CH637158A5 - TOILET SOAP COMPOSITION AND METHOD FOR THE PRODUCTION THEREOF. - Google Patents

Description

The present invention relates to a toilet soap composition and a method for its production.

Over-greased toilet soaps, such as those sold as cosmetic or facial soaps, are generally known and are described, for example, in US Pat. No. 3,576,749 (Megson et al.). In this patent it is stated that such toilet soap bars differ significantly from the soaps made from synthetic detergents, which are very soft and slimy and accordingly unsightly and greasy, which is unacceptable for soap bars, in particular for toilet soaps. According to the cited US patent, free fatty acids in the soap improve the foam volume and the quality of the foam by stabilizing the foam with small air bubbles, which gives the consumer a foam that is characterized as “richer” and “creamier”. The fatty acids also show a tendency to make the skin more supple. From the cited U.S. patent

It can be seen from the writing that relatively large amounts of sodium chloride and relatively high grinding temperatures are required for such over-greased soap bars in order to achieve strength of the soap bar and resistance to smearing.

The present invention relates to a toilet soap composition which is essentially and preferably completely free from synthetic detergents, which also forms a strongly creamy foam and which gives a particularly pleasant feeling during and after use. Compared to the commercially available over-greased toilet soap bars, e.g. According to the teaching of US Pat. No. 3,576,749, it has been found that the toilet soap composition according to the invention is highly preferred by the consumer with regard to the nature of the foam and other properties. The toilet soap composition according to the invention is firm and shows a high resistance to detachment of the outer layer or against smearing, without the incorporation of sodium chloride and without the need for high grinding temperatures.

Accordingly, the present invention relates to a toilet soap composition which is essentially characterized by a content of sodium soap of higher fatty acids with 8 to 20 carbon atoms, 6 to 12% by weight overfatting higher fatty acids with 8 to 20 carbon atoms, 0 , 5 to 4 wt .-% polyethylene oxide with a molecular weight between 100000 and 5000000 and 5 to 18 wt .-% water.

According to one embodiment of the present invention, the toilet soap composition contains e.g. 8 to 10 wt .-%, free higher fatty acids together with at least 0.5 wt .-%, generally 1 to 4 wt .-%, preferably 1.5 to 3 wt .-% of a polyethylene oxide with a molecular weight between 100,000 and 5000000. It has also been found that the over-greased toilet soap composition containing polyethylene oxide, which exhibits particularly good resistance to peeling off of the outer layer or to smearing, contains a sodium soap which is composed in approximately equal proportions of coconut fatty acid and tallow fatty acid with approximately equal amounts of coconut fatty acid and stearic acid, e.g. can be seen from the information compiled in Example 1.

Soap is usually produced by saponification of the fatty acids or esters (eg fats and oils) in a boiling pan 45 or by a continuous process as described in the Encyclopedia of Chemical Technology (2nd edition), volume 18, pages 415 to 425 whereupon the end product of both the kettle and continuous saponification process is a pure soap containing about 30% by weight of water. This 30% by weight water content of the pure soap should be reduced to 10 to 15% by weight before the soap bars can be molded.

Soap bars have so far been commercially available by adding powdered polyethylene oxide to soap flakes in a 55 soap melting kettle. In order to prevent the formation of stains in the soap bar, such an addition must be made under special precautionary measures. The use of high molecular weight polyethylene oxide in pieces of synthetic detergents that can contain some soap is already known. It has been proposed to melt the resin along with the soap, detergent base, or other ingredients and then incorporate other materials into the melt, see Davidson and Sittig, "Water Soluble Resins" (1962), pages 197 to 198. 65 In an attempt to incorporate approximately 2% by weight of powdered polyethylene oxide into a pure soap (- "kettle soap") containing approximately 30% by weight of water, a coarse,

poorly dispersed and non-pumpable mixture obtained.

