JP2736433B2 - Sustained-release pest repellent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a cis-form of p-menthane-3,8-diol and a trans form which have a repellent effect on pests such as mosquitoes, slugs, millipedes, and armyworms. By adjusting the affinity of the mixture obtained by mixing the body in a liquid state at normal temperature and the thermoplastic elastomer as the base material, p-menthane-3,8-
The present invention relates to a pest repellent material capable of gradually evaporating a diol into an external space and repelling the pest for a long time.

[Conventional technology]

Conventional means of controlling pests include: 1. Control by insecticides represented by spray-type insecticides and smokers; 2. Control by capture represented by cockroach traps and electric shock insects; 3.
Control is generally performed by repelling such as insect repellent and sheet-like repellent.

Since mosquitoes transmit various infectious diseases, their control measures are extremely important. They transmit diseases such as malaria and Japanese encephalitis to humans, and cause serious damage to dogs as intermediate hosts of parasites that cause filaria. The mosquito control means include spray-type spraying of a pyrethroid insecticide or an organophosphorus insecticide, control by insecticides found in mosquito coils, etc. containing pyrethroid insecticides as a main component, and attracting mosquitoes by ultraviolet rays. In general, a so-called electric shock insect killer that gives an electric shock and causes death is generally performed. Also, a method of spraying a spray containing a repellent to keep mosquitoes away for a certain period of time has been used.

By the way, it is known that p-menthane-3,8-diol has a repellent effect against pests such as mosquitoes, slugs, millipedes, and armyworms. This p-menthane-3,8-
Diol is a substance having a structural isomer and an optical isomer, and (+)-cis-p-menthane-3,8-diol,
(-)-Cis-p-menthane-3,8-diol, (+)
-Trans-p-menthane-3,8-diol, (-)-
There are four isomers of trans-p-menthane-3,8-diol. The melting point of each of these substances is 57 ° C
〜60 ° C. and is solid at room temperature. However, each of them has volatility even in a solid state at normal temperature, and can exert an effect of repelling against pests such as mosquitoes, slugs, millipedes, and armyworms by the atmosphere. A technique has also been proposed in which the p-menthane-3,8-diol is blended with a thermoplastic elastomer to form a sheet. The following problems remain in the above extermination means.

[Problems to be solved by the invention]

In the case of spray type space sprays that have been used in the past, they do not exert their effect unless mosquitoes come in contact with fine pesticide particles sprayed in the air, so excess It was necessary to spray the amount directly, and there were also problems such as low efficiency and strong unpleasant odor.

In addition, mosquito coils and electric mosquito coils have also been used recently, but these also use heat generated by fire or electricity to cause fine pesticide particles to float in the space, and are used as spray-type spaces. Has the same problems as propellants. Moreover, when used in a kennel, etc., the mosquito coil has a safety problem due to the use of fire, and in the case of an electric mosquito coil, there is a practical complication such as connecting an outlet plug. There is a problem.

In addition, there is a problem that the effect of capturing with the electric shock insecticide can be expected only at night.

In the case of a spray containing a repellent, a remarkable effect can be obtained immediately after the spraying, but the effect lasts only for a short time. If a long-term effect is expected, it is necessary to spray repeatedly.

Further, when p-menthane-3,8-diol used in the present invention is used as a repellent, p-menthane-3,8-diol has volatility even in a solid state at room temperature as described above, The volatilization amount cannot be controlled and it is not efficient. Therefore, as disclosed in Japanese Patent Application No. 63-274662, p-menthane-3,8-diol is blended with a thermoplastic elastomer and the affinity thereof is adjusted to obtain p-menthane-3.
A technique for sustained release of 3,8-diol has been proposed. According to this method, p-menthane-3,8-diol can be continuously released in small amounts within a range having an effect over a long period of time. However, the four isomers of p-menthane-3,8-diol all have a melting point of 57 ° C to 60 ° C and are solid at room temperature. Therefore, p-menthan-3,8
-In order to construct a stable sustained release system of diol, it is desirable to use an appropriate liquid component together so that p-menthane-3,8-diol can form a continuous layer in the base material. was there.

