ZA200606914B

ZA200606914B - Improved detergent bar

Info

Publication number: ZA200606914B
Application number: ZA200606914A
Authority: ZA
Inventors: Gangopadhyay Manish; Joshi Alok Bhagwat; Prabhudesai Vaishal Ramchandra; Shah Nimish Harshadrai
Original assignee: Unilever Plc
Priority date: 2004-02-20
Filing date: 2005-02-10
Publication date: 2007-11-28
Also published as: AR047809A1; CN100471941C; BRPI0507214A; CN1942574A; WO2005080541A1

Description

IMPROVED DETERGENT BAR

The present invention relates to non-granular solid cleaning cermposition. In particular, it relates to soap bars with lower levels of total fatty matter that maintain their integrity and shape and remaining microbially stable under varying storage and transport condition. The composition also provides for the desired user properties such as lather, cleaning and low mush during use. :

There have been many solid cleaning compositions comprising soap known in the art. It is believed that generally the cleaning action in soap bars is provided for by the soluble soaps i.e salts of fatty acids, which are soluble in water, while the insoluble soaps provide the integrity and structure the shape of the soap bar. There have been several attempts made to provide alternative, less expensive materials for structuring the shape of the bars.

US 5194172 (P&G, 1993) describes a process for preparing an aerated freezer soap bar which composition comprises 25 % to 70 % of alkali metal fatty acid soap, 5 to 35 wt % sucrose, 3 to 20 wt% of a hydrophobic material selected from waxes, free fatty acids and fatty alcohols wherein the hydrophobic material comprises at least 3 wt% waxes and 10 % to 30 % water, and the composition does not contain effective amount of water-soluble organic non-soap synthetic detergent.

US 4518517 (Colgate, 1985) describes a cleaning composition which may be liquid or a solid bar which essentially comprises an anionic detergent active which may be a synthetic detergent or a tallow or coconut fatty acid soap, and is characterized by inclusion of at least one carbohydrate selected from glucose, mannose and oligomers thereof at 2.5 to 10 wt% which is effective tc reduce the odour causing bacterial population of the body without the use of antimicrobials.

US 3630925 (Arrowhead, 1971) describes deodourant and germicidal bodies especially in the form of tablets or blocks for cleaning toilets and urinals, which comprise 60 % to 75 % sugar, 20 % to 25 % water soluble soap and 2 % to 5 % water dispersible germicidal agent. The germicidal agents described include o-phenylphenol and 2,2'~ methylenebis- 3,4,6-trichlorophenol (which is also known as bis-(3,5,6- trichloro-2 hydroxyphenol) or 2,2'-dihydroxy-3,5,6,3',5',6'- hexachlorodiphenylmethane or hexacblorophene).

Other germicidal agents which are described include quaternary ammonium salts such ‘as p-diisobutyl phenoxy = ethoxy ethyl dimethyl benzyl ammonium chloride monohydrate, or benzalkonium chloride, or 2,4,5 trichlorophenol, or benzyl-o-chlorophenol.

The present inventors have found that soap bars comprising sugars like mono- or disaccharides tend to have poor stability on storage over extended time and/or under adverse conditions, and are especially prone to attack by fungi.

They also tend to have poor structural stability exhibiting problems like cracking of the bar. Also desirable user properties such as lather tend to be effected.

The present inventors have now found that a solid cleaning composition comprising.soap at specific low levels of total fatty matter can be structured with mono- or disaccharides, and tend to have excellent storage stability against growth of microorganisms like fungi and provide the desired user . properties like low mush, high lather etc. by incorporation of a stabilising agent in small amounts, preferably by further addition of free fatty acids in specific amounts.

Further, it has surprisingly been found that a small amount of a known hardening agent like alkali metal carbonate or bicarbonate provides for significant improvement in structural integrity of the bar e.g. in terms of reduced cracking of the bar under storage and use conditions. 15°

It is thus an object of the invention to be able to provide for a non-granular solid cleaning composition with reduced levels of total fatty matter which is stable against microbial contamination, especially fungi, undér varied storage, transport and usage conditicns.

It is a further object of the invention to be able to provide for a non-granular solid cleaning composition with reduced levels of total fatty matter which in addition to being stable against microbial contamination, especially fungi under varied storage, transport and usage conditions, provides for the desired levels of cleaning and user properties such as low mush and enhanced lather, and also maintains structural integrity under all these conditions.

It is yet another object of the present invention which in addition to the above objects can be prepared in a cost- effective manner.

According to a first aspect of the invention, there is provided a non-granular solid cleaning composition comprising: (a) 50 % to 70 % salt of fatty acid; (b) 1 % to 15 % of a mono- or disaccharide; and (c) 0.02 % to 2 % of a stabilising agent.

