US 2510510 A
Description (OCR text may contain errors)
Patented June 6, 1950 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 This invention relates to improved germicides and germicidal detergents and water softening compositions, and more particularly to silvercontaining glassy systems of value for such uses.
The usefulness of silver as a germicide has long been recognized. Numerous silver-containing compounds have been used as antiseptlcs, such as silver acetate, silver bromide, silver chloride, and silver citrate. Silver iodide has been used in preparing colloidal sllverpreparations, and silver nitrate has also been used for this and numerous other purposes. Various silver vitellin preparations have been used as antiseptics in the treatment of the eyes, nose and throat.
Most such silver compounds are possessed of certain undesirable characteristics which detract from their usefulness. For the most part, they are sensitive to light and tend 'to precipitate free silver upon exposure to light. This property is a distinct disadvantage in the use of these compounds and compositions as antiseptics. The shelf life of most silver-containing germicides is short and somewhat undependable. Further, it
has heen considered impractical to use silver preparations in or with natural water solutions because of incompatibility. So far as I am aware .no satisfactory germicidal detergent or germicidal water softening composition, in which the germicidal properties are due to silver, have been heretofore suggested.
The products of the present invention are glassy systems comprising the phosphates and polyphosphates of silver, the complex phosphates and polyphosphates of silver and another metal or metals, advantageously an alkali metal or alkaline earth metal, or both, and compositions which contain one or more such glassy materials along with other materials which are useful from the standpoint of imparting detergent or water softening properties to the compositions, or enhancing the'germicidal properties of the silver. I
The glassy products of the invention'are essentially fusion products which may be regarded as formed of one or more metal oxides and phosphorous pentoxide, although not necessarily or even desirably produced from metal oxide and phosphorous pentoxide, and in which the atomic or molecular arrangement is that typical of glassy systems as distinguished from crystalline systems.
The invention includes products which are predominantly or primarily glassy in nature but which may include a considerable proportion of crystalline material imbedded in the glassy,
matrix. The products may be in the-form of powder, granules, globules or beads, flakes or the like, and the term glassy is not intended to denote the gross physical form of the products, but
- rather their atomic or molecular arrangement.
The glassy silver-containing phosphates of the and do not stain the skin. They may be used with soaps, in acid, neutral or alkalinesolution, and are resistant to precipitation on contact with organic materials found in wash or other solutions. For these reasons, and in view of the high activity of the compositions, that is, high germicidal efiectiveness with low concentration of silver, they are of benefit as germicides and of particular advantage in germicidal detergents and as germicidal water softening agents.
The new compositions themselves may be effective water softening agents and may have efiective detergent properties, as when the compositions consist of complex glassy phosphates containing some silver and substantial proportions of alkali metal, or the compositions may be essentially germicidal in nature as in the glassy products in which silver is the sole or predominating metal and in either case they may be associated with appropriate detergent or water softening materials, such as alkaline salts, soaps, synthetic detergents such as sulfated alcohols, sulfated monoglycerides, sulfonated alkyl naphthalene derivatives, meta or polyphosphates and the like. The glassy silver-containing phosphates exhibit high activity over a wide range of pH, and therefore may be used with advantage to impart germicidal properties to water softening or detergent compositions which may be acid, neutral or alkaline in character, thus embracing substantially theentire range of the recognized water softening and detergent materials.
The germicidal compositions of the invention include the glassy silver phosphates, ranging from fused silver metaphosphate (Ag20:P2O5=1:l)
up to the fused silver pyrophosphate (Ag202P205=221) and complex fused glassy products, having in addition to a silver content a content of other metal or metals, advantageously alkali metal or alkaline earth metal, although products containing other metals than these are included. The exact composition or structure of these fused or glassy products is not known, but it is common practice to designate products of this type (i. e. glasses) in terms of their content of metal oxide and phosphorous pentoxide, as, for example in the case of glassy silver tetrapolyphosphate, which may be designated as 3Ag2OZ2P2O5, and in general this system of nomenclature will be followed in this specification.
The inventionincludes, as new products, the
' fused silver phosphates in which the AgzozPzOs ratio is between about 1.1:1 and about 1.9:1,
gents or water softeners, and the complex fused products which contain, considered analytically, in addition to silver oxide and phosphorous pentoxide, the oxide of another metal or metals, particularly of an alkali metal or metals or combinations of the alkali metals and the alkaline earth metals, although glassy products containing other metals, such as the heavy metals. are included.
