DESC:FIELD OF INVENTION

The present invention relates to a paradichlorobenzene based air freshener and more particularly to a paradichlorobenzene based air freshener with high fragrance content and a method for preparing the same.

BACKGROUND OF INVENTION

The air fresheners in the form of solid blocks are well known. A large number of these solid blocks comprise paradichlorobenzene as the major ingredient due to its high sublimation rate, easy availability, low cost and low solubility in water. Paradichlorobenzene is used to control moths, moulds and mildew. It also finds use as a disinfectant in waste containers and restrooms and has the characteristic odor associated with urinal cakes. Its usefulness for these applications arises from its low solubility in water and relatively high sublimation rate. It sublimes readily near room temperature. Paradichlorobenzene has a strong, characteristic odor. To mask the native odor of paradichlorobenzene it is recommended to add pleasant fragrances to make it more acceptable to consumers.
As per the conventional method of manufacturing paradichlorobenzene based solid air freshener, a suitable fragrance is allowed to mix with paradichlorobenzene for a few minutes and then the mixture is punched to provide paradichlorobenzene based air freshener of the desired shape.
A problem with this conventional method of manufacturing of said paradichlorobenzene based solid air freshener is that only a very small amount of fragrance can be added. It has been found that the maximum amount of fragrance that can be added in paradichlorobenzene based air fresheners is below 0.8%. Higher fragrance dosages are not possible because of problems like air freshener not being formed or leaching of fragrance out of it.
In spite of decades of improvement, paradichlorobenzene based air fresheners with higher fragrance dosages are not possible because of leaching of fragrance over a period of time. This is because the perfume may migrate completely onto the surface of the air freshener before the consumer has a chance to open the package resulting in an unpleasant “wet” appearance of the air freshener. In this case there would also be a strong diffusion of the perfume in the initial stages of use as most of the perfume is located on the surface of the air freshener. Once the perfume on the surface has completely diffused, the performance of the air freshener becomes weak.
Further, leaching may occur at the time of packaging. Thus, paradichlorobenzene based air fresheners with higher fragrance dosage might not be feasible for manufacturing.
It is desirable to increase the perfume dose so that the effect of air freshener would be enhanced. Several attempts have been made at achieving the same. For instance, Japanese Patent Publication No. 60078926 discloses a method to obtain paradichlorobenzene crystal having increased fragrance without causing dissolution and wetting of the crystal, by dissolving polyvinyl pyrrolidone or hydroxypropyl cellulose in a perfume and adding this solution to a mixture of paradichlorobenzene and magnesium metasilicate aluminate.
JP3810853 discloses an oily material containing paradichlorobenzene formulation which is prepared by adding a hold-back agent (e.g.; a diester of phthalic acid) and an oily material to paradichlorobenzene. The hold-back agent suppresses the volatilization of the oily material. The paradichlorobenzene present in said formulation uniformly volatilizes along with the oily material, leaving no residue behind. Thus said paradichlorobenzene formulation does not lead to the leaching of the oily material.
The present invention aims to mitigate all the drawbacks in the prior arts and conventional products available in the market. A novel paradichlorobenzene based air freshener is provided herein which has much higher fragrance content than the conventional air fresheners without the problem of fragrance leaching out. A method of manufacturing the same is also provided. The paradichlorobenzene based air freshener of present invention is formed such that the rate of sublimation of paradichlorobenzene and the rate of vaporization of the fragrance are uniform so that no residue is left after the air freshener is consumed.

