Mosquito-repelling candle

Abstract

The present invention is broadly directed to a mosquito-repelling candle of a multi-phase construction (10) broadly comprising: an inner core (12) within which a wick (14) is embedded and partly exposed for lighting; an outer casing (16) surrounding the inner core (12) which on melting provides controlled heating of the outer casing (16) for activation of mosquito repellent within the outer casing (16). The controlled heating of the outer casing (16) is effective in releasing the mosquito repellent into the air for repelling mosquitoes. The controlled heating mechanism provided by the candle (10) provides release of the mosquito repellent whilst avoiding combustion of this active component of the candle (10).

Description

MOSQUITO-REPELLING CANDLETechnical FieldThe present invention is broadly directed to a mosquito-repelling candle of a multiphase construction and a manufacturing method thereof. The invention also generally relates to a composition of an outer layer of a mosquito-repelling candle of a multi-phase construction.Background

[0002] In Australia, existing “natural” insect control products including candles predominantly utilise the active ingredient of citronella. The citronella-based products have minimal effect in repelling mosquitoes. However, due to the active ingredient being used for decades, these products have been provided an exemption for testing prior to product release. This allows any and all products using citronella, to claim and advertise that their products protect and repel mosquitoes. The citronella-based products do not only come in the form of candles, but also as coils and incense sticks. All of these existing products provide a low level of efficacy in repelling mosquitoes.Summary of Invention

[0003] According to a first aspect of the present invention there is provided a mosquito-repelling candle of a multi-phase construction comprising: an inner core within which a wick is embedded and partly exposed for lighting, said inner core including wax which in use melts under the influence of heat from the lit wick; an outer casing surrounding the inner core which on melting of the wax provides controlled heating of said outer casing for activation of a mosquito repellent within the outer casing thereby releasing said repellent into the air for repelling mosquitos.

[0004] According to a second aspect of the invention there is provided a method of manufacturing a mosquito-repelling candle of a multi-phase construction, said method comprising:producing an inner core within which a wick is embedded and partly exposed for lighting, said inner core including wax which in use melts under the influence of heat from the lit wick; surrounding the inner core with an outer casing including a mosquito repellent which in use is activated on heating from melted wax of the inner core thereby releasing said repellent into the air for repelling mosquitos.

[0005] According to a third aspect of the invention there is provided a composition of an outer casing of a mosquito-repelling candle of a multi-phase construction, said composition comprising a mosquito repellent including pyrethrin and piperonyl butoxide in effective amounts for controlled release of said repellent for repelling mosquitos.

[0006] Preferably the mosquito repellent of the outer casing includes pyrethrin in its naturally derived non-synthetic form. More preferably the mosquito repellent includes pyrethrin combined with piperonyl butoxide in effective amounts for controlled release of said repellent for repelling mosquitos. More preferably the outer casing includes each of the pyrethrin and piperonyl butoxide at weight concentrations relative to the total weight of the inner core and the outer casing of around 0.5% to 3.0%w / w and 2.0% to 5.0% w / w respectively.

[0007] Preferably the outer casing also includes wax, and a fragrance. More preferably the wax of the outer casing includes paraffin wax and soy wax. Even more preferably the fragrance of the outer casing includes geraniol or another monoterpenoid or alcohol. Still more preferably the outer casing includes said fragrance at a weight concentration relative to the total weight of the inner core and the outer casing of between around 3.0% to 7.0% w / w.

[0008] Preferably the wax of the inner core includes paraffin wax and soy wax.

[0009] Preferably the inner core is shaped cylindrical and the outer casing surrounds the inner core in a cylindrical annulus. More preferably the outer casing is contained within a vessel configured to retain melted wax of at least the inner core.

[0010] Preferably the outer casing is in the form of an inverted cup including an enclosed perimeter wall and a ceiling together surrounding and in contact with the inner core. More preferably the wick associated with inner core protrudes through the ceiling of the outer casing and is thus in part exposed for lighting of said wick. Even more preferably a lower surface of the inner core, and lower surface of the perimeter wall of the outer casing are configured to contact an upper facing surface of a base of the vessel.

