FIELD OF THE INVENTION
The present invention relates to sublimable compositions. More particularly, the
present invention relates to compositions that release perfumes/fragrances,
insecticides, anti-microbials, anti-malodor agents or combinations thereof, upon
sublimation.
BACKGROUND OF THE INVENTION
Sublimable compositions containing fragrances, m various forms, such as solid
blocks or powder are well known. For the past several decades, such fragrance
emitting compositions have often included sublimable earners, such as
paradichlorobenzene, adamantane, camphor, naphthalene,
hexamethylcyclotrisiloxane, trioxane analogues etc. and have been widely used to
prepare room aromatics, toilet room deodorants, insecticides, malodor suppressants
and control moths, molds and mildew.
A large number of sublimable compositions comprise paradichlorobenzene as the
major ingredient due to its high sublimation rate, easy availability, low cost and low
solubility in water. It finds use as a disinfectant in waste containers and restrooms and
has the characteristic objectionable odor associated with urinal cakes. Therefore, it
requires a large amount of fragrance to mask its odor. This is inconsistent with the
inability of paradichlorobenzene to entrap large amount of perfumes, because of the
resultant steep drop in its melting points. The permissible content of fragrance in the
case of paradichlorobenzene is 0.1-1.0%.
No efficient alternatives have been found, and at present the only option is to omit
paradichlorobenzene and use higher concentrations of more expensive oily liquid
perfumes, as for example, in EP0167210. However, using this option is not entirely
viable because the product is more expensive and the high concentration of the
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volatile perfumery component results in the product giving an initially very high level
of fragrance, which rapidly evaporates, thereby undesirably shortening its life-time.
It is therefore desirable to provide a sublimable composition that is free of
paradichlorobenzene and long lasting, and precludes the need to add more
concentrated and expensive perfumes.
Paradichlorobenzene free sublimable compositions are known in the art. GB-A-2 061
996 and GB-A 2 021 143 disclose paradichlorobenzene-free lavatory cleansing solid
blocks, of the in-cistern type, containing 5 to 90% of nonionic surface-active agents,
0.5 to 75% by weight of one or more binders selected from clays and water-soluble or
water- dispersible gel-forming organic polymeric materials, 0 to 35% by weight of a
perfume component, from 0 to 20% by weight of one or more germicides, fungicides
and/or chlorine release agents, which are prepared by melting the nonionic
ingredients, dispersing the remainder of the ingredients and casting the resultant
melt/dispersion into moulds. These solid blocks are unsuitable for use as lavatory rim
solid blocks due to their high gelling/swelling tendency and poor foaming properties.
US 3903022 discloses sublimable fragrance compositions, comprising a perfume in
an amount in the range from about 1-7% in powdered adamantane. The mixture was
charged into a compression molding machine and molded. Such tablets were
unsuitable as freshener blocks, as a low sublimation rate and fragrance loading made
them ineffective even in small spaces.
US 4842853 discloses a solid sublimable composition, which releases a fragrant
substance, a disinfectant or combinations thereof, in which at least a portion of the
sublimable carrier is a mixture consisting of from 10 to 90 weight percent of
hexamethylcyclotrisiloxane and from 90 to 10 weight percent of
tetramethylcyclobutanedione based on the weight of hexamethylcyclotrisiloxane and
3
tetramethylcyclobutanedione. Such tablets suffered from the drawbacks of being
fragile, low sublimation rate and fragrance loading, which made them ineffective
even in small spaces. Also, due to the high sublimation rate of the carrier material, the
entrapped fragrance oozes out in the form of liquid droplets.
In view of the above discussion, there is a need in the art for improved sublimable
compositions, having high loading capacity for additives such as perfumes,
insecticides, malodour suppressants, anti-microbials or combinations thereof, carrier
material with optimum sublimation rates, and the ability of being moulded into firm
tablets.
SUMMARY OF THE INVENTION
The present invention is broadly related to sublimable compositions and more
particularly to sublimable compositions with high additive loading ability and
optimum rate of sublimation.
In accordance with an embodiment of the invention there is provided a sublimable
composition, comprising durene and at least one additive.
