US 3850834 A
Soap compositions are provided capable of dispersing lime soaps formed by soap in hard water, and comprising a watersoluble fatty acid soap, an amount within the range from about 5 to about 15 percent by weight of free fatty acid having from about ten to about twenty-two carbon atoms, and an amount within the range from about 0.5 to about 3 percent by weight of an alkyl or alkyl phenol ether of an oxyalkylene glycol sulfate.
Description (OCR text may contain errors)
United States Patent [191 Hellsten et al.
[ Nov. 26, 1974 SOAP COMPOSITIONS CAPABLE OF DISPERSING LIME SOAPS  Inventors: Karl Martin Edvin Hellsten,
Odsmal; Anderson William Klingberg, Kallered, both of Sweden  Assignee: M och Domsjo Aktiebolag,
Ornskoldsvik, Sweden  Filed: July 19, 1971  Appl. No.: 163,858
 Foreign Application Priority Data July 2, 1970 Sweden 9169/70  US. Cl 252/117, 252/121, 252/132,
252/134, 252/551, 252/DIG. 16  Int. Cl. ..C1ld 1/14, Cl 1d 9/46, C1 1d 9/48  Field of Search 252/108, 121, 117, 532, 252/551  References Cited UNITED STATES PATENTS 2,588,264 3/1952 McDonald 252/121 2,758,977 8/1956 Knowles et a1. 252/153 3,232,879 2/1966 Lew 252/121 3,247,121 4/1966 Hendricks 252/117 3,324,183 6/1967 Priestley 252/548 X FOREIGN PATENTS OR APPLICATIONS 945,062 12/1963 Great Britain 252/121 1,213,333 11/1970 Great Britain 943,927 12/1963 Great Britain 252/121 OTHER PUBLICATIONS McCutcheons Detergents & Emulsifiers 1969 Annual, page 42, TP990. D4.
Triton Surface-Active Agents, bulletin of Rohm & Haas Co., 1955, Page 14.
The Action of Various Lime Soap Dispersants by N. Schonfeldt, J. Am. Oil Chemists Soc., 45, Pages 8082, February, 1968.
Primary Exanriner-Leon D. Rosdol Assistant Examiner-Dennis L. Albrecht  ABSTRACT Soap compositions are provided capable of dispersing lime soaps formed by soap in hard water, and comprising a watersoluble fatty acid soap, an amount within the range from about to about 15 percent by weight of free fatty acid having from about ten to about twenty-two carbon atoms, and anamount within the range from about 0.5 to about 3 percent by weight of an alkyl or alkyl phenol ether of an oxyalkylene glycol sulfate.
12 Claims, 1 Drawing Figure SOAP COMPOSITIONS CAPABLE OF DISPERSING LIME SOAPS One of the most conspicuous disadvantages of fatty acid soaps is their tendency in hard water to deposit lime soaps (the insoluble calcium salts of the soluble fatty acid soaps) on textiles and on the walls of washing vessels. The problem has heretofore been attached either by softening the water or by introducing surfactants capable of dispersing the lime soaps to form a stable colloidal system. The surfactants can either be combined with the soaps or added to the soap solutions. Thus, there are available soap compositions which when added to water will inhibit the formation of lime soap deposits, for example, as the ring in the bathtub. In the case of toilet soaps and soapbased detergents, it has been found most advantageous if the dispersing agent or surfactant is mixed directly into the soap composition. Many dispersing agents of this type have been suggested and used.
N. Schonfeldt, Journal of the American Oil Chemists Society 45 80-82 (1968), describes some of the most important dispersing agents which are useful in this way. Schonfeldt points out that when the soap is comprised of sodium oleate, a practically complete lime soap dispersion is obtained with the addition of from 2 to 5 percent by weight of nonylphenol or tallow fatty acid ethylene oxide adducts by weight of the soap. Another dispersing agent which has excellent lime soap dispersing properties, according to Schonfeldt, is sodium triethylene glycol lauryl ether sulfate, which is added in an amount of about 5 percent by weight. On the other hand, if sodium dodecyl benzene sulfonate or sodium lauryl sulfate is used, the amount must be at least equal to the amount of soap, in order to obtain a satisfactory lime soap dispersion.
Schonfeldt carried out his experiments at 95C. with sodium oleate as the soap. However, lime soap dispersion at lower temperatures of the order of 40C. is much more difficult to achieve, and if a normal satu rated fatty acid toilet soap composition is used, based on (for example) about 20 percent by weight sodium soaps of coconut fatty acids and 80 percent by weight sodium soaps of tallow fatty acids, at 40C. percent by weight of the soap of the ethylene oxide adducts or 5 percent by weight of the soap of sodium lauryl ether sulfate are required, in order to obtain a satisfactory lime soap dispersion.
