CA1094910A - Toilet bar soap - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A toilet soap bar comprising soap, water-soluble hydrolyzed protein having a molecular weight in the range of 600 - 12,000 and water-soluble poly (ethylene oxids) of molecular weight at least 100,000 which has improved characteristics such as hardness, toughness, wet slipperiness, etc. and good resistance to sloughing.

Description

TOILET SOAP BAR
This invention relates to toilet soap bars.
It has now been found that the inclusion of poly (ethylene oxide) of very high molecular weight in a -toilet soap bar containing the hydrolyzed protein significantly improves the characteristics of the bar.
As is well known alka]ine toilet soap bars are slippery when wetted, and give a slippery lather. Synthetic detergents on the other hand, do not have this property and, in an effort to overcome this defect, poly (ethylene oxide) of very high molecular weight (sold under the trademark "Polyox") has been included in toilet bars composed predominantly of such detergents. The use of polyethylene oxide of high molecular weight for that purpose is described in chapter 9 of the book "Water Soluble Resins" by Robert L. Davidson and Marshall Sittig published 1962 by Reinhold, ~ew York, Particularly at pages 197-198. This same book also describes (at page 198) the use of the Polyox in face creams, hand creams, shaving preparations and s`nampoos, stating "In creams and lotions based on soap, such as vanishing creams, Polyox resin depresses foam and thereby contributes to ease of man-ufacture and fill. The resin also reduces the tendency to soap-up during application".
In accordance with one aspect of the invention, a small amount of high molecular weight polyethylene oxide is included in a toilet soap bar containing hydrolyzed protein. The invention makes it possible to provide toilet bars which are hard, tough7 and shiny, have a degree of slipperiness when wetted which is especially pleasant to the user, give a lather which is creamy, pleasant, siIky and effective, have good resistance to sloughing in use despite a high moisture pickup, have long use lives and are flexible and tough even after much of the bar has been used up, and provide a beneficial effect on the hands (e.g. reduce chapping and flaking, moisturizing the skin, particularly for dry skins).

