KR20140135843A - Apparatus and process for aperturing and stretching a web - Google Patents

Abstract

An apparatus and process for opening and elongating a web are disclosed. In one embodiment, a method includes feeding a web into a nip formed between at least a pair of interdigitated rolls. The first roll is a raised ridge rotary knife opening forming roll, the second roll is a ring roll; Both rolls include ridges and grooves. The first roll includes a plurality of spaced teeth extending outwardly from the upper surface of the ridge, the teeth having a tip, the upper surface of the ridge being disposed between the tooth tip and the bottom surface of the groove. These devices and processes enable a web to be formed that includes openings having a larger open area than previously achievable with conventional processes and devices.

Description

[0001] APPARATUS AND PROCESS FOR APERTURE AND STRETCHING A WEB [0002]

The present invention relates to an apertured web material, and to an apparatus and method for opening and elongating a web to produce such a material.

Various methods and apparatus for forming, deforming and / or stretching webs are disclosed in the patent literature. Methods of forming apertures, such as rotary knife aperturing, require that the openings have closely spaced openings and that these openings produce webs having a desired width in the cross-machine direction ("CD") it's difficult. In order to make the rows of apertures closely spaced from each other, activation teeth with a very small depression angle may be provided. This approach, however, poses a problem because of the high coupling depth (interference of the working tooth roll with the matching ring roll), as well as the creation of openings that do not have a sufficient opening width in the CD. The resulting apertures are often elongated in the machine direction - leading to a slit-like appearance that causes tear during use, a low open area, and potential stress concentration. Creating slit-shaped, low-open-area openings is particularly problematic when more tough and tear-resistant webs are used. Although rounded or tapered hot-pin aperturing is common, it has the disadvantage of requiring higher registration accuracy for the registration roll, which typically results in a larger opening spacing do. Rounded or tapered hot-pin opening formation is typically performed at a lower linear velocity.

Although it is possible to stretch the apertured web by post ring-rolling, it can produce alternating rows of openings because the openings can not be lined up in the subsequent ring roll stretching process. Due to the variable spreading of the substrate it is difficult to align the features in the cross direction in a subsequent process. Post ring-rolling can also significantly weaken the web, making it easier to tear.

It would be desirable to have discrete, closely spaced openings and to create webs that have larger CD widths than those previously available. There is a need for an apertured web that is stronger in the width direction and does not readily tear in the width direction. There is a need for a method of creating an apertured web having a larger, wider, more open aperture. There is also a need for a device that will allow the web to be apertured so as to have an opening with a larger width, which is preferred in the width direction.

There are many known processes for producing webs having ridges and grooves, such as ring rolling. There are also many known processes for creating webs with openings, for example hot pin opening formation. However, it is difficult to create a corrugated web with alternating ridges and grooves that conform to certain opening patterns. There is a process for forming fine-apertures followed by ring-rolling; This creates a wrinkled flattened web. Webs (flat strips) having ridges and grooves may be formed on the patterned belt by air-jetting or water jetting. However, air-jetting or water jetting is a much slower process than the invention described herein and requires more energy. In addition, the ridges are not hollow and can hold more fluid.

It is desirable to create a web having alternating ridges and grooves and having openings disposed in particular locations within the web, e.g., in the grooves or ridges. There is a need for an apertured web that includes a conformed wrinkle pattern.

These are all objects of the invention; The embodiments described herein may achieve various combinations of these purposes. Certain embodiments may, but need not necessarily, be capable of practicing all of the objects.

The present invention relates to apertured- and often corrugated-web materials, and apparatus and methods for forming openings in webs to produce such materials. Such materials include absorbent articles such as topsheet, backsheet, acquisition layer, liquid handling layer and absorbent core, packaging (e.g., flow wrap, shrink wrap, and polybag) ), Wipes, cosmetic tissue, toilet paper, paper towels, and the like. There are many non-limiting embodiments of the present invention.

The present invention relates to an apparatus comprising two interlocking forming structures forming a nip therebetween, the apparatus being a first forming structure, wherein the first forming structure comprises a plurality of A first ridge and a first groove, the first ridges having a top surface, the first grooves having a bottom surface; And a plurality of spaced teeth extending outwardly from an upper surface of the first ridges, each tooth forming an opening, the upper surface of the first ridge being between the tips of the teeth and the bottom surface of the first grooves Said first forming structure comprising: a first forming structure; And a second forming structure including a plurality of successive second ridges and second grooves.

The present invention also relates to an apparatus comprising two intermeshing counter-rotating rolls defining a nip therebetween, said apparatus comprising a first roll of generally cylindrical shape having a surface, a circumference and an axis, The first roll having a plurality of circumferential first ridges and circumferential first grooves on the surface of the roll, the first ridges having a top surface and the first grooves having a bottom surface; And a plurality of spaced teeth extending outwardly from an upper surface of the first ridges, each tooth being tapered from an upper surface to a tip, the upper surface of the first ridge being spaced from the tips of the teeth and a bottom surface The first roll being positioned between the first roll and the second roll; And a generally cylindrical second roll comprising a plurality of successive circumferential second ridges and a second groove.

The present invention also relates to a method for deforming a web using an apparatus, comprising the steps of feeding a precursor web into a nip formed between two interdigitated rolls, a) a first roll of generally cylindrical shape having a surface, a circumference and an axis, said first roll comprising a plurality of first ridges and a second groove extending around the circumference of the roll on the surface of the roll, Said first grooves having a bottom surface; And a plurality of spaced teeth extending outwardly from an upper surface of the first ridges, the teeth having tips, the upper surface of the first ridges being disposed between the tips of the teeth and a bottom surface of the first grooves, The first roll; And b) a generally cylindrical second roll comprising a plurality of continuous, circumferential ridges and grooves, the second ridges having an upper surface and the second grooves having a bottom surface; The upper portion of at least a portion of the ridges on the first roll extending inwardly toward the axis of the second roll at a depth past the top of at least a portion of the second ridges on the second roll when the web is fed into the nip, Wherein the web is (i) formed by the teeth of the plurality of spaced apart first positions to form a plurality of spaced apart openings; (ii) are stretched in the width direction by the intermeshing rolls.

The accompanying drawings are included to provide a further understanding of the invention. The drawings illustrate the invention described herein and, together with the description, serve to explain the principles of the claimed invention.
Figure 1 is a perspective view of a pair of prior art ring rolls for deforming the web.
Figure 2a is a perspective view of a prior art roll pair-rotating knife opening forming (or "RKA") roll and ring roll for forming an opening in a web.
Figure 2b is a side view of a pair of prior art rolls shown in Figure 2a.
Figure 2c is an enlarged side view of the nip between the rolls shown in Figure 2a.
Figure 2D is a plan view of an exemplary prior art web that may be formed using the roll shown in Figure 2A.
Figure 3a is a perspective view of a pair of rolls used in the apparatus and process described herein wherein one roll is a staggered "raised ridge" RKA roll and the other roll is a ring roll.
Figure 3b is an enlarged side view of the nip between the rolls shown in Figure 3a.
4A is a perspective view of a portion of the surface of an exemplary raised ridge RKA roll;
Figure 4b is a perspective view of a portion of the surface of an exemplary ring roll;
4C is a perspective view of a portion of the surface of an exemplary raised Ridge SELF roll;
5A is a perspective view of a portion of the surface of another exemplary raised ridge RKA roll;
Figure 5b is a side view of the tooth arrangement shown in Figure 5a.
Figure 5c is an end view of the tooth arrangement shown in Figure 5a;
FIG. 5D is a plan view of the tooth arrangement shown in FIG. 5A. FIG.
FIG. 5E is a cross-sectional view taken along the line DD of the tooth arrangement shown in FIG. 5B; FIG.
FIG. 5F is a cross-sectional view taken along line EE of the tooth arrangement shown in FIG. 5B. FIG.
Figure 6a is a front view of a first exemplary set of teeth, the teeth being tapered and truncated.
Figure 6b is a front view of a second exemplary set of teeth, the teeth being tapered and semi-truncated.
Figure 6c is a front view of a second exemplary set of teeth, the teeth of which are tapered and non-truncated.
Figure 7 is a schematic view of an end facet angle y and a tooth pattern that the ridge finish can be achieved by a single spiral machining step.
8 is an enlarged side view of a portion of the surface of an alternate raised ridge RKA roll;
Figure 9a is a plan view of an example of a web that may be formed using a variation of the roll of Figure 3a.
Figure 9b is an enlarged view of one of the openings shown in Figure 9a.
Figure 10 is a side view of another embodiment of an apparatus for forming apertures in a web in which the three rolls are in a planetary arrangement.
11 is a top view of a 25 gsm PE film web (the film is stretched / planarized to show high and low basis weight areas).
12 is a top view of a 60 gsm PP nonwoven web (the nonwoven fabric is stretched / planarized to exhibit high and low basis weight areas).
Figure 13 is a cross-sectional view of the web shown in Figure 12;
14 is a side perspective view of another nonwoven web.
15 is a top perspective view of a nonwoven web.
16 is a cross-sectional view of a film web;
17, 18A and 18B are plan views of the apertured film web described in Example 1;
19A is a top perspective view of an apertured nonwoven web as described in Example 2;
Figure 19b is a bottom perspective view of the web of Figure 19a.

