US2224890A - Detergent germicide - Google Patents

Description

Patented Dec. 17, 1940 UNITED STATES, PATENT oFFIcE 2,224,890 DETERGENT GERMICIDE Arthur L. Waugh, Chicago, Ill.

' No Drawing.

Application March 21, 1940,

Serial No. 325,179

3 Claims.

, sterilized in the daily use of physicians and nurses, can be immersed for the purpose of sterilization, including metallic instruments which are commonly forged from steel, and others which are cast or stamped from soft metal alloys, and are usually electroplated, without in any manner damaging the plating thereof or causing rusting or other corrosion of the material from which the same are made.

It is one of the objects of my invention to provide a germicide for sterilizing of pathogenic organisms and spores in a cold fluid without rust, corrosion, or loss of temper and edge, of fine cutting instruments, when such instruments are submerged in the germicidal fluid for an indefinite period of time, although there may be articles of varying compositions stored in the same receptacle immersed in such fluid.

Methods of sterilizing have been used that include the immersion in aqueous solutions of compounds that are of a character that cause rust or corrosion of metals, are toxic, and not sufliciently volatile to quickly evaporate. During the slow drying of such solutions rust is formed on fine cutting edges, thus impairing the quality of delicate and expensive instruments, and if the solutions are used in concentration sufficient for rapid disinfecting, damage to the metal is increased.

My invention provides not only a means for sterilizing surgical and diagnostic instruments thoroughly and promptly, but also detergent means for cleaning the same, and a means of storing the same indefinitely in a safe and handy 'manner. The germicidal agent in my invention has been selected with particular reference to reaction with the entire group of metals which it is employed to treat. It is not only important to select a reliable germicidal agent in providing a germicidal detergent fluid, such as forms the subject matter of my invention, but it is'also important that a vehicle be used for this germicidal agent that will not cause rust or corrosion, and which will reach the most remote crevices of the instruments, so as to carry the germicidal agent into the most remote crevices. In my invention I have provided a vehicle for the germicidal agent, which prevents rust and corrosion, has a low surface tension and is an exceptional solvent for grease.

As a result, my germicidal fluid spreads rapidly and thoroughly penetrates the recesses and dissolves the grease that is on the instruments from the factory, or which has accumulated from contact with human tissues in use. A surface that is free from tissue and fat is more readily and completely sterilizable, tissues and fat act as protective coatings the action of germicides, generally due because against to their aqueous nature and to the fact that many of such germicides precipitate albumin, therebyholding the spores unharmed in a capsular formation.

It is a particular purpose of my invention to provide a germicidal fluid that carries action in four stages; first, penetration;

out its second,

dissolution of tissues and fat; third, sterilization; fourth, preservation in a sterilized condition. My

germicidal fluid is colorless and stainless.

In my improved germicidal fluid I utilize formaldehyde as the germicidal agent, and utilize solvents in conjunction therewith, that. also act as inhibiting agents to prevent rust and corrosion, without the use of any foreign substances that do not have anysolvent or germicidal action, accomplishing this by the use of methanol and acetone as solvents in my germicidal fluid. '1 have discovered that it is an error to presume that it is necessary to use a substance th at is inert for germicidal or sterilizing purposes to inhibit polymerization of the formaldehyde. Also the belief previously current that if the amount of water in a solution containing formaldehyde is substantially greater than 10% or 15% the eiiiciency of the solution in preventing c orrosion is apt to be impaired, is in error, as this does not apply to a concentrated solution, such as I have invented, in which there is no ethyl alcohol,

but only methyl alcohol, formaldehyde, water and acetone.

It has been found that in such soluout showing any rusting or corrosion.

Other objects and advantages of my invention will appear as the description thereof proceeds.

I desire to have it understood, however,

that I do not intend to limit myself to the particular details described, except as defined in the claims.

In making my improved germicidal detergent Per cent Formaldehyde 16 Acetone Methanol 20 Water 24 It has been found by actual test that this solution can have steel blades of substantially the composition of carbon steel razor blades immersed therein for at least seventy-five days without in any manner causing any discoloration, rust or corrosion in the blades, or along the cutting edge thereof.

The above referred to composition provides a germicidal liquid in which instruments and other articles that are to be sterilized, are kept from the air, excluding atmospheric oxygen, said solution acting on the same to dissolve the fats and other greases therefrom, and carrying the germicide into all the crevices of the said instruments or other articles that are to be sterilized. In the composition described above, a safe margin is left between the maximum amount of water, which the liquid will absorb without injury. to the instruments, and the actual amount of water present in the composition. Thus the fluid is capable of taking up considerable water from the instruments, which has adhered to them 40 through use, without danger of corrosion. Also the formaldehyde is rendered more stable by the methanol, and both the methanol and acetone contain no appreciable amounts of water and are excellent solvents for fats. The tend- 5 ency is for the formaldehyde to break up into certain of its polymers, and this is prevented by the addition of the methanol or methyl alcohol. The use of the methyl alcohol or methanol in the solution not only has the advantage of lessening the possibility of polymerization of the formaldehyde, but also lessens the amount of water in the composition from that which would otherwise be present, if some othersolvent were utilized.

Of course, the exact-percentages given for the solution above set forth are preferred, but these proportions can be varied, from the exact percentages given, a substantial amount, as long as these are kept within the approximate proportions stated. The acetone and methanol can also be varied from the percentages given above by one or two per cent, or even a little bit more than that, without any undesirable effects being produced and without losing any of the efl'ective- Per cent Formaldehyde 16 Acetone 20 Methanol 40 15 Water 24 The relative proportions of acetone and methanol can be varied between the limits given in the two examples above set forth and all the detergent and germicidal advantages thereof obtained, without any rusting or corrosion of the steel of the cutting edges of fine surgical instruments resulting.

This highly efiective germicidal liquid contains a very high percentage of formaldehyde, as will be obvious from the percentages pointed out above. Inasmuch as hospitals and similar institutions can purchase U. S. P. ethyl alcohol tax free, such can be added to the germicidal composition ofmy invention as set forth herein, in the proportions of one part of the germicidal solution to three parts of ethyl alcohol. As long as the germicidal solution is diluted with not more than three parts of ethyl alcohol to one part of the solution, the content of water in the final product will be such that in the presence of the acetone and methanol that exists therein, the water content will be insufficient to prevent further taking up of water by the diluted germicidal liquid, and rusting, corrosion and other undesirable chemical action on the cutting edges, and other parts of blades, and other surgical instruments, will be avoided.

What I claim is:

1. A liquid detergent germicidal composition containing approximately four parts formaldehyde, six parts water and fifteen parts of a mixture of solvents consisting of methanol and acetone, said solvent mixture containing from onehalf as much to twice as much methanol as acetone.

2. A liquid germicidal detergent composition for sterilizing articles immersed therein, containing formaldehyde, acetone, methanol and water in substantially the proportion of four parts formaldehyde to ten parts acetone, five parts methanol and six parts water.

3. A liquid detergent germicide composition containing formaldehyde, acetone, methanol, and water in substantially the proportion of four parts, formaldehyde to five part-s acetone, ten parts methanol and six parts water.

ARTHUR L. WAUGH.