CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This utility non-provisional patent application claims the benefit of priority to U.S.

Provisional Patent Application Serial No. 62/253,850, filed November 11, 2015. The entire contents of U.S. Provisional Patent Application Serial No. 62/253,850 are incorporated by reference into this utility non-provisional patent application as if fully rewritten herein.

STATEMENT OF GOVERNMENT SPONSORSHIP [0002] Not applicable.

BACKGROUND OF THE INVENTION

Field of the Invention [0003] Embodiments relate to candles that contain pyrethrum.

Background of the Related Art

[0004] Pyrethrum is a natural insecticide that is made from dried heads of flowers of the genus Chrysanthemum. Pyrethrum typically includes compounds known as pyrethrins, which are natural organic compounds derived from Chrysanthemum cinerariifolium. Pyrethrins act as insect neurotoxins. At lower concentrations pyrethrins are also useful as insect repellants.

[0005] Typically pyrethrins that are used as insecticides are prepared by crushing seed cases of the Chrysanthemum plants, followed by a series of solvent extractions. A flowchart for a typical production is shown in FIG. 1. These solvent extractions allow concentration and purification of the pyrethrins. Pyrethrins may be divided into pyrethrin I and pyrethrin II, as shown in Formula I:

[0007] where, for pyrethrin I the R substituent is -CH3, and where, for pyrethrin II the R substituent is -C0 ₂ CH ₃ .

[0008] The solvent extraction is not without disadvantages. One disadvantage of the solvent extractions is the significant amount of waxy residue that results from the extraction. This black, waxy residue has previously had no beneficial use, resulting in a costly waste product from pyrethrin production. This residue includes a variety of components, not least of which are pyrethrins that might otherwise have been used as insecticides and/or insect repellents.

[0009] Attempts to make beneficial use of the pyrethrum wax have failed. This is believed to be due to the fact that traditional attempts have focused on use of the unmodified pyrethrum wax as part of a traditional wicked candle. These unmodified pyrethrum wax candles have proven to be unsatisfactory because the pyrethrum wax fails to burn for any satisfactory length of time.

[0010] A number of alternatives have been suggested for distribution of pyrethrin. For

example, PCT International Patent Application No. WO2010/139996, incorporated by reference herein, reports a vaporizer that includes pyrethrum and that may be attached to a conventional candle. Neither the vaporizer nor the pyrethrum itself is integral to or integrated with the candle.

[0011] United States Patent No. 2,918,750, incorporated by reference herein, reports a multilayer structure including a standard paraffin wax candle surrounded by one or more shells, one of which may be a pyrethrum shell. Like the previously-discussed publication, the pyrethrum is not incorporated within the wax.

[0012] Chinese Patent Application No. CN1115783 reports preparation of a candle including pyrethroids or natural pyrethrum esters, but does not report use of the pyrethrum wax solvent extraction byproduct in any candle. The unsuitability of pyrethroids for use in wax candles is reported, for example, in U.S. Patent No. 7,258,868, which reports the clogging of candle wicks by non-volatile waxes formed during heating of pyrethrum. Pyrethrum wax is particularly unsuitable for use, because its inclusion in typical candle wax formations results in preparation of candles that self-extinguish in less than one hour of burning. BRIEF SUMMARY OF THE INVENTION

[0013] We have found that the black, waxy residue of solvent extraction of pyrethrins

(referred to herein as "pyrethrum wax"), previously considered a waste product, may be beneficially incorporated into a wax-based delivery system with insect-repellent properties. Such wax -based delivery systems typically include, in combination with the pyrethrum wax, one or more added pyrethroids, pyrethroid synergists, inert ingredients (including, for example, but not limited to waxes and oils used to create a candle matrix), fuels and co- solvents, and stabilizers.

[0014] It should be noted that although typical embodiments are described in the context of candles, these embodiments may also be useful as a more general wax -based delivery system, without a wick. These may be used, for example, in wax warmers. As discussed in this application, compositions are described in terms of the weight of the components as a percentage of the wax-based delivery system excluding any wick in the case of a candle or any structural support for a wax warmer.

