US 1993686 A
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Patented Mar. 5, 1935 UNITED STATES PATENT OFFICE PROCESS FOR THE MANUFACTURE OF DISINFECTING SOAPS Germany No Drawing.
Application September 8, 1932,
Serial No. 632,274. In Germany November 28,
Object of my invention is a process for manufacturing soaps with a disinfecting action.
Disinfectant soaps the disinfecting action of which is due to the incorporation of metallic salts such as mercury bichloride (corrosive sublimate) have been known for some time. The present invention relates to the use of silver salts in particular as the disinfecting agent.
It has been suggested already to prepare such soaps by incorporation of soluble silver salts or compounds such as (AgNH3)OH or Ag(CN)2K into the soap but experiments to that efiect did not give satisfactory results. The reason is that on the one hand soaps prepared with soluble silver compounds showed very little disinfecting efiiciency whilst on the other hand the soaps on being stored or during usage became discoloured which is highly undesirable. On account of these difliculties and disadvantages silver soaps of this description have not found any practical use.
Silver compounds which are insoluble such as silver sulfide have been employed but without any success, Since soaps prepared with them possess so small disinfecting action that they are scarcely of any practical use.
According to my new process I obtain soaps of greatest efficiency which show none of the above mentioned drawbacks by incorporating into the soap mixture silver compounds which should be neither insoluble nor soluble with great ease. By incorporating silver salts or compounds which are soluble only with difliculty into the soap mass I succeed in preparing soaps which combine with excellent disinfecting qualities the property of allowing the soap to be stored and used without being discoloured undesirably. The disinfecting action of soaps according to my invention seems to depend upon the fact that silver ions are set free or brought into solution to such an extent as are required for obtaining a satisfactory action but not to such a degree that colouring or discolouring action results therefrom.
Suitable silver compounds for obtaining the effect aimed at of yielding in combination with soap masses good disinfecting action without causing discolouration are for instance silver subhalogenides such as silver subchloride, silver subbromide, silver subthiocyanide and the like. Trials with silver compounds of this description have proved that soaps which contained these with dificulty soluble compounds had an excellent disinfecting action and were free from the disadvantage of discolouration on being used or stored.
According to a special form of carrying my invention into effect I incorporate in addition to the silver compounds of the said character, compounds or substances which contain active. oxy gen into the soaps. Such substances containing active oxygen are, for instance, sodium pyrophosphate hydrogen peroxide, alkali metal perborate such as sodium perborate and the like. The compounds or substances containing active oxygen may be incorporated into the soap mass simultaneously with the silver salts; they may also be worked into it before or after the silver salts are incorporated.
By the action of silver compounds or the silver ions set free respectively and of the substances containing active oxygen or the oxygen respectively generated therefrom combination effects may be obtained as regards the disinfecting action of the soap which exceed the sum of the actions of each single component. Besides the effect of the active oxygen itself, the presence of substances containing active oxygen seems to activate the silver compounds or the silver formed therefrom respectively with respect to their disinfecting properties and thereby increase the latter.
It is advisable during the preparation and manufacture of soaps according to my invention i. e. containing silver compounds with or without substances containing active oxygen, to avoid the presence of water as far as possible since it is well known that active oxygen containing compounds are decomposed when in contact with soaps containing water. The presence of water would therefore cause loss of oxygen and thereby decrease of its action as well as the activating effect upon the silver compounds.
Another form of carrying my invention into effect consists in the simultaneous use with the silver compounds soluble with difficulty, of metallic silver when manufacturing the soap. The silver may be employed in the form of powder, foils, leaves, tinsel or the like. The metallic silver has, also, a disinfecting efiect when it is incorporated in soap. The chance of undesirable discolouration of the soap on storage and usage Examin is diminished when silver metal is employed. In consequence by the combined incorporation of metallic silver and with difiiculty soluble silver compounds excellent disinfecting effects can be obtained which may be regulated at will by increasing the amount of the one substance in relation to the other without running the risk of discolouration, formation of spots or the like.
Furthermore, the disinfecting effect of the metallic silver to be incorporated into the soap can be enhanced by a preliminary treatment with oxidizing agents. Such agents are for instance compounds containing active oxygen or other oxidizing agents such as alkali metal permanganates. The oxidizing preliminary treatment may be effected also electrochemically, for instance in such a manner that the metallic silver for instance in the form of tinsel or the like is subjected to a superficial anodic oxidation.
The activation of the metallic silver can also as the case may be, be achieved by the incorporation into the soaps of compounds containing active oxygen.
Finally I have found that I can dispense with the silver compounds soluble with difiiculty altogether and replace them in their entirety by metallic silver advantageously in the activated form obtained by the preceding treatment with oxidizing agents.
Example 1 To the soap body prepared in the well known way about 0.5 to 1% of silver subchloride in a finely divided form is added in the crutching machine together with other cosmetics such as perfumes or the like. The addition may be effected also separately. The mixture is then worked into a uniform mass. Dyes may be added in order to improve the colour of the finished soap. The soap after it has passed the press shows uniform colour in each single piece, which is not changed by light.
Example 2 The soap is prepared in a well known manner and after it has been dried thoroughly converted into fine powder. To the fine powders thus prepared the desired amounts of silver subchloride and sodium perborate which have been passed through a sieve previously are added. The perborate has been subjected advantageously to preliminary dehydration. The quantities to be added are for instance 1.0% of silver subchloride and 1% of active oxygen in the form of perborate. After thorough mixing the powder is subjected in a suitable press to high pressure such as 100 atmospheres whereby the powder is molded into a solid piece.
Example 3 Into the composition according to Example 1 and comprising silver subchloride together with the latter 1% of silver powder is incorporated. This powder in order to increase its oligodynamic action has been activated previously by treatment with substances containing active oxygen such as hydrogen peroxide. The metallic silver can be incorporated into the soap in the form of foil, leaves, tinsel or the like in order to achieve a certain decorative effect. Instead of working it into the soap it may also be put onto the surface of the pieces. By arranging the various bits in patterns the decorative effect may be enhanced whilst at the same time the disinfecting power of the silver is made use of.
What I claim is:
1. A soap which contains silver subchloride.
2. A soap which contains a substance selected from the group consisting of silver subhalogenides and silver subthiocyanide.
3. A soap which contains a substance selected from the group consisting of silver 'subhalogenides and silver subthiocyanide, and substances free of water of crystallization containing combined hydrogen peroxide.
4. A soap which contains a substance selected from the group consisting of silver subhalogenides and silver subthiocyanide, and alkali metal perborates free of water of crystallization.
5. A soap which contains a substance selected from the group consisting of silver subhalogenides and silver subthiocyanide, and dehydrated sodium perborate.
6. A soap which contains a substance selected from the group consisting of silver subhalogenides and silver subthiocyanide, metallic silver and substances free of water of crystallization containing combined hydrogen peroxide.
'7. A soap which contains a substance selected from the group consisting of silver subhalogenides and silver subthiocyanide, activated metallic silver and substances free of water of crystallization containing combined hydrogen peroxide.
8. A soap containing metallic silver in a finely subdivided solid non-colloidal state.
9. A soap which contains metallic silver in finely subdivided solid non-colloidal state after it has been activated to increase its oligodynamic action.