DESCRIPTION

METHOD FOR ACTIVATING INSECT-CONTROLLING

RESIN ARTICLES

TECHNICAL FIELD

[0001] This application was filed claiming Paris Convention priority of Japanese Patent Application No. 2007-081163, the entire content of which is herein incorporated by reference.

The present invention relates to a technique for enabling the recycle of used insect-controlling resin articles so as to reuse them for control of insects.

BACKGROUND OF INVENTION

[0002] There are widely used insect-controlling resin articles such as coating type articles obtained by coating surfaces of resin articles with insect-controlling agents and incorporation type articles obtained by shaping knead- mixtures of thermoplastic resins with insect-controlling agents. Especially, the incorporation type articles allow the insect-controlling agents to migrate to the surfaces thereof to exhibit the insect-controlling functions, and are able to continue such functions over long periods of time. For example, an ethylene-based resin into which an insect-controlling agent has been incorporated is shaped into fibers, and such fibers are further processed to make nets, which are then made into mosquito nets and insect proof fences (cf . Patent Publications 1 and 2) . [0003] Patent Publication 1: Japanese Patent No. 3756115 Patent Publication 2: Japanese Patent No. 3759739

DISCLOSURE OF INVENTION

[0004] For example, an article made of a resin incorporated with an insect-controlling agent confronts such a problem that the insect-controlling agent contained in the resin article migrates to the surface of the article in use with time, and transpires or adheres to insects which contact the surface of the shaped article, with the result that the insect-controlling agent is lost. The insect-controlling function of the insect-controlling resin article degrades with the loss of the insect-controlling agent. Consequently, the insect-controlling resin article becomes impossible to exhibit its sufficient function. Generally, the article which can not exhibit the sufficient insect-controlling function is scrapped. However, an increasing demand to research methods for recycling such used insect-controlling resin articles has arisen from the viewpoints of effective use of resources and the protection of the environments. [0005] The present inventors have extensively researched resin articles which sustain insect-controlling agents to thereby have insect-controlling functions to be used for controlling insects, i.e., so-called insect-controlling resin articles. The inventors have found out a method for efficiently re-carrying insect-controlling agents on the used insect-controlling resin articles, in the course of such researches. The present invention has been accomplished based on this finding. [0006] The present invention provides a method for activating a used insect-controlling resin article, the method comprising

washing the used insect-controlling resin article, and bringing the resin article into contact with a liquid containing an insect-controlling agent, thereby carrying the insect-controlling agent on the resin article. [0007] In one of preferred modes, the above washing is carried out before bringing the resin article into contact with the liquid containing the insect-controlling agent. In another preferred mode, the resin article is washed with water during the above washing. In a particularly preferred mode for this, the water contains a detergent. In a further preferred mode, the resin article is washed with water during the above washing, and is dried before being brought into contact with the liquid containing the insect-controlling agent. In a further preferred mode, the liquid consists essentially of the insect-controlling agent. In a further preferred mode, the liquid containing the insect-controlling agent is a liquid containing the insect- controlling agent and a solvent. In a further preferred mode, the washing of the resin article and the bringing of the resin article into contact with the liquid containing the insect-controlling agent are carried out simultaneously, In a further preferred mode, the resin article is washed with water containing an insect-controlling agent, and the water containing the insect-controlling agent is the above liquid containing the insect-controlling agent with which the resin article is brought into contact. In a particularly preferred mode for this, the water containing the insect-controlling agent further contains a detergent. In a further preferred mode, the temperature of the above liquid containing the insect-controlling agent when contacting the resin article is room temperature. In a

further preferred mode, the resin article is an article made of a thermoplastic resin. In a more preferred mode for this, the thermoplastic resin is a polyolefin-based resin. In a further preferred mode, the resin constituting the resin article contains a resin having a glass transition temperature of not higher than 10 ⁰ C. [0008] The method for activating a used insect- controlling resin article, according to the present invention, enables the repeated use of an insect- controlling resin article, to thereby contribute to saving of resources and reduction of wastes for protection of the environments. According to the method of the present invention, it becomes possible to carry, on the resin article, an agent which is different from the insect- controlling agent the resin article originally has had therein, or plural kinds of agents.

BEST MODES FOR CARRYING OUT THE INVENTION

[0009] The insect-controlling resin article as used herein includes a resin article having a surface coated with an insect-controlling agent, and an article made of a resin containing an insect-controlling agent. The material, the shape and the kind of the insect-controlling agent for the article are selected in accordance with a concrete application of the article. The insect-controlling agent is gradually released from the article during the use of the article. The used insect-controlling resin article referred to in the present invention is a resin article which has decreased in the amount of a sustained insect- controlling agent and thus has degraded in an insect- controlling function in comparison with the initial

function thereof.

