Method for making an apertured web

Note: Within nine months ofthe publication ofthe mention ofthe grant ofthe European patent in the European Patent Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the Implementing Regulations. Notice of opposition shall nőt be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).

Printed by Jouve, 75001 PARIS (FR)

EP 2 596 923 Β1

Description

FIELD OF THE INVENTION [0001] The present invention relates to methods for making apertured webs. Specifically, the method can be used to make three-dimensional apertured films, nonwovens, and laminates thereofwith apertures having minimál aspect ratios.

BACKGROUND OF THE INVENTION [0002] Apertured webs are utilized in a wide variety of industrial and consumer products. For example, apertured films or apertured nonwovens are known for use in disposable absorbent articles such as disposable diapers and feminine hygiene articles such as sanitary napkins, and the like. Such articles typically have a fluid pervious topsheet, a fluid impervious breathable backsheet, and an absorbent core disposed between the topsheet and the backsheet. An apertured film can be made to form a fluid pervious topsheet and/or the fluid impervious breathable backsheet.

[0003] U.S. Patent Application No. 2006/0087053 published April 27, 2006 discloses a method for making apertures in a precursor web by moving the web matéria! through a nip ofthe counter-rotating, intermeshing rollers, wherein a first roller comprises circumferentially-extending ridges and grooves, and a second roller comprises teeth being tapered from a base to a tip which are joined to the second roller at the base. The base of the tooth has a cross-sectional length dimension greater than a cross-sectional width dimension. Apertures are formed in the precursor web matéria! as the teeth on one ofthe rollers intermesh with grooves on the other ofthe rollers. The process provides an efficient and cost effective means of forming apertures in a web; however, the size and shape ofthe apertures is limited by the shape and orientation of the teeth in the second roller as well as the orientation of the long chain molecules forming the film. For instance, extruded films have molecular orientations where a majority ofthe long chain molecules are oriented in the machine direction, which for an extruded film is the path that the film follows through the extrusion process. The cross sectional length ofthe teeth on the second roller ofthe counter rotating rollers is alsó aligned in the machine direction. As a result, when forming apertures in extruded films, the process tends to produce apertures resembling slits. Although slits may be acceptable for somé applications, apertures resembling óval holes are typically preferred.

[0004] US 2005/0064136 A1 discloses an aperture film web. The web comprises a plurality of first regions having a first molecular orientation and a plurality of second regions having a second molecular orientation, the first and second regions being in an alternating and contiguous generally linear relationship in a first direction, the second molecular orientation being generally orthogonal to the first direction, and wherein the second region comprises opening defining apertures therein. This document can be seen as disclosing a method for making apertures in a web, the method comprising, providing a precursor web matéria! having a machine direction (MD) and a cross machine direction (CD), the web having a predominant molecular orientation in the machine direction (MD); providing a forming apparátus; and moving the precursor web matéria! through the forming apparátus, wherein the forming apparátus penetrates the web forming apertures therein the forming apparátus comprising pair of rollers forming a nip therebetween.

[0005] Accordingly, there is a need for a process for producing apertures in a film orfilm nonwoven laminate that can overcome the effect offilm molecular orientation and produce apertures resembling óval holes rather than slits.

SUMMARY OF THE INVENTION [0006] A method for making apertures in a web is disclosed where the apertures produced in the web more closely resemble an óval hole rather than a síit. The resulting web exhibits improved fluid acquisition capability, compression resistance and aesthetics. The method is defined in claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS [0007]

FIG. 1 is a schematic representation ofa process ofthe present invention.

FIG. 2 is perspective representation ofan apparátus ofthe present invention.

FIG. 3 is a cross-sectional representation ofa portion ofthe apparátus shown in FIG. 2.

FIG. 4 is a schematic representation of another embodiment of a process and apparátus of the present invention. FIG. 5 is a perspective view of a portion of the apparátus shown in FIG. 2 or FIG. 8.

EP 2 596 923 Β1

FIG. 6 is a magnified perspective view of a portion ofthe apparátus shown in FIG. 9.

FIG. 7 is a perspective view of an alternative configuration fór teeth on the apparátus shown in FIG. 2.

FIG. 8 is a perspective view of a portion of the apparátus shown in FIG. 2.

FIG. 9 is a top view ofthe portion ofthe apparátus shown in FIG. 12.

FIG. 10 is a plán view of a portion of the apparátus shown in FIG. 12.

FIG. 11 is a photograph ofa highly magnified portion ofan apertured web made bythe process ofthe present invention. FIG. 12 is a cross-sectional view of the apertured web of FIG. 12.

FIG. 13 is a photograph ofa highly magnified portion ofan apertured web made bythe process ofthe present invention. FIG. 14 is a cross-sectional view of the apertured web of FIG. 14.

FIG. 15a and 15b are photomicrographs of the apertures formed in samples 1 and 2, respectively, in Example 1. FIG. 16a through 16e are photomicrographs ofthe apertures formed in samples 3 through 7, respectively, in Example 2.

FIG. 17 is a cross-sectional representation ofa portion ofan incremental stretching apparátus.

FIG. 18a through 18d are photomicrographs ofthe apertures formed in samples 8 through 11, respectively in Example 4.

FIG. 19a and 19b are photomicrographs ofthe apertures formed in samples 12 and 13, respectively in Example 5. FIGS. 20A through 20C are schematic representations of various alternative laminate web configurations.

DETAILED DESCRIPTION OF THE INVENTION

Definitions:

[0008] As used herein and in the claims, the term comprising is inclusive or open-ended and does nőt exclude additional unrecited elements, compositional components, or method steps.

[0009] Machine direction or MD is the direction parallel to the direction of travel of the web as it moves through the manufacturing process. Directions within ±45 degrees ofthe MD are considered to be machine directional.

[0010] The cross machine direction or CD is the direction substantially perpendieuíar to the MD and in the pláne generally defined by the web. Directions within 45 degrees ofthe cross direction are considered to be cross directional. [0011] As used herein the term activation means any process by which tensile strain produced by intermeshing teeth and grooves causes intermediate web sections to stretch or extend. Such processes have been found useful in the production of many articles including breathable films, stretch composites, apertured materials and textured materials. Fór nonwoven webs, the stretching can cause fiber reorientation, a reduction in basis weight, and/or controlled fiber destruction in the intermediate web sections. Fór example, a common activation method is the process known in the art as ring rolling.

[0012] As used herein the term activation member means a device including teeth and grooves fór performing activation.

[0013] As used herein the term deformation zone means an area where teeth and grooves of opposing activation members intermesh causing activation.

[0014] As used herein the term path length means the length ofthe deformation zone formed by intermeshing teeth and grooves of opposing activation members.

[0015] As used herein depth of engagement means the extent to which intermeshing teeth and grooves of opposing activation members extend intő one another.

[0016] As used herein, the term nonwoven web refers to a web having a structure of individual fibers or threads which are interlaid, bút nőt in a repeating pattern as in a woven or knitted fabric, which do nőt typically have randomly oriented fibers. Nonwoven webs or fabrics have been formed from many processes, such as, fór example, meltblowing processes, spunbonding processes, hydroentangling, and bonded carded web processes, including carded thermal bonding. The basis weight of nonwoven fabrics is usually expressed in grams per square meter (gsm). The basis weight of the laminate web is the combined basis weight of the constituent layers and any other added components. Fiber diameters are usually expressed in microns; fiber size can alsó be expressed in denier, which is a unit of weight per length of fiber. The basis weight of laminate webs suitable fór use in the present invention can rangé from 6 gsm to 400 gsm, depending on the ultimate use of the web. Fór use as a hand towel, fór example, both a first web and a second web can be a nonwoven web having a basis weight of between 18 gsm and 500 gsm.

[0017] The constituent fibers ofa nonwoven web can be polymer fibers, and can be monocomponent, bicomponent, and/or biconstituent, non-round (e.g., capillary channei fibers), and can have major cross-sectional dimensions (e.g., diameter fór round fibers) ranging from 0.1-500 microns. The constituent fibers of the nonwoven web may alsó be a mixture of different fiber types, differing in such features as chemistry (e.g. PE and PP), components (mono- and bi-), denier (micro denier and >20 denier), shape (i.e. capillary and round) and the like. The constituent fibers can rangé from about 0.1 denier to about 100 denier.