The following text describes a broad description of many different embodiments of the present invention. The description is to be construed as illustrative only, and not all possible embodiments are described, since it would be impractical, if not impossible, to describe every possible embodiment. It is also to be understood that any feature, characteristic, element, composition, element, product, step or method described herein may be deleted or replaced with any other feature, characteristic, element, composition, Steps or methods described herein may be wholly or partly combined or substituted. Many alternative embodiments may be implemented using techniques developed after the present technology or the filing date of the present patent, and still fall within the scope of the claims. All publications and patents cited herein are incorporated herein by reference.

It is also to be understood that the term "as used herein, the term " ______ " is hereby defined to mean ", or a similar sentence unless the context clearly dictates otherwise herein. Is not intended to limit the meaning either explicitly or implicitly, beyond its ordinary or ordinary meaning, and such term is intended to encompass any and all claims, words, It should not be construed as limiting the scope. No language is intended as such, unless stated to the essentials of the present invention. To the extent that any term listed in the appended claims of this patent is referred to in this patent in a manner consistent with a single meaning, it is for the sake of clarity only that the reader is not confused and that the terms of such claims are implicit Or otherwise limited to a single meaning thereof. Finally, unless the elements of the claims are defined by listing the functions without the word "means" and without listing any structure, the scope of any element of the claims is limited to 35 U.S.C. It is not intended to be interpreted on the basis of the application of § 112, sixth paragraph.

The present invention enables an apertured web that is stronger in the width direction and does not readily tear in the width direction. A process for making an apertured web having discrete, closely spaced openings with a greater width desired in the width direction is described. The process may also produce a structure having alternate ridges and grooves and wherein the apertures are received within the grooves. Apparatus is also described which allows the web to be apertured with the desired discrete, closely spaced, and wider width openings in the width direction.

As used herein, the term "absorbent article " includes disposable articles such as sanitary napkins, pantiliners, tampons, interlabial devices, wound dressings, diapers, adult incontinence articles, wipes, In addition, the absorbent member produced by the process and apparatus described herein may be useful in other webs, such as scrubbers, dry-mop pads (e.g., SWIFFER ' s pads) . At least some of these absorbent articles are intended to absorb body fluids such as menses or blood, vaginal discharge, urine, and feces. The wipe may be used to absorb body fluids, or may be used for other purposes, such as to clean the surface. The various absorbent articles described above will typically include a liquid pervious topsheet, a liquid impermeable backsheet joined to the topsheet, and an absorbent core between the topsheet and the backsheet.

As used herein, the term "absorbent member " typically refers to components of an absorbent article that provide one or more liquid handling functionalities such as liquid acquisition, liquid distribution, liquid transport, liquid storage, and the like. When the absorbent member comprises an absorbent core component, the absorbent member may comprise only a portion of the entire absorbent core or absorbent core.

As used herein, the term "opening" refers to a hole. The opening can be neatly punched through the web ("two-dimensional" opening) so that the material surrounding the opening lies within the same plane as the web before formation of the opening, or at least a portion of the material surrounding the opening is pushed out of the plane of the web And the hole formed. In the latter case, the opening may be similar to a "three-dimensional" opening. The three-dimensional opening generally maintains a larger opening area under an applied load. As used herein, the term "apertured" refers to a web comprising a plurality of openings.

As used herein, the term "component" of an absorbent article refers to absorbent articles such as topsheet, acquisition layer, liquid handling layer, layers of absorbent core or absorbent core, backsheet, and barrier, Quot; refers to the individual components of the article.

As used herein, the term " corrugated "or" corrugation "refers to a three dimensional web topography comprising a plurality of generally parallel alternating ridges and grooves, wherein the ridges and grooves Which is drawn in the horizontal direction through the X-axis. The ridges and grooves can have the same wave shape on either side of the shaft, or can be offset to one side.

As used herein, the terms "width direction", "cross direction", or "CD" means a path perpendicular to the machine direction in the plane of the web.

As used herein, the term "deformable material" is a material that can change its shape or density in response to an applied stress or strain.

As used herein, the term "depth of engagement" ("DOE") means the degree of engagement between two rolls. The distance is measured from the tooth on the first roll or the outermost tip of the ridge to the tooth on the second roll or the outermost tip of the ridge. As used herein, the term "interlocking" or "intermeshing" means that a tooth / ridge on one of the rolls extends toward the surface of another roll and at least a portion of the tooth / Refers to an arrangement when having a portion extending between and below virtual planes drawn through the tip.

As used herein, the term "discrete" means separate or unconnected. When the term "discretized" is used for a tooth on a raised ridge roll, it means that the distal (or radially outermost) end of the tooth is separate or unconnected in all directions including machine and width directions Even if the base of the inlet can be formed in the same surface of the roll). For example, the ridge on the ring roll is not considered to be discrete.

As used herein, the term " disposable "describes absorbent articles and other articles that are not intended to be washed or otherwise restored or reused as absorbent articles or articles (i.e. they are intended to be discarded after use, Or composted or otherwise treated in an environmentally friendly manner).

As used herein, the term "hollow" describes ridges and grooves present in webs produced by the apparatus and processes described herein; The ridges and grooves include open spaces in which no web material is present. For example, the web includes an X-axis drawn horizontally through the ridges, grooves and cross-sections of the web; The region above the X axis, but below the top of the ridge, is either hollow or contains a hollow region. Similarly, the region below the X-axis, but on the bottom of the groove, is hollow or includes a hollow region.

As used herein, the term "machine direction" or "MD" means a path followed by a material such as a web through the manufacturing process.

As used herein, the term "macroscopic" refers to a structural feature that is easily visible and clearly distinguishable to a person with 20/20 vision when the vertical distance between the viewer ' s eye and the web is about 30 cm Or < / RTI > Conversely, as used herein, the term "micro" refers to such features that are not readily visible and clearly indistinguishable under these conditions.

The term "ring roll" or "ring rolling ", as used herein, refers to a continuous (or continuous) arrangement of interlocking ridges (or protrusions) and grooves (or recesses) Refers to a process using such a deformable member comprising a counter-rotating roll, an interlocking belt, or an interlocking plate comprising at least a portion of the ridges and grooves. Unless otherwise stated, the ring rolls do not singly open the web. In the case of ring rolling, the deformable member may be arranged to stretch the web in the direction of the width, in the machine direction, or in a predetermined angle / spiral direction to the CD or MD according to the orientation of the ridges and grooves. It should be understood that the examples described herein with respect to one direction enable directions that are not described.

