CN1297243C - Methods of bonding materials, especially materials used in absorbent articles - Google Patents

Abstract

Methods of bonding materials used in the manufacture of articles, including, but not limited to, absorbent articles such as sanitary napkins, pantiliners, tampons, absorbent interlabial devices, diapers, incontinence devices, wipes, and the like are disclosed. There are numerous aspects of the disclosed methods. In one aspect, the method involves bonding through incompatible materials during the process of making a composite structure comprising several materials. In another aspect, improvements are made that allow the method to be used to bond through relatively thick materials (e.g., materials having a thickness of greater than or equal to about 4 mm). In another aspect, the methods are provided with the ability to create a virtually unlimited number of bonding patterns in the materials to be bonded. In still another aspect, the methods of bonding utilize a compression step to improve bond formation. In still another aspect, methods of bonding that utilize a step of slitting a material through which the bonds are made are disclosed.

Description

Materials, especially methods of joining materials used in absorbent articles

The applicant is Procter & Gamble, the application date is November 25, 1998, the application number is 98813318.0, and the name is a divisional application of the invention of the method of joining materials, especially materials used in hygroscopic products.

Field of Invention

The present invention generally relates to methods of joining materials used in absorbent articles, although the methods described herein may be used to join materials used in other forms of articles. In a preferred embodiment, the present invention relates to a process for making absorbent articles such as sanitary napkins, pantiliners, tampons, absorbent interlabial articles, diapers, incontinence articles and the like.

Background technique

Absorbent products, such as sanitary napkins, panty liners, tampons, interlabial absorbent products, disposable diapers, incontinence products, and bandages, are designed to absorb and retain fluids and other exudates from the body and to prevent soiling body and clothing.

In manufacturing absorbent articles, it is generally necessary to join together the component parts forming the absorbent article in order to form the final product. Common methods of joining such materials include the use of adhesives, heat and/or pressure, and ultrasound.

However, certain materials cannot be joined using these general joining methods due to their structural integrity or composition. For example, U.S. Patent No. 5,260,345 issued to Des Marais et al. on November 9, 1993, U.S. Patent No. 5,268,224 issued to Des Marais et al. on December 7, 1993, and U.S. Patent No. 5,268,224 issued to Dyer et al. on February 7, 1995 Absorbent foam made from a high internal phase emulsion (or "HIPE" foam) described in No. 5,387,207 is one such form of material. Generally, such materials have low tensile strength and/or poor structural integrity. Adhesives are difficult to join such materials because the structural integrity of the material is not as strong as that of an adhesive joint. As a result, only a portion of the material that is in direct contact with the adhesive can be bonded to other materials. The rest of the material is easily separated from the bonded material. Because this foam is a heat-set polymer, it cannot be joined by thermal joining. Once this material is made, it cannot be remelted. Conversely, when heat is applied to such a foam material, the material chars instead of melting and flowing as desired for thermal bonding. Since such heat-set foams cannot flow and melt under pressure, pressure cannot be used to join such foams.

U.S. Patent No. 4,473,611, issued September 25, 1984 to Haq, entitled "Porous Polymer Material Containing Reinforcing and Heat Sealing Material," describes a previous method of polymerizing a material with a high internal phase emulsion. A method of bonding porous polymeric materials. The materials described in the Haq literature can be heat-sealed by adding thermoplastic fibrous, granular or porous materials. For example, articles such as wipes can be obtained by sandwiching the improved porous polymer material between two heat-sealed substrates, and then connecting the first and second substrates with the porous polymer material in the middle. Heat-sealable reinforcements are heat-sealed. However, the method of making porous polymeric materials described in the Haq patent requires the addition of thermoplastic materials. This complicates the process of making the porous polymer material.

Other forms of materials used in the manufacture of absorbent articles generally include thermoplastic materials. U.S. Patent No. 4,854,984, entitled "Dynamic Mechanical Splicing Method and Apparatus," issued August 8, 1989 to Ball et al. discloses a method for feeding a plurality of sheets through a pressurized offset gap between two rollers. , and a method and apparatus for dynamically mechanically joining multiple sheets together. At least one of the two rollers has a concavo-convex pattern. The method described in the Ball et al. patent has been used commercially with great success. However, the search continues for improved methods of joining materials.

Accordingly, there remains a need to find ways to improve joining materials, particularly materials used in absorbent articles. For example, there is a need for an improved method of joining materials used in absorbent articles that cannot be joined by known joining methods; in particular, one that does not require the addition of thermoplastic materials to the material in question in order to join other materials Methods. Additionally, there is a need to find ways to join thicker materials during the manufacture of absorbent articles. In addition, there is a need for a joining method capable of forming a practically infinite number of joining patterns in materials to be joined.

Contents of the invention

Although the methods described herein may also be used to join materials used in other forms of articles, the present invention generally seeks to provide various methods of joining materials used in absorbent articles. All such uses of the methods described herein are considered to be within the scope of the present invention. In a preferred embodiment, the present invention relates to a process for making absorbent articles such as sanitary napkins, pantiliners, tampons, interlabial absorbent articles, diapers, incontinence articles and the like.

The invention has many aspects. One aspect of the invention relates to a method of joining incompatible materials during the manufacture of a composite structure comprising several materials. As used herein, the term "incompatible material" refers to a material that is difficult to bond to other materials by conventional bonding methods. Another aspect of the invention relates to an improved method of joining thicker materials, for example materials having a thickness greater than or equal to about 2, 3 or 4 mm. Yet another aspect of the invention relates to a joining method that can form a virtually infinite number of joining patterns in the materials to be joined. Another aspect of the invention relates to a joining method that employs a compression step to improve the joint. Yet another aspect of the invention relates to a method of joining by employing the step of cutting through the material forming the joint through.

It should be understood that in order not to make the description unduly long, the embodiments described in the description are presented in terms of preferred embodiments. It should also be understood that the present invention is not limited to these examples. It should also be understood that various aspects of the methods described herein can be combined in a single process; or can be used alone; or combined in any desired manner. It should also be understood that all such uses of the invention or combinations of aspects of the invention contemplated by the inventors may constitute separate potentially patentable inventions which, therefore, will be as broad in scope as the prior art. The scope of these inventions is limited only by the claims, not by the preferred embodiments described herein.

The present invention provides a method of making a composite web of formed tubes of absorbent material for use in absorbent articles, the method comprising the steps of: (a) providing a web of absorbent material having a first surface and an opposite second surface; (b) providing a covering material for said web of absorbent material; (c) at least partially covering said first and second surfaces of said web of absorbent material with said covering material to form a covered (d) forming said covered absorbent material web into an unformed absorbent material tube; (e) forming a portion of said covering material covering said absorbent material web first surface Self-bonded to a portion of the cover material that covers the opposite portion of the second surface of the web of absorbent material while displacing the web of absorbent material in the bonded region to form at least one seam, forming a shaped Composite web for tubes of absorbent material.

The method of joining incompatible materials preferably includes the following steps:

(a) providing materials that are at least to some extent incompatible using conventional methods, the incompatible materials having a first bonding capability, a first surface and a second surface;

(b) providing at least one other material having a higher bonding ability than the first bonding ability;

(c) covering at least a portion of the first and second surfaces of the incompatible materials with the at least one material having a higher bonding capacity than the first bonding capacity; and

(d) using a joint that penetrates said incompatible material, a material with higher bonding ability covering at least a portion of said first surface of said incompatible material and a material covering said incompatible material At least a portion of the second surface is bonded to a material having a high bondability.

According to this aspect of the methods described herein, the incompatible material preferably comprises a hygroscopic material. In a preferred embodiment, the incompatible material is a heat-set polymeric absorbent foam material. The higher bondability material may comprise a number of suitable materials including, but not limited to, one or more webs of material, glue layers or silicone coatings. In a preferred embodiment where the incompatible material is a heatset polymeric absorbent foam material, the higher bonding capacity material is a nonwoven web.

The present invention also provides a method of forming a material, particularly a compressible material, for example for use in absorbent articles such as sanitary napkins, panty liners, tampons, interlabial absorbent articles, diapers, incontinence articles, wipes, etc. hygroscopic material. According to this aspect of the method of the present invention, the compressible incompatible material is embossed with a joining pattern, isolating a portion of the incompatible material from the remainder thereof, and forming the isolated portion into a unique shape. Forming in the methods described herein may include one or more folding steps. Many other applications of the methods described here will also be appreciated.

Description of drawings

Although there are claims at the end of the specification that specifically point out the subject matter of the present invention and clearly set forth the claims, the present invention can be better understood through the following description in conjunction with the accompanying drawings. in:

Figure 1 is a perspective view of a composite web of material comprising incompatible absorbent foam materials joined and formed into a sanitary napkin absorbent tube using the method of the present invention;

Figure 2 is a perspective view of an apparatus for making the absorbent material in the form of a composite web shown in Figure 1 into a granular material using an optional, but preferred, step of making an absorbent tube;

Fig. 3 is a fragmentary perspective view of the composite web shown in Fig. 1 after being fed into the apparatus shown in Fig. 2 and after the incompatible absorbent foam material has been made into granular material;

Figure 4 is a perspective view of the composite web shown in Figure 3 after the side margins have been folded in a first selective folding step;

Figure 5 is a schematic perspective view of the composite web shown in Figure 3 after being folded in a second selective folding step;

Figure 6 is a schematic perspective view of the composite web shown in Figure 5 after the parts have been joined together;

Figure 7 is a simplified cross-sectional view of the composite web shown in Figure 6 taken through a junction along line 7-7 of Figure 6;

Figure 8 is a schematic perspective view of one embodiment of the step of the method for joining the tube of absorbent material of the sanitary napkin, wherein the embossing roller is shown in simplified form;

Figure 9 is a simplified partial schematic diagram showing a thicker material thickness in the gap between an embossing roll and an anvil roll, wherein there is no compressible material around the raised members of the embossing roll;

Figure 10 is a simplified partial schematic view showing a greater thickness of material in the gap between an embossing roll and an anvil roll, wherein there is compressible material around a raised member of the embossing roll;

Figure 11 is a perspective view showing the surface of a conventional dynamically engaging roller with intermittent load bearings;

Figure 12 is a perspective view of the surface of an embossing roll with a continuous load support used in one embodiment of the method of the present invention;

Figure 13 is a perspective view of a compound sanitary napkin on the body-facing side having a tube of absorbent material joined and formed using the method of the present invention;

Figure 14 is a schematic diagram showing another method of bonding two incompatible materials together using the method of the present invention;

Figure 15 is a perspective view of an absorbent interlabial article joined and formed using the method of the present invention;

Figure 16 is a perspective view of a variation of the method of the present invention for making an interlabial absorbent article;

Figure 17 is a partial plan view of a sanitary napkin manufactured by the method of the present invention;

Fig. 18 is a schematic cross-sectional view of a portion of the sanitary napkin shown in Fig. 17 .

