US 3247121 A
Description (OCR text may contain errors)
United States Patent Ofifice 3,247,121 WASHING COMPOSITION Milton Henry Hendricks, Cincinnati, Ohio, assignor to The Procter & Gamble Company, Cincinnati, Ohio, a corporation of Ohio No Drawing. Filed Apr. 30, 1962, Ser. No. 191,271 7 Claims. (Cl. 252-117) This invention relates to personal use washing compositions in the form of a bar. Specifically, it relates to an improved milled toilet bar containing soap, which bar does not crack or smear objectionally during use.
The ordinary bar of soap has generally acceptable physical characteristics during ordinary usage. However, when a bar is in continuous contact with water, such as might occur while the bar is sitting in a soap dish, the bar takes up water, which softens the bar surface. This softening of the bar results in a slimy appearance and feel and also results in wastage. The softened portion of the bar is referred to as smear. Excess smear is undesirable because it results in bar wastage and in washstand mess. Some smear is unavoidable since a bar which lathers well invariably has some smear. Also, it often becomes advantageous to add a synthetic detergent surfactant to the bar to achieve certain advantages in cleaning and prevention of the deposition of insoluble fatty acid soaps in the form of a curd. When this is done, the physical properties of the bar are often harmed and the bar smears even more objectionally,
Accordingly, it is an object of this invention to provide a milled b-ar containing soap and having a markedly reduced tendency to smear.
It is a further and more specific object of this invention to provide a milled soap-synthetic bar having excellent performance characteristics as hereinafter more fully described.
The objects of this invention can be achieved in a milled bar comprising an intimate admixture of:
(1) from about 50% to about 80% of soap having from about 8 to about 20 carbon atoms, at least 15% by weight of said soap having from about 8 to about 14 car bon atoms and the rest having from about 14 to 20 carbon atoms, the cation of said soap being selected from the group consisting of sodium and a mixture of sodium and potassium cations such that no more than about 25 by weight of said soap is potassium soap;
(2) from 0.0 to about 0.85 part per part of soluble soap of a compatible synthetic detergent surfactant;
(3) from about 0.5% to about 30% of an alpha sulfonated fatty acid compound, which improves smear characteristics, having the formula:
wherein R is an alkyl chain containing from about 6 to about 20 carbon atoms, and X and M are cations selected from the group consisting of alkali metal, ammonium, monoethanolamine, diethanolamine, and triethanolamine, magnesium, and hydrogen cations;
(4) from 0.0 to about 0.30 part per part soluble soap, but no more than about of fatty acid having from about'lO to about carbon atoms;
(5) from about 0% to about 15% of water; and
(6) from about 2% to about 12% of alkali metal inorganic salts.
All percentages herein are by weight of the bar unless otherwise stated.
Filler materials, minor additives and inert ingredients, if desired, can make up any balance.
The sodium and potassium soaps which are used in for- 3,247,121 Patented Apr. 19, 1955 mulating these bar-s are the soaps of higher fatty acids. The soap will normally be no more than about 25 by Weight potassium soap Since the presence of potassium soap will tend to make the bars softer. Although a range of specific chain lengths is given, it will be under-stood that the use of mixtures of these acids derived from natural sources is usual in soap preparation. When the term cononut oil is used herein in connection with free fatty acid and soap it refers to fatty acid mixtures having an approximate carbon chain length distribution of: 8% C 7% C 48% C 17% C 9% C 2% C oleic, and 20% linoleic (the first six fatty acids listed being saturated). Other sources having similar carbon chain length distribution such as palm kernel oil and babassu kernel oil are included within the term coconut oil. When the term tallow is used herein in connection with free fatty acid and soap it refers to fatty acid mixtures having an appropriate carbon chain length distribution Of C14, C16, C18, palmitoleic, oleic, and 3% linoleic (the first three fatty acids listed are saturated). Other mixtures with similar distribution, such as the fatty acids derived from various animal tallows and lard, are also useful. Coconut oil fatty acids ordinarily have a sutiiciently low content of unsaturated fatty acids to have satisfactory keeping qualities without further treatment. As is customary, however, the fatty acid-s are hydrogenated to decrease the amount of unsaturation (especially polyunsaturation of the fatty acid mixture listed above).
