GB2584715A

GB2584715A - Air freshener

Info

Publication number: GB2584715A
Application number: GB1908495.3A
Authority: GB
Inventors: Dix Robert; Moulden Michael
Original assignee: Vectair Systems Ltd
Current assignee: Vectair Systems Ltd
Priority date: 2019-06-13
Filing date: 2019-06-13
Publication date: 2020-12-16
Anticipated expiration: 2039-06-13
Also published as: GB201908495D0; GB2584715B

Abstract

An air freshener comprising a container impregnated with a first fragrance capable of evaporating from the exposed surfaces of the container, and a gel composition comprising a second scent in contact with the surface of the container. The gel composition evaporates from its exposed surfaces, resulting in contraction and thereby exposing at least part of the surface of the container, allowing the first fragrance to be diffused more as the gel composition diminishes. The gel composition may be located in a concave recess within the container. The container may be a cylinder surrounding the gel composition and may be open at one end. There may be a plurality of apertures extending radially through the cylindrical wall of the container, and the gel composition may at least partially extend into said apertures. The cylinder may be composed of an ethylene-vinyl-acetate copolymer. The first fragrance, the second fragrance, or both fragrances may be oil based, and the first and second fragrances may be different.

Description

Air Freshener

S

FIELD OF THE INVENTION

The present invention relates to air fresheners.

1-10 BACKGROUND ART

The use of air fresheners to create a more pleasant ambience is well known. Generally, these consist of a carrier impregnated with a pleasant fragrance that can evaporate over time, thus masking or replacing an unpleasant odour in its vicinity. Others employ compounds that absorb or neutralise odours, and/or compounds that include, or consist of, compounds having an insect repellent property. For convenience, we will refer to all three types of compounds as "fragrance". Many suggestions have been made over the years as to delivery mechanisms for the fragrance, including simple bowls of exposed fragrance-infused liquids, solid blocks of infused material, containers adapted to deliver metered doses of fragrance such as by a periodically-activated aerosol spray or the like.

Longer-lasting fragrance dispensers primarily consist of a housing within which a reservoir of fragrance is held, together with a wick to gradually evaporate the fragrance into the surrounding air. The reservoir is often defined within a cartridge that can be removed from the housing when exhausted and replaced. An example can be seen in our earlier application EP-A-2113259. These kinds of dispensers do however need to retain a quantity of fragrance, often in liquid form, which can be unpleasant if it escapes from the reservoir and is often an irritant. However, their long life between service intervals makes them attractive in commercial settings such as offices and washrooms.

Attempts to alleviate the problem have been through the use of viscous gels which are less likely to leak from a damaged reservoir than a fluid. However, the aromatic oils and emulsifiers used to ensure homogenous mixing of the oils in the aqueous solution often disrupt the gelling agents such that it is challenging to make a semi-solid gel with a high concentration of perfume. Furthermore, physical contact with the gel can result in the oil being released into the skin, potentially resulting in irritation.

An alternate fragrance delivery method is through the use of a ceramic surface impregnated with a fragrance. The porous nature of ceramics enables them to readily take up a fragrance and then later release it into the environment. They have the advantage that the ceramic surface will not deposit significant amounts of oil onto surfaces touching them, so that they may be safely be picked up with bare hands.

Our earlier application W02015/067505 sought to address the problem of olfactory fatigue (also known as fragrance fatigue), i.e. a reduced ability to distinguish a fragrance after a prolonged exposure to that fragrance. An explanation of the mechanism of olfactory fatigue (or "olfactory adaptation") can be found at http://en.wikipedia.org/wiki/Olfactory fatigue. We proposed a dispenser comprising a ceramic outer shell impregnated with an evaporable liquid fragrance, and having an internal recess containing a fragranced gel, the gel fragrance being different to the liquid fragrance, and contained within a closed disposable container.

SUMMARY OF THE INVENTION

The present invention seeks to provide a convenient and effective means for delivering a fragrance over an extended period of time. It therefore provides an air freshening apparatus, comprising a container infused with a first fragrance capable of evaporating from the exposed surfaces thereof, a gel composition contacting a surface of the container, infused with a second fragrance, capable of evaporating from exposed surfaces of the gel composition, wherein the gel composition is adapted to contract dimensionally on evaporation of the second fragrance thereby to expose at least part of the surface of the container. As the gel contracts, it draws back and exposes initially-concealed surface area of the container and thus increases its available surface area from which fragrance can evaporate. That allows a greater rate of evaporation of the first fragrance, i.e. that infused into the container.