[Means for solving the problem]

As a result of intensive studies to solve the above problems, it has been found that when the cis-form and the trans-form of p-menthane-3,8-diol are mixed at a ratio of 15 to 85%, the mixture becomes liquid. did. The present invention regulates the affinity between p-menthane-3,8-diol and a thermoplastic elastomer by mixing the cis-form and trans-form to form a liquid. The design of the release system was made easier, and by forming this into a pellet, sheet, net, rod, etc.,
An object of the present invention is to provide a pest repellent material capable of repelling pests such as mosquitoes, slugs, millipedes, and beetles for a long period of time simply by laying or hanging.

(Operation)

It is already known that p-menthane-3,8-diol contained in eucalyptus essential oil, which is a natural product, has a repellent effect against insects such as mosquitoes, slugs, millipedes, and armyworm. In particular, the trans form of p-menthane-3,8-diol retains repellent activity even at low concentrations. However, this p-menthane-3,8-diol is a volatile substance, and if used as it is, it cannot be controlled by the volatilization amount and is not efficient. Further, p-menthane-3,8-diol has four types of isomers, each having a melting point of 57%.
It is between 60 ° C and 60 ° C and is solid at room temperature. On the other hand, when considering a sustained release system for a volatile substance, it is easier to design a sustained release system if the volatile substance is a liquid rather than a solid. The present invention provides p-menthan-3,
As a result of intensive studies to make sustained release of 8-diol easier, the inventors discovered that when the cis- and trans-forms of p-menthane-3,8-diol were mixed at a certain ratio, the mixture became liquid, The volatility of p-menthane-3,8-diol is controlled by adjusting the affinity between the thermoplastic elastomer and the p-menthane-3,8-diol which has been made into a liquid by mixing the cis form and the trans form. Has been established that can continuously release a small amount in a range where it is effective over a long period of time.

 Hereinafter, the present invention will be described in detail.

Generally, when a volatile substance is uniformly mixed in a base material, the volatile substance present on the surface of the substance is vaporized into the air according to a vapor pressure inherent to the substance. As a result, the concentration of the volatile substance at the surface and at the center becomes non-uniform, resulting in a concentration gradient. Due to this concentration gradient, the volatile substance existing in the center gradually moves to the surface layer, and then volatilizes into the air. By maintaining such a flow, the volatile substance is continuously vaporized into the air. However, when the volatile substance is a solid, the volatile substance rarely forms a continuous layer in the base material,
Often they are discontinuously dispersed. Therefore, no concentration gradient occurs between the layer surface and the central portion. Therefore, in order to stably release the volatile substance which is solid at room temperature, it is necessary to mix an appropriate liquid substance so that the volatile substance can form a continuous layer in the base material. is there. This allows
Even with the volatile substance which is solid at room temperature, a concentration gradient is generated between the layer surface and the central part as the substance evaporates from the layer surface. Due to this concentration gradient, the volatile substance existing in the center moves to the surface layer through the "road path" of the liquid substance and continuously volatilizes in the air. As described above, even if the substance is solid at room temperature, it is possible to construct a sustained-release system if the substance has sublimability. However, it is self-evident that it is desirable that the repellent itself be liquid, considering the stability of the sustained release system and the ease of constructing the sustained release system as described above.

By the way, p-menthane-3,8-diol is a substance having a structural isomer and an optical isomer, and (+)-cis-
p-menthane-3,8-diol, (-)-cis-p-menthane-3,8-diol, (+)-trans-p-menthane-3,8-diol, (-)-trans-p- There are four isomers of menthan-3,8-diol. Each of these substances has a melting point of 57 ° C. to 60 ° C. and is solid at ordinary temperature. Therefore, it is difficult to use each alone as described above.

Based on this point, as a result of intensive studies to construct a more stable sustained release system, p-menthan-3,8-
It has been discovered that by mixing the cis-form and the trans-form of the diol at a fixed ratio, the mixture becomes liquid. That is, (+)-cis-p-menthane-3,8-diol and (+)-trans-p-menthane-3,8-diol,
(+)-Cis-p-menthane-3,8-diol and (−)
-Trans-p-menthane-3,8-diol, (-)-
Cis-p-menthane-3,8-diol and (+)-trans-p-menthane-3,8-diol, (-)-cis-p
-Menthan-3,8-diol and (-)-trans-p-
It has been found that when menthan-3,8-diol is mixed at a fixed ratio, the mixture becomes liquid. The mixture becomes liquid when one component is blended in 15% to 85% in any combination.
As described above, it has been discovered that if the cis-form and the trans-form of p-menthane-3,8-diol are mixed at a certain ratio, they become liquid at room temperature. It has become possible to build.

