PANT-TYPE GARMENT AND METHOD FOR THE PRODUCTION THEREOF

Abstract

The front and back portions are joined in a first and a second side seam along opposing side edges of the front and back portions and comprising a stretch-bonded laminate web including an elastic film which is stretch-bonded between two nonwoven webs. The side seams are constituted by fusion bonds formed by laser bonding and extend along the side edges of the front and back portions of the pant-type garment. The side seams have a width in the width direction of the pant-type garment in the range of from 0.3 to 1.5 millimetres, and a thickness in the range of from 0.2 to 1.5 millimeters, the thickness of the side seams being perpendicular to the width direction and the length direction of the pant type garment.

Claims

1. A pant-type garment having a length direction and a width direction and being divided in the length direction into a front portion, a back portion and a crotch portions located between the front portions and the back portion, the front portion having a front waist edge extending in the width direction and a pair of opposing side edges extending in the longitudinal direction and the back portion having a back waist edge extending in the width direction, and a pair of opposing side edges, extending in the longitudinal direction, the front and back portions being joined in a first and a second side seam arranged in first and second side seam regions and being formed by superposed layers of the front and back portions along the opposing side edges of the front and back portions, the first and second side seam regions comprising thermoplastic web material, the side seams being constituted by fused thermoplastic material extending along the side edges of the front and back portions of the pant-type garment, wherein each of the side seams has a width in the width direction of the pant-type garment in the range of from 0.3 to 1.5 millimetres, and a thickness in the range of from 0.2 to 1.5 millimeters, the thickness of the side seam being perpendicular to the width direction and the length direction of the pant type garment and in that the material of the front and back portions comprises an elastic laminated comprising an elastic film which is stretch-bonded between two outer nonwoven webs, the side seams being fully or partly formed in the elastic laminate.

2. A pant-type garment according to claim 1, wherein the elastic film is intermittently bonded between the outer nonwoven webs with a bonding pattern comprising discrete bonding elements.

3. A pant-type garment according to claim 2, wherein a bonded area of the elastic laminate is from 3% to 20%.

4. A pant-type garment according to claim 1, wherein the elastic laminate has a material thickness and wherein a ratio t.sub.s/t.sub.m between the thickness of the side seam and the material thickness is in the range of from 1.0 to 1.3, as measured by the method as disclosed herein.

5. A pant-type garment according to claim 1, wherein the elastic film is severed along the side seams and a non-elastic area extends along 60% to 100% of each of the side seams, the non-elastic area having a width on each side of the side seam of from 0.7 millimetres to 20 millimetres.

6. A pant-type garment according to claim 1, wherein the side seams are located on a garment facing surface of the pant-type garment.

7. A pant-type garment according to claim 1, wherein a ratio of the width of the side seams to the thickness of the side seams is in the range of from 0.7 to 1.5.

8. A pant-type garment according to claim 1, wherein each side seams has a generally rectangular cross-sectional area along 60% to 100% of the length of the side seams in the longitudinal direction of the pant-type garment.

9. A pant-type garment according to claim 1, wherein the elastic laminate constitutes a cover material, the cover material forming all or part of an outer cover of the pant-type garment.

10. A pant-type garment according to claim 9, wherein the cover material is a single, unitary cover web comprising a front portion, a back portion and a crotch portion between the front portion and the back portion.

11. A pant-type garment according to claim 9, wherein the cover material comprises a front panel web and a back panel web the front panel web and the back panel web being separate webs and being joined by a crotch material.

12. A pant-type garment according to claim 1, wherein at least one nonwoven web which is involved in forming the sides seams of the pant-type garment comprises at least one spunbond layer and optionally at least one meltblown layer.

13. A pant-type garment according to claim 1, wherein the thermoplastic material in the areas of the side seams comprises or consists of polypropylene and/or polyethylene.

14. A pant-type garment according to claim 1, wherein the pant-type garment comprises a waist elastic feature extending along all or part of one or both of the front waist edge and the back waist edge.

15. A pant-type garment according to claim 1, wherein the elastic film is severed along the side seams and a non-elastic area extends along 80% to 100% of each of the side seams, the non-elastic area having a width on each side of the side seam of from 0.9 millimetres to 5 millimetres.

16. A pant-type garment according to claim 1, wherein a ratio of the width of the side seams to the thickness of the side seams is in the range of from 0.9 to 1.2.

17. A pant-type garment according to claim 1, wherein the elastic laminate has a material thickness and wherein a ratio t.sub.s/t.sub.m between the thickness of the side seam and the material thickness is in the range of from 1.1 to 1.3, as measured by the method as disclosed herein.

18. A pant-type garment according to claim 1, wherein the elastic laminate has a material thickness and wherein a ratio t.sub.s/t.sub.m between the thickness of the side seam and the material thickness is in the range of from 1.1 to 1.2, as measured by the method as disclosed herein.

19. A pant-type garment according to claim 2, wherein a bonded area of the elastic laminate is from 3% to 15%.

20. A pant-type garment according to claim 2, wherein a bonded area of the elastic laminate is from 4% to 10%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The present invention will be further explained hereinafter by means of non-limiting examples and with reference to the appended drawings wherein:

[0066] FIG. 1 shows a front view of an example pant-type garment with a two-part outer cover;

[0067] FIG. 2 shows a front view of an example pant-type garment with a unitary cover;

[0068] FIG. 3 shows a detail view of a side seam in a pant-type garment as disclosed herein;

[0069] FIG. 4 shows a cross-section taken along the line IV-IV through the side seam in FIG. 3;

[0070] FIG. 5 shows a precursor web for a pant-type garment with a two-part outer cover;

[0071] FIG. 6 shows a precursor web for a pant-type garment with a unitary cover;

[0072] FIG. 7 shows a side view of an apparatus for simultaneously forming side seams and severing individual pant-type garments from a precursor web of interconnected pant-type garments;

[0073] FIG. 8 FIGS. 8a, 8b and 8c show a precursor web of pant-type garments during processing in an apparatus such as shown in FIG. 7;

[0074] FIG. 9 shows the path of a laser beam during processing of a precursor web of pant-type garments when simultaneously forming side seams and severing individual pant-type garments from the precursor web of interconnected pant-type garments;

[0075] FIG. 10 shows a cross section taken along the line X-X in FIG. 8c;

[0076] FIG. 11 shows schematically where samples may be cut out from a pant-type garment;

[0077] FIG. 12 shows a sample fastened between two claps in a tensile tester; and

[0078] FIG. 13 shows a stretched-out sample for measuring of thickness.

DETAILED DESCRIPTION

[0079] It is to be understood that the drawings are schematic and that individual components, such as layers of material are not necessarily drawn to scale. The disposable pant-type absorbent garments shown in the figures are provided as examples only and should not be considered limiting to the invention as disclosed herein. As set out herein, the invention is applicable also to non-absorbent garments and reusable pant-type garments or garments which can be laundered and reused a limited number of times. Reusable garments which may withstand laundering may be non-absorbent pant-type garments e.g. pant-type garments which are adapted for use together with an absorbent insert.

[0080] Furthermore, the construction of the pant-type garments may be different from those shown in connection with the figures. As set out herein, an alternative construction of a unitary chassis may comprise a single continuous outer cover sheet, and/or a continuous inner liner and elastic panel webs joined to one or both of the front and back part of the chassis to form an elastic front or back panel, respectively.

[0081] The pant-type garments shown in the figures are simplified garments, and it should be understood that they may be enhanced with elastic elements arranged at the leg openings on one or more of the front panel, the back panel and in the crotch portion. Further elastification may be provided e.g. in the form of barrier cuffs. It is also to be understood that the waist elastic disclosed in connection with FIGS. 1 and 2 is optional or that it may be substituted by any other type of elastic waist feature as known in the art. The pant-type garments 1 which are shown in FIGS. 1 and 2 are illustrated in an extended state similar to how they appear when extended to fit the lower trunk of a user.

[0082] The pant-type garment 1 shown in FIG. 1 has a longitudinal direction L and a width direction W and comprises a two-piece outer cover 9′ forming a front panel 3 and a back panel 4 of the pant-type garment 1, the front and back panels 3, 4 being arranged at a front portion 15 and a back portion 16 of the pant-type garment 1. A core insert 2 is located mainly in a crotch portion 10 of the pant-type garment 1 between the front portion and the back portion 16 as seen in the longitudinal direction (L). The core insert 2 bridges a gap between the front and back portions 15, 16 and extends with end portions 11 in over the front and back portions 15, 16 and is connected at the end portions 11 to an interior side of the front and back portions 15, 16. The core insert 2 is a separately produced component which comprises an absorbent core 5 for absorbing body fluid. The front portion 15 has a front waist edge 21′ and a pair of side edges 22a, 22b, and the back portion 16 has a back waist edge 21″ and a pair of side edges 24a, 24b. The side edges 22a, 22b, 24a, 24b of the front and back portions 15, 16 are joined in side seams 6a, 6b, thereby forming the pant-type garment 1 having a waist opening 7 and two leg openings 8.

[0083] The side seams 6a, 6b are arranged in side seam regions 12 of the pant-type garment 1. The side seam regions 12 are the parts of the pant-type garment 1 which during use are placed over the hips of a user. Each side seam regions 12 extends between the waist opening 7 to a corresponding one of the leg openings 8 of the pant-type garment 1. As set out herein, the pant-type garment 1 comprises or consists of superposed webs within the side seam regions 12. As seen in FIGS. 3 and 4, the side seams 6a, 6b are formed as fused strips in web material which includes thermoplastic polymer material and which is arranged along the side edges 22a, 22b, 24a, 24b of the front and back portions 15, 16 of the the pant-type garment 1.

[0084] The pant-type garment 1 which is schematically shown in FIG. 1 is illustrated in an extended state and is fully assembled and ready-to-use. The pant-type garment 1 shown in FIG. 1 is an absorbent garment and may be a pant diaper, a sanitary pant or an incontinence pant and may be adapted for use of an adult female or male user.

[0085] The material in the back panel 4 may be the same or different from the material in the front panel 3. At least one of the front panel 3 and the back panel 4, and preferably both the front panel 3 and the back panel 4 are formed from a stretch bonded laminate web comprising a layer of elastic material, such as an elastic film layer which is sandwiched between two outer nonwoven layers. The bonding of the layers of the laminate web may be effected by means of an intermittent pattern of discrete bond elements as set out herein. Bonding may be made by any suitable method, with ultrasonic bonding being generally preferred.

[0086] FIG. 2 shows a second example of a pant-type garment 1, such as a garment for an adult female or male user. The pant-type garment 1 is schematically illustrated in an assembled and ready-to-use state. The difference between the pant-type garments in FIGS. 1 and 2 is that the pant-type garment 1 in FIG. 2 has a unitary outer cover 9″, i.e. the front and back portions 15, 16 comprises a web material which is continuous at least in the longitudinal direction L of the pant-type garment 1 and which includes a crotch portion 10 interconnecting the front and back portions 15, 16, the crotch portion 10 being integrally formed with the front and back portions 15, 16. In the pant-type garment 1 in FIG. 2, there is no clear delimitation between the front portion 15, the crotch portion 10 and the back portion 16, while in FIG. 1 the crotch portion 10 is defined between the front and back panels 3,4.

[0087] The unitary outer cover 9″ including the front portion 15, the back portion 16 and the interconnecting crotch portion 10 may preferably be fully or partly formed from a stretch bonded laminate web as disclosed herein and comprising a layer of elastic material, such as an elastic film layer which is sandwiched between two outer nonwoven layers.

[0088] At least one and preferably both of the front portion 15 and the back portion 16 in the examples of FIGS. 1 and 2 includes or consists of an elastic laminate web as disclosed herein such as a laminate of an elastic film sandwiched between two fibrous outer layers. The elastic laminate need not be identical all over its area, but may comprise different layers in different areas. In FIG. 1, the front portion 15 is coextensive with the front panel 3 and extends in the longitudinal direction L of the pant-type garment 1 from an upper part of a leg edge 23 to a waist edge 21 and in the width direction W from one side seam 6a to the other side seam 6b. The back portion 16 is coextensive with the back panel 4 and extends in the longitudinal direction L of the pant-type garment 1 from an upper part of a leg edge 23 to the waist edge 21 and in the width direction W from one side seam 6a to the other side seam 6b. As shown in FIG. 1, the front portion 15 and the back portion 16 of the pant-type garment as disclosed herein may be provided with a waist elastic feature 25 which may e.g. be in the form of supplementary elastic elements attached along the waist edge 21 of the pant-type garment 1, a separately produced elastic waist-band attached along the waist edge 21 of the pant-type garment 1, or may be of any other suitable kind as set out herein.

[0089] The shape of the front and back portions 15, 16 may be varied to fit a particular category of user. For example, one or both of the front portion and the back portion 15, 16 may have a substantially rectangular shape. Moreover, a leg edge region of the front and/or back portions 15, 16 may have a curved shape adapted to provide better conformance to a leg. As is illustrated in FIGS. 1 and 2, the back panel portion 16 may have a greater extension in the longitudinal direction L of the pant-type garment than the front portion 15 in order to provide better coverage of the buttocks of a user. However, the front and back portions 15, 16 may have equal extensions in the longitudinal direction L. Although generally less preferred, the front portion 15 may have a greater extension in the longitudinal direction L of the pant-type garment 1 than the back portion 16.

[0090] With reference to FIGS. 3 and 4 there is shown a detail view of a side seam 6 connecting a front portion 15 and a back portion 16 of a pant-type article 1, e.g. a pant-type garment 1 as shown in FIGS. 1 and 2. The side seam 6 is formed by of fused thermoplastic material and has a length l.sub.s in the longitudinal direction L of the pant-type garment 1 from a waist edge 21 to a leg edge 23 of the pant-type garment 1 and a width w.sub.s in the width direction W of the pant-type garment 1. The side seam 6 extends in the length direction L across a waist elastic feature 25 which is arranged along the waist edge 21. As set out herein, the waist elastic feature 25 may be of any kind as known in the art. In the example shown in FIG. 3, the front and back portions 15, 16 are constituted by a three-layer elastic laminate 17 having an elastic film 27 bonded between an inner nonwoven web 26 and an outer nonwoven web 28. The waist elastic feature 25 is a waistband which has been created by attaching multiple spaced-apart elastic strings 44 on the outer nonwoven web and covering the elastic strings with a folded-over part 45 of the inner nonwoven web layer of the three-layer elastic laminate of the front and back portions 15, 16. Regardless of the type of waist elastic feature 25, a waist elastic feature extending into the side seam 6 means that material such as elastic elements and any covering or support layer would be present in the side seam. As in the FIG. 3 example, the waist feature materials are often present in addition to the materials forming the front and back portions 15, 16. It has been found that the presence in the side seam of such additional material does not significantly affect the side seam strength either positively or negatively.

[0091] In the example shown in FIGS. 3 and 4 the front portion 15 and the back portion 16 are both made from elastic web material forming an outer cover at least within the areas of a front panel 3 and a back panel 4 or within elastic side flaps. The elastic web material is a three-layer laminate 17 comprising an inner elastic film 27 which has been stretchbonded between an outer and an inner nonwoven layer 28. The nonwoven layers 26, 28 are non-elastic or less elastic than the elastic film 27 and the elastic film layer 27 is bonded between the nonwoven layers 26, 28 while being stretched by at least 50% at least in a direction corresponding to the width direction W of the pant-type garment 1.

[0092] Bonding of the stretchbonded three-layer laminate is made by means of intermittently applied discrete bond elements as disclosed herein.

[0093] When the elastic laminate web is allowed to relax after bonding, the elastic film retracts, causing the non-elastic or less elastic nonwoven webs to gather and form wrinkles and rugosities on the outer surfaces of the elastic laminate web. The textile appearance of the outer surface of the elastic laminate web may be enhanced by using a bonding pattern which promotes formation of a regular pattern of rugosities. A particularly suitable bonding pattern may be a pattern of off-set point bonds which causes the gathered nonwoven webs to pucker in a controlled and regular way in the non-bonded portions between the point bonds. Such controlled puckering of the nonwoven webs may be made to resemble a woven pattern and provides the elastic laminate web with high-loft, soft and airy cushioning outer layers having a functional thickness which is considerably greater than the thickness of the non-gathered nonwoven webs. The point bonds may be created e.g. by thermobonding or by ultrasonic bonding, with ultrasonic bonding being preferred, as disclosed herein. It may be particularly preferred that the elastic film layer is a non-thermoplastic film and the nonwoven layers are thermoplastic layers or at least predominantly thermoplastic layers and that bonding of the elastic film layer between the nonwoven web layers is carried out by simultaneously perforating the elastic film layer and create fusion bonds between the nonwoven web layers at the perforations in the elastic film layer. An elastic laminate which has been made in this way has excellent breathability and is highly suitable for use as an outer cover in a pant-type garment as disclosed herein.

[0094] With reference to FIG. 4, it can be seen that the side seam 6 has the form of having a generally rectangular or box-shaped cross-sectional area a.sub.s, as set out herein. The three-layer elastic laminate 17 in the front and back panels 3, 4 is shown in a gathered state as it would appear when being taken out of a package. The three-layer elastic laminate 17 will also be at least somewhat gathered during wearing of the pant-type garment. In this state, the inner and outer nonwoven layers 26, 28 of the three-layer elastic laminate 17 assume a puckered configuration, with an apparent thickness which is considerably greater than the thickness of the box-shaped side seam 6. The side seam 6 is arranged on the outer, garment-facing surface of the three-layer elastic laminate 17 of the front and back portions 15, 16 and has an outer surface 18 located a distance d inward of the outer surface 19 of the three-layer elastic laminate 17 of the front and back portions 15, 16. In this manner the relatively stiff consolidated material in the fused elongated side seam 6 is effectively shielded by the soft and lofty material in the front and back portions 15, 16. Furthermore, the rugosities in the three-layer elastic laminate also serve to conceal the side seam, making the side seam almost invisible to the naked eye when the garment is being worn.

[0095] FIG. 5 shows a precursor web 35 for forming pant-type garments 1 of the kind disclosed herein and having a two-piece outer cover 9′, e.g. as illustrated in FIG. 1. The precursor web 35 may be formed by manufacturing two parallel continuous elastic laminate webs 31′, 31″, such as stretchbonded laminated elastic webs, and intermittently connecting the continuous elastic laminate webs 31′, 31″ with a crotch material, such as a core insert 2 while moving the precursor web 35 in a machine direction MD.

[0096] Depending on the desired shape of the leg openings of the pant-type garment 1, the web material may be cut and shaped to provide a more underwear-like shape and better fit of the pant-type garment 1.

[0097] A separately fabricated core insert 2 is placed in the gap between the elastic laminate webs 31′, 31″ while the webs 31′, 31″ are held in a tensioned state in the machine direction MD, such that the core insert 2 partly overlaps with both of the elastic laminate webs 31′, 31″. The absorbent insert 2 may be secured to the elastic laminate webs 31′, 31″ by any suitable method or combination of methods, such as by welding, thermobonding, by means of adhesive, etc.

[0098] The precursor web 35 is a continuous web having leg openings 8 arranged therein and consisting of interconnected precursor pant-type garments 36. As shown in FIG. 5, the precursor web 35 is folded along a fold line F, extending in the machine direction MD, centrally along the precursor web 35.

[0099] After the precursor web 35 has been folded, side seams 6a, 6b are formed in side seam areas 112 of the precursor web 35 and individual pant-type garments 1 are separated from the precursor web 35 by severing the precursor web at the same time as the side seams 6a, 6b are formed.

[0100] The precursor web 35 which is illustrated in FIG. 6, is a continuous web of precursor pant-type garments 36 of the kind as disclosed herein and having a unitary outer cover, such as the pant-type garment 1, shown in FIG. 2. The precursor web 35 in FIG. 6 is formed by moving an elastic laminate web 31 in a machine direction MD; intermittently applying core inserts 2 to the moving elastic laminate web 31 and cutting out leg openings 8 between the core inserts 2. The precursor web 35 is subsequently folded along a fold line F extending in the machine direction, MD.

[0101] A precursor web of pant-type absorbent garments having a unitary cover may alternatively be produced by applying absorbent cores between moving continuous inner and outer cover webs, at least one of the cover webs having a width in the cross machine direction CD corresponding to a full length of the unitary cover. Furthermore, the precursor web may comprise components which are not shown in the figures, such as a barrier layer, an acquisition layer, leg elastic elements, etc., as known in the art.

[0102] After the precursor web 35 has been folded, side seams are formed in the folded precursor web 35 and individual pant-type garments 1 are separated from the precursor web 35 by severing the precursor web at the same time as forming side seams 6a, 6b between the precursor pant-type garments 36.

[0103] It is to be understood that the elastic material in the elastic laminate web 31 needs not be continuous in the cross machine direction, CD. By way of example, the elastic material may be applied only in one or both of the areas of the elastic laminate web 31 corresponding to the front and back panels 3, 4 in the pant-type garment 1.

[0104] FIG. 7 shows an apparatus 100 for simultaneously forming side seams and severing individual pant-type garments of the kind disclosed herein from a precursor web 35 of interconnected precursor pant-type garments 36. The apparatus comprises a support roll having an outer peripheral support surface 41 for supporting the precursor web 35 during formation of side seams and severing individual pant-type garments 1 from the precursor web 35. The support roll 40 has a rotating direction R coinciding with a machine direction MD of the apparatus 100. The apparatus further has a cross machine direction CD perpendicular to the machine direction MD and the rotating direction R of the support roll 40.

[0105] The apparatus 1 is provided with a lay-down arrangement 70. In FIG. 7, the lay-down arrangement is shown as a deflection roll which feeds the precursor web 35 in the machine direction MD onto the support surface 41 at a lay-down position 80 on the outer periphery of the support roll 40.

[0106] The precursor web 35 which may be separated into individual pant-type garments 1 may be a precursor web such as shown in FIGS. 3 and 4. The precursor web 35 is laid-down on the support surface 41 of the support roll 40 as a continuous web of interconnected pant-type garments 36. At the end of the laser welding and cutting operation as disclosed herein, individual pant-type garments 1 have been severed from the continuous precursor web 35 and can be removed and transported to folding and packaging equipment downstream of the welding and cutting apparatus 100.

[0107] The apparatus 100 is further provided with one or more pressing arrangements 110. The apparatus 1 which is shown in FIG. 7 has six pressing arrangements 110 equidistantly spaced along the outer periphery of the support roll 40. The number of pressing arrangements 110 is not critical to the apparatus or the method as disclosed herein, and it is to be understood that any useful number of pressing arrangements may be used, as set out herein. The spacing between the pressing arrangements 110 may preferably be selected to correspond to a pitch-length of the pant-type garments 1 in the machine direction MD.

[0108] The pressing arrangement 110 is provided with pressing means, such as the press clamps 170 shown schematically in FIGS. 8a, 8b,8c and which are arranged for pressing the precursor web 35 against the support surface 41 within pressing areas 111 arranged on opposite sides of a side seam area 112 of a leading and a trailing individual pant-type garment 1a, 3b, as seen in the machine direction MD. The pressing areas 11 are located adjacent and along the side seam area 112. A laser beam passage 150 is arranged in the press clamp 170 between the pressing areas 111. The laser beam passage 150 is shown in FIGS. 3 and 4 as a narrow opening or slit in the press clamp 170. As set out herein, the laser beam passage 150 may alternatively be provided e.g. as a gap between spaced-apart pressing bars or as an opening in a pressing belt. The laser beam passage 150 has a length in the cross machine direction CD which is equal to or greater than a length of a side seam 6a, 6b which is to be formed in the precursor web 35. The press clamp 170 is applied to the precursor web with the laser beam passage 150 in registry with and overlying the side seam area 112 on the support surface 41 on the outer periphery of the support roll 40. Thereby, the side seam area 112 is completely accommodated within the laser beam passage 150.

[0109] A laser unit 200 is arranged at a welding section 210 of the outer periphery of the support roll 40. The laser unit 200 is configured to direct a laser beam 220 through and along the laser beam passage 150 as shown in FIGS. 8a, 8b, 8c. The laser unit 200 is configured to generate the laser beam 220 and to move the focus point f of the laser beam 220 along the laser beam passage 150 from one end of the laser beam passage 150 to the other end of the laser beam passage 150 in the cross machine direction CD. As the support roll is continuously rotating, the focus point f must simultaneously be moved in the machine direction MD in synchrony with the rotation of the support roll 40, as is illustrated in FIG. 9. The focus point f should be kept at a constant distance from the support surface during movement of the laser beam 200 along the laser beam passage 150. As the laser unit 200 is stationary while the support roll 40 rotates in the machine direction MD and the laser beam 220 is moved across the support surface 41 in the cross machine direction CD, the distance between the laser unit 200 and the support surface 41 varies during the welding and cutting operation carried out in the welding section 210. The laser unit 200 is therefore also configured such that the position of the focus point f of the laser beam 220 is adapted to the varying distance between the laser unit 200 and the support surface 41.

[0110] As used herein, a laser unit which is configured to adapt the position of the focus point f of the laser beam comprises means e.g. a data processing unit which based on relevant in-data, such as rotational speed of the support roll, radius of the support roll, length and shape of the laser beam passage, etc. can out-put a control signal to change settings of the laser generating equipment in the laser unit.

[0111] FIGS. 8a, 8b and 8c show a part of the support roll 40 and the support surface 41 with a precursor web 35 pressed against the support surface 41 by a press clamp 170 which is part of a pressing arrangement 110. Only the part of the support surface 41 and the precursor web 35 where side seams 6a, 6b are to be formed is shown in FIGS. 8a, 8b and 8c. The upper part of FIGS. 8a, 8b and 8c shows a waist edge 21 and a waist elastic feature 25 while the lower part of FIGS. 8a-8c show an upper part of the leg edges 23 of the pant-type garments 1 in the precursor web 35.

[0112] FIGS. 8a, 8b and 8c illustrate how side seams 6a, 6b are formed in the precursor pant-type garments 36a, 36b at the same time as individual pant-type garments 1 are severed from the precursor web 35. By applying laser energy to the precursor web 35 through the laser beam passage 150, thermoplastic material in superposed layers of the precursor web is locally melted and fused within the side seam area 112, and at the same time, the precursor web 35 is severed to separate individual pant-type garments from the precursor web 35. The laser beam 220 is directed through and along the laser beam passage 150 from outside the support roll 40, which makes the laser unit 200 and the pressing arrangements 110 easily accessible for maintenance and replacement. Furthermore, a fume removal arrangement 80 may be provided on the outside of the support roll 40, preferably such that fumes generated by the welding and severing process can be removed directly from the welding section 210 of the support roll 40.

[0113] As set out herein the laser beam 220 is controlled to move along the laser beam passage 150 in the cross machine direction CD of the support surface 41 and in the machine direction MD in synchrony with rotation of the support roll 40, while adapting the position of the focus point f of the laser beam 220 to a varying distance between the laser unit and the support surface 41, such that the focus point f is kept at a constant distance from the support surface 41.

[0114] FIG. 9 shows how the focus point f of the laser beam 220 moves both in the cross machine direction CD and in the machine direction MD as the laser beam passage 150 in the clamping arrangement 110 moves through the welding section 210 and the side seams 6a, 6b are formed. FIG. 9 shows the focus point f moving from the left-hand side of the laser beam passage 150 to the right-hand side of the laser beam passage 150 which may be taken to correspond to the welding process being performed from a waist edge 21 to a leg edge 23 on the precursor web 35. It is to be understood that it is equally viable to form the side seams 6a, 6b in the opposite direction, i.e. from right to left in FIG. 9 corresponding to the side seams being formed from a leg edge 23 to a waist edge 21 on the precursor web 35.

[0115] When the precursor web 35 has travelled through the welding section 210 and the laser beam has acted on the precursor web 35, a cut is formed along a cut line 85 as is shown in FIG. 8b. The cut line 85 is created by the moving focus point f of the laser beam 220. The focus point f of the laser beam 220 may be located on the support surface 41 of the support roll 40, but is preferably located at a distance from the support surface 41 in order to create a slight defocus of the laser beam and a larger incidence area on the precursor web 35. A laser beam having the focus point f at a distance from the support surface 41 of from 25 to 35 millimetres has been found to provide a particularly useful combination of good side seam strength and a distinct cut between the side seams. However, the focus point f of the laser beam may be at 0 to 60 millimetres from the support surface of the support roll, such as at 20 to 40 millimetres from the support surface of the support roll, or at 25 to 30 millimetres from the support surface of the support roll.

[0116] The material in the precursor web 35 is completely melted and/or evaporated along the cut line 85. In the portions of the side seam area 112 which are located on either side of the cut line 85 thermoplastic material in the precursor web 35 is melted and/or softened such that narrow band-shaped fusion bonds are formed along the inner edges of the laser beam passage 150, creating one side seam 6a on a leading precursor pant-type garment 36a and one side seam 6b on a trailing precursor pant-type garment 36b. Fusion of the thermoplastic material in superposed layers of the precursor web 35 is promoted by the pressure applied by the pressure means such as the press clamps 170 of the pressure arrangement at the very edges of the side seam area 112. Without wishing to be bound to theory, it is also believed that the pressure applied along the edges of the side seam area 112 contributes to promote separation of the individual pant-type garments 36a, 36b along the cut line 85, as is shown in FIG. 8c. Separation of individual garments 1 is further enhanced by stretching the precursor web 35 in the machine direction MD while the precursor web 35 is held on the support roll 40.

[0117] FIG. 10 is a cross-section taken along the line X-X in FIG. 8c and shows the newly formed and separated side seams 6a, 6b of a leading and a trailing precursor pant-type garment 36a, 36b. The superposed layers of the front panel web 13 and the back panel web 14 of the precursor garments 36a, 36b are pressed down on the support surface 41 by means of the press clamps 170 (or other pressing means) exerting a pressure force P on the pressing areas 111 immediately adjacent the side seams 6a, 6b.

[0118] Immediately after the side seams 6a, 6b have been formed in the welding section 210 of the apparatus 100 shown in FIG. 7, the fused thermoplastic material is still hot and soft and needs to be cooled down and solidify to create strong functional side seams 6a, 6b.

[0119] In order for the side seams 6a, 6b to solidify, the severed precursor web 35 is transported along a cooling section 137 of the support roll 40. When moving through the cooling section 137, the severed precursor web 35 is held pressed to the support surface 41 by the pressing arrangement 110. By keeping the pressure P on the severed precursor web 35, any tensioned elastic in the precursor web 35 is prevented from contracting and causing damage to the newly formed side seams 6a, 6b. Cooling of the severed precursor web 35 may be carried out by exposure to ambient air only. It is also conceivable to use a cooling arrangement such as cooled air, or cooling elements arranged in the support roll within the cooling section 137.

[0120] At the end of the cooling section 137, the severed and cooled precursor web 35 reaches a take-off section 138 with a take-off arrangement 139. The take-off arrangement 139 is shown in FIG. 7 as a rotating suction roll. The take-off arrangement 139 is configured to remove individual pant-type garments 1 from the support roll 40. When the individual pant-type garments 1 have been separated from the precursor web 35, any elastic material such as elastic laminate webs, waist elastic and leg elastic in the pant-type garments 1 is no longer held in a stretched state. Thereby, the elastic will cause the pant-type garments 1 to gather, i.e. to contract and form rugosities or wrinkles in non-elastic or less elastic web material which is bonded to the elastic components.

EXAMPLES

[0121] Tested Material

[0122] The tested materials were ultrasonic bonded elastic materials having outer spunbond propylene nonwoven layers having a basis weight of 16 gsm (grams per square meter) and an elastic film of an ethylene based copolymer from Exten SA (Extretch MD2) The film was stretched to a stretch ratio of approximately 1:3 and bonded with ultrasonic bonds to outer nonwoven layers having a bond area of about 5%.

[0123] Test

[0124] Sample width 25 mm, sample length adapted to product to be tested. Samples 37 were taken across the side seam on the left and the right side of the pant-type garment, as illustrated by FIG. 11.

[0125] Equipment [0126] Tensile tester Instron 5965 with System ID 5965L3520  Software criteria for programming of break: [0127] Crosshead speed: 300 mm/min [0128] A break is detected when the load drops to 0.02 N or when it drops to 5% of the maximum load. [0129] Load with 2 s delay or detector becomes active at 1 N. [0130] Load cell within the measurement test area. If unsure, always start with a high max load cell of at least 100 N. [0131] Results: Maximum load, Type of break  The width of the plates of the clamps: 25 mm. The clamps must be as wide as or wider than the sample width.  Distance between clamps: around 25-50 mm [0132] Cutter with rotating knife or punching tool. [0133] When punching, punch templates of 25 mm in width, the length might vary due to which product to be tested.

[0134] Sample Preparation [0135] Punch or cut out test strips from desired parts of the side seams, making sure that the elastics are stretched before the samples are punched by using a stretching plate. Make sure not to overstretch the product.

[0136] Procedure [0137] Start up and zero/balance the tensile tester. See apparatus instruction. [0138] Set the distance between the clamps. [0139] Make sure the load is zero before every sample is mounted in the tensile tester. [0140] Fasten the test strip 37 with the side seam 6 of fused material between the clamps 34 in the tensile tester, according to FIG. 12. [0141] Start the pulling. [0142] Stop when the layers have separated. [0143] Note the maximum value=F (N) and if it there was a break in the sealing or in the materials outside the sealing.

TABLE-US-00001 TABLE 1 Side seam strength test data Waist right Waist left Middle right Middle left (N/25/mm) (N/25/mm) (N/25/mm) (N/25/mm) 21.82 25.14 25.82 23.44 22.53 20.89 28.12 26.31 21.09 23.3 24.57 31.22 26.18 25.51 25.07 22.31 25.76 18.18 23.29 23.08 Average: 23.5 22.6 25.4 25.3 Stdev: 2.3 3.1 1.8 3.7

[0144] Test Method Material Thickness

[0145] Principle

[0146] Thickness is defined as the dimension between two surfaces of an object, all materials included. The thickness is determined by means of a measuring foot with a fixed load which is lowered onto the sample at a given rate. The thickness is read off at the digital thickness gauge/tester after 5 seconds when the measuring foot has touched the surface of the sample.

[0147] Equipment

[0148] Thickness gauge/tester, model DT-25 supplied by IM-Teknik AB, Reningsverksgatan 6, 421 47 Västra Frölunda, accuracy ±0.03 mm.

TABLE-US-00002 TABLE 2 Square measuring foot Area 20 cm.sup.2 (45 mm × 45 mm) Foot weight: 103 g Force 1.0 N/20 cm.sup.2 = 0.05 N/cm.sup.2 Speed 13 mm/s ± 1 mm/s

[0149] For stretching of the samples a stretching equipment was used with a first, stationary clamp and a second clamp, the second clamp being movable within a frame such that the sample can be stretched in a longitudinal direction between the clamps. A force measuring device was attached to the movable clamp to measure the load force. The force measuring device may e.g. be a dynamometer.

[0150] Sample Preparation

[0151] Handle the products carefully when determining thickness to receive comparable results. Cut out a sample perpendicular to the side seam. A pair of scissors or a punch tool can be used. The sample should be 50 mm wide and minimum 150 mm long.

[0152] Procedure

[0153] Unfold the front panel and the back panel from each other and fix the ends in the stretching clamps. Stretch the sample till 10 N. (at this load the material was stretched to about 100% i.e. the stretch ratio 1:2)

[0154] Place the intended measuring surface under the measuring foot. The outer, garment-facing nonwoven layer should be arranged facing upwards towards the measuring foot.

[0155] Lower the measuring foot and when the foot touches the surface of the product wait 5 seconds but not longer before reading the result on the display.

[0156] Note! Avoid measure over folds and wrinkles.

[0157] Thickness Test Results

[0158] Ten comparable samples were cut across a welded seam between two pieces of the tested material and the material thickness and the seam thickness were measured. The average material thickness of the samples was 0.7 millimeters with a standard deviation of 0.09. The average seam thickness of the samples was 0.73 millimeters with a standard deviation of 0.07. The ratio t.sub.s/t.sub.m between the seam thickness t.sub.s and the material thickness t.sub.m was determined to be 1.06 with a standard deviation of 0.15.

[0159] Hence, the seam thickness t.sub.s as determined by the thickness of the side seam 6 was found to be slightly greater than the material thickness t.sub.m of the adjoining material 17 and to protrude somewhat from the garment-facing surface of the stretched tested samples as illustrated by FIG. 13 where a sample is shown attached between two clamps 34.