AU673536B2 - Personal cleansing bar - Google Patents

Description

-1- P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT

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Invention Title: PERSONAL CLEANSING BAR

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The following statement is a full description of this invention, including the best method of performing it known to us: a U GH&CO REF: P22958-A:VNV:RK ~o PERSONAL CLEANSING BAR The present invention relates to a personal cleansing bar, particularly but not exclusively to a soap-containing personal cleansing bar.

Soap bars, tablets and the like (all hereinafter referred to as bars) are of course used very extensively for personal cleansing purposes, e.g. washing, bathing and showering. There is however a problem with many existing soap bar formulations in that lte bar only generates a relatively low amount of lather during wasling and also has a tendency to produce relatively large amounts of "mush". Low lathering is a disadvantage because people tend to "like" the feel of lather and tend to feel that low lathering products do not cleanse effectively. The production, of mush is disadvantageous because the mush is felt to be unpleasant to the touch and also represents a loss of soap from the bar.

It is an object of the present invention to obviate or mitigate the abovementioned disadvantages.

According to the present invention there is provided a personal cleansing bar 15 comprising a surface active agent (other than (ii) below) suitable for personal washing purposes, and i (ii) the magnesium salt of a CIo-C, 5 straight chain alkyl sulphate.

The invention has been based on our discovery that the inclusion of the 20 magnesium salt of a straight chain Clo-C 5 alkyl sulphate in a cleansing bar provides S' high lathering performance and low mush during use of the bar. In addition, a particularly good feel is imparted to the skin both during and after washing with the bar.

Generally the bar will comprise 10-90% by weight of ite surface active agent and 1-40% by weight of the alkyl sulphate. More preferably the bar comprises 40- 7 0 0 by weight of the surface active agent and 10-25% by weight of the alkyl sulphate.

Typically the surface active agent and alkyl sulphate will together comprise up to about 85% (more preferably up to about 80%) by weight of the total weight of the cleansing bar. Other components which may be present in tie bar are those c- 4~ conventionally found in personal cleansing bars e.g. water, superfatting agents, perfume, dye, etc.

It is also preferred that the alkyl group has 11-13 carbon atoms. The most preferred alkyl sulphate for use in the invention is magnesium lauryl sulphate, ie.

C

1 2

H

25

OSO

3 Mg. Whilst magnesium latuyl sulphate (MLS) is preferred, it will be appreciated that commercially available MLS may contain a distribution of chain lengths but will be perfectly suitable for use in the invention.

The surface active agent used in the bar may for example be a synthetic S'detergent but is more preferably a soap.

The soap used in the bar may be a salt (particularly an alkali metal or ammoniumn salt) of a C-C22 fatty acid. Examples of such soaps are palm, tallow, coconut, and pahn kernel soaps. Particularly preferred for use in the invention are palm/nut oil and tallow/nut oil soaps. Generally the palm (or tallow):nut oil ratio will be in the range 90:10 to 10:90, more preferably 50:50 to 85:15.

15 The sodium salts of the soaps are preferred.

inlExamples of synthetic detergents which may be used in the surface active agent include acyl isethionates, alkylmethyl taurides, hydroxyalkylmethyl taurides, oleyamphopolycarboxyglyinates alkyl phosphonates and phosphates, and di alkyl sulphosuccinates, mono-alkyl sulphosuccinates, betaines, alkyl ether carboxylates, sultanes, alkyl ether sulphates, glutamates aminoxide, and sarcosinates.

Superfatting agents which may be included are saturated fatty acids having 8-24 carbon atoms. Such superfatting agents are conventional and are therefore not described further.

2 The personal cleansing bars may be produced by methods well known in the art, 25 Thus, for example, the components of the bar may be blended together, and then milled prior to plodding into bars.

The surface active agent present in the bar may be a synthetic detergent but is more preferably a soap. A typical soap bar fonnulation in accordance with the invention is as set out in Table 1 .n which all percentages are by weight.

1 0e of 1100 u. U U I. oS Soap Magnesium

C

1 o-C 1 5 alkyl sulphate Water Free fatty acid Perfume Minor ingredients TABLE 1 Broad Range 10-90% 1-40% 5-25% 2-25% ca 1% 1-5% Preferred Range 40-70% 10-25% 9-13% 4-9% ca 1% a. U

*UUU

U U *o U The invention will be further described in the following nonlimiting Examples in which all percentages are by weight unless otherwise stated.

