US3536442A - Method of manufacturing an autosterile,silver impregnated,keratin containing article - Google Patents

Description

United States Patent 3,536 442 METHOD OF MANUFACTURING AN AUTO- STERILE, SILVER IMPREGNATED, KERA- TIN CONTAINING ARTICLE Robert Brun, Geneva, Switzerland, assignor to Semi S.A., Geneva, Switzerland, a corporation of Switzerland No Drawing. Filed Jan. 26, 1967, Ser. No. 611,811 Claims priority, application Switzerland, Feb. 1, 1966, 1,402/66 Int. Cl. D06m 3/06, 3/08, 3/10 U.S. Cl. 8127.5 2 Claims ABSTRACT OF THE DISCLOSURE An autosterile article having permanent bactericidal properties and containing a metal in the divided state, colloidal or ionic, such as silver, bismuth, copper or mercury.

A method for treating said article by immersion in a solution containing said metal.

It has already been proposed to confer bactericidal properties to various objects, in particular to tooth brushes and to fabrics adapted to be employed as dressings.

However, up to the present it has not been possible to obtain a lasting bactericidal action, and the objects treated lost their bactericidal quality after relatively short use.

The invention has for object an autosterile article, characterized in that it contains or carries a metal in a divided state, colloidal or ionic, preventing the development of bacteria, fungoid growths and mildew and rendering the article autosterile and autodeodorized.

The invention also relates to a method for the production of this article, characterized in that one treats the article by immersion in a solution containing said agent.

The articles may be composed of various materials, for example natural or synthetic fibres or hairs, plastic materials, natural or synthetic leather, paper, rubber, ceramics, wood, metals or other substances of animal, vegetable, mineral or synthetic origin.

The articles to which this method may be applied are all those which, in a direct or indirect manner, may enter into contact with man or animal, for example hair brushes, tooth brushes, nail brushes, beard brushes, gloves and toilet linen, natural or synthetic sponges, clothing, underclothing, or parts thereof, handkerchiefs, articles for private hygiene, or dressings, stockings, socks, linings or inner soles of shoes, articles serving for packing or adapted to contain food, cosmetic or pharmaceutical products, a

and all articles and instruments adapted to be in contact temporarily or permanently with the skin or with the mucous membranes of man or animal.

The agent may be included in the material which will serve for the manufacture of the article or fixed afterwards, according as to whether the material employed will be synthetic or natural.

This agent is a metal in the divided state, colloidal or ionic, which has anti-microbic properties and must be fixed in such a manner that it remains or becomes prac tically insoluble, whatever be its definitive chemical or physical structure. The metal may be, for example, silver, bismuth, copper, mercury, etc.

The fixation of the metallic ions is effected, preferably, by immersion in a solution of salts of these metals, then by transformation into metallic oxide or hydroxide and reduction to a finely divided metal by a chemical or physico-chemical process. When the agent must be incorporated in a synthetic material, it may be incorporated directly in the form of the finely divided metal (precipitated or colloidal).

In order to allow of better penetration or to cause to appear reactive chemical or physical functions in the 3,536,442 Patented Oct. '27, 1970 material constituting the article, such as the hairs of a brush for example, they may be subjected to a pretreatment, for example by immersing them in solutions of ammonium thioglycolate, sodium laurylsulphate, sodium sulphide, tannin, chromium or aluminum salts, etc.

In the case of the action of ammoniacal silver nitrate on the keratin of the hair, it is established that there is not only absorption of the silver salt, but fixation of this metal and formation of an insoluble new compound which has been called silver keratinate. Silver ion fixes on electronegative groups, that is, for example, the sulphydrile and carboxylic functions of keratin, then when these functions are saturated, it is absorbed.

Thus, when 1 gr. of hairs is placed in contact, during 24 hours, with a solution containing about mg. of silver nitrate (in the form of the ammoniacal complex), all the silver ions are fixed and there do not remain any in the solution. When this critical point has been reached, one observes an absorption in equilibrium with the silver ion concentration of the solution.

Examples for carrying out the method according to the invention:

EXAMPLE I Treatment of brush hairs 100 gr. of hairs are immersed in 1 litre of an aqueous solution of sodium laurylsulphate at 10% during one hour at the temperature of 50 C., then in 1 litre of a solution of silver nitrate at 2% at the temperature of 20 C. One removes the air by passing under reduced pressure during one minute. The hairs are left in the silver nitrate solution for 24 hours while slightly stirring the solution, then the hairs are treated by 1 litre of caustic soda n/ 10 for 5 minutes, and then by 1 litre of formaldehyde in solution at 2.5% for 1 hour. The hairs are then washed with running water accompanied by very strong stirring until elimination of the particles which do not strongly adhere to the hairs.

EXAMPLE II Treatment of brush hairs 100 gr. of hairs are immersed at ordinary temperature in 2.5 litres of the following solution: 10 gr. of silver nitrate, 22 gr. of ammonium hydroxide (15% NH;,), 968 gr. of distilled water. The included air is removed by rapid passing at reduced pressure and the hairs left in the solution for 24 hours While slightly stirring. The hairs are then treated with 2.5 litres of caustic soda n/10 for 5 minutes, then with 2.5 litres of formaldehyde in solution at 2.5% for one hour. The hairs are then Washed with running water with very strong stirring until elimination of the particles which do not strongly adhere to the hairs.

Whereas in Example I, the hairs have been subjected to pretreatment in a first solution, a single treatment is applied thereto in Example II.

EXAMPLE III Treatment of a cotton fabric The fabric is immersed in a sufficient quantity of an aqueous solution of silver nitrate at 2% containing 0.2% of a non ionic surface active agent, then wrung and dried. It is then immersed in an aqueous solution containing 0.3 of hydrogen peroxide and 4% of caustic soda, and left for 15 minutes in this bath.

I claim: A

1. A method of manufacturing an autosterile keratin containing article in which silver is made to penetrate the keratin so as to prevent the formation of bacteria on said article and thereby render the article autosterile which method comprises:

first immersing said article into a heated solution containing sodium laurylsulfate;

thereafter immersing said keratin containing article in a solution containing a soluble salt of silver; then, after the second immersion, transforming the metal on said article into a metallic hydroxide by the action of an alkali solution thereon; and subsequently reducing the hydroxide to metal by the action of formaldehyde so as to obtain a metallic silver dispersion through the substance of the article. 2. A method of manufacturing an autosterile keratin containing article in which silver is made to penetrate the keratin to be made autosterile, comprising:

first immersing said article into a heated solution containing sodium laurylsulfate; thereafter immersing said article in a solution containing a soluble salt of silver; then, after the second immersion, transforming the metal on said article into a metallic oxide by the action of an alkali solution thereof; and

subsequently reducing the oxide to metal by the action of formaldehyde so as to obtain a metallic silver dispersion through the substance of the article.

References Cited UNITED STATES PATENTS 2,304,478 12/1942 Rosenzweig 8127.5 2,459,896 1/1949 Schwarz 1l7138.5 3,380,848 4/1968 Horowitz 117l38.5 XR

GEORGE F. LESMES, Primary Examiner J. R. MILLER, Assistant Examiner US. Cl. X.R.