We refer to first and second fragrances; these fragrances can be identical, similar, or entirely different so as to create a blended fragrance. Where the two fragrances are the same or essentially the same, the invention allows the air freshener to continue emitting a fragrance to an effective degree for a longer period, since the gradual decline of the rate of evaporation from the gel is at least partially offset by evaporation from the newly-revealed surface area of the container as the gel contracts. Where the fragrances are different, over time the rate of evaporation of the second fragrance (from the gel) declines and is partially or fully offset by evaporation from the newly-revealed surface area of the container. Thus, the balance between the two fragrances changes over time thus also serving to address olfactory fatigue.

The gel composition is ideally surrounded by the container, such as by being located within a concave recess provided in the outer container, so that the gel composition initially contacts the interior faces of the container. A convenient form is for the container to be a cylinder surrounding the gel composition -ideally open at at least one end to ease construction of the apparatus by insertion of the gel into the interior. The container can comprise a plurality of apertures; where the container is cylindrical, these can extend radially through the cylindrical wall. The gel composition preferably extends partially or fully into the apertures, thus potentially increasing the change in exposed surface area as the gel contracts.

The outer container can be an ethylene-vinyl-acetate copolymer, and the fragrances can each be an oil-based fragrance.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the present invention will now be described by way of example, with reference to the accompanying figures in which; Figure 1 shows a perspective view of an air freshener according to the present invention; Figure 2 shows a side view of the air freshener of figure 1; Figures 3A and 36 show a top view and a sectional view of the air freshener of figure 1, in its fresh state, figure 35 being a section on A-A of figure 3A; Figures 4A and 4B show a top view and a sectional view of the air freshener of figure 1, after period of use, figure 4B being a section on B-B of figure 4A; and Figures 5A and 5B show a top view and a sectional view of the air freshener of figure 1, after an extended period of use, figure 5B being a section on C-C of figure 5A.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring to figures 1 and 2, the fragrance cartridge 10 according to the present invention comprises an outer shell 12 and a gel composition 14 contained within and retained by the outer shell 12. The cartridge can be used as a standalone air freshener, for example by placing it on a suitable surface in a room, or as a replaceable cartridge for use in a wall-mounted or other dispenser such as that illustrated in W02015/067505.

The cartridge 10 thus comprises a large moulded EVA block 12 impregnated with a fragrance complete with an integrated fragrance gel core 14 working uniquely together in a timed release phase to provide consistent fragrance performance whilst overcoming fragrance fatigue issues. The product contains no liquid, so there is no chance of leaking in transit or use. It is classed as non-hazardous for all shipping methods. The external shape of the cartridge is intended to be a universal fit, i.e. one that fits into all existing dispensers.

1-15 The fragrance impregnated into the EVA block 12 is (in this embodiment) different to that provided in the gel core. This allows us to produce a multi fragrance product, with effects and characteristics that change substantially over time. These fragrances are designed such that the focus of the fragrance (the powerful key chemicals and notes) are significantly different. These different mixtures (fragrances) can be chosen to be complementary, so that one fragrance ("a") in the gel and one fragrance ("b") in the EVA combine to produce a multitude of fragrances starting from primarily (a) or (b), developing over time to something in the middle being a balance of (a) & (b) and ending with either (b) and (a) [respectively]. Further, the fragrances for each part can be made of faster and slower evaporative chemicals (or groups of fragrance notes), such that each part (a) or (b) can have many sub-fragrances (al, a2, a3, and bl, b2, b3) that interact with each other to form other final fragrances in the air. This type of product would be difficult to become accustomed to, and fragrance fatigue would be avoided.

In other embodiments, the fragrances may be the same or essentially the same, which will result in a fragrance that does not change over time but which is maintained at a more consistent level and/or for longer, in the manner explained above. The fragrance gel compounds that we prefer are generally composed of: Item Amount (% amount by weight) Carrageenan 1.75 to 2.25 Preservative 0.15 Polyethylene Glycol (PEG-400) 15.0 to 20.0 Fragrance 10.0 to 25.0 Polysorbate 20 5.0 to 10.0 Water DI 68.1 to 42.6 0,10 Total 100.00 o Gels contain a carrier material, from which the perfume evaporates slowly and thus gives a pleasant smell to the atmosphere. The life time and the amount of perfume emitted per time unit are determined mainly by the amount of perfume in the air-freshener. In many known types of air-fresheners gelled water is used as carrier material. However, as perfumes are generally not or only hardly soluble in water, they should be dispersed therein as homogeneously as possible. Gelled organic solvents such as monohydric or polyhydric alcohols or glycol ethers can also be used as a carrier material, but water has the advantage of being cheap and toxicologically unsuspected.