British Pat. No. 945,062 describes toilet soap compositions containing more than 5 percent alkyl ether sul fates. However, the use of large quantities of synthetic surfactants, such as nonionic surfactants or alkyl ether sulfates, results in an unfavorable effect on the physical properties of the soap, particularly its plasticity, and its tendency to swell when in contact with moisture. The surfactant considerably reduces plasticity, resulting in an increased tendency towards crack formation, and the composition also has an increased tendency to swell when in contact with moisture. In order to retain the normal physical properties of the soap, so that it can be plodded in conventional soap plodding equipment and retain its stability in the presence of water, it is important to keep the amount of surfactant at 3 percent or less. However, it has not been possible heretofore to provide a toilet soap composition having a good lime soap dispersing ability and at the same time such a small amount of admixed surfactant or dispersing agent.
In soap powders, an admixture of as muchas 5 percent of a surfactant or dispersing agent in the form of a nonionic surfactant, such as a polyoxyalkylene glycol ether, results in the powders becoming soft and sticky, so that they are difficult to process during manufacture, and also tend to become lumpy and form large agglomerates in storage. Therefore, in soap powders a small amount of nonionic surfactantis generally used, together with a sodium tripolyphosphate or other sodium polyphosphate salt for lime soap dispersion. An addition of from 4 to 5 percent of an anionic surfactant as the dispersing agent, for example, an alkyl ether sulfate, generally causes no change in the physical characteristics of the soap powder, but results in an undesirable stabilization of the lather volume in the washing solution, which is particularly disadvantageous when the composition is used for washing in automatic washing machines. Thus, in this case also it is important to keep the addition of surfactant or dispersing agent as low as possible.
It is also known that a satisfactory dispersion of lime soaps in hard water can be obtained if to the soap product there is added at least 20 percent by weight of free fatty acids, and these also can be used in toilet soaps. However, the free fatty acids show a pronounced tendency to become rancid with time, and therefore oxidation inhibitors have to be added, which increase the cost of the product in an amount proportional to the amount of fatty acid. Moreover, a high content of free fatty acids also increases the cost. Therefore, it is important to keep the free fatty acid content as low as possible.
In accordance with the invention, soap compositions are provided based on a water-soluble fatty acid soap, comprising an amount within the range from about 5 to about 15 percent by weight of the soap of free fatty acid having from about ten to about twenty-two carbon atoms, and an amount within the range from about 0.5 to about 3 percent by weight of the soap of an alkyl or alkyl phenol oxyalkylene ether sulfate in which the alkyl group has from about ten to about twenty carbon atoms and the alkyl phenol has an alkyl chain having from about eight to about fifteen carbon atoms and the oxyalkylene unit is derived from ethylene oxide, propylene oxide, butylene oxide or mixtures thereof. Such compositions give a substantially complete dispersion of lime soaps at temperatures as low as 40C. and a soap concentration of as low as 1 gram per liter of water having a hardness of 20 These compositions also have substantially the same physical properties as ordinary soap with respect to plasticity and swellability in the presence of moisture.
The water-soluble soaps which can be used in the soap compositions-of the invention are the alkali metal soaps, such as sodium, potassium and lithium soaps, as well as the ammonium and organic amine soaps of the saturated and unsaturated fatty acids having from about ten to about twenty-two carbon atoms. The organic amine can be of any of those noted below.
The saturated fatty acids are preferred, since they are more stable, and are not as easily oxidized as the unsaturated acids. Examples of fatty acids include capric acid, undecylic acid, lauric acid, tridecoic acid, myristic acid, palmitic acid, margaric acid, stearic acid, arachidic acid, oleic acid, linoleic acid, linolenic acid, ri-
cinoleic acid, myristoleic acid, palmitoleic acid, erucic acid and behenic acid, as well as the fatty acid mixtures derived from natural fats and oils, such as tallow fatty acids, linseed oil fatty acids, coconut oil fatty acids, fish oil fatty acids, palm kernel oil fatty acids, cottonseed oil fatty acids, hydrogenated soya bean oil fatty acids, corn oil fatty acids, lard fatty acids, sesame oil fatty acids, peanut oil fatty acids, safflower oil fatty acids, sunflower oil fatty acids, Whale oil fatty acids and sperm oil fatty acids.
The free fatty acid also used as a component of the soap compositions can be any of the acids named above, or fatty acid mixtures derived from natural fats and oils, as indicated above. The free fatty acid can be of the same type as the fatty acids present as the alkali metal or ammonium or organic amine salts, or a different mixture of fatty acids can be used, as desired.