Detailed ways

Although the methods described herein can be used to join materials used in other forms of articles, the present invention relates to a method of joining materials used in absorbent articles. Preferred embodiments of the present invention relate to methods for making absorbent articles such as sanitary napkins, panty liners, tampons, interlabial absorbent articles, diapers, incontinence articles, wipes, and the like.

The invention has many aspects. One aspect of the invention relates to a method of joining incompatible materials during the manufacture of a composite structure comprising several materials. As used herein, the term "incompatible material" refers to a material that is difficult to bond to other materials by conventional bonding methods. Another aspect of the invention relates to an improved method of joining thicker materials, for example materials having a thickness greater than or equal to about 2, 3 or 4 mm. Yet another aspect of the invention relates to a joining method that can form a virtually infinite number of joining patterns in the materials to be joined. Another aspect of the invention relates to a joining method that employs a compression step to improve the joint. Yet another aspect of the invention relates to a method of joining by employing the step of cutting through the material forming the joint through.

It should be understood that in order not to make the description unduly long, the embodiments described in the description are presented in terms of preferred embodiments. It should also be understood that the present invention is not limited to these examples. It should also be understood that various aspects of the methods described herein can be combined in a single process; or can be used alone; or combined in any desired manner. It should also be understood that all such uses of the invention or combinations of aspects of the invention contemplated by the inventors may constitute separate potentially patentable inventions which, therefore, will be as broad in scope as the prior art. The scope of these inventions is limited only by the claims, not by the preferred embodiments described herein.

In particularly preferred embodiments, absorbent articles (or other forms of articles), or portions of absorbent articles, may be formed using the methods of joining materials described herein. By using joining methods, external forces are applied to parts of the article to form the article, and the article has a unique three-dimensional shape.

1. DESCRIPTION OF A NON-LIMITING EMBODIMENT OF THE PROCESS OF THE INVENTION FOR MANUFACTURING A TUBE OF ABSORBENT MATERIAL FOR A COMPOSITE SANITARY NAPPLICATION

The method of the present invention can be used to join many different materials used in many different forms of articles, including absorbent articles. Figures 1-8 illustrate a preferred application of the method of the invention. Figures 1-8 illustrate a method for manufacturing a tube of absorbent material placed on the body-facing side of a base pad constituting a compound sanitary napkin. Combination sanitary napkins consist of a main menstrual pad (tube of absorbent material) connected to a panty protector (base pad). Tubes of absorbent material are joined and formed using the method of the present invention. The final product is shown in Figure 13.

The figures show the many steps to be carried out before (and after) the step of joining the material comprising the tube of hygroscopic material. It should be understood that these steps are optional and are shown here because they are useful in making the absorbent product shown in FIG. In all cases where the methods of the invention are used, these optional steps need not be included. It should also be understood that the method of the present invention is not limited to the method shown in FIG. 1-FIG. 8, and the method shown in FIG. 1-FIG. 8 is just an example.

A. Assembly of components

Figure 1 shows a composite web joined and formed into a material 20 for an absorbent tube in the sanitary napkin shown in Figure 13 using the method of the present invention. The composite web of material 20 shown in FIG. 1 includes a first material, such as the first web of material 22, that is incompatible with joining using conventional methods such as adhesives, heat and/or pressure, and ultrasound. . Accordingly, the first web of material 22 may also be referred to as "bonded incompatible material" or "web of incompatible material." The web of incompatible material 22 has a first surface 22A and a second surface 22B.

The incompatible first material 22 may be any suitable material. Preferably, the web of incompatible material 22 is a hygroscopic material, although substantially non-hygroscopic incompatible materials can be joined using the method of the present invention. The web of incompatible material 22 can be, but need not be, compressible and/or elastic. Preferably, according to this aspect of the invention, the first material 22 is a compressible and resilient porous absorbent material. Nor is the first material limited to materials in web form. The first material 22 may have any suitable form. For example, the first material 22 may be in the form of a mass of particles or fibers, a laminate, one or more layers, a ribbon, a sheet, a block, or a web. For making the tube of absorbent material shown in the drawings, the first material 22 is preferably in the form of a web.

The web of incompatible material 22 has a first bondability (the ease or degree to which other materials bond or readily bond to it). The web of incompatible material 22 may, but need not be, be completely incompatible with conventional joining methods. For example, a web of incompatible material may be one material to which the other material is not easily bonded using these methods. A material's ability to join can be determined by measuring the force required to separate a material from a joint, or to join another material. According to this definition, under the action of the force that will cause the two materials to peel apart or the force required to destroy the structural integrity of the incompatible material in the process of trying to separate the materials (whichever occurs first), the material will separate.

A web of incompatible material 22 may be a material to which other materials do not readily bond for one or more reasons. Often, such materials are incompatible with conventional joining methods because of their structural integrity or compositional relationships. Cellular polymeric absorbent foams made from high internal phase emulsions (or "HIPE" foams) are one type of such incompatible materials. Absorbent foams having these characteristics are described in the patent literature including, but not limited to, the following patents: U.S. Patent No. 5,260,345, issued November 9, 1993 to DesMarais et al., issued December 7, 1993 to DesMarais et al. US Patent No. 5,268,224, and US Patent No. 5,387,207 issued February 7, 1995 to Dyer et al. Such materials have low tensile strength, and/or poor structural integrity, and/or low elongation before failure.

Because the structural integrity of the material is not as strong as the bond, it is difficult to use adhesives to join other materials to the absorbent foam. As a result, only the portions of the incompatible material that are in direct contact with the adhesive are able to bond with other materials. The rest of the incompatible material is easily separated from the material it joins. Additionally, because the foams described in the aforementioned patents are heat-set polymers, these foams cannot be thermally bonded to other materials. Once these materials are made, they cannot be remelted. Instead, when heat is applied to these foam materials, the materials char rather than melt and flow as required for thermal bonding. Additionally, since heat set foams cannot flow and melt under pressure, these foams cannot be joined by pressure.

Thus, a web of incompatible material 22 is also referred to as a material that does not readily join. In some cases, it may also be referred to as a material that is not heat-sealable, has no thermoplasticity; and/or has poor structural integrity. It should also be understood that the use of incompatible materials is only important in the aspect of the invention involving joining methods of incompatible materials. In other aspects of the methods described herein, it is not necessary to use incompatible materials. In these other aspects described, any suitable material may be used, including a wide variety of hygroscopic materials.

In the embodiment shown in the figures, the web of incompatible material 22 is a web of hygroscopic foam material, such as one of the foam materials described in the aforementioned patent. The web of incompatible material 22 in the embodiment shown in FIG. 1 is at least partially wrapped around a second web of material 24 . The second web of material 24 has a second bondability higher than the bondability of the web of incompatible material 22 . That is: the material can be more easily joined to other materials (or to the material itself) using common joining methods. The second web of material 24 may also be referred to as a "carrier web" or a "bondable web." In the embodiment shown in FIG. 1, it is preferable to completely wrap the second web of material 24 around the web of incompatible material 22 such that the cross-section of the second web of material 24 is folded in an "e" shape. shape.

The second web of material 24 can be any material that can be bonded to itself, or to at least some of the other materials used in the various forms of absorbent articles described herein, using heat or pressure, adhesives, or ultrasonic waves. . The second web of material 24 can be made from a variety of different materials, such as: woven and nonwoven materials; formed thermoplastic films such as apertured, apertured or non-apertured plastic films, and hydroformed thermoplastic films polymeric materials such as; cellular foams, reticulated foams; reticulated thermoplastic films; and thermoplastic scrims. Suitable woven and nonwoven materials may be composed of natural fibers (e.g., wood fibers or cotton fibers), synthetic fibers (e.g., polymer fibers such as polyester, polypropylene or polyethylene fibers), bicomponent fibers (e.g., The core is one material, and the outer shell is the fibers of another material), or a combination of natural fibers and synthetic fibers. Preferably, in the illustrated embodiment, the second web of material 24 comprises at least in part a thermoplastic material. However, in other embodiments, the second web of material 24 need not include a thermoplastic material, particularly if adhesives or other forms of joining methods are used. For example, the second web of material 24 may be a cellulosic material capable of hydrogen bonding to itself.

In yet another embodiment, the second web of material 24 may be replaced with a material other than the web form of the material. For example, the second web of material 24 may be replaced with a bondable layer; or a coating such as an extruded glue layer, or a polymeric coating applied to the web of incompatible material 22 . Glues, especially hot melt adhesives, are similar to thermoplastic materials in that they can be joined using this aspect of the method of the invention. Certain silicones, especially those with a very low melting point, are also capable of bonding as described above. For this reason, the second web of material 24 may be referred to as a "second material," so that it is clear that the material includes materials that are not webs.

