US20090094943A1

US20090094943A1 - Absorbent article package with enhanced grip

Info

Publication number: US20090094943A1
Application number: US11/973,828
Authority: US
Inventors: Laura Lynn Heilman; Jill Marlene Orr
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 2007-10-10
Filing date: 2007-10-10
Publication date: 2009-04-16
Also published as: CA2702214A1; WO2009049108A1; EP2217511A1; MX2010003899A

Abstract

A package having an absorbent article and outer package having a web package material, with grip areas. The grip areas enhance gripping, handling, carrying, and stacking of the package. The grip areas include a strainable network having at least two visually distinct regions of the same material composition. The first region undergoes a molecular-level deformation and the second region initially undergoes a substantially geometric deformation when the web package material is subjected to an applied elongation in a direction substantially parallel to the axis of elongation, and wherein the first region and the second region are positioned on one or more grip areas of the outer package, wherein only a portion of the outer package has first and second regions.

Description

FIELD OF THE INVENTION

The present invention relates to a package with absorbent articles and an outer package having a web package material comprising grip areas, which enhance gripping, handling, carrying and stacking of the package. The grip areas exhibit poke through resistance and an elastic-like behavior in response to an applied elongation along at least one axis.

BACKGROUND OF THE INVENTION

Absorbent articles such as paper towels, toilet tissues, facial tissues, sanitary napkins, pantiliners, disposable diapers, incontinent briefs, and bandages, etc. are designed to absorb and retain liquid and/or absorb discharges from the human body to prevent soiling on the body and/or on clothing. Because these types of products are typically consumed rather quickly by consumers, many absorbent articles are packaged and sold in relatively large quantities. By buying in bulk, consumers may not need to return to the store as often and may be able to pay a reduced price per unit. This is because the manufacturers may be able to incur shipping and handling savings and produce the larger packages more efficiently.
Moreover, these packages may be slippery, large, bulky and often have an awkward shape. Therefore, they may be more difficult for consumers to handle and carry. Sometimes consumers may even accidentally puncture the package with their fingers while attempting to grip and carry it. Also, it may be more difficult for retailers to stack these packages in the store for display. As such, a need currently exists for an improved packaging for absorbent articles. In particular, a need exists for a package for absorbent articles with enhanced gripping that is easier for consumers to carry and handle and for retailers to stack and display in the store.
The present invention therefore, provides a package with absorbent articles and an outer package with a web package material, wherein the web package material comprises grip areas. These regions enhance gripping, carrying, and stacking of the package and reduce puncturing of the web package material by the consumer.

SUMMARY OF THE INVENTION

In an embodiment the invention relates to a package comprising: (a) one or more absorbent articles; (b) an outer package for the absorbent articles, comprising a web package material comprising at least two distinct regions comprising a first region and a second region being comprised of the same material composition, the first region undergoing a substantially molecular-level deformation and the second region initially undergoing a substantially geometric deformation when the web package material is subjected to an applied elongation along at least one axis; and wherein the first region and the second region are positioned on one or more grip areas of the outer package, wherein only a portion of the outer package comprises first and second regions.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing out and distinctly claiming the present invention, it is believed that the present invention will be better understood from the following description in conjunction with the accompanying drawings, in which like reference numerals identify like elements and wherein:

FIG. 1 is a plan view illustration of an embodiment of a web package material of the present invention;

FIG. 2 is an exemplary graph of the force-elongation curve of the resistive force versus percent elongation behavior of a web package material of the present invention, such as shown in FIG. 1, and a base web package material, i.e., which does not include first and second regions, of similar or the same material composition;

FIG. 3 is a plan view illustration of the web package material of FIG. 1 in a tensioned condition corresponding to stage I on the force-elongation curve depicted in FIG. 2;

FIG. 4 is a perspective view of the package of the present invention showing grip regions;

FIG. 5 is a perspective view of an embodiment of an apparatus used to form web package materials of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

As used herein, the term “absorbent article” refers to tissue products, sanitary tissue or tissue products, devices which absorb and contain body exudates, and, more specifically, refers to devices which are placed against or in proximity to the body of the wearer to absorb and contain the various exudates discharged from the body. The term “absorbent article” is intended to include diapers, catamenial pads, sanitary napkins, pantiliners, incontinent briefs, bandages, wipes, tissue products, and the like. The term “disposable” is used herein to describe absorbent articles which are not intended to be laundered or otherwise restored or reused as an absorbent article (i.e., they are intended to be discarded after a single use, and, in an embodiment, to be recycled, composted or otherwise disposed of in an environmentally compatible manner).
“Sanitary tissue product” or “tissue product” as used herein means a wiping implement for post-urinary and/or post-bowel movement cleaning (toilet tissue or wipe products), for otorhinolaryngological discharges (facial tissue products) and/or multi-functional absorbent and cleaning uses (absorbent towels such as paper towel products, table napkins and/or wipe products). The sanitary tissue products of the present invention may comprise one or more fibrous structures and/or finished fibrous structures, traditionally, but not necessarily, comprising cellulose fibers. In one embodiment, the tissue products of the present invention include tissue-towel paper products.
A “tissue-towel paper product” refers to products comprising paper tissue or paper towel technology in general, including, but not limited to, conventional felt-pressed or conventional wet-pressed tissue paper, pattern densified tissue paper, starch substrates, and high bulk, uncompacted tissue paper. Non-limiting examples of tissue-towel paper products include toweling, facial tissue, bath tissue, table napkins, and the like.
As used herein, the term “elastic-like” describes the behavior of web package materials which when subjected to an applied elongation, the web package materials extend in the direction of applied elongation and when the applied elongation is released the web package materials return, to a substantial degree, to their untensioned condition.
As used herein the term “web package material” refers to a sheet-like material, including a film material, etc., useful for packaging that may be a composite or laminate of two or more sheet-like materials and the like.
The term “fibrous structure”, as used herein, means an arrangement of fibers produced in any papermaking machine known in the art to create a ply of paper. “Fiber” means an elongate particulate having an apparent length greatly exceeding its apparent width. More specifically, and as used herein, fiber refers to such fibers suitable for a papermaking process.
“Basis Weight”, as used herein, is the weight per unit area of a sample reported in lbs/3000 ft²or g/m².
“Machine Direction” or “MD”, as used herein, means the direction parallel to the flow of the fibrous structure through the papermaking machine and/or product manufacturing equipment.
“Cross Machine Direction” or “CD”, as used herein, means the direction perpendicular to the machine direction in the same plane of the fibrous structure and/or fibrous structure product comprising the fibrous structure.