The alkyl or alkyl phenol oxyalkylene ether sulfates in accordance with the invention have the formula:
R, (OR OSO M wherein:
R is an alkyl group having from about to about 20 carbon atoms or an alkyl phenol group having from 1 to 3 alkyl groups, at least one having from about eight to about carbon atoms; and the others having from one to 15 carbon atoms.
R; is an alkylene oxide residue derived from ethylene oxide, l,2 or l,3propylene oxide, or l,2, 2,3, 1,3, or l,4-butylene oxide, or mixtures thereof.
M is an alkali metal, such as sodium, potassium or lithium, or ammonium, or an organic amine, particularly a strongly basic aliphatic or hydroxyaliphatic amine, such as butylamine, octylamine, hexylamine, diethylamine, ethylbutyl amine, tributylamine, triethylamine, tripropylamine, monoethanolamine, diethanolamine, triethanolamine, or dipropylamine. The organic amine has from about three to about twelve carbon atoms and from about one to about three hydroxyl groups.-
is a number from l to 10, and represents the average number of alkylene oxide units (oxyalkylene units). It will be understood that there will be present in admixture species having values both higher and lower than the average value for A preferred class of oxyalkylene units have the formula:
O(CHCHO)m 1| 5 in which has a value greater than 0, up to about 10, and preferably is within the range from about 1 to about 5, and denotes the average number of oxyalkylene units in the chain.
The oxyalkylene base (CHCIIO)m ll, 1%. can be, for example, oxy-l,2-propylene; oxyethylene; oxy-l,2-butylene; oxy-2,3-butylene; and block copolymers of a polyoxyethylene chain and a polymerized alkylene oxide of at least three carbon atoms, preferably 1,2-propylene oxide. Thus, the alkylene oxide condensate may consist entirely of one alkylene oxide, or of a condensed mixture of two or more alkylene oxides, such as a mixture of ethylene oxide and propylene oxide, in blocks, or heterogeneously distributed in the oxyalkylene chain.
These oxyalkylene ether sulfates are obtained by condensation of the corresponding alkylene oxide or mixture thereof with an aliphatic alcohol or alkyl phenol, the corresponding fatty alcohol and alkyl phenol adducts with a range of oxyalkylene units being obtained. The number of oxyalkylene units should be within the range from about 1 to about 10, as an average, and preferably an average of from 1 to 4 oxyalkylene units per fatty alcohol or alkyl phenol unit. The oxyalkylene monoether adducts are then sulfated, using sulfuric acid, chlorosulfonic acid, fuming sulfuric acid, sulfur trioxide or sulfaminic acid to form the corresponding sulfates. The sulfates are in the form of the alkali metal salts preferably, because they impart the best consistency to the soap composition. Exemplary organic compounds having an active hydrogen atom that can be employed to produce alkylene oxide adducts for the radical of the oxyalkylene sulfate esters (R, in the formula R (O-R are the primary alcohols such as octanol, decanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, eicosanol, docosanol, tetracosanol, straight or branched, primary or secondary OXO- alchols, i.e., alcohols prepared by the OXO process, having from 12 to 26 carbon atoms, such as the essentially straight chain alcohols produced from Fischer-Tropsch olefins by the OX0 process, and multi-branched chain alcohols produced from olefins having at least seven carbon atoms and two side chains, such as tripropylene, tetrapropylene, pentapropylene, diisobutylene and triisobutylene by the OXO process, mono-, di-, and trialkyl phenols, such as octyl phenol, isooctyl phenol, nonyl phenol, dodecyl phenol, dioctyl phenol, dinonyl phenol, didodecyl phenol, trioctyl phenol, trihexyl phenol, tridodecyl phenol, methyloctyl phenol, and ethylisononyl phenol, tri-primary, secondary, and tertiary butyl phenol, 3-methyl-4,6-dibutyl phenol, octadecyl phenol, di-octadecyl phenol, trioctadecyl phenol, mono-, di-, and tributyl cresol, mono-, di-, and trinonyl cresol.
of the ty sodium, potassium, ammonium and organic amine cetyl ether sulfates of the type sodium, potassium, ammonium and organic amine stearyl ether sulfates of the type sodium, potassium, ammonium and organic amine nonylphenol ether sulfates of the type sodium, potassium, ammonium and organic amine cetyl ether sulfates of the type The amount of free fatty acid is within the range from about 5 to about 15 percent, preferably from about 5 to about 12 percent, and still more preferably fror n.
about 6 to about percent, by weight of the soap. The amount of the alkyl or alkyl phenol oxyalkylene ether sulfate is within the range from about 0.5 to about 3 percent, preferably from about 0.5 to about 2.5 percent, by weight of the soap.
