Patent Application
20080077113
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 exemplary features of embodiments 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 a further embodiment of the present invention, a method for producing an absorbent article 100, 200, 400 having refastenable tabs is provided. The method includes the step of providing an absorbent article chassis 101, 201, 301. A step is also provided for connecting a pair of elastic portions 130, 230, 330, 430 to a front 120, 220, 420 or rear 122, 222, 422 section of an absorbent article chassis 101, 201, 301 to form a first connection 128, 228, 328, 428. Non-elastic portions 132, 232, 332, 432 are connected to each elastic portion to form a second connection 129, 229, 329, 429 that is at least as long as the first connection. A fastener portion 134, 234, 334, 434 is attached to each non-elastic portion to complete the refastenable tabs on the absorbent article.
Referring now to the drawing, in which like reference numbers refer to like elements throughout the various figures that comprise the drawing,
The absorbent article 100 has a chassis 101 that typically includes an absorbent core 138 interposed between a barrier layer and a cover layer. When the absorbent article 100 is in place, the cover layer is arranged to face toward the body of the user (i.e. against the skin of the wearer) and the barrier layer is arranged facing away from the wearer. The cover layer is superimposed over the barrier layer, with the absorbent core 138 interposed in between. Although the cover layer and barrier layer are substantially rectangular in the depicted embodiment, the cover layer and/or barrier layer can be any suitable shape and dimension for a design of an absorbent article 100. The cover layer is joined to the barrier layer in any suitable manner such as by adhesive bonding, heat sealing, ultrasonic bonding, stitching or the like around at least the periphery of the absorbent core.
In order to enable liquid to quickly and efficiently pass through the cover layer and into the absorbent core 138 for trapping therein, the cover layer is preferably liquid permeable. 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 such as urine into the outer regions of the absorbent article, leading to leakage. If desired, the cover layer may be formed of a liquid impermeable material having plural apertures or pores extending therethrough so as to make the material liquid permeable.
As seen with respect to the embodiment of the absorbent article 100 shown in
The absorbent core 138 may be of any shape and 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. It 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 is sandwiched between two plies of tissue, is aligned on top of the barrier layer and adhered with construction adhesive. The tissue may typically have a basis weight of about 17 gsm. Suitable tissues are available from Cellu Tissue Corporation, East Hartford, Conn. The absorbent core 138 is typically centered along the transverse direction of the absorbent article 100. In some embodiments of the invention, the front section 120 of the absorbent article 100 has a greater absorbent capacity than the rear section 122, for example by providing a greater basis weight of a superabsorbent material in the front vs. the rear section of the absorbent core 138.
As further seen in
Other materials for forming the barrier layer may include polyethylene films, polypropylene films, co-extruded films (polyethylene and ethylene vinyl acetate), co-polymer films (polyethylene/polypropylene), and polylaminates (polypropylene nonwoven and polyethylene film). Still another example is a film made of a “breathable” microporous polyethylene. Suitable breathable films are available from Tredegar Film Products, Richmond, Va. This material allows water vapor to pass through it over time, while being impervious to liquid water. The water vapor transmission rate may range from 200-2000 grams per square meter per 24-hour period.
With further reference to
The non-elastic portion 132 has a top edge 131 and a bottom edge 133 that are asymmetrical to each other with respect to a horizontal axis. In a preferred embodiment, the top edge 131 has a portion that is more horizontal than the bottom edge 133. It is contemplated that in this configuration, the non-elastic portion provides a better fit at the waist since tensile force is concentrated around the top edge 131 of the non-elastic portion when it is secured around the waist. The bottom edge 133 experiences lesser tensile force when the tab is secured, and provides a better fit and comfort area around the leg. In addition to the force gradient between the top edge 131 and bottom edge 133, force is also distributed along the first connection 128 and second connection 129. The non-elastic portion 132 may have at least one edge that is curved for comfort and fit which may contribute to additional coverage of the buttocks.
In other embodiments, the top edge 131 and bottom edge 133 each has a straight portion that is angled with respect to the horizontal axis. The angle of the straight portion on the top edge is different from the angle of the bottom edge. In general, the non-elastic portion 132 may be of any shape or dimension, but the top edge and bottom edge are asymmetrical when folded with respect to a horizontal axis. Thus, the non-elastic portion has at least one pair of edges that are non-parallel.
Each tab may optionally be formed from a substantially non-elastic material. The tabs may include a portion that is rendered elastic. For instance, an elastic portion can be provided by elasticizing an otherwise non-elastic portion of the tabs. This is optionally accomplished by introducing elastic strands or filaments into or adjacent the non-elastic material.
The non-elastic portion 132 may be formed from a single layer of non-woven material, and may exhibit substantially no elastic/stretch properties (i.e. inelastic). Further, non-elastic portion 132 may be formed of a different material than the absorbent article 100 chassis, thereby desirably allowing the use of less expensive, more breathable, and lower stiffness materials for non-elastic portion components than the chassis. The non-elastic portion 132 is optionally formed from a laminated sheet of a non-woven material and film (with the non-woven side positioned as the outermost layer). One particularly suitable material is a spunbond-meltblow-spunbond (SMS) web having a basis weight of about 5 to 60 gms per square meter (gsm), available from AVGOL Nonwoven Industries LTD., Holon, Israel. The spunbond layer is optionally made of polypropylene fibers. Such composites provide the dual advantages of liquid barrier properties of film along with a soft, warm outer fabric texture.