In the preferred embodiment shown, the second material 24 preferably comprises a material suitable for use as a wrapper for the absorbent material of the absorbent article. For example, the second material 24 may serve as a containment web for the absorbent material of the absorbent article, a cover or topsheet for the absorbent article, or a backsheet for the absorbent article. For the embodiments shown in Figures 1-8 and 13, the second material 24 comprises a containment web made of a spunbond nonwoven material. A particularly preferred spunbond nonwoven material is Fiberweb, North America of Washougal, WA company sold d's No. 0.65MLPV60U (or "P-9") product of 19 ^grams per ^yard Spunbond polypropylene nonwoven material. Another particularly preferred nonwoven material is a spunbonded polyethylene nonwoven material sold under the name COROLIND by Corovin GmbH, Peine, Germany, which is available in two basis weights: 23 gsm and 30 gsm.

Although the second web of material 24 is wrapped in an e-folded shape around the web of incompatible material 22, it should be understood that if a web material is used, the second web of material 24 is not limited to The web of incompatible material 22 is wrapped in an e-shape. The relationship between the web of incompatible material 22 and the second web of material 24 is preferably such that webs of material having a higher bonding ability than the web of incompatible material 22 are only at least adjacent to the incompatible material 22. Two opposing surfaces of the web (eg, 22A and 22B shown in FIG. 1 ). Thus, in other embodiments, the second web of material 24 may only be partially folded, or partially wrapped around the web of incompatible material 22 . The second web of material 24 may be folded or wrapped around incompatible material 22 in any suitable shape. Other suitable shapes include, but are not limited to, folded into a C-shape and the like.

Additionally, the second web of material 24 is not necessarily limited to a single web encasing the web of incompatible material 22 . A web of one or more materials may be placed proximate to each surface 22A and 22B of the web of incompatible material 22 . For example, in other embodiments there may be two separate webs of the second material 24 with one web proximate to each surface 22A and 22B of the web of incompatible material 22 . The two webs of second material 24 may be the same form of material and have the same properties. In other embodiments, the two webs of material near each surface 22A and 22B of the web of incompatible material 22 may be different. For example, the two webs may be of different types of material, or of the same basic type of material but with different characteristics (eg, thickness, etc.).

In yet another embodiment, the web of second material 24 need not be as wide or as long as the web of incompatible material 22 . For example, the second material 24 may be in the form of ribbons, strips, chips, or pieces located at desired locations of the joints. Thus, the second material 24 need only cover a portion of the first film 22A and the second surface 22B of the web of incompatible material 22 .

B. Optional intermediate steps

(1) Forming incompatible materials into granular materials

In the preferred embodiment of the method of making a tube of absorbent material shown in Figures 1-8, when the web of incompatible material 22 is positioned within a second web of material 24 prior to bonding and forming, the incompatible The web of material 22 is formed as a granular material. This is in accordance with U.S. Patent Application Serial No. 09, filed February 20, 1998, in the name of Ronald R. McFall et al., entitled "Method of Making Slotted or Particulate Hygroscopic Material," and having a common assignee with the present invention. /027379 in the method described.

In this case, it is preferred that the second web of material 24 not only has a higher bondability than the web of incompatible material 22, but also has a yield point at break of the second web of material 24 that is not comparable. The web of container material 22 has a high yield point at break. This step (granulation of the incompatible material) is an optional step which is preferably performed prior to the joining step which is much needed in the manufacture of the tube of absorbent material of the sanitary napkin shown in Figure 13 . It should also be understood that the step of forming the incompatible material into particulate material is not limited to being performed prior to the joining step. Alternatively, the step of forming the incompatible material into particulate material may be performed concurrently with, or after, the joining step, if desired. The reasons why this optional step is preferred are discussed in more detail below.

The optional process of making incompatible material 22 into granular material involves several steps. Although, there are several embodiments for this optional process (and equipment used), Figure 2 shows a preferred embodiment of the process and equipment. The process and apparatus shown in FIG. 2 is used to form an incompatible material 22 into a particulate material by mechanically deforming the incompatible material 22 .

The first step is to form a "carrier web" having a first yield point at break under tension (in the embodiment described, the second web of material 24 serves as the carrier web). The material web from which the particulate material is made (in this case, the web of incompatible foam absorbent material 22 ) and the carrier web are then formed into a composite structure, such as composite web 20 . The second yield point at break of the absorbent foam material 22 under tension is lower than the yield point at break of the nonwoven carrier web 24 . Thus, in preparation for the bonding method described herein, the first two steps of making the incompatible material 22 a granular material have already been completed.

An apparatus for mechanically deforming the composite web 20 described above is employed. The device is preferably a structure having at least one element with an embossed surface. Preferably, with this device, the embossed surface is pressed against the composite web 20 to mechanically deform the composite web 20 so that the foam absorbent material 22 is at least partially formed into a granular material, while the carrier web (material 24) second web) does not form particulate material.

The apparatus 30 for mechanically deforming the composite web 20 shown in FIG. 2 includes two pairs of cylindrical rolls, a first pair of rolls 32 and a second pair of rolls 62 . Each roll has an embossed surface. These patterns are preferably formed by a plurality of ridges and depressions on the roller, thereby forming a plurality of triangular teeth. The first pair of rollers 32 and Suitable embossing rolls for the second pair of rolls 62 (although not for turning incompatible material into granular material).

In the preferred embodiment shown, the triangular teeth on the two rollers of the first pair of rollers 32 are preferably formed by raised and lowered portions around the circumference of the rollers. The cross-section of the tooth is preferably an isosceles triangle. The tops of the teeth may be slightly rounded if desired. The top roller 34 and bottom roller 36 of the first pair of rollers 32 are aligned such that the raised portion 38 of the top roller 34 is aligned with the concave portion 40 of the bottom roller 36 . The triangular teeth forming the ridges on the top roller 34 and the depressions on the bottom roller 36 are spaced from each other so that the teeth cannot contact or fully "mesh" each other.

These teeth are of appropriate size and pitch. The term "pitch" as used herein refers to the distance between adjacent tooth apexes. In the preferred embodiment shown, the teeth preferably have a depth (or height) of about 0.1-0.17 inches (about 2.5-4.3 mm). The pitch is preferably about 1 to 5 mm, more preferably about 1.5 to 2.5 mm. The pitch of these teeth determines the width of the sheets into which the hygroscopic material is cut or split.

On the surface of the bottom roller 36 parallel to its axis X, it may also include several thin planar grooves 44 evenly spaced from each other. In this embodiment, the width of the grooves 44 evenly spaced from one another on the bottom roller 36 is preferably 2 mm. The "length" of the teeth on the bottom roller 36, measured around the circumference of the bottom roller between two spaced grooves, is 8 mm. Preferably, rollers 34 and 36 are driven to rotate in opposite directions.

The triangular teeth on the top roller 34 and the recesses 40 on the bottom roller 36 are preferably spaced apart so that they partially intermesh. The degree to which the teeth on opposing rollers engage is referred to herein as the "degree of engagement" of the teeth. Tooth engagement is defined as the position of the tooth tops on two corresponding rollers on the same plane (0% engagement) to the point where the tooth tops of one roller extend inwardly beyond said plane towards the recess of the opposite roller Planes show distances between locations. The degree of meshing of the teeth can be shown as a percentage of the pitch (distance between tooth crests on a roll), or as measured above. Since the height of the teeth can be greater than the pitch, the degree of engagement can be greater than 100% (ie: the degree of engagement is greater than the length of the pitch). Preferably, the degree of engagement is approximately 15% to 120% of the pitch length. The degree of engagement shown by the above distances measured is about 0.01 to 0.07 inches (about 0.25 mm to 1.8 mm), preferably about 0.04 to 0.06 inches (about 1 mm to 1.5 mm).

As shown in FIG. 2 , at the portion indicated by A, composite web 20 is fed into the nip between two rolls 34 and 36 in the machine direction (MD). At this stage of the process, the second web of material 24 acts as a carrier web. As a carrier web, the second web of material 24 supports and contains the web of incompatible material 22 to be slit and made into granular material. A second web of material 24 is wrapped over the web of incompatible material 22 such that the second web of material 24 faces the embossed surfaces on rolls 34 and 36 .

The embossed surfaces of rolls 34 and 36 press into composite web 20, causing composite web 20 to be mechanically deformed. The force generated by the mechanical deformation process is greater than the yield point at break of the web of incompatible foam absorbent material 22, but less than that of the carrier web (second web of higher bonding capacity material 24) made of nonwoven fabric. Break yield point; thus, the web of incompatible foam absorbent material 22 is at least partially slit without the carrier web 24 being slit.

FIG. 2 shows the state of the composite web at stage B after passing through the nip between the first pair of rollers 32 . As shown in FIG. 2, a corrugated pattern is formed on carrier web 24 corresponding to the combination of patterns on adjacent rolls 34 and 36. As shown in FIG. However, the carrier web 24 is not slit or severed. A plurality of slits 50 are formed in the middle web of foam absorbent material 22 . The slots 50 are aligned along the machine direction (MD). In the particular embodiment shown, the slits 50 are intermittent, separated by strips of material 52 in the cross-machine direction ("CD") without slits. This is due to the presence of grooves 44 on the bottom roller 36 mentioned above. Because the breaking yield point of the web of the foam absorbent material 22 is lower than the breaking yield point of the carrier web 24, the web of the foam absorbent material 22 is cut, but the carrier web 24 is not cut; Under the effect of (deformation process), the web of the foam absorbent material breaks, but the carrier web 24 does not break.

Additional steps may also be performed on the composite web 20 at this stage of the process (stage B between the first pair of rollers 32 and the second pair of rollers 62). For example, composite web 20 may be cut into individual segments between first pair of rolls 32 and second pair of rolls 62 . In other embodiments, composite web 20 may be cut into individual segments using a cutting blade placed on one of the first pair of rolls 32 . Composite web 20 is cut into lengths to accommodate the length of tube of absorbent material required for the sanitary napkin shown in FIG.

Additionally, between the first pair of rolls 32 and the second pair of rolls 62, a web (or webs) of another material, such as a continuous web of apertured film topsheet material 56, may be combined with the composite Web 20 connections. Alternatively, this additional material is cut into individual sheets and joined to composite web 20 between the first and second pair of rolls. The attachment of apertured film topsheet material 56 to composite web 20 is shown in FIG. 3 . In FIG. 2, connections are omitted for simplicity of illustration. Preferably, apertured film topsheet material 56 is attached to composite web 20 with an adhesive. The structure thus formed is referred to herein as "composite formed tube of absorbent material" (or "composite web of formed tube of absorbent material") 88 .