According to a preferred aspect of the invention, there is provided a non-granular solid cleaning composition comprising: . (a) 50 % to 70 % salt of fatty acid; + (b) 1 % to 15 % of a mono- or disaccharide; (c) 0.02 % to 2 % of a stabilising agent; and (d) 0.2 % to 6 % of free fatty acid of carbon chain length 8 to 22. TT DE

According to a further preferred aspect of the invention, there is provided a non-granular solid cleaning composition comprising: (a) 50 % to 70 % salt of fatty acid; (b) 1 % to 15 % of a mono- or disaccharide; (c) 0.02 % to 2 % of a stabilising agent; (d) 0.2 % to 6 % of free fatty acid of carbon chain length 8 to 22; and (e) 0.1 % to 2 % alkali metal carbonate or bicarbonate.

Cs

It is particularly preferred that the stabilising agent is formaldehyde, benzoic acid or sodium benzoate.

The present invention provides for a cleaning composition that comprises salt of fatty acid, a mono- or disaccharide and a stabilising agent.

The term salt ot tatty acid is also known as soap which denotes salts of carboxylic fatty acids such as for example sodium, zinc, potassium, magnesium, alkyl ammonium and aluminium salts of fatty acids. The soap may be derived from any of the triglycerides conventionally used in soap manufacture ~- consequently the carboxylate anions in the soap may contain from typically 8 to 22 carbon atoms.

The soap may be obtained by saponifying a fat and/or a fatty acid. The fats or oils generally used in soap manufacture may be such as tallow, tallow stearines, palm oil, palm stearines, soya bean oil, fish oil, castoroil, rice bran oil, sunflower oil, coconut oil, babassu oil, palm kernel oil, and others. In the above process the fatty acids are derived from oils/fats selected from coconut, rice bran, groundnut, tallow, palm, palm kernel, cotton seed, soyabean, castor etc. The fatty acid soaps can also be synthetically prepared (e.g. by the oxidation of petroleum, or by the hydrogenation of carbon monoxide by the Fischer-Tropsch process). Resin acids, such as those present in tall oil, may be used. Naphthenic acids are also suitable.

Tallow fatty acids can be derived from various animal sources and generally comprise about 1 % to 8 % myristic

-— 6 ~— acid, about 21 % to 32 % palmitic acid, about 14 % to 31 % stearic acid, about 0 to 4 % palmitoleic acid, about 36 % to 50 % oleic acid and about 0 to 5 % linoleic acid. A typical distribution is 2.5 % myristic acid, 29 % palmitic acid, 23 &% stearic acid, 2 % palmitoleic acid, 41.5 % oleic acid, and 3 % lincleic acid. Other similar mixtures, such as those from palm oil and those derived from various animal tallow and lard are also included.

Coconut oil refers to fatty acid mixtures having an approximate carbon chain length distribution of 8 % Cg, 7 %

Cio, 48 % C12, 17 % C14, 8 % C16, 2 % C18, 7 % oleic and 2% linoleic acids (the first six fatty acids listed being saturated). Other sources having similar carbon chain length distributions, such as palm kernel oil and babassu kernel oil, are included within the term coconut oil.

A typical fatty acid blend consisted of 5 % to 30 & coconut—- : fatty acids, and 70 % to 95 % fatty acids ex-hardened rice 20° bran oil. Fatty acids derived from other suitable oils/fats such as groundnut, soybean, tallow, palm, palm kernel, etc. may also be used in other desired proportions.

The soap in the present invention is present in an amount of 50 % to 70 %, preferably from 55 % to 68 % and more preferably from 58 % to 68 % by weight of the composition.

It is preferable that the iodine value of the fat charge be in the range of 30 to 50, more preferably 34 to 46, most preferably 38 to 42.

It is preferable that the moisture content of the composition is in the range of 9 % to 20 %, more preferably in the range of 12 % to 16 %.

Any mono~ or disaccharides, or a combination of two or more are present in the composition of the invention. The saccharides are preferably chosen from ylucose, sucrose, mannose, or fructose. It is particularly preferred that the saccharide used is glucose or sucrose.

The monc- or disaccharide is typically present in an amount of 1 % to 15 % by weight of the composition, more preferably from 6 % to 12 % by weight of the composition.