While the glassy silver phosphates themselves exhibit remarkably high germicidal activities, the products in which the silver is associated with another metal or metals, particularly one or more of the alkali metals, because they show even more pronounced germicidal activity, calculated on the basis of silver content required for effective killing action against typical microorganisms, and because the inclusion of a proportion of alkali metal in the glassy product has the effect of substantially increasing solubility or rate of solubility, are of particular advantage for use in 4 com ositions, consisting essentially of silver oxide and phosphorous pentoxide (fused as a glass) may also be used in germicidal detergent compositions and germicidal water softening comor as germicidal detergents and water softening agents, where the expense of the silver is an item of consequence. Thus, complex glassy phosphate systems containing both silver and sodium which show highly effective germicidal activity, as exhibited by the killing of 99.5% of E. coli by standardized tests with silver concentrations as low as l or 2 parts per million, are readily prepared in accordance with the invention and are of great value for use in germicidal detergents or water softening materials.
Furthermore, in these complex products containing an alkali metal in addition to the silver, and which contain but a small proportion of silver such as is economically feasible in a germicidal detergent or water softener, the silver seems to reduce the hygroscopicity of the product well below that of the alkali metal metaphosphates and polyphosphates more or less commonly used today in detergents and water softening agents, and the glassy compositions of this invention are less susceptible to caking than are these present day commercial products, in addition to the fact that they are remarkably efiective gerniicidally.
In contrast with the previously known silver germicides the products of the present invention are quite reliable, and their germicidal action is quite reproducible. They do not exhibit the erratic action frequently observed with silver nitrate, for example. They are also quite lacking in caustic properties, and are not irritating 0r caustic as are many of the known silver germicides, such as silver nitrate. They may therefore be used even in solutions to which the skin is subjected for prolonged periods, such as in compositions for hand dish-washing, 'without producing undue irritation or caustic effects.
The new compositions are effective against both gram positive and gram negative organisms, in contrast with many germicidal materials, which are effective against one or the other but not both types. The new compositions may be used in water of relatively high temperature, as their germicidal activity is not destroyed at temperatures normally experienced with detergents, water softeners or the like.
In general, for simple germicidal compositions, consisting essentially of silver oxide and phosphorous pentoxide, to be used as germicides or disinfectants, the silver concentration in the products may be quite high, ranging as high as about 71%, compositions which correspond to a silver oxide, phosphorous pentoxide ratio of 1.1:1 to 1.9:1 being particularly valuable. Such glassy positions by admixture with appropriate detergent or water softening ingredients such as soaps, synthetic detergents. sodium phosphates, particularly metaphosphates and polyphosphates, alkaline salts such as sodium metasilicate and the like, but in general for these latter purposes, the complex products containing an alkali metal. or an alkali metal and an alkaline earth metal, in addition to the silver, are advantageous. Extensive tests have shown that on the basis of silver content of the solution tested, the complex phosphates containing silver oxide, sodium oxide or the like and phosphorous pentoxide. as by fusing together a mixture of materials which gives a glassy phosphate containing a relatively small percentage of silver, such as about 2%, are I more eflective germicidally than are the compositions consisting essentially of silver oxide and phosphorous pentoxide. This we attribute to the fact that the phosphate radical exerts an enhancing action in compositions containing silver as the effective germicidal material and substantially promotes the activity of the silver, such as to make it more eifective, or efl'ective in a lower concentration, or more resistant to inactivating influences of other materials, such as the constituents of natural water, organic matter, and the like.