[0010] The method of the present invention comprises washing a used insect-controlling resin article, and bringing the resin article into contact with a liquid containing an insect-controlling agent to thereby carry the insect-controlling agent on the resin article. Dirt on the article is removed by washing so that the contact efficiency between the article and the liquid containing the insect-controlling agent is improved. [0011] The washing method is not limited, and any method may be employed insofar as dirt on the article can be removed. For example, while washing by jetting a gas may be possible, washing by the use of a liquid is generally employed. In a preferred mode, the used resin article is washed with water. In a preferred mode, water containing a detergent is used. The kind of the detergent may be suitably selected in accordance with the kind of a resin constituting the article to be washed, the kind of the dirt on the article, etc. In many cases, a neutral detergent is used. In a particularly preferred mode, a neutral detergent containing a surfactant is used. The washing with a liquid such as water may be done by the hands in a container such as a basin. In a preferred mode, the washing is done in a washing machine with a stirrer such as a household washing machine. For example, an article in the form of yarns, such as a mosquito net, is practically washed with water dissolving a neutral detergent for clothing therein in a household washing machine as described in JIS L0217-103, or in a container such as a basin.

[0012] In the washing with water, the temperature of the

water is preferably from 20 to 50°C, more preferably from 30 to 40°C, from the viewpoints of a cleaning effect and safety. When the method of the present invention is carried out outdoors, solar heat may be utilized to control the water temperature.

[0013] When the washing of the resin article with water is done before the article is brought into contact with the liquid containing the insect-controlling agent, the washed resin article may be dried before the contact with the liquid. While the drying may be done in a drier, preferably, the drying is done in a well ventilated room or outdoors .

[0014] The used resin article is brought into contact with the liquid containing the insect-controlling agent to thereby carry the insect-controlling agent on the resin article. How to allow the insect-controlling agent to be present in the resin article is not limited. Preferably, the insect-controlling agent may be in the form of film coating the surface of the resin article, or may be held in the voids in the interior of the resin article (for example, in the clearances between each of resin yarns when the resin article is a fabric made of the resin yarns, or the inner pores of the article when the article is a porous resin article) , or otherwise, may be dissolved and penetrated into the resin constituting the article so as to be held therein.

[0015] When the melting point of the insect-controlling agent contained in the liquid is lower than the temperature of the liquid during the contact treatment, the liquid may consist essentially of the liquid insect-controlling agent. The liquid containing the insect-controlling agent may be a

solution prepared by dissolving the insect-controlling agent in a solvent or may be a liquid dispersion prepared by dispersing the insect-controlling agent in a liquid medium. The insect-controlling agent in the liquid dispersion may be in the form of a solid or a liquid. When the liquid containing the insect-controlling agent is a solution or a dispersion of the agent, the concentration of the agent in the liquid may be appropriately selected in accordance with the amount and shape of the resin article to be treated, the affinity between the agent and the resin article, the way of the contact between the liquid and the resin article, etc.

[0016] When the liquid containing the insect-controlling agent is an aqueous dispersion, it is preferable to add a spreading agent in order to improve the dispersibility of the insect-controlling agent. Examples of the spreading agent include anionic surfactants such as alkyl sulfate ester salt, alkyl sulfonate, alkyl aryl sulfonate, dialkyl sulfosuccinate, polyoxyethylene alkyl aryl ether phosphate, etc.; non-ionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, sorbitan fatty acid ester, polyoxyethylene fatty acid ester, etc.; glycerol fatty acid ester; lignin sulfonate; abietate; dinaphtylmethane disulfonate; and vegetable oils such as soybean oil, corn oil, cottonseed oil, sunflower oil, etc. Preferably, the spreading agent is added in an amount of from 100 to 1,000 mg per one L of the aqueous dispersion. [0017] When the article is brought into contact with the liquid containing the insect-controlling agent, the insect- controlling agent migrates into the resin constituting the article. The migration rate of the insect-controlling

agent into the article becomes larger as the temperatures of the article and the liquid become higher, and thus, the treatment can be done in a shorter time. When these temperatures are excessively high, the transpiration loss of the insect-controlling agent in use for the contact treatment becomes larger. Preferably, the temperatures of the article and the liquid are controlled to 50°C or lower, taking this matter into consideration, and are preferably room temperatures from the viewpoint of the working ease. [0018] The method to bring the article into contact with the liquid containing the insect-controlling agent is not limited. However, it is important that the contact between the resin article and the liquid containing the insect- controlling agent should be done so that a portion of the resin article to be intended to receive the insect- controlling agent can contact the liquid. For example, the resin article is immersed in a liquid containing a liquid insect-controlling agent or in a liquid dispersion which contains an insect-controlling agent and a liquid medium and which is being stirred; or a liquid containing an insect-controlling agent is sprayed onto the resin article. The amount of the liquid to contact the resin article may be appropriately selected in accordance with the concentration of the insect-controlling agent in the liquid, etc.