SUMMARY OF INVENTION

In accordance with an embodiment of the invention there is provided a paradichlorobenzene based air freshener having high fragrance content.
In accordance with another embodiment of the invention, wherein the paradichlorobenzene based air freshener comprises combination of one or more vaporizable perfume or fragrance additives evenly dispersed throughout said paradichlorobenzene based air freshener.
In accordance with another embodiment of the invention, wherein the paradichlorobenzene based air freshener comprises one or more vaporizable perfume or fragrance additives selected from a group consisting of synthetic fragrances, natural essential oils, aromatic plant extracts such as resins, resinoids, balsams, tinctures and/or combination thereof.
In accordance with another embodiment of the invention, wherein the paradichlorobenzene based air freshener comprises a suitable polymer said polymer may be selected from polyamide polymers.
In a preferred embodiment of the invention, wherein said polyamide polymer may be Ethylenediamine/hydrogenated dimer dilinoleate copolymer bis-Di-C14-18 alkyl amides.
In another aspect of the invention, wherein said paradichlorobenzene may be in the range of 92-98.9% w/w and most preferably in the range of 92.5-98.7% w/w.
In accordance with an embodiment of the invention, wherein said paradichlorobenzene based air freshener comprises one or more vaporizable perfume or fragrance additives in the range of 0.8-5% w/w.
In another aspect of the invention, wherein said paradichlorobenzene based air freshener comprises suitable polyamide polymer in the range of 0.3-2.5% w/w.
In yet another embodiment of the invention there is provided paradichlorobenzene based air freshener, wherein said paradichlorobenzene based air freshener optionally comprises of thickening agents.
In a preferred embodiment of the invention, wherein the thickening agents may be selected from polyol alkoxy esters or any other suitable thickening agents.
In accordance with another embodiment of the invention, wherein said paradichlorobenzene based air freshener may take the form and shape of a solid pellet, a block, a tablet, powder, granule, flake or any other suitable form and shape.
In accordance with another embodiment of the invention there is provided a method of producing a paradichlorobenzene based air freshener with polymer having high fragrance content. The method comprises:
a. Melting the polyamide polymer;
b. Addition of a part of paradichlorobenzene into molten polyamide;
c. Cooling of the mixture of polyamide polymer and paradichlorobenzene;
d. Addition of fragrance before solidification of mixture starts;
e. Mixing the mixture of step (d);
f. Adding the premix of step (e) to the remaining amount of paradichlorobenzene and mixing thereafter; and
g. Punching the mixture of step (f) under pressure to form paradichlorobenzene based air freshener.
In accordance with yet another embodiment of the invention, wherein the polyamide polymer is melted at temperature 60-80°C.
In accordance with yet another embodiment of the invention, wherein 5-50% of paradichlorobenzene is added to the molten polyamide polymer at 60-70°C.
In a preferred embodiment of the invention, wherein 10-15% of paradichlorobenzene is added to the molten polyamide polymer at 60-70°C.
In accordance with yet another embodiment of the invention, wherein the fragrance is added to the mixture of polyamide polymer and the paradichlorobenzene when solidification starts at 45-50°C and mixed for 5-30 minutes.
In accordance with yet another embodiment of the invention, wherein said premix is added to the remaining amount of paradichlorobenzene and mixed for 5-30 minutes.
In accordance with another embodiment of the invention, wherein said method is not limited to paradichlorobenzene, it may also be applicable to other raw materials like naphthalene, camphor etc.
BRIEF DESCRIPTION OF DRAWINGS:
The invention can be described in the terms of the following figures where-
Figure 1: Shows the comparative weight loss (in g) for the conventional paradichlorobenzene based air freshener and the paradichlorobenzene based air freshener of the present invention over 30 days
Figure 2: Shows the rating of the odor of paradichlorobenzene based air freshener of present invention given by fifteen semi-trained panelists on a 0-5 point sensory chart on 0th day or at the beginning of the sensory analysis
Figure 3: Shows the rating of the odor of paradichlorobenzene based air freshener of the present invention given by fifteen semi-trained panelists on a 0-5 point sensory chart on 20th day of the sensory analysis
Figure 4: Shows the rating of the odor of paradichlorobenzene based air freshener of the present invention given by fifteen semi-trained panelists on a 0-5 point sensory chart on 30th day of the sensory analysis.

