US 3223643 A
Description (OCR text may contain errors)
United States Patent O 3,223,643 LIQUID ACID-DETERGENT-SANITIZER COMPOSITION Andrew B. Law, Levittown, Pa., assignor to Rohm & Haas Company, Philadelphia, Pa., a corporation of Delaware No Drawing. Filed Nov. 12, 1964, Ser. No. 410,705 5 Claims. (Cl. 252-106) This application is a continuation-impart of my application Serial No. 146,014 which was filed on October 18, 1961, and which has since been abandoned.
This invention relates to a liquid acid-detergent-sanitizer of high hard water tolerance. It has particular reference to a formulation containing a quaternary ammonium composition as the sanitizer and a nonionic as the detergent.
One of the principal components of the present invention is an outstanding commercially available sanitizer which consists of an aqueous solution of a mixture of alkyl dimethyl benzyl ammonium chlorides. The mixture consists of alkyl dimethyl benzyl ammonium chlorides whose alkyl groups can range from C to C although its most effective germicidal components are those whose alkyl groups are C (lauryl or dodecyl), C (myristyl or tetradecyl) and C (cetyl or hexadecyl). The proportions of the C -C components can vary, depending upon the manufacturer and the particular batch of the product. However, for the purposes of the present invention the proportions are not critical, the sanitizer being effective in the various proportions, some to a greater and others to a lesser degree, in the invention as described hereinbelow.
One of the most outstanding features of this conventional quaternary sanitizing composition is its exceptional effectiveness in hard water. The sanitizing dilution for quaternaries is considered standard in the United States and in most foreign countries is 200 p.p.m., and in many states and local governments this requirement is specified by law. At this dilution the hard water ceiling for the quaternary described above is 550 p.p.m. hard water. This means that the quaternary is capable of killing 99.999 percent of specified test organisms (generally Escherichia coli), in 30 seconds, in water containing up to 550 p.p.m. (32 grains per gallon) hardness calculated as CaCO The test method used is the Chambers modification of the Weber-Black technique as described in Methods of Analysis of the Association of Official Agricultural Chemists (AOAC), 9th Edition, 1960 (as originally described in the Journal of that association, vol. 41, No. 1, 1958). In accordance with this procedure an inoculum containing a known number of bacteria is added to hard water solutions of the acid-detergent-sanitizer formulations. Aliquots of the solutions are then removed at timed intervals and the quaternary inactivated by diluting 1:10 with a lecithin-Tween 80 solution known commercially as Letheen. Tween, a product of the Atlas Powder Company, Wilmington, Delaware, is a fatty acid ester of anhydrosorbitols which have been solubilized by etherifying the free hydroxyl groups with ethylene oxide. Agar pour plates are prepared from the Letheen solutions, incubated at 37 C. for 48 hours and counted for surviving bacteria.
In copending application Serial No. 146,016, filed by me on October 18, 1961, and now abandoned, it was disclosed that some detergents employed with the sanitizer described above greatly reduced the high hard water tolernace of the quaternary. In fact, the invention in that case was the discovery that certain ethoxylated t-carbinamines were the only surfactants that did not so lower the high hard water tolerance. It was also disclosed therein that the described combination of detergent-sanitizer was quite compatible with alkali.
There are many applications in which it is desired to employ a detergent-sanitizer under conditions where acid, such as phosphoric acid, was present and the composition had a pH of about 2.53.0. However, it has been observed that the presence of phosphoric acid reduces the rate of kill of the alkyl dimethyl benzyl ammonium chloride sanitizers at certain low water hardness levels, and this fact has made the provision of a satisfactory acid-detergent-sanitizer using this combination of acid and quaternary most improbable. It is, therefore, a surprising discovery to have found that a highly compatible acid-detrergent-sanitizer incorporating phosphoric acid and the described sanitizer can be made without adversely affecting either the high hard water ceiling of the quaternary or reducing its rate of kill in water of low hardness, by employing as the detergent a certain class of alkylaryl polyether alcohol-s. This class includes octyl and nonyl phenoxypolyethoxyethanols having from about 5 to 7.5 ethylene oxide units, and polypropyleneoxypropyl, octyl or nonyl phenoxypolyethoxyethyl ethers having the structural configuration in which R equals a C -C alkyl group, 20:5 to 7.5, and 3 :10 to 15. The class of detergents used is critical to the successful operation of the acid-detergent-sanitizer. This is well illustrated below where evidence is given of a large number of otherwise excellent detergents which were tried in combination with the same acid and sanitizer, but were unacceptable because of the adverse effect they had on the hard water ceilings or floors, as the case may be.
