Absorbent article with high toughness adhesive

Abstract

The present invention discloses an absorbent article (20, 20') comprising a top sheet (58), a back sheet (42, 60) and an absorbent core (62) and at least one nonwoven-nonwoven adhesive bond in addition to the core stabilizing bond, wherein the adhesive of the adhesive bond has an adhesive strength of at least 11 MJ / m 3 The adhesive may also have a storage modulus G' of at least 7.5 MPa. These are measured at 37°C according to the method described herein. The adhesive comprises at least 5% tackifier by weight of the adhesive.

Description

Technical Field

[0001] The present disclosure relates to disposable absorbent articles, particularly pant diapers and taped diapers, which include at least nonwoven-nonwoven adhesive bonds. The adhesive provides nonwoven-nonwoven bonds that are particularly resistant to peel creep forces. Background Art

[0002] Disposable personal hygiene absorbent articles, such as baby diapers, training pants and adult incontinence products, have become irreplaceable for receiving and retaining body discharges such as urine or feces from incontinent persons. These absorbent articles include a liquid-permeable top sheet facing the wearer's body internally, a liquid-impermeable back sheet facing the outside, and an absorbent layer interposed between the top sheet and the back sheet. Other components are usually present in absorbent articles, such as fluid acquisition and / or distribution layers, inner and outer barrier leg cuffs, elastic components, core wraps, etc.

[0003] Typical absorbent articles include pant-type diapers that have side seams and are pulled up over the legs of the wearer similar to underwear. A particular type of pant design currently available on the market is sometimes referred to as a "balloon" pant. The balloon pant design typically includes a central absorbent base structure and an elastic band. The elastic band is typically relatively wide (in the longitudinal direction) and elastically stretchable in the lateral direction. It completely surrounds the wearer's waist and thereby covers a relatively large portion of the wearer's skin and constitutes a relatively large portion of the visible outer surface of the pants. The central base structure portion is typically joined to the inside of the front drawstring, the belt turns between the thighs under the wearer's lower body, and joined to the inside of the back drawstring. Therefore, balloon pants are a collection of separate product components.

[0004] Other common absorbent articles include taped diapers, which include two rear ears with strips that can be fastened to a landing zone provided at the front of the diaper to form a waist opening and leg openings. Typically, the strips have a plurality of small hooks at their ends that can releasably engage with suitable receiving surfaces on a separate piece of material called a landing zone, which is provided at the front of the diaper (hook-type fasteners and loop-type fasteners). The landing zone is also a component of the diaper that needs to be securely attached to the backsheet of the diaper.

[0005] The components of absorbent articles must be bonded to each other directly or indirectly. Although thermal bonding or ultrasonic bonding are increasingly used in the industry, these non-adhesive bonding methods require higher basis weight materials and cannot be used for continuous bonding of large areas. Therefore, adhesive bonding of various substrates will remain used in absorbent articles in the future.

[0006] Hot melt adhesives are generally used to prepare adhesive bonds on absorbent articles. Hot melt adhesives are thermoplastic compositions that are solid at room temperature. When heated, they are converted into liquid or molten state, i.e., hot melt adhesives are open and can be applied to substrates. When some pressure is applied to the hot melt adhesive to the second substrate before the hot melt adhesive is cooled to the solid state again, an adhesive bond can be formed between the two substrates. Hot melt adhesives have an open time optimized for the intended use and realize permanent adhesive bonding of adherends. Conventional hot melt adhesives generally contain adhesive matrix polymers, adhesive tackifiers and optional waxes, plasticizers (oils) and other additives.

[0007] As is known in the art, hot melt adhesives may be applied by contact applicators, such as slot glue applicators, or non-contact applicators, such as spray or spiral applicators. Typical hot melt adhesives and their functions are described, for example, in US 5,026,756 (Arendt).

[0008] WO2017 / 106153A2 (Turner, P&G) discloses a trouser-type article in which the adhesive bond is formed by an adhesive substantially free of a tackifier. The tackifier-free adhesive comprises (i) an amorphous polyolefin composition and a heterophasic polyolefin composition comprising amorphous properties and crystalline properties.

[0009] WO2016 / 149252A1 (Stiehl et al., P&G) discloses an absorbent core comprising a polyurethane foam having a molecular weight of greater than about 1.2×10 6 The fibrous network structure formed by the composition with a storage modulus (G') of Pa.

[0010] US10,350,325 (Remmers et al., HB Fuller) discloses an adhesive composition for absorbent articles, the adhesive composition comprising a first propylene-based polymer having a Mw of no more than about 75,000 and a second polymer also propylene-based and having a Mw of at least about 100,000. The adhesive composition is used for at least two applications in disposable absorbent articles and is delivered via a melt bulk tank. The document discloses the use of a hot melt adhesive formulation to bond a backsheet film to a nonwoven or elastic attachment and for core stabilization, but not for other nonwoven-nonwoven bonds.

[0011] Some bonding parts in diapers need to withstand the harsh requirements related to "peeling creep", that is, being exposed to continuous peeling force at a temperature close to body temperature over an extended period of time. For example, the elastic band in a pant-type diaper is under continuous tension during use. Another example is a landing zone material, which is attached to the front side of the adhesive diaper and the rear ear strip is releasably fastened thereto during use. The peeling creep resistance of the bonding part can be measured by a static suspension test. It is found that the load applied in the "peeling" configuration is more damaging to the bonding part than the load applied in the "shearing" configuration. Since peeling creep is the most destructive load condition of the bonding part made of viscoelastic adhesives (such as polyolefin-based adhesives), the static suspension test in the peeling configuration ("peeling suspension test") is used as the most conservative test of the bonding part under viscoelastic conditions. If the actual use load of the bonding part is unknown, or if many different loads can occur simultaneously or subsequently (for example, due to the movement of the baby when wearing a diaper, or the baby attempts to open the bonding part with his hands by slowly peeling off the substrate and the shear force and peeling force that occur), then this is particularly useful. If a bond has good peel creep resistance, it will generally also survive all other typical use conditions and can be used for other bonds in the diaper.

[0012] It has also been found that the desired properties of adhesives for NW-NW bonds are very different from those for NW-film bonds. Thus, there is a need for adhesives that are particularly suitable for NW-NW bonds that require resistance to peel creep. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A perspective view of an example of a belt-type pant diaper.

[0014] Figure 2 Schematic plan view of a belt pant diaper front structure before joining the front and rear sections of the belt.

[0015] Figure 3 For along Figure 2 Schematic cross-sectional view of the first embodiment taken along line 3-3 in FIG.

[0016] Figure 4 For along Figure 2 Schematic cross-sectional view of a second embodiment along line 3-3 in FIG.

[0017] Figure 5 A perspective view of an exemplary taped diaper is shown in a closed configuration as it is worn by a wearer.

[0018] Figure 6 Shown is a flattened strip opening Figure 5 The side of the diaper that faces outwards.

[0019] Figure 7 Shown is a flattened strip opening Figure 5 The side of the diaper that faces inwards.

[0020] Figure 8 For Figure 7 An exemplary cross-sectional view of a diaper in FIG. Summary of the invention

[0021] In the first aspect, the present invention relates to an absorbent article comprising a top sheet, a back sheet and an absorbent core, and at least one nonwoven-nonwoven adhesive bond other than a core stabilizing bond, the bond using an adhesive having selected properties. The absorbent core is typically present in most absorbent articles, but may be optional, for example, for swim trunks. The present invention can be used to provide adhesive bonding between two nonwovens in pants diapers and adhesive diapers. At least one adhesive bond may be a bond that is subjected to creep peeling forces during use. For pants diapers, such high-demand adhesive bonds include a tape bond, a base structure and a tape bond, a waist fold bond, and a front and rear tape bond that forms the side seams of pants diapers. For adhesive diapers, such adhesive bonds include a landing zone and a back sheet outer cover bond. The adhesive of the present invention may also be used for other adhesive applications with lower requirements, such as any adhesive bonding between a top sheet and a collection layer, and / or between a collection layer and a core wrap of an absorbent core and / or between a top sheet and a core wrap of an absorbent core.

[0022] It was found that the 3 , preferably at least 22 MJ / m 3 The adhesive of the present invention having a toughness of at least 0.7 MPa and a yield stress of at least 1.0 MPa is particularly effective for nonwoven to nonwoven (NW-NW) adhesive bonds, particularly for such bonds that are subject to peel creep during diaper use, and more generally for any nonwoven-nonwoven bond. The adhesive of the present invention comprises at least 5% of a tackifier by weight of the adhesive. The adhesive may also have a storage modulus (G') of at least 3 MPa, preferably at least 7.5 MPa. These properties are measured at 37°C according to the methods described herein.

[0023] Thus, the present invention allows cost savings by reducing the amount of conventionally used adhesive and / or allows improved performance relative to conventional adhesives at the same usage levels.

[0024] Various non-limiting embodiments of the present disclosure will now be described in order to generally understand the structural principles, functions, manufacture and uses of the absorbent articles disclosed herein. One or more examples of these non-limiting embodiments are shown in the accompanying drawings. It will be appreciated by those of ordinary skill in the art that the absorbent articles described herein and shown in the accompanying drawings are non-limiting exemplary embodiments, and the scope of the various non-limiting embodiments of the present disclosure is fully defined by the claims. The features shown or described in conjunction with a non-limiting embodiment may be combined with the features of other non-limiting embodiments. Such modifications and variations are intended to be included within the scope of the present disclosure. DETAILED DESCRIPTION

[0025] The following explanation of terms may be used to understand the present disclosure.

