GB2451885A

GB2451885A - A cap comprising a chemically non-bonded acid, for use in neutralizing ammonia released during hair coloration

Info

Publication number: GB2451885A
Application number: GB0716009A
Authority: GB
Inventors: Eleonore David; Caroline Michenot
Original assignee: Givaudan SA
Current assignee: Givaudan SA
Priority date: 2007-08-16
Filing date: 2007-08-16
Publication date: 2009-02-18
Also published as: GB0716009D0

Abstract

A cap, e.g. a mobcap, comprising an acid which is chemically not bonded thereto, may be used to neutralize ammonia released during hair coloration by: <SL> <LI>(a) applying to hair an oxidative dye composition comprising aqueous ammonia and <LI>(b) subsequently cover the hair with such a cap. </SL> A package comprising such a cap and an oxidative hair colorant product is also provided. Suitable acids include citric acid, formic acid, lactic acid, acetic acid, malic acid, hypochloric acid and sulphuric acid. The cap may comprise an absorbent layer, e.g. of a cellulosic (such as paper), wool, cotton or suitable polymeric material. The cap may also comprise a pH-sensitive colour indicator (to indicate when the hair colouration process has finished), a perfume and a malodour counteracting agent.

Description

MOBCAP

The present invention relates to a cap suitable for the neutralization of ammonia released during hair coloration, in particular oxidative hair colorations.

The most commonly used method of dyeing hair, particularly human hair, is oxidative dyeing, in which a mixture of essentially colorless aromatic compounds, generally diaminobenzenes, dihydroxy benzenes and aminophenols, are converted by chemical reactions that are well known to those skilled in the art, to a blend of colored JO compounds within the hair fibers. Shortly before use, the colorless aromatic compounds, in a suitable base formulation, are normally mixed with hydrogen peroxide or other strong oxidizing agents. To increase the penetration of the dye into the hair fibers, the majority of products on the market further comprise ammonia, which is highly volatile and possesses an unpleasant odor even at very low concentrations.

Numerous attempts have been made to decrease the malodour perception of such *::::* products by replacing the ammonia with less volatile actives or by admixing odour masking agents to the product. However, up to now, an adequate replacement of *.*.. ammonia has not been found. All suggested substitutes result in poorer performing coloration and thus ammonia is still the compound of choice. Due to the fact that ammonia is a very volatile molecule having a very low odor threshold, this molecule will always be perceived immediately by the human nose, even at very low concentration in *. .: the ambient air.

Accordingly, there is a continued need in the art to improve on the odour perception of oxidative hair colorant products, which do not suffer from the drawbacks quoted above.

It has now been found that by covering hair to which hair coloration comprising ammonia is applied with a cap comprising an acid, the evaporation of ammonia can be almost eliminated due to neutralization of the ammonia by the acid.

Accordingly, the present invention refers in one of its aspects to a process of neutralizing ammonia comprising: a) applying to hair an oxidative dye composition comprising aqueous ammonia; and subsequently b) covering the hair with a cap comprising an effective amount of acid, the acid being in contact with the ammonia released into the vapor phase during the dyeing process.

The cap for use in the present invention may be made of any convenient material. It is usually a polymeric material, typically a polyolefin (such as polyethylene, polypropylene, or polyethylene tetraphtalate) or nylon, but other suitable polymers with the necessary flexibility and ability to comprise the effective amount of acid may be used. The material of the cap may comprise a single material that either is able inherently to retain the acid, or which can in some way be modified or treated to be able to do so. For example, in the case of a polyolefin, the surface of the material that will be adjacent to the hair when the cap is worn may be suitably treated or modified to enable acid retention.

Alternatively, the cap may be made of a layered material, comprising a non-woven layer and an absorbent layer, arranged so that the absorbent layer is on the inside of the cap.

The absorbent layer may be of any suitable material, for example a cellulosic material such as paper, a natural absorbent material such as wool or cotton, or an absorbent * .1 layer of any suitable polymeric material.