The next problem when constructing a sustained release system is to control the evaporation rate of the evaporative substance. This can be achieved by adjusting the rate at which the transpirable substance (p-menthane-3,8-diol) moves through the base material. In order to control the speed at which the evaporative substance moves through the base material, the Affi
nity controll (adjustment of affinity) is required.

In general, a solubility parameter (Solubility parameter) is known as a factor affecting the degree of affinity for a polymer. That is, if the solubility coefficient of the polymer (hereinafter abbreviated as SP value) and the SP value of a certain substance are close to each other, they have high affinity and good compatibility. Conversely, if the SP values of the polymer and its substance are far apart, they are poorly compatible and poorly compatible combinations.

Now, we recall that the repellent component of the present invention, p-menthane-
As a result of earnestly studying the affinity between 3,8-diol and various polymers, they have found a system that can continuously release the repellent component in small amounts within a range having an effect over a long period of time. is there. More specific explanation will be added.

To achieve a so-called sustained-release property, in which p-menthane-3,8-diol, which is a pest repellent component of the present invention, is released over a long period of time and in an effective range by using one kind of homopolymer. It is difficult. Because, when the affinity between the homopolymer and the repellent component is high, the compatibility is good, so the speed at which the repellent component moves in the polymer layer is extremely slow, and the repellent component from the surface layer into the air It is difficult to control volatilization appropriately, and effective repellency cannot be obtained. On the other hand, when the affinity between the homopolymer and the repellent component is low, the compatibility deteriorates, so that only a small amount of the repellent component can be blended, and it is difficult to uniformly disperse the repellent component in the base material. Therefore, the repellent component cannot form a continuous layer in the base material, and it is impossible to release the repellent component slowly.

Therefore, the pest repellent component of the present invention, p-menthane-
In order to achieve the sustained release of 3,8-diol, it is useful to use a polymer having two or more constituent molecules having different affinities with the repellent component in one molecule. For example, block copolymers, graft copolymers, random copolymers and the like are particularly useful. Also, a blend of a homopolymer is conceivable. That is, a blend of a polymer having a good affinity for the pest repellent component and a polymer having a bad affinity is also considered as one system. However, even when the homopolymers are blended in this way, the dissolution characteristics and the like are governed by the dissolution characteristics of each homopolymer, so that the repellent component is preferentially dissolved in the homopolymer having high affinity. For this reason, the speed at which the repellent component moves in the polymer layer becomes extremely slow, and even if the migration within the entire system is adjusted on the macroscopic surface at the grain boundary with the incompatible polymer, the migration from the surface layer is suppressed. It is difficult to appropriately control the volatilization of the repellent components into the air, and it is difficult to obtain effective repellency.

However, in the case of using a polymer having a portion of a constituent molecule having a different affinity for two or more kinds of repellent components in one molecule, such as a block copolymer, a graft copolymer, and a random copolymer, By appropriately adjusting the composition ratio of the type and length of the monomer unit, the volatilization rate of the repellent component can be adjusted. In such a copolymer, microphase separation within the molecule is achieved, and since each microdomain is highly dispersed, the repellent component is also microscopically dispersed in the copolymer molecule. ing. Such copolymers exhibit properties that cannot be achieved only by physically blending homopolymers. In other words, in a copolymer composed of a monomer unit having an SP value relatively close to the repellent component or an SP value far apart from a segment which is a continuous layer of monomers or a segment which is a continuous layer of monomers, it is necessary to control the compatibility with the repellent component well. Can be
Thereby, sustained release of the repellent component is achieved. The speed of the sustained release can be sufficiently adjusted by the composition ratio of the segments and the like. In addition, the polymer is a material as a carrier, and is a very convenient material.

Although the repellent component is volatile at normal temperature, it goes without saying that the higher the temperature, the greater the amount of volatilization. Therefore, if the molding temperature is high, the amount volatilized during molding is increased, which is not preferable. Therefore, it is necessary to select a material whose molding temperature is as low as possible.