EP 2 596 923 Β1 [0018] As used herein, spunbondfibers refers to relatively small diameterfibers which are formed by extruding molten thermoplastic matéria! as filaments from a plurality of fine, usuaiiy circular capillaries of a spinneret with the diameter of the extruded filaments then being rapidly reduced. Spunbond fibers are generally nőt tacky when they are deposited on a collecting surface. Spunbond fibers are generally continuous and have average diameters (from a sample of at least 10) larger than 7 microns, and more particularly, between about 10 and 40 microns.

[0019] As used herein, the term meltblowing refers to a proeess in which fibers are formed by extruding a molten thermoplastic matéria! through a plurality of fine, usuaiiy circular, die capillaries as molten threads or filaments intő converging high velocity, usuaiiy heated, gas (for example air) streams which attenuate the filaments of molten thermoplastic matéria! to reduce their diameter, which may be to microfiber diameter. Thereafter, the meltblown fibers are carried by the high velocity gas stream and are deposited on a collecting surface, often while still tacky, to form a web of randomly dispersed meltblown fibers. Meltblown fibers are microfibers which may be continuous or discontinuous and are generally smaller than 10 microns in average diameter.

[0020] As used herein, the term polymer generally includes, bút is nőt limited to, homopolymers, copolymers, such as for example, block, graft, random and alternating copolymers, terpolymers, etc., and blends and modifications thereof. In addition, unless otherwise specifically limited, the term polymer includes all possibie geometric configurations ofthe matéria!. The configurations include, bút are nőt limited to, isotactic, atactic, syndiotactic, and random symmetries. [0021] As used herein, the term monocomponent fiber refers to a fiber formed from one or more extruders using oniy one polymer. This is nőt meant to exclude fibers formed from one polymer to which small amounts of additives have been added for coloration, antistatic properties, lubrication, hydrophilicity, etc. These additives, for example titanium dioxide for coloration, are generally present in an amount less than about 5 weight percent and more typically about 2 weight percent.

[0022] As used herein, the term bicomponent fibers refers to fibers which have been formed from at least two different polymers extruded from separate extruders bút spun together to form one fiber. Bicomponent fibers are alsó sometimes referred to as conjugate fibers or multicomponentfibers. The polymers are arranged in substantially constantly positioned distinct zones across the cross-section of the bicomponent fibers and extend continuously along the length of the bicomponent fibers. The configuration of such a bicomponent fiber may be, for example, a sheath/core arrangement wherein one polymer is surrounded by another, or may be a side-by-side arrangement, a pie arrangement, or an islandsin-the-sea arrangement.

[0023] As used herein, the term biconstituent fibers refers to fibers which have been formed from at least two polymers extruded from the same extruder as a blend. Biconstituent fibers do nőt have the various polymer components arranged in relatively constantly positioned distinct zones across the cross sectional area of the fiber and the various polymers are usuaiiy nőt continuous along the entire length of the fiber, instead usuaiiy forming fibers which start and end at random. Biconstituent fibers are sometimes alsó referred to as multiconstituent fibers.

[0024] As used herein, the term non-round fibers describes fibers having a non-round cross-section, and include shaped fibers and capillary channel fibers. Such fibers can be solid or hollow, and they can be tri-lobal, delta-shaped, and may be fibers having capillary channels on their outer surfaces. The capillary channels can be of various crosssectional shapes such as U-shaped, H-shaped, C-shaped and V-shaped. One preferred capillary channel fiber is T-401, designated as 4DG fiber available from Fiber Innovation Technologies, Johnson City, TN. T-401 fiber is a polyethylene terephthalate (PET polyester).

[0025] As used herein, the term molecular orientation describes the degree to which the polymer chains or crystals lie along a particular direction.

[0026] As used herein the term predominant molecular orientation describes the degree to which a majority of the polymer chains lie along a particular direction.

[0027] As used herein the term plastic deformation is deformation that remains in a matéria! after the load causing the deformation is removed. Plastic deformation is the permanent part of the deformation beyond an elastic limit of a matéria!.

[0028] Regarding all numerical ranges disclosed herein, it shouid be understood that every maximum numerical limitation given throughout this specification includes every lower numerical limitation, as if such lower numerical limitations were expressly written herein. In addition, every minimum numerical limitation given throughout this specification will include every higher numerical limitation, as ifsuch higher numerical limitations were expressly written herein. Further, every numerical rangé given throughout this specification will include every narrower numerical rangé that falls within such broader numerical rangé and will alsó encompass each individual number within the numerical rangé, as ifsuch narrower numerical ranges and individual numbers were all expressly written herein.

[0029] The present invention will be described with respect to a method and apparátus used for making an apertured web. The apertured web can be an apertured film or an apertured laminate comprising a film and nonwoven. Apertures can include micro apertures and macro apertures, the former being substantially invisible to the unaided naked eye of an observerfrom approximately 1 meter away in ordinary indoor lighting and the latter being visible undersuch conditions. Micro apertures and/or other embossing or texturing can be formed prior to Processing by the apparátus of the present

EP 2 596 923 Β1 invention. Apertured web can be used in disposable absorbent articles such as bandages, wraps, incontinence devices, diapers, sanitary napkins, pantiliners, tampons, and hemorrhoid treatment pads, as well as other consumer products such as floor cleaning sheets, body wipes, and laundry sheets. In addition, webs ofthe present invention can be utilized as perforated webs in automotive, agricultural, electrical, or industriai applications.

[0030] One apparátus ofthe present invention is shown schematically in FIG. 1. Precursor web 20 is moved in the machine direction (MD) to forming apparátus 150 where apertures 6 are formed producing apertured web 1. Precursor web 20 can be supplied from a supply roll 152 (or supply rolls, as needed for multiple web laminates) or any other supply means, such as festooned webs, as is known in the art. In one embodiment, precursor web 20 can be supplied directly from a web making apparátus, such as a polymer film extruder. Subsequent to formation, apertured web 1 can be taken up on a supply roll 160 for storage and further Processing as a component in other products. Alternatively, apertured web 1 can be conveyed directly to further post Processing, including a converting operation for incorporation intő a finished product, such as a disposable absorbent product.

[0031] As shown in FIG. 1, apertured web 1 can be formed from a generally planar, two dimensional precursor web 20 having a first surface 12 and a second surface 14. Precursor web 20 can be a polymer film or a laminate ofa polymer film and a nonwoven web. First surface 12 corresponds to a first side of precursor web 20, as well as a first side of apertured web 1. Second surface 14 corresponds to a second side of precursor web 20, as well as a second side of apertured web 1. In generál, the term side is used herein in the common usage ofthe term to describe the two major surfaces of generally two-dimensional webs, such as films. Of course, in a composite or laminate structure, the first surface 12 ofthe apertured web 1 is the first side ofone ofthe outermost layers or plies, and the second surface 14 is the second side of the other outermost layer or ply.

[0032] Precursor web 20 can be a polymeric film web. In one embodiment precursor web 20 can be a polymeric web suitable for use as a topsheet in a disposable absorbent product, as is known in the art. Polymeric film webs can be deformable. Deformable matéria! as used herein describes a matéria! which, when stretched beyond its elastic limit, will substantially retain its newly formed conformation. Such deformable materials may be chemically homogeneous or heterogeneous, such as homopolymers and polymer blends, structurally homogeneous or heterogeneous, such as piain sheets or laminates, or any combination of such materials. The processes of the present invention are used to form materials comprising a polymeric film. Such materials include polymeric films alone or laminate comprising polymeric films and other materials such as nonwovens.

[0033] Deformable polymeric film webs utilized in the process of the present invention can have a transformation temperature rangé where changes in the solid state molecular structure of the matéria! occur, such as a change in crystalline structure or a change from solid to molten state. As a consequence, above the transformation temperature rangé, certain physical properties ofthe matéria! are substantially altered. For a thermoplastic semicrystalline film, the transformation temperature rangé may be the glass transition temperature rangé ofthe film, above which the polymer becomes rubbery and capable of elastic or plastic deformation without fracture orthe melt temperature rangé ofthe film, above which the film is in a molten state and loses substantially all previous thermo-mechanical history.

[0034] Polymeric film webs can comprise thermoplastic polymers having characteristic rheological properties which depend on their composition and temperature. Below their glass transition temperature, such thermoplastic polymers can be quite hard and stiff and often brittle. Below this glass transition temperature, the molecules are in rigid, fixed positions. Above the glass transition temperature bút below the melt temperature rangé, thermoplastic polymers exhibit viscoelasticity. In this temperature rangé, the thermoplastic matéria! generally has a certain degree of crystallinity, and is generallyflexible and fosomé degree deformable under a force. The deformabilityof such a thermoplastic is dependent on the rateof deformation, amount (dimensional quantity) of deformation, length of time it isdeformed, and its temperature. In one embodiment, the processes ofthe present invention can be utilized to form materials comprising thermoplastic polymer, especially thermoplastic film, which is within this viscoelastic temperature rangé.

