WO2019202415A1

WO2019202415A1 - Natural mosquitoes repellent formulation

Info

Publication number: WO2019202415A1
Application number: PCT/IB2019/051594
Authority: WO
Inventors: Joy Snehalbhai TALATI; Manish Kumar Pratapnarayan MISHRA
Original assignee: Talati Joy Snehalbhai
Priority date: 2018-04-16
Filing date: 2019-02-28
Publication date: 2019-10-24

Abstract

This invention relates to a natural mosquitoes repellent formulation comprising: Geranium oil, Citronella oil, Rosemary oil, Lavender oil, Eucalyptus oil, and mixtures thereof. Further, the invention most particularly relates to a liquid natural mosquitoes repellent formulation comprising a mixture of natural oils, such as Geranium oil, Citronella oil, Rosemary oil, Lavender oil, and Eucalyptus oil, in the isopropyl alcohol (or ethanol) and further the vaporizer assembly including said liquid natural mosquitoes repellent formulation.

Description

Title: NATURAL MOSQUITOES REPELLENT FORMULATION

(1) FIELD OF THE INVENTION

The present invention generally relates to the field of mosquitoes repellant. The invention, particularly relates to a natural mosquitoes repellent formulation comprising: Geranium oil, Citronella oil, Rosemary oil, Lavender oil, Eucalyptus oil, and mixtures thereof. Further, the invention most particularly relates to a liquid natural mosquitoes repellent formulation comprising a mixture of natural oils, such as Geranium oil, Citronella oil, Rosemary oil, Lavender oil, and Eucalyptus oil, in the ethanol (or Isopropyl alcohol) and further the vaporizer assembly including said liquid natural mosquitoes repellent formulation.

(2) BACKGROUND OF THE INVENTION

There are many products available in the market as the mosquito repellent liquids and vaporizer assembly, some of them are containing natural liquids or most of them includes synthetic materials. Natural mosquito repellents are not widely accepted because of their mode of operation or inefficient working capability for longer period of usage with comparison to synthetic one because

Essential oils get degraded as it exposed to the atmosphere at quite elevated temperature, that’s why natural mosquito repellents haven’t seen huge market success and this type of assembly are not developed yet. There is a need to design an assembly in such a way that all practical problems related to the operation with Essential oils get eliminated and it can perform effectively and with very good efficiency. The best chemical for mosquitoes is DEET (N, N - Diethyl-meta - Toluamide), but it could not be used widely in the household application because of its severe effect on the central nervous system. After that there are some synthetic molecules of Pyrethroid insecticide like Prallethrin, Allethrin etc. Pyrethroid is an organic compound, similar to the natural

Pyrethrins produced by the flowers of Pyrethrums. Pyrethroids hold the majority of commercial household insecticides. By the concentrations that are used in such products, they may also have insect repellent properties and are generally harmless to human beings at low level of concentration, but it can harm sensitive individuals and they are known to be toxic even to aquatic organisms. These are widely used by the market because of no effect on the human and other living organisms at lower concentration, in all the products Pyrethroids are about 0.8 to 1.6%, and remaining contents are Paraffins, Parabens, Phthalates and other perfuming additives, preservatives, anti-oxidants are added to the mixture.

There are some Essential oils which have mosquito repellent property. Essential oils are chosen because of their volatility, pleasant smell and have mosquito repellent action and there are some oils which have some beneficial effect on the human body, so this is the step towards Green Chemistry. Some Essential oils which have mosquito repellent actions like Geranium oil, Rosemary oil,

Lavender oil, Citronella oil, Eucalyptus oil and Lemon grass oil. Here, some effects of Essential oils are described when they are used externally or internally, to confirm that these oils are totally safe in the atmosphere. In this invention Essential oils will be contacted to the humans by vapour phase only, till yet these oils are used in foods, skin treatment, nourishment of hair, healing, wounding and as an anti-infectant or anti -bacterial. So if these Essential oils are safe when applied to skin then they are totally safe when used in the vaporizer as a mosquito repellent liquid. Here some uses of Essential oils are described for each.

Geranium oil can aid in uplifting mood, lessening fatigue and promoting emotional wellness. It contains antibacterial, antifungal and antioxidant properties. It can aid in inhibiting the bacterial strains. It assists in detoxification by increasing the rate of urination. This process of elimination does not only remove toxins from body, but also aids in digestive function and helps inhibit the excess gas in intestines. Geranium oil does not generally cause side effects. It cause some skin irritation when it is applied directly without dilution, otherwise it is totally safe in vapour phase. Eucalyptus oil can be used to sniff or to use it in the steam therapy. Citronella oil also mainly applied to skin as a prevention of mosquito bites. Rosemary oil can be used to support healthy digestion and healthy respiratory function and also helps to reduce nervousness, tension and fatigue. Lemon grass oil is a great addition to various skin care and cosmetic products, such as soaps, deodorants, shampoos, lotions and tonics. It is also known for its ability to repel insects, such as mosquitoes and ants, due to its high Citral and Geraniol content. It is the property of Essential oil that it cause constipation, headache, and increased appetite, when it is taken by mouth. Essential oils can cause irritation to the skin when it is applied directly. So, this vaporizer is only going to create an atmosphere of these Essential oils so it is totally safe from the view of health issues.