10~4L910 Detailed Description of the Invention According to the present invention, there is provided a toilet soap bar comprising, by weight, at least 60% of soap, 0.1% to 10% of water-soluble hydrolyzed protein and 0.5% to 10% of poly (ethylene oxide) of mol-ecular weight at least 100,000.
Preferably, the hydrolyzed protein is a callagen hydrolysis prod-uct.
Furthermore and preferably, the poly (ethylene oxide) has a mol-ecular weight of about 300,000 to about 400,000, and the bar further con-tains 1 to 5% of acetylated lanolin as superfatting agent, 0.2 to 3% of glycerin and 1 to 3% of sodium coco isethionate.
Thus, the soap constitutes at least 60%, and preferably more than70% of the moisture-free weight of the bars of the present invention. The soap may be of a conventional type consisting predominantly of 12 to 18 car-bon atom molecules and may be produced by the saponification of fatty mate-rials suitable for use in soap making, suitable fatty materials comprising, for example, the fats, oils and waxes of animal, vegetable, and marine ori-gin, and the fatty acids derived therefrom or of synthetic origin. More specifically, the fatty acids may be of mixed character such as are derived from natural or hydrogenated tallow, cottonseed oil, coconut oil, palm oil, palm kernel oil, babassu nut oil, grease, fish oils, and fatty acids de-rived therefrom by hydrolysis or saponification or may be pure materials such as lauric, myristic, palmitic, stearic and oleic acids. It is general-ly preferred to use in the present invention the sodium salts of the mixed fatty acids derived from tallow and coconut oil and mixtures thereof. A
desirable blend has a weight ratio of sodium coco soap to sodium tallow soap in the range of about 50:50 to about 10:907 with a ratio below about 30:70, e.g. a range of about 25:75 to about 17:83 being especially preferred. As is known in the art, the higher coco contents give faster more copious lather but more irritation, in conventional soaps. It is within the broader scope 1094C~10 to use blends of the sodium soaps and the corresponding potassium soaps (e.g. in mole ratios of sodium:potassium of 90:10 or 75:25).
A particularly preferred hydrolyzed protein is Protein A sold by Croda Inc., New York, N.Y. and is a partially enzymatically hydrolyzed pro-tein derived from beef collagen and characterized by having a zero Bloom gram gel strength, a 10% weight/weight water solution having a viscosity range of about 16--25 millipoises (mps), a p~ of 5.5-6.5, and in weight per-cent, a hydroxyproline content (mainly chemically combined hydroxyproline) of about 10-12%, a nitrogen content of about 15-18%, and a total nitrogen as amino nitrogen of about 5-12%, and a molecular weight of about 1,000 to about 3,000, such as about 2,000. Its ash content is generally low (e.g.
below 10%). Other hydrolyzed proteins which may be used include hydrolysis products comprising proteoses, peptones, and/or polypeptides, typically hav-ing a molecular weight of at least about 600 and below about 12,000, pref-erably below about 5,000, and including moieties of a plurality of amino acids. These hydrolysis products may be formed by partial enzymatic hydrol-ysis, such as by the action of trypsin, erepsin or pancreatic enzymes on protein material (e.g. at about 35-50 C for about 12-48 hours). The par-tially degraded protein may also be a product obtained by partial hydrolysis of protein by heat and/or alkali. Proteins partially degraded by heat may be prepared, for instance, by heating proteinaceous material such as bones, feet, or skin of pork or beef wh ch has been reduced to small pieces and im-mersed in water, by autoclaving at about 2.8 - 3.5 kg/cm of saturated steam (i.e. about 141.5 - 147.6 C) for about two hours; three phases including fat, the desired aqueous phase, and a residue may thus be obtained; the ~ ;
aqueous phase which may contain about 8-10% solids may be concentrated in vacuo to about 50-60% solids at 60-71 C to obtain a "solubilized collagen,"
a heat degraded protein, which may be employed in this invention. Typical proteins which may be partially hydrolyzed for use in accordance with this 3Q invention include casein, gelatin, collagen, albumin, zein, gliadin, 1~94910 keratin, fibroin, globulin, glutenin, etc. Typical commerical partially enzymatically hydrolyzed proteins include Bacto-Proteose (sold by Difeo Laboratories, Detroit, Mich.), proteose-peptone, casein-peptone, gelatin-peptone, Bacto-Peptone (sold by Difeo Laboratories), vegetable peptones, such as soybeans peptone, Proto-Peptone (sold by Wilson Co., the peptone enzymatically derived from solubilized collagen using ground frozen pancre-atic enzymes having a pH of 8, digestion being at about Lg C for about 12-48 hours, the solubilized collagen being derived by heating bones, feet or skin of pork or beef). The preferred proteins are solubilized beef collagen and solubilized pork collagen which may be prepared as described and are gener-ally characterized by a gel strength of about zero Bloom grams.
The partially hydrolyzed protein may have a relatively broad spec-trum of molecular weights and may contain some (usually small amounts) of almost completely degraded polypeptides, such as dipeptides and tripeptides and even some amino acids as a result of the degradation process. If de-sired, these may be removed by dialysis, e.g., by placing the partially de-graded protein in a cellophane bag which is then closed at both ends and is lowered into a tank into which deionized water continuously enters and from which it continuously exits, products such as the tripeptides, dipeptides, and aminoacids pass out of the cellophane by dialysis to mix with the de-ionized water and leave the partially degraded protein. When employed, the dialysis procedure has the additional advantage of removing the odors of the more completely hydrolyzed material.
The proportion of protein ingredient in the toilet bar is gener-ally above about 0.1% and below about 10%. Amounts in the range of about 1%
to about 5% are preferred with a level of about 3% being especially pre-ferred. For the preferred protein material the 1-5% range provides a hy-droxyproline content of about 0.1 to 0.5%, preferably about 0.3%. The pro-tein ingredient in combination with the other ingredients assists in im-proving the overall properties of the bar, including its skin-moisturizing effect particularly on dry skin, anti-chaping and anti-flaking.
The high ~olecular weight poly (ethylene oxide) has an average molecular weight of at least about 100,000. Examples of such compounds are those sold by Union Carbide Company ~mder the trademark "Polyox". These polymers are nonionic and extremely soluble in water and their molecular weights range from about 100,000 to about 5,000,000 or more. It is pre-ferred to employ polymers having average molecular weights below 1,000,000, more preferably not above about 600,000 such as about 300,000 to 400,000.
The proportion of high molecular weight polymer of ethylene oxide in the toilet bar is generally below about 10% and is preferably more than about 0.5% e.g. at least about 1%, and less than about 5%, more preferably below 4%. For the material having an average molecular weight of about 300,000 a proportion in the neighborhood of 2% has given excellent results. This 300,000 molecular weignt material (sold as Polyox-~S~ N-750) has a viscosity at 25 C for a 2% aqueous solution, of about 40 centipoises (Brookfield Spindle No. 1 at 10 rpm): for a 5% solution this viscosity is about 600-1000 centipoise. Use of say 2% of extremely high molecular weight poly (ethylene oxide), e.g., of 4,000,000 average molecular weight, causes the lather to be pituitous, which is less desirable. According to the manufac-turer the Polyox materials typically have a pH of about 10 (e.g. in 5% solu-tion). Soap typically has a pH in 1% aqueous solution of about 10 (e.g.
10.2).
The poly (ethylene oxide) is generally supplied as a powder and typically has the following particle size distribution when a sample thereof is screened through a series of sieves, expressed as weight percent retained on the indicated Sieve No. screen (United States Sieve Series): No. 20-5.2%;
No. 40-31.2%; No. 60-20.7%; No. 100-16.7% and through No. 100-balance. It is often preferable to use a finer particle size poly (ethylene oxide) hav-ing the following distribution as measured above: No. 20-0.3%; No. 40-13%;
No. 60-13%; No. 100-13.g% and through No. 100-balance.