[0035] Polymeric film webs can comprise a certain amount of ductility. Ductility, as used herein, is the amount of permanent, unrecoverable, plastic strain which occurs when a matéria! is deformed, prior to failure (rupture, breakage, or separation) of the matéria!. Ductility is dependent upon the rate of strain that is applied to the matéria!. Materials formed in the process of the present invention can have a minimum ductility of at least about 10%, or at least about 50%, or at least about 100%, or at least about 200% or at least about 500%.

[0036] Polymeric film webs utilized in the present invention can include materials normally extruded or cast as films such as polyolefins, nylons, polyesters, and the like. Such films can be thermoplastic materials such as polyethylene, low density polyethylene, linear low density polyethylene, polypropylenes and copolymers and blends containing substantial fractions of these materials. Such films can be treated with surface modifying agents to impart hydrophilic or hydrophobic properties, such as imparting a lotus effect. Polymeric film webs can be single layered or multilayered fiat films. As noted below, polymeric film webs can be textured, embossed, or otherwise altered from a strictly fiat, planar configuration.

[0037] Physical properties ofpolymericfilms, in particularthe modulus, depend on polymer molecular orientation which is previously defined as the degree to which polymer chains lie along a particular direction. The molecular orientation

EP 2 596 923 Β1 ofa film can be determined according to ASTM method D2732-03. The test method covers determination ofthe degree of unrestrained linear thermal shrinkage at given specimen temperature of plastic film and sheeting of 0.030 in (0.76 mm) thickness or less. Film specimens having a predominant moleeuiar orientation will shrink primarily in the direction of the predominant moleeuiar orientation and to a lesser extent in the direction perpendícular thereto.

[0038] A biaxially oriented polymeric film has a substantially random orientation with respect to the MD and the CD. By substantially random moleeuiar orientation it is meant that due to conditions during film Processing, there is nőt a significantly higher amount of long chain molecules oriented in the MD than in the CD. In other words the number of long chain molecules in the MD and the CD is about the same. As a result, films having a random moleeuiar orientation can exhibit similar properties, such as modulus, in the MD and the CD. A blown film can be an example of a biaxially oriented polymeric film. In contrast, films having a predominant moleeuiar orientation have a higher amount of long chain molecules oriented in a particular direction. For instance, extruded films can have a higher amount of long chain molecules oriented in the MD than in the CD. A cast film is an example of a film that has a predominant moleeuiar orientation in the MD. The moleeuiar orientation of a polymeric film can be modified by heating and/or plastically deforming the film. For instance, a film having a predominant moleeuiar orientation in the MD can be strained and plastically deformed in the CD changing the orientation ofthe long chain polymers to a biaxial or CD oriented polymeric film.

[0039] Precursor web 20 can be a composite or a laminate of two or more precursor webs, and can comprise, for example, a combination of polymer films and nonwoven webs. Nonwoven webs orfabrics have been formed from many known processes, such as, for example, air laying processes, meltblowing processes, spunbonding processes, hydroentangling processes, spunlacing processes, and bonded carded web processes. Alsó, multi-layerwebs, such asspunbondmeltblown-spunbond (SMS) webs and the like (e.g., SMMS, SSMS) made by multiple beam spunbond processes, can be utilized. It is nőt necessary that each component (i.e., the spunbond or meltblown components) be the same polymer. Therefore, in an SMS web, it is nőt necessary that the spunbond and the meltblown layers comprise the same polymer. [0040] The constituent fibers of nonwoven webs can be polymer fibers, and can be monocomponent, bicomponent and/or biconstituent fibers, hollow fibers, non-round fibers (e.g., shaped (e.g., trilobal) fibers or capillary channel fibers), and can have major cross-sectional dimensions (e.g., diameter for round fibers, long axis for elliptical shaped fibers, longest straight line dimension for irregular shapes) ranging from 0.1-500 microns in 1 micron increments.

[0041] Precursorweb 20 can be preheated by means known in the art, such as by radiant heating, forced air heating, convection heating, or by heating over oil-heated rollers. Precursor web 20 can be pre-printed with indicia, designs, logos, or other visible or invisible print patterns. For example, designs and colors can be printed by means known in the art, such as by ink-jet printing, gravure printing, flexographic printing, or offset printing, to change the color of at least portions of precursor web 20. In addition to printing, precursor web 20 can be treated with coatings, such as with surfactants, lotions, adhesives, and the like. Treating precursorweb 20 can be achieved by means known in the art such as by spraying, siót coating, extruding, or otherwise applying coatings to one or both surfaces.

[0042] Supply roll 152 rotates in the direction indicated by the arrow in FIG. 1 as precursorweb 20 is moved in the machine direction by means known in the art, including over or around any of various idler rollers, tension-control rollers, and the like (all of which are nőt shown) to the nip 116 formed by a pair of counter-rotating, intermeshing rolls 102 and 104. The pair of intermeshing rolls 102 and 104 operate to form apertures in web 20 forming apertured web 1. Intermeshing rolls 102 and 104 are more clearly shown in FIG. 2.

[0043] Referring to FIG. 2, there is shown in more detail the portion of forming apparátus 150 for making apertures in apertured web 1. This portion of apparátus 150 is shown as forming apparátus 100 in FIG. 2, and comprises a pair of steel intermeshing rolls 102 and 104, each rotating about an axis A, the axes A being parallel and in the same pláne. Forming apparátus 100 can be designed such that precursor web 20 remains on roll 104 through a certain angle of rotation, as shown in detail below with respect to FIG. 8, bút FIG. 2 shows in principle what happens as precursorweb 20 goes straight through nip 116 on forming apparátus 100 and exits as apertured web 1. Therefore, while FIG. 2 shows apertured web 1 going straight intő and coming straight out of nip 116, precursor web 20 or apertured web 1 can be partially wrapped on either of rolls 102 or 104 through a predetermined angle of rotation priorto (for precursorweb 20) or after (for apertured web 1) nip 116. For example, after exiting nip 116, apertured web 1 can be directed to be wrapped on roll 104 through a predetermined angle of rotation such that the apertures remain resting over, and fitted onto, teeth 110 of roll 104, as shown in FIG. 8.

[0044] Rollers 102 and 104 can be made of steel or aluminum. In one embodiment, the rollers can be made of stainless steel. In generál, rollers 102 and 104 can be made of corrosion resistant and wear resistant steel.

[0045] Roll 102 can comprise a plurality of ridges 106 and corresponding grooves 108 which can extend unbroken about the entire circumference of roll 102. In somé embodiments, depending on what kind of pattern is desired in apertured web 1, roll 102 can comprise ridges 106 wherein portions have been removed, such as by etching, milling or other machining processes, such that somé or all of ridges 106 are nőt circumferentially continuous, bút have breaks or gaps. The breaks or gaps can be arranged to form a pattern, including simple geometric patterns such as circles or diamonds, bút alsó including complex patterns such as logos and trademarks. In one embodiment, roll 102 can have teeth, similar to the teeth 110 on roll 104, described more fully below. In this manner, it is possible to have three

EP 2 596 923 Β1 dimensional apertures having portions extending outwardly on both sides of apertured web 1. In addition to apertures, various out-of-plane macro-areas of apertures ofweb 1 can be made, including macro-patterns of embossed texture depicting logos and/or designs. In an alternate embodiment, the outer surface of roll 102 can comprise a brush or elastic matéria! such as rubber which allow teeth on mating roll 104 to penetrate at a nip formed between the two rolls.

[0046] Roll 104 is similar to roll 102, bút rather than having ridges that can extend unbroken about the entire circumference, roll 104 comprises a plurality of rows of circumferentially-extending ridges that have been modified to be rows of circumferentially-spaced teeth 110 that extend in spaced relationship about at least a portion of roll 104. The individual rows of teeth 110 of roll 104 are separated by corresponding grooves 112. In operation, rolls 102 and 104 intermesh such that the ridges 106 of roll 102 extend intő the grooves 112 of roll 104 and the teeth 110 of roll 104 extend intő the grooves 108 of roll 102. The intermeshing is shown in greater detail in the cross sectional representation of FIG. 7, discussed below. Both or either of rolls 102 and 104 can be heated by means known in the art such as by incorporating hot oil filled rollers or electrically-heated rollers. Alternatively, both or either of the rolls may be heated by surface convection or by surface radiation.