DETAILED DESCRIPTION OF INVENTION

Discussed below are some representative embodiments of the current invention. The invention in its broader aspects is not limited to the specific details and representative methods. The illustrative examples are described in this section in connection with the embodiments and methods provided. The invention according to its various aspects is particularly pointed out and distinctly claimed in the attached claims read in view of this specification, and appropriate equivalents.
It is to be noted that, as used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a composition containing “a compound” includes a mixture of two or more compounds. It should also be noted that the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
Accordingly, the present invention provides a paradichlorobenzene based air freshener having the higher amount of one or more vaporizable perfume or fragrance evenly dispersed into paradichlorobenzene along with suitable polyamide polymers. The term “solid air freshener” is defined as an essentially homogenous dispersion, which is nonflowable and solid at room temperature. The expression of quantity in terms of "% w/w" means the percentage by weight, relative to the weight of the total solution or composition, unless otherwise specified.
The term “about,” as used herein, modifying the quantity of an ingredient in the compositions of the invention or employed in the methods of the invention refers to variation in the numerical quantity that can occur, for example, through typical measuring and liquid handling procedures used for making concentrates or use solutions; through inadvertent error in these procedures; through differences in the manufacture, source, or purity of the ingredients employed to make the compositions or carry out the methods; and the like. The term about also encompasses amounts that differ due to different equilibrium conditions for a composition resulting from a particular initial mixture. Whether or not modified by the term “about,” the claims include equivalents to the quantities. All numeric values are herein assumed to be modified by the term “about,” whether or not explicitly indicated. The term “about” generally refers to a range of numbers that a person skilled in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the term “about” may include numbers that are rounded to the nearest significant figure.
The present invention relates to a paradichlorobenzene based air freshener with high fragrance content.
The present invention relates to a paradichlorobenzene based air freshener and comprises of a fragrance component along with a suitable polymer. Paradichlorobenzene is a colorless or white crystalline solid at ambient temperature and pressure and emits a characteristic aromatic odor. When exposed to air, paradichlorobenzene slowly sublimates from a solid to a vapor state and does not dissolve easily in water, making this chemical an efficient air deodorizer and thus a highly desirable component in air fresheners, toilet and urinal blocks. Paradichlorobenzene is used to control moths, moulds and mildew. Its usefulness for these applications arises from low solubility of paradichlorobenzene in water and its relatively high sublimation rate; it sublimes readily near room temperature. Paradichlorobenzene has a strong, characteristic odor. To mask the native odor of paradichlorobenzene it is recommended to add pleasant fragrances to make it more acceptable to consumers. This paradichlorobenzene based air freshener comprises paradichlorobenzene in the range of 92-98.9% w/w and most preferably in the range of 92.5-98.7% w/w.
The paradichlorobenzene based air freshener described herein includes fragrances, which are pleasant smelling and can mask objectionable odors of the paradichlorobenzene. Suitable fragrance components in said paradichlorobenzene based air freshener may be selected from the group comprising of synthetic fragrances, natural essential oils, aromatic plant extracts such as resins, resinoids, balsams, tinctures and/or combination thereof. The paradichlorobenzene based air freshener of the present invention includes greater than 0.8% fragrance. These fragrances may be present in amounts, by weight, in the range of 0.8-5% or any range subsumed therein. A person of ordinary skill in the art will appreciate that other suitable fragrances are readily available and may be utilized in the present invention without undue experimentation.