- 1094'910 Milled plodded soaps typically are made up of fine crystals of hydrated fatty acid salt. The high molecular weight poly (ethylene oxide) appears to have an affinity for the moisture in the soap as shown by the ex-periment in Example I, but the physical state of the material in relation to the soap crystals is not presently known.
The bar may also contain a synthetic surfactant of high foaming characteristics in hard water, such as alkali metal salts of organic sul-furic reaction products having in their molecular structure an alkyl radical of from about 8 to about 22 carbon atoms, e.g., alkyl benzene sulfonates, coconut oil fatty acid monoglyceride sulfonates and sulfates, alkali metal fatty acid (C10-C16) isethionates, among others, present in small amounts in the bar. A particularly preferred ester is sodium coco isethionate sold as Igepon* AC-78 by the General Aniline and Film Corporation. The proportion of synthetic surfactant is generally within the range of about 0.5% to about 5% and preferably about 1% to about 3% e.g., about 2%. Preferably the weight ratio of synthetic surfactant to high molecular weight poly (ethylene oxide) is in the range of about 2:1 to 1:2, such as about 1:1.
In addition to the components listed above, it will be understood that the cleansingbar of the invention may contain other conventional addi-tives in minor amounts including those usually found in such cleansing bars,such as fillers, perfumes, dyes fungicides, humectants, (e.g., 0.2 to 3% of glycerine) and bactericides. Additionally, if desired, superfatting agents, may also be included in the bar to impart special effects on the skin. It is found that in the bars of this invention acetylated lanolin (such as, Modulan* sold by American Cholesterol; see United States Patent ~o.

2,725,334 gives especially good results). Other superfatting agents are hydroxylated lanolin, (e.g., OH Lan sold by American Cholesterol), higher (C10-C20) fatty acids such as stearic acid, coconut oil fatty acid, higher (C10-C20) fatty alcohols, petrolatum and the like. Amounts of superfatting agents less than 10% total are generally employed, preferably about 1% - 5%

*Trademark - 6 -`` ~094'910 e.g., 2% - 3% .
The invention is particular]y suitable for the making of milled and plodded toilet soap bars. Bars of this type are of course, well known in the art; see for instance the description thereof in United States Patent