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According to another embodiment of the present invention, it has been found that a mixture with superior properties is obtained when the polyethylene oxide, preferably in powder form, is incorporated into a melt of part or all of the higher fatty acids used to over-oil the soap . The best results are obtained if this mixture also contains a small amount of water. As can be seen from Example 3, the presence of water has a significant influence on the properties of the mixture of fatty acids and high molecular weight polyethylene oxide. Thus the viscosity of the mixture is considerably reduced and the presence of water also causes the mixture to become opaque, which indicates that a "water-in-oil" type dispersion is formed. The water-containing mixture can easily be pumped. Their viscosity is well below the upper viscosity limit of about 7 or 8 Pa-s, so that the mixture can easily be handled with the help of conventional piston pumps. It can therefore be pumped into the mixture containing the boiler soap without difficulty. The soap bars containing polyethylene oxide produced in this way have excellent properties; they foam well, give the user a particularly pleasant feeling during and after use, and have a good resistance to the outer layer becoming detached and to cracking when wet.

The present invention enables the manufacture of a toilet soap composition which produces a greasy and creamy but only moderately slippery foam, which is also firm and resistant to outer layer detachment and cracking in use.

Accordingly, the invention further relates to a method for producing said toilet soap composition, which is characterized in that pure soap, which consists of sodium soaps of higher fatty acids with 8 to 20 carbon atoms with a moisture content of 30 wt .-%, with a mixture of Mixes polyethylene oxide with a molecular weight of 100,000 to 5,000,000 in a melt of superfatting higher fatty acids with 8 to 20 carbon atoms and the mixture obtained is subjected to drying conditions.

The following examples are intended to illustrate the invention in more detail. Unless otherwise stated, the quantities given are parts by weight.

example 1

a) 4.5 parts of stearic acid and 4.5 parts of coconut fatty acid are melted at 80 ° C. in a kettle equipped with a stirrer. 1.8 parts of a high molecular weight polyethylene oxide (Polyox WRS N-750, manufacturer Union Carbide, a polyethylene oxide with a molecular weight of about 300,000 and a viscosity, measured in a 5% aqueous solution, of about 0.550 to 0.900 Pa-s at 25 ° C and a melting point of about 65 ° C) were added with stirring while the mixture was kept at a temperature of 80 ° C. This mixture was then mixed at 70 ° C. with kettle soap in such proportions that the mixture obtained contained about 75 parts of sodium soap (expressed as anhydrous soap), 4.5 parts of stearic acid, 4.5 parts of coconut fatty acid and 1.8 parts of polyethylene oxide. The kettle soap was prepared by saponifying a 50:50 mixture of coconut oil and tallow with sodium hydroxide solution, extracting the resulting glycerol, washing with an electrolyte solution and removing the strongly electrolyte-containing blackish soap layer, as is customary in the production of kettle soap. The soap contained about 27 to 32 weight percent water, up to 1 weight percent (typically 0.5 percent) glycerin, up to about 0.3 weight percent (eg 0.1 percent) sodium hydroxide, and up to about 1% by weight (e.g. 0.7%) NaCl. The additives were stirred together for a few minutes, then the mixture was formed into dry soap flakes containing about 10% by weight moisture. This was achieved by pumping the hot soap mixture onto a chilled roller, forming a thin film on the roller, cutting the film into strips or flakes and then drying them. The soap flakes were then mixed with color and fragrance (about 0.7% by weight of TÌO2 and 1.5% by weight of fragrance) in a conventional manner in a soap melting pot at about room temperature, then homogenized by grinding (for example at about 15 to 35 ° C), then extruded into a bar of soap using a conventional soap extruder (at about 20 to 50 ° C, for example at 40 ° C) and then cut into pieces. The surfaces of these pieces were cooled and then the pieces were pressed into the desired shapes.

b) Part a) was repeated with the difference that instead of 4.5 parts of stearic acid and 4.5 parts of coconut fatty acid, 9 parts of stearic acid were used.

c) Part a) was repeated with the difference that instead of 4.5 parts of stearic acid and 4.5 parts of coconut fatty acid, 9 parts of coconut fatty acid were used.

