BE1030394A1 - DELIVERY DEVICE FOR VOLATILE SUBSTANCES - Google Patents

Abstract

The present invention relates to a dispensing device containing a reservoir; a liquid volatile material therein; a heating device; a wick designed to deliver the volatile material from the reservoir to a heated location within the heater to promote the release of vaporized volatile material from the wick; wherein the liquid volatile material comprises carnosol, carnosic acid, a salt thereof or a mixture thereof. The invention relates to a kit and reservoir suitable for said dispensing device. The invention further relates to a method for delivering a volatile material from a dispensing device.

Description

1 BE2022/5220

DELIVERY DEVICE FOR VOLATILE SUBSTANCES

FIELD OF INVENTION

This invention relates to volatile substance delivery devices that use active agents to release volatile substances from a substrate impregnated with volatile substances.

BACKGROUND

Devices for releasing thermally or otherwise volatilizable materials into the atmosphere are well known. Such volatilizable materials may include air odorants (e.g., fragrances), pest control materials (e.g., insecticides), allergen control ingredients, disinfectants, and the like.

In one type of volatile material dispensing device, a heat source is used to promote capillary action and the release of a volatile material from a wick, one end of which is immersed in a volatile liquid contained in a reservoir located. One version of this type of device plugs into a wall outlet to provide power to a heating coil in an enclosure. The heat generated increases the temperature of a material in the wick and volatilizes the material.

Convection air currents spread the volatilized material into the room.

Examples of this type of device and related devices can be found in U.S. Patent Nos. 6,361,752; 5,647,053; 5,290,546; 5,222,186; 5,095,647; 5,038,394; and 4,663,315; and European Patent No. EP 1 825 748. The description of these patents and all other publications referred to herein are incorporated herein by reference as if fully set forth.

In another type of volatile material delivery device, a rigid, porous mat (usually made of a pressed, cellulosic, fibrous material) is impregnated with a volatile material, or a volatile material is placed in a pan-like metal structure. These mats and pans are then placed on heaters to evaporate the volatile material into the atmosphere. Examples of this type of device and related devices can be found in U.S. Patent Nos. 6,446,384; 6,309,986; 6,031,967; 5,945,094; and 4,391,781.

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In yet another type of volatile material dispensing device, a rigid, porous mat is impregnated with a volatile material, and the mat is held within the device so that a stream of hot gases from a fuel burner passes over the mat and causes the volatile material evaporates into the atmosphere. An example of this type of device can be found in PCT International Patent Publication Number WO 00/78835.

In yet another type of volatile material dispensing device, moving air is directed against a substrate or through a reticulated or otherwise airflow-permeable substrate to thereby volatilize volatile material with which the substrate is impregnated. Examples of this type of device can be found in

U.S. Patent No. 5,547,616 and in PCT International Patent Publication No. WO 01/02025.

While all of these devices provide satisfactory results under certain conditions, there are disadvantages to each type of device.

In devices that use a heat source to promote the release of a volatile material from a wick immersed in a volatile liquid composed of solvents and dissolved active ingredients, currently available capillary action materials limit device performance. For example, when porous wicks made of felt or cloth are used in such a device, there is a tendency as the wick is heated for the solvents to volatilize rapidly, so the solvents quickly volatilize, leaving high boiling point materials in the wick .

The high boiling point materials remaining in the wick can cause clogging of the wick. Other wick materials include ceramic and compressed sawdust. However, these wicks experience the same type of clogging when used in a device that uses a heat source to promote the release of a volatile material from a wick immersed in a volatile liquid. As a result, it is difficult to maintain stable evaporation of the volatile liquid for extended periods of time. Although the uniform release of volatiles has been reported in US Patent No. 4,286,754 for non-heated blades, the problem of non-linear release in heated blades remains.

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Certain volatile materials, such as some insecticide formulations, contain materials that are either or become non-volatile when the liquid is heated in a wick. These non-volatile materials can cause wick clogging, leading to a less uniform volatile release rate during use over time and high residual levels of non-volatile materials in a spent wick. For example, pyrethrum insecticides typically include or form non-volatile waxes or polymers. When used in a dispensing device with conventional ceramic or sawdust wick, these waxes form sludges that can clog the wick. Ceramic and sawdust wick systems therefore do not allow effective use of insecticidal formulas containing natural pyrethrins and terpenes.

