US 3001948 A
Description (OCR text may contain errors)
United States Patent l No Drawing. Filed Nov. 26, 1957, 'Ser. No.
4 Claims. (Cl. 252--152) The present invention relates to molded or shaped synthetic detergent compositions of any desired shape or form and to a process for the preparation thereof. More particularly, the invention has to do with the preparation of a detergent bar for toilet and bath use containing as the essential detergent material a special kind of synthetic surfactant, the particles of which can unexpectedly be compacted or pressed into a lastingly sturdy mass or body.
Much effort has been, and is being, expended'in the art of synthetic detergents on the search for a superior detergent bar, and for the improvement of existing nonsoap detergent bars. As is known, synthetic detergents are superior in certain respects to soap; for example, their efliciency is not impaired in hard or salt water. Formulations of soap and certain synthetic detergents have been proposed but without the hoped-for superiority, and indeed suffer from certain disadvantages, .such as poor lather, and poor solubility characteristics. On the other hand, it is desirable that non-soap detergent bars be likesoap in other respects. It is thus desirable that synthetic non-soap detergent bars have low hygroscopicity, proper rate of solution, good lathering characteristics, a
pleasant feeling on contact with the skin, freedom fromstickiness, harmlessness to the human body, and 'ability---- to be produced in conventionalsoap-making equipment. .An essential feature in the preparation of a synthetic detergent bar is that the surfactant employedin its" preparation be capable of being formed, i .e.,' milled,
shaped or molded, into a stable, lastingly sturdy, nonbrittle bar. Accordingly, in order to prepare a bar-with the desired characteristics, it has heretofore been' found necessary to incorporate with the surfactant various organic binders or plasticizers capable of modifying the physical characteristics of the detergent mass and of binding together the detergent particles into a compact cohesive bar or cake. As examples of binding agents there can be-mentioned starches, polyhydric alcohols partially esterified with saturated fatty acids, and other oleaginous materials, such as the higher alcohols, waxes andpetroleum jellyo it a a -A- principal object of the present invention, therefore, istoprepare a novel detergent bar or cake without the requirement of an organic" binder, the bar, moreover,
having satisfactory detersive and sudsing characteristics, a proper rate of solution, good lathering characteristics, ,a low hygroscopicity, whereby mushing and sliming in the presence of water is at a minimum, and one which gives a pleasant feeling to the user during and after use. In accordance-with the invention there are contemplated detergent bar compositions based on normally plastic synthetic detergent material of ammonium detergent .salts of alkylsulfonic acids, and, in association therewith, a second metal detergent salt of alkylsulfonic' acids,- the valkyl groups in both instances being primary'straightchainradicals of about 8, preferably 10, to 20 carbon atoms, the detergent material having an average carbon content of 12 to 16 carbon atoms. Ordinarily, the com- .position contains water in an amount bya weight, based on the detergent material, of about 1 to 10%, usually around 5 to 8%.
In my copending application Serial No. 698,915, filed I 3,001,948 Patented Sept. 26, 1961 sulfonates. However, in order to prepare a cak'e or bat possessing satisfactory characteristics'in accordance'with the aforesaid application, the sulfonates are required to be derived from a rather narrow class of olefins. It has now unexpectedly been found that ammonium n-alkylsulfonates of a broader class can satisfactorily'be solidified, milled and molded into an effective detergent bar by the incorporation with the ammonium n-alkylsulfonate mixture of a second metal n-alkylsulfonate detergent salt material, the alkyl groups again being primary straightchain radicals of 8 to 20 carbon atoms averaging'1'2 to 16 carbon atoms in the molecule. Inasmuch as the results achieved are due to the combination of salts of different cations, the metal salt sulfonatescan be 'derived from a number of metals, including the alkali metals, for example, sodium and potassium; the alkaline earth metals, e.g., barium, calcium and magnesium;.an other metal material, e.g., aluminum.