[0047] Teeth 110 can be joined to roller 104. By joined is meant that teeth can be attached to, such as by welding, compression fit, orotherwisejoined. However, joined alsó includes integrál attachment, as is the case for teeth machined by removing excess matéria! from roller 104. The location at which teeth 110 are joined to roller 104 is the base. At any cross-sectional location parallel to the base each tooth can have a non-round cross-sectional area. In the circumferential direction a cross-sectional length ofthe cross-sectional area (corresponding to the tooth length, as discussed below), is at least two times a cross sectional width, measured perpendicular to the length dimension atthe center ofthe crosssectional area. In an alternate embodiment the teeth may comprise pins that are cylindrical, rectangularor other shapes depending on the corresponding aperture shape desired.

[0048] FIG. 3 shows in cross section a portion ofthe intermeshing rolls 102 and 104 including ridges 106 and representative teeth 110. As shown, teeth 110 have a tooth height TH (note that TH can alsó be applied to ridge 106 height; in a preferred embodiment tooth height and ridge height are equal), and a tooth-to-tooth spacing (or ridge-to-ridge spacing) referred to as the pitch P. As shown, depth of engagement, (DOE) E is a measure ofthe level of intermeshing of rolls 102 and 104 and is measured from tip of ridge 106 to tip of tooth 110. The depth of engagement E, tooth height TH, and pitch P can be varied as desired depending on the properties of precursor web 20 and the desired characteristics of apertured web 1 of the present invention. For example, in generál, to obtain a higher density of volcano-shaped structures 8 or apertures 6 of web 1, the smaller the pitch should be, and the smaller the tooth cross sectional length TL and tooth spacing distance TD should be, as described below.

[0049] It is alsó contemplated that the size, shape, orientation and spacing of the teeth 110 can be varied about the circumference and width of roll 104 to provide for varied apertured web 1 properties and characteristics.

[0050] Additionally, substanoes such as lotions, ink, surfactants, and the like can be sprayed, coated, siót coated, extruded, or otherwise applied to apertured web 1 before or after entering nip 116. Any processes known in the art for such application of treatments can be utilized.

[0051] In one embodiment, apertured web 1 can be formed by Processing a precursor web 20 through an apparátus 200 as shown in FIG. 4. The multi-roller arrangement of apparátus 200 is designed to provide for a predetermined dwell time in which apertured web 1 remains in contact with toothed roller 104 through a predetermined angle of rotation. While the angle of rotation can be optimized depending upon the type offilm, temperature of rollers, and the speed of web travel, in generál the angle ofwrap can be at least 10 degrees and as high as about 270 degrees or more, depending, at least in part, on the relatíve sizes ofthe mating rollers. As shown, precursor web 20 can be guided around various guíde rollers and tensioning members (nőt shown) to guíde roller 105 and onto roll 102A which can have ridges and grooves as described with respect to roller 102 of apparátus 150 in FIG. 1 above. Roller 102A can be heated to aid in forming volcano-shaped structures 8 and apertures 6. In one embodiment, roller 102 can be heated to about 200°F. [0052] As shown in FIG. 4, precursor web 20 enters nip 116A formed by the inter-engagement of meshing rollers 104 and 102A. Roller 104 of apparátus 200 can be a toothed roller as described above with respect to apparátus 150 in FIG. 1. As precursor web 20 passes through nip 116A, teeth 110 on roller 104 press intő and/or through and can pierce precursor web 20 to form volcano-shaped structures 8 and apertures 6. Apertured web 1 then continues in stationary contact with rotating roller 104 until reaching nip 116B formed by the inter-engagement of roller 104 with roller 102B. Roller 102B can have ridges and grooves as described with respect to roller 102 of apparátus 150 in FIG. 1 above. [0053] As apertured web 1 exits nip 116B it is directed off of roller 104, onto roller 102B and over various guíde rollers 105 as necessary before being wound for further Processing, shipping, or piacement for incorporation in a manufactured product. In one embodiment, apertured web 1 is directed intő a manufacturing process for sanitary napkins, wherein apertured web 1 is fed intő the process as a topsheet and joined to other components such as a backsheet web, cut to finished shape, packaged, and shipped to retail outlets. In another embodiment, the web is directed intő a manufacturing process for a diaper product, wherein apertured web 1 is fed intő the process as a backsheet and joined to other components such as a topsheet.

[0054] If apertured web 1 tends to stick to teeth 110 upon being pulled off of roller 104, various Processing aids can

EP 2 596 923 Β1 be added as neeessary. For example, non-stick treatments, such as silicone or fluorocarbon treatments can be added. Various lubricants, surfactants or other Processing aids can be added to the precursor web 20 orto the roller 104. Other methods of aiding the removal of the web from the roller include air knives or brushing. In one embodiment, roller 104 can have an internál chamber and means to provide positive air pressure at the point of web removal onto roller 102B. In generál, control ofthe transition from roller 104 to roller 102B is affected by web speed, relatíve roller speeds (i.e., tangential speed of roller 104 and roller 102B), web tension, and relatíve coefficients offriction. Each of these parameters can be varied as known by those skilled in the art to ensure the desired transfer of apertured web 1 onto roller 102B. [0055] The benefit of having an apparátus like that shown in FIG. 4 is that apertured web 1 experiences an extended amount of time in contact with and nested on teeth 110 of roller 104. In this manner, volcano-shaped structures 8 and apertures 6 have additional time to set and a higher likelihood of retaining a three-dimensional configuration once removed from roller 104. Without being bound by theory, it is believed that by adjusting the circumference of roller 104, the temperature of rollers 102A, 104, and/or 102B, as well as the coefficient offriction of rollers, this longer dwell time can be used to increase the line speed atwhich apertured web 1 can be processed to make permanentthree-dimensional volcano-shaped structures 8. The temperature of rollers 102A, 104, and/or 102B may all be at the same temperature or alternatively at different temperatures. For example, rollers 102A and 104 may be heated while roller 102B is at room temperature or below. In addition, the speeds ofthe various rollers may be maintained at the same speed, or alternately a speed differential between the rollers may be established.

[0056] lf any of the rollers of the apparátus 150 or 200, as described above are to be heated, care must be taken to account for thermal expansion. In one embodiment, the dimensions of ridges, grooves, and/or teeth are machined to accountforthermal expansion, such that the dimensions shown in FIG. 3 and dimensions described herein are dimensions at operating temperature.

[0057] FIG. 5 shows a portion of one embodiment of a roller 104 having a plurality of teeth 110 useful for making an apertured web 1. An enlarged view ofthe teeth 110 shown in FIG. 5 is shown in FIG. 6. As shown in FIG. 6, each tooth 110 has a base 111, a tooth tip 112, a leading edge LE and a trailing edge TE. The tooth tip 112 can be generally pointed, blunt pointed, orotherwise shaped so as to stretch and/or puncture the precursor web 20. Teeth 110 can have generally flattened blade-like shape. That is, as opposed to round, pin-like shapes that are generally round in cross section, teeth 110 can be elongated in one dimension, having generally non-round, elongated cross-sectional configurations. For example, at their base 111, the cross section of teeth 110 can have a tooth length TL and a tooth width TW exhibiting a tooth aspect ratio AR of TL/TW of at Ieast 2, or at Ieast about 3, or at Ieast about 5, or at Ieast about 7, or at Ieast about 10 or greater. In one embodiment, the aspect ratio AR of cross-sectional dimensions remains substantially constant with tooth height.

[0058] In one embodiment of roller 104, teeth 110 can have a uniform cross sectional length dimension TL of about 1.25 mm measured generally from the leading edge LE to the trailing edge TE at the base 111 of the tooth 110, and a tooth cross sectional width TW of about 0.3 mm measured generally perpendicularly to the circumferential length dimension at the base. Teeth can be uniformly spaced from one another circumferentially by a distance TD of about 1.5 mm. For making a soft, fibrous three-dimensional apertured web 1 from a precursor web 20 having a basis weight in the rangé of from about 5 gsm to about 200 gsm, teeth 110 of roll 104 can have a length TL ranging from about 0.5 mm to about 3 mm, a tooth width TW of from about 0.3 mm to about 1 mm, and a spacing TD from about 0.5 mm to about 3 mm, a tooth height TH ranging from about 0.5 mm to about 10 mm, and a pitch P between about 1 mm (0.040 inches) and 2.54 mm (0.100 inches). Depth of engagement E can be from about 0.5 mm to about 5 mm (up to a maximum approaching the tooth height TH).

