GB2347350A - Indicating useful life of volatile material. - Google Patents

Abstract

A method for indicating a prolonged loss of a volatile active over a period of time, the method comprising locating, adjacent to the active, a holographic element in which a holographic image is or may be displayed whereby the hologram changes in response to prolonged loss of the active.

Description

IMPROVEMENTS IN OR RELATING TO ORGANIC COMPOSITIONS This invention relates to end of life indicators, for instance, in products which contain a compound or composition which is evaporates off during the use of the product.

With many products, it is difficult to know when the active volatile agent has been exhausted and whether either the active agent or the whole of the product needs replacing.

An example of such a product an air freshen-ng product which includes a housing containing an air freshening agent. During the active lifetime of the product, the air freshening agent slowly vaporises and escapes from the housing into the atmosphere, hereby performing its air freshening function. However, it is very difficult to ascertain when the air freshening agent is exhausted particularly since, with many products which includes a plastic housing, the air freshening smell tends to persist after the volatile active agent has vaporised off because of absorption of the air freshening agent into the plastics housing.

In practice, such products (as air freshene-s and similar products where gradual depletion of the active agent takes place) are often replaced before the active agent has been exhausted or, perhaps equally as often, a considerable time after the active agent has been exhausted.

One proposed solution to this problem is to provide products with an end of life indicator label which incorporates elements which can slowly undergo a chemical reaction over the specified period of time to end of life, at the end of which period of time a colour change takes place. Such an arrangement can be designed so that the colour change will take place after, say a period of two weeks which is calculated as the average period over which exhaustion of the active agent in a product takes place. Such a solution to the problem provides, in effect, a cheap chemical clock.

However, the time to exhaustion of many products is not predicable and can be variable. Many factors determine the time to exhaustion e. g. temperature, humidity and location of the air freshener. In the case of an air freshening product, for example, exhaustion may take place within a period of three weeks during the summer while, during the winter, the product may last perhaps twice as long. The chemical end of life indicator label will, however, change colour over a period which is much less variable and, therefore, if the label is designed to change colour after. a period of three weeks, then, at least during the winter, the product will only part-ally be exhausted at that time.

According to one aspect of the present invention, there is provided a method for indicat ng a prolonged loss of a volatile active over a period of time, the method comprising locating, adjacent to the active, a holographic element in which a holographic image is or may be displayed whereby the hologram changes in response to prolonged loss of the active.

Preferably the prolonged loss of active measured is the period in which exhaustion of the active substantially occurs.

In this specification, the volatile active may be either a volatile single compound or a volatile composition.

According to a second aspect of the invention, there is provided a device incorporating a volatile active which evaporates off during use of the device, the device containing i) a volatile active or means for receiving a volatile active and ii) a holographic element, which is located proximal to the active, in which a holographic image may be displayed, whereby the holographic image changes in response to evaporation (preferably to substantially full exhaustion) of the said active.

Preferably the holographic image either changes colour or appears or disappears on substantial exhaustion of the volatile compound or composition.

Examples of devices within the scope of the present invention are products from which aroma or perfume vaporise off (ie air fresheners) and products from which insecticide vaporises off, (such as vaporisable insecticidal killers or repellents).

A preferred form of a device according to the invention is an air freshening device.

Preferably such an air freshening device comprises i) a housing accommodating a gel containing an air freshening agent; and ii) a holographic element, which is located proximal to the active, in which a holographic image may be displayed, whereby the holographic image changes in response to evaporation (preferably to substantially full exhaustion) of the said air freshening agent.

The gel is preferably a hydrogel or an organic-based gel, in which an air freshening agent is dispersed.

The housing is perforated to allow the air freshening agent to escape from the gel out of the housing and into the atmosphere.

During this process the gel, which contains vaporisable active will lose active so that, when the gel is exhausted, the gel is of a reduced size.

Preferably the vaporisable active contains volatile perfume or a water-based vaporisable perfume system.

A holographic element may be mounted in the wall of the housing of the air freshening product.

The holographic image should preferably be viewable from outside the housing.

