Note: Descriptions are shown in the official language in which they were submitted.
Z0021;~6
951-219 CIP
DEVICE FOR DISPENSING VOLATILE FRAGRANCES
KGROUND OF THE INVENTION
CR~SS-REFERENCE TO R~ATED AP~CATION
This application is a continuation-in-part of my
copending U.S. Patent Application S.N. 787,069 filed October
15, 1985.
Field of the I~ Qn
The invention relates to an article of manufacture for
the slow release of a volatile fragrance composition.
Brief D scription of the Prior Art
Articles of many types for the controlled release of
volatile compositions such as odorants or deodorants, to the
environment, are well known in the art. However, articles
which have heretofore been disclosed suffer from various
disadvantages, especially with respect to performance.
Ideally, an article for dispensing a volatile fragrance
composition should dispense the composition unchanged at an
essentially constant rate over an extended period of time, to
provide an effective level of the fragrance in the
environment, up to the time when the volatile composition
contained within the article is depleted. This desirable
property is termed a "linear release".
The so-called gel-type deodorizer dispensers in which a
fragrance is dispersed in a water based gel are known and
generally useful in that they provide acceptable levels of
deodorant to the air environment. Release may be the desired
linear release, but many dispensors of this type do not
provide a linear release. Also, the gel-type dispensers
suffer from the disadvantage that the lifetimes for fragrance
release are relatively short, typically on the order of one
or two weeks; due to rapid evaporation of water and fragrance
from the gel formulation. An additional disadvantage of the
gel-type dispensers is that only select frayrance
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compositions, which are compatible with the water-based gels,
can be used in the gel formulations.
Articles comprised of a volatile dispersed in various
polymeric resin substrates such as polyamides, ethylene-vinyl
acetate copolymer, cross-linked methacrylate derivatives and
the like have also been described in the prior art
literature. These articles suffer from the disadvantage that
levels of fragrance output are frequently too low to be
effective for all purposes. These articles also generally
provide a non-linear release of fragrance, that is, the level
of the fragrance output is typically high during the initial
period of use but then drops off within a short period of
time. An additional disadvantage of these articles is that
many volatile fragrances are incompatible with the polymer
substrates. This frequently results in sweating of the
article surface, a situation where beads of fragrance
material appears on the surface of the polymer substrate. A
further disadvantage of the articles in which fragrances are
dispersed in a solid polymer is that liquid fragrances must
either be admixed with the polymer by melt blend~ng at
relatively high temperatures or mixed with the monomer prior
to carrying out the polymerization reaction. In both ?
instances, substantial degradation o~ fragrances may occur.
Examples of polymeric articles of the aforementioned types
are described in U.S. Pat. Nos. 4,095,031; 4,411,8S5;
3,926,655; 4,184,009 and Canadian Pat. No. 1,099,429. Also
illustrative of such articles is that described in Japanese
Patent Application No. 82-40,558. This latter reference
describes a fragrant, rubber-liXe molding material, formed by
dispersing a fragrance in a silicone rubber and then carrying
out a cross-linking reaction with an organometal salt. The
articles suffer from the disadvantage that severe sweating of
- the silicone rubber occurs at even moderate loadings of
volatile substances due to incompatibility of the silicone
polymer and the fragrance.
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Wick-type deodorizers have also been described in the
prior art. Release of the deodorant may at times be linear.
Although these reservoir-type systems are effective under
limited conditions, the dispensers are generally
objectionable in appearance. The wicks are sometimes prone
to clogging and generally require deodorants which are
suitable for water-based formulations.
The U.S. Patent No. 4,161,283 describes a fragrance-
dispensing pouch comprised of a fragrance-containing
reservoir enclosed by an outer wall made of a fragrance
(gas) permeable film, heat sealed to an impermeable inner
wall. This device suffers from the disadvantage that it is
not self-supporting and therefore cannot be conveniently
located where desired. It is al~o difficult t~ manufacture
and articles of this type cannot be made into a variety of
desirable shapes. More importantly the fragrances which are
desirably used in "air freshener" type devices are generally
a complex blend of a large number of components having a wide
variety of volatilities. As mentioned above, ideally there
should be a uniform discharge of the total blend components
over the entire li~e of the device, so as to emit the
complete fragrance. The emission of the unchanged blend of
ingredients, i.e., linear emission, has heretofore been
difficulat to obtain with the pouch type of prior art
devices. The fragrance when exposed to the air within the
pouch w~ll break down into its individual volatile components
with the most volatile component passing through the
reservoir wall without the remaining volatiles. Then in
sequence, each of the next more volatile components
vaporizes and passes through the reservoir wall. The serial
release of the components of the fragrance composition may
result in the observed fragrance having a substantially
different odor over its intended life rather than a linear
release, i.e., a constant and unchanging fragrance over a
period of time. The problem of ~erial emission of the
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components of the fragrance rather than linear emission is
encountered with all o~ the thin film gas permeable materials
typica~ly used in prior art devices, such as is described in
U.S. Patent 2,766,066 (Hopson et al.).
