AU637668B2 - Detergent composition - Google Patents

Description

637668

AUSTRALIA

PATENTS ACT 1952 Form COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE Short Title: Int. Cl: S S *5*S

S

OS S S

S.

5.55

S

S..

Application Number: Lodged: Complete Specification-Lodged: Accepted: Lapsed: Published: Priority: Related Art: TO BE COMPLETED BY APPLICANT Name of Applicant: Address of Applicant: 595855 5 *5*5 S 5.

SS S S. S

S

S.

UNILEVER PLC UNILEVER HOUSE

BLACKFRIARS

LONDON EC4

ENGLAND

Actual Inventor: Address for Service: GRIFP i HACK CO. Ljni teJar_ hutfhn\ia LifYl Tc) 601 St. ilfda Road, cl rnr rjcr-ne Me urin'e 7 Vtcora---6O4, ThnuorG coi6 AM s4 e

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f 3 I '1 Complete Specification for the invention entitled: DETERGENT COMPOSITION.

The following statement is a full description of this invention including the best method of performing it known to me:- 89-0321-EDG DETERGENT COMPOSITION The invention relates to solid skin cleansing, detergent compositions containing acyl isethionates.

Traditionally, soap has been utilized as a skin cleanser. Soap is, however, a very harsh chemical.

Irritated and cracked skin result from use of soap, especially in colder climates. There are, however, certain benefits from the use of soap including low cost, ease of manufacture into bars, and good lathering properties.

o There has been much commercial activity in attempting S to replace soaps with milder surfactants. The introduction of mild synthetic detergent toilet bars, especially those based on sodium cocyl isethionates, has been particularly successful. Patents relating to this technology are dicussed in a published PCT application number WO 90/12860, which is incorporated by reference herein.

U.S. 4,335,025 discusses synthetic detergent bars containing critical amounts of components. For example, alkali metal salts of C8- 16 alkyl sulfosuccinate together with a selected water soluble anionic detergent which may include a C 10 16 acyl isethionate, a waxy extender such as a

C

12 22 fatty acid or alcohol and the like, and other -1optional extenders.

U.S. 3,901,832 discusses a detergent bar containing a monoalkyl sulfosuccinate and a specific plasticizer in detergent cakes.

U.S. 3,989,642 discusses a synthetic toilet bar containing selected amounts of an alkane sulfonate, a fatty acid, and a binder modifier, which may be an alkyl sulfosuccinate.

U.S. 4,812,253 discusses various compositions containing polymeric skin mildness aids, moisturizers, soap and selected surfactants which include acyl isethionates and alkyl sulfosuccinate.

.The present invention aims to provide compositions with excellent skin mildness while also possessing good lather, 96 mush and processing properties.

According to the present invention there is provided a skin cleansing toilet bar composition comprising: i) acyl esters of isethionic acid salts, the acyl chain length distribution of said esters being at least about 90% C 6

-C

18 and having more than about 30% C14 or lower; and ii) at least one sulfosuccinate wherein the weight ratio of said acyl esters to sulfosuccinate is 10:1 to 2:1.

Preferred skin cleansing compositions have acyl isethionates as the main active in combination with monoalkyl sulfosuccinates as the co-active. Such compositions can be substantially milder to the skin than previously known compositions.

Compositions within this invention may contain some free fatty acid. They may contain some free isethionate.

They may contain some soap.

A preferred solid skin cleansing composition comprises: acyl esters of isethionic acid salts in an amount of 20 to at least one sulfosuccinate wherein the weight ratio of said acyl esters to sulfosuccinate is 10:1 to 2:1; (iii) free fatty acid in an amount of 2-40%; (iv) free not esterified) isethionate salt in an amount of 2-20%; soap in an amount of 0-25%; (vi) water in an amount of 2-20%; (vii) miscellaneous other constituents in an amount of 0-20%.

Preferred weight ratios of acyl isethionate to sulfosuccinates are 6:1 to 2:1 and most preferred to maintain mildness are 2:lor 3:1 up to 4.5:1.

I I In this invention, the irritancy of the already mild main active, acyl isethionate, can be reduced significantly by the incorporation of sulfosuccinates.