[0019] In one of preferred modes, the used insect- controlling resin article is washed and simultaneously is brought into contact with the liquid containing the insect- controlling agent to thereby carry the insect-controlling agent on the resin article. In this mode, the resin article is generally washed with water containing an

insect-controlling agent, and this water containing the insect-controlling agent is the above-described liquid containing the insect-controlling agent with which the resin article is brought into contact. Preferably, the water containing the insect-controlling agent further contains a detergent. The detergent usually contains a surfactant which can function as a spreading agent. [0020] After bringing the resin article into contact with the liquid containing the insect-controlling agent, an excess of the liquid may be removed from the surface of the resin article by suitable means. The liquid may be removed by wiping the article. When the liquid is a solution or a dispersion of the insect-controlling agent, the solvent or the dispersion medium may be distilled off. The distillation of the solvent or the dispersion medium may be done by heating in a drier, blowing a hot air or room temperature air, or air-drying outdoors or indoors. When the resin article is dried outdoor or indoors, it is preferable to dry the resin article in the shade, since the insect-controlling agent is likely to be decomposed by UV. [0021] The resin constituting the insect-controlling resin article to be treated by the method of the present invention is preferably a thermoplastic resin. Examples of the thermoplastic resin include vinyl monomer-polymerized resins such as polyolefin-based resins, acrylic resins and vinyl chloride resins; and condensation polymer resins such as polyester resins, polyamide resins and polycarbonate resins . [0022] The method of the present invention is preferably employed for articles of polyolefin-based resins. Examples of the polyolefin-based resins include homopolymers of α-

olefins and copolymers of different monomers which contain α-olefins as main components. Specific examples of the polyolefin-based resins include polyethylenes (e.g., low density polyethylenes, linear low density polyethylenes, medium density polyethylenes and high density polyethylenes) ; polypropylens; ethylene-α-olefin copolymers such as ethylene-propylene copolymers, ethylene-1-butene copolymers, ethylene-4-methyl-l-pentene copolymers, ethylene-1-hexene copolymers, ethylene-1-octene copolymers and ethylene-1-decene copolymers; copolymers of ethylene and polar vinyl monomers such as ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene- methyl methacrylate copolymers and ethylene-vinyl acetate- methyl methacrylate copolymers; and ionomer resins. [0023] It is preferable that the resin constituting the article contains a resin having a glass transition temperature of not higher than 10°C. Examples of the resin having a glass transition temperature of not higher than 10°C include polyethylene (e.g., low density polyethylene, linear low density polyethylene, medium density polyethylene and high density polyethylene) ; polypropylene; and polybutadiene . The addition amount of the resin having a glass transition temperature of not higher than 10°C is not limited, and it is preferably not smaller than 60%, more preferably not smaller than 80%. In the present invention, the glass transition temperature is measured according to JIS K7121.

[0024] The resin article may contain porous particles so as to easily carry the insect-controlling agent thereon. As the porous particles, silica particles can be used. The resin article containing the porous particles is brought

into contact with the above-described liquid containing the insect-controlling agent to thereby carry the insect- controlling agent on the porous particles. As a result, it becomes possible to bleed out the insect-controlling agent over a long period of time. The average particle size of the porous particles in the resin article is usually from 0.01 to 40 μm, more preferably from 0.03 to 20 μm. [0025] The insect-controlling resin article optionally may further contain an antioxidant, a UV absorber, a light resisting agent, an antistatic agent, a lubricant, an antiblocking agent, a pigment, a nucleating agent, a metal soap, etc., insofar as the insect-controlling function is not impaired. The resin article may further contain an active compound other than the insect-controlling agent, such as an antibacterial agent and a fungicidal agent.

[0026] The method of the present invention may use at least one insect-controlling agent. The insect-controlling agent referred to in the present invention is a generic name of agents which have insecticidal, insect proof, insect-repelling and insect growth-inhibiting functions.