[0015] In one embodiment, we provide an insect-repellent wax-based delivery system having the composition shown in Table 1 :

[0016] A further embodiment provides a candle having the composition shown in Table 2.

Table 2

[0017] A further embodiment provides a candle having the composition shown in Table 3.

Table 3

[0018] Embodiments of the disclosure relate to a wax -based delivery system comprising: pyrethrum wax; and a hydrocarbon solvent comprising light petroleum distillates of C7-C16 hydrocarbons, wherein the pyrethrum wax and the hydrocarbon solvent are present in the system by weight in a ratio of pyrethrum wax to hydrocarbon solvent between 40:60 and 60:40.

[0019] In further embodiments, the ratio of pyrethrum wax to hydrocarbon solvent is about 50:50.

[0020] In further embodiments, the wax-based delivery system further comprises a second wax, an antioxidant, a stabilizer, and a co-solvent.

[0021] In further embodiments, the wax-based delivery system further comprises at least one member of the group consisting of a pure pyrethrum, pyrethroids synergist, a carbamate- based enzyme inhibitor, a pyredine-based growth inhibitor, and a peroxide scavenger.

[0022] In further embodiments, the system is a candle and the pyrethrum wax is present in an amount of from 1-10% of the system.

[0023] In further embodiments, the active ingredient level of pyrethrum is maintained by the addition of pyrethrum in the amount from 0.1 - 2%. In some of these embodiments, the pyrethrum is pyrethrin. [0024] In further embodiments, the wax -based delivery system comprises paraffin wax in an amount between 2% and 90% by weight of the system.

[0025] In further embodiments, the hydrocarbon solvent comprises at least one solvent

selected from the group consisting of CI 1-C16 isoalkane hydrocarbons and mineral spirits.

[0026] In further embodiments, the hydrocarbon solvent comprises CI 1-C16 isoalkane

hydrocarbons.

[0027] In further embodiments, the hydrocarbon solvent comprises mineral spirits.

[0028] In further embodiments, the wax-based delivery system comprises at least 1% by weight of at least one pyrethrin.

[0029] In further embodiments, the wax-based delivery system further comprises a wick, wherein the wick comprises a cotton flat braided wick and a paper filament, wherein the paper filament is crisscrossed on the outside of the cotton flat braided wick, and wherein the wick is treated with a high temperature melting wick wax.

[0030] In an embodiment, the wax-based delivery system further comprises a wick, wherein the wick is a bleached, loose square braided wick consisting of cotton that is treated with a high temperature melting wick wax.

[0031] In an embodiment, the wax-based delivery system further comprises a heater plate.

[0032] Embodiments of the disclosure relate to a method for repelling insects, comprising: heating any of the aforementioned wax -based delivery systems.

[0033] In further embodiments, said wax -based delivery system is heated in a wax warmer for a period of 1-8 hours at a constant temperature between 45°C - 80°C until the solid wax blend has melted thereby releasing the active pyrethrum into the environment.

[0034] Embodiments of the disclosure relate to a method for preparing a pyrethrum wax- based delivery system, comprising: mixing pyrethrum wax and hydrocarbon solvent comprising a mixture of CI 1-C16 isoalkane hydrocarbons, wherein the pyrethrum wax and the hydrocarbon solvent is present in the system by weight in a ratio of pyrethrum wax to hydrocarbon solvent between 40:60 and 60:40 pyrethrum wax to hydrocarbon solvent; adding the mixture of pyrethrum wax and hydrocarbon solvent to a molten wax selected from the group consisting of paraffin wax and saturated fatty acid; and cooling the mixture. [0035] In further embodiments, the pyrethrum wax is dissolved in a hydrocarbon solvent at 50°C and added to a molten mixture of paraffin wax and fatty acid at 75°C followed by addition of a peroxide scavenger and pure pyrethrum, mixed until uniform and poured into a container.

