US 3223645 A
Description (OCR text may contain errors)
United States Patent 3,223,645 WASHING CGMPOSITIQN John Nicholas Kalberg, Wyoming, Qhio, assignor to The Procter 8: Gamble Company, Cincinnati, Ohio, a corp-oration of Ohio No Drawing. Filed Apr. 30, 1962, Ser. No. 191,275 4 Claims. (Cl. 252-117) This invention relates to personal use washing compositions in the form of a bar. Specifically, it relates to an improved toilet soap-based bar, preferably a milled bar which has a highly lustrous appearance and which does not smear objectionably during use.
The appearance of a soap bar can be a very important factor in its acceptance by the consuming public. Bars having a flat, dull appearance may sometimes be acceptable and even desirable, but it is felt that a substantial segment of the public desires a lustrous, shiny appearance. The tendency of a bar to form smear by becoming soft when in contact with water in a soap dish is also a factor in consumer acceptance of a soap bar. As between two bars, the one which forms less smear is generally preferred and the bar which tends to return to its original lustrous, shiny condition upon drying is very desirable.
Accordingly, it is a highly important object of this invention to provide a soap-based detergent bar having a highly lustrous and pleasing appearance.
It is a further object of this invention to provide a soap-based bar with a reduced tendency to form smear.
It is still another object of this invention to provide a bar initially having a lustrous and pleasing appearance and which after useand upon drying recovers to the original texture and appearance of the bar.
The objects of this invention'can be achieved in a detergent bar comprising an intimate admixture of (1) from about 40% to about 80% of sodium soap or mixtures of sodium and potassium soaps wherein not more than about 20% of the soap is potassium soap, the soap having from about 8 to about 20 carbon atoms, at least 20% of the total soap having from about 8 to about 14 carbon atoms and the rest having from about 14 to about 20 carbon atoms; (2) from about 0.05 to about 1.0 part per part of said soap of an alkali metal, ammonium, or mono-, di-, and triethanolamine salt of an ester of an alpha sulfonated fatty acid in which said ester contains from about 15 to about 25 carbon atoms as hereinafter more fully described; (3) from about 0.05 to about 0.30 parts per part of (1) plus (2) but not more than about 15% of fatty acid having from about 8 to about 20 carbon atoms; (4) from 0% to about 12% of water; (5) from about 2% to about 16% of a mixture of NaCl and KCl with the ratio of NaClzKCl between 1:3 and 3:1. All percentages referred to hereinbefore are by weight of the bar unless otherwise stated. Filler materials, minor additives and inert ingredients, if desired, can make up any balance.
It will be noted that there are three principal components in the bars of this invention: soap, the salt of an ester of an alpha sulfonated fatty acid, and fatty acid, as will hereinafter be described in detail. These components are the essential ingredients of the detergent bar disclosed in the copending application Serial No. 191,312 of Milton H. Hendricks, filed concurrently herewith. Each of these components is essential to the proper performance of this bar. The soap contributes low cost, good feel, good appearance, and a major detergency effect. However, soap also produces curd when used in hard water. The salt of the ester of an alpha sulfonated fatty acid markedly reduces the formation of soap curd in hard water. However, the addition of this ester to "Ice a soap bar results in a poorer lathering bar. It has been discovered that the addition of fatty acid to the salt of the ester of an alpha sulfonated fattty acid builds the lather of that ester to a surprising extent. The result of this unique effect is that when both the ester and the fatty acid are added to a soap bar, there is no appreciable loss of lathering to olfset the advantage of reduced soap curd formation. Lathering is improved by adding this mixture of fatty acid and ester to a soap bar.
In addition to the three major components of the bar there is also a specific mixture of NaCl and KCl present. It is with this mixture that this invention is primarily concerned and which comprises an improvement on the detergent bar of the copending application of Milton H. Hendricks. It has been discovered that mixtures of NaCl and KCl between ratios of NaClzKCl of from about 1:3 to about 3:1 impart an appearance of luster to the bars of this invention which is not provided by the use of either NaCl or KCl alone, or mixtures outside the ratio of NaClzKCl of from about 3:1 to about 1:3.
