WO2008012507A1

WO2008012507A1 - New insect control article for emanating pyrethroids

Info

Publication number: WO2008012507A1
Application number: PCT/GB2007/002719
Authority: WO
Inventors: Daniel Jeremy Craven; Boris Cvetko; Rod Nordsvan; Graeme Bruce Smith; Ian Andrew Thompson
Original assignee: Reckitt Benckiser (Australia) Pty Limited; Reckitt Benckiser (Uk) Limited
Priority date: 2006-07-24
Filing date: 2007-07-19
Publication date: 2008-01-31
Also published as: BRPI0714837A2; GB0614656D0; AU2007279075A1

Abstract

There is disclosed an insect control article comprising a foldable, foraminous web (1) impregnated with at least one vapour active pyrethroid; the web having an upper free edge and a lower edge attached to a base (2) which comprises a first and a second base portion; and a pivot means (6) intermediate the first and the second base portions, the pivot means being adapted to permit the article to adopt an open position in which the web is in an extended self-supporting fan-like shape which includes at least one fold and the at least one vapour active pyrethroid is permitted to emanate from the web at an insecticidally effective rate and a closed position in which the web is sandwiched between the first and the second base portions in a manner such that the at least one vapour active pyrethroid is limited in emanation from the web to a rate of less than 20% of the insecticidally effective rate.

Description

"New insect control article for emanating pyrethroids"

Field of the Invention

The present invention relates to a new insect control article for emanating pyrethroids in the control of flying insects, particularly mosquitoes.

Background of the Invention

The control of flying insects in an indoor or outdoor area has traditionally been controlled with the use of devices that dispense insecticide vapours into the atmosphere.

Devices that burn or heat a liquid or solid substrate to vaporise the active ingredient into the atmosphere require an energy source in the form of combustion, heating or electricity. Substrates such as coils impregnated with an active ingredient and citronella oil candles require burning to release the active while other substrates rely on electricity to heat the active so that it vaporises into the atmosphere. The release rates of active insecticides from continuous action products such as mosquito coils, candles, liquid vaporisers and electrically heated mats are essentially independent of the surrounding environment as the driving force for discharge of the active is supplied from within the system. The abovementioned articles and devices used to control mosquitoes have disadvantages. The combustion of mosquito coils requires a safe burning site and results in ash and smoke. The burning of a candle exposes a naked flame and therefore requires a safe burning site, while the use of electricity to heat an insecticidal device is costly in some developing countries and is not portable. There also exists ambient temperature moth repellent products that rely on passive evaporation of the insecticide from a substrate into the environment. These products, which have in the past been used to control moths, do not require an external source of energy, such as combustion, heat or electricity to release the insecticide into the atmosphere. Instead, an insecticide that vaporises at ambient temperature is required for these products. The concept of an ambient temperature moth repellent has many benefits: they provide long lasting and continuous protection; they are efficient in that there is no need for a means of heating; they are portable, modern and practical.

The above known ambient temperature products, however, also have disadvantages. Firstly, many of the prior art products are only effective in small, enclosed spaces and require significant air movement for the insecticide to be effective in a larger area of space. Secondly, there is a short falling in the number of cost- effective products that are able to work efficiently using low doses of insecticide for the control of insects other than moths, such as mosquitoes.

In attempting to address the above short comings, the present inventors have found ways for controlling insects, in particular mosquitoes, using a combination of substrate and a vapour active pyrethroid that allows passive emanation of the pyrethroid from the substrate at dose levels that achieve a minimum effective emanation rate and are cost effective.

Such products involving a substrate and a vapour active pyrethroid as developed by the present inventors, or indeed any of the above discussed known ambient temperature products, typically take the form of a flat substrate or a concertina-type arrangement having a number of honeycomb-like cells. The concertina-type arrangements are able to be expanded through 180° to 360° and be opened on a table to provide a bridge or fan configuration or closed into a circle to give a hanging lantern configuration or be hung to give a linear lantern configuration. There are, however, a number of disadvantages associated with such arrangements: In for instance the flat substrate arrangements, due to their flat configuration, the available surface area from which the active ingredient is able to emanate is small. As such, low rates of emanation to the atmosphere are observed. In the case of the bridge or fan configuration, many of the honeycomb- like cells are not fully expanded thereby leading to an inefficient use of available (or potential) surface area from which active ingredients are able to emanate. As such, lower rates of emanation to the atmosphere are observed. In the case of the hanging circular or linear configurations, these require some means of attachment, such as a hook, that will allow these to be hung to a wall or ceiling. Clearly, from a consumer point of view, having to attach a hook to a ceiling or a wall in order to allow the lantern to operate is undesirable.

Noting the disadvantages of the above arrangements, some of the present inventors found an improved device for retaining and emanating vapour active pyrethroids that is able to achieve improved rates of emanation. The device includes a holder and a substrate or matrix impregnated and/or dosed with the vapour active pyrethroid. The holder comprises a top, a base and a longitudinal member vertically extending from between the top and base, and the cellulosic based substrate or matrix adapted to be retained between the top and base and has a surface area so as to achieve sufficient emanation of the vapour active pyrethroid to control flying insects. Cellulosic based substrates/matrixes having a honeycomb configuration and multi- filament polyester or polyamide substrates/matrices were used. This device has disadvantages in that a separate holder device is required and the longitudinal member of the device renders it relatively bulky when in use and in storage. Further, the device has several components that need to be manufactured and requires relatively laborious assembling thereby adding cost and inconvenience to the user.

There exists a need for an improved insect control article that is portable, does not require the use of a separate holder device, is easy to manufacture and efficient in emanating insecticide when required, and able to be closed when not in use.

Disclosure of the Invention

The present inventors have developed an improved insect control article that is portable, easy to use, relatively inexpensive and easy to produce, and able to emanate an active ingredient at an insecticidally effective rate to control insects, particularly mosquitoes, when desired. In a first aspect, the present invention is directed to an insect control article comprising a foldable, foraminous web made of multifilament fibres having an air permeability of more than about 400 cm/s and being impregnated with at least one vapour active pyrethroid; the web having an upper free edge and a lower edge attached to a base which comprises a first base portion and a second base portion; and a pivot means intermediate the first and the second base portions, the pivot means being adapted to permit the article to adopt an open position in which the web is in an extended self-supporting fan-like shape which includes at least one fold and the at least one vapour active pyrethroid is permitted to emanate from the web at an insecticidally effective rate and a closed position in which the web is sandwiched between the first and the second base portions in a manner such that the at least one vapour active pyrethroid. is limited in emanation from the web to a rate of less than 20% of the insecticidally effective rate.

In a second aspect, the present invention is directed to an insect control article comprising a web impregnated with at least one vapour active pyrethroid; a base to support the web in a self-supporting fan-like shape; and means to pivot the insect control article between an open position and a closed position; such that when the insect control article is in the open position the web extends from one side of the base to another side of the base in a self-supporting fan-like shape and emanates the at least one vapour active pyrethroid at an insecticidally effective rate, the web being adapted to emanate the at least one vapour active pyrethroid at a rate of less than about 20% of the insecticidally effective rate when the insect control article is in the closed position and the web is in an unextended form; wherein the web i) is foraminous, ii) is made of mult i- filament fibre; iii) has an air permeability of greater than about 400cm/s; iv) has a porosity of greater than about 35%; and v) has the ability to retain at least one fold.

In a third aspect, the present invention is directed to a method of controlling flying insects comprising the steps of: providing an insect control article according to the first or second aspect of the invention; moving the support means into the second position and exposing the web to non augmented air flow; and allowing the vapour active pyrethroid to emanate from the web in to the air.