Aqueous gels can be prepared in a wide range of known ways, using as a gelling agent compounds such as vegetable gums, especially carrageenan, agar-agar, alginates, pectin, guar gum, tragacanth, karaya gum and xanthan, or compounds such as gelatin, starch and cellulose derivatives. In some cases the gel strength can be increased by the addition of salts of bivalent or polyvalent metals like Ca, Mg, Al or Cr. Alternatively, synthetic polymers such as polyvinyl alcohol may be used as gelling agent. Such aqueous gels have the disadvantage that they may only contain a limited amount of perfume. In the literature a maximum perfume content of typically about 10% is mentioned, but in practice it appears that from a perfume content of more than about 6% strongly reduces the gel strength and/or causes syneresis whereby the perfume leaves the gel as a liquid.

Aqueous perfume gels are described for instance in published Japanese patent applications 54/110,990 (gelling agent: carragheenin and sodium stearate, perfume content up to 6%); 53/088,334 (gelling agent: bacterial polysaccharide, 1-10% of perfume); and 52/136,893 (gelling agent: carragheenin and polyvinyl alcohol, 2-4% of perfume), and in French patent application 2,293,976 (gelling agent: carboxymethyl cellulose/AI-salt, 5% of perfume). Dutch patent application 76,11041 also discloses the use of carboxymethyl cellulose and salts of trivalent metals as gelling agent in aqueous perfume gels. Although it is mentioned in the specification that these gels may contain up to 200/0 of perfume, the examples only illustrate a perfume content of 4%. Likewise, Dutch patent application 76,02254 discloses similar aqueous perfume gels which are said to be capable of containing up to 10% of perfume, whereas in the examples only gels containing up to 2.5°/0 of perfume are described. Dutch patent application 75,02596 describes aqueous gels based on mixtures of carragheenin and locust bean gum which according to the specification may also contain up to 10% of perfume, but from the examples it appears that no more than 3.3% of perfume 1-15 is used. Dutch patent application 76,12909 discloses gels based on amylose as gelling agent.

O The phrase "perfume" is used to mean a mixture of organic compounds such as aldehydes, ketones, nitriles, esters, carboxylic acids, alcohols and ethers which may also contain natural products like essential oils, resinoids, balsams and concretes. This mixture is meant to emit the desired smell. In many cases a perfume contains a mostly small amount of a solvent or diluent usual in perfumery, for instance because one or more of the components used in the composition are only available or manageable in solution.

Part of the water used for preparing the gel can optionally be replaced by water-miscible organic solvents like monohydric or polyhydric alcohols, for instance ethanol, isopropanol or ethylene glycol, as far as these solvents do not affect the good activity of the gelling agent used. This replacement is not generally recommended, but purely for economic reasons as organic solvents are more expensive than water.

The outer shell 12 part can be constructed of any suitable EVA material, and is infused with fragrance oil. EVA, or ethylene-vinyl acetate, also known as poly (ethylene-vinyl acetate) (PEVA), is an elastomeric polymer being a copolymer of ethylene and vinyl acetate. The weight percent vinyl acetate usually varies from 10 to 40%, with the remainder being ethylene. A fuller description of the material is provided at https://en.wikipedia.org/wiki/EthvIene-vinyl acetate which is hereby incorporated by reference and to which the skilled reader is referred for a fuller understanding of the present invention. This outer cartridge has a slow evaporation rate, and its release of fragrance oil is limited by the surface area of EVA exposed to the air.

The second component is the inner core, which is made from an organic gel infused with fragrance oil. The inner core has a faster evaporation rate, and as it does so it shrinks in size exposing further surface area of the outer cartridge EVA. The additional EVA surface exposed to the air then allows increased fragrance evaporation from the outer core, boosting the fragrance level and increasing the effective fragrance life of the product.

