Elastomeric laminate with control layer and methods thereof

Abstract

To produce an absorbent article incorporating elastomeric laminates that may be formed by stretching and joining an elastic strand with either or both of first and second substrates using an adhesive.SOLUTION: Elastic strands 318 are provided from a wound supply of elastic strands. The wound supply of elastic strands comprises a control layer 352 having a solubility parameter within the range of about 15.5 MPa1 / 2 to about 16.5 MPa1 / 2, and a number average molecular weight within the range of about 0.6 kg / mol to about 1.5 kg / mol.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to absorbent articles having an elastomeric laminate, and more particularly to adhesives, control layers, and elastic strands of the elastomeric laminate.

Background Art

[0002] Along an assembly line, various types of articles, such as diapers and other absorbent articles, can be assembled by adding components to a continuous web of advancing material and / or otherwise processing the continuous web of material. For example, in some processes, a continuous web of advancing material is combined with another continuous web of advancing material. In other examples, individual components made from a continuous web of advancing material are combined with the continuous web of advancing material and then these are combined with other continuous webs of advancing material. In some examples, individual components made from the advancing web(s) are combined with other individual components made from other advancing webs. The webs and components of materials used to manufacture diapers may include a backsheet, a topsheet, leg cuffs, a waistband, an absorbent core component, front and / or rear ears, fastening components, and various types of elastic webs and components such as leg elastics, barrier leg cuff elastics, stretch side panels, and waist elastics. Once the desired component parts are assembled, the advancing webs and component parts are subjected to a final knife cut to separate the web into individual diapers or other absorbent articles.

[0003] Some absorbent articles have components that include an elastomeric laminate. Such an elastomeric laminate can include an elastic material bonded to one or more nonwoven fabrics. The elastic material can include an elastic film and / or elastic strands. In some laminates, when a plurality of strands are in a stretched state, the plurality of elastic strands are bonded to form a nonwoven fabric, such that when the elastic strands relax, the nonwoven fabric forms pleats between the positions where it is joined to the elastic strands, thereby forming a waveform. The resulting elastomeric laminate is stretchable to an extent that the elastic strands can be stretched by the waveform.

[0004] In some assembly processes, the stretched elastic strands can be advanced in the machine direction and adhered between two advancing substrates, with the stretched elastic strands being spaced apart from each other in the cross direction. Some assembly processes are also configured using a number of elastic strands that are very closely spaced from each other in the cross direction. In some configurations, the close cross-directional spacing between the elastic strands can be achieved by pulling the elastic strands from a coil laminated in the cross direction on a beam. For example, various fiber manufacturers can utilize beam elastics and related handling devices such as those available from Karl Mayer Corporation.

[0005] However, problems can occur in the manufacturing process when using elastic strands laminated on a beam. For example, the elastic strands on the beam are prone to blocking when being pulled from the beam due to cross-linking between the strands caused by the beam being highly compressed over a significant storage life. To prevent blocking from occurring in the elastic strands, the elastic strands can be treated with silicone oil or other types of spin finishes. Applying a spin finish to the beam can reduce the likelihood of blocking, but the spin finish can have an undesirable impact on the manufacturing process. For example, when the elastic strands are formed into an elastomeric laminate and an adhesive is used to bond the strands to the nonwoven layer, the spin finish can have an adverse effect on the effectiveness of the adhesive. To achieve the desired level of adhesion, a relatively large amount of adhesive may be required. Using a large amount of adhesive is undesirable as it increases the cost of materials and also results in a hard laminate that does not have the desired appearance or performance for incorporation into an absorbent article. SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0006] As a result, it would be beneficial to provide a method and apparatus for producing an elastomeric laminate from elastic strands that utilize an anti-blocking agent and are readily adherable to a nonwoven layer. Further, it would be beneficial to form a disposable absorbent article incorporating the elastomeric laminate. MEANS FOR SOLVING THE PROBLEM

