AU2020220658A1 - Mosquito control aerosol and mosquito control method - Google Patents

Abstract

Provided is an aerosol for mosquitoes control use, which is improved in the operation stability of a fixed-amount injection valve after the repeated use of the aerosol, can exhibit an excellent control effect against mosquitoes for a long period, and is reduced in the influence on human bodies and pet animals.　An aerosol for mosquitoes control use, which is equipped with: a pressure-resistant container in which an aerosol stock solution comprising transfluthrin and/or metofluthrin that serves as an insect pest control component and a lower alcohol and/or a hydrocarbon-type solvent that serves as an organic solvent and a propellant are enclosed; a fixed-amount injection valve 100 which is equipped with a valve mechanism 10 including a stem 11, a stem rubber 12 and a spring 13 and a housing 20; and an injection button which has an injection port formed therein. In the aerosol, the volume ratio of the aerosol stock solution to the propellant is 6/94 to 50/50, the material for the stem rubber 12 is an acrylonitrile-butadiene rubber, and the spring 13 is a reinforced spring.

Description

DESCRIPTION MOSQUITO CONTROL AEROSOL AND MOSQUITO CONTROL METHOD TECHNICAL FIELD

[0001]

The present invention relates to a mosquito control

aerosol comprising: a pressure-resistant container that

contains an aerosol-forming material including an insect pest

control component and an organic solvent, and a propellant; a

fixed-amount spray valve attached to an open part of the

pressure-resistant container; and a spray button having a

spray outlet connected to the fixed-amount spray valve. The

present invention also relates to a mosquito control method

using the mosquito control aerosol.

BACKGROUND ART

[0002]

Among the techniques of getting rid of flying insect

pests are: vaporizing and diffusing a chemical including an

insecticidal component from a carrier impregnated with the

chemical into a treatment space; directly spraying a chemical

to a flying insect pest; and previously spraying a chemical to

a place where flying insect pests are highly likely to come,

for example. In this regard, insecticide aerosols containing

an insecticidal component have been developed as a product for getting rid of flying insect pests entering indoors.

Insecticide aerosols allow easy spraying of an insecticidal

component into a treatment space, and therefore, are widely

used as a convenient product.

[00031

In some conventional insecticide aerosols, the decrease

in the proportion of the chemical remaining in the air in

a room is reduced (see, for example, Patent Literature

1). According to Patent Literature 1, after being released,

the chemical is allowed to remain in the air so that the

decrease in the concentration thereof in the air is

reduced, whereby the effect of getting rid of mosquitoes

can be sustained enough for hiding mosquitoes.

[0004]

There are also some insecticide aerosols in

which particles produced by spraying the chemical into a room

have a particle size greater than that of Patent Literature

1 (see, for example, Patent Literature 2). Patent

Literature 2 discloses an insecticide aerosol that is

based on technical aspects similar to those of Patent

Literature 1, and that has a high effect of killing

mosquitoes by allowing the chemical to remain in the air in a

room for as long as possible.

[00051

Meanwhile, concerning insecticide aerosols, there are

some techniques of getting rid of flying insect pests in a

room of a house by causing the chemical to adhere to the surface of objects or fixtures and fittings in the room

(see, for example, Patent Literature 3). According to

Patent Literature 3, a particular chemical compound caused to

adhere to objects, etc., in a room evaporates and diffuses

into the room. Therefore, flying insect pests in a

house can be efficiently got rid of by a simple means

without the necessity of repeated spraying or continual

operation of electrical equipment, etc.

[00061

Bearing in mind the widespread use of fixed-amount spray

type insecticide aerosols, the present inventors have

developed an insect pest control method using a fixed-amount

spray type aerosol, wherein: at least one insect pest control

component selected from the group consisting of metofluthrin,

profluthrin, and transfluthrin is used; a lower alcohol having

two or three carbon atoms is used as a solvent; a spray force,

the particle size distribution of sprayed particles, and the

adhesion efficiency of sprayed particles to a floor surface

and a wall surface in a room, are specified; and both flying

insect pests and crawling insect pests can be controlled over

5-12 hours in a treatment space (see Patent Literature 4).

CITATION LIST PATENT LITERATURE

[0007]

Patent Literature 1: Japanese Unexamined Patent

Application Publication No. 2001-17055

Patent Literature 2: Japanese Unexamined Patent

Application Publication No. 2013-99336

Patent Literature 3: Japanese Unexamined Patent

Application Publication No. 2001-328913

Patent Literature 4: Japanese Patent No. 5517496

SUMMARY OF INVENTION TECHNICAL PROBLEM

[00081

According to the insecticide aerosol of Patent

Literature 1, an attempt has been made to increase the

duration for which the chemical remains in the air by

adjusting the particle size of the chemical diffused in a room

so that the effect of the chemical is sustained over a longer

period of time. However, the proportion of chemical particles

remaining in the air 12 hours or more after the start of the

treatment is 0.5% or more. The duration of the insecticide

aerosol of Patent Literature 1, which is intended to maintain

the proportion of the chemical remaining in the air, is

limited. Also, in Patent Literature 2, the proportion of

chemical particles remaining in the air is similar to that of

Patent Literature 1. The insecticide aerosol of Patent

Literature 2 cannot be expected to provide long-lasting

effect.

[00091

Of mosquitoes to be controlled (it is herein assumed

that the mosquitoes include not only mosquitoes of the

Culicidae, such as Culex pipiens and Aedes albopictus, but

also Chironomidae, Psychodidae, etc., of the suborder

Nematocera), particularly Culex pipiens and Aedes albopictus

not only suck blood but also transmit infectious disease. It

is necessary to protect individuals against these mosquitoes.

There is an increasing demand for establishment of a more

effective technique of getting rid of these mosquitoes.

Mosquitoes are flying insect pests that enter indoors

night and day. Therefore, ideally, the effect of an

should be sustained all day, i.e., for a 24-hour periodecticide

[0010]

As described above, however, the effects of the

insecticide aerosols of Patent Literatures 1 and 2 are

sustained for as short as about 12 hours. Also, in Patent

Literatures 1 and 2, the particle size of the chemical is

adjusted so as to deliberately cause the chemical to remain in

the air. However, the presence of chemical particles remaining

in the air means that a human or pet in the treatment space

may spend a long time in an environment in which they inhale

the chemical. Therefore, the insecticide aerosols of Patent

Literatures 1 and 2 are also not preferable in terms of

influence on humans and pets.

[0011]

The technique of getting rid of flying insect pests according to Patent Literature 3 is unclear as to whether or not the effect can be maintained stable over a long period of time. Chemical particles sprayed into the air may behave in any of the following ways: (A) remaining suspended in the air;

(B) adhering to a floor or a wall; (C) after (B), vaporizing

and/or diffusing again; or (D) decomposing and disappearing

due to light, etc. In this regard, the technique of Patent

Literature 3 corresponds to (C) . However, when the chemical

adhering to objects, etc., in a room vaporizes and/or diffuses

into the air again, the vaporization and/or diffusion are

easily affected by temperature, airflow, etc. Therefore, the

technique of Patent Literature 3 does not always provide a

stable effect of getting rid of flying insect pests.

[0012]

In the insect pest control method of Patent Literature

4, the lower alcohol having two or three carbon atoms used as

a solvent, which more quickly dries than other solvents such

as higher fatty acid esters, and therefore, vaporizes quickly

after being sprayed, so that the concentration of the insect

pest control component in sprayed particles is increased,

resulting in an improved control effect, and therefore, is

highly useful for fixed-amount spray type aerosols. However,

the insect pest control effect of the insecticide aerosol used

in the insect pest control method of the Patent Literature 4

is also sustained for as short as about 12 hours. The present

inventors' various studies on fixed-amount spray type aerosols in which a lower alcohol having two or three carbon atoms is used as a solvent, have demonstrated that repeated use of the fixed-amount spray type aerosol may affect the operational stability of the fixed-amount spray valve. There is room for improvement in the insecticide aerosol of Patent

Literature 4. [0013]

With the above problems in mind, the present invention

has been made. It is an object of the present invention

to provide: a mosquito control aerosol which can exhibit a

good

control effect on flying insect pests, particularly

mosquitoes, over a long period of time with improved

operational stability of a fixed-amount spray valve after

repeated use thereof, and that has reduced influence on humans

and pets; and a mosquito control method using the mosquito

control aerosol.