For-industrial germicidal detergent purposes, as for materials intended for use in washing dishes or other utensils, for disinfecting purposes, and the like, the final detergent compositions will ordinarily not contain. more than about 2% of silver, and effective compositions-ecntainmg-sub-- stantially less silver than this may be readily prepared in accordance with the invention. In general, it is advantageous to have the silver present, not as a simple glassy silver phosphate, but as a glassy complex phosphate containing silver and alkali metal or alkali metal and alkaline earth metal, and to include along with this complex glassy phosphate, which itself may have, and usually will have, effective water softenin properties, one or more of the commonly used detergents such as sodium metasilicate, trisodium phosphate, a synthetic wetting agent, such as one of the Nacconols, or the like. Eil'e'ctive detergents with a soap base may be produced by mixing one of these complex phosphates with a soap, such as a white soap flake, white floating soap, or a laundry soap, consisting oi soap plus alkaline salts, usually silicate. For special germicidal detergent purposes, as for a product adapted for surgical and hospital use, as in the washing of hands of surgeons, cleaning of surgical instru-- ments, operating rooms, etc., products containing considerably more silver, for example up to 5% of silver, are practical from a cost standpoint and may be regarded as effective germicidal detergents within the scope of this invention. Again it is advantageous to use the complex silver-alkali metal or alkali metal-alkaline earth metal phosphates rather than the simple silver phosphates, in all cases the phosphate being in the form of the glassy systems previously described.
For germicidal detergent and water softening compositions, the solubility of the product is a factor of some importance. The alkali metal silver phosphates of the invention, probably because of the influence of the alkali metal and the lower content of silver, are, particularly where the alkali metal content is relatively high, relatively soluble and advantageous for that reason. In some cases, a product which dissolves slowly is of advantage and for such purposes, products which contain but a small amount of alkali metal and have correspondingly increased content of silver or of alkaline earth metal or both are advantageous. The products used in accordance with the invention may be prepared by mixing. together appropriate metalphosphates for any desired composition and then fusing them and quenching the melt to obtain a glassy produc't. Compounds other than phosphates may be included in the mixture which is fused providing harmful elements are not used or such undesired element or elements arevolatile under the conditions of fusion. Thus the silver polyphosphates may be prepared by fusing together in appropriate proportions such materials as silver orthophosphate, silver pyrophosphate, silver metaphosphate, phosphoric acid or phosphorous entoxide, silver oxide, silver compounds in which the undesired element or elements are volatile under the conditions of fusion, or selected groups of such materials.
The silver phosphate to be obtained may be considered as consisting of the oxides AgzO and P205 in the desired ratio and by appropriate selection of the mixture to be fused the desired glassy phosphate may be obtained. Thus it will be noted that the compound silver metaphosphate may be considered as consisting of the oxides AgzO and P205 in a one to one ratio (1:1) and that the compound silver pyrophosphate may be considered as consisting of the oxides AgaO and P205 in the ratio of two to one (2:1) Thus, by using appropriate quantities of silver metaphosphate and silver pyrophosphate, compositions consisting of any ratio of the oxides between one to one and-twotrone (1:1 and 2:1) may be obtained.
Likewise it will be seen that by using silver orthophosphate, which has a. metal oxide to P205 ratio of three to one (3:1) and another silver phosphate or phosphorous pentoxide in appropriate proportions, it will be possible to prepare a' silver phosphate of any desired metal oxide to P205 ratio.
It has long been known that the alkali-metal polyphosphates, and in particular sodium polyphosphates, may be prepared by fusing together appropriate quantities of NaOH and HaPO4 (or certain sodium phosphates), and then quickly chilling the melt. Glassy polyphosphates of various compositions are obtained. By inclusion of an appropriate amount of silver oxide, a silver phosphate or other suitable silver-containing compound in a mixture so fused, complex phosphates containing silver and alkali metal are readily prepared, while by the addition of calcium oxide or phosphate or magnesium oxide or phosphate or the like, the corresponding complex phosphates of silver, alkali metal and alkaline earth metal may be prepared. Manifestly, such materials as sodium carbonate may be used as constituents in preparing the materials in accordance with well known practice, as may other metal oxides or metal compounds as those of the heavy metals.
The invention will be illustrated by the following examples, but it is not limited thereto:
EXAMPLE 1 A mixture consisting of 74.752 parts by weight of silver metaphosphate, and 60.552 parts of silver pyrophosphate was intimately mixed and fused. The melt was quickly chilled by pouring it upon a cooled stainless steel slab in small beads. The composition of the above fusion may be considered as AgzO and P205 in the ratio 4:3, and corresponds to the hypothetical compound AgaPsOw, having a silver content of EXAMPLE 2 EXAMPLE 3 A mixture of 18.688 parts of silver metaphosphate and 60.552 parts of silver pyrophosphate was treated as in Example 1, by mixing, fusing and chilling. The resulting product contains AgzO and P205 in the ratio of 5:3 and corresponds to the formula AgsPaOro having a silver content of 68%.