The second pair of rolls 62 of the apparatus 30 described above for mechanically deforming the composite web includes a top roll 64 and a bottom roll 66 . Each of these rollers has a pattern on its surface. As shown in FIG. 2, the top roller 64 has a raised portion parallel to its axis X. As shown in FIG. These raised portions form a plurality of triangular teeth 68 . Around the circumference of the top roller 64 there may be several spaced grooves 70 .

Figure 2 shows at least a portion of the foamed absorbent material 22 with a plurality of slits 80 in the cross-machine direction as the composite web 20 exits the nip between the second pair of rolls 62 . This initial slitting in the machine direction and subsequent slitting across the machine direction forms or cuts the absorbent material 22 into a plurality of particles 82 . Because there are grooves 70 on the second pair of rollers 62, some strips 84 without slits can be selectively arranged on the foam absorbent material 22; Therefore, there are also portions without slits across the machine direction.

Alternatively, the nonwoven carrier web 24 is not cut, but has another pattern formed thereon. The overall pattern formed resembles a grid with the combination of impressions created by the first and second pair of rollers 32 and 62 . The pattern formed on the apertured film topsheet 56 is similar to the pattern on the second pair of rollers 62 .

FIG. 3 shows composite web 20 after passing through the apparatus shown in FIG. 2 . As noted above, the apertured film topsheet material 56 is joined to the individual lengths of the composite web 20, preferably between the first and second pairs of rolls. Figure 3 shows that the apertured film topsheet material 56 preferably has the same width as the individual sections from which the composite web 20 is cut, and is longer than the individual sections. The apertured film material 56 extends beyond the ends of the individual segments of composite web material, so that only the ends of the material 56 need be attached to the sanitary napkin, making it easier to attach the formed tube of absorbent material to the sanitary napkin.

It should be appreciated that in FIG. 3, the pattern formed by the first and second pair of rollers pressed into the nonwoven material 24 has been omitted for simplicity. Also, for simplicity, the incompatible foam absorbent material 22 is shown as including only particles 82 (ie, the bands without slits in the incompatible material 22 are not shown). Such an embodiment can be formed by making each of the above-mentioned first pair of rollers 32 and the second pair of rollers 62 have continuous teeth, and omitting the recessed portion 40 and the groove 70 between the teeth.

(2) Optional step of folded composite web of hygroscopic material tube

The next step in making the tube of absorbent material for the sanitary napkin shown in Figure 13 is folding the composite web 20, the composite web 88 of the apertured film topsheet material sheet 56 and the formed tube of absorbent material. These are optional. However, the preferred folding procedure is shown in the following figures.

Figure 3 shows the longitudinal fold line F about which the longitudinal side margins of the composite web 88 of the formed tube of absorbent material described above begin to fold. FIG. 4 shows the "C" folded structure of the formed composite web 88 of the tube of absorbent material after folding the above-mentioned side margins 90 along the fold line F in the first folding step.

Figure 5 shows the composite web 88 of the formed tube of absorbent material after folding during the second folding step. As shown in Figure 5, the formed composite web 88 of the tube of absorbent material is folded along its longitudinal centerline L. As a result, the previously folded longitudinal side margins 90 approach each other and the longitudinal side margins 90 of the composite web 88 of the formed tube of absorbent material are crimped inwardly of the composite web 88 . As shown in Figure 5, the folded longitudinal side margins 90 are adjacent the longitudinal centerline L of the composite web 88 of the formed tube of absorbent material. The composite web 88 of the folded formed tube of absorbent material shown in Figure 5 is now readily joined using the method of the present invention. (The steps shown in Figures 2 to 5 are all optional, but ideal steps for making the tube of absorbent material of the sanitary napkin shown in Figure 13).

C. Joining (and forming) of incompatible materials

(1) Preamble

To bond (and shape) the incompatible absorbent foam material 22, typically, a web of material 24 (nonwoven fabric) having a higher bonding capacity is placed over the incompatible material 22 (hygroscopic foam material) outside. The cross-section of the actual structure to be joined (shown in Figure 7) is more complex, but for illustration it is best to show the general relationship above (the web with the higher second joining capacity material placed on the outside of the web of incompatible material).

The incompatible absorbent foam material 22 is joined to the outer web of nonwoven material 24 having a second higher joining capacity, preferably with a plurality of self-generating joins 94 . As used herein, the term "self-generating" refers to joining that occurs without the use of adhesives or other additional materials (ie, materials that are additionally added to the elements to be joined), such as sewing thread. However, the methods described here are not limited to such autogenous bonds without adhesive reinforcement, or adhesive bonds themselves.

Preferably, said junction 94 penetrates the non-compatible absorbent foam material 22 . Preferably, the junction 94 joins one portion of the web of nonwoven fabric 24 to another portion of the web of nonwoven fabric 24 on the opposite side of the incompatible foam material 22 . In the illustrated embodiment, bonding, as a step of the method of the present invention for bonding incompatible materials, can also be used to form tubes of absorbent material having unique three-dimensional shapes.

Any suitable number of junctions 94 may be used when using the method of the present invention. The junction 94 may be located at any suitable location. To make the tube of absorbent material of the sanitary napkin shown in Figure 13, preferably 2-5 joints 94 are used. In the illustrated embodiment, three joints 94 are used. The joins 94 are preferably spaced about 1.75 inches (about 4.4 cm) apart from each other and about 17 mm from the fold line formed along the longitudinal centerline L of the composite web 88 of the formed tube of absorbent material described above.

The autogenous bonding process described above can be performed using heat and/or pressure, or ultrasound. Suitable methods of thermal and/or pressure bonding, especially dynamic bonding, are described in more detail below. Corresponding ultrasonic bonding methods are described in U.S. Patent No. 4,430,148, issued to Schaefer on February 7, 1984, entitled "Ultrasonic Bonding Method", Procter & Gamble Company; and Willhite Jr. et al., issued April 25, 1989, entitled "Jointing of Continuously Moving Webs Without Adhesives to Form Laminated Webs and Products Cut from the Webs" is described in US Patent No. 4,823,783. Suitable ultrasonic bonding equipment is commercially available from Branson Ultrasonics of Danbury, CT. The ultrasonic bonding device is preferably equipped with a flat plate having the same pattern elements as those of the dynamic bonding method described below. It should be appreciated, however, that ultrasonic bonding may not be the most preferred (compared to dynamic bonding methods) when used to bond certain thicker structures as described herein.

The dynamic bonding method has several advantages over the ultrasonic bonding method. First, the dynamic bonding method is a continuous method that can be performed at high speed. In contrast, typical ultrasonic bonding requires the use of devices having at least one stationary head, requiring a fixed dwell time in order to form the bond. Therefore, when using ultrasonic bonding methods, the webs to be bonded must be stopped for a period of time to complete the bonding. Second, ultrasonic bonding methods are not suitable for bonding materials whose thickness exceeds a certain amount (eg, up to, or greater than, or equal to about 4 mm). On the other hand, the dynamic bonding method described herein can easily bond materials having such thicknesses.

During the joining process, it is advantageous to cut or granulate the hygroscopic material 22 in a previous step. This is because the method used to form the slit or granular material creates a continuous, clear path for the joint contact hygroscopic material. This is even more achievable if the joints are aligned with the slits or spaces between the particles. This is most likely to occur when slits or granular material are bonded to the carrier web as described above. The existing method of cutting the hygroscopic material only cuts the hygroscopic material and blows the hygroscopic material into a closed tube with compressed air, so that the cut particles are randomly distributed. This method cannot form the clear bonding path described above.

The dynamic joining method described above involves joining together the portions of the second web of material 24 (nonwoven cover) on either side of the absorbent foam material 22 . The apertured film topsheet material 56 may also have sections that are dynamically bonded together. Additionally, or alternatively, an apertured film topsheet material 56 is bonded to the joining portion of the nonwoven web 24 . When dynamic bonding is used, preferably at least one of the materials to be bonded (nonwoven cover 24 or apertured film topsheet material 56) is thermoplastic. (It should be understood that, for simplicity, the joining is shown below as joining portions of the nonwoven web 24 joined together; of course, an apertured film topsheet material could equally be joined in this way, but is not shown).

Figure 8 illustrates the process by which the first portion 24A of the cover material 24 is joined to the second portion 24B of the cover material, preferably by the composite web 88 of the formed tube of absorbent material described above. The means for joining the composite web 88 of the formed tube of absorbent material preferably includes a pair of cylindrical rolls 110 and 112 . Preferably, at least one roll, such as embossing roll 110, has an embossed pattern on its surface. The embossing roll 110 is shown briefly in Figure 8 and in more detail in Figure 12 (although Figure 12 shows a roll with a relief pattern which is slightly different from the pattern shown in Figure 8).

As shown in Figure 12, the embossing roll 110 has a cylindrical surface 115, and a plurality of protrusions or pattern elements (or "pattern blocks", "bumps" or "nubs" extending outwardly from the surface 115) )116. The relief pattern formed by pattern elements 116 may be of any shape. The relief pattern may be straight, curved, or may consist of straight and curved portions. The relief pattern can be continuous or intermittent. Embossing patterns can be formed into an infinite number of patterns and other styles. For example, embossed patterns can form some geometric shapes, arrows, words, etc. The contact surface 118 on the tread element can also be formed in various shapes. Suitable shapes for the contact surface 118 include, but are not limited to, oval and circular.

In the embodiment of the device shown, the relief pattern comprises a plurality of spaced apart pattern elements 116 having a circular contact surface 118. In the embodiment of the method shown in FIG. 8, the pattern elements 116 are arranged in intermittent lines .

Although the present invention is applicable to joints of any shape and size, it is preferred that the joint be circular in plan view with a diameter of about 0.25 to 5 mm or more. In a preferred embodiment, the diameter of the joint circle is about 3 mm and the area of the circle is about 8 mm ² .