Less than about 50% of soap in the bar is not desirable from the standpoints of cost, physical characteristics of the bars, such as gumminess and smear, and lathe-ring performance. More than about of soap should not be used in order to allow sufficient alpha sulfonated fatty acid compound, compatible synthetic detergent, water, etc., to be incorporated in the bar.
At least 15 of the soap used in these bars and preferably more, should be of the shorter chain fatty acids of from about 8 to 14 carbon atoms, prefer-ably coconut oil soap, in order to provide good lathering properties. At least 25% of these shorter chain fatty acids should contain 12 carbon atoms for the same reason. It is desirable, however, that a substantial portion of the soap has fatty acid chain lengths of from 14 to 20 carbons, preferably tallow soap, in order to impart creaminess and mildness to the lather. The soap will ordinarily be prepared from hydrogenated fatty acids with an Iodine Value (I.V.) of from about 1 to about 55. The tal-low fatty acids will ordinarily have an I.V. of from about 40 to about 55 and the coconut fatty acids Will ordinarily have an I.V of from about 1 to about 8.
Compatable synthetic detergent surfactants can be present in an amount from 0.0 to about 0.85 part per part of the soap. Preferably, if a synthetic detergent surfactant is used, there should be at least 0.05 part of said surfactant per part soap in order to achieve the benefits of increased detergency and reduced deposition of insoluble soap curd. The maximum amount is set by the presence of the other bar ingredients and the physical characteristics of the bar. Too much synthetic detergent surfactant makes it difficult to keep smear from becoming objectionable. This synthetic detergent surfactant can be selected from a wide class of anionic detergent surfactants. Selection of this surfactant is made on the basis of lathering and curd dispersing characteristics, physical characteristics of the bar, and economic considerations. Examples of anionic synthetic detergent surfactants which can be used in the bar are: alkyl glyceryl ether sulfonates; alkyl sulfates; alkyl monoglyceride sulfates and sulfonates; alkyl polyethenoxy ether sulfates; acyl sarcosinates; acyl esters of isethionates; acyl N-methyl taurides; alkyl benzene sulfonates; and alkyl phenol polyethenoxy sulfonates, wherein the can be removed with a spatula.
alkyl and acyl groups, respectively, contain from about to about carbon atoms. Other anionic synthetic detergents include dialkyl esters of sulfosuccinic acid (e.g., the dihexyl ester); the sulfated and neutralized reaction product of a fatty amine and hydroxy acetic acid; the salts of the higher fatty alcohol esters of sulfo carboxylic acids (e.g., sodium salt of the lauroyl ester of sulfo acetic acid); and the salt of an ester of a straight chain primary alcohol and an alpha sulfonated fatty acid (e.g., the sodium salt of the methyl ester of alpha Snlfonated tallow fatty acids). These compounds are used in the form of water-soluble salts, for example, the sodium, potassium, ammonium, and alkylammonium salts. Specific examples include sodium lauryl sulfate; potassium N-methyl lauroyl tauride; triethanolamine dodecyl benzene sulfonate; and sodium coconut alkyl glyceryl ether sulfonate.
The addition of an alpha sulfonated fatty acid compound as hereinbefore described, to the bars of this invention, improves the physical characteristics, such as smear, of a bar containing soap and improves the character of the lather (voluminous, thick, small bubbles). There is also a reduction, especially in a bar containing only soap and said alpha sulfonated fatty acid compound, in the amount of soap curd formed; the sulfonated fatty acid compound acts as an effective curd dispersant.