Preferably the holographic element is capable of i) absorbing the vaporisable active from its surroundings and ii) of giving up the active to its surroundings.

As a result, the optical characteristics of the holographic element will change so that, to the observer, the holographic image will have a different appearance.

The holographic element may be positioned so that the support is in direct contact with the gel containing the air freshening agent. Alternatively, the support of the holographic element may be spaced from the ge-.

WO/95, 26 99 describes in detail the various features of type of holographic elements which can be used in the present invention, the contents of which are incorporated herein by reference.

In a preferred hydrogel air freshener, the gel is initially largely composed of water, and the holographic element will either be in contact with the hydrogel or, where there is a space between the gel and the holographic element, the humidity within the housing will be high and the holographic element will take up : even to saturation in some cases) water.

When the hydrogel has become exhausted, it will have dried oui and, accordingly, water will have evaporated from the holographic element. As a result, the holographic element will change physical properties and this will cause the holographic image to change so that light reflected therefrom will be of a different wavelength.

The hologram may be such that the change in the physical property of the holographic element will cause the holographic images to change the colour, for example from green, indicated that the product is not exhausted, to red indicating that the product has become exhausted. Alternatively the hologram may change from a colour to a non-colour or vice versa.

The holographic image may include or be a 3-dimensional design.

In the case of an air freshener or similar device, the holographic element may be located in the wall of the housing of the product. The product, when sold, may include a cover element which is peeled off when the product is to be used.

Alternatively the volatile active may be present in a non-aqueous gel that release perfuses, or a reservoir of liquid or an agent which is impregnated into a porous substrate eg fibrous mats, pclymeric porous material or porous porcelain.

The chemical entity inducinc a change in the holographic element may be, as indicated, water or some other chemical such as an organ-c, volatile chemical.

The invention will now be illustrated by the following Example and with reference t the accompanying drawings, in which : Figure 1 is a section through an air freshener product in accordance with the present invention; Figure 2 is a rear view of the produit of Figure 1 ; Figure 3 is a front view or the product of Figure 1, and Figure 4 shows in greater detail a section of the front of the product of Figure 1 tocether with a tool used in the assembly thereof.

Example Referring to the accompanying an air freshening product 1 includes a housing formed of two components 3,5, made of plastics rr. ateriai, that have been pressed together. Component fcrms a main body of the housing including the rear and side parts thereof. The rear of component 3 is provided with a large number of perforations or noves'. As seen in Figures 2 and 3 the side wal@ 9 of the housing, forming part of component 3, is generally circular although provided with a fla@tened angled lower surface 11 upon which the product r. ay be stood. The slope of surface 11 is 15"from a plane au right angles to the front and rear wa-ls of the product.

Accordingly, when the prcduct is rested on surface 11 the front wall 5 will be ~il~ed upwardly, thereby providing a greater angle of view to an observer.

Front wall components 5 has, extending rearwardly therefrom into the body of the hous-ng, three gel support pins 13 (two only shown in Figure 1). These support pins 13 carry a solid gel (not shown) impregnated with air freshening agent.

Located centrally in component 5 is a window 15 of circular shape. Window 15 is defined by edge 17 whose diameter decreased from the front edge of the component 5 to a position close to the rear edge thereof. Extending rearwardly from sloping edge 17 is a short length edge 19 of constant diameter. Behind edge 19 extending from the rear cf component 5 into the space within housing 1 is a circular rim of flange 21 having a diameter greater than that of a window edge 19.

Located against the rear of component 5 and within rim 21 is a holographic disc 23 comprising a hologram mounted on a support, this disc being substantially as described in WO 95/26499. In particular, it includes a gel like material capable o expa-dirg or shrinking slightly in response to the arourt cf-ater located within the material.

Figure 4 of the accompanyinc d- w-ng illustrates the location of the holographic d-sc at the rear of the window 15. This drawing also illustrates a tool, known as a staking tool, used for securing the holographic disc in the position shown in Figure 4.