The pattern elements 116 have sidewalls 119 that are preferably non-perpendicular to the cylindrical roller surface. Typically, the angle between the sidewall 119 of the pattern element 116 and the surface 115 of the cylindrical roller is greater than 45° and less than 90°; preferably about 70° to 90°. Due to the thickness of the materials to be joined, and the desire to avoid tearing the nonwoven cover material 24 described above, it is desirable to vary the orientation of the sidewalls 119 of the tread elements 116.

The other roller 112 acts as an anvil member and may therefore be referred to as an anvil roller 112 . Between the embossing roll 110 and the anvil roll 112, a gap 114 deflected by pressure is formed. Preferably, the surface of anvil roller 112 is smooth. However, in other embodiments, both rollers 110 and 112 may have relief patterns and/or pattern elements. Preferably, the embossing roll 110 and the anvil roll 112 are offset toward each other by a predetermined pattern element load of about 20,000 psi (about 140 MPa) to about 200,000 psi (about 1400 MPa) . In the embodiment shown in FIG. 8, the two rollers 110 and 112 are offset toward each other to maintain a pressure in gap 114 of approximately 93,700 psi (approximately 656 MPa). In this embodiment, the materials to be joined pass through gap 114 at a relatively high velocity. The linear velocity of the material through the gap is preferably about 383 ft/min (about 117 m/min).

The embossing roll 110 and anvil roll 112 are preferably driven in the same direction at different speeds; thus, there is a surface speed difference between them. The surface speed difference is preferably about 2%-40% of the speed of the lower surface speed roll, more desirably about 2%-20%. The surface speed of anvil roll 112 is preferably greater than the surface speed of embossing roll 110 . However, when the line speed is high, it is also possible to carry out splicing with zero speed difference (ie: the surface speeds of the rollers forming the aforementioned gap are equal).

Multiple sheets of composite web 88 comprising the formed tube of absorbent material described above may be joined by passing through nip 114 between rolls 110 and 112 . The illustrated preferred joining process may pass through the formed composite web 88 of the tube of absorbent material and self-join the first portion 24A of the nonwoven cover material 24 with the second portion 24B of the cover material 24 . A joint 94 is formed between two opposing portions of the web of nonwoven material 24 having a second higher joining capacity that are outside of the foam material 22 .

Without being bound by any particular theory, it is believed that the mechanism by which incompatible materials join is as follows. The patterned elements 116 on the rollers of the engaging means compress the incompatible absorbent foam material 22 . This localized compression causes the incompatible absorbent foam material 22 to rupture and separate from the area of the tread element 116 (away from the point of application of the pressure). The bonding means cuts apart the incompatible material 22, or dislodges particles of the incompatible material 22, thereby forming a clear path for bonding the materials to be bonded together. Preferably, very little, if any, foam material 22 is left at the joint.

In addition to the ability of bonding to penetrate into incompatible materials, the method described has several other important features. These features allow the joining of large thicknesses of material and the formation of a virtually infinite number of joining patterns on the materials to be joined. The embossing roll 110 preferably has a compliant (or compressible) material 120 on the surface 115 thereof. The embossing roll 110 also preferably has two composite supports 122 on the surface 115 thereof. The function of these parts will be explained below.

The function of the compliant material 120 is to compress the materials to be joined so that the tread elements 116 do not puncture the cover material 24 . If the cover material 24 is punctured, the bond cannot be formed, or the bond formed is weak because the covering nonwoven material will not melt to form the bond. The step of compressing can be performed prior to bonding, or simultaneously with bonding. The use of a compliant material on the patterned roller 110 is particularly suitable when the materials to be joined are thick. Compliant material can be omitted when the materials to be joined are thin. FIG. 12 shows that the compliant material 120 surrounds the pattern elements 116 described above.

The effect of the compliant material 120 can be seen by comparing Figures 9 and 10. FIG. 9 shows the passage of thicker material through the gap 114 between the embossing roll 110 and the anvil roll 112 , where no compliant material surrounds the pattern elements 116 . As shown in FIG. 9 , the pattern elements 116 puncture the materials to be joined due to the high localized stress on the materials to be joined, particularly the covering material 24 .

FIG. 10 shows the same thicker material passing through the gap 114 between the embossing roll 110 and the anvil roll 112 of the pattern element 116 surrounded by compliant material 120 . As shown in FIG. 10 , compliant material 120 occupies the space between embossing roll 110 and anvil roll 112 . The compliant material 120 progressively compresses the material to be joined over the tread element 116 area. This brings the two layers of covering material 24 closer together during bonding without causing additional deformation of covering material 24 . This makes it possible to form the joint 94 without tearing the cover material 24 or poking a hole in the foam material 22 between two layers of the cover material 24 .

The working of this method can be seen by imagining the following simulation situation. The principle of this method is similar to that used to fasten 6-inch (15 cm) thick fiberglass insulation to another material with a nail gun. If the fiberglass is not compressed, the nail will pierce the insulation and go all the way through the insulation when the nail is fired. However, if you compress the fiberglass insulation before fixing it with a nail gun, this will not happen and the nails will hold the insulation in place.

The compliant material 120 preferably has certain properties. The compliant material 120 is less compressible than the material to be joined, but more compressible than the surface 115 of the embossing roll 110 . Therefore, the hardness of the compliant material 120 should be less than the hardness of the surface 115 of the embossing roll 110 . Generally, the hardness of the compliant material (measured with a durometer) is between about 50 on the Shore A scale and about 62 on the Rockwell C scale; preferably about 50 to 100 on the Shore A scale; most ideally about 50 on the Shore C scale Hardness A scale 90. (Rockwell C scale 62 is the hardness of the D ₂ steel making up the surface 115 of the embossing roll 110). (Although the hardness of the surface of the anvil roll may be any suitable value, it is preferably equal to or greater than the hardness of the surface 115 of the embossing roll 110).

The compliant material 120 can be any form of material. Suitable materials include brass, rubber, and polymeric materials such as polyurethane. In a preferred embodiment, the compliant material 120 is polyurethane.

The width of the compliant material 120 should be wider than the width of the material to be joined. This allows the pressure to be equalized across the materials to be joined. The thickness of the compliant material 120 can be any suitable size. Preferably, the thickness of the compliant material 120 is large enough to contribute to avoiding the problems of perforation in the cover material 24 as described above. The thickness of the compliant material 120 is preferably no greater than the height of the tread elements 116 described above. For example, the height of the tread elements is approximately 2mm. In one non-limiting example, a polyurethane compliant material having a hardness of about 90 on the Shore A scale was found to be suitable having a thickness of about 1.5 mm.

The compliant material 120 is preferably bonded to the surface 115 of the embossing roll 110 . The compliant material may be attached to embossing roll 110 by any suitable method, such as welding or adhesives.

The load support 122 described above functions to balance the embossing roll 110 (ie, to even out the force on the embossing roll 110 as the material to be joined passes between the embossing roll 100 and the anvil roll 112). The use of a load support 122 is particularly advantageous when the pattern on the embossing roll 110 is "uneven" or "erratic". By "uneven" or "unstable" it is meant that the above-mentioned pattern elements 116 on the embossing roll 110 are distributed such that the pressure in the gap 114 between the embossing roll 110 and the anvil roll 112 surrounds the embossing roll 110 The circumferential variation of , which is due to the surface area of the contact surface 118 of the pattern element 116 is different, and/or the distribution of the pattern element 116 is caused.

When the engaging pattern is balanced, the load bearing 122 may be omitted. However, as will be explained in more detail below, even when the engaging pattern is a balanced pattern, it is still desirable to use load bearing members 122 for greater flexibility in using taller pattern elements 116 .

The shape of the load support 122 may be any suitable shape. The load support 122 may be in the form of a continuous ring surrounding the embossing roll 110 . The load support 122 may also be in the form of an intermittent part. If the load support members 122 are in the form of intermittent pieces, they are preferably staggered around the circumference of the embossing roll 110 so as to effectively form a continuous ring around the circumference of the embossing roll 110. As shown in FIG. 12, the load support member 122 is preferably in the shape of a continuous ring surrounding the embossing roll 110. As shown in FIG.

In the illustrated embodiment, two load supports 122 are preferably located near each side edge of the embossing roll 110 . The two load supports 122 are preferably located laterally outward of the surface 115 of the embossing roll 110 that is in contact with the material to be joined (i.e., the load supports are preferably located at the central portion of the embossing roll 110 and at the side edges of the embossing roll 110 between). This ensures that the anvil roller 112 is in direct contact with the load support 122 . When the material to be joined is fed into the gap 114 between the two aforementioned rollers 110 and 112, the anvil roller comes into contact with the load support. This contact occurs due to the compression of the materials to be joined in the aforementioned gap 114, and due to the deformation of the two rollers under the action of a relatively high force which biases the two rollers towards each other.

Comparing Figures 11 and 12, the function of the load support 122 can be seen more closely. FIG. 11 shows an example of an embossing roll 1110 without the load support described. The distribution of pattern elements 1116 on embossing roll 1110 is "telescopic" and balanced. As used herein, the term "nested" means that when the pattern is viewed around the circumference of the embossing roll 1110, the distribution of pattern elements 1116 overlaps to some degree. This ensures that, in the region of the gap 1114 , the anvil roll 1112 is continuously positioned on top of the embossing elements 1116 without falling or sinking between the pattern elements 1116 . If the above-mentioned pattern elements 1116 were not nested, the anvil rollers 1112 would indeed sink between the pattern elements 1116, and the two rollers brought close together under great pressure and turning at high speed would be like a flat tire on a car , it works very unstable.