[0007] In a first aspect, a disposable absorbent article in the form of a diaper or absorbent pants may comprise a liquid-permeable topsheet, a liquid-impermeable backsheet, and an absorbent core disposed between the topsheet and the backsheet. The disposable absorbent article may comprise an elastomeric laminate. The elastomeric laminate may include a plurality of laterally spaced elastic strands joined to a nonwoven web material by an adhesive. The elastic strands may include a strand polymer (e.g., segmented polyurethane), and the strand polymer may have a solubility parameter in the range of about 18 MPa 1 / 2 to about 18.5 MPa 1 / 2 The adhesive may include an adhesive polymer, and the adhesive polymer may have a solubility parameter in the range of about 16 MPa 1 / 2 to about 17.5 MPa 1 / 2 The elastic strands may be supplied from a roll supply of the elastic strands. The roll supply of the elastic strands may include a control layer having a solubility parameter in the range of about 15.5 MPa 1 / 2 to about 16.5 MPa 1 / 2 and a number average molecular weight in the range of about 0.6 kg / mol to about 1.5 kg / mol.

[0008] In another aspect, a disposable absorbent article in the form of a diaper or absorbent pants may comprise an elastomeric laminate. The elastomeric laminate includes a plurality of laterally spaced elastic strands joined to at least a first layer of nonwoven web material by an adhesive. The elastic strands include a first block copolymer of the spandex type. The block copolymer may include a rubber block and a rigid block. The rubber block may be selected from the group consisting of polyethers, polyesters, and combinations thereof. The adhesive may include an adhesive polymer, and the adhesive polymer may include a second block copolymer of the styrenic type. In some implementations, the adhesive may include a tackifier. The second block copolymer may include a rubber block, and the rubber block may be selected from the group consisting of polyisoprene, polybutadiene, polyisoprene-co-butadiene, and hydrogenated variants thereof. The control layer may be at least partially dispersed from the elastic strands into the adhesive.

[0009] In yet another aspect, a disposable absorbent article in the form of a diaper or absorbent pants may comprise an elastomeric laminate. The elastomeric laminate may include a plurality of laterally spaced elastic strands joined to at least a first layer of nonwoven web material by an adhesive. The elastic strands may include a first block copolymer of the spandex type. The block copolymer may include a rubber block and a rigid block, and the rubber block may be selected from the group consisting of polyethers, polyesters, and combinations thereof. The adhesive may include an adhesive polymer, and the adhesive polymer may include a second block copolymer of the styrenic type. The second block copolymer may include a rubber block selected from the group consisting of polyisoprene, polybutadiene, polyisoprene-co-butadiene, and hydrogenated variants thereof. The elastomeric laminate may include soap.

[0010] In another aspect, a process for making an elastomeric laminate may include unwinding an elastomeric strand coated with a control layer. The control layer may include mineral oil. The process may further include bonding elastomeric strands between a first substrate layer and a second substrate layer to form an elastomeric laminate. The elastomeric strands may have an average strand spacing of from about 0.25 mm to about 4 mm, and the average Dtex of the elastomeric strands may be from about 10 to about 500.

[0011] In yet another aspect, a method for assembling an elastomeric laminate may include providing a first substrate and a second substrate. The method may further include advancing an elastic strand in a machine direction. The elastic strands may be separated from each other in a transverse direction. The method may further include applying an adhesive to at least one of the elastic strand, the first substrate, and the second substrate, and combining the elastic strand with the first substrate and the second substrate to form an elastomeric laminate. The method may further include dispersing a control layer from the elastic strand into the adhesive. The control layer may include mineral oil.

Brief Description of the Drawings

[0012]

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DETAILED DESCRIPTION OF THE INVENTION

[0013] The following glossary may be useful in understanding the present disclosure. As used herein, the term "absorbent article" is used to refer to a consumer product whose main function is to absorb and retain dirt and excrement. As used herein, "diaper" is used to refer to an absorbent article that is typically worn around the lower torso by infants and people with incontinence. As used herein, the term "disposable" is used to describe an absorbent article that is not generally intended to be washed or otherwise recycled or reused as an absorbent article (e.g., these are intended to be discarded after a single use and may be configured to be recycled, composted, or disposed of in another environmentally compatible manner).