Examples and Comparative Examples Soap bars having the compositions set out in Table 2 were prepared by standard soap making techniques.

P' -P"III L I *Soap 83/17 TABLE 2 **Soap MLS 60/40 Coconut Fatty Acid Sodium Cocoyl Isethionate 0e 0e tooo 00 :0.0.

o r *00 so so Example 1 Example 2 Example 3 Comp Ex 1 Comp Ex 2 Comp Ex 3 87% 00 0.

*c 0 Tallow/Coconut Oil 83/17 Tallow/Coconut Oil 60/40 In the above compositions, the soap and MLS each contained water such that the personal cleansing bars included 13% by weight of water.

The soaps of Table 2 were subject to Mush Immersion, Soap Lather Volume, Hardness, and Grit tests. The results are as shown in Table 3.

TABLE 3

FORMULA

Ex 1 Ex 2 Ex 3 Comp Exl Comp Ex2 Comp Ex3 MUSH HARDNESS 1WK

EXT.

R.O.W.

5 DAYS

GR

@25 0

C

1- 4.43 5.16 8.08 9.15 10.00 17.96 2.40 1.63 1.75 1.88 2.50 1.30 31.05 29.92 33.52 28.65 25.87 30.90 IT LATHER @15 0 C VOLUME 3 148.3 2 185.5 2 141.6 1 144.2 1 112.50 2 124.17

I

The results shown in Table 3 demonstrate that the soap bars of the invention Examples 1-3) produce significantly lower amounts of mush than any of the comparative products, i.e. not containing magnesium lauryl sulphate. Moreover, the lathering performance of Examples 1 and 2 was superior to all of the comparative products.

The lathering performance of the soap bar of Example 2 was particularly good. The soap bars of Example 3 and Comparative Example 1 are both based on a 60/40 tallow/coconut oil soap and it will be noted that their lathering performance is similar (that of Example .66. 3 being slightly inferior) but that the bar of Example 3 produces lower mush than that of Comparative Example 1.

So far as other properties are concerned Hardness and Grit) the soaps of the invention gave results commensurate with those of the comparative products.

The Mush Immersion, Lather Volume, Rate of Wear Harness and Grit Tests for which the results are shown in Table 3 were carried out by the following procedures.

Mush Immersion Test s* M1 Duplicate samples of the soaps to be tested were taken and each cut or planed down to a block as accurately as possible.

M2 The width and thickness of ,he block was measured to within 1 mm.

M3 The block was suspended in water at 20°C for 2 hours with the block immersed to a depth of 5 cm.

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M4 After 2 hours the block was removed from the water and allowed to drip for 1 minute.

The block was then weighed M6 All of the mush was then scraped off with a plastic spatula and the block reweighed.

M7 The amount of mush per 50 cm 2 was determined from the following equation.

Mush W x Immersed Area PPe~F~ I

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*Oe where W W1 W 2 and Immersed Area is the total immersed area of the block during step as calculated from the width, thickness, and depth of immersion (5 cm) of the block in step M3.

Lather Volume Test The test was carried out using a pair of surgeons disposable vinyl gloves which were turned inside out and rinsed to remove talc.

The following procedure was adopted.

L1 Examples of the soaps to be tested were washed for ten minutes before starting the test. The washing was effected by twisting the bars through 1800 between the hands about 20 times under running water. The bars were placed in respective plastic soap dishes.

L2 The washed bars were presented one at a time in random order to the tester.

L3 Wearing the pre-rinsed gloves, the tester dipped the first soap bar given to him/her in a bowl containing 4 litres of tap water at 400.

L4 The bar was removed from the water and twisted through 1800 between the hands for 15 times and then replaced in its soap dish.

Lather was generated by the operator rubbing the tips of his/her fingers of one hand against the palm of the other hand for times.

L6 As much lather as possible was removed from the hands by alternately gripping one hand with the other and forcing lather towards the fingertips.

L7 Accumulated lather was dislodged into a 400 ml beaker calibrated at 10 ml intervals.

L8 Steps L5-L7 were repeated.

L9 The operator then rinsed his/her hands in the first bowl.

The soap was then picked up and dipped into a second bowl containing 4 litres of water at 400C.

L11 Steps L4-L8 were repeated.