In general, an amount of second metal n-alkylsulfonate detergent salt is selected within about the range of 10 to 15 mol percent'to mol percent and higher based on total sulfonate content. For optimum results, the amount, of course, will depend on the sulfonate selected. Thus, for the alkali metal sulfonates slightly higher amounts near the top limit of the range can be selected, that is, around 75 mol percent, while with the polyvalent metal sulfonates lesser amounts will be satisfactory, that is, below about 50 mol percent. In most cases, a satisfactory mixture will consist of around.50 mol percent of theammonium n alkylsulfonate. andiSO mol percent of the second metal n-alkylsulfonate material. Informing the detergent material for molding, it is important that an intimate admixture of ammonium and "metal 'sulfonate salts of the character described be effected. Accordingly, a convenient method of preparing the alkylsulfonates falling within the purview of the indisplacement of the ammonium radical by the addition of an appropriate base, e.g., sodium hydroxide, to the desired extent. In the sulfitation reaction some inorganic sulfate may be formed as a side-product,but its presence has not been found to be deleterious. Accordingly, it has been found that up to 20% by weight of the inorganic sulfate, e.g., ammonium or sodium sulfate, can be tolerated in the final composition. By the in situ formation of the sulfonates, intimate admixture of the various'salts can be efiected and the optimum compositions obtained.
A convenient source of the olefins for preparing the sulfonates contemplated by the invention are those that can be derived from the cracking of petroleum wax to yield a mixture primarily of l-olefins having from about 8 to 20 carbon atoms in the molecule. It is the sulfonates of these olefins which can be blended, if necessary, to yield the desired alkylsulfonates having an average carbon content of 12 to 16 carbon atoms. I
Moreover, the sulfonates contemplated by the invention are primarily and essentially those derived from 1- olefins of the specified carbon content, and are essentially of normal or straight-chain structure, although, as is known in the art, a small degree of branching may be permitted without substantial impairment of the detersive action of the material. Accordingly, characterization of the anionic portion of the sulfonate as being a primary straight-chain radical means thatthe sulfonate is derived essentially from normal l-olefins in which a scattering of unsaturation in the molecule and a tolerable degree of chain branching may exist in the mixture of compounds 3 bar are subjective or organoleptic in nature and are based largely on experience derived from the properties possessed by the conventional soap bar. Thus, the over-all nature of the bar, such as waxy appearance and color,
4 active detergent material in the conventional amounts. i.e., from about 5 to 65%, by weight.
In the following examples, hardness, wear rate, and water content were determined by the methods hereinodor, impressions on touch, such as stickiness; and feel- 5 before outlined. Ammonium sulfate content was deing by the user during use and after use are not so much termined by solutions of the anhydrous product bar madeterminable by objective standards as they are by terial in isopropyl alcohol. All the sulfonate dissolves averaged personal reactions. while the sulfate salt is insoluble. The insoluble matter Certain other characteristics of a bar however, lend is collected and dried by conventional gravimetric prothemselves readily to objective evaluation. For example, cedures. the hardness of a bar can satisfactorily be determined by As an example of the invention, calcium-ammonium the use of the conventional grease testing procedure as alkylsulfonates are prepared from a mixture of alphadescribed in ASTM method D-217. The hardness of a olefins of about 8 to 20 carbon atoms and obtained by bar can thus be measured by the depth that a standard the cracking of petroleum wax, the average carbon concone penetrates the sample, set at a temperature of 77 tent of the olefins being around 15. In the preparation ;F., expressed in tenths of a millimeter. Any bar falling of the detergent material, the sulfitation reaction above within the hardness range 2 to 20, more narrowly 5 to described is followed, using aqueous calcium hydroxide 15, is deemed satisfactory from the standpoint of hardwith boiling to displace the ammonium ion to the deness. sired extent. After the addition of the calcium hydroxide, Another important property of a detergent bar is the the product is dried as hereinabove described. The bar solution rate of the active detergent component of the analyzes as follows: bar. As mentioned above, non-soap detergent bars are Alkylsulfonate (calcium alkylsulfonate to ammoni superior to soap in the respect that solubllity and rates um alkylsmfonate mol ratio 10.90) 821 of solution are better in both hard and salt water. At Sulfate content 11 O any rate, a convenient way of measuring the solubility oh Water, wt. percent 6.9 aractenstics of detergent bar is by determining its loss Hardness 6.0 in weight in grams per hand-wash employing ordinary Wear rate Awash 12 tap water having a hardness of 50 p.p.m. and at a tem- 7 perature of about 110 F., averaged from a number of Using the same procedure as outlined above, a numhand-washings by different individuals. It has been debe? of bars are P p in which the activfi detergflli termined that the wear rate of a satisfactory bar may material is a mixture of ammonium and sodium a range from about 0.7 to 1.5 g. per hand wash. sulfonates prepared from petroleum wax C -C olefins. The bars employed in the following examples were The data are tabulated below:
Run No 1 2 a 4 5 e a:l53.%?f?i:E Sulfate, Wt. percent 13 12 15 12 11 lli Water, Wt. percent 6. 5 2. 4 4. 6 4 6. 9 3. Alkylsultonate, Wt. percent. 80 85. 6 81. 4 84 82.2 85.