Detailed Description of the Invention Web foraminous

Throughout the specification the term "web" will be understood to mean a foraminous material. By foraminous material it will be understood that the material has foramina, is full of holes and/or is porous. The term holes will be understood to mean openings of any shape in or through the material. It will be appreciated that the formaninous material may result from holes being made in the material or by virtue of the way the material is manufactured. The foraminous material includes but is not limited to any material formed by weaving, interweaving or knitting fibres e.g. lace or crochet; a mesh of fibres to form a mesh material eg by knotting the intersections of the fibres to form meshes; a loosely-coherent sheet of fibres; fibres that are interlaced, tightly woven, or closely linked.

Preferably, the holes in the web have a hole size greater than about 0.05 mm², more preferably at about, or above, 0.5 mm².

The foraminous material of the web may be made of natural or synthetic fibres. Natural fibres include but are not limited to cellulosic material, cotton, silk and wool. Synthetic fibres include but are not limited to polyester or polyamide fibres. In one preferred embodiment, the web is formed from polyester or polyamide fibre. Preferably, the polyamide is nylon.

Fibres It will be appreciated that the fibres that make up the foraminous material may be composed of a number of filaments and hence be termed "multifilament". In a preferred embodiment, the web is made of multifilament polyester or polyamide fibres. In a preferred embodiment, the multifilament fibre has a filament count per thread greater than one, however counts of about 10-40 are preferred.

Preferably, the filaments that make up the fibre have a diameter of about 10-30 μm. The filaments may be circular, trilobal, hollow or any other suitable cross- sectional shape which, when bundled together form fibres suitable for knitting, weaving etc. In a preferred embodiment, polyester or polyamide filaments have a diameter of about 10-30 μm are used.

The present inventors have found that multifilament fibres provide for an increase in surface area from which the vapour active pyrethroid can emanate compared to material made of monofilament fibres due to an increased number of filaments present to construct the fibres. In a preferred embodiment, the web is made of multifilament polyester or polyamide fibre and it is the multifilament character of the multifilament polyester or polyamide fibre that enhances the wetting properties of the fibre and the ability of the fibre to retain or hold the vapour active pyrethroid.

Ease of wetting is an important aspect as it allows for the rapid distribution of the vapour active pyrethroid throughout the web simply by applying droplets of a solution containing the vapour active pyrethroid to the substrate and allowing it to spread by capillary action. Generally, multifilament polyesters or polyamides wet more easily than monofilament polyesters or polyamides and are therefore preferable in distributing a solution containing a vapour active pyrethroid throughout the web by capillary action. An associated advantage with the web being made of multifilament fibres, particularly multifilament polyester or polyamide fibres, is that vapour active pyrethroids will vapourise to a point where there is minimal residual substance remaining on the web. When a web made of multifilament polyester or polyamide fibres is dosed with, for example, vapour active pyrethroids in a carrier solvent, they evaporate to near completion.

From the above, it can be seen that the present inventors have recognised the importance of the ability of the web to hold an insecticidally effective amount of the vapour active pyrethroid and then emanate that amount of vapour active pyrethroid to near completion when the insect control article is in the open position and the web is exposed to air. This characteristic has been recognised as a preferred feature in providing an insect control article that is effective and economical to use and manufacture.

In accordance with preferred embodiments of the invention, the multifilament polyester or polyamide web is preferably a woven or knitted fabric. In the case of a woven multifilament web, any type of weave is suitable and may include plain, twill or satin weaves for example which have their usual meanings in the art. Alternatively, knitted fabrics may include both warp and weft knitting for example which have their usual meanings in the art. The multifilament polyester or polyamide (also referred to as a "polyester or polyamide thread" or " polyester or polyamide yarn") may be zero-twist, twisted or plaited or any other form suitable for weaving or knitting and may be manufactured from a continuous filament or from staple fibres.

In a preferred embodiment, the web is a multifilament knitted or woven web and more preferably, the multifilament web is in the form of a net or mesh. In a more preferred embodiment, the web is a mesh of knitted polyester multifilament fibres. According to § 303.7 Generic names and definitions for manufactured fibers from the Rules and Regulations under the United States Textile Fiber Products Identification Act 16 CFR Part 303, a "polyester" is defined as a manufactured fibre in which the fibre-forming substance is any long chain synthetic polymer composed of at least 85% by weight of an ester of a substituted aromatic carboxylic acid, including but not restricted to substituted terephthalate units and para substituted hydroxy-benzoate units. Persons skilled in the art, however, will appreciate that this is only one definition of the term "polyester" and other definitions are also encompassed by the invention.

In a preferred embodiment of the invention, the polyamide fibre is nylon. According to the Federal Trade Commission of the United States, "nylon" is defined as a manufactured fibre in which the fibre-forming substance is a long-chain synthetic polyamide having recurring amide groups as an integral part of the polymer chain. Persons skilled in the art, however, will appreciate that this is only one definition of the term "nylon" and other definitions are also encompassed by the invention.

As used herein, the term "net" encompasses any open fibre material made of knotting the intersections of the fibres to form meshes. Nets can be made in a variety of mesh sizes and weights matched to varying end uses.

As used herein, the term "knitted" material encompasses a method of constructing material by an interlocking series of loops of one or more fibres. The two major classes of knitting are warp knitting and weft knitting. In addition, as used herein, the term "knitted" material also encompasses any material in which the one or more filaments of a fibre pass through one another as they cross each other. This is opposed to a "woven" substrate wherein the one or more filaments of a fibre pass above and below one another as they cross each other.

Air permeability and Porosity The web has an air permeability (expressed in centimetres per second and measured according to Australian Standard AS 2001.2.34-90 (Determination of Permeability of Fabrics to Air) of more than about 400 cm/s, however material having an air permeability of more than about 444 cm/s are preferred.

The inventors have found that materials of the web having an air permeability of greater than 400 cm/s offer practically no resistance to air movement. The inventors have recognised that this level of air permeability is generally achieved by high levels _/ of porosity. Accordingly, the inventors have identified that the web preferably has a porosity (ratio of the void area contained within the boundaries of the fabric or material to the total area (solid matter and voids) expressed as a percentage) of more than about 35 %. Preferably, the web has a porosity of more than about 40%.

The present inventors have recognised that air permeability is an important characteristics in providing an insect control article that is effective and economical to use and manufacture.

Self supporting fan-like shape

The web is in a self-supporting fan-like shape when the insect control article is in the open position. Throughout the specification, reference to the web being in a fan- like shape will be synonymous with the web being in or existing in an "extended form". It will be appreciated that the web is in an unextended form or collapsed form when the insect control article is in the closed position. The extended form of the web is relative to the web in its unextended form. Accordingly, it will be understood that the extended form of the web may vary from fully extended to partially extended and reference to the insect control article being in the open position will incorporate all arrangements of the web from partially to fully extended Le wherein the arc or upper free edge of the fan extends or opens up to 360°. Whether the web is in a partially or fully extended form when the insect control article is in the open position will be dependent on whether the web emanates the vapour active pyrethroids at an insecticidally effective rate. It will be appreciated that when the web is in a fully extended form, there is a greater surface area of the web available for emanation of the vapour active pyrethroid in comparison to when the web is in its partially extended or unextended form. ) 8

Similarly, there is a greater surface area of web available for emanation of the vapour active pyrethroid in the partially extended form over the unextended form.

It will be appreciated that the word "fan-like shape" as used throughout the specification refers to a fan with at least one fold having an upper free edge and a lower edge that is attached to a base. Preferably, the fan-like shape of the web has one or more folds that are held together at one end with a hinge to form a hinged end of the web.