The stabilising agent is preferably chosen from the class of fungicides. Preferred stabilising agents include formaldehyde, benzoic acid and salts thereof, methyl or “ethyl paraben. oT :

The stabilising agent is present in an amount of 0.02 % to 2 % by weight of the composition, more preferably in an amount of 0.05 % to 1 % by weight of the composition. The stabilising agent is generally added in an amount which is sufficient to inhibit the growth of microorganisms e.g fungii on the composition, and at the same time is not high such that it produces undesired characteristics such as e.g off-odours. For example, a stabilising agent like formaldehyde is available as a solution in water e.g at 30 % to 40 % concentration, and the solution may be added in an amount of 0.1 % to 0.2 % by weight of the composition.

Free fatty acids are preferably included in the composition of the invention. The free fatty acids may have carbon chain length in the range of 8 to 18. The free fatty acid is preferably “lauric” fat. The coconut and palm kernel fats 3 (together known as the lauric fats) are particularly rich in the C1g-C14 saturated fatty acids, particularly fatty acid residues derived from lauric acid itself. For convenience these fats, containing saturated, relatively short chain fatty acids, are generally referred to as the ‘lauric’ fats.

This definition includes the coconut, palm kernel, babassu or macauba oils. The free fatty acids are preferably present in an amount of 0.5 % to 6 %, more preferably 0.5 % to 2 % by weight of the composition.

The composition of the invention preferably comprises an alkali metal carbonate or bicarbonate. The preferred compound is sodium carbonate. The alkali metal carbonate or bicarbonate is preferably present in an amount of 0.1 % to 2 $ by weight of the composition, more preferably in an amount of 0.2 % to 1.5 % by weight of the composition.

The invention is carried out in any mixer conventionally used in soap/detergent manufacture, and is preferably a high shear kueading mixer. Preferred mixers include ploughshare mixer, mixers with kneading members of sigma type, multi- wiping overlap, single curve or double arm. The double arm © kneading mixers can be of overlapping or tangential in design. Alternatively, the invention can be carried out in a helical screw agitator vessel or multi-head dosing pump/high shear mixer and spray drier combinations as in conventional processing.

- 9 ~

The invention will now be demonstrated with the help of typical non-limiting examples of the process according to the invention, as also with the help of comparative results of the composition prepared by the present invention and beyond the invention.

EXAMPLES

Comparative Example A

A base soap bar of 72 TFM was made free of grit by milling in a roll mill, and then plodded and stamped to get bars of desired shape.

Comparative Example B

A bar was prepared by mixing a base soap of 65 TFM along with sugar and sorbitol as per the composition given in "Table 1. The mixing was done in a sigma mixer for sufficient time until there was no gritty feel. The mass was then milled in a roll mill, and then plodded and stamped ‘to obtain bars of desired shape.

Example 1

A bar as per comparative Example B was prepared except that an additional 0.2 $% formaldehyde was added during mixing.

Table 1

Components Comparative | Comparative Example 1

Example A Example B

Er CE FC FT

Sorbitel [= [5 [5

Formaldehyde |- - lo.2

Water To 100 To 10C To 100

The samples of the products prepared were subjected to a stability test as per the procedure given below.

Stability Test :

Fungal spores of A. versicolor, A. niger and an isolate from a contaminated soap wrapper (Rexona) were used as a mixed challenge inoculum at a concentration of 10” per sg. cm. surface. The five samples challenged in this manner were incubated at 100 % RH, 85 % RH and ambient. The results after a month's incubation are as given in Table 2.

Table 2

Test Comparative | Comparative | Example 1 conditions Example A Example B 55% Ri

ETT CE EE

+/- denotes no apparent growth or very slight indication. + denotes spore germination/spore swelling ++ denotes vegetative growth with little or no sporulation

The data in Table 2 indicates that bars prepared as per the invention (Example 1) are stable and comparable to control bar (Comparative Example A), whilst the bar containing sugar with no formaldehyde (Comparative Example B) displays poor stability.

User Properties

Bars were prepared as per the compositions given in Table 3.

Table 3

Components | Comparative | Comparative | Comparative | Comparative

Example A Example C Example D | Example E [TEY

Sugar ~~ [- © fio {10 T1060

Lauric 2 2

Acid

Sodium

Carbonate

To 100 To 100

The above samples were tested for user properties like mush volume, cracking, and lather. The test procedures used were as follows.

Mush Volume

The mush volume is measured on a bar composition that has been used. The depth of the mush is measured in millimeters, and the area of the bar underface affected by the mush formation is measured. These measurements are made each day over a course of 4 days of use. The mush volume is obtained by summing the four daily ratings.

WO

2005/080541 PCT/EP2005/001453

Cracking

The bars were evaluated for cracking on a 14 point scale wih a score of zero denoting no cracking and 14 denoting very severe cracking, over four days of use of the product.

