GB2271716A - Propellant-free deodorant composition - Google Patents

Abstract

A propellant-free deodorant composition suitable for topical application to the human skin, comprises an effective amount of a known deodorant compound, which may be chosen from salts or oxides of zinc or magnesium, and from 2 - 6% by weight of the composition of a cellulosic polymer having a water absorbing capacity of at least 1.

Description

Deodorant Comnosition This invention relates to deodorant compositions suitable for application to the human skin, in particular liquid and solid compositions. Such compositions may be suitable for use from a roll on dispenser, or from a pump action dispenser, or as a stick form.

The deodorant and antiperspirant market is dominated with products which are based on aluminium or zirconium salts, which are intended to prevent, or at least to control perspiration at the skin surface, particularly at the underarm, whilst at the same time providing a perceived degree of deodorancy.

It is also known, for example from EP471392 (Unilever NV), that certain classes of water absorbing materials can be incorporated into such deodorant or antiperspirant products.

This publication describes propellant-free compositions which comprise an effective amount of a known deodorant, such as salt or oxide of zinc or magnesium, a volatile silicone, and a cellulosic polymer having a water absorbing capacity of at least 1.

A problem with such water-absorbing polymer compositions, in particular those which are in liquid or stick form, is that they are at times not perceived to offer a good degree of perspiration control to the user. Additionally, with some users there is perceived an unpleasant wet, slimy sensation in the axilla.

It is an object of this invention to provide a deodorant composition which does not suffer from this disadvantage, and in particular provides for the user an improved perception of wetness control.

Thus, according to the invention, there is provided a propellant-free deodorant composition suitable for topical application to the human skin, comprising an effective amount of a known deodorant compound, which may be chosen from salts or oxides of zinc or magnesium, and from 2-6 % by weight of the composition of a cellulosic polymer having a water absorbing capacity of at least 1. Preferably, the cellulosic polymer has an average particle size such that at least 90% by weight of the polymer has a particle size of less than 45 microns.

According to a further aspect of the invention, there is provided a method of controlling perspitation on the human skin, for example at the axilla, comprising applying to the skin an effective amount of a composition comprising a deodorant compound, and a cellulosic polymer having a water absorbing capacity of at least 1, the amount of solids present in the composition being limited such that gel blinding of the polymer does not occur on the skin.

As mentioned above, a perceived problem with the use of known deodorant compositions which contain water absorbing polymers is that they sometimes provide an inadequate degree of perspiration control. As such, these compositions may provide the user with a wet slimy feeling in the axilla, and may be unpleasant to use. Such a problem has been found to be more pronounced with propellant-free compositions ie. primarily those which are in lotion or stick form.

Through further studies of such compositions, we have found that a possible reason this lies in the behaviour of the polymer once it has been deposited on the skin by the different product forms.

Of the different polymers which are used in such compositions, such as Akucell SW3009 (cross-linked sodium carboxymethyl cellulose, ex. Akzo), these polymers are capable of absorbing sufficient fluid in use such that they expand to 10-11 times their original size.

Without wishing to be bound by theory, it is thought that if such gel polymer particles are deposited on the skin without sufficient room to swell on hydration, then they cannot absorb moisture without impinging severely on each other.

Wetting then becomes variable across the gel layer, and "gel blindingl occurs. The result is that non-optimum conditions for water absorption prevail, and the gel can no longer absorb water and remain essentially as a single layer. Gel blinding hence reduces both the water uptake of the gel, and the rate at which water can evaporate from the gel (since evaporation is likewise hindered). Consequently, the user perceives a reduced effectiveness of the composition.

The condition for gel blinding not to occur is that the composition is deposited on the skin in such a way that there is sufficient room on the skin for the cellulosic polymer particles to expand on water uptake, without impinging on each other (and also on other solid components of the composition).

It is thought that, with the levels and particle sizes of cellulosic polymer typically found in propellant-free compositions (in particular lotion forms), combined with the particle size of the other solid components of the composition, that in typical consumer applications of such products the effect of gel blinding often occurs. Typical application rates may easily lead to a deposition by the user of a bed of particles in the axilla which is 2-3 particles thick. As a result, the consumer perceives reduced effectiveness of the composition.

A surprising solution to perceived problems with using such propellant-free compositions therefore lies in actually reducing the amount of cellulosic polymer to be found in such compositions. It is noted that in EP471392 mentioned above, the application only actually exemplifies compositions which comprise 10% by weight of a cellulosic polymer having a water absorbing capacity of greater than 1.

We have found that propellant free compositions which comprise a deodorant active, and from 2-6% by weight of the composition of a cellulosic polymer having a water absorbing capacity of greater than 1, the polymer having a particle size such that 90% by weight of the polymer in the composition has a particle size of less than 90 microns, are particularly effective in overcoming the problems of previous compositions.