[0036] In further embodiments, the mixture is cooled around a wick.

[0037] In further embodiments, the wick comprises a cotton flat braided wick and a paper filament, wherein the paper filament is crisscrossed on the outside of the cotton flat braided wick, and wherein the wick is treated with a high temperature melting wick wax.

[0038] In an embodiment, the wick is a bleached, loose square braided wick consisting of cotton that is treated with a high temperature melting wick wax.

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG. 1 shows a flowchart for a typical pyrethrin production.

[0040] FIG. 2 shows a release profile for insecticide from the pyrethrum wax candle tested according to Example 1.

DETAILED DESCRIPTION OF THE INVENTION

[0041] Hereinafter, illustrative embodiments and examples will be described in detail so that inventive concept may be readily implemented. However, one should note that the present disclosure is not limited to the illustrative embodiments and examples but can be realized in various other ways. In drawings, parts irrelevant to the description are omitted for the simplicity of explanation, and like reference numerals denote like parts through the whole document. Through the whole document, the term "comprises or includes" and/or

"comprising or including" used in the document means that one or more other components, steps, operation and/or existence or addition of elements are not excluded in addition to the described components, steps, operation and/or elements unless context dictates otherwise. The term "about or approximately" or "substantially" are intended to have meanings close to numerical values or ranges specified with an allowable error.

[0042] Candles as reported herein include pyrethrum wax, which is the black, waxy residue of solvent extraction of pyrethrins. Solvent extraction of pyrethrins from dried pyrethrum flowers is well-known to those of skill in the art, as reflected, for example, by U.S. Patent No. 3,083, 136, which issued on March 26, 1963, to Levy, and which is incorporated by reference herein. As reported by Levy, multiple organic solvents may be suitable for use in the extraction, including hexane, petroleum ether, solvent naphtha, and kerosene. Mixed solvents may also be used.

[0043] As further noted by Levy, preferred extraction methods remove pyrethrum but do not remove other natural constituents of the pyrethrum flowers, including color, fats, waxes, and other materials. These materials, along with unseparated pyrethrins, are components of pyrethrum wax.

[0044] Pyrethrum wax is a vegetable wax consisting of compounds from the pyrethrum

flower that are soluble in hexane and insoluble in cold methanol. It is a byproduct of the pyrethrins extraction process and contains the unseparated pyrethrins.

[0045] Pyrethrum wax includes multiple pyrethrins, including pyrethrin 1, pyrethrin 2,

cinerin 1, cinerin 2, jasmolin 1, and jasmolin 2. Typically pyrethrum wax may contain up to 1% of pyrethrin. Pyrethrum wax may contain butylated hydroxytoluene. The remainder may be organic-based hydrocarbon materials. Pyrethrum wax is available, for example, as product number Rl 79805 from McLaughlin Gormley King Company. More information on Rl 79805 may be found, for example, in the October 22, 2013 McLaughlin Gormley King Company's Material Safety Data Sheet for Pyrethrum Waxes, which is incorporated by reference herein.

[0046] During preparation of candles or other wax structures according to embodiments of the invention, the native amount of pyrethrin in the pyrethrum wax is typically supplemented by addition of pyrethrins until the candle is at least 1% pyrethrins by weight. Note that in some cases pyrethrin 1, cinerin 1, and jasmolin 1 have been referred to as members of the "Pyrethrin I" group, but references to pyrethrin 1 herein are to the specific compound shown in Formula (I), where, for pyrethrin 1 the R substituent is -CH ₃ . Similarly, pyrethrin 2, cinerin 2, and jasmolin 2 have been referred to as members of the "Pyrethrin II" group, but references to pyrethrins 2 herein are to the compound of Formula (I), where for pyrethrin 2 the R substituent is -C02CH3

[0047] As previously discussed, prior efforts to make beneficial use of the pyrethrum wax as an insect repellent have failed. This failure is primarily due to the inability of even skilled technicians to prepare a candle composition that does not clog a wick after a short period of use, rendering the candle unusable. Typical attempts have resulted in candles that self- extinguish after less than one hour of burning.