A number of different types offormulations having mosquitoes repellant effects and accessories for using such formulationsare available in prior art. For example, the following patents are provided for their supportive teachings and are all incorporated by reference: Prior art document, ETS6953814 discloses topical insect repellent with extended duration of protection was obtained from mixtures of molecules based on two or more volatile repellent organic molecular species occurring naturally on the human skin surface.

Another prior art document, ETS5594029 discloses use of natural or synthetic first runnings coconut fatty acid as an insect-repellent agent which is applied to human or animal skin or to clothing.

Yet another prior art document, ETS5776477 discloses a topical pest repellent. The topical pest repellent comprises a variable mixture of natural ingredients including pennyroyal herb, tansy herb, calendula, citronella, pyrethrin and aloe vera. A method is provided to produce tinctures which are combined to form a composition for application to skin of animals such as horses to repel pests such as flies, mosquitoes, ticks, and other insects.

Yet another prior art document, US7152809 and US7007861 disclose methods and devices for repelling insects. The methods and devices provide personal protection from insect bites and insect landings, particularly mosquito bites. The methods and devices employ insect repellents such as pyrethroids at low (parts per billion) levels. Yet another prior art document, US7946748 discloses a mosquito repellent lamp. The mosquito repellant lamp comprising a lamp holder, which is provided with a lamp shade with luminous tube; a power switch for turning on and off the power; a mosquito repellent device mounted above said lamp shade; featured by that: said mosquito repellent device is provided with a cavity for contain mosquito repellent patch, which is provided with air inlets and outlets, which are interconnected, and a fan corresponding to the air inlets, said fan and said luminous tube are powered through a switchboard, which is connected with a fan switch for turning and stopping said fan. Yet another prior art document, US8753695 discloses a dry insect repellent, which includes a plurality of non-toxic natural essential oils and an amount of soybean oil, to facilitate even distribution of the active components throughout a dry carrier matrix. The dry carrier matrix facilitates storage, handling, and application of the dry insect repellent to a treatment area for the safe and effective control of mosquitoes and other pests.

Yet another prior art document, US9700041 discloses an insect repellent patch. The insect repellant patch is of a size and weight compatible for wearing on the clothing or skin of a user. The patch has a gross area not in excess of 232 cm2 and bearing one or more insect repellents having a vapor pressure at 25° C. of not less than about 1 x 10-6 mm Hg. The total amount of insect repellent is in an amount effective to provide practical mosquito personal area repellency.

Yet another prior art document, US5106622 discloses an environmentally safe, topical pest repellent. The repellent action is attributable to a mixture of natural oils of citronella, cedar, and wintergreen. These natural oils, mixed in equal amounts, are combined in a non-toxic base, such as olive oil.

Yet another prior art document, USD466578S1 discloses a novel design of mosquito repeller.

Yet another prior art document, WO2017168449 discloses a herbal composition for repellency of at least Anopheles, Aedes and Culex mosquitoes for at least eight hours when applied to the body. In one embodiment of this invention, the herbal composition comprises three or more than three essential oils. The herbal composition of this invention has been illustrated 5 with use of a cream containing three essential oils: Citronella oil, Catnip oil and Kaffir lime oil.

Yet another prior art document, US20150272133 discloses a composition for repelling insects, for example, mosquitoes. The composition comprises citronella oil, lemongrass oil and rosemary oil, and a carrier. The composition of the invention may be provided on an incense stick, incense coil, incense cone or in a candle, which may be smoldered or burnt in order to produce its insect repelling functions.

However, above mentioned references and many other similar references has one or more of the following shortcomings: (a) harmful synthetic chemicals are used in preparing mosquitoes repellent formulations; (b) mosquitoes repellent formulations are topically applied on the skin; (c) expensive; (d) not effective to kill mosquitoes; (e) smells bad; (f) not easy to use; (g) can only be used in patch form; and (h) can be used only in solid form. The present application addresses the above mentioned concerns and short comings with regard to providing a natural mosquitoes repellent formulation comprising essential oil and also providing a vaporizer assembly. (3) SUMMARY OF THE INVENTION

In the view of the foregoing disadvantages inherent in the known types of mosquitoes repellant formulations and accessories for using such formulationsnow present in the prior art, the present invention provides an improved natural mosquitoes repellant formulation. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new and improved natural mosquitoes repellant formulation which has all the advantages of the prior art and none of the disadvantages. An object of the invention is to provide a natural mosquitoes repellent formulation comprising: Geranium oil, Citronella oil, Rosemary oil, Lavender oil, Eucalyptus oil, and mixtures thereof.