SOLUTION TO PROBLEM

[0014]

To achieve the above object, a mosquito control aerosol

according to the present invention comprises:

a pressure-resistant container containing an aerosol

forming material including transfluthrin and/or metofluthrin,

which are an insect pest control component, and a lower

alcohol and/or a hydrocarbon solvent, which are an organic

solvent, and a propellant;

a fixed-amount spray valve having a valve mechanism including a stem, a stem rubber, and a spring, and a housing for the valve mechanism, wherein the fixed-amount spray valve is attached to an open part of the pressure-resistant container; and a spray button having a spray outlet connected to the fixed-amount spray valve, wherein the volume ratio (a/b) of the aerosol-forming material

(a) to the propellant (b) is 6/94 to 50/50,

a material for the stem rubber is acrylonitrile

butadiene rubber,

the spring is a reinforced spring,

the volume of the aerosol-forming material sprayed when

the spray button is pressed down once is 0.1 to 1.0 mL, and

sprayed particles sprayed from the spray outlet have a

particle size of 10 to 80 pm, where the particle size is a d90

particle size in a volume cumulative distribution of the

sprayed particles as measured at a distance of 15 cm from the

spray outlet at 25°C.

[0015]

As described in the above section "TECHNICAL PROBLEM,"

conventional insecticide aerosols have been developed such

that chemical particles are deliberately caused to diffuse

into a treatment space, and remain in the air for as long as

possible. However, in the case where the chemical particles suspended in the treatment space remain over a long period of time, a human or pet, when entering the treatment space, is likely to inhale the chemical particles, leading to a risk of health problems.

[0016]

Incidentally, the present inventors' study has found

that, for mosquitoes typified by Culicidae (hereinafter simply

referred to as "mosquitoes"), the time that the insect is

sitting on a wall surface, etc., is longer than the time that

the insect is flying. In other words, most of mosquitoes

that have entered indoors are sitting on a wall surface,

etc., to

wait for a chance to suck blood from a human. Therefore,

although the conventional technique of causing chemical

particles to be suspended in a treatment space over a longer

period of time can exhibit the effect of controlling

mosquitoes that are flying, to some degree, the effect of the

chemical cannot sufficiently affect mosquitoes sitting on a

wall surface, etc. As a result, mosquitoes cannot be

completely controlled. The present inventors have envisaged,

based on the above study result, that, by enhancing the effect

of controlling mosquitoes sitting on a wall surface, etc., the

control of all mosquitoes entering indoors can be improved

while reducing inhalation of a chemical by a human or pet.

[0017]

Therefore, according to the mosquito control aerosol of

the present invention, when the aerosol-forming material is sprayed into a treatment space, the sprayed particles move and adhere to an exposed portion in the treatment space

(e.g., a floor surface or a wall surface, a surface of an

object, such

as furniture, etc., in the treatment space). Therefore,

mosquitoes sitting on the exposed portion and mosquitoes

flying in the treatment space can both be effectively knocked

down or killed, whereby the effect of controlling all

mosquitoes can be improved. The sprayed particles of aerosols

have been extensively studied by the present inventors. As a

result, the present inventors have found that if an aerosol

forming material containing transfluthrin and/or metofluthrin

as an insect pest control component, and a lower alcohol

and/or a hydrocarbon solvent as an organic solvent, is

employed, particles suitable for control of mosquitoes are

advantageously formed. In this case, the effect of the insect

pest control component contained in the sprayed particles can

be reliably and efficiently exhibited. Also, the aerosol

forming material can be easily formulated.

[0018]

In addition, if the volume ratio (a/b) of the aerosol

forming material (a) to the propellant (b) is adjusted to 6/94

to 50/50, and the volume of the aerosol-forming material

sprayed when the spray button is pressed down once is 0.1 to

1.0 mL, the sprayed particles quickly move and adhere to an

exposed portion in a treatment space. As a result, the insect

pest control component can reliably knock down or kill mosquitoes sitting on the exposed portion.

[0019]

Furthermore, the sprayed particles are formed to have a

particle size within the range of 10 to 80 pm, where the

particle size is a d90 particle size in a volume cumulative

distribution of the sprayed particles as measured at a

distance of 15 cm from the spray outlet at 250C. Within such a

range, the insect pest control component can reliably knock

down or kill mosquitoes sitting on the exposed portion.

[0020]

The fixed-amount spray valve of the mosquito control

aerosol of the present invention has a valve mechanism

including a stem, a stem rubber, and a spring, and a housing

for the valve mechanism. If a material for the stem rubber is

acrylonitrile butadiene rubber and the spring is a reinforced

spring, the operational stability of the fixed-amount spray

valve is improved, and an un-biased state to which the spray

button returns after being pressed down is good even after

repeated use of the mosquito control aerosol.

[0021]

In the mosquito control aerosol of the present

invention,

the reinforced spring preferably has a spring constant

of 3.3 N/mm or more.

[0022]

With the mosquito control aerosol thus configured, the

use of a spring having a spring constant of 3.3 N/mm or more

further improves the operational stability of the fixed-amount

spray valve, and allows the spray button of the mosquito

control aerosol to reliably return to the original position

(un-biased state) even after the spray button is pressed down

many times. Therefore, the mosquito control aerosol can

maintain quality and performance suitable for aerosols over a

long period of time.

[0023]

In the mosquito control aerosol of the present

invention,

the insect pest control component is preferably

transfluthrin.

[0024]

In the case where the insect pest control component is

transfluthrin, the mosquito control aerosol thus configured

can more effectively control mosquitoes.

[0025]

In the mosquito control aerosol of the present

invention,

preferably, when the aerosol-forming material is sprayed

into a treatment space once, the proportion of the insect pest

control component remaining in the air after two hours have

passed is 0.05 to 5%, and a period of time during which an

effect of the insect pest control component is sustained is 18 hours or more in a space of 33.3 m 3 or less.

[0026]

The mosquito control aerosol thus configured is adjusted

such that when the aerosol-forming material is sprayed into a

treatment space once, the proportion of the insect pest

control component remaining in the air (in the treatment

space) after two hours have passed is 0.05 to 5%, and a period

of time during which the effect of the insect pest control

component is sustained is 18 hours or more in a space of 33.3

m3 or less. The sprayed particles sprayed into the treatment

space quickly move and adhere to an exposed portion in the

treatment space. Meanwhile, the amount of the sprayed

particles drifting in the treatment space decreases

proportionately with the amount of the sprayed particles

adhering to the exposed portion. In other words, according to

the mosquito control aerosol of the present invention, the

aerosol-forming material is not diffused throughout the

treatment space like the conventional products, and therefore,

the influence on a human or pet can be significantly reduced

compared to the conventional products. In addition, the insect

pest control component of the sprayed particles drifting in

the treatment space can exhibit the effect of knocking down or

killing mosquitoes flying in the treatment space. In addition,

according to the mosquito control aerosol of the present

invention, when the aerosol-forming material is sprayed into a

treatment space only once, the insect pest control effect can be sustained over 18 hours or more in a space of 33.3 m3 or less. Therefore, the space can repel insect pests and can therefore be maintained comfortable substantially all day.

[0027]

In the mosquito control aerosol of the present

invention,

the sprayed particles sprayed from the spray outlet

preferably have a particle size of 25 to 70 pm, where the

particle size is a d90 particle size in a volume cumulative

distribution of the sprayed particles as measured at a

distance of 15 cm from the spray outlet at 250C.

[0028]

With the mosquito control aerosol thus configured, the

sprayed particles are adjusted to the above optimum range,

and therefore, the sprayed particles more quickly move and

adhere to an exposed portion in the treatment space.

Therefore, mosquitoes sitting on the exposed portion can be

more reliably knocked down or killed.

[0029]

In the mosquito control aerosol of the present

invention,

the volume of the aerosol-forming material sprayed when

the spray button is pressed down once is preferably 0.1 to 0.2

mL.

[0030]

With the mosquito control aerosol thus configured, the

sprayed volume is adjusted to the above optimum range, and

therefore, the sprayed particles are present in a more

suitable state, whereby the effect of the insect pest control

component can be exhibited at a maximum level.