L12 The operator(s) rinsed their hands in the second bowl.

L13 Steps L10 to L12 were then repeated using a third bowl 5 S a

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I' I -L containing 4 litres of water at 40 0

C.

L14 Steps Li to L13 were repeated for each soap bar, using a different foam collection beaker for each bar.

Before lather volume was measured, the lather was stirred gently to release any large air pockets. The lather volume was then estimated using the calibration scale on the beaker.

Rate of Wear RW1 Previously weighed samples of the cleansing bars were dipped in water removed and twisted through 1800, 25 times across the face and 25 times end to end. After each set of twists the bar was dipped back in the water. This was repeated for a total of 200 twists.

RW2 The bar was allowed to dry in a soap tray for 24 hours.

RW3 Steps RW1 and RW2 were repeated every 24 hours for five days and then weighed. The Rate of Wear is expressed as the percentage weight loss at the end of the test (as compared to .original weight).

Grit G1 The top 2-3 mm of the cleansing bars was removed by washing the bar in water at approximately 40°C for about 3 minutes.

G2 The bar was washed whilst being immersed in water at 250°C for four minutes.

G3 The bar was graded on a scale of 1-5 for any course particleF, present, 1 being smooth and 5 being very course.

G4 Steps Gl-G3 were repeated but using a water temperature of 150°C in step G2.

Hardness Hardness was measured one week after manufacture of the bars using a Seta 17000-0 Universal Penetrometer in conjunction with a Seta 17000-6 Setamatic Penetrometer controller.

The hardness is the depth in mm to which the tip of the penetrometer needle penetrates into the bar after the needle is allowed to penetrate that bar for 10 seconds.

Claims (9)

1. A personal -cleansi jg bar comprising a swrface active agent (othier than (ii) below) suitable for personal washing purposes, and (ii) thle magnesiumn salt of a C 1 -C15 straight chain alkyl suilphate. 1 A bar as claimed in claim I which comprises 10-90% by weight of the surface active agent and 1A40% by weight of thle allI sulphate.

3. A bar as claimed in claim I comprising 5-25% by weight water.

4. A bar as claimied in clafim I or 2 comprising 40-70% by weight o~f the surface active agent and 10-25% by weight of die alkyl sulphate.

5. A bar as claimed in claim 4 comprising 9-13% by weight of water.

6. A bar as claimed in any one of claims 1Ito 5 wherein the alkyl chain in tUe alkyl sulphiate has 1- 13 carbon atoms. A bar as claimed i-n claim 6 wherein the alkyl sulphate, is miagnesium lauiyl sulphate. S. A bar as claimed in any one of claims I to 7 wherein the surface a~ctive agent (1) is a soap.

9. A bar as claimed in claim 8 wherein thle soap is a sodium soap. IX 4 IC F A bar as claimea in claim 8 or 9 wherein the surface active agent is a pairlnnut, oil or taflov/nut oil soap. 11, A bar as claimed in claim 10 wherein the palm (or tallow)-.nut oil ratio is in the range of 90:.10 to 10:

12. A bar as claimied ini claii 11I wherein the palm (or tallow):nut oil ratio is i the range 50:50 to 85:15.

13. A bar as clained in any one of claims 1 to 7 whierei the surfaice active agent (j) is selected from acyl iseffhionates, aikylmnethyl laurides, hycirxyalkylmethiyl taw-ides, olcyamphopolycarboxyglyiriates alkyl phosphionates wid phosphates, and di aLkyl suiphosuccinates, mono-alkyl suiphosuccinates, betaies, aLkyl ether carboxylates, sultanes, al! yl ether sulphates, glutamnates aminoxide, and sarcosinates. :14. A personal cleansing bar substantially as hereinbefo-re described in any one of .5 Examples 1-3. V.. :Dated this 11th day of July 1996 CUSSONS INTERNATIONAL LIMITED By their Patent Attorneys GRIFFITH HACK CO 0. 0.. ABSTRACT A personal cleansing bar contains a surface active agent (e.g. soap) together with the magnesium salt of a C 1 0 -C 15 straight or branched chain alkyl sulphate, most preferably magnesium lauryl sulphate. The alkyl sulphate provides a good lathering performance with low mush. *4@ S 44 S S. 55 .4 9 S 4S 4 OS* 4.. 4 S. S. S S S S

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