One proposed solution to the problems associated with wick clogging by nonvolatile substances formed by oxidation of pyrethrum insecticides is the use of antioxidants in the liquid formulation. See, for example, U.S. Patent No. 4,968,487 which specifically uses BHT and

BHA. However, despite antioxidants, some cross-linking of the isoprene units in liquid insecticide formulations occurs, forming non-volatile components that reduce the capillary action of traditional wicks. The performance losses in these systems can be attributed to clogging of the small pores and the effects of the high tortuosity (twists and turns) in conventional blade materials.

Thus, there is a need for an improved liquid delivery wick that can be used in a dispensing device that uses a heat source or other active means to promote the release of a volatile material from the wick. In particular, there is a need for wicks that provide improved efficacy (including but not limited to non-clogging, linear and complete volatile release) and low cost, along with compatibility with existing delivery devices.

SUMMARY OF THE INVENTION

The present invention and embodiments thereof serve to provide a solution for one or more of the above-mentioned disadvantages. To this end the present invention relates to a dispensing device according to claim 1.

Preferred embodiments of the device are shown in one of claims 2-7.

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A specific preferred embodiment relates to an invention according to claim 3. The combination of pyrethrins and carnosic acid has shown a linear evaporation rate during the life of the wick. Furthermore, both pyrethrins and carnosic acid may be of natural origin. This is advantageous compared to synthetic derivatives of (natural) pyrethrum. It is also desired by an increasing number of consumers who prefer 'green' alternatives or alternatives of natural origin, due to concerns regarding ecological impact and safety.

In a second aspect, the present invention relates to a kit according to claim 8.

In a third aspect, the present invention relates to a reservoir according to claim 12.

In a fourth aspect, the present invention relates to a method for dispensing a volatile material according to claim 14. The inventors discovered that the evaporation rate remained surprisingly constant over the life of the wick compared to the prior art.

The invention further relates to a method in which the dispensing device is activated less frequently according to claim 11. The inventors surprisingly discovered that the volatile substances were released at an insect control rate even when the heating device was activated only 9 hours per day. In the prior art, heating devices are generally activated 12 hours per day. Without being bound by theory, it is believed that prior art dispensers use longer heating times to ensure that volatiles are released at an insect control rate when the wick has a significant build-up of solid residue.

To ensure that volatile substances are released at an insect control rate, even when the evaporation rate decreases, prior art dispensing devices are activated for longer or more intensively. With a more constant evaporation rate, the activation time, without increasing the intensity, while ensuring volatilization with an insect control rate. This in turn also increases the life of the wick, as clogging usually occurs when the heater is activated.

DESCRIPTION OF THE FIGURES

The following description of the figures of specific embodiments of the invention is exemplary only in nature and is not intended to limit the present teachings, their application or use. In all drawings, corresponding reference numerals indicate similar or corresponding parts and features.

Figure 1A is a perspective view showing a device for dispensing volatile materials from a wick embodying the invention.

Figure 1B is a cross-sectional side view of the device of Figure 1A.

Figure 2A is a perspective view showing another device for dispensing volatile materials from a wick embodying the invention.

Figure 2B is a cross-sectional side view of the device of Figure 2A.

Figure 3A shows a wick after 396 hours of heating with a liquid volatile material according to the present invention.

Figure 3B shows a wick after 350 hours of heating with a liquid volatile material according to the prior art.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a dispensing device, a kit suitable for constructing the dispensing device, a reservoir suitable for such a dispensing device and a method for dispensing a volatile material.

Unless otherwise defined, all terms used in the description of the invention, including technical and scientific terms, have the meanings commonly understood by one of ordinary skill in the art to which this invention pertains. As further guidance, term definitions are included to better appreciate the teachings of the present invention.

As used herein, the following terms have the following meanings: “A,” “the,” and “it,” as used herein, refer to both singular and plural referents unless the context clearly indicates otherwise. By way of example, 'a compartment' refers to one or more compartments.

6 BE2022/5220 'Approximately' as used herein, referring to a measurable value such as a parameter, a quantity, a period of time and the like, is intended to indicate variations of +/- 20% or less, preferably +/- 10% or less more preferably +/- 5% or less, even more preferably +/- 1% or less, and even more preferably +/- 0.1% or less of and from the specified value, to the extent that such variations are suitable to be made in the disclosed invention. However, it should be understood that the value to which the modifier 'about' refers is itself specifically revealed. "Include", "comprising" and "includes" and "consisting of" as used herein are synonymous with "containing", "containing" or "containing", "entailing", "involving", "entailing" and are inclusive or open terms that specify the presence of what follows (e.g., a component) and do not exclude the presence of additional, unnamed components, features, elements, parts, steps, which are well known in the art or described therein out.