In the roller 1110 shown in Figure 11, there are sets of pattern elements that are identical to the sets of pattern elements on the rest of the roller. Additionally, there are supports or a band of supports 1124 between sets of pattern elements. Since only a portion of the roller surface is shown in FIG. 11 , several sets of identical pattern elements on other portions cannot be seen in FIG. 11 . However, the illustrated set of pattern elements and support 1124 is sufficient to illustrate the concept of the problem. As shown in FIG. 11 , when the pattern is a balanced pattern, only discontinuous (or intermittent) supports or support strips 1124 need be provided around the circumference of the embossing roll 1110 . The support body 1124 should be arranged at a position where no tread elements 116 are present. This is because, as the embossing roll 1110 rotates, the overall force generated by the loading mechanism is transferred from the pattern elements to the support 1124 . The need for a balanced pattern means that at any point around the rollers, the engagement area in the gap (ie, the surface area of the portion of the two rollers in contact within the gap) must remain constant. If the joint area changes, the joint pressure will also change, making each joint inconsistent.

Figure 12 shows an example of an embossing roll 110 with pattern elements 116 having a non-nesting and unstable pattern that may be used in embodiments of the method. Although only a portion of a roller 110 with a set of pattern elements 116 is shown in FIG. (By "point" is meant that the pattern elements have circular contact areas). Each set of points is distributed in the desired manner to form a joint on the product. For example, to join a composite web of formed tubes of absorbent material as shown in Figure 8, each set of points may consist of three points aligned. To engage the interlabial absorbent article 1020 shown in Figure 15, each set of points may consist of 4 or 5 points arranged in a semicircle, as in the case of the set of pattern elements shown in Figure 16.

For purposes of discussion, assume that there are six sets of points around the circumference of the roller 110 . All tread elements 116 in this example are the same height. In three of the dot patterns the pattern elements 116 have a contact surface with a circular engagement surface having a diameter of 2 mm. In the other three dot patterns the tread elements 116 have a contact surface with a circular engagement surface having a diameter of 3 mm. Pattern elements 116 with a contact surface of 3 mm diameter and pattern elements 116 with a contact surface of 2 mm diameter are alternately arranged around the circumference of the embossing roll 110 .

Prior to the invention of the load bearing member 122 described herein, the inventors were not aware of a convenient way to form the joint using tread elements with a 2 mm diameter contact surface and tread elements with a 3 mm diameter contact surface. For example, with conventional roller constructions, joints can only be formed with tread elements with a 2mm diameter contact surface, but not with tread elements with a 3mm diameter contact surface. If an appropriate pressure is chosen to form a joint with a patterned roller with a 2 mm diameter contact surface, there will be insufficient pressure to form a joint with a patterned roller with a 3 mm diameter contact surface. The reverse is also true (ie, a joint can be formed with a tread element with a 3 mm diameter contact surface, but not with a tread element with a 2 mm diameter contact surface). If an appropriate pressure is selected to form a joint with a tread element with a 3 mm diameter contact surface, the pressure will be too high when a joint is formed with a tread element with a 2 mm diameter contact surface, and will puncture the material to be joined. Make some through holes.

Accordingly, the load bearing 122 described herein was developed. Preferably, these load bearing members 122 are in the form of a continuous ring around the circumference of the embossing roll 110, as described above. To ensure dynamic balance of the embossing roll 110, material equal to the surface area of the pattern elements is removed from the load support. As shown in FIG. 12, there are small cut-out areas 126 on each side of the load support member 122. As shown in FIG. The locations of these cut-out areas 126 are preferably located along the same longitudinal axis on the roll surface on which the pattern elements 116 are located. For each pattern element 116 there are two cut-out areas 126 . Each cut-out area 126 shown in FIG. 12 has a semicircular shape. The size of each cut-out area is preferably half the size of the surface of the tread elements 116 lying on a common longitudinal axis.

The hardness of the load bearing 122 is greater than or equal to the hardness of the surface of the embossing roll 110 and the pattern elements 116 . Load support 122 may be made of any suitable material. As with the surface of embossing roll 110 and pattern elements 116, load support 122 is preferably made of _D2 steel.

The thickness of the load bearing 122 may be less than, greater than, or equal to the height of the tread elements 116 . To simplify the joining process, the thickness of the load bearing member 122 is preferably the same as the height of the tread elements 116 . For example, the height of the tread elements 116 is approximately 2 mm. In one non-limiting example, a load support 122 approximately 2 mm thick is also suitable. The width of load support 122 may be any suitable value. Preferably, the width of the load bearing member 122 is such that the surface area of each portion along the longitudinal region (i.e., the direction parallel to the roller axis) of the surface of the embossing roller 110 is equal to or greater than the contact surface 118 of the pattern element 116 located in the same region of the total surface area. In the embodiment shown in FIG. 12, the width of the load support member 122 is approximately 6 mm (measured through the portion of the load support member 122 excluding the cut-out region 126).

The load bearing member 122 can be integral with the embossing roll 110; Preferably, the load support member 122 is integral with the surface 115 of the embossing roll 110 . If the load support 122 is bonded to the embossing roll 110, the bonding may be done by any suitable method, such as welding.

Without needing to be bound by any particular theory, it is known that the load bearing member 122 can be used to engage with uneven treads because the pressure in the joint area does not vary only with the surface area allowed by the tread or with or without tread elements. . When load support 122 is employed, the pressure in the joining zone is controlled by: the material properties of the rolls, particularly of embossing roll 110; the properties of the material to be joined; and the geometry of pattern elements 116 and load support 122 Shape (ie, height and surface area). Due to the high pressure at which the engagement takes place, the rollers, especially the pattern elements 116, are deformed. The pressure in the land can cause the tread elements 116 to be compressed to deflect. The pressure of the land may also deflect the surface of the embossing roll 110 around the root of the pattern elements to some degree. At the point of contact with the pattern element 116, the anvil roller 112 may also be deformed locally.

The amount of deformation of the pattern element 116 and its surrounding area corresponds to the thickness of the joint formed in this way. In the preferred embodiment described herein, the joint has a thickness in the range of approximately 0.0015 to 0.002 inches (approximately 0.038 to 0.05 mm). This deformation keeps the anvil roll 112 in contact with the load bearing 122 even when the area with the pattern element 116 and the material to be joined is fed into the gap 114 between the embossing roll 110 and the anvil roll 112. constant contact. For this reason, the loading force must be large enough to ensure constant contact of the load bearing member 122 with the anvil rollers. In this manner, the load bearing 122 acts as a "stop" for the anvil roller 122 to prevent further compressive deflection of the pattern elements 116 .

The strength of the load bearing member 122 should be designed to be large enough so that once the anvil roller 112 is in contact with the load bearing member 122, the engagement pressure on the pattern elements 116 will not increase further. If the load bearing 122 is very stiff, only the load on the load bearing 122 increases when the loading force increases.

The balance of the embossing roll 110 is of particular importance. This aspect of the joining method can be exploited to form the joining pattern by means of pattern elements having differently sized contact surfaces around the circumference of the embossing roll. This aspect of the joining method is also characterized by the previous mechanical limitations. The joining pattern does not have to be telescoping, nor does it have to be a balanced pattern. For example, using previous joining methods, producing a nested and balanced complex pattern such as the pattern shown in Figure 17 requires a very complex design process. The balancing of the embossing rolls eliminates the need for complex design work to ensure nesting and balancing of the joining pattern.

In addition, it is possible to produce some joint patterns suitable for some special joint needs or user preferences, rather than limited by the method. Additionally, the methods described herein may be used to create an unlimited number of joining patterns as desired for aesthetic or other purposes. For example, using the methods described herein, handwriting or a picture can be stamped on the materials to be joined.

Additionally, the use of load bearings 122 in the present method allows the use of much taller tread elements 116 . Typically, existing tread elements have a height of about 0.015 inches (about 0.38 mm). As described herein, the height of the tread elements 116 can be up to 2 mm or greater. In this way, thicker materials can be joined. However, embossing rolls with taller pattern elements are not limited to joining thicker materials. It can also be used to join thinner materials because the load bearing 122 keeps the pattern elements 116 from piercing the material to be joined.

This aspect of the method also results in increased embossing roll 116 life. Typically, patterned roll wear is due to stress on the pattern elements. The use of load bearings can take some of this stress and relieve the stress on the tread elements, thereby reducing stress. As also mentioned above, the load bearing member may also act as a "stop" to prevent further compression deflection of the tread elements. Since the load bearing member acts as a "stop" against further compressive deflection of the tread element, the tread element will not deform beyond its plastic deformation point.

(2) Non-limiting variations of joining methods

There are many variations on the bonding method. Some such non-limiting variations are described below.

For example, the methods described herein are not limited to materials used to join absorbent articles. For example, the methods described herein may be used to join materials used in the manufacture of packaging articles, or any other form of article, particularly those using incompatible materials, polymeric materials, and the like. Additionally, the central sheet of materials to be joined need not include incompatible materials. It may contain any form of suitable material including, but not limited to, thermoplastics.

In addition, the roller structure of the bonding method described here is not limited to the structure shown in figure. For example, in other embodiments, both rollers may have patterned elements. In embodiments where both rollers are provided with patterned elements, the patterned elements may contact each other. Alternatively, the pattern elements on one roller may be in contact with the surface of the opposing roller at positions between the pattern elements on the surface of the other roller. In addition, the load support members are not limited to be provided only on the embossing rolls. The load support can be provided on an anvil roll, or on both an embossing roll and an anvil roll.

The load support shown in Figure 12 can also be varied in many ways. For example, the load support may have at least some discontinuities while the embossing roll 110 still has some or all of the advantages described. Additionally, the shape of the cut-out area on the load bearing need not be half the shape of the tread element.

A preferred method of dynamically joining these materials may also include the step of heating one or both of the rollers 110 and 112 . If the roller is heated, it is preferable to heat the roller to the extent that its surface temperature is lower than the melting temperature of the thermoplastic material in the above-mentioned covering material 24 by a predetermined value.

In other embodiments, the materials to be joined may be compressed (or "pre-compressed") prior to being fed into the aforementioned gap 114 for joining. For example, the materials to be joined may be pre-compressed by passing them through a pressurized gap between another pair of rollers located ahead of rollers 110 and 112 . Precompressing may include compressing the entirety of the material to be joined, or locally compressing the regions of the composite web 88 of the formed tube of absorbent material described above where the join 94 will be formed.