It is another object of the present invention to provide the natural mosquitoes repellent formulation, wherein said natural mosquito repellent formulation comprises at least 35% Geranium oil.

Yet another object of the present invention to provide the natural mosquitoes repellent formulation, wherein said natural mosquito repellent formulation comprises at least 20 % Citronella oil.

Yet another object of the present invention to provide the natural mosquitoes repellent formulation,, wherein said natural mosquito repellent formulation comprises at least 0.1 % Rosemary oil. Yet another object of the present invention to provide the natural mosquitoes repellent formulation, wherein said natural mosquito repellent formulation comprises at least 3% Lavender oil. Yet another object of the present invention to provide the natural mosquitoes repellent formulation, wherein said natural mosquito repellent formulation comprises at least 0.1 % Eucalyptus oil.

Yet another object of the present invention to provide a natural mosquitoes repellent formulation comprises Geranium oil in the range of 35 to 60% to the total formulation; Citronella oil in the range of 20 to 40% of the total formulation; Rosemary oil in the range of 1% to 9% to the total formulation; Lavender oil in the range of 1% to 9% to the total formulation; and 1 to 10% Eucalyptus oil.

Yet another object of the present invention is to provide the natural mosquitoes repellent formulation, wherein said natural mosquito repellent formulation is in the form of liquid, solid, semi solid, or semi liquid. Yet another object of the present invention is to provide the natural mosquitoes repellent formulation, wherein the natural mosquito repellent formulation is in the liquid form.

Yet another object of the present invention is to provide the natural mosquitoes repellent formulation, wherein the natural mosquito repellent formulation in the liquid form is prepared by mixing the natural mosquito repellent formulation in organic solvent or in mixture of organic solvents.

Yet another object of the present invention is to provide the natural mosquitoes repellent formulation, wherein the natural mosquito repellent formulation and organic solvent or in mixture of organic solvents has the ratio in the range of 40:60 to 80:20.

Yet another object of the present invention is to provide the natural mosquitoes repellent formulation, wherein the natural mosquito repellent formulation and organic solvent or in mixture of organic solvents has the ratio 70:30.

It is another object of the present invention is to provide a vaporizer assembly for repelling mosquitoes comprises:A material holder wherein a liquid natural mosquito repellent formulation is placed; a wick, wherein said wick is placed on to a wick holder and is supported by a wick supporter; and a heating arrangement, wherein said heating arrangement is placed at the lower end of said wick. Yet another object of the present invention is to provide the vaporizer assembly, wherein said wick is made up of plaster of paris material.

Yet another object of the present invention is to provide the vaporizer assembly, wherein said heating arrangement operates in the temperature range of 50 to 75 °C to evaporate said liquid natural mosquitoes repellent formulation.

The present invention has several advantages. The present invention is to provide the mosquito repellent liquid formulation and vaporizer assembly which is made up from natural Essential oils, which don’t have any drawbacks/side-effects. One of the advantages of the present invention is to provide the best mosquito repellent action with the pleasant smell and to eliminate the hazy atmosphere because of the presence of hydrocarbons in conventional products. Another advantage is to provide the new assembly and to have the good results than the existing one, which is much more effective and use the minimum amount of oil without compromising with efficiency. Yet another advantage is to provide vaporizer is to eliminate the deficiency of natural oils. Essential oils lose their mosquito repellent action after 5 days of use, due to degradation/decomposition of some molecules at elevated temperature and have some deteriorated smell. In the present invention model designed in such a way that Essential oils give their best results. Natural Essential oils have a capability that it can perform much better than any synthetic molecules. Another object is to minimize the usage of synthetic molecules and some other chemicals which have harmful effect on the living systems, other systems like UV light, mat, mosquito net, electric racket, mosquito repellent cream etc. Yet another object is to minimize the diseases/death caused by the mosquito bites, which can be eliminated or reduced up to such extent. The main advantage of the invention is to move towards green chemistry, by eliminating the usage of synthetic molecules which have long term impact on the living organisms. In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.

These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention.

(4) BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein: Fig-1 depicts illustrative vaporizer assembly according to one of the embodiment of the present invention.

(5) DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that the embodiments may be combined, or that other embodiments may be utilized and that structural and logical changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents. Accordingly, the present invention is about to develop a natural mosquito repellent liquid formulation and vaporizer assembly in which 3 sections are there: wick, liquid formulation, vaporizer (A mean to disperse liquid formulation in the surrounding).

