JPH02196704A - Sustained release of agent - Google Patents

Abstract

PURPOSE:To efficiently release an agent useful as an insecticide for cloth gradually by discharging vapor of 1-ethynyl-2-methyl-2-pentenyl chrysanthemate through a specific resin film or resin sheet. CONSTITUTION:Vapor of 1-ethynyl-2-methyl-2-pentenyl chrysanthemate having excellent insecticidal activity and vapor pressure is passed through a resin film or resin sheet having >=0.001 concentration ratio of the compound of release face based on absorption face to gradually release the compound. A film or sheet having two or more layers is especially preferable as the resin film or resin sheet and a film or sheet having at least one layer with a larger saturated absorption amount at the same temperature than the layer forming the release face is preferably used. Consequently stable sustained release of agent can be attained. An insecticide having excellent prolonged effects can be obtained by this method.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a method for sustained release of a vaporizable insect repellent.

<Prior art and problems to be solved by the invention> 1-ethynyl-2-methyl-2-pentenyl chrysanthemate (hereinafter referred to as the present compound) has excellent insecticidal activity and vapor pressure, It is mainly used as an insect repellent for clothing in the form of so-called insect repellent paper, which is made by impregnating paper with the compound.

However, due to its evaporative properties, it is difficult for this compound to maintain its efficacy over a long period of time, and it is desired to develop a method for efficiently maintaining its efficacy.

Under these circumstances, the inventors of the present invention have conducted intensive studies on how to maintain the efficacy of this compound over a long period of time, and have found that by releasing the vapor of this compound through a specific resin film or sheet, it is possible to efficiently slow down the effect of this compound. The present invention was based on the discovery that release can be achieved.

Means for Solving the Problems> That is, the present invention provides a method for transmitting the present compound through a resin film or resin sheet in which the concentration ratio of the present compound on the absorption surface to the emission surface is 06001 or more. This invention relates to a sustained release method.

In the present invention, empensuline is a specific example of the present compound which is an active ingredient.

In addition, the resin film or resin sheet used in the present invention has a surface that faces the vapor of the compound and absorbs it (absorption surface), and a surface that releases the absorbed vapor of the compound again (release surface). It is necessary that the concentration ratio of the compounds is the above value.

The concentration ratio of the present compound on the absorption surface to the emission surface is 0.
If the resin has a molecular weight of less than 001, the diffusion rate of the present compound becomes slow and an extreme concentration gradient occurs inside the resin film or resin sheet, making it difficult to exhibit a stable sustained release effect.

In the method of the present invention, the resin film or sheet is made of a film or sheet of 2r# or more, and at least one layer thereof has a resin whose saturated absorption amount at the same temperature is larger than the N (release N) forming the release surface. By using a film or sheet having layers, more stable release of the present compound can be achieved, and it is also possible to select the combination of resins forming each layer depending on the intended use.

Specific examples of resin films or resin sheets include low-density polyethylene, medium-density polyethylene, In addition to high-density polyethylene and polypropylene, examples include copolymers of ethylene and monomers having polar groups containing 2 mol% or less of monomers having polar groups, such as ethylene-acetic acid. It can be selected from vinyl copolymers, ethylene-methyl (meth)acrylate copolymers, ethylene-ethyl acrylate copolymers, ethylene-vinyl acetate-methyl (meth)acrylate copolymers, and the like.

In addition, in the case of a film or sheet with two or more layers, if the saturated absorption amount at the same temperature is larger than that of the release layer, stable release will be achieved and the absorption layer can be selected depending on the purpose of use, as shown in Table 1. shows the saturated absorption amount at 20"C,
Examples of the release layer and absorption layer include low-density polyethylene, medium-density polyethylene, high-density polyethylene, polypropylene, etc., as well as copolymers of ethylene and a monomer having a polar group. Ethylene-vinyl acetate copolymer, ethylene-methyl (meth)acrylate copolymer, ethylene-ethyl acrylate copolymer,
It can be selected from ethylene-vinyl acetate-methyl (meth)acrylate copolymer and the like.

In the present invention, antioxidants, ultraviolet absorbers, anti-blocking agents, etc. may be added to the extent that they do not impair the purpose of the present invention by, for example, significantly changing the release rate or internal concentration ratio of the resin to the drug. They can be used together as appropriate.

In addition, in the method of the present invention, as a source of vapor of the present compound, the raw material, a diluted product with a solvent, etc., and a filler, resin, paper, etc. impregnated with these liquids are used.

<Example> An example of the present invention will be shown below, but the present invention is not limited thereto. In addition, the methods for measuring physical quantities in Examples are as follows.

Saturated absorption amount: A sheet-like resin having dimensions of 40 x 10 x 0.5 thickness (unit: mm) was immersed in a chemical at 20°C until saturation was reached, and then calculated using the following formula.

((Xl-X2)/X5) The amount of drug evaporated in Sample No. 5 and Comparative Example 1 was determined by the weight loss after a certain period of time.