In other joining methods, a pre-compression step can also be performed together with the joining. For example, if ultrasonic waves are used, the ultrasonic welder or "stake" will typically compress the materials to be joined to some degree during the dwell time required to form the ultrasonic bond. Thus, in the case of conventional ultrasonic welding, a pre-compression step separate from the generally used joining process may not be required.

In addition, for simplicity and clarity of description, the device used in the bonding method of the present invention is described as including two cylindrical rollers 110 and 112, however, the cylinder is only an exemplary gap-forming part. Thus, the invention is not limited per se to devices comprising cylindrical rollers. Likewise, use of the term "tread element" is not intended to limit the method described to joining patterns consisting only of individual, spaced-apart pattern elements, nor to exclude other patterns, such as reticulated patterns or patterns comprising continuous, Or a pattern of thin and long seams.

The methods described herein may also include any of the method limitations or steps described in US Patent No. 4,854,984, issued August 8, 1989 to Ball et al.

Another factor that should be considered when engaging using dynamic engaging methods is the even distribution of load on the tread elements. This is important when using one joining roller or surface to join materials having sections of different thicknesses. Different thicknesses may appear on the material in several different cases. For example, the materials to be joined can be profiled or calendered so that some areas have different thicknesses. Alternatively, the materials to be joined may be a laminate in which all the layers differ in length and/or width. In this case, some joints pass through more layers than others when joined.

In this case, one way to distribute the load evenly across the pattern elements is to vary the angle of the side walls 119 of the pattern elements 116 . The angle of the sidewall 119 of the tread element 116 penetrating through the thicker portion of material to be joined should be greater than the angle of the sidewall 119 of the tread element 116 penetrating through the thinner portion of material to be joined. For example, the angle of the sidewall 119 of the tread element 116 that penetrates the thinner portion of the material to be joined is approximately 50°; and the angle of the sidewall 119 of the tread element 116 that penetrates the thicker portion of the material to be joined is approximately 70°. The height of the tread elements 116 penetrating the thicker portions of the material to be joined may also be greater (or the additional tread elements made shorter) if desired.

As noted above, the methods of the present invention may be accomplished using adhesives, co-adhesives, hydrogen bonding (eg, if one of the materials to be bonded includes cellulose), heat and/or pressure, or ultrasonic means. However, it is best to use dynamic bonding methods or ultrasound. This approach is particularly advantageous if the materials to be joined (eg, the second web of material 24) are treated with chemical agents or compositions that conflict with conventional joining methods, particularly adhesives. This method of attachment is advantageous if the second material is treated with a skin care composition or a material that alters the hydrophilicity of the second material.

An example of the latter form of surface treatment is given to Yan-Per Lee et al. on December 2, 1997, to P&G Corporation entitled "Absorbent Articles with Improved Hydrophilic Topsheets Treated with Surfactants". It is described in US Patent No. 5,693,037. The described dynamic bonding methods and ultrasonic bonding methods can bond such treated materials, or transfer sufficient heat through such coatings or treated surfaces to form bonds with underlying materials. Alternatively, if the surface treatment is to be continued only, the joining means can be patterned so that the joint penetrates the untreated portion of the material.

FIG. 7 shows that the join can compress or more preferably displace the compressible foam absorbent material 22 over the localized area forming the join 94 . In this way, the three-dimensionally formed portion 100 of the composite web 88 of the formed tube of absorbent material can be isolated from the rest of the composite web 88 of the formed tube of absorbent material, and the isolated portion 100 (and the entire formed tube of absorbent material) The composite web 88) is made into different shapes. The composite web 88 of the formed tube of absorbent material is formed, preferably symmetrically, on both sides. This bi-lateral symmetry of the web 88 is achieved because splicing applies pressure only to the portion of the formed composite web 88 of the tube of absorbent material which is pressed by the pattern elements 116 against the curved surfaces of the anvil rolls. Thus, this embodiment of the method of the invention differs from embossing methods which can form structures with one embossed side and one flat side.

D. Fixing the tube of absorbent material on a base pad to form a composite sanitary napkin

Following the joining process, the joined formed composite web 88 of absorbent material tubes is preferably cut into a plurality of individual absorbent material tubes, each of which is placed on a base pad to form a composite sanitary napkin.

As shown in FIG. 8, the means for severing the composite web 88 of joined formed tubes of absorbent material includes a pair of rolls 130 and 132. As shown in FIG. One of the rollers-roller 130 has at least one, and preferably a plurality of, scraper elements 134 on its surface. Preferably, the blade member 134 is shaped to form continuous, generally transverse cuts in the composite web 88 of the continuously joined formed tube of absorbent material. Another roller 132 acts as an anvil member and may therefore be referred to as anvil roller 132 . A gap 136 is also formed between the doctor roll 130 and the anvil roll 132 . After the cutting step, the individual tubes of absorbent material 88 are conveyed onto a conveyor belt 140 for attachment to the base pad as described above to form compound sanitary napkins.

In the case of a single tube of absorbent material shown in FIG. 7, the remaining portion 102 of the composite web 88 of the formed tube of absorbent material that is secured together without jointing is unrolled, and the composite web of the tube of absorbent material to be formed 88 to spread it out before attaching to the base pad. Joining and unrolling of the remaining portion 102 of the formed tube of absorbent material composite web 88 makes the formed composite tube of absorbent material web 88 into a contoured shape wherein the composite web 88 constituting the top of the tube of absorbent material on the finished product Some widths are narrow. As best shown in Figure 13, the portion of the composite web 88 that forms the top of the tube of absorbent material on the finished product forms raised portions 106 that project vertically from the top of the remaining portion 102 of the composite web (and the remainder of the sanitary napkin). As also shown in Figure 13, splicing also allows the composite web 88 of the formed tube of absorbent material to have a honing pattern where the composite web 88 of the tube of absorbent material formed is wrinkled around the joint 94. rise.

Figure 13 shows a compound sanitary napkin having a tube 88 of absorbent material joined by the method of the present invention on the body-facing side.

To form the composite sanitary napkin 800, a sanitary napkin can be utilized as the panty protector (or "base pad") 820, and a tube of absorbent material 88, the "primary menstrual pad," is placed on top of the base pad 820, allowing at least The two ends of the tube of hygroscopic material are connected with the foundation pad. Sanitary napkins suitable for use as base pad 820 include ALWAYS ULTRA sanitary napkins sold by The Procter & Gamble Company of Cincinnati, Ohil.

In a particularly preferred embodiment, the base pad 820 comprises a variation such as the ALWAYS ULTRA sanitary napkin having an absorbent core, a tissue overlying the absorbent core, and a DRI-WEAVE apertured film comprising an ultra- Tissue laminated sheets of hygroscopic hydrogel-forming material particles. Suitable tissues are those manufactured by Merfin Ftygienic Products. The tissue covering the absorbent core is preferably attached to the absorbent core by a spiral of adhesive.

Tubes of absorbent material 88 may be attached to base pad 820 by any suitable means. The tube 88 of absorbent material is attached to the compound sanitary napkin 820 by fusion bonding the extension 58 of the topsheet material 56 to the base pad 820 at both ends of the tube of absorbent material. In certain preferred embodiments of the compound sanitary napkin, a tube of absorbent material may also be attached to the base pad between the tube 88 of absorbent material and the end of the base pad 820. The tube of absorbent material of the composite sanitary napkin is joined between its ends to the base pad by any suitable joining method, such as adhesives.

The sanitary napkin 800 has a first end (or front) region 828, a second end (or rear) region 830 and a central region 832 between the first and second end regions. As shown in Figure 13, as a result of the bonding, the tube 88 of absorbent material is contoured from the front end region 828 of the sanitary napkin 800 to the rear end region 830 thereof. More specifically, the tube 88 of absorbent material is thickest along the transverse centerline T at the center of the compound sanitary napkin; and gradually decreases in thickness toward the ends of the compound sanitary napkin.

The joining pattern can be varied such that the thickness of the tube of absorbent material increases along the entire length or part of the length of the compound sanitary napkin 800 . For example, it may be joined such that the increased thickness of the compound sanitary napkin 800 is limited to the central region 832. Alternatively, the sanitary napkin may be provided with increased thickness in the end regions, or with a portion of the central region and a portion of the end regions, by use of the joining pattern.

2. Alternative Embodiments of the Method of the Invention

The present invention has many alternative embodiments. For example, in an alternative embodiment, the absorbent material in the tube of absorbent material need not be granulated prior to joining, ie, a monolithic piece of absorbent material can be used. However, joining through an entire piece of absorbent material (such as foam absorbent material) is difficult, especially if the thickness of the material exceeds about 4mm.

Additionally, other forms of materials, such as low density hygroscopic materials, may also be joined using the method of the present invention. For example, non-calendered airfelt can be joined using the method of the invention. If desired, the air felt can be calendered, but only after the air felt has been encapsulated with the material to be joined and joined according to the method of the invention.

However, the method of the present invention has several advantages over methods of simply embossing absorbent articles such as absorbent articles comprising embossed airfelt absorbent cores. In such absorbent articles, the topsheet may be bonded to the absorbent core of the airfelt. The backsheet can also be bonded with air felt. Cellulose fibers in air felt are held together by hydrogen bonds. The disadvantage of these hydrogen bonds is that they can be loosened by liquids. Adhesives also have the disadvantage of being loosened by liquids, and certain surface treatments of absorbent article components such as topsheets can also loosen adhesives.

Figure 14 shows another application of the method of the invention. In the previous embodiment, the method of the present invention included placing the joinable material on the outer surface of the incompatible materials and then joining the materials together by penetrating the incompatible materials. In FIG. 14, the method of the present invention is used to join two pieces of incompatible materials with a joinable material placed inside the incompatible materials.

FIG. 14 shows two webs of incompatible material 22 . The web of incompatible material 22 can be any of the incompatible materials described herein. Preferably, the web of incompatible material comprises an absorbent foam material. Although it is difficult to fix this absorbent foam material to other materials using adhesives, in this embodiment, a layer of adhesive 98 is used to bond each web of absorbent foam material 22 to the material 24 with higher bonding ability. web splicing. However, such bonding runs the risk of detaching the absorbent foam at the bond because of the poor structural integrity of the absorbent foam. The web of higher bondability material 24 can be any of the second materials described herein. Preferably, the web of higher bondability material 24 comprises a web of nonwoven material.

As shown in Figure 14, the web of absorbent foam material 22 bonded to the nonwoven web 24 is placed adjacent to each other face-to-face. The overall composite structure thus formed is then joined together using the methods described herein. The composite structure may be joined by passing through a gap between a pair of rollers in an apparatus such as that shown in FIG. 8 . This allows a joint 94 to be formed between two webs 24 of nonwoven material.

The seam 94 in this embodiment may be a "hidden" seam that is not visible from the outside of the absorbent foam material 22. The joint 94 may be hidden because the patterned elements forming the joint generally displace only a small amount of foam material. In addition, after joining, the foam 22 can be re-rolled over the joint area so that the displacement of the removed foam is less visible.

Additionally, the methods described herein can be used for other purposes and to make other forms of absorbent articles. For example, Figure 15 shows an interlabial absorbent device 1020 joined and formed using the method of the present invention. The interlabial absorbent device 1020 can be made of suitable absorbent materials including any of the incompatible materials described herein. In the embodiment shown in Figure 15, the interlabial absorbent device 1020 is constructed of a rayon core 1044 surrounded by a layer of nonwoven web cover material 1046 . Rayon is generally an incompatible material using common joining methods. Yet, as shown in Figure 16, just can utilize the method of the present invention to make above-mentioned rayon core 1044 join by penetrating rayon between the nonwoven cover material 1046 of opposite sides of interlabial absorbent article to form joint 94. and forming.

As shown in FIG. 16, the absorbent rayon material 1044 is preferably pierced so that the first portion 1046A of the cover material 1046 engages the second portion of the cover material 1046. The means for engaging the covered absorbent material 1044 preferably includes a pair of cylindrical rolls - an embossing roll 110 and an anvil roll 112 . Cylindrical rollers 110 and 112 are similar to the rollers shown in FIG. 8 . As with the embodiment shown in FIG. 8, it is preferred that at least one of the rollers, ie, roller 110, have a relief pattern on its surface. Embossing roll 110 has a cylindrical surface 115 and a plurality of projections or pattern elements 116 extending outwardly from surface 115 . The relief and contact surface 118 on the pattern element 116 may be of any suitable shape. The sidewalls 119 of the pattern elements 116 preferably form an angle similar to that described for the roller 110 shown in FIG. 8 .

Rollers 110 and 112 operate in the same or similar manner as the apparatus shown in Figure 8 (including, but not limited to: range of surface velocity differences between the rolls, range of gap pressure between possibility of rollers and the replacement of rollers by other forms of gap formers).

In the embodiment of the device shown in FIG. 16, the relief pattern may also include a plurality of spaced apart pattern elements (or "tread element blocks") 116 with circular contact surfaces 118 . However, in the method embodiment shown in FIG. 16, the pattern elements 116 are arranged in a "half moon" shape. The pattern elements 116 are arranged alternately such that the junctions of two adjacent applications are located on opposite sides of the longitudinal axis A1 of the covering "string" of absorbent material.

The joining method shown in the figures penetrates the sheet of absorbent material 1044 and joins the first portion 1046A of the above-mentioned cover material 1046 with its second portion 1046B itself.

The illustrated embodiment of the absorbent article illustrates other advantages of the method of the present invention. The junctions 94 may be provided in a virtually infinite number of patterns. These joints 94 can be used to form products of virtually infinite geometries. The stiffness of the product is increased by the strands passing through the joints, thereby increasing the structural stability and forming the absorbent article. Such a line may be straight, curved, or partly straight and partly curved. Deep quilting indentations can be made to prevent liquid leakage or for an aesthetically pleasing appearance. The invention can also be used in production lines running at high speeds (eg, 700-1000 ft/min) and is not limited to certain patterns, as in sewing processes.

Figures 17 and 18 illustrate a sanitary napkin 1320 made using the method of the present invention with several different features. Figure 17 shows an absorbent article (extensible sanitary napkin 1320) in which several different steps can be performed simultaneously using the method of the present invention during the manufacture of the absorbent article. The sanitary napkin 1320 includes a main body portion 1322 . The main body portion 1322 includes a liquid permeable topsheet 1324; a liquid impermeable backsheet 1326 attached to the topsheet; These components can be joined in any manner that will allow the assembled sanitary napkin 1320 to be stretched. The sanitary napkin 1320 may include two end seals 1329 formed by fusing the topsheet and backsheet together. The sanitary napkin 1320 also has wings or panels 1330 extending from each longitudinal side edge of the main body portion 1322 thereof.

The sanitary napkin 1320 shown in Figure 17 has an absorbent core 1328 with regions 1334 of particulate material 1336 formed by the process described. As shown in Figure 17, regions 1334 comprising particulate material are separated by unformed bands 1338 arranged in the longitudinal and transverse directions. Additionally, deformable network regions may be formed on the topsheet 1324 and backsheet 1326 using the methods of the present invention. The term "deformable network region" is described in detail in US Patent No. 5,518,801, issued May 21, 1996 to Chappell et al., entitled "Web Materials Having Elastic Properties". Deformable network zones are provided on the topsheet 1324 and backsheet 1326 to impart extensibility to these components of the sanitary napkin. The unformed bands of the deformable network regions in the topsheet 1324 and backsheet 1326 can impart elastic properties to these extensible components. Forming the absorbent core 1328 as a particulate material allows the absorbent core 1328 to be in a form that does not interfere with the extensibility of the topsheet 1324 and backsheet 1326.

Depending on the pattern of deformable network regions formed, the topsheet 1324 and backsheet 1326 may be extensible in one direction, more than one direction, or all directions in the X-Y plane. In the embodiment shown in Figure 17, the sanitary napkin 1320 is extensible in both the longitudinal and transverse directions. The extensibility of the sanitary napkin shown in Figure 17 is preferably as described in U.S. Patent No. 5,611,790, issued March 18, 1997 to Osborn et al., entitled "Extensible Absorbent Article".

FIG. 17 shows that the methods described herein can also be used to impart extensibility to wings or panels 1330 . The flaps 1330 may be extensible in any of the directions described above for the topsheet and backsheet. It is also possible to make the elongation direction and elongation of the wings 1330 by passing the sanitary napkin 1320 through a different pattern of the pattern surface portion of the wing 1330 in contact with the pattern of the pattern surface portion of the main body portion of the absorbent article. The amount is different from the direction of elongation and the amount of elongation of the topsheet and backsheet. If two intermeshing rollers are used, the parts on the rollers used to make the wings extensible can be closer together; or, if the wings 1330 have fewer layers than the main body part 1322 , the two rollers can engage more deeply.

The method of the present invention may also be used to emboss and/or join together various components of the sanitary napkin. Figure 17 shows that the body-facing surface of the sanitary napkin 1320 can be embossed in the form of a number of melted joints 1340 . The fused joint 1340 can be made by forming a plurality of joints on the embossed surface of the means for forming the absorbent core 1328 into granular material. The bonding can optionally be heated if desired. Generally, in order to join the various components together, at least those components which are to be joined together should comprise at least some thermoplastic material. In other embodiments, it may be desirable for the embossed surface to be provided with joints that emboss only the body-facing surface of the sanitary napkin without forming the above-mentioned melted joints between the individual components.

Therefore, can utilize the method of the present invention to make absorbent core 1328 granular material, make topsheet 1324 and backsheet 1326 can extensible, make flap or guard panel 1330 can extensible, emboss and/or join them on each component. together, and the ends of the sanitary napkin 1320 are sealed. All these steps can be accomplished in one pass through the same apparatus as shown in the illustration. Additionally, as shown in Figure 18, the seam pattern can penetrate from the topsheet to the backsheet and provide structural integrity to the absorbent material by separating the topsheet and backsheet into zones. The hygroscopic material may include, for example, an airlaid heat bondable material. In such an embodiment, there is no need to utilize conventional binder fibers or powder binders to maintain the integrity of the material.

All of the aforementioned patents, patent applications (and any patents related thereto, and any corresponding published foreign patent applications) and publications mentioned throughout this specification are hereby incorporated by reference. However, it is not intended that any of these incorporated references disclose or teach the present invention.

While particular embodiments of the present invention have been disclosed and described, those of ordinary skill in the art will recognize that various changes and modifications can be made without departing from the spirit and scope of the invention.

Claims (4)

1, a kind of manufacturing is used for the method for composite web of hygroscopic material pipe of the molding of absorbent device, and described method comprises step:

(a) provide the hygroscopic material net width of cloth, the described hygroscopic material net width of cloth has first surface and opposing second surface;

(b) provide cladding material for the described hygroscopic material net width of cloth;

(c) cover first and second surfaces of the described hygroscopic material net width of cloth at least in part with described cladding material, the hygroscopic material net width of cloth that is capped with formation;

(d) the described hygroscopic material net width of cloth that is capped is formed the hygroscopic material pipe of not molding;

(e) with the part of the described hygroscopic material net of being covered with of described cladding material width of cloth first surface from body join the described hygroscopic material net of being covered with of described cladding material width of cloth second surface to relatively on the part of part, make hygroscopic material net amplitude shift position on the described engaging zones forming at least one joint simultaneously, form the composite web of the hygroscopic material pipe of molding.

2. the method for claim 1, wherein step (d) comprises the folding described hygroscopic material net width of cloth that is capped.

3. the method for claim 1, wherein said hygroscopic material comprises the moisture absorption foam.

4. the method for claim 1 also is included in from body engagement step (e) and before described hygroscopic material is formed a plurality of particulate steps.

Images