Absorbent Articles

The package herein comprises a one or more absorbent articles. In one embodiment the absorbent articles herein comprise tissue products. The tissue products may be in any suitable form, such as in a roll, in individual sheets, in connected, but perforated sheets, in a folded format or even unfolded.
In one example, tissue products comprise a plurality of single- and/or multi-ply sanitary tissue products. The sanitary tissue products may be dry and/or wet. The sanitary tissue products may come in a variety of roll sizes and may be packaged in different numbers of rolls, such as four, six, nine, twenty-four, thirty-six and the like. The packages may be displayed on a shelf at a point of sale, such as within a retail store, in such as way that the different sanitary tissue products or packages are visible to a consumer during the consumer's purchasing decision process.
The sanitary tissue products may comprise single ply or more multi-ply sanitary tissue products. The package may comprise a mixture of single-ply and multi-ply sanitary tissue products.
The absorbent article may comprise any tissue-towel paper product known in the industry. Embodiment of these substrates may be made according U.S. Pat. No.: 4,191,609 issued Mar. 4, 1980 to Trokhan; U.S. Pat. No. 4,300,981 issued to Carstens on Nov. 17, 1981; U.S. Pat. No. 4,191,609 issued to Trokhan on Mar. 4, 1980; U.S. Pat. No. 4,514,345 issued to Johnson et al. on Apr. 30, 1985; U.S. Pat. No. 4,528,239 issued to Trokhan on Jul. 9, 1985; U.S. Pat. No. 4,529,480 issued to Trokhan on Jul. 16, 1985; U.S. Pat. No. 4,637,859 issued to Trokhan on Jan. 20, 1987; U.S. Pat. No. 5,245,025 issued to Trokhan et al. on Sep. 14, 1993; U.S. Pat. No. 5,275,700 issued to Trokhan on Jan. 4, 1994; U.S. Pat. No. 5,328,565 issued to Rasch et al. on Jul. 12, 1994; U.S. Pat. No. 5,334,289 issued to Trokhan et al. on Aug. 2, 1994; U.S. Pat. No. 5,364,504 issued to Smurkowski et al. on Nov. 15, 1995; U.S. Pat. No. 5,527,428 issued to Trokhan et al. on Jun. 18, 1996; U.S. Pat. No. 5,556,509 issued to Trokhan et al. on Sep. 17, 1996; U.S. Pat. No. 5,628,876 issued to Ayers et al. on May 13, 1997; U.S. Pat. No. 5,629,052 issued to Trokhan et al. on May 13, 1997; U.S. Pat. No. 5,637,194 issued to Ampulski et al. on Jun. 10, 1997; U.S. Pat. No. 5,411,636 issued to Hermans et al. on May 2, 1995; EP 677612 published in the name of Wendt et al. on Oct. 18, 1995, and U.S. Patent Application 2004/0192136A1 published in the name of Gusky et al. on Sep. 30, 2004.

Outer Package Comprising Web Package Material

The present invention provides that only specific portions or locations of the outer package comprise web package material with a strainable network comprised of first and second regions. These specific portions are selected so that the grip of the package is enhanced. The grip areas render the package less slippery and facilitate easier carrying by the consumer. Further, since many absorbent article packages are damaged by the consumer or retail store employees during handling, the grip areas also provide enhanced poke through resistance of the package. Grip areas also may reduce slip of the package on the shelf or reduce slip between packages to facilitate stacking of the package for display in the store (e.g. on pallets, floors, or shelves).
In one embodiment the web package material of the invention herein comprises an Energy Ratio (E) of greater than about 1, greater than about 1.1, and/or greater than about 1.18, and a Deflection Ratio (D) of greater than about 1, and/or greater than about 1.2. The energy values represent the energy in inches/lbs. to induce failure of the web package material according to the following formula:
$E (Energy Ratio) = \frac{Energy (at failure in inches / lbs .) of X^{1}}{Energy (at failure in inches / lbs .) of Y^{2}}$
The Deflection Ratio represents the peak deflection in inches without inducing failure of the web package material according to the following formula:
$D (Deflection Ratio) = \frac{Peak Delfection (inches) of X}{Peak Deflection (inches) of Y}$
For example, the D and E values for samples of the grip area of the web package material of the present invention are as follows:
Mean Energy at Failure

Film Mean Deflection of 12 of 12 Samples

Sample Samples at Peak (inches) (inches/lbs.)

X 0.3658 0.5157

Y 0.2904 0.4459

These D and E measurements are generated according to ASTM F 1306.
Moreover, in one embodiment, the grip areas of the web package material herein have a Coefficient of Friction Ratio (COF Ratio) of greater than about 1, greater than about 1.2, and/or greater than about 1.4. The COF represents the resistance of the movement of the sample against the selected substrate.
The COF Ratio is calculated as follows:
¹Web package material having 1.25 mils thickness comprising a conventional polyethylene film with a mixture of LDPE, MDPE, HDPE, from Southern Film Extruder, with grip areas having first and second regions and a depth of engagement of 0.025 inches according to the present invention.
²Web package material X without grip areas having first and second regions.
$C O F Ratio = \frac{C O F (dynamic) of A^{3}}{C O F (dynamic) of B^{4}}$
³Web package material having 1.25 mils thickness comprising a conventional polyethelyne film with a mixture of LDPE, MDPE, HDPE, from Southern Film Extruder, with first and second regions and a depth of engagement of 0.025 inches of present invention and in either the MD or CD direction.
⁴Web package material A without grip areas having first and second regions.
For example, COF values for samples of the grip area of the web package material of the present invention are as follows:


