Field of the Invention The present invention is in the field of dry shampoo compositions, in particular relates to a dry shampoo composition with improved conditioning benefits.

Background of the Invention Dry shampoos have existed for many years, either in powder form or in aerosol form.

Dry shampoos are compositions for cleansing the hair without washing with water. The product provides clean feel and look on days when perhaps there is no opportunity, either through lack of time for conventional washing and drying or lack of available water, to wash the hair.

Dry shampoos work by absorbing the serum using sebum absorbers such as starches, and polymeric particles. Starches are one of the most commonly used sebum absorbers.

For providing a conditioning benefit through dry shampoo compositions, it is known to use conditioning agents such as conditioning oils, whereby it is expected that an increase in conditioning agents, increases the conditioning effects. Despite developments in the art, there remains a need for improved dry shampoos. In particular, there is a need for dry shampoo compositions to provide improved sebum removal, i.e. cleansing of the hair and also to provide increased conditioning benefits without losing the sensorial benefits. It is therefore an object of the present invention to provide a dry shampoo composition with improved conditioning benefits. It is another object of the present invention to provide a dry shampoo composition with improved conditioning benefits while maintaining the sensory benefits.

It is yet another object of the present invention to provide a dry shampoo composition with improved friction reduction.

Surprisingly, it has been found that for dry shampoo cleansing systems comprising a high concentration of starch, a conditioning benefit can be provided with low concentrations of isopropyl myristate.

Summary of the Invention

Accordingly, in a first aspect, the present invention provides a dry shampoo composition comprising a base and a propellant; wherein the base comprises starch and isopropyl myristate, wherein the starch is present in an amount of 5 to 15% and isopropyl myristate in an amount of 0.30 to 1% by weight of the total composition.

In a second aspect, the present invention provides use of starch and isopropyl myristate, wherein the starch is present in an amount of 5 to 15% and isopropyl myristate in an amount of 0.30 to 1% by weight of the total composition for providing a conditioning benefit when applying a dry shampoo to hair.

These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims. For the avoidance of doubt, any feature of one aspect of the present invention may be utilised in any other aspect of the invention. The word “comprising” is intended to mean “including” but not necessarily “consisting of” or “composed of.” In other words, the listed steps or options need not be exhaustive. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Similarly, all percentages are weight/weight percentages unless otherwise indicated. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word “about”.

Numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated.

Detailed Description of the Invention

The dry shampoo according to the invention provides a cleaning product with improved conditioning benefits.

In a first aspect, the present invention relates to a dry shampoo composition comprising a base and a propellant. Preferably, the dry shampoo composition comprises 5 to 20% of the base, preferably 10 to 18%, more preferably 13 to 16%.

The base comprises starch and isopropyl myristate. The starch according to the invention includes starch derivates. Preferably the starch is selected from corn starch, tapioca starch, rice starch, and modified starch in particular, modified corn starch and tapioca starch. A preferred modified starch is aluminum starch octenyl succinate. The starch is present in a concentration of 5 to 15%, preferably at least 6%, more preferably at least 7%, still more preferably at least 8%, even more preferably at least 9%, but typically not more than 14%, preferably not more than 13%, more preferably not more than 12%, still more preferably not more than 11%, even more preferably not more than 10% or even 9% by weight of the total composition.

With a starch concentration of 5 to 15% by weight of the composition, the system is typically a cleansing system than a conditioning system. Isopropyl myristate is used in the present invention as a conditioning agent.

The isopropyl myristate is present in a concentration of 0.30 to 1%, preferably at least 0.35%, more preferably at least 0.40%, but typically not more than 0.95%, preferably not more than 0.85%, more preferably not more than 0.75%, still more preferably not more than 0.65%, even more preferably not more than 0.55% or even 0.50% by weight of the total composition.