..-.. unset. satis. good excel. excel. not formed.
Bar characteristics obtained by drum-drying the detergent material to the desired water content into a film, after which the film was ground for homogeneity. The detergent material was then formed into a bar by molding in a conventional soapbar mold. The bars weigh 2-3 ounces and have the approximate dimensions in inches of 2% x 2% x In the preparation of the sulfonate detergent material, aqueous ammonium bisulfite is added to the appropriate olefin material in aqueous alcohol solvent. Following the sulfitation reaction a de-oiling step is performed to remove unreacted hydrocarbons. These can be removed by extraction with a light hydrocarbon, e.g., pentane, or by dilution with water to effect phase formation of the oil and sulfonate followed by separation of the phases, as by decantation. An amount of appropriate base calculated to give the desired amount of mixed sulfonate salts is then added. The alcohol is next removed from the sulfonate layer by distillation. Heating is continued to remove more water until the water content of the product is about 20-25 weight percent of the mixture. At this point the product, a thick slurry which at about 100 C. still flows, is dropped upon a chilled roll, whereupon the product solidifies. The material is then chipped .bfl the roll and air-dried in a conventional drier down to about l-8 weight percent water, as determined for example by the Karl Fischer titration method.
The alkylsulfonate salts are now in condition for molding. If desired, at this stage there may be incorporated into the detergent material other ingredients for the purposes of improving the composition in such properties as odor, color and the like. Accordingly, known fillers, perfumes, dyes and the like can be incorporated With the A bar is formed from ammonium and potassium primary n-alkylsulfonates derived from C -C cracked wax olefins. It analyzes as follows:
Alkylsulfonate (ammonium alkylsulfonate to potassium sulfonates, mol ratio 15:85) 78 Sulfate content 15 Water, wt. percent 5.0 Hardness 7.0 Wear rate, g./wash 1.5
A satisfactory bar is prepared from ammonium and magnesium sulfonate, with the following characteristics:
N-alkylsulfonate (ammonium n-alkylsulfonate to magnesium n-alkylsulfonate, mol ratio 2:1) 74 Sulfate content 15 Water, wt percent 8 Wear rate, g./wash 1.1
.ondary sulfonates are unsatisfactory and cannot be formed into a bar. Similarly, other synthetic detergent materials such as those which form the great bulk of .commercialdetergent compositions, namely, the alkylaryl sulfonates and the alkyl sulfates cannot satisfactorily be formed into bars in accordance with the present invenassists 5 tion. Thus, the alkyl sulfates are chemically unstable and hydrolyze readily in the presence of water, while the alkylaryl sulfonates on the other hand are too soluble and give a sticky feeling when employed in the form of a bar.
1. A synthetic detergent bar consisting essentially of (l) ammonium n-alkyl sulfonate; (2) a second metal nalkyl sulfonate to enable milling and molding in an amount of 10 to 75 weight percent based on (1) and (2); and (3) 1% to 10% water, by weight, based on 1) and (2); the alkyl groups in each of (1) and (2) being primary straight-chain radicals of about 8 to 20 carbon atoms and averaging 12 to 16 carbon atoms, the metal of said second metal n-alkyl sulfonate being selected from the group consisting of alkali and alkaline earth metals.
2. The synthetic detergent bar according to claim 1, wherein the second metal n-alkylsulfonate is sodium nalkylsulfonate.
3. The synthetic detergent bar according to claim 1, wherein the second metal n-alkylsulfonate is selected from the group consisting of calcium and magnesium nalkylsulfonates.
4. The synthetic detergent bar according to claim 1 wherein the water content is 5 to 8%.
References Cited in the file of this patent UNITED STATES PATENTS 2,374,187 Flett Apr. 24, 1945 2,504,411 Harman Apr. 18, 1950 2,813,078 Vitalis Nov. 12, 1957 FOREIGN PATENTS 682,207 Great Britain Nov. 5, 1952 OTHER REFERENCES 20 ous Solutions of Magnesium n-Alkane sufonates, Jour.
Amer. Chem. Soc., 73, 5411-14 (1951).
Lingafelter et al.: Extent of Hydration of Some Crystalline Phases of Sodium l-Alkanesulfonates, Jour. of Physical Chemistry, 57, 428-429 (April 1953).