JPH11103750A - Liquid sucking wick of porous material and thermal volatilization of chemical using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide both a liquid sucking wick of a porous material excellent in all aspects of physical properties such as strength properties, chemical stability, uniformity in production or heat conductivity related to volatilization performances as compared with those of a conventional liquid sucking wick and a method for thermal volatilization by which stable volatilization performances and excellent insecticidal efficacies are produced by using the liquid sucking wick of the porous material. SOLUTION: This liquid sucking wick 3 of a porous material is obtained by baking and bonding ceramic grains made of a material having <=0.02 cal/ cm.sec. deg.C heat conductivity at 20 deg.C as a main raw material, especially the ceramic grains made of mullite as a material. The method for thermal volatilization of a chemical using the liquid sucking wick 3 of the porous material comprises sucking an agent 4 containing 0.3-5.0 wt.% pyrethroid compound into the liquid sucking wick 3 of the porous material, heating the liquid sucking wick 3 of the porous material and volatilizing the chemical.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous liquid absorbent core and a method for heating and evaporating a drug using the same.

[0002]

2. Description of the Related Art Hitherto, as a method of heating and evaporating a drug for the purpose of killing insects, (1) a so-called mosquito coil and (2) an electric mosquito mat have been favored. In addition, the method of immersing a porous absorbent core in a drug solution and heating the core to heat and evaporate the drug does not require a mat or the like to be replaced each time, and the effect is stable for a long time. It is popular for reasons. Conventionally, oil-based chemicals based on petroleum have been mainly used for this heat-evaporation chemical, but aqueous chemicals using water as a solvent for the purpose of eliminating the danger to fire in recent years and further enhancing insecticidal efficacy have also been marketed. I have. By the way, as the liquid absorbing core, for example, at least one kind of mineral powder selected from activated clay, diatomaceous earth, talc, clay, perlite, etc. is hardened using a paste such as dextrin, starch, carboxymethyl cellulose. Thing (Tokkyo Sho 59-4
No. 0409) or a mixture obtained by firing a mixture comprising an inorganic powder, an organic substance and an inorganic binder at 600 to 2000 ° C. (Japanese Patent Laid-Open No. 4-117303).
There is known a fiber absorbent layer comprising a fiber absorbent layer and a holding material layer whose periphery is coated with a silicone varnish (Japanese Patent Application Laid-Open No. Hei 5-328888). However, the absorbent core using a paste is an aqueous chemical. Naturally, when immersed in water, the dissolution, elution, and swelling of the paste cause physical deterioration of the absorbent core, so it cannot be applied to aqueous chemicals, and the absorbent core formed by firing a mixture containing inorganic powder or In the case of a liquid absorbent core using a fiber liquid absorbent layer, any of the currently available products, such as coloring of the chemical solution with aging and requiring strict technology in the manufacturing process to control the evaporation performance, are required. At present, the liquid absorbent wick is not completely satisfactory.

[0003]

DISCLOSURE OF THE INVENTION The present inventors have found that a porous liquid-absorbing core formed by partially firing and bonding ceramic particles made of alumina or the like partially into a vitreous material has an organic porous structure. Compared to the body, it has been found that it is superior in strength and chemical stability and is more suitable for the chemical heating and evaporation method that requires fine control of the amount of volatilization because the pore diameter of the gap is more uniform. However, these porous liquid absorbent cores have high thermal conductivity, so that the temperature of the heat receiving portion is diffused throughout the liquid absorbent core, and there is a concern that the evaporation performance of the active ingredient may be affected depending on the use conditions. The present invention relates to a system in which a porous liquid absorbent core is immersed in a chemical solution containing a pyrethroid compound as an active ingredient, and the upper portion of the core is heated to evaporate the drug. It is an object of the present invention to provide a porous liquid absorbent core exhibiting the above and a method of heating and evaporating a drug using the same.