As shown in figure 3B, the EVA outer shell 12 is in a generally cylindrical form, with an internal closed bore 16 which receives and is substantially filled by the gel composition 14. Thus, a base or lower portion 18 of the cylinder is closed, whereas an upper or top portion 20 of the cylinder is open. This means that the gel composition 14 is adequately supported, but also exposed to the atmosphere via at least the upper portion 20 thereby allowing it to evaporate. The bore 16 tapers so that near to the closed end 18 it is narrower in width than near to the open end 20; this aids insertion of the gel composition 14.

A recess 22 is provided on the external part of the base portion 18, for receiving a locating peg provided in certain dispensers (figure 6). This then holds the cartridge 10 in a secure manner.

Towards the lower part of the outer shell 12, a plurality of recesses 24 are formed in the outer surface of the shell 12, closely-spaced so as to (in effect) create a plurality of fins 26 between them. These fins 26 serve to increase the surface area of the outer shell 12, and allow the initial surface area to be tailored as required in view of the fragrance loading that is planned for the cartridge 10.

Towards the upper part of the outer shell 12, around the internal bore 16 containing the gel composition 14, a plurality of radial through-holes 28 are provided in the outer shell 12. These extend from the exterior of the shell 12 through to the internal bore 16. In its initial state shown in figures 3A and 3B, the gel composition extends into and fills the through-holes 28 and its outer surface 30 is approximately level with the outer cylindrical extent of the shell 12. Thus, the faces of the internal bore 16 and of the through-holes 28 are covered by the gel composition 14, in the initial state of the cartridge 10 (i.e. when manufactured and/or immediately on removal from sealed packaging).

Figures 4A and 4B show the cartridge after 30 days use. The gel composition 14 has shrunk due to evaporation of the fragrance and other volatile components, and has withdrawn into the interior of the internal bore 16. This has created a gap 32 between the gel composition 14 and the sides of the through-holes 28, and a gap 34 between the gel composition 14 and the sides of the internal bore 16. These gaps expose additional surface area of the outer shell 12, allowing an increased rate of evaporation from the EVA surface.

Figures 5A and 5B show the cartridge after 60 days use. The gel composition 14 has shrunk still further and retreated to the interior of the internal bore 16, withdrawing entirely from the through-holes 28. This has widened the gaps 32, 34 allowing a greater airflow through those gaps, further promoting evaporation from the EVA surface.

CD15 Thus, as time passes the surface area of the EVA component increases as a result of the shrinkage of the gel composition, and the rate of evaporation of fragrance from it increases both due to the higher surface area and the greater air flow rate past it. In this way, the invention employs the otherwise undesirable shrinkage characteristics of the gel in order to solve the problem of olfactory fatigue.

It will of course be understood that many variations may be made to the above-described embodiment without departing from the scope of the present invention.

Claims

CLAIMS1. An air freshening apparatus, comprising; a container infused with a first fragrance capable of evaporating from the exposed surfaces thereof, a gel composition contacting a surface of the container, infused with a second fragrance, capable of evaporating from exposed surfaces of the gel composition, wherein the gel composition is adapted to contract dimensionally on evaporation of the second fragrance thereby to expose at least part of the surface of the container.
2. An air freshening apparatus according to claim 1, wherein the gel composition is surrounded by the container.
3. An air freshening apparatus according to claim 2 in which the gel composition is located within a concave recess provided in the container.
4. An air freshening apparatus according to claim 2 or claim 3 in which the container is in the form of a cylinder surrounding the gel composition.
5. An air freshening apparatus according to claim 4 in which the cylinder is open at at least one end.
6. An air freshening apparatus according to any one of claims 2 to Sin which the container comprises a plurality of apertures.
7. An air freshening apparatus according to claim 4 in which the container comprises a plurality of apertures extending radially through the cylindrical wall.
8. An air freshening apparatus according to claim 7 in which the gel composition extends at least partially into the apertures.
9. An air freshening apparatus according to any one of claims 2 to 8 in which the gel composition initially contacts the interior faces of the container.
10. An air freshening apparatus according to any one of the preceding claims, in which the container is composed of an ethylene-vinyl-acetate copolymer.
11. An air freshening apparatus according to any one of the preceding claims in which the first fragrance is an oil-based fragrance.
12. An air freshening apparatus according to any one of the preceding claims in which the second fragrance is an oil-based fragrance.
13. An air freshening apparatus according to any one of the preceding claims in which the first fragrance and the second fragrance differ from each other.