Patent Application
20080082075
The features of the invention and the elements characteristic of the invention are set forth with particularity in the appended claims. The figures are for illustration purposes only and are not necessarily drawn to scale. The invention itself, however, may best be understood by reference to the detailed description which follows when taken in conjunction with the accompanying drawing in which:
The invention will next be illustrated with reference to the figures. Such figures are intended to be illustrative rather than limiting and are included herewith to facilitate the explanation of the present invention. The figures are not to scale, and are not intended to serve as engineering drawings.
Referring generally to the drawings (
In further embodiments of the present invention, methods for producing an absorbent article 100, 200, 300, 500, 600 are provided. The methods include the step of positioning or aligning an acquisition layer adjacent or substantially parallel over an absorbent layer. The absorbent layer 106, 206, 306, 506, 606 is then folded or rolled into a substantially C-shaped configuration such that a central region of the acquisition layer 108, 208, 308, 508, 608 is positioned adjacent a central-most region 1 of the absorbent layer. Other regions of the acquisition layer are positioned adjacent to the folded regions of the absorbent layer. The absorbent layer and acquisition layer are then interposed between the cover layer 102, 202, 302, 502, 602 and the barrier layer 104, 204, 304, 504, 604.
Referring now to the drawing, in which like reference numbers refer to like elements throughout the various figures that comprise the drawing,
The cover layer 102 is preferably liquid permeable in order to enable liquid to quickly and efficiently pass through the cover layer and into the acquisition layer 108. In particular, the cover layer may be selected from a variety of textile-like films and fabrics. Suitable fabrics include non-woven materials that are pervious to liquid, soft and pliable. Preferred non-woven materials include spun-bonded polypropylene, spunbonded polyethylene, and thermally bonded webs of staple fibers, preferably polypropylene shape or sheath/core bi-component fibers having a core of polyester or polypropylene and a sheath of polyethylene. To enhance the fluid control properties of the aforementioned liners, surfactants or wetting agents typified by Triton® X-100 and Triton® X-102 available from Rohm & Haas Company of Philadelphia, Pa. may be applied to the fluid receiving zones of the liner selectively, having the outer zones untreated to reduce migration of excreted fluid into the outer absorbent article regions, leading to leakage.
As further seen in
As seen with respect to the embodiment of the absorbent article 100 shown schematically in
The absorbent layer 106 is preferably made of materials including a super absorbent material, but may also be made of any suitable absorbent material, as well as combinations of different types of absorbent materials. For example, the absorbent layer 106 may be formed of a mixture of pulp fluff and super absorbent polymer (SAP) wrapped in a liquid permeable tissue wrap (not shown). Examples of SAP include polyacrylamides, polyvinyl alcohol, polyacrylates, various grafted starches, and the like. A desired super absorbent material is a cross-linked polysodium acrylate, which can be purchased from BASF Corporation of Portsmouth, Va., under the trademark ASAP® 2260. The super absorbent materials can be in various geometric forms, such as various shaped particles, fibers, foams, and layers.
The absorbent layer 106 may be of any shape, but is generally a flat rectangular sheet which is then rolled or folded into a C-shape configuration. The absorbent layer 106 is optionally a single layer or a layer formed by two or more sub-layers of absorbent material. In the C-shape configuration, the folded regions of the absorbent layer oriented towards the cover layer 102 form a natural container for holding larger volumes of liquid to be absorbed into the absorbent layer. The absorbent layer may be a single, integral absorbent structure, or can comprise a plurality of individual separate absorbent structures and/or absorbent materials that are operably assembled together. For instance, the absorbent layer may include two or more separate absorbent structures that are positioned side-by-side to the left and/or right of the central-most region or over the central-most region. The absorbent layer may also include two or more separate absorbent sublayers superposed with respect to one another. The absorbent layer may also include an air-laid non-woven web that contains super-absorbent particles and/or super-absorbent fibers, polymeric binder and cellulose pulp fibers.
In one exemplary embodiment, the absorbent core or layer is optionally sandwiched between two plies of tissue, is aligned on top (in the orientation shown in the figures) of the barrier layer 104 and adhered with construction adhesive. The tissue may typically have a basis weight of 17 gsm. Suitable tissues are available from Cellu Tissue Corporation, East Hartford, Conn. The absorbent layer 138 is typically centered along a central lengthwise direction or central axis of the absorbent article 100.