Keeping in mind the requirement that to be satisfactory an acid-detergent-sanitizer must not only have an adequate hard water ceiling, but the detergent in the composition also must not reduce the rate of kill of the germicide in the composition when the composition is employed in water of low hardness. In other words, the composition must not produce a hard water floor. This floor may be described as that hardness, in numbcr of p.p.m. of a synthetic hard water, below which the 200 p.p.m. of active quaternary formulation does not kill 99.999 percent of the inoculum in 30 seconds, but above which the required kill of inoculum is obtained. Put another way, the formulation could pass the Chambers test above 300 p.p.m. Water hardness but not below this level of hardness.
In Table I, which follows, there are listed a number of detergents, almost all of them commercially wellknown, which were tested for compatibility with the hard water tolerance of the sanitizer described above (C C alkyl dimethyl benzyl ammonium chloride composition) in a phosphoric acid environment. The use ratios were the preferred minimal amounts, namely 200 p.p.m. of the sanitizer and 200 ppm. of the detergent, plus sufficient phosphoric acid to bring the pH of the solution to between 2.5 and 3.5. Generally, the amount of phosphoric acid needed to attain a pH within this range is between 200 and 900 p.p.m. Of course, if more sanitizer and detergent are employed more acid will be required. Keeping within the indicated pH range is critical to the successful operation of the invention when it is desired to produce compositions which will have both satisfactory ceilings and satisfactory floors. In preparing the compositions, incidentally, the desired amounts of the acid, detergent and sanitizer were mixed together, and the balance made up to mark by addition of distilled water.
Cetyl stearyl polyethoxyethanol Polyethylene glycol monoether of octyl phenol formaldehyde condensation product (25% I1 0 solution). Octyl phenoxy polyethoxyethanol Sodium salt of sulfated t-C1r-14H23-29NH(CH2CH2O)n Suliated tC1l l4HZ3 WNH(CHQGHQO)uI'I n-D odecyl amine Nonylphenoxypolyethoxyethanol Methylene bis-diamylphenoxy polyethoxyethanol- Octylphenoxy polyethoxyethanol Dinonyl phenoxy polyethoxyethanol Poltipropyleneoxypropyl octylphenoxypolyethoxyethyl e er.
E 21. E0 7.5; P0 13.
In Table II, which follows, there are shown a number of detergents identified in Table I and their efiect upon a solution containing 200 p.p.m. of the C -C alkyl dimethyl benzyl ammonium chloride sanitizer described 35 p.p.m. of each of two detergents.
above, and 400 p.p.rn. of phosphoric acid. In all cases the concentration of the detergent was 200 p.p.m. In one instance this concentration was arrived at by using 100 TABLE 11 Water Hardness in p.p.m. Detergent N0. (From Table I) 1 TS/ml TNC 464, 000 78,000 11,000 13, 600 188,500 Percent Kill. 99 99. 4957 99. 9152 99. 9880 99. 9852 99. 7951 2--...- 'IS/ml TNG 877, 500 181, 100 6,800 4, 100 81,500 Percent Kill... 99 99. 0462 99.8032 99. 9709 99. 9955 99. 9114 3+ T /m1 994,500 497,200 1, 50 19 4+- Percent Kill 98. 9190 99. 4596 5 /ml TNO TNC Percent Kill.-. 99 99 6 [m1 t TNC 'INC Percent Kil1 99 99 7 m1 TNC TNC Percent Kill 99 99 'IS/ml 0 Percent Kill 100 100 No'rEs:
*Elapsed time in all of the above experiments was 30 secs.
