US2092913A - Detergent composition - Google Patents

Description

252. COMPOSITIONS,

Patented Sept. 14, 1937 UNITED STATES PATENT OFFICE DETERGENT COMPOSITION Augustus H. Fiske,

Warren, R. 1., assignor to Rumford Chemical Works, Rumford, R. I.

Claims.

My invention relates to improved detergents of many different kinds but has especial relation to detergents containing a compound of tetraphosphoric acid and more particularly an alkali metal salt of tetraphosphoric acid or admixture therewith, and processes of applying the same.

The object of my invention is to provide a detergent or cleanser, as, for example, a soap, containing in intimate admixture therewith, a compound of tetraphosphoric acid or an alkali metal salt of tetraphosphoric acid, so as to obtain an effective softening effect upon water in which the detergent is used, as well as the process of applying the same. A further object is to dissolve the combinations of the soap, or other detergent, with the substances producing the hardness" of water, loosen the dirt by dissolving the alkali earth compounds present, improve the sudsing value of the soap, as well as to regenerate any of the soap that is combined with the alkali earth derivatives present.

Practically all natural waters contain salts of the alkali earth metals, as, for example, calcium and magnesium in solution in small quantities, thus producing the property known as hardness". This has an important bearing in washing operations because the alkali earth compounds tend to form an insoluble precipitate with the fatty acid radicals of the soap, resulting in a waste of the soap by withdrawing it from a cleansing action. Also, the insoluble soaps thus formed produce a coating on the object or textile being cleansed, which is not easy to remove. Soap has no sudsing power with hard water until all the hardness has been taken care of by the soap and it is only the soap in excess of that amount which provides the sudsing power. Therefore, the soap which has combined with the compounds producing hardness is wasted. It is well recognized that the sudsing power of soap is the measure of its cleansing power, therefore the presence of a material which will increase this power, by softening the water or taking care of the alkali earth basic radicals in the water or regenerating the soap from its combination with the compounds producing hardness, as in accordance with my invention, has an important value in the saving of soap.

In accordance with my invention I provide in the presence of the detergent a water soluble compound of tetraphosphoric acid, preferably a water soluble salt of the tetraphosphoric acid, as, for example, sodium, potassium or ammonium salts thereof, as well as an effective process of utilizing the same.

The tetraphosphoric acid to which I refer was discovered by Fleitman and Henneberg in 1848 and has the following constitution, as set forth by Roscoe and Schorlemmer in their Treatise on Chemistry, Vol. I, MacMillan & Co., Ltd., 1905, page 656:

Tetraphosphoric Acid PO-OH This is not to be confused with the so-called fr. *5"; Xfie.

tetraphosphate fertilizer discovered by Stoppani in 1911, and which was made by heating the carbonates of sodium, magnesium, calcium and sulphate of sodium with natural mineral phosphates to a temperature of about 600 0., a process developed to make the mineral phosphate merely available as a plant food. The product made by Stoppani was doubtless called tetraphosphate because of the fact that four ingredients were used in its preparation, in addition to the mineral phosphate present, and the name applied thereto was evidently merely a trade term, his product being understood to be a double orthophosphate of calcium and sodium. The tetraphosphates produced by Fleitman and Henneberg have the general formula R6P4013, where R signified the base, and were made by them by fusing together pyrophosphates and metaphosphates, also orthophosphates and metaphosphates. Also, sodium tetraphosphate is referred to in the British patent to Patten, No. 8,197 of 1901, as being made by a reaction between sodium bicarbonate and acid sodium pyrophosphate. Also, according to Chem. Ztg., Rakuzen 8; Arseneev, 1923, pages 47, 195, prepared tetraphosphoric acid, HsP4O13, and this acid prepared by them and its water-soluble compounds and its salts are the ones referred to in the compounds here. Wherever the word tetraphosphate or "tetraphosphoric acid occurs herein it will be understood that it is the one referred to by Rakuzen and Arseneev, Fleitman and Henneberg and Roscoe and Schorlemmer as already mentioned.

The soaps which I may use, furthermore, may be comprised of one or more compounds of a fatty acid with an alkali metal with or without the presence of excess free alkali and other ingredients, such as borax, ammonium compounds, orthophosphates, soda ash, rosin, etc., in any desired proportions.