Preferably, the insect-controlling agent contains an insect proof agent which is effective in vector control (controlling of a vector) . The vector control means getting rid of insects such as mosquitoes which carry protozoan and virus in order to prevent infectious diseases such as malaria and dengue fever.

[0027] The insect-controlling agent contains an agent which shows a vapor pressure of preferably not higher than 2 X 10 ^~5 mmHg at 25°C, more preferably not higher than 1 X 10 ^"6 mmHg at 25°C, from the viewpoint of effect persistence. [0028] Examples of the insect-controlling agent include

pyrethroid-based compounds, carbamate-based compounds, organophosphorus-based compounds, and neonicotinoid-based compounds, among which the pyrethroid-based compounds are preferred. Examples of the pyrethroid-based compounds include permethrin, cyphenothrin, d-phenothrin, 4- resmethrin, fenvalerate, fenpropathrin, etofenprox, tralomethrin, α-cypermethrin, λ-cyhalothrin, deltamethrin, metofluthrin, empenthrin, profluthrin, and transfluthrin. When two kinds or more of insect-controlling agents which are different in mechanism of action from each other are used in combination, insects which carry infectious diseases are hard to exhibit their resistance to the insect-controlling agents. [0029] As a synergist which enhances the effect of the insect-controlling agent, pyperonylbutoxide, N- octylbicyclo-heptenedicarboxyimide, N- (2-ethylhexyl) -1- isopropyl-4-methylbicyclo [2, 2, 2] oct-5-ene-2, 3- dicarboxyimide, octachlorodipropylether or the like may be further added. It is preferabe that the amount of the synergist be 0.1 to 3 times the amount of the insect- controlling agent.

[0030] The amount of the insect-controlling agent contained in the activated insect-controlling resin article is preferably from 0.1 to 10 g, more preferably not smaller than 0.5 g, still more preferably not smaller than 1 g, per 1 m ² of the surface area of the article. Again, the content of the insect-controlling agent contained in the activated insect-controlling resin article is preferably not larger than 10% by weight, more preferably not larger than 5% by weight.

[0031] The shape of the resin article is not limited.

The resin article may be in the shape of a sheet, film, strand, net, pellet or the like obtained by extrusion forming, or a lattice, three-dimensional structure or the like obtained by injection molding or blow molding. Preferable examples of the resin article are woven fabrics such as mosquito nets, and insect proof nets, obtained by weaving monofilaments or multifilaments spun from the resin, Articles constituted by filaments are generally high in contact efficiency relative to liquids, which leads to a higher insect-controlling agent-carrying efficiency.

Articles constituted by multifilaments are particularly preferable. The resin article may be of a single layer or of a multi-layer. It is preferable to coat the surfaces of the article with a resin which contains a resin having a glass transition temperature of not higher than 10 ⁰ C, from the viewpoint of the absorption of the insect-controlling agent.

[0032] EXAMPLES [0033] Hereinafter, the present invention will be described in more detail by way of Examples, which should not be construed as limiting the scope of the present invention in any way. The evaluations were conducted as follows. [0034] [Quantitative Analysis of

Insect-Controlling Agent]

A sample (about 2 g) was placed in a flat bottomed flask and was accurately weighed. After that, an internal standard solution (di-n-octyl phthalate (6,000 ppm) /xylene) (5 ml) was added, followed by further addition of xylene (45 ml). The resulting mixture was extracted at

75°C for 2 hours with a refluxing apparatus, and the extract was cooled and subjected to gas chromatography. Conditions for gas chromatographic analysis Detector: Hydrogen flame ionization detector Column: DB-17 capillary column Column temperature: 225°C Vaporization chamber temperature: 270°C Detector temperature: 280°C [0035] [Rate of Increase of Insect-Controlling Agent]

The weight (A g) of a resin article which had not yet been brought into contact with a liquid containing an insect-controlling agent, and the weight (B g) of the resin article which had been brought into contact with the liquid containing the insect-controlling agent and dried were measured. The increase of the insect-controlling agent (C (%)) was defined as follows: C (%) = (B - A) /A X 100. [0036] [Glass Transition Temperature (Tg) of Resin] The glass transition temperature (Tg) of the resin was measured according to JIS K7121. [0037] [Example 1]