The polyamide polymers used in the paradichlorobenzene based air freshener of present invention are water insoluble and based on tertiary amides. The polyamide is available in a solid form of 100% polyamide or as a percentage of polyamide in solvents such as, for example, mineral oil and usually about 80%. Examples of commercially available polyamides which are useful in the present invention are “SYLVACLEAR A200V” (manufactured by Arizona Chemical Comp.) or “SYLVACLEAR A2614V” (manufactured by Arizona Chemical Comp.), which are Amide-Terminated Polyamide Resins (ATPAs), “UNICLEAR 100VG” (manufactured by Arizona Chemical Comp.), which is an Ester-Terminated Polyamide Resin (ETPA) and Versamid 930 (manufactured by Cognis Deutschland GmbH & Co. KG.), which is neither an ATPA nor an ETPA, with various types of surfactants, dispersing agents, and liquid oils, and basic compositions for the transparent oil-based solid cosmetic have been selected. In a preferred embodiment of the invention, the higher dosage of fragrance into paradichlorobenzene was possible by utilizing suitable polyamide polymer viz; “SYLVACLEAR A200V” or “SYLVACLEAR A2614V” having INCI name Ethylenediamine/hydrogenated dimer dilinoleate copolymer bis-Di-C14-18 alkyl amide and one or more vaporizable perfume or fragrance additives that is evenly dispersed throughout the matrix. When used in the paradichlorobenzene based air freshener as disclosed in the present invention, the polyamide polymer is typically present in the range of 0.3-2.5% w/w.
The paradichlorobenzene based air freshener of present invention comprises 0.8-5% w/w fragrance, 92-98.9% w/w paradichlorobenzene and 0.3-2.5% w/w polyamide polymers. Optional ingredients are also contemplated to be within the scope of the present invention. These optional ingredients may include thickening agents e.g., polyol alkoxy esters (available as Crothix from Croda) or any other suitable thickening agents.
The conventional paradichlorobenzene based air freshener having fragrance in an amount below 0.8% without any polymer is prepared by the conventional technology by grinding the paradichlorobenzene and adding perfume slowly and mixing for a few minutes. The resulting mixture is punched in a suitable machine.
The product of the present invention wherein the fragrance is present in the range of 0.8-5% and having the suitable polymer present in the range of 0.3-2.5% is prepared by melting the polyamide polymer and mixing a part of the paradichlorobenzene with the molten polyamide polymer. The resulting mixture is cooled and when the solidification starts, a suitable fragrance is added. This premix is added to the remaining amount of paradichlorobenzene and mixed for few minutes. The resulting bulk is then converted into the product of suitable form and shape by punching or compressing or tableting using suitable machine. The terms “punching”, “compressing” and “tableting” can be used alternatively.
In an exemplary embodiment, the paradichlorobenzene based air freshener is prepared by melting 0.3-2.5% of polyamide polymer at a temperature of 60-80°C. To this molten mass 5-50% and more preferably 10-15% of paradichlorobenzene is added at 60°C-70°C. The resulting mixture is cooled and when the solidification starts at 45-500C, a suitable fragrance in the range of 0.8-5% is added. The mixture hence obtained is mixed for 5-30 minutes and more preferably for 5 minutes. This premix is added to 50-95% and more preferably 85-90% of paradichlorobenzene and again mixed for 5-30 minutes and more preferably for 5 minutes.
The resulting solid composition may take forms and shapes including, but not limited to: an extruded, molded or formed solid pellet, block, tablet, powder, granule, flake; or any other suitable form and shape. While the invention has been described in connection with the paradichlorobenzene based air freshener, it is not intended to limit the scope of the invention to paradichlorobenzene only. This invention may also be applicable to other raw materials like naphthalene, camphor etc.
The present invention is more particularly described in the following non-limiting examples that are intended as illustrations only, since numerous modifications and variations within the scope of the present invention will be apparent to a skilled artisan. Unless otherwise noted, all parts, percentages, and ratios reported in the following examples are on a weight basis, and all reagents used in the examples were obtained or made available from the chemical suppliers.
Examples 1-7
The raw materials are identified for each of the Examples 1-7 in Table 1 and are reflecting various products of varied masses developed by using the method of preparation provided by present invention. Each of the Examples 1-7 contains suitable fragrances such as synthetic fragrances, natural essential oils, aromatic plant extracts such as resins, resinoids, balsams, tinctures and/or combination thereof and SYLVACLEAR A200V or SYLVACLEAR A2614V as the polyamide polymer. All raw materials unless otherwise specified were mixed to form a mixture and then placed into a punch assembly wherein they were compressed to acquire a suitable form.
Table 1: Composition of the paradichlorobenzene based air freshener.
Composition
of the air freshener Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7
Mass of
the air freshener (g) 35g 100g 75g 100g 50g 50g 50g
Paradichloro
benzene
(% w/w) 98.7 98.3 94.7 92.5 99.5 98.7 98.3
Fragrance
(% w/w) 1.0 1.2 3.5 5.0 0.5 1.0 1.2
Polyamide
(% w/w) 0.3 0.5 1.8 2.5 -- 0.3 0.5

