JPS5926601B2 - Pyrethroid insecticidal composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pyrethroid insecticidal composition, and more particularly to an improvement in an insecticide in which the insecticidal component is heated and volatilized using an electric mosquito repellent or the like.

Methods for exterminating indoor pests such as mosquitoes and flies include methods such as spraying oils, emulsions, aerosols, etc. directly onto the pests or on the floor to kill the pests that come into contact with the applied surface (spraying method), and mosquito coils. , a method of heating an electric mosquito repellent mat or the like to volatilize the insecticidal component (heating volatilization method) is known.

Among these methods, the heating volatilization method is currently widely employed because it releases the insecticidal component over a longer period of time than the spraying method and can maintain its insecticidal efficacy at a high level.

Pyrethroid insecticides are generally used in heating volatilization methods using electric mosquito repellent mats, etc., and the insecticides are absorbed into a mat made of pulp, porous synthetic resin, etc., and the mat is heated at 110 to 200°C. The method used is to heat it to a high temperature to volatilize the insecticidal ingredients.

However, it is impossible to effectively volatilize insecticidal ingredients using this heating volatilization method using electric mosquito repellent mats, and approximately 40% by weight of the insecticidal ingredients absorbed into the mat volatilize within 9 hours from the start of heating. It's just being done.

Furthermore, in this method, the mat exhibits a strong insecticidal effect in the initial short period of time, but after several hours, the insecticidal effect tends to decrease drastically or become almost impossible to exert. Pyrethroid insecticidal ingredients are unstable and susceptible to decomposition, which also poses a problem in the storage stability of the mat.

For this purpose, for example, 2,6-tert-butyl-4
- Attempts have been made to incorporate decomposition inhibitors such as methylphenol into pyrethroid insecticides, but even if these decomposition inhibitors are incorporated, the above-mentioned drawbacks cannot be sufficiently overcome.

Therefore, there is currently a desire for an insecticide that can effectively volatilize insecticidal ingredients from electric mosquito repellent mats and has excellent storage stability.

In view of the current situation, the present inventor has conducted various studies in order to eliminate the above-mentioned drawbacks.

As a result, they discovered that the desired objective could be achieved when a pyrethroid insecticidal component and tocopherol and/or tocopherol acetate were used in combination, leading to the completion of the present invention.

That is, the present invention relates to a pyrethroid insecticidal composition characterized in that the pyrethroid insecticidal component contains tocopherol and acetate ester of hatcopherol.

According to the present invention, the insecticidal component can be volatilized efficiently (increased), and decomposition of the insecticidal component due to heating can be suppressed, and its insecticidal effect can be maintained for a long time of 8 hours or more.

Furthermore, the pyrethroid insecticide according to the present invention has excellent stability during storage, as the insecticidal component in the insecticide does not decompose even after long-term storage.

As the pyrethroid insecticidal component used in the present invention, a wide range of known ones can be used, and a typical example is 3-allyl-2-methylcyclopent-2-ene-4-one-1.
-yl-di-cis, trans-chrysanthemate (trade name: Pinamine, manufactured by Sumitomo Chemical, hereinafter referred to as "allethrin"), 3-allyl-2-methylcyclopent-2-ene -4-one-1-yl-d-cis, trans-chrysanthemate (trade name: Pinaminforte, manufactured by Sumitomo Chemical, hereinafter this compound will be referred to as "Pinaminforte"), 2-methyl-5- Examples include (2-7'lopyl)-3-furylmethel chrysanthemate.

In the present invention, tocopherol and/or acetate ester of tocopherol (tocopherol acetate) is blended with the insecticidal component.

Examples of tocopherol include α-tocopherol, β-tocopherol, γ-tocopherol, and δ-tocopherol.

These tocopherols and their acetate esters may be natural or synthetic.

The blending ratio of tocopherol and/or tocopherol acetate to the insecticidal ingredient is not particularly limited and can be appropriately selected from a wide range depending on the type of insecticidal ingredient used, heating temperature, etc., but usually it is based on 100 parts by weight of the insecticidal ingredient. 1
The amount is 0 to 300 parts by weight, preferably 20 to 100 parts by weight.

If the amount of tocopherol and/or acetate ester of hatcopherol is small, the desired effect will not be exhibited, and conversely, even if the amount is large, no further effect can be expected.

In the present invention, for example, a mixture of a pyrethroid insecticidal component and tocopherol and/or pigeon pherol noacetate is used in pulp, asbestos, porous synthetic resin, mineral powder materials such as diatomaceous earth and clay, and porous magnetic materials such as bisque. A mat for an electric abutment mosquito repellent is obtained by impregnating the mat with the above-described method, and the intended object of the present invention is achieved by heating the mat (usually at 110 to 200° C.).

Alternatively, the above mixture may be formulated into various forms such as paste or cream by conventional means and volatilized on a heating element.

In the present invention, various additives such as a synergist, a decomposition inhibitor, and a repellent may be added depending on various purposes.