[0059] Of course, depth of engagement E, pitch P, tooth height TH, spacing TD and tooth cross sectional length TL can each be varied independently of each other to achieve a desired size, spacing, and area density of apertures 6 (number of aperture 6 per unit area of apertured web 1). For example, to make apertured films and nonwovens suitable for use in sanitary napkins and other absorbent articles, tooth cross sectional length TL at the base can rangé between about 2.032 mm to about 3.81 mm; tooth width TW can rangé from about .508 mm to about 1.27 mm; tooth spacing TD can rangé from about 1.0 mm to about 1.94 mm; pitch P can rangé from about 1.106 mm to about 2.54 mm; and tooth height TH can be from about 2.032 mm to about 6.858 mm. Depth of engagement E can be from about 0.5 mm to about 5 mm. The radius of curvature R of the tooth tip 112 can be from 0.001 mm to about 0.009 mm. Without being bound by theory, it is believed that tooth length TL at the base can rangé between about 0.254 mm to about 12.7 mm; tooth width TW can rangé from about 0.254 mm to about 5.08 mm; tooth spacing TD can rangé from about 0.0 mm to about 25.4 mm (or more); pitch P can rangé from about 1.106 mm to about 7.62 mm; tooth height TH can rangé from 0.254 mm to about 18 mm; and depth of engagement E can rangé from 0.254 mm to about 6.35 mm. For each ofthe ranges disclosed, it is disclosed herein that the dimensions can vary within the rangé in increments of 0.001 mm from the minimum dimension to the maximum dimension, such that the present disclosure is teaching the rangé limits and every dimension in between in 0.001 mm increments (except for radius of curvature R, in which increments are disclosed as varying in 0.0001 mm increments).

[0060] Without wishing to be bound by theory, and consistent with currently-pending tool designs, it is believed that

EP 2 596 923 Β1 other dimensions are possibíe fór use in the method and apparátus ofthe present invention. Fór example, tooth length TL at the base can rangé can be from about 0.254 mm to about 12.7 mm, and can include 4.42 mm, 4.572 mm and about 5.56 mm; tooth width TW can rangé from about 0.254 mm to about 5.08 mm, and can include 1.78 mm; tooth spacing TD can rangé from about 0.0 mm to about 25.4 mm, and can include 2.032 mm; pitch P can rangé from about 1.106 mm to about 7.62 mm; tooth height TH can rangé from 0.254 mm to about 18 mm, and can include 5.08 mm; and depth of engagement E can rangé from 0.254 mm to about 6.35 mm. Radius of curvature can rangé from about 0.00 mm to about 6.35 mm. Fór each of the ranges disclosed, it is disclosed herein that the dimensions can vary within the rangé in increments of 0.001 mm from the minimum dimension to the maximum dimension, such that the present disclosure is teaching the rangé limits and every dimension in between in 0.001 mm increments (except fór radius of curvature R, in which increments are disclosed as varying in 0.0001 mm increments).

[0061] In one embodiment, to make the volcano-shaped structures 8 and/or apertures 6 of apertured web 1, the LE and TE should taperto a point in a generally pyramidal orfrustro-conical shape which can be described as being shaped like a shark’s tooth. As shown in FIG. 10, the generally pointed pyramidal shark tooth shape can have six sides 114, each side being generally triangular in shape. The vertex of two sides makes up the leading edge LE and the vertex of two sides makes up the trailing edge TE of tooth 110. The vertices ofthe leading or trailing edge can be relatively sharp, or can be machined to have a rounded radius of curvature. The radius of curvature of the tooth tip can be 0,0127 cm (0.005 inches).

[0062] Other tooth shapes can be utilized to make apertures. As shown in FIG. 7, fór example, the generally pyramidal shapes shown in FIG. 5 can be truncated so as to remove the pointedness of tips 112. Truncation can be made at a predetermined distance from base 111 such that a generally flattened region 120 is produced at the distal end of tooth 110. Generally flattened region 120 can have an area shape corresponding to the cross-sectional shape of tooth 110. Thus, generally flattened region 120 can alsó be elongated, that is, having a length dimension greater than a width dimension and an aspect ratio AR corresponding to the aspect ratio of tooth 110. In one embodiment, flattened region 120 can transition to sides 114 at generally sharp vertices, or the transition can be at a radius of curvature, providing fór a smooth, rounded, flattened tooth tip.

[0063] In another embodiment, as shown in FIG. 8, teeth 110 can have at least one edge that extends generally perpendicularly with respect to the surface of roller 104. As shown in the partial perspective view of roller 104 in FIG. 8, fór example, teeth resembling shark fins can have a leading edge LE that angles toward tip tooth 112, and a trailing edge TL that extends generally perpendicular from base 111 toward tip tooth 112. In another embodiment, the tooth 110 can have the same shape, bút the leading and trailing edges reversed such that the generally perpendicular edge is the leading edge.

[0064] FIG. 9 is a top view ofthe portion of roller 104 shown in FIG. 8. Various dimensions are shown in the illustrated embodiment, including the angles produced by the sides 114 making up the leading and trailing edges. Likewise, FIG.

is a detail ofthe teeth shown in FIG. 8 showing representative dimensions. In generál, while the dimensions shown are those currently believed to be beneficial fór making three-dimensional formed films useful as topsheets on disposable absorbent articles, all dimensions can be varied as necessary depending on the desired aperture density, spacing, size, and the web type of precursor web 20.

[0065] Without being bound by theory, it is believed that having relatively sharp tips on teeth 110 permits the teeth 110 to punch through precursorweb 20 cleanly, that is, locally and distinctly, so that the resulting apertured web 1 can be described as being predominantly apertured rather than predominantly embossed. In one embodiment, puncture of precursor web 20 is clean with little deformation ofweb 20, such that the resulting web is a substantially two-dimensional perforated web.

Apertured Film [0066] Two representative three-dimensional apertured formed film webs 1 are shown in the photomicrographs of FIGS. 11-14. FIG.11 shows a portion of a three-dimensional, apertured web 1 made from a generally planar polyethylene film precursor web 20 having a basis weight of approximately 25 grams per square meter. Apertures 6 shown in FIG.

were formed by the action of teeth 110 on a heated roll 104 having stretched and pushed through precursor web 20 to permanently deform precursorweb 20 to form a plurality of diserete, spaced apart volcano-like structures 8 extending outwardly from first side 12. Webs as shown in FIGS. 12-15 can be made by Processing through the nip 116 of rolls 102 and 104 heated to about 200°F. In generál, line speed and sufficient heating of apparátus 100 depends on the size of teeth 110, the angle of wrap on either roll, and/or the type and basis weight ofthe precursorweb 20, all of which can be varied as necessary by means well known in the art.

[0067] As shown in the cross section of FIG. 12, apertures 6 piacé the first side 12 and the second side 14 of apertured web 1 in fluid communication through the volcano-like structures 8. Volcano-like structures 8 comprise a continuous side wall 9 of deformed film having a significant orientation in the Z-direction which can be relatively rigid to resist Zdirection compression in use. The undeformed portions of apertured web 1 of FIGS. 12 and 13 can be fluid impervious.

EP 2 596 923 Β1 [0068] The number of apertures 6 per unit area of apertured web 1, i.e., the area density of apertures 6, can be varied from 1 aperture 6 per square centiméter to as high as 60 apertures 6 per square centiméter. There can be at least 10, or at least 20 apertures 6 per square centiméter, depending on the end use. In generál, the area density need nőt be uniform across the entire area of apertured web 1, bút apertures 6 can be only in certain regions of apertured web 1, such as in regions having predetermined shapes, such as lines, stripes, bands, circles, and the like. In one embodiment, where apertured web 1 is used as a topsheet for a sanitary napkin, for example, apertures 6 can be only in the region corresponding to the Central part ofthe pad where fluid entry occurs.

[0069] As can be understood with respect to forming apparátus 100, therefore, apertures 6 of apertured web 1 are made by mechanically deforming precursor web 20 that can be described as generally planar and two dimensional. By planar and two dimensional is meant simply that the web is fiat relatíve to apertured web 1 that has distinct, out-ofplane, Z-direction three-dimensionality imparted due to the formation of volcano-shaped structures 8. Planar and twodimensional are nőt meant to imply any particular flatness, smoothness ordimensionality. As such, a soft, fibrous nonwoven web can be planar in its as-made condition. As precursor web 20 goes through the nip 116 the teeth 110 of roll 104 entergrooves 108 of roll 102 and simultaneously ürge matéria! out ofthe planeof precursor web 20 toform permanent volcano-like structures 8 and apertures 6. In effect, teeth 110 push or punch through precursor web 20. As the tip of teeth 110 push through precursor web 20 the web matéria! is ürgéd by the teeth 110 out of the pláne of precursor web 20 and is stretched and/or plastically deformed in the Z-direction, resulting in formation of permanent volcano-like structures 8 and apertures 6. The amount of ductility and other matéria! properties of the precursor web, such as the glass transition temperature and crystallinity determine how much relatively permanent three-dimensional deformation the apertured web 1 retains.