In addition to these ingredients, which are the essential ingredients, the soap composition of the invention can contain other components which are customary in soap compositions, such as inorganic and organic complex-forming agents, neutral builder salts, soilsuspending agents, optical brightening agents, coloring agents and pigments, and perfumes. Inorganic and organic complex-forming agents are added for improving the soil-removing power of the soap composition, particularly for heavily soiled articles. Optical brightening agents that may be used include stilbines, diaminostilbines, acylated cyanuric and triazalyl derivatives of stilbines, diphenyl derivatives, dibenzothiophene derivatives, aminocoumarone salts, derivatives of azotized amino-containing benzoazoles, benzthiazoles, and benzimidazoles. A number of such agents are disclosed in [1.8. Pat. No. 3,122,508.
The compositions of the invention can be formulated as solutions or slurries which are spray-dried, or as light-duty or heavy-duty concentrated detergent solutions or concentrates. The compositions can also be formed into granules, flakes, chips and powders, using Example 1 In a 100 ml graduated cylinder there was placed 20 ml of a 0.5 percent aqueous solution of a sodium base soap for toilet soap. The fatty acid composition of this soap was 20 percent by weight of coconut fatty acids and 80 percent by weight tallow fatty acids. Free fatty acids composed of 20 Weight per cent coconut fatty acids and 80 weight per cent tallow fatty acids were then dispersed in this soap solution. A series of such compositions were prepared, containing different amounts of free fatty acids based on the weight of the soap, as shown in the attached graph. Then, to these several compositions there were added amounts within the range from 0.5 to 3 percent by weight of sodium ,cetyl stearyl diethylene glycol ether sulfate, and the graduated cylinder filled with distilled water to 80 ml. Finally, 20 ml of water was added, to which had been added calcium chloride to a hardness of 100 of hardness. These solutions were then subjected to a standardized mixing procedure, in the course of which the cylinder was closed, turned upside down 5 times for mixing, and then held in a thermostat bath at C. for 1 hour. Ten milliliters of the resulting solution were removed with a pipette, the point of which was held 1 centimeter above the bottom of the cylinder. This quantity of solution was titrated with 0.01 molar BC], with chrome cresol green as an indicator. The consumed quantity of hydrogen chloride is directly proportional to the quantity of dispersed lime soap. Nondispersed lime soap rises to the surface, and forms a layer at the surface of the liquid. The results are shown in Table I which follows:
TABLE I by Weight of Soap Base Fatty Acids Dispersed Sodium Cetyl Stearyl 20% Coconut Oil Amount of Lime Experi- Diethylenc Glycol Tallow Soap in of ment Ether Sulfate Fatty Acids Total Amount l 0 0 30 2 0 5 37 3 0 7.5 53 4 0 I0 82 5 0 I5 6 0 20 7 0.5 0 40 8 0.5 5 50 9 0.5 I0 100 10 1.0 0 66 l l 1.0 5 66 l2 1.0 9.5 I00 l3 1.5 0 67.5 14 1.5 5 67.5 15 1.5 9 I00 I6 2 0 84 I7 2 5 82 I8 2 7.5 92 I9 2 9 l00 20 3 0 95 2| 3 5 97.5
conventional techniques, or plodded to form bars or cakes.
The following Examples in the opinion of the inventors represent preferred embodiments of the invention.
The amount of dispersed lime soap was then graphed as the ordinate against the content of free fatty acids as abscissa for the series of different contents of the sodium cetyl stearyl diethylene glycol ether sulfate. A family of curves was obtained, with the content of sodium cetyl stearyl diethylene glycol ether sulfate for each curve indicated on the curve.
The results make it clear that a content of free fatty acids of about 8 percent at a content of about 0.5 to 3 percent of sodium cetyl stearyl diethylene glycol ether sulfate gave a practically complete dispersion of the lime soap. At lower contents of free fatty acids, the results were less satisfactory.
Example 2 Example 1 was repeated, substituting lauric acid as the free fatty acid, and sodium lauryl triethylene glycol ether sulfate as the alkyl oxyalkylene ether sulfate. All other compositions and test conditions were as set forth in Example 1. The following results were obtained:
TABLE II by Weight of Soap Base Dispersed Sodium Lauryl Amount of Lime Experi Triethylene Glycol Lauric Soap in of ment Ether Sulfate Acid Total Amount The above results show that a mixture of the sodium lauryl triethylene glycol ether sulfate and lauric acid is more efficient as the lime soap dispersing agent than either the sodium lauryl triethylene glycol ether sulfate or the lauric acid alone.