The cleansers resulting from this mixture of actives have superior skin mildness together with good bar properties such as processability, low mush, good lather, and good tactile characteristics. In addition, they are easily processable using standard manufacturing equipment.

In order for processability to be good, it is usually required for the composition to have an appropriate hardness and stickiness.

Isethionate salts in the range of about C 6

-C

1 8 such as those derived from coconut fatty acids, for example, have been employed in a number of commercial cleansing products and are known to produce a voluminous, creamy lather. This active, by itself, has been shown to be very mild to the skin. These actives are solid at room temperature and serve as excellent structurants when used in bar formulations.

A preferred isethionate ester salt for use in this invention is the cocoyl ester. This ester may be prepared from the usual cocoyl fatty acids having a small percentage of fatty acid chains below C 8 with over 95% of the carbon chain distribution being between C 8 and C 18 and more than L, half being C12 or less.

A typical cocoyl fraction will contain: Wt.% Fatty Acid Combined Chain Length As Cocoyl Isethionate

C

6 10 10-25

C

12 45-55

C

14 18 20-40

C

18 unsaturated 1-15 Skin testing has shown that the mixed active system of this invention significantly reduced the irritancy of the already mild acyl isethionate base. Skin testing and use *er. property evaluation have shown that the preferred ratio of isethionate to sulfosuccinate is 2:1 to 6:1.

The sulfosuccinates useful in the invention may be any suitable sulfosuccinate esther mono-esters (half esters) or di-esters and any alkali metal, alkaline earth metal or ammonium salt, but the sulfosuccinates are preferably monoesters and preferably prepared through an alkanolamine intermediate so as to introduce an amido group into the molecule. Preferably to give processability, mildness and other use properties the sulfosuccinate monoester is prepared through a monoethanolamine intermediate.

89-0321-EDG The most preferable sulfosuccinates are, Disodium Cocamido Monoethanolamide Sulfosuccinate of the Structure 1: O NJ 0 0 C MH CHS.- CHI-- C /0-N 1 R in Structure 1 is derived from coconut fatty acids, but in other forms may be any convenient alkyl group. The chain length distribution of coconut fatty acids is similar to that for the coco group on the isethionate. The chain length distribution will contain at least 90% of C 8 to C 18 with more tham half made S up of C 8 to C 1 4 A typical fatty acid distribution in the cocoyl portion is as follows: i Weight Fatty Acid Combined As Chain Length Cocoyl Amido Sulfosuccinate

C

6 10 10-25

C

12 45-55

C

14 18 20-40 C18 unsaturated 1-15 18 89-0321-EDG The sulfosuccinate of Structure 1 may conveniently be prepared by a two step reaction: 1. An ester condensation reaction of Coco alkanolamide with Maleic Anhydride.

Sulfonation of the double bond with Sodium Sulfite as described below.

89-0321-EDG Preparation of Disodium Cocamido Monoethanolamide Sulfosuccinate a) preparation of the coco-fatty ethanolanmide ,0 0 R-C NH 2-OH 2-H R-C-NH-CH2 -CH 2

-OH

OH

coco fatty acid ethanol coco fatty ethanolamide

H

2 0 water S S S S 55 S S S S *5 S 5 5 55 505 S S S.

S S S S S 55 S S 5 0 S S S S 5 555 S 89-0321-EDG b) ester condensation reaction of maleic anhydride and the coco ethanolamide R- -NH-CHf-

CH

2 7-OH 0 Cui-C' 1C-NH-C 2

H

4 -O8CH-CH=C

O

coco fatty ethanolaricte maleic anhydride (molar excess) 1. 70-100C monoester 2. catalyst 3. 2 hours water c) sulfonation with sodium sulfite (See Step b) bla 2so3 (Structure 1) aqueous monoester sodium sulfite disodium cocamido mea sulf-:uccinate solution 89-0321-EDG The relative amounts of isethionate esters to sulfusuccinate will preferably lie in the weight ratio of 2:1 to 4.5:1, or even as'high as 6:1, preferably from 3:1 to 4:1, optimally about 3.5:1.

As previously noted, soap may be somewhat harsh and when present in the compositions of this invention should be at a level no higher than about 25%, preferably less than and advantageously totally absent.