As used herein, the term "rotatable knife opening formation" (RKA) refers to processes and apparatus that use interdigitated deformable members or rolls, wherein one or more rolls comprise a plurality of teeth. Not only can the teeth be cut through the web, but the web can also be deformed to create an apertured web, or in some cases, to create a three-dimensionally apertured web as disclosed in U. S. Patent Nos. 2005 / 0064136A1 and 2006 / 0087053A1 have.

The term " SELF "or" SELF " refers to Procter & Gamble technology, where SELF stands for Structural Elastic Like Film. Processes, apparatuses and patterns produced through SELF are described in U.S. Patent Nos. 5,518,801; 5,691,035; 5,723,087; 5,891,544; 5,916,663; 6,027,483; And 7,527,615 B2. A tuft (in the case of a nonwoven) or a tent (in the case of a film), which originally was developed using a tooth geometry to deform the polymer film without creating an opening, but with openings at the leading and trailing ends, Other geometric shapes have been developed that are even more helpful in forming. A process using SELF'ing to form tufts with openings in nonwoven webs is disclosed in U.S. Patent No. 7,682,686 B2.

As used herein, the term "tooth" refers to any element on the surface of a roll that can form an opening in the web.

I. Opened web material

Although the term "apertured web material" is used herein, the purpose is to create a component, such as an absorbent member (or non-absorbent member) for the absorbent article from such apertured web material. In this case, the apertured web material will be cut into discrete components for the absorbent article (e.g., topsheet, backsheet, acquisition layer, absorbent core). In the case of webs used in absorbent articles, such new structures may include those that provide improved properties (e.g., improved softness, fluid handling, or other characteristics) to a predetermined portion of the web. These apertured webs can be cut to form various other components, such as wipes, cosmetic tissue, toilet paper, paper towels, etc., for packaging (e.g., flow wraps, shrink wrap and poly bags).

A discrete, closely spaced opening with a larger width in the CD direction can be provided in the web and components formed therefrom are not possible to produce with current methods and tools. The new openings have a larger opening area and a lower aspect ratio (aperture length: less than 10 mm) to produce increased web strength, as compared to an equivalent open area opening achievable through the prior art (in the case of films) Aperture width).

In addition, the webs created with this new technology are unique and have a more textured appearance. The textured web may include alternating ridges and grooves, wherein the openings are intentionally included in the grooves. In the case of an apertured web used for an absorbent article, the web can provide better fluid acquisition, breathability, or separation from the body, thus promoting a drier, cleaner feel. For example, in sanitary napkins, openings located in the grooves help to send and deliver fluid from the topsheet to the lower absorbent member. The apertures not only provide these advantages, but any wrinkles present in the final web can additionally support these advantages. For example, the wrinkles provide at least partial non-contact with the body, which improves breathability, creates a drier feel, and may result in wet / contaminated surfaces that can irritate the skin or feel uncomfortable To promote less contact. In the case of a sanitary napkin, the wrinkle can send fluid in a longitudinal direction along the sanitary napkin and can maintain fluid away from the side edges of the sanitary napkin.

The web (or "precursor web") to be apertured may comprise any suitable deformable material, such as a woven fabric, a nonwoven, a film, a flat film, a micro-textured film, a combination of any of the foregoing materials or a laminate . As used herein, the term "nonwoven web" refers to fibers that have a structure of individual fibers or yarns interposed therebetween, but typically have no repeating pattern, such as in woven or knitted fabrics that do not have randomly oriented fibers Quot; web. &Quot; The nonwoven web may or may not include a thermal interface. It may include paper substrates such as tissue, dry wrap, liner board, filter paper, and combinations thereof. The nonwoven webs or fabrics may be fabricated by any process known in the art, such as, for example, meltblowing, spunbonding, hydroentangling, airlaid, wetlaid, And bonded carded web processes including carded thermal bonding. ≪ Desc / Clms Page number 2 > Depending on the forming process, the nonwoven web may or may not include a thermal interface. The film material may be a single layer, multi-layer, embossed, or micro-textured. Woven fabrics, nonwoven fabrics, films, assemblies or laminates can be made from any suitable material including, but not limited to, natural materials, synthetic materials, and combinations thereof. Suitable natural materials include, but are not limited to, cellulose, cotton linter, bagasse, wool fibers, silk fibers, and the like. In some embodiments, the web material may be substantially free of cellulose and / or may exclude paper material. In another embodiment, the process described herein can be performed on a cellulose-containing precursor material. Suitable synthetic materials include, but are not limited to, rayon and polymeric materials. Suitable polymeric materials include polyethylene (PE) such as linear low density polyethylene (LLDPE), low density polyethylene (LDPE), high density polyethylene (HDPE), etc.), polyester, polyethylene terephthalate (PET), and polypropylene However, it is not limited thereto. Any of the above-described materials may include materials that are recycled after consumption. The apparatus described herein operates with a wide range of materials and low cost materials. For example, multiple layers of raw material spunbond nonwoven fabrics with different chemical and mechanical properties can be used, including two or more layers of nonwoven fabric and various fiber formulations and formulations; Or the degree of cross-mixing of the films. In addition, the device can operate directly on-line (and does not lose the loft due to roll compression / storage).

A variety of polymers can be used to create the web of interest. Possible materials are bio-derived poly (bio-PE), bio-derived polypropylene (bio-PP), bio-derived polyethylene terephthalate (bio-PET), and bio- , 5-furan dicarboxylate) (bio-PEF). These materials may be derived in part or in whole from at least one renewable resource, wherein renewable resources refer to natural resources that can be supplemented within a 100 year time frame. Renewable resources include plants, animals, fish, bacteria, fungi, and forest products, and may be naturally occurring, hybrid, or genetically engineered organisms. Natural resources such as crude oil, coal and peat that take longer than 100 years to form are not considered to be renewable resources. Other polymers derived from non-petroleum based sources include starch based polymers and cellulosic materials. Additionally, recycled resins such as crushed recycled r-HDPE, r-LLDPE, r-LDPE, r-PET, r-PEF, or r-PP may be used as 100% after consumption or may be blended with various resins have. Polymers derived from renewable resources and recycled resins may be used as such or may be blended into petroleum polymers at varying levels to control costs. Sources and methods for making polymers from non-petroleum based sources can be found in U.S. Patent Nos. 8,063,064 B1 and 2011/0319849 Al.

The present invention relates to an apertured web material and to an apparatus and process for opening and elongating a web to produce such a material that overcomes one or more disadvantages of the prior art. Elongating or growing the web is advantageous because it allows low cost through the overall basis weight reduction of the web. By elongation after opening formation in the same process step, a wider and more preferred opening is created in the web material. Here, the aperture formation and elongation are accomplished in a single unit operation in a coordinated manner so that the elongation occurs while the teeth still penetrate the material and, therefore, does not allow the aperture to collapse when elongated. The additional stretching step not only allows the opening to be wider, but also has the potential to create a web having a pleated appearance. This opening-post-elongation combination must be precisely matched. If the opening formation and elongation are separate steps as in the prior art, the opening will not coincide with the stretching ring roll and the opening will be close. Also, the webs produced by this new process are softer and more drapable (loosened and / or thinned fibers and / or films) from the kidneys. Thinner webs are generally preferred because less fluid can be retained by the web. This is important when the web is used as a topsheet for absorbent articles because there is less saturation in the topsheet.

In one non-limiting embodiment, the apertured web material comprises a web having discrete openings formed therein. The web has a first surface and a second surface opposite the first surface. The web includes a substantially non-apertured formed area or land surrounding a plurality of discrete openings.

