Patent Application
20080262456
The invention relates generally to absorbent garments, and more particularly to an absorbent garment and core having a design for enhancing fluid movement.
A number of commercially available diapers and undergarments are available for children and adults. Diapers and undergarments generally include a containment means to absorb liquids and capture solid wastes. Absorbent capacity is considered among the most important performance criteria of these products. Consumers desire products with high absorbent capacities to capture urine voids and absorb the liquid before the liquid can leak out of the product. Manufacturers are driven by consumers to select high absorbency materials, such as pulp fiber and superabsorbent polymers, to maximize the absorbent capacity of their products.
Many public swimming pools and recreational swimming areas require children to wear garments that prevent the release of fecal matter into the water. Fecal contamination of water in public pools can cause water-borne illnesses and pose a serious health risk to bathers who enter the water. Although diapers are capable of containing fecal matter, they have many drawbacks when used in pools or other play environments where water is prevalent. Diapers are primarily intended to remain dry, rather than submerged under water for a prolonged period of time. The outer material used on diapers can tear, and a tear at the absorbent core can release pulp fibers and superabsorbent polymer into the pool. Absorbent materials released from diapers are known to clog pool filters. Therefore, some facilities prohibit diapers in their pools.
The highly absorbent materials in diapers also create problems for children wearing diapers in pools. The highly absorbent core materials in diapers are purposefully designed to absorb a substantial amount of liquid. Pool water that is absorbed by the core material does not readily drain out of the core. The intake of liquid will cause the diaper to expand to several times its dry volume, while undergoing a significant increase in weight. Expansion of the diaper, often referred to as “swelling,” can alter the fit of the diaper and impede the child's ability to move in or out of water. Once the child exits the water, the diaper may sag significantly under the added weight of water. Because the water does not readily drain from the absorbent core, the diaper will remain waterlogged and wet against the child's skin, creating the potential for rashes and discomfort. Under these conditions, the waterlogged diaper must be removed, even if the child will soon return to the water.
To address the problem of swelling, product manufacturers have introduced variations of diapers called “swim diapers” that are intended to be more suited for use in swimming pools. Like conventional diapers, swim diapers have cores designed to absorb significant amounts of liquid. Liquid that is absorbed by the core material does not readily move out of the core, and the core therefore remains wet against the skin for a prolonged period. This can cause rashes and discomfort.
In view of the foregoing drawbacks, existing diaper products for young children are less than desirable for use in swimming pools and recreational areas where the diaper can be exposed to water. Therefore, there remains a need for improved swim pant products.
The drawbacks of using diapers and other prior art garments for swimming are avoided to a large extent by a swim pant having a core for enhanced fluid movement. In a first exemplary embodiment, a core has a ratio of total absorbent capacity (TAC) to total surface area (A) of the liquid receiving side of less than about 2,500 g/m2. The ratio of TAC/A may be between about 1,600 to about 2,500 g/m2. Alternatively, the ratio of TAC/A may be between about 1,700 to about 2,000 g/m2. Furthermore, the ratio of TAC/A may be between about 1,800 to about 1,900 g/m2.
The core may be formed of a plurality of hydrophobic fibers. The plurality of hydrophobic fibers may include non-woven polypropylene fiber. Alternatively, the plurality of hydrophobic fibers may include cellulose acetate fiber. The total surface area of the core may be between about 300 to about 450 cm2. Moreover, the core may have a total absorbent capacity (TAC) of between about 40 to about 80 ml H2O.
A core according to a second exemplary embodiment has a total absorbent capacity (TAC) of between about 40 to about 80 ml H2O. The core may have a ratio of total absorbent capacity (TAC) to total surface area (A) of the liquid receiving side of less than about 2,500 g/m2. Alternatively, the core may have a ratio of TAC/A of between about 1,600 to about 2,500 g/m2. The core may include a plurality of hydrophobic fibers. The plurality of hydrophobic fibers may include non-woven polypropylene fiber. Alternatively, the plurality of hydrophobic fibers may include cellulose acetate fiber. The total surface area of the core may be between about 300 to about 450 cm2. In addition, the core may have a TAC of between about 40 to about 60 ml H2O.
The foregoing summary and the following description will be more clearly understood in conjunction with the drawing figures, in which:
Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention.
Referring now to
Swim pant 10 is generally shown as it would appear in a ready-to-use condition. Waist portion 20 includes a front waist portion 22 and a rear waist portion 24. Similarly, side panels 30 each include a front side panel portion 32 and a rear side panel portion 34. In the ready-to-use condition, the front waist portion 22 adjoins the rear waist portion 24, while the front side panel portions 32 adjoin the rear side panel portions 34. Front and rear waist portions 22 and 24 collectively form a waist opening 26. To place swim pant 10 on the wearer, the wearer's feet are inserted through the waist opening, through the body of the swim pant and out each of the leg openings 40. Swim pant is then advanced up the wearer's legs to the wearer's crotch region, with the waist opening 26 secured around the wearer's waist and/or abdominal area by waist portion 20.
Each side panel 30 includes a tear seam or section 70. The tear sections 70 are formed of material that can be torn or split by hand to separate the front and rear side panel portions 32 and 34 from one another. In this configuration, tear sections 70 can be split to remove swim pant 10 from the wearer without sliding the swim pant down the wearer's legs. In the preferred embodiment, front and rear side panel portions 32 and 34 are refastenable after they are torn or split apart. For example, tear seams 70 may include one or more areas containing adhesive, hook and loop fasteners, or other refastenable connectors along or adjacent to the tear seams 70. This feature may be desirable where the swim pant will be worn and removed multiple times.
