A Method Of Manufacturing Mosquito Repellent Coils

Abstract

A method of manufacturing mosquito coils consisting of cutting strings of natural fibre material of predetermined length; preparing a plastic dough or slurry containing a homogenous mixture of a pyrethroid as the active ingredient, a smoldering agent, a binder, an ernulsifier and combustible fillers; dipping the strings in the dough or slurry until the strings are saturated with the dough; squeezing out any excess dough from the strings; coiling the dough laden strings into a desired shape and drying the coiled dough laden string to form the mosquito coil of this invention.

Information

Applicants

Inventors

Specification

FORM -3A
THE PATENTS ACT, 1970
COMPLETE
SPECIFICATION
SECTION 10

TITLE

A METHOD OF MANUFACTURING MOSQUITO REPELLENT COILS

APPLICANT

GODREJ SARA LEE LIMITED, PIROJSHANAGAR, EASTERN EXPRESS HIGHWAY, VIKHROLI (EAST), MUMBAI 400 079, MAHARASHTRA, INDIA

The following Specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed:-

Field of invention
The present invention provides novel synergistic composition and device for combating insects such as mosquitoes.
Particularly, the present invention relates to a mosquito repelling coil and a process of manufacturing a mosquito coil used to kill/repel flying insects.
The present invention relates to mosquito coils and other burnable insect control ingredient delivery devices. More particularly, it provides breakage resistant fumigants that deliver an insect control ingredient
Background of the mvention
Compositions usually in the form of pesticidal compositions such as solutions, emulsion, aerosol sprays and preferably in the form of a fumigant wherein the active ingredient is vaporized for combating insects, particularly mosquitoes are known. One such form has the non-active part of the fumigant as a combustible insecticidal serpentine or coil and another form has the non-active part of the fumigant as an incombustible mat substrate and after incorporation of the active ingredient, the fumigant is put in a heating apparatus such as an electric mosquito destroyer whereby the active ingredients may be vaporized at will for prolonged periods of time.
In the case of serpentine or coil insecticides, the inert combustible support material may be made of pyrethrum residue, Tabu powder (or powder of Machilus Thumbergii leaves), pyrethrum stalk powder, powder of cedar-tree
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leaves, sawdust such as pine sawdust, starch and shells powders such as,
powdered coconut shells. ,
The compositions may also be prepared in the form of a sprayable oil as a base for the active composition in which the oil is used impregnate the wick of a lamp and which is capable of burning to vaporize the active compositions.
The compositions may also be in the form of aerosol sprays by incorporating the active composition into the necessary adjuvants or in any other suitable form to diffuse the active composition.
The compositions can also have incorporated therein other usual ingredients such as stabilizers such as phenols and arylamines, classical synergists of pyrethrinoids such as l-(2,5,8-tnoxadodecyl-2-propyl-4,5-methylenedioxy)-benzene or piperonyl butoxide, N-(2-ethyl-heptyl)-bicyclo-[2,2,l]-5-hepten-2,3-dicarboximide and piperonyl-bis-2-(2'-n-butoxyethoxy)-ethyl acetal or Tropital, antioxidants such as tocopherol acetate or emulsifying agents.
The compositions of the invention may be used in the home to destroy insects such as houseflies, mosquitoes, etc. and in industrial locations for destroying, for example, insect pests for cereal crops and insect pests for horticulture. The compositions may also be used in the veterinary field to combat sarcoptides and ixodides, especially gales and ticks. In the latter field, the active compositions and the other additions are generally used in solution in an alcohol or mixture of alcohols.
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This invention particularly relates to a mosquito coil in the form „of a spital or
serpentine.
Mosquito coils are coils of slowly burnable solid material that contain an insect control ingredient such as a repellent, an insecticide, or an insect growth regulator. When they burn, heat vaporizes (and thereby disperses) the insect control ingredient. Small amounts of smoke also help to disperse the insect control ingredient.