EXAMPLE 4 27.73 grams of silver metaphosphate was treated with 10 ml. of 85% orthophosphoric 30 acid (having a. specific gravity of 1.689, and being equivalent to 10.39 grams 'of P205) Upon strong heating a. clear fusion was obtained. The product was quenched by pouring onto a cold steel slab. It has a composition corresponding to the formula AGzO.2P2O5 and contains 40.5% silver.
EXAMPLE 4A A glassy sodium silver polyphosphate with a MO:PzO5 .ratio of 1.111 and a silver content of 0.5% was made as follows. 24.75 grams of silver nitrate was dissolved in a small amount of water and added to 2484 milliliters of 75% phosphoric acid. This solution was then poured slowly over, and thoroughly mixed with, 1750 grams of 'sodium carbonate i a steel pan. This mixture was then dehydrated and the dry material transferred to a crucible, placed in a furnace and melted and held at above the melting temperature fora short time. The m'elt was then quenched by pouring onto a cooled stainless steel slab. 7
EXAMPLE 5 EXAMPLE 6 A mixture of 9.415 parts by weight of a sodium polyphosphate (4NaaO:3PzO.-i) together with 4.16 parts of AG4P2O1 and 5.0 parts AgPOa, after being intimately ground together, was fused.
The mass was then quickly chilled by pouring in a. thin layer or in small beads upon a stainless steel slab. The resulting glassy product contains 31.3% silver.
EXAIVIPLE' 7 A mixture of 5 parts by weight of KH2PO4, 7.5 parts by weight of K2HPO4 and 0.573 part by weight of A8903. after being intimately ground together was fused. The mass was then quickly chilled by pouring in a thin layer or in small beads upon a cold stainless steel slab. The resulting product is a. glassy material approximating the composition .of potassium-silver tetra. phosphate in which the metal oxide to P205 ratio is 3:2, and the silver content equal to 2.75%.
The alkaline earth metal silver polyphosphates are for the most part difliculty soluble, which is advantageous for some uses as where it is desired to employ a. germicide which goes into solution slowly and over a rather long period of time, or where it is to be used in a filtering operation, for example, where a germicide is desired and where the product must dissolve slowly. These materials are not well fitted for use as simple germicides, or as ingredients of germicidal detergents or water softening compositions, but are useful for such purposes as those just referred to. Such materials are illustrated by the following two examples.
EXAMPLE 8 EXAMPLE 9 A mixture of 10.9,grams of MgCHaPOOz and 0.268 gram of AgPm was fused and quenched. The product is a magnesium silver meta phosphate containing 13.36% magnesium and 1.66% silver.
The alkali-metal alkaline earth-metal silver polyphosphates in general possess solubilities somewhat intermediate to the solubilities of the alkali-metal silver polyphosphates and the alkaline earth silver polyphosphates. The greater the proportion of alkali-metal, the greater is the solubility. Thus by varying the proportions of the metals used, the solubility of the product may be varied. This fact enables the manufacturer to tailor the product to fit the desired situation.
In general these substances are prepared in a manner similar to that previously described for the alkali-metal silver polyphosphates. The appropriate alkali-metal phosphate, alkaline earth-metal phosphate, and silver phosphate in proper amounts are intimately mixed together, fused, and quenched. As examples of alkalimetal alkaline earth-metal silver polyphosphates, we may cite the following:
EXAMPLE 10 18 parts by weight of Mg(H2PO4)2, magnesium monobasic (primary) phosphate, was intimately mixed with 3.24 parts of Ag3PO4 and 95.5 parts of a. sodium polyphosphate (4Na2O:3P2Os) and the mixture fused and quenched. The resulting glassy product contains metal oxides and P205 in a molecular ratio of approximately 4:3, a silver content equal to 2.21%, and 9. Mg content of EXAMPLEH 10 parts by weight of Ca(H:PO4)2.H2O, calcium monobasic phosphate was first dehydrated, then mixed with 5.89 parts of sodium polyphosphate (having a NaaOtPaOs ratio of 4:3) and 0.483 part of silver orthophosphate. The mixture was then fused and quenched. The product is a glassy composition containing 1.12% calcium and 2.36% silver.