[0048] We have surprisingly found that the disadvantages previously associated with

inclusion of pyrethrum wax in a candle may be overcome by combination of the pyrethrum wax with a hydrocarbon solvent that leads to a clean, efficient burn of the candle. In certain embodiments this may be accomplished by mixture of pyrethrum wax with hydrocarbon solvent in a ratio, by weight, of between 40 to 60 percent pyrethrum wax to 60 to 40 percent hydrocarbon solvent. In a preferred embodiment a 50/50 mixture of pyrethrum wax and hydrocarbon solvent may be used. Typically the hydrocarbon solvent and the pyrethrum wax are mixed prior to their addition to the other candle components at 50°C until a homogenous solution is obtained.

[0049] Examples of efficient burn (1" flame height) can be illustrated by the blending of various solvents with pyrethrum wax prior to addition to the candle matrix. A candle with Pyrethrum Wax and no solvent served as the negative control while the candle wax without any addition served as the positive control. The following solvents: diisopropyl adipate, benzyl benzoate, isopropyl myristate, CI 1-16 isoalkane hydrocarbon, dipropylene glycol monom ethyl acetate and diisodecyl adipate were mixed with pyrethrum wax and heated to 50°C until a uniform liquid was obtained. Candles were prepared using a paraffin wax / soy wax / petrolatum base. The pyrethrum wax / solvent blend was added at 20% to the candle wax base. Candles were burned and observed over a 5 hour period. The pyrethrum wax control candle self-extinguished in less than 60 minutes. The CI 1-16 isoalkane hydrocarbon / pyrethrum wax blend burned with a 1" flame for the entire 5 hour period. All other pyrethrum wax / solvent blends after 2 hours produced a ¼" flame or a glowing wick.

Neither are considered as an acceptable burn.

[0050] The hydrocarbon solvent used in the invention is typically a mixture of multiple hydrocarbons. Although not wishing to be bound by theory, the applicant believes that the hydrocarbon solvent, when present in sufficient amounts relative to the pyrethrum wax, acts as a supplemental fuel that permits a pyrethrum wax candle to continue to burn while others have failed.

[0051] The hydrocarbon solvent may include light petroleum distillates. Light petroleum distillates may include a mixture of C7-C16 hydrocarbons (where "C7-C16" refers to compounds having between 7 and 16 carbon atoms). In some embodiments, light petroleum distillates may include a mixture of C7-C12 hydrocarbons. In other embodiments, light petroleum distillates may include a mixture of CI 1-C16 hydrocarbons.

[0052] For example, a preferred embodiment includes Isopar™ M as the hydrocarbon solvent.

Isopar™ is a trademark of Exxon Mobil. Isopar™ M is a mixture of CI 1-C16 hydrocarbons, the main components of which are alkanes, isoalkanes, and cycloalkanes. Less than 2% of Isopar™ M is aromatics. More information on Isopar™ M may be found, for example, in the December 12, 2014, Exxon Mobil Safety Data Sheet for Isopar™ M fluid, which is incorporated by reference herein. Other suitable solvents include hydrocarbon fluids such as mineral spirits or deodorized kerosene which are obtained through fractional distillation of petroleum. The mineral spirits and deodorized kerosene may act as a co-solvent for the pyrethrum wax. Odorless mineral spirits may act as a co-solvent for the pyrethrum wax.

[0053] Mineral spirits have a characteristic unpleasant kerosene like odor. Mineral spirits are a mixture of aliphatic and alicyclic C7-C12 hydrocarbons. Mineral spirits are used as an extraction solvent, as a cleaning solvent, as a degreasing solvent and as a solvent in aerosols, paints, wood preservatives, lacquers, varnishes, and asphalt products. Chemical

manufacturers have developed a low odor version of mineral turpentine which contains less of the highly volatile shorter hydrocarbons. Odorless mineral spirits are mineral spirits that have been further refined to remove the more toxic aromatic compounds and are

recommended for applications such as oil painting, household cleaners and some personal care products where humans have close contact with the solvent.