Furthermore, the terms 'first', 'second', 'third' and the like are used in the description and in the claims to distinguish similar elements and not necessarily to describe a sequence, either temporal or spatial, unless otherwise stated. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operating in any order other than that described or shown herein.

Quoting numerical ranges by endpoints includes all numbers and fractions included within that range, as well as the quoted endpoints.

The expression '% wt', 'wt %', '%wt' or 'wt%', here and throughout the description, unless otherwise defined, refers to the relative weight of the respective component based on the total weight of the wording.

While the terms "one or more" or "at least one", such as one or more or at least one member(s) of a group of members, is self-evident, by further explanation the term includes, among other things, a reference to one of the members, or to two or more of the members, such as for example any >3, 24, 25, 26 or >7 etc. of the members, and to all mentioned members.

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Unless otherwise defined, all terms used in the description of the invention, including technical and scientific terms, have the meanings commonly understood by one of ordinary skill in the art to which this invention pertains. As further guidance, definitions for terms used in the description are included to better appreciate the teachings of the present invention. The terms or definitions used herein are intended solely to assist in the understanding of the invention.

Reference throughout this specification to “one embodiment” or “an embodiment” means that a specific feature, structure or feature described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, occurrences of the phrases "in one embodiment" or "in an embodiment" at various places throughout this specification do not necessarily all refer to the same embodiment, but may do so. Furthermore, the specific features, structures or characteristics may be combined in any suitable manner, as would be apparent to one skilled in the art based on this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some, but not other, features included in other embodiments, combinations of features of different embodiments are intended to be within the scope of the invention, and constitute different embodiments, as would be understood by those skilled in the art . For example, in the following claims, any of the claimed embodiments can be used in any combination.

An “effective amount” or “effective release rate” and similar term is defined as that amount or rate sufficient to achieve the intended effect. 'Active agent(s)' is defined as heat, moving air or other means to impart energy to a volatile material to be delivered, and a volatile material delivery device that uses active agents to deliver volatile material shall are referred to as the 'active release' of the volatile substances.

To be effective, volatile active ingredients for insect control must be delivered at not less than an “insect control rate,” defined herein as that rate sufficient to repel or otherwise control target insects within the space to be protected.

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In a first aspect, the invention provides a dispensing device with a reservoir (28); a liquid volatile material (34) in a reservoir (28); a heating device (25); a wick (31) designed to deliver the volatile material (34) from the reservoir (28) to a heated location within the heater (25) to promote the release of vaporized volatile material from the wick (31); wherein the volatile material (34) in the reservoir comprises an insect control active ingredient; and the wick (31) comprises a substrate of particles or fibers bonded together to form a body with a network of pores and passageways, the inner surfaces of which are non-reactive and non-absorbent with respect to the volatile material (34 ) to be delivered, the body being shaped to occupy the heated location in the heater (25), activation of the volatile release device releasing the volatile material from the pores, which volatile material is then released when the heating device (25) is activated, wherein the liquid volatile material comprises carnosol, carnosic acid, a salt thereof or a mixture thereof.

The inventors discovered that the addition of carnosol, carnosic acid, a salt thereof or a mixture thereof significantly reduced the build-up of solid residue in the wick. The aged wick looks clean and retains the same diameter even after 45 days of use.

When solid residue accumulates within a wick, the diameter of the wick increases. This leads to difficulties in removing the heater wick and/or reservoir, which are usually tight. Increasing the tolerance between the wick and the reservoir and/or heater is not desirable due to the increased, uncontrolled evaporation of the volatiles associated with convection. In addition, the build-up of solid residue tends to exacerbate the build-up of material stress within the blade; which makes the blade more brittle.

By reducing the build-up of solid residue in wick, the wick does not become thicker or brittle and can be easily removed from both the heater and the reservoir. This makes reuse of the heating device considerably easier and more pleasant for the consumer.

New wicks and volatile material reservoirs can be supplied and attached to a reusable heating device. In a lake

9 BE2022/5220 preferred embodiment, wicks can also be reused and attached to a new reservoir containing fresh volatile material.

In a preferred embodiment, the sum of the concentration of carnosol, carnosic acid and salts thereof is between 0.001 and 0.1% by weight relative to the liquid volatile material. The inventors have found that this concentration range is sufficient to prevent the build-up of solid residue in the wick.

In a preferred embodiment, the insect control material is pyrethrins, more preferably natural pyrethrins. 'Natural' pyrethrins as described herein come from plants, preferably flowers. The term 'pyrethroids' refers to insecticides related to pyrethrins that do not occur in nature and can only be produced synthetically.