Although it is not desired to be bound by theory, it is believed that the dullness which is associated with the pure NaCl or KCl salts is caused by a thin layer of crystals forming on the surface of the bar. It is believed that the amount of salt crystals on the surfaces of the bars of this invention is greatly reduced over the amount of salt crystals on the surfaces of bars containing pure salts or salt ratios outside the about 1:3 to about 3:1
A measure of the amount of salt crystals in a thin layer on the surface of a bar is the extent to which visible crystals form when the bar is stored for long periods of time. The bars of this invention do not readily form visible crystals, upon prolonged storage, which in itself is desirable. This characteristic permits the inclusion of relatively high levels of salt which in turn decreases the amount of smear formed.
The choice of ratio of KCl:NaCl within the range of about 3 :1 to about 1:3 is made based upon several criteria including lustre, amount of smear, and recovery of smear. The lustre is at a maximum with a 1:1 ratio of KCl:NaC1; smear is at a minimum with maximum amounts of NaCl; and the recovery of smear is best with maximum amounts of KCl. The KClzNaCl component of the bar should be present in an amount of from about 2% to about 16% The preferred level of the KCl:NaCl component is from about 6% to about 10%.
The sodium and potassium soaps which are used in formulating these bars are the soaps of higher fatty acids. Although a range of specific chain lengths is given, it will be understood that the use of mixtures of these acids derived from natural sources is usual in soap preparation. When the term coconut 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%C8, 7%C 48% C12, 17%C 9%C 2%C 7%-oleic, and 2%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 approximate carbon chain length distribution of: 2.5 %-C 28% C 23%-C 2%palmitoleic, 41.5%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 sufficiently low content of unsaturates to have satisfactory keeping qualities without further treat- 7 ment. As is customary, however, the tallow fatty acids are hydrogenated to reduce unsaturation, particularly the poly unsaturated fatty acid content of this fatty acid mixture listed above to improve keeping qualities and smear. The soap will normally be no more than about 20% by weight potassium soap since the presence of potassium soap will tend to make the bars softer.
A bar containing less than about 40% by weight of soap is undesirable since below this amount lathering becomes poor and the bar smears objectionably while standing in the washstand. A bar containing more than about 80% by weight of soap cannot be used since provision must be made for sufficient alkali metal salt of an ester of an alpha sulfonated fatty acid, hereinafter referred to as ester; suflicient fatty acid; sufficient water; etc., to be incorporated in the bar to provide its overall desirable characteristics.
At least about 20% of the soap used in these bars and preferably more (up to 50% by weight of the bar) should be of the shorter chain fatty acids of from about 8 to 14 carbon atoms, preferably 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 (up to 80% by weight of the soap) has fatty acid chain lengths of from 14 to 20 carbon atoms, 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 tallow 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.
The addition of alkali metal, ammonium or substituted ammonium salt of the ester of an alpha sulfonated fatty acid, as hereinafter more fully described, modifies the behavior of the soap in that the deposition of the undesirable soap curd during use is markedly inhibited. At the same time, when the ester is used in combination with fatty acids, the bar produces a voluminous, small bubble, soap-like lather and retains its desirable soaplike feel and appearance. Furthermore, bars can be formulated which do not form cracks or surface irregularities during use and are not subject to undesirable smear or wastage during washstand use.
The ester used in the bars of this invention has the structure:
wherein X is selected from the group consisting of alkali metal, ammonium, monoethanolamine, diethanolamine and triethanolamine cations; R is an alkyl chain of from about six to about twenty carbon atoms (forming with the two carbon atoms a fatty acid group); and R is an alkyl chain, the sum of the carbon atoms in R and R being from about 13 to about 23 carbon atoms. Specific examples of this class of compounds include esters where R is selected from methyl, ethyl, propyl, butyl, hexyl and octyl groups and the fatty acid group (R plus the two carbon atoms in the structure above) is selected from lauric, myristic, palmitic, st'earic acids, and mixtures thereof.
