Background This invention relates to combustible products that emanate an insecticide into the atmosphere on combustion and more particularly to such products that undergo combustion for a prolonged period thereby providing an extended time period of insecticide activity. There are several different types of insecticide products that rely only on combustion as a source of energy to be effective.

The most commonly used of these are commonly referred to as "mosquito coils" or even more simply as "coils". Typically, mosquito coils are used in environments where persons sleep and are therefore unable to destroy mosquitoes before being bitten. Another usage is environments where infants or others incapable or having a limited ability of destroying attacking mosquitoes are placed.

It will be readily appreciated that mosquitoes are vectors for a number of particularly persistent and often life-threatening or at least debilitating diseases.

Most significant among these diseases is malaria. It is therefore highly desirable to prevent mosquito bites as a means of preventing the contracting of such diseases. Mosquitoes are particularly prevalent in tropical and sub-tropical regions.

Many of these regions include countries with relatively low per capita incomes. It is therefore desirable to be able to provide insecticidal products that are highly cost effective.

In general terms, traditional mosquito coils fulfil this role. They are relatively easy to form and include low cost ingredients. As emanation of the insecticide is only dependant on combustion of the coil, the only source of energy required is sufficient heat to initially ignite a coil to cause it to combust. Coils have a number of drawbacks however. They are often brittle and suffer breakage. They often produce a great deal of smoke along with the heat needed to volatilise the insecticide. Also once broken, the coil will cease to burn and protection from mosquitos will cease. This is particularly a problem when protection is sought overnight.

Another popular combustible insecticide product format are paper based. An example is Mortein Activcard. These products consist of a paper sheet impregnated with an insecticide active and a smouldering agent. These products are cheap to produce and can be highly effective. They are consumed in a smouldering flame within a 3 minutes and can provide protection for an average size room for 4 hours.

The paper products have a number of drawbacks however. They are extremely light and can be blown very easily around when lit causing a fire hazard. They also suffer from a believability gap. Many consumers simply do not believe the product continues to work for long once the paper has ceased burning.

WO 01/43542 A1 discloses rope like insecticide products. These over distinct advantages over the coil and paper sheet products described above. These rope-like products are not without their disadvantages however. The disclosure of WO 01/43542 A1 are incorporated by reference.

It is the aim of the present invention to obviate some of the problems associated generally with combustible insecticide products. In particular the present invention describes a combustible insecticide product that attempts to overcome some of the problems inherent with those of the currently available products, particularly the ropes of WO 01/435.

Statements of invention

According to the present invention there is provided an insecticide product

comprising a combustible support; an active insecticide, and a smouldering agent; wherein the combustible support comprises a self-supporting rope formed of at least one strand of rolled paper; and wherein the rope has a width of between 2 and 25 mm. In a further embodiment the rope has a width between 4 and 8 mm.

In a further embodiment the rope has a weight of between 1 and 500 grams per metre, preferably between 1 and 100 grams per metre and most preferably between 25 grams per metre.

In a further embodiment the rope has an essentially circular cross section.

In a further embodiment wherein the rope comprises two strands, the rope has an essentially helical cross section.

In a further embodiment the paper used to form the rolled strands may have a basis weight of between 20 and 300 gsm, preferably between 25 and 120 gsm more preferably a basis weight between 30 and 100 gsm and most preferably between 35 and 70 gsm.

In a further embodiment the product comprises two or more active insecticides.

In a further embodiment the active insecticide comprises a pyrethroid. In a further embodiment the active insecticide comprises between 0.001 and 20 % by weight of the insecticide product.

In a further embodiment the active insecticide preferably comprises between 0.005 and 5 % by weight of the insecticide product.

In a further embodiment the smouldering agent comprises potassium nitrate.

In a further embodiment the potassium nitrate comprises between 0.01 and 10% by weight of the insecticide product. In a further aspect of the present invention there is provided a method of making the products of the present invention comprising steps of;

1 ) Treating a sheet of paper with a solution comprising at least one

insecticide active and a smouldering agent

2) Drying the paper sheet.

3) Rolling the paper into a strand of between 2.5 and 12 mm thick.

4) Cutting the strands into desired lengths

In a further embodiment two or more of the strands are wound or twisted together to form a rope.

In a further aspect of the present invention, the use of an insecticide product of the present invention to kill insects in an internal space wherein the product is lit at one end and allowed to burn slowly along its length. Brief description of the Figure

Figure 1 shows an embodiment of the present invention. The rope depicted is formed from two twisted strands of rolled paper. One of the strands has been dyed. Figure 2 shows the rope of Figure 1 viewed from above or below.

Figure 3 shows an alternative embodiment to that depicted in Figure 1. The rope is also formed from two strands of rolled paper. Neither of the strands has been dyed. Figure 4 shows the rope of Figure 3 viewed from above or below.

Detailed description of the Invention

The product of the invention is a combustible rope. The rope is made of at least one strand of rolled paper. Preferably the rope is prepared from two or more strands of rolled paper that may be twisted or braided together. The rope may be prepared from three of more strands woven or braided together. The ropes are self-supporting and may remain substantially upright even if held at their base.