In a preferred embodiment, carnosol, carnosic acid, a salt thereof or a mixture thereof is derived from rosemary extract. Rosemary as described herein refers to Rosmarinus officinalis.

In a particularly advantageous embodiment, pyrethrins as well as carnosol, carnosic acid, a salt thereof or a mixture thereof are of natural origin.

These 'green' alternatives are ecologically desirable and are generally perceived as desirable by customers and consumers. In a preferred embodiment, the rosemary extract is odorless. The delivery device of the present invention is aimed at providing insecticidal activity; not to give a desired scent. Some consumers prefer that the dispensing device operates odorless.

In a preferred embodiment, the liquid volatile material comprises pyrethrins, preferably natural pyrethrins, in an amount of at least 0.1% by weight relative to the liquid volatile material, preferably in an amount of at least 0.5% by weight, more preferably in an amount of at least 1.0% by weight, more preferably in an amount of at least 2.0% by weight, more preferably in an amount of at least 2.5% by weight, with more preferably in an amount of at least 3.0% by weight, more preferably in an amount of at least 3.5% by weight, more preferably in an amount of at least 4.0% by weight, more preferably in an amount of at least 4.5% by weight, most preferably in an amount of about 5.0% by weight. In

BE2022/5220 a preferred embodiment, the liquid volatile material comprises pyrethrins, preferably natural pyrethrins, in an amount of a maximum of 25% by weight with respect to the weight of the liquid volatile material, more preferably in an amount of a maximum of 20% by weight. , more preferably in an amount of up to 15% by weight, more preferably in an amount of up to 14% by weight, more preferably in an amount of up to 13% by weight, more preferably in an amount of up to 12% by weight .%, more preferably in an amount of up to 11 wt.%, more preferably in an amount of up to 10 wt.%, more preferably in an amount of up to 9 wt.%, more preferably in an amount of up to 8% by weight, more preferably in an amount of up to 7.5% by weight, more preferably in an amount of up to 7.0% by weight, more preferably in an amount of up to 6.5% by weight, more preferably in an amount of up to 6.0% by weight, more preferably in an amount of up to 5.5% by weight, more preferably in an amount of about 5.0% by weight. In a preferred embodiment, the liquid volatile material comprises pyrethrins, preferably natural pyrethrins, in an amount of 1.0 to 15.0% by weight relative to the weight of the volatile material, more preferably in an amount of 1.0 to 10.0% by weight, more preferably in an amount of 2.0 to 8.0% by weight, more preferably in an amount of 2.5 to 7.5% by weight, more preferably in an amount of 3.0 to 7.0% by weight.

In a further preferred embodiment the liquid volatile material comprises 1.0 to 10.0 wt% rosemary extract, preferably the liquid volatile material comprises 1.5 to 9.5 wt% rosemary extract, preferably the liquid volatile material comprises 2.0 up to 9.0% by weight rosemary extract, preferably the liquid volatile material comprises 2.5 to 8.5% by weight rosemary extract, preferably the liquid volatile material comprises 3.0 to 8.0% by weight rosemary extract, preferably comprises the liquid volatile material comprises 4.0 to 8.0 wt% rosemary extract, preferably the liquid volatile material comprises 5.0 to 8.0 wt% rosemary extract, most preferably the liquid volatile material comprises 5.5 to 7, 5% by weight rosemary extract.

In a preferred embodiment, the ratio of rosemary extract to pyrethrins, preferably natural pyrethrins, in the volatile liquid material is at least 1:100, preferably at least 1:50, more preferably at least 1:40, more preferably at least 1 :30, more preferably at least 1:20, more preferably at least 1:15, most preferably about 1:10.

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In a preferred embodiment, the ratio of rosemary extract to pyrethrins, preferably natural pyrethrins, in the volatile liquid material is at most 5:1, more preferably at most 1:1, more preferably at most 1:2, more preferably at most 1:4, more preferably at most 1:5, more preferably at most 1:8, most preferably about 1:10. In a preferred embodiment, the ratio of rosemary extract to pyrethrins, preferably natural pyrethrins, in the volatile liquid material is between 50:1 and 1:1, preferably between 20:1 and 2:1, most preferably between 20:1 and 5:1.

In a preferred embodiment, the liquid volatile material comprises a solvent. Solvents improve the evaporation rate of the pyrethrins.

Preferably, said solvents promote stable, constant evaporation of the liquid volatile material. It is clear that the solvents must be physiologically acceptable, i.e. non-irritating, harmful to the health of mammals, in particular humans, non-corrosive and odorless.

