WO2013180610A1

WO2013180610A1 - Method for obtaining a substantially non-gathered panel region on an absorbent article

Info

Publication number: WO2013180610A1
Application number: PCT/SE2012/050585
Authority: WO
Inventors: Solgun Drevik
Original assignee: Sca Hygiene Products Ab
Priority date: 2012-05-31
Filing date: 2012-05-31
Publication date: 2013-12-05

Abstract

A method is described for obtaining a substantially non-gathered panel region on an absorbent article (10). The article includes an elastic laminate (42) comprising: an outer nonwoven layer (44) comprising a panel region (12) having a perimeter; a film layer (46) overlying the panel region (12) of the outer nonwoven layer (44), and an inner nonwoven layer (48) overlying the outer nonwoven layer such that the film layer (46) is interposed between the inner nonwoven layer and the outer nonwoven layer. The inner nonwoven layer (48) is provided with elastic members (50) secured to the inner nonwoven layer at locations (56) outside of the panel region (12). At least a first of the elastic members extends over the panel region. The method comprises the steps of: providing the elastic laminate (42) in an extended condition; severing the at least a first of the elastic members (50) at a severing location (58) overlying the panel region (12) to impart a substantially non- gathered condition to the panel region, and applying a liquid-repelling means (68) to the severing location (58) to inhibit liquid transmission through the elastic laminate (42) at the severing location (58).

Description

Method for obtaining a substantially non-gathered panel region on an absorbent article

TECHNICAL FIELD

The present invention relaters to a method for obtaining a substantially non-gathered panel region on an absorbent article.

BACKGROUND OF THE INVENTION

In order to improve the comfort and fit of absorbent articles, such as adult and infant diapers and pull-up pants-type diapers, it is common to make use of elastic sheets and/or laminates in the construction of the diapers. A typical such elastic sheet is made from a web of nonwoven material to which elastic members, such as elastic yarns, in an extended condition are affixed at intervals. When the elastic members are allowed to contract to a non-extended condition, the elastic members will gather the nonwoven web. An elastic sheet of this kind may be applied in an extended condition to further layers of material, such as a film layer or a further nonwoven layer, to form an elastic laminate.

A diaper generally comprises a front panel, a rear panel and a crotch region between the front panel and the rear panel. Since pants-type diapers need an elasticated waist opening to sit securely on a wearer, it is particularly advantageous if the front and/or rear panels of such garments employ the above-mentioned elastic sheets and/or laminates. In such constructions, the elastic members extend crosswise over the panels in a transverse direction. An absorbent core is secured to the crotch region. To prevent bunching of the core, the crotch region is generally kept free of elastic members.

A desirable characteristic of absorbent articles is that they do not leak. Thus, a liquid- impervious layer is normally placed over the garment-facing side of the absorbent core. In articles, such as pants-type diapers, in which the absorbent core extends over the front and rear panels, the liquid-impervious layer may be constituted by a film layer of the elastic laminate.

In order to make absorbent articles more aesthetically pleasing, it is known to provide the garment-facing side with a motif in the form of a fancy pattern, pictures or text such as "back" or "front". In those articles in which the liquid-impervious layer is constituted by a film layer, the motif may advantageously be printed or otherwise incorporated on the garment-facing side of the film layer. In the front and/or rear panels the film layer may thus be incorporated as a component of the elastic laminate. However, the elastic members of the elastic laminate will gather the laminate, including the film layer, thereby distorting the motif. To the extent that the absorbent core is attached to the front and/or rear panels, the absorbent core will be gathered, too.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a method for obtaining a substantially non-gathered panel region on an absorbent article whilst retaining adequate fit and leakage resistance.