A used mosquito net made of polyethylene (a contained insect-controlling agent: permethrin; the amount of the residual insect-controlling agent: 0.4% by weight; the initial content of the insect-controlling agent: 2% by weight; the size: 190 cm in width X 180 cm in length X 150 cm in height; the weight: 700 g; and Tg of polyethylene: - 125 ⁰ C) was stirred and washed in water (40 L) held in a washing machine to remove dirt from the mosquito net. The washed mosquito net was centrifugally dewatered and was then dried in a well ventilated shade outdoors. Next,

permethrin (25 g) and polyoxyethylene alkyl ether (25 g) were dispersed in water (40 L) in the above washing machine to prepare an aqueous dispersion. The dried mosquito net was immersed in the aqueous dispersion which was being stirred. The stirring was stopped after one hour had passed, and the mosquito net was still immersed in the dispersion for 24 hours. After that, the mosquito net was centrifugally dewatered and was further dried in a well ventilated shade outdoors. The weight of the mosquito net after dried was 709 g, and the increase of the insect- controlling agent was 1.3% by weight. [0038] [Example 2]

A neutral detergent for washing (25 g) and permethrin (25 g) were added to water (40 L) in the laundry sink of a washing machine, and the mixture was stirred to prepare an aqueous dispersion of permethrin. A used mosquito net made of polyethylene (a contained insect- controlling agent: permethrin; the amount of the residual insect-controlling agent: 0.4% by weight; the initial content of the insect-controlling agent: 2% by weight; the size: 190 cm in width X 180 cm in length X 150 cm in height; the weight: 700 g; and Tg of polyethylene: -125 ⁰ C) was immersed in the aqueous dispersion which was being stirred in the laundry sink. One hour later, the stirring was stopped, and the mosquito net was still immersed in the dispersion for 24 hours. After that, the mosquito net was centrifugally dewatered and was dried in a well ventilated shade. The weight of the mosquito net after dried was 707 g, and the increase of the insect-controlling agent was 1.0% by weight.

[0039] [Example 3]

A used insect proof net made of polyethylene (a contained insect-controlling agent: permethrin; the amount of the residual insect-controlling agent: 0% by weight; the initial content of the insect-controlling agent: 5% by weight; the size: 50 cm in width X 100 cm in length; the weight: 20 g; and Tg of polyethylene: -125°C) was washed with water to remove dirt from the insect proof net. The insect proof net was then dried in a well ventilated room. The insect proof net was immersed in liquid permethrin (1 L) in a container. The container was tightly sealed and left to stand at room temperature. After 24 hours had passed, the insect proof net was removed from the container, and the permethrin adhered to the surface of the insect proof net was washed and removed with ethanol. After that, the insect proof net was dried in a well ventilated room. The weight of the insect proof net after dried was 21 g, and the increase of the insect-controlling agent was 4.8% by weight. [0040] [Example 4] A used resin-made insect proof sheet (a contained insect-controlling agent: metofluthrin; the amount of the residual insect-controlling agent: 1% by weight; the initial content of the insect-controlling agent: 5% by weight; the resin: a mixed resin of a polyethylene (70% by weight) and an ethylene-methyl methacrylate (25% by weight) copolymer (30% by weight) ; Tg of polyethylene: -125°C; the weight: 50 g; and the thickness of the sheet: 0.05 mm) was washed with water to remove dirt from the insect proof sheet. The insect proof sheet was then dried in a well ventilated room. The insect proof sheet was immersed in liquid metofluthrin (1 L) in a container. The container

was tightly sealed and left to stand at room temperature. After 24 hours had passed, the insect proof sheet was removed from the container, and the metofluthrin adhered to the surface of the insect proof sheet was washed and removed with ethanol . After that, the insect proof sheet was dried in a well ventilated room. The weight of the insect proof sheet after dried was 53 g, and the increase of the insect-controlling agent was 6% by weight. [0041] [Example 5] A treatment was carried out in -the same manner as in Example 1, except that a used mosquito net made of polypropylene (a contained insect-controlling agent: permethrin; the amount of the residual insect-controlling agent: 0.2% by weight; the initial content of the insect- controlling agent: 2% by weight; the size: 190 cm in width X 180 cm in length X 150 cm in height; the weight: 700 g; and Tg of polypropylene: -10 ⁰ C) was used. The weight of the mosquito net after dried was 707 g, and the increase of the insect-controlling agent was 1% by weight. [0042] [Comparative Example]

A treatment was carried out in the same manner as in Example 1, except that the washed mosquito net was immersed in a dispersion prepared by dispersing polyoxyehtylene alkyl ether (25 g) alone in water (40 L) . The weight of the mosquito net after dried was 700 g, and thus, no increase in the weight was observed.