Surgery – Means and methods for collecting body fluids or waste material – Absorbent pad for external or internal application and...
Reexamination Certificate
1999-12-28
2002-08-13
Weiss, John G. (Department: 3761)
Surgery
Means and methods for collecting body fluids or waste material
Absorbent pad for external or internal application and...
C424S076210, C424S076600, C424S443000, C514S058000
Reexamination Certificate
active
06433243
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to chemical compounds and blends which control odor and impart surface wetting properties to water-permeable porous layer materials. In particular, the invention relates to water-permeable porous layer materials treated with these dual purpose chemical compounds and blends.
BACKGROUND OF THE INVENTION
Water-permeable nonwoven fabrics, porous films, open-celled foams, and other layer materials and their manufacture have been the subject of extensive development resulting in a wide variety of materials for numerous applications. For example, nonwovens of light basis weight and open structure are used in personal care items such as disposable diapers as liner fabrics that provide dry skin contact but readily transmit fluids to more absorbent materials which may also be nonwovens of a different composition and/or structure. Nonwovens of heavier weights may be designed with pore structures making them suitable for filtration, absorbent and barrier applications such as wrappers for items to be sterilized, wipers or protective garments for medical, veterinary or industrial uses. Even heavier weight nonwovens have been developed for recreational, agricultural and construction uses. Water-permeable porous thermoplastic films are also employed in some of these applications, and may be combined with nonwoven webs. Open-celled foams are also useful in some applications.
It is not always possible to efficiently produce a porous, water-permeable layer material having all the desired properties as formed, and it is frequently necessary to treat the material with a surfactant to improve or alter surface properties such as wettability by one or more fluids, repellency to one or more fluids, electrostatic characteristics, conductivity, and softness, to name just a few examples. Conventional surfactant treatments involve steps such as dipping the substrate in a treatment bath, coating or spraying the substrate with the treatment composition, and printing the substrate with the treatment composition. For cost and other reasons it is usually desired to use the minimum amount of treatment composition that will produce the desired effect with an acceptable degree of uniformity.
For many thermoplastic layer material end use applications, it is desirable to reduce, prevent, or eliminate odors. For diapers and other incontinence products, it is desirable to reduce or eliminate the odor of ammonia which is present in urine. For feminine hygiene products, it is desirable to reduce or eliminate the odor of triethylamine. Other common odor-producing substances include isovaleric acid, dimethyl disulfide, and dimethyl trisulfide.
Odor control agents include odor inhibitors, odor absorbers, and other compounds which reduce, prevent, or eliminate odors. Odor inhibitors prevent the odor from forming. For example, U.S. Pat. No. 4,273,786 to Kraskin teaches the use of an aminopolycarboxylic acid compound for inhibiting the formation of ammonia from urea in urine. Odor absorbers and adsorbers remove odor after it is formed. Examples of odor control agents that remove odor by absorption or adsorption include activated carbon, silica, and cyclodextrins.
Typical odor control agents based on cyclodextrins cannot easily be applied from aqueous solutions to water-permeable thermoplastic substrates such as polyolefin nonwoven fabrics, porous films, and open-celled foams because the surface tension of these solutions is too high to wet out the hydrophobic substrate. Personal care products such as diapers and feminine care pads typically contain polyolefin nonwoven fabrics and/or other porous thermoplastic cover layers. Therefore, typical odor control agents cannot usually be applied to the porous thermoplastic components of personal care products. Instead, these odor control agents are usually introduced as powders to the product, which has several drawbacks. For example, placement and containment of the powder in the product can be troublesome. More importantly, powders do not present optimum surface area for odor absorption due to a rather low surface to volume ratio. Therefore, more odor control agent will be needed if in powder form.
There is a need or desire for odor absorbing compounds and blends which can be applied to a water-permeable hydrophobic (e.g., thermoplastic) substrate in a liquid or solvent form, and which have enough surface wetting properties to facilitate even fluid distribution and durability.
SUMMARY OF THE INVENTION
The present invention is directed to a water-permeable porous layer material which has been treated with a surfactant-modified odor control agent. The surfactant-modified odor control agent can be prepared by blending a cyclodextrin-based odor control agent with a surfactant, or by chemically reacting a cyclodextrin-based odor control agent with a surfactant-producing compound. Surfactant-producing compounds include both surfactants, and other compounds which behave as surfactants following the chemical reaction. The surfactant-modified odor control agent can be applied to the water-permeable porous layer material using conventional internal or external application techniques for surfactants, and is preferably applied using an external application technique. The resulting treated substrate is more wettable to aqueous liquids, and absorbs odors at its surfaces.
The water-permeable porous layer material can be a hydrophobic material, made using one or more thermoplastic polymers. For instance, the porous substrate may be a thermoplastic nonwoven filament web, a porous thermoplastic film, an open-celled foam material, or a combination thereof. A thermoplastic nonwoven filament web is preferred. The treated, water-permeable porous layer material can be used in a wide variety of personal care products and medical products, and in other applications.
The surfactant-modified odor control agents can be applied to hydrophobic substrates (for example, polyolefin-based porous films, open-celled foam layers, and nonwoven webs) from an aqueous solution, because the surface tension of the solution is low enough to wet out the low surface energy substrate. For instance, coating the surfactant-modified odor control agent on the polyolefin fibers of a polyolefin nonwoven fabric will optimize the surface to volume ratio of odor control chemistry, and thus provides better odor control (e.g., odor absorption, adsorption or inhibition). Furthermore, fibers coated with a surfactant-modified odor control agent will be in direct contact with body fluids as the fluids enter and wick through the fabric components of the personal care product. This will provide optimum odor control since the odors are believed to emanate from the body fluids.
It is thus a feature and advantage of the invention to provide a treated water-permeable porous layer material having at least one surface which is more wettable to aqueous liquids than the untreated layer material, and which absorbs common odors.
It is also a feature and advantage of the invention to provide a personal care fabric or product which utilizes a treated water-permeable porous layer material that is more wettable and absorbs odors on at least one outer surface.
It is also a feature and advantage of the invention to provide a medical fabric or product which utilizes a treated water-permeable porous layer material that is more wettable and absorbs odors on at least one outer surface.
DEFINITIONS
The term “water-permeable porous layer material” refers to a material present in one or more layers, such as a film, nonwoven fabric, or open-celled foam, which is porous, and which is water-permeable due to the flow of water and other aqueous liquids, through the pores. The pores in the film or foam, or spaces between fibers or filaments in a nonwoven web, are large enough and frequent enough to permit leakage and flow of liquid water through the material. The term does not include films and other materials which block the transfer of water, or which permit the transfer only by molecular diffusion.
The term “nonwoven fabric
Liu Yuelong
Quincy, III Roger Bradshaw
Woltman Garry Roland
Bogart Michael
Kimberly--Clark Worldwide, Inc.
Pauley Petersen Kinne & Erickson
Weiss John G.
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