The soap bars were tested after at least three days of aging and gave the following results:

Sponge-

Releasing the

% Erosion

Hydration

Foam-

outer

(2 hours.)

end-

test

layer

% Increase index

number of

(17 hours)

Strokes

% Loss

35 ° C 37.8 °

C.

a) 60

1.5

2.6 16.1

12.5

18th

b) 80

3.5

2.2 18.8

11.6

15

c) 68

5.2

18.7 19.6

10.8

0

In the sponge-foam test, in which the rate of foam formation is measured, the flat surface of the soap bar is alternately rubbed against a sponge and placed in a pan with water which has a hardness content of 125 ppm and a temperature of 35 ° C., submerged. The up and down movement of the foam apparatus corresponds to the number of strokes required to form a continuous foam ring in the pan. The smaller the number of strokes, the better the foam formation. When checking the peeling of the outer layer, the soap bars are placed with one side flat in a petri dish for 17 hours, then the soft, mushy soap is removed with your hands. The percentage weight loss caused by the detachment of the outer layers is noted. In the erosion test, the soap bar in the foam apparatus is subjected to 260 strokes in about 10 minutes. The soap loss is then measured. In the hydration test, the soap bars are completely immersed in tap water for 2 hours and the weight gain is determined. The crack formation index is based on the number and strength of the cracks found in the soap bars. One side of the soap bars are scraped to half their original size, then placed under tap water with a hardness content of approximately 100 ppm for 1 hour, then removed and hung in the air to dry until there is no sign of free water on the surface is present (usually overnight).

The soap bar from a) showed an unexpectedly high

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4th

Foam formation rate, an unexpectedly low weight loss in the outer layer detachment test and the erosion test and an acceptable cracking behavior.

Example 2

The soap bars were produced as in Example 1 a) with the difference that they additionally contained 0.5% by weight of lanolin with or without 0.5% by weight of solid sodium caseinate, these additives being added to the hot fatty acid / polyethylene oxide Mixture were incorporated before they were mixed with the kettle soap.

Example 3

Example 1 a) was repeated with the difference that the following procedure was used to prepare the mixture with the kettle soap: 5 parts of commercial stearic acid (melting point 54 ° C.) and 5 parts of coconut fatty acid (melting point 25 ° C.; iodine number 6) were used in one Temperature of about 102 ° C melted together. A portion of the powdered high molecular weight polyethylene oxide (“Polyox WSR N-750”, melting point about 65 ° C.) was added with stirring. The viscosity of the mixture was 0.750 Pa • s at 102 ° C, 4 Pa • s at 88 ° C and 5 Pa ■ s at 54 ° C (determined with a Brookfield viscometer). Another part of the polyethylene oxide was then added with stirring. The viscosity of the mixture was about 18 Pa-s at 94 ° C, about 19 Pa-s at 88 ° C, about 33.5 Pa-s at 66 ° C and about 42.5 Pa-s at 54 ° C.

Then 0.5 part of lanolin was added with stirring. The resulting mixture had a viscosity of 15 Pa-s at 94 ° C and a similar viscosity at 70 ° C.

Then 1 part of water was added to the mixture. This made the mixture, which had been clear until then, cloudy or opaque. The viscosity was about 5 Pa-s at 77 ° C, about 4 Pa-s at 71 ° C and about 3,250 Pa-s at 50 to 63 ° C.

An additional part of water was then added with stirring. The mixture obtained now showed a viscosity of about 2.250 Pa-s at 84 ° C, about 1,500 Pa-s at 81 ° C, about 0.930 Pa-s at 71 ° C, and 0.470 Pa-s at 67 ° C, at 60 ° C of 0.234 Pa-s and at 52 ° C of 0.114 Pa-s.