The effect of the inclusion of the alpha sulfonated fatty acid compound upon smear is quite unique; in general, the addition of the sulfonated fatty acid compound to a soap-containing bar improves smear properties, i.e., decreases the amount of smear. This advantage can better be understood, however, by a more precise definition of bar smear. In general, bars in use form at least two distinct layers of smear which are evident on examination. There is an outer layer of smear which is very soft and which is readily distinguishable visually and there is normally an inner layer of smear which is not readily distinguishable visually. The outer layer can be removed by means of a light wipe with a finger and the inner layer The total of these two smear layers is much less for the bars of this invention after prolonged soaking in a soap dish, such as would occur overnight, than in a similar bar which does not contain the alpha sulfonated fatty acid compound. The outer layer of smear is also less, but an even more dramatic improvement in the character of the smear is obtained in the bars of this invention. The outer layer of smears in ordinary bars containing soap is fairly viscous, pasty, and stringy. The characteristics slimy feel of this smear is considered objectionable by many people. This outer layer in ordinary bars remains as a discrete phase when placed in water and does not readily disperse. Therefore, when the consumer uses the bar the smear adheres to the hands throughout most of the washing process creating a distasteful situation. The addition of the smear improving compound of this invention, in even small amounts to ordinary soap boars, changes the character of this smear. The outer layer of smear of the bars of this invention is immediately dispersible in water so that the user of the bar is not so forcibly reminded of the amount of the bar which is wasted and after an initial application of water the user of the bar is able to use a bar with an acceptable firm feel instead of a viscous, slimy, pasty feel. In order to achieve noticeable improvement in smear characteristics at least 0.5% by weight of the bar of soap of the alpha-sulfonated fatty acid compound should be included. The maximum amount of by weight of the bar is determined by physical characteristics of the bar such as cracking. The carbon chain lengths for the alpha sulfonated fatty acid compound (C C are chosen so as to give maximum smear improvement and not to provide a bar which is either too soft or too hard. in a milled bar the maximum amount of alpha sulfonated fatty acid compound used should be about 20% since the compound is electrolytic in charderived from natural sources.
3. acter and salt crystallization, wet cracking, and insolubility become problems at higher levels.
Examples of the alpha sulfonated fatty acid compound include the monosodium and disodium salt of alpha sulfonated tallow fatty acids, the monoand dimagnesium salts of alpha sulfonat-ed palmitic acid, the triethanolammonium salts of a-sulfonated stearic acid and alpha sulfonated tallow fatty acid.
The fatty acids which are used as such in the preferred bars of this invention vary in carbon chain length from about 8 to about 20 carbon atoms. It will be understood that the usual usage is of mixtures of fatty acids A preferred mixture of fatty acids is coconut oil fatty acids as hereinbefore described. These acids preferably constitute a substantial portion of the fatty acids used in the bar and the rest is preferably tallow fatty acids as hereinbefore described.
Fatty acids that are longer in chain length than about 20 carbons are too hard for desirable bar properties and fatty acids shorter in chain length than about 8 carbon atoms are too soft for advantageous inclusion in a bar. Therefore, the fatty acid component of the preferred bar should range in carbon chain length from 8 to 20 carbon atoms. The I.V. of these free fatty acids will normally range from about 1 to about 30. The tallow fatty acids will have an I.V. of from about 10 to about 30 and the coconut fatty acids will have an I.V. of from about 1 to about 8. This fatty acid should be present in an amount from zero to about 0.30 part per part soap, but not more than about 15% by weight of the bar. Preferably, .in milled bars, and in bars containing a synthetic detergent surfactant, a minimum of 0.05 part per part soap is used in order to plasticize the bar and, build the lather and improve lather qualities. More than about 0.30 part per part soap of the fatty acid is undesirable since any further increase results in a decrease in these properties. Less than 0.05 part per part soap of the fatty acid can be used but without substantial improvement in these lather properties.
Alkali metal inorganic salts, e.g., potassium and sodium sulfates and chlorides, are present in the bar to firm the bar and to aid in preventing undesirable smear. In the bars of this invention there is a minimum of about 2% of these inorganic salts. Excess inorganic salts tend to crystallize at the surface of the bar, creating an unacceptable surface. Preferably, from about 4% to about 10% by weight of the bar is made up of inorganic salts. As long as inorganic salts are not present in amounts above the 2% to 12% range, bar firmness and smear characteristics can be improved without unacceptable surface crystallization.
There is, as hereinbefore mentioned, from about 0% to about 15 by weight of the bar of water. For a conventional milled bar the water level should be between about 2% and about 12% by weight of the product. Less water than this preferred range of 2% to 12% results in bar stock which is difficult to process and more water than this preferred range results in bar stock which is difiicult to process and which may even result in bars :hich are soft in use. Even within this 2-12% range, high water levels are only used with low levels of free fatty acid since both water and fatty acid act as plasticizers.
Various inert ingredients such as insoluble soap, starch, finely divided clays, etc., may be added, if desired, in amounts up to about 15 of the bar without altering the desirable bar characteristics of this invention.