The fan-like shape is foldable in that when the insect control article is pivoted from the open to the closed position, the web folds to become sandwiched between the two portions of the base. In a preferred embodiment, the fan- like shape has a concertina type arrangement, i.e. the fan consists of a sheet of material folded sequentially in alternate directions to form a traditional fan that opens and closes in a concertina like fashion when the control article is pivoted between the open and closed positions. It will be appreciated that when the insect control article is in the open position, the fan- like shape of the web may be opened such that the web, more specifically the arc of the upper free edge of the web, extends or opens up to 360° provided that the vapour active pyrethroid emanates at an insecticidally effective rate. For instance, the fan-like shape of the web may be opened to about 90° and lent against a wall, or opened to about 180° and laid on a flat surface, or opened to about 360° into an arc or a circle and hung from the ceiling.

It will be appreciated that the extent to which the web will fully extend when the insect control article is in the open position will be dependent on the length of material used to make the fan. In this respect, it will be appreciated that the maximum arc of the upper free edge of the fan will be approximately equal to the length of the material used to make the fan prior to folding it into a fan-like arrangement.

According to the invention, the web has the characteristic of holding at least one fold.' The foraminous material of the web must be sufficiently rigid and/or stiff to hold at least one fold so that the web is self-supporting when the insect control article is in the open position and the web is in a fan-like shape.

Generally a stiffer material will hold a fold better than a material that is less stiff. The stiffness factor is important in providing a web that extends from one side of the base to the other to form a self-supporting fan-like shape. It will be understood that a material of less stiffness will provide a fan with "softer" folds than a material that is stiffer. Fans having "soft" folds are encompassed by the invention provided the web has the characteristic of being self-supporting when the control article is in the open position. It will be understood that a fan is not self-supporting if the fan does not hold its shape when the control article is in the open position but instead begins to flop or collapse. It will be appreciated that provided the web is self-supporting when the insect control article is in the open position and the web is in a fully extended form, then the insect control article may adopt an open position where the web is only partially extended or opened, i.e where the arc or upper free edge of the fan is not at its maximum.

In a preferred embodiment according to Figure 1, the web is in the form of a fan having a concertina type arrangement such that when the insect control article is in the open position, the base is opened out to approximately 180° to support the fan. In this embodiment, the base includes two approximately equal portions and the pivot means is a hinge (e.g. the heat sealed fabric of the web, a clip, sewn area etc) that holds together the ends of the fan. When the pivot means pivots the control article from the open to the closed position, the two portions of the base come together so that the webbing is in a collapsed, folded form and is sandwiched between each of the two portions of the base.

According to the invention, one or more insecticidally active substances emanates (i) at an insecticidally effective rate when the insect control article is in the open position; and (ii) at a rate of less than about 20% of the insecticidally effective rate when the insect control article is in the closed position. Accordingly, when emanation is required to control insects, the required surface area of the web can be exposed to the atmosphere and when emanation is not required or required to a lesser extent, then the pivot means allows the insect control article to pivot to the closed position or to a position where less surface area of the web is exposed to the atmosphere.

Preferably, the surface area of the web is in the range of 100 - 10,000 cm². The preferred surface area for indoor use of the insect control article of the invention is about 100 - 400 cm².

Preferably, the web has a grammage in the range of 25 - lOOgsm. The insect control article in the closed position emanates the at least one vapour active pyrethroids at a rate of less than about 20% of the insecticidally effective rate achieved when the insect control article is in the open position. Preferably, the insect control article in the closed position emanates the at least one vapour active pyrethroids at a rate of less than about 10%, more preferably less than about 5% and even more preferably less than about 1%. In the closed position, emanation of the at least one vapour active pyrethroids from the web will be at a minimum. In the closed position, the fan is folded into an unextended or collapsed form and is sandwiched between two portions of the base.

Base According to the present invention the insect control article has a base. The base is attached to the lower edge of the fan-like shape of the web and supports the web such that when the insect control article is in an open position the web emanates the one or more vapour active pyrethroids at an insecticidally effective rate and when the insect control article is in the closed position, the web is folded and sandwiched between the two portions of the base.

The base comprises a first base portion and a second base portion such that when then insect control article is in the closed position, the web is sandwiched between the first base portion and the second base portion. It will be understood that the base may consist of a plurality of base portions. Further, it will be understood that the base portions may be of varying size. The first and second base portions may be of equal size or different in size, preferably the first and second base portions are approximately equal in size.

In a preferred embodiment, the insect control article comprises a plurality of base portions and a plurality of pivot means, wherein when the insect control article is in the open position, two or more self supporting webs are separated by one or more base portions, and when the insect control article is in the closed position, the two or more webs are folded on top of one another with interposing base portions.

The base comprises one or more pieces of material such that the base may be in one piece or comprise two or more separate pieces. It will be appreciated that the one piece of the base may be formed by the joining of one or more base portions. Accordingly, the first base portion and second base portion may be on one piece of material or on separate pieces of material. In one preferred embodiment, the base is in one piece and the first base portion and second base portion are separated by the means to pivot, e.g. one or more fold lines, such that the first and second base portions are approximately equal in size. In another preferred embodiment, the base consists of two pieces of material of approximately equal size, one piece being the first base portion and the other piece being the second base portion. The two pieces may be directly attached to one another by way of the pivot means. Alternatively, the two pieces may be separate but kept in close proximity to one another when the insect control article is in the open position by way of the pivot means hinging the folded ends of the web to form the fan-like shape. Preferably, when the insect control article is in the open position, the gap between the two pieces of the base is large enough to accommodate the means to pivot, more preferably, the gap is as small as possible. This is to ensure that when the insect control article is in the closed position, the first and second base portions completely covers the folded web from the atmosphere to achieve minimal emanation (< about 20%) of the vapour active pyrethroid from the insect control article.

The base may include one or more flaps. It will be understood that a flap projects from the base and includes at least two walls. The walls may be joined by any known means including but not limited to a fold line and/or a hinge, as hereinafter described. It will be appreciated that the walls of the flap do not need to be the same size. Preferably, the walls of the flap are approximately the same size. The one or more flaps may be formed by one or more folds in the base or by bringing and optionally joining two portions of the base together. Preferably, the folded ends of the fan- like shape of the web are sandwiched between the two walls of the flap. It will be appreciated that the walls of the flap and the folded ends of the fan like-shape of the web may all be of varying size. In a preferred embodiment the folded ends of the fan- like shape of the web are hinged, as hereinafter described, to form a hinged end of the web such that the hinged end of the web is sandwiched between the two walls of the flap. Preferably the flap is centrally located along the base.

In one preferred embodiment according to Figure 2, the base is in one piece and the flap is formed by two outer folds about a central fold wherein the two outer folds are in the opposite direction to the central fold. Preferably, the two outer fold lines are symmetrical about the central fold line. The two outer folds are brought together to form a flap having two walls. Preferably, the folded ends of the fan are sandwiched between the walls of the flap. In a preferred embodiment, the folded ends of the fan sandwiched between the two walls of the flap are hinged, preferably welded, together. It will be appreciated that the folded ends of the fan may or may not be hinged prior to being sandwiched, between the walls of the flap and hinged together.

As is discussed below, the pivot means may include one or more folds in the base. It will be appreciated that the one or more folds may form the one or more flaps. In a preferred embodiment, the flap is formed from three folds in the base such that the flap comprises two walls joined by a central fold and two outer folds. In this embodiment, the two outer folds of the flap function as a means to pivot. This is discussed in more detail below.

When the insect control article is in the closed position, the web is in a folded, unextended or collapsed form and is sandwiched between the first and second base portions. In effect, when the insect control article is in the closed position, the first and second base portions form a protective cover over the outer surface of the folded web. The closed position is therefore important for preventing loss of the vapour active pyrethroid from the web.