[0031]

In the mosquito control aerosol of the present

invention,

the amount of the insect pest control component sprayed

when the spray button is pressed down once is preferably 5.0

to 30 mg per treatment space of 18.8 to 33.3 M 3

.

[0032]

With the mosquito control aerosol thus configured, the

amount of the insect pest control component sprayed when the

spray button is pressed down once is adjusted to the above

optimum range, and therefore, the sprayed particles quickly

move and adhere to an exposed portion in the treatment space.

As a result, the insect pest control component can reliably

knock down or kill mosquitoes sitting on the exposed portion.

[0033]

In the mosquito control aerosol of the present

invention,

the organic solvent is preferably a lower alcohol having

two or three carbon atoms.

[0034]

With the mosquito control aerosol thus configured, in the case where the organic solvent is a lower alcohol having two or three carbon atoms, the effect of the insect pest control component can be more efficiently exhibited.

[00351

In the mosquito control aerosol of the present

invention,

the aerosol-forming material preferably contains, as an

anti-susceptibility reduction aid for transfluthrin, a higher

fatty acid ester having a total of 13 to 20 carbon atoms

and/or a glycol having 3 to 6 carbon atoms.

[00361

With the mosquito control aerosol thus configured, the

higher fatty acid ester having a total of 13 to 20 carbon

atoms and/or the glycol having 3 to 6 carbon atoms, when used

in combination with transfluthrin, act as an anti

susceptibility reduction aid. Therefore, the mosquito control

aerosol can exhibit a high control effect on mosquitoes

having reduced susceptibility to transfluthrin.

[0037]

To achieve the above object, a mosquito control method

according to the present invention comprises:

using the mosquito control aerosol as described in any

one of the above aspects to spray the aerosol-forming

material into a treatment space in order to knock down

or kill mosquitoes.

[00381

The mosquito control method thus configured is performed

using the mosquito control aerosol of the present invention,

and therefore, can exhibit a good mosquito control effect as

described above.

BRIEF DESCRIPTION OF DRAWINGS

[00391

[FIG. 1] FIG. 1 is a cross-sectional view of a fixed

amount spray valve included in a mosquito control aerosol

according to the present invention.

[FIG. 2] FIG. 2 is a model diagram showing behavior of

sprayed particles when an aerosol-forming material is sprayed

into a treatment space.

DESCRIPTION OF EMBODIMENTS

[0040]

A mosquito control aerosol according to the present

invention comprises: a pressure-resistant container that

contains an aerosol-forming material including transfluthrin

and/or metofluthrin as an insect pest control component, and a

lower alcohol and/or a hydrocarbon solvent as an organic

solvent, and a propellant; a fixed-amount spray valve that is

attached to an open part of the pressure-resistant container;

and a spray button having a spray outlet connected to the

fixed-amount spray valve. The mosquito control aerosol of the

present invention will be described below. Note that the present invention is not intended to be limited to configurations in embodiments and drawings described below.

[0041]

<Aerosol-Forming Material>

[Insect Pest Control Component]

Transfluthrin and/or metofluthrin, which are a

pyrethroid compound, are used as the insect pest control

component, which is one of the main components of the aerosol

forming material. Transfluthrin and metofluthrin include

optical and geometric isomers based on asymmetric carbons,

which are included in the present invention. A preferable

insect pest control component is transfluthrin. Transfluthrin

is advantageously effective to flying insect pests having

reduced susceptibility to a pyrethroid compound compared to

metofluthrin and profluthrin. Therefore, in the case where

transfluthrin is used as the insect pest control component,

the reduction of the control effect of the mosquito control

aerosol of the present invention on pyrethroid-resistant

strains of flying insect pests is relatively small.

[0042]

The amount of the insect pest control component included

in the aerosol-forming material is preferably 1.0 to 60% by

weight, taking it into consideration that the insect pest

control component is dissolved in the lower alcohol and/or

hydrocarbon solvent used as an organic solvent before being

sprayed into a treatment space. Within such a range, the insect pest control component is easily dissolved in the lower alcohol and/or hydrocarbon solvent (organic solvent), and when the aerosol-forming material is sprayed, sprayed particles are easily formed in an optimum state, whereby the effect of the insect pest control component can be exhibited.

If the amount of the insect pest control component included

in the aerosol-forming material is less than 1.0% by

weight, the effect of the insect pest control component

cannot be effectively exhibited, resulting in an

insufficient effect of controlling mosquitoes. Meanwhile,

if the amount of the insect pest control component

included in the aerosol-forming material exceeds 60% by

weight, the concentration of the insect pest control

component is high, and therefore, it is difficult to

appropriately formulate the aerosol-forming material.

[0043]

As described above, the insect pest control component

contained in the mosquito control aerosol of the present

invention is preferably transfluthrin and/or metofluthrin. In

addition to these components, the mosquito control aerosol of

the present invention may contain other pyrethroid compounds

such as profluthrin, meperfluthrin, empenthrin, dimefluthrin,

momfluorothrin, heptafluthrin, phthalthrin, resmethrin,

cyfluthrin, phenothrin, permethrin, cyphenothrin,

cypermethrin, allethrin, prallethrin, furamethrin,

imiprothrin, and etofenprox, silicon-based compounds such as

silafluofen, organic phosphorus-based compounds such as dichlorvos and fenitrothion, carbamate compounds such as propoxur, etc.

[0044]

The insect pest control component is preferably adjusted

such that when the aerosol-forming material is sprayed into a

treatment space once, the proportion of the insect pest

control component remaining in the air (in the treatment

space) after two hours have passed is 0.05 to 5%. The

proportion remaining in the air is represented by the

proportion of the number of particles present in a treatment

space after a predetermined period of time has passed (Q) to

the number of particles present in the treatment space

immediately after spraying (P), i.e., Q/P x 100 (%). This can

be easily calculated based on the theoretical concentration

(by weight) of the insect pest control component in the air,

and the concentration (by weight) of the insect pest control

component in the air after a predetermined period of time has

passed, as described in examples below. The amount of the

aerosol-forming material sprayed is preferably adjusted such

that the amount of transfluthrin sprayed is 5.0 to 30 mg per

treatment space of 18.8 to 33.3 m3 (a room of 4.5 to 8 Jyos

(Jyo is a Japanese unit of area: 1 Jyo is equal to about 1.67

M2 ), i.e., having an area of 7.5 to 13.3 m 2 and a height of 2.2

to 3.0 m). Within such a range, sprayed particles are formed

in an optimum state from the aerosol-forming material, and can

exhibit the insect pest control effect. Also, although the proportion remaining in the air is relatively low as described above, mosquitoes can be effectively knocked down or killed. Furthermore, even when a human or pet in the treatment space inhales the insect pest control component, the human or pet is not likely to be affected by the insect pest control component, and therefore, the mosquito control aerosol of the present invention can be safely used.

[0045]

[Organic Solvent]

In addition to the above insect pest control component,

the aerosol-forming material contains an organic solvent as a

main component. As the organic solvent, one is employed that

allows the insect pest control component to be dissolved

therein to formulate the aerosol-forming material, and allows

the formulated aerosol-forming material to form optimum

sprayed particles when the formulated aerosol-forming material

is sprayed into a treatment space. In the mosquito control

aerosol of the present invention, a lower alcohol and/or a

hydrocarbon solvent are used as the organic solvent. The lower

alcohol is preferably one that has two or three carbon atoms.

Examples of the lower alcohol having two or three carbon atoms

include ethanol, normal propanol, and isopropanol (IPA).

Examples of the hydrocarbon solvent include normal paraffin

and isoparaffin. Of them, lower alcohols having two or three

carbon atoms are preferable, particularly preferably ethanol.

Lower alcohols having two or three carbon atoms quickly dry, and vaporize quickly after being sprayed, so that the concentration of the insect pest control component in sprayed particles is increased, resulting in particles suitable for controlling of mosquitoes, and therefore, the effect of the insect pest control component contained in sprayed particles can be reliably and efficiently exhibited. In addition, the aerosol-forming material can be easily formulated. In addition, as an organic solvent, glycol ethers and the like can be added.