Another convenient method for the preparation of certain of these silver products is by electrolysis of the appropriate phosphate in the fused condition, using a silver anode and an inert metal or carbon as cathode. In this manner the silver is introduced into the fusion in a highly active germicidal condition. When the desired concentration of silver in the product is attained the electrolysis is discontinued and the fused material is chilled in the usual manner. Thus, sodium silver polyphosphates, potassium silver polyphosphates, sodium magnesium silver polyphosphates, and other alkali and/or alkaline earth silver polyphosphates have been prepared and have been found to possess strong germicidal activity.
The extreme effectiveness of the glassy silver phosphates, and particularly those having a silver oxide: phosphorous pentoxide ratio in the range of 1.1:1 to 1.9:1, and of the complex silvercontaining glassy phosphates has been demonstrated by appropriate tests against a number of bacteria, and in general, as measured by the concentration of silver in the test solution required to kill the bacteria by standardized test, is substantially higher than that observed with other silver-containing materials.
The germicidal activity of the various preparations under consideration was tested by a modified F. D. A. procedure quite simiiar tirthemethod of testing germicidal detergents which is described by Cade and Halvorson on page 17 of vol. 10, No. 8, 1934, issue of Soap. The exact procedure used is as follows:
A 10 ml. sample of the solution to be tested is placed in a 1" x 6" test tube. A series of these tubes of solutions to be tested is placed in a rack in a water bath maintained at a temperature of 40:0.2 C. When these medication tubes have attained the temperature of the water bath a 0.3 ml. portion of a 24 hour broth culture is added to each at a known time and the contents of each tube mixed thoroughly immediately after addition of the culture. course, that proper bacteriological technique is to be followed in all of the operations involved in this method of testing.) At the end of the desired time-of-medication interval a 4 mm. loopful of medicated solution is introduced into a tube of molten (43-45 C.) nutrient agar (when Streptococcus hemolyticus or Diplococeus pneumoniae is used as the test organism, 5 ml. of whole blood per ml. of nutrient agar is added) and thoroughly mixed, poured into a petri plate and incubated at 37 C. The colonies resultin from unkilled organisms are counted after 24 hours of incubation.
Other special tests indicated that the results obtained by the above method were due to the germicidal action of the materials being tested and not to bacteriostatic eflects.
The extreme effectiveness of the compositions is illustrated by the results tabulated in Table I below. Included are tests using the germicidal solution alone and tests on certain of the maiterials in the presence of salt and in the presence (It is understood of 9 of peptone. The table shows the amount of silver.
in parts per million required to kill 99.5% of the The compound 5-22 is that described in Err-L ample 5 above. 8459 is a composition made-by parts by weight oi. a sodium polyphosphate (4Na2O:3P205) and 0.2867 part of silver. orthophosphate (AgaPO4), and contains 1.36% silver.
. 15-111 is a composition made by fusing together and then quenching a mixture of 0.9439 part by weight 01' silver metaphosphate (AgPOa) and 0.6034 part 01' silver pyrophosphate (Ag4P201).
iusing together and then quenching a mixture of The composition of this compound corresponds approximately to that 01' silver tetraphosphate (AgBP40l3). and has a silver content of 62.4%.
The silver preparations of this invention are very consistent and reliable in germicidal action and give results which are quite reproducible. In Table II below the results of a series oi! tests made with the silver-containing product 01' the invention designated as S-69, describedabove,
under as nearly identical conditions as' it was possible to maintain are given. In each test a series of concentrations of the germicide was tested and from .the results there were selected those concentrations which gave a 99.5% reduc- "*'tion ih the bacterial population of E. coli in the time shown, the results being expressed in terms oi. parts per million of silver. It will be noted that the results obtained are almost identical for each test, an unusual observation for a silver germicide.
3.5 1.0 min. min.
As previously pointed out the compositions of the invention are well adapted romise in germicidal detergents. One of the requirements for such uses is compatibility with the common detergent materials; another, compatibility or. effectiveness in the conditions under which such detergents are commonly used. The glassy phosphates of the invention have these compatibilities to a marked extent. Thus they are effective over a wide range of pH, that is, may be used with neutral or alkaline materials, or even acid materials, are not inactivated in the presence of salt or organic matter, by high temperatures, etc. They may be used as ingredients in germicidal v 1 v tive at high temperatures, etc. 7 Typical germicidal detergents included withinthe scope oi! the invention which are effective as detergents and also eflective germicidally in the concentrations in which the detergents are used, for example, in 1% or more dilute solution, are shown in the following examples.