A dispenser is described in the U.S. Patent 4,161,283 to
Hyman which functions by molecular diffusion of a liquid
volatile composition through a generally non-porous
polymeric resin wall. This type of fragrance dispenser
suffers from the disadvantage that all ingredients in a
complex fragrance composition do not have the same molecular
structure and will not diffuse through the polymeric resin
walls at the same rates. The composition is changed as it is
released, i.e., a non-linear release.
Also, it is generally well-Xnown that the thicker the
film of a polymer, the lower is the rate of gas or liqiuid
permeability through the film. Accordingly, in order for
polymer films such as polyethylene or polyvinyl chloride to
have adequate permeabiilty the film has to be either very
thin or made mechanically porous with holes or like
perforations; see U.S. Patent 2,766,066, supra.
The articles o~ the present invention are particularly
useful for the containment of a l~guid form of a volatile
fragrance composltion and the sustained, slow release of a
volatilized form of the compos~tion to the atmosphere.
We have found that silicone rubbers have a unique
property which makes relatively thick sections especially
useful in air freshener devices. Silicone rubbers in
addition to behaving like thin films of other polymers with
regard to gas permeability, in relatively thick films, charge
up or load up with the liquid fragrance composition,
unchanged in regard to the relative amounts of each of the
components in the fragrance composition. In other words, the
liquid composition permeating tha rubber will have the same
ingredient make-up as the liquid composition held in the
device's reservoir. Once the thick film of the silicone
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rubber material is charged up the unchanged liquid
composition travels through and is evaporated in toto from
the outer surface of the silicone rubber. It is important
to note that the relative thickness of the silicone rubber,
once it is thicker than the point where there is any
substantial amount of gas permeability, does not affect the
operation of the device except with regard to the time
required to allow for ~ully charglng of the entire thickness
of the silicone rubber. The only factor which appears to have
any effect on the dispensing of the fragrance material from
an article of the invention is the amount of outer surface
area which is exposed to the ambient air.
A difference between many of the prior art articles and
the present invention is that the articles of the invention
do not rely on gas permeation through a thin or porous
membrane. Instead, liquid penetration as a uniform mixture
through a relatively thick silicone rubber body provides
linear release of fragrance composition ingredients.
Silicone rubbers have ~een described as functioning as
reservoirs for the slow release of liquids to marine
environments; See for example the U.S. Patent 3,426,473 to
Cardarelli et al. issued on February 11, 1969. Also,
impermeable housings ~upported on leg3 have been suggested to
contain deodorants for dispensing; see U.S. Patent 4,096,994
(Bryson).
SUMMARY OF THE INVENTION
The invention comprises an article for dispensing a
volatile fragrance composition to the atmosphere, which
comprises;
A. an open-ended hollow body of a material which is
substantially impermeable to said volatile composition;
B. a l~quid volatile fragrance composition contained in
the hollow of said body:
C. a silicone rubber closure having first and second
surfaces, and a body between the surfaces, mounted in the
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open end of the hollow body and having the first surface in
direct contact with the liquid volatile composition, and the
seco~d surface in contact with air outside of said body,
said closure being permeable to said composition in a liquid
form, said closure being substantially impermeable to the
volatile composition in a volatilized form;
D. a base attached to the open end of the hollow body,
said base including means to allow circulation o~ air below
the silicone rubber closure, in contact with the second
surface of the closure:
said body being penetrable by said composition in a
liquid form, at a rate less than the rate of volatilization
of the liquid volatile composition as it reaches the second
surface of the hollow body under ambient temperature and
pressure conditions.
An advanta~e of the invention is that any volatile
fragrance composition, including expensive perfume
compositions, may be contained and slowly released from the
article without any alteration of the comps~ition or released
aroma. The articles of the invention may be used for
dispenslng fragrances over a long period of time, as for
example, several weeks or months. This device is
advantageously used a~ an air freshener.
Another advantage of the invention is that the article
reservoirs may be refilled with either the same or another
volatile fragrance composition after the original charge has
been depleted. This reusability is attractive to many
consumers, due to real and perceived cost savings. It is
also an attractive feature to the supplier of the fragrance
composition because it encourages resale of their composition
to the original purchaser of the dispenser article.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of an open-ended hollow
body to which is affixed by compression to the open end of
the hollow body a disc made of silicone rubber.
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Figure 2 is a cross-sectional view of the device
depicted in Figure 1, which shows the reservoir for
con1:aining the volatile substance, the silicone rubber disc,
and a screw cap which functions to tightly hold the s~licone
rubber disc in place and also functions as a base through
which air is allowed to circulate by virtue of the base
design.
