The present invention relates to sanitary absorbent articles, such as disposable sanitary napkins, which feature a reinforced structure.
In general, sanitary absorbent articles are large-scale commercially manufactured articles used to absorb and retain bodily exudates. Such articles, which are convenient since they are economical yet disposable, include sanitary napkins, infant diapers, adult incontinence pads, and the like.
The technology surrounding sanitary absorbent articles, and particularly feminine sanitary napkins, has undergone several advances over the past few decades. One such advance was the addition of a flap projecting laterally from each longitudinal side edge of the article when the article is in a flattened state. Such flaps may be comprised of integral extensions of a material from which the article is formed or, alternatively, they may simply be comprised of additional material added to the article after its formation.
During use, the flaps are folded over the edges of the wearer's undergarment. Thus, they more firmly secure the article to the undergarment, stabilize the article within the undergarment, provide an increased absorptive area for bodily exudates, and help prevent the undergarment from becoming soiled in part by protecting the side edges of the wearer's undergarment. The flap concept has been well received in the marketplace and, as a result, articles featuring flaps of various configurations and conformations are currently available to the consumer.
Conventional wisdom on the part of both designers and consumers has to date dictated that the flaps on absorbent articles should be maximized at their area of juncture with the main body of the article in order to provide a greater area of protection against exudate leakage over the side of the article. Hence, a very common flap configuration is an isosceles (i.e. bilaterally symmetrical) trapezoidal-shaped flap having its base adjoined with the longitudinal side edge of the main body of the article and projecting in tapering fashion away therefrom to the top of the trapezoid. The size and shape of the flaps, however, may vary from article to article.
Sanitary napkins featuring flaps characterized by a width (dimension measured along the longitudinal axis of the sanitary napkin) that increases in a direction away from the main body of the napkin have also been proposed. This flap design offers a number of advantages, an important one being to securely retain the sanitary napkin to the undergarment of the wearer. Such enhanced retention is desirable because it stabilizes the sanitary napkin against the body of the wearer and thus reduces the likelihood of failure events.
One of the difficulties associated with the use of sanitary napkins employing flaps, however, is that the wearer, once the sanitary napkin has been used, will not detach the flaps from the undergarment before lifting away the sanitary napkin's main body. The tendency is to simply pull the main body while the flaps remain attached to the undergarment. This manipulation creates stress levels on the sanitary napkin at the area of juncture main body/flap and may cause the flaps to tear and separate from the main body. This is undesirable since the wearer must then remove the separated flap(s) in a subsequent operation that may cause annoyance. Moreover, the tearing of the flaps may expose the user's undergarment to bodily exudates contained in the sanitary napkin thereby soiling the same.
Considering this background, it clearly appears that there is a need in the industry to develop a feminine sanitary napkin which can better resist flap tearing.
Under a first broad aspect, the present invention provides a sanitary napkin adapted to be worn in the crotch portion of an undergarment. The sanitary napkin comprises a main body, at least one flap and a flap reinforcing element. The main body includes a fluid-permeable layer facing toward the wearer when the sanitary napkin is placed in the undergarment, a liquid-impervious layer, an absorbent system for absorbing liquid, a pair of opposite longitudinal side edges and a pair of opposite transverse side edges. The absorbent system is located between the fluid-permeable layer and the liquid-impervious layer. The flap is attached to the main body at an area of juncture, and has two sides and a distal end that is remote from the area of juncture. The flap and the main body together define a continuous contour, wherein at least a portion of the continuous contour includes a peripheral seal for joining the fluid-permeable layer and the liquid-impervious layer together. The continuous contour comprises a first segment and a second segment. The first segment extends along one of the longitudinal side edges from the area of juncture toward one of the transverse side edges and the second segment extends along one of the sides of the flap from the area of juncture toward the distal end. The flap reinforcing element spans across the area of juncture thereby bridging the main body and the flap. The flap reinforcing element has an edge portion that is co-extensive with the first segment and the second segment of the continuous contour, and a boundary that is internal to the peripheral seal.
A detailed description of preferred embodiments of the present invention is provided herein below with reference to the following drawings, in which:
a is a cross-sectional view taken along line 2a-2a of
b is a cross-sectional view of a sanitary napkin constructed in accordance with a first variant of the invention;
c is a cross-sectional view of a sanitary napkin constructed in accordance with a second variant of the invention;
d is a cross-sectional view of a sanitary napkin constructed in accordance with a third variant of the invention;
In the drawings, preferred embodiments of the invention are illustrated by way of examples. It is to be expressly understood that the description and the drawings are only for the purpose of illustration and as an aid to understanding. They are not intended to be a definition of the limits of the invention.