In the one embodiment, wick is fabricated from different materials like Plaster of Paris (Calcium Sulphate), white cement, different types of hydrophobic chemicals in clay to introduce hydrophobic nature in the wick, Polyvinyl Alcohol (or Polyvinyl

Pyrrolidone), different grade of Plaster of Paris. After fabrication of the wick, vaporization rate in Citronella oil is analysed. From this wick’s material of fabrication is decided based on vaporization rate and strength. It also depends on the wettability of the material. In the other embodiment formulation of Essential oil mixture is done by carrying out experiments in 1*1 (feet) acrylic chamber on 25 mosquitoes. And based on knockdown time taken by each Essential oil composition is selected, initially all the selected oil’s knockdown time is checked even after 7 days of use if it gives comparatively good results then that particular oil is selected. And other formulations are tested in the same setup.

Further, knockdown time is checked at the different temperatures in the vaporizer, that will be decided on the basis of smell and knockdown time, because at higher temperature Essential oils are went under degradation process and gives some bad smell.

In the other embodiment, finalized wick and mixture of Essential oils with optimum concentration is done and their knockdown time is checked, from that optimized results are considered and followed in the next embodiment.

In the other embodiment, the finalized formulation of liquid is diluted with Ethanol (or Iso-propyl Alcohol) at different percentages and their knockdown time is measured, from which the best concentration is selected as the final one.

In another embodiment, the finalized formulation of liquid is checked with the final material of wick at the fixed temperature, by checking all the parameter affecting directly or indirectly. A vaporizer assembly for repelling mosquitoes is explained below. Various experiments (experiments 1 to 3) for selecting the wick materials and vaporizer assembly is explained in detailed in the following section. Fig. ldepicts illustrative vaporizer assembly according to one of the embodiment of the present invention. A vaporizer assembly for repelling mosquitoes comprises: a material holder wherein a liquid natural mosquito repellent formulation is placed; a wick; wherein said wick is placed on to a wick holder and is supported by a wick supporter; and a heating arrangement, wherein said heating arrangement is placed at the lower end of said wick.There are 3 main parts of mosquito repellent liquid formulation and vaporizer assembly. 1) Wick 2) Liquid formulation 3) Vaporizer (A mean to disperse liquid formulation in the surrounding).

WICK: Mainly marketed mosquito repellent systems are using carbon wick with some binding agents to convey the liquid formulation to the vaporizer which is electrically heated. Main characteristic of the wick is its wettability characteristic and capillary action, its porosity also affects the vaporization rate. On the initial setups conventional vaporizer are used. It is a tendency of any material to get wet through capillary action by the like liquid. Due to high temperature in vaporizer, formulation which is trapped in the wick (after get wetted throughout), which get vaporized into atmosphere. So as the liquid get vaporized from the wick, remaining liquid formulation saturates the wick up to saturation limit, that limit depends on the wetting characteristic and hold up of material depends on its porosity.

It must convey the material to the heating zone of vaporizer machine section to get vaporized at certain rate in certain temperature range. And materialswhich have specific strength that strength must be there even after get wetted throughout its length.

First of all, material of wick must be decided according to its vaporization rate, it must remain constant throughout the period of use, to maintain the concentration of

Essential oil in the surrounding atmosphere. The rate of vaporization should neither be high which may be too intense nor too low which may not be able to maintain the mosquito free atmosphere. Wick is made up of different materials and compositions. On the initial stage, experiment started with Plaster of Paris, along with the different percentage of clays. Wick which is made up from Plaster of Paris has the almost constant vaporization rate that’s the good nature so that other experiments will be continued with the Plaster of Paris as a main material of construction. Normal grade of Plaster of Paris is able to bind the clay up to 40% by its weight, for more than 40% of clay having wick loses its binding characteristic and doesn’t have enough strength to remain as such in the particular shape. So that it is possible to have some good strength in 20% and 30% composition with clays. All the clays are pass through 425 m size mesh screen. Different clays are used as follows: (1) CTAB = Cetrimonium Bromide, (2) CAPB = Cocoamidoproplyne Betaine. Citronella oil (which is commercially available in the market) is used on the primary stage as a vaporizing liquid to check out the vaporizing rate. All the experiments are conducted at 25°C and results are conducted at every 10 hours. Here, citronella oil is used as a solvent only for testing of the conveying rate of wick at higher temperature, because main content in liquid formulation is related to the species of citronella oil which will be described in liquid formulation section. For all the setups this wick is fixed in the vaporizer which is available in the market. Procedure for Fabrication of Wick

Powdered (fine particle size) Plaster of Paris is taken in the container pour same weight of water in it with continuous stirring to make the uniform mixture. Plaster of Paris takes about 7-8 minutes to bind up and to have the proper shape. So, after adding up water in the equal weight of Plaster of Paris, after proper stirring, this thick slurry is poured in module having diameter around 1 cm and length around 7 cm. After keeping it for 7-8 minutes these samples are taken out and keep it as it is for 1 day to get the proper strength and exposed in the sunlight for 4-5 days to remove all the trapped moisture in the structure. Then these wick is ready to use. For the case of Poly-vinyl alcohol or Poly-vinyl Pyrrolidone these polymers are not readily soluble, so at quite higher temperature or by stirring it get dissolved easily.