Referring now to
Referring now to
One of the advantages of swim pant 10, unlike diapers and other swim garments, is the swim pant's ability to be absorbent when needed, and dry quickly when needed. Swim pant 10 addresses the need for absorbing voids without providing the undesired water retention encountered in known swim garments. Under dry conditions, swim pant 10 acts like a diaper, with a core 100 having enough capacity to capture a void. Under wet conditions, such as when the wearer exits a swimming pool after being submerged, the core allows pool water to be released so that the core can dry. This limits the potential for skin rashes and other adverse effects.
The drying rate of a particular swim pant is dependent on several factors. Dry times are fairly subjective, and can vary based on humidity, temperature and other variables in the environment of the test location. Swim pants in accordance with the invention were submerged in water and allowed to sit at room temperature and pressure. The liquid receiving side of the cores were dry to the touch in less than 24 hours. Diaper cores that were subjected to the same testing remained water-logged and were wet to the touch after the same 24 hour period.
Drying rate and liquid retention are competing properties in a swim garment. As more and more liquid is retained in the swim garment, the longer the expected dry time will be. It has been discovered that core drying rate and liquid retention can be appropriately balanced to meet the needs of young swimmers who rely on a diaper-type product to contain bowel movements. It has further been discovered that the balance between core drying rate and liquid retention can be reflected by an index reflecting the ratio of total absorbent capacity of the core to surface area of the core. This index, referred to as the “drying index,” is summarized below as:
I
dr
=TAC/A
It has been found that a drying index Idr of between about 1,600 to about 2,500 g/m2 can provide both a fast drying rate and a sufficient absorbent capacity to meet the needs of child swimmers. Swim pants were tested in three different sizes, small “S”, medium “M”, and large “L.” All three sample swim pants were found to exhibit fast drying rates compared to diaper products. In addition, the three samples exhibited absorbent capacities that were sufficiently large to contain at least one void. Information on each of the sample swim pants is summarized in the following table.
The total absorbent capacities of all three samples were roughly equal, in the range of 70-72 g H2O. This capacity reflects or exceeds a conservative estimate of what is needed to retain most voids under dry conditions, assuming an average void of approximately 40 ml.
The length “L” of the core's liquid receiving side varies for each of the samples, with the length being a minimum with the small swim pant, and a maximum with the large swim pant. The width “W” of the core's liquid receiving side is the same in each sample. The total surface area of the liquid receiving sides of the samples varies from about 365 cm2 to about 435 cm2. The calculated drying index, Idr is largest in the small swim pant and smallest in the large swim pant.
Swim pants with values for TAC, L, W and Idr that are higher or lower than those in the above three samples may still demonstrate satisfactory performance and therefore be used in accordance with the invention. For example, total surface area can be from about 300 cm2 to about 450 cm2, or smaller or larger. Nonetheless, performance of the swim pant may diminish if the drying index is too large or too small. For example, a low drying index associated with a very low absorbent capacity can provide a fast dry time but not provide sufficient capacity to hold a void.
The TAC value for the core is preferably between about 40 to about 80 ml H2O, more preferably between about 40 to about 60 ml H2O, and still more preferably between about 40 to about 50 ml H2O. The Idr is preferably between about 1,600 to about 2,500 g/m2, more preferably between about 1,700 to about 2,000 g/m2, and still more preferably between about 1,800 to about 1,900 g/m2.
In a preferred embodiment, the core is formed of a hydrophobic fiber matrix. The selection of a hydrophobic fiber matrix in combination with a core design having a drying index Idr of between about 1,600 to about 2,500 g/m2 provides both a fast drying rate and a sufficient liquid retention capacity. Hydrophobic fiber materials, such as polypropylene or cellulose acetate, repel water so that water is naturally released from the matrix, and resists soaking into the fibers. Liquid retention is attributed in part to some liquid being trapped between fibers. Water can move or flow out of the core by air drying, or by being forced out from pressure on the core.
Although a rectangular core is shown in the Figures, the core can have any shape and geometry that provides the desired drying rate and liquid retention properties described above. For example, the core may have a square shape, circular shape, elliptical or oval shape, or any polygonal shape. The core may also have a variety of different thicknesses, although thinner cores are preferred. Moreover, the core may be constructed using a variety of known techniques, including those used in making cores for conventional diaper cores. U.S. Pat. No. 6,455,753 to Glaug et al. (“the '753 Patent”), the contents of which are incorporated by reference herein, describes a number of materials and techniques for constructing absorbent articles and cores for use in absorbent articles. The '753 Patent discusses ways to improve fluid acquisition, and uses superabsorbent polymers and other materials. High absorbency materials, such as superabsorbent polymers, are omitted from an exemplary embodiment of the swim pant illustrated in
While preferred embodiments of the invention have been shown and described herein, it will be understood that such embodiments are provided by way of example only. Numerous variations, changes and substitutions will occur to those skilled in the art without departing from the spirit of the invention. Accordingly, it is intended that the appended claims cover all such variations as fall within the spirit and scope of the invention.