In a preferred embodiment, the solvent comprises C6 to C20 hydrocarbons. More preferably, the solvent comprises predominantly linear and branched alkanes with a low aromatic content. More preferably, the solvent comprises predominantly or fully branched alkanes. In a more preferred embodiment, the solvent comprises at least one C8 to

C14 linear or branched alkane, most preferably isododecane. In another preferred embodiment, the solvent may be a petroleum distillate. Preferably the petroleum distillate has been hydrotreated. Hydrotreated petroleum distillates have lower levels of unsaturated and aromatic hydrocarbons, as well as nitrogen and sulfur compounds. Avoiding or reducing the amount of these compounds is desirable. More preferably, the solvent comprises a hydrotreated petroleum middle distillate comprising predominantly (i.e. at least 90% by weight) C14 to C19 hydrocarbons. In a preferred embodiment, the sum of linear and branched C6 - to

C20 alkanes in the liquid volatile material an amount of at least 30% by weight, preferably at least 50% by weight, more preferably at least 60% by weight, more preferably at least 70% by weight, more preferably at least 80% by weight, more preferably at least 85% by weight, more preferably at least 90% by weight.

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In a preferred embodiment, the sum of hydrotreated petroleum middle distillate and isododecane in the liquid volatile material is present in an amount of at least 30% by weight relative to the liquid volatile material, preferably at least 50% by weight, more preferably at least 60% by weight, more preferably at least 70% by weight, more preferably at least 80% by weight, more preferably at least 85% by weight, more preferably at least 90% by weight.

In a preferred embodiment, the liquid volatile material comprises a hydrotreated petroleum middle distillate (CAS No. 64742-46-7) and isododecane (CAS No. 13475-82-6). The inventors surprisingly discovered that such a mixture provides a stable, linear evaporation rate with sufficient evaporation to effectively repel mosquitoes. In a preferred embodiment, the hydrotreated petroleum middle distillate preferably comprises C14 to C19 hydrocarbons, isoalkanes, cyclics and less than 2% by weight aromatics. In a further preferred embodiment, the liquid volatile material comprises a hydrotreated petroleum middle distillate and isododecane in a weight ratio of at least 50/50, more preferably at least 70/30, more preferably at least 75/25, more preferably at least 80/ 20, more preferably at least 85/15, more preferably at least 90/10. In another preferred embodiment, the liquid volatile material comprises a hydrotreated petroleum middle distillate and isododecane in a weight ratio of at most 99/1, more preferably at most 97/3, more preferably at most 95/5, more preferably at most 93/ 7, more preferably at most 90/10. In another embodiment, the liquid volatile material comprises a hydrotreated petroleum middle distillate and isododecane in a ratio between 70/30 and 99/1, more preferably in a ratio between 75/25 and 97/3, more preferably in a ratio between 80 /20 and 95/5, more preferably in a ratio between 85/15 and 93/7, most preferably in a ratio of about 90/10. In a preferred embodiment, the total amount of hydrotreated petroleum middle distillate and isododecane in the liquid volatile material is at least 30% by weight relative to the liquid volatile material, preferably at least 50% by weight, more preferably at least 60% by weight. %, more preferably at least 70% by weight, more preferably at least 80% by weight, more preferably at least 85% by weight, more preferably at least 90% by weight.

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In a preferred embodiment, the wick comprises bonded polymer fibers.

Suitable polymers can be selected from the list of polyolefins, in particular polyethylene and polypropylene, PVC, polyamides and polyesters, in particular PET and PBT. Preferably, the bonded polymer fibers are twisted, creating a high tortuosity that produces a large number of small pores. In a preferred embodiment, the wick comprises bonded nylon fibers.

Nylon fibers refers to polyamide 6 or polyamide 6.6 fibers.

In the second aspect, the invention relates to a kit comprising: - a dispensing device comprising a heating device, - a wick, comprising a substrate of particles or fibers bonded together to form a body with a network of pores and passageways, and — a reservoir containing a liquid volatile material, wherein the liquid volatile material comprises carnosol, carnosic acid, a salt thereof or a mixture thereof and an insect control active ingredient.

The kit according to the second aspect can be advantageously assembled into a dispensing device according to the first aspect of the invention.

Furthermore, since the present invention relates to a composition that dramatically reduces the build-up of solid residue and clogging within the wick, the wick can be reused. In particular, a new reservoir can be installed, or the reservoir can be refilled with liquid volatile material.

In a preferred embodiment of the kit, the wick is attached to the dispensing device.