Then this polymer solution is used instead of water, equal weight of polymer solution is taken with Plaster of Paris and poured in the module. This polymer solution gives extraneous strength to the material.

EXPERIMENT-1 In this experiment, wick is made up of 20% clay of different types and remaining 80% is normal grade Plaster of Paris. Graph for this experiment is shown below, it shows percentage of liquid formulation remaining in refill with respect to time. Untreated clay is hydrophilic, which capture moisture from the atmosphere, to introduce hydrophobic nature to untreated clay-CTAB and CAPB are added in concentration of 3% and 1% respectively. After treating with different chemicals, it dried totally in oven and pass through sieve which having aperture size 425 m. Wick is shaped by using module which have diameter approximately lcm and length is about 7cm. It dried for 4 to 5 days in sunlight. Then it is placed in refill which is filled with citronella oil. Wick is heated in vaporizer machine. For this experiment, results are shown below:

Here, untreated clay containing sample is using minimum amount of citronella oil with respect to 3% CTAB and 1% CAPB samples. This table concludes that untreated clay and normal grade of Plaster of Paris having good vaporizing characteristic.

EXPERIMENT-2

In this experiment, wick is made up of 30% clay of different types and remaining 70% is normal grade of Plaster of Paris. These samples are made to check the vaporization rate on changing the concentration of clay. All the samples are prepared by same method as per described in the I^st experiment. Results are shown below:

Here, the results are showing that untreated clay is using minimum amount of citronella oil with respect to other two samples 3% CTAB and 1% CAPB. Above two experimental results, concludes that sample having untreated clay and Plaster of Paris are best samples for the using it as the wick in mosquito repellent vaporizer system.

From the results of experiment- 1 and 2, it shows that UNTREATED CLAY + PLASTER OF PARIS (20% or 30%) have the minimum usage of Essential oil, so these samples are the best and as the tables show that both the wicks are using almost same amount of oils. Now the secondary concern is to have the strength and vaporization rate variation with change in material to get the more strength.

EXPERIMENT-3

Furthermore, try to modify the strength and vaporization rate of samples by adding white cement, but after addition of white cement binding characteristic of Plaster of Paris get disturbed and have the sintered structure and loses its wetting characteristic as these samples actually require. Another option for modification by adding different percentages of high grade of Plaster of Paris which is normally used by dentists for construction of denture. For that experiment 3 is described below: From above two experiments (Experiments 1 and 2), finalized material of wick is Plaster of Paris and 30% untreated clay, now just to modify the strength and vaporization rate high grade of Plaster of Paris is used. Only for testing 3 samples are prepared having 5%, 10% and 20% concentration of high grade of Plaster of Paris. For this experiment results are shown below:

Result shows that by adding high grade of Plaster of Paris, it provides good strength but it makes the sintered structure and reduces the rate of vaporization, which is very low. Here, in graph B-POP = normal grade of Plaster of Paris and A-POP = high grade of Plaster of Paris.

The material of wick is untreated clay and normal grade of Plaster of Paris, tried to modify the strength and vaporization rate by adding high grade of Plaster of Paris, but it sinters the material so it cannot be applicable.

According to the vaporization rate material of wick is UNTREATED CLAY + NORMAL GRADE OF PLASTER OF PARIS. Now as described in the criteria for selection of wick, which is strength. For that samples are made from Plaster of Paris in 0.5% polyvinyl alcohol in the water procedure described in the I^st experiment. This polymer gives strength to the material than the normal chalk made up of POP and provides desired vaporization rate. So, for low temperature usage, 3 main samples for the further testing are: 1) 20% untreated clay+ POP2) 0.5% Polyvinyl Alcohol in the water to bind POP, 3) pure Plaster of Paris, Whichever wicks are selected they all have very good strength, which can sustain tensile pressure above 12 kg/cm2. Now, in the following below section of mosquito repellent system, that is liquid natural mosquitoes repellant formulation.

Different experiments were carried out to finalize and select the best natural mosquitoes repellant formulation. Herewith in the following below section - liquid natural mosquitoes repellant formulation is described. The detailed experimental condition and results are provided in the experiments 4 to 9.

Most popular and highly effective mosquito repellent is DEET (N,N-Diethyl-3- Methylbenzamide), which having very good mosquito repellent property with respect to any other repellents. But it cannot be applicable in household applications due to its fatal effect on living organisms. So here, tried to move towards green chemistry. There are some natural Essential oils available which having very good mosquito and bug repellent property. There are several Essential oil but here selected some Essential oils are Lemongrass oil, Eucalyptus oil, Geranium oil, Rosemary oil, Lavender oil. These all the oils are naturally available and no harmful effect on any living organism, also all they have very good aroma.