[0014] "Elastic", "elastomer", or "elastomeric" refers to a material exhibiting elastic properties, which includes any material that, when a force is applied to its relaxed initial length, can stretch or elongate to an elongation length exceeding 10% of its initial length and, after the applied force is released, substantially returns to its initial length.

[0015] As used herein, the term "joined" encompasses configurations in which one element is directly fixed to another element by attaching the one element directly to the other element, as well as configurations in which one element is attached to an intermediate member(s) and the intermediate member is attached to another element such that the one element is indirectly fixed to the other element.

[0016] The term "longitudinal direction" means a direction that extends substantially perpendicular from the waist edge of the absorbent article to the opposite waist edge in the longitudinal direction, or from the waist edge to the bottom of the crotch, i.e., the fold line of the article folded in half, when the absorbent article is in a non-contracted state laid flat. Directions within 45 degrees of the longitudinal direction are considered to be the "longitudinal direction". The term "lateral direction" refers to a direction that extends from the side edge extending in the longitudinal direction of the article to the opposite side edge extending in the longitudinal direction and is generally perpendicular to the longitudinal direction. Directions within 45 degrees of the lateral direction are considered to be the "lateral direction".

[0017] In this specification, the term "base material" is mainly two-dimensional (i.e., within the XY plane), and is used to describe a material whose thickness (Z direction) is relatively small (i.e., 1 / 10 or less) compared to its length (X direction) and width (Y direction). Non-limiting examples of the base material include webs, layers (one or more), or fibrous materials, nonwovens, polymer films, or films and foils such as metal foils. These materials may be used alone or may include two or more layers laminated together. For this reason, a web is a base material.

[0018] In this specification, the term "nonwoven fabric" refers to a material made from continuous (long) filaments (fibers) and / or discontinuous (short) filaments (fibers) by processes such as spunbond, meltblown, and carding. Nonwoven fabrics do not have a woven or knitted filament pattern.

[0019] In this specification, the term "machine direction" (MD) is used to refer to the direction of the flow of the material passing through the process. In addition, the relative arrangement and movement of the material can be described as flowing in the machine direction from the upstream to the downstream of the process through a certain process.

[0020] In this specification, the term "cross direction" (CD) is used to refer to a direction that is substantially perpendicular to the machine direction.

[0021] The term "tape diaper" (also referred to as "open diaper") refers to a disposable absorbent article having an initial front waist region and an initial rear waist region that are not fastened, pre-fastened, or joined to each other during packaging before being applied to the wearer. The tape diaper may be folded around the lateral center line with the inner surfaces of one waist region in contact with the inner surfaces of the opposite waist region without fastening or joining the waist regions together. Examples of tape diapers with various suitable configurations are disclosed in U.S. Patent Nos. 5,167,897; 5,360,420; 5,599,335; 5,643,588; 5,674,216; 5,702,551; 5,968,025; 6,107,537; 6,118,041; 6,153,209; 6,410,129; 6,426,444; 6,586,652; 6,627,787; 6,617,016; 6,825,393; and 6,861,571, as well as U.S. Patent Publications Nos. 2013 / 0072887(A1); 2013 / 0211356(A1); and 2013 / 0306226(A1).

[0022] As used herein, the term "pants" (also referred to as "training pants", "pre-closed diaper", "diaper pants", "pant-type diaper", and "pull-on diaper") refers to a disposable absorbent article designed for infant or adult wearers and having a continuous waist opening at the outer periphery and a continuous leg opening at the outer periphery. The pants may be configured to have a continuous or closed waist opening and at least one continuous closed leg opening prior to the article being applied to the wearer. The pants may be preformed or pre-fastened using various techniques including, but not limited to, using any re-fastenable closure member and / or permanent closure member (e.g., seams, thermal bonds, pressure bonds, adhesives, cohesive bonds, mechanical fasteners, etc.) to join parts of the article to each other. The pants may be preformed at any location along the outer periphery of the article within the waist region (e.g., side fastening or sewing, front waist fastening or sewing, back waist fastening or sewing). Examples of diaper pants of various configurations are disclosed in U.S. Pat. Nos. 4,940,464, 5,092,861, 5,246,433, 5,569,234, 5,897,545, 5,957,908, 6,120,487, 6,120,489, 7,569,039, and U.S. Patent Application Publication Nos. 2003 / 0233082 (A1), 2005 / 0107764 (A1), 2012 / 0061016 (A1), 2012 / 0061015 (A1), 2013 / 0255861 (A1), 2013 / 0255862 (A1), 2013 / 0255863 (A1), 2013 / 0255864 (A1), and 2013 / 0255865 (A1).