The term absorbent material" as used within the present invention refers to materials such as cellulose and cotton which are suitable for the preparation of thin layers or *..: sheets suitable for further processing caps, such as mob caps, bouffant caps or shower caps.

Thus, the present invention refers in a further aspect to a cap comprising an effective amount of acid which is chemically not bonded.

Suitable acids may be selected from any organic and inorganic acids, such as citric acid, formic acid, lactic acid, acetic acid, malic acid, hypochloric acid and sulfuric acid, or mixtures thereof. Preferably, the acid is an organic acid.

The acid may be applied to the cap material by any suitable means, for example, by spraying or immersion, followed by any necessary washing, rinsing or drying. If an absorbent material is used, the acid may be applied by simply preparing a solution comprising the acid, which is then sprayed on to the absorbent material, or the absorbent material is immersed in the solution. The solvent is then removed by drying the material with means known to a person skilled in the art. Suitable solvents include water and alcohol (e.g. ethanol).

The amount of acid present in the cap to be effective mainly depends on the ammonia concentration present in the hair colorant and the acid used, and may easily be calculated by a person skilled in the art. For example, based on the assumption that one average portion (which is about 50g) of hair colorant product comprises from about 0.2 to about 2g of ammonia, the cap of the present invention may comprises from about 0.005 to about 0.35g of citric acid, preferably from about 0.07 to about 0.25g.

A cap may be manufactured either before the acid is applied to the cap material or after the acid is retained in the cap material. *. * . * *.*

*.** . . . . . . . . In addition, the cap may retain other ingredients including pH-sensitive color indicator, perfume, and malodor counteractants, known to the person skilled in the art. * ** * * * * **

Suitable color indicators are bromocresol green, thymolphtaleine, cresol red, methyl red and bromophenol blue. The color indicator in combination with the acid may be used as *S** an indicator of when the hair coloration process is finished.

The term "malodor counteractant" as used herein refers to compounds capable of interacting with malodor compounds in such a way as to alleviate the offensiveness of the malodor as perceived by the human sense of smell, but does not include acids as hereinabove defined. Suitable compounds and mixtures thereof are disclosed, for example, in WO 02051788, which is incorporated herein by reference.

In a further embodiment, the present invention refers to a package comprising a) an oxidative hair colorant product, b) a cap comprising an effective amount of acid, and optionally a color indicator, perfume, and/or malodor counteractants.

The invention is now further described with reference to the following non-limiting examples. These examples are for the purpose of illustration only and it is understood that variations arid modifications can be made by one skilled in the art.

Example 1:

The following dye composition was prepared: Phase A weight % Delonised water 57.85 Carbomer (CarbopolTM U 10 from Noveon) 0.20 Propylene glycoT 3.00 Sodium metabisulfjte 0.45 Sodium cetearyl sulfate 1.00 IS Phase B Cetearyl alcohol (LanettoTM 0 from Cognis) 5.00 Glycoldistearate 1.00 Ceteareth-25 (SympatensTM ACS/250 from KOLB) 1.60 * I. Laureth-4 (SympatensTM ALM/040 from Kolb) 2.90 Laureth-23 (SympatensTM ALM/230 from Kolb) 1.00 Palmitic Acid 5.00 S... * * *...

*:*. Phase C Silica dimethyl silylate (CovasilicTM 15 from LCW) 1.00 Phase D Triethanolamine qsp pH = 8 (4.5%) Phase E Deceth-3 (EumulginTM BL 309 from Cognis) 7.50 Ammoniac (20%) 12.00 Phase F Perfume 0.50

S

Phases A and B were heated separately at 80°C under stirring. Silica dimethyl silylate (phase C) was then added to phase B under stirring, followed by the addition of phase A. The resulting mixture was allowed to cool down to 40°C and then adjusted to a pH of 8 with phase D. Shortly before use phase E and F were subsequently added.