[0026] As used herein, "absorbent article" or "personal hygiene absorbent article" refers to a device placed close to or adjacent to the wearer's body to absorb and contain various exudates discharged from the body. The absorbent articles of the present invention include taped diapers and pant diapers. Their sizes can be suitable for infants, young children or adults with incontinence. Although absorbent articles are disposable and usually discarded after use, they are preferably recycled or otherwise disposed of in an environmentally compatible manner.

[0027] The terms "elastic," "elastomeric," and "elastomeric" refer to materials that are typically capable of stretching to at least a 50% strain without breaking or rupturing, and that are capable of recovering substantially to their original dimensions after the deforming force is removed.

[0028] "Longitudinal" refers to the direction along the axis extending from the midpoint of the front waist edge to the midpoint of the back waist edge of the absorbent article (L1, L2 in the figure), and divides the absorbent article into left and right halves. "Transverse" refers to the direction perpendicular to the longitudinal line (T1, T2 in the figure).

[0029] The term "pants" or "pants diapers" refers to an absorbent article having a defined waist opening and a pair of leg openings, and which is placed on the wearer's body by inserting the legs into the leg openings and pulling the article up over the waist. A pant diaper comprises a central chassis having a top sheet, a back sheet, and an absorbent core, which is combined with a waistband having front and back bands. Although the terms "pants" or "pants diapers" are used herein, pants are also commonly referred to as "closed diapers", "pre-fastened diapers", "pull-on diapers", "training pants", and "diaper pants". Such pant diapers are used, for example, in Figure 1 Shown in.

[0030] The term "tape diaper" refers herein to an absorbent article that includes a strip, usually in the back half of the product, which can be refastenedly attached to a landing zone (usually in the front of the diaper) to create a waist opening and leg openings. Such taped diapers are, for example, Figures 5 to 7 Shown in.

[0031] As used herein, the terms "nonwoven", "nonwoven layer" or "nonwoven web" are used interchangeably, meaning an engineered fiber assembly that is primarily planar and has been given a designed level of structural integrity by physical and / or chemical means, but does not include weaving, knitting or papermaking (ISO 9092:2019 definition). Directed or randomly oriented fibers are bonded by friction and / or cohesion and / or adhesion. These fibers may be derived from natural or synthetic sources, and may be staple fibers or continuous filaments or fibers formed in situ. Commercially available fibers have a diameter range of less than about 0.001 mm to greater than about 0.2 mm, and they have several different forms, such as staple fibers (known as chemical staple fibers or chopped fibers), continuous single fibers (filaments or monofilaments), untwisted continuous filament bundles (tows) and twisted continuous filament bundles (yarns). Nonwoven webs can be formed by many methods, such as meltblowing, spunbonding, solution spinning, electrospinning, carding, and air-laid. The basis weight of nonwoven webs is usually expressed in grams per square meter (g / m 2 or gsm).

[0032] As used herein, "include" and "comprising" are open-ended terms, each specifying the presence of a component described thereafter, for example, but not excluding the presence of other features, for example, elements, steps or components known in the art or disclosed herein.

[0033] As used herein, "consisting essentially of limits the scope of a subject matter, such as that described in a claim, to the specified materials or steps, and to those materials or steps that do not materially affect the basic and novel characteristics of the subject matter. The term "consisting of further limits the scope to the specified elements, steps, or components.

[0034] As used herein, "substantially" means about the same or uniform, but allowing for or having minor fluctuations from a defined property, definition, etc. For example, small measurable or unmeasurable fluctuations in measured properties described herein (such as viscosity, melting point, etc.) may be caused by human error or method precision. Other fluctuations are caused by inherent variations in the manufacturing process, thermal history of the formulation, etc. Nonetheless, the compositions of the present invention will be considered to have substantially the reported properties.

[0035] Pants Diapers20

[0036] The absorbent article of the present invention may be a pant diaper. Figures 1 to 4A pant diaper 20 is shown including a central chassis 38 and a waistband 40 in a non-limiting manner. Pant diaper construction will be briefly discussed therein, recognizing that such constructions are known in the art. A more detailed description of a typical pant construction is disclosed, for example, in WO2017 / 173894 (P&G). The components of the chassis including the topsheet, backsheet, absorbent core, inner cuff, and outer cuff may be made of similar components as found in a taped diaper 20' and are discussed further below.

[0037] Figure 1 is a perspective view of an embodiment of a pant-type diaper 20. Figure 2 The side seams 80 are not provided and the flat uncontracted state Figure 1 Schematic plan view of the garment-facing surface of a pant-type diaper. Figure 2 As shown, the pant diaper 20 has a longitudinal axis L1 which notionally divides the pant into left and right halves, and a transverse axis T1 perpendicular to L1 which divides the pant into front and rear halves of equal length.

[0038] The pant diaper 20 has a top sheet 58 on its wearer-facing surface. The pant diaper also has a backsheet laminate comprising a fluid-impermeable film 60 and a nonwoven outer cover 42 on its garment-facing surface. The pant diaper can also be divided into a front region 26, a back region 28, and a crotch region 30 between the front region 26 and the back region 28. The front region 26 is defined by a front belt 84 and the back region 28 is defined by a back belt 86.

[0039] The front belt 84 and the back belt 86 together form a transversely extending annular elastic belt (hereinafter referred to as a "waistband"). The front belt 84 and the back belt 86 are joined at their transverse side edges by side seams 80 to form a waist opening 110 and two leg openings 120 with the central chassis 38. One or both of the front belt 84 and the back belt 86 can be disposed on the garment-facing surface of the central chassis 38, or alternatively disposed on the body-facing surface of the central chassis 38.

[0040] The pant diaper 20 includes a central chassis 38 disposed in the crotch region 30 and extending at least partially longitudinally to the front region 26 and the back region 28 of the pant diaper. The central chassis 38 also includes an absorbent core 62 for absorbing and containing body exudates, a fluid-impermeable backsheet film 60 at least partially laminated to a nonwoven outer cover 42 on the garment-facing side of the article, and a liquid-permeable topsheet 58.

[0041] The central chassis 38 has a generally rectangular shape with left and right longitudinally extending side edges 48 (hereinafter referred to as "side edges") and front and rear transversely extending end edges 50 (hereinafter referred to as "end edges"). The front belt 84 and the rear belt 86 generally overlap at least a portion of the central chassis 38.

[0042] The front waist piece 52 is the portion of the central infrastructure 38 that overlaps the front belt 84 of the pant diaper 20, and the back waist piece 54 is the portion of the central infrastructure that overlaps the back belt 96 in the back region 28. The crotch piece 56 is the portion of the central infrastructure 38 that is disposed in the crotch region 30 and therefore between the front waist piece 52 and the back waist piece 54. The front belt 84 and the back belt 86 are typically joined to the infrastructure 38 in the regions of the front waist piece 52 and the back waist piece 54, respectively, by an adhesive 72, thereby forming a base structure and belt bond in these regions, which may be an adhesive according to the present invention. In the accompanying drawings, the bonds and the adhesive that forms the bonds are shown by the same reference numerals.

[0043] The waistband 40 formed by the front belt 84 and the back belt 86 is used to dynamically generate the fit force and to distribute the forces dynamically generated during wearing. In this article, the term "proximal" is used to indicate that the position of the "proximal" portion is closer to the transverse centerline T1 of the article. Therefore, the proximal edge 90 of the waistband 40 is positioned closer to the transverse centerline T1 than the distal edge 88 of the belt. The front belt 84 and the back belt 86 can be joined to each other only at the side seams 80 to form a pant-type diaper with a waist opening 110 and two leg openings 120. Each leg opening can be opened by elastic from the front belt 84, the back belt 86, and any elastic cuffs ( Figures 1 to 5 The leg openings may also have elasticity around the perimeter of the leg openings in combination with a plurality of other components (not shown).

[0044] The front band 84 and the back band 86 may be continuous or discontinuous with each other in the crotch region 30. When the front band 84 and the back band 86 are discontinuous, there is no material covering the entire wearer-facing surface or garment-facing surface of the article, such as Figure 2 In other words, the waistband does not extend into the crotch panel 56 of the central chassis 38.

[0045] Front band 84 and back band 86 include inner band 94 and outer band 92 separately.Inner band 94 and outer band 92 are nonwovens normally.Due to the air permeability and softness of waistband 40, front band 84 and back band 86 can be provided with low thickness nonwoven material.Belt can comprise inner hydrophobic, non-stretchable nonwoven material and outer hydrophobic, non-stretchable nonwoven material.Elastic strand 96 can comprise one or more elastic strands, elastomeric film, elastomeric ribbon, elastomeric nonwoven fabric, elastomeric filament, elastomeric adhesive, elastomeric foam, scrim or their combination.Each in front band 84 and back band 86 can be made into laminate, and this laminate has multiple elastic strands 96 sandwiched between inner band 94 and outer band 92 to give elasticity in front zone 26 and back zone 28.In one embodiment, elastic strand 96 is extended in transverse direction to provide loop elastic belt when front band 84 and back band 86 are engaged. At least some of the elastic strands 96 extend substantially parallel to each other in the transverse direction. All elastic strands 96 may extend substantially parallel to each other in the transverse direction. Such articles may be economically manufactured.

[0046] The front belt 84 and the back belt 86 may be made of the same or different materials. The arrangement of the elastic strands 96 may also be different in the front and back belts, such as using different deniers, spacings, and forces for the strands in the front and back belts and in different longitudinal positions of the belts. The front belt 84 and / or the back belt 86 may be treated so that a certain area overlapping the front waist panel and / or the back waist panel of the central chassis 38 is de-elasticized. Removing elasticity from the area where the artwork is displayed may help with the visibility of the artwork.