In another version of the kit, the wick is attached to the reservoir. In both preferred embodiments the wick is pre-mounted relative to either the dispensing device or the reservoir. This reduces the number of steps and parts required for consumer assembly, which improves safety and reduces the chance of incorrect assembly.

In a third aspect, the invention relates to a reservoir suitable for a dispensing device containing a liquid volatile material, said liquid volatile material comprising carnosol, carnosic acid, a salt thereof or a mixture thereof and an active ingredient for insect control. The reservoir according to the third aspect is suitable for use in combination with a

14 BE2022/5220 dispensing device according to the first aspect and a kit according to the second aspect.

It can be used advantageously to refill the dispensing device.

In one embodiment, the reservoir includes a wick. In another embodiment, the original wick can be reused and only a reservoir of liquid volatile material is provided. Preferably, the reservoir is sealed with a removable seal, such as a puncture seal.

It is clear that the preferred embodiments described herein for the first aspect of the invention also apply to the other aspects of the invention. In particular, all preferences regarding the liquid volatile material with respect to the dispensing device of the first aspect apply mutatis mutandis to the kit of the second aspect and the reservoir of the third aspect of the invention.

In a fourth aspect, the invention relates to a method of dispensing a volatile material from a dispensing device using a heating device (25) to promote the release of vaporized volatile materials (34) from a wick (31). designed to deliver a volatile material (34) from a reservoir (28) to a heated location within a heating device (25) in which the volatile material (34) can be heated and volatilized, the method comprising the steps of: provide as the volatile material of a liquid in the reservoir containing an insect control active ingredient; - providing as wick (31) a substrate comprising granular particles bonded together to form a body with a network of pores and passages, the inner surfaces of which are non-reactive and non-absorbent with respect to the substance to be delivered volatile material, wherein the body is shaped to occupy the heated location in the heating device, wherein activation of the volatile material release device releases the volatile material from the pores, which volatile material is then released; and - activating the heating device (25); wherein the liquid in the reservoir further contains carnosol, carnosic acid, a salt thereof or a mixture thereof.

In a preferred embodiment, the heating device is activated 6 to 12 hours per day, preferably 7 to 11 hours per day, more preferably 8 to 10 hours per day, most preferably approximately 9 hours per day.

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The invention is further described by the following non-limiting examples which further illustrate the invention and are not intended, nor should they be construed, to limit the scope of the invention.

The present invention will now be described in more detail with reference to examples which are not limiting.

DESCRIPTION OF THE FIGURES

For the purpose of better illustrating the properties of the invention, the following is given, by way of example and in no way limiting other potential applications, a description of some preferred applications of the method for examining the condition of the mortar being used in a mechanical connection based on the invention, where:

Referring to Figures 1A and 1B, a heated volatile dispensing device 20 is shown in which a heat source is used to promote capillary action and the release of a volatile material from a wick immersed in a volatile liquid in a reservoir.

The dispensing device 20 includes a body 21 with a vapor outlet 24 formed in the center of the top of the body 21. A heating ring 25 with an opening extending vertically therethrough is provided in the body 21 below the vapor outlet 24. The heating ring 25 is supported by a strut 26. Below the heater 25 is a bottle holder 27 with an opening extending vertically through it. The container 27 is formed at its inner periphery with a threaded portion 30 adapted for threaded engagement with a threaded portion 29 at the outer periphery of the mouth 28a of a volatile liquid bottle 28.

As shown in Figure 1B, the bottle 28 is provided with a wick 31 that can be inserted concentrically therewith into the heating ring 25 when the bottle 28 is screwed into the holder 27 at its mouth 28a. The wick 31 is immersed in the liquid 34 in the bottle 28 and transports the liquid 34 contained in the bottle 28 upwards by capillary action.

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Electrical plug pins 32 are attached in pairs to the body 21 at its rear. The plug pins 32 are connected to the heating ring 25 in the usual manner with electrical connections. The heating ring 25 is energized by plugging the plug pins 32 into an electrical socket and activating switch 35, causing the heating ring 25 to produce heat to heat the upper portion of the wick 31. The heat can promote the upward transport of the liquid 34 in the wick 31. The liquid chemical 34 in the wick 31 is vaporized by the heat of the heating ring 25. A more detailed description of this type of device can be found in U.S. Patent No. 5,290,546.

The wick 31 is made of the substrate discussed below, upon which even solutions containing natural pyrethrums can be delivered through the wick without clogging the wick, even over a period of forty-five, sixty or more eight-hour nights, which is typical usage expectations are for insect control products that deliver active ingredients for insect control via a wick to a heating appliance. Such a wick 31 can be cylindrical or have any other suitable shape.