Whichever oils are going to use in these experimental setup have volatile nature above ambient temperature, on the initial stage used vaporized is designed at about 90-95°C, later which will be modified according to temperature requirement of Essential oil composition. After getting the final liquid formulation which has best mosquito repellent action, to observe the mosquito repellent action of different oils and different composition of them.

Setup arranged to check out the repellent action of Essential oils on mosquitoes: Here, for the present invention whichever Essential oils are selected on primary level that all are on the basis of their mosquito repellent action, as tests move on they all are separated and considered them according to their price, smell and nature. These Essential oils are tested of different grade and quality. From these oils some of them are selected for preparation in liquid formulation. Final Essential oils used in this invention are: Geranium oil, Citronella oil, Lemon grass oil, Rosemary oil, Lavender oil, Eucalyptus oil. For all the setups vaporizer is kept in the 1*1 (feet) acrylic chamber and started electrically and 25 mosquitoes are injected in the chamber and readings are taken in the form of time to knock down all the mosquitoes. For these sets of experiments, Essential oils have almost same knockdown time on the initial stage (day-l) so it’s difficult to sort out them on the basis of only 1 day of use. For that sorting all the samples are used for 7 days and then tested in chamber, because of decomposition its knockdown will be quite more than the day-l, but it is easily estimated the performance of Essential oils, whichever will have the lowest knockdown time even after 7 days of use that will be selected for the next set of experiments.

EXPERIMENT-4

In this experimental setup, all the Essential oils are taken in pure (100%) concentration and kept in the vaporizer have temperature quite higher about 90°C. These are the readings:

Here, all the oil samples are tested at the I^st day of experiment and then they are used constantly for 1 week (daily 10 hours) and they are tested again after 1 week. Whichever oil have good repellent action even after 1 week of use that are selected for the next series of tests. Except Lemon grass oil, all the oils have good repellent action. In the next series of tests these oils are used in the different composition.

EXPERIMENT-5 There is a problem with natural oils that they are too sensitive and get deteriorated as time passes with the usage and this process is too faster at higher temperature because Essential oil get decomposed at elevated temperature. This happens only at higher temperature otherwise its mosquito repellent property remains as such if it is not exposed to the higher temperature. So there is a provision of temperature, as lowest temperature is possible that will be preferred, without compromising with its release rate and knockdown property. For that temperature 60°C & 80°C are selected and these all the oils are tested once again. This temperature can be maintained by different type of mechanism. According to the cost and operational sustainability this system can be modified. The results are as below:

Essential oils are getting degraded at the elevated temperature so here setup is conducted at 60° and 80°C. So, 60°C is the appropriate temperature at this temperature Essential oil mixture is not getting decomposed. By making slight change in the circuit, in the cut-off temperature can be modified to maintain temperature +-lO°C around designed temperature.

So, from now all the vaporizer machines are assembled with bimetallic switch of 60°C.

EXPERIMENT-6

From above two setups, finalized 5 Essential oils are taken in different concentration at 60°C. In all the batches Essential oils are taken in different amount to decide their mutual activity in the mixture. Results are as follows: For that some notations are adopted, Geranium oil =A, Citronella oil=B, Rosemary oil=C, Lavender oil=D, Eucalyptus oil=E.

From this experiment, conclusion is that Geranium oil have most pleasant smell and have maximum mosquito repellent property for a long period with respect to others. So in all the compositions geranium oil is kept in large amount to maintain smell in the atmosphere. Except Geranium and Citronella oil, remaining 3 oils have comparatively less repellent action, but they are taken in small amount to have the smell and as an additive to the formulation to maintain the release rate. Rosemary oil is dense but it has intense mint smell so it is kept 5% in the batch no-2. Where Eucalyptus oil degrade very rapidly and has good effect on mosquitoes. So Eucalyptus and Rosemary is taken in very low concentration as an additive.

So, composition taken in batch-2 is much appropriate. EXPERIMENT-7

Till now all the experiments and batches are done with pure Essential oil without dilution. In this setup batch-2 from the experiment-6 is being diluted with Isopropyl Alcohol (IP A) of different concentrations. Ethyl alcohol also can be used as a solvent, IPA and ethyl alcohol both have no effect on mosquitoes. It is more convenient than the IPA, in the final setup ethyl alcohol will be used as a solvent.