The central region of the acquisition layer 108 positioned between the central-most region of the absorbent layer 106 and cover layer 102, and other regions of the acquisition layer 108 positioned between the folded regions of the absorbent layer 106 and cover layer 102, function as an insulating layer between the absorbent layer 106 and cover layer 102. In other embodiments, it is contemplated that the central region of the acquisition layer 108 may be positioned either adjacent or in contact with the central-most region of the absorbent layer 106. Furthermore, other regions of the acquisition layer 108 may be positioned either adjacent or in contact with the folded regions of the absorbent layer 106.
As liquid penetrates the cover layer 102, the acquisition layer 108 is able to quickly absorb the liquid and transfer it to the absorbent layer 106. The acquisition layer 108 remains relatively dry even after liquid has penetrated the acquisition layer 108. The acquisition layer is generally composed of resilient fibrous webs that provide a small absorbent volume to rapidly take up liquids and then release it to the absorbent layer 106. This allows adequate time for super absorbent materials in the layer, when such super absorbent materials are optionally employed, to absorb the liquid. The thickness of the acquisition layer is preferably thin to provide the small absorbent volume and fast absorbency rate.
The acquisition layer 108 is typically composed of woven materials that are substantially nonabsorbent and hydrophobic. Suitable materials include fibrous webs and foams that may also include air-laid webs that contain polymeric binder fibers. Other suitable materials include polypropylene, polyethylene, and, preferably polypropylene sheath/core bi-component fibers having a core of polyester or polypropylene and a sheath of polyethylene. The acquisition layer 108 may be composed of any one of such materials, as well as combinations of different types of nonabsorbent materials.
As with the absorbent layer, the acquisition layer may include two or more separate acquisition structures that are positioned side-by-side or superposed with respect to one another. For instance, the acquisition layer may include two or more separate acquisition structures that are positioned side-by-side to the left and/or right of the central-most region or over the central-most region. The acquisition layer may also include two or more separate acquisition sublayers superposed with respect to one another.
The acquisition layer 108, existing as a mass of these materials, is able to accept liquids and allow passage of the liquid through its mass to be absorbed by the adjacent absorbent layer 106. Therefore, the mass of materials for the acquisition layer 108 may be absorbent, although the materials themselves are preferably not absorbent. Thus, the acquisition layer 108 which is preferably made of hydrophobic, nonabsorbent materials is able to accept large volumes of fluid into the interfiber spaces while the fibers themselves do not absorb any significant quantity of liquid. This allows the surface of the acquisition layer 108 to remain substantially or relatively dry even after liquid has penetrated the layer, and acts as an insulating layer between a relatively wet absorbent layer 106 and the wearer's skin.
As further seen in
The central region of the acquisition layer 208 is optionally positioned adjacent, yet spaced from the central-most region of the absorbent layer 206. Alternatively, the central region of the acquisition layer 208 is optionally positioned in direct contact the central-most region of the absorbent layer 206. Also, the other regions of the acquisition layer 208 are optionally positioned adjacent, or alternatively in direct contact with, the folded regions of the absorbent layer 206.
The cover layer 302 is joined in any suitable manner, such as by adhesive bonding, heat sealing, ultrasonic bonding, or the like, to the barrier layer 304 around at least the periphery of the barrier layer 104 or a portion thereof. Although the cover layer 302 in
As seen with respect to the embodiment of the absorbent article 300 shown in
The acquisition layer 308 also has regions, extending laterally from the central-most region, that actually contact the inner surface 310 of the absorbent layer 306 throughout the folded regions 309. Other regions of the acquisition layer 308, including additional regions extending laterally toward an outer edge 312 of the acquisition layer 308, extend adjacent to or optionally contact the outer surface 311 of the absorbent layer 306 in the folded regions 309 of the absorbent layer 306.
In its original pre-folded configuration (not shown), the absorbent layer 306 is flat and the layer 306 is then folded or rolled into a substantially C-shaped configuration. While the absorbent layer 306 is in its original flat configuration (not shown), an acquisition layer 308 having a surface area at least as large as the surface area of the absorbent layer 306 is optionally aligned substantially parallel over the layer 306. The absorbent layer 306 is then rolled or folded into a substantially C-shaped configuration, such that the absorbent layer has a central opening 307 and folded regions 309 oriented towards cover layer 302. Thus, the substantially C-shaped configuration of the absorbent layer 306 further defines a central opening 307 between the folded regions 309. More specifically, a central opening 307 is generally defined by a portion of the inner surface 310 of the absorbent layer 306 and the inner edges 313 of the folded regions 309 of the absorbent layer 306.