It will be appreciated that the base may be adjusted to any position and that this will depend on where the insect control article is placed and the amount of insect control required. The base may fold so that the angle between the first and second base portions is up to about 360°. For instance, when the insect control article is placed on a flat surface, the base will open so that the first base portion lies at an angle of approximately 180° to the second base portion, alternatively the base may be folded, so that the first base portion lies at about 90° to the second base portion, enabling it to lean against a wall. In a preferred embodiment when the insect control article is in the open position on a flat surface, the base is relatively flat and opened to approximately 180°. It will be appreciated that the angle made by the relative position of the first and second base portions will be reflected by the angle of the arc of the upper free edge of the web. The base may be made of any material capable of attaching and supporting the web when the insect control article is in the open position and the web is a fan in an extended form. Preferably, the base is formed of a material that holds its shape and which prevents migration and/or absorption of the one or more vapour active pyrethroids. Alternatively, the insect control article comprises a coated or lined base in which the coating or lining is formed of a material which prevents migration and/or absorption of the one or more vapour active pyrethroids into the base. It will be appreciated that the base may be formed of one or more different materials.

The material of the base includes but is not limited to plastic, cardboard, coated cardboard, laminated paper, metal, wood and coated wood. It will be appreciated that the coated cardboard and coated wood include but are not limited to foil coated cardboard, foil coated wood, plastic coated cardboard, plastic coated wood, resin coated cardboard and resin coated wood. Preferably, the base is made of plastic.

The web may be attached to the base according to any known method. Similarly, the two or more portions of the base may be attached to one another according to any known means. Examples of attachment include but are not limited to one or more of the following: gluing, clipping, heat sealing (including but not limited to RF (radio frequency) welding, ultrasonic welding, impact welding etc), over-moulding, laminating, stapling, interference fit, hinging and bayonets. As indicated above, it will be appreciated that the two or more portions of the base need not be attached to one another. In one embodiment, the base includes one or more flat sheets of plastic. More preferably, the base includes two sheets of plastic of approximately equal size.

In another embodiment, the base includes one or more shallow thermoformed trays. More preferably, the base includes two shallow thermoformed trays of approximately equal size.

Preferably, when the insect control article is in the closed position, the fan is folded into an unextended form and sandwiched between two approximately equal portions of the folded base. In one preferred embodiment, the two portions of the folded base are held close together when the insect control article is in the closed position to ensure that there is minimal emanation of the vapour active insecticide from the sides of the folded web. The two portions of the base may be held together with one or more known fasteners including but not limited to lugs or any other interference fitting mechanism which interlocks to keep the device closed when not in use.

Pivot means

The control article of the present invention comprises a means to pivot the insect control article between an open and a closed position. Throughout the specification, the phrase "pivot means" and "means to pivot" will be used interchangably. The pivot means is intermediate the first and second base portions. It will be understood that the pivot means is located at one or more positions between the first and second base portions when the insect control article is the open and/or closed position. The pivot means may be integral with the base or separate to the base. By integral it will be understood that the pivot means is incorporated into the base. In embodiments where the pivot means is integral with the base, it will be appreciated that the pivot means may lie anywhere along the base between the first base portion and the second base portion.

In embodiments where the pivot means is separate to the base, such as when the pivot means is the hinged ends of the fan- like shape of the web, it will be appreciated that when the insect control article is in the open position such that the first base portion is 180° to the second base portion, the pivot means may lie slightly above the plane of the first and second base portions. In the closed position, the pivot means would lie between the first and second base portions.

In a preferred embodiment, the pivot means lies between the first base portion and the second base portion which are of approximately equal size. It will be understood that the pivot means does not hold a memory for the closed position to ensure that the insect control article stays in the open position. The pivot means includes but is not limited to one or more of the following: one or more fold lines in the base that allows the insect control article to fold between the closed and open position, a hinge that connects two or more separate portions of the base together so that one portion can move relative to the other, a hinge that holds together the ends of the web so that the web forms a fan when the insect control article is in the open position. Hinge has been defined below.

Preferably, the pivot means includes a hinge that holds together the ends of the folded fan, either on its own or in combination with one or more folds in the base or a hinge that connects the first and second base portions.

When the base is made from one piece of material, it will be understood that the pivot means includes one or more fold lines on the base. When more than one fold line is present, the base may be folded, preferably into a flap as previously described, and secured so as to accommodate, hold and hinge the ends of the fan. It will be appreciated that the pivot means may include the fold lines on the base that form the flap. Preferably, the pivot means includes two fold lines on the base, wherein the two fold lines form the flap. In a preferred embodiment, the folded ends of the fan-like shape of the web are sandwiched between the walls of the flap and secured such that the ends of the fan are effectively hinged. It will be appreciated that the flap may be secured by way of a hinge as defined herein. Accordingly, in a preferred embodiment the pivot means may also include the flap as a hinge.

In a preferred embodiment according to Figure 2, the base includes a flap formed from three folds in the base. The flap comprises two walls joined by a central fold and two outer folds. In this embodiment, the two outer folds of the flap and the flap securing the folded ends of the fan, function as the means to pivot. In an alternate embodiment, the flap may be formed by two separate portions of the base each folding at two separate fold lines such that the two separate portions of the base come together to form a flap with two walls. In this alternate embodiment, the two fold lines on the base and the flap securing the folded ends of the fan, function as the means to pivot. It will be understood that the fold lines may be formed by weakening the base at the desired area using known techniques which will depend on the material of the base. It will be appreciated that the one or more fold lines may be formed by folding and applying pressure, by heat treating, slitting or scoring the area to weaken the area to be folded, or by any other known technique used to enable the selected material to fold. Preferably the material of the base is plastic and accordingly any known technique used to enable plastic to fold may be used.

The hinge may be made of flexible material, or of moving components and includes but is not limited to clips, sticky tape, glue, heat sealed material (including RF welding, ultrasonic welding, impact welding etc), the material of the web, over- moulding, laminating, stapling, sewing, interference fit, metal hinge, bayonets etc

In one preferred embodiment according to. Figure 1 in which the base is in one piece, the means to pivot is a combination of the hinged ends of the folded fan (eg by heat sealing, clipping, sewing, gluing or taping) with a fold in the base, to form the first and second base portions.

In another preferred embodiment, the first and second base portions are two separate pieces of material and the sole means to pivot is the hinged end of the fan.

In yet another preferred embodiment according to Figure 2 in which the base is in one piece, the pivot means includes two fold lines and a hinge in the form of a flap. In this preferred embodiment, the base is folded at three points, one central fold and two outer folds on either side of the central fold, to form a central flap. Preferably, the two outer folds are equidistant from the central fold.

The flap is formed when the two outer fold lines are folded in one direction and brought together and the central fold line is folded in the opposite direction. In this preferred embodiment, the ends of the fan-like shape of the web are sandwiched between the walls of the flap so that the flap acts as a hinge for the ends of the fan- like shaped web. It will be appreciated that the ends of the fan may already be hinged prior to being inserted into the flap. The flap and the ends of fan may be held together by known means including but not limited to clips, glue, heat sealing, and stapling. As noted above, the insect control article of the present invention may include more than one pivot means in conjunction with more than two base portions. In one preferred embodiment, multiple base portions may be used in conjunction with multiple pivot means. Accordingly, in such an embodiment, when the insect control article is in the open position, two or more self supporting webs containing one or more pivot means may separated by one or more base portions.