[0054] Hydrocarbon selection is based upon 2 key factors: flash point and olfactive character.

The flash point of the solvent must be 10°C greater than the temperature of the molten pool when the candle is burning. The molten pool is approximately 55°C, which limits Isopar selection to the "M" grade with a flash point of 95°C. Isopar™ L and grades below have a maximum flash point of 62°C which make them too low for consideration. More information on Isopar™ L may be found, for example, in the December 12, 2014, Exxon Mobil Safety Data Sheet for Isopar™ L fluid, which is incorporated by reference herein. Deodorized kerosene a has a flash point range from 68-74°C and odorless mineral spirits is in the 67- 75°C, which make them suitable for use as well. The olfactive character is very important as most unpurified petroleum based products have a strong sulfur note which is highly objectionable from a sensory point of view. Multiple distillations and/or

hydrodesulfurization (removal of sulfur) provide a neutral odor hydrocarbon solvent suitable for use in a consumer product. Isopar™ M meets all of the criteria and has the lowest odor of any of the hydrocarbon solvents.

[0055] Candles provided in embodiments as reported herein will include components in

addition to the pyrethrum wax and the hydrocarbon solvent. For example, they may include an inert component such as paraffin wax; stearic acid; a fragrance retention polymer that enhances the ability to load fragrance into the wax, which may be Vybar™ brand

hyperbranched polyolefin; a stabilizer, and an antioxidant. More information on Vybar™ brand hyperbranched polyolefin may be found, for example, in the 2010 Baker Hughes Product Application Guide for Candle Additives, which is incorporated by reference herein.

[0056] In some embodiments the fragrance retention polymer that enhances the ability to load fragrance into the wax is Vybar™ brand polymer, which is a hyperbranched polyolefin that enhances oil binding, fragrance binding, opacification, hardness, and thermal stability. Vybar™ 260 Polymer is a blend of alpha polymerized alkenes with the CAS # 68527-08-2. Vybar™ 260 Polymer has a softening point of 54°C. At 25°C, penetration of Vybar™ 260 Polymer is 12 dmm according to ASTM D1321.

[0057] Many antioxidants are suitable for inclusion in embodiments as reported herein. For example, 2-tert-butylhydroquinone, commonly referred to as TBHQ, may be used. Other useful antioxidants include but are not limited to butylated hydroxytoluene (BHT); octadecyl- 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate (commonly sold under the trade name Irganox® 1076); pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxypehnyl)propionate (commonly sold under the trade name Tinogard® TT, or Irganox® 1010); tris(2,4-ditert- butylphenyl)phosphite (commonly sold as Irgafos® 168); 2,2'-ethylidenebis[4,6-di-tert- butylphenol (commonly sold as Tinogard® NO A), or blends thereof.

[0058] More information on Irganox® 1076 may be found, for example, in the October 1999 Ciba® Irganox® 1076 Phenolic Primary Antioxidant for Processing and Long-Term Thermal Stabilization, which is incorporated by reference herein.

[0059] More information on Tinogard® TT may be found, for example, in the February 2011 Tinogard® TT Technical Information pamphlet from BASF SE - Care Chemical Division, which is incorporated by reference herein. [0060] More information on Irgafos® 168 may be found, for example, in the August 2009 Ciba® Irgafos® 168 Hydrolytically Stable Phosphite Processing Stabilizer, which is incorporated by reference herein.

[0061] More information on Tinogard® NOA may be found, for example, in the January 2012 Tinogard® NOA Technical Information pamphlet from BASF SE - Home Care & Formulation Technologies Europe, which is incorporated by reference herein.

[0062] Many stabilizers are suitable for inclusion in embodiments as reported herein. For example, 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methyl-phenol (commonly sold under the trade name Tinogard® TL) is a useful stabilizer. More information on Tinogard® TL may be found, for example, in the April 2013 Tinogard® TL Technical Information pamphlet from BASF - Care Chemical Division, which is incorporated by reference herein.