[0004]

In order to achieve the above object, according to the first aspect of the present invention, the thermal conductivity at 20.degree.
The present invention relates to a porous liquid absorbent core obtained by firing and bonding ceramic particles mainly composed of a material of 02 cal / cm · sec · ° C. or less. Here, the thermal conductivity at 20 ° C. is 0.02 cal.
Examples of the material having a temperature of not more than / cm · sec · ° C include mullite and cordierite. Ceramic particles using these materials have lower thermal conductivity than alumina particles and are more suitable for the present chemical heating and evaporation method. It became clear that there was. In the present invention, the particle size of the ceramic particles to be used, firing, bonding conditions and the like are appropriately selected, various physical properties, it is possible to produce a porous liquid absorbent core of specifications, for example, as long as it meets the gist of the present invention, A small amount of ceramic particles having a thermal conductivity of more than 0.02, cal / cm · sec · ° C. may be blended. The pore diameter of the ceramic particles is preferably 0.2 to 50 μm in terms of the evaporation performance.

According to a second aspect of the present invention, in the first aspect, the thermal conductivity at 20 ° C. is 0.02 cal / cm · cm.
A particularly useful mullite was selected as a material having a temperature of less than seconds / ° C.

According to a third aspect of the present invention, in the configuration of the first or second aspect, a vitreous material is partially added, followed by firing and bonding. By adding vitreous, the porous liquid absorbent core is more advantageous in terms of strength and uniformity of the gap.

According to a fourth aspect of the present invention, a liquid containing a pyrethroid compound in an amount of 0.3 to 5.0% by weight is absorbed into a liquid absorbing core.
In the drug heating and evaporation method in which the liquid absorbent core is heated to evaporate the drug, the ceramic particles mainly composed of a material having a thermal conductivity of not more than 0.02 cal / cm · sec · ° C. at 20 ° C. Preferably, a porous liquid absorbent core obtained by firing and bonding ceramic particles made of mullite as a raw material, and more preferably, a chemical heating using a porous liquid absorbent core formed by firing and bonding partially by adding vitreous material. It relates to the transpiration method.

The pyrethroid compound used in the present invention has a vapor pressure at 20 ° C. of 4.0 × 10 ⁻⁶ mm.
Cyclopropanecarboxylic acid ester compounds having an Hg or higher, for example, arethrin, framethrin, praletrin, 5-propargyl-2-furylmethyl 2,2,2
3,3-tetramethylcyclopropanecarboxylate (hereinafter, referred to as compound X), 5-propargyl-2-methyl-3-furylmethyl 2,2,3,3-tetramethylcyclopropanecarboxylate (hereinafter, compound Y) ), Empentrin, fenfluthrin, transfluthrin and the like, but are not limited thereto. When an optical isomer or a geometric isomer based on the asymmetric carbon of the acid portion or the alcohol portion exists, it is a matter of course that the isomer alone or an arbitrary mixture thereof is also included in the present invention. . In the present invention, one or two of these active ingredients are contained in a chemical solution at a concentration of 0.1%.
It is contained in an amount of 3 to 5.0% by weight. If it is less than 0.3%, the insecticidal effect is insufficient, while if it exceeds 5.0% by weight, clogging may occur in the liquid absorbent core, which is problematic.

The chemical used in the present invention may be an oily chemical in which the active ingredient is dissolved in a petroleum solvent such as normal paraffin, isoparaffin or naphthenic hydrocarbon.
A so-called aqueous chemical solution in which water as an active ingredient and a solvent is solubilized using a surfactant is preferable in that the problem of flammability can be solved and the insecticidal effect can be enhanced as compared with an oil-based chemical solution.

[0010] The chemical solution is filled into a plastic drug solution container loaded with the above-mentioned liquid-absorbing wick, and then used through an appropriate heating and evaporating apparatus to constitute the heating and evaporating method of the present invention.

In a fifth aspect of the present invention, in the configuration of the fourth aspect, an aqueous chemical is used as the chemical.

According to a sixth aspect of the present invention, in the configuration of the fifth aspect, (a) a pyrethroid compound as an active ingredient is used.
0.3 to 5.0% by weight, and (b) one or more surfactants which evaporate at a heating temperature of 100 to 180 ° C.
An aqueous chemical solution containing 0.0 to 80.0% by weight and (c) water is used.