[0011] Preferably the ratio of the volume of the inner core relative to the volume of the outer casing is between 1.5 and 2.5 wherein the inner core provides controlled heating of the outer casing for release of the mosquito repellent over a predetermined period of time. More preferably the ratio of the wall thickness of the outer casing relative to the height of the outer casing is between 0.1 to 0.2. Even more preferably this dimensional configuration of the inner core and the outer casing enables release of the mosquito repellent for between 18 to 32 hours.Brief Description of Drawings

[0012] In order to achieve a better understanding of the nature of the present invention, preferred embodiments of a mosquito-repelling candle of a multi-phase construction and a manufacturing method thereof will now be described, by way of example only, with reference to Figure 1 which is a sectional view of an embodiment of a mosquito-repelling candle of a multi-phase construction according to a first aspect of the technology.Detailed Description

[0013] As seen in figure 1 , there is an embodiment of a mosquito-repelling candle of a multi-phase construction 10 of a first aspect of the invention broadly comprising: an inner core 12 within which a wick 14 is embedded and partly exposed for lighting; an outer casing 16 surrounding the inner core 12 which on melting provides controlled heating of the outer casing 16 for activation of a mosquito repellent within the outer casing 16.

[0014] It is to be understood that the controlled heating of the outer casing 16 is effective in releasing the mosquito repellent into the air for repelling mosquitos. In this embodiment the inner core 12 predominantly consists of wax which in use melts under the influence of heat from the lit wick 14. The controlled heating mechanism provided by the candle 10 of this construct provides release of the mosquito repellent whilst avoiding combustion of this active component of the candle 10.

[0015] In this embodiment the mosquito repellent of the outer casing 16 includes pyrethrin or pyrethroids in their naturally derived forms, or other organic compounds derived or extracted from naturally occurring pyrethrum. In this case, pyrethrin is provided in the form of pyrethrum PY-T-50 being a refined natural pyrethrum insecticide of Sumitomo Chemical Australia, or an equivalent. In this example, the natural pyrethrin is combined with piperonyl butoxide in an effective amount for controlled release of the mosquito repellent. The outer casing 16 of this embodiment includes each of the pyrethrin and piperonyl butoxide at weight concentrations relative to the total weight of the inner core 12 and the outer casing 16 of between 0.5% to 3.0%w / w and between 2.0% to 5.0%w / w respectively.

[0016] In this embodiment the outer casing 16 also includes wax and fragrance. The wax of the outer casing 16 forms the vast majority of the casing 16 and includes a mixture of waxes.

[0017] In this embodiment the wax of the inner core 12 forms the vast majority of the core 12 and includes a mixture of waxes. The inner core 12 is integrated with the wick 14 in the form of a cotton wick such as the high temperature paper (HTP) 105 wick and stay or equivalent. This cotton wick 14 is understood to have a burn diameter of between 68 to 72mm.

[0018] In this embodiment the inner core 12 is shaped cylindrical and the outer casing 16 surrounds the inner core in a cylindrical annulus. The outer casing 16 is contained within a cylindrical vessel or container 18 configured to retain melted wax of the inner core 12 and outer casing 16. In this example, the vessel 18 is provided in one of three standard size categories each having a predetermined inside diameter to accommodate the outer casing 16 of the mosquito repellent candle 10. It is to be understood that within each of the three size categories, the vessel 18 will be ofdifferent heights to accommodate different sized mosquito-repelling candles such as 10.

[0019] In this example the outer casing 16 is in the form of an inverted cup including an enclosed perimeter wall 20 and a ceiling 22 together surrounding and in contact with the inner core 12. The wick 14 associated with the inner core 12 protrudes through the ceiling 22 of the outer casing 16 and is thus in part exposed for lighting. In this construction of the mosquito-repelling candle 10, a lower surface 24 of the inner core 12, and lower surface 26 of the perimeter wall 20 of the outer casing 16 contact an upper facing surface 28 of a base 30 of the vessel 18.

[0020] In this embodiment the mosquito-repelling candles are sized according to the total weight of the inner core 12 and outer casing 20, the weight of the wick 14 being considered negligible. For illustrative purposes only, the geometry and composition of the mosquito-repelling candle 10 will be described in the context of candles sized at 125 grams, 250 grams and 400 grams. The vessel 18 associated with respective of each of these three (3) sized candles has an inner diameter of 66mm and height of 70mm (125 gram), an inner diameter of 77mm and height of 80mm (250 grams), and an inner diameter of 96mm and height of 90mm (400 grams). The mosquito-repelling candle 10 may be sized anywhere from 100 grams to 500 grams wherein the inside diameter for each of the three sized categories remains the same and the height varies to accommodate the different sizes within each range.

[0021] In this example, the inner core 12 and the outer casing 16 are produced in the following dimensions:Inner CoreOuter Casing

[0022] In these embodiments the cup-shaped outer casing 16 encases the inner core 12. The ceiling 22 of the outer casing 16 is of a thickness represented by the difference in heights of the outer casing 16 and the inner core 12. The ceiling 16 may thus be of a thickness of anywhere from between 5mm to 10mm.