Example 8
Effect on physical parameters of paradichlorobenzene based air freshener at varied fragrance levels
The effect on the physical parameters of paradichlorobenzene based air freshener at varied fragrance levels was analyzed with respect to the leaching and its strength. The term “leaching” means sweating of fragrance on the surface of the air freshener after punching or compressing or tableting. For the conventional paradichlorobenzene based air freshener without polymer, the best results reflecting the stable behavior were obtained when the fragrance level was 0.5% w/w. No leaching was observed at the time of the punching or during the use. Moreover, this conventional air freshener survived the drop test. The “drop test” is a test used to determine the physical intactness of the paradichlorobenzene based air freshener that involves dropping the tablet in horizontal position at a height of 1.5 feet on smooth surface of cemented floor. If the tablet remains intact and does not break it passes the drop test. Negative physical behavior for conventional air freshener was observed when the fragrance level was increased beyond 0.8% w/w. This result is tabulated in Table 2.
The paradichlorobenzene based air freshener of the present invention showed the positive results reflecting the stable behavior when the fragrance level was increased beyond 0.8% w/w. The leaching effect was not observed at the time of the punching or during the use. Moreover, the physical intactness during the drop test of said air freshener remained unaltered. This result is summarized in Table 3.

Table 2: Effect on physical parameters of conventional paradichlorobenzene based air freshener at different fragrance levels

Without Polymer
Fragrance Level Tableting Leaching (at the time of tableting) Leaching (at the time of in-use) Strength (by Drop Test)
0.5% Ok No No No breakage
0.8% Ok No Yes Breakage occurs
1.0% Ok Yes Yes Breakage occurs
1.2% Ok Yes Yes Breakage occurs

Table 3: Effect on physical parameters of paradichlorobenzene based air freshener of present invention at different fragrance levels.
With Polymer
Fragrance Level Tableting Leaching (at the time of tableting) Leaching
(at the time of in-use) Strength (by Drop Test)
0.5% Ok No No No breakage
0.8% Ok No No No breakage
1.0% Ok No No No breakage
1.2% Ok No No No breakage

Example 9
Comparative weight loss (in g) for the conventional paradichlorobenzene based air freshener and paradichlorobenzene based air freshener of present invention over 30 days
The effect of the higher fragrance level and the presence of polyamide polymer on rate of sublimation of paradichlorobenzene and the rate of vaporization of the fragrance was evaluated by determining the weight loss (in g) over 30 days. The control product of example 5 and the product of present invention particularly Examples 6 and 7 have been evaluated for the same. The polyamides used were specifically, SYLVACLEAR A200V or SYLVACLEAR A2614V. Table 4 shows the compositions for 50g of conventional paradichlorobenzene based air freshener and paradichlorobenzene based air freshener of present invention used for the comparative weight loss (in g).
Table 4: Compositions for 50g of conventional paradichlorobenzene based air freshener and paradichlorobenzene based air freshener of present invention.
S. No Composition
(% w/w) Example 5 (Control) Example 6 Example 7
1 Paradichlorobenzene 99.5 98.7 98.3
2 Polyamide -- 0.3 0.5
4 Fragrance 0.5 1.0 1.2