In a preferred embodiment of the invention, compositions may additionally comprise a water-soluble deodorant active. In such deodorant compositions which comprise water absorbing polymers, after the user has undergone a major sweat generating event there will result an at least partially swollen polymer gel on the skin, which may typically exist in this swollen state for at least one hour. This swollen gel is a good environment in which bacteria may be cultured, in particular bacteria which may contribute to the odourgenerating process. In a preferred embodiment, there is therefore provide a composition which provides deodorant activity both on the human skin and also in the applied polymer gel.A preferred composition according to the invention additionally comprises a water soluble deodorant active which is capable of permeating the swollen gel, and preventing the odour-generating process occurring therein.

Additionally, a benefit with such compositions is that there is the potential to reduce the amount of conventional deodorant actives such as (insoluble) zinc carbonate required in the gel, and hence further reduce the possible incidence of gel blinding.

The deodorant active which is present in the composition may be any conventional deodorant active, but is preferably a salt or oxide of zinc or magnesium which is insoluble or only sparingly soluble in water. Examples of suitable salts include zinc oxide, zinc carbonate, zinc citrate, zinc laurate, zinc oleate, zinc orthophosphate, zinc silicate, zinc stearate, zinc tartrate, magnesium oxide, magnesium carbonate, magnesium fluoride, magnesium hydroxide, magnesium laurate, magnesium myristate, magnesium oleate, magnesium palmitate, magnesium stearate, magnesium orthophosphate, magnesium pyrophosphate, and magnesium silicate.

The amount of deodorant active in the composition according to the invention is typically from 0.5-20%, preferably 1-15% by weight of the composition.

The cellulosic polymer in the composition according to the invention is one which has a water absorbing capacity of at least 1. By "water absorbing capacity" is meant a polymer which is capable of absorbing an amount of water at least equal to its own weight. The polymer also has a particle size distribution such that at least 90% of the particles have a particle size of 45 microns or less.

Preferably, the cellulosic polymer will have a water absorbing capacity of at least 5, more preferably at least 10 or higher.

Particularly preferred examples of polymer in compositions according to the invention are Akucell SW3009, a crosslinked sodium carboxymethyl cellulose, ex. Akzo, and Blanose A250, a cross-linked sodium carboxymethyl cellulose, ex.Hercules.

The amount of cellulosic polymer in the composition according to the invention is from 1.5-6%, more preferably from 2.5-5% by weight of the total composition.

Compositions according to the invention may also comprise other components typically found in such compositions, including; - linear or cyclic volatile silicones, including polydimethyl siloxanes such as Dow Corning 344 Fluid and Dow corning 345 Fluid, and volatile hexamethyldisiloxane such as Dow Corning 200 Fluid, - non-volatile silicones, including polydimethylsiloxane such as Dow Corning Fluids, - thickeners, such as clays, for example Bentone 38, and silicas, for example Aerosil 200, - skin feel improvers, such as talc and finely divided polyethylene, for example Acumist B18, - cosmetically acceptable vehicles, such as anhydrous ethanol and other emollients, - gelling agents, such as stearyl alcohol or waxes, such as castor wax, - perfumes, - preservatives, and - other cosmetically acceptable adjuncts conventionally employed in stick, roll-on and propellant-free spray deodorant products.

The ingredients in the composition other than the deodorant active and the cellulosic polymer which can be optionally present in the composition conveniently form the balance of the composition, and accordingly can form up to 97.5% by weight of the composition.

The composition according to the invention can take the form of liquid or solid products, each of which is suited to or adapted for topical application to the human skin. One convenient form of the product is as a solid stick, usually contained in a suitable holder to enable it to be applied to the area of the skin, particularly the underarm, where it is required.

A preferred form of the composition of the invention is a lotion suitable for dispensing from a roll-on dispenser fitted with a ball valve, to enable the product to be rolled onto the skin in a conventional fashion. A further example of the composition of the invention is as a liquid composition suitable for dispensing with a finger operated pump spray or hand operated squeeze spray, to deliver to the skin a finely divided liquid spray, without the use of propellant gases.

Examples The following examples further illustrate the invention; Examnles 1-4 - Lotions 8 (W/W) Component 1 2 3 4 Akucell (1) 5.0 5.0 2.5 2.5 Bentone 38 1.0 2.5 1.0 2.5 Acumist B18 (2) 7.0 - 7.0 Zinc Carbonate 8.0 2.0 8.0 2.0 Volatile silicone 78.5 18.0 81.0 20.5 Anhydrous ethanol 0.5 72.5 0.5 72.5 (1) ex. Akzo (2) finely divided polyethylene powder - particle size 18 microns The above formulations all have satisfactory properties.

Claims (3)

Claims

1. A propellant-free deodorant composition suitable for topical application to the human skin, comprising an effective amount of a known deodorant compound, which may be chosen from salts or oxides of zinc or magnesium, and from 2-6 % by weight of the composition of a cellulosic polymer having a water absorbing capacity of at least 1.

2. A deodorant composition according to claim 1, wherein the cellulosic polymer has an average particle size such that at least 90% by weight of the polymer in the composition has a particle size of less than 45 microns.

3. A method of controlling perspiration on the human skin, for example at the axilla, comprising applying to the skin an effective amount of a composition comprising a deodorant compound, and a cellulosic polymer having a water absorbing capacity of at least 1, the amount of solids present in the composition being limited such that on hydration gel blinding of the polymer does not occur on the skin.