Referring to Figures 2A and 2B, another heated volatile dispensing device 20a is shown in which a heat source is used to promote capillary action and the release of a volatile material from a wick immersed in a volatile liquid in a reservoir. The dispensing device 20a includes a body 21 with a vapor outlet 24a formed in the center of the top of the body 21. The vapor outlet 24a includes inwardly projecting fingers 24b defining a generally rectangular opening 24c. A heating ring 25 with an opening extending vertically through it is provided in the body 21 below the vapor outlet 24. The heating device 25 is supported by a strut 26. Underneath the heater 25 is provided a bottle holder 27 with an opening extending vertically through it. The container 27 is formed at its inner periphery with a threaded portion 30 adapted for threaded engagement with a threaded portion 29 at the outer periphery of the mouth 28a of a volatile liquid bottle 28.

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EXAMPLE 1 AND COMPARATIVE EXAMPLE 2

Solid residue accumulation was tested with two liquid volatile material compositions, each comprising 5 wt% natural pyrethrins. The first composition (Example 1) included 0.5% by weight rosemary extract. The rosemary extract was odorless and comprised 7 wt. % carnosic acid and carnosol combined, standardized with sunflower oil. The second composition (Comparative Example 2) included 0.25% by weight BHT.

For the BHT formulation (Comparative Example 2), solid residue accumulation was visible after approximately 240 hours of heating. After 350 hours of heating, significant degradation of the wick was visible. Figure 3B shows the blade of

Comparative Example 2 after 350 hours of heating.

The composition comprising carnosic acid and carnosol (Example 1) remained clean during use. Figure 3A shows the wick of Example 1 after 396 hours of heating.

The composition of Example 1 was further tested for its effectiveness against mosquitoes. Satisfactory results were obtained for heating for 12 hours per day and 9 hours per day during the 45 day test period.

COMPARATIVE EXAMPLES 3 AND 4

The evaporation profile of two liquid volatile material compositions was recorded, each consisting of natural pyrethrins and a solvent mixture comprising Isopar V and isododecane in a weight ratio of 9:1. Comparative

Example 3 included 10% by weight natural pyrethrins. Comparative Example 4 included 5% by weight of natural pyrethrins. Both compositions have been tested in combination with a wooden wick.

The evaporation profile was measured by heating for 8 hours per day for 45 days. The evaporation profile was fitted to a linear evaporation profile and the correlation coefficient was calculated. Since a linear, predictable evaporation profile is desired, correlation coefficients close to 1 are preferred. The modified linear evaporation profile also indicated the evaporation rate, which is the ratio of the time it takes for a compound to evaporate.

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For Comparative Example 4, linear evaporation was recorded for the entire 45 day period. The correlation coefficient of Comparative Example 4 was significantly higher than that of Comparative Example 3, thus better suited to the linear regression. In other words, the evaporation profile of

Comparative Example 4 was more linear. Comparative Example 4, with a lower natural pyrethrin content, also showed a higher evaporation rate

Example 3.

COMPARATIVE EXAMPLE 5

Comparative Example 5 was a repetition of Comparative Example 4, with the addition of 0.25% by weight BHT. In other words, Comparative Example 5 included 5% by weight of natural pyrethrins and a solvent mixture comprising Isopar V and isododecane in a weight ratio of 9:1. The composition further included 0.25% by weight BHT and was tested in combination with a wooden wick.

Comparative Example 5 showed a lower correlation coefficient for a linear evaporation with respect to Comparative Example 4, without BHT. It was also noticed that the evaporation rate decreased compared to Comparative Example 4.

COMPARATIVE EXAMPLE 6

In Comparative Example 6, the composition of Comparative Example 4 was tested in combination with a bonded nylon fiber wick instead of a wooden wick.

The evaporation profile of a liquid volatile material composition was recorded comprising 5% by weight natural pyrethrins and a solvent mixture comprising Isopar V and isododecane in a weight ratio of 9:1. This composition has been tested with a bonded nylon (polyamide 6) fiber wick.

For the composition in combination with a wick consisting of bonded nylon fibers (Comparative Example 6), linear evaporation was recorded for 44 days for heating 12 hours per day and resulted in a higher correlation coefficient with respect to the evaporation profile of the composition in combination with a wooden wick (Comparative Example 4). Comparative

Example 6 also showed a significantly higher evaporation rate than

Comparative Example 4. At the end of the test period there was solid residue

10 BE2022/5220 visible on the bonded nylon fiber wick near the heating element. The blade has been further expanded at this location.

