UNITED STATES PATENT OFFICE 2,510,510 GERMICIDAL DETERGENT COMPOSITION Elwyn E

Patented June 6, 1950 2,510,510 UNITED STATES PATENT OFFICE 2,510,510 GERMICIDAL DETERGENT COMPOSITION Elwyn E. Mendenhall, Pittsburgh, Pa., assignor to Economics Laboratory, Inc., St. Paul, Minn., a corporation of Delaware No Drawing. Application October 3, 1945, Serial No. 620,172 9 Claims. (CL 252-107) 2 . This invention relates to improved germicides invention are not noticeably affected by light, and germicidal detergents and water softening and do not stain the skin. They may be used compositions, and more particularly to silver with soaps, in acid, neutral or alkaline Solution, containing glassy systems of value for Such uses. and are resistant to precipitation on contact with The usefulness of silver as a germicide has 5 organic materials found in wash or other Solu long been recognized. Numerous silver-contain tions. For these reasons, and in view of the high ing compounds have been used as antiseptics, activity of the compositions, that is, high germi such as silver acetate, silver bromide, silver chlo cidal effectiveness with low concentration of sil ride, and silver citrate. Silver iodide has been ver, they are of benefit as germicides and of par used in preparing colloidal silver preparations, 10 ticular advantage in germicidal detergentS alad and silver nitrate has also been used for this as germicidal water Softening agents. and numerous other purposes. Various silver The new compositions themselves may be effec vitellin preparations have been used as antiseptics tive water softening agents and may have effec in the treatment of the eyes, nose and throat. tive detergent properties, as when the composi Most such silver compounds are possessed of 15 tions consist of complex glassy phosphates con certain undesirable characteristics which detract taining some silver and substantial proportions of from their usefulness. For the most part, they alkali metal, or the compositions may be essen are sensitive to light and tend to precipitate tially germicidal in nature as in the glassy prod free silver upon exposure to light. This property ucts in which silver is the Sole or predominating is a distinct disadvantage in the use of these 20 metal and in either case they may be associated compounds and compositions as antiseptics. The with appropriate detergent or water softening shelf life of most silver-containing germicides is materials, Such as alkaline salts, Soaps, Synthetic short and somewhat undependable. Further, it detergents Such as Sulfated alcohols, Sulfated has been considered impractical to use silver monoglycerides, Sulfonated alkyl naphthalene preparations in or with natural water Solutions 25 derivatives, meta or polyphosphates and the like. because of incompatibility. So far as I am aware The glassy Silver-containing phosphates exhibit .no satisfactory germicidal detergent or germi high activity over a wide range of pH, and there cidal water softening composition, in which the fore may be used with advantage to impart germicidal properties are due to silver, have been germicidal properties to water softening or de heretofore suggested. 30 tergent compositions which may be acid, neutral The products of the present invention are or alkaline in character, thus embracing Sub glassy systems comprising the phosphates and stantially the entire range of the recognized water polyphosphates of silver, the complex phosphates Softening and detergent materials. Y and polyphosphates of silver and another metal The germicidal compositions of the invention or metals, advantageously an alkali metal or 35 include the glassy silver phosphates, ranging alkaline earth metal, or both, and composi from fused silver metaphosphate tions which contain one or more Such glassy na terials along with other materials which are use (Agao:P2O5=1:1) ful from the standpoint of imparting detergent up to the fused silver pyrophosphate or water softening properties to the compositions, 40 or enhancing the germicidal properties of the (Ag2O:E2O5=2:1) silver. and complex fused glassy products, having in The glassy products of the invention are es addition to a silver content a content of other sentially fusion products which may be regarded metal or metals, advantageously alkali metal or as formed of one or more metal oxides and phoS- 45 alkaline earth metal, although products contain phorous pentoxide, although not necessarily or ing other metals than these are included. The even desirably produced from metal oxide and exact composition or structure of these fused or phosphorous pentoxide, and in which the atomic glassy products is not known, but it is common or molecular arrangement is that typical of glassy practice to designate products of this type (i. e. systems as distinguished from crystalline Systems. 