weight of dry sample after immersion

TABLE 2

Experimental Example 1

Slow-release granules of tricyclazole are sprayed on one-third of the surface of a 28 × 28 × 3 cm sowing box in which 18-day-old rice crops are planted. The granules contain about 4% and 8% of active ingredient, respectively. In total, 1.5, 3.0 and 6.0 g of the active ingredient is applied to each sowing box. After 24 hours of spraying, non-sterile soil is filled and watered in a 1-quart 4 inch diameter plastic pot with no drainage holes and the above spraying site is implanted. Water from the sowing box is transplanted into a Dan container and assessed for damage after 14 and 23 days. After 23 days of transplanting, the crops were inoculated with a spore suspension of rice blast bacteria (Pycuricaria Orissae) and incubated for 48 hours in a humid room at 70 ° F (21 ° C). Seven days after inoculation, the percentage of rice blast incidence of rice crops is measured and recorded. Experiments are also conducted for slow-release granules (control granules) formulations that do not contain tricyclazole and control formulations using only water. Tricyclazoles made with 75 WP (hydrating agent containing 75% by weight of active ingredient) are also tested for comparison. The extent of damage to the crops is assessed in the range of 0 to 10, as compared to the control crop without the preparation.

0 = Intact

1-3 = Slightly damaged

4-6 = Medium Damage

7-9 = Severely Damaged

10 = The crop is dead

The experiment was repeated three times and the average of each result is shown in Table 3 below.

TABLE 3

As a result of the above experiments, representative release control formulations according to the present invention cause less damage to crops than the formulations currently on the market and effectively suppress rice blasts.

Experiments were also conducted in an attempt to demonstrate the sustained release properties of the formulations. The following method illustrates the above characteristics: The beer is charged with 3 liters of demineralized water at room temperature. One example of a sustained release granule containing 60 mg of active ingredient is added to the demineralized water so that the concentration when all tricyclazole is released from the granule is 20 ppm. After addition, 1 ml of demineralized water sample is taken from the beaker at different time intervals and the concentration of the active ingredient in the sample is measured. In evaluating several formulations in this experiment, the concentration of the active ingredient in the demineralized water is fixed, then removed by tilting the demineralized water and the residue at the bottom is dried. Subsequently, the concentration of the active ingredient remaining on the residue is measured. Experiments are also made with formulations in the 75% hydrated state for comparison. The results of this experiment are shown in ppm in Table 4 below.

TABLE 4

In particular, when compared to tricyclazole hydrates, where most of the active ingredient is released immediately (within 1 hour), this experiment effectively demonstrates that the present modulator regulates the release rate of the active ingredient over a wide period of time.

Claims (10)

A release modifier containing tricyclazole and a polymer having a water absorption in the range of about 5% to 500% of a minimum film formation temperature of 100 ° C. or less. The formulation of claim 1 wherein the polymer is in the form of an aqueous emulsion. A release modifier comprising tricyclazole, a polymer having a minimum film forming temperature of 100 ° C. or lower, and a water absorption in the range of about 5% to 500%, and a carrier usable agriculturally. The formulation of claim 3, wherein the polymer is in the form of an aqueous emulsion. The formulation of claim 3, wherein the carrier is any one selected from the group consisting of clay, rice bran and limestone. Tricyclazole, and a polymer having a minimum film forming temperature of 100 ° C. or lower and a water absorption in the range of about 5% to 500%; Release modifiers dried at temperatures above the minimum film forming temperature of the polymer. The formulation of claim 6, wherein the polymer is in the form of an aqueous emulsion. Tricyclazole, a polymer having a minimum film forming temperature of 100 ° C. or lower and a water absorption in the range of about 5% to 500%, and a carrier usable agriculturally; A release control agent made by drying at a temperature above the minimum film forming temperature of the polymer. The formulation of claim 8, wherein the polymer is in the form of an aqueous emulsion. The formulation of claim 8, wherein the carrier is any one selected from the group consisting of clay, rice bran and limestone.