The rope may have a thickness of between 3 and 15 mm, preferably between 4 and 12 mm and most preferably between 5 and 8 mm.

In embodiments wherein the ropes are made from a single strand the strand will also have a thickness of between 3 and 15 mm, preferably between 4 and 12 mm and most preferably between 5 and 8 mm.

In embodiments wherein the ropes are made from two or more strands of rolled paper that are twisted or braided together the strands may have a thickness between 2.5 and 12 mm, preferably between 3 and 8 mm and most preferably between 4 and 6 mm. The thickness of the paper used to form the rolled strand plays a part in the length of paper required to form strands of defined thicknesses. Without wishing to be bound by theory, this also provides an opportunity to adjust burning rates and consistency of burning. The length and thickness of the rope provided will depend on the burning time required and may be adjusted for this purpose.

Preferably the ropes will be provided in lengths between 12 cm and 40 cm, more preferably between 15 cm and 30 cm and most preferably between 20 cm and 30 cm.

It is possible that different lengths may be provided for the user to select protection time required. It may be that the rope may be provided in a single long coil and the user will cut the rope to the desired lengths before use. The rope products may have a weight of between 1 and 500 grams per metre. Preferably the rope products may have a weight of between 1 and 150 grams per metre, more preferably between 2 and 50 grams per metre and most preferably between 5 and 20 grams per metre. The rope has the advantage over coils of being flexible and not prone to breakage. (Coils are most often moulded products). The rope has the advantage over paper sheet products of being more substantial and less likely to be blown away. Also the rope will smoulder for much longer that a paper product and will provide the user with more reassurance that it is working.

Another further advantage of the ropes is low ash generation on burning, and are therefore much less messy.

The paper maybe of any type suitable for rolling into a rope form. The thinner and stronger the paper the more flexible the rope will be. The thicker the paper the more stiff the final rope will be. Thicker paper will yield rope products that are stick like in appearance and strength.

The paper used to make the rope products of the present invention may have a basis weight of between 20 and 300 gsm. Preferably a basis weight between 25 and 120 gsm more preferably a basis weight between 30 and 100 gsm and most preferably a basis weight of between 35 and 70 gsm.

Generally, thinner papers are easier to roll into the required thicknesses of strands and will be preferred. The paper may be formed from any fibre source known in the art. Particularly preferred fibre sources are wood pulp and cotton.

The paper used in the present invention may be recycled paper. The paper used in the present invention may also be unbleached.

One of the disadvantages of the rope products in the art is the inconsistency of burning time. One of the advantages of the ropes of the present invention is the finding that rolled paper strands provide a remarkably consistent burning rate. Without wishing to be bound by theory it is believed by the applicant that air trapped within the rolls of the strand allows for consistent and even burning.

The burning time of the rope will be dependent on a range of factors, the paper material chosen for the strands, the density of the rope, the thickness of the rope, the quantity of flame limiting chemicals and the length of the rope. The present invention therefore gives the skilled person the possibility of fine tuning the burning time in a number of ways. The rope products of the present invention will preferably have a burning time of between 10 mins and 6 hours. Preferably the ropes of the present invention will have a burning time of between 20 min and 4 hours and most preferably the ropes of the present invention will have a burning time of between 30 min and 2 hours. It is preferred that the rope products of the present invention provide effective insecticide performance for at least 4 hours from initial combustion. Preferably the rope products provide effective insecticide performance for at least five, more preferably at least six hours. The rope products of the present invention preferably give off very low quantities of smoke when burning.

The rope products may be burned from any surface. They may require a stand if in stick shape, for other shapes stands may or may not be required.

The rope products of the present invention also gives the skilled person and end user greater flexibility in choice of aesthetic form than either a coil or a single sheet of paper. Each rope may be twisted into many different shapes. Or made stiff and stick like. The cross section of the ropes may form any shape desired. The preferred shape is a circular cross section, or helical if two or more strands are used to form the rope.

If two or more strands of rolled paper are used to construct the ropes of the present invention then one or more strands may be provided without actives ingredients and used only as a support. Alternatively each strand may have a similar amount of active ingredients.

If two or more strands are used to form the ropes of the present invention. The two or more strands may be formed from identical sheets of rolled paper. Or alternatively the two or more strands may be formed of different types of paper. This may be such that one of the strands is stronger and stiffer and used to provide support to a lighter and more flexible strand. The insecticide products of the present invention require an active insecticide substance.

The products may comprise a single active substance or a mixture of two or more insecticide actives.