EXAMPLE 12' 27% Nacconol NR (a proprietary product,being a sodium alkyl benzene sulfonate the alkyl sidechain of which is derived from a kerosene ir'action containing'hydrocarbons having an average carbon vcontent or at least 12 and not more I than 16 carbon atoms per molecule) 15% bentonite 20% sodium sesquicarbonate 37% sodium chloride 1% 53-69 (a sodium silver polyphosphate contain- 1ng.1.36% silver, described above) The total composition contains 0.0186% silver.
Whensuch a detergent composition is used in a 1% solution the silver is present in 1.36 P. P. M. Such a wash solution has a pH of 9.3 and is highly germicidal, giving a 99.99% kill oi. E. colt at 40 0. in 3.5 min. (when tested according to the procedure previously described). This is suitable as a hand dishwashing compound.
EKAMPLEB' 23.5% sodium pyrophosphate 25.0% sodium bicarbonate 25.0% borax 10.0% sodium carbonate 15.0% Nacconol NB.
The total composition contains 0,0339% silver. When this detergent-composition is used in a 0.1% solution, the solution contains 0.5 P. P. M. of silver. Such a wash solution has a pH of 9.27
and ishighly germicidal, giving a 99.98% kill of E. .coli at 40 C. in 3.5 minutes (when tested according to the procedure previously described).
20% sodium polyphosphate 40% sodium metasilicate 35% sodium carbonate 5% 5-22 (a sodium silver polyphosphate containi'ng 2.26% silver described above) The total composition contains 0.113% silver. When this detergent composition is used in a 0.2% solution, the solution contains 2.3 P. P. M. of allver. When tested according to the procedure pre- 'viously described this solution gave a99.95% kill in 3% minutes at 40 C. The pH of this solution is 10. EXAMPLE 15 82% white soap flakes The total composition contains 0.245% silver. When used in a 0.1% solution, the solution contains 2.4 P. P. M. oi. silver. This 0.1% solution has a pH of 8.9 and gave a 99.99% kill of E. coli in 3.5 minutes at 40 C. (when tested according to the procedure described above).
detergents containing carbonates, silicates, chlorides, organic compounds, or inconjunction with such materials in solution, are relatively free from inactivation by organic matter. are circa- EXAMPIEIG 99% white floating soap 1% S-69 The total composition contains 0.0136% 0! silver. A 0.1% solution of the above composition'has silver-containing phosphates similarly showed scribed above, lower than that of the compositions in which the silver content ranged from a fraction of 1% to 2 or 3% but in nearly all cases addition of a'phosphate, such as a sodium polyphosphate, enhanced the activity of the glassy silver-containing phosphate with the relatively high silver contents to an extent such that it became nearly as active based on the silver content of the test solution as the compositions with the relatively low silver content.
In the following table are shownthe results obtained with a large number of glassy sodium silver phosphates. In each case, the compound tested was made by fusing together appropriate quantities of selected silver and sodium phosphates by the method described above. In the first column is shown the percentage offsilver in the compound. In the second column is shown the ratio of metal oxide, that is Ag2O+Na2O to phosphorous pentoxide. In the third and fourth columns are shown the parts per million of silver in the test solution required to kill 99.5% of the bacteria (E. coli) by the method described above in 3.5 and 7 minutes respectively.
Tuna III Gcrmicidal Activity, No. P 01A Cgent Mo IP10 P. P. M.
1. 2s 2. a 2 :2 s 2. 2e 33/1 2. 3 3 1. 01 11 5 7 10.00 20 a1. a 5. 7
Addition of a sodium polyphosphate with an NaaozPaOs ratio oi. 4:3 in quantity equivalent to 300 parts per million oi? phosphorous pentoxide to the test solution 0! the compound No. 5 decreased the quantity of silver required for the corresponding germicidal activity to 0.5 and 0.5
P. P. M. for 3% and '7 minutes respectively. A
similar addition .to the test solution of compound No. 11 reduced the concentration 01 silver required to 5 and 5-P. P. M. for 3% and 7 minutes. Addition oi the same quantity of sodium polyphosphate to the test solution of compound No. 16
reduced the concentration for the 3.5 minute kill to 0.5 P. P.,M., the concentration for the '7 minute kill remaining the same. The same addition of sodium polyphosphate to the test solution of compound No. 23 reduced the respective effective' concentrations to 1 and 1' P. P. M., while the same addition to the test solution of compound No. z-ireduced the concentrations required to 2.3 and 2.3 P. P. M.
