Stock material or miscellaneous articles – Composite
Reexamination Certificate
1999-12-28
2002-11-12
Hardee, John (Department: 1751)
Stock material or miscellaneous articles
Composite
C442S121000
Reexamination Certificate
active
06479150
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to chemical compounds and blends which prevent or control odor and impart surface wetting properties to layer materials. In particular, the invention relates to layer materials treated with these dual purpose chemical compounds and blends.
BACKGROUND OF THE INVENTION
Nonwoven fabrics, films, 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. Films, foams, and other layer materials are also employed in some of these applications, and may be combined with nonwoven webs.
It is not always possible to efficiently produce a 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 surface 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 formed from 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, odor adsorbers, 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 cyclodextrin.
Certain odor control agents are hydrophobic, and cannot easily be applied from aqueous solutions to substrates because they do not dissolve or disperse in water. Even if these odor control agents could be applied from solution, they would not easily wet the substrate, or render its surface wettable, due to their hydrophobic nature. Examples of hydrophobic odor control agents include, without limitation, those having aromatic chemistries.
Personal care products such as diapers and feminine care pads typically contain polyolefin nonwoven fabrics. Hydrophobic odor control agents cannot usually be applied to the fabric surfaces of personal care products. These agents are usually introduced as powders or capsules to the product, resulting in several drawbacks. For example, placement and containment of the powders or capsules in the product can be troublesome. More importantly, powders and capsules 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 one of these forms.
There is a need or desire for odor-preventing and odor-absorbing compounds and blends which can be applied to a substrate (e.g., a thermoplastic or other hydrophobic 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 surfactant-modified odor control agent formed by either a) blending a hydrophobic odor control agent with a surfactant, or b) chemically reacting a hydrophobic odor control agent with a surfactant-producing compound. Surfactant-producing compounds include surfactants, and other compounds that transform the hydrophobic odor control agents into surfactants following the chemical reaction. The invention is also directed to a layer material which has been treated with the surfactant-modified odor control agent. The surfactant-modified odor control agent can be applied to the layer material using conventional internal or external application techniques, and is preferably applied using an external application technique. The resulting treated substrate is more wettable to aqueous liquids, and prevents, reduces and/or absorbs odors at its surfaces.
The substrate layer material can be a hydrophobic material, and can be a thermoplastic material made using one or more thermoplastic polymers. The layer material can be porous and water-permeable. For instance, the layer material can be a thermoplastic nonwoven filament web, a thermoplastic film, a foam layer, or a combination thereof A thermoplastic nonwoven filament web is preferred. The treated 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 or other substrates (for example, polyolefin-based films, 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, the coating of 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 provide better odor control (e.g., odor absorption, adsorption, prevention 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 surfactant-modified odor control agent having the odor control properties of a hydrophobic odor control agent, which can be applied to a substrate using solution techniques.
It is also a feature and advantage of the invention to provide a treated layer material having at least one surface which is more wettable to aqueous liquids then the untreated layer material, and which inhibits and/or absorbs common odors.
It is also a feature and advantage of the invention to provide a personal care fabric or product which utilizes the treated layer material that is more wettable, and inhibits and/or 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 the treated layer material that is more wettable, and inhibits and/or absorbs odors on at least one outer surface.
DEFINITIONS
The term “layer material” refers to a material that exists in the form of a flexible, fabric-like or paper-like material, including without limitation nonwoven filament webs and fabrics, thermoplastic films, flexible thermoplastic foam materials, and multilayer combinations including one or more of these.
The term “water-permeable porous layer material” refers to a material present
Liu Yuelong
Quincy, III Roger Bradshaw
Woltman Garry Roland
Hardee John
Pauley Petersen Kinne & Erickson
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