[0023] "Decitex", also known as "Dtex", is a measurement used in the textile industry for measuring yarns or filaments. 1 decitex = 1 gram per 10,000 meters. In other words, if 10,000 linear meters of relaxed yarn or filament has a weight of 500 grams, then that yarn or filament has 500 decitex.

[0024] The present disclosure relates to disposable absorbent articles, particularly disposable absorbent articles incorporating an elastomeric laminate, and a process for making the elastomeric laminate. The disposable absorbent article according to the present disclosure can be in the form of a diaper or absorbent pants and can include a liquid-permeable topsheet, a liquid-impermeable backsheet, and an absorbent core disposed between the topsheet and the backsheet. The disposable absorbent article can also include an elastomeric laminate including a plurality of laterally spaced elastic strands joined to a nonwoven web material by an adhesive. The elastic strands can include, for example, a strand polymer having a solubility parameter in the range of about 18 MPa 1 / 2 to about 18.5 MPa. 1 / 2 The adhesive can include, for example, an adhesive polymer (such as a styrene block copolymer or a polyolefin-based polymer, or a blend thereof) having a solubility parameter in the range of about 16 MPa 1 / 2 to about 17.5 MPa. 1 / 2 The adhesive of the present disclosure may or may not include a tackifier. Furthermore, the adhesive of the present disclosure can include less than 20% tackifier, less than 15% tackifier, less than 10%, or less than 5% tackifier. The elastic strands can be supplied from a wound supply of the elastic strands, such as a beam, spool, or other source. The wound supply of the elastic strands can include, for example, a control layer having a solubility parameter in the range of about 15.5 MPa 1 / 2 to about 16.5 MPa 1 / 2 and a number average molecular weight in the range of about 0.6 kg / mol to about 1.5 kg / mol. For additional information regarding the determination of solubility parameters according to the present disclosure, refer to "CRC Handbook of Chemistry and Physics, 97th Edition", CRC Press, Taylor & Francis Group, 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742. For additional information regarding the determination of number average molecular weight (using polystyrene as the calibration standard and based on a refractive index (RI) detector) according to the present disclosure, see "Introduction to Polymers, 2 nd nd Edition", R.J. Young and P.A. Lovell, pages 211 - 221.

[0025] The beam can include from about 40 to about 1000 elastic strands, or from about 100 to about 750 elastic strands, or from about 200 to about 600 elastic strands, or from about 300 to about 500 elastic strands. The present disclosure emphasizes the advantages of using a control layer with a beam that includes many fine (less than about 500 dtex) elastic strands, but it should be understood that it may also be desirable to use a control layer on a spool that can include a single elastic strand. Further, it may be desirable to use a control layer on elastic strands of traditional size (greater than about 500 dtex).

[0026] Furthermore, the elastomeric laminate according to the present disclosure can include a plurality of laterally spaced elastic strands that include spandex - based polymers. Commercially available spandex strands are also known as Lycra, Creora, Roica, or Dorlastan. Spandex polymers are sometimes referred to as elastane, segmented polyurethane copolymers, or segmented polyurea copolymers. Spandex polymers contain rubber blocks and rigid blocks. These blocks are connected by urethane or urea chemical bonds. Typical rubber blocks include polyethers such as polytetramethylene oxide or polyesters such as polycaprolactone. Rigid blocks can include diisocyanates such as diphenylmethane 4,4'-diisocyanate (MDI) and toluene-2,4-diisocyanate (TDI). These diisocyanates can optionally be bonded together using diols such as butanediol or diamines such as hydrazine or ethylenediamine. It is understood that various rubber blocks, rigid blocks, and coupling agents can be contemplated for use. For example, rubber block polymers can include polyesters such as polyethylene adipate, polypropylene adipate, and polybutylene adipate, poly-1,5-pentanediol, 1,6-hexanediol, or 1,10-decanediol, or polyethers such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Similarly, rigid blocks can contain diphenylmethane 4,4'-diisocyanate (MDI), toluene-2,4-diisocyanate (TDI), hexamethylene diisocyanate (HDI), methylene dicyclohexyl diisocyanate (hydrogenated MDI (HMDI)) or isophorone diisocyanate (IPDI). Similarly, any coupling agent for the rigid block can include diamines (such as hydrazine and ethylenediamine) or diols (such as butanediol, 1,5-pentanediol, 1,6-hexanediol).