In accordance with the present invention, this object is achieved by a method for obtaining a substantially non-gathered panel region on an absorbent article, the article including an elastic laminate comprising an outer nonwoven layer comprising a panel region having a perimeter; a film layer overlying the panel region of the outer nonwoven layer, and an inner nonwoven layer overlying the outer nonwoven layer such that the film layer is interposed between the inner nonwoven layer and the outer nonwoven layer. The inner nonwoven layer is provided with elastic members secured to the inner nonwoven layer at locations outside of the panel region, with at least a first of the elastic members extending over the panel region. The method comprises the steps of:

providing the elastic laminate in an extended condition;

severing the at least a first of the elastic members at a severing location overlying the panel region to impart a substantially non-gathered condition to the panel region, and applying a liquid-repelling means to the severing location to inhibit liquid transmission through the elastic laminate at the severing location.

Since, in accordance with the invention, the elastic members that extend over the panel region are secured to the inner nonwoven layer at locations outside of the panel region, when the elastic members are severed at the severing locations they will "snap back", thereby leaving the panel region substantially non-gathered. In this respect, the expression "substantially non-gathered" means that the severed elastic members do not impart any gathering force to the panel region, though it is not excluded that other, non- severed, elastic members may cause some gathering of the panel region. Furthermore, since the act of severing the elastic members may be detrimental to the liquid

impermeability of the elastic laminate, the method according to the invention includes the step of applying a liquid repelling means to the severing locations to inhibit liquid transmission through the elastic laminate.

In one aspect of the invention, the step of severing the at least a first of the elastic members is effected using cutting means extending through the inner nonwoven layer and into the film layer to make lacerations in the inner nonwoven layer and the film layer at the severing location. These lacerations occupy a first zone of the substantially non-gathered panel region which has a first extension in a transverse direction. The cutting means may be one or more rotary cutters.

In exemplary embodiments the liquid-repelling means may be constituted by a hotmelt adhesive. Although the adhesive may be applied intermittently to the elastic laminate, it may be advantageous if the hotmelt adhesive is applied as a continuous strip to the severing location such that the continuous strip covers the first zone. To ensure that all of the lacerations are covered, at the same time that excessive amounts of adhesive are avoided, the continuous strip of adhesive may have a transverse extension that is no more than five, preferably no more than three, times the first extension of the first zone. Thus, it is not necessary to cover the entire panel region with adhesive. A suitable means for applying the hotmelt adhesive is a non-contact slot coater.

In exemplary embodiments the elastic members are elastic yarn. When a plurality of elastic members is to be severed to impart a substantially non-gathered condition to the panel region, each of the elastic members will be associated with a respective severing location. However, one laceration may sever one or more elastic members.

To reduce the likelihood of any elastic members not being severed in the first zone, in one embodiment each elastic member is associated with two severing locations, a first of which having lacerations that occupy the first zone and a second of which has lacerations that occupy a second zone of the non-gathered panel region.

The method of the invention is eminently suitable for use with a pants-type diaper having a front panel, a rear panel and a crotch region between the front panel and the rear panel. In such a case, the non-gathered panel region can constitute a portion of the front panel and/or the rear panel. Suitably, the severing locations are distributed over the portion of the front panel and/or rear panel towards the crotch region.

In exemplary embodiments the pants-type diaper comprises an absorbent insert affixed to the crotch region, with the absorbent insert comprising a liquid-permeable topsheet, an absorbent core and a backsheet. The backsheet may comprise liquid-impermeable material at least in the crotch region.

The appearance of the absorbent article may be enhanced when the film layer of the elastic laminate bears a motif and the motif is visible through the outer nonwoven layer. Similarly, the same or a different motif may be borne by the liquid-impermeable material of the backsheet at least in the crotch region.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in the following by way of example only and with reference to the attached drawings, in which

Fig. 1 is a schematic perspective view of a pants-type diaper provided with a

substantially non-gathered panel region obtained using a method according to the present invention;

Fig. 2 is a plan view of the diaper of Fig. 1 when laid open and with its absorbent insert removed; Fig. 3 is a cross-sectional view through an absorbent insert used in the pants-type diaper of Fig. 1 ;

Fig. 4 is a cross-sectional view through a substantially non-gathered panel region;

Figs. 5A to 5D are schematic plan views of various severing location possibilities, and

Fig. 6 is a plan view of a portion of a substantially non-gathered panel region having a continuous strip of liquid-repelling means. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Principles underlying the present invention will be described in the following with reference to exemplary embodiments applied to a pants-type diaper. It is to be

understood, however, that the invention is applicable to any absorbent article on which a substantially non-gathered panel region is desired.