I have found, for instance, that a mixture of a water-soluble compound of tetraphosphoric acid, and particularly a tetraphosphate such, for instance, as sodium tetraphosphate, with a soap, as, for example, a sodium soap, or a sodium soap powder, or any detergent mixture, depending upon the presence of a sodium soap, for example, will provide a more efficient washing than the soap or detergent without the presence'of the tetraphosphoric acid compound. Furthermore, while the softening of the water beforehand with the tetraphosphoric acid compound is beneficial, even when adding the soap thereto afterwards, this does not give as satisfactory sudsing or cleansing results, as in the case of the intimate admixture of the soap or detergent with the tetraphosphoric acid compounds at the time when they are added to the water. If the water is treated with the tetraphosphoric acid compound in a sufficient amount to soften the hardness thereof and then used, with soap subsequently added for washing, the bubbles formed are large and coarse. If, however, the soap is intimately mixed with the tetraphosphoric acid compound and then added to the water, the suds are found to be of a fine texture and much more dense under the same sudsing conditions. In the former instance it is found that the lather is much thinner, whereas in the latter case the lather has a velvet-like feel not present in the former instance. In the latter instance a more superior sudsing power is also attained. The said mixed materials may be in their dry form.

My theory of this action is that a certain effective concentration of a common ion in water is what causes the soap to give satisfactory suds. This is based on the fact that the table used in the well-known standard method for determining the hardness of water admits that the consumption of the standard soap solution up to 0.7 cc. in the titration is still considered zero hardness in reading the results. In other words, since the standard charge of water in the method is cc., it requires 0.7 cc. of added standard soap solution to give sufficient ionic concentration of of undissociated soap to give the solution sudsing properties. The directions for this method are given in Standard Methods of Chemical Analysis by Wilfred W. Scott, fourth edition, 1934, seventh printing, Vol. II, page 1439. I have confirmed this theory in the following way. I determined the hardness of a natural water by the standard method using a 50 cc. charge and titrating with a standard soap solution. This titration took 2.4 cc. of the standard solution which indicated by the standard table of equivalents a hardness of 24.7 degrees. lar 50 cc. charge of the same water and added 5 cc. of a 1% solution of sodium chloride, thus adding a common ion in the form of a well dissociated salt. Then on titrating the charge once more I obtained 19.5 of hardness as my result. Thus we see that the addition of the common ion (sodium) caused the sudsing to take place with less soap consumption giving an erroneous result to the analysis as no change in the calcium car- I then took a simi-- bonate hardness had been made between the two samples of water. It is also my theory that the sodium ion of the tetraphosphates, being in direct contact with the soap as it is dissolved, will give sufficient concentration more quickly to keep the soap in undissociated condition, than if it is dispersed throughout the solution as in a water just softened by the tetraphosphate. Thus we see that having the sodium tetraphosphate directly dispersed throughout the body of the soap, and having the material dissolved simultaneously with the soap, we have a greater concentration of sodium ions about the soap as it dissolves and, therefore, a quicker and more concentrated sudsing power. This theory will account for the peculiar action of the sodium ion of the tetraphosphate but in addition we have the tetraphosphate ion and it is this ion which at the same time protects the fatty acid radical from the action of the calcium or magnesium compound hardness of the water. Being simultaneously dissolved with the soap it is present in concentrated form with the soap as they both dissolve and, therefore, the tetraphosphate keeps the calcium or magnesium ions from combining with the fatty radical of the soap by combining with the calcium ion itself to form a more complex radical, which, while it may restrict the sudsing power of the solution to some extent in an excess of soap, yet, especially in the lower concentrations, will assist the sudsing power. This complex radical is soluble in water.

A tetraphosphate has the power of softening water, as set forth in the copending applications on the utilization of tetraphosphates and their methods of manufacture in which I am a joint inventor with Charles S. Bryan, as follows: Process for softening water and dissolving calcium salts, Ser. No. 756,459, filed Dec. '7, 1934 Patent No. 2,059,570, granted November 3, 1936, Process of making tetraphosphates and product thereof,

Ser. No. 756,457, filed Dec. 7, 1934, Patent No.

2,031,827, granted February 25, 1936, Process of producing tetraphosphates, Ser. No. 2,921, filed Jan. 22, 1935 Patent No. 2,019,665, granted November 5, 1935 and Method of obtaining tetraphosphates, Ser. No. 2,922, filed Jan. 22, 1935 Patent No. 2,019,666, granted November 5, 1935.