[0046]

[Anti-Susceptibility Reduction Aid]

To the aerosol-forming material, a higher fatty acid

ester having a total of 13 to 20 carbon atoms and/or a glycol

having 3 to 6 carbon atoms are preferably added as an anti

susceptibility reduction aid for a pyrethroid compound.

Examples of the higher fatty acid ester having a total of 13

to 20 carbon atoms include isopropyl myristate (IPM), methyl

myristate, hexyl laurate, and isopropyl laurate. Examples of

the glycol having 3 to 6 carbon atoms include 1,3-butylene

glycol, 1,4-butylene glycol, dipropylene glycol, 1,2

hexanediol, and 1,6-hexanediol. The present inventors have

found that the higher fatty acid ester having a total of 13 to

20 carbon atoms and the glycol having 3 to 6 carbon atoms are

specifically effective to insect pests, particularly

mosquitoes, that have reduced susceptibility to a pyrethroid

compound, and the action thereof is useful for an anti susceptibility reduction aid. If 2.0 to 20% by weight of these are added to the aerosol-forming material, the usefulness thereof can particularly be improved. Although a compound that enhances the original insecticidal pyrethroid effect on susceptible insect pests is often called an "efficacy enhancer, " a compound that reduces a decrease in a control effect on insect pests having reduced susceptibility is herein defined as an "anti-susceptibility reduction aid," and is distinguished from conventional "efficacy enhancers." The action mechanisms of the two types of compounds have not been definitely clarified. An "efficacy enhancer" does not necessarily correspond to an "anti-susceptibility reduction aid." If the added amount of the anti-susceptibility reduction aid is less than 2.0% by weight, the effect of reducing a decrease in the insect pest control effect is poor. Meanwhile, if the added amount of the anti-susceptibility reduction aid exceeds 20% by weight, the insect pest control effect is not further improved, and properties of the aerosol-forming material may be affected.

[0047]

[Other Components]

In the mosquito control aerosol of the present

invention, a nonionic surfactant may be added as a

solubilizing agent to the aerosol-forming material in addition

to the above components. Examples of the nonionic surfactant

include ethers such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, and polyoxyethylene alkyl amino ethers, fatty acid esters such as polyethylene glycol fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and polyoxyethylene glycerin fatty acid esters, polyoxyethylene styrenated phenol, and polyalkanolamides of fatty acids. Of these, the ethers can be preferably used.

[0048]

The mosquito control aerosol of the present invention

may optionally contain acaricides, fungicides, antimicrobial

agents, and bactericides against molds, fungi, etc.,

fragrances, deodorants, stabilizers, antistatic agents,

defoamers, excipients, synergists, etc. Examples of the

acaricide include 5-chloro-2-trifluoromethane sulfonamide

methyl benzoate, phenyl salicylate, and 3-iodo-2-propynylbutyl

carbamate. Examples of the fungicide, antimicrobial agent, and

bactericide include hinokitiol, 2-mercaptobenzothiazole, 2-(4

thiazolyl)benzimidazole, 5-chloro-2-methyl-4-isothiazoline-3

one, triforine, 3-methyl-4-isopropylphenol, and ortho

phenylphenol. Examples of the fragrance include fragrant

components such as orange oil, lemon oil, lavender oil,

peppermint oil, eucalyptus oil, citronella oil, lime oil, yuzu

oil, jasmine oil, cypress oil, green tea essential oil,

limonene, ax-pinene, linalool, geraniol, phenylethyl alcohol,

amylcinnamic aldehyde, cuminaldehyde, and benzyl acetate, and perfume components mixed with a leaf alcohol or leaf aldehyde called "green leaf volatile." Examples the synergist of include piperonyl butoxide and octyl bicycloheptene dicarboximide.

[0049]

<Propellant>

Examples of the propellant used in the mosquito control

aerosol of the present invention include liquefied gases such

as liquefied petroleum gas (LPG), dimethyl ether (DME), and

hydrofluoroolefins, and compressed gas such as nitrogen gas,

carbonic acid gas, nitrous oxide, and compressed air. These

propellants may be used alone or in combination. It is easy to

use a propellant containing LPG as a main component.

[0050]

In the mosquito control aerosol of the present

invention, the volume ratio (a/b) of the aerosol-forming

material (a) to the propellant (b) is adjusted to 6/94 to

50/50. Within such a range, optimum sprayed particles can be

formed from the spray outlet connected to the fixed-amount

spray valve attached to the pressure-resistant container. The

sprayed particles which have once been sprayed can quickly

move and adhere to an exposed portion in a treatment space.

Meanwhile, a portion of the sprayed particles which have not

adhered to an exposed portion drift in the treatment space,

but the amount thereof is not as large as they can affect a

human or pet. Thus, the sprayed particles are present in a treatment space in an optimum state, and can exhibit the insect pest control effect at a maximum level. If the proportion of the propellant (b) is increased so that the volume ratio (a/b) deceases from 6/94, i.e., the amount of the propellant contained in the pressure-resistant container is increased, sprayed particles formed from the sprayed aerosol-forming material have an unnecessarily small size, so that the amount of the sprayed particles adhering to an exposed portion in a treatment space is reduced. As a result, mosquitoes sitting on the exposed portion may not be reliably controlled. Meanwhile, if the proportion of the propellant (b) is decreased so that the volume ratio (a/b) increases from 50/50, i.e., the amount of the propellant contained in the pressure-resistant container is decreased, it is difficult for the sprayed aerosol-forming material to form sprayed particles having particle sizes falling within the above optimum range, and therefore, the sprayed particles quickly settle after being sprayed.

Therefore, the sprayed particles are quantitatively

insufficient, and therefore, it is difficult to quickly knock

down or kill mosquitoes.

[0051]

<Mosquito Control Aerosol>

The mosquito control aerosol of the present invention

mainly comprises a pressure-resistant container (aerosol

container), a fixed-amount spray valve, and a spray button. As

described above, an insect pest control component, an organic solvent, a propellant, and other optional components to be added, are selected, and placed in the pressure-resistant container with the fixed-amount spray valve attached to an open part thereof, and the spray button having a spray outlet is connected to the fixed-amount spray valve, to produce an aerosol product. This aerosol product is the mosquito control aerosol of the present invention, which is used to spray the aerosol-forming material in the form of sprayed particles into a treatment space. The aerosol-forming material mainly includes the insect pest control component and the organic solvent. Although, strictly speaking, the aerosol-forming material is separate from the propellant, the aerosol-forming material is released together with the propellant from the pressure-resistant container, and therefore, in the description that follows, in some cases, the components contained in the aerosol including the aerosol-forming material and the propellant may be collectively referred to as an "aerosol-forming material."

[0052]

<Fixed-Amount Spray Valve>

FIG. 1 is a cross-sectional view of a fixed-amount spray

valve 100 included in the mosquito control aerosol of the

present invention. The fixed-amount spray valve 100 is firmly

fixed to an open part of the pressure-resistant container, and

is connected to a spray button. The spray button is a movement

unit for spraying the aerosol-forming material. The spray button has a spray outlet through which the aerosol-forming material is sprayed from the aerosol container into the outside (treatment space). The fixed-amount spray valve 100 has a valve mechanism 10 including a stem 11, a stem rubber 12, and a spring 13, and a housing 20 for the valve mechanism 10. A reinforced spring is used as the spring 13. Acrylonitrile butadiene rubber is used as a material for the stem rubber 12. The lower alcohol having two or three carbon atoms used as the organic solvent in the mosquito control aerosol of the present invention more quickly dries than other solvents such as higher fatty acid esters, and therefore, vaporizes quickly after being sprayed, so that the concentration of the insect pest control component in sprayed particles is increased. In this regard, the lower alcohol having two or three carbon atoms is highly useful for fixed amount spray type aerosols. However, the lower alcohol having two or three carbon atoms may have an influence on the operational stability of the fixed-amount spray valve after repeated use of the aerosol. In order to improve the operational stability of the fixed-amount spray valve after repeated use, a material for the stem rubber may be modified.