In the drawings, reference number 10 generally denotes a pants-type absorbent article having a substantially non-gathered panel region 12. The diaper 10 has a front panel 14, a rear panel 16 and a crotch region 18 extending between the front panel and the rear panel. The pants-type diaper is created by bringing the front panel 14 into overlapping relationship with the rear panel 16 and forming side seams 20 along transverse edges of the respective panels. As is known in the art, such side seams may be formed by ultrasonic welding or thermobonding. The thus-formed diaper 10 has a continuous waist opening 22, with the side seams 20 extending in a longitudinal direction to a pair of leg openings 24. As is indicated in Fig. 1 , an absorbent insert 26 is affixed to the crotch region 18 of the diaper.

For the sake of clarity, the absorbent insert 26 is omitted in Fig. 2. However, Fig. 3 illustrates a transverse cross-section through a suitable absorbent insert. The absorbent insert 26 includes a liquid-permeable topsheet 28, for example of a nonwoven material or a perforated plastic film, an absorbent core 30 and a backsheet 32. In the illustrated embodiment, the backsheet 32 is in the form of a laminate comprising an outer layer 34 of nonwoven material and an inner layer 36 of liquid-impermeable material, such as a plastic film. The liquid-impermeable material is present at least in the crotch region of the article. The absorbent core 30 is enveloped by the topsheet material, and the topsheet material may form lateral pockets 38 provided with elastic elements 40 to create upstanding waste containment barriers when the article is worn.

The absorbent article of the present invention includes an elastic laminate 42. With particular reference to Fig. 2, the elastic laminate is used in the front panel 14 and the rear panel 16. The construction of the elastic laminate 42 is apparent from Fig. 4 and includes an outer nonwoven layer 44, a film layer 46 and an inner nonwoven layer 48. The inner nonwoven layer overlies the outer nonwoven layer such that the film layer is interposed between the inner nonwoven layer and the outer nonwoven layer. The film layer 46 is generally visible through each of the inner and outer nonwoven layers, and its outline is shown in Figs. 1 and 2 as a continuous line 49. To impart elasticity to the elastic laminate 42, the inner nonwoven layer 48 is provided with elastic members 50, for example elastic yarns, which are affixed at spaced locations to the inner nonwoven layer whilst in an extended condition. Upon contraction of the elastic members the elastic laminate will 5 gather to form gatherings. Typical such gatherings are schematically illustrated in Fig. 1 and denoted by reference number 52.

Although the elastic laminate to which the method of the invention is applied has nonwoven layers, it will be understood that the claimed method steps may, in other 10 circumstances, be used on elastic laminates in which either or both of the inner and outer layers is/are constituted by a vapour-permeable film or woven web.

In the article illustrated in Figs. 1 and 2, the substantially non-gathered panel region 12 constitutes a portion of both the front panel 14 and the rear panel 16, though it is to be

15 understood that the invention is applicable to absorbent articles in which the substantially non-gathered region constitutes a portion of only one of the front and rear panels. Each substantially non-gathered panel region 12 has a perimeter 54 which delimits the area of the panel region on which no elastic members 50 act directly. In other words, the locations at which the elastic members 50 are affixed to the inner nonwoven layer 48 are all outside

20 of the perimeter. In the embodiment of Figs. 1 and 2, the perimeter is just within the

outline 49 of the film layer 46 of the elastic laminate. Thus, there are a number of elastic members which cross the film layer 46 at end regions of the film layer directed towards the waist opening 22. The innermost of these elastic members constitutes a portion of the perimeter of the substantially non-gathered panel region. In Fig. 4, two locations 56 are

25 shown at which elastic members 50 are affixed to the inner non-woven layer 48, these two locations 56 being within the outline 49 of the film layer 46. The two locations 46 also constitute portions of the perimeter of the substantially non-gathered panel region.