In accordance with another embodiment of the invention, durene is present in an
amount in the range from 70-99.9%.
In accordance with another embodiment of the invention, the additive is present in an
amount in the range from 0.1-30%.
In accordance with another embodiment of the invention, the additive is selected from
the group consisting of a perfume, insecticide, an anti-microbial agent, an antimalodor
agent, and combinations thereof.
In accordance with another embodiment of the invention, there is provided a process
for preparing a sublimable composition, comprising the steps of (a) grinding durene
4
to obtain a powder; (b) mixing the powder and the additive to form a sublimable
composition in the form of powder; and (c) compressing the sublimable composition
in the form of powder into a sublimable solid block using a suitable compressing
machine.
DETAILED DESCRIPTION OF THE 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.
The expression of quantity in terms of "% wlw" or "%" means the percentage by
weight, relative to the weight of the total solution or composition, unless otherwise
specified. The terms "solid block" and "tablet" mean the same thing and can be used
interchangeably.
Durene, or 1 ,2,4,5-tetramethylbenzene, is an organic compound with the formula
C6H2(CH3)4. It is a colorless solid with a sweet odor. The sublimation rate of durene
which is lower than that of paradichlorobenzene adds the feature of longevity to the
product in which it is used as a carrier material. The term "carrier material" used
herein refers to a material that can entrap the additives and release them into the
5
environment upon sublimation. The term "additive" used herein refers to an
insecticide, an anti-microbial agent, an anti-malodor agent, a perfume or
combinations thereof. The term "sublimable composition" used herein refers to a
composition that contains a sublimable carrier material. The sublimable composition
may contain an additive which is released into the environment by sublimation,
mechanical dispersion, evaporation, or dissolving in water. Sublimable compositions
disclosed in the prior art suffer from drawbacks such as, too low or high rates of
sublimation, limited additive bearing ability and fragility of tablets or blocks formed
on compression. Also, according to the United States Environmental Protection
Agency, the primary exposure to 1,4-dichlorobenzene is from breathing contaminated
indoor air. Acute (short-term) exposure to 1,4-dichlorobenzene, via inhalation in
humans, results in irritation of the skin, throat, and eyes. Chronic (long-term) 1,4-
dichlorobenzene inhalation exposure in humans results in effects on the liver, skin,
and central nervous system (CNS). Additionally, the present inventors have found
that Durene has a better toxicity profile compared to 1 ,4-dichlorobenzene.
In order to overcome the aforementioned drawbacks the inventors of the present
invention have developed a sublimable composition comprising durene, and
additives. Durene 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 solid blocks. To mask the native odor of durene it is recommended to add
perfumes to make it more acceptable to consumers. Also, in order to impart additional
functionality to the sublimable compositions it is recommended to add other
additives, such as insecticides, anti-malodor agents and anti-microbial agents. The
sublimable composition of the present invention comprises durene in an amount in
the range from 70-99.9% and additives in an amount in the range from 0.1-30%.
The sublimable compositions described herein include fragrances or perfumes, which
are pleasant smelling and can mask objectionable odours. Non-limiting examples of
fragrance or perfumes that can be used in the sublimable compositions include
6
synthetic fragrances, natural essential oils, aromatic plant extracts such as resins,
resinoids, balsams, tinctures and so forth, each of which can be used individually or
in combination.
An insecticidal activity, i.e, the ability to kill insects, can be imparted to the
sublimable composition, by adding insecticides as additives. The term "insecticide"
used herein refers to any substance capable of killing insects. Non-limiting examples
of the insecticides that can be used in the present invention include organic
phosphorous insecticides, lipidamide insecticides, natural repellents, citronella oil,
natural pyrethrins, pyrethrum extract, synthetic pyrethroids, organochlorine
compounds and so forth each of which can be used individually or in combination.
