JP3795110B2 - Sustained release pheromone formulation - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a sustained-release pheromone preparation that releases a volatile pheromone and suppresses the generation of pests.
[0002]
[Prior art]
The requirement to gradually release volatile drugs and maintain their efficacy for a long time is required, for example, by a communication disruption method that releases pesticides at a constant concentration over a long period of time to suppress the occurrence of pests. . The communication disruption method is a method in which a pheromone having a concentration much higher than that generated by pests is drifted in the field so that males and females do not mate by decreasing the communication ability of knowing and locating individual sexes. In the communication disruption method, a sustained-release pheromone preparation that releases pheromone into the atmosphere is used. Among sustained-release pheromone preparations, a container-enclosed type having a large retention capacity is effective for releasing pheromones for a long period of time.
[0003]
[Problems to be solved by the invention]
JP-B-62-9561, JP-B-2-62522, and JP-B-2-57044 disclose a sustained-release pheromone preparation in which a polymer tubule is filled with a liquid pheromone and both ends of the tubule are closed. Is described. The release rate of pheromone is proportional to the release area (outer surface area) of the preparation and inversely proportional to the wall thickness of the capillary. Therefore, when the outer surface area is fixed, the amount of pheromone released can be controlled by adjusting the wall thickness.
[0004]
It takes 6 to 7 months to control pests with the communication disruption method. For this reason, it is necessary to increase the thickness to suppress the release rate and to release the pheromone for 6 to 7 months or more. However, when the thickness of the thin tube is large, the workability and the processing speed when closing both ends of the thin tube after filling the pheromone are lowered.
[0005]
As a means for suppressing the release rate of pheromone while maintaining the wall thickness, Japanese Patent Application Laid-Open No. 62-258301 describes a method in which a part of the preparation is coated with a substance having poor pheromone permeability. However, the hardly permeable substance may be peeled off due to the low strength of the coating, and the cost for coating is high.
[0006]
The present invention has been made to solve the above-described problems, and provides a sustained-release pheromone preparation that can suppress the release rate of pheromone while maintaining the thickness of the thin tube without performing secondary processing such as coating. For the purpose.
[0007]
[Means for Solving the Problems]
The sustained-release pheromone preparation of the present invention, which has been made to achieve the above object, has a pheromone permeation with an equilibrium swelling ratio of 2 to 10% by weight when the resin is immersed in liquid pheromone 1 and left at 20 ° C. Is a thin tube 2 formed from a mixture of 95 to 60 parts by weight of a conductive resin and 5 to 40 parts by weight of a pheromone hardly permeable fat having an equilibrium swelling ratio of 0.2 to 2% by weight. The thin tubule 2 is filled with the liquid pheromone 1.
[0008]
The pheromone permeable resin is a resin selected from polyethylene, polypropylene, ethylene-vinyl acetate copolymer and ethylene-methacrylate ester copolymer, and the pheromone hardly permeable resin is polyester, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl. A resin selected from alcohol copolymers and partially saponified ethylene-vinyl acetate copolymers is preferred.
[0009]
Particularly preferably, the pheromone permeable resin is selected from polyethylene or ethylene-vinyl acetate copolymer, and the pheromone hardly permeable resin is selected from polyvinyl alcohol, an ethylene-vinyl alcohol copolymer, and a partially saponified product of an ethylene-vinyl acetate copolymer. Combination with resin is good. Combinations other than the above are not preferable because they may not be mixed uniformly during processing.
[0010]
The ethylene-vinyl acetate copolymer preferably has a vinyl acetate content of 3 to 25 mol%.
[0011]
The partially saponified product of the ethylene-vinyl acetate copolymer preferably has a saponification degree of 20 mol% or more.
[0012]
The ethylene-vinyl alcohol copolymer preferably has a vinyl alcohol content of 10 to 60 mol%.
[0013]
The equilibrium swelling ratio of the pheromone permeable resin is preferably 2 to 10% by weight, and the equilibrium swelling ratio of the pheromone hardly permeable resin is preferably 0.2 to 2% by weight. The equilibrium swelling rate here means that the polymer piece absorbs the liquid pheromone 1 when the polymer piece of pheromone permeable resin or pheromone hardly permeable resin is immersed in the liquid pheromone 1 and left at 20 ° C. The amount is expressed as a percentage by weight. When the equilibrium swelling ratio of the pheromone permeable resin is less than 2% by weight, the permeability of the pheromone to the thin tube 2 is too small, so that it is not suitable for a thin tube type pheromone preparation. If it exceeds 10% by weight, the permeability of the pheromone is too large, and even when mixed with a pheromone poorly permeable resin, the permeability does not decrease so much and the release rate is not suppressed. When the equilibrium swell ratio of the pheromone poorly permeable resin is less than 0.2% by weight, the permeability is too small, so that it is not suitable for a capillary type pheromone preparation. If it exceeds 2% by weight, the permeability is too high and the release rate is not suppressed.