With reference to
The main body 22 also has two generally opposing transverse side edges 30, 32. Projecting laterally from each of the longitudinal side edges 24, 26 of the main body 22 are flaps 34, 36. The flaps 34, 36 are generally of the shape of an isosceles (i.e. bilaterally symmetrical) trapezoid, with the shorter of the two parallel sides thereof adjoining the longitudinal side edges 24, 26 of the main body 22 of the napkin 20. An imaginary transverse centerline 38 runs across the sanitary napkin 20 and intersects imaginary longitudinal centerline 28.
As shown in
The fluid-permeable cover layer 40 and the liquid-impervious barrier layer 48 are sealed together along their peripheral edges (including the flaps 34, 36) to form a peripheral seal 50, containing the absorbent system 42. The peripheral seal 50 can be realized by using any means commonly known in the art such as by gluing, crimping, pressure and/or heat-sealing, ultrasonics, and the like. Although peripheral seal 50 is shown as being continuous, the present invention also contemplates embodiments where the peripheral seal 50 is intermittent and therefore does not necessarily completely enclose the absorbent system 42. Thus, a variety of seal configurations are within the scope of this invention.
Each of the above layers will now be described in greater detail.
Fluid-Permeable Cover Layer
With reference to
Under one specific example of implementation, the fluid-permeable cover layer 40 is formed from an apertured thermoplastic film. Such films are common in the art. Because of the high porosity of such films, they accomplish the function of quickly transferring body exudate to the inner layers (i.e. the absorbent system 42) of the napkin 20.
The fluid-permeable cover layer 40 can also be made of fibrous materials, such as non-woven fibrous materials. The fluid-permeable cover layer 40 may be composed of only one type of fiber, such as polyester, or may be composed of bicomponent or conjugate fibers having a low melting point component and a high melting point component. Bicomponent fibers may be made up of a polyester core and a polyethylene sheath. The use of appropriate bicomponent materials results in a fusible non-woven fabric. Using a fusible fabric increases the ease with which the fluid-permeable cover layer 40 may be mounted to the barrier layer 48 at the peripheral seal 50.
The fibers may be selected from a variety of natural and synthetic materials such as nylon, polyester, rayon (in combination with other fibers), cotton acrylic fiber and the like, and combinations thereof. It will be evident to the person skilled in the art that a wide variety of other types of non-woven fabric materials can also be used.
Transfer Layer
Adjacent to the fluid-permeable cover layer 40 on its inner side and bonded thereto is the optional fluid transfer layer 44, that may form part of the absorbent system 42. The transfer layer 44 provides the means of receiving body fluid from the fluid-permeable cover layer 40 and holding it until the highly-dense absorbent layer 46 has an opportunity to absorb it.
The transfer layer 44 is, preferably, more dense than than the fluid-permeable cover layer 40 and has a larger proportion of smaller pores than does the latter. These attributes allow the transfer layer 44 to contain body fluid and hold it away from the outer side of the fluid-permeable cover layer 40, thereby preventing the fluid from re-wetting the fluid-permeable cover layer 40 and its surface. However, the transfer layer 44 is preferably not so dense as to prevent the passage of the fluid through the transfer layer 44 and into the underlying absorbent layer 46.
The transfer layer 44 may be composed of fibrous materials such as wood pulp, polyester, rayon, flexible foam, or the like, or combinations thereof. The transfer layer 44 may also comprise thermoplastic fibers for the purpose of stabilizing the layer and maintaining its structural integrity. The transfer layer 44 may be treated with surfactant on one or both of its sides in order to increase its wettability. However, the transfer layer 44 is generally relatively hydrophilic and may not require additional treatment. The transfer layer 44 is preferably bonded on both sides to the adjacent layers, i.e. the fluid-permeable cover layer 40 and the absorbent layer 46.
Absorbent Layer
Immediately adjacent to and bonded to the transfer layer 44 is the absorbent layer 46; the latter also forming part of the absorbent system 42. The absorbent system 42 may comprise a single layer structure or may comprise a multi-layer structure.
The absorbent layer 46 is a highly dense layer having a fine porosity. It has a large liquid-holding capacity and it is extremely retentive. Preferably, the absorbent layer 46 comprises a pulp fluff material and may optionally include other absorbent materials or non-absorbent materials such as conjugate fibers, fusible fibers, binders, sphagnum moss, superabsorbents, and the like and combinations thereof.