Non-limiting examples of synthetic pyrethroids that can be used in the present
invention include acrinathrin, allethrin as D-allethrin, Pynamin®, benfluthrin,
bifenthrin, bioallethrin as Pynamin Forte®, S-bioallethrin, esbiothrin, esbiol,
bisoresmethrin, cycloprothrin, cyfluthrin, beta-cyfluthrin, cyhalothrin, lambdacyhalothrin,
cypermethrin, alpha-cypermethrin, beta-cypermethrin, cyphenothrin,
deltamethrin, empenthrin, esfenvalerate, fenpropathrin, fenvalerate, flucythrinate,
taufluvalinate, kadethrin, permethrin, phenothrin, prallethrin as Etoc®, resmethrin,
tefluthrin, tetramethrin, tralomethrin, metofluthrin, transfluthrin and so forth, each of
which can be used individually or in combination. Non-limiting examples of suitable
organochlorine compounds are hexachlorocyclohexane and its isomer known under
the name lindane, chlordane and heptachlor. Non-limiting examples of suitable
organophosphorus compounds are dichlorvos, carbophenothion methyl,
trichlormetafos-3, fenchlorphos, demethion, phorate, demetomnethyl, naled or
dibrom, chlorothion, thiometon, demeton, chlormephos, pirofos, acetofos-methyl,
bromophos, dichlorfenthion, acetofos, mevinphos and so forth.
An anti-microbial activity can be imparted to the sublimable compositions by adding
various anti-microbial agents as additives. The term "anti-microbial agent" used
herein refers to any substance that can kill micro-organisms such as bacteria, fungi
7
and viruses. Non-limiting examples of the anti-microbial agents that can be used in
the present invention include organic nitrogen-sulfur compounds, a quaternary
ammonium compound, a phosphoric ester compound, a quaternary ammonium salt of
an alkyl phosphoric acid ester (for example, cetyl dimethyl ammonium chloride); an
organic antimicrobial agent such as benzalkonium chloride, alkyl aryl sulfonate, halo
phenol, mercuric phenyl acetate; polyphenols, an inorganic compound containing a
metal ion, and so forth, each of which can be used individually or in combination.
A deodorant property may be imparted to the sublimable composition by adding antimalodor
agents as additives. Non-limiting examples of anti-malodour agents used in
the present invention includes zeolites, activated carbons, zinc salts, zinc oxides,
cyclodextrins, fatty alcohol esters, aliphatic aldehydes (ClO, Cll, and C12), zinc
ricinoleate actives, benzaldehyde, soyethyl morpholiniurn ethosulfate,
Metazene®(Dodecyl methacrylate), Meelium® (a blend of polyhydroaromatic
sulfonates), glycol selected from the group consisting of triethylene glycol (TEG),
dipropylene glycol, propylene glycol, triethanolamine and so forth, each of which can
be used individually or in combination.
The durene based sublimable composition comprising additives in an amount in the
range from 0.1-30% w/w was prepared by grinding the required amount of durene to
a powder and mixing the additive to form a sublimable composition in the form of a
powder. The resulting sublimable composition in the form of a powder can be
transformed into a solid block by compressing it with a tableting machine. The solid
block may be of any suitable shape and size.
The durene based sublimable compositions may be used for suppressing or masking
malodours in restrooms, cars, locker rooms, lunch rooms, laundry areas, hampers and
any other enclosed space susceptible to malodour.
The present invention is more particularly described in the following non-limiting
examples that are intended as illustrations only, since numerous modifications and
8
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 1-13.
The sublimable compositions of the present invention can be used for disseminating
fragrances, anti-microbial agents, insecticides, and anti-malodour agents. Table 1, 2,
3, 4 and 5 list the constituents and their amounts to be used in the sublimable
compositions. The unit of each value is percent by weight.
Table 1. Constituents of sublimable compositions in the form of an air freshener
(additive is a fragrance).
Example Durene(% w/w) Fragrance(%w/w) Form
1 99 1 Solid block
2 98 2 Solid block
3 97 3 Solid block
4 96 4 Solid block
5 95 5 Solid block
6 80 20 Powder
7 70 30 Powder
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Table 2. Constituents of sublimable compositions in the form of lavatory cleansing
solid blocks of the in-cistern type and rim solid blocks. (additive is a combination of a
fragrance and anti-microbial agents).