In addition, the drug concentration in each resin in Example 1.2 was determined by extraction using a Soxhlet extractor using acetone as a solvent, followed by gas chromatography (GC-7A type manufactured by Shimadzu Corporation, liquid phase DEG 52%, carrier Chromo). s o r
b WAW, 0MC8 treatment, using a 1 m long column with 100-120 meshes).

The amount of drug evaporated in Example 3.4 and Comparative Example 2 was calculated from the remaining amount by quantifying the drug concentration (residual amount) inside the drug dispenser after a certain period of time using the above-mentioned Soxhlet extraction and GC analysis.

<Example 1> Using empensuline, the drug 10. OOg to 50mm
Place in a glass container with an inner diameter. Three sheets of low-density polyethylene film (trade name: Sumikasen F208-0, manufactured by Sumikagaku Kogyo ■), each having a thickness of 30 μm and molded by the inflation method, were stacked together as a resin film, and the above-mentioned glass container was sealed.

This container was left in an atmosphere at 20° C., and the amount of transpiration (weight loss) and film concentration were measured over time. The results of the amounts over time are shown in Table 2.

<Example 2> As a resin film, an ethylene-vinyl acetate copolymer with a thickness of 90 μm (trade name Evatate D20, manufactured by Sumitomo Chemical Co., Ltd.) was used.
11. The same procedure as in Example 1 was carried out except that one sheet of vinyl acetate (1.7 mol %) was used. The results are shown in Table 2.

Comparative Example 1> The same procedure as Example 1 was carried out except that no resin film was used. The results are shown in Table 2.

<Example 3> Using empensuline, 92 parts by weight of ethylene-vinyl acetate copolymer (trade name Evatate H2O20 manufactured by Sumima Kagaku Kogyo@, vinyl acetate 5.4 mol%) and 8 parts by weight of the drug were mixed in a Banbury type crosstalk machine. The mixed wire obtained by kneading with a diameter of 30
It was molded into a disk shape with a thickness of 6 mm.

In addition, low-density polyethylene (trade name: Sumikasen F2O8-0, manufactured by Sumikagaku Kogyo ■) was molded into a film with a thickness of 50 μm by an inflation method.

The above disk-shaped molded body is covered with the above bag-like film (150 mm).
x150 mm), the opening was heat-sealed to obtain a drug dispenser.

This drug dispenser was left in an atmosphere of 20° C., and the amount of transpiration was measured over time. Table 2 shows the amount of drug remaining (mg) over time.

Comparative Example 2> A dispenser was obtained in the same manner as in Example 3 except that no resin film was used. This drug dispenser was left in an atmosphere of 20° C., and the amount of transpiration was measured over time. The results are shown in Table 2.

<Example 4> Using empensuline, calcium carbonate CaC03 (product name: Whiten SSB Blue, manufactured by Shiraishi Calcium@, particle size: 1.
50 pm, oil absorption 34 cc/100 g) and 30 parts by weight of the drug were mixed in a mixer. In addition, polypropylene (manufactured by Sumitomo Chemical Co., Ltd., product name: Sumitomo Noblen FA6)
411) was molded into a film with a thickness of 50 μm using an inflation method. After putting 3 g of the mixture into the bag-like film (100 mm x 100 mm), the opening was heat-sealed to obtain a test piece. 20 pieces of this test piece
The sample was left in an atmosphere of ℃ and the amount of transpiration was measured over time. The remaining drug amount (mg) over time is shown in Table 2.

<Example 5> Low-density polyethylene films of 45 μm each (manufactured by Sumika Kagaku Kogyo ■, product name Sumikasen F2O8) were used as resin films.
Example 1 was carried out in the same manner as in Example 1, except that one two-layer film (total thickness: 90 μm) of ethylene-vinyl acetate copolymer (trade name Evatate H2O11, manufactured by Sumitomo Chemical Co., Ltd.) was used. The results are shown in Table 2.

<Effects of the Invention> According to the method of the present invention, it is possible to sustainably release the present compound over a long period of time, thereby making it possible to develop a long-lasting insect repellent containing the present compound as an active ingredient.

Claims (2)

[Claims] (1) When releasing 1-ethynyl-2-methyl-2-pentenyl chrysanthemate through a resin film or resin sheet, the vapor of 1-ethynyl-2-methyl-2-pentenyl chrysanthemate is released. 1. A method for sustained release of 1-ethynyl-2-methyl-2-pentenyl chrysanthemate, which comprises transmitting the compound through a resin film or resin sheet in which the concentration ratio of the compound on the absorption surface to the absorption surface is 0.001 or more. (2) The resin film or resin sheet is a film or sheet with two or more layers, and at least one of the layers has
2. The sustained release method according to claim 1, which is a film or sheet having a resin layer whose saturated absorption amount at the same temperature is larger than that of the layer forming the release surface.