Liquid-Impervious Barrier Layer
Underlying the absorbent system 42 is a liquid-impervious barrier layer 48 which comprises liquid-impervious film material such as to prevent liquid that is entrapped in the absorbent layer 46 from egressing the sanitary napkin 20 and staining the wearer's undergarment. The liquid-impervious barrier layer 48 can be made of polymeric film, such as polyethylene or a polyethylene/ethylvinyl acetate (EVA), which are both inexpensive and readily available. The polymeric film is capable of fully blocking the passage of liquid or gas that may emanate from the absorbent system 42. In a variant, breathable films may be used that allow passage of gases while blocking liquid.
Flaps
Preferably, the flaps 34, 36 are comprised of integral continuous extensions of the fluid-permeable cover layer 40 and the liquid-impervious barrier layer 48. Thus, the flaps 34, 36 are dual layer structures, the upper layer being a continuous extension of the fluid-permeable cover layer 40 while the bottom layer is a continuous extension of the liquid-impervious barrier layer 48. It should be specifically understood, however, that flaps having a single layer structure also remain within the scope of the present invention.
Since both flaps 34 and 36 are identical, only flap 34 will be described herein.
As depicted in
The flaps 34, 36 and main body 22 together delineate a continuous contour 62 which includes at least two contiguous segments, namely a first segment 64 that is defined by a portion of longitudinal side edge 24, and a second segment 66 that is defined by a portion of side 60. First segment 64, more specifically, extends from the area of juncture 52 toward transverse side edge 32 while second segment 66 extends from the area of juncture 52 toward the distal end 56 of the flap. It should be noted that contiguous segments such as those described above exist at each side of each flaps 34, 36.
The sanitary napkin 20 further includes flap reinforcing elements. Various embodiments of the flap reinforcing elements will be described herein below with respect to
a show that sanitary napkin 20 comprises a pair of flap reinforcing elements 68.
As is also shown in
Although
In the specific embodiment shown in
Although
It could also be advantageous, in an embodiment where the flap reinforcing element 68 is disposed between the fluid-permeable cover layer 40 and the absorbent system 42, for the flap reinforcing element 68 to possesses fluid management attributes. For example, the flap reinforcing element 68 may be more dense than the fluid-permeable cover layer 40 and have a larger proportion of smaller pores than does the latter. In addition to reinforcing the sanitary napkin, the flap reinforcing element 68 can therefore also act as a transfer layer. However, the flap reinforcing element 68 must still provide sufficient reinforcement to the flaps 34, 36.
In order to manufacture the sanitary napkins 20 shown in
a to 2d all depict embodiments in which the flap reinforcing elements extend in a direction that is substantially parallel with the imaginary longitudinal centerline 28. Other realizations wherein the flap reinforcing element extends in a direction that is essentially parallel to the imaginary transverse centerline 38, are equally possible.
Although not shown in
In alternative embodiments where the transversely extending flap reinforcing element 72 is disposed between the liquid-impervious barrier layer 48 and the absorbent system 42 and wherein the former is made of breathable material (i.e., permeable to gases/vapors but impermeable to liquids), it could be advantageous for the flap reinforcing element 72 to comprise a material that is impermeable to both liquids and gases/vapors. Thus, enhanced protection against leaking is offered in an area that is coincident with bodily exudate discharge.
Although
The flap reinforcing elements, such as flap reinforcing elements 68, 72, 76 and 78 described above, may comprise a polymeric material, such as a polyolefin or polyester, or alternatively, may comprise a fibrous or cellulosic material. Preferably, the flap reinforcing elements 68, 72, 76 and 78 have a thickness in the range of 7×10−4 inches to 1.25×10−3 inches and have tensile strengths that are sufficient to cause the areas of juncture 52 to resist tearing when subjected to tensile forces typically applied by a user when attempting to remove the napkin from an undergarment without having previously detached the flaps.
Each of the above embodiments describe flap reinforcing elements that include a single layer. It should be expressly understood, however, that multi-layered flap reinforcing elements are also encompassed by the present invention. For example, multiple plies of material may be combined together to form a multi-layer structure, or alternatively, a single piece of material can be folded in order to form a multi-layer structure.
In the examples of implementation depicted in
Although the flap reinforcing element 74 is made from the liquid-impervious barrier layer 48, it should be expressly understood that flap reinforcing elements that are made by folding other layers of the sanitary napkin 20 are also possible. As shown in
Although various embodiments have been illustrated, this was for the purpose of describing, but not limiting, the invention. Various modifications will become apparent to those skilled in the art and are within the scope of this invention, which is defined more particularly by the attached claims.
This application claims priority to Application No. 60/526,793 filed on Dec. 4, 2003.
Number | Date | Country | |
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60526793 | Dec 2003 | US |