The aqueous chemical solution contains 10.0 to 80.0% by weight of one or more surfactants which evaporate at a heating temperature of 100 to 180 ° C. in addition to the pyrethroid compound. The amount of the surfactant is preferably 45.0.
７５75.0% by weight, which can be arbitrarily determined as long as the properties of the aqueous drug solution are not impaired.

The surfactant used in the present invention includes:
Non-ionic ones are preferred, for example, the general formula I: R—O— (C ₂ H ₄ O) m · (C ₃ H ₆ O) n · H (I) (wherein R has 1 carbon atom) And m and n each represent an integer of 0 to 6, provided that m + n is 1 to 6.
A polyoxyalkylene alkyl ether compound represented by the general formula II: (Wherein, R ′ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, m and n each represent an integer of 0 to 6, where m + n is an integer of 1 to 6). Polyoxyalkylene phenyl ether compound, general formula II
I: a polyoxyethylene fatty acid ester represented by R-COO- (CH ₂ CH ₂ O) m · H (III) (wherein R and m represent the same meaning as described above), and a general formula IV or V: (Wherein, R represents the same meaning as described above) represented by the general formula VI or VI
I: (Wherein R ₁ , R ₂ and R ₃ represent an alkyl group having 1 to 8 carbon atoms or a phenyl group in which one hydrogen atom may be substituted with an alkyl group having 1 to 3 carbon atoms). Polyhydric alcohol partial ethers of the general formula VIII: (In the formula, l, m, and n represent an integer of 0 to 8, provided that l +
n is an integer of 1 to 8) represented by polyoxyethylene polyoxypropylene glycol, polyoxyethylene polyhydric alcohol fatty acid partial ester, fatty acid alkylol amide, alkane diol such as hexane diol or pentane diol, etc. Although it can be mentioned, it is not limited to these. If necessary, a small amount of another nonionic surfactant, cationic surfactant, anionic surfactant, or zwitterionic surfactant may be added to these surfactants as long as their properties are not impaired. An agent may be blended.

The aqueous drug solution used in the present invention is prepared by adding water to the pyrethroid compound and the surfactant. If necessary, other components such as insecticides, fungicides, repellents, piperonyl butoxy, etc. Synergists for pyrethroids such as side, sinepiline 222, and S-421, and organic solvents as dyes, fragrances, or auxiliaries can be appropriately added. Also,
In order to further improve chemical stability and evaporation performance, dibutylhydroxytoluene (BHT): 3-t-butyl-4
Needless to say, an antioxidant such as -hydroxyanisole, dilauryl-thio-dipropionate, and 2,2'-methylenebis- (6-t-butyl-4-ethylphenol) may be blended.

Further, in order to suppress the coloring of the aqueous chemical solution over time, one or more lozenges such as ethylenediaminetetraacetate and citrate may be blended. Particularly useful salts are disodium ethylenediaminetetraacetate,
Trisodium citrate and the like can be exemplified, and the compounding amount is suitably 0.001 to 0.5% by weight based on the total amount. If the amount is less than 0.001% by weight, the effect of preventing coloration is low. On the other hand, if it exceeds 0.5% by weight, there is a problem in usability such as remarkable precipitation of crystals on the surface of the absorbent core, which is not preferable.

According to a seventh aspect of the present invention, there is provided a method as set forth in any one of the fourth to sixth aspects, wherein the pyrethroid compound is one or two selected from, in particular, arethrin, framethrin, praletrin, compound X and compound Y. It was what was.

According to the invention of claim 8, in the constitution of claim 6 or 7, the general formula I: RO— (C ₂ H ₄ O) m · (C ₃ H ₆ O) which is particularly useful as a surfactant. n · H (I) (wherein, R represents an alkyl group having 1 to 8 carbon atoms, m and n each represent an integer of 0 to 6, provided that m + n is 1 to 6
Or one or more of the polyoxyalkylene alkyl compounds represented by the general formula (1).