Main composition: 50% Geranium oil + 30% Citronella oil + 5% Rosemary oil +

10% Lavender oil + 5% Eucalyptus oil

This main composition is diluted with IPA, for that readings are as follows:

Here, the main priority of above results to have the best diluted mixture has the most pleasant smell, and to have very good mosquito repellent action means low knockdown time and it has the least concentration of Essential oils. Here in batch no. 4 & 5 have almost same knockdown time readings for 25 mosquitoes, but batch no.4 is selected because it has the lowest concentration and has the significant effect on mosquitoes even after 7 days of use. As results shown in experiment- 1 & 2, all the Essential oils have knockdown time around 12-14 minutes on the initial 2-3 days. It is required to have the liquid formulation with the best mosquito repellent action, relatively cheap and to have the pleasant smell. All these requirements are satisfied and fulfilled by the 70% Concentration of main composition and remaining 30% is solvent IP A or ethanol. But ethanol is used because it has no effect on the humans. So it’s more appropriate than the ethanol. Here the liquid formulation section ends. Now, Wick section’s and liquid formulation section’s results will be combined together. From that results, 3 finalized samples are tested once again for the vaporization rate and mosquito’s knockdown testing, whichever sample will have the lowest vaporizing rate and best mosquito repellent property at around 60°C (+- l0°C). For this setup, there is a need to prepare a polymer solution for that 0.5% Poly-vinyl alcohol is added in the water and get dissolved after application of heat and stirring. This polymer solution is then used instead of water and same weight of Plaster of Paris is taken and poured into module and wick is fabricated by this mean.

EXPERIMENT-8

In this experiment finalized wicks taken are: 1) 30% (20% also can be taken) untreated clay + POP 2) 0.5% Polyvinyl Alcohol in the water to bind POP, 3) Pure Plaster of Paris.

All these 3 are taken with 70% Concentration of main composition and remaining 30% is solvent ethanol. These wicks are dipped in the individual container and wait until the whole wick is wetted throughout. Then it is joined with the vaporizer and placed in the chamber (1*1 feet) and note down the knockdown time for 25 mosquitoes. Then to know about their vaporization rate, first of all weight of the sample is measured and then it is being used for 12 hours after that again it’s weight is measured, by that way it’s vaporization rate is calculated, whichever will use less oil that will be chosen :

5

In the above 5 samples, all 5 have almost same effect on mosquitoes. So now choice will be dependent on the vaporization rate. Whichever sample will use less amount of oil and it can maintain that atmosphere for long time that will be the final selected material. The results conclude that 2^nd sample which is 0.5% of Poly-vinyl alcohol in

10 water with Plaster of Paris. This sample fulfil the requirements of mosquito repellent action and minimum usage but it cannot maintain that atmosphere because of its low vaporization rate. And the other two have the mostly same vaporization rate and effect on mosquitoes, but the problem with these two samples are that they have little bit of higher vaporization rate, that gives little bit of intense atmosphere. So, the finalized sample will be Pure Plaster of Paris made up with pure water, which has the optimized vaporization rate and knockdown time for mosquitoes.

EXPERIMENT-9

The final formulation having too pleasant smell, although to modify the smell slight amount of peppermint oil is used. Peppermint oil also have the mosquito repellent property and have a mint type smell which helps to create a fresh atmosphere with mint type of smell, because it contains menthol and menthone. Also it is used in the cosmetics, chewing gum, food, beverages as a flavouring agent. So it is safe to use it with the finalized oil formulation. For that slight amount of change is made in the liquid formulation. As methanol having severe effect on mosquitoes, but it has some effect on humans if it permits some concentration in the vapour phase so it is used in the solvent in very small concentration. For that results are as per below:

So the finalized formulation will be: 70% main composition (49% Geranium oil + 29% Citronella oil + 4% Rosemary oil + 9% Lavender oil + 4% Eucalyptus oil + 5% Peppermint oil) + 25% Ethanol + 5% Methanol, which creates much pleasant smell than the result formulation of experiment-7.

Wick material, vaporizer design and oil formulation are finalized, which have very good results. Moreover this product is made up from natural entities which have no side-effects, pleasant smell, no health issue, environment friendly nature of material, easy to assemble, efficient action towards mosquitoes. So the assembly will be: Wick is made up from pure Plaster of Paris with water only and liquid formulation contains: 70% main composition (49% Geranium oil + 29% Citronella oil + 4% Rosemary oil + 9% Lavender oil + 4% Eucalyptus oil + 5% Peppermint oil) + 25% Ethanol + 5% Methanol and the designed temperature of the vaporizer is 60°C. Essential oils are not widely used in this type of mosquito repellent assembly, because they get degraded / decomposed at the elevated temperature. That’s why this type of products don’t exist in market. Vaporizer used in the other mosquito repellent system have design temperature around 90-95°C, which is according to formulation of liquid. This vaporizer cannot be used for present invention, because for the present invention’s liquid formulation have design temperature around 60°C.