[0063] Although paraffin wax is the most typical second wax and inert ingredient, other inert ingredients may be included. These include beeswax, candelilla wax, microcrystalline wax, soy wax, hydrogenated castor oil wax, petrolatum, hydrogenated glycerides, glyceryl stearate, carnauba wax, ozokerite, ceresine wax, hydrogenated alpha olefins, Fischer Tropsch wax, and polyethylene wax.

[0064] Although typical embodiments will include pyrethrum wax, a hydrocarbon solvent, a second wax, polymer loading enhancer, a stabilizer, and an antioxidant, other components may be included. These may include both natural and synthetic pyrethroids, pyrethroid synergists, enzyme inhibitors, growth inhibitors, oils, peroxide scavengers, fatty acids, fragrance and colorants.

[0065] Exemplary synthetic pyrethroids that may be included in embodiments as reported herein include bifenthrin, cypermethrin, cyphenothrin, D-trans allethrin, esfenvalerate, imiprothin, metofluthrin, permethrin, and prallethrin.

[0066] In an embodiment of an insect repellent candle, the insect repellent candle will be burned outdoors so the burning wick must be able to withstand wind without extinguishing. The preferred wick design for this application is a cotton flat braided wick with a paper filament crisscrossed on the outside in order to control the flame posture during burning. Another suitable wick configuration is a bleached, loose square braided wick made entirely of cotton. Both wicks are treated with a high temperature melting wick wax to maintain upright positioning during candle manufacturing. A high temperature melting wick wax has a melting point of about 90°C or higher. A high temperature melting wick wax may include a single ingredient. Other high temperature melting wick waxes include a blend.

[0067] Candles prepared according to embodiments of the invention typically include a wick.

A wick may be, for example, string, cord, or wood. In one embodiment the wick is a braided cotton wick. The wick may include a tether. Wicks are typically mordanted, and may be further treated with substances to improve flow of wax. These substances may be, for example, salt or borax. The wick may also be treated with a "wick wax" which is a high melting wax to maintain wick straightness and rigidity when the molten wax is poured into the candle

[0068] Embodiments may also include fragrance materials and/or additional materials that act as insect repellents. These may include, for example, but are not limited to fragrance materials approved by the Environmental Protection Agency (EPA) and listed on the

Minimum Risk Pesticide List 40 CFR 152.25(f)(1), which is incorporated by reference herein, which include cinnamon oil, citronella oil, clove oil, eugenol, geraniol, geranium oil, lemongrass oil, mint oil, peppermint oil, rosemary oil and thyme oil. All of these aroma chemicals exhibit insect repellency properties.

[0069] The addition of fragrance to impart a pleasant aroma while the candle is burning and to mask the odor of the pyrethrum wax is a sensory element that will enhance consumer acceptance of the finished product. A candle fragrance must be properly constructed as to not interfere with the burning characteristics of the finished candle from start to completion.

[0070] In certain embodiments, materials recited above are present in a candle in an amount within the ranges shown in Table 4:

Table 4

Polymer (e.g. Vybar™ polyolefin) 0.25-2.00

Hydrocarbon solvent 1-10%

Stabilizer 0.01-1.0%

[0071] One or more optional additives may be present according to the amounts shown in Table 5, in addition to the components in Table 4:

[0072] Table 5

[0073] Embodiments may be characterized by their long-burning characteristics. ASTM F2417-04 (Standard Specification for Fire Safety for Candles) defines a series of 4 hour burn protocols where the flame height and candle consistency are observed and recorded. The preferred embodiment exhibited a 1" flame height throughout repeated 4 hour burn segments with no distortion of the molten pool as per the ASTM F2417-04 protocol until the entire candle was consumed which would be classified as a clean burn to completion.