Then 2.5 parts of a sodium caseinate solution containing 20% casein were added. The mixture obtained was white. Its viscosity was about 2,900 Pa-s at 81 ° C, about 2,520 Pa-s at 71 ° C, 1,700 Pa-s at 66 ° C and 1,800 Pa-s at 60 ° C.

When water is added, a mixture is formed whose viscosity e.g. at 70 ° C is greatly reduced, for example, the viscosity can be less than half as high as before the addition of water. The water-containing mixtures also show a significant decrease in viscosity with decreasing temperature, for example when the temperature is reduced by 10 ° C from 70 ° C or 80 ° C, the viscosity drops well over 10%. The resulting mixture was pumped at a temperature of about 60 to 850 ° C into a mixing kettle containing the kettle soap (at 70 ° C) in such proportions that the mixture obtained was about 75 parts of sodium soap (expressed as anhydrous soap), 4.5 Parts of stearic acid, 4.5 parts of coconut fatty acid and 1.8 parts of polyethylene oxide contained.

Example 4

Example 1 a) was repeated, with the difference that 10 parts of stearic acid were melted and 2 parts of the polyethylene oxide were added as in Example 1 in the preparation of the corresponding mixture. While the mixture was stirred and kept at about 70 to 90 ° C, 1.5 parts of water were added.

Example 5

Example 4 was repeated with the difference that coconut fatty acid was used instead of the stearic acid.

The water-containing mixture of polyethylene oxide and the higher fatty acids preferably consists of approximately 2 to 20 parts, particularly preferably approximately 4 to 8 parts fatty acids per part polyethylene oxide and approximately 0.5 to 5 parts, particularly preferably approximately 1 to 2 parts water per Part of polyethylene oxide.

The moisture content in the ingredients added to the kettle soap should preferably be such that the moisture to soap ratio is below about 33:67, e.g. at about 27:73 to 32:68 to reduce the formation of the less desirable gel phases.

It is advantageous to dry in particular the formulations containing relatively large amounts of coconut fatty acids to a moisture content below about 18% by weight, preferably to about 5 to 12% by weight, in order to prevent them from becoming sticky during the later mixing or processing to reduce. For the same reason, it is desirable to maintain relatively low press temperatures, pre-cool and pre-dry the outer surfaces of the soap bars before they are press molded, and lubricate the molds, e.g. with an aqueous solution containing 16% by weight NaCl and 25% by weight glycerin, which is then blown off the surface of the pressed soap bars with air.

The high molecular weight polyethylene oxide has an average molecular weight of at least 100,000. These polymers are non-ionic, water-soluble substances with a molecular weight that is in the range between 100,000 to 5,000,000. Polymers with an average molecular weight below 1,000,000 are preferably used, particularly preferably with a molecular weight not above 600,000, e.g. with a molecular weight of 300,000 to 400,000. When using a material with an average molecular weight of about 300,000, an amount of about 2% by weight of polyethylene oxide gives excellent results. This polymer with a molecular weight of 300,000 has a viscosity of about 0.04 Pa-s in a 2% strength aqueous solution at 25 ° C., measured with the Brookfield spindle no. 1 at 10 rpm. In a 5% aqueous solution, the viscosity is between about 0.600 to 1,000 Pa-s. The use of e.g. 2% by weight of an extremely high molecular weight polyethylene oxide, e.g. with an average molecular weight of 4,000,000, produces a slimy foam, which is less desirable. The polyethylene oxide polymers used generally have a pH of about 10, e.g. in 5% solution. Soap generally has a pH of about 10 in 1% aqueous solution, while the over-greased toilet soap composition according to the invention generally has lower pH values, for example a pH of about 9.5.

