Drug – bio-affecting and body treating compositions – Solid synthetic organic polymer as designated organic active... – Ion exchange resin
Reexamination Certificate
2000-09-01
2002-01-29
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Solid synthetic organic polymer as designated organic active...
Ion exchange resin
C424S618000
Reexamination Certificate
active
06342212
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to broadly defined adhesive latex formulations exhibiting antimicrobial properties. Such formulations comprise, as the only antimicrobial active ingredients, certain inorganic antimicrobial compounds, such as, preferably, metal-containing ion-exchange and/or zeolite compounds. The inventive latex formulations must also exhibit substantially uniform characteristics (such a similar viscosity and/or appearance throughout) in order to provide a functionally and aestheticially pleasing formulation for utilization within any number of applications. In order to provide such an inventive latex formulation, it has been found that compounding of all the base ingredients (polymer, antimicrobial agent, fillers) must be undertaken prior to the final thickening, step, which ultimately produces the desired latex. The specific method of producing such formulations is also encompassed within this invention.
DISCUSSION OF THE PRIOR ART
All U.S. Patents listed below are herein entirely incorporated by reference.
There has been a great deal of attention in recent years given to the hazards of bacterial contamination from potential everyday exposure. Noteworthy examples of such concern include the fatal consequences of food poisoning due to certain strains of
Eschericia coli
being found within undercooked beef in fast food restaurants; Salmonella contamination causing sicknesses from undercooked and unwashed poultry food products; and illnesses and skin infections attributed to
Staphylococcus aureus, Klebsiella pneumoniae
, yeast, and other unicellular organisms. With such an increased consumer interest in this area, manufacturers have begun introducing antimicrobial agents within various household products and articles. For instance, certain brands of polypropylene cutting boards, liquid soaps, etc., all contain antimicrobial compounds. The most popular antimicrobial for such articles is triclosan. Although the incorporation of such a compound within liquid or certain polymeric media has been relatively simple, other substrates, including the surfaces of textiles and fibers, have proven less accessible. Furthermore, triclosan includes chlorine ions which, upon dissociation, may release to the substrate surface. Such ions are potentially hazardous to humans, due to skin irritation upon contact, as well as within environmental effluents, and the like. Additionally, harmful microbes have shown, on occasion, an ability to develop an immunity to the bactericidal properties of triclosan. Also, surface treatments with triclosan have proven ineffective as well since such compounds are highly water soluble and are easily removed upon exposure to sufficient amounts of moisture and high temperatures. There thus remains a long-felt need to provide a short-and long-term effective, durable, and long-lasting antimicrobial agent for surface utilization within adhesive latex formulations. Of additional importance is the need to provide such formulations which, upon exposure to high temperature processing conditions (either in the production of or incorporation of such formulations within other applications, such as carpet backing, and the like) do not require the presence of organic bactericides which may result in the release of a certain volatile organic content (VOC) upon such high temperature processing.
One proposed latex has utilized metal ions for bactericidal properties, but also requires the presence of an organic bactericide to provide the desired level of antimicrobial activity. U.S. Pat. No. 5,736,591 to Dunn teaches the addition of certain metal ions, including copper, silver and any other Group Ib metals, as salts (such as silver nitrate, silver perchlorate, and the like) to latex formulations in combination with Such organic compounds as 2-methyl-4, 5-trimethylene-4-isothiazolin-3-one, to provide a bactericidal latex. No mention is made anywhere within this patent of the availability, much less, the capability of silver-based ion-exchange or zeolite compounds as potential antimicrobial agents. Nor is there any discussion of the ability of any such silver-based compounds providing effective antimicrobial activity without the need for any added organic bactericides.
Such specific silver-containing inorganic microbiocides (e.g., ion-exchange and/or zeolite compounds) have recently been developed and utilized as antimicrobial agents on and within a plethora of different substrates and surfaces. In particular, such microbiocides have been adapted for incorporation within plastic compositions and fibers in order to provide household and consumer products which inherently exhibit antimicrobial characteristics. Although such silver-based agents provide excellent, durable, antimicrobial properties, to date no teachings exist which teach or fairly suggest the presence of such inorganic compounds within adhesive latex fomulations. This is not surprising considering the difficulties which have been noted in attempting such an introduction of these large molecular weight, bulky, compounds within polymer latex formulations to begin with. For instance, such inorganic compounds may interfere with the desired adhesives qualities of the latex if and when such large molecules are present at the surface. One would anticipate that a large surface accumulation of such bulky compounds would reduce the potential surface-to-surface interaction required for the adhesive formulation to function properly. Furthermore, it has been found that the addition of such bulky compounds within already-compounded latex formulations is extremely difficult. The resultant composition generally exhibits discrete areas of concentrated, dark-colored, antimicrobial compound. Not only does this result in an unpleasing aesthetic appearance, but such a latex, being nonuniform in dispersion as well, may exhibit uneven adhesive properties, too. Although these problems exist, there is a desire to incorporate such silver-based inorganic antimicrobial agents within adhesive latex formulations in order to provide a regenerable, highly effective, long-lasting antimicrobial latex at, on, or within various different articles. Unfortunately, to date, no such antimicrobial adhesive latex or methods of production or use thereof have been accorded the latex industry by the pertinent prior art.
DESCRIPTION OF THE INVENTION
It is thus an object of the invention to provide a simple manner of producing an effective adhesive latex comprising, as the sole antimicrobial agent, at least one inorganic silver-based ion-exchange compound or zeolite compound. Another object of the invention is to provide an antimicrobial adhesive latex exhibiting a substantially uniform appearance and possessing no VOC content.
Accordingly, this invention encompasses an adhesive latex fomulation comprising at least one polymer constituent, at least one thickening agent (in order to provide a latex having a viscosity of, preferably, at least 4,000 cps at 25° C. and at 1 atmosphere), and at least one inorganic silver-based antimicrobial agent selected from the group consisting of silver-based ion-exchange compounds, silver-based zeolites, silver-based glasses, and any mixtures thereof, wherein said formulation does not include any VOC (due to the absence of any organic bactericide compounds, primarily). This invention also encompasses a method of producing such an antimicrobial adhesive latex formulation comprising the steps of (a) providing a polymer constituent, compounding said polymer constituent with an inorganic silver-based antimicrobial agent (as noted above) and a thickener, simultaneously, until the resultant composition exhibits a viscosity of, preferably, at least 4,000 cps at 25° C. and at 1 atmosphere.
The term adhesive latex is intended to encompass any thickened formulation of already-made polymer constituents which possesses a viscosity of at least viscosity of, preferably, at least 125,000 cps at 25° C. and at 1 atmosphere and which also exhibits an affinity for different surfaces which results in the ability to create a s
Lever John G.
Schuette Robert L.
Sellman, Jr. N. David
Fubara Blessing
Milliken & Company
Moyer Terry T.
Page Thurman K.
Parks William S.
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