However, the suitability of the stem rubber for the solvent

depends on a number of factors. Taking this into

consideration, attempts have been made to (1) modify a

material for the stem rubber, and in addition, (2) change the

structure specifications. As a result, it has been found that the operational stability of the fixed-amount spray valve can be improved by using acrylonitrile butadiene rubber as a material for the stem rubber and a reinforced spring as the spring. The present invention has thus been completed. The reinforced spring preferably has a spring constant of 3.3 N/mm or more. Here, the spring constant can be calculated by: spring constant (N/mm) = (shear modulus x wire diameter to the power of four)/(8 x effective number of turns x central diameter to the power of three) (1)

An example of a spring having a spring constant of 3.3

N/mm or more is a reinforced spring manufactured by Mitani

Valve Co., Ltd. (model No.: SP-C321). According to a catalog

published by Mitani Valve Co., Ltd., a conventional spring

(model No.: SP-C314) is made of stainless (SUS304) and has a

wire diameter of 00.55 mm and a number of turns of 9 and 3/4,

while the reinforced spring has a wire diameter that is 00.6 mm

greater than 00.55 mm, and therefore, has a higher spring

pressure.

[00531

In the fixed-amount spray valve 100, a predetermined

amount of the aerosol-forming material is introduced from the

pressure-resistant container into a fixed-amount chamber 21.

When the spray button of the mosquito control aerosol is

pressed down once, the fixed-amount spray valve 100 is

actuated by the pressure of the propellant, and the aerosol forming material in the fixed-amount chamber 21 is lifted to the spray outlet, and then sprayed into a treatment space. The volume of the sprayed aerosol-forming material at this time is adjusted to 0.1 to 1.0 mL, more preferably 0.1 to 0.2 mL. In the mosquito control aerosol of the present invention, the stem rubber of acrylonitrile butadiene rubber and the reinforced spring cooperate with each other, resulting in an improvement in the operational stability of the fixed-amount spray valve, which further stabilizes the volume of the sprayed aerosol-forming material. If the volume of the sprayed aerosol-forming material is within the above range, sprayed particles which are formed from the sprayed aerosol-forming material can optimally exhibit the control effect in the treatment space. If the spray volume is less than 0.1 mL, then the spray volume is excessively small, and therefore, only a small amount of sprayed particles move to an exposed portion in the treatment space, and there is not enough of the sprayed particles adhering to the exposed portion, so that it is difficult to knock down or kill mosquitoes sitting on the exposed portion. Also, because the total amount of the sprayed particles is small, only a small amount of sprayed particles drift in the treatment space, so that it is difficult to knock down or kill mosquitoes flying in the treatment space.

Meanwhile, if the spray volume exceeds 1.0 mL, an

unnecessarily large amount of the aerosol-forming material is

released in the form of sprayed particles into the treatment space, so that there may be a risk of influence on a human or pet. Also, the amount of the aerosol-forming material that is consumed is excessively large, resulting in economic disadvantage.

[0054]

The amount of the insect pest control component sprayed

is adjusted to 5.0 to 30 mg per treatment space of 18.8 to

33.3 m3 as described above, preferably 6.1 to 25 mg.

Incidentally, a space of 18.8 to 33.3 m3 corresponds to a room

of 4.5 to 8 Jyos. Within such a range, the insect pest control

effect can be appropriately exhibited to reliably knock down

or kill mosquitoes in the treatment space. If the amount of

the insect pest control component sprayed is less than 5.0 mg,

the amount of the sprayed particles adhering to an exposed

portion in the treatment space is small, and therefore,

the insect pest control component effect is not

satisfactorily exhibited, so that it is difficult to knock

down or kill mosquitoes sitting on the exposed portion.

Meanwhile, if the amount of the insect pest control component

sprayed exceeds 30 mg, an unnecessarily large amount of the

insect pest control component is released into the treatment

space, so that there may be a risk of influence on a human or

pet. Also, the amount of the insect pest control component

that is consumed is excessively large, resulting in economic

disadvantage.

[0055]

The mosquito control aerosol of the present invention is adjusted to have a spray force of 0.3 to 20.0 g-f, preferably

0.3 to 10.0 g-f, as measured at a distance of 20 cm from the

spray outlet at 250C. Within such a range, by spraying the

aerosol-forming material once, sprayed particles sprayed from

the spray outlet are allowed to quickly reach an exposed

space, whereby the effect of the insect portion in a treatment

pest control component can be exhibited. Such a spray force

may be appropriately adjusted based on the composition of the

aerosol-forming material, the inner pressure of the aerosol

container, the shape of the spray outlet, etc. Note that in

this embodiment, the spray force of the mosquito control

aerosol was measured using a digital force gauge (FGC-0.5,

manufactured by Nidec-Shimpo Corporation). Furthermore, the

spray outlet preferably has an inner diameter of 0.2 to 1.0

mm. Within such a range, the particle size and the spray force

can be appropriately adjusted such that optimum sprayed

particles can be formed from the aerosol-forming material

sprayed into a treatment space, and therefore, the insect pest

control effect can be exhibited, whereby mosquitoes in the

treatment space can be reliably knocked down or killed.

[00561

FIG. 2 is a model diagram showing behavior of sprayed

particles of the aerosol-forming material which occurs when

the aerosol-forming material is sprayed into a treatment

space. FIG. 2 (a) is a model diagram showing a case where a conventional mosquito control aerosol is sprayed into a treatment space. FIG. 2 (b) is a model diagram showing a case where the mosquito control aerosol of the present invention is sprayed into a treatment space. As shown in FIG. 2(a), in the case of the conventional mosquito control aerosol product (hereinafter simply referred to as a "conventional product"), when the aerosol-forming material is sprayed into a treatment space, particles M thereof having a particle size of less than 10 pm are diffused in the treatment space. After a while from the spraying, the particles M are further diffused in the entire treatment space, so that the insect pest control component is present throughout the treatment space. As a result, mosquitoes flying in the treatment space can be knocked down or killed. As described above, however, mosquitoes are sitting on an exposed portion in a treatment space longer than flying. Therefore, the conventional product cannot reliably knock down or kill mosquitoes that are sitting on an exposed portion in a treatment space. Also, if, for example, a window of a treatment space is opened, so that wind blows into the treatment space, a portion of the particles M suspended in the treatment space are forced to leave the treatment space by the wind, and therefore, the effect of the insect pest control component is significantly reduced.

Furthermore, if the particles M are suspended in a treatment

space for a longer period of time, a human or pet in the treatment space inhales an increased amount of the particles

M, and is likely to be adversely affected. With the above

in mind, the present inventors have developed a novel

mosquito control aerosol product that solves the above

problems. Sprayed particles that are a characteristic

feature of the mosquito control aerosol product of the

present invention will be described below.

[0057]

[Sprayed Particles]

As shown in FIG. 2(b), when the aerosol-forming material

is sprayed into a treatment space once, sprayed particles R

are formed from the aerosol-forming material. The sprayed

particles R quickly move and adhere to an exposed portion in

the treatment space. Here, a portion of the sprayed particles

R that adhere to the exposed portion are referred to as

"particles X" (in FIG. 2(b), the particles X are represented

by open circles, and mean that "a portion of the sprayed

particles R that adhere to the exposed portion") . Meanwhile, a

portion of the sprayed particles R that are drifting in the

treatment space without adhering to an exposed portion are

referred to as "particles Y" (in FIG. 2(b), the particles Y

are represented by closed circles, and mean that "a portion of

the sprayed particles R that are drifting in the treatment

space without adhering to an exposed portion"). In order to

allow the sprayed particles R to move and adhere to an exposed

portion (i.e., the sprayed particles R are present as the particles X), the sprayed particles R preferably have a particle size of 10 to 80 pm, where the particle size is a d90 particle size in a volume cumulative distribution of the sprayed particles R as measured at a distance of 15 cm from the spray outlet at 250C. Within such a range, the sprayed particles R sprayed into a treatment space reliably move and adhere to an exposed portion in the treatment space, resulting in the particles X as shown in FIG. 2 (b). As a result, mosquitoes sitting on the exposed portion can be knocked down or killed by the insect pest control component of the sprayed particles. The insect pest control effect is also effective to mosquitoes which have entered the treatment space and are trying to sit on an exposed portion, and therefore, the mosquitoes can be driven out of the treatment space. If the particle size of the sprayed particles R is less than 10 pm, the particle size is excessively small, so that the amount of the sprayed particles R which reach an exposed portion decreases. Therefore, it is difficult to control mosquitoes that are sitting or are trying to sit on an exposed portion.