[0014]
The thin tube 2 is formed from a mixture of 95 to 60 parts by weight of the pheromone permeable resin and 5 to 40 parts by weight of the pheromone hardly permeable resin. When the permeable resin is less than 60 parts by weight, the strength of the formed thin tube 2 is lowered. When the amount exceeds 95 parts by weight, the permeability is not so low, and the pheromone release rate is not suppressed. The pheromone permeable resin and the pheromone poorly permeable resin must be uniformly mixed.
[0015]
The sustained-release pheromone preparation usually has a pheromone amount of 100 to 500 mg per preparation and an effective release period of 3 to 7 months. In order to release 100 to 500 mg of pheromone for 3 to 7 months, it is preferable to set the inner diameter of the thin tube 2 to 0.4 to 2 mm and the wall thickness to 0.2 to 0.8 mm. When the wall thickness is less than 0.2 mm, the strength of the thin tube 2 becomes low, and it becomes difficult to perform processing such as heat sealing and ultrasonic sealing when both ends are closed. When it is larger than 0.8 mm, the thin tube 2 becomes rigid, and the workability during the shaping process and the workability when closing both ends are significantly reduced.
[0016]
[Action]
A liquid pheromone 1 filled in a thin tube 2 composed of a pheromone permeable resin having an equilibrium swelling rate of 2 to 10% by weight and a pheromone poorly permeable fat having an equilibrium swelling rate of 0.2 to 2% by weight is placed inside the wall of the thin tube 2. It penetrates and evaporates from the outer wall to the atmosphere. The pheromone release rate is determined by three factors: (1) the solubility of the pheromone on the wall, (2) the diffusion rate of the pheromone in the wall, and (3) the rate of evaporation of the pheromone into the atmosphere.
[0017]
The sustained-release pheromone preparation of the present invention (1) controls the release rate of pheromones by adjusting the solubility of pheromones on the wall surface. By closing both ends of the thin tube 2 and changing the mixing ratio of the pheromone permeable resin and the pheromone poorly permeable resin, the permeability of the pheromone to the wall surface is adjusted, and the pheromone release rate is controlled.
[0018]
【Example】
Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 is a cross-sectional view showing one embodiment of a sustained release pheromone formulation to which the present invention is applied. As shown in the figure, a liquid pheromone 1 is filled in a narrow tube 2 closed at both ends.
[0019]
The sustained-release pheromone preparation is produced as follows. A pheromone permeable resin and a pheromone hardly permeable resin are mixed and melted to obtain a polymer capillary 2 having an inner diameter of 0.4 to 2 mm and an inner diameter of 0.2 to 8 mm by extrusion molding or the like. After filling the thin tube 2 with the liquid pheromone 1, it is sealed at an appropriate interval, and the sealed portion is cut to obtain a sustained release pheromone preparation. As a sealing method, there are a heat seal and an ultrasonic seal.
[0020]
The sustained-release pheromone formulation shown in FIG. 1 was actually produced, and the release rate of pheromone was measured. The experimental example will be described in detail.
[0021]
Example 1
70 parts by weight of a high-density polyethylene resin, which is a pheromone-permeable resin, and 30 parts by weight of an ethylene-vinyl alcohol copolymer resin (vinyl alcohol content: 30 mol%), which is a pheromone-impermeable resin, are mixed and extruded to give an inner diameter of 1.14. A thin tube 2 made of polymer having a thickness of 0.35 mm was obtained. Z8-dodecenyl acetate (Natsuhimeshin's sex pheromone) as liquid pheromone 1 was filled into the thin tube 2 and ultrasonically sealed at intervals of 20 cm. The sealed portion was cut to obtain a polymer capillary-type sustained-release pheromone formulation with both ends closed.
[0022]
(Measurement of pheromone filling amount of sustained release pheromone preparation)
Since the inside diameter of the thin tube 2 is 1.14 mm and the length per one preparation is 20 cm, the volume of the thin tube 2 is 0.20 cm ³ . Since the specific gravity of Z8-dodecenyl acetate is 0.86 g / cm ³ , the filling amount per formulation is calculated to be 172 mg.