Excess or outwardly extending portions of the acquisition layer 308 near the absorbent layer 306 and along the lengthwise central axis 1 are then rolled or folded over the folded regions 309 of the absorbent layer 306 so as to cover the outer surfaces 311 of the absorbent layer 306 that are oriented towards the cover layer 302. In other words, other regions of the acquisition layer 308 are positioned between the folded regions 309 of the absorbent layer 306 and cover layer 302 in this manner. As a result, the acquisition layer 308 lines both a central region above the absorbent layer 306 and folded regions 309 of the absorbent layer 306 oriented towards the cover layer 302.
With respect to an absorbent layer 306 having an original flat pre-folded configuration (not shown), the absorbent layer 306 has a top surface that will become oriented towards the cover layer 302 and a bottom surface that will become oriented towards the barrier layer 304 when the absorbent layer 306 is interposed between the cover layer 302 and barrier layer 304. The top surface of the absorbent layer 306 will correspond to the inner surface 310, and the bottom surface will correspond to the outer surface 311.
When an acquisition layer 308 that has a surface area greater than the surface area of the absorbent layer 306 is aligned substantially parallel over the top surface of the absorbent layer 306, edge portions 312 of the acquisition layer 308 extend beyond the edges 313 of the absorbent layer 306, The absorbent layer 306 is then rolled or folded into a substantially C-shaped configuration, such that the top bottom surfaces of the flat layer become the inner surface 310 and outer surface 311 of a C-shaped layer 306, respectively. Therefore, when the absorbent layer 306 is rolled or folded into the substantially C-shaped configuration, the acquisition layer 308 covers, is optionally adjacent to, or optionally contacts the inner surface 310 of the absorbent layer 306 along at least the central-most region 1 of the absorbent layer 306. Additionally, other regions of the acquisition layer 308 are extended via the edge regions 312 of the acquisition layer 308 to contact or become adjacent to the outer surface 311 of the absorbent layer 306 in the folded regions 309 of the absorbent layer 306.
It is contemplated that, in other embodiments, the acquisition layer 308 may line only a portion of the inner surface and/or the outer surface of the folded regions 309 of the absorbent layer 306 which are oriented towards the cover layer 302. The folded regions 309 of the absorbent layer 306 which are lined with the acquisition layer 308 provide a holding area in which large amounts of liquid may pool from the central opening 307 and then be absorbed into the absorbent layer 306. A portion of the outer surface 311 of the absorbent layer 306, which is oriented towards and adjacent to the barrier layer 304, remains un-lined by the acquisition layer 308. When the absorbent article 300 is fully assembled, the portion of the outer surface 311 of the absorbent layer 306 which is oriented towards or adjacent to the barrier layer 304 optionally contacts the barrier layer 304 directly. In this configuration, the acquisition layer 308 is fully utilized and there is less wasted acquisition layer material.
With reference to
Liquid which penetrates the cover layer 602 and into the central opening 607 pools within the central region of the acquisition layer 608 to be absorbed by the absorbent layer 606. As further seen in
It is expected that an absorbent article embodying features of the invention will exhibit improved performance in terms of absorbency rate. It is believed that the absorbency rate, measured in seconds, will be improved significantly because of the openness of the central-most region of the absorbent core, which provides a larger surface area or reservoir for the collection and absorption of fluid.
It is also expected that an absorbent article embodying features of the invention will exhibit improved utilization. It is believed that the capacity of fluid that the absorbent article can hold before leakage (measured using a mannequin test, for example) will approach the total capacity of the absorbent article (measured using an immersion test, for example). In other words, it is believed that a greater percentage of the absorbent article will be utilized before the article reaches its total capacity and before the article leaks. This means that a smaller article could be utilized while maintaining the same performance prior to leakage or that an article of a given size will exhibit improved performance prior to leakage.
In one actual example, total absorbent capacity testing and mannequin testing of an absorbent article with a C-fold absorbent layer as described above in connection with
Accordingly, the Utilization Rate (the ratio of Mannequin Total Capacity to Immersion Total Capacity) is improved. The Utilization rate of exemplary embodiments of the invention is preferably greater than about 85%, more preferably greater than about 90%, and most preferably greater than about 95%.
Although the present invention has been particularly described in conjunction with specific embodiments, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. It is therefore contemplated that the appended claims will embrace any such alternatives, modifications, and variations as falling within the true scope and spirit of the present invention.