Mosquito coils have been used for a quite long time to drive away mosquitoes and other flying insects. These coils contain solid burnable materials that are combined with insecticides, repellents and insect growth regulating substances and released along with the smoke. When they burn, heat vaporizes the active ingredient from few inches away from the burning tip thereby dispersing the insecticides. Traditional mosquito coil compositions is prepared having 25% or more of pyrethrum residue from pyrethrum extract known as pyrethrum marc, as it is thought this material is a necessary ingredient to produce an acceptable mosquito coil. In addition to the pyrethrum marc, the prime burning agent or fuel used for mosquito coils is coconut shell flour, tabu powder, sawdust, ground leaves, ground bark, starch etc. US patent numbers 3248287, 3723615, and 3819823 [no Indian equivalent available] describe the process of preparing mosquito coils. The latter two patents describe the use of various carrier agents such as wood powder and starch.
US patent No. 5447713[ no Indian equivalent available] discloses, a mosquito coil having a conventional spiral configuration, and US patent No.
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¥ '':■ f
3754861 [no Indian equivalent available] describes a mosquito coil, having a match like ignition tip containing potassium chloridel as an oxidizer.;"'!'-Mosquito coils are also known as solid fumigants and are described in US .?' patent No. 4296091 [no Indian equivalent available] in different shapes. US patent 5447713 [ no Indian equivalent available] describes a process for producing mosquito coils from wood chip or wood fiber material of a density of 0.4-0.7kg/dm3 that are resistant to breakage, light flat and ensure good active substance yield. In Japanese patents 7 8027-341 [ no Indian equivalent available] explains the process of preparing coils from a doughy composition of fibrous waste, such as rayon waste, cotton waste, waste paper or else wood fibers and mineral fibers, binders and active substance as well as if appropriate, further additives, dry them and punch out coils.
Various compositions for preparing mosquito coils are known. For example, US Pat No. 4144318 [no Indian equivalent available] teaches the use of allethrin, tabu powder, starches, wood powder, cocoshell powder, and dye in mosquito coils, and US patent No. 4296091 [no Indian equivalent available] discloses the use of a perfume in a mosquito coil. US patent No. 5657574 [no Indian equivalent available] describes coil having an enlarged outer portion for providing quick coverage of an insect control ingredient in a space that previously had none. It also provides greater breakage resistant by addition of urea and improves igniting and burning characteristics by adding kerosene and peanut shell powder.
In the prior art process therefore the mosquito coil is punched out from a board consisting of wood-chip and/or wood-fibre material and is provided with an active substance, and in the process for producing mosquito coils,
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wood chips and/or wood fibres are pressed, with binders 'if appropriate, to. form boards and the coils are punched out therefrom. These barks are of 4 to *
' , X "I
6 mm thickness from a doughy composition of fibrous waste, such as rayon ' waste, cotton waste, waste paper or else wood fibres and mineral fibres, binders and active substance as well as, if appropriate, further additives, to dry them and punch out coils therefrom are also used. Such a board material has in the dried state a relatively high density. The flexural load-bearing capacity of the coils punched out therefrom is low, so that breakage readily occurs during handling. Owing to the high density, the boards dry only slowly and often warp during drying. The high material density also makes the product expensive. The high density also causes problems during punching-out of the coils, because the cutting edge of the spiral punching cutter is often bent, so that an unclean cut is produced and the coil jams between. the turns of the punching cutter because the restoring force of an insert of flexible foam, serving as ejector, is no longer adequate.
Since the active substance is distributed uniformly in the composition, during burning of the coil only about half the active substance is released into the open, whereas the remainder oxidizes beforehand and becomes ineffective in an undesired way.
The drawbacks of these prior art mosquito coils therefore are that (1) the wide variability in the raw materials used such as sawdust, coconut shell powder lead to process and product variations; (2) enormous requirement of energy in the drying process; (3) coils warp during drying process; (4) prone to breakage during usage thus making it inconvenient to the users; (5)
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• /••' . '*'',"■■
difficult in separation of two spiral coils during usage. (6) Difficulty in
extinguishing when not in use.
The object is to provide a mosquito coil which is more resistant to breakage, is lighter and can be configured into any desirable shape and length, ensures a higher efficiency of the active substance and can be produced without any problems.