[0023]
Both ends of the preparation were cut, dissolved and extracted with n-hexane together with the preparation, and then the amount of pheromone was measured by gas chromatogram. From one formulation, 170 mg of pheromone was detected, which almost coincided with the calculated value.
[0024]
(Measurement of equilibrium swelling ratio of polymer)
Each of the high-density polyethylene and ethylene-vinyl alcohol copolymer resin used for the production of the thin tube 2 was well kneaded with two rolls and then pressed with a press machine to obtain a polymer sheet having a thickness of 0.5 mm. The sheet was cut into a size of 2 × 2 cm to obtain a polymer piece. After measuring the weight of the polymer piece, it was immersed in Z8-dodecenyl acetate and allowed to stand at 20 ° C. After 20 days, the polymer piece was taken out, the surface of the polymer piece was wiped off with filter paper, the weight was measured, and the increase in weight was determined. Thereafter, it was immersed again in Z8-dodecenyl acetate and allowed to stand at 20 ° C. After 10 days (total immersion time of 30 days), the weight increase was determined again. There is no change in the weight increase after 20 days and after 30 days, and it can be determined that equilibrium has been reached. The equilibrium swelling rate of the high density polyethylene was 2.8%. The equilibrium swelling rate of the ethylene-vinyl alcohol copolymer resin was 0.6%.
[0025]
(Measurement of release rate)
The sustained release pheromone preparation was allowed to stand under the conditions of 30 ° C. and a wind speed of 0.5 m / sec, and the release rate was measured by measuring the change with time of weight. As a result, it was found that pheromone was released at a release rate of 0.8 mg / day / piece for 150 days.
[0026]
Comparative Example 1
A high density polyethylene resin was extruded to obtain a polymer thin tube 2 having an inner diameter of 1.14 mm and a wall thickness of 0.35 mm. In the same manner as in Example 1, Z8-dodecenyl acetate was filled into the capillary 2 and sealed at intervals of 20 cm to obtain a sustained-release pheromone formulation with both ends closed.
[0027]
The sustained release pheromone preparation was allowed to stand under conditions of 30 ° C. and a wind speed of 0.5 m / second, and the change in weight with time was measured in the same manner as in Example 1 to measure the release rate of pheromone. As a result, the release rate gradually decreased after 80 days of release at a release rate of 1.5 mg / day / 1. The effective release period was as short as 90 days.
[0028]
【The invention's effect】
As described above in detail, in the sustained-release pheromone preparation of the present invention, the pheromone release rate can be controlled by varying the mixing ratio of the pheromone-permeable resin and the pheromone-impermeable resin within a predetermined range. Since the release rate can be suppressed while keeping the thickness of the thin tube small, it is easy to perform processing when closing both ends of the thin tube. Furthermore, since it becomes moderate hardness, it becomes easy to process at the time of a shaping process.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing one embodiment of a sustained release pheromone formulation to which the present invention is applied.
[Explanation of symbols]
1 is a liquid pheromone, and 2 is a capillary.

Claims (4)

When the resin is immersed in a liquid pheromone and left at 20 ° C., 95-60 parts by weight of the pheromone-permeable resin having an equilibrium swelling ratio of 2-10 wt% and an equilibrium swelling ratio of 0.2-2 wt% A sustained-release pheromone preparation, characterized in that the pheromone is a capillary formed from a mixture of 5 to 40 parts by weight of a poorly permeable pheromone resin, and the liquid pheromone is filled in the capillary closed at both ends. .   The pheromone permeable resin is a resin selected from polyethylene, polypropylene, ethylene-vinyl acetate copolymer and ethylene-methacrylic acid ester copolymer, and the pheromone hardly permeable resin is polyester, polyvinylidene chloride, polyvinyl alcohol, ethylene The sustained-release pheromone preparation according to claim 1, which is a resin selected from a partially saponified product of a vinyl alcohol copolymer and an ethylene-vinyl acetate copolymer.   The pheromone permeable resin is polyethylene or ethylene-vinyl acetate copolymer, and the pheromone hardly permeable resin is selected from polyvinyl alcohol, ethylene-vinyl alcohol copolymer, and partially saponified product of ethylene-vinyl acetate copolymer. The sustained-release pheromone formulation according to claim 1, which is a resin.   The sustained-release pheromone formulation according to any one of claims 1 to 3, wherein the narrow tube has an inner diameter of 0.4 to 2 mm and a wall thickness of 0.2 to 0.8 mm.

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