3,179,596. Also see "Encyclopedia of Chemical Technology", Volume 12, ed-ited by Kirk and Othmer, pages 573-598 and "Industrial Oil and Fat Products", Alton E. Bailey, Second Edition, 1951, pages 365-386 and o40-865. Thus one may take a kettle soap, form it into dried chips (as described in the fore-going references) and blend it with the various ingredients before milling and plodding.
The moisture contents of the toilet bars of this invention are such as to provide a solid non-tacky toilet bar. Preferably they are well below 30%. For a milled, plodded bar they are generally less than 20%, preferably in the range of about 10 to 17%, such as about 13%.
Toilet soap bars range in size from the relatively small hotel size (weighing about 20-30 grams) to the regular size (about 100 grams) to the bath size (about 150 g) to the extra large size (about 200 g). The bars of this invention may be of such sizes, particularly in the range of about 100 to 200 grams. ~he soap may also be aerated, in a manner well known to the art to give lower density (floating) soaps, such as those having a spe-cific gravity of about 0. 8. ~ -The ingredients are preferably brought together in a conventional soap amalgamator by mixing soap chips with the poly (ethylene oxide) powder while the surfaces of said soap chips are in powder-adherent condition with respect to said polyethylene oxide powder, to produce soap chips having poly (ethylene oxide) bonded thereto, then adding other ingredients of said toilet soap bar and mixing said other ingredients with said bonded chips, then forming the resulting mixture into a soap bar. Two preferred processes are (a) add the powdered high molecular weight poly (ethylene oxide) to soap 30 chips having a moisture content such that the powder adhere thereto (e.g. at ~O~9~lO

least about 11% H20) and mixing, before adding the other solid ingredients, or (b) add the powdered high molecular weight polyethylene oxide to soap chips having a lower moisture content, mix, and then carefully add some water in finely dispersed state (e.g. to bring -the water content, based on soap to a level sufficient to provide powder adhesion) before adding the other solid ingredients. This procedure substantially avoids the formation of visible specks comprising poly (ethylene oxide). The reason for this is not understood, but it appears that the particles of high molecular weight poly (ethylene oxide) (whose moisture sorption is below 3% at a relative humidity of 60% at 25 C, according to the manufacturer's bulletins) take up sufficient moisture from the higher moisture content soap chips and become bonded, individually, to the surfaces of the chips so that these particles are thus prevented from agglomerating; if there is not sufficient moisture for this to occur before the subse~uent addition of other solid ingredients (particularly powders of low moisture contents, e.g., below about 8% water), the latter may compete for the limited amount of moisture available, and loose particles of high molecular weight poly (ethylene oxide) may agglomer-ate in later stages.
Various embodiments of the present inven-tion will now be illus-trated by reference to the following specific examples. It is to be under-stood, however, that such examples are presented for purposes of illustra-tion only, and the present invention is in no way to be deemed as limited thereby.
EXAMPL~ I
A soap bar of the following composition is prepared by adding the ingredients in the order listed, to a conventional soap amalgamator (while the blades thereof are moving) operating at room temperature.

10~4C~10 Component Weight %
Soap chips (17 coco Na soap/83 tallow Na soap) 88.50 50% aqueous solution of stannic chloride 0.]5 (a preservative) Poly (ethylene oxide) 2.00 Water 1.00 Titanium dioxide-powder (substantially 0.60 moisture-free), (a pigment) Protein A-powder (containing up to about 3.00 6% moisture Sodium coco isethionate-powder (containing 2.00 about 1-2% moisture) Glycerine 0.50 Acetylated lanolin3 1.00 Perfume 1.25 100 . 00 Moisture i5 about 11.5%; bar moisture 10.5%;
measured by weight loss at 105C.
Poly WSR N-750* in the form of powder, of size such that less than 5% by weight (e.g., 0.3%) is re-tained on a 20 mesh screen (United States Standard).
3Modulan-added in molten state (temperature of about 120 F).
When added to the soap chips in the amalgamator, the individual particles of the homopolymer of ethylene oxide stick to the chips, especial-ly when the water is then sprinkled onto the moving chips. The other ingre-dients are then added in the order indicated, while mixing is continued for a total of about 2 minutes. At this time the mixture is not clumped to-gether, but is still flow&ble, in chip form.