As hereinbefore described, the ester should contain from 15 to 25 carbon atoms total. Esters with smaller numbers of carbon atoms than 15 tend to be harsh to the skin and esters with both larger and smaller numbers than the 15 to 25 range are not as effective at dispersing curd. The fatty acid portion of the ester should contain from about 8 to about 22 carbon atoms in order for the ester to be an effective curd dispersant.
There should be from about 0.05 to about 1.0 part ester per part soap in the bar. Less than the minimum amount of 0.05 part will not provide sufficient curd-dispersing properties in the bar and more than the maximum amount will adversely affect the physical characteristics of the bar such as smear.
The free fatty acids which are used in the practice of this invention vary in carbon chain length from about 8 to about 20 carbon atoms and in part act as plasticizers. It will be understood that the usual usage is of mixtures of fatty acids derived from natural sources. A preferred mixture of fatty acids is coconut oil fatty acids as herein before described. These acids preferably constitute a substantial portion (25% to 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 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 about 0.05 to about 0.30 part per part soap and ester in order to build the lather and improve its qualities. In no case should there be more than about 15% by weight of the bar of fatty acids. Either more or less fatty acid than this range of parts will not provide these good lather qualities to a satisfactory degree.
Plasticizers are present in order to make the bar sufiiciently plastic for processing and to make the bar firm yet free from undesirable cracking. As hereinbefore mentioned, the bar should contain from about 0% to about 12% by weight of the bar of water. Since both water and free fatty acids are plasticizers for the bar, high levels of free fatty acid are associated with low levels of water and vice versa. Particularly high levels of plasticizer provide a soft bar which is difficult to process and which may also be soft in use. Amounts of water above the range hereinbefore stated give bars which are too soft and mushy. The preferred moisture range is 2% to 10% 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 substantially altering the desirable bar characteristics of this invention.
Other minor 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 product of this invention is preferably prepared by forming a homogeneous aqueous mixture of the soap, ester, and inorganic salts, if present, and drying this mixture to granules or flakes containing 0% to 10% moisture. This granular material is then blended with the free fatty acid component and formed into a bar by milling, plodding, and stamping in conventional manners. The fatty acid can be added before drying of the aqueous mixture, if desired.
In the following example, which demonstrates advantages of this invention, the bars were formed by first making an intimate aqueous mixture of the soap and the ester in a crutcher, adding the inorganic salts, and roll drying to flakes of about 0.7% moisture. Then the flakes were amalgamated with the free fatty acid, optional ingredients were added as specified below, 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 bar in conventional equipment. The term coconut as referred to in these examples applied 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%oleic, and 2%linoleic (the first six fatty acids 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%, O -23%, palmitoleic-2%, oleic41.5%, and linoleic3% (the first three fatty acids listed are saturated). These fatty acids are hydrogenated so that the iodine value for the tallow fatty acids is lowered about 2 iodine value units for the soap and about 25 iodine value units for the fatty acids.
The symbols ASC-A as used herein refer to the sodium salt of the methyl ester of alpha sulfonated saturated fatty acids (approximately 50%-C 50%C fatty acids).
In the following compositions, numbered 1 through 5, part of the composition was held constant. In these bars, there was 4% H and 2% minor ingredients which included per-fume, dye, preservatives, and an opaci'fying and whitening agent.
The bars in this example were tested for smearing tendencies and crystallization tendencies. The tests were as follows:
The bar to be tested is placed in a shallow dish on Ms inch rods and 40 cc. of water is added to the dish. The bar is soaked for four hours and then the soft smear was removed with a knife blade, placed on a dish, dried, and weighed. The number of grams lost is the smear grade and the lower the grade, the better the bar.
When this same test is run to check the ability of the bar to recover from smeariness, the bar is soaked for two hours and then allowed to stand in the room air for four hours before removing the soft smear and completing the smear test as hereinbefore described.
Il.Crystallizatio-n The bars to be tested are placed on the shelf in a desiccator which has its lower level filled with water. The desiccator is closed and after 24 hours the bars are removed and dried. The bars are compared with a grade of +1 being better than the bar chosen as standard and +2 being much better than the standard. The bars are graded based upon visual inspection and the feel of the surface of the bars, paying particular attention to the luster and smoothness of the bar.
