WO2016000009A1

WO2016000009A1 - Diaper and method and apparatus for the manufacture thereof

Info

Publication number: WO2016000009A1
Application number: PCT/AU2014/000676
Authority: WO
Inventors: Kylie BRIDGES; Kenneth W. BESTER JR.; Rodney BUTLER
Original assignee: Kimberly Clark Worldwide Inc; Kimberly Clark Corp
Current assignee: Kimberly Clark Worldwide Inc; Kimberly Clark Corp
Priority date: 2014-06-30
Filing date: 2014-06-30
Publication date: 2016-01-07
Anticipated expiration: 2016-12-30

Abstract

A method and a machine (10) to produce a diaper (11). The machine (30) delivers a waistband (18) including an elastic assembly (21) to the body of the diaper (11) so that the elastic assembly (21) relaxes to cause the waistband portion (20) of the waist band (18) to "bunch up" thereby improving the feel in respect of the user.

Description

DIAPER AND METHOD AND APPARATUS FOR THE MANUFACTURE THEREOF

FIELD

[0001 ] The present invention relates to absorbent articles that are intended to be worn, and more particularly but not exclusively to disposable diapers.

BACKGROUND

[0002] Absorbent articles that are intended to be worn include diapers, training pants, diaper pants and adult incontinence products. As an example, the diapers may be provided with fastening tabs that enable the diaper to be attached to the wearer. However the disposable diapers may also, in configuration, resemble underpants.

[0003] Typically the absorbent articles include a liquid permeable inner layer to face the wearer, a liquid impermeable outer layer, with an absorbent body disposed therebetween. The absorbent articles also include a waist region that encircles the wearer, with the waist region including an elastic waistband. The waistband needs to be soft as it engages the wearer, but also needs to be able to exert sufficient force to hold the diaper securel in position, in that regard elastic materials are optimised for efficiency by obtaining the maximum stretch without breaking. However this has the disadvantage that it creates an overpowered waistband that detracts from the user's comfort.

[0004] In diapers where securing tabs are employed, usually the tabs are not formed of elastic material. Such waistbands suffer from the disadvantage that they fail to deliver a secure fit, waist gasketing, and detract from the wearer's comfort.

[0005] Still further to the above, where the securings tabs are used, the tabs have the same transverse width as the waistband. This construction has the disadvantage that the waistband overpowers the chassis of the diaper, causing the diaper to wrinkle. This in turn makes the diaper harder to apply. OBJECT OF THE INVENTION

[0006] It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages.

SUMMARY OF INVENTION

[0007] There is disclosed herein an absorbent article for personnel wear about a user's waist, the article comprising;

a liquid permeable inner surface for facing the wearer;

an outer surface for facing away from the wearer;

an absorbent body disposed between the surfaces;

a waist region to at least substantially encompass the wearer, the waist region including an elongated elastic assembly to extend longitudinally along the waist region, the assembly including elongated elastic members having a maximum resilient extended length, and a substantial inelastic member that is elongated so as to extend longitudinally with elastic members and being secured thereto; and wherein

the elastic assembly is secured with respect to the surfaces so that the elastic member cannot be extended to said maximum resilient extended length, said assembly having a thickness Xmm when at said maximum resilient extended length, and a thickness Yram when applied to said body, with the ratio of Y.\X being at least 1.25.

[0008] Preferably, the ratio is at least 1.5.

[0009] .Preferably, the ratio is at least 2.0.

[0010] Preferably, the ratio is at least 4.0.

[001 1] Preferably, said ratio is from 1.25 to 5.0.

[0012] Preferably, said ratio is from 1.5 to 5.0.

[0013] Preferably, said ratio is from 2.0 to 5.0.

[0014] Preferably, said ratio is from 1.5 to 4.0. [00 ! 5] Preferably, said ratio is from 2,0 to 4.0,

[00 i 6] Preferably, the outer surface is provided by an outer layer, and the inner surface provided by an inner layer, with said elastic assembly being secured to the inner layer.

[0017] Preferably, the elastic members are elastic strands, and the inner member is a layer of fibrous non-woven material.

[0018] Preferably, the inelastic member includes a further layer of fibrous non-woven material, with the elastic strands located between the layers of the inelastic member.

[001 ] Preferably, the elastic assembly is secured with respect to the surfaces so as to be extendable to a maximum retracted length.

[0020] Preferably, the maximum retracted length is 60% to 90% of said maximum extended length.