To obtain the substantially non-gathered panel region or regions 12, the elastic laminate 30 42 is provided in an extended condition such that substantially no gatherings are present.

A panel region which is to remain substantially non-gathered after the elastic laminate returns to its non-extended condition is created by severing any elastic members which extend over the desired non-gathered panel region at respective severing locations, generally denoted by reference number 58 in the drawings. The act of severing the elastic 35 members will cause the elastic members to "snap back" to the nearest locations at which the elastic members are affixed to the inner nonwoven layer, such locations by definition being outside of the substantially non-gathered panel region.

The elastic members may be severed using any suitable cutting means, such as a bladed instrument, a laser beam or a water jet. A particularly suitable cutting means is a rotary cutter, schematically illustrated in Fig. 4 in dashed lines and denoted reference number 60. At each severing location 58, the cutting means 60 extends through the inner nonwoven layer 48 and into the film layer 46 to make lacerations 62 therein. With reference to Figs. 5A to 5D, the lacerations 62 occupy a first zone 64 of the non- gathered panel region which has a first extension x in a transverse direction. The lacerations may be oriented in the longitudinal direction essentially perpendicular to the transverse extension of the elastic members 50, as indicated in Figs. 5A to 5C, or they may form an acute angle to the transverse extension of the elastic members, as indicated in Figs. 2, 5D and 6. A suitable angle has been found to be from 20° to 70°.

In addition to a first zone 64 of lacerations 62, a second zone 66 of lacerations is shown in Figs. 4 and 5B. By way of example, the first zone 64 has lacerations 62 which extend through the entire film layer, whilst in the second zone 66, the lacerations extend only partially into the film layer 46. The first and second zones 64, 66 extend over the non- gathered panel region towards the crotch region 18 of the absorbent article.

Since the thus made lacerations 62 may provide a route for the passage of liquid from the absorbent insert 26 outwards through the elastic laminate 42, in accordance with the present invention a liquid-repelling means 68 is applied to the severing location 58. The liquid-repelling means is any substance that will inhibit the transmission of liquid through the elastic laminate at the severing locations. Such substances include waxes, varnishes, adhesives and hydrophobic coatings. Due to their amorphous nature, such substances may be applied by printing, coating or spraying. A particularly suitable substance is a hotmelt adhesive, such as that sold under the trade designation LC 3001 ZP by H.B. Fuller. As depicted in Fig. 6, the hotmelt adhesive 68 is applied as a continuous strip to the severing locations 58 such that the continuous strip covers the first zone which is occupied by the lacerations. The continuous strip has a transverse extension y which is greater than the first extension x of the first zone. To ensure that the lacerations are adequately coated, the continuous strip should extend a transverse distance either side of the lacerations. Thus, the transverse extension y may be at least 5 mm greater than the first extension x, particularly for embodiments in which the first zone is of the type illustrated in Fig. 5c. Nevertheless, to reduce the amount of adhesive used as liquid- repelling means, the transverse extension y should not be more than 20 mm greater than the first extension x. Preferably, the transverse extension y of the continuous strip is no more than five times, preferably no more than three times, the first extension x of the first zone. Suitably, the continuous strip of hotmelt adhesive may be applied using a non- contact slot coater. In the embodiment illustrated in Fig. 5D, a typical range of values for the first extension x of the first zone is 5mm to 10 mm. The continuous strip of hotmelt adhesive may then have a transverse extension y of 15 mm to 30 mm.

In exemplary embodiments the film layer 46 of the elastic laminate 42 bears a motif 70 (see Fig. 1) that is visible through the outer nonwoven layer 44. In the substantially non- gathered panel region 12 the motif will also be substantially non-gathered. This can enhance the aesthetic appeal of the absorbent article. The motif 70 may be printed or incorporated in any suitable manner on the film layer 46. Similarly, the liquid-impermeable material 36 of the backsheet in the crotch region 18 may also be provided with a motif 72. Preferably, the motif 70 on the film layer 76 and the motif 72 in the crotch region visually complement each other and may be identical.

