[0001] The present invention relates to the field of curtain and drapes and, more particularly, to a drape suitable adapted for use in a medical or other environment and having a built-in and long-lasting sanitary and/or odor-resistant characteristic.

BACKGROUND OF THE INVENTION

[0002] Curtains commonly have a variety of uses, such as window coverings in residential settings, soft doors; as area dividers; privacy partitions (e.g. privacy curtains in a healthcare environment), and the like.

[0003] Medical privacy curtains in particular are handled by numerous healthcare personnel, patients, and others. Even healthcare personnel may contact the curtain after donning gloves, which risks patient infection. For these reasons, medical privacy curtains can be subject to significant contamination by various pathogens. They further have been observed to act as vectors to transfer such pathogens from one user to the next.

[0004] Compounding this concern, the typical pathogens resident in a healthcare setting are of greater health concern than those conventionally found in the home. Patients generally have less robust immune systems, increasing their susceptibility to infection.

[0005] Of broader concern, the US Centers for Disease Control and Prevention (USCDC) estimated in 2009 that roughly 1 .7 million hospital- associated infections occur and contribute to 100,000 deaths per year. Hospital-associated infections are estimated to impose an additional US$4.5-1 1 billion in annual healthcare costs. A similar trend exists in Europe, where it is estimated that 7-10% of patients suffer hospital-acquired infections.

[0006] Attempts to reduce the occurrence of HAIs include more frequent laundering, topically applied biocide composition treatments, and disposable privacy curtains. [0007] Frequent laundering efficiently removes pathogens, but the cleaning regime fails to provide protection between cleanings. Laundering also increases facility operating costs and may require a larger inventory of privacy curtains be maintained.

[0008] Topical treatments are prone to lack of durability, particularly in the harsh chemical and temperature conditions employed in

commercial/institutional laundering processes. Moreover, topical treatments often negatively affect the textile "hand", aesthetics, and can interact unfavorably with other surface chemistries applied thereto. Surface cleaning may degrade or remove a topically applied treatment, resulting in a privacy curtain with no antimicrobial protection.

[0009] Disposable privacy curtains attempt to address the problem of microbial buildup by replacement of the contaminated article at frequent intervals. The shorter product life of a disposable privacy curtain drives up facility operating costs, imposes a burden on staff, and presents an undesirable microbial exposure risk if the replacement schedule is not followed.

[0010] Disposable articles likewise are handled and contaminated by users in the healthcare environment. Even for disposable curtains then, there remains a need to periodically decontaminate the common touch points to prevent vectoring of microbes from a first user to the curtain to a subsequent user.

[0011] Routine spraying and/or wiping with conventional sanitizers and disinfecting solutions presents the same risk of neutralization or removal of the antimicrobial surface chemistry from precisely those touch points most in need of antimicrobial protection.

[0012] Accordingly, there is a need for a curtain and particularly a low- cost, disposable privacy curtain suitable for use in a healthcare environment, constructed of a material possessing a durable antimicrobial property for the useful life of the article and without significant loss of this property by conventional cleaning procedures. DETAILED DESCRIPTION

[0013] As used herein, the terms "microbe" or "microbial" should be interpreted to encompass any of the microscopic organisms commonly studied by microbiologists. Such organisms include, but are not limited to, bacteria and fungi as well as other single-celled organisms such as mold, mildew and algae. Viral particles and other infectious agents are also included in the term microbe.

[0014] As well, "antimicrobial" and like terms should be interpreted as encompassing both microbe-killing as well as microbistatic activities. That is, it herein is considered efficacious if an antimicrobial composition reduces the number of microbes on a substrate or it the composition retards the normal rate of microbial growth.

[0015] For ease of discussion, this description uses the terms

"microbes" and "antimicrobial" to denote a broad spectrum activity (e.g.

against bacteria and fungi). When speaking of efficacy against a particular microorganism or taxonomic rank, the more focused term alternatively may be used (e.g. "antifungal" to denote efficacy against fungal growth in particular). Using the above example, it should be understood that efficacy against fungi does not in any way preclude the possibility that the same antimicrobial composition demonstrates efficacy against another class.

[0016] For example, discussion of the strong bacterial efficacy demonstrated by a disclosed embodiment should not be read to exclude that embodiment from also demonstrating antifungal activity. This method of presentation should not be interpreted as limiting the scope of the invention in any way.