[0070] FIGS. 13 and 14 show another embodiment of a three-dimensional apertured web 1 in which the precursor web 20 was nőt a fiat film bút rather was a film that was pre-textured with microscopic aberrations 2. Aberrations 2 can be bumps, embossments, holes, orthe like. In the embodiment shown, aberrations 2 are alsó volcano-shaped microapertures, formed by a hydro forming process. A suitable hydroforming process is the first phase of the multiphase hydroforming process disclosed in US Patent No. 4,609,518, issued to Curro et al. on September 2, 1986. The hydroforming screen utilized for the webs shown in FIGS. 14 and 15 was a 100 mesh screen and the film was obtained from Tredegar Film Products, Térré Haute, IN. Apertures 6 were formed by teeth 110 of roll 104 in apparátus 100.

[0071] As shown in the cross section of FIG. 14, in one embodiment apertures 6 formed by the teeth 110 of roll 104 extend in a direction away from first side 12 while the aberrations 2 such as the micro apertures formed by hydroforming extend away from second side 14. Aberrations 2 can alsó be non-apertured protrusions, fibrils, or embossments to provide texture that provides for a tactile impression ofsoftness. Softness is beneficial when webs 1 are used as topsheets in disposable absorbent articles, and the method disclosed herein forforming volcano-shaped structures 8 and apertures 6 is effective in preserving the micro texture aberrations 2, particularly when the volcano-shaped structures 8 and apertures 6 are made on the disposable absorbent article production line. In this manner, a soft, compliant topsheet for a disposable absorbent article can be achieved when the apertured web 1 is used with the second side 14 having aberrations 2 as the body-facing surface ofthe article.

[0072] The apertures 6 of the film embodiments shown in FIGS. 11-14 were made on an apparátus like that shown in FIG. 2, where the apparátus 100 is arranged to have one patterned roll, e.g., roll 104, and one non-patterned grooved roll 102. However, in certain embodiments it may be preferable to form nip 116 by use of two patterned rolls having either the same or differing patterns, in the same or different corresponding regions of the respective rolls. Such an apparátus can produce webs with apertures 6 protruding from both sides of the apertured web 1, as well as macrotexture, e.g., aberrations, micro-apertures, or micro-patterns, embossed intő the apertured web 1. Likewise, it may be desirable to have multiple apparatuses 100 such that apertured web 1 is re-processed to have additional structures 8 and/or apertures 6. For example, a higher area density of volcano-shaped structures 8 on apertured web 1 can be achieved by Processing precursor web 20 through two or more apparatuses 100.

[0073] lt is alsó contemplated that the size, shape, orientation and spacing of the teeth 110 can be varied about the circumference and width of roll 104 to provide for varied apertured web 1 properties and characteristics. The number, spacing, and size of apertures 6 can be varied by changing the shape, number, spacing, and size of teeth 110 and making corresponding dimensional changes as necessary to roll 104 and/or roll 102. This variation, together with the variation possible in precursor webs 20 and the variation in Processing, such as line speeds, roll temperature, and other post Processing variations, permits many varied apertured webs 1 to be made for many purposes.

[0074] While the size of apertures produced according to the process described herein is related to the corresponding size and shape of the teeth 110 as well as other aforementioned process parameters, it has been found that the actuai shape ofthe apertures is related to the orientation ofthe teeth 110 on roll 104 relatíve to the molecular orientation ofthe long chain molecules forming precursor web 20. In other words, teeth disposed at an angle relatíve to the molecular orientation ofthe film have been found to form óval shaped apertures with aspect ratios (L/W) that are comparably less than the aspect ratios of elongate shaped apertures formed by teeth aligned parallel to the molecular orientation of the film. In fact teeth aligned perpendicular to the molecular orientation of the film have been found to form óval shaped

EP 2 596 923 Β1 apertures with aspect ratios (L/W) approaching 1.0 where as teeth aligned parallel to the moiecular orientation ofthe film can form apertures with aspect ratios exceeding 5.0.

[0075] Nőt to be bound by theory, when a tooth punctures a film web, it cuts or breaks long chain molecules causing the molecules to puli apart. If the teeth are heated, stress relaxation or melting may occur, causing the long chain molecules to shrink while returning to a point of equilibrium. As a result, it is believed that MD oriented teeth effect fewer long chain molecules when puncturing the MD oriented film resulting in slits where as the CD oriented teeth effect more long chain molecules in the MD oriented film resulting in larger and more rounded apertures. Thus, it has been found that the formation of óval shaped apertures with minimál aspect ratios can be achieved by modifying the orientation of the teeth and/or the moiecular orientation of the film so that the relatíve angle between the orientation of the teeth and moiecular orientation ofthe film is greater than 0°, preferably the relatíve angle between the orientation ofthe teeth and moiecular orientation of the film ranges from about 30° to about 90°. More preferably, the relatíve angle is about 90°. [0076] Fór instance, the teeth 110 on roll 104 of forming apparátus 100 shown in FIG. 2 are oriented such that the teeth cross sectional length TL is aligned in the MD. Such MD aligned teeth can produce slitted or elongate shaped apertures in a film having a predominant moiecular orientation in the MD. By comparison, if the teeth 110 were oriented such that the cross sectional length TL ofthe teeth were aligned in the CD, then the teeth would produce óval shaped apertures in a film having a predominant moiecular orientation in the MD. Therefore, the orientation of the teeth on the roll can be arranged to produce apertures in an MD oriented film having minimál aspect ratio and preferably aspect ratios that are less than about 4.0.

EXAMPLE1 [0077] Samples were made by running micro apertured, 100 mesh films against 0.050 inch pitch forming apparátus. Fór sample 1, the teeth were oriented in the MD. Fór sample 2, the teeth were oriented in the CD. Both films were activated at a temperature of 75°C and at a line speed of 50 feet/min. FIG. 15a of Sample 1 shows the resultant apertures produced by the MD oriented teeth and FIG. 15b of sample 2 is a result of orienting the teeth in the CD. As shown, the aperture length remains the same while the width is increased thereby decreasing the aspect ratio.

<td colspan="5"> Table 1</td>

<td> Sample</td><td> Average Aperture Length (mm)</td><td> Average Aperture Width (mm)</td><td> Average Aperture Aspect Ratio</td><td> FIG.</td>

<td> 1</td><td> 1.43</td><td> 0.28</td><td> 5.1</td><td> 15a</td>

<td> 2</td><td> 1.44</td><td> 0.81</td><td> 1.8</td><td> 15b</td>

EXAMPLE 2 [0078] Samples were apertured a by orienting the film samples relatíve to the teeth so that the effects ofthe orientation ofthe teeth relatíve to the moiecular orientation ofthe film could be assessed. 100 mesh film samples were apertured using 0.050 inch pitch intermeshing piates on the high speed research press described in United States Patent No. 7,024,939 and United States Patent No. 7,062,983. Samples were cut intő rectangular pieces (50 mm x 200 mm) fór testing. Five different samples were prepared, each cut at a different angle relatíve to the rnachine direction ofthe film. Fór sample 3, the sample was cut in alignment with the rnachine direction of the film, and so is designated to have an orientation angle of 0°. Sample 7 was cut with the long dimension ofthe sample aligned to the cross direction ofthe film and so is designated to have an orientation angle of 90°. Other samples were cut at 30, 45 and 60 ° relatíve to the rnachine direction ofthe film. Fór testing, the long dimension ofthe samples was aligned with the cross-sectional length dimension of the teeth on the intermeshing piates. In this way, the angle between the cross-sectional length dimension ofthe teeth, and the predominant moiecular orientation (MD) ofthe film was varied to determine the impact on aperture quality. The temperature of both tooling piates was set at 100 °C, and conditions were set up to mimic a 205.84 mm roll diameter, a web speed of 7.0 meters per second with 69 millisecond dwell time, and a depth of engagement of 2.39 mm. Length and width of 10 apertures were measured and averaged and the aspect ratio calculated. Results are shown in the table below and demonstrate that the aspect ratio of samples apertured with teeth oriented at an angle relatíve to the rnachine direction ofthe film have a lower aspect ratio than those where the teeth and the rnachine direction ofthe film were aligned in the same direction. Photomicrographs ofthe apertures formed in samples 3 through 7 are shown in FIG. 16a through 16e, respectively.