[0023] It is to be understood that the relative sizes and volumes of the inner core 12 and the outer casing 16 are important in controlling heating of the outer casing 16 for controlled release of the mosquito repellent with the required efficacy. The volume or mass of the inner core 12 is also important in providing the heat source for the controlled heating of the outer casing 16. Furthermore, the ratio of the wall thickness of the outer casing 16 relative to its height is important in regulating heating of the mosquito repellent to control its release from the candle 10. As reflected in the preceding constructs of the mosquito-repelling candles 10, it should be noted that the:1. ratio of the volume of the inner core 12 relative to the volume of the outer casing 16 is between 1.0 and 2.5;2. the ratio of the wall thickness of the outer casing 16 relative to the height of the outer casing 16 is between 0.1 to 0.2.

[0024] These preferred dimensional constraints for the mosquito-repelling candle 10 and in particular this dimensional configuration of the inner core 12 and the outer casing 16 enables controlled release of the mosquito repellent at the required efficacy for between 18 to 32 hours. In this embodiment the mosquito repellent in the form of the pyrethrin and piperonyl butoxide are relatively expensive and the preferred constructs of the mosquito-repelling candle enable release of the repellent for extended periods with relatively low concentrations of these active ingredients within the outer casing 16. In this example, the weight concentrations of each of the pyrethrin and piperonyl butoxide for the candles of the three sizes is relatively low at around 0.5% to 3.0%w / w and 2.0% to 5.0%w / w (expressed as 100% concentrate and based on total weight of the inner core and outer casing).

[0025] For illustrative purposes only, the following table provides a breakdown of the composition or “formula” expressed as a single candle 10.;

[0026] It is to be understood that wick weights may vary and alternative wicks may be used which are comparable with the listed wicks. It is to be understood that the fragrance or geraniol is included at 97% concentration although it may be increased to 100% concentration depending on regulatory requirements.

[0027] In a second aspect of the invention there is a method of manufacturing a mosquito-repelling candle of a multi-phase construction. For ease of reference this manufacturing method will be described in the context of the multi-phase candle 10 of the preceding embodiments of the first aspect. The manufacturing method broadly comprises:1. producing an inner core 12 within which a wick 14 is embedded and partly exposed for lighting;2. surrounding the inner core 12 with an outer casing 16 including a mosquito repellent which in use is activated from heat of wax of the inner core 12.

[0028] In this embodiment the candle 10 is manufactured in two phases, namely (i) the inner core 12 formulated with waxes together with an associated wick, and (ii) an outer casing 16 formulated with waxes, the mosquito repellent as an active ingredient and fragrance. It will be understood that the inner core 12 may be produced separate from the outer casing 16. In this scenario the pre-fabricated inner core 12 and its associated wick 14 are placed centrally within the vessel 18 contacting its base 30, and thereafter the outer casing 16 in a preformulated liquid form is poured into the vessel 18. In an alternative approach the inner core 12 is placed centrally in a female mould (not shown) and the outer casing 16 poured into the mould to formSUBSTITUTE SHEET (RULE 26)about said core 12. The moulded candle is then removed from the mould and the wick 14 inserted through an axial hole (not shown) preformed in the inner core 12 so that it protrudes above the candle 10. The moulded candle is then placed within the complementary shaped vessel 18.

[0029] In a third aspect of the invention there is a composition of an outer casing of a mosquito-repelling candle of a multi-phase construction. For convenience the composition will be described in the context of the multi-phase candle 10 of the described embodiments of the first aspect. The composition generally comprises a mosquito repellent including pyrethrin in its naturally derived form, and piperonyl butoxide each in effective amounts for controlled release of the mosquito repellent. The preceding disclosures pertaining to the mosquito-repelling candle 10 of the preferred embodiment disclose exemplary effective amounts of the pyrethrin and piperonyl butoxide.

[0030] Now that preferred embodiments of the various aspects of the technology have been described it will be apparent to the skilled in the art that the mosquitorepelling candle of a multi-phase construction and a manufacturing method thereof have at least the following advantages:1. the candles are constructed wherein an effective amount of mosquito repellent is released over a prolonged period;2. the multi-phase candles are configured and produced with minimal mosquito repellent whilst remaining effective in repelling mosquitos for extended periods;3. the candle is relatively inexpensive to produce where its multi-phase construction allows minimal amounts of expensive mosquito repellents including pyrethrin in its naturally derived form which is particularly effective in repelling mosquitos.

[0031] Those skilled in the art will appreciate that the invention as described herein is susceptible to variations and modifications other than those specifically described. For example, the configuration of the mosquito-repelling candle may depart from the described cylindrical form where it is of a quadrilateral or other multisided form. The candle may include more than the two phases described and illustrated and remain within the scope of the invention. The formula or chemistry forthe candle and in particular its outer casing may vary provided it enables controlled release of a mosquito repellent under the heating influence of the inner core.