Similar tests carried out on glassy silver phosphates containing no metal other than silver showed that .the concentration required for a phosphate with an Ag2O:P-2O5 ratio of 1.5:1 was 46% of that for a compound with a ratio oi. 1:1 and 50% of that for a compound with a ratio of 2:1 for the 3 /2 minute kill, with respectively corresponding figures of 11.5% and 100% for the 7 minute kill, illustrating the increased eil'ectiveness of the simple glassy silver phosphates in the Ag2O:P2O5 ratios between 1:1 and -2:1 as compared with the compounds corresponding to fused silver metaphosphate and fused silver pyrophosphate.
The following table gives the results of tests carried out on potassium silver phosphates, the
columns having the same significance as inTabia.
Potassium silver phosphates Gircrgiigiidal No. Per cent Ag MOIPQOI W 3. 48 ill 25 6 1. 32 1/1 6 2 1. 47 4/3 5 2 57 4/3 2 2 3. 38 1. 5/1 2 6 2. 5
Similar data are given for glassy lithium silver Tm: VI
Magnesium silver phosphate Similar data are given in the following table for glassy calcium silver phosphates.
9,010,510 a l3 I.
7 I'm: V11 Tm: XII Calcium silver phosphates I Sodium mercury silver phosphate 4s 2.14 111 so to Germicidal 5 A l 4/3 100 1 01%) Per clent MOIPO ct my 1 3.5 7' It will be noted that with the magnesium and calcium silver phosphates there is a substantial 55 2J9 L915 M 25 increase in the quantity of silver required to be 10 56 2.24 1.18 4 3 11.5 2.3 present for germicidal eflectiveness in the test used- This is mpensated certain The following table gives data for glassy sodium poses, by their desirable properties of relative er mere suver hos hate containing 22 insolubility, and non-hygroscopicity, which make gg and $3 g them of value for purposes referred to above.
The following table gives similar data with m resfit to glassy silver sodium magnesium phossodium copper mercury silver phosphate pha TABLE V111 Per Cent Per Ccntl 1 HE 011 Silver sodium magnesium phosphates s1 2.13 1. 87 2.20 4 3 2.5 1
. 0 mil 1am 4 Per cent cent Xctitfity The following table gives data for glassy sodium Ag Mg MO/PIQ manganese silver phosphate.
i 7! TABLE 3.54 0,10 1/1 100 50 Sodium manganese silver phosphate 1. 55 1.00 1/1 so 10 2.3 1.51 41s 2 2 1. 97 6.57 4 3 20 s Pei-Cent .Mn
Again it will be noted thatin general the activ- $1 22 3 2 Z 3; ity is less than it is in the simple sodium phos- 0 93 5 7 2.3
phates, a factor which for certain uses is offset I p by the considerations outlined above. 1 I Team XV The following table gives similar data for a glassy sodium barium silver phosphate containsodium saver phosphate ing 12% g '40 Percent TABLE I)! I P Fe Sodium barium silver phosphate 61 .88 420 4 3 2.6 ,2.s a2 2.1a 3.36 4 3 5.7 y 2.3
. 4 i L36 4/3 5 The following table gives similar data for a glassy sodium nickel silver phosphate containing nickel. v I The following table gives similar data for a TABLE XVI glassy potassium calcium silver phosphate contaming calcium. Sodium nickel silver phosphate TABLI X Per Cent Ni Potassium calcium silver phosphate The following table gives similar data for a glassy sodium cerium silver phosphate, containing 5.6 The following table gives similar data for a of cerium TABLE XVII glassy sodium copper silver phosphate.
Sodium cerium silver phosphate Tun: XI
. Germicidal Sodium copper silver phosphate 65 Per Cent Ag Memo. w. I 3.55 7' Percent 53 1.82 218 '4/3 5 s 54 From the foregoing it is obvious that not only do the complex glassy phosphates of silver and alkali metals have unexpected high germicidal The followingtable gives similar data for a activity but these properties are sharedby other glassy sodium mercury silver phosphate. silver-containing complex glassy phosphates.