[0021 ] There is further disclosed herein, a machine to provide discrete lengths of an elastic assembly, the assembly including at least one elongated elastic member secured to a

substantially inelastic member, the machine including:

a first rotatable member having a peripheral speed and to engage the assembly to deliver the assembly at a speed approximate said peripheral speed;

a second rotatable member, having a peripheral speed, that receives the assembly from the first rotatable member and engages the assembly to deliver the assembly at a speed approximate the peripheral speed of the second rotatable member;

a drive mechanism to cause rotation of the first and second rotatable members so that the peripheral speed of second rotatable member is less than the peripheral speed of first, rotatable member; and

an apparatus that receives the assembly from the second rotatable member, at.

substantially the same peripheral speed as the second rotatable member, with the apparatus operable to separate discrete lengths of the assembly from the assembly delivered to the apparatus. [0022] Preferably , the drive mechanism causes operati on of the first rotatabie member and the second rotatabie member so that the peripheral speed of the second rotatabie member is 60% to 90% of the peripheral speed of the first rotatabie member.

[0023] Preferably, the first rotatabie member includes a driven roller having a peripheral surface, and the second rotatabie member includes a driven roller with a peripheral surface, with the elastic assembly engaged by the peripheral surfaces of the rollers so as to be moved thereby.

[0024] There i further disclosed herein, a method of applying a waistband to a garment having a garment body, the method including the steps of:

providing a elongated elastic assembly having a maximum resilient extended length; delivering the assembly, by movement longitudinally of the assembly, to a first rotatabie member with the assembly at said maximum resilient extended length, the first member having a peripheral speed;

delivering the assembly from the first rotatabie member to a second rotatabie member, the second rotatabie member havi ng a peripheral speed less than the peripheral speed of the first rotatabie member;

receiving the assembly from the second rotatabie member at approximately the

peripheral speed of the second rotatabie and separating the assembly into discrete lengths while maintaining the discrete lengths tensioned as provided by the second rotatabie member; and applying a said discrete length to said body so that the discrete length when applied to said body have a maximum retracted length that is less than said maximum elastic extended length.

[0025] Preferably, the maximum retracted length is 60% to 90% of the maximum elastic extended length.

BRIEF DESCRIPTION OF DRAWINGS

[0026] Preferred forms of the present invention will no be described by way of example with reference to the accompanying drawings wherein:

[0027] Figure 1 is a schematic side elevation of a machine to aid in the manufacture of disposable diapers; [0028] Figure 2 is a schematic side elevation of the machine of Figure 1 ;

[0029] Figure 3 is a schematic plan view of a diaper manufactured by the machine of Figures 1 and 2.; and

[0030] Figure 4 is a schematic, sectioned enlarged view of portion of an elastic assembly of the diaper of Figure 3.

DESCRIPTION OF EMBODIMENTS

[0031] In the accompanying drawings there is schematically depicted a machine 10 to produce the disposable diaper 1 1 of Figures 3 and 4.

[0032] The diaper f I has an outer liquid impervious layer 12 that provides an outer surface that faces away from the wearer. Secured to the layer 12 is an inner layer 13 that is liquid pervious and that is substantially coextensive with respect to the layer 12. The layer 12 provides an inner surface to face the wearer. Located between the layers 12 and 13 is an absorbent pad 14. The layers 12 and 13, and pad 14 provide a body for the. diaper 1 j .

[ 0033 j in this embodiment the diaper 1 1 includes securing tabs 15 that are releasabiy securable to front waist engagement portions 16 so as to retain the diaper 1 1 around the waist of the wearer. However it should be appreciated that the present invention is also applicable to other absorbent articles, such as adult incontinence garments, and training pants. For example the training pants may be in the configuration of underpants.

[0034] In this embodiment the diaper 1.1 has longitudinally extending containment flaps 17 that are preferably elasttcized.

[0035] The diaper 1 1 has a waistband 18 that includes a front waistband portion 1 and back waistband portion 20. The waistband portions 19 and 20 are secured together by means of the tabs 15 so that the waistband portions 19 and 20 substantially enclose the waist of the wearer. Where the diaper 1 1 is in the form of underpants, the portion 1 and 20 are fixed together to from the waistband 18. [0036] Secured to the layer 13 is an elastic assembly 21. The assembly 21 is longitudinally elongated in the direction 22 that is generally transverse of the longitudinal axis 23 of the diaper 1 1. The layer 13 is to the assembly 2 attached by any suitable means, such as an adhesive or thermal bonding, as examples.