Other additives commonly included in toilet bars, such as coloring matter, perfume, antimicrobial agents and the like, can be used, if desired, in the bars of this invention without detracting from the desirable properties of the bars.
The bars of this invention can be prepared by forming a homogeneous aqueous mixture of the soap, alpha sulfonated fatty acid compound, inorganic salts and, if
desired, a compatible synthetic detergent surfactant, and drying this mixture to granules or flakes containing 0% to moisture. This granular material is then blended with the free fatty acid component and additional water as necessary and formed into a bar by milling, plodding, etc., and then stamping in conventional manners. The fatty acid can be added before drying of the aqueous mixture, if desired.
The following example is illustrative of the practice of this invention.
Example 1' The bars of this example were for-med by adding the soap; the salts of the alpha sulfonated fatty acids; the synthetic detergent surfactant; the inorganic salts and, all but compositions 9-12, the fatty acid to water in a crutcher to form an intimate aqueous mixture. The mixture was roll-dried to flakes with about 1% moisture. These flakes were then amalgamated with water and the optional ingredients, i.e., dye, opacifier, microbial inhibitor, and, in the case of compositions 9-12, fatty acid, and a bar was formed by milling at approximately 96 F. on a three-roll mill for three passes, plodding and replodding at about 108 :F. and cutting and stamping. the bars in conventional equipment.
The term coconut, as referred to in these examples applies to a distribution of carbon chain lengths which is approximately as follows: 8% C 7% C 48% C 17% C 9% C 2% C 7% o-leic, and 2% lineolic (the first six fatty acid-s listed are saturated). The term tallow as referred to in these examples indicates a carbon chain length distribution approximately as follows: C 2.5%, C 28%, C 23%, palmitoleic 2%, oleic 41.5%, and linoleic 3% (the first free fatty acids listed are saturated).
These bars were tested for smear by cutting off one side of the bar to form a fresh surface and placing the bar on inch rods in a shallow dish with 40 cc. of water. After soaking for about 18 hours, the sme-ar was removed by lightly wiping the surface with finger. This smear was dried and weighed. The results are reported in grams of smear.
6 desirable characteristic, as hereinbefore described, of dispersing. readily in water.
Substitution of other synthetic detergent surfactants, e.g., sodium coconut al kyl sulfate, sodium dodecyl benzene sulfonate, and sodium coconut alkyl ethylene oxide ether sulfate for the synthetic detergent surfactants of compositions 5-16 provides substantially equivalent results. Substitution of soaps derived from other sources having similar chain length distributions to coconut and tallow soaps such as palm kernel oil, babassu kernel oil, lard, and other animal tallow soaps can be substituted for the soap of compositions 1-16 with substantially equivalent results.
It is understood that compositions 1, 5, 9 and 13 are blanks and that composition 4 is outside the scope of the invention since it was tested for lathering and failed to lather at all. In general, the other bars, when tested, proved to be very good lathering bars having excellent physical properties.
Bars with the following composition are especialy advan-tageous.
19% Sodium salt of coconut glyceryl ether sulfonate;
31% sodium coconut soap;
23% sodium tallow soap;
10% 1:1 mixture of coconut and tallow fatty acid;
2 /2% disodium salt of alpha sulfonated tallow fatty acids;
8% alkali metal inorganic salts;
4% water; and
2 /2% miscellaneous.
