EP1141228B1

EP1141228B1 - Improved detergent bar composition

Info

Publication number: EP1141228B1
Application number: EP99973608A
Authority: EP
Inventors: Atul Hindustan Lever Ltd BHATIA; Ravi Hindustan Lever Ltd HARIKIRAN; Vineet Hindustan Lever Ltd MITAL; Devarakonda Hindustan Lever Ltd SAIKRISHNA
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 1999-01-11
Filing date: 1999-11-03
Publication date: 2004-03-03
Anticipated expiration: 2019-11-03
Also published as: ZA200104733B; ID29445A; CN1332794A; BR9916859B1; WO2000042160A1; JP4537586B2; DE69915353D1; AU1158700A; CA2359135A1; AU762285B2; DE69915353T2; JP2002534598A; CN1179031C; BR9916859A; CA2359135C; ATE260969T1; EP1141228A1

Abstract

A soap bar composition comprising 40-85% soap and 0.1-10% of a branched chain nonionic fatty acid ethoxylate surfactant. Preferably the fatty acid ethoxylate surfactant has an EO number no greater than 7.

Description

The invention relates to a detergent composition with superior sensory and in-use properties.

Soaps have long been manufactured from fats by conversion of triglyceride components of fats into fatty acid salts, followed by the formation of these 'soaps' into various product forms such as bars, liquids, gels etc. However, fatty acid soaps have various shortcomings such as depression of lather in hard water, formation of lime soap curd, cracking and embrittlement of the bars, poor sensory properties, harshness on the skin and other problems.

There have been several approaches to solve these problems. GB 931,731 discloses the use of non-ionic surfactants such as ethoxylated and propoxylated alkanol amides in soap bars to prevent lime soap formation during use in hard water.

Fatty alcohol ethoxylates in soap bars (such as e.g. WO9317088 or EP363215) have been known to reduce lime soap formation, and hence prevents soap residue on skin. This results in improved mildness and product properties such as lathering, reduced mush etc.

Straight or branched fatty acid ethoxylates (such as in e.g. JP59179599, JP05117138 or JP07179322) are known to impart superior detergency against heavy chains, make-up and are known to generate good foam and have conditioning effect on hair and skin. These disclose liquid formulations containing straight or branched fatty acid ethoxylates with a degree of ethoxylation greater than 7 and incorporation levels of 10-60% by weight.

JP 05-262639A discloses a detergent composition for reducing eye-stimulating tendency comprising: (a) a higher fatty acid soap(s) in an amount of from 5-50 wt.%; and (b) 0.1 to 15 wt.% of a compound of formula X₁O(CH₂CH₂O)_nX₂ (A) where X₁ and X₂ are each H or -COR and where R is 7-17C, opt. branched (un)satd. hydrocarbon and n = 3 - 2000.

EP-A-0311343 describes a toilet bar composition comprising: (a) from about 45% to about 90% by weight of soluble alkali metal soap of C₈-C₂₄ fatty acids; (b) from 0.5% to about 45% of an ethoxylated nonionic surfactant having an HLB in the range of from about 12 to about 19.5; and (c) from about 0.01% to about 5% of a water-soluble polymer.

US 4,290,904 describes a transparent low alkalinity bar soap comprising a tetrakis (hydroxyalkyl) ethylene diamine, a sodium soap prepared by saponification of fatty oil, a polyhydric alcohol to ensure transparency and a fatty acid superfatting agent.

US 5,300,694 discloses novel substituted alkoxylated phenol compounds for use in cosmetic stick formulations.

Conventionally perfumes are incorporated into soap formulations to mask the soap base odour and provide a sensory attribute. The perfume impact of soaps reduces on storage, and as a result only a part of the initial perfume added at the time of manufacture is perceived by the end user.

We have now found that surprisingly using certain branched chain nonionic surfactants at very low levels in a soap formulation gives improved perfume impact even after prolonged storage of the formulation under various environmental conditions. It also gives enhanced benefit with respect to performance, and sensory properties even under hard water conditions.

