GB2235930A

GB2235930A - Soap composition

Info

Publication number: GB2235930A
Application number: GB8920560A
Authority: GB
Inventors: Sunil Manoharlal Sahni; Devadatta Shivaji Sanholkar
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 1989-09-12
Filing date: 1989-09-12
Publication date: 1991-03-20
Also published as: GB8920560D0; BR9004529A

Abstract

A soap composition in solid or paste form contains 35 to 90 wt% of an alkali metal soap mixture, the soap mixture comprising 0.5 to 30wt% of a soap fraction including C8, C10, C12 and C14 soaps with a weight ratio of C8 and C10 soaps to C12 and C14 soaps between 30:70 and 100:0, and 99.5 to 70wt% of a soap fraction including C16 and C18 soaps. The present soap compositions can have rather properties similar to conventional soap compositions and yet have reduced or no whole coconut oil soap content provided that the soap mixture contains at least some C8 and C10 soaps.

Description

SOAP COMPOSITION The present invention relates to a soap composition, particularly but not exclusively to a soap composition in the form of a bar.

Soap bars for personal or laundry use need ideally to satisfy a number of consumer perceived requirements. One of these requirements is the development of sufficient lather of expected quality during the washing process.

Other requirements concern the integral nature and inherent strength of the bar itself. Traditionally these requirements have been met by using a soap composition comprising a mixture of soaps of different fatty acid chain length in proportions available in natural sources.

A conventional soap mixture for use in a personal washing bar usually comprises about 5 to 40wt% coconut oil soap and 95 to 60wit% non-lauric soap such as tallow or tallow substitutes or palm oil soap.

Supplies of coconut oil, from which the coconut soap is derived, can however fluctuate in reliability of supply and additionally in price. Even when readily available coconut oil is invariably significantly more expensive than tallow or its substitutes. There is therefore a need to provide a soap composition containing a reduced amount of coconut soap in order to decrease the final cost of the composition. Any new bar should however, if desired, still be able to present the user perceived properties to the consumer similar to those to which he is already accustomed with currently available conventional bars.

According to the present invention there is provided a soap composition containing a soap mixture in which the weight ratio of C8 and C10 soaps to C12 and C14 soaps lies between 30:70 and 100:0.

Preferably the ratio in weight of C8 and C10 soaps to C12 and C14 soaps lies between 40:60 and 100:0, more preferably between 45:55 and 90:10, even more preferably between 50:50 and 80:20. Suitably the soap mixture contains between 0.5 and 30wt%, more suitably between 1.5 and 20wt% of C81 C10, C12 and C14 soaps in total. The C8 and C10 soaps are preferably provided from an appropriate fraction of coconut oil and/or palm kernel oil and/or babassu oil, in combination any contribution made from any whole coconut oil soap and/or palm kernel soap and/or babassu oil soap present.Any C12 and C14 soaps present are suitably provided by the presence of whole coconut oil soap and/or whole palm kernel oil soap and/or whole babassu oil soap, and any contribution that may be present in the natural oils fractionated to provide a source of C8 and C10 soaps.

References throughout the present specification to 10 ps", "C and C fatty acids" and "C8 and and Clo soaps", C and 8 fatty acid 10 Cl0 fraction" means C8 and C10 chain lengths present in total. Similarly C12 and C14 means C12 and/or C14. In other words it is not essential for there to be present both C8 and C10 chain lengths, or as appropriate for there to be present both C12 and C14 chain lengths. It is the total of each fraction which is important.

Whole coconut oil soap or its equivalent in known soap bars at a total level of usually between about 5 and 25wt% in the soap composition has conventionally been viewed as that part of the soap mixture which is responsible for the lather properties of the soap composition. The applicants have however found that soap compositions having lather properties similar to conventional soap compositions and yet having reduced or no whole coconut oil soap or the like content can be prepared provided that the soap mixture contains at least some C8 and C10 soaps. Although the applicants do not wish to be bound by any theory it would appear that it is these shorter chain length soaps which are primarily responsible for lather production. An overall saving in whole coconut oil and/or palm kernel oil and/or babassu oil soap can thus be made.