Among the surfactants represented by the general formula I, particularly preferred specific examples are as follows, but are not limited thereto, and the aralkyl group in the compound may be in the form of a chain or a chain. Any of the branches is included. Surfactant (1): diethylene glycol monoethyl ether Surfactant (2): diethylene glycol monopropyl ether Surfactant (3): diethylene glycol monobutyl ether Surfactant (4): triethylene glycol monoethyl ether surfactant (5 ): Triethylene glycol monopropyl ether Surfactant (6): Triethylene glycol monobutyl ether

[0020]

DETAILED DESCRIPTION OF THE INVENTION
In this method, ceramic particles mainly made of a material having a thermal conductivity of 0.02 cal / cm · sec · ° C. or less are fired and bonded to produce a liquid-absorbing core. It has excellent strength and chemical stability, and the pore size of the gaps is uniform, and of course, concerns about the high thermal conductivity of alumina etc. There is no effect on transpiration performance). Therefore, in a system in which the porous liquid absorbent core is immersed in the chemical solution and the upper part of the core is heated to evaporate the medicine, regardless of the use conditions, more stable evaporation performance and excellent insecticidal effect can be achieved. In producing the porous liquid absorbent core of the present invention, the conventional ceramic molded article production technology can be directly applied, and a mixture of ceramic particles, an organic binder, and the like,
Preferably, a vitreous component is added, the mixture is temporarily molded using an extruder or a press machine, and then fired and bonded at 1000 ° C. or higher. Prior to firing and bonding,
The temporary molded article can be treated with an aqueous solution such as phosphoric acid or boric acid or a chemical such as organic acid, glycol, or silicone to further stabilize the evaporation performance.

According to the second aspect of the present invention, mullite, which is particularly useful among materials having a thermal conductivity of not more than 0.02 cal / cm · sec · ° C. at 20 ° C., is used, so that the performance is of course better. It is also preferable from the viewpoint of availability.

According to the third aspect of the present invention, since the vitreous component is added to the ceramic particles and fired and bonded, a more useful porous liquid absorbing core can be obtained.

According to the fourth aspect of the present invention, the plastic drug solution container loaded with the porous liquid absorbing core of the present invention having excellent performance is applied to the heating and evaporating apparatus. Is provided. As the heat evaporation device used in the method of heating and evaporating a drug of the present invention, a generally available device can be used arbitrarily, and the structure, specifications and the like are not limited at all, but an example of the device will be described with reference to the accompanying drawings. .

The heating and evaporating apparatus comprises a vessel 1 and a drug solution container 2. The drug solution container 2 has a porous liquid absorbent core 3 projecting from the inside of the vessel to the outside, and is screwed and suspended in a screw portion inside the vessel 1. It has a structure to be bridged. The container 1 is molded using a semi-rigid or rigid synthetic resin, but it may be divided into appropriate parts and assembled to form a required one. Further, the container 1 may be partially provided with a transparent resin or perforated to provide a liquid amount confirmation window so that the liquid amount in the chemical liquid container 2 can be confirmed from outside the apparatus.
Further, an outside air inlet communicating with the outside can be provided in the body or bottom of the container 1, so that the effect of volatilizing the chemical solution by the upward airflow can be enhanced.

The chemical liquid container 2 is made of a chemical resistant synthetic resin such as polypropylene, polyester, polyvinyl chloride, etc., is filled with a chemical liquid 4, and the porous liquid absorbent core 3 is sealed at its mouth via a suitable holding member. After being held in the shape, it is attached to the body 1. As a method of attaching the chemical solution container 2 to the container 1, for example, a method of screwing or fitting to a holder provided on the chemical solution container 2 or a screw-type bottom lid provided on the bottom surface, Or a method in which the container 1 is screwed or fitted to the head of the drug solution container 2 to expose the peripheral surface of the drug solution container 2. In this case, the drug solution container 2 is placed on a pedestal. May be placed and held.

The ring-shaped heating element unit 5 is provided at the center of the top surface of the container 1 so as to surround the upper end of the porous liquid absorbent core 3 with a gap 6 therebetween. When energized, porous liquid absorbent core 3
The portion of the heat generating unit 5 facing the heat radiating ring is 70
Heated to a temperature of about 140 ° C., the radiant heat causes the chemical contained in the porous liquid absorbent core 3 to evaporate into the air from the top opening 7 at the top of the container. In addition, the transpiration efficiency can be improved by providing the transpiration tube which hangs downward from the top surface opening 7 in the vessel 1.