The opening is filled in a relatively small area. For example, the center-to-center spacing in any direction between the openings may be about 20 mm, 10 mm, 5 mm, 3 mm, 2 mm, 1 mm, or 0.5 mm or less. The total number of openings in the area measured by 645 mm 2 (1 square inch) may be 4, 25, 100, 250, 500, 1000, or 3000 or more. The number of openings within a square area of 25.4 mm (1 inch) represents the area of the square on the material measured as a 25.4 mm (1 inch) by 25.4 mm (1 inch) with a fine tip pen or marker and a 25.4 mm Second, third, etc. openings that lie entirely or partially on the interior and the boundary of the openings. A low magnification microscope or other magnifying tool may be used to assist in visibility of the aperture in the material when needed. The apertures can be of any suitable configuration.

The apertures can be of any suitable size. Typically, the aperture will be macroscopic. The planar area of the opening may be about 0.5 mm 2, 1 mm 2, 5 mm 2, 10 mm 2, or 15 mm 2 or more. The process described herein can also be used to create microscopic apertures having a planar area of less than 0.5 mm < 2 >.

In addition to the openings, the web may include alternating ridges and grooves, in which case the openings are located in the grooves. The ridges may extend continuously or may form discontinuous ridges in the strained regions of the web. The grooves extend continuously, wherein the openings can be spaced at regular intervals in the grooves. Note that if the web is inverted, the groove will be a ridge, the ridge will be a groove, and the opening will now be located within the ridge. The apertures can be two-dimensional or three-dimensional, depending on the process and material parameters. In the case of a three-dimensional opening, the base of the opening will extend in the opposite direction of the ridge. The sides of the ridge and the side of the groove are more oriented in the z-direction than the top of the ridge and the bottom of the groove.

In the case of films, the sides of the ridges and the sides of the grooves may be thinner and may have a lower basis weight than the bottoms of the ridges and grooves as a result of the stretching process. This creates areas of alternating higher calipers and weights and lower calipers and areas of lower basis weights wherein the areas of higher caliper and weight are located at the bottom of the ridge and at the bottom of the ridge, Is located within the sidewall between them. Alternate basis weights provide a thin / flexible area for comfort and a maintained thickness for strength.

In the case of nonwoven fabrics, the basis weight is also reduced in the stretched region to produce a web having regions of alternating higher and lower basis weights, wherein the regions of higher basis weights are located at the bottom of the ridge and at the bottom of the ridge, The areas of lower basis weight are located in the sidewalls therebetween. In the case of nonwovens, the web thickness may not decrease within the stretched area as the fibers are loosened and moved away from each other. However, the thickness of a portion of the individual fibers can decrease as a result of elongation, resulting in fiber diameters ranging from 40% to 80% of the original fiber diameter. The average fiber diameter at the top of the ridge and the average fiber diameter at the bottom of the groove may be greater than the average fiber diameter at the sidewall. With the teeth locked in the ridge and groove, the base web thickness does not change significantly. Although the web is textured, the thickness of the localized webs in the ridges and grooves does not change significantly as the ridges and grooves are deformed out of plane, so that the ridges and grooves are not filled, rather than forming hollow regions. The hollow ridges can not hold as much fluid as the filled ridges, which can provide a drying benefit when used as a topsheet in an absorbent article. As a result of stretching, the web is permanently stretched in the direction of the kidney. Suitably, the web thickness in the stretched region is 20% to 80% of the original web thickness.

II. Prior art devices for modifying web materials

The prior art approach is not suitable for creating openings with a wider dimension - in particular in a tough or tear-resistant film. Thus, in order to obtain openings in the web material with larger dimensions in the width direction than can be achieved with prior art approaches, the same process steps (i.e., in the same nip and while the aperture formation still passes through the web) It is desirable to design a process that enables opening formation and subsequent elongation. The prior art approach is also not suitable for creating webs having alternate ridges and grooves using fast-opening forming and stretching means such as those described herein, where the openings are located in the grooves.

1 shows a first prior art device 10 in which rolls 12 and 14 are referred to herein as ring rolls. The rolls 12 and 14 are supported on respective rotatable shafts having their rotation axes A arranged in a parallel relationship, as in the case of rolls in the other devices described and illustrated herein. In all of the embodiments described herein, the rolls are non-contact, axial-driven. In this embodiment, the surface of the roll has a plurality of alternating grooves 16 and ridges 18 extending around the circumference of the roll. In other embodiments, the ridges and grooves may extend parallel to the axis A of the roll. One or more such rolls may be used in various embodiments of the apparatus described herein.

In the embodiment shown in FIG. 1 and in various other embodiments described herein, the rolls are engaged or at least partially interlocked. As shown in Figure 1, the roll typically rotates in the opposite direction (i. E., The roll reversely rotates). This is also true of other embodiments described herein.

Figures 2A-2C illustrate a second prior art device 20 in which the top roll 22 is a rotary knife opening forming (or "RKA") roll and the bottom roll 24 is referred to herein as a ring roll. The apparatus includes a pair of counter-rotating, intermeshed rolls, wherein the top roll (22) includes a pyramidal tooth (30) having four or more sides, the side is substantially triangular and tapers And the bottom roll 24 includes a circumferentially extending groove 26 and a ridge 28. [ The teeth 30 are arranged in spaced circumferential rows with grooves therebetween. The teeth 30 extend from the upper roll 22 at the base, and the base of the teeth has a cross-sectional length dimension greater than the cross-sectional width dimension. Typically, the openings are formed in the web material as the teeth 30 on the RKA rolls 22 mesh with the grooves 26 on the ring roll 24. Regarding tooth height, tooth spacing, pitch, bond depth, or other process parameters, the RKA and RKA devices may be the same as those described in U.S. Patent Application Publication No. 2006/0087053 Al.

The RKA roll 22 shown in FIG. 2A includes a staggered (contrasting to standard) tooth pattern. As used herein, the term "staggered" means that adjacent values are not aligned in the column with the CD. As used herein, the term "standard" means that adjacent values are aligned in the column with the CD and thus are not staggered. The rolls 22 and 24 are aligned in the width direction so that the teeth 30 on the RKA roll 22 align with the grooves 26 on the ring roll 24, As the tooth 30 penetrates the web, the ridge on the mating ring roll 28 supports the web so that the teeth 30 can penetrate the web and at the same time form an opening in the opposite direction.

2D illustrates a top view of an exemplary prior art web 34 that may be manufactured by an apparatus such as that shown in Figs. 2A-2C. The resulting web 34 includes a land 36 surrounding the opening 38. Openings 38 formed by prior art devices such as those in Figs. 2A-2C include a length L in the machine direction and a width W in the width direction. These openings are typically slit-shaped, with a width W that is much smaller than the length L, especially for heavier and more recoverable webs.

III. Apparatus and process employing rolls having teeth extending from raised ridges to form apertures in web material

Generally, the apparatus includes two intermeshing forming structures that form a nip therebetween. The forming structure may include rollers, plates, belts, sleeves, other structures capable of imparting a texture to the web, or a combination thereof. The first forming structure includes a plurality of first ridges and a first groove on the surface of the forming structure, wherein the first ridge has an upper surface and the first groove has a bottom surface. The first forming structure may further comprise a plurality of spaced teeth extending outwardly from the upper surface of the first ridge, each tooth forming an opening, wherein the upper surface of the first ridge, And the bottom surface of the first groove. The second forming structure includes a plurality of successive second ridges and second grooves.