Coconut oil is a natural product grown in many areas of the world. The precise analysis of its fatty acid content can thus vary slightly from place to place, as well as additionally from season to season. On average however any one batch of coconut oil can be expected to include approximately 15wt% of C8 and C10 fatty acids and approximately 65wt% of C12 and C14 fatty acid, with a range of from about 14 to 18wt% C8 and C10 and from about 60 to 68 wt% C12 and C14. Equivalent figures for palm kernel oil are on average approximately 8wt% C8 and C10 fatty acids and 62wt% C12 and C14 fatty acids, ranging from about 6wt% to 10wt% C8 and C10 fatty acids and from about 61wt% to 67wt% C12 and C14 fatty acids.

The present composition containing a soap mixture having a weight ratio of C8 and C10 soaps to C12 and C14 soaps of more than 30:70 cannot therefore be provided by the use of whole conventional coconut and/or palm kernel oil sources alone. The present composition is preferably provided by the use of fractionated coconut oil/palm kernel oil/babassu oil, employing a fraction comprising primarily C8 and C10 chain lengths. For a commercially available product any one fraction will probably contain a minor proportion of chain lengths other than C8 and C10.

Nonetheless use of a fraction allows, in combination with whole coconut oil soap and/or whole palm kernel oil soap if desired, the naturally occurring C8 and C10 to C12 and C14 ratio to be altered.

If desired the present soap mixture can contain coconut oil soap fraction in the absence of whole coconut oil soap and/or whole palm kernel oil soap. Suitably however coconut oil fraction soap is employed in combination with whole coconut oil soap. When calculating the final content of actual Cg, C10, C12 and C14 soaps in the end product the contribution of C8 and C10 from the whole coconut oil or the like soap source and the contribution of any residual C12 and C14 in the coconut oil fraction must of course not be overlooked.

For a C8 and C10 soap component comprising at least 85wt% C8 and C10, for example as obtainable from coconut oil, preferred component ranges are 0.5 to 7wt% C8/C10 coconut oil fraction and 0 to 25wt% whole coconut oil or the like soap, each with respect to the total soap ixture present.

The remainder of the soap mixture is suitably composed of soaps providing primarily C16 and C18 soaps.

Appropriate examples of such soaps are those derived from tallow, hydrogenated tallow, hydrogenated rice bran oil, palm oil, hydrogenated palm oil, hydrogenated linseed oil and hydrogenated soya bean oil. The proportion of such soap sources present in the final soap composition will depend on the quality desired in the end product and will suitably range from 99.5 to 70wt% of the soap.mixture.

All of the soaps employed in the present compositions are preferably sodium soaps. If desired however other alkali metals, ammonia and/or alkyl and/or alkanol ammonia substituted soaps can be employed.

The overall soap mixture part of the soap composition will suitably comprise 35 to 90wits of the soap composition. In a soap bar moisture will probably comprise at least lOwt% of the composition suitably between 11 and 14wt%.

The invention also provides a composition for fabric washing containing i) 25 to 60% by weight of soap and ii) 25 to 558 by weight of solid structurant including soluble alkaline silicates/phosphates. The bar also contains water preferably 12% to 35% and other optional ingredients such as perfume, colour and preservative.

The soap composition can contain other ingredients conventionally present in bars and the like. Examples of such ingredients are builders, structurants, fillers, polymers, dyes, perfumes, pearlescents, anti-oxidants and preservatives. Kaolin is a preferred additional ingredient and can suitably be present in an amount between 10 and 30wt% with respect to the total composition.

The composition of the present invention may also contain water soluble alkaline silicate and phosphates.

The composition may contain structurants insoluble in water, such as (i) silica, sheet or framework crystalline silicate, with or without ion exchange capacity, such as for example, clay, talc, zeolite, kaolin, (ii) alkaline earth carbonates such as dolomite and calcite,. magnesite, etc. and (iii) water insoluble polysaccharides such as starch or cellulose and (iv) mixtures of any of these.

The present composition can be in solid, paste or liquid form. The solid form is preferably in the form of bars, but could alternatively be provided in powder, granule or flake form.

The present composition is suitably made by conventional soap processing techniques comprising crutching, milling and extrusion into the desired form.

Preferably a source of ready formed C8 and C10 soaps is added prior to the milling.

The C8/C10 soap fraction could be formed by hydrolysis of the methyl ester of C8/C10 fatty acids on melting of the mixture at the neat soap stage or such at the saponification stage on addition to the bulk of the soap mixture at the neat soap phase.

