Method of making disposable panties with separable side seams

The present invention relates to a method of making disposable pants having separable seams. Such shorts have stiff sides and are put on by the wearer by inserting the legs into the opening and sliding them over the lower torso. Examples of this type t ciz-vz vr j vri op / <? Viviiv * v- η, νιπvrvvjy vil <

fi Τ- »o / -» </ »· \ r ·» -M zA / łkl ir I ho * H fi · »-» f ^ uzneoi ^ np, opiv / viij y ιυυ uui ljoij vii, jvaiiiOI az.vj shorts that can be used during menstruation with inserts such as tampons and sanitary napkins. The present invention relates in particular to disposable absorbent articles such as training shorts, garments with an insert (shorts or briefs) and the like having separable side seams.

Children and other persons who are not excreted wear absorbent articles to absorb urine and other body secretions. Absorbent products with rigid sides are popular when teaching children to use the toilet. This is because it is desirable to use an absorbent article that closely resembles a garment in appearance and feel, so that a learner is easily distinguishable from a diaper and can readily conform to the underwear. It is highly desirable that the rigid edges be separable allowing the absorbent material to be easily removed. This becomes especially important when the absorbent material is soiled and the soil may shift and smear as it moves down one or both legs.

An example of a disposable garment having separable side seams is described in U.S. US No. 4,205,678, which describes disposable underwear for use in teaching children to use the toilet or for use by incontinent persons having a material with a sticky bond that is weaker than the material itself, allowing it to be torn off along the seam for easier use. removal when the linen has been dirty.

Another disposable garment having separable side seams is described in US Patent No. US No. 4,355,425. The shorts are initially turned with the inner surface facing outward and the lateral edges conforming to each other. The transverse edges of the folded shorts are then glued, sewn, heat sealed or the like to form a kind of ruff or fine edge. The shorts are then turned over so that the ruff is on the inside of the prepared garment. In a particularly preferred embodiment, the transverse seams are combined by means of an ultrasonic welder with a cone-shaped closure which bonds the edges of the pants, furthermore keeping the seams in place. In U.S. Patent No. US No. 4,610,680 describes disposable training shorts that can be opened to facilitate removal of the wearer. In one embodiment, the disposable underwear has a tearing belt with a greater cohesive strength than the material of the shorts, the material around the waist of the shorts, or the material of the legs. By pulling this waist belt, the material of the shorts is cut or torn along their entire length, separating them in at least two places. In another version, the garment is made of overlapping pieces connected by snaps fixed on fastening straps that allow the disposable underwear to be opened in at least two places.

In U.S. Patent No. US No. 4,619,649 describes disposable training shorts having two separable side seams. The seams are made of overlapping surfaces of the pants material, which can be either sewn, heat-welded or glued together. If the seams are sewn together, the garment is pulled open by pulling the staple to open the seam from the waistband to the edge of the leg. If the seams are heat welded or glued, perforation is used to allow the seam to open.

In U.S. Patent No. US No. 4,747,846 discloses disposable training shorts with hand seams open at the side. The side seams are made by ultrasonic welding, thermal welding or gluing. The side seam may be in the form of an inward facing or an outwardly projecting flange or a delicate seam, or may be from overlapping materials. The side seams are separable by hand or alternatively the side seams may be provided with perforations on the side portions adjacent to the side seam.

170 375

A disposable garment having separable side seams is described in US Patent No. US No. 4,641,381 It has an inward flange or fine seam consisting of "a tie portion from about 1/16 inch to 1/8 inch wide and" a pressed portion wide from about 1/8 inch to 3/8 inch. an inch protruding orifice from about 3/16 inch to about 1/2 inch wide.

In U.S. Patent No. US No. 4,610,681 discloses training shorts with a ruff or fine seam extending inward.

Another example of a disposable detachable training shorts is described in US Patent No. 4,909,804. The seams of the disposable detachable training shorts were made with staples and directed inward. In the event of contamination of the linen with excrement, the linen is easily opened by pulling on the side seams, damaging the staples along the entire seam or material due to their fragility and may be torn in the vicinity of the side seam.

Another problem with disposable training pants is that they have to be manufactured in several different sizes to fit the dimensions of the different ages of children being toilet trained. Accordingly, in order to meet the needs of consumers, a manufacturer of disposable training pants must have several different sets of equipment for producing different sizes. Accordingly, it is highly desirable to have a solution which would allow the manufacturer to produce a single size disposable training pants to suit all consumers' needs for a very wide range of children's sizes. This requires the training shorts to fit snugly around the waistband and leg areas of smaller children, without falling, sagging, or sliding off the lower torso, while also fitting larger children without irritating the skin around the waist, legs or crotch. Therefore, the disposable training shorts should be elastically stretchable at the waist and at the user's legs, and the elastic elements must exhibit a high degree of stretchability.

Previous training shorts were elastically stretchable thanks to the elastic elements arranged in the elastic shorts, such that the waist opening and the leg openings were at least partially circumscribed by the elastic band. The flexible element method is described in US Pat. US Nos. 4,610,680, 4,335,425, 4,610,681, 4,641,381, 4909,804, and 4,960,414. '

Another method of flexibilizing disposable training pants is described in US Pat. US Nos. 4,490,464, 4,938,753 and 4,938,757. All these patents disclose a pant garment made by attaching separate extensible elements to the lateral edges of a substantial part of the garment.

Although training shorts made according to the above methods allow the absorbent material to adapt to small changes in size, training shorts made by these methods are limited in size fit because the elastic elements do not exhibit a high degree of stretch and because the side panels are not elastically stretchable. or have flexible elements of the side panels with fastening zones, which limit the flexibility of the flexible elements of the side lobes.

The object of the invention is to provide a process for the production of pants having separable tear-free seams, which can be produced more quickly and more easily than sewn or glued seams as has been the case hitherto, and which have a more underwear-like appearance and are less irritating than those produced so far. .

The essence of the method of manufacturing disposable pants having separable seams, in which a body is produced comprising a front part having longitudinal side faces, side pieces, a waist belt, the front part comprising polymer material at least in the longitudinal side faces and a rear part opposite the front part having longitudinal side surfaces, side members, waist belt, the rear portion comprising, at least in the longitudinal side faces, a polymeric material having a similar melting point to the polymeric material of the longitudinal side faces of the front part and crotch between the front part and the rear part, and the longitudinal side surfaces of the front part and the longitudinal side surfaces of the front part and the longitudinal side surfaces are overlapped. of the back part to form the first seam area and the second seam area: _ά mechanical energy, preferably, ultrasonic energy to the first seam region, sufficient to liquefy and thin, until cut, of the polymeric material in the first region and at the same time bond the polymeric material in an end region adjacent to the first region to form a first gapless seam containing a mass of molten polymeric material, which extends beyond the disposable pants 1.59 mm or less and forms a first leg opening and simultaneously fuses and cuts a portion of the second seam area by applying mechanical energy, preferably ultrasound energy, to the second seam area. sufficient to liquefy and thin to cut the polymeric material in the first area and simultaneously bond the polymeric material in the edge area adjacent to the first area to form a second tearless seam containing a mass of molten polymeric material which extends beyond the disposable garment 1.59 mm or less and forms a second waist opening surrounded by the front waistband and the back waistband, the second leg opening is separated from the first leg opening with the crotch portion.

Preferably, an inner layer is additionally produced and an outer layer attached to the inner layer, in a substantial part, the inner layer and the outer layer have similar melting points, so that the longitudinal side surfaces of the front part and the longitudinal side surfaces of the back part contain at least two layers of material. having similar melting points, preferably three or more layers of material having similar melting points.

Preferably, the material layers of the longitudinal side surfaces are made of the same material and preferably contain 100% non-woven polymeric material.

Preferably, an absorbent pad is attached to the inner layer, preferably the absorbent pad is a pad comprising a top layer and attached to the top layer, a backsheet and an absorbent core disposed between the top layer and backsheet.

Preferably, a first tearless seam and a second tearless seam are produced, each containing a mass of molten polymeric material forming the interface between the front portion and the rear portion.