	Film Sample	Mean COF of 5 Samples

	A (MD)	0.434
	A (CD)	0.536
	B	0.372

For example, the COF values are generated according to ASTM D 1894 as indicated in the Test Methods section herein.
The present invention pertains, in an embodiment, to a web package material which exhibits an elastic-like behavior in response to an applied and subsequently released elongation without the addition of traditional elastic materials such as natural or synthetic rubber.
Another elastic-like behavior that the web package material of the present invention may exhibit is an initial elongation and partial recovery which results in the web package material not returning to its untensioned length, i.e., the web package material has undergone a degree of permanent set or deformation and has a new longer untensioned length. The web package material may exhibit an elastic-like behavior in response to subsequent elongations of the web package material beyond the new longer untensioned length.
Another elastic-like behavior that may be exhibited is an elongation and recovery with a definite and sudden increase in the force resisting elongation where this definite and sudden increase in resistive force restricts further elongation against relatively small elongation forces. The definite and sudden increase in the force resisting elongation is referred to as a “force wall”. As used herein, the term “force wall” refers to the behavior of the resistive force of a web package material during elongation wherein at some point in the elongation, distinct from the untensioned or starting point, the force resisting the applied elongation suddenly increases. After reaching the force wall, additional elongation of the web package material is only accomplished
³Web package material having 1.25 mils thickness comprising a conventional polyethylene film with a mixture of LDPE, MDPE, HDPE, from Southern Film Extruder, with first and second regions and a depth of engagement of 0.025 inches of present invention and in either the MD or CD direction.
⁴Web package material A without grip areas having first and second regions. via an increase in the elongation force to overcome the higher resistive force of the web package material.
The web package material of the present invention comprises a strainable network having at least two visually distinct and dissimilar regions comprised of the same material composition. The first region is oriented substantially parallel to an axis of elongation such that it will undergo a molecular-level deformation in response to an applied axial elongation in a direction substantially parallel to the axis before a substantial portion of the second region undergoes any substantial molecular-level deformation. As used herein, the term “substantially parallel” refers to an orientation between two axes whereby the subtended angle formed by the two axes or an extension of the two axes is less than 45 degrees. In the case of a curvilinear element it may be more convenient to use a linear axis which represents an average of the curvilinear element. The second regions initially undergo a substantially geometric deformation in response to an applied elongation in a direction substantially parallel to the axis.
In another embodiment, the second region is comprised of a plurality of raised rib-like elements. In one embodiment the rib-like elements have a major axis and a minor axis. In an embodiment, the major axis is at least as long as the minor axis. The major axes of the rib-like elements are, in an embodiment, oriented substantially perpendicular to the axis of applied elongation. The major axis and the minor axis of the rib-like elements may each be linear, curvilinear or a combination of linear and curvilinear. As used herein, the term “substantially perpendicular” refers to an orientation between two axes whereby the subtended angle formed by the two axes or an extension of the two axes is greater than 45 degrees. In the case of a curvilinear element it may be more convenient to use a linear axis which represents an average of the curvilinear element.
The rib-like elements allow the second region to undergo a substantially “geometric deformation” which results in significantly less resistive forces to an applied elongation than that exhibited by the “molecular-level deformation” of the first region. As used herein, the term “molecular-level deformation” refers to deformation which occurs on a molecular level and is not discernible to the normal naked eye. That is, even though one may be able to discern the effect of molecular-level deformation, e.g., elongation of the web package material, one is not able to discern the deformation which allows or causes it to happen. This is in contrast to the term “geometric deformation”. As used herein the term “geometric deformation” refers to deformations of the web package material which are discernible to the normal naked eye when the web package material or packaging embodying the web package material are subjected to an applied elongation. Types of geometric deformation include, but are not limited to bending, unfolding, and rotating.
Yet another elastic-like behavior that the web package material of the present invention may exhibit is an elongation and recovery with two or more significantly different force walls. This type of elastic-like behavior would be experienced if for example, after reaching a first force wall, sufficient elongation force was applied to overcome the first force wall and continue to elongate the web until a second force wall was encountered.
When the web package material of the present invention has multiple or staged force walls, rib-like elements in one or more of the second regions reach their limit of geometric deformation and become essentially coplanar with the material in the first region, thereby causing the web package material to exhibit a first force wall. Further elongation of the web package material molecularly deforms the rib-like elements which have reached their limit of geometric deformation, and simultaneously geometrically deforms the rib-like elements in the remaining second regions until they reach their limit of geometric deformation thereby causing the web package material to exhibit a second force wall.
In another embodiment, the web package material of the present invention exhibits at least two significantly different stages of resistive force to an applied elongation along at least Cone axis when subjected to an applied elongation in a direction substantially parallel to the axis. The web package material includes a strainable network having at least two visually distinct regions. One of the regions is configured such that it will exhibit resistive forces in response to an applied axial elongation in a direction substantially parallel to the axis before a substantial portion of the other region develops any significant resistive force to the applied elongation. At least one of the regions has a surface-pathlength which is greater than that of the other region as measured substantially parallel to the axis while the material is in an untensioned condition. The region exhibiting the longer surface-pathlength includes one or more rib-like elements which extend beyond the plane of the other region. The web package material exhibits first resistive forces to the applied elongation until the elongation of the web package material is sufficient to cause a substantial portion of the region having the longer surface-pathlength to enter the plane of applied elongation, whereupon the web package material exhibits second resistive forces to further elongation. The total resistive force to elongation is higher than the first resistive force to elongation provided by the first region.
In an embodiment, the first region has a first surface-pathlength, L1, as measured substantially parallel to the axis of elongation while the web package material is in an untensioned condition. The second region has a second surface-pathlength, L2, as measured substantially parallel to the axis of elongation while the web is in an untensioned condition. The first surface-pathlength, L1, is less than the second surface-pathlength, L2. The first region, in an embodiment, has an elastic modulus, E1, and a cross-sectional area, A1. The first region produces by itself a resistive force, P1, due to molecular-level deformation in response to an applied axial elongation, D. The second region, in an embodiment, has an elastic modulus, E2, and a cross-sectional area, A2. The second region produces a resistive force, P2, due to geometric deformation in response to the applied axial elongation, D. The resistive force, P1, is significantly greater than the resistive force, P2, so long as (L1+D) is less than L2.
In an embodiment, when (L1+D) is less than L2 the first region provides an initial resistive force, P1, in response to the applied axial elongation, D, substantially satisfying the equation:
$P 1 = \frac{A 1 \times E 1 \times D}{L 1}$
When (L1+D) is greater than L2 the first and second regions provide a total resistive force, PT, to the applied axial elongation, D, satisfying the equation:
$PT = \frac{(A 1 \times E 1 \times D)}{L 1} + \frac{(A 2 \times E 2 \times [L 1 + D - L 2])}{L 2}$
In another embodiment, the web package material exhibits a Poisson lateral contraction effect of from about 0.44 to about 0.9 and/or about 0.48 to about 0.8 at 20% elongation as measured perpendicular to the axis of elongation and exhibits a Poisson lateral contraction effect from about 0.42 to about 0.9 and/or about 0.44 to about 0.8 at 60% elongation as measured perpendicular to the axis of elongation. As used herein, the term “Poisson lateral contraction effect” describes the lateral contraction behavior of a material which is being subjected to an applied elongation. Web package material herein exhibits a modified Poisson lateral contraction effect that is less than that of an otherwise identical base web of similar material composition, i.e., a web having no first and second regions. In another embodiment the web package material (e.g. having the first and second regions) is at least about 0.25 less than the Poisson lateral contraction effect of the identical base web of similar material composition at 20% elongation, and is at least about 0.16 less than the Poisson lateral contraction effect of the identical base web of similar material composition at 60% elongation.
In an embodiment, the surface-pathlength of the second region is at least about 15% greater than that of the first region as measured parallel to the axis of elongation while the web package material is in an untensioned condition. In another embodiment, the surface-pathlength of the second region is at least about 30% greater than that of the first region as measured parallel to the axis of elongation while the web is in an untensioned condition.
Web package materials of the present invention may be comprised of the materials disclosed in U.S. Patent Application 2004/0265534, Curro, et al., published Dec. 30, 2004, and/or polyolefins such as polyethylenes, including linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE) ultra low density polyethylene (LLDPE), high density polyethylene (HDPE), or polypropylene and blends thereof with the above and other materials.