More specifically, the apparatus includes a single pair of anti-rotation intermeshing rolls forming a single nip (N) therebetween. Although the device will be described herein primarily for convenience as a side view of the roll, this description may be applied to a pair of rolls; Pairs of plates; A conveyor having a puck (or a small plate); belt; But not limited to, any suitable type (s) of molded member (s) including, but not limited to, The first roll and the second roll each comprise a surface (106, 108) comprising a plurality of circumferentially extending ridges and grooves. Alternatively, the ridges and grooves may extend in a direction parallel to the axis of the roll, as long as they are matched to rolls having ridges and grooves extending in the same direction. The first roll further comprises a plurality of spaced teeth, wherein the teeth extend outwardly from the upper surface of the ridge. This creates "raised ridge ". The ridge of the second roll extends to a depth past the top of at least a portion of the ridge on the first roll toward the axis of the first roll. In this manner, the initial engagement of the teeth creates an opening, and then extends in the width direction as the engagement progresses to a depth below the raised ridge. By first forming apertures in one process step and then stretching the teeth while still passing through the web, the resulting apertures are arranged in a direction transverse to the opening to be produced by the standard toothed rolls as described above and shown in Figures 2a to 2d And has a larger width.

The openings of the present invention particularly include a lower film aspect ratio (aperture length: aperture width) and a much larger open area when used with more rigid films, such as those containing high levels of LLDPE. The new tooth geometry facilitates a large open area at lower tool temperatures, allowing the formation of openings in the web that can not be apertured into a conventional tooth geometry. The new tool geometry provides the ability to open the web at lower temperatures (e.g., from 35 degrees to 70 degrees Celsius) or even at ambient temperatures rather than requiring heating of the apparatus. Also, among other things, it minimizes or reduces the costs associated with creating such tools, as opposed to conventional tools, because less metal is removed. Thus, a room temperature precursor web can be used. In one embodiment, precursor webs and intermeshed rolls are not heated. Alternatively, a full preheated web can be used. Alternatively, zoned pre-heating of the web may enable opening in some areas and enable bubbles in other areas. Preheating can be accomplished by wrapping the RKA roll (with various wrap counts possible before bonding) prior to bonding, or by wrapping the ring roll before bonding. Likewise, a heated or non-heated tool can be used. Suitably, the web is heated by wrapping the heated RKA roll at 50 to 200 degrees Celsius or 50 to 100 degrees Celsius. The RKA roll and ring roll may be driven at the same speed of the outermost surface, or there may be a speed difference between the two rolls.

The following figures illustrate non-limiting examples of specific roll arrangements and apertured web materials that may be formed thereby. These devices can utilize a single nip and can be operated at a higher processing speed and at a lower cost, in some cases, without heat, than with prior art methods for opening formation and elongation (e.g., - only two intermeshed rolls).

3A and 3B illustrate an exemplary apparatus 100 of the present invention that includes a single pair of anti-rotation intermeshing rolls 102, 104 that form a single nip N therebetween. The first (upper) roll 102 is a variation of the RKA roll shown in FIG. 2A. This particular variant will be referred to herein as a "raised Ridge RKA roll ". The second (bottom) roll 104 in the apparatus 100 shown in Figures 3A and 3B is a ring roll.

4A, first roll 102 includes a plurality of grooves 110 and ridges 120 and a plurality of staggered spaced teeth (not shown) extending outwardly from upper surface 122 of ridge 120 130). The configuration of the roll 104 is such that the top surface 122 of the ridge 120 is oriented between the tip 134 of the tooth 130 and the bottom surface 112 of the groove 110, As shown in FIG. As shown in FIG. 4B, the second roll 104 includes a plurality of grooves 140 and a ridge 150. The groove 140 has a bottom surface 142 and the ridge 150 has an upper surface 152. Here, the distance between the top surface 152 of the ridge 150 and the bottom surface 142 of the groove 140 is substantially the same around the circumference of the roll. 4C is an alternative second roll 104B in the form of a raised ridge staggered CD SELF roll. The configuration of the roll 104B is such that the top surface 122 of the ridge 120 is oriented between the tip 134 of the tooth 130 and the bottom surface 112 of the groove 110, As shown in FIG. 3A and 3B, the teeth 130 and ridges 120 of the first roll 102 extend toward the axis A of the second roll 104 and the second roll 104 To a depth past the top portion 152 of at least a portion of the ridge 150.

A suitable tooth for this process should aid in forming the opening in the web. The roll teeth can have any suitable configuration. A given tooth may have the same planar length and width dimensions (such as a tooth having a plan view in the form of a circle or square). Alternatively, the tooth may have a length greater than its width (such as a tooth with a rectangular plan) and in this case the tooth may have any suitable aspect ratio of its length to its width. A suitable configuration for teeth is a side view of a triangular shape; A side view of a square or rectangular shape; Columnar shape; A tooth having a pyramid shape; A tooth having a planar configuration including a circle, an ellipse, an hourglass shape, a star shape, a polygon, and the like; And combinations thereof. The polygonal shape includes, but is not limited to, a rectangle, a triangle, a pentagon, a hexagon, or a trapezoid. The side walls of the teeth can be tapered at an angle from the base to the tip, or they can change the angle. The teeth can be tapered from the tooth tip toward a single point as shown in Fig. 4A. The teeth can have a round, flat, or tip that forms a sharp point. Alternatively, the teeth may be tapered toward the multi-point, elongated tip as in the SELF value shown in FIG. 4C. However, the tip of the tooth should form a sharp apex with at least one of the vertical walls of the tooth (e.g., the tip of the tooth and the vertical wall on the back end as shown in Figure 4C), thereby opening or puncturing the beating web. In the case of the tooth shown in FIG. 4C, each tooth can form two openings, one at the leading edge of each tooth and one at the trailing edge.

5A-5F, the first roll 102 includes a plurality of pyramid-shaped teeth 130 that extend outwardly from the top surface 122 of the ridge 120 . 5A is a perspective view of a portion of the surface of another exemplary raised ridge RKA roll. Fig. 5B is a side view, Fig. 5C is an end view, and Fig. 5D is a plan view of the tooth arrangement shown in Fig. 5A. 5E is a cross-sectional view along the line DD of the tooth arrangement shown in FIG. 5B. FIG. 5F is a cross-sectional view taken along line EE of the tooth arrangement shown in FIG. 5B. The tooth cross-sectional area A _t shown in Fig. 5E is smaller than the tooth cross-sectional area A _tb shown in Fig. 5F. The sides (e.g., 130a-130f in FIG. 5e) are substantially triangular and taper from the tip 134 to the base 132 at an angle. The number of sides may be four (e.g., FIG. 4A), six (e.g., FIGS. 5A through 6C), or other numbers of 12 or less. The teeth 130 are arranged in spaced circumferential rows with grooves 110 therebetween. The MD tip-to-tooth spacing S _MD is 0.4 mm to 15 mm (or 3 mm to 8 mm). The CD pitch (P) is 0.4 mm to 10 mm (or 1 mm to 3 mm). A sidewall angle? On a long side (e.g., 130c, 130f) of a tooth of 3 to 15 degrees and a sidewall angle? Of 45 to 120 degrees (or 60 to 90 degrees (E.g., the angle between the side surfaces 130a, 130b or the angle between the side surfaces 130d, 130e) of the tip and trailing edge of the tooth of the tooth of the tooth of the tooth of the tooth of the teeth of the tooth. In some cases, the MD and CD tooth spacing, staggering, and end-facet subtended angle? Are selected when the teeth are formed by helical grinding.

There are different ways of finishing the portion 136 where the tooth 130 and ridge surface 122 meet, for example being cut off (Figure 6a), wherein the taper on each side is cut by a plane; Semi-truncated (FIG. 6b), wherein the taper on at least one side is cut by a arc; Or non-truncated (FIG. 6c), wherein the taper on each side is not cut in any way. The teeth 130 shown in FIG. 6A have tapered and truncated lower portions 136 from the tip 134 toward the base 132. The taper and / or frustum can be made to different degrees. The truncated taper on the teeth makes the teeth more manufacturable. In this case the, the tool as a single spiral machining step, as FIG. 7, the end carding angle (γ) and the ridge end is well known in manufacturing practices at the same time to rotate in the circumferential direction (D _C) in the axial direction of the tool Can be achieved by advancing machining. The end surface of the tooth 130 will be produced along the machining path M _P. Thus, the displacement value is generated by (T _S), the end carding included angle (γ) is 2 * Arctan (CD value pitch "P" / displacement value "T _S") with respect to the.