These glassy silver phosphates may be used for germicidal purposes in a .number of ways according to the particular need or purpose at hand. The variety of compo'sitons available, each I with good germicidal properties, but with controlled diiferences in respect. to other properties such as pfi solubility, etc.,-make these mate rials adaptable to many different uses.
When usedfor germicidal detergent purposes these products may be used in a number of ways.
- For instance, these silver phosphates or solutions thereof may be added to solutions of detergents at the timeof use. This enables one to use his favorite detergent and at will make itssolution germicidal by adding to the wash solution the prop r proportion of a selected silver phosphate.
Or one may mix the dry powdered or granular glassy silver phosphate with the desired detergent composition to provide a complete germicidal detergent composition ready for use, as illustrated in Examples 12, 13, and 14. The powdered glassy silver-containing phosphate also may be added to soap in the crutch'ing operation to provide a prodnot of composition such as is illustrated in Example'16. Thus these materials have the distinct advantage of being usable in many diflerentways.
An important feature of my silver germicides is the fact that they are effective against both gram positive and gram negative organisms. This is not generally the case with other germicides. Many germlcides are effective against either gram positive or gram negative organisms, but not against both.
I have found compositions of the invention to be active against the following gram positive organisms commonly used in determining germicidal activity:
Staphylococcus aureus Streptococcus hemolyticus Diplococcus pneumonia Corynebacterium diptheriae as well as the following gram negative organisms also commonly used in determining germicidal activity:
Eshcherichia coli Eberthella typhosus Salmonella paratyphi Shiqella dipenteriae (Flexner) My silver containing polyphosphates have been found not only to have extraordinary bactericidal properties, based on silver content, but it has also been shown that the inclusion of silver in another polyphosphate improves their properties. The solubility of the resulting complexes may be regulated by varying the proportions of the metals.
greater variety of conditions.
In accordance with the patent statutes, I have described the principles of composition of my silver-containing glassy systems, and while I have endeavored to set forth the best embodiments thereof, I desire to have it understood that obvious changes may be made within the scope of the following claims without departing from the spirit of my invention.
' micidal properties to the material when dissolved in water, said silver content not exceeding 5%.
2. A product as in claim 1 in which the remaining metal content is alkali metal.
3. A product as in claim 1, in which the remaining metal content is sodium.
4. A germicidal detergent composition which consists essentially of a water soluble soap and a minor proportion of a glassy phosphate having a metal oxide to phosphorous pentoxide ratio of 1 :1 to 2:1 and having a silver content effective to impartgermicidal properties to said glassy phosphate when dissolved in water, said silver content not exceeding 5%.
5. A composition as in claim 4 in which the remaining metal content of the glassy phosphate is sodium.
6. A germicidal detergent composition which consists essentially of an inorganic alkaline de=' tergent sodium salt and a minor proportion of a glassy phosphate having a metal oxide to phosphorous pentoxide ratio of 1:1 to 2:1 and having a silver content effective to impart germicidal properties to said glassy phosphate when dissolved in water, said silver content not exceeding 5%.
7. A composition as in c1aim.6 in which the remaining metal content of the glassy phosphate is sodium.
8: A germicidal detergent composition which consists essentially of a detergent and a minbr proportion of a glassy phosphate having a metal oxide to phosphorous pentoxide ratio of 1:1 to 2:1 and having a silver content effective to impart germicidal properties to said glassy phosphate when dissolved in water but not exceeding 5%, said detergent being composed of an inorganic alkaline detergent sodium salt and a sodium alkyl benzene sulfonate the alkyl group of which has from 12 to 16 carbon atoms.
9. A'composition as in claim 8 in which the remaining metal content of the glassy phosphate is sodium.-
ELWYN E. MENDENHAIL.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 2,174,614. Bornemann; Oct. 3, 1939 2,209,129 Menzele et al July 23, 1940 2,235,955 Williams Mar. 25, 1941 2,360,269 ,Partansky Oct. 10, 1944 2,365,489 Partridge Dec. 19, 1944 2,370,472 King Feb. 27, 1945 FOREIGN PATENTS Number Country Date 395,572 Great Britain July 20, 1933 OTHER REFERENCES Comp. Treatise on Inorganic and Theoretical Chemistry, Mellor, vol. III (1923), pp. 488-490.