Examples of other suitable polymeric materials which may also be used include, but are not limited to, polyester, polyurethanes, compostable or biodegradable polymers, heat shrink polymers, thermoplastic elastomers, metallocene catalyst-based polymers (e.g., INSITE® available from Dow Chemical Company and Exxact® available from Exxon), and breathable polymers. The web package material may also be comprised of a synthetic woven, synthetic knit, nonwoven, apertured film, macroscopically expanded three-dimensional formed film, absorbent or fibrous absorbent material, foam, filled composition, or laminates and/or combinations thereof. The nonwovens may be made by but not limited to any of the following methods: spunlace, spunbond, meltblown, carded and/or air-through or calendar bonded, with a spunlace material with loosely bound fibers being one embodiment.
While the present invention has been described as providing a web package material from a single layer of base film, the present invention may be practiced equally well with other materials. Examples of other base materials from which the web package material of the present invention can be made include two-dimensional apertured films and macroscopically expanded, three-dimensional, apertured formed films. Examples of macroscopically expanded, three-dimensional, apertured formed films are described in U.S. Pat. No. 3,929,135, issued to Thompson on Dec. 30, 1975; U.S. Pat. No. 4,324,246 issued to Mullane, et al. on Apr. 13, 1982; U.S. Pat. No. 4,342,314 issued to Radel, et al. on Aug. 3, 1982; U.S. Pat. No. 4,463,045 issued to Ahr, et al. on Jul. 31, 1984; and U.S. Pat. No. 5,006,394 issued to Baird on Apr. 9, 1991.
Web package materials of the present invention may include laminates of the above mentioned materials. Laminates may be combined by any number of bonding methods known to those skilled in the art. Such bonding methods include but are not limited to thermal bonding, adhesive bonding (using any of a number of adhesives including but not limited to spray adhesives, hot melt adhesives, latex based adhesives and the like), sonic bonding and extrusion laminating whereby a polymeric film is cast directly onto a substrate, and while still in a partially molten state, bonds to one side of the substrate, or by depositing meltblown fibers nonwoven directly onto a substrate.
FIG. 1. shows an embodiment of a web package material 52 of the present invention. The web package material 52 is shown in FIG. 1 in its substantially untensioned condition. The web package material 52 has two centerlines, a longitudinal centerline, which is also referred to hereinafter as an axis, line, or direction “L” and a transverse or lateral centerline, which is also referred to hereinafter as an axis, line, or direction “T3”. The transverse centerline “T” is generally perpendicular to the longitudinal centerline “L”.
Web package material 52 includes a “strainable network” of distinct regions. As used herein, the term “strainable network” refers to an interconnected and interrelated group of regions which are able to be extended to some useful degree in a predetermined direction providing the web package material with an elastic-like behavior in response to an applied and subsequently released elongation. The strainable network includes a plurality of first regions 60 and a plurality of second regions 66. Web package material 52 also includes transitional regions 65 which are located at the interface between the first regions 60 and the second regions 66. The transitional regions 65 will exhibit complex combinations of the behavior of both the first region and the second region. It is recognized that every embodiment of the present invention will have transitional regions, however, the present invention is largely defined by the behavior of the web package material in distinctive regions (e.g., first regions 60 and second regions 66). Therefore, the ensuing description of the present invention will be concerned with the behavior of the web package material in the first regions 60 and the second regions 66 only since it is not significantly dependent upon the complex behavior of the web package material in the transitional regions 65.
Web package material 52 has a first surface, (facing the viewer in FIG. 1), and an opposing second surface. A portion of the first regions 60, indicated generally as 61, are substantially linear and extend in a first direction. The remaining first regions 60, indicated generally as 62, are substantially linear and extend in a second direction which is substantially perpendicular to the first direction. While in one embodiment the first direction is perpendicular to the second direction, other angular relationships between the first direction and the second direction may be suitable so long as the first regions 61 and 62 intersect one another. In one embodiment, the angles between the first and second directions ranges from about 45° to about 135°, and may be about 90°. The intersection of the portions and remaining first regions 61 and 62 forms a boundary, indicated by phantom line 63 in FIG. 1, which completely surrounds the second regions 66.
In one embodiment, the width 68 of the first regions 60 is from about 0.01 inches to about 0.5 inches, and/or from about 0.03 inches to about 0.25 inches. However, other width dimensions for the first regions 60 may be suitable. Because the portions and remaining first regions 61 and 62 are perpendicular to one another and equally spaced apart, the second regions have a square shape. However, other shapes for the second region 66 are suitable and may be achieved by changing the spacing between the first regions and/or the alignment of the first regions 61 and 62 with respect to one another. The second regions 66 have a first axis 70 and a second axis 71. The first axis 70 is substantially parallel to the longitudinal axis of the web package material 52, while the second axis 71 is substantially parallel to the transverse axis of the web package material 52. The first regions 60 have an elastic modulus E1 and a cross-sectional area A1. The second regions 66 have an elastic modulus E2 and a cross-sectional area A2.
In the illustrated embodiment, the web package material 52 has been “formed” such that the web package material 52 exhibits a resistive force along an axis, which in the case of the illustrated embodiment is substantially parallel to the transverse axis of the web, when subjected to an applied axial elongation in a direction substantially parallel to the transverse axis. As used herein, the term “formed” refers to the creation of a desired structure or geometry upon a web package material that will substantially retain the desired structure or geometry when it is not subjected to any eternally applied elongations or forces. A web package material of the present invention may be comprised of a plurality of first regions and a plurality of second regions, wherein the first regions are visually distinct from the second regions. As used herein, the term “visually distinct” refers to features of the web package material which are readily discernible to the normal naked eye when the web package material or a package embodying the web package material are subjected to normal use. As used herein the term “surface-pathlength” refers to a measurement along the topographic surface of the region in question in a direction substantially parallel to an axis. The method for determining the surface-pathlength of the respective regions can be found in the Test Methods section set forth herein.
In the embodiment shown in FIG. 1 the first regions 60 are substantially planar. That is, the material within the first regions 60 is in substantially the same condition before and after the formation step undergone by web package material 52. The second regions 66 include a plurality of raised rib-like elements 74.
The rib-like elements 74 may be embossed, debossed or a combination thereof. The rib-like elements 74 have a first or major axis 76 which is substantially parallel to the longitudinal axis of the web package material 52 and a second or minor axis 77 which is substantially parallel to the transverse axis of the web package material 52.
The rib-like elements 74 in the second region 66 may be separated from one another by unformed areas, essentially unembossed or debossed, or simply formed as spacing areas. In one embodiment, the rib-like elements 74 are adjacent one another and are separated by an unformed area of less than 0.10 inches as measured perpendicular to the major axis 76 of the rib-like elements 74, and/or, the rib-like elements 74 are contiguous having no unformed areas between them.
The first regions 60 and the second regions 66 each have a “projected pathlength”. As used herein the term “projected pathlength” refers to the length of a shadow of a region that would be thrown by parallel light. The projected pathlength of the first region 60 and the projected pathlength of the second region 66 are equal to one another.
The first region 60 has a surface-pathlength, L1, less than the surface-pathlength, L2, of the second region 66 as measured topographically in a parallel direction while the web is in an untensioned condition. For example, the surface-pathlength of the second region 66 is at least about 15% greater than that of the first region 60, and/or at least about 30% greater than that of the first region, and/or at least about 70% greater than that of the first region. In one embodiment, the greater the surface-pathlength of the second region, the greater will be the elongation of the web before encountering the force wall.
Web package material 52 exhibits a modified “Poisson lateral contraction effect” substantially less than that of an otherwise identical base web of similar material composition, i.e., a web having no first and second regions. The method for determining the Poisson lateral contraction effect of a material can be found in the Test Methods section herein. The Poisson lateral contraction effect of web package material of the present invention is determined by the amount of the web package material which is occupied by the first and second regions, respectively. As the area of the web package material occupied by the first region increases the Poisson lateral contraction effect also increases. Conversely, as the area of the web package material occupied by the second region increases the Poisson lateral contraction effect decreases. In an embodiment, the percent area of the web package material occupied by the first region of the grip area, is from about 2% to about 90%, and/or from about 5% to about 50%.
Web package materials of the prior art which have at least one layer of an elastomeric material will generally have a large Poisson lateral contraction effect, i.e., they will “neck down” as they elongate in response to an applied force. Web package materials of the present invention can be designed to moderate if not substantially eliminate the Poisson lateral contraction effect.
For web package material 52, the direction of applied axial elongation, D, indicated by arrows 80 in FIG. 1, is substantially perpendicular to the first axis 76 of the rib-like elements 74. This is due to the fact that the rib-like elements 74 are able to unbend or geometrically deform in a direction substantially perpendicular to their first axis 76 to allow extension in web 52.
In FIG. 2 there is shown an exemplary graph of a resistive force-elongation curve 720 of a web package material generally similar to web package material 52 shown in FIG. 1 along with a curve 710 of a base web package material of similar composition. The method for generating resistive force-elongation curves can be found in the Test Methods section herein. Referring now to the force-elongation curve 720 of the formed web of the present invention, there is an initial substantially linear, lower force versus elongation stage I designated 720 a, a transition zone designated 720 b which indicates the encounter of the force wall, and a substantially linear stage II designated 720 c which displays substantially higher force versus elongation behavior.