The end of the tool is heated to a temperature of about 180 C and is applied to the rim 21 causing it to deform and permanently hold the holographic disc in position. An air freshening gel composition suitable for use in the above described product, was made in 1. 5kg batches each comprising the following : g % Hard Water (A) 980.0 65. 30 Colour Pigment 5.1 0. 34 Carrageenan Gel 37.5 2.50 (eg Danagel 6294 (DKL)) Surfactant 3.0 0.20 (eg Crillet 4 Super) Hard Water (B) 325.0 21.56 Preservative 1.5 0.10 (eg Parmetol DF 35) Fragrance 150.0 10.0 To make the gel composition, water (A) and the pigment was added to a 2 litre round bottored flask.

A stirrer located within the flask was adjusted to the correct height and the contents of the flash stirred at 450 rpm.

When the temperature of the contents of-ne flask reached 50 C, the carrageenan gel was slowly added.

Heating was continued until a temperature cf 90 C was reached. If necessary, the speed of a stirrer was adjusted to ensure liquid around the edge cf vessel was not stationary. The temperature was held at 90 C for 30 minutes or until any lumps had disperse.

The heater was turned off and the surfactant was added. The remaining water (B) was then slowly added followed by the preservative. The resultant mixture was allowed to cool to 70 C. The fragrance was then slowly added. A temperature was held at 65 C for 10 minutes to ensure a homogenous batch.

The resultant product was filled via the examination holes described in figures 1 to 4 using a 20 ml syringe. The temperature of the fill was monitored with a temperature probe. A self adhesive label was applied to cover the emanating holes.

The holographic image took 24 hours to become fully developed and display a stable colour.

To commence the air freshener emanation, the self adhesive label was removed.

After 42 days in a controlled atmosphere at 22 C and 50% humidity, the holographic image had become dark red with little brilliance and substantially reduced visibility. The initial colour was a highly visible brilliant gold/green which changed to a dull red with little brilliance.

Claims (6)

1. Claims 1. A method for indicating a prolonged loss of a volatile active over a period of time, the method comprising locating, adjacent to the active, a holographic element in which a holographic image is or may be displayed whereby the hologram changes in response to prolonged loss of the active.
2. 2. A method according to Claim 1 in which the holographic image changes colour or appears or disappears on substantial exhaustion of the volatile compound or composition.
3. 3. A method according to Claim 1 or Claim 2 in which the volatile compound or composition is an aroma, a perfume, a vaporisable insecticidal product, a vaporisable insect repellent or killer.
4. 4. A device incorporating a volatile active (eg compound or composition) which evaporates off during use of the device, the device containing i) a volatile active or means for receiving a volatile active and ii) a holographic element, which is located proximal to the active, in which a holographic image may be displayed, whereby the holographic image changes in response to evaporation (preferably to exhaustion) of the said active.
5. 5. A device according to Claim 4 which is a device releasing perfume, aroma or volatile insect repelling or killer products.
6. 6. An end of life indicating method substantially as herein described with reference to the Example.

   6. A device substantially as herein described with reference to the Example.

   7. An end of life indicating method substantially as herein described with reference to the Example.

   Amendments to the claims have been filed as follows

   1. A method for indicating a prolonged loss of a volatile active agent over a period of time, the method comprising locating, adjacent to the volatile active agent, a holographic element which displays or is capable of displaying a holographic image, whereby the holographic image changes colour or appears or disappears on substantial exhaustion of the volatile active agent.

   2. A method according to Claim 1 in which the volatile active agent is an aroma, a perfume, a vaporisable insecticidal product, or a vaporisable insect repellent or killer.

   3. A device incorporating a volatile active agent which evaporates during use of the device, the device containing i) a volatile active agent or means for receiving a volatile active agent and ii) a holographic element located proximally to the active agent, in which element a holographic image is capable of being displayed, whereby, in use, the holographic image changes in response to evaporation of the volatile active agent.

   4. A device according to Claim 3 which is a device releasing perfume, aroma or volatile insect repelling or killer products.

   5. A device substantially as herein described with reference to the Example.