Figure 3 is a view as in Figure 2, but with the device
inverted.
DETAILED DESCRIPTION OF THE PREFERRED
EMBODIMENTS OF ~HE INVENTION
Referring first to Fig. 1, a perspective view of an
embodiment device 10 of the invention is seen. The device 10
comprises a cylindrical body 12 which may be fabricated from
any conventional material such as metal, glass, synthetic
polymeric resin and like materials which are impermeable to
the volatile composition to be contained and dispensed. The
body 12 ha a closed end 14 and an open end 16 resting on a
base cap 18 which is supported by legs 20 about the lower
periphery of the base cap 18.
Referring now to Fig. 2, a view along lines 2-2 of Fig.
1, further details of the device 10 may be seen including a
chamber 22 defined by the walls of the body 12 and the ends
14, 16. The chamber 22 is filled or partial.ly filled with a
liquid volatile composition 24. A silicone rubber disc 26 is
affixed to the open end 16 of the hollow body 12 and held
tightly in place by the cap 18 which serves as a base for
the device 10 and is also designed to allow circulation of
air below the silicone rubber disc 26, batween legs 20.
A silicone rubber is herein defined as a cross-linked
silicone elastomer, preferably of the type vulcanized at room
temperature (~TV) or at elevated temparatures (HTV). Such
silicone rubbers are well known, as are methods of their
preparation; see for example the descriptions given in the
U.S. patents 3,664,997; 3,674,738; 4,1~0~642, 4,216,140; and
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4,419,484, all of which are incorporated herein by reference
thereto. Dimethyl siloxanediol with silicone resin or alkyl
sllicate as cross-linking agents are advantageously used.
Generally, fillers such as silica, calcium carbonate,
titanium oxide, and the like may be added to the polymer.
The filler materials provide rigidity. Mica fillers can also
be used to control porosity of the silicone rubber. Higher
mica contents reduce vapor and gas transmis~ion rates.
One example of a preferred silicone rubber used in the
invention is the commercially available Dow Corning 3110 RTV
silicone rubber. This material may be cross-linked at room
temperature with Dow Corning RTV catalyst No. 4.
We have found that the sil~cone rubber disc 26 thickness
is a limiting variable, in that relatively thick walls, as
thick as about 1-2 mm to about 5 mm, will give uniform and
high rates of release of volatile ~ragrance composition 24.
Thinner walls tend to allow the passage of gases, including
the volatilized form of the fragrance composition (when the
device 10 is inverted during non-use as described below). As
described above, this is undesirable, and may result in a
non-linear dispensing of the fragrance composition.
In actual use the liquid fragrance composition 24 is
brought into contact with the thick body of silicone rubber
26 as shown in Figure 2. The uniform mixture of the
fragrance composition 24 charges up the silicone rubber disc
26 and travels to the outer surface where it can be exposed,
unchanged, to the air. A uniform mixture of the fragrance
composition constantly volatilizes from the outer surface and
is repleniehed with fre~h liquid fragrance composition 24
from within the body of the silicone rubber disc 26. It has
been found that over the course of the entire use of a device
10 having the thick silicone rubber disc 26 that there is a
uniform linear emission of the fragrance composition.
It will be appreciated that the liquid porosity of the
silisone rubber disc 25 is a factor to be adjusted for in
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relation to the fluidity and penetration of the fragrance
composition 24 and the rate at which it will transfer across
the wail of disc 26. If the rate of travel is too fast, the
liquid will accumulate on the outer surface of disc 26 faster
than volatilization occurs. As mentioned above, this is a
problem with many of the prior art devices. To avoid this,
some trial and error testing may be necessary for specific
combinations of silicone rubber (thickness and porosity) and
fragrance compositions. In general however the silicone
rubber may be selected from those having a water vapor
transmission rate at 38- C, under a 90 percent room humidity
of from 5 to 50 gms/24 hours/m2 in a 70 mil. thick section
(as determined by ASTM test method E-96-66, Condition E) and
a gas ~N) permeability coefflcient of
at 23C. and atmospheric pressure.
Figure 3 is a cross-sectional side elevation of the
embodiment device 10 of the invention shown in an inverted
position. In this position the fragrance composition 24 is
removed from conta~t with the disc 26. Since disc 26 is
substantially impermeable to a volatilized form of
composition 24, the device 10 is "switched off" and does not
dispense the fragrance composition 24.
While there have been shown and described preferred
embodiments of a device 10 for dispensing volatile
compositions in accordance with the invention, it will be
appreciated that many changes and modificati~ns may be made
without departing from the spirit of the invention. For
example, the device 10 may be packaged for transportation and
storage before use within an impermeable barrier layer or
film such as a metal foil to further inhibit dispensing of
the contained composition 24 prior to the time when release
is desired.