[0032] All such variations and modifications are to be considered within the scope of the present invention the nature of which is to be determined from the foregoing description.

Claims

Claims1. A mosquito-repelling candle of a multi-phase construction comprising: an inner core within which a wick is embedded and partly exposed for lighting, said inner core including wax which in use melts under the influence of heat from the lit wick; an outer casing surrounding the inner core which on melting of the wax provides controlled heating of said outer casing for activation of a mosquito repellent within the outer casing thereby releasing said repellent into the air for repelling mosquitos.

2. A candle as claimed in claim 1 wherein the mosquito repellent of the outer casing includes pyrethrin in its naturally derived non-synthetic form.

3. A candle as claimed in claim 2 wherein the mosquito repellent includes pyrethrin combined with piperonyl butoxide in effective amounts for controlled release of said repellent for repelling mosquitos.

4. A candle as claimed in claim 3 wherein the outer casing includes each of the pyrethrin and piperonyl butoxide at weight concentrations relative to the total weight of the inner core and the outer casing of around 0.5% to 3.0%w / w and 2.0% to 5.0% w / w respectively.

5. A candle as claimed in any one of the preceding claims wherein the outer casing also includes wax and a fragrance.

6. A candle as claimed in claim 5 wherein the wax of the outer casing includes paraffin wax and soy wax.

7. A candle as claimed in either of claims 5 or 6 wherein the fragrance of the outer casing of the outer casing includes geraniol or another monoterpenoid or alcohol.

8. A candle as claimed in any one of claims 5 to 7 wherein the outer casing includes said fragrance at a weight concentration relative to the total weight of the inner core and the outer casing of between around 3.0% to 7.0% w / w.

9. A candle as claimed in any one of the preceding claims wherein the wax of the inner core includes paraffin wax and soy wax.

10. A candle as claimed in any one of the preceding claims wherein the inner core is shaped cylindrical and the outer casing surrounds the inner core in a cylindrical annulus.

11. A candle as claimed in claim 10 wherein the outer casing is contained within a vessel configured to retain melted wax of at least the inner core.

12. A candle as claimed in claim 11 wherein the outer casing is in the form of an inverted cup including an enclosed perimeter wall and a ceiling together surrounding and in contact with the inner core.

13. A candle as claimed in claim 12 wherein the wick associated with inner core protrudes through the ceiling of the outer casing and is thus in part exposed for lighting of said wick.

14. A candle as claimed in any one of claims 11 to 13 wherein a lower surface of the inner core, and lower surface of the perimeter wall of the outer casing are configured to contact an upper facing surface of a base of the vessel.

15. A candle as claimed in any one of the preceding claims wherein the ratio of the volume of the inner core relative to the volume of the outer casing is between 1.5 and 2.5 wherein the inner core provides controlled heating of the outer casing for release of the mosquito repellent over a predetermined period of time.

16. A candle as claimed in claim 15 wherein the ratio of the wall thickness of the outer casing relative to the height of the outer casing is between 0.1 to 0.2.

17. A candle as claimed in either of claims 15 or 16 wherein this dimensional configuration of the inner core and the outer casing enables release of the mosquito repellent for between 18 to 32 hours.

18. A composition of an outer casing of a mosquito-repelling candle of a multiphase construction, said composition comprising a mosquito repellent includingpyrethrin and piperonyl butoxide in effective amounts for controlled release of said repellent for repelling mosquitos.

19. A composition as claimed in claim 18 wherein the mosquito repellent of the outer casing includes pyrethrin in its naturally derived non-synthetic form.

20. A composition as claimed in claim 19 wherein the mosquito repellent includes pyrethrin combined with piperonyl butoxide in effective amounts for controlled release of said repellent for repelling mosquitos.21 . A composition as claimed in any one of claims 18 to 22 wherein the outer casing also includes wax and a fragrance.

22. A composition as claimed in 21 wherein the wax of the outer casing includes paraffin wax and soy wax.

23. A composition as claimed in either of claims 21 or 22 wherein the fragrance of the outer casing includes geraniol or another monoterpenoid or alcohol.

24. A method of manufacturing a mosquito-repelling candle of a multi-phase construction, said method comprising: producing an inner core within which a wick is embedded and partly exposed for lighting, said inner core including wax which in use melts under the influence of heat from the lit wick; surrounding the inner core with an outer casing including a mosquito repellent which in use is activated on heating from melted wax of the inner core thereby releasing said repellent into the air for repelling mosquitos.

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