GB2443517A - Gel-based liquid disseminator - Google Patents

Abstract

An apparatus adapted to disseminate a volatile liquid, such as a fragrance, into an atmosphere, comprising a gel loaded with the liquid, and from which liquid vapour disseminates into the atmosphere from an exposed surface of the gel, the exposed surface being covered with a vapour-impermeable film that is adapted to be manually removable in sections. The air freshener is a shallow tray 1 with a lip filled with a gel, which is loaded with a fragrance. The gel is covered by an aluminium barrier film 2. This film is divided by perforations 3 into tearable strips, which can be removed by pulling on a pull tab 4 at the end of each strip. The apparatus is simple to construct, reliable and efficient in operation and can give a good end-of life indication.

Description

GEL-BASED LIQUID DISSEMINATOR

This invention relates to gel-based apparatus for disseminating volatile liquids into an atmosphere, such as a room or the interior of a motor vehicle.

Gel-based apparatus for disseminating a volatile liquid such as a fragrance into an atmosphere in the form of a vapour are well known and air fresheners based on this principle are widely commercially available. The apparatus comprise an organic or inorganic gel in which the liquid is dissolved, and it evaporates from an exposed surface.

Gels are now capable of absorbing a high liquid content (up to 80% of the weight of gel plus liquid).

One of the major problems with gels is the fact that the emission of liquid is relatively high, often excessively high, when the gel is newly put into operation and low as the gel approaches the end of its life. This is a particular problem when it is desired, for example, to use a gel-based air freshener in a motor vehicle, in which, on a hot day, the temperature S...

* can be very high. In such conditions, the entire contents of a gel-based air freshener can be : **, exhausted very quickly and the fragrance inside the vehicle can be overwhelming. *sas S. * * S S

* 20 There have been suggested a number of ways of overcoming this problem. Many have involved some sort of automated shuttering or gradual exposure of the gel to the atmosphere. These are effective, but they are also complex (and therefore inherently less reliable) and expensive. This makes them undesirable for many applications.

It has now been found that it is possible to provide a cheap, efficient gel-based volatile liquid dissemination apparatus that overcomes these deficiencies in the art and allows gel-based apparatus to be used in situations where it was not previously possible without adverse consumer reaction. There is therefore provided an apparatus adapted to disseminate a volatile liquid into an atmosphere, comprising a gel loaded with the liquid, and from which liquid vapour disseminates into the atmosphere from an exposed surface of the gel, the exposed surface being covered with a vapour-impermeable film that is adapted to be manually removable in sections.

There is further provided a method of maintaining a desirable level of a volatile liquid in an atmosphere, comprising the provision of the liquid dissolved in a gel, the surface of which gel provides an evaporating surface for liquid vapour and which surface is covered with a vapour-impermeable film, and removing the film in sections at an atmosphere liquid level.maintaining rate.

The gel for use in this invention may be any suitable gel known to the art to be suitable for such a purpose. Typical examples of such are those that can contain a fragrance load in excess of 50% (w/w), such as fumed silica gels (CarbosilTM), or ftinctionalised polymers that are cross-linked in situ, such as the cross-linked polymer system comprising functionalised liquid polymer and a copolymer of ethylene and maleic anhydride as : ** described in US Patent 5,780,527, or a gel such as described in US Patent 5,643,866 in which the fragrance is gelled with one or more glycols and dibenzylidene sorbitol acetal.

* 15 Ester compounds of oil-soluble, straight-chain or branched saturated or unsaturated fatty * acid having 14 to 18 carbon atoms, for example, dextrin stearate, dextrin palmitate, dextrin oleate, dextrin isopalmitate, dextrin isostearate and the like are also suitable. * * * S ***.

The gels may contain ingredients known to those skilled in the art such as dyes, preferably oil-soluble dyes, denatonium benzoate, IJV abosrbers, sequestrants, anti-oxidants and the like.

The liquid may be selected from any suitable liquid whose presence in an atmosphere may be desired. The most usual case is fragrance for air freshener use, but any other liquid may be used, for examples, disinfectants, fungicides, insecticides, medicinal compounds and the like.

Provided that the gel has a surface that may be exposed to the atmosphere to permit dissemination of volatile liquid, the form of the apparatus is not critical and it may be made in any shape, size or form desired, either practical or aesthetic.

The surface of the gel from which liquid is to be disseminated is covered with a film, which may be removed in sections. The film must be impermeable to the vapour of the liquid to an acceptable degree. The film may be a metal, typically aluminium foil.

Alternatively, it may be polymeric. There are many polymeric materials that are impermeable to particular vapours, and a suitable material may be chosen for any desired liquid. Non-limiting examples of such materials include ethylene vinyl alcohol copolymer, polyvinyl alcohol, polyethylene terephthalate, gI ycol-modifi ed polyethylene terephthalate, acid-modi fled polyethylene terephthalate, polybutylene terephthalate, vinyl idene chloride copolymer, polyvinyl chloride polymer, vinyl chloride copolymer, polyamide polymer and polyamide copolymer. Such materials may be used by themselves, or they may be used in combination with others, either as blends or as laminates. Laminated polymeric films are now widely available.