Free fatty acids of about 8-22 carbon atoms are desirably incorporated within the compositions of the present invention. Some of these fatty acids are present to operate assuperfatting agents and others as skin feel and creaminess enhancers. Fatty alcohols, fatty amides and the like may also be employed. Superfatting agents enhance lathering properties and may be selected from fatty acids of carbon atoms numbering 8-1i, preferably 10-18, in an amount up to 40% by weight of the composition. Skin feel and creaminess enhancers, the most important of which is stearic acid, are also desirably present in these compositions.

89-0321-EDG Other performance chemicals and adjuncts may be needed or employed with these compositions. The amount of these chemicals and adjuncts may range from about 0% to about 20% by weight of the total compositions. For instance, there may be included humectants such as glycerine; anti wear agents such as polymer JR and natural and synthetic gums and the like; germicides, perfumes, colorants, dyes, pigments such as titanium dioxide, electrolytes, and water.

8:79 Evaluation of an active's skin mildness properties are determined through the following test procedure.

S

o -11- 89-0321-EDG The Flex Wash Test The products skin mildness properties were evaluated by comparison to Dove toilet bars (Dove is a registered trademark of .o Lever Brothers which are very mild commercial bars, through the following test procedure. The Flex Wash test procedure *4G@ o consists of three daily two minute washes of the antecubital fossa (flex area of elbow). This method is an "exaggerated use" method designed to differentiate very mild products. Erythemal response varies only slightly with temperature and humidity fluctuations making the protocol suitable for year round testing.

Approximately 15 panelists were used as the test

S

population. Panelist flex areas must be free of any skin condition (eczema, dryness, irritation, cuts or abrasions).

Anyone taking antihistamines, anti-inflammatory drugs (more than 8 per week) or topical, oral or injectable cortisone on a regular y basis was excluded from the study. The panel was divided into two sub-groups which were balanced for left handedness. Group I was assigned composition for the left flex and for the right flex. Group II reversed the order.

-12- 89-0321-EDG Following an evaluation, the panelist was instructed to moisten the left flex area, the sponge and test compositions formulated as toilet bars were dampened with tap water (100 ppm calcium/magnesium ions). The sponge was then stroked over the test bar 10 times by the evaluator. The "dosed" sponge was placed in the panelist's right hand. The panelist then washed the left flex area for exactly two minutes. Thereupon, the flex was rinsed and patted dry. This washing procedure was repeated

O**

on the right arm with the appropriate composition. Thus, both arms are tested simultaneously. Washing by this procedure was repeated three times daily for 5 consecutive days for a total of washes. Treatment times were scheduled 1.5 hours apart. Each Aa*UB test site was evaluated immediately prior to washing and 4 hours ar after the third daily wash.

-13- 89-0321-EDG One trained assessor evaluated test sites prior to each wash and 4 hours after the third wash of the fifth day for a total of 15 evaluations. The grading scale was as follows: S0 no erythema at 9 *,on 0.5 barely perceptible erythema 1 mild spotty erythema/no edema 1.5 mild/moderate erythema/with or without edema 2 moderate confluent erythema/with or without edema or vesiculation Each test site was treated in the prescribed method until a grading of or greater was attained or 15 washings had 0 been completed. When a score-of or greater was attained, the treatment was discontinued on that flex. The final score was then carried through for all remaining evaluations. The remaining flex was washed until either a grading of at least "2" or 15 treatments were attained, whichever was first. In the Examples of this specification, the final grading, Mean Rank Scores, is the sum total of grade scores for 15 assessments per panelist averaged over the scores from all panelists. Thus, theoretically, the average score could range from 0 to 30; the lower score indicating absolutely no skin irritation while the -14- 89-0321-EDG score being the most severe. Mean Endpoint Erythema scores are the mean of the evaluation scores, for each panelist, at which the first arm received a grade of or greater erythema score or at the completion of fifteen washes.

The following examples will more fully illustrate the embodiments of this invention. All parts, percentages and proportions referred to herein and in the appended claims are by weight of the total composition unless otherwise stated.

e aJ :00 89-0321-EDG EXAMPLE 1 This example illustrates the difference in mildness between Dove and a toilet bar employing the hcyl Isethionate/Alkyl Sulfosuccinate active system, where the ratio of Isethionate to Sulfosuccinate is 2.20:1.