[0017] Privacy curtains generally are textile articles having a woven or nonwoven construction. They may be manufactured from a number of materials, including without limitation natural fibers, synthetic fibers, natural- synthetic blends, and blends of two or more synthetic materials. [0018] Nonwoven fabrics provide specific features and/or properties, e.g. absorbent, liquid-repellent, flexible, soft, flame-retardant, launderable, use as a barrier, and sterility. One or more of these properties can be particularly desirable in privacy curtains intended for use in a healthcare environment.

[0019] In one embodiment, a privacy curtain can be constructed of a nonwoven polymeric material, such as polypropylene. A conventional construction involves the matting of polypropylene fibers into a sheet, usually by entangling the fibers mechanically, thermally or chemically.

[0020] Into the polypropylene can be incorporated one or more antimicrobial agents as described herein. The term "antimicrobial agent" as used herein is intended to encompass both specific compounds having an antimicrobial property, as well as additives which indirectly contribute to the antimicrobial functionality (e.g. by enhancing the activity of one or more antimicrobial agents in an antimicrobial composition).

[0021] A limitation of conventional organic antimicrobial additives is their susceptibility to degradation during some manufacturing processes. For instance, zinc pyrithione is poorly suited for use in an extrusion process, as the conventionally employed temperatures cause breakdown of the additive.

[0022] New obstacles and adverse effects frequently are encountered with the substitution of organic additives with metal-based antimicrobial additives. Use of silver-based salts and complexes routinely results in discoloration of the polymer (e.g., blackening, specking, streaking).

[0023] ANTIMICROBIAL AGENT

[0024] Generally, the antimicrobial agents discussed herein can be characterized as ionic metals residing in a physiologically inert silicate carrier. These types of antimicrobial agents are hygroscopic and typically are shipped in moisture-proof packaging. [0025] Exemplary antimicrobial agents suitable for use in the disclosed sanitary curtain are proprietary metal-based antimicrobial agents. The specific agent recited in the below examples is available from Microban Products Company (Huntersville, North Carolina) under the trade name Additive IB10-M.

[0026] Additive IB10-M is a silver-based antimicrobial agent in an amorphous glass carrier. This additive has a 1 .6% silver content and a particle distribution of D98 <5um and D50 <1 .8um.

[0027] Additional silver-based agents from the same vendor include Additives IB14-M and IB15-M, which differ from Additive IB10-M in silver content, glass composition and D98/D50 values.

[0028] MANUFACTURING METHODS

[0029] A first prototype nonwoven sanitary curtain was manufactured of extruded filaments.

[0030] A portion of a masterbatch containing Microban Additive IB10- M was added to unadulterated masterbatch in order to give a final concentration in the extruded filaments in parts per million (ppm) of Additive IB10-M, based on the total weight of polypropylene. The resulting filaments then were spunbond (i.e., spunlaid and then calendared onto heated rollers) to construct a nonwoven textile.

TABLE 1

Sample Tarqet Cone. Actual Aq, ppm Calc. IB10-M. DDim

Control 0 0 0

26 2.5% IB10-M 34 2125

27 2.5% IB10-M 38 2375

28 2.5% IB10-M 35 2188

29 2.5% IB10-M 30 1875

30 2.5% IB10-M 32 2000

Avg. 2.5% IB10-M 33.8 21 13

[0031] Experimental addition rates for the antimicrobial agent were 2500 ppm Additive IB10-M by weight of polypropylene. Evident from the data of TABLE 1 is the loss of additive in the finished samples compared to the target concentration. The observed lower concentration, as compared to target, is believed due to the impossibility of achieving a perfectly

homogeneous mixture of additive in the polymer, resulting in a very small portion of the manufactured nonwoven article containing the additive above the target levels and a majority of the article containing additive very slightly below the desired level.

[0032] Once this "loss" is determined for a particular manufacturing facility, one of ordinary skill in the art can set the target level such that the finished nonwoven possesses additive at the proper and efficacious concentration.

[0033] Additive IB10-M, a particulate substance with a fairly large diameter relative to the ~20um diameter filament, is surprisingly compatible with polypropylene filaments. The additive can be utilized without disrupting the structural integrity of the filaments or the hand of the finished nonwoven made therefrom, even when the average particle size of the additive is roughly one-tenth to one-fifth the diameter of the filaments.