As seen in FIG. 2 the formed web exhibits different elongation behavior in the two stages when subjected to an applied elongation in a direction parallel to the transverse axis of the web. The resistive force exerted by the formed web to the applied elongation is significantly less in the stage I region (720 a) versus the stage II region (720 c) of curve 720. Furthermore, the resistive force exerted by the formed web to the applied elongation as depicted in stage I (720 a) of curve 720 is significantly less than the resistive force exerted by the base web as depicted in curve 710 within the limits of elongation of stage I. As the formed web is subjected to further applied elongation and enters stage II (720 c) the resistive force exerted by the formed web increases and approaches the resistive force exerted by the base web. The resistive force to the applied elongation for the stage I region (720 a) of the formed web is provided by the molecular-level and geometric deformation of the first region of the formed web and the geometric deformation of the second region of the formed web. This is in contrast to the resistive force to an applied elongation that is provided by the base web, depicted in curve 710 of FIG. 2, which results from molecular-level deformation of the entire web. Web package materials of the present invention can be designed to yield virtually any resistive force in stage I which is less than that of the base web package material by adjusting the percentage of the web surface which is comprised of the first and second regions, respectively. The force-elongation behavior of stage I can be controlled by adjusting the width, cross-sectional area, and spacing of the first region and the composition of the base web.
Referring now to FIG. 3, as web package material 52 is subjected to an applied axial elongation, D, indicated by arrows 80 in FIG. 3, the first regions 60 having the shorter surface-pathlength, L1, provide most of the initial resistive force, P1, as a result of molecular-level deformation, to the applied elongation which corresponds to stage I. While in stage I, the rib-like elements 74 in the second regions 66 are experiencing geometric deformation, or unbending and offer minimal resistance to the applied elongation. In addition, the shape of the second regions 66 changes as a result of the movement of the reticulated structure formed by the intersecting first regions 61 and 62. Accordingly, as the web package material 52 is subjected to the applied elongation, the first regions 61 and 62 experience geometric deformation or bending, thereby changing the shape of the second regions 66. The second regions are extended or lengthened in a direction parallel to the direction of applied elongation, and collapse or shrink in a direction perpendicular to the direction of applied elongation.
In the transition zone (720 b) between stages I and II, the rib-like elements 74 are becoming aligned with, (i.e., coplanar with), the applied elongation. That is, the second region 66 is exhibiting a change from geometric deformation to molecular-level deformation. This is the onset of the force wall. In stage II, the rib-like elements 74 in the second region 66 are substantially aligned with, (i.e., coplanar with), the axis of applied elongation (i.e. the second region has reached its limit of geometric deformation) and begin to resist further elongation via molecular-level deformation. The second region 66 now contributes, as a result of molecular-level deformation, a second resistive force, P2, to further applied elongation. In stage II, the first regions 61 and 62 have also reached their limit of geometric deformation and resist further elongation mainly via molecular-level deformation. The resistive forces to elongation depicted in stage II by both the molecular-level deformation of the first regions 60 and the molecular-level deformation of the second regions 66 provide a total resistive force, PT, which is greater than the resistive force depicted in stage I which is provided by the molecular-level and geometric deformation of the first regions 60 and the geometric deformation of the second regions 66. Accordingly, the slope of the force-elongation curve in stage II is significantly greater than the slope of the force-elongation curve in stage I.
The maximum elongation occurring while in stage I is referred to as the “available stretch” of the web package material. The available stretch corresponds to the distance over which the second region experiences geometric deformation. The available stretch can be effectively determined by inspection of the force-elongation curve 720 as shown in FIG. 2. The approximate point at which there is an inflection in the transition zone between stage I and stage II is the percent elongation point of “available stretch”. The range of available stretch can be varied from about 10% to 100% or more; this range of elongation is often found to be of interest in disposable absorbent articles, and can be largely controlled by the extent to which the surface-pathlength L2 in the second region exceeds the surface-pathlength L1 in the first region and the composition of the base film. The term available stretch is not intended to imply a limit to the elongation which the web of the present invention may be subjected to as there are applications where elongation beyond the available stretch is desirable.
When the web package material is subjected to an applied elongation, the web package material exhibits an elastic-like behavior as it extends in the direction of applied elongation and returns to its substantially untensioned condition once the applied elongation is removed, unless the web package material is extended beyond the point of yielding. The web package material is able to undergo multiple cycles of applied elongation without losing its ability to substantially recover. Accordingly, the web package material is able to return to its substantially untensioned condition once the applied elongation is removed.
While the web package material may be easily and reversibly extended in the direction of applied axial elongation, in a direction substantially perpendicular to the first axis 76 of the rib-like elements 74, the web package material is not as easily extended in a direction substantially parallel to the first axis 76 of the rib-like elements 74. The formation of the rib-like elements allows the rib-like elements to geometrically deform in a direction substantially perpendicular to the first or major axis 76 of the rib-like elements, while requiring substantially molecular-level deformation to extend in a direction substantially parallel to the first axis of the rib-like elements.
The amount of applied force required to extend the web package material is dependent upon the composition and cross-sectional area of the web package material and the width and spacing of the first regions, with narrower and more widely spaced first regions requiring lower applied extensional forces to achieve the desired elongation for a given composition and cross-sectional area.
The depth and frequency of rib-like elements can also be varied to control the available stretch of a web package material of the present invention. The available stretch is increased if for a given frequency of rib-like elements, the height or degree of formation imparted on the rib-like elements is increased. Similarly, the available stretch is increased if for a given height or degree of formation, the frequency of the rib-like elements is increased.
There are several functional properties that can be controlled through the application of the present invention. The functional properties are the resistive force exerted by the web package material against an applied elongation and the available stretch of the web package material before a force wall is encountered. The resistive force that is exerted by the web package material against an applied elongation is a function of the material (e.g., composition, molecular structure and orientation, etc.) and cross-sectional area and the percent of the projected surface area of the web package material that is occupied by the first region. The higher the percent area coverage of the web package material by the first region, the higher the resistive force that the web will exert against an applied elongation for a given material composition and cross-sectional area. The percent coverage of the web package material by the first region is determined in part if not wholly by the widths of the first regions and the spacing between adjacent first regions.
The available stretch of the web package material is determined by the surface-pathlength of the second region. The surface-pathlength of the second region is determined at least in part by the rib-like element spacing, rib-like element frequency and depth of formation of the rib-like elements as measured perpendicular to the plane of the web package material. In general, the greater the surface-pathlength of the second region the greater the available stretch of the web package material.
FIG. 4 shows an embodiment of a package 100 of the present invention having a plurality of absorbent articles 101, an outer package 103 comprising a web package material 105 shown in its substantially untensioned condition. A portion of the package or a portion of the surface of the package comprises one or more grip areas. In one embodiment the first regions and the second regions of the web package material are located within the grip areas of the package. In one embodiment the first regions and the second regions of the web package material are exclusively located in the grip areas. The web package material comprises one or more grip areas which may comprise a top grip area 102, side grip area(s) 104, bottom grip area 106, and/or grip may be located in the gusseted area of the package, e.g. the “gusseted grip area”. The configuration and location of the first regions and the second regions in the grip areas enhances the handling and carrying of the package by the consumer, enhances stacking of the packaging, and improves poke through resistance of the outer package.
In one embodiment the grip areas may be any shape, or may be in the shape of a hand and/or extend beyond the shape of the hand. In another embodiment the grip area may be in the shape of a bear paw similar to that used with the Charmin brand of toilet paper manufactured by P&G. In one embodiment the grip areas comprise less that about 90%, less than about 80%, and/or less than about 75%, or from about 5% to about 50% and/or from about 10% to about 40%, and/or about 10% to about 30%, of the total outward facing surface area of the outer package. For a package having multiple rolls of toilet tissues, facial tissues or paper towels, the grip area(s) may be located on the package between the rolls of product, be located in the areas on the top or bottom of the package, and/or may be located partially around the circumference of the roll(s) at the side of the package (e.g., see side grip areas 104 of FIG. 4). In one embodiment the outer package may be gusseted, and the grip area may be located on the gusseted area. In one embodiment the grip area may be located across the entire top surface 107 or the entire bottom surface of the outer package.