7*Formulation 1 0 00 sodium Cocoyl Isethionate 33.10 Stearic Acid 29.80 *Sodium Isethionate 9.10 Disodium Cocamido MEA Sulfosuccinate 15.00 Water 10.00 *Perfume 1.00 Sodium Chloride .0.35 **.:Titanium Dioxide 0.20 Miscellaneous 1.45 -16- 89-0321-EDG Flex Wash Mean Endpoint -Erythema Mean Rank S core Formulation 1 Dove 0.794 1.735 10.79 24.21 S 0SS*

S.@

3 5 S SO S. S S S *5 9 @5~5

S

SS*

Statistical Analysis Rank Scores: P 0.0000 (Wilcoxon 2 sample) 5555**

S

5.5.

5* *5 S S 55 9

S

-17- 89-0321-EDG EXAMPLE 2 The addition of small amounts of PEG-l50, a polymer of ethylene oxide, does not deteriously affect the mildness of a 2.87:1, Isethionate to Sulfosuccinate, formulated toilet bar.

*Formulation 2 foe* fSodium Cocoyl Isethionate 43.6 *Stearic Acid 22.0 Sodium Isethionate 9.3 Disodium Cocamido MEA Sulfosuccinate 15.2 Sodium Chloride 2.6 PEG 150 see@*: Water 4.7 Perfume 0. Titanium Dioxide EHDP 0.02 555EDTA 0.02 Carbowax 8000 (Union Carbide) -18- 89-0321-EDG Flex Wash Mean Endpoint Erythemna see f:.

a 6 000 Mean Rank Score 14.08 22.92 Formulation 2 Dove 0.69 1.05 Statistical Analysis Rank Scores P =0.0096 (Wilcoxon 2 sample) 00 so.

*fee 89-0321-EDG EXAMPLE 3 In the following example, mildness superior to that of Dove is again demonstrated. The Isethionahe to Sulfosuccinate ratio here is 2.89:1.

Formulation 3 *Sodium Cocoyl Isethionate 43.9 *seStearic Acid 20.1 se Sodium Isethionate 11.0 Disodium. Cocamido MBA Sulfosuccinate 15.2 Sodium Chloride 5.1 *Water 3.2 Perfume :Titanium Dioxide J EHDP 0.02 EDTA 0.02 89-0321-EDG Flex Wash mean Endpoint.

Erythema 0.8 1.5 Mean~ Rank Score 12.29 22.71 Formulation 3 Dove 0SO* S. S S

S.

Sesh

S

OSSS

.5 0 Statistical Analysis Rank Scores P 0.0018 (Wilcoxon 2 sample)

S

.4 S* S Se 09 S S. S S S S k) 55 -21- 89-0321-EDG EXAMPLE 4 In this example, the ratio of Cocoyl Isethionate to Amido Sulfosuccinate is 3.64:1. Mildness, superior to Dove, is proven by the Flex Wash.

Formulation 4 Sodium cocoyl Isethionate 43.7 S0 Stearic Acid 23.9 00*0Disodiun Cocamido :0 MEA Sulfosuccinate 12.0 Sodium Isethionate 13.8 Water 4.7 Perfume Sodium chloride 0.35' Titanium Dioxide .EHDP 0.02 )EDTA 0.02 -22- 89-0321-EDG Flex Wash Mean End~point -Erytheyfa Mean Rank Score For1L,-.-kation 4 Dove 0.9 1.6 12.56 22.44

S

*5*S 0 @0 S S

S.

S. OS

S

S

S 550 Statistical Analysis Rank Scores P 0.0027 (Wilcoxon 2 sam~ple)

S

00@055

S

5* SS S S. S S S

~S

5555 55*5 -23- 89-0321-EDG EXAMPLE A significant improvement in mildness over Dove, at the confidence level, is achieved when the isethionate to sulfosuccinate ratio is 5.12:1. The Mean Endpoint Erythema is substantially lower in the mixed active, Isethionate/ S Sulfosuccinate bar, than in Dove.