Table 5 clearly indicates that the rate of sublimation of paradichlorobenzene and the rate of vaporization of fragrance of the paradichlorobenzene based air freshener of the present invention are uniform. It was observed that the paradichlorobenzene based air fresheners of Example 6 and Example 7 had comparable weight loss (in g) than that of the conventional paradichlorobenzene based air freshener. This comparative weight loss (in g) can be illustrated by Table 5 as under:
Table 5: Vaporization rates of paradichlorobenzene and fragrance for the paradichlorobenzene based air freshener of Examples 5, 6 and 7
Days Example 5 (Control)
Wt. loss (in g) Example 6
Wt. loss (in g) Example 7
Wt. loss (in g)
0 or at the beginning of the sensory analysis. 50.0 50.0 50.0
1 46.8 47.0 47.0
2 43.7 44.3 44.0
3 40.8 41.6 41.0
4 37.9 39.0 38.1
5 35.0 36.6 35.2
6 32.3 34.2 32.4
7 29.9 32.0 29.6
8 27.5 29.9 27.6
9 25.3 27.9 25.6
10 23.3 25.9 23.8
11 21.5 24.1 22.1
12 19.8 22.3 20.5
13 18.1 20.5 18.9
14 16.5 18.8 17.4
15 14.9 17.2 16.0
16 13.4 15.6 14.6
17 12.0 14.0 13.2
18 10.6 12.5 11.8
19 9.3 11.1 10.5
20 8.1 9.7 9.3
21 7.0 8.5 8.2
22 6.0 7.4 7.2
23 5.0 6.4 6.2
24 4.0 5.4 5.2
25 3.1 4.4 4.2
26 2.2 3.5 3.3
27 1.3 2.6 2.4
28 0.5 1.7 1.7
29 0.1 0.9 1.0
30 0.0 0.4 0.6

The relationship between the weight loss (in g) for the conventional air freshener and the paradichlorobenzene based air freshener of present invention over 30 days at 25°C and 50% humidity is graphically represented in Figure 1.
Example 10
Organoleptic Sensory Analysis
The Organoleptic Sensory Analysis was carried out by a panel of fifteen semi-trained panelists. A standard quantity of the conventional paradichlorobenzene based air freshener with 0.5% fragrance level without any polymer and the paradichlorobenzene based air freshener of the present invention with 1.2% fragrance level and consisting of polymer was used. The odor of the paradichlorobenzene based air freshener was organoleptically evaluated by fifteen semi trained panelists on the 0th day or at the beginning of the sensory analysis, 20th day and 30th day. They scored the intensity of odor on a 0-5 point scale. The scores for various odor levels for the organoleptic sensory analysis are indicated in Table 6.
Table 6: Scores for various odor levels
Score Odor level
0 No odor
1 Slight
2 Definite
3 Moderate
4 Strong
5 Very Strong

The individual ratings by fifteen semi-trained panelists are graphically respresented in Figures 2, 3 and 4 for 0th day or at the beginning of the sensory analysis, 20th day and 30th day respectively. It is clear from said figures that the odor level for the paradichlorobenzene based air freshener of the present invention remained moderate to definite till the 30th day with a score of 3 and 2 respectively.
Example 11
Method of preparation of paradichlorobenzene based air freshener of Example 7
The paradichlorobenzene based air freshener of Example 7 is prepared by melting 0.5g of the polyamide polymer at a temperature 60-80°C. To this molten mass 9.83g of paradichlorobenzene is added at 60-70°C. The resulting mixture is cooled and when the solidification starts at 45-50°C, 1.2g of suitable fragrance selected from synthetic fragrances, natural essential oils and aromatic plant extracts such as resins, resinoids, balsams, tinctures and/or combination thereof is added. The mixture hence obtained is mixed thoroughly for 5-30 minutes and more preferably for 5 minutes to avoid lump formation. This mixture was added to the 88.47g of paradichlorobenzene and the entire mixture was mixed thereafter. The bulk hence obtained was punched using a suitable machine resulting in the paradichlorobenzene based air freshener of Example 7.