S

The cap, in accordance with the invention, was prepared by spraying homogenously 0.5g of an acidic solution comprising citric acid, ethanol and a color indicator according to the formulation given below. A blank cap, i.e. a paper cap to which no acidic solution was added, was used as comparison.

Acidic solution Dart /weiQht Citric acid at 50% aqueous solution 30.00 Bromocresol green 0.15 Ethanol 69.85

IS * * * *.*

50g of the dye composition as described above was mixed at the time of use with 50g aqueous hydrogen peroxide solution in a bowl. The blank cap and the cap in * .* accordance with the invention was then put on the top of the bowl and the odor of the paper was evaluated over a period of 30 minutes, which is the average setting time for an oxidative dyeing process, every 10 minutes. In addition, the color of the paper was S*I observed over time. S. * * S * * SS

Results: A) cap in accordance with the invention During a setting time the cap changed the color, going from yellow to blue. No ammonia odor was noticed by the panelists over the whole evaluation time. Even when the cap was taken off at the end of the setting time, there was no ammonia boost, which means that the ammonia was neutralized by the acid present in the cap and not only kept underthe cap.

B) blank cap At the initial time no ammonia odor was noticed. But 10 minutes later there was a strong ammonia odor noticed by the panelists, which slightly decreased over the total setting time. When the cap was taken off at the end of the setting time, there was still ammonia odor noticeable.

Further details are given in Table 1 below.

Table 1: Ammonia intensity riie (minutes) Ammonia intensity (arithmetic mean) fl Cap with acidic solution Blank cap _____________ 0 1.5 (io 0.17 3.67 0.17 3.67 0.83 3.0 jig off the cap after 30 minutes 0.5 3.0

_________________________

The odor was evaluated by 3 to 4 experts using the following 6 point scale: 0= no ammonia odor, 1= odor barely perceivable, 2= weak odor but perceivable, 3= easily perceivable, 4= strong odor, 5= very strong odor. The experts were also allowed to use : ... interim values such as 0.5, 1.5, or 2.5. *5IS * . S...

&mDle2: * S. 50g of the dye composition from Example I was mixed at the time of use with 50g aqueous hydrogen peroxide solution in a bowl. The mixture was then applied on hair of S.. a test person. Finally, a cap in accordance with the present invention was put on the head of the test person. The cap was prepared by homogenously spraying 0.5g of an * acidic solution comprising citric acid, ethanol, color indicator and perfume on a commerciaIlyavaiIable cap made of cellulose. Before use the cap was allowed to dry at room temperature Acidic solution oart /weigt Citric acid at 50% aqueous solution 30.00 Bromocresoi green 0.15 Ethanol 69.85 The odor in the ambient air near to the head of the test person was evaluated over a period of 30 minutes, which is the average setting time for an oxidative dying process, every 10 minutes. In addition the color of the cap material was observed over time.

Results: During a setting time of 30 minutes the cap changed the color, going from yellow to blue. No ammonia odor was noticed by the panelist over the whole evaluation time.

Even when the cap was set off at the end of the setting time, there was no ammonia boost, which means that the ammonia was neutralized by the acid present in the cap and not only kept under the cap. * S * *** *..S * S **.* * S. * S * * I. 0SS* * S S.. S. S

S S **

Claims

Claims 1. A cap comprising an acid which is chemically not bonded thereto.
2. A cap according to claim 1 wherein the acid is an organic acid.
3. A cap according to claim 1 wherein the cape is made of cellulose.
4. A cap according to any one of the preceding claims further comprising a color indicator.
5. A method of neutralizing ammonia released during hair coloration comprising applying to hair an oxidative dye composition comprising aqueous ammonia and subsequently covering the hair with a cap as defined in any one of the preceding claims.
6. A method according to claim 5 characterized in that the cap comprising an effective *:: amount of acid, the acid being in contact with the ammonia released into the vapor phase during the dyeing process. * *l * * * * .*
7. A package comprising a) an oxidative hair colorant product, b) a cap as defined in any one of the claims 1 -4. ** * * * * * *.