[0074] EXAMPLES

[0075] A repellency test that may be used to examine efficacy of the wax-based delivery systems of embodiments of the invention is outlined as follows: a laboratory trial was conducted to evaluate the repellency of a pyrethrum candle against female Aedes aegypti mosquitoes. One lit candle was placed on one side of a divided chamber, and 250 female Aedes aegypti mosquitoes were released on the other side of the chamber. The mosquitoes were allowed to distribute for 2 hours, while a CDC light trap baited with dry ice ran on the side of the chamber with the candle. The number of captured mosquitoes was then counted. Both treated and untreated candles (pyrethrum wax and without pyrethrum wax) were assessed. In one test, a blank candle without Pyrethrum wax had no repellency while the Pyrethrum wax candle prepared according to Example 4, below, exhibited 91.7% repellency +/- 8.3%.

[0076] The following examples are exemplary only and should not be construed as limiting of the embodiments as they are encompassed by the claims.

[0077] Example 1 : 55.00% Paraffin Wax + 20.00% Beeswax + 5.00% Microcrystalline Wax + 10.00% Pyrethrum Wax + 10.00% Isopar™ M (Exxon: CI 1-C16 isoalkane hydrocarbon).

[0078] Example 2: 25.00% Partially Hydrogenated Wax SP1267 (Strahl & Pitsch) + 28.00% Paraffin Wax + 20.00% Beeswax + 5.00% Microcrystalline Wax + 2.00% Vybar 260 (Baker Hughes: Hyperbranched polyolefin) + 10.00% Pyrethrum Wax + 10.00% Isopar™ M

(Exxon: CI 1-C16 isoalkane hydrocarbon). More information on Partially Hydrogenated Wax SP1267 may be found, for example, in the July 9, 2009 Strahl & Pitsch's Material Safety Data Sheet for SP-1267, which is incorporated by reference herein. SP-1267 comprises hydrogenated soybean oil.

[0079] Example 3 : 52.80% Paraffin Wax + 25.00% Stearic Acid + 0.20% Tenox TBHQ (Eastman Chemical: Tertiary butyl hydoquinone) + 2.00% Pyrethrum Concentrate (50% activity) + 10.00% Pyrethrum Wax + 10.00% Isopar™ M (Exxon: CI 1-C16 isoalkane hydrocarbon). More information on Tenox TBHQ may be found, for example, in the October 31, 2008 Eastman's Product Data Sheet for Eastman Tenox TBHQ, which is incorporated by reference herein.

[0080] Method of candle preparation:

[0081] Premix pyrethrum wax and Isopar™ M in a secondary vessel and heat to 50°C until a uniform liquid is obtained. Stir occasionally to ensure that all material has melted and dissolved in the hydrocarbon solvent. Hold the temperature at 50°C until ready to add to the candle wax base. In the main mixing vessel add the paraffin wax and stearic acid. Heat the 2 materials to 75°C until they melt and form a clear molten liquid. Add the pyrethrum wax / Isopar blend to the molten wax mixture in the main kettle maintaining a temperature of 60°C. The resulting mixture will turn a dark opaque brown color. Mix until a uniform liquid wax blend is obtained. Add the TBHQ and Pyrethrum Concentrate to the main vessel and continue mixing for 5 minutes at 60°C until all is uniform. Pour liquid mass into suitably sized containers and carefully place a CDN 8 wick in the center of the container. CDN series wicks (Southwest Candle Supply Company) are a coreless, no directional, flat braided wick with a cotton & paper filament woven around it. Allow the mass to cool and set up as a solid wax matrix.

[0082] Examples:

[0083] Example I: A wax-based delivery system comprising: pyrethrum wax; and a

hydrocarbon solvent comprising light petroleum distillates of C7-C16 hydrocarbons, wherein the pyrethrum wax and the hydrocarbon solvent are present in the system by weight in a ratio of pyrethrum wax to hydrocarbon solvent between 40:60 and 60:40.

[0084] Example II: The wax -based delivery system of Example I, wherein the ratio of

pyrethrum wax to hydrocarbon solvent is about 50:50.