,CLAIMS:We claim:

1. A paradichlorobenzene based air freshener having high fragrance content.
2. The paradichlorobenzene based air freshener as claimed in claim 1, comprising one or more vaporizable perfume or fragrance additives selected from a group consisting of synthetic fragrances, natural essential oils, aromatic plant extracts such as resins, resinoids, balsams, tinctures and/or combination thereof.
3. The paradichlorobenzene based air freshener as claimed in claims 1 and/or 2, comprising a suitable polymer.
4. The paradichlorobenzene based air freshener as claimed in claim 3, wherein polymer is selected from polyamide polymers.
5. The paradichlorobenzene based air freshener as claimed in claims 3 and 4, wherein polyamide polymer may be Ethylenediamine/hydrogenated dimer dilinoleate copolymer bis-Di-C14-18 alkyl amides.
6. The paradichlorobenzene based air freshener as claimed in preceding claims, wherein paradichlorobenzene is present in the range of 92-98.9% w/w.
7. The paradichlorobenzene based air freshener as claimed in preceding claims, wherein paradichlorobenzene is present preferably in the range of 92.5-98.7% w/w.
8. The paradichlorobenzene based air freshener as claimed in claim 2, wherein one or more vaporizable perfume or fragrance additives are present in the range of 0.8-5% w/w.
9. The paradichlorobenzene based air freshener as claimed in claim 3, wherein polyamide based polymer is present in the range of 0.3-2.5% w/w.
10. The paradichlorobenzene based air freshener as claimed in claims 1 to 9, wherein said air freshener optionally comprises of thickening agents.
11. The paradichlorobenzene based air freshener as claimed in claim 10, wherein the thickening agents may be preferably selected from polyol alkoxy esters or any other suitable thickening agents.
12. The paradichlorobenzene based air freshener as claimed in preceding claims, wherein said air freshener may take the form and shape of a solid pellet, a block, a tablet, powder, granule, flake or any other suitable form and shape.
13. A method of preparing the paradichlorobenzene based air freshener comprising the steps:
a. Melting the polyamide polymer;
b. Addition of a part of paradichlorobenzene into molten polyamide;
c. Cooling of the mixture of polyamide polymer and paradichlorobenzene;
d. Addition of fragrance before solidification of mixture starts;
e. Mixing the mixture of step (d);
f. Adding the premix of step (e) to the remaining amount of paradichlorobenzene and mixing thereafter; and
g. Punching the mixture of step (f) under pressure to form said paradichlorobenzene based air freshener.
14. The method of preparing the paradichlorobenzene based air freshener as claimed in claim 13, wherein the polyamide polymer is melted at temperature 60-80°C.
15. The method of preparing the paradichlorobenzene based air freshener as claimed in claim 13, wherein 5-50% of paradichlorobenzene is added to the molten polyamide polymer at 60-70°C.
16. The method of preparing the paradichlorobenzene based air freshener as claimed in claim 13, wherein preferably 10-15% of paradichlorobenzene is added to the molten polyamide polymer at 60-70°C.
17. The method of preparing the paradichlorobenzene based air freshener as claimed in claim 13, wherein the fragrance is added to the mixture of polyamide polymer and the paradichlorobenzene when solidification starts at 45-50°C and mixed for 5-30 minutes.
18. The method of preparing the paradichlorobenzene based air freshener as claimed in claim 13, wherein said premix is added to the remaining amount of paradichlorobenzene and mixed for 5-30 minutes.
19. The method of preparing the paradichlorobenzene based air freshener as claimed in claim 13, wherein said air freshener is based on other raw materials like naphthalene, camphor etc.