Hence it is an object of the present invention to produce mosquito coils that are made of natural fibers as burning material and can be configured in a serpentine form as a flat spiral or as a helix.
It is also an object of the present invention to produce mosquito coils that are very cheap and use natural fibers like jute, coconut, cotton etc. as burning substrate materials to release the insecticide active ingredient thus avoiding usage of excessive raw materials.
It is also an object of the present invention to produce mosquito coils that avoids the problem of breakage during transport and usage and also ease in handling.
It is also an object of the present invention to produce mosquito coils having natural fibers strings as substrate burning materials that avoids cumbersome processing of kneading, extruding and stamping through molds used in preparation of conventional coils.
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Detailed description of the Invention:
The present invention describes a process of making a coiled insect fumigant from pyrethro ids made of natural fibers and is used to kill/fepe1 fling insects.
More particularly the present invention describes a method of manufacturing a mosquito coil that uses strings of natural fibers more particularly from plant fibers like jute, coconut, sisal, and cotton and the like, as a substrate burning material and having pyrethro ids as the active ingredient.
According to this invention there is provided a method of manufacturing mosquito repellent coils consisting of cutting strings of natural fibre material of predetermined length; preparing aplastic dough containing a homogenous mixture of a pyrethro id as the active ingredient, a smoldering agent, a binder, an emulsifier and combustible fillers; dipping the strings in the dough until the strings are saturated with the dough; squeezing out any excess dough from the strings; coiling the dough laden strings into a desired shape and drying the coiled dough laden string to form the mosquito coil of this invention.
In accordance with a preferred embodiment of the invention the method of manufacturing mosquito coils in this invention includes strings are of jute fibres, the active ingredient is 0.4 to 0.5% of the dough or slurry, the smoldering agent is 0.2 to 0.3% ; the binder is 7 to 8%; the combustible fillers are 85 to 90%, the emulsifier is 0.2 to 0.4 % of the total weight of the dough or slurry.
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The strings are typically provided with an eye at one end before dipping for attaching the coil to a suitable fixture in its operative configuration.
In accordance with this invention preferably perfume, preservative and a coloring agent is added to the dough or slurry.
Typically, the present invention describes a process for preparing mosquito coil from natural fibers that contains pyrethroid as the active ingredient 0.45% w/w, 0.35% w/w potassium nitrate as the smoldering agent, 8% w/w guar gum as binder, 44.45 w/w% each sawdust and coconut shell powder as fillers, 0.3% w/w malachite green as color giving agent, 1% w/w jasmine perfume, 0.4% w/w unitox emulsifiers and 06% sodium benzoate as preservative and these ingredients are loaded to 3ply jute fibers and wound to form a coil for burning to repel mosquitoes for more than 6hrs.
The mosquito coils according to the present invention can be prepared by employing the following method.
Firstly the active ingredient is weighed to the required quantity in a glass beaker and to this added the required quantity of emulsifier Unitox and stirred well for 15-20 mts. using a magnetic stirrer at 3000-5000rpm. To this mixture A jasmine perfume is added and stirred well for 5mts. Required quantity of water is added then to the mixture and stirred well for another 20mts. Separately required quantities of potassium nitrate and dye is weighed and mixed. To this water is added and the resultant mixture B is mixed with the mixture A to form mixture C and kept ready for preparation of the dough.
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The dough is prepared by weighing the fillers, coconut shell powder, and sawdust powder. To this powder the above mixture C is added and kneaded to yield dough of desired consistency. Strings of jute measuring approximately 200cms length and 3g weigh and having a thickness of 1.5-15mm thickness is cut and dipped in the dough for 15 mts for complete absorption. After 15mts, the strings are removed from the dough and the excess formulations are squeezed out of the string by just pulling the strings from in between the fingers tightly. The strings that have absorbed the formulations are wound on to a pipe or cylindrical cardboard rod to form a helical coil having internal diameter of 20-25mm. Blow-drying or hot air drying in an oven at 65oC for 30-lhrs dries these coils, and removed to form helical coil. The above helical coil prepared have a burning time of >6hrs. It is also possible to increase the burning time to 8hrs or 10 hrs. by altering or increasing the string length to give the desired burning time.