Thereformpersing the tetraphosphate throughout the soap or detergent there is pro duced a sudsing action due to the concentration of the sodium ion at the time of the solution of the soap and also the softening power of the tetraphosphate ion, in that it combines with the calcium or magnesium to remove it from the sphere of influence of the fatty acid radical of the soap. These effects contribute beneficially to each other.

In order to show the dissociation of the soap more clearly I will give the following balanced reaction as illustrative:

The compound represented by the chemical radical CH3(CH2)14CO2 is the radical of palmitic acid and is given only as an illustrative example of an ingredient in the soap. Now if we add some sodium tetraphosphate to the solution in concentrated form, as the soap dissolves with the dissolving of the tetraphosphate we first have the tetraphosphate dissociation as follows:

+ N84P40 3 etc.

252. COMPOSITIONS,

llllll as the ionic condition. According to my invention the concentrations of the tetraphosphate while in contact with the soap as it dissolves, will tend to remain high and thus maintain a high concentration of the Na+ ions in the neighborhood of the soap as it is gradually consumed. Thus with a high concentration of Na+ ions about the soap we have a tendency of the Na+ ions to force the reaction of the dissociation of the soap toward the left and so with this shift of the equilibrium I have a greater concentration of undissociated sodium fatty acid salt (or soap) formed to bring the conditions to a balance once more. Likewise this tends to make the soap give a sudsing value at a lower concentration as this sudsing value depends on the concentration of undissociated soap and not on the total concentration of soap in the solution in the dilute conditions referred to. When the soap is dissociated the addition of more Na+ ions to the right hand side of the equilibrium representing the dissociation of the soap, tends to cause more undissociated soap to form on the left hand side of the equation until equilibrium is once more obtained.

As natural waters vary in their hardness, the soap or detergent which contains a softener for the natural hardness should vary its proportional quantity of softener in a similar manner. I have found that it requires, in practical work, approximately half as much tetraphosphate by weight as there is hardness by weight, if I calculate the hardness in terms of calcium carbonate, to take care of the hardness. Therefore, it can be seen that a gallon of water at 100 of hardness (100 parts per million of equivalent calcium carbonate) contains 6 grains of calcium carbonate and I may calculate about 3 grains of tetraphosphate for the equivalent soap to be used in this gallon to yield an efiective softness. I have found that it takes about 15 grains of soap to a gallon of water for ordinary washing, so that in this instance it would be correct to use three grains of the tetraphosphate to every 15 grains of soap or 20% of the weight of the soap. However, it is found that the proportions can be very widely varied in actual cleansing operations. For instance, it is found that as much as 25 grains of soap per gallon of water may be used and sometimes the best results are obtained with three times to five times the amount of the calcium carbonate equivalent hardness of tetraphosphate. This would make it necessary to vary the percentage of my tetraphosphate in my detergent mixture at least from 10% to of the mixture. For this reason I do not confine myself to any particular proportion of my tetraphosphate to any particular quantity of soap or detergent but the quantity may be varied to suit the market or locality where the soap is to be used and on a basis of the hardness contained in the water of that locality.

According to the U. S. Geological Survey the hardness of water is expressed in terms based on parts per million and one part per million of equivalent calcium carbonate is expressed by them as a degree of hardness. They classify the natural waters of the United States as follows:

of hardness or under is soft 55 to 100 is moderately soft 100 to 200 is moderately hard 200 to 500 is excessively hard.

Therefore, for soft or moderately soft waters I would use up to 20% of my tetraphosphate and for harder waters proportionately larger amounts should be used. I have found, however, in certain sections of the country where the water contains under 20 of hardness that 5% of tetraphosphate of the soap or even less may be used effectively to soften the water for the soap.

Of course, instead of the sodium tetraphosphates above mentioned, a potassium tetraphosphate may be used, and instead of a sodium soap, a potassium soap may be used, although when using a potassium soap it 'is desirable to use a potassium tetraphosphate therewith. Also, a liquid soap will generally contain both sodium and potassium bases and tetraphosphates thereof.

I have found, furthermore, that any of these compounds of tetraphosphoric acid will dissolve calcium or magnesium compounds from any constituent of the dirt or contaminating material which is to be removed in the process of cleaning. Thus the tetraphosphate will dissolve the calcium compound instead of allowing it to be combined with the soap and so destroy and consume the soap. Also, the tetraphosphate causes the calcium compound to remain soluble and prevents it from interfering with the action of the soap. At the same time, in the process of cleaning, if I dissolve out one constituent of a material, as, for instance, the first to be removed in a cleansing operation, then the other portions of the dirt will obviously be loosened or set free by this partial solvent action.