The blend is then milled on a conventional five-roll soap mill to a thickness of about 0.05 to G.l mm the resulting milled chips having a tem-perature of about 34-37 C. The chips are fed directly into a jacketed soap *Trademark _ g _ " 10949~0 plodder and extruded to form a continuous bar ("plodder bar"). The plodding is controlled in one run to produce a plodder bar whose core temperature measured directly after extrusion is about 34-38 C; in a second run the tem-perature is controlled to give a plodder bar core temperature of 40-43 C.
The plodder used is a Doelger-Kirsten eight inch double barrel Vacuum Plod-der, Schwantes Design. The plodder bars are cut in conventional fashion to give units whose volumes are suitable for a toilet bar (e.g., about 140 g for a bath size bar and about 100 g for a regular size bar) pressed in con-ventional metal soap-pressing dies to the final rounded shape of the toilet bar. The units made from the higher temperature plodder bars are more dif-ficult to press, without sticking to the die, but when the same plodder bar is cooled to about 38 C, the pressing is much better.
Examination and use of the bars show a smooth surface, similar to that of normal soap bars. They are hard, tough, and shiny, have a degree of slipperiness when wetted which is especially pleasant to the user, give a lather which is creamy, pleasant, silky and effective, have good resistance to sloughing in use despite a high moisture pickup, have long use lives and are flexible and tough even after much of the bar has been used up and pro-vide a beneficial effect on the hands (e.g., reduce chapping and flaking, moisturizing the skin, particularly for dry skins).
EXAMPLE II
Example I is repeated except that the sodium coco isethionate is omitted from the formulation and the soap content is correspondingly in-creased.
EXQ~PLE III
Example I is repeated except that the acetylated lanolin is omitted from the formulation and the soap content is correspondingly increased.
EXAMPLE I~
Example I is repeated, except that the coco and tallow soap ratio is 25!75, the soap chips have a higher moisture content (about 14%, mois-10~4C~10 ture), there is no separate addition of water (and the bar moisture content is thus about 13%), and higher plodder temperatures are used so as to pro duce a bar having a core temperature of about 50 C. The bar surface is then cooled (with cool air), and a film of pressing lubricant (e.g., an aqueous solution containing 16% NaCl and 25% glycerol) is directly applied to the pressing dies before each pressing operation.
EXAMPLE V
(a) Example I is repeated with the following formulation:
Component Weight %
Soap chips (25 coco/75 tallow) 89.25 50% aqueous solution of stannic chloride 0.15 50% aqueous solution of citric acid (to 0.25 react with any excess alkali) Poly (ethylene oxide) 2.00 Titanium dioxide 0.60 Protein A 3.00 Sodium coco isethionate 2.00 Hydroxylated lanolin 1.00 Glycerine 0.50 Perfume 1.25 100.00 (1) Added as Polyox WSR N-750~
(b) Example V (a) is repeated except that the proportion of poly (ethylene oxide~ is reduced to 1% and the soap content is raised by 1%.
Users prefer the product of Example V (a).
(c) Example V (a) is repeated but a second poly (ethylene oxide), 0.5% Polyox WSR-N-3000* (molecular weight 400,000), is also included and the soap content is correspondingly lowered to 88.75%.
EXAMPLE VI
Example V is repeated except that the sodium coco isethionate is omitted (the soap chips being increased to 91.25%) and the polyethylene ox-ide has an average molecular weight of about 400,000 (Polyox WSR-N-3000)*.

*Trademark - 11 -

Claims (11)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A toilet soap bar comprising, by weight, at least 60% of soap, 0.1% to 10% of water-soluble hydrolyzed protein and 0.5% to 10% of poly (ethylene oxide) of molecular weight at least 100,000.

2. A toilet soap bar as in claim 1 wherein the hydrolized protein has a molecular weight of 600 to 12,000.

3. A toilet soap bar as in claim 1 wherein the hydrolyzed protein is a collagen hydrolysis product.

4. A toilet soap bar as in any of claims 1-3 wherein the poly (ethylene oxide) has a molecular weight of 100,000 to 1,000,000.

5. A toilet bar has in any of claims 1-3 wherein the poly (ethylene oxide) has a molecular weight from 300,000 to 600,000.

6. A toilet soap bar as in any of claims 1-3 wherein the hydrolyzed protein has a molecular weight of 1,000 to 3,000.

7. A toilet soap bar as in any of claims 1-3 wherein the hydrolyzed protein provides a hydroxyproline content of 0.1 to 0.5%.

8. A toilet soap bar as in any of claims 1-3 containing 1% to 5% of the hydrolyzed protein and 1% to 4% of the poly (ethylene oxide).

9. A toilet bar as in any of claims 1-3 further containing 0.5 to 5%
of a synthetic surfactant.

10. A toilet bar as in any of claims 1-3 further containing up to 10%
of a superfatting agent.

11. A toilet bar as in any of claims 1-3 wherein the poly (ethylene oxide) has a molecular weight of about 300,000 to about 400,000, and the bar further contains 1 to 5% of acetylated lanolin as superfatting agent, 0.2 to 3% of glycerin and 1 to 3% of sodium coco isethionate.