The polyethylene oxide is generally used as a powder and usually has the following distribution of particle diameters (the sample is sieved through a series of sieves), expressed in% by weight of the particles on the sieve specified (US sieve series ) are withheld: No. 20: 5.2%; No. 40: 31.2%; No. 60: 20.7%; No. 100: 16.7%; the rest went completely through the No. 100 sieve. Often a finer particle size polyethylene oxide is used which has the following distribution: Sieve No. 20: 0.5%; No. 40: 13%; No. 60: 13%; No. 100: 13.9% and by No. 100 the rest.

The best results were obtained when the soap is saponified to produce a mixture of approximately equal particles of tallow and coconut oil. Generally a sebum: coconut oil ratio of about 2: 1

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up to 1: 2, e.g. 3: 2 or 2: 3, preferred.

Before mixing with the various ingredients, the kettle soap is preferably stabilized, e.g. by incorporating about 0.06% by weight of SnCU and 0.024% by weight of tetra-sodium-ethylenediamine tetraacetate in the form of aqueous solutions.

With regard to the superfatting acids, the best results were obtained when stearic acid and coconut fatty acid were used in roughly equal proportions. In general, these acids are preferably used in a ratio between about 2: 1 and 1: 2, for example 3: 2 or 2: 3. The total amount of over-fatty acids in the toilet soap composition is generally less than about 12% by weight.

It is understood that during the preparation of the soap-fatty acid mixture a cation exchange of sodium and hydrogen ions can occur and that the distribution of the chain lengths in the mixture is best expressed in such a way that the expression summarizes the saponified and unsaponified fatty acids . Such typical distributions in toilet soaps according to the invention are summarized in the following table:

Number of carbon atoms in the fatty acid (the fatty acid a

b is saturated, if not specifically mentioned)

%

%

8th

3.1

2.8

10th

2.9

2.6

12

24.3

21.5

14

11.0

10.5

14 monounsaturated

0.2

0.5

15

0.2

0.3

15 monounsaturated

-

-

16

19.0

18.6

16 monounsaturated

1.0

1.7

17th

0.6

0.4

17 monounsaturated

0.3

-

18th

13.4

12.6

18 monounsaturated

21.6

25.9

18 doubly unsaturated

2.1

2.1

18 triple unsaturated

0.3

0.3

Summary

up to C12

30.3

26.9

C16-C14

31.4

31.6

C18-C17

38.3

41.3

The moisture content, which is said to be less than 12% by weight during the manufacturing process, may increase during use or storage after the soap is made (see e.g. the hydration values in Example 1). However, the results to date show that the toilet soap bars according to the invention have a significantly lower tendency to absorb water than the over-greased soap bars commercially available.

The usual kettle soap contains up to 1% by weight (e.g. 0.7% by weight) of sodium chloride. The toilet soap compositions according to the invention show a good resistance to smearing, without it being necessary to add sodium chloride to achieve this effect, as is proposed, for example, according to US Pat. No. 3576749.

On the other hand, a larger addition of sodium chloride to the toilet soap composition according to the invention is also not harmful. The soap bars according to the invention are distinguished by a good hardness which is comparable to or even better than that of conventional toilet soaps at 32 ° C. when the grinding process is carried out at the usual relatively low temperatures, i.e. their Dietert hardness at 32 ° C is over 85, e.g. at 90 to 92. There is no reason to use a higher grinding temperature, but if they are used, they do not have a detrimental effect on the product according to the invention produced.

Both the type and the relative proportions of the fatty acids and super-fatty acids in the soap are known per se, see e.g. the US-PS 3576749 already cited. Accordingly, these fatty acids have 8 to 20 C atoms. The fatty acids can also contain fatty acids with an odd number of carbon atoms, e.g. a fatty acid mixture can be used, each containing the same proportions of Cu-, C12- and Ci3-saturated fatty acids.

