Composition

A solid composition comprising PA0 a. about 5 to 85 wt % of an acylisethionate salt, PA0 b. about 90 to 5 wt % of soap, and PA0 c. an effective amount of a metal chelating agent consisting solely of an agent selected from the group consisting of ethylene diamine tetra acetic acid, water soluble salts of said acid, and mixtures thereof, said composition having a pH of from about 7.2 to 10.

BACKGROUND OF THE INVENTION 
Acyl isethionate salts have been utilized for many years as surfactants in 
body care compositions. They are generally used in combars or synthetic 
detergent bars where their increased mildness in relationship to soaps are 
an advantage. The stability of these compositions under aging conditions 
such as shelf life have been studied for some time. Various antioxidants 
have been placed into soap and acyl isethionate compositions in order to 
provide increased stability under shelf life conditions. Various 
references are known which discuss the utilization of antioxidants to 
enhance shelf stability. Some of these antioxidants are known free radical 
scavengers which stop deterioration causing reactions from occurring. 
Examples of such antioxidants are butylated hydroxy toluene, (BHT) and 
butylated hydroxy anisole (BHA). Additionally it is well known that 
certain metals catalyse reactions which bring about the deterioration of 
the bar. Examples of such metals include iron and copper. Various 
chelating agents have been utilized to remove the metallic ions from 
interacting as a catalyst for the deterioration causing reactions. 
Examples of such materials include ethylene diamine tetra acetic acid 
(EDTA) or a soluble salt thereof such as a tetrasodium salt. A further 
chelating agent is 1-hydroxy ethane-1,1-diphosphonic acid (EHDP) or a 
soluble salt thereof. 
It is known to add such agents to acyl isethionate containing personal care 
compositions to improve their storage properties, for example see UK 
1169551 issued to Unilever. 
A recent Unilever patent issued by the European Patent Office subject to 
opposition, EP249474B1, has investigated the shelf stability-deterioration 
reactions of acyl isethionate further. It has made a study of the usage of 
the various antioxidants i.e. the 2,6 di-t-butyl-4-hydroxy toluene, 
previously referred to as BHT, as well as the usage of chelating agents in 
acyl isethionate containing compositions. At the bottom of page 2 of the 
published specification is the following paragraph: 
A preferred sequestering agent for copper is ethylene diamine tetra acetic 
acid (EDTA) or a soluble salt thereof such as its tetra sodium salt or 
mixtures thereof. Such agents are known to enhance the activities of iron 
in accelerating autoxidation, however it can be used successfully provided 
there is a satisfactory sequestering agent for iron present. The two 
sequestering agents are then acting synergistically. 
Therefore even though EDTA is known to be a chelating agent in general for 
various metallic ions, its use alone in acyl isethionate compositions is 
cautioned against because it accelerates autoxidation; one of the 
important reactions which brings about deterioration of a detergent 
composition and, interalia, a bad odor. 
It has now been surprisingly found in view of this statement in EP249474 
that EDTA and/or its soluble salts can be utilized successfully in acyl 
isethionate containing compositions of a certain nature. Thus, the usage 
of additional chelating agents is unnecessary. The usuage of only EDTA 
and/or its soluble salts brings about a stable composition. 
SUMMARY OF THE INVENTION 
In accordance with the invention there is a solid composition comprising: 
a. about 5 to 85 wt % of an acyl isethionate salt. 
b. about 90 to 5 wt % of soap, and 
c. an effective amount of a metal chelating agent consisting solely of an 
agent selected from the group consisting of ethylene diamine tetra acetic 
acid, water soluble salts of ethylene diamine tetracetic acid, or mixtures 
thereof, said composition have a pH of from about 7.2 to 10.

DETAILED DESCRIPTION OF THE INVENTION 
Any of the acylisethionate salts normally employed in personal cleansing 
compositions and laundry detergents can be employed in this composition. 
Acyl group having unsaturated or preferably saturated groups with normal 
or branched, preferably normal, groups can be used. Generally, the acyl 
groups have from about ten to twenty carbon atoms, preferably twelve to 
eighteen carbon atoms. The acyl group can be mixtures of acyl groups of 
these carbon lenghts as normally found in naturally products. Examples of 
such acyl groups are lauryl, cocoyl, plamitoyl and the like. The acyl 
group from coco fatty acid is preferred. The cation portion of the salt is 
generally an alkali metal such as sodium or potassium, ammonium, or an 
alkoxy substituted ammonium such as triethanol amine. Ammonium and sodium 
are preferred. 
Soap is the second necessary component in the composition. Any traditional 
soap such as a long chain fatty acid salt can be employed. 
The quantities of acylisethionate salt and soap which can be employed are 
from about 5 to 85 wt % acylisethionate salt and 90 to 5 wt % soap as 
measured by the solid composition. The preferred ranges are those that 
reflect a combar composition or a syndet composition. For example, in a 
combar about 6 to 25 wt % acylisethionate salt and 35 to 70 wt % soap is 
preferred. In a syndet composition about 25 to 60 wt % acylisethionate and 
5 to 20 wt % soap is preferred. 
The pH of the solid composition is significant. It should be on the basic 
side of neutral, generally pH of about 7.2 to 10, preferably about 7.2 to 
9.5. The pH is measured by making a 1 wt % solution of the composition in 
water and utilizing a Corning pH meter 120. 
It has been surprisingly found that solid cleansing compositions as 
disclosed above can be sucessfully stabilized against oxidative type metal 
catalyzed reactions which bring about undesirable odors to the composition 
by the addition of only a single type of chelating agent-ethylene diamine 
tetracetic acid (EDTA) and/or any of of its water soluble salts or 
mixtures thereof. Examples of such water soluble salts are the tri and 
tetra alkali metal salts such as sodium ethylene diamine triacetate or 
sodium ethylene diamine tetraacetate. 
The quantities of the chelating agents are not unduly significant. Any 
quantity of agent which successfully removes metal ions, particularly iron 
and copper, from catalyzing undesirable odor causing reaction(s) can be 
employed. Generally above about 0.002 wt % of the bar composition can be 
employed, preferably above about 0.02 wt %. Although not critical, 
quantities above about 0.5 wt %, preferably above about 0.3 wt % should 
not be employed primarily because of economics. 
The EDTA and/or its water soluble salts successfully remove cations, 
particularly iron and copper from participation in reactions, particularly 
those of an odor causing nature, thereby enhancing shelf stability of a 
solid personal cleaning composition of the nature described. 
Various other additives can also be present in such composition but are not 
required. Examples of such materials are fragrances, colorants, 
antibacterials, additional surfactants such as nonionic, zwitterionics, 
amphoterics, and the like. Free fatty acids can also be present for among 
other purposes, lather performances and skin feel. Of course, further 
stabilizing materials such as an antioxidant, for example butylated 
hydroxy toluene, (BHT) are preferably present in the composition for 
enhanced stabilization. Quantities of BHT can vary from about 20 ppm to 
400 ppm of the composition.