Example Durene Fragrance Surfactants Benzalkoni Form
urn chloride
(% w/w) (% w/w) (%w/w)
(% w/w)
.
8 95 3 1 1 Solid block
9 90 5 3 2 Solid block
Table 3. Constituents of sublimable compositions in the form of a urinal block.
Example Durene . Fragrance Benzalkonium
chloride(% w/w) Form
(%w/w) (%w/w)
10 95 4 1 Solid block
11 95 3 2 Solid block
Table 4. Constituents of sublimable compositions in the form of insecticidal tablets.
(additive is an insecticide).
Example Durene Transfluthrin Form
(% w/w) (% w/w)
12 95 5 Solid block
10
Table 5. Constituents of sublimable compositions in the form of mal odour neutralizer
tablets. (additive is a combination of a fragrance and anti-malodour agent).
Example Durene Metazene Fragrance Form
(% w/w) (% w/w) (%w/w)
13 95 3 2 Solid block
Process for preparing the sublimable compositions
Durene was ground into a powder and mixed with an additive to obtain the
sublimable composition in the form of a powder. The sublimable composition in the
form of a powder was further transformed into a solid block by compressing it in a
suitable compressing machine such as a tableting machine. Table 1, 2, 3, 4 and 5 list
the constituents and their amounts to be used in the sublimable compositions. The
unit of each value is percent by weight.
Effect of additive (fragrance) concentrations on the physical characteristics of
the tablet of the sublimable compositions.
The mixture of durene powder and additive (fragrance) was punched using a tableting
machine into a tablet or a solid block of desired shape. The term "tableting machine"
used herein refers to a machine which compresses the ingredients of a mixture into a
suitably shaped solid block. No leaching of the additive was observed at the time of
the punching or during use of the tablet. The term "leaching" means sweating of
additive (fragrance) on the surface of the tablet after punching or compressing or
tableting to a solid block. Moreover, the tablet survived the drop test. The "drop test"
is a test used to determine the physical strength of the tablet that involves dropping
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the tablet in a horizontal position from a height of 1.5 feet onto the smooth surface of
a cemented floor. If the tablet remains intact and does not break, it passes the drop
test. The results are presented in Table 6.
Table 6: Effect of additive concentration on the physical characteristics of
tablets.
Leaching Leaching
Strength
Example Fragrance Tableting (@Time of (@Time
(By
Punching) of Use) Drop
Test)
1 1.0% Yes No No Passes
2 2.0% Yes No No Passes
3 3.0% Yes No No Passes
4 4.0% Yes No No Passes
5 5.0% Yes No No Passes
In order to compare the moulding ability of para-dichlorobenzene and durene, 5 g of
perfume was mixed with 95 g of para-dichlorobenzene and durene. It was observed
that the mixture of durene and perfume could be easily moulded into solid blocks or
tablets, whereas the mixture of para-dichlorobenzene and perfume failed to provide a
firm solid block or tablet.
Weight loss in grams (g) of the tablet or solid block of Example 5 weighing 30 g
over a period of 45 days.
The rate of sublimation of the sublimable composition comprising a fragrance as
additive was determined by recording the weight loss (in g) over 45 days. The
experiment was carried out at ambient temperature (25±3 °C, relative humidity =
50±5% ). Table 7 presents the rate of vaporisation of the sublimable composition in
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terms of the final weight of the solid block on a particular day over a period of 45
days.
Table 7: Sublimation rates of the sublimable composition of Example 5.
Day Final weight of
the solid block
1 30.00
10 20.577
20 12.369
30 5.688
40 1.272
45 0.12
Organoleptic Analysis
The odor of the sublimable composition containing 5% fragrance was
organoleptically evaluated by ten semi trained panelists on the I '1 day or at the
beginning of the sensory analysis, 20th day and 40th day. They scored the intensity of
odor on a 0-5 point scale (Table 8). The scores given by the panelists for various odor
levels in the organoleptic analysis are presented in Table 9.