Formulation e* Sodium Cocoyl Isethionate 46.1 Stearic Acid 23.7 Disodium Cocamido MEA Sulfosuccinate Sodium Isethionate 13.7 PEG 150 Soc..ium Chloride 0.35 Water 4.7 Perfume Titanium Dioxide EHDP 0.02 EDTA 0.02 *Carbowax 8000 (Union Carbide) -24- 89-0321-EDG FleX Wash Mean Endpoint Erythema 0.8 1.27 Mean Rank Score 15. 69 21.31 Formulation 5 Dove 0

OS

Statistical Analysis Rank Scores: P 0.1028 *5 0

SB

OS

2 555,

S

89-0321-EDG EXAMPLE 6 Lather Volume measurements and bar mush evaluations were performed on the forementioned formulations. A brief description of the lather and mush tests are reported below.

0 Objective Lather Volume This test involved rotating the toilet bar 15 half turns under running 950 F water. The bar was then set aside and the resulting lather was worked by hand for 10 seconds. A measuring funnel was then placed over the

S

hands and both were lowered into a sink filled with water to the 0 ml mark on the measuring funnel. When the hands were fully immersed, they were removed from beneath the funnel. The funnel was then lowered to the bottom of the sink and lather vol.ume was measured.

Mush Pre-weighed bars were immersed in water for 2 hours. The increase in weight was noted. Mush was removed and the remainder of the bar was dried. After reweighing, mush was calculated as the weight of mush per 50 cm 2 of surface mushed.

Lower values indicated better performance.

-26- 89-0321-EDG TABLE 1 Acyl Isethioriate: Formulation Mono-AlkVl Sulfosuccinate Lather Volume (ml).

Mush (cf /50c2 S S S. S S S *5 5.55 0

S.

S

S..

1 2.20:1 125 2 2.87:1 135 9.45 3 2.89:1 150 8.22 4 3.64:1 160 7.15 5 5.12:1 160 6.54 Commercial Dove 150 8.25 All of the formulations in Table 1 have excellent lather and low bar mush values.

55 S S 55 0555 89-0321-EDG EXAMPLE 7 In the following example, six mixed active bars and commercial Dove, were panel tested. The panel consisted of highly discriminating female Dove users. Each panelist was asked to set a water temperature and then wet her hands. A bar was then taken from the soap dish, into both hands, lathered up, and 1 placed back into the dish. The panelist then rinsed her hands 0 and patted them dry with a non-woven towel. At the end of the wash the panelist was asked to complete a questionnaire. This process was repeated for each of the 6 remaining bars. The questionnaire was divided into two parts, the first part inquired about use properties and asked the panelists to judge the Ease of Lather Generation, Subjective Lather Volume, Lather Creaminess and Ease of Rinsing. The second part asked about skin after effects such as dryness, softness, irritation, smoothness, and cleanliness.

:Results of these tests show the Isethionate/ Sulfosuccinate combination has excellent consumer properties.

-28- 89-0321-EDG The test bars had the following compositions: Hand Wash Formulations

BAR,

Isethionate: Sulfosuccinate **:Sodium Cocoyl Tsethionate Stearic Acid sodium Isethionate Disodium.

Cocamido, MEA Sulfosuccinate *ee Sodium Chloride Carbowax 8000 :Perfume Titanium Dioxide

EDTA

EHDP

Water 2.87:1 2.88:1 5.19:1 3.64:1 5.12:1 3.59:1 43.6 22.0 40.9 23.7 46.7 23.9 43.7 23.9 46.1 23.7 43.1 23.7 Dove 9.3 13.7 13.8 13.8 13.7 13.7 15.2 2.6 1.0 1.0 0.5 0.02 0.02 4.7 14.2 0.35 1.0 1.0 0.5 0.02 0.02 4.7 9.0 0.35 0.0 1.0 0.5 0. 02 0.02 4.7 12 .0 0.35 0.0 1.0 0.5 0.02 0. 02 4.7 9.0 0.35 1.0 1.0 0.5 0. 02 0.02 4.7 12 .0 0.35 0. 02 0.02 4.7 -29- 89-0321-EDG Lather was evaluated based upon the following scale:

GRADE

9 8 7 6

DEFINITION

outstanding Excellent Extremely Good Very Good Good

GRADE

5 4 3 2 1

DEFINITION

Fairly Good Moderate Fairly Poor Poor Terrible a.

a S *655 a

S

55 S S a 4 55 Sega .55.

'S

S

S..