The method of the invention comprises forming a body containing a polymer material and applying mechanical energy to the polymer material of the body to produce tearless seams comprising a thermoplastic formed polymer material extending beyond the garment by 1.6 mm or less. Preferably, the seam protrudes from the garment by about 0.8 mm or less.

Although the disposable garment produced by the method of the present invention may take various solutions, it preferably comprises an elasticized waistband, elasticized leg cuffs and an absorbent pad including a backsheet, a topsheet and an absorbent padding.

The subject matter of the invention is explained in more detail in an embodiment in the drawing, in which fig. 1 shows a perspective view of pants manufactured by the method according to the invention in the typical ready-to-use state in which they are worn by the user, fig. of the invention, with parts removed to show the underside of the structure, the surface is the top of the pants as seen from the viewer, fig. 3 - a sectional view of the principal part shown in Fig. 2 along line 3-3 in Fig. 2, Fig. 4 - a sectional view of the principal part in Fig. 2 along line 4-4 in Fig. 2, Fig. 5 - in a view in view of the principal part in Fig. 2 folded in the crotch portion with the front part coinciding with the rear part, Fig. 5A is a sectional view of the principal part shown in Fig. 5 along the line 5A-5A in Fig. 5, fig. 6 - in a schematic top side view of an ultrasonic device as used for the manufacture6

170 Fig. 6A - a fragmentary view of the device shown in Fig. 6 along the line 6A-6A in Fig. 6, Figs. 7 and 7A show, in fragmentary views, cross-sections of the longitudinal side surface of other variants of the garment made by the method. according to the present invention, fig. 8 is a simplified perspective view of a vacuum web retainer while mechanically stretching a body portion using grooved crimping rollers, Fig. 8A - a simplified view of a section along line 8A-8A in Fig. 8 showing how the vacuum rollers have been used for the material of the main part to be bent by the lower, most grooved rollers, fig. 8B is a greatly enlarged view of the inset 8B shown in Fig. 8 showing the degree of crimping of the grooved rollers and elsewhere as a portion of the "zero-tension stretched body laminate passes therebetween, Fig. 9 - a simplified perspective view of another web retention method. as may be used during the staging process, Fig. 9A - in a greatly enlarged view, a sectional view of the insert 9A shown in Fig. 9 along the center line connection of the uppermost grooved shafts and the lowest grooved shafts, Fig. 10 is a simplified view of a section of the main part of pants made according to the present invention in another embodiment, and Fig. 11 is a simplified view of a cross section of the main part of a garment according to the invention, in another embodiment.

A disposable garment is one that must be removed after use (that is, it is not intended to be washed or otherwise preserved or reused). Disposable garments can be equipped with an absorbing pad, which is placed in the immediate vicinity of the user's body to absorb various secretions excreted by the body. The disposable pants 20 made in accordance with the invention are shown in Fig. 1. The training shorts 20 in Fig. 1 they include a main part 14, a cut-free stitching 10 and an absorbent core 22.

Figure 2 shows a cut-away perspective view of the disposable pants 20 of Figure 1 from the front side 56 and the rear part 58 of the base part 14 joined together. The main part 14 is a preferably symmetrical modified hourglass shape. Main portion 14 includes at least a front portion 56, a rear portion 58, a crotch portion 57, and longitudinal side surfaces 88, and includes a polymeric material at least in the longitudinal side surfaces 88 to facilitate bonding, a process described in more detail below. The absorbing pad 22 is attached to the base part 14.

As shown in Fig. 2, a preferred embodiment of the main part 14 comprises an outer layer 48 and an inner layer 46 with side panel elastic members 90, waist belt elastic portions 76 and elastic fibers 105 interposed between the inner layer 46 and the outer layer 48.

The outer layer 48 is that part of the body 14 that forms the outer surface of the disposable training pants 20 as viewed from the wearer's side. The outer layer 48 is compliant, soft to the touch, and non-irritating to the wearer's skin. A suitable outer layer can be made of many different materials, such as plastic films, woven or non-woven materials of natural fibers (such as wool or cotton fibers), synthetic fibers (such as polyester or polypropylene fibers), or mixtures of natural and artificial fibers. . Preferably, the outer layer 48 is hydrophobic and is made of a material containing a significant proportion of thermoplastic fibers, typically 50% or more, preferably 100%. Preferably, the outer layer is a carded non-woven polypropylene fiber material. The corresponding Senes 6700 Nonwoven outer layer is manufactured by Scott Nonwovens in Landisville, NJ.

The inner layer 46 is that part of the body 14 which forms the inner surface of the disposable training pants 20 and which makes contact with at least the waist and legs of the wearer. The inner layer is also pressure sensitive, soft to the touch and non-irritating to the wearer's skin. Suitable inner layer 46

170 The 375 can be made of many different materials, such as plastic films, woven or non-woven materials of natural fibers (such as wool or cotton fibers), synthetic fibers (such as polyester or polypropylene fibers), or mixtures of natural and artificial fibers. Preferably, the inner layer 46 is made of a material containing a significant proportion of thermoplastic fibers, typically 50% or more, preferably 100%. Preferably, the inner layer is also a carded non-woven polypropylene fiber material. More preferably, the inner layer 46 is made of the same material as the outer layer 48. A corresponding Series 6700 Nonwoven inner layer is manufactured by Scott Nonwovens of Landisville, NJ.

The inner layer 46 is preferably located adjacent to the outer layer 481, preferably joined to it by generally known (not shown) binders. For example, the inner layer 46 may be joined to the outer layer 48 by a unitary adhesive layer, the adhesive layer having a pattern or area of ​​discrete lines, spirals, or adhesive dots. Adhesives found to be of sufficient quality are manufactured by Findley Adhesives of Wisconsin and sold under the name Findley 2031. Alternatively, the binder may be heat setting, pressure setting, ultrasonic bonding, mechanical bonding or any other known method. a method or a combination thereof. The term "combined as used herein" means an arrangement in which one item is attached directly to another item by attaching that item to another item, and an arrangement in which an item is indirectly attached to another item by attaching that item to the intermediate member (s). which in turn are attached to another element.

In a preferred embodiment, the inner layer 46 and the outer layer 48 are indirectly connected to each other by direct coupling thereof to the panel elastic members 90, waist belt elastic portions 76 and the elastic fibers 105, and are connected directly to each other at points protruding beyond the panel elastic members 90. elastic parts 76 of the waist belt and elastic fibers 105.

In a preferred embodiment, at least a portion of the inner layer 46 and the outer layer 48 of the base portion are mechanically stretched to provide a "zero stress" stretched laminate that forms the flexible side panels 30. Thus, the inner layer 46 and the outer layer 48 are preferably elongate, most preferably stretchable but not necessarily elastomeric, such that the inner layer and outer layer 46, 48 extend when mechanically stretched such that they remain at least partially elongated and do not return. completely to its previously unchanged form. In a preferred embodiment, the inner layer 46 and the outer layer 48 can be mechanically stretched without tearing or breaking. Thus, the inner and outer layers 46, 48 preferably have a low strength transverse to the body.

The body 14 of the disposable training pants 20 preferably further includes elasticated cuffs 32 of the legs to better retain liquids and other body fluids. Each of the elasticized cuff 32 of the legs may have various solutions to reduce leakage of body secretions in the leg area. (The leg cuff may be and is sometimes referred to as a leg band, hem, hem, or elasticated cuff.) In the US patent specification No. 3,860,003 entitled "Shrink Rim for Disposable Diaper" describes a disposable diaper having a shrink leg cuff (sealing cuff). In U.S. Patent No. US No. 4,909,803 entitled "Disposable Absorbent Element Having Elasticized Hems," describes a disposable diaper having "raised elasticized hem (leg welts) to increase the seal around the legs.

In U.S. Patent No. US No. 4,695,278 entitled "Absorbent Article Having Double Cuffs" describes a disposable diaper having double cuffs including a sealing cuff and a leg welt. In U.S. Patent No. US No. 4,704,115, entitled "Disposable contaminant-absorbing garment is disclosed."

170 375 a disposable diaper or an absorbent garment having edge grooves to prevent leakage, made to retain spilling liquid in the garment. Although each elasticized cuff 32 may be made similar to a leg band, hem, hem, or elastic cuff as described above, it is preferred that each elasticized cuff 32 comprises at least a panel 104 with one or more elastic fibers 105.