Further, a pilot lamp and the like in addition to the on / off operation switch 8 and the power cord 9 are appropriately provided outside or inside the body 1 of the heating and evaporating apparatus. The power cord 9 may be of an extension cord mounting type, a so-called cordless type in which a plug terminal is fixed to the housing 1, or a storage chamber for housing the power cord 9 may be separately provided in the housing 1. No problem.

According to the chemical heating and evaporating method of the present invention, the chemical liquid 4 that has permeated the heat receiving portion of the porous liquid absorbing core 3 is indirectly heated by the ring-shaped heat generating unit 5 of the heat evaporating apparatus and evaporates.
It exerts a long-term stable and high control effect on mosquitoes, flies, cockroaches, bed bugs, mites and the like.

According to the fifth aspect of the present invention, since the aqueous chemical is used as the chemical, the problem of flammability can be solved and the insecticidal effect can be enhanced.

According to the sixth aspect of the present invention, the composition of the aqueous drug solution is specified to be a preferable compounding composition, so that a more useful drug heat evaporation method is provided.

According to the seventh aspect of the present invention, since a particularly preferable pyrethroid compound is used, it is advantageous in terms of transpiration performance and insecticidal effect.

According to the eighth aspect of the present invention, since a particularly preferable surfactant is used, a more excellent method of heating and evaporating a drug is provided.

[0033]

Next, the present invention will be described in more detail based on examples and test examples, but the present invention is not limited to these examples.

Example 1 Using a mullite particle having a raw material particle diameter of 5 to 10 μm, a porous liquid absorbent core (outer diameter 7.0 mm, length 75.5 mm) having an average pore diameter of 1 to 2 μm was prepared. 45 ml of an aqueous drug solution containing 1.5 wt% of d-cis, trans-flammentoline, 70 wt% of diethylene glycol monobutyl ether, 0.8 wt% of BHT, and purified water is filled into a 50 ml plastic drug solution container and held. The porous body absorbent core was loaded via a tool. After storing the obtained medicinal solution container with a porous absorbent core at 50 ° C. for one month, the properties of the medicinal solution were examined. As a result, the degree of coloring was very slight as compared with the time when the test was started. In addition, the temperature of the heating element unit is set to 140
The apparatus was mounted on a heating and evaporating apparatus at a temperature of ° C. and was energized. The volatilization amount per day (12 hours) was about 0.7 ml over 60 days, and high insecticidal efficacy was maintained without clogging.

Test Example 1 In accordance with Example 1, the liquid-absorbing wick-loaded samples shown in Table 1 were prepared (in the table, in the column of water and other columns in the chemical composition,
"Remaining" means that the remaining weight% is occupied by water or the indicated substance), and the transpiration performance and the insecticidal effect were examined by mounting the apparatus on a commercially available heat evaporation apparatus. The transpiration capacity was determined by trapping a silica gel packed column every predetermined time, extracting the active ingredient with acetone, and analyzing it by gas chromatography to determine the amount of transpiration per hour of the active ingredient. The values are shown as relative ratios when the value is 1.00. On the other hand, regarding the insecticidal efficacy, the reciprocating effect on Culex pipiens was evaluated by the following continuous aeration method.
The relative effective ratio is shown when the initial value of the kerosene solution containing 2.6% by weight of d-cis and trans-aresulin is 1.00. In addition, BHT was added to the chemical solution in an amount of 0.3 to 1.0 times the amount of the pyrethroid compound.

(Continuous ventilation method) Inner diameter 20 cm, height 43 c
m plastic cylinders were stacked in two stages, and the top and bottom were separated by a 16 mesh wire mesh.
A 0-cm cylinder (a place for placing a test mosquito) is placed, and a cylinder having the same diameter and a height of 20 cm is further placed. The four-tiered cylinder is placed on a table, and a heating and evaporation device is placed in the center of the table to evaporate the chemical. Then, about 20 test mosquitoes are released on the upper cylinder,
Observe the number of inversions over time. Twenty minutes after exposure, all test mosquitoes are transferred to a clean polyethylene container, given 3% sugar water, and examined for mortality 24 hours after storage.