EP 2 596 923 Β1

<td colspan="6"> Table 2</td>

<td> Sample</td><td> Tooth Orientation Angle °</td><td> Average Aperture Length (mm)</td><td> Average Aperture Width (mm)</td><td> Average Aperture Aspect Ratio</td><td> FIG.</td>

<td> 3</td><td> 0</td><td> 1.63</td><td> 0.36</td><td> 4.51</td><td> 16a</td>

<td> 4</td><td> 30</td><td> 1.68</td><td> 0.47</td><td> 3.67</td><td> 16b</td>

<td> 5</td><td> 45</td><td> 1.24</td><td> 0.63</td><td> 2.04</td><td> 16c</td>

<td> 6</td><td> 60</td><td> 1.69</td><td> 0.48</td><td> 3.68</td><td> 16d</td>

<td> 7</td><td> 90</td><td> 1.56</td><td> 0.57</td><td> 2.83</td><td> 16e</td>

[0079] According to the invention, priorto forming apertures in the film, the molecularorientation is modified by plastically deforming the film to optimize the relatíve angle between the orientation ofthe teeth and the molecularorientation ofthe film. For ínstance, the molecular orientation of an MD oriented film is modified by plastically deforming the web in the CD resulting in a higher proportion of long chain molecules arranged in the CD. Preferably, the MD oriented film can be plastically deformed such that the predominant molecular orientation is changed from the MD to the CD. The modified web can then pass through the nip formed by MD oriented teeth producing óval shaped apertures having reduced aspect ratios.

[0080] In order to modify the molecular orientation of the precursor web, the web can be stretched or prestrained to plastically deform the web prior to passing through the forming apparátus 100 shown in FIG. 1. In one embodiment, the precursor web can be stretched to plastically deform the web by incremental stretching. As used herein, the term, incremental stretching, alsó referred to as ring rolling, is a process in which a web is supported at closely spaced apart locations and then the unsupported segments ofthe web between these closely spaced apart locations are stretched. This can be accomplished by passing the web through a nip formed between a pair of meshing corrugated rolls, which have an axis of rotation perpendicular to the direction ofweb travel. Incremental stretching rolls designed for machine direction and cross direction stretching are described in U.S. Pat. No. 4,223,059.

[0081] FIG. 17 is an enlarged, fragmentary, cross-sectional view showing the interengagement of teeth 252 and grooves 254 of respective opposing activation rolls in a nip which incrementally stretch a web 234 of matéria! therebetween. As shown, a portion ofa web 234, which can be nonwoven web, is received between the interengaged teeth and grooves. The interengagement ofthe teeth and grooves causes laterally spaced portions ofweb 234 to be pressed by teeth 252 intő opposed grooves 254. In the course of passing between activation rolls, the forces of teeth 252 pressing web 234 intő opposed grooves 254 impose within web 234 tensile stresses that act in the machine or cross machine direction depending on the orientation ofthe teeth and grooves on the rolls. The tensile stresses can cause intermediate web sections 258 that lie between and that span the spaces between the tips of adjacent teeth 252 to stretch or extend in a machine or cross machine direction, which can result in a localized reduction of the web thickness at each of intermediate web sections 258. For nonwoven webs, the stretching can cause fiber reorientation, a reduction in basis weight, and controlled fiber destruction in the intermediate web sections 258.

[0082] Although the portions ofweb 234 that lie between the adjacent teeth are locally stretched, the portions ofthe web that are in contact with the tips ofthe teeth may nőt undergo a similar degree of extension. Because ofthe frictional forces that exist between the surfaces at the rounded outer ends of teeth 252 and the adjacent areas 260 of web 234 that are in contact with the tooth surfaces at the outer ends of the teeth, sliding movement of those portions of the web surfaces relatíve to the tooth surfaces at the outer ends of the teeth is minimized. Consequently, in somé cases, the properties of the web 234 at those areas of the web that are in contact with the surfaces of the tooth tips change only slightly, as compared with the change in web properties that occur at intermediate web sections 258.

[0083] Somé materials including polypropylenes, polyethylenes and polyesters are unable to with stand the high rate ofstrain involved with incremental stretching in commercial production. Such materials can be incrementally stretched at a low rate ofstrain according to the process apparátus described in U.S. Published Application No. 2008/0224351 A1. The publication deseribes a method and apparátus which uses activation members for incrementally stretching a web at a relatively low strain rate. The activation members include an activation beit and a single activation mernber wherein the activation beit and single activation mernber comprise a plurality of teeth and grooves that complement and engage one another at a depth of engagement in a deformation zone. The depth of engagement is capable of increasing linearly over the deformation zone. In exemplary embodiments the deformation zone can be controlled to increase linearly over at least a portion ofthe deformation zone such that a web interposed between the activation beit and the single activation mernber in the deformation zone is incrementally stretched at a low rate ofstrain.

[0084] Another type of stretching apparátus useful in the present invention is a tenter. Tenters have been used for

EP 2 596 923 Β1 transverse direction stretching in film stretching processes. A tenter apparátus has grips or clippers that grasp the film along the opposing edges of the film. The stretching occurs by divergence ofthe grips or clippers on opposing edges relatíve to the direction of longitudinal movement. Such apparátus is described in U.S. Pat. No. 3,816,584.

[0085] Other methods for plastically deforming the web include hydroforming and vacuum forming.

[0086] Subsequent to stretching, the web continues in the machine direction to nip 116 comprising a pair of counterrotating, intermeshing rolls 102 and 104. The pair of intermeshing rolls 102 and 104 operates toform apertures in web

1. Intermeshing rolls 102 and 104 are more clearly shown in FIG. 2.

EXAMPLE 3 [0087] Film samples were tested for shrinkage according to ASTM method D2732-03. Square samples (4 inches on each side) were cut from 100 mesh film, immersed in 100 °C glycerol for 30 seconds, then removed and dimensions re-measured. Five specimens were tested for each matéria! and the results averaged. Without any pre-straining, the 100 mesh film sample exhibited shrinkage in the machine direction bút nőt in the cross direction, indicating that the matéria! is primarily oriented in the machine direction. The film was prestrained by incrementally stretching the web in the cross direction. After incremental stretching, the 100 mesh samples exhibited additional shrinkage in the cross direction, indicating that molecular orientation had been introduced in the cross direction as well. The data in Table 1 demonstrates that the magnitude of the shrinkage (and therefore molecular orientation) in the cross direction increases with depth of engagement employed during the ring-rolling process.

<td colspan="3"> Table 3</td>

<td> Film</td><td> Average MD measurement after heat treatment</td><td> Average CD measurement after heat treatment</td>

<td> 100 mesh</td><td> 3.86</td><td> 4.13</td>

<td> 100 mesh ring-rolled at0,127 cm (0.050 inch) depth of engagement</td><td> 3.75</td><td> 3.69</td>

<td> 100 mesh ring-rolled at 0,1778 cm (0.070 inch) depth of engagement</td><td> 3.64</td><td> 3.13</td>

EXAMPLE 4 [0088] A 100 mesh film was ring rolled prior to aperturing to illustrate the effects that prestraining the web has on apertures. 100 mesh film was apertured using 0.050 inch pitch intermeshing rolls online at a speed of 1300 feet per minute. Data shown below illustrates that ring-rolling ofthe films prior to aperturing leads to a decrease in the aspect ratio ofthe apertures, an increase in the size ofthe apertures and increase in the air permeability ofthe films. Photomicrographs of the apertures formed in samples 8 through 11 are shown in FIGS. 18a through 18d, respectively.

