The present invention relates to air care products and, in particular, to products which are capable of diffusing perfume or deodorizing components into the surrounding air.
The use of various devices for the diffusion of volatile compounds, for example perfumes, deodorizing compositions, insect repellents, and the like, into the atmosphere has become increasingly popular in recent years. For example, air-freshening devices or deodorizers are currently used in practically all households to mask bad odors, or to impart fragrances to the ambient air. Various different types of devices are known for the diffusion of volatile compounds into the surroundings. For example, devices of the spray type, such as aerosol sprays, may be used to dispense a liquid composition into the ambient air. Other devices comprise housings enclosing the active ingredients in liquid form. Typically, the diffusion of the active ingredients takes place through membranes permeable to the vapors of said ingredient, or through a wick which is placed in a reservoir containing the ingredients.
Solid state devices are also known which comprise solid materials or carriers impregnated with an active ingredient. Such devices may be formed of various materials which are capable of absorbing the ingredient and subsequently releasing it in a more or less controlled manner. Examples of such known materials include gels, such as agar-agar or sodium stearate gels, synthetic polymer resins, or blocks of mineral material, e.g., plaster or silica.
Solid state devices have the advantage that they are easy to handle and can be easily shaped. Typically, the solid state devices are enclosed within a housing with one or more grills which communicate with the surrounding air.
The main disadvantage with solid state devices is that the release of active ingredients from the blocks is not constant with time and drops dramatically over the lifetime of the device. Furthermore, such devices are inefficient, in that the device may cease to diffuse the active ingredient into the surrounding atmosphere when the outside of the block is spent, even though considerable amounts of the active ingredient may still reside within the core of the block. The residual active ingredient, such as perfume, is thus totally lost.
International patent application Publication WO 96/05870 discloses a device for perfuming, deodorizing or sanitizing air or enclosed spaces which comprises an anhydrous gel element. Such a device is capable of diffusing volatile substances at a relatively constant rate throughout the entire lifetime of the device and, furthermore, is capable of releasing substantially all of the volatile substance into the air or enclosed space within its effective lifetime.
The devices of WO 96/05870, although practically very useful, are unattractive since they are in the form of substantially colorless gels. However, because of the manner in which the gels are formed, it is difficult to incorporate dyes or colorants into the gels. Many dyes will not disperse within the system and result in unattractive, non-homogenous products, in which the dye is not uniformly dispersed therethrough. Neither the colorless gels of WO 96/05870 nor the non-homogenous colored gels would be attractive to the purchaser of such devices, which generally will be on display in the room or space which they are intended to perfume or deodorize.