[0047] The effective transverse width LW of the rear band 86 in the uncontracted state may be the same as the transverse width of the front band 84 in the same state. The so-called "effective transverse width" refers to the width that can be used to form the wearer-facing surface of the article. Each of the proximal edge 90 and the distal edge 88 of the front band 84 and the rear band 86 can be substantially parallel, such as Figure 2 as shown in .

[0048] The longitudinal length LB of the rear belt 86 between the rear distal edge 88B and the rear proximal edge 90B along the entire width LW of the rear belt 86 can be approximately the same as the longitudinal length LF of the front belt 84 between the front distal edge 88 and the front proximal edge 90. In such embodiments, the side seams 80 close the side edges of the front belt 84 and the rear belt 86 of the same length to form the article. Such articles can be economically manufactured.

[0049] Compared to the longitudinal length LF between the front distal edge 88F and the front proximal edge 90F of the front band 84, the back band 86 can have a larger longitudinal length LB between the rear distal edge 88B and the rear proximal edge 90B along its entire width LW. In such embodiments, when the pants-type diaper is assembled to form a waist opening 110 and leg openings 120, the pants-type diaper 20 is folded along the transverse centerline T1 so that the front distal edge 88F is aligned with the rear distal edge 88B. The front side edge is also aligned with the rear side edge. Then, the front band 84 and the back band 86 are engaged at their side edges to form a pair of side seams 80. However, the front proximal edge and the rear proximal edge 90 also may not be aligned with each other. The rear proximal edge 90B can be arranged to be closer to the transverse centerline T1 longitudinally than the front proximal edge 90F, so that the back band 86 extends beyond the front proximal edge 90F toward the crotch piece 56 of the central infrastructure 38. The rear proximal edge 90B of the rear belt 86 may not be joined to any part and therefore does not contain attachments. In this way, the proximal portion of the rear belt 86 provides a hip cover 95, such as Figure 1 as shown in .

[0050] Regardless of whether the longitudinal length LB of the rear belt 86 and the longitudinal length LF of the front belt 84 are the same, the entire longitudinal length LF of the belt side edge of the front belt 84 can be sewn with the belt side edge of the rear belt 86 to define a seam length LS. When the front belt 84 has a straight distal edge 88F and a proximal edge 90 that are substantially parallel to each other, the longitudinal length LF of the front belt 84 is equal to the seam length LS.

[0051] See also Figure 3 and Figure 4 The outer band 92 of the front band 84 and / or the back band 86 may be longer than the inner band 94 in the longitudinal direction toward the corresponding distal edge 88, and the end flaps of the outer band 92 may be folded on the distal end of the inner band 94 at the waist opening to form an outer band folded portion 93 at the front band and / or the back band.

[0052] The central infrastructure 38 comprises a backsheet. The backsheet is typically a laminate comprising a liquid-impermeable backsheet film 60 attached to a nonwoven outer covering 42. The nonwoven outer covering forms the garment-facing side of the backsheet. The nonwoven outer covering 42 is typically attached to the backsheet film 60 by spiral adhesive, wherein two layers are designated as the backsheet of the article. The nonwoven outer covering 42 therefore forms a portion of the garment-facing surface 22 of the pant-type diaper 20, and at least covers the crotch piece 56 of the central infrastructure 38. The nonwoven outer covering 42 can extend into and cover a portion of one or both of the front waist piece 52 and the back waist piece 54 of the central infrastructure 38.

[0053] Adhesive bonding part of pants diapers

[0054] The front belt 84 and the back belt 86 are typically joined to the front waist panel 52 and the back waist panel 54 of the central chassis 38, respectively, by the nonwoven outer cover 42. Figure 3 to Figure 4 As shown, the nonwoven outer cover 42 is disposed between the front belt 84 and the back belt 86 and the liquid-impermeable backsheet of the central chassis 38. The nonwoven outer cover 42 may be co-edged with the backsheet in the longitudinal direction at the front waist panel 52 and / or the back waist panel 54, such as Figure 4 The inner tape 94 is attached to the nonwoven outer cover 42 of the backsheet in this area by the chassis and tape bonds 72.

[0055] The nonwoven outer covering 42 may also extend only partially in the longitudinal direction of the front waist panel 52 and / or the back waist panel 54 so that the distal portion of the front waist panel 52 and / or the back waist panel 54 does not contain the nonwoven outer covering 42, such as Figure 3 As shown. That is, the longitudinal length of the nonwoven outer covering 42 may be longer than the longitudinal length of the crotch region 30, but shorter than the longitudinal length of the backsheet film 60. Through such a configuration, the distal portion of the front waist piece 52 and / or the back waist piece 54 lacks the nonwoven outer covering 42, thereby providing better breathability for the overall product. In addition, the printed graphics on the portion of the backsheet film 60 that is not covered by the nonwoven outer covering 42 may therefore be more visible on the clothing-facing side of the pant-type diaper, as explained in more detail in WO2017 / 173894. However, even in this case, a portion of the inner band 94 is still attached to the nonwoven outer covering 42 of the backsheet in this region by the base structure and the tape bonding portion 72, wherein the backsheet film 60 is attached to the rest of the inner band 94. Before forming the base structure and the tape bonding portion, the adhesive 72 is usually first applied to the inner band 94.

[0056] While the adhesives of the present invention can be used in a variety of bonding locations, it has been found that certain pant diaper bonding locations can particularly benefit from the adhesives of the present invention. Figure 3 to Figure 4 , and includes a tape bond 70 for bonding the inner tape 94 to the outer tape 92, a base structure to tape bond 72 between the inner tape 94 and the base structure 38 (particularly as Figure 4 The nonwoven outer cover 42 is bonded to the chassis 38 as shown, and optionally Figure 3 4 and 5. The belt fold 93 is bonded to both the nonwoven outer cover 42 and the backsheet film 60 as shown), the belt fold 93 is bonded to the waist fold bond 74 of the chassis 38 (particularly the portion of the chassis formed by the topsheet 58, as shown). Figure 3 to Figure 4 ) and the side seam 80 bonding portions that bond the side edges of the front belt 84 to the side edges of the rear belt 86 of the pant diaper.

[0057] In addition to the side seams 80, these adhesive bonds are shown Figure 3 to Figure 4. The substrate closest to the dotted line in the figure represents the substrate to which adhesive is generally applied first before other substrates are adhered thereto. For the tape bond 70 that bonds the inner tape 94 to the outer tape 92, the adhesive can therefore be applied to the inner tape 94 before the tape laminate having the outer tape 92 and the elastic strands 96 is formed. For the base structure to tape bond 72 between the inner tape 94 and the portion of the base structure 38 formed by the backsheet laminate 48-60, the adhesive can therefore be applied first to the inner tape 72. For the waist fold bond 74 that bonds the tape fold 93 to the base structure 38 (i.e., the portion of the base structure generally formed by the topsheet 58), the adhesive 74 can be applied to the fold 93 of the front tape 84 and the back tape 86. For the front tape 84 to back tape 86 bonds that form the side seams 80 of the pant diaper 20, there is no preference as to which substrate the adhesive is applied first.

[0058] At least one or two or more of the above-mentioned adhesive bonds are preferably formed from an adhesive having the claimed properties because these nonwoven-to-nonwoven bonds are subject to creep peel forces during use of the diaper pants. In addition, other nonwoven-to-nonwoven bonds may benefit from the use of the claimed adhesive, in particular, the adhesive may also be used to bond the nonwoven acquisition layer 64 to the top sheet 58 (top sheet to acquisition layer bond 76) and / or to bond the acquisition layer 64 to the absorbent core 62 via its core wrap (acquisition layer to core wrap bond 78). If the acquisition layer 64 is not present, or if the acquisition layer is shorter than the core wrap, the adhesive may also be used to bond the top sheet 58 to the absorbent core 62 (the absorbent core typically includes a nonwoven core wrap, which is not separately shown in the diaper pants illustration, but is included in the taped diaper). Figure 8 16 and 16'). As is known in the art, the adhesive of the present invention can also be applied to, for example, elastic strands 96 when the elastic strands are disposed between inner belt 94 and outer belt 92, and to any other adhesive bonds not even shown in the figures. This also has the advantage of reducing the amount of adhesive raw material required to manufacture the diaper, thereby reducing complexity and cost.

[0059] Adhesive Diapers 20'

[0060] The present invention is also applicable to taped diapers which, unlike pants, include a pair of strips 41 on one side of the transverse axis T2 (usually the back side) which are refastenably attached to a landing zone 44 on the other side of the diaper (usually disposed on the front side of the diaper). The fastening system used in taped diapers allows the diaper to be closed around the waist and legs of the wearer. Once the diaper needs to be changed, the strips can be opened and the diaper can then be easily removed. The exemplary taped diaper 20' is Figures 5 to 8 Shown in. Figure 5 2 is a perspective view of an exemplary diaper in a closed state as it would appear when worn by a wearer. The taped diaper 20' is shown for illustration purposes only, as other taped diaper configurations exist. Unless expressly indicated to be so done, the drawings are used herein as an illustration of one way of carrying out the invention and do not limit the scope of the claims.

[0061] Taped diapers generally include a front edge 10, a rear edge 12 and two longitudinally extending side (lateral) edges 13, 14. The front edge 10 is the edge of the article that is intended to be placed toward the front of the user when worn, and the rear edge 12 is the opposite edge and together forms the waist opening of the diaper. When the diaper is closed, the lateral edges 13, 14 form two leg openings, respectively. The top sheet 24, the back sheet 25, the absorbent core 62 and other product components can be assembled in a variety of well-known configurations, in particular by gluing, melting and / or pressure bonding. The absorbent article of the present invention may include any typical layers and components for absorbent articles of the diaper type, and the layers and components are not necessarily simplified. Figures 5 to 8 The taped diaper may also be imaginarily divided by a longitudinal centerline L2 and a transverse centerline T2. The strip 41 is placed on a different side of T2 than the landing zone 44. The longitudinal axis and the transverse axis intersect at a point M which may be designated as the middle of the diaper.