In the following example a bar containing NaCl as its only inorganic salt was taken as the standard.
EXAMPLE-PERCENT BY WEIGHT Composition 1 2 3 4 5 Sodium Coconut Soap 36 36 36 36 36 Sodium Tallow Soap--. 27 27 27 27 27 AS 13 13 13 13 13 Coconut Fatty Acid. 5 5 5 5 5 Tallow Fatty Acid 5 5 5 5 5 NaCl 8 6 4 2 0.5 (J 2 4 6 7. 5
4 hour soak- 4. 7 4. 9 5. 1 5. 9 6. 3 Recover 4. 4 3. 9 3. 8 3. 6 3.8 Crystallization 0 +1 +2 +1 +1 As can be seen from the compositions of the example, surface crystallization is at a minimum with a 1:1 mixture of NaClzKCl. This correlates quite well with the observed lustre of the bars which was also at a maximum with a 1:1 mixture of NaClzKCl. Ordinary smear is better with all NaCl and smear recovery is better with higher ratios of KClzNaCl so that from all considerations, mixtures of NaClzKCl between ratios of from about 1:3 to about 3:1 are best.
The bars of this example also lathered Well when used in the washstand and had other desirable physical characteristics, e.g., firmness and freedom from cracking.
When insoluble soap, starch, finely divided clay, and other coloring matter, perfume, and antimicrobial agents are added to the bars of this example in minor amounts, substantially equivalent results are obtained.
Other esters within the scope of the composition of the invention, e.g., the sodium and potassium salts of the hexyl, octyl, ethyl, and butyl esters of a-sulfonated palmitic acid; the potassium and sodium salts of the ethyl, butyl, hexyl, octyl, and decyl esters of a-sulfonated myristic acid; and the sodium and potassium salts of butyl, hexyl, octyl, and decyl esters of u-sulfonated stearic acid; and the sodium and potassium salts of butyl, hexyl, octyl, and decyl esters of u-sulfonated lauric acid can be substituted in the bar composition of the example with substantially equivalent results.
What is claimed is:
1. A detergent bar consisting essentially of an intimate admixture of:
(1) from about 40% to about by weight of soap having from 8 to 20 carbon atoms, at least 20% by weight of said soap having from about 8 to about 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 20% by weight of the said soap is potassium soap;
(2) from about 0.05 to about 1.0 part per part by weight of said soap of a salt of an ester of an alpha sulfonated fatty acid, said ester containing from about 15 to about 25 carbon atoms, said fatty acid containing from about 8 to about 22 carbon atoms, and the cation of said salt being selected from the group consisting of alkali metal, ammonium, monoethanolamine, diethanolamine, and triethanolamine cations;
(3) from about 0.05 to about 0.30 part per part by Weight of (1) plus (2), but not more than about 15% by weight of fatty acid having from 8 to 20 carbon atoms;
(4) from about 0% to about 12% by weight of water;
(5) from about 2% to about 16% by weight of a mixture of NaCl and KCl wherein the ratio of NaCl to KCl by weight is from about 1:3 to about 3:1 whereby superior luster and smear characteristics are achieved.
2. The detergent bar of claim 1 wherein the soap is a mixture of coconut oil soap and tallow soap and its cation is the sodium cation; the ester is the methyl ester of tallow fatty acids and its cation is the sodium cation, and the fatty acids are a mixture of coconut and tallow fatty acids.
3. The detergent bar of claim 2 wherein the ratio of NaCl to KCl is 1:3.
4. The detergent bar of claim 1 wherein the ratio of NaCl to KCl is 1:1.
References Cited by the Examiner UNITED STATES PATENTS 2,303,212 11/1942 Kise et al. 252-121 XR 2,894,912 7/1959 Geitz 252--117 XR 2,965,575 12/1960 Beaver et al. 252107 XR 3,043,778 7/1962 Kelly 2521 17 XR 3,076,766 2/1963 Anstett 252-11 FOREIGN PATENTS 845,376 8/1960 Great Britain.
JULIUS GREENWALD, Primary Examiner.