Meanwhile, if the particle size exceeds 80 pm, the particle

size is excessively large, so that it is difficult to control

behavior of the sprayed particles R, and therefore, it is

difficult for the sprayed particles R to appropriately adhere

to an exposed portion. The sprayed particles R more preferably

have a particle size of 25 to 70 pm, where the particle size

is a d90 particle size in a volume cumulative distribution of the sprayed particles R as measured at a distance of 15 cm from the spray outlet at 250C. Although in FIG. 2(b), the particles X and Y are represented by open and closed circles, respectively, for the sake of convenience, in order to distinguish the particles X and Y from each other, both of the particles X and Y are the same particles that are derived from the sprayed particles R. Note that in this embodiment, the d90 particle size of sprayed particles of the mosquito control aerosol in a volume cumulative distribution of the sprayed particles R at a distance of 15 cm from the spray outlet at 250C was measured using Spraytec (STP5321, manufactured by Malvern Panalytical Ltd.).

[00581

Also, the amount of the sprayed particles R adhering to

an exposed portion in a treatment space is preferably 0.01 to

0.4 mg per square meter of the exposed portion, more

preferably 0.05 to 0.2 mg per square meter. Within such a

range, mosquitoes sitting on the exposed portion can be

effectively knocked down or killed. If the amount of the

adhering sprayed particles R is less than 0.01 mg per square

meter, the insect pest control effect is not sufficient for

mosquitoes sitting on the exposed portion, i.e., it is

difficult to knock down or kill the mosquitoes. Meanwhile, if

the amount of the adhering sprayed particles R exceeds 0.4 mg

per square meter, the insect pest control effect is not

significantly improved, and the amount of the aerosol-forming material that is consumed is excessively large, resulting in economic disadvantage.

[00591

Note that the particles Y can also exhibit the insect

pest control effect on mosquitoes as with the particles X.

Although the particles Y cannot knock down or kill mosquitoes

sitting on an exposed portion, the particles Y can

effectively knock down or kill mosquitoes flying in a

treatment space. Also, the particles Y can have an effect on

mosquitoes trying to enter a treatment space and thereby

inhibiting mosquitoes from entering the treatment space.

Thus, the sprayed particles R sprayed in a treatment space

are present in the form of the particles X or Y, and can

utilize these forms to effectively knock down or kill

mosquitoes in the treatment space.

[00601

As described above, immediately after the aerosol

forming material is sprayed into a treatment space once, some

of the sprayed particles R quickly move toward an exposed

portion in the treatment space and adhere to the exposed

portion (particles X), and the other particles are drifting in

the treatment space without adhering to an exposed portion

(particles Y). After a while from the spraying performed once,

the particles X maintain the adhesion to the exposed portion,

and can knock down or kill mosquitoes sitting on the exposed

portion using the insect pest control component. Meanwhile,

the particles Y are progressively diffused throughout the treatment space, and the insect pest control component is gradually vaporized and/or diffused to knock down or kill mosquitoes flying in the treatment space. The particles Y can also prevent mosquitoes trying to enter the treatment space from entering the treatment space. Even if mosquitoes have successfully entered the treatment space, then when the mosquitoes sit on or approach an exposed portion in the treatment space, the mosquitoes can be reliably knocked down or killed by the insect pest control component of the particles X adhering to the exposed portion. Thus, according to the mosquito control aerosol of the present invention, the sprayed particles R sprayed from the spray outlet are present in an optimum state (the states of the particles X and Y), whereby the insect pest control effect can be exhibited at a maximum level. Therefore, the mosquito control aerosol of the present invention is a useful product that can exhibit a good control effect on both mosquitoes which are present in a treatment space and mosquitoes which are trying to enter a treatment space.

[0061]

Also, when wind blows into a treatment space, then even

if a portion of the particles Y are forced to leave the

treatment space by the wind, the particles X adhering to an

exposed portion are present. As described above, most of

mosquitoes in a treatment space are sitting on an exposed

portion longer. Therefore, if the particles X can exhibit the desired effect, then even when the amount of the particles Y is reduced, the effect of controlling mosquitoes does not deteriorate. Furthermore, in the conventional product, substantially all the sprayed aerosol-forming material are diffused into a treatment space, but this is not the case for the mosquito control aerosol of the present invention. The concentration of the insect pest control component (of the particles Y) diffused in a treatment space deceases proportionately with the amount of the particles X, and therefore, is low compared to the conventional product.

Therefore, the influence of inhalation of the insect pest

control component on a human or pet is reduced, and therefore,

the mosquito control aerosol of the present invention can be

provided as a safe product.

[0062]

When the aerosol-forming material is sprayed by the

mosquito control aerosol of the present invention into a

treatment space once, the effect of the insect pest control

component is preferably sustained for 18 hours or more, more

preferably 20 hours or more, in a space of 33.3 m3 or less.

The space of 33.3 m 3 or less includes living spaces of 4.5 to 8

Jyos (a ceiling height of 2.5 m). Therefore, when the mosquito

control aerosol of the present invention is used in typical

living spaces of ordinary homes, the insect pest control

effect can be sustained substantially all day. Mosquitoes

enter indoors night and day. In particular, it is necessary to prevent mosquitoes from sucking blood from a human or pet when they are asleep. The mosquito control aerosol of the present invention can sustain the effect of the insect pest control component over 20 hours or more. Therefore, for example, if the mosquito control aerosol of the present invention is sprayed once before a human or pet goes to bed at night, the effect is sustained until the afternoon of the following day, and therefore, the human or pet can sleep with an easy mind.

[00631

<Mosquito Control Method>

The mosquito control method of the present invention is

performed using the above mosquito control aerosol. The

mosquito control aerosol includes: a pressure-resistant

container equipped with a fixed-amount spray valve, that

contains an aerosol-forming material including transfluthrin

and/or metofluthrin as an insect pest control component and a

lower alcohol and/or a hydrocarbon solvent as an organic

solvent, and a propellant; and a spray button having a spray

outlet connected to the fixed-amount spray valve. When the

spray button is pressed once, the aerosol-forming material is

sprayed in the form of the sprayed particles R from the spray

outlet into a treatment space (spraying step). At this time,

as shown in FIG. 2(b), some of the sprayed particles R quickly

move toward an exposed portion in the treatment space and

adhere to the exposed portion (particles X), and the other

particles are drifting in the treatment space without adhering to an exposed portion (particles Y). The particles X of the sprayed particles R knock down or kills mosquitoes sitting on a wall surface, a floor surface, a surface of an object, etc., in the treatment space, or are also effective to mosquitoes trying to sit on these places, i.e., drive the mosquitoes out of the treatment space. Meanwhile, the particles Y of the sprayed particles R can knock down or kill mosquitoes flying in the treatment space, and are also effective to mosquitoes trying to enter the treatment space, i.e., reduce entrance into the treatment space. The above insect pest control effect of the sprayed particles R is sustained over as long as 18 hours or more, preferably 20 hours or more, in a space of 33.3 m 3 or less. After a predetermined period of time has passed, the aerosol-forming material may be sprayed into the treatment space again to continually knock down or kill mosquitoes.

[0064]

As described above, the mosquito control aerosol of the

present invention is sustained for 18 hours or more,

preferably 20 hours or more, i.e., substantially a day, in a

space of 33.3 m 3 or less. Therefore, when the mosquito control

method performed using the mosquito control aerosol is

employed, the operation can be completed only by performing

the spraying step once a day at a fixed time every day.

Thus, anyone can easily spray the aerosol-forming material

into a treatment space, and can be prevented from missing

the timing to spray.

Examples

[00651

In order to verify the operational stability of the

fixed-amount spray valve after repeated use, and the mosquito

control effect, of the mosquito control aerosol of the present

invention, a plurality of mosquito control aerosols (Examples

1 to 13) having characteristic features of the present

invention were prepared and tested. For comparison, mosquito

control aerosols (Comparative Examples 1 to 6, and Reference

Examples 1 and 2) which have none of the characteristic

features of the present invention were prepared, and similar

tests were conducted.