Embodiments of the present invention will now be described by way of example only with reference to the following examples, Examples 1 and 2 Soap chips comprising a mixture of 3.4wt% coconut oil soap and 96.6wt% hardened rice bran oil soap were admixed in a Sigma mixer with soap derived from a fraction of coconut oil comprising 52.3wt% C8 fatty acid, 36.3wt% C10 fatty acid and 11.4wt% C12 fatty acid. Different amounts of soap made from the fractionated coconut oil were added in Examples 1 and 2 respectively. The mixed mass was milled and extruded into billets. The resulting billets were assessed for lather.Comparative tests were performed on similarly prepared billets containing ll.lwt% coconut oil soap and 88.9wt% hardened rice bran oil soap, but with no added soap made from fractionated coconut oil.

The formulations of the soap compositions employed in terms of coconut oil derived soap and the correlating C8, C10, C12 and C14 content are given in Table I below. Each of the present examples was assessed for subjective lather.

Table I Example 1 2 Comparative Whole coconut 3.4 3.4 11.1 (wt% of the soap oil soap content chips) Fractionated coconut 3.3 2 0 (wt% with respect oil soap content to base soap chips) C8 and C10 soaps 3.4 2.3 1.7 (wt% with present respect to total soap mixture) C12 and C14 soaps 2.5 2.4 7.2 (wt% with present respect to total soap mixture) Ratio of C8 and C10: 58:42 49:51 19:81 C12 and C14 Lather subjective 40.0 44.0 31.8 (ml) The subjective lather test is an internal standard test of the applicants, designed to provide quantitative comparison between different bars in a standarised manner within each comparison. After a standard washing procedure using 240FH water, the volume of lather produced was measured.

The present examples containing a reduced amount of whole coconut oil soap in combination with fractionated coconut oil soap were deemed to have lather properties significantly improved compared to a conventional soap bar formulation containing ll.lwtZ whole coconut oil soap.

The addition of C8 and C10 fatty acid soaps have synergistically improved lather performance.

Example 3 Structured toilet bars were prepared by the process described under Examples 1 and 2 above employing a mixture of 80wt% soap base and 2Owt% kaolin. In a toilet bar embodying the present invention the soap base mixture comprised 97.6wit% hardened rice bran oil soap and 2.4wt% coconut oil soap, to which was post dosed 2.6wt%, measured with respect to the initial soap base mixture, of the coconut oil C8/C10 fraction described under Example 1 above. A comparative structured soap bar was prepared in which the soap mixture consisted only of 88.2wt% hardened rice bran oil soap and 11.8wt% whole coconut oil soap.

The make-up of each soap bar in terms of its coconut oil derived soap and its correlating C8, C10, C12 and C14 soap content is given in Table II below. Each of the present examples was assessed for subjective lather.

Table III Example 3 Comparative Whole coconut oil 2.4 11.8 (wt% of the soap content soap base) Fractionated coconut 2.6 0 (wt% with oil soap content respect to the soap base) C8 and C10 soaps present 2.6 1.8 (wt% of total soap mixture) C12 and C14 soaps present 1.8 7.7 (wt% of total soap mixture) Ratio of C8 and C10 59:41 19:81 and and C14 Lather subjective (ml) 32.3 35.8 In use the lather properties of the bar embodying the present invention and containing a reduced amount of a whole coconut oil soap in combination with fractionated coconut oil soap were fpund to be comparable to the comparative example containing 11.8wt% of whole coconut oil soap.

Example 4 The procedure described under Examples 1 and 2 was followed employing a soap base comprising 88.2wt% hardened rice bran oil soap and 11.8wt% whole coconut oil soap.

This soap base was formed into billets to provide the comparative examples. In a billet embodying the present invention the same procedure was followed and 5.3wt%, measured with respect to the soap base, of the above described C8/C10 fraction of coconut oil soap was post-dosed prior to milling and extrusion.

The composition of the resulting billets in terms of their coconut oil derived soaps is given in Table III below together with their subjective lather assessment.

Table III Example 4 Comparative Whole coconut oil 11.8 11.8 (wt% of the soap content soap base) Fractionated coconut 5.3 0 (wt% with oil soap content respect to the soap base) C8 and C10 soaps present 6.1 1.8 (wt% of total soap mixture) C12 and C14 soaps present 7.9 7.7 (wt% of total soap mixture) Ratio of C8 and C10 44:56 19:81 C12 and C14 Lather subjective (ml) 45 37.5 The billet having added C8/C10 coconut oil soap fraction had improved lather properties.