[0037] The assembly 21 includes a plurality of elastic members (strands) 24 that extend longitudinall in the direction 22, and a substantially inelastic member 25 that is secured to the members 24. When not forming part of the diaper 1 1 the assembly 21 is longitudinally elasticaliy deformable to a maximum length. At this maximum length, the members 24 are at their maximum elastic extension, that is they are stretched to "stop¹'. Elongation beyond "stop" results in destruction of the assembly 21 by breakage and/or decoupling of the components forming the assembly 21 , such as the members 24 and 25. In one preferred form the assembly includes layers of fibrous nonwoven material with a plurality of elastic strands (members .24) sandwiched between the nonwoven layers and secured to the outer layer of the non-woven material. The layers of nonwoven material provide the member 25. When extended to the maximum length described, the assembly 21 is essentially flat.

[0038] The assembly 21 is a discrete length of a supply of the assembly 21 taken from a roll. [0039] The assembly 21 is located so as to be adjacent the wearer.

[0040] In this embodiment that tabs 15 are secured to the end extremities of the assembly 21 , at overlapping: regions 26 by means of an adhesive. Accordingly a user may grip the tabs 1 and longitudinally extend the assembly 21 when applying the tabs 15 to the portions 16 to secure the diaper 1 1 to a wearer.

[0041] When forming part of the diaper 1 1 , the assembly 21 is prevented from reaching the abovementioned maximum length. This is achieved by having the assembly 21 attached to the layer 13 in a partly relaxed state. In that respect it should be appreciated the layer 1.3 is substantially elasticaliy inextensible relative to the assembly 21.

[0042] The machine 10 includes a base 30 that supports a fust rotatable member 3 1. The rotatable member 1 of thi embodiment is a motor and roller, however it should be appreciated that other rotatable members may be employed such as belts that are rotatahiy driven about an endless loop. Cooperating with the rotatable member 31 is a "nip" roller 32. The nip roller 32 is urged toward the roller 31.

[0043] A length of the assembly 21 is delivered to the rotatable member 31 from a supply thereof. The supply may come from a roll. The assembly may also be made "on line". The length of the assembly 21 delivered, to the rotatable member 31 is tensioned so that the assembly 21 is at the abovementioned maximum length.

[0044] The roller 32, by bei g urged towards the rotatable member 31 , maintains the a sembly 21 in secure contact with the rotatable member 31. In that respect it should be appreciated the rotatable member 31 is rotatably driven so as to have a predetermined peripheral speed. That is the surface of the rotatable member 31 that engages the assembly 21 has this predetermined peripheral speed. Where there is no slipage between the assembly 21 and member 31 , the assembly 21 will have that peripheral speed.

[0045] Upon leaving the rotatable member 31 , the assembly 21 passes about a plurality of idler rollers 33 as well an adhesive applicator 34 that applies a length of adhesive 35 to the assembly 21. to provide for securing of the assembly 21 to the inner surface of the layer 13. After passing the adhesive applicator 34, the assembly 21 passes about a second rotatable member 36 also fixed to the base 30. In this embodiment the rotatable member 36 is a motor and roller, howeve it should also be appreciated the rotatable member 36 may also be a belt driven about an endless loop. The rotatable member 36 has an outer peripheral surface that engages the assembly 21. The outer peripheral surface of the rotatable member 36 has a peripheral speed that is less than the peripheral speed of the rotatable member 31. This results in a retraction of the assembly 21 to a length and state of tension which is les than the length and tension of the assembly upstream (adjacent) of the rotatable member 31 ,

[0046] Accordingly the assembly 21 after leaving the rotatable member 1 is at least partly relaxed so as to not be at its maximum length that is discussed above.

[0047] After the rotatable member 36, the assembly 2 is engaged by a vacuum drive belt 37 that provides for the delivery of the assembly 21 to an apparatus 38 that delivers and fixes discrete lengths of the assembly 21 to the diaper 1 1, The apparatus 38 is fully described in USA Patent 5716478 and incorporated herein by reference. [0048] The apparatus 38, in cooperation with a separation means, such as a rotating knife assembly 39, provides the discrete lengths of the assembly 21 by separating the discrete lengths from the length delivered by the belt 37.

[0049] The apparatus 38 includes a plurality of "pucks" 40 that are rotatab!y driven through complete revolutions about a generally central shaft 4.1. The pucks 40 are moved in the angular direction 42.

[0050] Each of the pucks 40 is mounted for angular movement about an axis 43 so that the di screte len gths of the assembly 21 are moved to an orientation at which they are generally transverse of the longitudinal axis 23 of the diaper 11, as best seen in Figure 3.

[0051] Accordingly from the initial engagement with a puck 40, the discrete lengths of the assembly 21 are rotated through 90° about an axis 43 for application to the layer 13.

[0052] As described in the abovementioiied USA patent, each puck 40 has applied to it a vacuum so that the discrete lengths of the assembly 21 are securel fixed to the pucks 40 so as to maintain this partly relaxed configuration- Accordingly when the discrete lengths of the assembly 21 are applied to the layer 13, the assembly 21 is at least parity elastic-ally elongated but is not at its abovementioiied maximum length.

[0053] The conveyor 48 transports the diapers 11 during their construction and has associated with it a pressure roller 44 that engages the layer 12 and urges the layers 12 and 13 into

engagement with the assembly 21. Each assembly 21 is pressured between the associated puck 40 and the roller 44 to ensure engagement of the adhesive when, as shown in. this embodiment, the assembly 21 is attached to the layer 13.

[0054] The conveyor 48 includes a pair of vacuum drive belts 45 that moves the conveyor 48 in the direction 46. hi that regard it should be appreciated the direction 46 is parallel to the axis 23 of the diaper 1 1.

[0055] To ensure that the rotatable members 3.1 and 36 have the correct peripheral speeds, there is provided a primary drive and control mechanism 50. The mechanism 50 is preferably adjustable so that the relative peripheral speeds of the rotatable members 1 and 3 may be altered to suit specific products. [0056] Preferably, the assembly 21 is a laminated structure including synthetic or natural rubber (elastic members 24). in preferred forms the elastic members 24 are Lycra (Registered

Trademark) with the members 24 being essentially elastic and bonded to the member 25 so that the assembly 21 is a bonded non- woven laminate.

[0057] In respect of the assembl y 21 , the inelastic member 25 may be as follows:

• 30gsm 100% Polypropylene using T- 198 fibers from FiberVisions in. a Bo ded Carded Web

• Manufacturer is Sandler AG; Schwarzenbach/Saale, Germany

» Sawabond 4185®; and the elastic members 24, they may be as follows:

• HyFit™ 470 deeitex T-837 fibers

• Manufacturer is I vista; Waynesboro, Virginia, US A

[0058] The elastic members 24 may be applied to the inelastic members 25 by means of an elastic adhesive such as a hot melt adhesive.

[0059] Preferably, the assembly 21 , when attached to the layer 13, is retracted in length by approximately 10% to 40% of the above described maximum length. That is the retracted length is 60% to 90% of the maximum length.

[0060] The rotatable member 36 will have a peripheral speed a percentage less than the peripheral speed of the rotatable member 31. This results in a corresponding percentage "overfeed" of the assembly 21 to the pucks 40, and therefore to the body of the diaper 10. For example, if the rotatable member 36 has a peripheral speed 20% less than the peripheral speed of the rotatable member 31 , then there wil l be about a 20% overfeed of the assembly 21 to the body of the diaper 10. This overfeed influences the degree to which the assembly 21 bimches as seen in Figure 4, and therefore increases the thickness 51 of the assembly 21, that is this overfeed influences the thickness 51 of the assembly 21 when in the diaper 10.

[0061] Preferably, the assembly 21 has a thickness 51 of Xmm when at the maximum resilient extended length, and a thickness 51 of Ymm when being applied to the body of the diaper 10. Preferably the overfeed thickness ratio of Y;X is at least 1 .25, or at least 1.5. In another preferred form, the overfeed thickness ratio is at least 2,0. In a further preferred form the ratio is at least 4.0. One factor influencing this ratio is the material forming the assembly 21.

[0062] To determine the thickness 5.1 of the assembly 21 , a length of the assembly 21 is placed on a supportin surface. A plate, typically in the form of a disk, is applied to the assembly 21 so that the assembly 21 is sandwiched between the supporting surface and the plate. A force is applied to the plate so as to apply a pressure of about 0.2psi (about 1 8kPa). This pressure is applied for approximately 10 minutes and the distance between the supporting surface and the plate is measured to provide the thickness. The disk has a diameter approximately equal to the transv erse width of the assemb l y 21.

[0063] In this speeification, including claims, where a thickness is mentioned, the thickness is determined as described above.

[0064] To determine the thickness 1 of the assembly 21 , when the assembly 21 has been applied to a diaper, the assembly 21 needs to be removed from the body of the diaper. This can be done by a variety of known means such as by a solvent or "freeze". A known method "blow of free spray" can be used. The spray product is applied to the assembly 21 until the assembly 1 is cold. This enables the assembly 21 to be gently removed.

The above described preferred embodiment has a number of advantages including allowing the waistband portion 20 to bunch up (so as to have the above described thickness ratio) thereby providing it with a better feel in respect of a user.

Claims

CLAIMS:

1. A absorbent article for personnel wear about a user's waist, the article comprising: a liquid permeable inner surface for facing the wearer;

an outer surface for facing away from the wearer;

an absorbent body disposed between the surfaces;

a waist region to at least substantially encompass the wearer; the waist region including an elongated elastic assembly to extend longitudinally along the waist region, the assembly including elongated elastic members having a maximum resilient extended length, and a substantial inelastic member that is elongated so as to extend longitudinally with elastic members and being secured thereto; and wherein

the elastic assembly is secured with respect to the surfaces so that the elastic member cannot be extended to said, maximum -resilient extended length, said assembly having a thickness Xmm when at said maximum resilient extended length, and a thickness Ymra when applied to said body, with the ratio of Y:X being at least 1.25

2. The absorbent article of claim , wherein the ratio is at least I .5.

3. The absorbent article of claim , wherein the ratio is at least 2.0.

4. The absorbent article of claim 1, the ratio is at least 4.0,

5. The absorbent article of claim 1 , wherein said ratio is from 1.25 to 5.0.

6. The absorbent article of claim 1, wherein said ratio is from 1.5 to 5.0.

7. The absorbent article of claim 1, wherein said ratio is from 2.0 to 5.0.

8. The absorbent article of claim 1 , wherein said ratio is from 1.5 to 4.0.

9. The absorbent article of claim 1, wherein said ratio is from 2.0 to 4.0.

10. The absorbent article of any one of claims .1 to 9, wherein tire outer surface is pro vided by an outer layer, and the inner surface provided by an inner layer, with said elastic assembly being secured to the inner layer.

1 1, The absorbent article of any one of claims I to 10, wherei n the elastic members are elastic strands, and the inner member is a layer of fibrous non-woven material.

12, The absorbent article of claim 1 1 , wherein the inelastic member includes a further layer of fi brous non- woven material, with the elastic strands located between the layers of the inelastic member,

13, The absorbent article of any one of claims 1 to 12, wherein the elastic assembly is secured with respect to the urfaces so as to be extendable to a maximum retracted length.

14. The absorbent article of claim 13, wherein the maximum retracted length is 60% to 90% of said maximum extended length.

15. A machine to provide discrete lengths of an elastic assembly, the assembly including at least one elongated elastic member secured to a substantially inelastic member, the machine including:

a first rotatable member ha ving a peripheral speed and to engage the assembly to deliver the assembly at a speed approximate said peripheral speed;

a drive mechanism to cause rotation of the first and second rotatable members so that the peripheral speed of second rotatable member is less than the peripheral speed of first rotatable member; and

an apparatus that receives the assembly from the second rotatable member, at

substantially the same peripheral speed as the second rotatable member, with the apparatus operable to separate discrete lengths of the assembly from the assembly delivered to the apparatus.

16. The machine of claim 15 , the drive mechanism causes operation of the first rotatable member and the second rotatable member so that the peripheral speed of the second rotatable member is 60% to 90% of the peripheral speed of the first rotatable member.

17. The machine of claim. 15 or 16, when the first rotatable member includes a driven roller having a peripheral surface, and die second rotatable member includes a driven roller with a peripheral surface, with the elastic assembly engaged by the peripheral surfaces of the rollers so as to be moved thereby.

18. A method of applying a waistband to a garment having a garment body, the method including the steps of:

providing an elongated elastic assembly having a maximum resilient extended length; delivering the assembly, by movement longitudinally of the assembly, to a first rotatable member with the assembly at said maximum resilient extended length, the first member having a peripheral speed;

delivering the assembly from the first rotatable member to a second rotatable member, the second rotatable member having a peripheral speed less than the peripheral speed of the first rotatable member;

receiving the assembly from the second rotatable member at approximately the peripheral speed of the second rotatable and separating the assembly into di screte lengths whi le maintaining the discrete lengths tensioned as provided by the second rotatable member; and applyin a said discrete length to said body so that the discrete length when applied to said body have a maximum retracted length that is less than said maximum elastic extended length..

19. The method of claim 18, wherein the maximum retracted length is 60% to 90% of the maximum elastic extended length.