As a result of intensive research to find a polymer that satisfies all of the above conditions, it has been found that when some thermoplastic elastomers are used, the repellent component is continuously released in small amounts over a long period of time. That is, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, acrylate-acrylonitrile copolymer,
Butadiene-acrylonitrile copolymer, ethylene-vinyl alcohol copolymer, partially saponified PVA, polyethylene glycol-polypropylene glycol copolymer, etc.
It has been found that the repellent component is effective for sustained release. Among them, they have found that an ethylene-vinyl acetate copolymer is optimal in consideration of the easiness of achieving a sustained release system and the goodness of a mold.

The SP value of p-menthane-3,8-diol is 13.8,
Among the ethylene-vinyl acetate copolymers, the SP value of the ethylene unit is 8.6, and the SP value of the vinyl acetate unit is 11.3. That is, p-menthane-3,8-diol and vinyl acetate units have relatively high affinity, while p-menthane-3,8-diol and ethylene units have relatively low affinity. By appropriately adjusting the composition ratio of the ethylene unit and the vinyl acetate unit, a system having a sustained release property of the repellent component could be established. That is,
If the constituent ratio of the vinyl acetate unit is increased, a system having a higher affinity with the repellent component can be constructed as a whole, so that the repellent component can be gradually released over a longer period of time. On the other hand, in the ethylene-vinyl acetate copolymer, when the constituent ratio of the vinyl acetate unit increases (40% by weight or more), the moldability deteriorates. Therefore, in order to achieve a longer-term sustained release, the composition ratio of the vinyl acetate unit is low, and the ethylene-vinyl acetate copolymer excellent in the mold is used as the base resin, and the composition ratio of the vinyl acetate unit is high. (50% by weight or more) A vinyl acetate-ethylene copolymer may be added to such an extent that the moldability does not deteriorate. For the construction of a sustained release system, it is most preferable to use an ethylene-vinyl acetate copolymer as a base resin. However, in some cases, a general-purpose resin such as polyvinyl chloride or polyethylene is used as a base resin, and vinyl acetate is added thereto. -By blending the ethylene copolymer, it is possible to construct a system having a sustained release property.

Now, the repellent component of the present invention, p-menthane-3,8-
As a method of blending a diol with a thermoplastic elastomer represented by an ethylene-vinyl acetate copolymer, a method in which a repellent component is added to a thermoplastic elastomer by stirring and dripping under heating, or kneading on a heating roll And the like. Further, it can be formed into an arbitrary shape such as a pellet shape, a sheet shape, a net shape, a rod shape and the like by a usual plastic molding machine. in this case,
The amount of p-menthane-3,8-diol which is a repellent component can be blended with the thermoplastic elastomer in an amount of usually 0.1 part to 30 parts.
Parts. However, ease of molding, efficacy duration,
Considering the cost and the like, it is desirable to mix about 1 to 15 parts.

In the present invention, p-menthane-3,8-diol may be used in combination with another repellent vegetable essential oil. Examples of such plant essential oils are peppermint oil, laurel oil,
Pine oil, eucalyptus butas oil, citronella oil, penny royal oil, cedar oil, henruuda oil, hinoki oil, lavender oil, peppermint oil, melissa oil, salvia oil, rosemary oil, cinnamon oil, clove oil and the like.

At the time of molding, a coloring agent, a filler, a plasticizer, and the like may be added as necessary.

The molded pellets can be spread directly on the base of the tree to protect the tree from insect pests, or filled in a container with an open part, and can be used in entrances, toilets, corners of rooms, or kennels. It is good to hang it inside. In addition, a sheet-like or net-like thing may be used by laying it in a dog house or wrapping it around a tree. Further, if a sheet-shaped material is attached to a dog or cat as a collar with a metal fitting attached to an appropriate size, it can be used as a collar capable of repelling pests such as mosquitoes, fleas and ticks. Furthermore, if a net-like thing is used together with a screen door, invasion of pests into a house can be more firmly prevented. It is good to wrap a rod-shaped thing around a tree or to hang it at the entrance of a kennel. Furthermore, it can be widely used as agricultural material.
In other words, if the present invention is applied to a support or a net for agricultural and horticultural use, it is possible to protect agricultural crops from pests. or,
In the field of sericulture, covering the perimeter of the silkworm with a pellet or a sheet can prevent invasion of pests into the silkworm and crawling of the silkworm.

 Hereinafter, the present invention will be described with reference to examples.