To manufacture the preferred coil, one can use several methods. One such method is to prepare the inert materials along with the active ingredients and make it in the form of slurry instead of kneading. The strings are dipped in the slurry for 15-20mts. and the steps for preparing the helical coil is made according to the same procedure as described above.
Unlike the solid burnable materials like wood powder that are used in conventional coil manufacturing, the present invention uses strings of natural fibres from plants like jute, and could be also from coconut, sisal, and cotton and the like.
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The wood powders namely coconut shell powder, sawdust powder could also be added along the dough and applied to the strings and used as combustible; fillers.
The strings of natural fibers according to the present invention contains jute and could also be selected from coconut, sisal, cellulose fibers, cotton, linen, hemp, ramie, jute, rayon, viscose rayon, cuprammonium rayon, Acetate rayon, and protein fibers lime wool, silk and mixtures thereof.
The active insecticide ingredient used in the present invention is selected from pyrethroids and more particularly allethrin. Preferred pyrethroids also include resmethrin, bioallethrin, allethrin, and mixtures thereof. Other insect controlling ingredients can be used such as the repellents, citronella, lemongrass oil, lavender oil, cinnamon oil, neem oil, clove oil, sandal wood oil, eucalyptus oil, basil oil, calamus oil, and mixtures thereof
Other substances, which can furthermore be added to the formulations according to the invention, are natural perfumes such as for example musk, cibet, ambergis, almond oil rosewood oil, cajeput oil, cananga oil, capsicum oil, caraway oil, cardamon oil. Carrot seed oil, cassia oil, cedar wood oil celery seed oil, cinnamon bark oil, citronella oil celary, sage oil, clove oil, cognac oil coriander koil, cubeb oil, camphor oil, dill oil, taragon oil, sweet fennel oil, galbanum resinoid, garlic oil, geranium oil, ginger oil, grapefruit oil, hop oil, absolute of hyacinth, absolute of jasmin, juniper berry oil, labdanum resinoid, lavender oil, bay leaf oil, lemon oil, lemongrass oil, lovage oil, mace oil, mandarin oil, absolute of mimosa, absolute of myrrh, mustard oil, absolute of narcissus, neroli oil, bitter orange, nutmeg oil
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absolute of mimosa, olibanum resinoid, onion oil, oponax resinoid, orange oil, concrete iris, pepper oil, peppermint oil, Perubalsam, petirgrain oil, pine needle oil, absolute of rose oil, sage oil, spearmint oil, storax oil, thyme oil, balsa of tolu, absolute of vanilla, pod, vetiver oil, absolute of violet leaves and mixtures thereof.
The coiled insect fumigant according to the present invention may also incorporate various burning aids which assist in sustaining the burning of the coil. Traditional and conventional burning aids can be utilized such as sodium and potassium nitrate, and mixtures thereof.
The colorants which can added to for the appearance can be selected from malachite green, amaranth dye, alizaryn dye stuffs, azo dye stuffs, and metal phthalocyanine dyestuffs, and trace nutrients such as salts of iron, manganese, boron, copper, cobalt, molybdenum and zinc.
The coil of the present invention is used to repel and/or kill flying insects which may be present in living quarters or other selected enclosed or open spaces.
The following example explains the invention in detail and it should be understood that this invention is by no means limited by these examples.
A typical formulation recipe according to the present invention has the following ingredients.
Wt % (w/w)
1. d-trans allethrin (active) 0.009g 0.45
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2. Potassium nitrate (burning aids) 0.006g 0.30
3. Guar gum (binder) 0.16g 8.0,
4. Saw dust (filler) 0.896g 4448
5. Coconut shell powder (Filler) 0.896g 44.48
6. Malachite green (color) 0.006g 0.3
7. Jasmine perfume 0.02g 1.0
8. Unitox 3A4 (emulsifier) 0.008g 0.4
9. Sodium benzoate 0.01.2g 0.6
(Preservative)