The insecticide products of the present invention preferably have an active insecticide substance selected from the group consisting of the pyrethroids, in particular selected from the group consisting of acrinathrin, allethrin, d-allethrin, d-frans-allethrin, d-c/s- trans-allethrin,alphamethrin, bathrin, bifenthrin, bioallethrin, S-bioallethrin, bioallethrin S-cyclopentyl isomer, bioethanomethrin, biopermethrin, bioresmethrin, clocythrin, chlovaporthrin, cycloprothrin, cyfluthrin, beta-cyfluthrin, cyhalothrin, gamma- cyhalothrin, lambda-cyhalothrin, cypermethrin, alphacypermethrin, beta-cypermethrin, cis-cypermethrin, theta-cypermethrin, zeta-cypermethrin, cyphenotrin, deltamethrin, depallethrin, empenthrin, empenthrin (1 R isomer), esbiothrin, esfenvalerate, etophenprox, fenfluthrin, fenpropathrin, fenpyrithrin, fenvalerate, flubrocythrinate, flucythrinate, flumethrin, fubfenprox, imiprothrin, kadethrin, metofluthrin, neopynamine, permethrin, cispermethrin, trans-permethrin, phenothrin, phenothrin (IR-trans isomer), d-phenothrin, prallethrin, profluthrin, protrifenbute, pynamin forte, pyresmethrin, pyrethrin, resmethrin, cis-resmethrin, silafluofen, tau-fluvalinate, tefluthrin, tetramethrin (phthalthrin), tetramethrin (1 R isomer), terallethrin, tralomethrin, transfluthrin, metofluthrin, pyrethrins (pyrethrum) and any mixture of the abovementioned substances.

Particularly preferred actives include transfluthrin, metofluthrin and biothrin. A mixture of both natural and manmade insecticide substances may be used. Examples of natural insecticide substances include citronella and neem. The insecticide product may include the active insecticide between 0.001 and 20% by weight of the final rope product. Preferably the active will be between 0.005 and 5% by weight of the final rope product. The skilled person will be able to determine the precise loading required for effective insect control based on the performance of the active selected for use and the required potency.

When using a synthetic pyrethroid insecticide such as transfluthrin or metofluthrin the loading of active typically will be between 0.1 mg and 5 mgs per hour of burning. Preferably between 0.2 and 3mgs per hour of burning and more preferably between 0.5 and 2 mgs per hour of burning time.

The active ingredients may be provided to the surface of the rope by any method known in the art, including by not limited to painting, spraying, coating, dipping or printing etc.

In a preferred method of manufacture, the active ingredients (and optional ingredients if desired) may also have been applied to the paper prior to rolling into strand or strands. The paper maybe coated or soaked in the active prior to rolling into a rope form. The active agents are dissolved in a suitable solvent prior to contacting with the paper.

The solvent is then removed and the papers are rolled into strands and cut into desired lengths. Two or more strands may then be woven, braided or twisted together to form a rope product, if desired.

In embodiments where the paper is treated prior to rolling into strands provides further advantages over the ropes of the art. The paper strands provide for an even distribution of actives and other chemicals throughout the interior of the rope. This helps to protect the concentration of active during product storage by minimising loss by leakage and evaporation from the rope surface. The product of the present invention comprises a smouldering agent to reduce flame production on burning.

Potential smouldering agents include alkali or alkaline earth metal nitrates or nitrites, or an alkali or alkaline earth carbonate or bicarbonate.

Preferably the smouldering agent used will be an alkali or alkaline metal nitrite or nitrate. The most preferable smouldering agent is potassium nitrate.

Preferably the smouldering agent comprises between 0.01 and 30% by weight of the insecticide rope product, more preferably between 0.02 and 10% and most preferably between 0.03 and 5% by weight. The skilled person will be able to fine tune this value based on the burning time desired.

Like the insecticide component above. The smouldering agent may be applied to the surface of the finished rope or applied to the materials used to form the rope.

The product of the present invention may comprise further ingredients such as dyes, pigments _^ perfumes, preservatives, binding agents, etc. The nitrates or nitrites that may be used include sodium, potassium, calcium, magnesium salts and mixtures thereof. It is preferred to utilise potassium as the nitrate or nitrite counter ion.

These may be included for technical as well as aesthetic reasons. Perfumes may render the rope product desirable as both an air treatment product as well as an insecticide product.

If dyes or perfumes are used then each strand of paper forming the rope may be dyed or perfumed independently. Optional ingredients may be present in the quantity needed for effective performance. This may be between 0 and 15 % of the weight of the final rope product. The products of the present invention may be used to control or kill insects. Preferably this occurs in an internal space. The products are lit at one end and allowed to burn slowly along their length.

The product may be supported by a dedicated stand during burning.

Preferred examples of the present invention:

In a particularly preferred embodiments the insecticide ropes would be comprised of two strands of rolled paper twisted together, be between 16 and 25 cm long with a total width of between 4 and 7 mm. Individual rolled paper strand widths are preferably between 2 and 4 mm. One or both strands of rolled paper forming the rope may be dyed. One or both strands of the ropes may contain the active insecticide ingredient. The total burning time for these ropes would be approximately 30 min -1 hour. The preferred insecticide active would be transfluthrin and the preferred smouldering agent would be potassium nitrate.

Experimental results

Ropes according to the preferred examples above were prepared and tested for effect against mosquitos in standard lab conditions. The ropes provided excellent knock down and mortality scores while their burning rate was consistent across the entire length.