[Example-1] Ethylene-vinyl acetate copolymer (manufactured by Tosoh Corporation)
Product name: Ultrasen UE634] 100 parts of chlorinated polyethylene [Osaka Soda Co., Ltd., product name: Daisolak H-13]
5] 40 parts of aluminum hydroxide (particle size 3 μm), 40 parts of aluminum hydroxide (particle size 3 μm) and (+)-cis-p-menthane-3,8-diol and (−) as repellents
10 parts of a 1: 1 mixture of -trans-p-menthane-3,8-diol was added, mixed uniformly, and kneaded with a mixing roll to prepare a sheet having a thickness of 1 mm. The residual ratio of p-menthane-3,8-diol contained in the sheet-like pest repellent material over time was examined by gas chromatography.

On the other hand, as a comparative example, exactly the same as the formulation of the example,
Only the repellent is solid (+)-cis-p-menthane-3,
A sheet having a thickness of 1 mm was prepared in which 10 parts of 8-diol were used.
P-menthane-3, contained in this sheet-like pest repellent
The residual ratio of 8-diol over time was similarly examined by gas chromatography. The results were as follows.

As can be seen from the above results, the repellent p-menthane-3,8-diol was continuously released in small amounts over a period of 12 months in the example, whereas in the comparative example, Up to the sixth month, the repellent has been released continuously, but after that almost no repellent has been released. That is, according to the present invention, the cis-form and the trans-form of p-menthane-3,8-diol are mixed at a certain ratio as in the present invention, and liquid p-menthane-3,8-diol is repelled. It shows that it is easy to construct a sustained release system because it is used as an agent. On the other hand, the comparative example uses solid p-menthane-3,8-diol,
After about a month, it is considered that p-menthane-3,8-diol became difficult to maintain a continuous layer in the base material, and thereafter, the release of the repellent was hardly observed. . As described above, even if the same amount of repellent is blended, the repellent is liquid at room temperature,
It is possible to maintain a sustained release system for a longer period.

[Example-2] An ethylene-vinyl acetate copolymer containing 26% by weight of a vinyl acetate unit [trade name: Ultracene UE, manufactured by Tosoh Corporation]
634] A vinyl acetate-ethylene copolymer containing 60% by weight of a vinyl acetate unit in 100 parts [manufactured by Nippon Synthetic Chemical Industry Co., Ltd .:
20 parts of trade name Soabrene CI], and 10 parts of a 1: 1 mixture of (+)-cis-p-menthane-3,8-diol and (-)-trans-p-menthane-3,8-diol, The sheet was uniformly mixed and kneaded with a mixing roll to produce a sheet having a thickness of 1 mm. P-contained in this sheet-shaped pest repellent
The residual ratio of menthan-3,8-diol over time was examined by gas chromatography. The results were as follows.

As can be seen from the above results, the repellent p-menthane-3,8-diol was continuously released little by little, and a sustained release system was constructed.

〔The invention's effect〕

As described above, the present invention provides p-menthane-3,8
A mixture of a diol and a cis-isomer of a diol in a ratio of being liquid at room temperature, and adjusting the affinity of a thermoplastic elastomer as a base material thereof, to obtain p-menthane-3,
The rate of volatilization of the 8-diol was adjusted so that a small amount of the repellent could be continuously released over a long period of time in an effective range.

Also, p-menthane-3,8-diol is a natural product,
It is superior to other pest repellents in terms of safety.

In addition, the product of the present invention can be processed into an appropriate shape and used as a collar for dogs and cats, or if installed in a kennel, it can be used as a safe pest repellent, and your dog can be damaged by fleas and mites, It can be prevented from getting into a filaria etc.
Furthermore, if they are installed on trees in the garden, they can be slugs,
We can protect from armyworm. Further, if the present invention is applied to an agricultural or horticultural net or a support, agricultural crops can be protected from pests. Also, in the field of sericulture, if the area around the silkworm is covered with pellets or sheets,
It is possible to prevent pests from entering the silkworm and prevent the silkworm from crawling out.

Claims (2)

(57) [Claims] (1) a cis form and a trans form of p-menthane-3,8-diol are mixed at a ratio of 15 to 85%, respectively, and the resulting mixture is blended with a thermoplastic elastomer; Wood. 2. The sustained-release pest repellent material according to claim 1, wherein the thermoplastic elastomer is an ethylene-vinyl acetate copolymer.