The device 1~ is particularly useful for the dispensing
of complex fragrance composition 24. Fragrances which may
be included in the complex compositions 24 are represented by
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natural essential oils such as lemon oil, mandarin oil, clove
leaf oil, petitgrain oil, cedar wood o~l patchouli oil,
lavandin oil, neroli oil, ylang oil, rose ahsolute or jasmin
absolute; natural resins such as labdanum resin or olibanum
resin; single perfumery chemicals which may be isolated from
natural sources or manufactured synthetically, as for example
alcohols such as geraniol, nerol, citronellol, linalool,
tetrahydrogeraniol, betaphenylethyl alcohol, methyl phenyl
carbinol, dimethyl benzyl carbinol, menthol or cedrol;
acetates and other esters derived from such alcohols-
aldehydes such as citral, citronellal, hydroxycitronellal,
lauric aldehyde, undecylenic aldehyde, cinnamaldehyde, amyl
cinnamic aldehyde, vanillin or heliotropin; acetals derived
from such aldehydes; ketones such as methyl hexyl ketone, the
ionones and the methylionones; phenolic compounds such as
eugenol and isoeugenol; synthetic musks such as musk xylene,
musk k~tone and ethylene brassylate and the like.
Generally, the fragran~es a~ represented above are
~ompounded in mixture~ with perfumery acceptable carriers to
obtain the compositions 24.
Perfumery acceptable carriers are well known and are
represented by a volatile liquid, such as a non-toxic alcohdl
(e.g. ethyl alcohol), a non-toxic glycol (e.g. 1,2-propylene
glycol) and the like.
The compositions 24 as paxt of the articles of the
invention may be prepared by a simple, homogeneous admixture
of the carrier and the fragrance ingredient or ingredients.
The following example describes the manner and process
of making and using the invention and sets forth the best
mode contemplated by the inventor f~r carrying out the
invention but are non-limi~ing of the invPntion. All parts
are by weight unless otherwise stated. Where reported, the
following test methods are employed: Tensile strength, ASTM
test met~od D-638; elongation, ASTM test method D-638; Shore
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A hardness, ASTM test method D-2240: moisture vapor
transmission rate, ASTM test method E-96-66 (condition E).
~xamEl~
There is mixed with 480 parts of silanol end-stopped
dimethylpolysiloxane of 4200 centipoise viscosity at 25C,
120 parts of trimethylsiloxy end-stopped, silanol end-stopped
polysiloxane oil, and 18 parts of a cyclicsiloxane treated
fumed silica and 480 parts of 160 me~h mica which is treated
with 4% by weight of stearic acid. To 100 parts of the above
composition there is added 10 parts of a catalyst composition
prepared by mixing 102 parts of a vinyl terminated
dimethylpolysiloxane of 3,000 cps at 25-C, 120 parts of
CaCo3, 48 parts of gamma aminopropyltriethoxysilane, 24 parts
of partially hydrolyzed ethyl silicate and 3.~ parts of
dibutyl tin dilaurate.
Sample sheets of the compositions which have cured for
24 hours at 25~C give the following physicals and moisture
vapor transmission rate (MVTR):
Tensile Strength psi: 330
Elongation %: 70
Shore A Hardness: 62
MVTR - 8.25 grams/M2 on sheet 74 mils thick.
A container article as shown in the accompanying
drawing of figure 1 is molded from a polystyrene and closed
with a s~licone rubber disc molded from the above described
silicone rubber, having a minimum wall thicknes~ of about 5
mm and a container capacity of about 25 gms of a liquid
fragrance
composition prepared by simple admixturP of the following
ingredients.
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phenyl ethyl alcohol extra 27.00
linalol pure 10.00
benzyl acetate 14.00
lilestralis 7.00
amyl cinnamic aldehyde 7.00
alpha terpineol 10.00
gamma methyl ionone 5.00
aldehyde C11 - lenic 0.50
coumarin crystals 3.00
terpinyl acetate 1.50
para-tert-butyl-cycloxyl acetate 10.00
diethyl phthalate 5.00
100. 00
The fragrance composition, which has a woody, ambre
character, is charged to the device 10 and the device is
placed in an open room for a period of about 6 weeks. At
that time, a second device is charged with a freshly
prepared fragrance composition as de~cribed above. A panel
of odor analysts is assembled and asked to evaluate the odor
emanating from the two containers and from the freshly
prepared composition. A ma;ority of the panel will agree
that they cannot distinguish the three sources of fragrance.
In perfume compositions, it i~ the individual components
which contribute their particular olfactory characteristics.
However, the overall sensory effect of the perfume
composition will be at least the sum total of the effects of
each of the ingredients. It can be concluded that the
volatilized and dispensed fragrances described in this
example are unchanged in their passage to the atmosphere.
There is a linear release.
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