The top surface 122 of the ridge between the teeth 130 may be finished in a different manner. For example, surface 122 may be radiused or non-radial. The radial surface will prevent the web from tearing, especially during film formation, while the non-radial surface (e.g., surface 122 shown in Figs. 6A-6C) may be more cost effective.

The configuration of the raised ridge RKA roll 102 is such that the top surface 122 of the ridge 120 is oriented in a direction 134 relative to the axis A of the roll 102, And the bottom surface 112 of the base 110. [ The tooth height h _t is defined as the distance between the tip 134 of the tooth 130 and the bottom surface 112 of the groove 110. The tooth height h _t is from 1 mm to 12 mm, or from 2 mm to 8 mm, or from 3 mm to 6 mm. The ridge height (h _r ) is 20% or more of the tooth height, typically 20% to 95%. Cross - (d _cc) depth of cut (cross-cut depth) is defined as the distance between the upper surface 122 of the tip 134 and the ridge 120 of the value (130). In this embodiment, the distance between the tip 134 of the tooth 130 and the top surface 122 of the ridge 120 is substantially the same around the circumference of the roll. The cross-cut depth (d _cc ) depends on the amount of deformation required to form the opening. For example, the cross-cut depth (d _cc ) may be in the range of 0.2 mm to 9 mm, or 1.0 mm to 4.0 mm, or 2.0 mm to 3.5 mm. A smaller cross-cut depth (d _cc ) (at the same DOE) results in more open apertures. The coupling depth of the pair of rolls 102, 104 should be greater than the cross-cut depth (d _cc ). Suitably, the bond depth is at least 0.1 mm or 0.3 mm greater than the cross-cut depth. In the nip N, the DOE is 0.5 mm to 10 mm, or 3 mm to 7 mm, or 3 mm to 4 mm.

The ridge height h _r is defined as the distance between the top surface 122 of the ridge 120 and the bottom surface 112 of the groove 110. In some embodiments, as shown in Figures 3B and 4A, the first roll 102 includes a cross-directional width and includes a top surface 122 of the ridge 120 and a bottom surface < RTI ID = 0.0 > 112 are substantially the same across the CD width of the roll 102 and around the circumference. Alternatively, the distance between the top surface of the first ridge and the bottom surface of the second groove may vary over the CD width of the first roll or around the circumference. Various alternative embodiments of raised ridge rolls are possible. For example, the height ( _r ) of the ridges may vary between at least a portion of the teeth 168, as shown on the roll 162 in Fig. The ridge height (h _r ) depends on the amount of deformation required to form the desired opening. The top surface 166 of the at least one ridge (164) between the pair of teeth 168 is at least 10%, 20 than the height of the other ridges (164) between another pair of teeth (168) pairs (h _r2) % Or 30% greater height (h _r1 ). This roll 162 may be used in a process such as that shown in Fig. 3A instead of a raised-ridge RKA roll 102. Fig. The second roll may be a ring roll having ridges of different heights in the circumferential or axial direction.

FIG. 9A shows an apparatus as shown in FIG. 3A: an example of a web 170 that can be produced by ring rolls against an RKA raised-ridge roll with a staggered tooth pattern for the top roll 102 and a lower roll 104 / RTI > The rolls 102 and 104 are aligned in the width direction so that the teeth 130 on the first roll 102 are aligned with the grooves 140 on the second roll 104. As the teeth 130 of the first roll 102 pass through the web 170 the ridge 120 between the teeth 130 on the RKA raised ridge roll 102 is displaced from the ridge 120 on the second roll 104 150 support the web 170 so that it can stretch the web 170 in the width direction.

The web in the initial state can be considered to include relatively flat, non-apertured regions as a whole. The web 170 has a first surface 170A and a second surface 170B. When the web is fed in the machine direction into the nip N between rolls (e. G., Those shown in FIG. 3A), the web may include (i) a plurality of spaced openings 172 An opening formed by the teeth 130; (ii) the ridge 120 of the first roll 102 to stretch the opening 172 in the width direction. The result is an apertured web 170 that includes openings 172 and lands 174 that surround openings 172, as shown in the web top view of Figure 9a. The opening 172 can be pushed out of the plane of the web 160 in one direction (downward as shown in Fig. 9A), so that the opening 172 can have _a height H _a . The openings 172 are aligned with the rows of MD and CD. FIG. 9B shows an enlarged plan view of a single opening 172. FIG. The opening 172 includes _a length L _a in the machine direction and _a width W _{a in the} width direction. The aperture will have a length aspect ratio (AR) divided by a width of preferably 1 to 4, or 1.25 to 3, or 1.5 to 2.5, or 1.6 to 2.3. Opening 172 also includes a peripheral portion surrounding the individual open area (A _a) and an open area (P _a). The apertured web comprises a total open area of 5% to 25%, or 9% to 21%, or 10% to 16%, or 14% to 20% of the total web area. The apertured film has a tear strength or tensile strength (per 25.4 mm) in the width direction in the range of 1.5 N to 5 N, 2 N to 4 N, 2.5 N to 4 N, 2.5 N to 3.5 N, or 2.7 N to 3.9 N, . The apertured nonwoven fabric comprises a tensile strength in the transverse direction (per 25.4 mm) in the range of 2 N to 20 N or more. In one example, the web comprises a machine direction orientation and a width direction orientation, wherein the aperture comprises a length in machine direction and a width in the width direction, and the plurality of apertures includes a length aspect ratio divided by a width of from 1 to 4 do.

In some embodiments, the above-described stretching step not only increases the CD width of the opening, but also produces alternating ridges and grooves, wherein the opening is located within the groove. The portion of the web contacting the two roll-on ridges is not friction-locked and stretched on top of the ridges while the web between the ridges is stretched out of the plane. The portion of the web stretched out of the plane is further oriented in the z-direction. As a result, a web having ridges and grooves may be formed in which the openings are located in the grooves. It should be noted that if the web is inverted, the groove will be a ridge, the ridge will be a groove, and the opening will now be located within the ridge. The fibers at the top of the ridge and the fibers at the bottom of the groove may be more oriented in the X-Y plane than the fibers in the sidewall.

In the case of a film, the web is thinned and the basis weight is reduced in the stretched region, but within the region of the friction-locked web on the ridge of the roll, the web thickness and basis weight are maintained. This creates a web having alternating areas of higher and lower calipers and alternating areas of higher and lower basis weights wherein the higher caliper and higher area of weights are located at the bottom of the ridge and at the bottom of the ridge, The area with low caliper and lower basis weight is located in the sidewall between them. 11 is a top view of a 25 gsm PE film web 210 (the film is stretched / planarized to exhibit a high basis weight area 212 and a low basis weight area 214). The web 210 further shows ridges R, grooves G, and sidewalls S. The opening 216 is in the groove G. [ As is evident, the high basis weight areas 212 are located in the ridges R and the grooves G, while the low basis weight areas 214 are located in the side walls S.

In the case of nonwoven fabrics, the basis weight is also reduced in the stretched region to produce a web having regions of alternating higher and lower basis weights, wherein the regions of higher basis weights are located at the bottom of the ridge and at the bottom of the ridge, The areas of lower basis weight are located in the sidewalls therebetween. 12 is a top view of a 60 gsm polypropylene nonwoven web 220 (the nonwoven is stretched / planarized to exhibit a high basis weight area 222 and a low basis weight area 224). The web 220 further shows ridges R, grooves G and sidewalls S. The opening 226 is present in the groove G. [ The heat or fusing point 228 may be present at various locations on the web 220. As is evident, the areas of high basis weight 222 are located in the ridges R and the grooves G, and the areas of low basis weight 224 are located in the side walls S. In the case of nonwovens, the web thickness may not be reduced in the stretched area as the fibers can be loosened and moved away from each other. However, the thickness of a portion of the individual fibers may decrease as a result of elongation. It should be noted that the "area" of the web used to characterize the basis weight excludes the opening itself.