[0034] Samples from the above-described curtains were tested for antimicrobial efficacy using the standardized protocols as described more fully hereunder.

[0035] ANTIMICROBIAL EFFICACY

[0036] The above samples were subjected to a plurality of tests to assess efficacy against microorganisms. The specific protocols and results are described more fully hereunder.

[0037] EXAMPLE 1 : QUANTITATIVE MICROBIAL REDUCTION

[0038] The testing protocol employed to evaluate antimicrobial properties of the treated and untreated samples was based on ISO 22196 (2007), an internationally recognized and standardized test method. The protocol is briefly described as an aid to the reader. A copy of the formal ISO 22196 (2007) method is readily available from International Organization for Standardization (Geneva, CH). [0039] The ISO 22196 protocol evaluates the ability of the treated article to reduce individual populations of selected bacterial strains exposed to the surface of the treated article. The results are expressed as the reductions in the number of bacteria applied to the samples as they dwell in contact over a specified period of time.

[0040] For the ISO22196 tests, the following microorganisms were used: Staphylococcus aureus ATCC 6538 (Sau) and Escherichia coli ATCC 8739 (Eco). These microorganisms constitute a fair representation of the Gram-positive and negative bacterial spectrum to which a healthcare privacy curtain would be exposed.

[0041] From each experimental textile piece, samples were identified and taken from a plurality of areas. Samples from any one area were run in triplicate, and the results averaged.

[0042] Sample test pieces were used having dimensions of approximately 50mm x 50mm x 3mm (or as close to these dimensions as practicable). For each sample carrier needed, the bottom half of a 100mm x 15mm Petri dish was placed inside a 150mm x 15mm Petri dish, with the 150mm dish lid below it as shown in FIG. 1 .

[0043] Test pieces were placed inside their dishes, and 0.1 ml of standardized test inoculum was directly applied onto the test piece (i.e., 1 -4 x 105 colony-forming units (CFU) of the test organism). Pieces of polyethylene film measuring 2.8cm x 3.5cm were used to cover each inoculum bead, with gentle pressure to ensure that the inoculum was in contact with the test surface and contained beneath the film. Care was taken to ensure excess inoculum did not leave the surface of the sample. Dish covers were replaced and the samples incubated at 37°±2°C and 75% relative humidity for 18-24 hours.

[0044] Subsequent to incubation, sample pieces were removed from their carriers, with the cover film aseptically removed so as not to lose any inoculum. For each sample, both the film and test piece were submerged in 99.9 ± 0.1 ml sterile Letheen neutralizer broth at room temperature with vigorous shaking for about one minute to ensure total and uniform

suspension of the test organisms from the film and test surface.

[0045] Preferably within 20 minutes of the recovery, 1 .0ml of each of the test organism suspensions was plated. Corresponding plates were made at a 1 /10 dilution using sterile physiological saline. The applied liquid on the plates was air-dried, and the plates then were inverted and incubated for 18-24 hours as above.

[0046] Colony-forming units on the plates were enumerated and, taking into account the dilution factor(s) applied, CFU averages were calculated. Where the number of colony forming units is likely to be high due to low kill rates (e.g. from the untreated controls), multiple serial dilutions of the neutralizer-inoculum mixture with sterile physiological saline in the order of 1 /100 or greater may be necessary prior to plating to enable proper enumeration. Accurate counting of untreated controls is critical to allow for percent reduction calculations.

[0047] The concentration of the each test organism in its inoculum separately was established by adding 0.1 ml of the inoculum to 99.9±0.1 ml of neutralizer broth, then mixing and plating 1 .0ml of a 1 /10 saline dilution in duplicate. After allowing the applied liquid on the plates to dry, the plates were inverted and incubated for 18-24 hours. Following incubation, the colony forming units (CFU) on each plate were enumerated and, taking into account the dilution made, the average number of CFU applied in 0.1 ml of the inoculum was calculated.

[0048] Reduction values are most meaningful when compared between treated materials and identical materials that are untreated.

[0049] Percent Reduction is an expression of the number of organisms killed out of every 100 organisms that are applied to the sample. For example, a 99% reduction indicates that, within the accuracy limits of the test method, only one organism out of 100 survived after the designated period of exposure to the sample. Likewise, 99.9% reduction indicates that only one organism per 1000 survived under the same conditions. [0050] Results of the ISO 22196 tests are presented below.