Method of Making

Methods for forming web package materials of the present invention include, but are not limited to embossing by mating plates or rolls, thermoforming, high pressure hydraulic forming, or casting.
Referring now to FIG. 6, there is shown an apparatus 400 used to form the web package material 52 shown in FIG. 1. Apparatus 400, includes intermeshing plates 401, 402. Plates 401, 402 include a plurality of intermeshing teeth 403, 404, respectively. Plates 401, 402 are brought together under pressure to form the web package material of the present invention.
Plate 402 includes toothed regions 407 and grooved regions 408. Within toothed regions 407 of plate 402 there are a plurality of intermeshing teeth 404. Plate 401 includes intermeshing teeth 403 which mesh with intermeshing teeth 404 of plate 402. When a film is formed between plates 401, 402 the portions of the film which are positioned within grooved regions 408 of plate 402 and teeth 403 on plate 401 remain undeformed. These regions correspond with the first regions 60 of web 52 shown in FIG. 1. The portions of the film positioned between toothed regions 407 of plate 402, (which comprise teeth 404), and teeth 403 of plate 401 are incrementally and plastically formed creating rib-like elements 74 in the second regions 66 of web package material 52, of FIG. 1.
The method of formation can be accomplished in a static mode, where one discrete portion of a base film is deformed at a time. Alternatively, the method of formation can be accomplished using a continuous, dynamic press for intermittently contacting the moving web and forming the base material into a formed web package material of the present invention. These and other suitable methods for forming the web package material of the present invention are more fully described in U.S. Pat. No. 5,518,801 issued to Chappell, et al. on May 21, 1996.

Test Methods

COF

COF values are generated according to ASTM D 1894. Substitute a 3.75″ wide 111.6 g skin mimic (that mimics the properties of skin on a human forearm) made according to the following process, for the metal sled. The path length is 200 mm versus 250 mm, and the rate is 150 mm/min.
For the skin mimic first make a negative imprint of keratinous tissue by applying a material (suitable materials include PLY-O-LIFE™ and ALGIFORM™ casting material, both available from Pink House Studios (St. Albans, Vt.); or other suitable equivalent materials) capable of forming a cast, or mold, onto a human forearm. (To make imprints of other keratinous tissue, a negative imprint similarly may be made of another body part, for example, human skin on other parts of the body, lips, hair, etc.). When set, remove the cast and allow to dry for 3-7 min. Create a positive mold that resembles the body part in both form and texture by placing, for example, silicone or other suitable material in the negative mold. Remove the material from the negative mold to obtain the positive mold, and impress the positive mold into polyurethane or other suitable material to create a second negative mold. Remove the positive mold and allow the second negative mold to cure overnight. Optionally, the positive mold may be pressed into a unitary mold of polyurethane or other suitable material to create multiple negative molds. Alternatively, a negative mold containing the skin-texture can be made into a variety of shapes, for example a square shape of 10×10 cm.
To form the first layer, spray coat the second negative mold with a 1:1 mixture of Skin-Flex SC-89²stretch paint (aliphatic polyurethane gloss paint) and Skin-Flex SC-89 thinner³to create a layer having a thickness of from about 100 μm to about 600 μm, and allow to dry for at least 12 hours.
To form the second layer, pour an amount of a suitable second material having a hardness of from about 45 to about 60 on the Shore OOO scale for the second layer, for example XP-574⁴, sufficient to create a layer having a thickness of from about 0.01 cm to about 1 cm onto the dried first layer. Prior to pouring, de-gas the liquid polymers sufficiently to remove undesirable trapped air bubbles. Allow to cure/dry for about 24 hours.
To form the third layer, pour an amount of a suitable de-gassed material, for example, PC-16⁵, onto the second layer. The amount should be sufficient to create a layer having a thickness of from about 0.1 cm to about 1 cm, onto the dried second layer. Allow to cure/dry for about 24 hours.
Allow the resulting multi-layered substrate to cure for at least an additional 24 hours before gently removing from the second negative mold. The surface of the substrate may be modified by using atmospheric plasma treatments and/or other suitable chemical treatments. The substrates may be used to simulate a number of body parts, for example human wet skin, young skin, aged and/or damaged skin, the forehead, hands, shinbone, and/or cheek area.
¹Other suitable materials include dental materials, liquid rubber, room temperature vulcanized (RTV) rubber, plastic, or equivalents thereof.
²SC-89 Stretch Paint, available from Burman Industries (Van Nuys, Calif.).
²SC-89 Thinner, available from Burman Industries, (Van Nuys, Calif.).