It is the basic objective of the present invention to provide a detergent composition with enhanced perfume impact on storage along with improved sensory and in-use properties.

Another object of the present invention is to provide detergent composition with superior sensory and in-use properties which would be simple to manufacture, and will be cost-effective.

According to the present invention there is provided a detergent composition comprising of:

i. 40 to 85% soap

ii 0.1-10% branched chain fatty acid ethoxylate with EO not greater than 7 and

iii 0.1 to 3% pertume

iv. other conventional ingredients.

In the above detergent composition of the invention soap varies from 40 to 85% by weight and it essentially comprises of C₈-C₁₄ fatty acids soaps in an amount of up to 50% by weight, and preferably up to 25% by weight. The balance soap is selected from palmitic, stearic, oleic and linoleic fatty acids such that the Iodine Value of the final soap composition varies from 0-60, preferably in the range of 30-50.

Non-ionic surfactants used in the composition of the invention is preferably selected from branched chain fatty acid ethoxylates with a general formula RCOO(CH₂CH₂O)_nH, where n varies from 1 to 7. The preferred fatty acid is isostearic acid, and the preferred level of ethoxylation in the range 3-5. The non-ionic surfactant is incorporated in the final soap composition at 0.1-10% by weight and preferably from 1-5% by weight.

Optional ingredients such as polycarboxylic acid, alkylsulphate ethoxylates, super fatting agent such as fatty acids, and moisturising agents such as glycerine to improve the performance may be incorporated. Other conventional ingredients for e.g. fillers, perfumes, opacifiers, preservatives, antimicrobial agents, as required are added to the formulation.

Any polycarboxylic acids in the composition are generally aliphatic and branched or straight chained. The polycarboxylic acid is preferably a C₂-C₁₂ dicarboxylic acid and more preferably a C₂ to C₈ dicarboxylic acid.

The superfatting may be provided in the composition of the invention either by the addition of a superfatting agent such as a triglyceride of fatty acids of C₆-C₁₈ carbon atoms or by the addition of fatty acids of C₆-C₁₈ type. Superfatting can also be achieved by addition of polycarboxylic acids or mineral acids to soap.

Fillers may be incorporated at 0-40% and selected from hydrated magnesium silicate, hydrated aluminium silicate or any other suitable material.

Perfumes can be used in formulating the product at a level of from 0.1 to 3% of the composition.

The invention will now be described with reference to the following non-limiting examples.

EXAMPLES:

Different soap compositions under Examples 1 and 2 (Controls) and Examples 3 and 4 (in accordance with the invention) detailed in Table 1 were prepared as toilet soap bars as described hereunder:

Composition (% wt.)	Example 1	Example 2	Example 3	Example 4
Soap	55.0	55.0	55.0	55.0
Isostearic acid	-	2.0	-	-
Isostearic acid EO 3	-	-	2.0	-
Isostearic acid EO 5	-	-	-	2.0
Fillers	29.0	29.0	29.0	29.0
Perfume	1.5	1.5	1.5	1.5
Minor ingredients	2.0	2.0	2.0	2.0
to 100% with water

Method of manufacture followed:

480 kg of neat soap was taken in the holding tank and spray dried into noodles of moisture content of about 14%, which was then taken in a conventional sigma mixer. The other specific ingredients mentioned for the different Examples were added during mixing to obtain the specific formulation. Other minor ingredients and water was added and mixed, milled and plodded into bars and stamped subsequently.

Lather/Rate of wear index:

Lather of the soap bar was determined both in soft water (4 deg. French hardness) and hard water (24 deg. French hardness) by a panel of five members. The soap bar was rotated in the palm 20 times approx. with a little water and the lather generated was poured into a measuring jar to determine the quantity in millilitres. An average of 15 such measurements were reported as the final value of lather. Rate of wear was determined by a panel of five members who used the personal wash bar with 10 rubs a day for four days. At the end of four days, each tablet was washed free of the mush and was weighed to determine the final weight and the difference between the initial and final weights is reported as % wear.