[0062] Thus, the taped diaper 20' comprises a fastening system comprising a strip 41 and a landing zone 44. The landing zone is a component of the taped diaper adapted to receive and engage the strip 41. When fastened, the fastening system interconnects the front waist region and the rear waist region, thereby resulting in a fastening system that encircles the waist of the wearer during wear of the absorbent article. Various fastening systems have been proposed in the art, but generally the principle is based on the principle of The hook and loop principle is known in attachment systems. Specific examples of hooks (types and sizes) and landing zones are disclosed in WO2016 / 060922 (Jennewein et al.). Typically, the male element (hook) is provided on the belt and the female element (loop) is provided on the landing zone. The belt 41 is typically attached to the back ear 40' and the landing zone 44 is a separate piece of material, typically rectangular, which is attached to the backsheet at the front of the article, near the front waist edge 10. The back ear 40' is typically a stretchable laminate comprising an elastic film laminated to a nonwoven cover on each side.

[0063] While the claimed adhesives can be used for a variety of bonds in taped diapers, the invention is particularly useful for making a bond between a landing zone 44 and the nonwoven outer cover 42 of the backsheet, which is itself adhesively bonded to an impermeable backsheet film 60. In taped diapers, the backsheet film 60 and the nonwoven outer cover 42 of the backsheet are typically co-edged so that the landing zone 44 is adhesively bonded to the nonwoven outer cover 42. When the elastic back ear 40' is attached to the belt 41, this landing zone to backsheet bond is subject to elastic peel creep forces through the belt 41 along the perimeter of the diaper.

[0064] This landing zone to backsheet bond is particularly challenging with respect to the application process (applying adhesive onto the landing zone, cutting and sliding process steps using vacuum, difficult tension control, long distance between application and assembly points). As a result, there is greater variation in the microscopic application pattern, especially with respect to the transfer of adhesive from the first substrate to the second substrate (outer cover NW) and therefore with respect to the coating of the fibers of the second substrate. The claimed adhesive was found to have the correct inherent strength-related properties (G', yield stress and toughness) that are more tolerant to variations in the mass transferred to the second substrate at different lines and variations in the mass of the fiber coating of the second substrate. Imperfect fiber coating can be compensated by the excellent inherent strength-related properties of the adhesive.

[0065] Another possible application of the claimed adhesive is the bond 76 between the topsheet 58 and the acquisition layer 64. This is also a challenging joint with respect to the application process: the adhesive is typically applied to the topsheet, which is the primary substrate, via a slot. The diameter of the acquisition layer fibers is significantly larger than the diameter of the topsheet fibers (e.g., about 50 μm versus about 20 μm), which makes it more difficult to wrap these fibers with the adhesive. In addition, the acquisition layer is typically a very bulky and elastic substrate with a low bulk density (to meet its function of temporary liquid storage). Therefore, when the two substrates are combined, only a small portion of the acquisition layer fibers are available on the surface to form the bond. Therefore, an intrinsically stronger adhesive will also compensate to some extent for the change in mass transferred to the second substrate in this bond without the need to increase the basis weight of the adhesive. If the topsheet is partially separated from the acquisition layer during use, it will stick to the baby's buttocks, which is considered a negative experience by consumers.

[0066] Thus, the claimed adhesive may also be used to form the topsheet to acquisition layer bond 76. As previously indicated, the claimed adhesive may also be used to adhesively bond the acquisition layer 64 to the core wrap bond (acquisition layer to core wrap bond 78). The absorbent article may include an acquisition layer (as shown), but may also include an acquisition-distribution system comprising an acquisition layer and a distribution layer. In this case, the claimed adhesive may also be used to adhesively bond the acquisition layer and the distribution layer together. Although these bonds involving the topsheet, acquisition layer / distribution layer and core wrap are generally not subject to strong peel creep forces during use, unlike the landing zone to core cover bond, the claimed adhesive may still provide a stronger bond between these layers than conventional construction adhesives of the prior art. As previously discussed, the adhesive of the present invention may also be used to directly bond the topsheet to the core wrap, or in those portions of the core wrap where the acquisition layer is not present, or for those diapers where the acquisition layer is not present. The adhesive of the present invention may also be used to prepare any core stabilizing bonds (see below). Figure 8 Discussion), as long as the article includes at least one nonwoven-nonwoven adhesive bond in addition to the core stabilizing bond. In addition, reduced complexity is achieved by using the same glue material for different adhesive bonds.

[0067] Adhesives

[0068] The present invention is suitable for having high toughness parameter values ​​(at least 11 MJ / m at 37°C) 3 , and preferably at least 22 MJ / m at 37°C 3 ) and yield stress parameters (at least 0.7 MPa at 37°C, and preferably at least 1.0 MPa) and optionally any adhesive having a high storage modulus G' (at least 3 MPa at 37°C, and preferably at least 7.5 MPa at 37°C). The method for measuring toughness and yield stress (extensional rheology) enables the screening of adhesives for their resistance to large strains occurring under actual load conditions in use, which is in contrast to standard rheological adhesive tests such as oscillatory rheology (yield such as storage modulus G') that only study the behavior of adhesives under small deformations. Thus, toughness and yield stress provide key complementary information about storage modulus, which only describes the elastic resistance to initial small deformations and indicates the "stiffness" of the adhesive. The adhesive of the present invention is typically a hot melt adhesive.

[0069] The inventor finds that the combination of the minimum value of the toughness and yield stress of limitation can predict that polyolefin-based adhesive is for the construction bond portion, particularly has harsh use load requirement, and the nonwoven-nonwoven bond portion that particularly high peeling creep requires has enough inherent strength.Two parameters can be obtained from identical measurement.The inventor also finds that the storage modulus G ' that needs different methods can be used as the supplementary 3rd parameter of selection, and it also advantageously has minimum value.In a word, the adhesive according to the success of the present invention has 1) high toughness, namely dissipates deformation energy until the ability of failure on large deformation, 2) high yield stress, that is, only the plastic deformation that begins after the adhesive experience high stress and 3) optionally also has high rigidity.

[0070] The inventors have found that, in particular, the toughness parameter predicts the peel creep resistance in the construction bond and the creep resistance in the constant displacement test for elastic attachment adhesives. The inventors have also found that the toughness parameter indicates the use of adhesives to reduce potential. The higher the toughness parameter, the less adhesive the adhesive may use without compromising creep resistance. Although the inventors believe that there is no theoretical upper limit to toughness (e.g., up to 60MJ / m 3 ), but there may be an upper limit on the yield stress at 37°C (about 20 MPa) and G' at 37°C (about 50 MPa) because the adhesive may become too brittle.

[0071] The adhesive is typically applied at 0.5 g / m 2 Up to 30g / m 2 , especially 1.5g / m 2 Up to 25g / m 2 , more particularly 2g / m 2 Up to 20g / m 2 The average basis weight of the adhesive is applied in the bonding area. As known in the art, the hot melt adhesive can be applied by a contact application device, such as a slot glue application device, or a non-contact application device, such as a spray or a spiral application device. The slot glue application device applies the adhesive in a series of slots along the longitudinal direction separated by the gap. Usually, the slot width is the same as the gap width, for example 1mm, but this is certainly not restrictive. The average adhesive basis weight as used herein is calculated by dividing the total amount of glue by the entire bonding area, and the bonding area includes any gaps between the glue slots and any spacing between the spiral glue, as is common in the art.

[0072] Without being bound by theory, the inventor believes that in order to provide strong bonding between the first nonwoven and the second nonwoven, the adhesive should enable the formation of correct microscopic patterns in the bonding area, which can be described as the double-row entanglement of the adjacent fibers from the two nonwovens. Ideally, most of the fibers are embedded with 360 ° or at least 180 °. This forms a mechanical lock, in which the fibers are bonded. The inventor finds that the combination of the high toughness of this type of mechanical lock provided by this type of structure and adhesive can achieve a bond that resists peeling creep under use conditions.

[0073] Adhesive of the present invention is not limited to specific chemical substances. In its simplest form, adhesive of the present invention can be composed of polymer and tackifier. Tackifier can be a single tackifier or a blend of tackifiers as further discussed below. The specific adhesive composition of Licocene PP 2502 (propylene-ethylene-copolymer based on metallocene technology) and 16 wt % tackifier (Eastotac Resh H-100L or Escorez 5300) was prepared, and it was found that it has required characteristics, as shown in the following experimental section.

[0074] Adhesives comprising propylene-based polymers and tackifiers as described in US2014 / 0358100A1 (HB Fuller, Remmers et al.), especially Examples 2 and 4 of the publication, are also considered to be useful as adhesives in the present invention. The present disclosure indicates that the adhesive can be used in the core stabilizing bonds. The core stabilizing bonds are those bonds that ensure the structural integrity of the core, such as the longitudinal side seals and end seals of the core wrap, and any adhesive that at least partially fixes the absorbent material within the core wrap. The core stabilizing bonds do not include the bonds between the core wrap and another layer of the article (such as the backsheet, topsheet of the acquisition layer, which is not part of the absorbent core).

[0075] As taught in US2014 / 0358100A1, adhesive can include two or three different propylene-based polymers. Propylene-based polymers can be propylene homopolymers, or one or more of two different propylene-based polymers can be copolymers with one or more other monomers (e.g., ethylene, butene, pentene, octene, etc.). Propylene-based polymers can be completely based on olefins, i.e., do not contain any functional groups. Propylene-based polymers can include propylene greater than about 75% by weight or even greater than about 80% by weight of propylene. Propylene-based polymers can have a polydispersity (Mw / Mn) less than about 5, less than about 3 or even about 2. Propylene-based polymers can have a density not greater than about 0.89, or not greater than about 0.88.