⁴XP-574, BJB Industries (Tustin, Calif.)

⁵PC-16, available from BJB Industries (Tustin, Calif.). Other suitable materials include PC-15, XP-573, TC-410 polyurethane, Part A (aromatic diisocyanate based pre-polymer, plasticizer mixture) and Part B, polyurethane curing agent, for example, polyether polyol, di (2-ethylhexyl) adipate, aromatic amines, aryl mercuric carboxylate) with Parts A and B in a 1:1 ratio. Optionally, Part C (Plasticizer-ester) may be included at a level of 1% to 150% by weight of the combination of Parts A and B. An acceptable alternative to TC-410 parts A and B is Skin Flex, Part A (aromatic diisocyanate terminated polyoxypropylene glycol mixture); Part B, polyurethane curing agent (polyol-diamine mixture), with Part A and Part B in a 1:2 ratio; and optionally Skin Flex Part C (Plasticizer-ester) at a level of 1% to 150% by weight of the combination of Parts A and B; all available from BJB Industries (Tustin, Calif.).
An example of a substrate made according to the above procedure, where the first layer has an average thickness of about 100 micrometers to about 600 micrometers, the second layer comprises XP-574, and wherein the first negative imprint uses a human forearm to produce a texture on the first surface of the first layer similar to a human forearm, is:
Hardness

Thickness of Thickness of (Shore

Sample Layer 3 (cm) Layer 2 (cm) OOO)¹

5 0.85 0.15 46

¹Average of three measurements.

The substrate is further disclosed in U.S. Ser. No. 11/650,919, filed Jan. 8, 2007, assigned to P&G.

Surface-Pathlength

Pathlength measurements of formed material regions are to be determined by selecting and preparing representative samples of each distinct region and analyzing these samples by means of microscopic image analysis methods.
Samples are to be selected so as to be representative of each region's surface geometry. Generally, the transition regions should be avoided since they would normally contain features of -both the first and second regions. The sample to be measured is cut and separated from the region of interest. The “measured edge” is to be cut parallel to a specified axis of elongation. Usually this axis is parallel to the formed primary-axis of either the first region or the second region. An unstrained sample length of one-half inch is to be “gauge marked” perpendicular to the “measured edge”: while attached to the web package material, and then accurately cut and removed from the web package material.
Measurement samples are then mounted onto the long-edge of a microscopic glass slide. The “measured edge” is to extend slightly (approximately 1 mm) outward from the slide edge. A thin layer of pressure-sensitive adhesive is applied to the glass face-edge to provide a suitable sample support means. For highly formed sample regions it has been found desirable to gently extend the sample in its axial direction (without imposing significant force) simultaneous to facilitate contact and attachment of the sample to the slide-edge. This allows improved edge identification during image analysis and avoids possible “crumpled” edge portions that require additional interpretation analysis.
Images of each sample are to be obtained as “measured edge” views taken with the support slide “edge on” using suitable microscopic measuring means of sufficient quality and magnification. Data is obtained using the following equipment; Keyence VH-6100 (20×Lens) video unit, with video-image prints made with a Sony Video printer Mavigraph unit. Video prints were image-scanned with a Hewlett Packard ScanJet IIP scanner. Image analysis was on a MacIntosh IICi computer utilizing the software NIH MAC Image version 1.45.
Using this equipment, a calibration image initially taken of a grid scale length of 0.500″ with 0.005″ increment-marks to be used for calibration setting of the computer image analysis program. All samples to be measured are then video-imaged and video-image printed. Next, all video-prints are image-scanned at 100 dpi (256-level gray scale) into a suitable Mac image-file format. Finally, each image-file (including calibration file) is analyzed utilizing Mac Image 1.45 computer program. All samples are measured with freehand line-measurement tool selected. Samples are measured on both side-edges and the lengths are recorded. Simple film-like (thin & constant thickness) samples require only one side-edge to be measured. Laminate and thick foam samples are measured on both side-edges. Length measurement tracings are to be made along the full gauge length of a cut sample. In cases of highly deformed samples, multiple (partially overlapping) images may be required to cover the entire cut sample. In these cases, select characteristic features common to both overlapping-images and utilize as “markers” to permit image length readings to adjoin but not overlap.
The final determination of surface-pathlength for each region is obtained by averaging the lengths of five (5) separate ½″ gauge-samples of each region. Each gauge-sample “surface-pathlength”is to be the average of both side-edge surface-pathlengths.
While the test method described above is useful for many of the web package materials of the present invention it is recognized that the test method may have to be modified to accommodate some of the more complex web package materials within the scope of the present invention.

Poisson's Lateral Contraction Effect

The Poisson's lateral contraction effect is measured on an Instron Model 1122, as available from Instron Corporation of Canton, Mass., which is interfaced to a Gateway 2000 486/33 Hz computer available from Gateway 2000 of N. Sioux City, S. Dak., using Test Works™. software which is available from Sintech, Inc. of Research Triangle Park, N.C. All essential parameters needed for testing are input in the TestWorks™. software for each test. Data collection is accomplished through a combination of manual sample width measurements, and elongation measurements made within TestWorks™.
The samples used for this test are 1″ wide×4″ long with the long axis of the sample cut parallel to the direction of the first region of the sample. The sample should be cut with a sharp knife or suitably sharp cutting device designed to cut a precise 1″ wide sample. It is important that a “representative sample” should be cut so that an area representative of the symmetry of the overall pattern of the deformed region is represented. There will be cases (due to variations in either the size of the deformed portion or the relative geometries of regions 1 and 2) in which it will be necessary to cut either larger or smaller samples than is suggested herein. In this case, it is very important to note (along with any data reported) the size of the sample, which area of the deformed region it was taken from and in an embodiment include a schematic of the representative area used for the sample. In general, an “aspect ratio” of (2:1) for the actual extended tensile portion (11:w1) is to be maintained if possible. Five samples are tested.
The grips of the Instron consist of air actuated grips designed to concentrate the entire gripping force along a single line perpendicular to the direction of testing elongation having one flat surface and an opposing face from which protrudes a half round. No slippage should be permitted between the sample and the grips. The distance between the lines of gripping force should be 2″ as measured by a steel rule held beside the grips. This distance will be referred to from here on as the “gauge length”.
The sample is mounted in the grips with its long axis perpendicular to the direction of applied elongation. An area representative of the overall pattern geometry should be symmetrically centered between the grips. The crosshead speed is set to 10 in/min. The crosshead moves to the specified strain (measurements are made at both 20 and 60% elongation). The width of the sample at its narrowest point (w2) is measured to the nearest 0.02″ using a steel rule. The elongation in the direction of applied extension is recorded to the nearest 0.02″ on the TestWorks software. The Poisson's Lateral Contraction Effect (PLCE) is calculated using the following formula:
$P L C E = \frac{\frac{[w 2 - w 1]}{w 1}}{\frac{[l 2 - l 1]}{l 1}}$