TABLE 2: ISO221 96, Percent Reductions (PR) Sample IB10-M, ppm Sau Eco

Control 0 na na

Avg. 2500 99.3% 98.5% [0051 ] EXAMPLE 2: QUANTITATIVE ANTIMICROBIAL EFFICACY

[0052] The testing protocol employed to evaluate antimicrobial properties of the treated and untreated samples was based on AATCC Test Method 1 00-2004, an internationally recognized and standardized test method. The protocol is briefly described as an aid to the reader. A copy of the formal TM 1 00-2004 method is readily available from the American Association of Textile Chemists and Colorists (Durham, NC, USA).

[0053] This test method provides a quantitative procedure for the evaluation of the degree of antibacterial activity. Assessment of antibacterial activity finishes on textile material is determined by the degree of

antibacterial activity intended in the use of such materials.

[0054] If only bacteriostatic activity (i.e., inhibition of multiplication) is intended, a qualitative procedure which clearly demonstrates antibacterial activity as contrasted with lack of such activity by an untreated specimen may be acceptable. However, if bactericidal activity is intended or implied, quantitative evaluation is necessary. Quantitative evaluation also provides a clearer picture for possible uses of such treated textile materials.

[0055] In general and using the sample sizes and media as described above, test microorganism is grown in liquid culture and the concentration of the test microorganism is standardized. The microbial culture then is diluted in a sterile nutritive solution, and both control and test fabric swatches are inoculated with microorganisms. The inoculation is performed such that the microbial suspension touches only the fabric.

[0056] Bacteria levels on both control and test fabrics are determined at "time zero" by elution in a large volume of neutralizing broth, followed by dilution and plating. A control is run to verify that the neutralization/elution method effectively neutralizes the antimicrobial agent in the fabric. [0057] Additional inoculated control and test fabrics are allowed to incubate undisturbed in sealed jars for 24 hours. After incubation, microbial concentrations are determined.

[0058] Reduction of microorganisms relative to initial concentrations and the control fabric is calculated. Again, reduction values are most meaningful when compared between treated materials and identical materials that are untreated. Reductions are expressed as previously described.

[0059] For the TM100 assays, Staphylococcus aureus ATCC 6538 (Sau), Escherichia coli ATCC 8739 (Eco), Klebsiella pneumonia ATCC 4352 (Kpn), Salmonella enterica ATCC 10708 (Sen), and Pseudomonas aeruginosa ATCC 13388 (Pae) were used.

[0060] Results of the TM 100 challenges are presented below. TABLE 3A: TM100, Reductions (PR)

Sample IB10-M, ppm Eco Sau Control 0 NA NA

Avg. 2500 98.6% 98.5%

TABLE 3B: TM100, Percent Reductions (PR)

Sample IB10-M, ppm Kpn Pae Sen

Control 0 NA NA NA

Avg. 2500 96.4% 97.6% 98.6%

[0061] The results show demonstrated efficacy in samples containing about 2100 ppm Additive IB10-M by weight of polypropylene. Efficacy was observed in samples containing less than 2100 ppm IB10-M (data not shown) but deemed unsatisfactory, as the previously discussed normal variations in the mixing of treated and conventional masterbatches during manufacture would be expected to result in some portions of the finished nonwoven having insufficient additive to possess efficacy.

[0062] Concentrations above about 2100 ppm Additive IB10-M also may be used, although extremely high concentrations may begin to perturb the physical characteristics of the polymer, e.g. to discolor or opacify the polymer and/or affect its tensile strength or solidity. [0063] The present disclosure and examples are focused on curtain or drape articles as exemplary embodiments incorporating an antimicrobial agent. However, a broad variety of products advantageously may be manufactured in keeping with this concept.

[0064] It will therefore be readily understood by those persons skilled in the art that the present composition and methods are susceptible of broad utility and application. Many embodiments and adaptations other than those herein described, as well as many variations, modifications and equivalent arrangements, will be apparent from or reasonably suggested to one of ordinary skill by the present disclosure and the foregoing description thereof, without departing from the substance or scope thereof.

[0065] Accordingly, while the present composition and methods have been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary and is made merely for purposes of providing a full and enabling disclosure. The foregoing disclosure is not intended or to be construed to limit or otherwise to exclude any such other embodiments, adaptations, variations,

modifications and equivalent arrangements.