[0076] It is believed that a suitable commercial adhesive according to the teachings of the present disclosure is NW1414 available from HB Fuller Company. This adhesive NW1414 has also been proposed in the past as a microfiber adhesive for superabsorbent particles, see WO2016 / 149252A1 (P&G, Stiehl et al.). The inventors have now found that this adhesive is also particularly suitable for NW-NW construction bonds with high peel creep requirements, such as those bonds pointed out in the Summary of the Invention.

[0077] Another commercial example of an adhesive found to meet the required properties is DM 4699 available from Henkel, which is also a polyolefin based formulation (the exact formulation is not disclosed).

[0078] The adhesive of the present invention may comprise at least one propylene-based polymer as the polymer backbone. Propylene-based polymers include polypropylene homopolymers, propylene-ethylene copolymers, and mixtures thereof. The propylene-based polymer may be the main component by weight of the adhesive, which may comprise at least 50% of the propylene-based polymer by weight of the adhesive composition. The adhesive may particularly comprise at least 60% of the propylene-based polymer by weight of the composition.

[0079] Although the above polymers (polypropylene homopolymer or propylene-ethylene copolymer) are generally useful for forming such inter-fiber locks, the inventors have found that not all such polymers provide the desired creep resistance between two nonwoven substrates. The inventors have found that the adhesive composition should also have certain mechanical properties designated as toughness and yield stress at the use temperature (measured at 37° C.), which will be shown below in the form of different examples.

[0080] Suitable metallocene-catalyzed propylene-ethylene copolymers can be polymers in the range Commercially available from Clariant, it has a wide range of properties such as molecular weight, viscosity, crystallinity, etc. US2016 / 053,149A1 assigned to Clariant also describes suitable copolymers and shows on page 5 that these examples are produced by the method shown in EP571,882. For a given catalyst system and a given comonomer ratio, the molecular weight is adjusted via the hydrogen partial pressure as a molar mass regulator.

[0081] It is believed that the crystallinity of the polymer, especially the propylene-based polymer, is a contributing factor to toughness. Propylene-based polymers, especially propylene-ethylene copolymers are advantageously semi-crystalline, having a melting enthalpy of at least 20 J / g as measured according to the melting enthalpy measurement method described herein. However, excessive crystallinity can make the adhesive composition brittle, so as measured according to the melting enthalpy measurement method described herein, the melting enthalpy can be advantageously less than 100 J / g, particularly less than 50 J / g.

[0082] Commercial examples of suitable propylene-ethylene copolymers are Clariant's PP 2502, which has a measured melting enthalpy of 29.4 J / g, or Clariant 3602, which has a measured melting enthalpy of 35.0 J / g. On the other hand, it is believed that the measured melting enthalpy of 15.1 J / g PP 1502 or a measured melting enthalpy of 16.7 J / g PP 1602 does not have sufficient crystallinity to be used alone.

[0083] The adhesive may include a first propylene-based polymer having an Mw (molecular weight) of at most about 75,000, at most about 60,000, at most about 50,000, or between about 30,000 and about 70,000, wherein the first propylene-based polymer may be present in the total composition in an amount of at least about 20 wt%, 25 wt%, or 30 wt%, or about 15 wt% to about 50 wt%, or about 25 wt% to about 45 wt%. Exemplary first polymers may include LICOCENE PP1602 and LICOCENE PP2602 available from Clariant International Ltd. (Muttenz, Switzerland) and L-MODU X400S and L-MODU X600S available from Idemitsu Kosan Co., Ltd. (Japan).

[0084] The composition may also include a second propylene-based polymer having an Mw of at least about 100,000, at least about 125,000, at least about 150,000, or between about 125,000 and about 400,000, or between about 150,000 and about 250,000. The second propylene-based polymer may be present in the composition in an amount of up to about 20 wt %, up to about 15 wt %, up to about 8 wt %, or about 2 wt % to about 15 wt %, or about 3 wt % to about 10 wt %. Exemplary second polymers may include VISTAMAXX 6202 and VISTAMAXX 6102 available from ExxonMobil Chemical (Houston, Texas) and VERSIFY 3300 available from Dow Chemical Company (Houston, Texas). The total propylene-based polymer content of the composition can be at least about 20 wt%, at least about 25 wt%, at least about 30 wt%, at least about 35 wt%, or from about 35 wt% to about 50 wt%.

[0085] The composition may include a third polymer, such as a styrene block copolymer, which may be hydrogenated. Available hydrogenated styrene block copolymers include, for example, styrene-ethylene / butadiene-styrene block copolymers, styrene-ethylene / propylene-styrene block copolymers, styrene-ethylene / ethylene-propylene-styrene block copolymers, and combinations thereof. The styrene block copolymer may have a styrene content of less than about 20 wt %, less than about 18 wt %, or even less than about 15 wt %. When tested according to ASTM 1238 (230° C., 5 kg), the styrene block copolymer may also have a melt flow of less than about 25 g / 10 min, less than about 20 g / 10 min, less than about 10 g / 10 min, or even less than about 5 g / 10 min. Exemplary hydrogenated styrene block copolymers are commercially available under a variety of trade names, including, for example, the SEPTON series of trade names from Kuraray Co., Ltd (Houston, Tex.), including, for example, SEPTON S2063 and S2007 hydrogenated styrene-isoprene-styrene block copolymers, and the KRATON G series of trade names from Kraton Performance Polymers Inc. (Houston, Tex.), including, for example, KRATON G 1645M, KRATON G 1657 styrene-ethylene / butadiene-styrene block copolymers. The material may include not more than about 20 wt%, not more than about 15 wt%, about 2 wt% to 20 wt%, or even about 5 wt% to 15 wt% of the third polymer.

[0086] The adhesive composition may comprise a blend of two, three or more polymers, in particular the adhesive composition may comprise:

[0087] - from about 15% to about 45% of a single site catalyzed and propylene-based low basis weight first polymer having a Mw of from about 30,000 to about 75,000; and

[0088] - from about 2% to about 15% of a propylene based second polymer having a Mw of from about 100,000 to about 400,000, and wherein the second polymer has a density no greater than 0.89.

[0089] The low molecular weight metallocene-catalyzed polymer may also comprise a blend of two copolymers, in particular:

[0090] - a first low molecular weight metallocene-catalyzed propylene-ethylene copolymer having a melting enthalpy below 20 J / g; and

[0091] - A second lowest molecular weight metallocene-catalyzed propylene-ethylene copolymer having a melting enthalpy above 20 J / g.

[0092] The first low molecular weight metallocene-catalyzed propylene-ethylene copolymer has a melting enthalpy of less than 20 J / g, specifically 5 J / g to 15 J / g, and can be described as low crystalline. A commercial example of the first copolymer is available from Clariant PP 1602. Licocene PP 1602 is sold as pellets and is described as a low melting, metallocene technology based propylene-ethylene copolymer which exhibits a low degree of crystallinity. The Mp of PP 1602 was measured to be 75,900 g / mol and its melting enthalpy was 16.7 J / g (see measurement method below). Another example is PP 1302. The Mp of PP 1302 was measured to be 24,100 g / mol and its enthalpy of melting was 11.8 J / g.

[0093] The second low molecular weight metallocene-catalyzed propylene-ethylene copolymer has a higher melting enthalpy than the first copolymer by at least 20 J / g, specifically 25 J / g to 45 J / g. Polymers in this range can be described as semi-crystalline. The second copolymer can have an Mp in the range of 50,000 g / mol to 130,000 g / mol, or 60,000 g / mol to 110,000 g / mol. Commercial examples of the second copolymer are PP 3602, which is sold as pellets and is described as a low crystalline metallocene catalyzed propylene-ethylene copolymer. 3602 has a measured enthalpy of melting of 35.0 J / g.

[0094] The first and second copolymers described above may be blended typically in a weight ratio of 10:90 to 90:10, such as 50:50 or 2:1 or 1:2. It was found that blending two lower molecular weight copolymers having different crystallinity can achieve low stiffness (as specifically required for NW film construction bonds) while still maintaining high toughness (as generally required for NW-NW and NW film construction bonds).

[0095] An example is 3602 and Licocene 3602 is a relatively highly crystalline polymer, while Licocene 1602 has a medium degree of crystallinity.

[0096] However, it is believed that melting enthalpy is not a unique relevant factor for predicting the good peeling creep resistance of the adhesive composition comprising a polymer. For example, the L-MODU S-410 of Idemitsu has a melting enthalpy of only about 2J / g of measurement, but it is believed that good performance can still be provided. The inventors believe that the performance of the adhesive is driven by the relatively high toughness measured as shown below. It is believed that this toughness is driven by the homopolymer properties of L-MODU S410 and the relatively high molecular weight (45.000g / mol) of the polymer. It is believed that toughness increases with the molecular weight of the polymer.

[0097] The propylene-based polymer comprises propylene monomer units. In the copolymer, the percentage of propylene monomer units may be, for example, in the range of 50% to 99% by weight of the copolymer. If the percentage of propylene monomer units is unknown, it may be determined by suitable methods known to those skilled in the art, such as nuclear magnetic resonance or infrared spectroscopy.

[0098] The polymer of the present invention can be prepared using a metallocene catalyst. The polymer can be prepared, for example, by the method described in US2016 / 0053149A1 ("Ready-to-use hot melt adhesive having an improved property profile"). The polymer can be prepared into a final polymer adhesive by heating the primary polymer to a high temperature (e.g., about 135°C to about 175°C) at which the polymer melts. Once melted, other ingredients (tackifiers, and, for example, additives or other polymer components) can be added to the primary polymer. A mixer can be used to mix the components together to form a final adhesive composition. See, for example, US5,723,546, which discloses such blending.

[0099] When using a polyolefin with a high peak molecular weight Mp of 130,000 g / mol to 700,000 g / mol, the toughness of the formulation can be significantly increased. The high molecular weight polyolefin can have a peak molecular weight of at least 10,000 g / mol, in particular at least 20,000 g / mol or even at least 50,000 g / mol greater than the peak molecular weight of the above-mentioned low molecular weight metallocene-catalyzed polymer (the highest value of the blend). The high molecular weight polyolefin can especially have a peak molecular weight of 140,000 g / mol to 410,000 g / mol, or 150,000 g / mol to 360,000 g / mol.

[0100] The inventors have surprisingly found that the addition of a longer molecular weight polyolefin significantly increases the strain hardening of the blend in addition to increasing the elongation at break, the combination of which results in significantly higher toughness of the formulation. Strain hardening is believed to be a "self-healing mechanism" of the blend upon strain, which avoids premature rupture.

[0101] High molecular weight polyolefin can be advantageously made of single material to simplify the compounding and preparation of hot melt composition, but does not exclude that it can also be the blend of the separate material belonging to this definition. Hot melt composition can comprise usually by the weight of hot melt composition 1% to 20%, particularly by the weight of hot melt composition 2% to 15%, especially 5% to 10% of this type of high molecular weight polyolefin (or their mixture). It is believed that a small amount of addition of longer molecular weight polyolefin can significantly enhance strain hardening and therefore strengthen toughness. On the other hand, viscosity can be increased by more than 10%. Toughness, strain hardening and elongation at break are measured and observed in the tensile test method, so that the adhesive is subjected to large deformation, such as relevant when the bonding portion is subjected to force in use.

[0102] The high molecular weight polyolefin can be a homopolymer or a copolymer. The copolymer can contain different alpha olefin monomers, such as ethylene, propylene, 4-methyl-1-pentene, pentene-1, 2-methylpentene-1, 3-methylbutene-1, heptene-1, dimethylpentene-1, trimethylbutene-1, ethylpentene-1, methylpentene-1, trimethylpentene-1, methylethylpentene-1, 1-octene, diethylbutene-1, propylpentane-1, decene-1, methylnonene-1, nonene-1, trimethylheptene-1, methylethylbutene-1, dodecene-1 and hexadecene-1, and combinations thereof.

[0103] Non-limiting examples of commercially available high molecular weight polyolefins are Affinity EG 8200G, Engage 8200, Infuse 9817, Vistamaxx 3000, Vistamaxx 6102, Vistamaxx 6202, Vistamaxx 6502, VERsify 4200, VERsify 4301.

[0104] The high molecular weight polyolefin can be a propylene-ethylene copolymer in particular. The high molecular weight polyolefin can also be a copolymer based on metallocene catalysis, in particular a metallocene catalyzed propylene-ethylene copolymer. The high molecular weight polyolefin can be a propylene-ethylene copolymer in particular, comprising more than 80% by weight of polypropylene units with isotactic stereochemistry. Examples of such copolymers can be commercially available from ExxonMobil as the Vistamaxx series. For example, Vistamaxx 6202 and Vistamaxx 6502 are sold in pellets and described by their manufacturers as being primarily composed of isotactic propylene repeating units with random ethylene distribution produced using metallocene catalyst technology. Vistamaxx 6202 and 6502 are used as high molecular weight polymers in the formulation product examples below. Vistamaxx 6502 has the lowest viscosity, and therefore has the least effect on increasing the viscosity of the total composition.

[0105] Tackifier

[0106] The adhesive of the present invention comprises at least 5% tackifier (or mixture of tackifiers) by weight of the adhesive. The word tackifier is used in the singular, but unless otherwise specified, this means "one or more tackifiers", because blends of tackifiers can also be used. The adhesive composition may comprise 10% to 70%, in particular 20% to 65%, or 25% to 60%, or 26% to 60%, or 30% to 60% tackifier by weight of the composition. Tackifiers, also known as "tackifier resins" or "tackifying resins", are low molecular weight compounds (oligomers) that are added to adhesive formulations to improve adhesion and peeling of adhesive materials. Commonly used tackifiers known in the art can be used in the present invention. Typical tackifiers are thermoplastic materials that are stable at least up to 200°C, are amorphous glasses at room temperature, and have a Tg higher than 50°C, preferably between 80°C and 125°C. Tackifiers typically have a molecular weight between 500 Daltons and 2000 Daltons.

[0107] Tackifiers are generally organic chemicals with a polycyclic structure. Commonly used tackifiers are selected from rosin resins and their derivatives (rosin esters), hydrocarbon resins produced from petroleum-based byproducts of naphtha crackers, and terpene resins (modified or unmodified). Hydrocarbon resins can be aliphatic, alicyclic and aromatic resins (particularly C5 aliphatic resins, C9 aromatic resins and C5 / C9 aliphatic / aromatic resins), and can optionally be hydrogenated hydrocarbon resins.

[0108] Exemplary tackifiers include aliphatic hydrocarbon resins, aromatic modified aliphatic hydrocarbon resins, hydrogenated polycyclopentadiene resins, polycyclopentadiene resins, gum rosin, gum rosin esters, wood rosin, wood rosin esters, tall oil rosin, tall oil rosin esters, polyterpenes, aromatic modified polyterpenes, terpene-phenolic resins, aromatic modified hydrogenated polycyclopentadiene resins, hydrogenated aliphatic resins, hydrogenated aliphatic aromatic resins, hydrogenated terpenes and modified terpenes, and hydrogenated rosin esters. Particularly suitable tackifiers are rosin (and its derivatives) resins and hydrogenated hydrocarbon tackifiers, which are solid at room temperature.

[0109] Benefits of using a tackifier include (i) increasing the open time of the adhesive, which generally enables better transfer to the second substrate during the lamination process, particularly when the process open time (defined as the distance between the applicator and the assembly point divided by the line speed) is short, and (ii) being able to increase the polarity of the adhesive, which helps to increase bond strength to more polymeric substrates (e.g., polyester fibers), particularly for bonds where optimal entanglement of the fibers is difficult to achieve.

[0110] In some embodiments, the tackifier has an Mw of less than 5,000 and a Tg above room temperature. Suitable tackifier classes include, for example, aromatic, aliphatic and alicyclic hydrocarbon resins, mixed aromatic and aliphatic modified hydrocarbon resins, aromatic modified aliphatic hydrocarbon resins, and hydrogenated forms thereof; terpenes, modified terpenes, and hydrogenated forms thereof; natural rosins, modified rosins, rosin esters, and hydrogenated forms thereof, and combinations thereof.

[0111] Suitable commercial tackifiers include, for example, the ESCOREZ series of trade names available from Exxon Mobil Chemical Company (Houston, Texas), including ESCOREZ 5400 and ESCOREZ 5600; the EASTOTAC series of trade names available from Eastman Chemical (Kingsport, Tenn.), including EASTOTAC H-100R and EASTOTAC H-100L; and the WINGTACK series of trade names available from Cray Valley HSC (Exton, Pa.), including WINGTACK 86, WINGTACKEXTRA, and WINTACK 95; and the PICCOTAC and KRISTALEX series of trade names available from Eastman Chemical Company (Kingsport, Tenn.), including, for example, PICCOTAC 8095 and KRISTALEX 3100.

[0112] The adhesive may also optionally contain additives such as one or more antioxidants, UV stabilizers, brighteners, colorants, fragrances, etc. The adhesive may contain less than 5% by weight of such additives. Any antioxidant known to those of ordinary skill in the art may be used in the adhesive composition.

[0113] Other parts of the product

[0114] As previously indicated, the absorbent article of the present invention, whether a pant diaper 20 or a taped diaper 20', may include any of the typical components found in these absorbent articles. The absorbent article includes a liquid permeable top sheet 58 on its wearer-facing side, a liquid impermeable back sheet film 60 on its garment-facing side, and an absorbent core 62 (whose contour is in the region of the top sheet and back sheet) disposed between the top sheet and back sheet. Figure 2 and Figure 6 to Figure 7 The top sheet is generally formed of a liquid permeable material, which allows liquid to easily penetrate its thickness. Any known top sheet may be used in the present invention, typically a nonwoven fabric that may or may not be perforated. Alternatively, an apertured formed film may be used, but this is uncommon in diaper applications. The backsheet generally includes a fluid-impermeable plastic film 60 that may be printed with a decorative backsheet pattern, and a low basis weight nonwoven outer covering 42 that is glued thereto. The nonwoven outer covering 42 provides a better feel and appearance to the backsheet.

[0115] The absorbent article may also include a fluid acquisition layer 64 and / or a fluid distribution layer between the top sheet and the absorbent core, and other typical diaper components such as elasticized gasketing cuffs 32, upright barrier leg cuffs 34, which are only Figure 8 , but are present in most diapers, including in the chassis of pant diapers. If it is desired to improve the performance of the article, the absorbent article may also include other common components, such as transverse barrier cuffs, front elastic waistbands and / or rear elastic waistbands (for taped diapers), lotion applications on the top sheet, longitudinally extending channels in the core and / or distribution layer, wetness indicators, etc. ... All of these components have been described and illustrated in the art and will not be further described in detail herein. More detailed disclosures of examples of such components are disclosed, for example, in WO201493323, WO2015 / 183669 (all Bianchi et al.), WO 2015 / 031225 (Roe et al.) or WO2016 / 133712 (Ehrnsperger et al.), to name a few.

[0116] The absorbent core 62 generally comprises an absorbent layer comprising superabsorbent particles sandwiched between a nonwoven top layer 16 and a nonwoven bottom layer 16' of a core wrap, such as Figure 8 As shown. Figure 3 to Figure 4 , but the absorbent core used in the taped diaper may have the same construction as the core in the pant diaper. The absorbent core typically includes core stabilizing bonds, which help maintain the structural integrity of the core. The core stabilizing bonds are the longitudinal side seals 82 of the core wrap and the core end seals (if present) (not shown), as well as any adhesive that at least partially secures the absorbent material within the core wrap, such as auxiliary glue 81 applied to the inside of the top or bottom layer of the core wrap. However, the core stabilizing bonds do not include a bond between the core and another layer of the article, such as a backsheet, topsheet of a collection layer that is not part of the absorbent core. For simplicity, not all adhesive bonds are shown in the figure, for example, the backsheet laminate bond between the membrane 60 and the nonwoven outer cover 42 is not shown.

[0117] Example

[0118] Table 1 discloses the melting enthalpy (in J / g) of some commercially available polymers that can be used in the present invention:

[0119] Table 1

[0120] Melting enthalpy Licocene PP 1302 11.8 Licocene PP 1602 16.7 Licocene PP 2502 29.4 Licocene PP 3602 35.0

[0121] As shown in Table 2, the following adhesive compositions were formulated (all numbers are in weight %). is a propylene-ethylene copolymer available from Clariant. Eastotac and Escorez are tackifiers available from Eastman and ExxonMobil, respectively. is a polypropylene polymer consisting primarily of isotactic propylene repeating units with random ethylene distribution available from ExxonMobil.

[0122] Table 2

[0123]

[0124] Experimental measurements

[0125] As shown in the Test Methods section below, the toughness, yield stress and G' of the exemplary adhesives as well as commercial adhesives were measured and the results are summarized below in Table 3. Of the commercial adhesives, NW1414 and DM4699 were found to meet the criteria of the present invention (Table 3), unlike D3166, DM3800, DM3522 and DM3442, which are commercial polyolefin-based adhesives used in absorbent articles (prior art).

[0126] Table 3

[0127]

[0128]

[0129] Some of these adhesives are available in 15.4 g / m 2 The basis weight of 1000 g was slot coated over the entire area between two nonwovens representing the landing zone to backsheet core cover bond in a converting line. The sample was hung with one nonwoven held in a vertical position and the other nonwoven attached with a weight of 150 g. For some of these adhesives, the delamination time ("peel hang time") was measured for a 45 mm bond length sample with a width of 40 mm, and the delamination time represents the resistance of the adhesive to peel creep forces.

[0130] Table 4

[0131]

[0132] This first set of data shows that NW1414 is significantly better for NW-NW bonding than the comparative examples. For the inventive examples, the measurement was stopped after 500 minutes without delamination.

[0133] In the following examples, adhesive is slot coated with 1mm gap between 1mm wide strip / strips with a specified basis weight (on the strips) between two nonwovens. When only half of the area is covered, the average basis weight over the entire area is half of the basis weight on the strips. For width, be 25.4mm and apply different 6mm bonding length samples of 150g of weight to measure the peeling hang time.

[0134] Table 5

[0135]

[0136] This second set of data demonstrates that the adhesives of the present invention have better resistance to peel creep forces than conventional prior art adhesives even at lower basis weights.

[0137] Test Method

[0138] Tensile test method

[0139] The tensile test method is used to determine the yield stress and toughness of samples of the polymer composition. Thin film samples formed from the polymer composition are analyzed using a rotational rheometer equipped with a special fixture with counter-rotating rollers, and the stress associated with the applied tensile strain is measured and recorded.

[0140] Instrument Setup

[0141] The rotational rheometer (ARES G2, TA Instruments, New Castle, DE, USA, or equivalent) is equipped with a fixture with counter-rotating cylindrical rollers specifically designed for interrogating the tensile deformation of the film. An example of a suitable fixture is an extensional viscosity fixture or EVF (EVF, TA Instruments, or equivalent). The rheometer is also equipped with a forced convection oven FCO (FCO, TA Instruments, or equivalent) and a cooling system (ACS2, TA Instruments, or equivalent) capable of controlling the temperature from at least -50°C to 250°C, within a tolerance of 0.5°C.

[0142] Sample preparation

[0143] Approximately 6 g ± 2 g of the polymer composition is placed in a round polytetrafluoroethylene (PTFE) bowl with a flat bottom (60 mm ± 2 mm diameter) and introduced into a vacuum oven maintained at 170° C. After 15 minutes at ambient pressure, the pressure is reduced to 10 mbar, and the polymer composition is then maintained at 170° C. and 10 mbar for 45 minutes to remove bubbles from the polymer composition. If 170° C. is not enough to melt the polymer composition, a temperature 30° C. ± 10° C. above the melting temperature of the polymer material composition is used. The polymer composition is removed from the vacuum oven and allowed to cool to ambient laboratory conditions (23° C. ± 2° C.) for 90 minutes ± 30 minutes, at which point the polymer composition is removed from the PTFE bowl and placed between 2 sheets of siliconized paper (such as product number 114918, Mondi Group, Hilm, Austria, or equivalent). A metal shim with a thickness of 500 μm ± 30 μm was used as a spacer in a hot press, and a film thickness of 500 μm was obtained when pressed with a hot press at 90°C for 60 seconds under a pressure sufficient to form a polymer film. If 90°C is not sufficient to press a uniform flat film, a temperature of about 10°C ± 5°C below the melting point of the sample material composition was used so that the sample material composition was in a semi-solid state. The film was stored in a laboratory at 23°C ± 2°C for at least 120 hours before testing. A single measurement sample was punched out of the film with a sample cutter so that the final sample size was 20.0 mm × 10.0 mm × 500 μm.

[0144] Measurement

[0145] To fix the sample film to the cylinder of EVF, in the forced convection oven of the rheometer, the cylinder is heated to 50°C for 90s±30s. After opening the oven, the sample of the polymer composition is briefly pressed on the cylinder of EVF to fix it to the cylinder surface. The sample is placed so that its length is perpendicular to the axis of rotation of the cylinder. For polymer compositions that are very hard and do not adhere to the cylinder surface, in the forced convection oven of the rheometer, EVF is heated to 80°C for 90s±30s. Then a small droplet (0.03g±0.01g) of the auxiliary hot melt adhesive is applied to each cylinder. The auxiliary adhesive used should show high hardness (G' of the auxiliary adhesive at 23°C and 1Hz is greater than 10MPa) so as not to interfere with the measurement. The sample of the polymer composition is quickly pressed on the auxiliary adhesive on the EVF cylinder to fix it to the cylinder surface. The sample is placed perpendicular to the axis of rotation of the cylinder.

[0146] The sample mounted on the EVF is then placed in the forced convection oven of the rheometer for thermal conditioning and maintained at 37°C ± 0.5°C for 300s ± 10s. After this period of time, the sample is mechanically conditioned. To mechanically condition the sample, the torque transducer is zeroed and the sample is moved at 0.001s -1 The pre-stretching rate is set at 0.30 s and then relaxed for 60 s (in this method, all strains are expressed as Hencky strain (also called "true strain" or "logarithmic strain")).

[0147] The measurements were performed in a FCO oven at 37°C ± 0.5°C. The strain rate for the measurements was 1 s -1 , and the strain at maximum stretch is 4.0. After the measurement, check whether the sample is broken. If broken, record the location of the break. If the break is approximately between the two cylinders of the EVF, the collected data is considered acceptable. Otherwise, if the polymer film break is located at or near the rotating cylinder, the result is discarded and the measurement is performed again on a duplicate sample.

[0148] analyze

[0149] For the tensile stress calculation, a constant volume is assumed. The tensile stress (in megapascals or MPa) is calculated versus the Hencky strain data from the raw torque versus angular displacement data recorded by the rheometer. The data are plotted semi-logarithmically with the Hencky strain on the abscissa (linear scale) and the tensile stress on the ordinate (logarithmic scale). A linear range is sought in this plot. If a linear range for strains above 0.3 can be identified and this range can be compared to R 2If a positive slope fit is found with a value of 0.98 or greater, the value of the fitted line at which the Hencky strain is zero (i.e., the y-intercept) is defined as the yield stress and is reported in MPa with an accuracy of kilopascals. Otherwise, the maximum value of the tensile stress recorded during the measurement is reported as the yield stress, again reported in MPa with an accuracy of kilopascals.

[0150] The tensile stress (MPa) versus Hencky strain data calculated above are again plotted, but this time linearly, with the Hencky strain on the abscissa (linear axis) and the tensile stress on the ordinate (linear axis). The integral of the tensile stress versus strain (i.e., the area under the tensile stress curve as a function of strain) is calculated from zero strain to the strain at which the sample ruptured (or to a strain of 4.0 if it did not rupture during the measurement) and is reported as "toughness" in megajoules per cubic meter or MJ / m 3 Report for the unit.

[0151] Oscillatory Rheological Test Methods

[0152] The oscillatory rheological test method is used to measure the storage modulus G' and loss factor of the polymer composition. A controlled strain rotational rheometer (such as Discovery HR-3, TA Instruments, New Castle, DE, USA, or equivalent) is capable of controlling the sample temperature (using a Peltier cooler and a resistive heater combination) over a range of at least -10°C to 150°C with an accuracy equal to or better than 0.5°C. The rheometer is operated in a parallel plate configuration with a 20 mm stainless steel parallel plate tool.

