Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
2000-04-04
2001-05-08
Edwards, N. (Department: 1774)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S375000, C442S123000
Reexamination Certificate
active
06228491
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to textile articles possessing antimicrobial properties and a method for their preparation.
2. Description of Related Art
Textile articles which have been treated to render such articles microbicidal to microorganisms coming in contact with the article are known in the prior art. Such articles include those made from paper, fibers, woven and non-woven textiles and like fabrics which are designed for use in environments such as hospitals, food processing plants, laboratories and other areas where maintenance of germ-free conditions is essential.
For example, U.S. Pat. No. 2,791,518 discloses a method of imparting microbicidal properties to articles such as textiles by immersing the article in a first aqueous solution containing a water-soluble basic nitrogen compound (ammonia) and a monovalent silver salt soluble in said solution, followed by a second immersion in a second solution containing a second salt capable of ion exchange with the silver salt such that a monovalent silver salt precipitate is formed within the article. The formed silver precipitate is sparingly water soluble and imparts microbicidal properties to the articles so treated.
Similarly, U.S. Pat. No. 5,271,952 discloses a method of treating fibers to render them electrically conductive as well as anti-bacterial comprising immersing the fibers in a bath comprising an aqueous solution of a source of divalent copper ions, a reducing agent, sodium thiosulfate and a source of iodide ions, whereby copper iodide is adsorbed into the fibers. Similar techniques for rendering fibers conductive and/or resistant to bacteria involving the use of copper compounds are disclosed in U.S. Pat. Nos. 4,410,593 and 5,458,906.
One of the main problems associated with the use of monovalent silver compounds such as the halides, phosphates or sulfates in such applications is that they are sensitive to ultra-violet light and are thus prone to discoloration after exposure to sunlight, with a gradual loss of effectiveness of antimicrobial properties. Also, many of these compounds are soluble or slightly soluble in hot water which diminishes the antimicrobial properties after only a few launderings of reusable fabrics containing them.
Another problem with respect to the use of copper compounds as interstitially precipitated antimicrobials such as described in the above U.S. Pat. Nos. 5,271,952 and 5,458,906 is that these processes do not readily lend themselves to inclusion in textile production lines. Textile finishing lines involve processes which take minutes and cannot readily accommodate precipitations which require lengthy immersion times of sixty minutes or more.
The main object of the invention is to provide a method of treating fibers and/or configurated textile products so that anti-microbial properties are imparted to them. Another object of the invention is to incorporate into said fibers and textile products a powerful anti-microbial based on an electron active molecular crystal analogous to the molecular crystal, tetrasilver tetroxide, which has been proven one of the most powerful disinfectants known to man.
Another object of the invention is to form a multivalent cobal oxide by interstitial precipitation.
Still another object of the invention is to enable rapid mass production of anti-microbial fibers and textile products.
SUMMARY OF THE INVENTION
The invention provides a fibrous textile article containing a cobalt (II, III) oxide as an antimicrobial agent interstitially deposited within said article, said agent present in said article in an amount sufficient to impart antimicrobial properties to said article.
The invention also provides a process for imparting antimicrobial properties to a fibrous textile article comprising:
a. providing a solution containing divalent cobalt cations;
b. contacting said article with said solution for a period of time sufficient to uniformly wet said article with said solution;
c. immersing said wetted article in a bath containing a second aqueous solution containing a strong alkali and a water soluable per-acid salt oxidizer for a period of time sufficient to interstitially precipitate cobalt (II, III) oxide within said article; and
d. removing said article from said bath.
Textile articles prepared in accordance with this invention, particularly woven and non-woven fabrics, exhibit outstanding antimicrobial resistance with respect to pathogens such as bacteria, viruses, yeast and algae, are resistant to degradation upon exposure to sunlight (ultraviolet light) and maintain their excellent antimicrobial properties even after a number of launderings.
DETAILED DESCRIPTION OF THE INVENTION
Imparting anti-microbial (anti-pathogenic) properties to fiber and its derived textile products is achieved in the instant invention by interstitial precipitation of a molecular crystal compound multivalent cobalt oxide such as cobalt (II, III) oxide. Said cobalt moiety is based on concepts derived by analogy from silver (I, III) oxide which is the subject of patents by the instant inventor, e.g., U.S. Pat. No. 5,336,499. That patent describes the antipathogenic properties of silver oxide whose formula Ag
4
O
4
and mechanism of operation as a molecular device, based on a unique crystal having two monovalent silver (Ag I) ions and two trivalent silver (Ag III) ions in the molecule, have been fully described in said patent, as well as the mechanism of killing pathogens described therein being based on the differential silver electronic activity between Ag(I) and Ag(III), resulting in. electrocution of pathogens followed by binding chelation of pathogenic surfaces. By extrapolating these elucidated concepts, the instant inventor found that cobalt (II, III) oxide (Co
3
O
4
) was capable of killing pathogens in a like manner.
An antimicrobial spectrum of Ag
4
O
4
is to be found in a published article written by the instant inventor in the annual R&D issue of
Soap Cosmetics Chemical Specialties
1994, 70, 3 p. 52-59 entitled “Silver (II, III) Disinfectants”, shown in Table 1. The spectrum is based on specifications of the Association of Official Analytical Chemists (AOAC).
TABLE 1
Antimicrobial Spectrum of Ag
4
O
4
MICROORGANISM
MIC* (PPM)
Gram Negatives
Escherichia coll
10231
2.50
Escherichia coll
25254
2.50
Enterobacter cloacae
13047
2.50
Pseudomonas aeruginosa
9027
1.25-2.50
Gram positives
Bacillus subtilis
6633
5.00
Micrococcus lutena
9341
1.25-2.50
Staphylococcus aureus
0927
2.50-5.00
Staphylococcus aureus
27543
5.00
Staphylococcus epidermidis
12228
0.625
Streptococcus agalactiae
27956
1.25-5.00
Streptococcus faecium
10541
5.00
Streptococcus-pyogenes
7958
2.50
Yeast and Mold
Candida albicans
16404
2.50-5.0
Saccharomyces cerevisiae
2601
1.25
*MIC = Minimal Inhibitory Concentration.
The term “fibrous textile article” as used herein is intended to encompass a wide variety of materials including paper, natural or synthetic fibers, threads and yarns made from materials such as cotton, rayon, wool, jute, nylon, polyesters, polyacetates, polyacrylics as well as cellulosics in general. More particularly, the term refers to fibers woven into a fabric such as knitting, and non-woven fabrics or webbing used in anti-pathogenic applications such as in the medical field, hospitals, biotechnology and food and dairy processing. Exemplary textile products of this genre include bandages, gauze, bandage pads, skin patches, work clothes (both disposable and reusable), bed sheets, masks, dust cloths, safety belts, surgical gowns, ambulance blankets, stretchers, filter materials, diapers, underwear, pajamas, video display terminal screens and the like.
For some antimicrobial applications, Co
3
O
4
crystals may be deposited within the interstices of fibrous articles by simply soaking the article in an aqueous dispersion of the crystals (dimension of less than 100 Angstroms), or by combining the crystals with a pharmaceutically acceptable carrier medium and applying this composition to the fibrous article. This method
Edwards N.
Marantech Holding LLC
Pennie & Edmonds LLP
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