*::::* The actual arrangement of the film on the gel surface is not critical, provided that it can be easily removed in Sections, thus exposing only part of the gel surface at a time. For *.S.

*: 15 example, the film may be applied to the surface as a series of individual contiguous or *.s.

* * overlapping strips, each provided with a suitable means for easy removal, such as a pull- : *, tag. Alternatively, the film may be provided as a continuous sheet suitably perforated such **S.

*:*. that one part can be removed at a time, leaving the rest intact. The removable portions defined by the perforations may also incorporate means of individual removal, such as pull-tags. Provided that a suitable area of film is removed to maintain the atmospheric liquid level, the form of the area is not critical and any practical or decorative arrangement may be used, for example a linear series of strips or a series of radial strips emanating from a centre.

The film may comprise printed matter, such as graphics and other information such as use instructions.

In a particular embodiment, the film or films is/are transparent, so that the colour of the gel can be seen.

The apparatus according to this invention are easily manufactured using known materials and methods. They are effective and reliable in use.

The apparatus is now further described with reference to the drawings, which depicts particular embodiments, and which is not intended to be in any way limiting on the scope of the invention.

Figure 1 depicts an air freshener at three different stages of its utilisation.

Figure 2 depicts a further embodiment of the invention, again showing it at three different stages of utilisation.

In Figure 1, the air freshener is a shallow tray 1 with a lip and filled with a gel, which is loaded with fragrance. The gel used in this particular case is a clear, crosslii*ed, polymeric gel composition that is the reaction product of a microemulsion containing 18.15 wt. %, of : an anhydride functionalized polymer, 0.10 wt %, of a cross-linking agent, 5.0 wt % *.S* SteolTM surfactant, and 76.75 wt. % of an aldehydic fragrance. The gel composition is s... 15 prepared by combining the anhydride-fiznctjonalized polymer, the cross-linking agent, the S...

*: surfactant, the water, and the hydrophobic liquid-form a microemulsion and then gelling : the microemulsion. The skilled person will appreciate that many other gels can also be used.

S S Si * *.

The gel is covered by an aluminium barrier film 2 which has pressure glue on that part corresponding to the lip, thus holding it in place. This film is divided by perforations 3 into tearable strips, which can be removed by pulling on a pull tab 4 at the end of each strip.

Figure la shows the air freshener prior to use.

To commence using, one of the pull tabs 4 is pulled and the corresponding strip of film removed, to expose the gel surface 5 underneath to the atmosphere, as shown in Figure lb. In Figure ic, all strips have been removed and the air freshener is able to emit fragrance until exhausted.

Figure 2 shows an air freshener which is a shallow tray 6 filled with the same fragrance- loaded gel, as described in relation to Figure 1. In this case, there are two horizontally-opposed gel segments, covered by aluminium barrier films 7, 8. These are held in place by pressure glue to fix them to the face of the tray.

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Figure 2a shows the air freshener prior to use.

To commence using, one of the film pieces 7 is removed to expose the gel surface 9 underneath to the atmosphere, as shown in Figure 2b.

In Figure 2c, both segments of the barrier film have been removed and the air freshener is able to emit fragrance from both gel segments 9,10 until exhausted. *S*.

The skilled person will realise that there are many possible variants of this invention that are within the ordinary skill of the art and that fall within the scope of the invention. **S.

: * An example showing the effectiveness of the invention. *SS,

A polymerised gel in-situ fragrance gel was made to the following formula: ingredients Suppliers % by Weight Phase I 1. LithenelM N4-9000-MA 10 Synthomer 16.50 2. Fragrance Givaudan 50.00 Phase II 3. Oil soluble dyes 0.48 Phase III 4. Fragrance Givaudan 26.27 6. SteolTM CS-460 Stepan 5.00 7 JeffamineTM 1-403 Hunstman L1.

100.00 Procedure: A-In a suitable container begin mixing Phase I. Mix well until uniform.

B-In another container mix Phase III until uniform.

C-Add Phase II to Phase I and mix until uniform.

D-Add Phase III to Phase I and II. Mix well for 5 minutes or until uniform.

C-Pour into container I 25% Exposed 35.5 % Exposed 100% ExPosedi : g/day lost g/day lost g/day lost loss 0.20 0.28 0.39 *.S. * * **S* a

* Thus exposing only part of the gel surface is able to reduce the amount of the volatile : .. liquid lost to the atmosphere, hence providing an effective means of reducing the intensity *iii ofthe fragrance at the start of use.

Claims (2)

1. We claim: I. An apparatus adapted to disseminate a volatile liquid into

   an atmosphere, comprising a gel loaded with the liquid, and from which liquid vapour disseminates into t1 e atmosphere from an exposed surface of the gel, the exposed surface being covered with a vapour-impermeable film that is adapted to be manually removable in sections.
2. 2. A method of maintaining a desirable level of a volatile liquid in an atmosphere, comprising the provision of the liquid dissolved in a gel, the surface of which gel provides an evaporating surface for liquid vapour and which surface is covered with a vapour-impermeable film, and removing the film in sections at an atmosphere liquid level.maintaining rate. * * **. **** * S *S* *

   S'S... * . * S. * * S S... S. 5 S S a * ..