[0153] The method initially uses a parallel plate gap of 1000 μm. To compensate for thermal expansion of the tool, the gap is set to 1000 μm and a mapping of the actual plate gap (as measured using a suitable standard test fluid) as a function of temperature in the range of -10°C to 150°C is performed. This mapping is then used throughout the determination of the storage modulus parameters and the loss factor parameters.

[0154] The rheometer was heated to 150°C, the polymer composition was introduced into the rheometer, the gap was set to 1050 μm, the excess protruding sample was trimmed, and then the gap was set to 1000 μm. (The axial force control of the rheometer was set to 0 N and maintained within ±0.1 N of the force during the experiment, thereby compensating for the thermal expansion / contraction of the sample itself by adjusting the gap in addition to the compensation for the tool mentioned above, so as to avoid overfilling or underfilling.) The rheometer was then cooled to 130°C, at which time the temperature was reduced from 130°C to -10°C at a constant cooling rate of 2°C / min, and the measurement was started. The applied strain amplitude was 0.1%, and the oscillation frequency was 1 Hz (i.e., one cycle per second). The resulting oscillating stress was recorded.

[0155] After this step, the sample temperature was set to 23° C. (the temperature was increased to this setting at a rate of 10° C. / min) and the sample was allowed to stand for 4.0 hours at 23° C. At the end of this period, the temperature was set to -10° C. (the temperature was decreased to this setting at a rate of 10° C. / min), the sample was equilibrated at -10° C. for 300 seconds, and then a second oscillatory rheology measurement was performed (0.1% strain, oscillation frequency of 1 Hz) while the temperature was increased to 130° C. at a constant increase rate of 2° C. / min.

[0156] Starting from the first decreasing temperature scan, calculate and record the storage modulus G' at 37°C, and report these values ​​in Pascals (Pa) as "Storage Modulus at 100°C" to the nearest 1 Pa. Calculate and record the loss factor (also called loss tangent value) at 100°C starting from the first decreasing temperature scan, and report this dimensionless value as "Loss Factor at 100°C" to the nearest hundredth. The storage modulus G' may also be calculated and recorded at different temperatures (e.g., 100°C).

[0157] Melting enthalpy measurement method

[0158] The melting enthalpy of the hot melt adhesive composition is determined using the melting enthalpy test method, which consists of the following: ASTM D3418-15 is performed according to the following additional instructions. One or more hot melt samples are preferably extracted from the molded or pelletized raw adhesive composition. If no raw materials are available, one or more adhesive samples are extracted from the bond of interest in the absorbent article using techniques known to those skilled in the art. Dry nitrogen is used as a purge gas in a differential scanning calorimeter (DSC). The heating rate in the DSC is 10°C / minute, and the cooling rate in the DSC is 1°C / minute. The mass-normalized melting enthalpy is calculated based on the curve corresponding to the decreasing temperature (at 1°C / min) as specified in Section 11.4 and reported as "melting enthalpy" in Joules / gram (J / g), accurate to 0.1 J / g.

[0159] Molecular weight

[0160] The weight-average molecular weight Mw and the number-average molecular weight Mn are determined according to standard ISO 16014.

[0161] Miscellaneous

[0162] The claims may suitably comprise, consist of, consist essentially of, or be substantially free of any disclosed or recited elements. The invention illustratively disclosed herein may also suitably be practiced in the absence of any element not specifically disclosed herein.

[0163] It should be understood that the dimensions and values ​​disclosed herein are not intended to be strictly limited to the exact numerical values ​​cited. Instead, unless otherwise specified, each such dimension is intended to represent the stated value and a functionally equivalent range around that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm".

[0164] The relevant parts of all documents cited in the specific embodiments of the present invention are incorporated herein by reference; the reference to any document should not be interpreted as an admission that it is the prior art related to the present invention. When any meaning or definition of a term in the present invention conflicts with any meaning or definition of a term in a document incorporated by reference, the meaning or definition given to the term in the present invention shall be obeyed.

[0165] Although specific embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications may be made without departing from the spirit and scope of the present invention. Therefore, it is intended that all such changes and modifications within the scope of the present invention be covered in the appended claims.

Claims

1. An absorbent article comprising a topsheet (58), a backsheet, an absorbent core (62), an optional acquisition layer (64), and at least one nonwoven-to-nonwoven adhesive bond other than a core stabilizing bond, wherein the adhesive of the adhesive bond has an adhesive strength of at least 11.0 MJ / m 3 and a yield stress of 0.7 to 20 MPa, wherein the toughness and yield stress are measured according to the tensile test method at 37° C., and the adhesive comprises at least 5% of a tackifier by weight of the adhesive, wherein the adhesive has a storage modulus G' of up to 50 MPa, wherein the storage modulus G' is measured according to the oscillatory rheological test method at 37° C., The absorbent article is a pant-type diaper (20) having a front region (26), a back region (28) and a crotch region (30) disposed therebetween; the pant-type diaper comprises: - a central chassis (38) comprising a liquid permeable topsheet (58), a liquid impermeable backsheet comprising a liquid impermeable film (60) and a nonwoven outer cover (42), an absorbent core (62) having a core wrap disposed between the topsheet and the backsheet, and optionally an acquisition layer (64); - a waistband (40) arranged around the central chassis, covering the chassis to its outer side in the front and rear regions, overlapping and extending laterally and longitudinally outwards from the chassis; - wherein the waistband comprises a front band (84) and a rear band (86), the front band and the rear band each comprising an outer band (92), an inner band (94) and an elastic strand (96) therebetween; - wherein the front belt (84) has a front waist edge (88F), and front left and right edges; and the back belt (86) has a back waist edge (88B) and back left and right edges, wherein the respective front and back left edges and the respective front and back right edges are joined by side seam bonds (80) to form a waist opening (110) and left and right leg openings (120); - wherein the nonwoven-nonwoven adhesive bonds are selected from one or more of the following: i) a tape-tab bonding portion (70) that bonds the outer tape (92) to the inner tape (94); ii) a base structure to belt bonding portion (72), wherein the base structure to belt bonding portion bonds the inner belt (94) and the base structure (38); iii) a waist fold bond (74) bonding the belt fold (93) to the chassis (38); iv) the side seam bonding portion (80), the side seam bonding portion bonding the side edge of the front belt (84) and the side edge of the back belt (86); v) a bonding portion (76) between the top sheet and the acquisition layer; vi) an acquisition layer and core wrap bond (78); and vii) bonding portion between the top sheet and the core wrap; or, wherein the absorbent article is a taped diaper (20') comprising a liquid permeable topsheet (58), a liquid impermeable backsheet, an absorbent core (62) having a core wrap disposed between the topsheet and the backsheet, an optional acquisition layer (64), and a landing zone (44); - wherein the backsheet comprises a liquid-impermeable film (60) and a nonwoven outer cover (42), wherein the landing zone (44) comprises a discrete nonwoven material bonded to the nonwoven outer cover (42); - wherein the nonwoven-nonwoven adhesive bonds are selected from one or more of the following: (i) The bonding area between the landing zone and the backsheet; (ii) bonding portion (76) between the top sheet and the acquisition layer; (iii) an acquisition layer and core wrap bond (78); (iv) Bonding of topsheet to core wrap.

2. An absorbent article according to claim 1, wherein when the absorbent article is a pant diaper (20), the adhesive nonwoven-nonwoven bond comprises at least one bond according to i), ii), iii) and iv).

3. The absorbent article according to claim 1, wherein when the absorbent article is a taped diaper (20'), the nonwoven-to-nonwoven adhesive bonds comprise at least a land zone and backsheet bond.

4. The absorbent article of any one of claims 1-3, wherein the adhesive comprises a propylene-based polymer or a blend of propylene-based polymers.

5. The absorbent article of claim 4, wherein the adhesive comprises at least 25 weight percent of the propylene-based polymer or blend of propylene-based polymers.

6. The absorbent article of claim 5, wherein at least one of the propylene-based polymers has a melting enthalpy of at least 20 J / g.

7. The absorbent article according to claim 6, wherein at least one of the propylene-based polymers has a melting enthalpy of 20 J / g to 50 J / g.

8. The absorbent article of any one of claims 1-3, wherein the adhesive comprises, by weight of the adhesive: - 15% to 45% of a single site catalyzed and propylene based first polymer having a Mw of 30,000 to 75,000; and - 2% to 15% of a propylene-based second polymer having a Mw of 100,000 to 400,000; The weight average molecular weight Mw is determined according to ISO 16014 standard.

9. The absorbent article of claim 8, wherein the first polymer comprises: - a first metallocene-catalyzed propylene-ethylene copolymer having a melting enthalpy below 20 J / g; - a second metallocene-catalyzed propylene-ethylene copolymer having a melting enthalpy higher than 20 J / g.

10. The absorbent article according to any one of claims 1 to 3, wherein the adhesive has a storage modulus G' of at least 3 MPa, wherein the storage modulus G' is measured at 37°C according to the Oscillatory Rheology Test Method.

11. The absorbent article of claim 10, wherein the adhesive has a G' of 7.5 MPa to 50 MPa, wherein the G' is measured at 37°C according to the Oscillatory Rheology Test Method.

12. The absorbent article according to any one of claims 1 to 3, wherein the adhesive is present at 0.5 g / m 2 Up to 30g / m 2 An average basis weight of is applied in the adhesive bond.

13. The absorbent article according to any one of claims 1 to 3, wherein the adhesive is present at 1.5 g / m 2 Up to 25g / m 2 An average basis weight of is applied in the adhesive bond.

14. The absorbent article according to any one of claims 1 to 3, wherein the adhesive has a strength of at least 22 MJ / m 3 toughness, and a yield stress of 1.0MPa to 20MPa.

15. The absorbent article according to claim 14, wherein the adhesive has a strength of at most 60 MJ / m 3 toughness.

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