[0027] The adhesive of the elastomer laminate may include an adhesive polymer containing a styrenic block copolymer. The block copolymer may include a rubber block selected from the group consisting of polyisoprene, polybutadiene, polyisoprene-co-butadiene, and hydrogenated variants thereof. In some embodiments, the elastomer laminate may also include soap.

[0028] Furthermore, the adhesive polymer of the present disclosure can be a styrene block copolymer, a polyolefin-based polymer, or a blend thereof. The styrene block copolymers of the present disclosure can include styrene-butadiene (SB), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-isoprene (SI), styrene-isoprene-butadiene-styrene (SIBS), styrene-ethylene-butylene-styrene (SEBS), styrene-ethylene-butylene (SEB), styrene-ethylene-propylene-styrene (SEPS), and styrene-ethylene-propylene (SEP), and styrene-ethylene-ethylene-propylene-styrene (SEEPS or hydrogenated SIBS). The styrene block copolymers of the present disclosure can have a general structure of A-B-A, or a mixture of A-B and A-B-A, and at the same time, the polymer terminal block A is styrene, while the polymer intermediate block B can be derived from isoprene, butadiene, or isobutylene, or a mixture thereof that can be partially or substantially hydrogenated. Furthermore, the copolymer can be linear or branched. In particular, a styrene content of more than 40% in the styrene block copolymer can reinforce creep resistance, and at the same time, a melt flow index of more than 33 can enable a desirable viscosity. The polyolefin-based polymers of the present disclosure can be propylene homopolymers and propylene-based polymers that are copolymers with one or more other comonomers (such as ethylene, butene, pentene, octene, etc.). The propylene-based polymers can be entirely olefinic, that is, they do not contain any functional groups. The propylene-based polymers can contain more than 75% by weight of propylene, or even more than 80% by weight of propylene. Furthermore, the propylene-based polymers can contain 10-20 mol% or 13-16 mol% of comonomers. The propylene-based polymers can have a polydispersity (Mw / Mn) of less than about 5, less than about 3, or even less than about 2. Useful propylene-based polymers can have a density of less than about 0.90, less than about 0.89, or even less than about 0.88. Examples of useful propylene-based polymers include propylene-based polymers produced by single-site (e.g., metallocene) catalysts.Furthermore, the polyolefin-based polymer can be a copolymer of ethylene and a C3-Cα-olefin prepared in the presence of a metallocene as a catalyst. 20 It can be a copolymer of ethylene and a C3-Cα-olefin.

[0029] According to the present disclosure, a process for producing an elastomer laminate can include unwinding an elastomer strand coated with a control layer. The control layer can include, for example, mineral oil, paraffinic mineral oil, white mineral oil, synthetic oil, polyisoprene, and / or polybutadiene. The process can include bonding the elastomer strand between a first substrate layer and a second substrate layer to form an elastomer laminate, and the elastomer strand can have an average strand spacing of, for example, about 0.25 mm to about 4 mm, or about 0.25 mm to about 3 mm, or about 0.5 mm to about 3 mm, or about 0.25 mm to about 2 mm, or about 0.5 mm to about 2 mm. Further, the average Dtex of the elastomer strand can range from about 10 to about 500, or about 10 to about 400, or about 10 to about 300. The relative amount of the control layer utilized on the elastomer strand can vary, but in some embodiments, the control layer is less than about 5 wt%, or less than 3 wt%, or less than 2 wt% of the elastomer strand.