The toilet soap compositions according to the invention can contain customary ingredients, for example opacifiers, e.g. 0.4% by weight of titanium dioxide, added to the amalgamator, furthermore lanolin, for example 0.5% by weight, added to the pure soap, preferably in a mixture with the superfatting agent, glycerol (for example 1% by weight, added in the amalgamator, or in pure soap). Soap perfume (eg 1-3% by weight, such as 1.5-2% by weight, added to the amalgamator) antioxidants (eg 0.02% by weight di-t-butyl-p-cresol or BHI, added) to the pure soap, furthermore proteins, for example 0.5% by weight sodium caseinate, added to the pure soap or as an aqueous solution in the amalgamator Antibacterial or germicidal agents, as mentioned, for example, in US Pat. Nos. 3576749 and 3598746 The invention also encompasses an embodiment in which the soap bars are aerated in a manner known per se, with soaps having a lower density being obtained, for example those with a density of about 0.8.

The toilet soap compositions according to the invention can be produced in soap bars of conventional size, from the relatively small size as they are used as 20 to 30 g bars in hotels to the regular sizes of about 100 g, the bath soap bars from about 150 to to the extra large pieces of about 200 g.

As already mentioned above, the polyethylene oxide polymers can be incorporated in two stages, a part which makes up about half to two thirds of the total amount of the polymer, is incorporated into the pure soap, while the remainder is added to the soap chips in the amalgamator . In order to reduce the tendency to stain, which easily occurs during the last addition to the amalgamator, it proves advantageous to add the polymer in the form of very finely ground material, e.g. such that 98% of a No. 100 sieve (of the U.S. sieve series) can pass and completely distribute the polymer thus pulverized on the surface of the soap scraps in the amalgamator before other ingredients such as e.g. Pigments. If a larger proportion of the total amount of the polymer is already incorporated into the pure soap, the soap is less sticky during the incorporation of the remaining amount of the polymer in the amalgamator, and the amalgamation process can be carried out easily and with less energy expenditure.

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Claims (10)

637 158 1. Toilet soap composition, characterized essentially by a content of sodium soap of higher fatty acids with 8 to 20 carbon atoms, 6 to 12 wt .-% overfatting higher fatty acids with 8 to 20 carbon atoms, 0.5 to 4 wt .-% polyethylene oxide with a molecular weight between 100000 and 5000000 and 5 to 18 wt .-% water. 2. Composition according to claim 1, characterized in that it contains 1.5 to 3 wt .-% polyethylene oxide and wherein the molecular weight of the polyethylene oxide is between 300,000 and 600,000. 2nd PATENT CLAIMS 3. Composition according to claim 1 or 2, characterized in that the sodium soap consists of a mixture of tallow and coconut oil soaps in a weight ratio of 1: 2 to 2: 1. 4. Composition according to claim 1 or 2, characterized in that the sodium soap is a mixture of equal parts of tallow and coconut oil soaps. 5. Composition according to claims 1 to 4, characterized in that the super-fatty acids consist of a mixture of stearic acid and coconut fatty acid in a weight ratio of 2: 1 to 1: 2. 6. Composition according to claims 1 to 4, characterized in that the super-fatty acids consist of a mixture of equal parts of stearic acid and coconut fatty acid. 7. A method for producing a toilet soap composition according to claim 1, characterized in that pure soap, which consists of sodium soaps of higher fatty acids with 8 to 20 carbon atoms and about 30 wt .-% moisture content, with a mixture of polyethylene oxide with a molecular weight of Mixes 100000 to 5000000 in a melt of superfatting higher fatty acids with 8 to 20 carbon atoms and the mixture obtained is subjected to drying conditions. 8. The method according to claim 7, characterized in that a mixture of 2 to 20 parts by weight of the superfatting Ci- to Cio fatty acids per part by weight of polyethylene oxide is used. 9. The method according to claim 7 or 8, characterized in that the mixture contains a small proportion of dispersed water, which is sufficient to lower the viscosity of the mixture. 10. Mixture for carrying out the method according to claim 7, characterized by a content of polyethylene oxide dispersed in Cs to C2o fatty acids with a molecular weight between 100,000 and 5,000,000.