[00661

The mosquito control aerosols of Examples 1 to 13 were

formulated according to compositions and conditions shown in

Table 1. Tests described below were conducted. Note that: in

Example 2, IPM (15% by weight) was added as an anti

susceptibility reduction aid; in Example 3, 1,3-butylene

glycol (15% by weight) was added as an anti-susceptibility

reduction aid; and in Example 5, IPM (10% by weight) was added

as an anti-susceptibility reduction aid. The mosquito control

aerosols of Comparative Examples 1 to 6 and Reference Examples

1 and 2 were also formulated according to compositions and

conditions shown in Table 1. Tests similar to those for

Examples 1 to 13 were conducted. Note that in all of the

mosquito control aerosols, acrylonitrile butadiene rubber was used as a material for the stem rubber of the fixed-amount spray valve. In the mosquito control aerosols of Comparative

Examples 1 and 2, the spring was a conventional spring ("A" in

Table 1, wire diameter: 0.55 mm, shear modulus: 6.85 x 104,

central diameter: 3.15 mm, effective number of turns: 7.75,

and spring constant: 3.24 N/mm). In the mosquito control

aerosols of Examples 1 to 13, Comparative Examples 3 to 6, and

Reference Examples 1 and 2, the spring was a reinforced spring

("B" in Table 1, wire diameter: 0.6 mm, shear modulus: 6.85 x

104, central diameter: 3.2 mm, effective number of turns: 8,

and spring constant: 4.23 N/mm).

[0067]

[Table 1]

Mosquito control aerosol (30 mL) Spray Amount of insect Aerosol-forming material (a) (wt%) Propellant Volume Spring volume pest control ratio (mL) component control component Organic solvent Others (b) (a/b) sprayed (mg) transfluthrin ethanol LPG 30/70 B 0.2 16.4 27.3 balance P 1

2 transfluthrin ethanol IPM LPG 30/70 B 0.2 16.3 27.3 balance 15 3 transfluthrin ethanol 1,3-butylene LPG 30/70 B 0.2 16.4 27.3 balance glycol 15 DME 4 transfluthrin IPA LPG 30/70 B 0.2 16.2 27.3 balance

5 transfluthrin IPA IPM LPG 30/70 B 0.4 17.0 14.2 balance 10

6 transfluthrin ethanol - LPG 10/90 B 0.4 10.9 27.3 balance C transfluthrin ethanol surfactant LPG 45/55 B 0.2 24.5 E 7 LG 4/5 B 022. M 27.3 balance 0.5 8 transfluthrin ethanol - LPG 20/80 B 0.1 8.4 41.0 balance

9 transfluthrin IPA - PG 20/80 B 1.0 16.0 8.0 balance

10 transfluthrin neothiozole - LPG 30/70 B 0.2 16.4 27.3 balance metofluthrin ethanol - LPG 6/94 B 1.0 24.6 41.0 balance

12 metofluthrin ethanol LPG 30/70 B 0.2 16.4 27.3 balance metofluthrin IPA -PG 20/80 B 0.2 10.9 I1 27.3 balance transfluthrin IPA -PG 30/70 A 0.2 16.2 27.3 balance

2 transfluthrin ethanol surfactant LPG 45/55 A 0.2 24.6 -U 27.3 balance 0.5

taf r methyl ethyl a 3 ketone - LPG 30/70 B 0.2 16.2 e 27.3 balance

transfluthrin ethanol E 41.0 balance

O 5 transfluthrin ethanol LPG 60/40 B 0.2 16.9 14.2 balance

6 transfluthrin ethanol LPG 50/50 B 0.06 14.5 41.0 balance

1 profluthrin 200bl ac1 ethanol LPG 30/70 B 0.2 12.1 CLo 20.0 balance 2 profluthrin ethanol IPM LPG 30/70 B 0.2 12.3 d 2 20.0 balance 10

[0068]

(1) Operational Stability of Fixed-Amount Spray Valve

after Repeated Use

Each test mosquito control aerosol was repeatedly used,

and the un-biased state to which the spray button returns after being pressed down was investigated, whereby the operational stability of the fixed-amount spray valve after repeated use was assessed using the following assessment criteria.

a: No change in the un-biased state of the spray

button after being used at least 20 times

b: A deterioration in the un-biased state of the spray

button after being used 3 to 7 times

c: A significant deterioration in the un-biased state of

the spray button after being used 1 or 2 times

[00691

(2) Control Effect on Adult Mosquitoes

The mosquito control aerosol was sprayed once diagonally

upward at the center of a closed 25-M 3 room. Immediately after

that, 50 adult female Culex pipiens mosquitoes were released

and then exposed for two hours before all of the test

mosquitoes were collected. In the meanwhile, the number of

adult female Culex pipiens mosquitoes which fell down to be

flat on their back as time passed was counted to calculate the

KT 5 o value (min). Thereafter, in the same room, a similar

operation was performed 12 hours and 18 hours after the

mosquito control aerosol was sprayed once. In Examples 1 to

10, Comparative Examples 1 to 6, and Reference Example 1 and

2, two types of adult female Culex pipiens mosquitoes, i.e., a

pyrethroid-susceptible strain and a pyrethroid-resistant

strain, were used. In Examples 11 to 13, only a pyrethroid susceptible strain of adult female Culex pipiens mosquitoes was used.

[0070]

(3) Proportion of Sprayed Particles Remaining in Air

The mosquito control aerosol was sprayed once diagonally

upward toward the center of a closed 25-M 3 room. An air

collection tube (a glass tube filled with silica gel, with

both ends thereof plugged with absorbent cotton) was placed 50

cm back from the center of the room (at a distance of 130 cm

from the wall surface) and 120 cm above the floor, and

connected to a vacuum pump, to suck a predetermined amount of

air after two hours had passed since the spraying. The air

collection tube was washed with acetone. The amount of the

collected insect pest control component was analyzed by gas

chromatography (model no. GC1700, manufactured by Shimadzu

Corporation) . The concentration (by weight) of the insect pest

control component in the air was calculated based on the value

obtained by the analysis. The ratio of this concentration to

the theoretical concentration in the air was calculated as the

proportion of the insect pest control component remaining in

the air.

[0071]

The test results of (1) to (3) are shown in Table 2.

[0072]

[Table 2]

Proportion d90 Mosquito control effect (KT5 0 : min) Operational Opail remaining in particle Susceptible strain Resistant strain air (%) size (Pm) 2h 12h 18h 2h 12h 18h

1 a 0.71 57 5.3 8.2 20.4 5.8 12.1 28.6

2 a 0.84 63 5.3 8.1 15.6 5.5 8.8 20.1

3 a 1.2 56 5.4 8.2 14.9 5.6 9.0 19.3

4 a 0.96 65 6.0 10.4 23.5 6.6 14.3 32.0

5 a 1.3 60 6.2 9.3 17.7 6.5 10.2 23.4

e 6 a 2.3 20 5.9 9.5 25.0 6.0 14.6 35.6 C. E 7 a 0.8 71 4.7 7.6 18.6 5.7 11.9 26.8 8 a 1.9 58 6.7 9.8 25.0 6.9 15.5 33.5

9 a 2.1 62 6.9 10.8 25.2 7.1 14.7 34.0

10 a 1.4 68 7.0 11.5 28.3 8.1 17.2 38.8

11 a 4.5 13 6.5 9.7 35.3 - -

12 a 0.86 62 6.2 9.3 18.0

13 a 1.5 65 7.5 11.3 25.5 - -

1 b 0.96 60 6.2 10.6 24.6 6.8 15.2 35.3

E 2 b 1.1 64 4.8 7.9 19.2 5.9 12.4 27.9

3 c 0.87 59 7.2 18.5 >120 8.2 32.3 >120

4 a 5.7 9 8.1 >120 >120 10.4 >120 >120 01 E 0 5 a 0.06 90 7.5 >120 >120 10.1 >120 >120

6 a 0.13 83 8.2 >120 >120 10.7 >120 >120

S 1 a 0.95 51 7.5 16.4 39.0 8.0 25.6 >120

x 2 a 0.94 54 7.3 15.9 37.5 7.9 24.8 >120

[0073]