Example 5 Toilet soap billets were prepared from a soap composition which contained C8 and C10 soaps which had been formed by in situ hydrolysis by adding the methyl esters prepared from the above described C8/C10 coconut oil fraction to the bulk of the soap base at the neat soap stage. The neat soap employed was wholly derived from hardened rice bran oil. The lather characteristics of the billets were assessed and compared to those of a conventional toilet soap bar containing hardened rice bran oil soap and 5wt% whole coconut oil soap.

The compositions of the billets and the lather results are given in Table IV below.

Table IV Example 6 Comparative Total fatty matter 35 35 (wt%) Alkaline silicate 14 14 (wt% of composition) C8/C10 methyl ester 1 0 (wt% of final composition) C8 and C10 content 1.7 0.8 (wt% of total soap mixture) C12 and C14 content 0.2 3.3 (wt% of total soap mixture) Ratio of C8 and C10: 89:11 20:80 C12 and C14 Lather in 240FH 17 15.8 (ml) water The lather properties of the two examples were comparable notwithstanding the fact that the example embodying the present invention contained no whole coconut oil soap.

Example 6 Laundry soap billets were prepared from a soap composition which contained C8 and C10 soaps which had been formed by in situ hydrolysis by adding methyl ester prepared from the above described C8/C10 coconut oil fraction to the bulk of the soap at the neat soap stage.

The neat soap employed was wholly derived from hardened rice bran oil. 15wt% kaolin was added to neat soap and the mixture was flash dried to 32wt% moisture and plodded into billets. The lather characteristics of the billets were assessed and compared to those of a conventional laundry soap bar.

The composition of the billets and lather results are given in Table V below: Table V Example 6 Comparative Total fatty matter 35 35 (wE% of composition) Alkaline silicate 14 14 (wt% of (composition) Kaolin 15 15 (wt% of composition) Moisture 32 32 (wt% of composition) Whole coconut oil soap 0 10 (wt% of total fatty matter) C8/C10 methyl ester added 1.5 0 (wt% of total and in situ saponified composition) C8/C10 soap content 3.8 1.5 (wt% of total soap mixture) C12/Cl4 soap content 0.49 6.5 (wt% of total soap mixture) Ratio of C8/C10 soap: 89:11 19:81 C12/C14 soap Lather in 240FH 83 93 (ml) soil system A test cloth dippied in 240FH water and wrung was soiled after spreading 240FH water on the cloth, the soiled cloth was rubbed with the laundry bar in identical manner in both instances and the rubbed fabric was squeezed, lather and liquor were collected and lather volume measured.

Claims

1. A soap composition containing a soap mixture in which the weight ratio of C8 and C10 soaps to C12 and C14 soaps lies between 30:70 and 100:0.

2. A soap composition according to claim 1 wherein the soap mixture has a weight ratio of C8 and C10 soaps to C12 10 12 and C14 soaps lying between 40:60 and 100:0.

3. A soap composition according to claim 2 wherein the soap mixture has a weight ratio of C and C10 soaps to 12 soap 8 10 soaps to C and C14 soaps lying between 40:60 and 90:10.

4. A soap composition according to any one of the preceding claims wherein the soap mixture contains between 0.5 and 30wt% of C8, C10, C12 and C14 soaps in total.

5. A soap composition according to any one of the preceding claims wherein the soap mixture contains in total 0 to 25wt% whole coconut oil soap and/or whole palm kernel oil soap and/or babassu oil soap and 0.5 to 7wt% C8 and C10 soaps obtained from fractionated coconut oil and/or fractionated palm kernel oil and/or fractionated babassu oil.

6. A soap composition according to any one of the preceding claims wherein the soap mixture contains C16 and C18 soaps.

7. A soap composition according to claim 6 wherein the soap mixture contains between 99.5 and 70wt% of C16 and C18 soaps.

8. A soap composition according to claim 7 wherein the C16 and C18 soaps are present in the form of tallow, hydrogenated tallow, hydrogenated rice bran oil, hydrogenated linseed oil, hydrogenated palm oil and/or hydrogenated soya bean oil soaps.

9. A soap composition according to any one of. the preceding claims additionally containing 10 to 30wt% kaolin.

10. A soap composition according to any one of the preceding claims in the form of a bar.

11. A method for making a soap composition containing a soap mixture in which the ratio of C8 and C10 soaps to C12 and C14 soaps lies between 30:70 and 100:0 in which a soap comprised primarily of C8 and C10 soaps is admixed with the remainder of the soap mixture.