Without wishing to be bound to a theory, it thought that starch and conditioning oils have an interaction. While starch absorbs fatty sebum, it also inhibits conditioning oils. Wth isopropyl myristate there is an unexpected benefit at high starch concentrations and very low isopropyl myristate concentrations as defined herein, while at higher isopropyl myristate concentrations the benefit does not occur. There is thus provided, in a second aspect, the use of starch and isopropyl myristate, wherein the starch is present in an amount of 5 to 15% and isopropyl myristate in an amount of 0.30 to 1% by weight of the total composition for providing a conditioning benefit when applying a dry shampoo to hair. Preferably, the dry shampoo composition of the present invention comprises an anti caking agent which is preferably silica. Preferably, the anti-caking agent is present in the base from 0.1 to 1% by weight of the total composition.

Preferably, the dry shampoo composition of the present invention comprises an alcohol which is preferably ethanol. Preferably, the alcohol is present in the base from 0.5 to 20% by weight of the total composition.

Optional ingredients present in the base includes propylene glycol, fragrance, emotives.

The dry shampoo composition of the present invention comprises a propellant which serves to expel the base materials from the container. The propellant used in the present invention can be any liquefiable gas conventionally used for aerosol containers. Examples of suitable propellants include dimethyl ether and hydrocarbon propellants such as propane, n-butane and iso-butane.

The amount of the propellant used is governed by normal factors well known in the aerosol art. For dry shampoo compositions, the propellants are preferably present from 30% to 98%, preferably 33% to 90 %, more preferably 45% to 85%, even more preferably 55% to 85% by weight of the total composition.

The invention will now be further described by reference to the following Examples. In the Examples, all percentages are by weight based on total weight, unless otherwise specified.

Examples Example 1 : Effect of the composition on conditioning benefits

Hair switches were washed with the compositions in table 1 using the shampooing protocol mentioned below.

Table 1 Shampooing Protocol

All applications of dry shampoo formulations were carried out under controlled conditions of 20 degrees and 50 % RH.

Dry shampoo was applied by using a custom made, build in-house automated aerosol spray rig, which was designed to standardize the dosing of sprays onto the hair substrates. A switch of hair was placed onto the switch holder and bottom of the switch was clamped to secure the switch in position. The hair switch was sprayed with dry shampoo from 20 cm distance with spray rate of 1 g/s. The dose of dry shampoo was 0.1 g of the product per gram of hair. The hair switch was sprayed twice, half of the dose was applied and then the hair switch was rotated by 180 degrees by air piston and the other half of the dose was sprayed on the other side of the switch. The switch was left to equilibrate with product on for an hour before the measurement.

Friction was measured using the texture analyser to obtain the dry friction value.

Friction measurement methodology All friction measurements were carried out under controlled conditions of 20 degrees and 50 % RH.

Friction was measured using a TA.XT2i Texture Analyser supplied by Stable Micro Systems, Surrey, UK. The friction probe was a stainless-steel cylinder, which was coated with rubber material. The load on the friction contact was approximately 560 g. When in use, an area of contact between the friction probe and the hair of approximately 1.0 cm ² was achieved.

The methodology used to assess the friction properties of hair treated with test formulations was as follows:

A switch of hair was securely mounted onto the texture analyser, the hair fibers being aligned by combing before being secured in a flat configuration. The friction probe was placed onto the hair and moved along the hair at a speed of 10 mms ¹ to measure the friction between the probe and the hair.

The friction values reported below are of friction hysteresis in units of g.mm, obtained by integrating the total measured friction force over the total distance travelled by the probe, with and against cuticle. Two measurements were performed per switch (one up and one down the hair switch) and 5 switches per formulation were tested. The values reported are the mean values derived from these ten readings per treatment. Table 2

The above table shows that at 1.8 wt% of starch, the friction reduces with increase in isopropyl myristate as expected. However, when the concentration of starch is increased to 5.6 wt%, friction reduction can be noticed only up to 1wt%. The friction increases at 1.5% isopropyl myristate.