TS=Total survival, number of bacteria/ml.
It will be seen from the data in Table II that only detergents Nos. 8, 17 and 19 met the hard water ceiling specification of the Chambers (Weber-Black) test described above at all hardnesses examined, when in combination, as shown, with the acid and sanitizer. The same three detergents also showed no appreciable hard water floor in waters of 250 p.p.m. of lower hardness levels, as shown in Table III below.
NorE.*Efieet of a solution containing 200 ppm. of the Cs-Crs alkyl dimethyl benzyl ammonium chloride sanitizer described above, and 400 p.p.m. of phosphoric acid. In all cases the concentration of the detergent was 200 p.p.m., and the elapsed time of each experiment was 30 seconds.
For the sake of comparison, the data in Table IV show the eifect which occurs when the same quantity of phosphoric acid (400 p.p.m.) is mixed with the same quantity (200 p.p.m.) of the same sanitizer as in the previous tables. For a further comparison, the data in Table V show the effect which occurs when the same quantity of the acid and the same quantity of the santizer are mixed with one of the best known and most eflicient prior art detergents, namely No. 3 in Table I.
TABLE IV Water Hardness in p.p.m. Detergent None TS/ml 49, 400 750 57, 200 Percent Kill 99. 9547 99. 9993 99. 9475 N o'rE.-+=E1apsed time 30 seconds.
*TNO =To0 numerous to count. +=E1apsed time 30 seconds.
As Table IV shows, the combination of the acid and the sanitizer produces a floor at each of the three levels of water hardness tested. Table V shows that merely the addition of a detergent, even one of the best prior art detergents, will not eliminate the floor (or raise the celling). It takes the right combination of acid-detergentsanitizer, as discussed just before Table I and as shown in Tables II and II, to provide a fully compatible system, one which is suitable with regard to both the ceiling and the floor of the formulation. This combination is critical to the successful operation of the invention, and is, therefore, precisely what I have defined in the claims set forth below.
1. A liquid acid-detergent-sanitizer composition consisting of phosphoric acid, a C C alkyl dimethyl benzyl ammonium chloride sanitizer, and an alkylaryl polyether alcohol detergent from the class consisting of octyl and nonyl phenoxyethanols having an average of from about 5 to about 7.5 ethylene oxide units, and polypropyleneoxypropyl octyl and nonyl phenoxypolyethoxyethyl ethers having the structural configuration in which R: a C -C alkyl group, x: 5 to 7.5 and y:10 to 15, the amounts of said sanitizer and detergent being in substantially a 1:1 ratio, and the amount of phosphoric acid being in suificient quantity to give a pH of between about 2.5 and 3.5, said ratio and pH being in effect when the composition is diluted with Water so as to contain between 200O parts per million of the acid and at least about 200 parts per million each of the sanitizer and of the detergent.
2. The composition of claim 1 in which the sanitizer is a mixture principally consisting of C C and C dimethyl benzyl ammonium chlorides.
3. The composition of claim 1 in which the alkylaryl polyether alcohol is octylphenoxypolyethoxyethanol in which the ethylene oxide content averages about 7.5 moles.
4. The composition of claim 1 in which the alkylaryl polyether alcohol is octylphenoxypolyethoxyethanol in which the ethylene oxide content averages five moles.
5. The composition of claim 1 in which the alkylaryl polyether alcohol has the structural configuration CBHHQO mcmoim intomn References Cited by the Examiner UNITED STATES PATENTS 2,860,106 11/1958 Little et al 252-436 2,903,486 9/1959 Brown et a1 260-613 2,950,253 8/ 1960 Kling et al 252152 2,950,255 8/1960 Golf 252152 3,021,372 2/1962 Dupre et al 260-613 JULIUS GREENWALD, Primary Examiner.