Impregnated and dosed

According to the present invention, the web is impregnated with at least one vapour active pyrethroid. It will be understood that the web is impregnated with at least one vapour active pyrethroid when the pyrethroid is either partially or completely distributed between the fibres of the substrate in such a manner that the substance fills all or some of the interstices of the substrate and is directly held within the substrate and supported thereby, but is largely not absorbed within the individual fibres. It will be understood that when a specific quantity of the pyrethroid is applied to the web and either partially or completely impregnates the web as described above the web is deemed to be "dosed" with the vapour active pyrethroid.

As stated earlier, the present inventors have identified the characteristic that the web of the control article of the. present invention has the ability to hold a specific amount of the at least one vapour active pyrethroid and then emanate that specific amount of vapour active pyrethroid to near completion once the web is exposed to air. It will be appreciated that this occurs once the web has been impregnated/dosed with the vapour active pyrethorid.

Vapour active pyrethroids

It will be understood that vapour active pyrethroids are those that vaporise at ambient temperature (ie. about 15-4O⁰C) without heat or combustion. The at least one vapour active pyrethroids are preferably selected from the group consisting of metofluthrin (1.9 mPa/ 25°C), transfluthrin (0.40 mPa/20°C), empenthrin (14 mPa/23.6°C), methothrin, tefiuthrin (8.4 mPa/20°C,), and fenfluthrin (1.0 mPa/20°C), or combinations thereof. The vapour pressures of these compounds are given in parentheses. It will be appreciated that one or more vapour active pyrethroids may be employed in the present invention. Preferably, the vapour active pyrethroid is metofluthrin. Metofluthrin has high potency against mosquitoes, flies, and moths. The chemical name of metofluthrin is 2,3,5,6-tetrafluro-4-(methoxymethyl)benzyl-(EZ)- (lRS,3RS;lRS,3SR)-2,2-dimethyl-3-(prop-l-enyl)cyclopropanecarboxylate. Metofluthrin is available from the Sumitomo Chemical Company.

The web has the ability to hold an insecticidally effective amount of the at least one vapour active pyrethroid and then emanate that specific amount to near completion at an insecticidally effective rate when the insect control article is in the open position and the web is exposed to air. An insecticidally effective amount, will be understood to mean the amount of vapour active pyrethroid required to be impregnated into the web to result in emanation of the vapour active pyrethroid from the web in an amount that is insecticidally effective for a specified period of time.

Preferably, the web is impregnated with one or more vapour active pyrethroids in an amount of approximately 10 - 10,000 mg/m , more preferably 100 - 5,000 mg/m , even more preferably 500 - 2,500 mg/m². In one preferred embodiment the web is impregnated with 750 mg/m² for a 14 night product. The emanation or release of the vapour active pyrethroids from the web into the surrounding environment may be referred to as the emanation rate or release rate and will be understood to mean the depletion of an amount of vapour active pyrethroids from the fibres of the web over a certain period of time and has a unit of measurement ofmg/h. The emanation rate is a measure of efficacy in controlling flying insects. The inventors have found that, apart from environmental factors such as temperature and airflow, the emanation rate is primarily affected by the air permeability and porosity of the fibres of the material making up the web for any given surface area. The amount of the vapour active pyrethroid coated and/or dosed onto the web will determine the duration of the emanation of the pyrethroid.

The present inventors have found that emanation of a vapour active pyrethroid, preferably metofluthrin, from the web into the atmosphere at a rate of at least about 0.040 mg/h, more preferably at least about 0.075 mg/h, is required to effectively control flying insects, particularly mosquitoes and moths at a temperature in the range of about 15-40°C, more preferably, 21-35⁰C. Throughout the specification, the emanation rate of about 0.040 mg/h may be referred to as the minimum effective emanation rate (MEER). This MEER may be achieved by controlling a variety of parameters including but not limited to the material of the web; the available emanation surface area and the folding of the web; temperature, and air flow. The possibility of achieving emanation of the vapour active pyrethroid from the web according to the present invention at low temperatures in the range of about 15-21°C contributes to the commercial viability of the various aspects of the invention.

According to the invention, when the insect control article is in the open position the web emanates the at least one or more vapour active pyrethroids at an insecticidally effective rate. It will be understood that an insecticidally effective rate is the emanation rate required to control the insects in the atmosphere when the insect control article is in use. Accordingly, it will be understood that the insecticidally effective rate will at least be equal to the MEER.

When the insect control article is in an open position, the web is a self supported fan and air flow passes through the web to emanate the one or more vapour active pyrethroids at an insecticidally effective rate. Preferably, non-augmented air flow passes through the web. It will be understood that an environment with non-augmented air movement refers to natural air movement that passes over and/or through the web, thereby allowing the vapour active insecticide to passively emanate into the atmosphere. It excludes the use of mechanical fans, heat and other mechanical means of increasing air movement. Suitable environments include but are not limited to enclosed rooms and open volumes of space, such as patios and the like, with air movement provided by natural causes such as breeze entering through windows or people moving around in a room. It will be appreciated that while a mechanical fan is not necessary for emanation of the vapour active pyrethroid from the insect control article of the present invention, in the presence of a mechanical fan an increased emanation rate will be observed.

Throughout the specification, the term "passive emanation" is used to describe the process by which the vapour active pyrethroid emanates from the web into the atmosphere without the obligate application of external energy. As noted above, the emanation rate of the vapour active pyrethroid from the web is affected by a number of parameters, apart from environmental factors such as temperature and airflow, including, air permeability and porosity. This in turn means that products effective in killing and/or repelling insects over different time periods, such as for 8 h and 300 h, may be different. Some air movement is required in order for the pyrethroid to emanate from the web into the atmosphere. The rate of emanation increases with increased air flow. A minimal air flow, such as the movement of people or open windows and/or doors, is sufficient to allow a minimum emanation rate of about 0.040 mg/h, and the preferred emanation rate of about 0.075 mg/h. The vapour active pyrethroid may be applied to the web by any method known to persons skilled in the art, for example, a solution of the pyrethroid could be applied by droplets, spraying or dipping.

Carrier solvent According to the invention, the web is impregnated with the at least one vapour active pyrethroid, preferably metofluthrin. Preferably, the vapour active pyrethroid is dissolved in a carrier solvent. The carrier solvent may be any solvent or combination of solvents in which the vapour active pyrethroid is soluble.

The inventors have identified two important physical properties of solvents that may be used to characterise and classify preferred carrier solvents. The first is the boiling point and the second is the evaporation rate according to the ASTM (American

Society for Testing and Materials) D3539-87 (Standard Test Methods for Evaporation

Rates of Volatile Liquids by Shell Thin-Film Evaporometer).

Preferably, the carrier solvent has a boiling point in the range between about 33- 285°C, more preferably, about 50-265°C. The carrier solvent may be selected from, but not limited to, chlorinated hydrocarbons (e.g. 1,1,1-trichloroethane, dichloromethane, chloroform); alcohols (e.g. methanol, ethanol, n-propanol); ketones (e.g. acetone); alcohol and ketone mixtures (e.g. acetone/ethanol (1:1 by volume)); normal paraffins with a boiling point range of about 155-276°C (e.g. Norpar 12); dearomatised aliphatic hydrocarbons and their blends in the boiling point range of about 33-265⁰C (e.g. pentane, heptane, hexane, Exxsol D40, Exxsol D80 and Exxsol DlOO); isoparaffins in the boiling point range of about 150-285°C (e.g. Isopar G, and Isopar M); glycol ethers in the boiling point range of about 120-243°C; natural or synthetically derived aroma chemicals as discussed above. The Norpar, Exxsol and Isopar solvents are all available from Mobil Exxon.