- where w2=The width of the sample under an applied longitudinal elongation;
- w1=The original width of the sample;
- l2=The length of the sample under an applied longitudinal elongation; and
- l1=The original length of the sample (gauge length);

Measurements are made at both 20 and 60% elongation using five different samples for each given elongation. The PLCE at a given percent elongation is the average of five measurements.
While the test method described above is useful for many of the web package materials of the present invention it is recognized that the test method may have to be modified to accommodate some of the more complex web package materials within the scope of the present invention.
Tensile Test The tensile test is used for measuring force versus percent elongation properties and percent available stretch of a material. The tests are performed on an Instron Model 1122, available from Instron Corporation of Canton, Mass. which is interfaced to a Gateway 2000 486/33 Hz computer available from Gateway 2000 of N. Sioux City, S. Dak., using TestWorks™. software which is available from Sintech, Inc. of Research Triangle Park, N.C. All essential parameters needed for testing are input in the TestWorks™. software for each test. Also, all data collection, data analysis and graphing are done using the TestWorks™. software.
The samples used for this test are 1″ wide×4″ long with the long axis of the sample cut parallel to the direction of maximum extensibility of the sample. The sample should be cut with a sharp exacto knife or some suitably sharp cutting device design to cut a precise 1″ wide sample. (If there is more than one direction of extensibility of the material, samples should be taken parallel to representative direction of elongation). The sample Should be cut so that an area representative of the symmetry of the overall pattern of the deformed region is represented. There will be cases (due to variations in either the size of the deformed portion or the relative geometries of regions 1 and 2) in which it will be necessary to cut either larger or smaller samples than is suggested herein. In this case, it is very important to note (along with any data reported) the size of the sample, which area of the deformed region it was taken from and in an embodiment include a schematic of the representative area used for the sample. Three samples of a given material are tested.
The grips of the Instron consist of air actuated grips designed to concentrate the entire gripping force along a single line perpendicular to the direction of testing stress having one flat surface and an opposing face from which protrudes a half round to minimize slippage of the sample. The distance between the lines of gripping force should be 2″ as measured by a steel rule held beside the grips. This distance will be referred to from hereon as the “gauge length”. The sample is mounted in the grips with its long axis perpendicular to the direction of applied percent elongation. The crosshead speed is set to 10 in/min. The crosshead elongates the sample until the sample breaks at which point the crosshead stops and returns to its original position (0% elongation).
Graphs of the restive force-elongation curve is shown in FIG. 2. The percent available stretch is the point at which there is an inflection in the force—elongation curve, beyond which point there is a rapid increase in the amount of force required to elongate the sample further. The average of the percent available stretch for three samples is recorded.
While the test method described above is useful for many of the web package materials of the present invention it is recognized that the test method may have to be modified to accommodate some of the more complex web package materials within the scope of the present invention.
The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm”.
All documents cited in the Detailed Description of the Invention are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention. To the extent that any meaning or definition of a term in this written document conflicts with any meaning or definition of the term in a document incorporated by reference, the meaning or definition assigned to the term in this written document shall govern.
While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.

Claims

1. A package comprising:

(a) one or more absorbent articles;

(b) an outer package for the absorbent articles, comprising a web package material comprising at least two distinct regions comprising a first region and a second region being comprised of the same material composition, the first region undergoing a substantially molecular-level deformation and the second region initially undergoing a substantially geometric deformation when the web package material is subjected to an applied elongation along at least one axis; and

wherein the first region and the second region are positioned on one or more grip areas of the outer package, wherein only a portion of the outer package comprises first and second regions.

2. The package of claim 1 wherein the web package material has an available stretch and the second region has a limit to the available stretch.

3. The package of claim 1 wherein the web package material has an Energy Ratio of greater than about 1.

4. The package of claim 1 wherein the web package material has a Deflection Ratio of greater than about 1.

5. The package of claim 1 wherein the web package material has a COF Ratio of greater than about 1.

6. The package of claim 5 wherein the web package material has a COF Ratio of greater than about 1.4.

7. The package of claim 1 wherein the grip area comprises about 5% to about 80% of the total outward facing surface area of the outer package.

8. The package of claim 7 wherein the grips areas comprise top grip area, side grip area, bottom grip area, gusseted grip area, and combinations thereof.

9. The package of claim 1 wherein the first region and the second region are distinct from one another.

10. The package of claim 1 wherein the web package material comprises polyethylene. polypropylene, and combinations thereof.

11. The package of claim 1 wherein the web package material is a laminate or coextrusion of two or more materials.

12. The package of claim 1 wherein the absorbent articles are in roll form comprising paper towels, toilet tissue, facial tissue, and combinations thereof, and the package comprises from about 1 to about 90 rolls.

13. The package of claim 12 comprising from about 4 rolls to about 36 rolls.

14. A package comprising:

(a) a plurality of absorbent articles;

(b) an outer package for the absorbent articles, comprising a web package material, the web package material exhibiting an elastic-like behavior along at least one axis, the web package material comprising: a plurality of first regions and a plurality of second regions, the first region and the second region being comprised of the same material composition and each having an untensioned projected pathlength,

a portion of the first regions extending in a first direction while the remainder of the first regions extend in a second direction, the angles between the first and second directions ranging from about 45° to about 135°, the first regions forming a boundary completely surrounding the second regions, the second regions comprising a plurality of raised rib-like elements, the first region undergoing a molecular-level and geometric deformation and the second region initially undergoing a substantially geometric deformation when the web package material is subjected to an applied elongation in a direction substantial parallel to the axis, and

wherein the first region and the second region are positioned on one or more grip areas of the outer package and wherein only a portion of the outer package comprises first and second regions.

15. The package of claim 14 wherein the web package material has an available stretch and the second region has a limit to the available stretch.

16. The package of claim 14 wherein the web package material has an Energy Ratio of greater than about 1.

17. The package of claim 14 wherein the web package material has a Deflection Ratio of greater than about 1.

18. The package of claim 14 wherein the web package material has a COF Ratio of greater than about 1.

19. The package of claim 18 wherein the web package material has a COF Ratio of greater than about 1.4.

20. The package of claim 14 wherein the grip area comprises from about 5% to about 80% of the total outward facing surface area of the outer package.

21. The package of claim 20 wherein the grips areas comprise top grip area, side grip area, bottom grip area, gusseted grip area, and combinations thereof.

22. The package of 14 wherein the first region is substantially free of the rib-like elements wherein the rib-like elements have a major axis and a minor axis.