The body portion 14 of the disposable training shorts 20 preferably further comprises an elasticated waistband 34 adjacent the end edge 64 of the disposable training shorts 20 at least in the rear portion 58, and more preferably includes an elasticated waistband 34 disposed in both the front portion 56 and the rear portion 58. The elasticated waistband 34 adjacent the end edge 64 of the disposable training pants 20 is that part of the garment to be placed around the wearer's waist. The elasticized waist belt 34 is that element that provides a certain area cover, contacts the wearer's waist, and is elastically stretchable at most in the transverse direction so that it fits the wearer's waist and dynamically adjusts to the wearer's waist to provide a better fit. Thus, the waistband of the disposable training pants 20 extends from the end of the edge 64 of the disposable training pants 20 to at least the waist edge 83 of the absorbent core 28. While the elasticated waist belt 34 may include a separate piece attached to the body 14 of the disposable training shorts 20, the belt preferably extends other parts of the disposable training shorts 20, such as the inner layer 46, outer layer 48 or any combination of these parts and associated material. elastomeric. Optionally, the topsheet 24 and the backsheet 26 of the absorbent core 22 may extend beyond the absorbent core and include an elastomeric material bonded thereto to form an elasticized waistband. Disposable training shorts are often constructed with two elasticized waist belts, one at the front 56 and one at the rear 58. The disposable training shorts 20 have at least an elasticated waistband 34 disposed at least in the center 68 of the back portion 58. Preferably, as shown in Fig. 2, a second elasticized waistband is provided in the front portion 56. Preferably both elasticized waistbands 34 are positioned between the elasticated waistband 34 side flaps 30.

The elasticized waist belt 34 can be constructed in many different ways, including those described with the elasticized side members. In the preferred embodiment shown in Fig. 2, the elasticated waist belt 34 includes an elasticized waist belt member 76 positioned between the inner layer 46 and the outer layer 48 and is connected to one or both of the inner 46 and outer layers 48 to join the front portion 56 and the back portion 58 of disposable training pants 20. An example of such an elasticated waist belt that can be used herein is the elasticized waist belt disclosed in US Patent 4,466,314. US No. 4,515,595 entitled "Disposable Diaper With Elastic Shrink Waist Belts."

Any known elastomeric material may be used in the shorts of the present invention as the waist belt elastic 76. Examples of suitable elastomeric materials include elastomeric films, elastomeric foams such as polyurethane foams or cross-linked natural rubber foams, elastomeric cloth upholstery, elastomeric films such as heat shrinkable elastomerics, elastomeric film laminates such as laminates of heat shrinkable elastomeric films and elastic, elastomeric, stretchable laminates such as as "zero-tension" tensile laminates as described below or mechanically stretched pre-tension stretch laminates, elastic fibers made of rubber, LYCRA or other materials. In a preferred embodiment, waist belt elastic member 76 comprises a heat shrinkable elastomeric film.

Alternatively, the elasticated waistbands 34 and the elasticated side panels 30 can be made by attaching a single piece of elastomeric material to disposable training shorts 20 in both side panels 72 and the center zone 68 of the portion.

170 375 of the rear portion 58 and the attachment of a single piece of elastomeric material to the disposable training shorts 20 in both side panels 72 and the center zone 68 of the front portion 56. Thus, the elasticized waistband 34 and the elasticized side panels 30 can be made of the same piece of material to form a seamless pattern.

In a preferred example, the disposable pants also include elasticized side panels 30 located at the front 56 and rear 58. (As used herein, the term "positioned" means that the item (s) of the disposable pants is formed / connected and positioned at a specific location. or items as a homogeneous structure with other items of disposable pants or as a separate item combined with other items of disposable pants). The elasticized side panels 30 provide elastic stretchability which provides a more comfortable and snug fit by immediately adjusting the disposable pants to the wearer and maintaining this good fit all the time the disposable pants are filled with exudate, as the elasticized side panels of the disposable pants allow for stretching and shrinkage of the sides of disposable shorts. While the disposable training shorts 20 preferably include elasticized side panels 30 in both front 56 and back parts 58, the training shorts 20 may optionally include elasticized panels 30 in only the front 56 or only the back 58.

The flexible side panels 30 of the disposable training shorts 20 can be constructed in many different ways. An example of a disposable product with an elastic material positioned in the side panels is the disposable product disclosed in US Pat. US Amryki No. 4 857 067 entitled "Disposable diaper with pleated side panels. The flexible side panels 30 may optionally be constructed in a variety of other ways. For example, U.S. Patent No. US No. 4,381,781 describes an absorbent article having a flexible waist, in which an elastic element is positioned in an opening in the top and bottom layers of the absorbent article such that the stretching of the elastic element is not constrained by inelastic materials. Although it is stated in the description that it is very important to remove the top and bottom parts of the absorbent article where they are in contact with the elastic element, sufficient elastic properties can nevertheless be obtained also when only one or none of the contacts are removed. part of the top and bottom layers of the absorbent product, especially when those portions of the absorbent article web containing the elastic element will be subjected to gradual mechanical stretching by means of the procedure described below.

Another variant of an absorbent article having flexible side panels is described in US Patent No. US No. 4,938,753. This specification describes a pant garment comprising stretchable side panels formed by the attachment of separate stretchable members to the side edges of a body of the garment. Thus, the flexible side panels 30 may comprise a separate, elastically stretchable material or laminate attached to the base portion 14. As shown in Figures 1 and 2, each flexible side panel 30 preferably comprises a flexible panel member 90 connected thereto.

As shown in Fig. 2, each side panel 72 includes that portion of the principal portion 14 that extends transversely outward from and along the center zone 68 of the principal portion 14 to the longitudinal side surface 88 of the principal portion 14. The side flap 72 typically extends longitudinally from the end edge 64 of the base 14 to those portions of the longitudinal edge 62 of the base 14 that define the leg opening (this portion of the longitudinal edge 62 is designated as the leg opening edge 106). In a preferred embodiment, each side portion is formed by portions of the inner layer 46 and outer layer 48 that extend beyond the central zone 68 of the base portion 14.

In a preferred embodiment, the elastic members 90 of the panels are connected to the disposable training shorts 20 by side panels 72, preferably between the inner layer 46 and the outer layer 48, such that the elastic members 90 allow the elasticized panels 30 to elastically extend laterally (laterally elastically stretchable). . As used herein, the term "elastically stretchable" means a segment or portion of a substantial portion that extends in at least one direction (preferably lateral for

170 375 waist panels and belts) when tensile forces (typical lateral tensile forces of the side portions and waistbands) are applied and returns to the previous dimension when the tensile forces are removed. Typically, a preferred elastomeric material shrinks to at least 75% of its previous size within 5 seconds or less after stretching and immediate removal of the tensile force (i.e., "fast elastic").

The flexible panel members 90 may be effectively connected to the side panels 72 in a variety of ways. For example, the flexible members 90 may be "operatively connected in an elastic contraction fashion so that the flexible member 90 of the airfoil moves closer to or attracts the side panel? 2. (A more detailed description of how elastomeric materials can be elastically shrink attached can be found in US Patent No. No. 3,860,003 and in U.S. Patent No. 3,860,000. US No. 408,301. For example, flexible members 90 may be connected to the side panel 72 in a flexible shrinkage manner by extending the panel member 90 laterally, joining the flexible member 90 to one or both layers, the inner layer 46 and the outer layer 48, and allowing the flexible member to be 90 reaching a contracted or free state.

Alternatively, the flexible element 90 may be connected freely and then contracted. For example, flexible element 90 can be made of materials that do not shrink on their own and only become flexible when appropriately treated, such as heated. Examples of such materials are described in US Patent No. US In U.S. Patent No. 3,819,401 and in U.S. Patent No. US No. 3,912,565. A more detailed description of how a flexible heat shrink member is used is found in U.S. Patent No. US No. 4,515,595. The flexible panel element 90 and other parts (e.g., inner layer 46, outer layer 48, cover layer 24, backsheet 26, etc.) are usually joined together in a tensionless condition. The laminate is then heated (with hot air) and allows the flexible side part to return to its relaxed or shrunken state.

In a particularly preferred example, the flexible element 90 may be connected to the side panel 72 by connecting the element 90 to the inner layer 46, the outer layer 48 or both while the flexible element 90 of the airfoil remains completely tensionless. At least a portion of the resultant composite elastomeric laminate containing the flexible member 90 is mechanically stretched to provide permanent elongation of the inner layer and outer layer (non-elastic portions) of the laminate. The composite elastomeric laminate is then allowed to return to its fully stress-free state. The flexible sheet was thus transformed into a "zero tension stretch laminate." (Alternatively, the flexible element of the airfoil may be joined under tension and then mechanically stretched, however this is not as preferred as "zero tension stretch laminate). As used herein, the term "zero-tension stretch laminate" means a laminate comprising at least two layers of material that are bonded together along at least a portion of their contact surfaces in a completely unstressed ("zero-tension) state - one of the layers includes stretchable and elastomeric material (that is, fully recovering to its pre-stress dimensions after the tensile force is removed) and the second layer is stretchable (but not necessarily elastomeric) such that the second layer remains permanently stretched at least to some extent when the tensile force is removed, and is not returns completely to its original undistorted state. The resulting "zero-tension laminate" thus becomes elastically stretchable, at least up to the initial stretch state. Examples of such "zero tension stretch laminates are disclosed in US Pat. US No. 2,075,189, No. 3,025,199, No. 4,107,364, No. 4209,563 and No. 4,834,741.

Particularly advantageous methods and devices for producing "zero-tension stretch laminates of the inner and outer ply and an elastomeric element interposed therebetween provide intermeshing grooved rollers for mechanically stretching the components." Discussion of appropriate apparatuses and methods of mechanical stretching

170 375 pieces of disposable diaper are included in the previously cited US Pat. US No. 4,107,3641 No. 4,834,741. Particularly preferred methods and devices are described in US patent application no. US No. 07/662536 entitled "Improved Method and Apparatus for Gradually Stretching" Zero-Tension Laminate Webs to Make It Flexible, and in US Patent Application No. US No. 07/662543 entitled "Improved Method and Apparatus for Gradually Stretching" a Zero Tension Laminate Web to Give it Flexibility without Breaking the Web.

Details of a particularly preferred gradual stretching device that can be used to form elasticized "zero-tension stretch laminate panels" are shown in Fig. 8. The fully assembled body web 810 containing the "zero-tension stretch laminate" panels is passed through the step-stretching device.

Referring to Fig. 8, the timing of the advance of the web 810 of the body portion containing the fully stress-free elastic elements of the airfoil (elastomeric inserts 804) is such that the fully stress-free elastomeric inserts 804 accurately coincide with the grooved or grooved segments 824 located on the upper grooved rollers 825 when body web 810 extends between segments 824 of upper grooved rollers 825 and lower grooved or grooved rollers 821.

While the exact spacing, distances, and depths of the corresponding grooves on the upper and lower grooved rollers vary depending upon factors such as the desired degree of flexibility in the "zero-tension stretch laminate" portion, the most preferred embodiment used a crest-to-apex distance of about 3 , 8 mm, groove angle, measured at apex of approximately 12 degrees, and groove depth, measured from crest to bottom, approximately 7.6 mm. The crest radius of each groove on the above-mentioned grooved rollers is typically about 0.25 mm, while the bottom radius of the groove between adjacent grooves is typically about 1 mm. When grooved shafts are positioned like this, that their opposing crests of grooves overlap to a depth of from about 3.8 mm to about 4.45 mm, a laminate web with good elastic properties is obtained comprising a 0.76-1.27 mm thick foam elastomer inlay attached to its opposing positions surfaces to the inner non-woven layer and outer non-woven layer having a starting weight in the range of about 23.9 to 35.8 grams per square meter and including polypropylene fibers.

The degree of overlapping of opposing ridges on the aforementioned grooved rollers may of course be adjusted as desired to provide more or less elongation of the resulting "zero-tension stretch laminate" web. Given the above-mentioned roll geometry and laminate web construction, a suitable range for variation in the depth of overlapping of the roll crests is from about 1.3 mm to about 5.7 mm.

As seen in Fig. 8A, the idler rolls 872, 874 cause the web 810 to sufficiently tightly wrap the lowermost rollers to cover the active vacuum openings 822 (shown in Fig. 8) located in close proximity to each group of grooves 823 on the lower rollers 821. Vacuum openings 822, so positioned to effectively meet grooved segments 824 located on upper grooved shafts 825, are connected within shafts 821 to a pair of vacuum lines 826, thereby sucking the web 810 of a substantial portion while operating the web of grooved segments 824 of the upper grooved rollers 825.

To minimize deposition of the adhesive used to bond the elastomeric inserts 804 to the inner web layer 805 and the outer web layer 806 or the adhesive used to bond corresponding portions of the inner layer and outer web layer, grooved segments 824 located on the upper grooved rollers 825 and continuous grooves 823 on lower shafts 821 should be made of either a low friction material such that as TEFLON or coated with a self-lubricating low friction material such as Permalon No. 503 spray supplied by Micto Surface Corporation of Morris, Illinois.

170 375

The vacuum openings 822 on the lower rollers 821 are preferably covered with a 2.3 mm mesh honeycomb porous material 844 to provide support for the pieces of web 810 of the base portion under vacuum and to provide a good adhesive surface for the webs! lateral skid or transverse shift when the web is subjected to a vacuum.

Under optimal conditions, the amount of gradual stretching to which the "zero-stress side portions containing the elastomeric inserts 804 may be subjected is determined by the depth of interaction between the grooves on the grooved segments 824 of the upper grooved rollers 825 and the continuous grooves 823 on the lower rollers 821). that the optimum degree of stretching is not achieved without good protection of the stretched laminate web from slipping or shrinking in a direction parallel to the stretching direction of the web as it passes between the grooved rollers holding it. Therefore, in the most preferred embodiment, the step-stretching operation of the web is then performed , when the outermost portions of all three layers making up the "zero-tension" stretch laminate are held, as generally shown in the cross-section of Fig. 8B, to completely prevent slippage or shrinkage of the parts making up the "zero-tension" stretch laminate in a direction parallel to the stretching direction of the web as it passes between the properly positioned grooved support rollers.

However, the present invention can also advantageously be used by holding only the tensile layer or layers of the composite, that is, it is not absolutely necessary that the outermost portion of the elastomeric insert also be held during the gradual stretching operation. In the latter case, the elongate or extensible layer or layers are still permanently elongated during the gradual stretching process, but the bulging in the z-direction of the thus produced "zero-tension stretch laminate web" may be somewhat less after the tensile stress has been removed. This is because during such a process, a lower initial stress is exerted on the elastomeric pad. Consequently, when it returns to its undeformed state, it shrinks less.

"The zero-tension stretch laminate of the type described above may also exhibit some degree of non-uniformly localized stresses in the elongate web or webs, particularly in areas immediately adjacent to the opposing edges of the elastomeric inserts. In the case of an opaque polymer web of the inner layer or outer layer, these non-uniformly stressed portions may become so thin that they even become transparent even though no cracks occur. In such cases, the functionality (e.g., impermeability) of the "zero-tension" stretch laminate web portion is not reduced. Variants of the latter type are usually used in situations where the stretchable laminate parts with zero stress in the finished garment are not visible due to the structure or condition of the garment, or if they are visible, their appearance is of no importance to the wearer of the garment.

In yet another embodiment, even a breakage of one or more elongate non-elastic webs may not interfere with the intended use of the finished "zero-tension stretch laminate web" (for example, when a portion of the top or bottom layer of the absorbent body is a component of the laminate web, the breakage of the top layer or bottom web would not deprives it of its functionality in accordance with its intended purpose, as long as another layer in the laminate web provides this function in the finished product). For example, some degree of fracture in the elongate bottom web layer will not render the web impervious to parts if the elastomeric inserts are made of a fluid impermeable material. This is especially true of such a variation of "zero-tension stretch laminate web" in which the layers in question are continuously connected, since the relatively close adhesion of one layer to another after gradual stretching makes it difficult to detect this type of damage to the wearer of disposable pants.

170 375

Suction forces applied to the principal web 810 shown in Figs. 8-8B through vacuum openings 822 exerted through the honeycomb porous material 844 effectively protect portions of the principal web 810 containing fully annealed elastoQA / 1 ...

The meric inserts 804 are forced to wrench or contract in a transverse direction as they pass between the meshed portions of the continuous grooves 823 on the lower grooved rollers 821 and the grooved segments 824 on the upper grooved rollers 825.

Since portions of the "zero-tension" stretch laminate web 810 of the body containing the fully relaxed elastomeric inserts 804 are laterally restrained during subsequent stretching operations of the web, all parts of the "zero-tension" stretch laminate web¹The stretched laminate web between the points of restraint are effectively subjected to uniform gradual stretching as the web passes between the receiving portions of the continuous grooves 823 on the lower grooved rollers 821 and the grooved segments 824 on the upper grooved rollers 825.

Not only does this maximize the efficiency of the gradual stretching process by forcing the greatest degree of elongation during the stretching operation of the extensible inner layer and the outer web layer to which the elastomeric inserts are attached, but also effectively prevents disproportionately high stress on the inner layer and / or outer web layer. to which they are attached at points immediately adjacent to the opposing edge portions of the edges of the elastomeric inserts.

Figure 9 shows another possible system for gradual web stretching. In the web stretching system shown in FIG. 9, a pair of resiliently compressible rollers 940 is mounted adjacent each side of the grooved segments 924 of the upper grooved rollers 925. The compressible disks 940 are of a sufficiently large diameter to hold the web 910 of the base firmly and press it firmly against the corresponding unremoved portions of the lower grooved rollers 921 as shown in the cross section in Fig. 9A. As with the vacuum openings and the honeycomb porous material in the example of Fig. 8, the bonding effect produced by the compressible rollers 940 and the corresponding non-grooved portions of the lower grooved rollers 921 substantially prevents the portion of the web 910 of the body containing elastomeric inserts 804 from shrinking in a direction parallel to the stretching direction as the web passes between the retaining grooved rollers. An example according to Fig. 9 it can be applied with equal ease to laminate structures composed of webs which are permeable or not permeable to air.

As will be recognized by those skilled in the art, the aforementioned methods may be used alone or in combination with others to produce the advantages of the "zero-tension" portion of the stretch laminate base described herein.

It is clear from the description set forth herein that lesser improved methods and devices can advantageously be used to produce a wide variety of disposable garments containing one or more separate "zero-tension" parts.¹¹ stretch laminate web or a garment entirely made of it.

It has also been found that although the intermeshing grooved rollers shown in the accompanying drawings have grooves exactly parallel to each other, the present invention can be used with equal ease using grooved rollers not all of which are parallel to each other. Moreover, the grooves on a pair of grooved rollers need not necessarily be parallel to the device or to a direction perpendicular to the device. For example, if it is desired that a portion of the waistband or a portion of a legband of a disposable garment produced using the "zero-tension" technology described herein,¹¹ the stretch laminate takes the form of a curved line, the notch teeth on both grooved rollers used to gradually stretch the "zero-tension" portion of the stretch laminate web can be positioned in the desired curvilinear configuration for flexibility along a curved contour and not along a straight line.

170 375

It has also been found that although the preferred methods described herein employ intermeshing cylindrical grooved rollers, stretching of the web may also be accomplished by discontinuous embossing using interlocking plates to gradually stretch a portion of the "zero-tension" stretch laminate web or other product. In the latter case, the only condition is that the parts of the "zero-tension" stretch laminate web to be stretched are properly secured by suitable vacuum or securing elements before the intermeshing plates exert sufficient force on the web causing the web to slip or shrink in a direction parallel to the stretching direction.

The flexible panel members 90 may be connected to the inner layer 46, the outer layer 48, or both, either pointwise or substantially continuously. As used herein, "point-bonded" laminate web means a laminate web in which the layers are pre-bonded to one another by discontinuous, separated, discrete points, or a laminate web in which the layers are disconnected from one another in discontinuous, separated areas. Conversely, an "substantially continuously" connected laminate web means a laminate web in which the layers are pre-connected to each other in a substantially continuous manner through the contact surfaces. An intermittent bonding method is generally preferred for a "zero-tension" laminate web, in those cases where the substantially inelastic web in the laminate is relatively elongate or pull-out without breaking, and where a high degree of axial bulging from the laminate produced is desired. Continuous bonding is generally preferred for a "zero-tension" laminate web, in those cases where the high degree of z-bulging of the laminate produced is not critical, and when one or more relatively inelastic webs in the laminate are difficult to elongate or pull out without causing it. breaking up. In the latter case, the substantially continuous bonding method keeps all the layers of the laminate in relatively close contact with each other after the stretching operation. Thus, if one or more relatively inelastic webs are damaged to the point of breaking, the relatively close contact of the damaged portions of the relatively inelastic web or webs with the elastomeric layer prevents the user from noticing any damage that has resulted. Assuming that breaking the relatively inelastic web or webs does not deprive it of its intended functionality (e.g., impermeability), damage to the relatively inelastic web or webs during the staging operation is generally not considered to be detrimental to the final product.

Thus, an unexpected advantage that derives from the use of a continuous bonding of a particularly preferred "zero-tension" stretch laminate web allows the manufacturer of disposable garments to select from a relatively wide range of relatively inelastic materials that can be successfully used in laminates suitable for making pants by the method of the present invention. invention. In fact, this allows relatively inelastic webs to be used in "zero-tension" stretch laminates, which are usually not considered to be extensible to any significant degree. Accordingly, unless otherwise stated, the term "stretchable" as used herein is not intended to exclude relatively inelastic webs that are thinned or damaged during the staggering operation.

In a preferred embodiment of the present invention, the flexible panel element 90 may be continuously connected to the inner layer 46 and the outer layer 48 by an adhesive. An adhesive applicator can be used to apply a homogeneous and continuous layer of adhesive to the inner layer 46 and / and the outer layer 48 at those predetermined locations where the tensionless elastic element 90 will be positioned. In a particularly preferred example, the adhesive used is stretchable and the adhesive applicator comprises a dispensing blow system.

One such meltblown applicator that has proven particularly suitable for producing a "zero-tension continuously bonded stretch laminate web is the Model No. GM-50-2-1-GH melt blown applicator available from JandM Laboratories in Gainesville, Georgia." . This device employs a die with 0.8 holes per mm of length measured in the perpendicular machine direction, each hole having a diameter of approximately 0.5 mm. Findley H-2247 hot melt adhesive, available from Findley Athesive, Elm Grove,

170 375

Winconscin is preferably heated to about 171 ° C and is applied to the inner layer and / or outer layer at about 0.012-0.016 milligrams per square millimeter. Compressed hot air at a temperature of about 218 ° C and a pressure of about 345 kPa is supplied through additional holes in the glue-dispensing nozzle to guide the threads of glue evenly during application.

Alternatively, the flexible member 90 and other components comprising the "zero-tensioned parts of the disposable training pants 20 may be continuously or punctually bonded together by cold adhesives, heat sealing, pressure bonding, ultrasonic welding, dynamic-mechanical bonding or any other technique. by a known method in this respect.

The flexible airfoil element 90 can be given a number of different sizes, shapes, and configurations, and can be made of a variety of materials. For example, the flexible panels 30 may be formed of one or more flexible elements 90 connected to the individual panels 72; flexible elements can be of different width and length; optionally, the elastic elements of the panels may include relatively narrow strips of elastomeric material or elastomeric inserts with larger surfaces. An elastomeric material that has proved particularly suitable for use as a flexible panel element 90 (particularly for a "zero-tension stretch laminate)" is an elastomeric foam having a tensile strength to break of at least about 400% and a tensile force of at least 7 grams per mm of sample width at 50%. elongation compared to its unloaded length. Examples of elastomeric foams which have proved suitable for use as flexible panel members are: a cross-linked natural rubber foam of about 0.89 mm in length and a density of 0.214 g / cm3, available from Fulflex INc. from Midletown, Rhode Istand, or from Ludlow Composites Corporation of Fremont Ohio, or polyurethane foams about 2.03 mm thick and about 0.033 g / cm 2 density³, available from Bridhestone of Yokokohama, Japan and sold under the trade name Bndgestone SG polyurethane foam, or available from General Foam of Paramus, New Jersey and sold under the trade name Polyurethane Foam No. 40310. Other suitable elastomeric materials for use as elastic members 90 are "live synthetic or natural rubber, other synthetic or natural rubber foams, elastomeric films (including heat-shrinkable elastomeric films), elastomeric bookbinding cloths, elastomeric woven and non-woven materials, elastomeric composites such as such as nonwoven elastomeric laminates or the like.

As shown in Fig. 1, the flexible element 90 includes an insert of elastomeric material (elastomeric insert) which preferably extends the entire length of the panel 72 at the front 56 and rear portions 58. Thus, the flexible element 90 preferably extends the entire length of the panel 72. from the end edge 64 of the main part 14 to the edge 106 of the leg opening of the panel 72. The length and width of the elastic elements 90 depend on the functional design of the garment. Thus, the flexible element 90 of the airfoil preferably extends the entire length of the flap 72, although the flexible element 90 may only extend a portion of the length of the flap 72.

It has been found that the tensile characteristics including tensile forces, tensile modulus, possible stretching (elongation) and contraction forces, elastic creep, elastic hysteresis; the shrinkage rate of the flexible sheets 30 is very important for the properties of both the flexible sheets 30 and the disposable garment. The stretch characteristics inform the user of the total possible "elongation in use". An elasticized flap with a relatively high modulus of elasticity may leave red marks on the wearer's skin, while a relatively low modulus of elasticity may lead to the garment sagging / sliding off the wearer. Elastic flaps 30 exhibiting too little maximum attainable elongation may not allow the desired level of fit to be achieved and may make the disposable garment inconvenient and difficult to use. Disposable confection with elasticized flaps with low shrink force or low elastic creep or hysteresis of elasticity may not stay on the user and show

170 375 has a tendency to hang / slide off the user, leading to a bad fit and poor tightness.

It has been found that the characteristics of the tensile force and the tensile modulus of the flexible 30 kO> r7 vets fall within the ranges Tensile force in terms of jjiulc? O \ s iwi / _j j imv ii j ι ν,? Ί. > ji γ »» voio ii j Vn Λ, ιιινι v jh νιι · * _ / iivi a \ J vti ιννι Ł.jjtinv nj

19.7-118.1 grams per cm in length. It is preferred that these tensile forces are generated at elongations of from about 20% to about 300%.

The maximum possible stretch determines the maximum amount of material available in the elasticized flaps for reversible stretching according to the wearer's body during use of the pants. Thus. the amount of stretch available refers to the maximum amount of elongation that is possible for the garment to conform to the wearer, in addition to the maximum amount of recoverable stretch to allow the garment to conform to the user's body. The maximum achievable stretch is calculated from the equation: (maximum circumference of the garment - circumference of the user): (circumference of the user) X 100. The minimum amount of possible stretch necessary in a disposable garment with elastic side lobes is preferably at least about 35% for garments of the "one-size" type -All that fits children weighing from about 10 kg to about 17 kg.

The magnitude of the retaining contraction force (tension) exerted by the elasticized flaps on the user is an important feature of these elasticized side flaps. An elasticized flap with insufficient contraction force may cause the worn and filled disposable shorts to drop. Conversely, too much contraction force may reduce the wearer's sense of comfort and cause blisters on the skin. Shrinkage force is measured as force per unit length and is generated when an elastomeric composite is no longer stretched. In a preferred embodiment, the contraction force of the elasticized panels is preferably at least about 19.7 grams / cm at 10% elongation (10% elongation requires the specimen to be stretched to a length 1.1 greater than the original length).

Among the tensile-stretching properties, typical elastomeric materials exhibit a hysteresis loop. This means, for a given stretch, that the force (tensile force) required to axially stretch the clastomeric material is greater than the force (contraction force) that the elastomeric material exerts after contracting to its pre-stretching state. The first curve can be called "load curve" and the second curve can be called "non-load curve". “The load tensile force (tensile force) is felt by the user or the parents when the elasticized sheets are stretched as the garment is put on by the user. The user himself, after putting on the clothes, "feels" better the non-load contraction force. Thus, the hysteresis loss should not be too great, so that the contraction force is not too low, which would cause the garment to sag / slide off the wearer.

All elastomeric materials subjected to constant stress-tension exhibit a reduction in forces (for example, elastic creep) over time. Therefore, it is necessary to ensure that the fall does not exceed the minimum necessary for normal use. Elastic creep should therefore be kept to a minimum. In a preferred embodiment of the pants by the method of the present invention, after 30 minutes of stretching, the final length of the elastomeric material is not greater than 1.2 times the original length.

The elasticized panels 30 may also exhibit different extensibility along the longitudinal axis when stretched in the transverse direction. The term "differential stretchability as used herein" refers to a material exhibiting a non-uniform degree of elastic stretchability as measured in the stretch direction at various points along an axis oriented substantially perpendicular to the stretch direction. This may, for example, be a variation in the modulus of elasticity or maximum stretch, or both of the material (s) / elastomeric. The differential extensibility is preferably located in the flexed flaps 30 such that the lateral stretch varies longitudinally in at least a portion of the elastified flap measured from the end edge 64 of disposable training pants 20 to the edge 106 of the leg opening of the batt. It is believed that the differential extensibility along the longitudinal axis when stretched laterally allows the elasticized flaps to stretch differently and conform to the waist of the wearer when worn, ensuring a snug fit around the wearer's hips, ensuring a snug fit around the wearer's hips and causing a tight fit around the wearer's hips. the result is a permanent fit of the shorts and minimizes leaks around the waist and legs. This solution allows for greater "expansion around the hips, adapting to the changes in the user's body size while the user moves and changes position (standing, sitting, lying). In an alternate example, the limited degree of lateral stretch in the portion of the elasticated flap adjacent to the end edge 64 of the disposable pants 20 requires that most of the total stretch be provided by the elasticized waistband 34 resulting in a more localized stretch of the elasticized waistband 34 and improved abdominal fit.

Different extensibility can be achieved in many different ways. The flexible sheets 30 can be a combination of different elastomeric materials, different compositions of elastomeric materials, or the tensile properties of an elastomeric material or other material or materials making the flexible side panel non-uniform. For example, different extensibility of individual adjoining parts of the flexed batt may be achieved by using elastomeric materials exhibiting different tensile and contraction forces, modulus or other characteristic properties such that greater or less (variable) lateral extensibility is obtained in one part of the flexible panel adjacent to another part. lobe. The elastomeric materials can also vary in length, size and shape to result in different extensibility. Other methods of varying the properties of the flexible sheet materials are known and may also be used.

A particularly preferred method and apparatus for imparting a varying degree of stretchability to a "zero-tension stretched laminate" is to pass a "zero-tension stretched laminate through at least one set of intermeshing grooved rollers, wherein at least one of the grooved rollers has grooves of non-uniform profile along the contact point or points. with "zero-tension laminate web." As a result, portions of the laminate web extending between the set of rollers are non-uniformly stretched, resulting in a "zero-tension stretch laminate that is non-uniformly elasticized in a direction substantially perpendicular to the non-uniformly profiled grooves.

In the preferred embodiment of the base portion shown in Fig. 2, the longitudinal side surface 88 is that portion of the base portion 14 which extends laterally outward from panel 72 to longitudinal edge 62. Longitudinal side surface 88 typically extends to the end edge 64 of the root portion 14. to a portion of longitudinal edge 62 of body 14 that defines the leg opening (this portion of longitudinal edge 62 is indicated as leg opening edge 106). While longitudinal side surface 88 may include a separate piece attached to flap 72 of body 14, the longitudinal side region is preferably an extension of other components of body 14 such as inner layer 46, outer layer 48, cover layer 24, backsheet 26 or any combination thereof. items. In a preferred embodiment, each longitudinal side surface 88 is formed of portions of inner layer 46 and outer layer 48 that extend beyond panel 72.

As shown in Fig. 1, rimless seams 10 are formed by joining together the longitudinal side surfaces 88 of the front portion 56 to the longitudinal side surfaces 88 of the rear portion 58. In a preferred embodiment of the method of the present invention, disposable pants are made by folding the body portion 57 at the crotch so that that the longitudinal side surfaces of the front portion 56 are closely overlapping the longitudinal side surfaces 88 of the rear portion 58 to form, as shown in Fig. 5, two areas of 40 stitches.

Figure 5A shows a preferred embodiment of the seam region 40 including longitudinal side surfaces 88 of the front portion 56 and longitudinal side surfaces 88 of the rear portion 58. Preferably, the material layers forming the seam regions have similar melting points. More preferably, each layer of the seam area is made of the same material. In a preferred embodiment, each layer of the seam area 40 comprises 100% polypropylene fibers.

170 375

The tearless seam 10 is formed by applying sufficient energy to the seam region 40 to sever a portion of the seam region 40 while fusing the narrow marginal strip adjacent the cut. The molten marginal stripe is a relatively small area and forms ν Ιλο-ζΙλ rvrr \\ u \ j¹ prm ir

7l / -t * A7-7r y Z_V_ w / y seam hito ,. ^herej 'jz_v wj wLwi y utul “Λ oa disposable shorts zu at approximately 1.6mm or less. Preferably, the tear-free seam extends beyond the garment by about 0.8 mm or less. In a preferred embodiment of the method, the tear-free seam is in fact the joint between the front portion 56 and the rear portion 58 of the base portion 14. The term "joining" as used herein refers to the act of joining, or the result thereof, end-to-end of two pieces of material sheet to form a continuous surface such that the thickness of the bond is not greater than or much greater than the thickness of the material sheet.

While there are compelling reasons why any energy should be considered mechanical energy, there are forms of energy that can be considered "non-fluff" energy, such as thermal energy, electricity and chemical energy. However, the term "mechanical energy as used herein refers to mechanical energy (e.g. ultrasonic bonding energy or autogenous pressure bonding) as well as thermal energy (e.g. energy used for hot melting). Preferably, ultrasonic energy is used to simultaneously cut and join the seam area 40 to form the seam 10 by the method of the present invention.

Preferably, mechanical energy is applied to the seam area 40 using an ultrasonic device. This generally comprises an ultrasonic transducer which receives electricity at high frequency from an electrical energy source via an electrical conductor. The transducer contains a piezoelectric transformer material to generate, by the high frequency power applied, mechanical vibrations to a pin that vibrates back and forth against the anvil base surface.

Figure 6 is a schematic top side view of a preferred ultrasonic device generally shown at 600. An ultrasonic pin 650 having an operating end 652 is coupled to an ultrasonic transducer 654 receiving high frequency electrical energy from an electrical energy source (not shown). The operative end 652 of the ultrasonic pin 650 faces an anvil 654 mounted on an axis-pivoting pulley 656. The ultrasonic pin 650 operates at an ultrasonic frequency, preferably in the range from about 20 kHz to about 40 kHz, but any other frequency within the normal operating range between 16 and 100 kHz is also suitable.

Figure 6A shows a cross-sectional view of the welding device 600 shown in Fig. 6. It is shown how the seam area 40 of the bent body 614 passes between the anvil 654 and the working end 652 as the pin 650 vibrates back and forth, i.e. to and from the anvil 654. The ultrasonic energy of the welding apparatus 600 causes the polymeric material layer in the seam area 40 to soften and flow, thinning or cutting the seam area 40 in the first area 658 while melting the seam area 40 in the thin end area 660 adjacent to the first area 658 and forming a molten mass in the first area 658. peripheral area 660. While the portion 664 of the seam area 40 that has been severed from the disposable training pants 20 is selvedge, the melt in the edge region 660 of the portion 662 of the seam area 40 that is still part of the disposable training pants 20 forms the tearless seam 10 of the disposable pants. training sessions 20.

The anvil 654 of the preferred welding apparatus 600 shown in Fig. 6A is an anvil having a bevelled edge. The anvil 654 has a contact edge 670. The width of contact edge 670 indicated by the letter W is preferably 0.76 mm. The anvil 654 also has chamfered edges 680 that form an angle with contact edge 670. The angle of the chamfered edges is indicated by the letter A and is preferably about 15 °. The width of the anvil 654 is marked with the letter W and is preferably about 2.54 mm. The height of the anvil 654 is indicated by the letter H and is preferably about 2.54 mm.

It is believed that the ultrasonic pin 650, due to the rapid low amplitude vibration, causes localized frictional energy losses, the heat of which causes softening and melting of the polymeric fibers of the seam region 40. This welding or fusing is very fast and takes place in a strictly limited zone, leaving the surrounding material essentially intact.

Examples of methods and devices for treating materials with ultrasound energy are described in US Pat. US No. 3,657,033 entitled "Methods and Devices for Continuously Cutting and Joining Sheet Thermoplastic Materials, No. 4,400,227, No. 4,430,148, No. 4,560,427 entitled" Methods and Devices for Cutting and Joining; No. 4 693 771 entitled 'Woven textile material having ultrasonically cut and welded edges and a device and method for their manufacture. In U.S. Patent No. US No. 3,457,132 entitled "Device for Cutting and Gluing, in a single opeion of webs of glued packaging material, a method and apparatus are described for cutting and gluing webs of heat-sealable material using thermal energy.

The present inventors have found that it is preferable for the polymeric material layers of the seam region 40 to have the same melting points when making the small tearless seams by the process of the invention. More preferably, the seam region 40 is made of the same polymeric material. In a preferred embodiment, each layer of seam area 40 is a non-woven fabric containing 100% polypropylene fibers.

Seams having a low tensile strength, i.e., weak seams, may be used in a disposable garment exhibiting a high degree of lateral stretch, as is the case with the disposable garment described herein. However, a stronger seam can be made by increasing the amount of polymeric material in the longitudinal side surfaces 88. The amount of polymeric material in the longitudinal side surfaces 88 can be increased by using a flexible material with a higher basis weight. If the material of the longitudinal side surfaces 88 is of a low basis weight, the amount of polymeric material in the longitudinal side surfaces 88 can be increased by introducing additional layers of material into the longitudinal side surfaces 88 such that the seam region 40 layer will contain a sufficient amount of material to form a suitable seam. Embodiments of pants that include additional layers of material in the longitudinal side surfaces 88 and therefore contain additional material in the seam region 40 are shown in the fragmentary sectional views of Figures 7 and 7A. Fig. 7 shows the inner layer 46 folded over the outer layer 48 of the longitudinal side surface 88 to form three layers of material in the longitudinal side surface 88. 7A shows an outer layer 48 folded over an inner layer 46 to form three layers of material in the longitudinal side surface 88.

Figure 11 shows another embodiment of a pant according to the method of the present invention and wherein the main part 14 comprises an outer layer 481 which has been folded to cover the elastic members 90 and the longitudinal side surfaces 88 formed. An absorbent pad 22 is attached to the outer layer 48 and includes a cover layer 24, backsheet 26 and absorbent core 28.

The disposable pants 20 includes an absorbent pad 22. The absorbent pad 22 of the disposable pants 20 is a pad, that is, an element manufactured separately from the base and slid into it. Absorbent pad 22 is any absorbent that is typically compressible, conformable, non-irritating to the wearer's skin, and capable of absorbing and retaining fluids such as urine and other body secretions.

As shown in Fig. 2, the absorbent pad 22 of the disposable pants 20 preferably comprises at least an absorbent core 28 and an outer cover layer including a cover layer 24 and a backsheet 26. The absorbent pad 22 is preferably disposed adjacent to the inner layer 46 and is preferably attached thereto by by well-known means (not shown). Suitable securing means are described below in view of connecting the backsheet 26 to the absorbent core 28.

Absorbent core 28 can be any absorbent that is typically compressible, conformable, non-irritating to the wearer's skin, and capable of absorbing and retaining.

170 Urine and other body secretions. As shown in Figs. 2 and 4, the absorbent core 28 has a pants-side surface 100, a body-side surface 101, side edges 82, and end edges 83.

Rdz ihcnrbiry / jny / can hvć wvtw / nrznnv in a wide range of sizes /

XX ^ X_ ~ ,, JV ~ XX- ~ * Xj "C, X ^ X_XXXXXX ~~ XXXW ^ X ~ X shapes (e.g. rectangular, hourglass, T-shaped, asymmetrical etc.) and with a wide variety of liquid-absorbing materials typically used in disposable diapers and other absorbent articles such as wood pulp, generally used as a filling. Examples of other suitable absorbent materials include waste cellulose wadding, heat blown polymers including creped cellulose wadding, cross-linked cellulose fibers, fabrics including woven cloths, absorbent foams, absorbent sponges, super absorbent polymers, gelling absorbent materials, or any equivalent material or combination of materials. The configuration and structure of the absorbent core may vary (for example, the absorbent core may contain variable zones of thickness, a hydrophilic gradient, a superabsorbent gradient, or absorbent zones of lower average density and lower basis weight, or may contain one or more layers or structures). The total absorption capacity of the absorbent core 28, however, should correspond to the design load and intended use of disposable pants 20. Further, the size and absorption capacity of the absorbent core 28 can be varied to suit the user, from children to adults.

A preferred embodiment of the absorbent body 22 comprises an absorbent core 28 in the shape of a symmetrical modified hourglass glass. Although the preferred absorbent core 22 comprises an absorbent core 28 in the shape of a symmetrical modified hourglass glass, it should be understood that the size, shape, configuration, and overall absorbency of the absorbent core 28 may be varied to suit a user from children to adults. Therefore, the size, shape, configuration, and overall absorption capacity of the absorbent core can be varied (for example, the absorbent agent may have variable zones of thickness, a hydrophilic gradient, may not contain or contain gelling absorbent materials). An exemplary absorbent structure for use as absorbent core 28 that has gained wide acceptance and commercial success is described in US Pat. US No. 4,610,678 entitled "High Density Absorbent Structures, No. 4,673,402 entitled" Dual Layer Core Absorbent Articles and 4,888,231 entitled "Absorbent Core Including Abrasive Layer, describe absorbent structures useful for pants made by the process of the present invention. . The absorbent core 28 is preferably cotton wool and particles of gelling absorbent material about 13 centimeters wide (lateral size), about 37 centimeters long (longitudinal size) and about 8 centimeters across the narrowest point of the crotch 57. Preferably part of the absorbent core. which is typically located at the front portion 56 and the crotch portion 57 has a higher basis weight than the portion normally located at the rear portion 58. More preferably, the portion of the absorbent core that is typically positioned on the front portion 56 and the crotch portion 57 has a grammage three times greater than that of the portion that is typically positioned on the back portion 58. In a preferred example, the portion of absorbent core 28 about 25.4 long The centimeter is typically located on the front 56 and crotch 57 and has a basis weight of about 0.107 grams per square centimeter. A portion of the absorbent core 28 that is about 11.4 centimeters long is typically located on the back portion 58 and has a basis weight of about 0.036 grams per square centimeter.

The backsheet 26 is positioned tangentially to the surface of the absorbent core 28 on the garment side 100 and is preferably attached thereto by well-known means (not shown). For example, the backsheet 26 may be attached to the absorbent core 28 by a uniform adhesive layer, a patterned adhesive layer, or an array of discrete lines, spirals, or adhesive dots. Adhesives found to be of satisfactory quality are manufactured by Century Adhesives, Inc. of Columbus, Ohio and marketed as Century 5227, and by HB Fuller Company of St. Paul, Minnesota and sold as HL-1258. The fastening means preferably comprises a web pattern of glue threads as described in the S1 patent. In US 4 579 867 entitled "Disposable Garment With Dirt Absorber. An exemplary fastening means is an open pattern of web of glue threads twisted in a spiral pattern, as illustrated by the apparatus and methods shown in US Pat. U.S. No. 3,911,173, No. 4,785,996, No. 4,842,666.

Alternatively, the fastening means may be a heat seal, pressure joint, ultrasonic welding, dynamic-mechanical joint, or any other known joint.

Backsheet 26 is impermeable to liquids (e.g. urine) and is preferably made of a thin plastic film, although other flexible liquid impermeable materials may also be used. As used herein, the term elastic refers to materials that are compliant under pressure and quickly conform to the overall shape and contours of the human body. The backsheet 26 separates the exudates absorbed and retained by the absorbent core 28 from the wicking elements that contact you with disposable pants 20, such as bedding and underwear. The backsheet 26 may comprise a woven or non-woven material, a polymeric film such as a thermoplastic polyethylene or polypropylene film, or a composite material such as a film-coated nonwoven material. Preferably, the backsheet is a foil from about 0.012 mm to about 0.051 mm thick.

The size of the backsheet 26 corresponds to the size of the absorbent core 28 and a carefully selected garment pattern. In a preferred embodiment, the backsheet 26 wraps at least the absorbent core and preferably the edges of the topsheet 24 at least in the crotch portion 57 such that the backsheet material is offset from the elasticized leg cuffs 32, so that the backsheet material does not obstruct them. Alternatively, the topsheet 24 may wrap around the absorbent core and extend under the edges of backsheet 26 at least in the crotch portion 57, or the topsheet 24 and backsheet 26 may be "cut sideways in the crotch portion 57 so that the backsheet material will not obstruct the crotch portion. elasticized cuffs of 32 legs.

The topsheet 24 is disposed tangentially to the body side surface 101 of the absorbent core 28 and is preferably attached thereto and the absorbent core 28 by well known means (not shown). Suitable attachment means have already been described in relation to the connection of the backsheet 26 to the absorbent core 28. In a preferred example of pants made by the method of the present invention, the topsheet 24 and the backsheet 26 are connected to each other directly at the points extending beyond the absorbent core 28 and are connected indirectly to each other by connecting them directly to the absorbent core 28 by means of securing means (not shown). ).

The topsheet 24 is compliant, soft to the touch, and non-irritating to the wearer's skin. In addition, the topsheet 24 is permeable to liquids (e.g., urine), allowing liquids to quickly penetrate into it. A suitable top layer can be made of a variety of materials such as porous foams, cross-linked foams, perforated plastic films, woven or non-woven webs of natural fibers (e.g. cellulose or cotton fibers), synthetic fibers (e.g. polyester or polypropylene fibers) or combinations of fibers natural and synthetic. Preferably, the topsheet 24 is made of a water-repellent material containing about 20% to 30% rayon to provide a feeling of moisture that signals a baby's toilet training to pass urine.

There are a number of methods that can be used to make the surface layer 24. For example, the surface layer 24 may be a nonwoven web. If the topsheet comprises a non-woven web, it may be spun, carded, wet-coated, blown, wet braided, or a combination of the above methods. Preferably, the outer layer is carded and thermally bonded according to known manufacturing methods. A suitable top layer is manufactured by Fiberweb North America and available as an 80/20 polypropylene / rayon nonwoven fabric, carded and thermally bonded.

170 375

However, in the preferred embodiment, the topsheet 24 is not part of the body 14 but is manufactured separately and inserted as part of an absorbent body.

22, the main part 14 can be manufactured without the inner layer 46 and the outer layer

... w.,.! ,, "u,", u.oo. "λ i ,,., ---- oz:" "wkiadu ausuiuLjjc ^ \ ^ e-go '2.2. it can extend beyond the height of the lower portion 2.6 at the front 56 and rear 58 of the base portion 14 so that the top layer 24 can extend over the elastic members 90 of the airfoil and form the interior surface of the base portion 14 (as shown in Fig. 10). In this example, at least a portion of the topsheet 24 is stretched to provide a "zero-tension stretch laminate that forms the resilient side panels 30. Thus, in this variant, the topsheet 24 should be elongate, preferably stretchable, but not necessarily elastomeric, such that the topsheet 24, when mechanically stretched, remains at least some degree permanently elongated, i.e. not completely returning to its original state. However, this variant is undesirable as urine may "leak beyond the central zone 68 of body Mi without being retained by the absorbent pad 22.