The formulation is prepared for 3 grams. The active ingredient, emulsifiers and perfume are weighed in a glass beaker and to this required quantity of water is added to the weighed material and stirred properly in a stirrer for 30 mins. In a separate beaker, potassium nitrate and dye is weighed and mixed. To this water is added and stirred well for 15 mins. in a Remi magnetic stirrer. Now the solution is mixed well with the above-prepared solution and prepared in the form of dough. A jute strings of 3ply 200 cm length is taken and soaked in the above prepared dough in a plastic basin for 15-30mins. After 15 mins., the string is removed from the dough and the extra formulation adhering to the string is removed by just pulling the strings from in between the five fingers . The impregnated string with the formulation is wound on paper or on a hollow cylindrical board or a pipe to give a helical structure. These strings are dried in an oven at 65°C approximately for 6hrs. The final product appears like a helical coil with a internal diameter of 1.5-5 cms and can be burned by igniting the tip with a match box and used in a closed room or open area to drive the mosquitoes/flying insects away.
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In another alternate method to the same formulation initially lOg of tapioca starch and 0.3g of potassium nitrate is cooked with 50 ml of water and kept separately. To this solution, guar gum 2% solution is added to the above solution by constant stirring in a stirrer at 20,000-30,000rpm for 30 min. These materials along with the active ingredient is transferred in a trough and the string is immersed for 15 min. and wound in a cylindrical structure to get helical coiled insect fumigant. The coil weighs about 5-6gms and measuring 200cm in length intended to burn for 6hrs continuously.
Various modifications of the compositions and methods of the invention may be made without departing from the spirit or scope thereof and it is to be understood that the invention is intended to be limited only as defined in the appended claims.
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We Claim:
1. A method of manufacturing mosquito repellent coils consisting of cutting strings of natural fibre material of predetermined length; preparing a plastic dough or slurry containing a homogenous mixture of a pyrethroid as the active ingredient, a smoldering agent, a binder, an emulsifier and combustible fillers; dipping the strings in the dough or slurry until the strings are saturated with the dough; squeezing out any excess dough from the strings; coiling the dough laden strings into a desired shape and drying the coiled dough laden string to form the mosquito coil of this invention.
2. A method of manufacturing mosquito repellent coils as claimed in claim 1, in which the string is of any one or more of the natural fibres comprising jute, coconut, sisal, cellulose fibers, cotton, linen, hemp, ramie, rayon, viscose rayon, cuprammonium rayon, Acetate rayon, protein fibers, lime wool, silk and mixtures thereof.
3. A method of manufacturing mosquito repellent coils as claimed in claim 1, in which the active ingredient comprises allethrin, resmethrin, bioallethrin, used alone or in combination with citronella, lemongrass oil, lavender oil, cinnamon oil, neem oil, clove oil, sandal wood oil, eucalyptus oil, basil oil, calamus oil, and mixtures thereof.
4. A method of manufacturing mosquito repellent coils as claimed in claim 1, in which the smoldering agents are sodium nitrate, potassium nitrate, or mixtures thereof.
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5. A method of manufacturing mosquito repellent coils as claimed in claim 1, in which the filler is coconut shell powder or sawdust powder or a mixture thereof.
6. A method of manufacturing mosquito repellent coils as claimed in claim 1, in which the binder is guar gum.
7. A method of manufacturing mosquito repellent coils as claimed in claim 1, in which the emulsifier is unitox.
8. A method of manufacturing mosquito repellent coils as claimed in claim 1, in which a perfume is added to the dough or slurry.
9. A method of manufacturing mosquito repellent coils as claimed in claim 8, in which the perfume is a perfume selected from one or more of the following musk, cibet, ambergis, almond oil rosewood oil, cajeput oil, cananga oil, capsicum oil, caraway oil, cardamon oil. Carrot seed oil, cassia oil, cedar wood oil celery seed oil, cinnamon bark oil, citronella oil celary, sage oil, clove oil, cognac oil coriander koil, cubeb oil, camphor oil, dill oil, taragon oil, sweet fennel oil, galbanum resinoid, garlic oil, geranium oil, ginger oil, grapefruit oil, hop oil, absolute of hyacinth, absolute of jasmin, juniper berry oil, labdanum resinoid, lavender oil, bay leaf oil, lemon oil, lemongrass oil, lovage oil, mace oil, mandarin oil, absolute of mimosa, absolute of myrrh, mustard oil, absolute of narcissus, neroli oil, bitter orange, nutmeg oil absolute of mimosa, olibanum resinoid, onion oil, oponax resinoid, orange oil, concrete iris, pepper oil, peppermint oil, Perubalsam, petirgrain oil, pine needle oil, absolute of rose
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oil, sage oil, spearmint oil, storax oil, thyme oil balsa of tolu; absolute of vanilla, pod, vetiver oil, absolute of violet leaves and mixtures thereof.!'