The inventors have found that the use of low boiling point solvents with high evaporation rates will be effective as carrier solvents. The inventors have also found that the use of higher boiling point solvents with lower evaporation rates leads to a preferred embodiment of the invention. In a preferred embodiment, the web is impregnated with the vapour active pyrethroid, preferably metofluthrin in a carrier solvent.

In this embodiment, the vapour active pyrethroid, preferably metofluthrin, is dissolved in the carrier solvent and the resulting solution is applied to the web such that the vapour active pyrethroid is distributed, preferably evenly, throughout the web. The carrier solvent used is preferably a solvent that does not evaporate within about 10 minutes after application onto the web and more preferably is characterised by having a high boiling point and a low evaporation rate. However, the evaporation rate of the carrier solvent is required to be faster than that of the vapour active pyrethroid.

Preferably, the carrier solvent has a boiling point in the range of about 120- 285°C, more preferably about 150-265°C, and may be selected from known solvents including but not limited to normal paraffins with a boiling point range of about 155- 276°C, such as Norpar 12; dearomatised aliphatic hydrocarbons and their blends in the boiling point range of about 150 -265°C such as Exxsol D40, Exxsol D80 and Exxsol DlOO; isoparaffins in the boiling point range of about 150-285°C such as Isopar G and Isopar M and glycol ethers in the boiling point range of about 120-243°C.

In a preferred embodiment, the carrier solvent used has an evaporation rate according to ASTM D3539-87 of less than about 1.0, a boiling point in the range of about 120-285⁰C, preferably about 150-265°C.

It will be understood that solvents used for applying a vapour active pyrethroid to the web may be employed as carrier solvents in all aspects of the present invention that require a carrier solvent. While the use of carrier solvents is discussed with particular reference to vapour active pyrethroids, it will be understood that the use of carrier solvents as described above is contemplated in connection with the application of any vapour active substance to the multifilament polyester or polyamide fibre substrate web requiring the presence of a carrier solvent.

Insect control

The insect control devices of the present invention are used in one embodiment to control flying insects. The flying insects may be selected from but not limited to biting Dipterous pests (Order Diptera) such as mosquitoes (Family Culicidae), biting midges (Family Ceratopogonidae), black flies (Family Simulidae), sandflies (certain Psychodidae) and biting flies (various families eg Muscidae and Tabanidae) and non- biting Dipterous insects (e.g. flies and midges of various families including, but not limited to Muscidae, Calliphoridae, Drosophilidae, Chironomidae and Psychodidae) and certain moths (Order Lepidoptera). Preferably, the insect control devices of the present invention are used to control mosquitoes.

It will be understood that "control" of the flying insect population includes but is not limited to any one of or a combination of killing, repelling (bite inhibition) or knocking down a flying insect. It will be appreciated that a typical way of measuring the performance of an insecticide is in the form of "knockdown" or by using "bite inhibition" studies.

Indicator

In a preferred embodiment of the invention, the insect control article also comprises an end of life (EOL) indicator to enable a user to ascertain when the insect control article is depleted of the vapour active pyrethroid. Any known indicator may be used, preferably the indicator disclosed in JP602240603 is used on the control article of the present invention.

Preferably, the EOL includes the use of one or more fragrances with the vapour active pyrethroid and optionally the carrier solvent.

The EOL is preferably attached to one end of the base and does not come in contact with the web when the control article is in the open or closed position.

In order to understand better the nature of the invention, a number of Preferred embodiments and Examples will now be described.

Brief Description of the Figures Figure 1 shows a perspective view of an insect control article in accordance with a preferred embodiment of the invention. The open (Figure Ia) and closed (Figure Ib) positions are shown.

Figure 2a shows a perspective view an insect control article in accordance with a preferred embodiment of the invention. The open (Figure Ia) and closed (Figure Ib) positions are shown.

Figure 2c shows a plan view of the base of the insect control article of a Figure 2a prior to it being folded and prior to attachment of the web to the base.

Figure 2d shows the A-A sectional view of the three fold lines on the base in Figure 2c folded to form a flap.

Figure 2e shows the B-B sectional view of the three fold lines on the base in Figure 2a folded to form a flap that accommodates the folded ends of the fan-like shape of the web.

Detailed Description of the Invention

Referring to Figure 1, an insect control article according to a preferred embodiment of the invention is shown. Throughout the specification this article will be referred to as the "fan" article. The fan article comprises a web (1), base (2), means to pivot the insect control article between a closed (Figure Ib) and open (Figure Ia) position in the form of hinge (6) and fold line (4). The web (1) is shown as a foraminous material in the form of a net. The web (1) is impregnated with one or more vapour active pyrethroids.

It can be seen that the web (1) adopts a fan- like shape in the form of a concertina like arrangement, such that when the insect control article is in the open position (Figure Ia), the web is in a concertina fan form, and when in the closed position (Figure Ib), the web is folded like a closed fan and sandwiched between the two halves of the base (2). It will be appreciated that the web opens and closes in a concertina like fashion when the control article pivots between the open and closed positions. The web is made of a material that is sufficiently rigid and/or stiff to hold at least one fold and enables the web to be a self supporting fan when the insect control article is in the open position. It will be appreciated that base (2) provides a foundation for the web to stand on and to be attached while web (1) has a rigidity or stiffness that strengthens and holds the web in the form of a fan. When the insect control article is in its open position, the base (2) and the material of the web support the web (1) in an extended form in a fan-like shape such that air flow, preferably non-augmented air flow, is able to pass over and/or through the web to emanate the one or more vapour active pyrethroids at an insecticidally effective rate. In this open position, the web (1) extends from one side of the base (2) to the other side of the base (2) in the form of a fan. The web (1) is supported in an extended form when the outer ends of the fan are attached to the base and the material of the web is made of sufficiently rigid and/or stiff material to hold the folds of the fan when open.

In another embodiment, the insect control article may further comprise one or more outwardly extending members secured to the means to pivot and extending outwardly from the base between the folds of the web to provide a point of attachment if hanging of the insect control article is desired.

The means to pivot the insect control article between an open and closed position is in the form of a fold line (4) and hinge (6). It will be appreciated that the fold line (4) may be formed by simply folding the base (2) in half and applying pressure along the folded area to create a fold line (4). It will be understood that the fold line (4) may be formed by weakening the base at the desired area using known techniques which will depend on the material of the base. Preferably, the base is made of plastic and accordingly, the fold line (4) may be formed by slitting to weaken the area to be folded or any other known technique used to enable plastic to fold.

The hinge (6) holds together the ends of the folded fan. It will be appreciated that the hinge (6) may be in the form of glue, clips, a heat sealed seam of the ends of the fan or any other known hinge. In a preferred embodiment, the web is made of multifilament polyester and the hinge (6) is a seam formed by heat sealing or sewing one end of the fan.

^• The fold line (4) and the hinge (6) pivot the insect control article between the open (Figure Ia) and closed (Figure Ib) positions. To pivot the support means from the open position (Figure Ia) to the closed position (Figure Ib) the base is folded in half at the fold line (4) in a direction that allows the web to collapse into an unextended form and wherein the web folds so as to be sandwiched between each of the halves of the base (2). It will be appreciated that the base (2) may be in two sections such that the hinge

(6) becomes the sole means to pivot the insect control article between the first and second position. In this preferred embodiment, the two sections of the base are long enough to support the outer fold of the of the fan and provide a gap for the hinge (6).

According to the invention, the web is adapted to emanate the at least one vapour active pyrethroid at a rate of less than 20 % when the insect control article is in the closed position (Figure Ib) and the web is in an unextended or folded form. It can be seen from Figure Ib, that when the insect control article is in the closed position that the web is in an unextended, folded form and held between the outer two flaps formed from the two halves of the base (2).