[0037]

[Table 1]

[0038] As a result of the test, the chemical heating and evaporation method using the porous absorbent core of the present invention exhibited excellent evaporation performance over a long period of time and maintained a high insecticidal effect. On the other hand, a conventional absorbent core as shown in a control example, for example, one obtained by firing a mixture of an inorganic powder, an organic substance and an inorganic binder (control example 1), a fiber absorbent layer In the case of Comparative Example 2 consisting of a holding material layer coated with a silicone varnish on the periphery thereof, the chemical liquid was somewhat colored over time, and strict production control was required in order to make the evaporation performance uniform. Furthermore, as in Control Example 3, the pyrethroid compound content was
A chemical solution of less than 0.3% by weight has insufficient insecticidal efficacy, while
When the content of the active ingredient was more than 5.0% by weight as in Comparative Example 4, the active ingredient was accumulated in the liquid-absorbent wick, resulting in a decrease in evaporation performance. Therefore, the usefulness of the liquid absorbent core of the present invention is apparent.

[0039]

As described above, the porous liquid absorbent core of the present invention comprises:
Compared with conventional liquid absorbent cores, they are excellent in all aspects such as strength, chemical stability, uniformity in production, and physical properties such as thermal conductivity involved in evaporation performance, and are extremely useful. In addition, the method of heating and evaporating a medicine of the present invention using the porous liquid absorbing core also exhibits more stable evaporation performance and excellent insecticidal efficacy, so that its practicality is extremely high.

[Brief description of the drawings]

FIG. 1 shows a cross-sectional view of one embodiment of a heat evaporation device used in the present invention.

[Explanation of symbols]

 1. Body 2. Chemical solution container 3. 3. Porous liquid absorbent core Chemical solution 5. Ring-shaped heating element unit 6. Gap 7. Top opening 8. On / off operation switch 9. Power cord

Claims (8)

[Claims] 1. Thermal conductivity at 20 ° C. of 0.02 ca
A porous liquid absorbent core obtained by firing and bonding ceramic particles mainly made of a material having a temperature of 1 / cm · sec · ° C or less. 2. The thermal conductivity at 20 ° C. is 0.02 ca.
2. The porous liquid absorbent core according to claim 1, wherein the material having a temperature of 1 / cm.sec..degree. C. or less is mullite. 3. The porous liquid absorbing core according to claim 1, wherein the porous liquid absorbing core is formed by partially adding vitreous material and firing and bonding. 4. A method for heating and evaporating a drug containing 0.3 to 5.0% by weight of a pyrethroid compound into a liquid absorbing core and heating the liquid absorbing core to evaporate the drug. A method for heating and evaporating a drug, wherein the core is the porous liquid absorbent core according to any one of claims 1 to 3. 5. A drug solution containing a pyrethroid compound,
The method for heating and evaporating a drug according to claim 4, wherein the drug is an aqueous drug solution. 6. An aqueous drug solution comprising: (a) 0.3 to 5.0% by weight of a pyrethroid compound as an active ingredient;
6. The composition according to claim 5, further comprising 10.0 to 80.0% by weight of one or more surfactants evaporating at a heating temperature of 0 to 180 [deg.] C., and (c) water. The method of heating and evaporating drugs. 7. The pyrethroid compound is selected from the group consisting of allethrin, framethrin, praletrin, 5-propargyl-2-furylmethyl 2,2,3,3-tetramethylcyclopropanecarboxylate and 5-propargyl-2-methyl-3-furyl. 7. The method according to any one of claims 4 to 6, wherein the method is one or two selected from methyl 2,2,3,3-tetramethylcyclopropanecarboxylate. 8. The surfactant represented by the general formula I: R—O— (C ₂ H ₄ O) m · (C ₃ H ₆ O) n · H (I) (wherein, R has 1 to 1 carbon atoms) And m and n each represent an integer of 0 to 6, provided that m + n represents 1 to 6
The method according to claim 6 or 7, wherein the compound is one or more of polyoxyalkylene alkyl ether-based compounds represented by the following formula: