JP5956062B2 - Device for opening and stretching a web - Google Patents

Description

  The present invention is directed to an open web material and an apparatus and method for making such a material by opening and stretching the web.

  Various methods and devices for opening, deforming and / or stretching a web are disclosed in the patent literature. With an opening method such as a rotary blade opening, it is difficult to produce a web with dense openings having the desired width in the cross machine direction (“CD”). In order to closely arrange the rows of openings, an activation tooth with a very small depression angle may be provided. However, this method has a problem because even if the engagement depth (interference between the starting tooth roll and the counterpart ring roll) is large, an opening that does not have a sufficient opening width is produced in the CD. . The resulting opening is often longer in the machine direction, resulting in a slit-like appearance, a small opening area, and a concentration of potential stresses that cause tearing during use. The production of slits, small opening areas, and openings is particularly problematic when using stronger and more tear resistant webs. Round or tapered hot pin openings are common but have the disadvantage of requiring higher overlay accuracy with the mating roll and typically result in larger opening spacing. Round or tapered hot pin openings are typically operated at slower linear velocities.

  Although it is possible to stretch the aperture web after ring roll processing, it is not possible to align the apertures in the subsequent ring roll stretching process, which can result in alternating aperture dimension rows. Aligning the features in the transverse direction using a later process is difficult because the diffusion of the substrate can change. Moreover, after a ring roll process, a web becomes remarkably weak and may become easy to tear.

  It would be desirable to make a web with separate, dense openings having a larger CD width than previously possible. There is a need for an open web that is stronger in the cross machine direction and therefore does not tear easily in the cross machine direction. There is a need for a method of making open webs that are larger, wider, and have larger openings. There is also a need for an apparatus that can open the web such that the opening has a desired greater width in the cross machine direction.

  There are many known processes for making webs with ridges and grooves (eg, ring roll processing). There are also many known processes for making webs with openings (eg, hot pin openings). However, it is difficult to produce a corrugated web having alternating ridges and grooves aligned with a particular opening pattern. There is a process for ring rolling after the formation of the micro-openings, but this results in a flat web without corrugations. Webs with ridges and grooves (flat strips) can be formed by air or water jets on the patterned belt. However, air or water injection is a much slower process than the invention described herein and requires more energy. Furthermore, the ridges are not hollow and can hold more fluid.

  It is desirable to produce a web having alternating ridges and grooves with openings located at specific locations within the web (eg, grooves or ridges). There is a need for an apertured web having an aligned corrugated pattern.

  These are all objectives of the present invention, and the embodiments described herein can realize various combinations of these objectives. Particular embodiments need not embody all objectives, but may embody all objectives.

  The present invention is directed to an open (and often corrugated) web material and an apparatus and method for opening the web to make such a material. Such materials include products components such as absorbent articles (eg, topsheets, backsheets, acquisition layers, liquid treatment layers, and absorbent cores), packaging (eg, flow wrap, shrink wrap films, and Plastic bags, etc.), wipes, facial tissues, toilet paper, paper towels and the like. There are numerous non-limiting embodiments of the present invention.

  The present invention relates to an apparatus including two engaging forming structures forming a nip therebetween, the apparatus being a first forming structure, wherein a plurality of first ridges and first grooves on a surface of the forming structure. The first ridge has an upper surface, the first groove has a lower surface, and a plurality of spaced teeth extend outwardly from the upper surface of the first ridge, each tooth having an opening. A first forming structure and a plurality of continuous second ridges and second grooves, wherein the upper surface of the first ridge is located between the tip of the tooth and the lower surface of the first groove. A second forming structure including

  The present invention further relates to an apparatus comprising two engaging counter rotating rolls forming a nip therebetween, the apparatus being a substantially cylindrical first roll, the first roll comprising a surface, a circumferential portion. The first roll includes a plurality of circumferential first ridges and circumferential first grooves on the surface of the roll, the first ridge having an upper surface; The first groove has a lower surface, and a plurality of spaced teeth extend outward from the upper surface of the first ridge, each tooth tapering from the upper surface to the tip, and the upper surface of the first ridge is A first roll and a substantially cylindrical second roll located between the tip of the tooth and the lower surface of the first groove, wherein the second roll is a plurality of continuous circumferential second rolls; A second roll including two ridges and a second groove.

  The present invention further relates to a process for deforming a web using an apparatus, the process comprising supplying a precursor web to a nip formed between two engagement rolls. The roll is a) a substantially cylindrical first roll, the first roll having a surface, a circumference, and an axis, the first roll around the circumference of the roll on the surface of the roll A plurality of extending first ridges and a first groove, wherein the first ridge has an upper surface, the first groove has a lower surface, and a plurality of spaced teeth has an upper surface of the first ridge. A first roll extending outward from the tooth, the tooth having a tip, and the upper surface of the first ridge is disposed between the tip of the tooth and the lower surface of the first groove; b ) A substantially cylindrical second roll, the second roll comprising a plurality of continuous circumferential ridges and grooves, the second ridge having an upper surface; The second groove has a lower surface, and when the web is fed to the nip, at least some tops of the ridges on the first roll are on the second roll. Extending inward toward the axis of the second roll to a depth beyond at least some of the tops of the second ridges, the web being (i) opened by the teeth at a plurality of spaced first positions, And (ii) stretched in the cross machine direction by the engagement roll.

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 clarify the claimed subject matter.
1 is a perspective view of a prior art pair of ring rolls for deforming a web. FIG. 1 is a perspective view of a prior art pair of rolls (rotating blade opening (or “RKA”) roll and ring roll) for opening a web. FIG. 2B is a side view of the prior art pair of rolls shown in FIG. 2A. FIG. FIG. 2B is an enlarged side view of the nip between the rolls shown in FIG. 2A. 2B is a plan view of a representative prior art web that may be formed by use of the roll shown in FIG. 2A. FIG. 1 is a perspective view of a pair of rolls for use in the apparatus and process described herein, one roll being a staggered “convex ridge” RKA roll and the other roll being a ring roll. 3B is an enlarged side view of the nip between the rolls shown in FIG. 3A. FIG. FIG. 6 is a perspective view of a portion of the surface of a representative raised ridge RKA roll. It is a perspective view of a part of the surface of a typical ring roll. FIG. 3 is a perspective view of a portion of the surface of a representative convex raised SELF roll. FIG. 6 is a perspective view of a portion of the surface of another representative raised ridge RKA roll. 5B is a side view of the tooth arrangement shown in FIG. 5A. FIG. FIG. 5B is an end view of the tooth arrangement shown in FIG. 5A. FIG. 5B is a plan view of the tooth arrangement shown in FIG. 5A. FIG. 5B is a cross-sectional view along line DD of the tooth arrangement shown in FIG. 5B. FIG. 5B is a cross-sectional view along line EE of the tooth arrangement shown in FIG. 5B. FIG. 2 is a front view of a first representative group of teeth, with the teeth tapered and truncated. FIG. 3 is a front view of a second representative group of teeth, with the teeth tapered and half truncated. FIG. 3 is a front view of a second representative group of teeth, with the teeth tapered and non-truncated. FIG. 5 is a schematic view of a tooth pattern in which end face angle γ and ridge finish can be achieved in a single helical machining process. FIG. 6 is an enlarged side view of a portion of the surface of an alternative raised ridge RKA roll. 3B is a plan view of one embodiment of a web that can be formed by using the variation of the roll of FIG. 3A. FIG. FIG. 9B is an enlarged view of one of the openings shown in FIG. 9A. FIG. 6 is a side view of another embodiment of an apparatus for opening a web with three rolls in a planetary array. FIG. 2 is a plan view of a 25 gsm PE film web (the film is stretched / flattened to show high and low basis weight regions). FIG. 2 is a plan view of a 60 gsm PP nonwoven web (the nonwoven is stretched / flattened to show high and low basis weight regions). It is sectional drawing of the web shown by FIG. FIG. 6 is a side perspective view of another nonwoven web. 1 is a top perspective view of a nonwoven web. FIG. It is sectional drawing of a film web. 1 is a plan view of an apertured film web described in Example 1. FIG. 1 is a plan view of an apertured film web described in Example 1. FIG. 1 is a plan view of an apertured film web described in Example 1. FIG. 3 is a top perspective view of an open nonwoven web as described in Example 2. FIG. FIG. 19B is a bottom perspective view of the web of FIG. 19A.

  The following text provides a general description of many different embodiments of the present invention. This description is to be construed as merely illustrative, and it is impractical, if not impossible, to describe all possible embodiments, so that all possible embodiments are described. Not what you want. Any feature, characteristic, component, composition, ingredient, product, process, or methodology described herein can be deleted, and any other feature described herein, It will be understood that properties, components, compositions, ingredients, products, processes, or methodologies can be combined or replaced in whole or in part. Numerous alternative embodiments can be implemented using either the latest technology or technology developed after the filing date of this patent, but such embodiments are still claimed. It will be included in the range. All publications and patents cited herein are hereby incorporated by reference.

  Also, as used herein, the term “_” is defined herein to mean… ”or similar terms are used herein to explicitly define terms. Unless otherwise stated, it is to be understood that there is no intent to limit the meaning of the term, either express or implied, beyond its plain or ordinary meaning; No part of this patent should be construed as being limited in scope based on any sentence set forth. Neither term is intended to be essential to the invention, unless stated as essential to the invention. As long as any term in the claims at the end of this patent is mentioned in this patent in a manner consistent with a single meaning, it is simply understood so as not to confuse the reader. This is done solely for the purpose of facilitating purposes, and is not intended to limit the terminology of the claims to its single meaning by implications or otherwise. Finally, unless the elements of a claim are defined by elaborating the “meaning” and function of the word without any structural details, the scope of the claim elements is It is not intended to be construed based on the application of Article 112, sixth paragraph of the Act.

  The present invention allows for an open web that is stronger in the cross machine direction and therefore does not tear easily in the cross machine direction. A process is described for making an open web with discrete, dense openings having a desired greater width in the cross machine direction. The process can also create a structure with alternating ridges and grooves, with openings included in the grooves. An apparatus is also described that can open a web having a desired, separate, closely packed, wider opening in the cross machine direction.

  As used herein, the term “absorbent article” includes disposable articles such as sanitary napkins, panty liners, tampons, interlabial devices, wound dressings, diapers, adult incontinence articles, wipes and the like. Furthermore, absorbent members made by the processes and apparatus disclosed herein find utility on other webs, such as polishing pads, dry mop pads (eg, SWIFFER® pads), etc. be able to. At least some of such absorbent articles are intended for menstrual or absorption of body fluids such as blood, vaginal secretions, urine, and stool. The wipe may be used to absorb bodily fluids or may be used for other purposes such as cleaning the surface. The various absorbent articles described above typically include a liquid permeable 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 a configuration of an absorbent article that provides one or more of liquid handling functions, eg, liquid acquisition, liquid distribution, liquid transport, liquid storage, etc. Points to the element. When an absorptive member consists of a constituent of an absorptive core, an absorptive member can consist of the absorptive core whole or only a part of absorptive core.

  As used herein, the term “opening” refers to a hole. The opening may penetrate the web completely (the “two-dimensional” opening), so that the material around the opening is flush with the web before the opening is formed, or around the opening A hole may be formed through which at least a portion of the material is extruded from the plane of the web. In the latter case, the opening may resemble a “three-dimensional” opening. Three-dimensional openings are generally loaded and retain a larger opening area. As used herein, the term “opened” refers to a web that includes a plurality of openings.

  As used herein, the term “component” of an absorbent article includes topsheets, acquisition layers, liquid treatment layers, absorbent cores or layers of absorbent cores, backsheets, and barriers such as barrier layers and barrier cuffs. Refers to the individual components of the absorbent article.

  As used herein, the term “corrugated” or “corrugated” refers to a three-dimensional web topography comprising a plurality of generally parallel alternating ridges and grooves, where the ridges and grooves are (web cross-sections). Waveforms about axis X (drawn horizontally through). The ridges and grooves may be similarly corrugated on either side of the shaft, or may be offset.

  As used herein, the term “cross-machine 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 applied stress or strain.

  As used herein, the term “engagement depth” (“DOE”) means the degree of engagement between two rolls. The distance from the outermost tip of the tooth or ridge on the first roll to the outermost tip of the tooth or ridge on the second roll is measured. The terms “engagement” or “interengagement” as used herein, the teeth / ridges on one roll extend toward the surface of the other roll, and at least some of the teeth / ridges are Refers to a configuration having portions extending between and below the imaginary plane drawn through the tips of the teeth / ridges on the surface of the other roll.

  As used herein, the term “separate” means independent or not connected. When the term “separate” is used for a tooth on a convex raised roll, the distal end (or radially outermost) of the tooth is independent in all directions (including machine and cross machine) Meaning that it is present or not connected (however, the tooth base may be formed in the same surface of the roll, for example). For example, the ridges on the ring roll are not considered separate.

  As used herein, the term “disposable” describes absorbent articles and other products that are not intended to be washed or otherwise restored or reused as absorbent articles or products. (Ie they are intended to be discarded after use, preferably recycled, composted or otherwise disposed of in an environmentally compatible manner).

  As used herein, the term “hollow” describes ridges and grooves present in the web produced by the apparatus and process described herein, where the ridges and grooves are free of web material. Includes space. For example, the web includes a ridge, a groove, and an X-axis that is pulled horizontally through the cross-section of the web, and the region above the X-axis and below the top of the ridge is hollow or includes a hollow region. Including. Similarly, the region below the X axis and above the bottom of the groove is hollow or includes a hollow region.

  As used herein, the term “machine direction” or “MD” means the path that a material, such as a web, travels through the manufacturing process.

  As used herein, the term “macroscopic” means that a person with 20/20 visual acuity is easy if the vertical distance between the viewer's eyes and the web is about 30 cm (12 inches). Refers to a structural feature or element that can be seen and clearly identified. Conversely, as used herein, the term “microscopic” refers to such a feature that cannot be easily seen and clearly identified under such conditions.

  As used herein, the term “ring roll” or “ring roll processing” comprises a counter-rotating roll, an engagement belt, or an engagement plate that contains at least a portion of a continuous ridge and groove. Refers to a process using a deformable member, where the engaging ridges (or protrusions) and grooves (or recesses) of the deformable member engage and stretch the web inserted between them. Unless otherwise stated, the ring roll alone does not open the web. For ring rolls, depending on the orientation of the ridges and grooves, the deformation member is arranged to stretch the web at an angle to the CD or MD in the cross machine direction, machine direction, or spiral direction Can do. It should be understood that embodiments described herein relating to one direction need not describe a direction.

  As used herein, the term “rotary blade opening” (RKA) refers to a process and apparatus that uses an engaging deformable member (or roll), where one or more rolls include a plurality of teeth. To produce an open web (or possibly a three-dimensional open web) as disclosed in US Patent Application Publication Nos. 2005/0064136 (A1) and 2006/0087053 (A1), The web may be sharpened to cut and deform.

  The term “SELF” or “SELF'ing” refers to the technique of Procter & Gamble, and SELF is an abbreviation for Structural Elastic Like Film. The patterns produced by the process, apparatus, and SELF are described in US Pat. Nos. 5,518,801, 5,691,035, 5,723,087, 5,891,544, No. 5,916,663, No. 6,027,483, and No. 7,527,615 (B2). The process was originally developed using a tooth shape that deforms the polymer film without creating openings, but a tuft (in the case of non-wovens) or tent (with a film) with openings at the front and rear ends. Other tooth shapes have been developed that further contribute to the formation of A process for forming tufts with openings in a nonwoven web using SELF processing is disclosed in US Pat. No. 7,682,686 (B2).

  As used herein, the term “tooth” refers to any element on the surface of a roll that can open a web.

I. Opening web material Although the term “opening web material” is used herein, the purpose is to create components such as absorbent members (or non-absorbent members) for absorbent articles from such open web materials That is. In such cases, the open web material will be cut into individual components for the absorbent article (eg, topsheet, backsheet, acquisition layer, absorbent core, etc.). In the case of webs used in absorbent articles, such new structures provide improved properties (such as improved flexibility, fluid handling, or other properties) at predetermined portions of the web. Things can be included. These open webs form various other components such as packaging products (eg, flow wraps, shrink wrap films, and plastic bags), wipes, facial tissue, toilet paper, paper towels, etc. It may be cut.

  Separate, dense openings with greater width in the CD direction that cannot be made with current methods and tools can be provided to the web and components formed therefrom. The new opening has a larger opening area and a smaller aspect ratio (opening length: opening width) than an opening with an equivalent opening area achievable with the prior art (see FIG. 2D). For films) provides improved web strength.

  Furthermore, the web made with this new technology has a unique, more textured appearance. The textured web may include alternating ridges and grooves, with the openings intentionally included within the grooves. If an open web is used in the absorbent article, the web can provide better fluid acquisition, breathability, or separation from the body, thus promoting a dry and clean sensation. For example, in a sanitary napkin, the opening located in the groove serves to move fluid from the topsheet to the absorbent member below. Not only do the openings provide these benefits, but any corrugation present in the final web can further support these benefits. For example, corrugations provide at least partial contact with the body that improves breathability, provides a dry sensation, may irritate the skin or feel uncomfortable, wet / dirty Less contact with the surface. In the case of a sanitary napkin, the corrugation can cause fluid to flow longitudinally along the sanitary napkin and hold the fluid away from the side edges of the sanitary napkin.

  The web to be opened (or “precursor web”) can be any suitable deformable, such as a woven fabric, nonwoven fabric, film, flat film, microtextured film, any combination of the above materials, or a laminate. Material can be included. As used herein, the term “nonwoven web” refers to a repeating pattern as in a woven or knitted fabric that is interlaced with individual fibers or yarns but typically does not have randomly oriented fibers. It refers to a web having a non-intricate structure. The nonwoven web may or may not include a thermal bond point. This includes paper substrates such as tissue, dry wrap, linerboard, filter paper, and combinations thereof. Nonwoven webs or fabrics have been formed from a number of processes, including, for example, meltblown, spunbond, hydroentangled, aerated, wet, air-pass wet papermaking processes, and bonded card web processes including card thermal bonding. Depending on the molding process, the nonwoven web may or may not include thermal bond points. The film material may be single layer, multilayer, embossed, or microtextured. The woven, non-woven, film, combination, or laminate may be made from any suitable material, including but not limited to natural materials, synthetic materials, and combinations thereof. Suitable natural materials include cellulose, cotton linter, bagasse, wool fiber, silk fiber. In some embodiments, the web material may be substantially free of cellulose and / or free of paper material. In other embodiments, the processes described herein may be performed on a precursor material that includes cellulose. Suitable synthetic materials include, but are not limited to, rayon and polymeric materials. Suitable polymeric materials include polyethylene (PE) (eg, linear low density polyethylene (LLDPE), low density polyethylene (LDPE), high density polyethylene (HDPE), etc.), polyester, polyethylene terephthalate (PET), and polypropylene ( PP)), but is not limited to these. Any of the above materials can include used recycled material. The devices described herein operate using a wide range of materials and lower cost materials. For example, some devices use multiple layers of general purpose spunbond nonwovens with different chemical and mechanical properties to control the degree of intermixing of two or more layers of nonwovens with different fiber formulations and compositions, or films. can do. In addition, the device can operate directly on-line (and does not lose loft for roll compression / storage).

  Various polymers can be used to make the desired web. Potential materials include biological polyethylene (bio-PE), biological polypropylene (bio-PP), biological polyethylene terephthalate (bio-PET), and biological poly (ethylene-2,5-furandicarboxylate) ( Bio-polymers made from non-petroleum sources such as bio-PEF). These materials may be partially or fully derived from at least one renewable resource, which refers to a natural resource that can be replenished within a period of 100 years. Renewable resources include plants, animals, fish, bacteria, fungi, and forest products, and may be naturally occurring, hybrid, or genetically modified organisms. Natural resources such as crude oil, coal, and peat that take longer than 100 years to form are not considered renewable resources. Other polymers derived from non-petroleum sources include starch-based polymers and cellulose derivatives. In addition, recycled resin such as used regrind r-HDPE, r-LLDPE, r-LDPE, r-PET, r-PEF, or r-PP can be used at 100% or mixed with various resins. Can be used. Polymers derived from renewable resources and recycled resins can be used as such or mixed at various levels with petroleum-based polymers to control costs. Sources and methods for producing polymers from non-petroleum sources can be found in US Pat. No. 8,063,064 (B1) and US Published Application 2011/0319849 (A1).

  The present invention is directed to an open web material and an apparatus and process for opening and stretching the web to create such a material that overcomes one or more disadvantages of the prior art. Stretching (or stretching) the web is beneficial because it allows cost reduction due to a decrease in the overall basis weight of the web. By stretching after opening in the same process step, a wider and more favorable opening is made in the web material. Here, the opening and extension are performed in a single operation and aligned so that the extension is performed while the teeth are still penetrating the material, and thus the opening is not crushed during extension. The additional stretching process not only allows the opening to be wider, but also has the potential to produce a web with a corrugated appearance. This combination of stretching after opening must be accurately aligned. If opening and stretching are separate processes as in the prior art, the opening may close without being aligned with the stretching ring roll. Also, the webs made with this new process are more flexible and can be pleated from the stretching process (relaxed and / or thinned fibers and / or films). Thinner webs are generally desirable because they can hold less fluid. This is important because when the web is used as a topsheet for an absorbent article, there is less saturation in the topsheet.

  In one non-limiting embodiment, the open web material comprises a web having separate openings formed therein. The web has a first surface and a second surface opposite the first surface. The web includes a substantially non-open area (ie, a land) that surrounds a plurality of separate openings.

The openings are dense within a relatively small area. For example, the 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 within an area of 645 mm ² (1 square inch) may be 4, 25, 100, 250, 500, 1000, or 3000 or more. The number of openings in a 25.4 mm (1 inch) square area is marked by marking a 25.4 mm (1 inch) by 2.54 cm (1 inch) square area on the material with a tapered pen or marker. 1st, 2nd, 3rd, 4th (1 inch) square boundaries located entirely or partially on the boundary. . . It can be determined by counting the number of openings. A low power microscope or other magnifying aid can be used to assist in the visibility of the openings in the material if necessary. The opening may be any suitable shape.

The opening may be any suitable dimension. Typically, the opening will be macroscopic. The planar view 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 a microscopic opening having a planar view area of less than 0.5 mm ² .

  In addition to the openings, the web may include alternating ridges and grooves, the openings being disposed in the grooves. The ridges may extend continuously or may form discontinuous ridges in the deformation region of the web. The groove may extend continuously with openings spaced apart at regular intervals within the groove. Note that if the web is turned upside down, the groove will become a ridge, the ridge will become a groove, and the opening will now be located in the ridge. The opening may be two-dimensional or three-dimensional, depending on 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 side of the ridge and the side of the groove are oriented in the z direction from the top of the ridge and the bottom of the groove.

  In the case of a film, the side of the ridge and the side of the groove may be thinner than the top of the ridge and the bottom of the groove as a result of the stretching process and may have a small basis weight. This results in a web with alternating regions of high thickness and basis weight and regions of low thickness and basis weight, where the regions with large thickness and basis weight are located at the top of the ridge and the bottom of the groove, The region with a small thickness and basis weight is located on the middle side wall. Alternating basis weight provides a thin / flexible area for comfort and maintenance of thickness for strength.

  In the case of non-woven fabric, the basis weight decreases in the stretched region, and similarly, a web in which regions having a large basis weight and regions having a small basis weight are alternately formed is located, and the region having a large basis weight is located at the top of the raised portion and the bottom of the groove. The region with a small basis weight is located on the middle side wall. In the case of nonwovens, the web thickness may not decrease in the stretch region because the fibers can unwind and move away from each other. However, the thickness of some individual fibers may decrease as a result of stretching, 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 can be greater than the average fiber diameter at the sidewall. The web thickness of the substrate is not significantly different as long as it is pawled by the ridges and grooves. Although the web is textured, the ridges and grooves are deformed from the plane, so that when the ridges and grooves are not filled, but rather form a hollow region, the local web thickness at the ridges and grooves. There is no big difference. Hollow ridges cannot hold as much fluid as filled ridges and can provide a drying benefit when used as a topsheet in absorbent articles. As a result of stretching, the web is permanently stretched in the direction of stretching. Suitably, the web thickness in the stretch region is between 20% and 80% of the original web thickness.

II. Prior art devices for deforming web materials Prior art methods are particularly suitable for making openings with wider dimensions in the cross machine direction, using tough or tear resistant films. Absent. Thus, in order to obtain an opening in the web material that has a larger dimension than the cross-machine dimension obtained with the prior art method, the opening teeth still penetrate the web in the same process step (i.e. in the same nip). It is desirable to design a process that can stretch after opening. Prior art methods are also suitable for making webs having alternating ridges and grooves with openings located in the grooves using high speed openings and stretching means as described herein. Absent.

  FIG. 1 shows a first prior art apparatus 10 where rolls 12 and 14 are referred to herein as ring rolls. The rolls 12, 14 are located on corresponding rotating shafts having a rotation axis A arranged in a parallel relationship in the case of the rolls of other devices shown and described herein. In all embodiments described herein, the roll is non-contact and driven axially. In this embodiment, the surface of the roll has a plurality of alternating grooves 16 and ridges 18 that extend 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 of such rolls can be used in various embodiments of the apparatus described herein.

  In the embodiment shown in FIG. 1 and various other embodiments described herein, the rolls are engaged or at least partially engaged. As shown in FIG. 1, the roll typically rotates in the opposite direction (ie, the roll rotates in the reverse direction). This also applies to the other embodiments described herein.

  2A-2C show a second prior art device 20, where the upper roll 22 is a rotary blade aperture (or “RKA”) roll and the lower roll 24 is referred to herein as a ring roll. . The apparatus includes a pair of counter-rotating engagement rolls, the upper roll 22 includes pyramidal teeth 30 having four or more side surfaces, the side surfaces being substantially triangular and tapering from the base to the tip. The lower roll 24 includes a groove 26 and a raised portion 28 extending in the circumferential direction. The teeth 30 are arranged in spaced circumferential rows with grooves in between. The teeth 30 extend from the upper roll 22 at the base, and the tooth base has a cross-sectional length dimension that is greater than the cross-sectional width dimension. Typically, the opening is formed in the web material when the teeth 30 on the RKA roll 22 engage the grooves 26 on the ring roll 24. With regard to tooth height, tooth spacing, pitch, engagement depth, and other manufacturing parameters, the RKA and RKA devices are the same as those described in US 2006/0087053 (A1). It may be.

  The RKA roll 22 shown in FIG. 2A comprises a staggered tooth pattern (as opposed to standard). As used herein, the term “staggered” means that adjacent teeth do not line up in a CD. As used herein, the term “standard” means that adjacent teeth line up in a CD and thus are not staggered. As shown in FIG. 2C, the rolls 22 and 24 are aligned in the cross machine direction so that the teeth 30 on the RKA roll 22 are aligned with the grooves 26 on the ring roll 24. As the teeth 30 penetrate the web, the ridges 28 on the mating ring roll support the web so that the teeth 30 can penetrate the web and at the same time form openings in the opposite direction.

  FIG. 2D shows a plan view of an exemplary prior art web 34 that may be manufactured with an apparatus as shown in FIGS. The resulting web 34 includes lands 36 that surround an opening 38. The opening 38 formed in the prior art device as in FIGS. 2A-2C comprises a length L in the machine direction and a width W in the cross machine direction. These openings are typically slit-shaped, particularly in tougher and more resilient webs, and have a width W that is significantly smaller than the length L.

III. Apparatus and process using rolls with teeth extending from convex ridges to open web material In general, the apparatus includes two engaging forming structures that form a nip therebetween. Forming structures can include rollers, plates, belts, sleeves, other structures that can impart texture to the web, or combinations thereof. The first forming structure includes a plurality of first ridges and first grooves on the surface of the forming structure, the first ridges having an upper surface, and the first grooves having a lower surface. The first forming structure further includes a plurality of spaced teeth extending outwardly from the upper surface of the first ridge, each tooth being capable of forming an opening, the upper surface of the first ridge being It is located between the tip of the tooth and the lower surface of the first groove. The second forming structure includes a plurality of continuous second ridges and second grooves.

  More specifically, the apparatus includes a pair of counter-rotating engagement rolls that form a single nip N therebetween. Although the apparatus is described herein primarily for convenience, primarily with respect to rolls, it should be understood that the description will apply to any suitable apparatus that may include any suitable forming member type. These forming members include, but are not limited to, a pair of rolls, a pair of plates, a conveyor having packs (or small plates), a belt, or a combination thereof. The first roll and the second roll each include surfaces 106, 108 with a plurality of circumferentially extending ridges and grooves. Alternatively, the ridges and grooves may extend in a direction parallel to the roll axis as long as they engage a roll having ridges and grooves extending in the same direction. The first roll further includes a plurality of spaced teeth, the teeth extending outward from the top surface of the ridge. This produces a “convex ridge”. The raised portion of the second roll extends toward the axis of the first roll to a depth that exceeds at least some of the tops of the raised portions on the first roll. In this way, the initial engagement of the teeth creates an opening, and when the engagement proceeds to a depth below the convex ridge, the opening is then stretched in the cross machine direction. In one process step, by opening first and then stretching while the teeth are still penetrating the web, the resulting opening is a standard tooth as shown in FIGS. 2A-2D above. It has a larger width in the transverse direction of the machine than the opening produced by the attached roll.

  The openings of the present invention are considerably larger, especially when using tougher films (eg, those containing high concentrations of LLDPE), with a smaller aspect ratio (opening length: opening width) than prior art openings. An opening area. The new tooth shape helps to increase the opening area at lower tool temperatures and can create openings in the web that cannot be opened with conventional tooth shapes. The new tool geometry provides the ability to open the web at lower temperatures (eg, 35-70 ° C.) or even at ambient temperatures without the need for equipment heating. Furthermore, the costs associated with making this tool over conventional tools are reduced from a minimum, especially because less metal is removed. Thus, room temperature precursor webs can be used. In one embodiment, the precursor web and engagement roll are not heated. Alternatively, an entirely preheated web may be used. Alternatively, the compartmentalized preheating of the web may cause openings in some sections and temporary changes in other sections. Preheating can be accomplished by wrapping around the RKA roll prior to engagement (with various wrapping times possible prior to engagement) or by wrapping around the ring roll prior to engagement. Similarly, heated or unheated tools may be used. Suitably the web is heated by wrapping around an RKA roll heated to 50-200 ° C or 50-100 ° C. The RKA roll and the ring roll may be driven at the same outermost surface speed, or there may be different speeds between the two rolls.

  The following figures show non-limiting examples of specific roll configurations and open web materials that can be formed thereby. These devices use a single nip (eg, because it is a simple mechanical process with only two engagement rolls), sometimes with higher processing speeds and possibly heating than prior art opening and stretching methods. It can be operated at low cost.

  3A and 3B show an exemplary apparatus 100 of the present invention that includes a pair of counter-rotating engagement 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 variation is referred to herein as a “convex raised RKA roll”. The second (lower) roll 104 of the apparatus 100 shown in FIGS. 3A and 3B is a ring roll.

  As shown in FIG. 4A, the first roll 102 includes a plurality of grooves 110 and ridges 120, and a plurality of staggered spaced apart teeth 130 that extend outward from the top surface 122 of the ridges 120. The configuration of the roll 104 is such that the upper surface 122 of the ridge 120 is positioned between the tip 134 of the tooth 130 and the lower surface 112 of the groove 110 relative to the axis A of the roll. As shown in FIG. 4B, the second roll 104 includes a plurality of grooves 140 and ridges 150. The groove 140 has a lower surface 142 and the raised portion 150 has an upper surface 152. Here, the distance between the upper surface 152 of the raised portion 150 and the lower surface 142 of the groove 140 is substantially the same around the circumference of the roll. FIG. 4C is another second roll 104B, in the form of a convex raised staggered CD SELF roll. The configuration of the roll 104B is such that the upper surface 122 of the ridge 120 is positioned between the tip 134 of the tooth 130 and the lower surface 112 of the groove 110 in the direction of the axis A of the roll. Returning to FIGS. 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 extend over at least some top surfaces 152 of the ridges 150 on the second roll 104. Engage to a greater depth.

  A suitable tooth for this process needs to contribute to the opening of the web. The teeth on the roll may have any suitable configuration. A given tooth may have the same plan length and width dimensions (such as a tooth having a circular or square plan view). Alternatively, a tooth may have a length that is greater than its width (such as a tooth having a rectangular plan view), in which case the tooth has any suitable aspect ratio of its length to its width. Can do. Suitable configurations for teeth include triangular side surfaces, square or rectangular side surfaces, cylindrical, pyramid shaped teeth, circular, oval, hourglass, star shaped, polygonal shaped teeth, and the like. However, it is not limited to these. Polygonal shapes include, but are not limited to, rectangles, triangles, pentagons, hexagons, or trapezoids. The tooth sidewall may taper at a constant angle from the base to the tip, or the angle may vary. The teeth may taper toward a point on the tooth tip, such as the tooth shown in FIG. 4A. The teeth can have a tip that forms a round, flat or pointed tip. Alternatively, the teeth may taper toward the tip of a multi-point elongated tooth, such as the SELF tooth shown in FIG. 4C. However, the tooth tip must form a pointed apex with at least one vertical wall of the tooth (e.g., a vertical wall at the front and rear ends of the tooth as shown in FIG. 4C); The teeth thus open or puncture the web. For the teeth shown in FIG. 4C, each tooth may form two openings, one at the front end and one at the rear end of each tooth.

In one exemplary embodiment shown in FIGS. 5A-F, the first roll 102 includes a plurality of pyramidal teeth 130 that extend outwardly from the top surface 122 of the ridge 120. FIG. 5A is a perspective view of a portion of the surface of another representative raised ridge RKA roll. 5B is a side view of the tooth arrangement shown in FIG. 5A, FIG. 5C is an end view, and FIG. 5D is a plan view. FIG. 5E is a cross-sectional view along line DD of the tooth arrangement shown in FIG. 5B. FIG. 5F is a cross-sectional view along the line EE of the tooth arrangement shown in FIG. 5B. Sectional area _{A t} of the tooth shown in Figure 5E, the cross-sectional area of the tooth _{A tb} smaller than shown in Figure 5F. The side surfaces (for example, 130a to 130f shown in FIG. 5E) are substantially triangular and taper at a constant angle from the distal end portion 134 to the base portion 132. The number of side surfaces may be 4 (eg, FIG. 4A), 6 (eg, FIGS. 5A-6C), or other 12 or fewer numbers. The teeth 130 are arranged in spaced circumferential rows with grooves 110 in between. The tooth | gear tip part space | interval SMD of _MD is 0.4 mm-15 mm (or 3 mm-8 mm). The pitch P of the CD is 0.4 mm to 10 mm (or 1 mm to 3 mm). The tooth has a depression angle α of 30 to 90 ° (or 45 to 65 °), a sidewall angle β of 3 to 15 ° on the long side surface of the tooth (for example, 130c and 130f), and an end surface depression angle γ of the front and rear ends of the tooth (For example, the angle between the side surfaces 130a and 130b or the angle between the side surfaces 130d and 130e) is 45 to 120 ° (or 60 to 90 °). In some cases, the tooth spacing of MD and CD, the staggered arrangement, and the end face depression angle γ are selected at the time of tooth preparation by helical grinding.

There are different ways to finish the portion 136 where the tooth 130 and the raised surface 122 contact, for example, cutting the taper on each side in a plane, a truncated (FIG. 6A), arcing the taper on at least one side And a semi-truncated (FIG. 6B), or a non-truncated (FIG. 6C) that does not cut the tapered portion of each side by any method. The tooth 130 shown in FIG. 6A tapers from the tip 134 toward the base 132 and has a truncated lower portion 136. Tapering and / or truncation may be performed to different degrees. The truncated portion of the tooth facilitates the manufacture of the tooth. In this case, referring to FIG. 7, the end face angle γ and ridges finish, by advancing the machining in the axial direction simultaneously the tool while rotating the tool in the circumferential direction D _C, single as is well known in manufacturing activities It can be realized by one helical processing step. The end faces of the teeth 130 will be manufactured according to a machining path M _P. Therefore, for the staggered tooth arrangement T _S , the end face depression angle γ is generated as 2 × inverse tangent (CD tooth pitch “P” / tooth stagger arrangement “T _S ”).

  The top surface 122 of the ridge between the teeth 130 may be finished in different ways. For example, the surface 122 may or may not be rounded. The rounded surface will protect the web from tearing during formation, particularly in the case of a film, but non-rounded surfaces (eg, surface 122 shown in FIGS. 6A-6C) may be less expensive.

The configuration of the raised ridge RKA roll 102 is such that the upper surface 122 of the ridge 120 is positioned between the tip 134 of the tooth 130 and the lower surface 112 of the groove 110 relative to the axis A of the roll 102. It is a thing. The tooth height _ht is defined as the distance between the tip 134 of the tooth 130 and the lower surface 112 of the groove 110. The height _{h t} of the teeth, 1mm~12mm, or 2 mm to 8 mm, or 3 mm to 6 mm. The height h _r of the ridge is at least 20%, typically 20% to 95% of the tooth height. The crosscut depth d _cc is defined as the distance between the tip 134 of the tooth 130 and the top surface 122 of the raised portion 120. In the present embodiment, the distance between the tip portion 134 of the tooth 130 and the upper surface 122 of the raised portion 120 is substantially the same around the circumference of the roll. The cross cut depth d _cc is determined by the amount of deformation necessary for forming the opening. For example, cross-cut depth _{d cc} is, 0.2Mm～9mm, or 1.0-4.0 mm, or 2.0mm~3.5mm may be in the range of. When the crosscut depth _dcc is small (with the same DOE), an opening having a large opening is produced. The engagement depth of the pair of rolls 102, 104 must be greater than the cross cut depth _dcc . Preferably, the engagement depth is at least 0.1 mm or 0.3 mm greater than the cross cut depth. The DOE at the nip N is 0.5 mm to 10 mm, or 3 mm to 7 mm, or 3 mm to 4 mm.

The height h _r of the raised portion is defined as the distance between the upper surface 122 of the raised portion 120 and the lower surface 112 of the groove 110. In some embodiments, as shown in FIGS. 3B and 4A, the first roll 102 has a transverse width, and the distance between the top surface 122 of the ridge 120 and the bottom surface 112 of the groove 110 is the roll 102. Substantially the same around the circumference and across the CD width. Alternatively, the distance between the upper surface of the first raised portion and the lower surface of the second groove may vary around the circumference of the first roll or across the CD width. Various alternative embodiments of convex raised rolls are possible. For example, as shown in the roll 162 in FIG. 8, the height h _r of the ridge, at least go may vary fleeting teeth 168. The height h _r of the ridge is determined by the amount of deformation required to form the desired openings. The top surface 166 of at least one ridge 164 between a pair of teeth 168 is at least 10%, 20%, or 30% greater than the height _hr2 of another ridge 164 between another pair of teeth 168. _Will have a height h _r1 . This roll 162 can be used in a process as shown in FIG. 3A in place of the convex raised RKA roll 102. The second roll may be a ring roll having raised portions with different heights either in the circumferential direction or in the axial direction.

  FIG. 9A is an example of a web 170 that can be produced by the apparatus shown in FIG. 3A, ie, an RKA convex raised roll having a staggered tooth pattern for the upper roll 102 and a ring roll for the lower roll 104. Indicates. The rolls 102 and 104 are aligned in the cross machine direction so that the teeth 130 on the first roll 102 are aligned with the grooves 140 on the second roll 104. When the teeth 130 on the first roll 102 penetrate the web 170, the ridges 150 on the second roll 104 can stretch the web 170 in the cross machine direction between the teeth 130 on the RKA convex raised roll 102. The raised portion 120 supports the web 170.

The web can be considered to be relatively flat in its initial state and composed entirely of non-open areas. Web 170 has a first surface 170A and a second surface 170B. When the web is fed to the nip N between rolls (eg, as shown in FIG. 3A) in the machine direction, the web is (i) opened by the teeth 130 of the first roll 102 and a plurality of spaced openings 172. (Ii) The opening 172 is stretched in the cross direction of the machine by being stretched by the raised portion 120 of the first roll 102. As shown in the top view of the web of FIG. 9A, the result is an open web 170 that includes an opening 172 and a land 174 that surrounds the opening 172. The opening 172 may be extruded in one direction (downward when viewed in FIG. 9A) from the plane of the web 160, and thus the opening 172 may have _a height Ha. Openings 172 are aligned in the MD and CD rows. FIG. 9B shows an enlarged plan view of a single opening 172. Opening 172 has a length L _a in the machine direction, and the width W _a in the cross machine direction. The opening preferably has an aspect ratio AR of length divided by width of 1-4, or 1.25-3, or 1.5-2.5, or 1.6-2.3. Let's go. Opening 172 further includes a respective opening area A _a, the perimeter P _a which surrounds the opening area, the. The open web includes 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 opening film has a tear strength (or tensile strength) in the transverse direction of the machine ranging from 1.5N to 5N, 2N to 4N, 2.5N to 4N, 2.5N to 3.5N, or 2.7N to 3.9N. ) (Per 25.4 mm). The open nonwoven fabric has a tensile strength (per 25.4 mm) in the cross machine direction in the range of 2N to 20N or more. In one embodiment, the web has a machine direction orientation and a cross machine direction orientation, the opening has a length in the machine direction and a width in the cross machine direction, and the plurality of openings are long. The aspect ratio obtained by dividing the width by the width is 1 to 4.

  In some embodiments, the stretching process described above not only increases the CD width of the opening, but also creates alternating ridges and grooves where the openings are located in the grooves. The portion of the web in contact with the ridges on the two rolls is not stretched frictionally at the top of the ridge, but the web between the ridges is stretched from the plane. The portion of the web that extends from the plane has a greater orientation in the z direction. As a result, a web having ridges and grooves in which the openings are located in the grooves can be formed. Note that if the web is turned upside down, the groove will become a ridge, the ridge will become a groove, and the opening will now be located in the ridge. The fibers at the top of the ridge and the fibers at the bottom of the groove can be more oriented in the XY plane than the fibers at the sidewall.

  In the case of film, in the stretch region, the web becomes thin and the basis weight is reduced, whereas in the region of the web that is frictionally locked by the ridges of the roll, the web thickness and basis weight are maintained. This results in a web where alternating thick and small areas, alternating large and small basis weight areas, and a large and large basis weight area at the top of the ridge and The region having a small thickness and a small basis weight located at the bottom of the groove is located on the intermediate side wall. FIG. 11 is a plan view of a 25 gsm PE film web 210 (the film has been stretched / flattened to show a high basis weight region 212 and a low basis weight region 214). The web 210 further shows ridges R, grooves G, and sidewalls S. The opening 216 exists in the groove G. As can be seen, the high basis weight region 212 is located in the ridge R and the groove G, while the low basis weight region 214 is located in the sidewall S.

  In the case of non-woven fabric, the basis weight decreases in the stretched region, and similarly, a web in which regions having a large basis weight and regions having a small basis weight are alternately formed is located, and the region having a large basis weight is located at the top of the raised portion and the bottom of the groove. The region with a small basis weight is located on the middle side wall. FIG. 12 is a plan view of a 60 gsm polypropylene nonwoven web 220 (the nonwoven is stretched / flattened to show a high basis weight region 222 and a low basis weight region 224). Web 220 further shows ridges R, grooves G, and sidewalls S. The opening 226 exists in the groove G. Thermal bond or fusion points 228 may exist at various locations on the web 220. As can be seen, the high basis weight region 222 is located in the ridge R and the groove G, while the low basis weight region 224 is located in the sidewall S. In the case of nonwovens, the web thickness may not decrease in the stretch region because the fibers can unwind and move away from each other. However, the thickness of some individual fibers may decrease as a result of stretching. Note that the “region” of the web used to indicate the basis weight feature excludes the opening itself.

  As a result of stretching, the web is permanently stretched in the direction of stretching. If the web remains in its corrugated state, most of the increased web width is taken up by the ridges and grooves formed in the web. Alternatively, tension may be applied to widen the web, resulting in a decrease in the height and frequency of the ridges and grooves and a decrease in the overall basis weight of the web. If desired, the web may be spread out so that the ridges and grooves are no longer present, and the web returns to its flat state. This deformation process allows the web to stretch or stretch to 10%, 15%, 20%, 25%, or more on CD. The amount of permanent elongation and the degree of ridge and groove formation depends on the tool geometry, process conditions, and material properties. Typically, this process will permanently stretch or stretch the nonwoven web material further than the film material. For example, the web can extend 165 mm to 190 mm on a CD. Preferably, the web has an initial web basis weight area and a low basis weight area having a lower basis weight than the initial web basis weight.

13 is a cross-sectional view of the web 220 shown in FIG. 12, showing the ridge R, groove G, and axis X pulled horizontally through the cross-section of the web, with the top of the ridge above the X-axis. The lower region is hollow, i.e. contains the hollow region HA. Similarly, the region below the X axis and above the bottom of the groove is hollow, that is, includes a hollow region HA. Preferably, 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 sidewall. Similar means that the thicknesses are within about 60% of each other. Alternatively, the web thickness at the top of the ridge and the web thickness at the bottom of the groove is greater than the web thickness at the sidewall. FIG. 14 is a side perspective view of another nonwoven web 230 having ridges 232, grooves 234, and sidewalls 236. FIG. 15 is a top perspective view of a 28 gsm polyethylene / polypropylene composite (bico) nonwoven web 240 that includes a ridge 242, a groove 244, and an opening 246, where the opening width W _a is greater than the ridge width W _r. . FIG. 16 is a cross-sectional view of the film web 250 showing that the wall thickness reduction at the side wall 256 is greater than the top of the ridge 252 or the bottom of the groove 254.

  The targeted process herein can also use multiple deformation steps to more gently deform the material or to impart a greater amount of permanent deformation. Such multiple deformation steps may be performed by any suitable apparatus described in US patent application Ser. No. 13 / 094,195 (Lake et al.). Preferably, at least the first roll or the second roll forms a nip with one or more additional rolls, thereby further stretching or deforming the web. In one arrangement 200 as shown in FIG. 10, the ring roll 202 is in mesh with a convex raised roll 204, which then protrudes into another ring roll 206 so that the roll is in a planetary or satellite configuration. Is engaged. Processes that use multiple deformation steps include hybrid, closed loop, and common, with nested devices having a relatively small number of rolls in a nested configuration, or any suitable number of rolls to implement the desired deformation It may be implemented in a device such as a bank.

  Many alternative embodiments of open web materials and processes for making them are possible. For example, a web material having different regions (such as deformed regions and / or undeformed regions) with different characteristics across its surface may be supplied. The region may be due to at least one feature selected from the group consisting of ridge height, ridge spacing, opening dimensions, fiber diameter, film thickness, or combinations thereof. In one embodiment, an open web material may be provided having areas of openings, and optionally having areas of ridges and grooves. The webs disclosed herein may include regions having different sized openings and / or ridges and grooves of different sizes and frequencies. The web can include one or more layers. In other embodiments, the film is a microtextured film that includes stretched and non-stretched regions, where the stretched regions have different microtextured properties than the non-stretched regions, wherein the microtextured properties include open area, dimension , Orientation, and combinations thereof. Webs produced by the processes and apparatus described herein may include ridges that run discontinuously over the deformation region, or ridges that run continuously over the deformation region. In order to make such an open web material, the ring roll used may include ridges and groove areas. Alternatively, the ring roll may have regions with different ridge heights, thereby producing different engagement depths (DOEs) and different depths under the convex ridges, and thus different widths and An opening having an opening area is produced. Alternatively, or in addition, the convex ridge roll may include different regions, where the ridges have different heights.

Example 1
In one non-limiting example for creating openings in a polymer film such as web 300 shown in FIG. 17 (including micro openings 312 and macro openings 314), an engagement depth of 3.8 mm Now a device with a 1.5 mm pitch convex raised RKA roll that engages a 1.5 mm pitch ring roll can be used. The convex raised RKA roll has teeth oriented so that the longitudinal direction is MD. The teeth are arranged in a staggered pattern as shown in FIG. 5A. Teeth, has a pyramidal shape with six sides tapering toward previously pointed from the base of the tip portion has a height h _t of 4.7 mm. The tooth has a depression angle (α in FIG. 5B) of 62 °, a sidewall angle (β in FIG. 5C) on the long side of the tooth is about 6 °, and an end surface depression angle (γ in FIG. 5E) is 90 °. The ridges extending between the teeth on the RKA roll are not formed with rounds and form a flat surface. The teeth are semi-truncated at the ridges as shown in FIG. 6B. The ridges and grooves extend circumferentially around the ring roll.

There are two different tooth sections on the roll, which are presented to demonstrate the benefits of convex ridges, referred to as "section A" and "section B", respectively. In section A, the tip interval SMD of _MD teeth is 4.9 mm, the crosscut depth (d _{cc in} FIG. 6A) is 3.6 mm, and the height of the raised portion (h _{R in} FIG. 6A) is 1. 1 mm. Category B is, 3.7 mm tip portion spacing _{S MD} tooth MD, cross-cut depth _{d cc} is 2.7 mm, ridge height _{h r} obtained is 2.0 mm.

  The counter ring roll has a pitch of 1.5 mm, a height of 4.8 mm, a tip radius of 0.12 mm, and a side wall angle of about 4 °. Both rolls have a diameter of about 205 mm and are heated to 80 ° C. The RKA roll and ring roll are aligned with the CD so that the gaps on either side of the tooth are approximately equal.

The precursor web is a 26 g / m ² basis weight micro-open polymer film with a blend of LLDPE and LDPE obtained from RKW-Group (Germany). LLDPE comprises about 60% film composition, about 30% LDPE, and the remaining 10% of inert components and fillers such as TiO ₂ and their carrier resins. The micro-openings are 21.7 mesh (openings per centimeter in the orthogonal direction (55 mesh (openings per inch in the orthogonal direction))) and equilateral triangles with a center spacing of about 462 micrometers Arranged in the pattern. The diameter of the opening is 175 to 200 micrometers, and the height of the tapered cone is about 120 micrometers.

  The precursor web is pre-wound onto the ring roll before passing between the engagement rolls at a linear web speed of 480 meters / minute. The micro-opening cone side of the film is placed facing the RKA roll. Use an engagement depth of 3.8 mm. The resulting film is shown at low magnification in FIGS. 18A and 18B. The film opening area (% of film area with open opening), opening length, and opening width can be purchased from the vision system (eg, Cognex Corporation (Natik, Mass.) Under the trade name IN-SIGN. ) Is measured. A comparison of the opening area, length, and width of the opening of Section A (FIG. 18A) versus Section B (FIG. 18B) is shown in the following table. 18A and 18B show a film web 320, 340 having micro openings 322, 342 and openings 324, 344. FIG.

(Example 2)
In one non-limiting example for creating a corrugated web with openings in the grooves, a 2.0 mm pitch convex ridge that engages a 2.0 mm pitch ring roll with an engagement depth of 6.3 mm. An apparatus with an RKA roll can be used. The convex raised RKA roll has teeth oriented so that the longitudinal direction is MD, and the raised portions and grooves extend circumferentially around the ring roll. The teeth are arranged in a staggered pattern as shown in FIG. 5A. Tooth has a pyramid shape with four sides tapering toward previously pointed from the base of the tip portion has a height h _t of 6.9 mm. The teeth have a depression angle (α in FIG. 5B) of 57 ° and a sidewall angle (β in FIG. 5C) on the long side of the tooth is about 5 °. The ridges between the teeth on the RKA roll are not rounded and form a plane. The teeth are finished non-truncated at the ridges as shown in FIG. 6C. Teeth, 8.0 mm tip portion spacing _{S MD} tooth MD, cross cut depth _{(d cc} in FIG. 6A) is 3.7 mm, the resulting ridge height _{(h R} in FIG. 6A) is 3.2mm It is.

  The counter ring roll has a pitch of 2.0 mm, a height of 6.9 mm, a tip radius of 0.12 mm, and a side wall angle of about 4 °. Both rolls have a diameter of about 142 mm. The RKA roll and ring roll are aligned with the CD so that the gaps on either side of the tooth are approximately equal.

The first precursor web is available from Clopa Plastics Co. It is a polymer film with a basis weight of 25 g / m ² of a blend of LLDPE and LDPE obtained from (Ohio). The precursor web is pre-wound onto the ring roll before passing between the engagement rolls at a line web speed of 20 meters / minute. The resulting corrugated aperture film is shown in FIG. 11 (the film is stretched / flattened to show high and low basis weight regions). The images were taken at low magnification using a red LED backlight and using an optical microscope (eg, commercially available from Allasso Industries).

The second precursor web is a 60 g / m ² basis weight heat bonded polypropylene nonwoven fabric obtained from Fiberweb (France). The precursor web is pre-wound onto the ring roll before passing between the engagement rolls at a line web speed of 20 meters / minute. The resulting corrugated open nonwoven is shown in FIG. 12 (plan view, web is stretched / flattened to show high and low basis weight regions), FIG. 13 (cross-sectional view), FIG. 19A (convex ridge RKA). Side) and FIG. 19B (ring roll side). Images were taken at low magnification using an optical microscope (eg, commercially available from Allasso Industries). The web 400 of FIGS. 19A and 19B includes alternating ridges 402 and grooves 404, with openings 406 in the grooves 404.

  The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Rather, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” shall mean “about 40 mm”. Furthermore, the numerical ranges recited herein include any other narrower range within the range, in addition to each distinct numerical value. All maximum numerical limits given throughout this specification are intended to encompass lower numerical limits as if such lower numerical limits were explicitly set forth herein. Should be understood. All minimum numerical limits described throughout this specification include all higher numerical limits as if such higher numerical limits were expressly set forth herein. All numerical ranges described throughout this specification are all narrower within such wider numerical ranges as if such narrower numerical ranges were expressly set forth herein. Includes numerical range.

  All references cited in “Best Mode for Carrying Out the Invention” of the present invention are hereby incorporated by reference in the relevant part, and any citation of any reference is prior art to the present invention. Should not be construed as tolerating. To the extent that any meaning or definition of a term in this document contradicts any meaning or definition of a term in a document incorporated by reference, the meaning or definition given to that term in this document applies. Shall be.

  While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, all such changes and modifications that are within the scope of this invention are intended to be covered by the appended claims.

Claims (8)

An apparatus comprising two engaging counter rotating rolls forming a nip between the rolls, the apparatus comprising:
a) a substantially cylindrical first roll, wherein the first roll has a surface, a circumferential portion, and a shaft;
A plurality of circumferential first ridges and circumferential first grooves on the surface of the roll, wherein the first ridge has an upper surface and the first groove has a lower surface. A first ridge in the circumferential direction and a first groove in the circumferential direction;
A plurality of spaced teeth extending outwardly from the upper surface of the first raised portion, each tooth tapering from the upper surface to a tip portion, and the upper surface of the first raised portion is the tooth of the tooth A first roll including a plurality of spaced teeth positioned between a tip and the lower surface of the first groove;
b) a second roll of substantially cylindrical, said comprising second roll of the second ridge and a second groove in the plurality of continuous circumferential, seen containing a second roll, and
The height of the teeth is from 1 mm to 12 mm;
The first roll includes a cross-cut depth measured from the top surface of the first raised portion to the tip of the tooth, and the nip has an engagement depth between the first roll and the second roll; The engagement depth is greater than the cross-cut depth,
The apparatus, wherein the first ridge has a predetermined height and the height is at least 20% of the height of the tooth . Includes a depth of engagement between the nip between the said first roll second roll, wherein the engagement depth of 3 mm to 4 mm, according to claim 1. The first roll includes a transverse width, and the distance between the upper surface of the first raised portion and the lower surface of the first groove is substantially around the circumference of the first roll and across the transverse width. The device according to claim 1 or 2 , wherein the same. The first roll includes a transverse width, and a distance between the upper surface of the first raised portion and the lower surface of the first groove is different around the circumference of the first roll or across the transverse width. The apparatus according to claim 1 or 2 . The tooth and the surface is engraved, comprising at least four or six sides, according to any one of claims 1 to 4. The teeth and portions ridges surfaces are in contact, truncated, half-cut head, non-truncated, and are finished to provide a shape selected from the group consisting of any of claims 1-5 A device according to claim 1. Wherein said top surface of first ridges, rounded shape, non-rounded shape, or is selected from the group consisting of A device according to any one of claims 1-6. The apparatus according to any one of claims 1 to 7 , wherein the second roll is a ring roll having raised portions having different heights in either the circumferential direction or the axial direction.

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