When the insect control article is in the closed position (Figure Ib) the control article is in a relatively flat, portable form.

Referring to Figure 2, an insect control article according to another preferred embodiment of the invention is shown. This article will also be referred to as the "fan" article. The fan article in this embodiment comprises a web (1), base (2), means to pivot the insect control article between a closed (Figure 2b) and open (Figure 2a) position in the form of hinge (6), flap (10) and fold lines (7) and (8). The web (1) is shown as a foraminous material in the form of a net. The web (1) is impregnated with one or more vapour active pyrethroids.

It can be seen that the web (1) adopts a fan- like shape in the form of a concertina like arrangement, such that when the insect control article is in the open position (Figure 2a), the web is in a concertina fan form, and when in the closed position (Figure 2b), the web is folded like a closed fan and sandwiched between the two halves of the base (2).

When the insect control article is in its open position, the web (1) extends from one side of the base (2) to the other side of the base (2) in the form of a fan. The web (1) is supported in an extended form when the outer ends of the fan are attached to the base and the material of the web is made of sufficiently rigid and/or stiff material to hold the folds of the fan when open.

The means to pivot the insect control article between an open and closed position is in the form of hinge (6), flap (10) and fold lines (7) and (8). Figure 2c shows a plan view of the base of the insect control article prior to it being folded and prior to attachment of the web to the base. It can be seen that the base is in one piece and that three fold lines (7), (8) and (9) are required in the base to enable it to adopt the configuration of the base in the insect control article of Figure 2a. Figure 2c shows a central fold line (9) and two fold lines (7) and (8) on either side of the central fold line (9).

It will be appreciated that the fold lines (7), (8) and (9) may be formed by simply folding the base (2) in the area to be folded and applying pressure. It will be understood that the fold lines (7), (8) and (9) may be formed by weakening the base at the desired area using known techniques which will depend on the material of the base. Preferably, the base is made of plastic and accordingly, the fold lines (7), (8) and (9) may be formed by slitting to weaken the area to be folded or any other known technique used to enable plastic to fold.

Figure 2d shows the configuration of the base once it has been folded but prior to attachment of the web to form the control article according to Figure 2a. As is shown in Figure 2d, the base is folded at fold lines (7), (8) and (9) to form a central flap (10). The flap (10) is formed when the two outer fold lines (7) and (8) are folded in one direction and brought together and the central fold line (9) is folded in the opposite direction. It can be seen that flap (10) includes two walls (10a) and (10b).

Figure 2e shows in detail the folded base (1) and how it sandwiches the folded ends of the fan-like shape of the web. In this preferred embodiment, the ends of the fan- like shape of the web are sandwiched between the two walls of the flap (10). The flap (10) acts as a hinge for the ends of the fan-like shaped web. The two walls of the flap and the sandwiched ends of the fan- like shape of the web may be secured together by way of a hinge, as defined below. The hinge (6) holds together the ends of the folded fan. It will be appreciated that the hinge may be in the form of glue, clips, a heat sealed seam of the ends of the fan or any other known hinge. In a preferred embodiment, the web is made of multifilament polyester and the hinge (6) is a seam formed by heat sealing or sewing one end of the fan. It will be appreciated, however, that the ends of the fan need not be hinged prior to being secured between the flap.

The ends of fan sandwiched between the two walls of the flap (10) may be hinged together by known means including but not limited to clips, glue, heat sealing, and stapling. In a preferred embodiment, the base and hence the flap (10), is made of plastic and the web is a multifilament polyester. Accordingly, the ends of the fan-like shape of the web are preferably secured by way of heat treatment to the two walls of the flap.

From Figures 2a, 2d and 2e, it can be seen that the pivot means includes the two fold lines (7) and (8) and a hinge in the form of a flap (10).

The two fold lines (7) and (8) and the hinge in the form of flap (10) pivot the insect control article between the open (Figure 2a) and closed (Figure 2b) positions. To pivot the support means from the open position (Figure 2a) to the closed position (Figure 2b) the base is folded at the fold lines (7) and (8) in a direction that allows the web (1) to collapse into an unext ended form and wherein the web folds so as to be sandwiched between each of the halves of the base (2). According to the invention, the web is adapted to emanate the at least one vapour active pyrethroid at a rate of less than 20 % when the insect control article is in the closed position (Figure 2b) and the web is in an unextended or folded form. It can be seen from Figure Ib, that when the insect control article is in the closed position that the web is in an unextended, folded form and held between the outer two flaps formed from the two halves of the base (2). When the insect control article is in the closed position (Figure 2b) the control article is in a relatively flat, portable form.

Examples

Example 1 -Bioefficacy example

In this example, the mosquito bite inhibition properties of a metofluthrin-treated multi- filament woven polyester fabric fan insect control device according to the present invention was compared to a metofluthrin-treated paper honeycomb device. The device according to the invention was fabricated according to the fan design using a multi- filament woven polyester fabric netting of 400 cm² surface area. A commercially available 18gsm paper honeycomb (ReckittBenckiser Pakistan) was used for comparison. The polyester device was dosed with metofiuthrin according to the following table, the metofiuthrin being previously dissolved in 0.8 ml of a normal paraffin solvent (boiling range 189 - 218⁰C). The devices were, in turn, placed in the centre of a 40 m³ purpose built, test chamber, the chamber being maintained at a temperature range of 28.3-31.5⁰C and a relative humidity range of 25-42%.

After 15 minutes had elapsed, approximately 150 mixed sex Aedes aegypti mosquitoes were introduced into the test chamber. An assessment of bite inhibition was conducted, commencing 1 minute after the mosquito release. In this assessment a human forearm was introduced into the chamber via a vent in the wall of the chamber. The number of mosquitoes landing and attempting to bite were counted over a 2-minute period and the procedure was repeated using a second vent and second arm so as to give a total exposure of 4 minutes during the assessment time. Assessments were conducted between 1-6 minutes, 7-12 minutes, 20-35 minutes after mosquitoes were introduced into the chamber. The number of mosquitoes visible on the floor of the chamber was counted at each time period as a measure of knockdown.

This procedure was repeated to give a total of three (3) replicates per test formulation, an untreated control being also conducted in order to establish mosquito bite density. Percent mosquito repellency and knockdown for the respective treatments was then calculated against the untreated control.

Table 1

As can be seen from Table 1, good bite inhibition results are observed for the polyester fan, a preferred embodiment of the present invention It can be seen that the polyester fan according to the present invention works as well as the much larger surface area paper honeycomb device.

Example 2 - Field trial

In this example, the ability of the fan insect control article according to the invention to reduce biting by mosquitoes in homes under tropical conditions was investigated. A multi-filament woven polyester fabric fan according to the present invention with a web surface area of 400 cm² dosed with 35 mg metofiuthrin was compared to a commercially available 0.005% metofiuthrin mosquito coil (Reckitt Benckiser Indonesia) and a commercially available 18gsm paper metofiuthrin treated honeycomb (Reckitt Benckiser Pakistan)!

Trials were conducted in homes in a village in SE Asia with high levels of mosquito activity. Rooms had open windows and doors and averaged 56 m³ in volume. Mosquito biting behaviour was assessed over 6 hours per night by collecting mosquitoes as they attempted to bite bare legs. 99% of mosquitoes collected were identified as Culex quinquefasciatus. % reduction in biting was calculated by comparing average bite numbers on nights before treatment with that measured during treatment nights in both treated and untreated rooms according to the following formula. Treatments were replicated 12 times. % Reduction = 100 - (C₁ X T₂) X 100^'

(T₁ X C₂)

Ci:No of mosquitoes collected in 'control' rooms throughout pretreatment night C₂:No of mosquitoes collected in "control' rooms throughout treatment night TiiNo of mosquitoes collected in "treated' rooms throughout pretreatment night T₂:No of mosquitoes collected in 'treated' rooms throughout treatment night

The results are summarised in the Table 2 below

Table 2

Once again it can be seen that the polyester fan according to the present invention works as well as the much larger surface area paper honeycomb device. Both the paper honeycomb and the polyester web device were highly effective at reducing mosquito numbers in comparison to a mosquito coil.