As a result of stretching, the web is permanently stretched in the direction of the kidney. When the web is maintained in its corrugated state, most of the increased web width is occupied by the ridges and grooves formed in the web. Alternatively, a tension can be applied to expand the web, which will result in a reduction in the height and frequency of the ridges and grooves, and will reduce the overall basis weight of the web. If desired, the web can be expanded so that the ridges and grooves are no longer present, and the web returns to its planarized state. This modification process can stretch or grow the web by 10%, 15%, 20%, 25%, or more by CD. The amount of permanent elongation and the degree of formation of the ridges and grooves depends on the geometry of the tool, the process conditions and the properties of the material. Typically, this process will permanently stretch or grow the nonwoven web material more than the film material. For example, the web can grow from 165 mm to 190 mm in CD. Suitably, the web has an initial web basis weight, and a lower basis weight zone has a basis weight less than the initial web basis weight.

Figure 13 is a cross-sectional view of the web 220 shown in Figure 12, showing the ridges R, the grooves G and the axis X horizontally drawn through the cross-section of the web; The region above the X axis, but below the top of the ridge, is either hollow or includes a hollow region HA. Likewise, the region below the X-axis, but above the bottom of the groove, is hollow or contains a hollow region HA. Suitably, the web thickness at the top of the ridge and the web thickness at the bottom of the groove are similar. The web thickness at the top of the ridge and the web thickness at the bottom of the groove may be similar to the web thickness at the side wall. Similarly, this means that the thicknesses are within about 60% of each other. Alternatively, the web thickness at the top of the ridge and at the bottom of the groove is greater than the web thickness of the side wall. 14 is a side perspective view of another nonwoven web 230 having ridges 232, grooves 234, and sidewalls 236. 15 is a top perspective view of a 28 gsm polyethylene / polypropylene bicomponent (bico) nonwoven web 240 that includes ridges 242 and grooves 244 and openings 246 and aperture width W _a is a ridge width (W _r ). 16 is a cross-sectional view of the film web 250 showing that it is thinner at the sidewalls 256 than at the top of the ridges 252 or the bottom of the grooves 254. FIG.

The process of interest herein may also utilize a number of transformation steps to more smoothly transform the material or to impart a greater amount of permanent strain. Such a number of transformation steps may be performed by any suitable apparatus described in U.S. Patent Application No. 13 / 094,195 to Lake et al. Suitably, at least the first roll or the second roll also forms a nip with one or more additional rolls thereby further stretching or deforming the web. In one arrangement 200 a ring roll 202 is mounted on a raised-ridge roll 204 which in turn is aligned with another ring roll 206 such that the roll is in a planetary or satellite configuration, . Processes using multiple deformation stages may also be used in devices such as hybrids, closed loops, and shared banks with any suitable number of rolls to perform the desired deformation, or with a relatively small number of rolls in a nested arrangement Can be performed on the evolving device.

Numerous alternative embodiments of the apertured web material and the process for making it are possible. For example, a web material having different areas (including deformed zones and / or unmodified zones) may be provided over their surface with different characteristics therein. The zones may have at least one characteristic selected from the group consisting of ridge height, ridge spacing, aperture size, fiber diameter, film thickness, or combinations thereof. In one embodiment, an apertured web material may be provided having apertures, and in some cases regions of ridges and grooves. The webs disclosed herein may include openings of different sizes and / or regions having ridges and grooves of different sizes and frequencies. The web may include one or more layers. In another embodiment, the film is a micro-textured film comprising an elongated region and an unstretched region, wherein the elongated region has a different micro-textural characteristic than the unstretched region, wherein the micro-textured The properties are selected from the group consisting of open area, size, orientation, and combinations thereof. The webs produced by the process and apparatus described herein may include ridges that extend continuously across the ridged or deformed zone discontinuously extending over the modified zone. To produce such an apertured web material, the ring rolls used may include zones of ridges and grooves. Alternatively, the ring rolls may have zones with ridges of different heights, thereby creating openings having different coupling depths (DOEs), different depths below the raised ridges, and thus different widths and open areas. Alternatively or additionally, the raised ridge rolls may comprise different zones, in which case the ridge heights differ in different zones.

Yes

Example 1

In a non-limiting example for forming openings in a polymer film, such as the web 300 shown in Figure 17 (including the micro-openings 312 and macro-openings 314), at a 3.8 mm bond depth A device comprising a 1.5 mm pitch raised ridge RKA roll interlocked with a 1.5 mm pitch ring roll may be used. The raised ridge RKA rolls have teeth oriented in the longitudinal direction to extend into the MD. The teeth are arranged in a staggered pattern as shown in Fig. 5A. It has a pyramid shape with six sides tapering from the base to the sharp point on the tip, and has a height h _t of 4.7 mm. The value has an angle of inclination of 62 degrees (alpha from Fig. 5B), a sidewall angle (beta from Fig. 5C) on the long side of the value of about 6 degrees, and an inclination angle of the end sphere of 90 degrees (y from Fig. 5E). Ridges extending between teeth on the RKA roll form a non-radial, flat surface. The teeth are finished in the ridge in a semi-truncated form as shown in FIG. 6B. The ridges and grooves extend in the circumferential direction around the ring roll.

There are two different sections of roll-on teeth that are presented to demonstrate the advantages of raised ridges and which are referred to individually as "section A "and" section B. " Section A has a tip-to-tip MD tooth spacing (S _MD ) of 4.9 mm, a cross cut depth of 3.6 mm (d _cc in FIG. 6a) and a resulting ridge height (h _R in FIG. 6a) of 1.1 mm. Section B has an inter-tip MD tooth spacing (S _MD ) of 3.7 mm, a cross cutting depth (d _cc ) of 2.7 mm and a resulting ridge height ( _{r r} ) of 2.0 mm.

The matching ring roll is 1.5 mm pitch with a height of 4.8 mm, a tip radius of 0.12 mm and a sidewall angle of about 4 degrees. Both rolls have a diameter of about 205 mm and are heated to 80 degrees Celsius. The RKA rolls and ring rolls are CD aligned so that the gaps on both sides of the teeth are approximately equal.

Precursor web is a 26 g / m ² basis weight micro-apertured formed polymer film with a blend of LLDPE and LDPE from the RKW-Group of Germany. LLDPE constitutes about 60% of the film composition, LDPE constitute about 30%, and the inert components and fillers, such as TiO ₂ and its carrier resin constituting the remaining 10%. The fine-apertures are 55 meshes (apertures per 25.4 mm (1 inch) in the orthogonal direction) arranged in an equilateral triangular pattern with a center-to-center spacing of about 462 micrometers. The opening diameter is 175 to 200 micrometers and tapers to a conical height of approximately 120 micrometers.

The precursor web is pre-wrapped onto the ring roll before passing between the intermeshed rolls at a linear web speed of 480 meters / minute. The fine-apertured conical side of the film is disposed towards the RKA roll. A coupling depth of 3.8 mm is used. The resulting film is shown in low magnification in Figs. 18A and 18B. The open area of the film (% of film area with open openings), aperture length, and aperture width were measured using a trade name of IN-SIGHT from Cognex Corporation, Natik, Mass. It is measured with the same vision system as can be purchased. The open area, length and width comparisons of section A (FIG. 18A) versus section B (FIG. 18B) are shown in the table below. 18A and 18B show film webs 320 and 340 having micro-apertures 322 and 342 and apertures 324 and 344, respectively.

