Gas separation – Specific media material – With coating – impregnant – or bonding agent
Reexamination Certificate
2000-01-27
2003-02-04
Simmons, David A. (Department: 1724)
Gas separation
Specific media material
With coating, impregnant, or bonding agent
C055S527000, C055SDIG005, C095S211000, C096S154000, C096S290000, C096S296000, C261S104000, C261S107000, C422S120000
Reexamination Certificate
active
06514306
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates generally to fibrous media, and more particularly to fibrous media having anti-microbial agents contained therein.
2. Discussion
Conventional filtration systems, especially those employed for air filtration in homes and automobiles, typically employ a filter element comprised of a web, mat, or sheet of filter media in order to trap and retain particulate matter entrained in an air flow that passes through the filter media. Although conventional filter media generally perform well in dry or arid environments, there are some problems associated with operation in moist or humid environments.
Specifically, if conventional air filter media are operated for extended periods of time while exposed to elevated levels of relative humidity (i.e., greater than 50%), the media can often become a source of offensive odors resulting from the microbial proliferation on the surface thereof, which is especially problematic for homeowners that have air conditioning systems located in damp basements. The microbial proliferation is due, in part, to the concentration of nutrients and water on the filter media surface.
In an effort to overcome this problem, filter manufacturers have applied various anti-microbial agents in the form of finishes and coatings to various fibrous materials, including textiles, clothing, surgical drapes, and so forth. However, virtually all of these anti-microbial finishes suffer from one or more disadvantages which severely impacts their ability to be effective for their intended purpose.
Most of the anti-microbial finishes rely on a stable anti-microbial layer covalently bound to the fiber surface so that it is “wash fast” (i.e., will not be removing during normal laundering). This approach is ineffective to overcome the present problem because it does not allow the anti-microbial agent to be liberated and freely mobile to diffuse throughout the “fouled” layer and come in contact with the bio-active layer which is typically on the very outermost surface. Basically, the bulk of the anti-microbial agent is uniformly dispersed throughout the filter media, such as on fibers located in the interior of the filter element, and is, of course, not effective in repelling the growth of microbial populations on the exterior surface of the filter element. Accordingly, the overall anti-microbial capacity is low because the microbial population never comes into contact with an appreciable amount of the anti-microbial agent at an earlier enough stage. As a result; the level of offensive odors emanating from the filter media would tend to increase over time, thus causing the consumer to discard the filter element.
Other approaches to overcoming this problem have relied on incorporating the anti-microbial agent into a resin melt and then subsequently spinning the treated resin melt into fibers. This approach requires a slow blooming of the anti-microbial agent out of the fiber before it can be effective. In addition, there is an upper limit regarding the maximum loading of anti-microbial agent which can be incorporated into the fiber without losing adversely affecting the physical properties of the fibers or the performance of the filter element. For example, high loading of anti-microbial agents may interfere with certain electret fiber filter elements.
In addition to filter manufacturers, wound management manufacturers (i.e., bandage and wound dressing manufacturers) have also shown an interest in incorporating an anti-microbial agent into various items, such as gauze wraps, adhesive bandages, and the like. These items are primarily comprised of a fibrous media, such as cotton. In a typical wound situation, various fluids are occasionally released from the wound site, including blood, serum, pus, and the like. Occasionally, these fluids come into contact with pathogens, thus permitting an infection to develop in the area of the wound. Even if these fluids are not present, airborne pathogens may penetrate the bandage (especially during periods of high relative humidity) and come into contact with the wound area, thus initiating an infection. The availability of a selectively active anti-microbial agent to prevent or arrest the development of an infection would enhance the marketability of such items.
Therefore, there exists a need for fibrous media that contains an anti-microbial agent that is capable of diffusing throughout the fibrous media so as to come into contact with the microbial population, especially during periods of relatively high humidity.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a new and improved fibrous media.
It is another object of the present invention to provide a new and improved fibrous media having an anti-microbial agent contained therein.
It is yet another object of the present invention to provide a new and improved fibrous media having an anti-microbial agent contained therein, wherein the anti-microbial agent is capable of diffusing throughout the fibrous media so as to come into contact with the microbial population, especially during periods of elevated levels of relative humidity.
In accordance with one embodiment of the present invention, a fibrous element is provided, comprising:
at least one container member; and
at least one anti-microbial agent disposed within the at least one container member;
wherein the at least one anti-microbial agent is capable of diffusing out of the at least one container member and throughout the fibrous element in response to elevated relative humidity levels in order to contact a microbial population.
In accordance with another embodiment of the present invention, a fibrous element is provided, comprising:
a fibrous mat;
at least one container member, the at least one container member being disposed within the fibrous mat; and
at least one anti-microbial agent disposed within the at least one container member;
wherein the at least one anti-microbial agent is capable of diffusing out of the at least one container member and throughout the fibrous mat in response to elevated relative humidity levels in order to contact a microbial population.
In accordance with yet another embodiment of the present invention, a fibrous element is provided, comprising:
a fibrous mat;
at least one container member, the at least one container member being disposed within the fibrous mat, the at least one container member being selected from the group consisting of an elongated fiber having multiple lobes with a longitudinally extending internal cavity including an opening from the internal cavity to the outer fiber formed between adjacent lobes, an elongated fiber having an internal longitudinally extending cavity having a longitudinally extending opening, a particulate, and combinations thereof; and
at least one anti-microbial agent disposed within the at least one container member;
wherein the at least one anti-microbial agent is capable of diffusing out of the at least one container member and throughout the fibrous mat in response to elevated relative humidity levels in order to contact a microbial population.
A more complete appreciation of the present invention and its scope can be obtained from the following brief description of the drawings, detailed description of the invention, and the appended claims.
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Jones Gordon William
Rohrbach Ronald P.
Unger Peter D.
Honeywell International , Inc.
Pham Minh-Chau T.
Simmons David A.
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