Lather/rate of wear (ROW) index which is determined using the above mentioned information on lather volume and rate of wear is an indicator of the user value perception, wherein a lower number would mean that the lather generated per unit rate of wear is low, and the consumer has to use more quantity of soap per bath. The data presented in Table 2 shows that this lather/ROW index has improved after incorporation of isostearic acid with 3 or 5 EO and is superior to the Control and that with unbranched isostearic acid.

Lather/Rate of wear	Example 1	Example 2	Example 3	Example 4
Soft water	2940	3556	4000	3684
Hard water	3046	3545	3891	3623

Improvement in in-use properties:

In-use properties such as lather volume, rate of wear and sensory properties such as after wash feel, in-use feel and lather characteristics and perfume impact on storage were analyzed using control bars, and those according to the invention, which contained 2% by weight of branched isostearic acid with 3EO (Table 3).

Composition (% wt.)	Example 5	Example 6
Soap	82.0	80.0
Isostearic acid 3EO	0.0	2.0
Perfume	1.5	1.5
Minor ingredients	2.0	2.0
Water	To 100	To 100

Rate of wear:

Rate of wear was determined by a panel of five members who used the personal wash bar with 10 rubs a day for four days. At the end of four days, each tablet was washed free of the mush, and was weighed to determine the final weight and the difference between the initial and final weights is reported as % wear.

Lather:

Lather of the soap bar was determined both in soft water (4 deg. French hardness) and hard water (24 deg. French hardness) by a panel of five members. The soap bar was rotated in the palm 20 times approx. with a little water, and the lather generated was poured into a measuring jar to determine the quantity in millilitres. An average of 15 such measurements were reported as the final value of lather.

Feel:

The feel assessment was carried out by an internal panel to evaluate the lather, in-use feel and post wash feel qualitatively, and expressed quantitatively on a scale of 1 - 5. The soap bar was wetted and applied on the forearm by the panelist, and observed for performance with respect to the above mentioned parameters.

Perfume impact:

Perfume impact was assessed by a panel of expert perfumers on a scale of 1-10. This was done initially and after a period of storage up to 24 weeks.

Attribute	Example 5	Example 6
Tablet wear (g)	20	16
% wear	27%	16%
Lather volume (ml)	396	405
Mush volume	1.83	1.25
Feel: Lather creaminess	3.42	3.71
In-use feel:
Draggy-slippery	3.3	3.5
Post wash feel:
Slimy-squeaky	3.35	3.29
Dry-Moist	3.25	3.36
Perfume:
Initial Impact	7.0	7.0
Impact after 24 weeks	4.5	5.0

The data presented in Table 4 shows that the formulation according to the invention shows that the % wear and mush volume is reduced whereas the lather volume is increased and the lather generated is creamier and that the in-use and after wash feel is superior. The impact of the perfume gradually reduces due to storage but in the formulation prepared according to the invention even after storage the perfume impact is maintained significantly superior.

Claims

A soap bar composition comprising 40-85% by weight soap, 0.1 - 10% by weight of a branched chain nonionic fatty acid ethoxylate surfactant and 0.1 to 3% by weight of perfume, characterised in that the branched chain fatty acid ethoxylate surfactant has an EO number not greater than 7.
A bar composition according to claim 1 wherein the soap comprises C₈-C₁₄ fatty acids in an amount of up to 50%, more preferably up to 25% by weight.
A bar composition according to claim 1 or 2 wherein the EO number is in the range 3-5.
A bar composition according to any one of the preceding claims additionally comprising a C₂-C₁₂ dicarboxylic acid.
A bar composition according to any one of the preceding claims, wherein the branched chain nonionic surfactant is present at a level of 1 - 5% by weight.