The present invention has been described above by way of exemplary embodiments only and the skilled person will appreciate that various modifications are conceivable within the scope of the appended claims.

Claims

A method for obtaining a substantially non-gathered panel region on an absorbent article (10), the article including an elastic laminate (42) comprising:

an outer nonwoven layer (44) comprising a panel region (12) having a perimeter;

a film layer (46) overlying said panel region (12) of said outer nonwoven layer (44), and

an inner nonwoven layer (48) overlying said outer nonwoven layer such that said film layer (46) is interposed between said inner nonwoven layer and said outer nonwoven layer, said inner nonwoven layer (48) being provided with elastic members (50) secured to said inner nonwoven layer at locations (56) outside of said panel region (12), at least a first of said elastic members extending over said panel region,

said method comprising the steps of:

providing said elastic laminate (42) in an extended condition;

severing said at least a first of said elastic members (50) at a severing location (58) overlying said panel region (12) to impart a substantially non- gathered condition to said panel region, and

applying a liquid-repelling means (68) to said severing location (58) to inhibit liquid transmission through said elastic laminate (42) at said severing location (58).

The method as claimed in claim 1 , wherein said step of severing said at least a first of said elastic members (50) is effected using cutting means (60) extending through said inner nonwoven layer (48) and into said film layer (46) to make lacerations (62) in said inner nonwoven layer and said film layer at said severing location, said lacerations occupying a first zone (64) of said non-gathered panel region which has a first extension (x) in a transverse direction.

The method as claimed in claim 2, wherein said cutting means (60) is at least one rotary cutter.

4. The method as claimed in any one of the preceding claims, wherein said liquid- repelling means (68) is a hotmelt adhesive. The method as claimed in claim 4, wherein said hotmelt adhesive is applied as a continuous strip to said severing location such that said continuous strip covers said zone, said continuous strip having a transverse extension (y) that is no more than five times, preferably no more than three times, said first extension (x) of said first zone.

6. The method as claimed in claim 5, wherein said continuous strip of hotmelt

adhesive is applied using a non-contact slot coater.

The method as claimed in any one of the preceding claims, wherein said at least first of said elastic members (50) is an elastic yarn.

The method as claimed in any one of the preceding claims, wherein said at least first of said elastic members (50) is a plurality of elastic members, each of said plurality being associated with a respective severing location (58).

The method as claimed in claim 8, wherein each of said plurality of elastic members (50) is associated with two severing locations (58), a first of said two locations having lacerations (62) that occupy said first zone (64) and a second of said two severing locations having lacerations occupying a second zone (66) of said non-gathered panel region (12).

10. The method as claimed in any one of the preceding claims, wherein said

absorbent article (10) is a pants type diaper having a front panel (14), a rear panel (16) and a crotch region (18) between said front panel and said rear panel, and said substantially non-gathered panel region (12) constitutes a portion of said front panel (14) and/or said rear panel (16).

1 1. The method as claimed in claim 10 when dependent on claim 8 or 9, wherein said first and second zones (64; 66) extend over said portion of said front panel and/or rear panel towards said crotch region (18).

12. The method as claimed in claim 1 1 or 12, wherein said pants type diaper

comprises an absorbent insert (26) affixed to said crotch region (18), said absorbent insert comprising a liquid-permeable topsheet (28), an absorbent core (30) and a backsheet (32), said backsheet comprising liquid-impermeable material at least in said crotch region.

13. The method as claimed in any one of the preceding claims, wherein said film layer (46) of said elastic laminate bears a motif (70), the motif being visible through said outer nonwoven layer (44).

14. The method as claimed in claim 13 when dependent on claim 12, wherein said liquid-impermeable material of said backsheet (32) at least in said crotch region bears a motif (72).