Example 3 This example illustrates the lime soap dispersing capability of various anionic surfactants in combination with free fatty acid. The soap and the free fatty acid were as in Example 1, while the amounts of 7 percent free fatty acid and 3 percent anionic surfactant by weight of the soap were used in all experiments. In other respects, the experiments were carried out as in Example 1. The following results were obtained:
TABLE III Dispersed Amount glycol ether sulfate The data show that the alkyl oxyalkylene ether sulfates of the invention, Experiments 7, 8 and 9, in combination with free fatty acid show a conspicuous ability to disperse lime soap, while the other types of anionic surfactants, Experiments 2 to 6, did not influence the dispersion of lime soaps to any noticeable extent, either in a positive or in a negative direction.
Example 4 To a soap solution according to Example 1 was added 5 percent of tallow fatty acids and various surfactants in an amount of 0.5 percent. In other respects, the experiments were carried out as in Example 1. The following results were obtained:
The data show that the alkyl oxyalkylene ether sulfates in accordance with the invention, Experiments 2, 3 and 4, give excellent results in combinations with free fatty acid, and are clearly superior to the sulfates, sulfonates and nonionic surfactants, Experiments 5, 6 and 7, as lime soap dispersing agents.
Having regard to the foregoing disclosure, the following is claimed as the inventive and patentable embodiments thereof:
1. A solid soap composition in bar or cake form capable of substantially completely dispersing lime soap at temperatures as low as 40C. and a soap concentration of as low as 1 gram per liter in water having a hardness of 20, consisting essentially of a water-soluble fatty acid soap selected from the group consisting of the alkali metal soaps, ammonium soaps, and organic amine soaps of the saturated and unsaturated fatty acids having from about 10 to about 22 carbon atoms, an amount within the range from about 5 to about 15 percent by weight of the soap of free fatty acid having from about 10 to about 22 carbonatoms, and an amount within the range from about 0.5 to about 3 percent by weight of the soap of an alkyl or alkyl phenol oxyalkylene ether sulfate having the formula R, (0R 050 M in which R is selected from the group consisting of alkyl groups having from about 10 to about 20 carbon atoms and alkyl phenol groups having from one to three alkyl groups at least one having from about eight to about 15 carbon atoms and the others having from one to 15 carbon atoms; R is an oxyalkylene unit selected from the group consisting of oxyethylene oxypropylene and oxybutylene units and mixtures thereof, and contains an average of from one to about ten oxyalkylene groups, M is selected from the group consisting of alkali metals, ammonium, and organic amines having from about three to about twelve carbon atoms and from none to about three hydroxyl groups, and n is a number from 1 to 10.
2. A solid soap composition according to claim 1 in which the fatty acid is a fatty acid mixture derived from natural fats and oils.
3. A solid soap composition according to claim 2 in which the fatty acid mixture is selected from the group consisting of tallow fatty acids and coconut oil fatty acids.
4. A solid soap composition according to claim 1 in which free fatty acid is a fatty acid mixture derived from natural fats and oils.
5. A solid soap composition according to claim 1 in which the free fatty acid is selected from the group consisting of lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid and linoleic acid.
6. A solid composition according to claim 1 in which the alkylene units have the formula:
in which m is a number from 1 to about 10, and denotes the average number of oxyalkylene units in the chain; and R and R are selected from hydrogen and methyl.
7. A solid soap composition according to claim 6 in which one of R and R is hydrogen and the other is hydrogen or methyl and is a number from 1 to 4.
8. A solid soap composition according to claim 1 in which the amount of free fattyracid is from 5 to 12 per cent by weight of the soap and the amount of alkyl or alkyl phenol oxyalkylene ether sulfate is from 0.5 to 2.5 percent.
9. A solid soap composition according to claim 1 in which alkyl oxyalkylene ether sulfate is a cetyl stearyl ether adduct with two mols of ethylene oxide and the fatty acid both as water-soluble soapand as free fatty acid is a mixture of tallow fatty acids and coconut oil fatty acids.
10. A solid soap composition according to claim 1 in which the alkyl oxyalkylene ether sulfate is lauryl ether adduct with three mols of ethylene oxide, and the free fatty acid is lauric acid.
11. A solid soap composition according to claim 1 in which the alkyl oxyalkylene ether sulfate is myristyl ether adduct with two mols of ethylene oxide and the free fatty acid is a mixture of tallow fatty acids and coconut oil fatty acids.
12. A solid soap composition according to claim 1 in which the alkyl phenol oxyalkylene ether sulfate is do decyl phenol ether adduct with four mols of ethylene oxide and the free fatty acid is tallow fatty acids.