EXAMPLE 7

The evaporation profile of a liquid volatile material composition was recorded comprising 5 wt% natural pyrethrins, a solvent mixture comprising Isopar V and isododecane in a weight ratio of 9:1 and 0.5 wt% rosemary extract. This composition (Example 7) was tested in combination with a wick comprising bonded nylon fibers.

For this composition (Example 7), linear evaporation was recorded and showed a significantly higher evaporation rate than the composition without rosemary extract (Comparative Example 6). For the composition including rosemary extract (Example 7), the wick remained clean during use.

After approximately 396 hours of heating, no accumulation of solid residue was visible.

Claims (16)

20 BE2022/5220 CONCLUSIONS A dispensing device comprising a reservoir (28); a liquid volatile material (34) in a reservoir (28); a heating device (25); a wick (31) designed to deliver the volatile material (34) from the reservoir (28) to a heated location within the heater (25) to promote the release of vaporized volatile material from the wick (31); wherein the volatile material (34) in the reservoir comprises an insect control active ingredient; and the wick (31) comprises a substrate of particles or fibers bonded together to form a body with a network of pores and passageways, the inner surfaces of which are non-reactive and non-absorbent with respect to the volatile material (34 ) to be delivered, the body being shaped to occupy the heated location in the heater (25), activation of the volatile release device releasing the volatile material from the pores, which volatile material is then released when the heating device (25) is activated; characterized in that the liquid volatile material comprises carnosol, carnosic acid, a salt thereof or a mixture thereof. 2. Dispensing device according to claim 1, wherein the total of carnosol, carnosic acid and salts thereof is between 0.001 and 0.1% by weight relative to the liquid volatile material. 3. Dispensing device according to any one of the preceding claims 1-2, wherein the active ingredient for insect control comprises natural pyrethrins, preferably comprising natural pyrethrins in an amount of 1.0 to 10.0% by weight with respect to the weight of the liquid volatile material. 4. Dispensing device according to any one of the preceding claims 1-3, wherein the carnosol, carnosic acid, a salt thereof or a mixture thereof is derived from rosemary (Rosmarinus officinalis) extract. 5. Dispensing device according to claim 4, wherein the rosemary extract is odorless. 6. Dispensing device according to any one of claims 4 and 5, comprising 1.0 to 10.0% by weight rosemary extract relative to the liquid volatile material. 21 BE2022/5220 Dispensing device according to any one of claims 1 to 6, wherein the liquid volatile material comprises a hydrotreated petroleum middle distillate and isododecane, preferably in a weight ratio between 50/50 and 95/5. 8. Dispensing device according to any of the preceding claims 1-7, wherein the wick comprises bonded nylon fibres. 9. Kit comprising: - a dispensing device comprising a heating device, - a wick comprising a substrate of particles or fibers bonded together to form a body with a network of pores and passageways, and - a reservoir containing a liquid volatile material wherein the liquid volatile material comprises carnosol, carnosic acid, a salt thereof or a mixture thereof and an insect control active ingredient. Kit according to claim 9, wherein the insect control active ingredient comprises natural pyrethrins. 11. Kit according to one of claims 9 or 10, wherein the wick is attached to the dispensing device. 12. Kit according to any one of claims 9-11, wherein the wick is attached to the reservoir. 13. Reservoir suitable for a dispensing device, comprising a liquid volatile material, said liquid volatile material comprising carnosol, carnosic acid, a salt thereof or a mixture thereof and an active ingredient for insect control. Reservoir according to claim 13, wherein the insect control active ingredient comprises natural pyrethrins. 15. A method of delivering a volatile material from a dispensing device that uses a heater (25) to promote the release of vaporized volatile materials (34) from a wick (31) 22 BE2022/5220 designed to deliver a volatile material (34) from a reservoir (28) to a heated location within a heating device (25) in which the volatile material (34) can be heated and volatilized, the method comprising the steps of: — providing as the volatile material a liquid in the reservoir containing an active ingredient for insect control; - providing as a wick (31) a substrate comprising granular particles bonded together to form a body with a network of pores and passages, the inner surfaces of which are non-reactive and non-absorbent with respect to the material to be removed deliver volatile material, wherein the body is shaped to occupy the heated location in the heater, wherein activation of the volatile material release device releases the volatile material from the pores, which volatile material is then released; and - activating the heating device (25); characterized in that the liquid in the reservoir further contains carnosol, carnosic acid, a salt thereof or a mixture thereof. A method according to claim 15, wherein the heating device is activated 6 to 12 hours per day, preferably 7 to 11 hours per day, more preferably 8 to 10 hours per day, most preferably about 9 hours per day.