[0085] Example III: The wax-based delivery system of any of Examples I-II, further

comprising a second wax, an antioxidant, a stabilizer, and a co-solvent.

[0086] Example IV: The wax-based delivery system of any of Examples I-III, further

comprising at least one member of the group consisting of a pure pyrethrum, pyrethroids synergist, a carbamate-based enzyme inhibitor, a pyredine-based growth inhibitor, and a peroxide scavenger.

[0087] Example V: The wax -based delivery system of any of Examples I- IV, wherein the system is a candle and wherein the pyrethrum wax is present in an amount of from 1-10% of the system.

[0088] Example VI: The wax-based delivery system of any of Examples I-V, wherein the active ingredient level of pyrethrum is maintained by the addition of pyrethrum in the amount from 0.1 - 2%.

[0089] Example VII: The wax -based delivery system of Examples I- VI, wherein the

pyrethrum is pyrethrin.

[0090] Example VIII: The wax-based delivery system of any of Examples I- VII, said system comprising paraffin wax in an amount between 2% and 90% by weight of the system. [0091] Example IX: The wax -based delivery system of any of Examples I- VIII, wherein the hydrocarbon solvent comprises at least one solvent selected from the group consisting of C11-C16 isoalkane hydrocarbons and mineral spirits.

[0092] Example X: The wax -based delivery system of any of Examples I- IX, wherein the system comprises at least 1% by weight of at least one pyrethrin.

[0093] Examples XI: The wax -based delivery system of any of Examples I-X, further

comprising a wick, wherein the wick comprises a cotton flat braided wick and a paper filament, wherein the paper filament is crisscrossed on the outside of the cotton flat braided wick, and wherein the wick is treated with a high temperature melting wick wax.

[0094] Example XII: The wax -based delivery system of any of Examples I-XI, further

comprising a wick, wherein the wick is a bleached, loose square braided wick consisting of cotton that is treated with a high temperature melting wick wax.

[0095] Example XIII: The wax-based delivery system of any of Examples I-XII, further comprising a heater plate.

[0096] Example XIV: A method for repelling insects, comprising: heating a wax -based

delivery system of any of Examples I-X and XIII.

[0097] Example XV: The method of Example XIV, wherein said wax -based delivery system is heated in a wax warmer for a period of 1-8 hours at a constant temperature between 45°C - 80°C until the solid wax blend has melted thereby releasing the active pyrethrum into the environment.

[0098] Example XVI: A method for preparing a pyrethrum wax -based delivery system, comprising: mixing pyrethrum wax and hydrocarbon solvent comprising a mixture of CI 1- C16 isoalkane hydrocarbons, wherein the pyrethrum wax and the hydrocarbon solvent is present in the system by weight in a ratio of pyrethrum wax to hydrocarbon solvent between 40:60 and 60:40 pyrethrum wax to hydrocarbon solvent; adding the mixture of pyrethrum wax and hydrocarbon solvent to a molten wax selected from the group consisting of paraffin wax and saturated fatty acid; and cooling the mixture.

[0099] Example XVII: The method of Example XVI, wherein the pyrethrum wax is

dissolved in a hydrocarbon solvent at 50°C and added to a molten mixture of paraffin wax and fatty acid at 75°C followed by addition of a peroxide scavenger and pure pyrethrum, mixed until uniform and poured into a container.

[0100] Example XVIII The method of any Examples XVI-XVII, wherein the mixture is cooled around a wick.

[0101] Example XIX: The method of Example XVIII, wherein the wick comprises a cotton flat braided wick and a paper filament, wherein the paper filament is crisscrossed on the outside of the cotton flat braided wick, and wherein the wick is treated with a high temperature melting wick wax.

[0102] Example XX: The method of Example XVIII, wherein the wick is a bleached, loose square braided wick consisting of cotton that is treated with a high temperature melting wick wax.

[0103] Those skilled in the art will appreciate that the above disclosure reports preferred embodiments, but that the scope of the invention is sufficient to cover all of those embodiments encompassed by the claims.