The non-elastic portion 132 can also be made of other suitable cloth-like materials, e.g., spun-bond or thermal-bond non-woven web made of either polypropylene, polyethylene, polyester, bi-component fibers (polyethylene/polypropylene or polyethylene/polyester), or any combinations of these fibers. Various multiple layer configurations or fiber denier variations may be used. Another example includes hydro-entangled non-woven webs, which may contain some cotton and/or rayon fibers blended in with thermal-plastic fibers. Cellulose fibers can also be blended in at small percentages to reduce cost. Still, other materials for forming the non-elastic portion 132 may include polypropylene films, co-extruded films (polyethylene and ethylene vinyl acetate), co-polymer films (polyethylene/polypropylene), and polylaminates (polypropylene nonwoven and polyethylene film). Yet another example is a film made of a “breathable” microporous polyethylene. Exemplary breathable films are available from Tredegar Film Products, Richmond, Va. This material allows water vapor to pass through it over time, while being impervious to liquid water. The water vapor transmission rate may range from 200-2000 grams per square meter per 24-hour period.
The non-elastic portion 132 is optionally selected from a variety of textile-like films and fabrics. Suitable fabrics include non-woven materials that are impervious to liquid, soft and pliable. Exemplary non-woven materials include spun-bonded polypropylene, spunbonded polyethylene, and thermally bonded webs of staple fibers, preferably sheath/core bi-component fibers having a core of polyester or polypropylene and a sheath of polyethylene.
As depicted in
As further seen in the exemplary embodiment shown in
An embodiment in which the second connection 129 is at least as long as the first connection 128 also allows full utilization of the elastic material that forms the elastic portion 130 between the non-elastic portion 132 and chassis 101. In other words, it is believed that, to the extent one connection is longer or otherwise larger than the other, the geometric portion of the elastic material that corresponds to that difference in connection size is not fully utilized when the tab is pulled or otherwise placed in tension. Although the second connection 129 has been particularly illustrated and described as having a length which is at least as long as the first connection 128, in other embodiments, the first connection 128 may have a length at least as long as the second connection 129.
The elastic portion 130 is preferably stretchable in at least two directions and has a first shape that is substantially rectangular in an unstretched configuration, and a second shape in a stretched configuration. By having an elastic portion 130 that has substantially straight edges, high manufacturing costs are avoided and less elastic material is wasted. It is also contemplated that an elastic portion 130 with at least a pair of edges that have equal lengths and are parallel with respect to each other have a more even spread of force per unit area as the elastic portion 130 is stretched in at least one direction.
As mentioned previously, this feature of this embodiment prevents de-coupling of the non-elastic portion 132 from the elastic portion 130 and decreases the force applied per unit area on the second connection 129 as the elastic portion 130 is stretched. Other benefits of this particular embodiment include distributing force more evenly along the second and first connection which reduces distortion of the tabs when stretched and allows full utilization of the elastic portion 130 between the non-elastic portion 132 and chassis 101. In
The elastic portion 130 may be formed from a fluted elastic or stretch non-woven laminate material obtained, for example, from Tredegar Film Products of Richmond, Va. The elastic portion 130 may include a high-stretch laminate comprising an elastic middle layer sandwiched in between two cloth-like materials. Other stretchable or elastic materials may be used such as elastomeric composites of non-woven(s) and elastic membranes or a single layer of elastic material. A suitable elastomeric composite can comprise an inner layer of pre-stretched extruded elastic film sandwiched between and attached to a pair of non-woven webs. The non-woven webs may consist of spun-bond web, thermal-bond web, or a combination of the two. Optionally, the elastic film is made of synthetic rubber and the non-woven made of spun-bond polypropylene. Other elastic and non-elastic materials may be used as well, depending on design considerations.
In some embodiments of the invention, the elastic portion 130 comprises an elastic material applied in a stretched configuration to a non-elastic substrate, which may for example be a polyolefin or other material used to form a barrier layer for the absorbent article 100. Exemplary elastic materials include elastic films, foams, and nonwoven materials, suitable examples and methods of application of which are known in the art. Examples include Fabriflex® stretch nonwoven film laminate, available from Tredegar Corporation of Richmond, Va., or polyurethane foam laminate, available from General Foam Corporation of Paramus, N.J. The elastic portion 130 which is coupled to the chassis 101 of the absorbent absorbent article 100 may comprise any of a number of elastic materials known in the art, with typical exemplary materials being high-stretch laminates having an elastic middle layer sandwiched between two cloth-like outer layers, such as Fabriflex® film laminate.
A landing zone 126 suitable for engagement with the fastener portion 134 is located on the front section 120 of the absorbent article chassis 101. The area in which the fastener portions 134 and landing zone 126 contact each other will be referred to herein as “engageable portions” of these features. Typically the fastener portion 134 will be of a smaller size than landing zone 126, and hence essentially the entirety of fastener portion 134 will be engageable, while only that portion of landing zone 126 that contacts fastener portion 134 is engaged. However, other configurations are contemplated as well.
The landing zone 126 is preferably located on a surface of the absorbent article chassis 101 opposite that bearing the elastic portion 130, non-elastic portion, and fastener portion 134, so that fastener portion 134 and landing zone 126 may engage each other when the absorbent article 100 is worn by a user. The landing zone 126 is typically of a rectangular shape, but any shape may be used. There may be a single landing zone configured to receive both fasteners portions 134, or separate landing zones may be provided for each fastener portion. Although this embodiment of the invention in
Although not shown in
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.