Claims

CLAIMS:

1. An insect control article comprising a foldable, foraminous web made of multifilament fibres having an air permeability of more than about 400 cm/s and being impregnated with at least one vapour active pyrethroid; the web having an upper free edge and a lower edge attached to a base which comprises a first base portion and a second base portion; and a pivot means intermediate the first and the second base portions, the pivot means being adapted to permit the article to adopt an open position in which the web is in an extended self-supporting fan-like shape which includes at least one fold and the at least one vapour active pyrethroid is permitted to emanate from the web at an insecticidally effective rate and a closed position in which the web is sandwiched between the first and the second base portions in a manner such that the at least one vapour active pyrethroid is limited in emanation from the web to a rate of less than 20% of the insecticidally effective rate.

2. An insect control article comprising a web impregnated with at least one vapour active pyrethroid; a base to support the web in a self supporting fan-like shape; and means to pivot the insect control article between an open position and a closed position; such that when the insect control article is in the open position the web extends from one side of the base to another side of the base in a self supporting fan-like shape and emanates the at least one vapour active pyrethroid at an insecticidally effective rate, the web being adapted to emanate the at least one vapour active pyrethroid at a rate of below about 20% of the insecticidally effective rate when the insect control article is in the closed position and the web is in an unextended form; wherein the web i) is foraminous, ii) is made of multi-filament fibre; iii) has an air permeability of greater than about 400cm/s; iv) has a porosity of greater than about 35%; and v) has the ability to retain at least one fold.

3. The insect control article according to either of claims 1 or 2 wherein the web is foraminous and has a hole size greater than about 0.05 mm², preferably at about or above 0.5 mm².

4. The insect control article according to any one of claims 1 - 3, wherein the web has an air permeability of more than about 444 cm/s.

5. The insect control article according to any one of claims 1-4 wherein the web is made of natural or synthetic fibres.

6. The insect control article according to any one of claims 1-5 wherein the web is made of multifilament polyester or polyamide fibres.

7. The insect control article according to any one of claims 1-6 wherein the multifilament fibre has a filament count per thread greater than 1, preferably of about 10-40.

8. The insect control article according to any one of claims 1-7 wherein the web is made up of multifilament fibres having filaments with a diameter of about 10-30 μm.

9 The insect control article according to any one of claims 1-8 wherein the web has a porosity of more than about 35%, preferably of more than about 40%.

10. The insect control article according to any one of claims 1-9, wherein the web is a mesh of knitted polyester multifilament fibres.

11. The insect control article according to any one of claims 1-10 wherein the insect control article in the closed position emanates the at least one vapour active pyrethroid at a rate of less than about 10%, preferably below about 5% and more preferably below about 1% of the insecticidally effective rate.

12. The insect control article according to any one of claims 1 - 11, wherein the at least one vapour active pyrethroid is selected from any one of metofluthrin, transfluthrin, empenthrin, methothrin, tefluthrin or fenfluthrin or combinations thereof.

13. The insect control article according to any one of claims 1 - 12, wherein the vapour active pyrethroid is dissolved in a carrier solvent.

14. The insect control article according to any one of claims 1 - 13, wherein the carrier solvent has an evaporation rate according to ASTM D3539-87 of less than about

1.0 and a boiling point in the range of about 120-300⁰C, preferably the carrier solvent is selected from the group consisting of normal paraffins with a boiling point range of about 155-276°C; dearomatised aliphatic hydrocarbons and their blends in the boiling point range of about 150 -265°; isoparaffins in the boiling point range of about 150- 285°C; and glycol ethers in the boiling point range of about 120-243⁰C.

15. The insect control article according to any one of claims 1 - 14, wherein the insect control article in the open position, emanates the at least one vapour active insecticide at the insecticidally effective rate of at least 0.040 mg/h, preferably at least 0.075 mg/h.

16. The insect control article according to any one of claims 1 - 15 for controlling flying insects, preferably mosquitoes.

17. The insect control article according to any one of claims 1-16 wherein the fan has a concertina type arrangement.

18. The insect control article according to any one of claims 1-17 wherein the base is in one piece.

19. The insect control article according to any one of claims 1-17, wherein the base comprises two pieces, preferably of approximately equal lengths.

20. The insect control article according to any one of claims 1-19 wherein the base is formed of a material which prevents migration or absorption of the one or more vapour active pyrethroids.

21. The insect control article according to any one of claims 1-19 comprising a coated or lined base in which the coating or lining is formed of a material which prevents migration or absorption of the one or more vapour active pyrethroids into the base.

22. The insect control article according to any one of claims 1-20 wherein the base is formed of one or more of the following materials: plastic, cardboard, coated cardboard, laminated paper, metal, wood and coated wood.

23. The insect control article according to claim 22 wherein the coated cardboard comprises one of: foil coated cardboard, plastic coated cardboard or resin coated cardboard.

24. The insect control article according to any one of claims 1-22 wherein the base is plastic.

25. The insect control article according to any one of claims 1-22 or claim 24 wherein the base includes two shallow thermoformed plastic trays of approximately equal size.

26. The insect control article according to claim 25 wherein when the insect control article is in the closed position, the two plastic trays are held together with one or more fasteners.

27. The insect control article according to any one of claims 1-26 wherein the pivot means is selected from one or more of the following: one or more fold lines in the base, one or more weakened areas on the base, and one or more hinges.

28. The insect control article according to claim 27 wherein the base includes a first base portion and a second base portion and the pivot means is a hinge that connects the first base portion and the second base portion.

29. The insect control article according to claim 27 wherein the base includes a first base portion and a second base portion and the pivot means includes one or more fold lines.

30. The insect control article according to claim 27 or 29 wherein the pivot means includes one fold line that divides the base into a first base portion and a second base portion of approximately equal size.

31. The insect control article according to any one of claims 27, 29 or 30 wherein the fan-like shape of the web includes one or more folds that are held together at a one end with a hinge to form a hinged end of the web; and the base includes a flap having two walls; the flap being located in the centre of the base with the hinged end of the web being sandwiched between the two walls of the flap.

32. The insect control article according to claim 31 wherein the hinged end of the web and the two walls of the flap are welded together by way of heat treatment.

33. The insect control article according to any one of claims 1-32 wherein the fan- like shape of the web has one or more folds that are held together at one end by a hinge.

34. The insect control article according to any one of claims 28, 30-33 wherein the hinge is selected from one or more of the following: clips, sticky tape, glue, heat sealed material, the material of the web, thread, over-moulding, laminating, stapling, interference fit, metal hinge and bayonets.

35. The insect control article according to claim 34, wherein the web is a multifilament polyester and the hinge is a heat sealed section of the multifilament polyester web.

36. The insect control article according to claim 27 wherein the weakened area on the base is formed by heat treatment, slitting and/or scoring.

37. The insect control article according to any one of claims 1-36 wherein the insect control article further comprises an end of life (EOL) indicator.

38. A method of controlling flying insects comprising the steps of: providing an insect control article according to any one of claims 1-37; moving the support means into the second position; exposing the web to non augmented air flow; and allowing the vapour active pyrethroid to emanate from the web in to the air.