50 'glasses') in terms of their content of metal The invention includes products which are pre oxide and phosphorous pentoxide, as, for example dominantly or primarily glassy in nature but in the case of glassy silver tetrapolyphosphate, which may include a considerable proportion of which may be designated as 3Ag2O:2P2O5, and crystalline material imbedded in the glassy, in general this system of nomenclature will be matrix. The products may be in the -form of 55 followed in this specification. powder, granules, globules or beads, flakes or the The invention includes, as new products, the like, and the term "glassy' is not intended to de fused silver phosphates in which the Ag2O:POs note the gross physical form of the products, but ratio is between about 1.1:1 and about 1.9:1, rather their atomic or molecular arrangement. which - products are advantageous for use as The glassy silver-containing phosphates of the 60 germicides, or as ingredients of germicidal deter 2,510,510 3 4. gents or water softeners, and the complex fused compositions, consisting essentially of silver oxide products which contain, considered analytically, and phosphorous pentoxide (fused as a glass) in addition to silver oxide and phosphorous may also be used in germicidal detergent com pentoxide, the oxide of another metal or metals, positions and germicidal water softening com particularly of an alkali metal or metals or com positions by admixture with appropriate deter binations of the alkali metals and the alkaline gent or water softening ingredients such as soaps, earth metals, although glassy products contain synthetic detergents, sodium phosphates, par ing other metals, such as the heavy metals, are ticularly metaphosphates and polyphosphates, included. alkaline salts such as sodium metasilicate and While the glassy silver phosphates themselves 10 the like, but in general for these latter purposes, exhibit remarkably high germicidal activities, the the complex products containing an alkali metal, products in which the Silver is associated with or an alkali metal and an alkaline earth metal, another metal or metals, particularly one or in addition to the silver, are advantageous. Ex more of the alkali metals, because they show even tensive tests have shown that on the basis of more pronounced germicidal activity, calculated 5 silver content of the solution tested, the complex on the basis of silver content required for effective phosphates containing silver oxide, sodium oxide killing action against typical microorganisms, or the like and phosphorous pentoxide, as by and because the inclusion of a proportion of fusing together a mixture of materials which alkali metal in the glassy product has the effect gives a glassy phosphate containing a relatively of substantially increasing solubility or rate of 20 small percentage of silver, such as about 2%, are solubility, are of particular advantage for use in more effective germicidally than are the composi or as germicidal detergents and water Softening . tions consisting essentially of silver oxide and agents, where the expense of the silver is an item phosphorous pentoxide. This we attribute to the of consequence. Thus, complex glassy phosphate fact that the phosphate radical exerts an en systems containing both silver and sodium which 25 hancing action in compositions containing silver show highly effective germicidal activity, as as the effective germicidal material and Substan exhibited by the killing of 99.5% of E. coli by tially promotes the activity of the silver, such as standardized tests with silver concentrations as to make it more effective, or effective in a lower low as 1 or 2 parts per million, are readily pre concentration, or more resistant to inactivating pared in accordance with the invention and are 30 influences of other materials, such as the con of great value for use in germicidal detergents stituents of natural water, organic matter, and or water softening materials. the like. Furthermore, in these complex products con For industrial germicidal detergent purposes, taining an alkali metal in addition to the silver, as for materials intended for use in washing and which contain but a Small proportion of 35 dishes or other utensils, for disinfecting purposes, silver such as is economically feasible in a germi and the like, the final detergent compositions will cidal detergent or water softener, the silver seems ordinarily not contain more than about 2% of to reduce the hygroscopicity of the product well silver, and effective compositions containing-sub below that of the alkali metal metaphosphates stantially less silver than this may be readily and polyphosphates more or less commonly used 40 prepared in accordance with the invention. In today in detergents and water softening agents, general,

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