<td colspan="5"> Table 4</td>

<td> Figures</td><td> FIG 18a</td><td> FIG 18b</td><td> FIG 18c</td><td> FIG 18d</td>

<td> Sample</td><td> 8</td><td> 9</td><td> 10</td><td> 11</td>

<td> Ring-rolled?</td><td> no</td><td> yes</td><td> No</td><td> Yes</td>

<td> Ring-roll Pitch (inches)</td><td> —</td><td> 0,1524 cm (0.060 inch)</td><td> —</td><td> 0,1016 cm (0.040 inch)</td>

<td> Ring-roll Depth of Engagement</td><td> —</td><td> 0,127 cm (0.050 inch)</td><td> —</td><td> 0,114 cm (0.045 inch)</td>

<td> Forming apparátus Temp (°C)</td><td> 105 °C</td><td> 105 °C</td><td> 94 °C</td><td> 94 °C</td>

<td> Average Aperture Length (mm)</td><td> 2.11</td><td> 2.24</td><td> 2.06</td><td> 2.06</td>

<td> Average Aperture Width (mm)</td><td> 0.33</td><td> 0.54</td><td> 0.37</td><td> 0.55</td>

<td> Average Aperture Aspect Ratio</td><td> 6.5</td><td> 4.2</td><td> 5.6</td><td> 3.8</td>

<td> Average Aperture Size (mm²)</td><td> 0.8</td><td> 0.9</td><td> 0.7</td><td> 0.8</td>

EP 2 596 923 Β1 (continued)

<td colspan="5"> Table 4</td>

<td> Figures</td><td> FIG 18a</td><td> FIG 18b</td><td> FIG 18c</td><td> FIG 18d</td>

<td> Air Permeability 0,028 m³ per minute (cubic feet per minute)</td><td> 347</td><td> 572</td><td> 337</td><td> 517</td>

EXAMPLE 5 [0089] A fiat film was apertured with and without pre-stretching the film. A fiat film sample (TS3 Fiat film obtained from Tredegar Film Products, Terra Haute, IN) was apertured using 0.050 inch pitch intermeshing plates on the high speed research press. The temperature ofthe aperture forming plate was set at 100 °C and the temperature ofthe mating ringroll plate was set at 22 °C. Process conditions were set up to mimic a web speed of 3.125 meters per second at a depth of engagement of 2.6 mm. The resultant film (Sample 12) had apertures that are barely open and look like slits, with an aspect ratio of 20. Another sample of the same film was stretched by hand 50% in the cross direction prior to aperturing under the same conditions on the high speed research press. The resultant film (Sample 13) had open apertures with an aspect ratio of 3.4. Photomicrographs of the apertures formed in samples 12 and 13 are shown in FIGS. 19a and 19b, respectively.

<td colspan="5"> Table 5</td>

<td> Sample</td><td> Average Aperture Length (mm)</td><td> Average Aperture Width (mm)</td><td> Average Aperture Aspect Ratio</td><td> FIG.</td>

<td> 12</td><td> 2.1</td><td> 0.1</td><td> 20</td><td> 19a</td>

<td> 13</td><td> 1.7</td><td> 0.5</td><td> 3.4</td><td> 19b</td>

[0090] The precursor web can be prestrained in zones forming a web having strained and unstrained regions which is subsequently apertured resulting in different aperture sizes in the strained and unstrained zones. The strained and unstrained regions can be continuous or discontinuous and can run in both MD and the CD.

EXAMPLE 6 [0091] A 100 mesh film was incrementally stretched in zones to prior to aperturing to form zones of apertures where each zone had different aperture sizes. A sample of 100 mesh film was passed through a 0.040 inch pitch ring-roll with a width of 3 inches so that only the center portion was activated. Depth of engagement on the ring-roll was 0.045 inches. This film was then apertured using 0.050 inch pitch forming apparátus at 0.045 inch depth of engagement and 1300 feet per minute line speed. The temperature ofthe toothed roll was 94 °C and the temperature ofthe mating roll was 99 °C. The resultant apertured film had a Central zone with large apertures and side zones with smaller apertures.

Laminate [0092] Although apertured web 1 is disclosed in the illustrated embodiments as a single layer web made from a single layer precursor web 20, it is nőt necessary that it be so. For example, a laminate or composite precursor web 20 having two or more layers or plies can be used. In generál, the above description for apertured web 1 holds, recognizing that a web 1 formed from a laminate precursor web could be comprised of volcano like structures 8 wherein the sidewalls 9 comprise one or more ofthe precursor web materials. For example, if one ofthe materials ofa composite precursor web has very low extensibility, teeth 110 may punch more or less cleanly through, such that it does nőt contribute matéria! tothe volcano like structure sidewalls 9. Therefore, athree-dimensional web made from a compositeor laminate precursor web 20 may comprise volcano like side walls 9 on apertures 6 that comprise matéria! from less than all the precursor web materials.

[0093] FIGS. 20A-20C show schematically various configurations of two layer composite webs 1 having a first surface 12 and a second surface 14, wherein extending from the second surface 12 are volcano-shaped structures 8. In generál, two precursor webs designated as 20A and 20B can each be either a polymer film or a nonwoven web and processed together in layered relationship by the apparátus 150 or 200 as described above. Depending on the properties of each, such as ductility and extensibility, the result can be that either of precursor webs 20A or 20B can extend to form a threedimensional volcano-like structure 8 as shown in FIGS. 19A and 19C. The other of precursor web 20Aor 20B can simply

EP 2 596 923 Β1 be punched through to form a two-dimensional aperture, thereby nőt forming any substantially three-dimensional structure. However, as shown in FIG. 19B, both of precursor webs 20A or 20B can extend out of pláne to form a threedimensional volcano-like structure 8.

[0094] Multilayerapertured webs 1 made from composite laminate precursor webs 20 can have significant advantages over single layer apertured webs 1. For example, an aperture 6 from a multilayer apertured web 1 using two precursor webs, 20A and 20B, can comprise fibers (in the case of nonwoven webs) or stretched film (in the case of film webs) in a nested relationship that locks the two precursor webs together. One advantage ofthe locking configuration is that, while adhesives or thermal bonding may be present, the nesting allows forming a laminate web without the use or need of adhesives or additiönai thermal bonding between the layers. In other embodiments, multilayer webs can be chosen such that the fibers in a nonwoven web layer have greater extensibility than an adjacent film layer. Such webs can produce apertures 6 by pushing fibers from a nonwoven layer up and through an upper film layerwhich contributes little or no matéria! to volcano-shaped structure 8 sidewalls 9.

[0095] In a multilayer apertured web 1 each precursor web can have different matéria! properties, thereby providing apertured web 1 with beneficial properties. For example, apertured web 1 comprising two (or more) precursor webs, e.g., first and second precursor webs 20A and 20B can have beneficial fluid handling properties for use as a topsheet on a disposable absorbent artiele. For superior fluid handling on a disposable absorbent artiele, for example, second precursor web 20B can form an upper film layer (i.e., a body-contacting surface when used as a topsheet on a disposable absorbent artiele) and be comprised of relatively hydrophobic polymer. First precursor web 20A can be a nonwoven fibrous web and form a lower layer (i.e., disposed between the topsheet and an absorbent core when used on a disposable absorbent artiele) comprised of relatively hydrophilic fibers. Fluid deposited upon the upper, relatively hydrophobic layer can be quickly transported to the lower, relatively hydrophilic, layer. For somé applications of disposable absorbent articles, the relatíve hydrophobicity of the layers could be reversed, or otherwise modified. In generál, the matéria! properties ofthe various layers of apertured web 1 can be changed or modified by means known in the art for optimizing the fluid handling properties of apertured web 1.

[0096] Adistinct benefit ofthe apparátus 150 or200 as described above forforming apertured webs for use in disposable absorbent articles is the ability to adapt and position the apparátus 150 or200 as a unit operation in an existing proeess for making such articles. For example, apertured web 1 can be a topsheet in an absorbent artiele such as a sanitary napkin. Rather than make the apertured web off line, perhaps at a geographically remote location, apertured web 1 can be made on line by putting forming apparátus 150 in line with the supply of topsheet matéria! on a production line for making sanitary napkins. Doing so provides several distinct advantages. First, having forming apparátus 150 making apertures in the topsheet directly on the sanitary napkin production line eliminates the need to purchase apertured webs, which can be costly when made by traditional processes, such as vacuum forming, or hydroforming. Second, forming apertures on the sanitary napkin production line minimizes the amount of compression and flattening that three-dimensional volcano-shaped regions are subject to. For example, when three-dimensional apertured formed film webs are produced and shipped on rolls, a significant amount of compression, as well as permanent compression set, of the formed film apertures takes piacé. Such compression is detrimental to the operation of the web as a fluid pervious topsheet. Third, toothed roll 104 can be configured such that toothed regions are made in predetermined patterns, so that the apertured portion of an apertured topsheet is formed in a predetermined pattern. For example, a topsheet can be made on line in which the apertures are only disposed in the middle portion ofa sanitary napkin. Likewise, apertures can be formed such that apertured regions are registered with other visible components, including channels, indicia, color signals, and the like.

[0097] While particuíar embodiments ofthe 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 ofthe invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.