Example 2

In one non-limiting example for making a corrugated web with openings in the grooves, an apparatus comprising a 2.0 mm pitch raised ridge RKA roll intermeshed with a 2.0 mm pitch ring roll at 6.3 mm bond depth may be used. The raised ridge RKA rolls have teeth oriented in the longitudinal direction to extend into the MD, and the ridges and grooves extend in the circumferential direction around the ring roll. The teeth are arranged in a staggered pattern as shown in Fig. 5A. It has a pyramid shape with four sides tapering from the base to the sharp point on the tip, and has a height h _t of 6.9 mm. The value has a subtended angle of inclination of 57 degrees (alpha from Fig. 5B) and a sidewall angle (beta from Fig. 5C) on the long side of the value of about 5 degrees. The ridge that runs between the teeth on the RKA roll forms a flat, non-rounded surface. The teeth are finished in the ridge in a non-truncated form as shown in Figure 6c. The tooth has an inter-tip MD tooth spacing (S _MD ) of 8.0 mm, a cross cutting depth of 3.7 mm (d _cc in Fig. 6a) and a resulting ridge height (h _R in Fig. 6a) of 3.2 mm.

The matching ring roll is 2.0 mm pitch with a height of 6.9 mm, a tip radius of 0.12 mm and a sidewall angle of about 4 degrees. Both rolls have a diameter of about 142 mm. The RKA rolls and ring rolls are CD aligned so that the gaps on both sides of the teeth are approximately equal.

The first precursor web is a 25 g / m2 basis weight polymer film with a blend of LLDPE and LDPE from Clopay Plastics Co. of Ohio, USA. The precursor web is pre-wrapped in a ring roll before passing between intermeshed rolls at a linear web speed of 20 meters / minute. The resulting corrugated, apertured film is shown in FIG. 11 (the film is stretched / planarized to show high and low basis weight areas). Images were taken at low magnification using an optical microscope, such as can be purchased from Allasso Industries, using red LED backlighting.

The second precursor web is a thermally bonded polypropylene nonwoven fabric having a basis weight of 60 g / m < 2 > obtained from Fiberweb, France. The precursor web is pre-wrapped in a ring roll before passing between intermeshed rolls at a linear web speed of 20 meters / minute. The resultant corrugated, apertured nonwoven fabric is shown in Figure 12 (top view; the web is stretched / planarized to show high and low basis weight regions), Figure 13 (cross-sectional view), Figure 19a (raised ridge RKA side), and Figure 19b Roll side). The images were taken at low magnification using an optical microscope such as can be purchased from Allasso Industries. 19A and 19B, web 400 includes alternating ridges 402 and grooves 404; The opening 406 is in the groove 404.

It is to be understood that the dimensions and values disclosed herein are not strictly limited to the exact numerical values mentioned. Instead, each such dimension, unless otherwise specified, is intended to mean both the recited value and the functionally equivalent range near its value. For example, a dimension disclosed as "40 mm" would mean "about 40 mm ". Moreover, the numerical ranges referred to herein include not only individual numerical values but also any other narrower ranges within the range. It is to be understood that all maximum numerical limitations given throughout this specification are intended to encompass all such lower numerical limitations as if they were expressly recited in this specification. All minimum numerical limitations presented throughout this specification are intended to encompass all such higher numerical limitations as if they were expressly set forth herein. All numerical ranges presented throughout this specification will include all such narrower numerical ranges within these broader numerical ranges as if they were all expressly set forth herein.

All documents cited in the specification for carrying out the invention are incorporated herein by reference in their entirety; The citation of any document should not be construed as an admission that this is prior art with respect to the present invention. In addition, where any meaning or definition of a term in the written document conflicts with any meaning or definition of a term in the reference contained in the reference, the meaning or definition given to the term in the documented document shall prevail will be.

Although specific embodiments of the invention have been illustrated and described, it will be apparent 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 the invention.

Claims (15)

An apparatus comprising two intermeshing counter-rotating rolls forming a nip therebetween,
a) a first roll of generally cylindrical shape having a surface, a circumference and an axis,
A plurality of circumferential first ridges and circumferential first grooves on the surface of the roll, the first ridges having a top surface, the first grooves having a bottom surface; And
A plurality of spaced apart teeth extending outwardly from an upper surface of the first ridges, each tooth tapering from a top surface to a tip, the upper surface of the first ridge having tips The first roll being located between the bottom surfaces of the first grooves; And
b) a substantially cylindrical second roll comprising a plurality of successive circumferential second ridges and a second groove. 2. The method of claim 1 wherein the first roll comprises a cross-cut depth measured from the top surface of the first ridge to the tip of the tooth and the nip comprises a bond depth between the first roll and the second roll, wherein the depth of engagement is greater than the cross-cut depth, and preferably the bond depth is greater than the cross-cut depth by at least 0.1 mm. 3. The apparatus according to claim 1 or 2, wherein the nip comprises a coupling depth between the first roll and the second roll, and the coupling depth is between 3 mm and 4 mm. 4. A method according to any one of claims 1 to 3, wherein the first roll comprises a cross-directional width and the distance between the top surfaces of the first ridges and the bottom surfaces of the first grooves is less than the circumferential periphery of the first roll And substantially the same across the cross-directional width. 4. A method according to any one of claims 1 to 3, wherein the first roll comprises a cross-directional width and the distance between the top surfaces of the first ridges and the bottom surfaces of the first grooves is less than the circumferential periphery of the first roll Or across a cross-directional width. 6. The device according to any one of claims 1 to 5, wherein the teeth are faceted and comprise at least four or six sides. 7. A method according to any one of claims 1 to 6, wherein the portions of the teeth where the ridge surfaces meet are of truncated, semi-truncated, non-truncated, To provide a selected geometric shape. 8. The device according to any one of claims 1 to 7, wherein the first ridge has a height and the height is at least 20% of the height of the tooth. 9. The apparatus of any one of claims 1 to 8, wherein the upper surface of the first ridges is selected from the group consisting of radial, non-radial, or combinations thereof. 10. The device according to any one of the preceding claims, wherein the second roll is a ring roll having ridges of different heights in the circumferential or axial direction. A method for deforming a web comprising the steps of feeding a precursor web into a nip formed between two interdigitated rolls,
a) a first roll of generally cylindrical shape having a surface, a circumference and an axis,
1) a plurality of first ridges and a first groove extending around the circumference of the roll on the surface of the roll, said first ridges having an upper surface, said first grooves having a bottom surface; And
2) a plurality of spaced teeth extending outwardly from the upper surface of the first ridges, the teeth having tips, the upper surface of the first ridges being disposed between the tips of the teeth and the bottom surface of the first grooves; - the first roll; And
b) a generally cylindrical second roll comprising a plurality of successive, circumferential ridges and grooves, the second ridges having an upper surface and the second grooves having a bottom surface;
The upper portion of at least a portion of the ridges on the first roll extending inwardly toward the axis of the second roll at a depth past the top of at least a portion of the second ridges on the second roll when the web is fed into the nip, The web is (i) apertured by the teeth in a plurality of spaced apart first positions to form a plurality of spaced apart openings; (ii) is stretched in the cross-machine direction by the intermeshing rolls. 16. The method of claim 15, wherein at least the first roll or the second roll also forms a nip with one or more additional rolls thereby further stretching or deforming the web. 16. The method of claim 15, wherein precursor webs and intermeshed rolls are not heated. 16. The method of claim 15, wherein the precursor web is heated by wrapping it around a heated roll at 50-200 degrees Celsius. 14. A web produced by an apparatus or method according to any one of claims 1 to 14, wherein the web is preferably a nonwoven fabric selected from the group consisting of LLDPE, LDPE, HDPE, or a combination thereof, a laminate, A web comprising a film.

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