Such synergists include piperonyl butoxide, octachlorodipropyl ether, MGK264, cinepirin, etc., and the decomposition inhibitors include 2,6-di-tert.
-Butyl-4-methylphenol (BHT), 2,5-
Geete? Examples of repellents include t-butylhydroquinone and the like, and N-N-diethyl metatoluamide, di-n-butyl succinate, and the like.

Examples are given below to further clarify the present invention.

Example 1 Using allethrin and pinamin forte as insecticidal ingredients, the formulation shown in Table 1 below had a large C1 of 2.2CrfL.
A mat for an electric mosquito repellent is prepared by uniformly absorbing X 3.5CIIlX 0127cIrL onto a pulp board.

Tocopherol and its acetate include (a)d
i-α-tocopherol (manufactured by Wako Tsumugi Pharmaceutical Co., Ltd.), (b) tocopherol acetate (trade name; Buken E Acetate 960, manufactured by Riken Vitamin Oil ■), (C) natural mixed tocopherol 800 (trade name; Buken E Oil 800) , manufactured by Riken Vitamin Oil ■) and (d) Natural Mixed Tocopherol 600
(Trade name: Buken E Oil 600, manufactured by Riken Vitamin Oil)
[These are collectively referred to as tocopherols] were used.

The thus prepared electric mosquito repellent mat (amount of insecticidal ingredient in the mat: A) was placed on a heating element with a surface temperature of 164 to 168°C, and this was placed in a glass cylinder with a diameter of 20 mm and a height of 20 holes. The container was placed in a container, the upper part of which was sealed with a glass plate, and heated with electricity for 3.6 and 9 hours to volatilize the insecticidal components.

3. After 6 and 9 hours have elapsed, the insecticidal components floating in the cylinder are allowed to cool and are condensed and adsorbed on the wall surface, then the cylinder is washed with petroleum ether and the insecticidal components are volatilized by gas chromatography.
Examine B) and determine the volatilization rate (-X100).

The results are shown in Table 2.

The volatilization rate for 0 to 6 hours shown in parentheses in Table 2 was determined by adding the volatilization rate for 0 to 3 hours and the volatilization rate for 3 to 6 hours.

The same applies to the volatilization rate for 0 to 9 hours.

Further, after 3, 6, and 9 hours have elapsed, the amount (C) of the insecticidal component remaining in the mat is measured to determine the remaining amount (-xloO).

Furthermore, the decomposition rate is determined from the volatilization rate and residual rate determined above.

A-(B+C) Decomposition rate (%) = X100☆ The residual rate and decomposition rate thus determined are shown in Table 3.

Tables 2 and 3 show that by blending tocopherols, it is possible to volatilize a large amount of insecticidal ingredients efficiently, and to suppress the thermal decomposition of insecticidal ingredients due to heating, resulting in an excellent volatilization rate even after 9 hours have passed. Recognize.

In particular, Table 2 shows that the volatilization rate for 0 to 3 hours is approximately 10% superior to that of the conventional product, and for 3 to 6 hours and 6 to 9 hours.
The volatilization rate over time is approximately 15% compared to that of conventional products.
It can be seen that the insecticidal effect is even better and the insecticidal effect lasts for a long time.

The volatilization rate from 0 to 9 hours is also extremely high, about 30% or more, compared to that of conventional products.

Example 2 The electric mosquito repellent mat prepared in Example 1 was stored at room temperature, and after 6 months, 12 months, and 24 months, it was extracted with petroleum ether using a Soxhlet machine, and its stability over time was determined by gas chromatography. Test by determining the content of

The results are shown in Table 4.

As is clear from Table 4, the decomposition rate of insecticidal ingredients is 100% even after 24 months in products containing tocopherols.
It has excellent storage stability.

Example 3 The insecticidal efficacy of the electric mosquito repellent mat prepared in Example 1 was examined using the aeration device method [see Collection of Research Papers on Insecticide Efficacy Testing Methods, Vol. 2, Junbe Katsuta, March 1968].

In other words, about 20 adult Culex Culex mosquitoes are released at a surface temperature of 164~
The mat was placed on a heating element at 168°C, and the relationship between time and the number of insects inhibited from falling was observed at a temperature of around 25°C.

This is repeated three times to determine the relative potency.

The results are shown in FIG.

As is clear from Fig. 1, the matte obtained by blending tocopherols with Pinamin Forte (Haruka 6 and ; Bian 8) is 9.
It can be seen that the insecticidal effect is maintained for a long time, showing a high drop inhibition rate even after the passage of time.

On the other hand, after 6 hours, the insecticidal efficacy of the mat (&4) in which Pinamin Forte was absorbed and the mat (A5) in which BHT was added and absorbed by Pinamin Forte decreased rapidly.

[Brief explanation of drawings]

FIG. 1 is a graph showing the insecticidal efficacy of the electric mosquito repellent mat over time measured by the method described in Example 3.

Claims (1)

[Claims] 1. A pyrethroid insecticidal composition comprising tocopherol and/or tocopherol acetate as a pyrethroid insecticidal ingredient.