.00 4* to

@*ON

Bar 1 2 3 4 6 7 Ease of Lather Generation 6.80 8 27 7.67 8.00 7.60~ 7.20 8 .14 Mean Ratings Subjective Lather Volume 7 .07 8.27 7.27 7.93 7.20 7 .13 7.86 Lather Creaminess 7.67 8.47 7 .67 8. 07 7.93 7 .53 8.00 Ease of Rinsing 8. 13 7.60 8.00 8.27 7.93 7.33 7.79 89-0321-EDG These resulsts clearly show that bars 1 to as consumer acceptable as the commercial bar.

6 are quite Skin Afterfeel was evaluated based upon the following scale:

GRADE

9 8 7 6

DEFINITION

Fully Agree

GRADE

4 3 2 1

DEFINITION

Fully Disagree -31- 89-0321-EDG Mean R~ating~s Is Not Drying to the Skin Bar q* 4; *0 he 6* .e

C

C

a..

7.47 7.40 7 .73 8.00 7,.73 7.07 7 .07 Leaves Skin Feeling Sof t 8. 07 7 .67 7.80 7 .93 7.80 7.47 7 .57 Is Not Harsh or Irritatingr 8.00 8 .07 8.07 8.20 8 .07 8.00 7.57 Leaves Skin Feeling Smooth 8.20 8.33 8 .13 8.33 8 .07 8.07 7.57 Leaves Skin Feeling Clean 7.67 7 .93 8.27 8.00 7 .87 7.87 7.86 These results shoW that the combination of the invention is not only equal to the commercial bar, but in some cases, perceivably better.

N* C a 4 C.

9 a.

0 *r -32-

Claims (1)

1. 89-0321-EDG THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. A skin cleansing toilet bar composition comprising: i) acyl esters of isethionic acid salts, the acyl chain length distribution of said esters being at least about 90% C 6 -C 8 and having more than about 30% C 14 or lower; and ii) at least one sulfosuccinate wherein the weight ratio of said acyl esters to sulfosuccinate is 10:1 to 2:1. .a 4 o 2. A composition according to claim 1 wherein the a sulfosuccinate is a mono ester. 3. A composition according to claim 1 wherein the sulfosuccinate is derived from a monoethanolamide. a 4. A composition according to claim 2 wherein the sulfosuccinate is an amido sulfosuccinate. aS• A composition according to claim 4 wherein the sulfosuccinate is a cocoamido sulfosuccinate. 6. A composition according to any one of the preceding claims wherein the ratio of isethionate ester to sulfosuccinate is from 6:1 to 2:1. -33- 7. A composition according to any one of the preceding claims wherein the ratio of isethionate ester to sulfosuccinate is from 4.5:1 to 2:1. 0. A composition according to any one of the preceding claims wherein the ratio of isethionate ester to sulfosuccinate is from 4.5:1 to 3:1. 9. A composition according to any one of the preceding claims wherein said acyl chain is derived from cocoyl fatty acid having the following chain length distribution: wt% Fatty Acid Combined SChain Length as Cocoyl Isethionate C 10-25 6-10 C 12 45-55 .12 20 C 20-40 1 4 1 8 C18 unsaturated 1-15. A composition according to any one of the preceding claims wherein the amount of said acvl esters of 25 isethionic acid salts is 20 to 70% by weight of the composition. 11. A composition according to claim 0 which also comprises 2 to 40% of free fatty acid, 2 to 20% of 30 sodium isethionate and 2 to 20% by weight of water, the amount of soap in the composition not exceeding by weight and the amount of any other materials in the composition not exceeding 20% by weight. DATED THIS 29TH DAY OF MARCH 1993 UNILEVER PLC By its Patent Attorneys: GRIFFITH HACK CO Fellows Institute of Patent Attorneys of Australia. -34-