Furthermore, when the tetraphosphate loosens the dirt by dissolving from it its calcium constituent, then it is important to have the soap in admixture with it in sufficient concentration to remove the dirt from the material which it is desired to clean. Thus, the tetraphosphate in the detergent not only acts as a water softener and in this way a soap saver, but also as an important auxiliary to the detergent, as it is a dirt loosener itself. There is another phase of the action of my invention which is important from the economy standpoint. If, for example, common soap is used to wash an object or fabric, as the calcium compounds or similar compounds are loosened and dissolved by the soap they combine with the fatty acid radical present in the soap and on which the soap depends to alarge extent for its cleansing action. Thus, the cleansing power of the soap is gradually consumed by the dirt during the process of cleansing. If the soap contains an intimate mixture of the tetraphosphoric acid compound in soluble form this material tends to dissolve and combine with the calcium and other compounds which have combined with the fatty acid radical of the soap and reduced its cleansing power. The act of combining the tetraphosphate with these dirt-forming bases sets free the fatty radical of the soap and when thus regenerated it is once more ready to act as a cleanser in its rejuvenated form. Thus, the soap is made to be more efficient and far-reaching in its action. A great economy is thus effected in the consumption of soap in this phase of the cleansing action.

I of course do not confine myself to ordinary soaps, in my invention, as the same extends to all varieties of detergents and cleansers, a partial list of which is as follows: Laundry soaps, hard soaps, naphtha soaps, soaps containing oils as 5 solvents, soaps containing abrasives, liquid soaps, toilet soaps, tooth powders or pastes, floating soaps, salt water soaps, alkaline soaps, ammoniacal soaps, mechanics soaps, disinfecting soaps, industrial soaps, milled soaps, medicinal soaps, shampoo soaps, automobile soaps, surgical soaps, textile soaps, soap powders, soap flakes and soap chips; soap mixtures with sodium carbonate with or without sodium sesquicarbonate, with or without caustic soda, with or without trisodium phosphate, with or without sodium silicates, with or without metaborates and with or without borates; also soap pastes containing any of the usual ingredients such as abrasives, oils and water or any of the previously mentioned materials; also cleaning mixtures which may or may not contain soaps but may contain any of the above mentioned materials; also acid cl e ansers, g s, for instance, oxalic acid, M or without acid so- Mdium sulphate which are often used as cleansers; 2 also waterstiunong of sodium or potassium bisulphite or hypochlorite used by brewers in cleaning, purifying and sterilizing vats and fermentation rooms, or by dairymen for removing calcium casein compounds and sterlizing, for which, if desired, dry mixtures of bisulphite or hypochlorite and a water soluble compound of tetraphosphoric acid or a tetraphosphate may be utilized; any detergent containing an alkali metal salt of sulphonated alkyls of the general formula R o 0 S\ o o for example, where R represents a carbon radical 2,092,913.-Augustus H. Fiske,

dated September 14, 1937.

of from 10 to 18 carbon atoms, and for Na other alkali metals may be substituted; also all other detergents, cleaners and soap substitutes or materials which are used in the place of soaps.

In the case of any of the above detergents, soaps or admixtures therewith, and containing a water soluble tetraphosphoric acid compound, as, for instance, an alkali metal salt of tetraphosphoric acid, it is to be understood that any proportions whatever of these various constituents may be utilized in these admixtures, as desired.

While I have described my invention above in detail I wish it to be understood that many changes may be made therein without departing from the spirit of the same.

I claim:

1. A detergent composition containing a detergent having a cleansing action and an alkali metal salt of tetraphosphoric acid.

2. A water-soluble soap composition containing a soap and an alkali metal salt of tetraphosphoric acid.

3. A washing liquid containing water and a water-soluble soap composition containing a soap and an alkali metal salt of tetraphosphoric acid.

4. A detergent composition containing a sodium salt of a sulphonated alkyl of the formula where R is a radical of from 10 to 18 carbon atoms and a sodium salt of tetraphosphoric acid.

5. A detergent composition containing a hypochlorite of an alkali metal and an alkali metal salt of tetraphosphoric acid.

AUGUSTUS H. FISKE.

Warren, I. Dn'rERGENT COMPOSITION. Patent Disclaimer filed October 22, 1938, by the assignee, Rumford Chemical l Vorks.

Hereby enters this disclaimer to claim 4.

[Oficial Gazette November 22, 1938.]