Title of Invention

AN EMANATOR

Abstract

An emanator(2) for emanating a composition into its surroundings, the emanator comprising: a container (4) for containing a volatile liquid comprising a composition to be emanated; an emanation surface (6) from which the volatile liquid evaporates; a wick (5) for transporting the volatile liquid from the container to the examination surface, characterized in that the transport of the liquid through both the wick and the emanator occurs at the surface of both the wick and the emanator and in that transport of the liquid through the wick occurs only at the surface of the wick. (Fig. 1)

Full Text

An Emanator Device This invention relates to a wick and émanation surface, and particularly, but not exclusively, to a wick and émanation surface for use in an insecticidal device or an air freshener. A particular type of insecticidal device or air freshener is known as an emanator. An emanator comprises a container in which a réservoir of volatile liquid is contained- The volatile liquid contains within it additives in the form of insecticidal compositions, if the device is an insecticidal device, or fragrance compositions, if the device is an air freshener. The device further comprises an émanation surface, from which the volatile liquid évaporâtes into its surroundings, and a wick extending from the réservoir to the émanation surface, for transporting the liquid from the réservoir to the émanation surface for evaporation. Evaporation of the liquid results in the fragrance or insecticidal compositions being released into the surroundings. For the sake of clarity the term air freshener will be used herein to refer to insecticidal devices as well as air fresheners, and the term fragrance composition will be used herein to refer to insecticidal compositions as well as fragrance compositions. Known wicks for use in emanators typically comprise a bundle of fibres loosely twisted, or a braided or woven cord, tape or tube, which draws up by capillary action the liquid in the réservoir and transports it to the émanation surface where it évaporâtes. Wicks may also be made from non-woven material, and porous polymer materials such as sintered plastics may also be used. A disadvantage of known emanators is that it is necessary to use a separate wick and émanation surface. This is because in order for a capillary action in a wick to effectively and efficiently draw up liquid from the reservoir to the emanating surface, it is necessary for a large void volume to exist within the capillary structure within the wick. Such a void structure does not, however, produce an efficient émanation surface, A further disadvantage is that the structure of one or both of thèse components will vary from pièce to pièce due to manufacturing processes, According to the first aspect of the présent invention there is provided an emanator for emanating a composition into its surroundings, the emanator comprising: a container for containing a volatile liquid comprising a composition to be emanated; an émanation surface from which the volatile liquid évaporâtes; a wick for transporting the volatile liquid from the container to the émanation surface, characterised in that the transport of the liquid through both the wick and the emanator occurs at the surface of both the wick and the emanator and in that transport of the liquid through the wick occurs only at the surface of the wick. According to a second aspect of the présent invention, there is provided an emanator for emanating a composition into the surroundinçs; the emanator comprising: a container for concaining a volatile liquid comprising a composition to be emanated; an émanation surface from which the volatile liquid évaporâtes; a wick for transporting the volatile liquid from the container to the émanation surface, characterised in that the wick and the émanation surface are integrally formed, and in that the wick transports the liquid from the container to the émanation surface only by means of capillary action at the surface-of the wick. The combined wick and émanation surface -will be referred to herein as the wicking and émanation system. By having the wick and the émanation surface integrally formed, the device is simpler and therefore cheaper to manufacture and assemble, and will allow improved consistency across and within the batch production. Advantageously, the wicking and émanation System is formed from a material formed with microgrooves. The term microgroove means a groove having a width measured in micrometers, or sub-micrometers. The grooves may hâve any suitable cross-sectional shape, such as semi-circular or rectangular, triangular or frusto-triangular in cross-section. A material formed with microgrooves may be described as being micro-structured or having a microstructure. tThe microgrooves act as capillaries, and are sub-divided or geometrically varied at the émanation surface to provids an extensive area for evaporation, The wicking and émanation System may be made from any material that is capable of being formed into microgrooves, but preferably the system is formed from a thermoplastics based material. A method of forming a microstructure is described in International patent application no. PCT/US99/01566 filed by Minnesota Mining and Manufacturing Company, ' • ■•» It is known from this patent application, that materials such as acrylates or urathane are suitable for forming an illuminating device, i.e. a light guide having one or more output portions arranged in such a fashion as to provide a desired pattern of illumination at a desired intensity. The materials are used to form a microstructure which in turn forms the illuminating device. The présent inventors hâve made the surprising discovery that a microstructure may be used as a wicking and émanation device in emanators of the type described herein. The materials described and discussed in WO 99/42270 would not be suitable for use as a combined wick/emanator. This is because materials such as acrylates and urathane would react with fragrances in the volatile liquid to be emanated and stress-cracking would occur. It is known in the field that fragrances or insecticidal actives tend to be particularly aggressive towards certain types of polymers. The fragrances or insecticidal actives are capable of reacting with thèse types of polymers and breaking down the molecular structures of the polymers causing stress cracking to occur. Suitable materials would therefore be ones which resist attack from the fragrances cr insecticidal actives such as polyolefins and PETG which stands for polyethyltetraphalateglycol. A whole range of materials are likely to be suitable for forming the microstructure. For the présent invention it is important to be able to choose a material which is chemically résistant to the fragrances to be used and has a relatively low cost. Preferably, the wick portion of the System comprises material having a microstructure in the form of substantially parallel grooves, each having a width in the range of 5 0 microns - 750 microns and positioned adjacent one another. It has been found that microgrooves having a diameter of 50 microns to 750 microns, subject to surface tensions and product viscosity, produce a material having oarticularly good capillary action. Advantageously, the émanation portion of the System comprises a microstructure comprising microgrooves which fan eut from the wicking microgrooves to form an émanation surface having a surface area to volume ratio that is large . For the émanation surface to perform effectively in the émanation of the liguid, it is necessary for there to be a large surface area to volume ratio in the range 5:1 to 100:1, The larger the surface area the higher the émanation rate by the process of surface air flow. The shallcwer the channels the more efficient the fragrance volume to fragrance release. There is of course a limit to the optimum ratio of surface area to volume, in that in an extrême situation, where there was virtually no depth of liquid, surface tension would hâve an adverse effect on the émanation of the liquid. Ideally the rate of wicking and émanation should be matched for optimisation. The particular size and geometry of the grooves will dépend upon the volatility of the fragrances used in the volatile liquid, however, for most applications, the release rate of the fragrance should be in the order of 0,1 cm3 to 10 cm3 per day, The size and geometry of the structure will therefore be calculated to resuit in a rate of release within this range. The emanator grooves are repositioned relative to the wicking grooves such that their depth is minimised and their surface area maximised within the constraints of fragrance transport. An advantage of using a microstructure to form the wicking and émanation system is that the transport of liquid is a surface transport and therefore absorption of the liquid into the system is minimal, if not non existent, thus improving evaporation efficiencies from the surface and reducing fragrance capture as experienced with absorption pads. The invention will now be further described by way of example only with référence to the accompanying drawings in which: Figure 1 is a schematic représentation of a wicking and émanation. System according to the présent invention; and Figure 2 is a schematic représentation of the wicking and emianation System cf figure i showing the microstructure of the System. Referring to Figure 1 a wicking and émanation System according to the présent invention is designated generally by the référence 1. The wicking and émanation system forms part of an emanator which may be used as an air freshener or insecticidal device. For the sake of clarity the présent example will be described in terms of an air freshener. The device incorporating the wicking and émanation System will be referred to by référence numéral (2). The emanator(2) comprises a liquid réservoir (3) -formed in a container (4). The wicking and émanation System (1), comprises a wicking portion (5) and an émanation System (6) . The wicking portion (5) has an end (7) remote from the émanation surface, which end is in contact with the liquid (3), Liquid from the liquid réservoir (3)is drawn up the wick portion (5) of the wicking and émanation system (1) by means of capillary action. When the liquid reaches the junction (8) between the wick portion (5) and the émanation surface (6) it is drawn into the émanation surface (6) also by capillary action to provide an extended surface area. Efficient evaporation can then occur from the émanation surface (6). The liquid contained in the réservoir (3) comprises a volatile liquid in which chemical additives hâve been added. The additives are in the form of fragrances which are released into the atmosphère when the liquid évaporâtes at the emanation surface. Referring now to figure (2) , the microstructure of the wicking and émanation system (1) is shown. The wicking portion (5) comprises a plurality of grooves (6) positioned adjacent one another. The cross-section of the grooves is frusto-triangular, although any other suitable shape could be used, Liquid from the réservoir (3) is drawn up the grooves (21) by capillary action towards the émanation surface (6). At the émanation surface each groove (21) divides into a plurality of grooves (23), in this case three grooves. For the sake of clarity the grooves forming the émanation surface (6) hâve been shown extending from one groove (21) only. Kowever, in reality similar structures would extend from each groove (21) providing an extended surface area from which the fragrance can evaporate. We claim - 1. An emanator (2) for emanating a composition into its surroundings, tine emanator comprising: a container (4) for containing a volatile liquid comprising a composition to be emanated; an emanation surface (6) from which the volatile liquid evaporates; a wick (6) for transporting the volatile liquid from the container to the emanation surface, wherein the transport of the liquid through both the wick and the emanator occurs at the surface of both the wick and the emanator and transport of the liquid through the wick occurs only at the surface of the wick, and the wicking and emanation system is formed from a material formed with microgrooves, characterized in that said microgrooves are sub-divided or geometrically varied at the emanation surface to provide an extensive surface for evaporation. 2. The emanator as claimed in claim 1 wherein the wick and the emanation surface are integrally formed, and the wick transports the liquid from the container to the emanation surface only by means of capillary action at the surface of the wick. 3. The emanator as claimed in claim 1 or claim 2 wherein the wicking and emanation system is formed from a polyolefin. 4. The emanator as claimed in any one of the preceding claims wherein the wick portion of the system comprises material having a microstructure in the form of substantially parallel grooves, each having a width in the range of 50 microns to 750 microns and positioned adjacent one another. 5. The emanator as claimed in any one of the preceding claims wherein the emanation portion of the system comprises a microstructure comprising microgrooves which fan out from the wicking microgrooves to form an emanation surface having a surface area to volume area that is large. 6. The emanator as claimed in any one of the preceding claims wherein the rate of wicking and emanation results in a release rate of 0.1 cm3 per day of the fragrance.

Documents:

0797-chenp-2003 abstract duplicate.pdf

0797-chenp-2003 claims duplicate.pdf

0797-chenp-2003 description (complete) duplicate.pdf

0797-chenp-2003 drawings duplicate.pdf

797-chenp-2003-abstract.pdf

797-chenp-2003-claims.pdf

797-chenp-2003-correspondnece-others.pdf

797-chenp-2003-correspondnece-po.pdf

797-chenp-2003-description(complete).pdf

797-chenp-2003-drawings.pdf

797-chenp-2003-form 1.pdf

797-chenp-2003-form 26.pdf

797-chenp-2003-form 3.pdf

797-chenp-2003-form 5.pdf

797-chenp-2003-other documents.pdf

797-chenp-2003-pct.pdf