In the present invention problem related to decomposition of Essential oil is eliminated by holding up very small amount of Essential oil formulation which is sufficient for one night (10-11 hours) which is around 3-4 ml. Essential oil go downward as the oil from the bottom end of the wick get vaporized, again by the

Essential oils wick’s bottom end get saturated by gravitational force. These cyclic processes go on till the whole usage period. Whatever amount of Essential oil get vaporized same amount of oil will be automatically come to that bottom site through gravitation force. On top of the assembly this formulation is filled when holdup level goes down, it can be refilled manually. To have the support throughout the length of wick, wick supporter is present from bottom to top. Oil holder has slight slope so it gives path to the liquid formulation. At the bottom, coil is placed at the lower end of the wick, which is heated electrically by different mean at 60 °C (+-5 °C). At the bottom tip of the wick, there is a wick holder which gives base to the wick. Wick can be replaced from the top if it get broken for that the slight inclined line is at the top from the wick supporter, so it gives sufficient space for the wick to take out that one easily and fit the new wick in the assembly. If by any mean this wick breaks then it can be easily replaced with the new one.

The natural mosquitoes repellant formulation of the present invention can also be used in a different forms such as solid, semisolid, and semi liquid. The natural mosquitoes repellant formulation is made up of natural essential oils which are not harmful, so it can also be topically applied on the skin in the form of ointment or as a paste. Further prior art document, WO2017168449 discloses a herbal composition for repellency of at least Anopheles, Aedes and Culex mosquitoes for at least eight hours when applied to the body. The prior art reference WO2017168449 also discloses a polyhedral body cream made from a mixture of essential oils. The natural mosquitoes repellant formulation can also be prepared in the cream based form as discussed in the prior art document, WO2017168449. The natural mosquitoes repellant formulation can also be either applied directly on mats / incense sticks (or any other similar materials) or while preparation can also be combine with the materials of mats / incense sticks (or any other similar materials).

It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-discussed embodiments may be used in combination with each other. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description.

The benefits and advantages which may be provided by the present invention have been described above with regard to specific embodiments. These benefits and advantages, and any elements or limitations that may cause them to occur or to become more pronounced are not to be construed as critical, required, or essential features of any or all of the embodiments. While the present invention has been described with reference to particular embodiments, it should be understood that the embodiments are illustrative and that the scope of the invention is not limited to these embodiments. Many variations, modifications, additions and improvements to the embodiments described above are possible. It is contemplated that these variations, modifications, additions and improvements fall within the scope of the invention.

Claims

CLAIMS:

1. A natural mosquitoes repellent formulation comprising: Geranium oil, Citronella oil, Rosemary oil, Lavender oil, Eucalyptus oil, and mixtures thereof.

2. The natural mosquitoes repellent formulation according to claim 1, wherein said natural mosquito repellent formulation comprises at least 35% Geranium oil.

3. The natural mosquitoes repellent formulation according to claim 1, wherein said natural mosquito repellent formulation comprises at least 20 % Citronella oil.

4. The natural mosquitoes repellent formulation according to claim 1, wherein said natural mosquito repellent formulation comprises at least 1 % Rosemary oil.

5. The natural mosquitoes repellent formulation according to claim 1, wherein said natural mosquito repellent formulation comprises at least 3% Lavender oil.

6. The natural mosquitoes repellent formulation according to claim 1, wherein said natural mosquito repellent formulation comprises at least 1 % Eucalyptus oil.

7. A natural mosquitoes repellent formulation comprises Geranium oil in the range of 35 to 60% to the total formulation; Citronella oil in the range of 20 to 40% of the total formulation; Rosemary oil in the range of 1% to 9% to the total formulation; Lavender oil in the range of 1% to 9% to the total formulation; and 1 to 10% Eucalyptus oil.

8. The natural mosquitoes repellent formulation according to claims 1 and 6, wherein said natural mosquito repellent formulation is in the form of liquid, solid, semi solid, or semi liquid.

9. The natural mosquitoes repellent formulation according to claims 8, wherein the natural mosquito repellent formulation is in the liquid form.

10. The natural mosquitoes repellent formulation according to claims 9, wherein the natural mosquito repellent formulation in the liquid form is prepared by mixing the natural mosquito repellent formulation in organic solvent or in mixture of organic solvents.

11. The natural mosquitoes repellent formulation according to claims 10, wherein the natural mosquito repellent formulation and organic solvent or in mixture of organic solvents has the ratio in the range of 40:60 to 80:20.

12. The natural mosquitoes repellent formulation according to claims 11, wherein the natural mosquito repellent formulation and organic solvent or in mixture of organic solvents has the ratio 70:30.

13. A vaporizer assembly for repelling mosquitoes comprises:

A material holder wherein a liquid natural mosquito repellent formulation is placed;

A wick; wherein said wick is placed on to a wick holder and is supported by a wick supporter; and

A heating arrangement, wherein said heating arrangement is placed at the lower end of said wick.

14. The vaporizer assembly according to claim 13, wherein said wick is made up of plaster of paris material.

15. The vaporizer assembly according to claim 13, wherein said heating arrangement operates in the temperature range of 50 to 75 °C to evaporate said liquid natural mosquitoes repellent formulation.