Lather volume

The bars were lathered with a fixed amount of water of fixed hardness (4 FH) by trained operators, using their hands with gloves. The procedure involved rubbing the bar wetted with water by twisting the bar 15 times in the hands, followed by lathering up the composition on the gloved hand with a specific number of rubs (20 rubs). The lather generated is carefully transferred to a graduated cylinder and the lather volume measured.

The samples were also subjected to the stability test as described earlier.

The tests with the various samples gave the following results, tabulated in Table 4.

Tahle 4

Components Comparative Comparative Comparative Comparative

Example A Example C Example D Example E volume

Cracking Jo Jo 3.9 lo ther am leis [ss [a5

Example 2

A sample as per Comparative Example E was prepared, except that it further contained 0.2 % formaldehyde. This bar was also assessed for the in-use and stability test. The bar as : per Example 2 gave as good in-use property as Comparative

Example E. Additionally, the bar was highly stable on storage to fungal growth.

Comparative Examples F, G and Examples 3,4

Further samples of detergent bars were prepared as per the compositions given in Table 5.

The bars prepared were subjected to the stability test as conducted for Example 1, and the summary of the observations is also summarized in Table 5. “Table 5

Components Comparative Comparative Example 3 | Example 4

Example F Example G

Tm e117 eso [eso es

Sugar 60 [5.0 [5.0 ~~ ls.0o

Sorbitol 4.0 Zo [40 (40

Homeic Aola[15 3.5 [1.5 Joo

Sodium 10.9

Carbonate

Tal. 4.0 [an 14.0 4.0

Other minor | 2.8 3.3 3.3 2.8 ingredients omnaidenyde [0.0 [0.0 0.05 [0.05 ater | To 100 [To 100 [To 100 To 100

Stability Good Poor Good Good test against attack by fungus

The data in Table 5 indicates that bars prepared as per composition of the prior art (Comparative Example G which had sugar but no stabilising agent, e.g. formaldehyde) had poor stability. Compositions as per the invention (Examples 3 and 4) were comparable to higher TEM composition of the prior art without sugar (Comparative Example F) in terms of microbial stability, but could be prepared at much lower cost.

Claims

1. A non-granuiar solid cleaning composition comprising (a) 50 % to 70 % salt of fatty acid (b) 1 % to 15 % of a mono or disaccharide and (c) 0.02 $ to 2 % of a stabilising agent

2. A non-granular solid cleaning composition as claimed in claim 1 additionally comprising 0.2 % to 6 % of free fatty acid of carbon chain length 8 to 22.

3. A non-granular solid cleaning composition as claimed in claim 1 or claim 2 additionally comprising 0.1 % to 2% alkali metal carbonate or bicarbonate.

4. A non-granular solid cleaning composition as claimed in any of claims 1 to 3 wherein the composition is in bar form.

5. A non-granular solid cleaning composition as claimed in any preceding claim wherein the stabilising agent is chosen from formaldehyde, benzoic acid, or sodium benzoate.

6. A non-granular solid cleaning composition as claimed in any preceding claim wherein the stabilising agent is present in an amount of 0.05 % to 1 % by weight of the composition.

7. A non-granular solid cleaning composition as claimed in any preceding claim wherein the salt of fatty acid is present in an amount of 50 % to 70 % by weight of the composition.

8. A non-granular solid cleaning composition as claimed in claim 7 wherein the salt of fatty acid is present in an amount of 55 % to 68 % by weight of the composition.

9. A non-granular sclid cleaning composition as claimed in claim 8 wherein the salt of fatty acid is present in an amount of 58 % to 68 % by weight of the composition.

10. A pon-granular solid cleaning composition as claimed in any preceding claim wherein the iodine value of the fat charge is in the range of 30 to 50.

11. A non-granular solid cleaning composition as claimed in claim 10 wherein the iodine value of the fat charge is . in the range of 38 to 42.

12. A non-granular solid cleaning composition as claimed in any preceding claim wherein the mono- or disaccharide is chosen from glucose, sucrose, mannose, or fructose.

13. A non-granular solid cleaning composition as claimed in any preceding claim wherein the mono- or disaccharide is present in an amount of 6 % to 12 % by weight of the composition.

14. A non-granular solid cleaning composition as claimed in any preceding claim wherein the free fatty has a carbon chain length of 10 to 14.

15. A non-granular solid cleaning composition as claimed in claim 14 wherein the free fatty acid is saturated.

16. A non- granular solid cleaning composition as claimed in any preceding claim wherein the alkali metal carbonate or bicarbonate is present in an amount of 0.2 % to 1.5 % by weight of the composition.