10.A method of manufacturing mosquito repellent coils as claimed in claim 1, in which a coloring dye is added to the dough or slurry.
11. A method of manufacturing mosquito repellent coils as claimed in claim 10, in which the coloring dye is one selected from the group containing malachite green, amaranth dye, alizaryn dye stuffs, azo dye stuffs, and metal phthalocyanine dyestuffs, and trace nutrients such as salts of iron, manganese, boron, copper, cobalt, molybdenum and zinc.
12. A method of manufacturing mosquito repellent coils as claimed in claim 1, in which a preservative is added to the dough or slurry.
13. A method of manufacturing mosquito repellent coils as claimed in claim 12, in which the preservative is sodium benzoate.
14. A method of manufacturing mosquito repellent coils as claimed in claim
1, in which the strings are of jute fibres, the active ingredient is 0.1 to 2%
of the dough or slurry, the smoldering agent is 0.1-1% and more
particularly 0.1-0.5% ; the binder is 1 to 10 %; the combustible fillers are
85 to 90%, the emulsifier is 0.2 to 0.4 % of the total weight of the dough
or slurry.
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15.A method of manufacturing mosquito repellent coils as claimed in claim 12, in which the preservative is 0.5 to 0.7 % of the weight of the dough or slurry.
16.A method of manufacturing mosquito repellent coils as claimed in claim 10, in which the coloring dye is 0.2 to 0.3 % of the weight of the dough or slurry.
17. A method of manufacturing mosquito repellent coils as claimed in claim 8, in which the perfume is 0.5 to 1.5% of the weight of the dough or slurry.
18.A method of manufacturing mosquito repellent coils as claimed in claim 1, in which the strings have an internal diameter of 1.5-5cm and more particularly 1.3-3cm .
19.A method of manufacturing mosquito repellent coils as claimed in claim 1, in which the strings are of length ranging from 100 mm to 1 metre.
20. A method of manufacturing mosquito repellent coils as claimed in claim 1, in which the coils are dried naturally by evaporation of the moisture.
21. A method of manufacturing mosquito repellent coils as claimed in claim 1, in which the coils are dried by blow drying.
22. A method of manufacturing mosquito repellent coils as claimed in claim 1, in which the coils are dried by heating in an oven.
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23. A method of manufacturing mosquito repellent coils as. claimed in claim 1, in which the strings are wound helically to form a helical coil
24. A method of manufacturing mosquito repellent coils as claimed in claim 1, in which the strings are provided with an eye at one end before dipping for attaching the coil to a suitable fixture in its operative configuration.
25. A method of manufacturing mosquito repellent coils as described herein with reference to the example.

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ABSTRACT
A method of manufacturing mosquito coils consisting of cutting strings of natural fibre material of predetermined length; preparing a plastic dough or slurry containing a homogenous mixture of a pyrethroid as the active ingredient, a smoldering agent, a binder, an ernulsifier and combustible fillers; dipping the strings in the dough or slurry until the strings are saturated with the dough; squeezing out any excess dough from the strings; coiling the dough laden strings into a desired shape and drying the coiled dough laden string to form the mosquito coil of this invention.

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