What is claimed is:
1. A personal use milled toilet bar consisting essentially of:
(1) from about to about 80% by weight of soap having from about 8 to about 20 carbon atoms, at least 15% by Weight of said soap having from about 8 to 14 carbon atoms and any remaining soap having from about 14 to about 20 carbon atoms, the cation of said soap being selected from the group consisting of sodium and a mixture of sodium and potassium cations such that no more than 25% by weight of the soap is potassium soap;
COMPOSITION (PERCENT BY WEIGHT) Compositions 1 3 4 5 7 s 9 10 11 12 13 14 15 10 Sodium coconut soap 34.2 29.9 27.9 20.2 35.9 35.3 34.8 33.6 32.5 32.5 32.5 32.5 53.6 56.6 52.0 40.7 Sodium tallow soap 51.0 38.0 28.2 33.0 27.1 20.7 26.2 25.4 24.5 24.5 24.5 24.5 Disodium iii-sulfonated tallow fatty acid 2. 5 5. 0 10. 0 Coconut fatty acid 7.5 5.0 0 5.1 5.1 5.1 5.1 2.9 2.8 2.7 2.5 Tallow fatty acid 0 0 0 5. 1 NaCl 8.6 0.3 7.2 7.5 7.5 7.5 7.5 s s s a 11 0 a 7.5 12 4 4 4 4 10 10 10 10 Sodium salt of methylester of asulionated tallow fatty acid 12.4 12.2 11.8 Sodium coconut glyceryl ether sulionate 20 20 20 20 20.5 19.8 12.5 17.4 Monosodium a-sulionated tallow yac' 5.1 5.1 Monosodiurn iii-sulfonated palmitic acid 5.1 2.8 7.9 12.4 Disodium tit-sulfonated palmitic acid 0 7.4 14.4 35.4 Smear @1115.) 2.1 1.5 1.1 0.3 11.5 8.4 3.6 1.9 10.1 5.7 7.4 9.4 17.3 5.3 2.6 1.9
1 Stearic acid substituted for tallow fatty acid.
As can be seen from this data, the addition of salts (2) from 0.0 to about 0.85 part per part by weight of alpha sulfonated fatty acids to bars containing soap of the soluble soap of a compatible non-soap aniresults in improved smear. In compositions 1-4, addlonic synthetic detergent surfactant; tion of the salt effected decreased smear. In com-posi- (3) from about 0.5% to about 30% by Weight of a tions 5-9, substitution of the salt for coconut fatty acid compound, which improves smear characteristics, eifected decreased smear in a bar containing another with the formula: synthetic detergent surfactant in addition to the salt H O itself. Similarly in compositions 9-12 and 13-16, sub u stitution of the salt for tallow fatty acid and for coconut R CC OTM soap respectively also effected a decrease in smear. S 03X The outer layer 0f smear on these bu-IS containing the wherein R is an alkyl chain containing from about salts of alpha sulfonated fatty acids also exhibited the 6 to ab ut 20 carbon atoms nd X d M are cations selected from the group. consisting of alkali metal, ammo nium, monoethanolamine, diet-hanolamine, triethanolamine, hydrogen and magnesium cations.
(4) from 0.0 to about 030 part per part by weight of the soluble soap but not more than 15% by weight of fatty acid having from about 8 to about 20 carbon atoms;
(5) from about 0% to about 15% by weight of water;
(6) from about 2% to about 12% by weight of alkali metal inorganic salts selected from the group sisting of sodium sulfate, sodium chloride, potassium sulfate and potassium chloride.
2. The composition of claim 1 containing at least 0.05 part per part by weight of the soap of a compatible non-soap anionic synthetic detergent surfactant; no more than 20% by weight of component 3; at least 0.05 part per part by weight of the soap of fatty acid having from about 8 to about 20 carbon atoms; from 2% to about 12% by weight of water; and from about 4% to about by weight of component 6.
3. The composition of claim 2 wherein the compatible non-soap anionic synthetic detergent surfactant is sodium alkyl glyceryl ether sulfonate, the alkyl group containing from about 10 to about 20 carbon atoms.
4. The composition of claim 1 in which component 3 is derived from tallow fatty acids.
5. The composition of claim 4 in which component 3 is in the form of its disodioum salt.
6. The composition of claim 2 wherein the compatible non-soap anionic synthetic detergent surfactant is the sodium salt of the methyl ester of alpha sulfonated tallow fatty acids.
7. The composition of claim 1 wherein at least 20% by weight of the soap has chain lengths higher than 14 carbon atoms.
References Cited by the Examiner UNITED STATES PATENTS 2,303,212 11/1942 Kise 252121 2,867,586 1/1952 Weil 252-16l XR 2,894,912 7/l959 Geitz 252-417 XR 2,965,575 12/1960 Beaver et a1. 252107 2,988,511 6/1961 Mills et al. 25212l 3,043,778 7/1962 Kelly 252--117 XR 3,076,766 2/1963 Anstet-t 252-117 JULIUS GREENWALD, Primary Examiner.
I. T. FEDIGAN, Assistant Examiner.