In all of Examples 1 to 13, in which a reinforced spring

having a spring constant of 3.3 N/mm or more was used in the

fixed-amount spray valve, there was no change in the un-biased

state to which the spray buttons returns after being pressed

down, after being used 20 times or more, and the operational stability of all of the fixed-amount spray valves after repeated use was good. Meanwhile, in Comparative Examples 1 and 2, in which a conventional spring having a spring constant of less than 3.3 N/mm was used in the fixed amount spray valve, the un-biased state to which the spray button returns after being pressed down deteriorated after being used 3 to 7 times, and the operational stability of the fixed-amount spray valve after repeated use was not said to be significantly good. In addition, even in the case where a reinforced spring having a spring constant of 3.3 N/mm or more was used and methyl ethyl ketone was used as the organic solvent as in

Comparative Example 3, the un-biased state to which the spray

button returns after being pressed down deteriorated

significantly after being used 1 or 2 times, likely leading to

spray failure. This may be because methyl ethyl ketone

degraded acrylonitrile butadiene rubber, resulting in a

decrease in the elasticity of the stem rubber. This indicates

that the suitability of a material of stem rubber for the

organic solvent is of critical importance. It was demonstrated

that even in the case where a reinforced spring having a

spring constant of 3.3 N/mm or more is used, then if the

organic solvent has an adverse influence on acrylonitrile

butadiene rubber, the operational stability of the fixed

amount spray valve after repeated use cannot be improved.

[0074]

As to the effect of controlling adult mosquitoes, it was verified that in Examples 1 to 13, the KT 5 o value was maintained at a significant level, i.e., a good control effect was exhibited, even 18 hours after the mosquito control aerosol containing transfluthrin and/or metofluthrin as an insect pest control component was sprayed once. In Example

1, in which ethanol was used as the organic solvent, Example

4, in which isopropanol was used as the organic solvent,

and Example 10, in which neothiozole was used as the

organic

solvent, the same amount of transfluthrin was contained. In

Examples 1 and 4, the mosquito control effect was good.

Particularly in Example 1, the mosquito control effect was

better. It was thus found that as the organic solvent used in

combination with transfluthrin as an insect pest control

component, lower alcohols having two or three carbon atoms

(ethanol or isopropanol), of the lower alcohol and/or

hydrocarbon solvent, are effective, and in particular, ethanol

is more effective.

[0075]

Furthermore, in Example 1, in which no anti

susceptibility reduction aid was added, and Examples 2 and 3,

in which an anti-susceptibility reduction aid was added, the

same amount of transfluthrin was contained. The reduction in

control efficacy for pyrethroid-resistant strains of Culex

pipiens having reduced susceptibility to a pyrethroid compound

compared to control efficacy for pyrethroid-susceptible

strains was smaller in Examples 2 and 3 than in Example 1.

Thus, it was verified that the addition of a higher fatty acid

ester such as isopropyl myristate or a glycol having 3 to 6

carbon atoms such as 1,3-butylene glycol, as an anti

susceptibility reduction aid, is significantly effective in

controlling pyrethroid-resistant strains of mosquitoes. Note

that in Reference Examples 1 and 2, in which profluthrin was

used as the insect pest control component, the effect

of controlling pyrethroid-resistant strains of Culex pipiens

was significantly poor compared to the effect of

controlling pyrethroid-susceptible strains, and this

reduction was not reduced even in the case where isopropyl

myristate was added. Therefore, it was demonstrated that

transfluthrin is still effective to pyrethroid-resistant

strains of mosquitoes, and higher fatty acid esters such

isopropyl myristate and as

glycols having 3 to 6 carbon atoms such as 1,3-butylene

glycol, when used in combination with transfluthrin as an

insect pest control component, are specifically useful as an

anti-susceptibility reduction aid.

[0076]

Meanwhile, in Comparative Example 3, in which methyl

ethyl ketone was used as the organic solvent, the KT 5 o value

was 120 minutes or more 18 hours after the mosquito control

aerosol was sprayed once, i.e., the effect of controlling

mosquitoes did not last over a long period of time. In

Comparative Examples 4 and 5, in which the volume ratio (a/b)

of the aerosol-forming material (a) to the propellant (b) was out of the range of 6/94 to 50/50, and Comparative Example 6, in which the spray amount as the spray button is pressed down once was out of the range of 0.1 to 1.0 mL, the KT5 o value was

120 minutes or more 12 hours after the mosquito control

aerosol was sprayed once, i.e., the effect of controlling

mosquitoes did not last over a long period of time.

INDUSTRIAL APPLICABILITY

[0077]

According to the present invention, a mosquito control

aerosol having a significant effect of controlling mosquitoes,

and a mosquito control method using this, can be provided.

REFERENCE SIGNS LIST

[0078]

10 VALVE MECHANISM

11 STEM

12 STEM RUBBER

13 SPRING (REINFORCED SPRING)

20 HOUSING

21 FIXED-AMOUNT CHAMBER

100 FIXED-AMOUNT SPRAY VALVE

R SPRAYED PARTICLES X SPRAYED PARTICLES ADHERING TO EXPOSED PORTION Y SPRAYED PARTICLES DRIFTING IN TREATMENT SPACE

Claims (10)

1. A mosquito control aerosol comprising:

a pressure-resistant container containing an aerosol

forming material including transfluthrin and/or metofluthrin,

which are an insect pest control component, and a lower

alcohol and/or a hydrocarbon solvent, which are an organic

solvent, and a propellant;

a fixed-amount spray valve having a valve mechanism

including a stem, a stem rubber, and a spring, and a housing

for the valve mechanism, wherein the fixed-amount spray valve

is attached to an open part of the pressure-resistant

container; and

a spray button having a spray outlet connected to the

fixed-amount spray valve,

wherein

the volume ratio (a/b) of the aerosol-forming material

(a) to the propellant (b) is 6/94 to 50/50,

a material for the stem rubber is acrylonitrile

butadiene rubber,

the spring is a reinforced spring,

the volume of the aerosol-forming material sprayed when

the spray button is pressed down once is 0.1 to 1.0 mL, and

sprayed particles sprayed from the spray outlet have a

particle size of 10 to 80 pm, where the particle size is a d90 particle size in a volume cumulative distribution of the sprayed particles as measured at a distance of 15 cm from the spray outlet at 25°C.

2. The mosquito control aerosol according to claim

1, wherein

the reinforced spring has a spring constant of 3.3 N/mm

or more.

3. The mosquito control aerosol according to claim 1

or 2, wherein

the insect pest control component is transfluthrin.

4. The mosquito control aerosol according to any one

of claims 1 to 3, wherein

when the aerosol-forming material is sprayed into a

treatment space once, the proportion of the insect pest

control component remaining in the air after two hours have

passed is 0.05 to 5%, and a period of time during which an

effect of the insect pest control component is sustained is 18

hours or more in a space of 33.3 m 3 or less.

5. The mosquito control aerosol according to any one

of claims 1 to 4, wherein

the sprayed particles sprayed from the spray outlet have

a particle size within the range of 25 to 70 pm, where the particle size is a d90 particle size in a volume cumulative distribution of the sprayed particles as measured at a distance of 15 cm from the spray outlet at 250C.

6. The mosquito control aerosol according to any one

of claims 1 to 5, wherein

the volume of the aerosol-forming material sprayed when

the spray button is pressed down once is 0.1 to 0.2 mL.

7. The mosquito control aerosol according to any one

of claims 1 to 6, wherein

the amount of the insect pest control component sprayed

when the spray button is pressed down once is 5.0 to 30 mg per

treatment space of 18.8 to 33.3 M 3 .

8. The mosquito control aerosol according to any one

of claims 1 to 7, wherein

the organic solvent is a lower alcohol having two or

three carbon atoms.

9. The mosquito control aerosol according to any one

of claims 3 to 8, wherein

the aerosol-forming material contains, as an anti

susceptibility reduction aid for transfluthrin, a higher fatty

acid ester having a total of 13 to 20 carbon atoms and/or a

glycol having 3 to 6 carbon atoms.

10. A mosquito control method for knocking down or

killing mosquitoes, comprising:

using the mosquito control aerosol according to any one

of claims 1 to 9 to spray the aerosol-forming material into a

treatment space.