Table 8: Scores for various odor levels
Score Odor level
0 No odor
I Slight
2 Definite
3 Moderate
4 Strong
5 Very Strong
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Table 9: Scores for various odor levels
Evaluator Durene with 5% Durene with 5% Durene with 5%
fragrance on l't fragrance on 20th fragrance on 40th
day day day
Panelist-! 5 4 3
Panelist-2 5 5 4
Panelist-3 5 4 3
Panelist-4 5 4 3
Panelist-S 5 4 4
Panelist-6 5 4 3
Panelist-? 5 5 4
Panelist-S 5 4 3
Panelist-9 5 5 4
Panelist-10 5 4 3
Average
5 4.3 3.4
Score
It is clear from the organoleptic analysis that the odor level of the sublimable
composition of present invention remained moderate to strong till the 40th day.
While particular embodiments of the present invention have been illustrated and
described, it would be obvious to those skilled in the art that various other changes
and modifications can be made without departing from the spirit and scope of the
invention. It is thereof intended to cover in the appended claims such changes and
modifications that are within the scope of the invention.
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We claim:
1. A sublimable composition, comprising durene and an additive.
2. The sublimable composition as claimed in claim I; wherein durene is present
in an amount in the range from 70-99.9% and the additive is present in an
amount in the range from 0.1-30%.
3. The sublimable composition, as claimed in claim 2, wherein the additive is
selected from the group consisting of a perfume, insecticide, an anti-microbial
agent, an anti-malodor agent, a surfactant and combinations thereof.
4. The sublimable composition as claimed in claim 3, wherein the insecticide is
selected from the group consisting of organic phosphorous insecticides,
lipidamide insecticides, natural repellents, citronella oil, natural pyrethrins,
pyrethrum extract, synthetic pyrethroids, organochlorine insecticides, and
combinations thereof; wherein the synthetic pyrethroids are selected from the
group consisting of acrinathrin, allethrin as D-allethrin, Pynamin®,
benfluthrin, bifenthrin, bioallethrin as Pynamin Forte®, S-bioallethrin,
esbiothrin, esbiol, bisoresmethrin, cycloprothrin, cyfluthrin, beta-cyfluthrin,
cyhalothrin, lambda-cyhalothrin, cypermethrin, alpha-cypermethrin, betacypermethrin,
cyphenothrin, deltamethrin, empenthrin, esfenvalerate,
fenpropathrin, fenvalerate, flucythrinate, taufluvalinate, kadethrin, permethrin,
phenothrin, prallethrin as Etoc®, resmethrin, tefluthrin, tetramethrin,
tralomethrin, metofluthrin, transfluthrin and combinations thereof.
5. The sublimable composition as claimed in claim 3, wherein the anti-microbial
agent is selected from the group consisting of organic nitrogen-sulfur
compound, a quaternary ammonium compound, a phosphoric ester compound,
a quaternary ammonium salt of an alkyl phosphoric acid ester (for example,
cetyl dimethyl ammonium chloride); an organic antimicrobial agent such as
benzalkonium chloride, alkyl aryl sulfonate, halo phenol, mercuric phenyl
15
acetate; polyphenols, an inorganic compound containing a metal ion, and
combinations thereof.
6. The sublimable composition as claimed in claim 3, wherein the anti-malodor
agent is selected from the group consisting of natural essential oils, fragrance,
zeolites, activated carbons, zinc salts, zinc oxides, cyclodextrins, fatty alcohol
esters, aliphatic aldehydes (CIO, C11, and C12), zinc ricinoleate actives,
benzaldehyde, soyethyl morpholinium ethosulfate, Metazene®( Dodecyl
methacrylate), Meelium® (a blend of polyhydroaromatic sulfonates), glycol
selected from the group consisting of triethylene glycol (TEG), dipropylene
glycol, and propylene glycol, triethanolamine and combinations thereof.
7. A process for preparing a sublimable composition as claimed in claims I to 6,
comprising the steps of:
(a) grinding durene to obtain a powder;
(b) mixing the powder and the additive to form a sublimable composition in
the form of a powder.
8. The process for preparing a sublimable composition as claimed in claim 7,
further comprising compressing the sublimable composition in the form of a
powder into a sublimable solid block using a suitable compressing machine.