US5073382A

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United States Patent 119 [11] Patent Number: 5,073,382
Antelman [45] Date of Patent: Dec. 17, 1991
[54] DIVALENT SILVER ALKALINE [56] References Cited
BACTERICIDE COMPOSITIONS U.S. PATENT DOCUMENTS
4,055,655 10/1977 M: H. 4,
[75] Inventor: Marvin S. Antelman, Rehovot, Israel tosses 5/1978 Franke ot a pavers
5,017,295 5/1991 Antelman .. 210/764
[73] Assignee: N, Jonas & Co., Inc., Bensalem, Pa. Primary Examiner—Stanley S. Silverman
Assistant Examiner—Neil M. McCarthy
[21] Appl. No.: 697,791 Attorney, Agent, or Firm—Salter & Michaelson
[57] ABSTRACT
[22] Filed: May 9, 1991 Solid alkaline bactericidal compositions are disclosed
suitable for compounding alkaline end products such as
(51) C02F 1/50 food and dairy cleaners and surgical scrubbing soaps,
[52] U.S. Cl. . 424/604; 424/601; formed by the neutralization of acid stabilized inorganic
424/60 514/495; 422/19; 422/28; divalent silver complexes and capable of effecting 100%
210/764; 210/169 kills upon cultures of anaerobic bacteria colonies of
[58] Field of Search ... 210/764, 169: 422/19, 100K /cc. within 5 minutes.

422/28, 424/618, 601, 602, 604; 514/495;
423/42

1 Claim, No Drawings

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5,073,382

1

DIVALENT SILVER ALKALINE BACTERICIDE
COMPOSITIONS

BACKGROUND OF THE INVENTION

The present invention relates to the preparation of
alkaline divalent silver (Ag(II)) bactericidal composi-
tions. Said compositions are useful for a variety of appli-
cations ranging from water treatment to compounding
surgical soaps. More particularly, this invention is con-
cerned with changing bactericidally active Ag(II) com-
plexes in acid solutions to stable alkaline compositions
without destroying Ag(II) ion capabilities of the result-
ing composition, for it is well known that Ag(II) ions
are favored in acid solutions in contradistinction to
alkaline solutions. Said Ag(II) acid complexes comprise
the subject matter of the inventor's U.S. Pat. No.
5,017,295 entitled Divalent Silver Bactericides for
Water Treatment. Said bactericides failed to act in their
sanitizing capacity when subjected to elevated pH.
Furthermore, there was a need to be able to apply these
compositions to a variety of conditions where an alka-
line pH is essential, such as the aforementioned surgical
soaps, disinfectant laundry detergents, dairy and food
processing plant cleaners, etc. It was found that a spe-
cial form of material called puffed borax was capable of
converting said Ag(H) complexes into viable alkaline
bactericides.

OBJECT OF THE INVENTION

The object of this invention is to provide an alkaline
divalent silver bactericidal composition which will be
compatible with alkaline formulations and still retain its
sanitizing capabilities.

SUMMARY OF THE INVENTION

Ag(II) alkaline bactericidal compositions were pre-
pared by mixing various ratios of Ag(II) complex acid
liquid bactericidal compositions with puffed borax, said
borax being a special low-bulk density, high-surface
grade of tetrasodium borate manufactured by the
McGean Corporation. The compositions, which varied
in alkalinity. depending on the material ratios, were
evaluated to see whether they exhibited bactericidal
action. The bactericidal efficacy of the compositions
was evaluated on E. Coli bacteria following a demand-
ing protocol of the EPA, AOAC 15th 1990:965:13.
Although it is possible that certain compositions may
have qualified ordinarily as bactericides, our criteria
demanded that only those compositions capable of kill-
ing 100K /cc cultures completely, i.e., 100% kills within
5 minutes, be considered effective for our purposes,
because my intention was to be able to formulate a
favorable composition into products such as surgical
scrubbing soaps, where instant sanitizing effects are
demanded of the resulting product.

The compositions were evaluated in the presence of
10 PPM of potassium monopersulfate as supplied by the
duPont Company under its registered trademark Ox-
one, which tested nonbactericidal in the protocol, but
which aids in the stabilization of the divalent state of

5

5

25

30

35

60

65

2

silver. Evaluations were conducted over the alkaline
PH range of 9-11. Potassium or sodium hydroxide was
used for pH adjustments, although the end products
desired are intrinsically higher than a pH of 9.

Other objects and features of the present invention
will become apparent to those skilled in the art when
the present invention is considered in view of the ac-
companying example.

DESCRIPTION OF THE PREFERRED
EMBODIMENT

The following example is given to illustrate the pre-
ferred embodiment of my invention:

A solution of Ag(II) phosphate complex was pre-
pared according to the following procedure. 1.7 grams
of silver nitrate were added to a preheated solution of a
mixture of 2.4 grams each of sodium hydroxide and
potassium peroxydisulfate dissolved in 50 cc. of distilled
water. The preheated solution was maintained at 85
degrees C. After the addition of the nitrate, the temper-
ature rose and was maintained at 90 degrees C. for 15
minutes. The solution was then allowed to cool to 50
degrees C. Eighteen cc. of 85% phosphoric acid were
then added to the solution. The temperature rose be-
cause of the exothermic reaction to 65 degrees C. After
the resulting solution had cooled, distilled water was
added to give a total final volume of 75 cc.

One cubic centimeter of the resulting Ag(II) solution
was intimately mixed with 6.5 grams of puffed borax.
There was heat released as this mixture was com-
pounded. The resulting product was a hard mass which
had a tan appearance. The resulting mass was crushed in
an agate mortar into a fine powder of about 200 mesh. A
solution containing 300 PPM of the resulting product
was prepared in distilled water. The silver concentra-
tion of this solution was 5.5 PPM. This powder was
evaluated as a bactericide according to the aforemen-
tioned EPA protocol. One hundred percent kills of E.
Coli were obtained after 5 minutes, in the presence of 10
PPM of Oxone. This compares with 98% kills after 5
minutes and 100% kills after 10 minutes of a solution of
the acid Ag(II) phosphate complex containing 2.0 PPM
of silver.

As this invention may be embodied in several forms
without departing from the spirit or essential character-
istics thereof, the present embodiment is therefore illus-
trative and not restrictive, since the scope of the inven-
tion is defined by the appended claims rather than by
the description preceding thém, and all changes that fall
within the metes and bounds of the claims or that form
their functional as well as conjointly cooperative equiv-
alents, are therefore intended to be embraced by these
claims.

What is claimed is:

1. A bactericidal solid which when dissolved in water
yields an alkaline solution capable of killing anaerobic
colonies of bacteria, comprising an acid stabilized solu-
tion of an inorganic complex of divalent silver which
has been neutralized by at least 40% of the total weight

of the composition with puffed borax.
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