[0030] Furthermore, according to the present disclosure, a method for assembling an elastomer laminate can include providing a first substrate and a second substrate, and advancing an elastic strand in the machine direction. The elastic strands can be separated from each other in the cross direction. The method can also include applying an adhesive to at least one of the elastic strand, the first substrate, and the second substrate, and combining the elastic strand with the first substrate and the second substrate to form an elastomer laminate. The method can also include dispersing a control layer containing mineral oil from the elastic strand into the adhesive.

[0031] As described above, the elastomeric laminate produced according to the processes and apparatuses discussed herein can be used to construct various types of components used in the manufacture of different types of absorbent articles such as diaper pants and tape-type diapers. To help provide further context for the discussion following the process embodiments, an overview of a diaper form absorbent article including components such as elastomeric laminates that can be produced using the methods and apparatuses disclosed herein is provided below.

[0032] Figures 1A, 1B, and 2 show an example of a diaper pant 100 that may include components constructed from an elastomeric laminate assembled according to the apparatuses and methods disclosed herein. Specifically, FIGS. 1A and 1B show perspective views of the diaper pant 100 in a pre-fastened form, and FIG. 2 shows a plan view of the diaper pant 100 with the portion of the diaper facing away from the wearer oriented towards the viewer. The diaper pant 100 includes a chassis 102 and an annular elastic belt 104. As will be discussed in more detail below, the first elastic belt 106 and the second elastic belt 108 can be joined together to form the annular elastic belt 104.

[0033] Continuing to refer to FIG. 2, the diaper pants 100 and the chassis 102 each include a first waist region 116, a second waist region 118, and a crotch region 119 disposed intermediate the first and second waist regions. The first waist region 116 may be configured as a front waist region, and the second waist region 118 may be configured as a rear waist region. The diaper 100 may also include a front waist edge 121 that extends horizontally in the front waist region 116 and a rear waist edge 122 that faces longitudinally and extends horizontally in the rear waist region 118. To provide a reference system for this discussion, the diaper 100 and the chassis 102 of FIG. 2 are shown as having a longitudinal axis 124 and a transverse axis 126. In some embodiments, the longitudinal axis 124 may extend through the front waist edge 121 and the rear waist edge 122. And the transverse axis 126 may extend through the first longitudinal or right edge 128 of the chassis 102 and through the midpoint of the second longitudinal or left edge 130.

[0034] As shown in FIGS. 1A, 1B, and 2, the diaper pants 100 may include an inner, body-facing surface 132 and an outer, clothing-facing surface 134. The chassis 102 may include a backsheet 136 and a topsheet 138. The chassis 102 may also include an absorbent assembly 140 that includes an absorbent core 142 disposed between a portion of the topsheet 138 and the backsheet 136. As will be described in more detail below, the diaper 100 may also include other features such as leg elastic members and / or leg cuffs to enhance the fit around the wearer's legs.

[0035] As shown in FIG. 2, the peripheral portion of the chassis 102 may be defined by a first longitudinally extending side edge portion 128, a second longitudinally extending side edge portion 130, a first laterally extending edge portion 144 disposed within the first waist region 116, and a second laterally extending edge portion 146 disposed within the second waist region 118. Both side edge portions 128 and 130 extend longitudinally between the first edge portion 144 and the second edge portion 146. As shown in FIG. 2, the laterally extending edge portions 144 and 146 may be located longitudinally inward from the front side waist edge portion 121 that extends laterally in the front side waist region 116 and from the rear side waist edge portion 122 that extends laterally in the rear side waist region 118. When the diaper pants 100 are worn on the lower torso of the wearer, the front side waist edge portion 121 and the rear side waist edge portion 122 may surround the portion of the wearer's waist. At the same time, the side edge portions 128 and 130 may surround at least a portion of the wearer's legs. Also, the crotch region 119 may generally be positioned between the legs of the wearer, and the absorbent core 142 extends from the front side waist region 116 through the crotch region 119 to the rear side waist region 118.

[0036] As described above, the diaper pants 100 may include a backsheet 136. The backsheet 136 may also define the outer surface 134 of the chassis 102. The backsheet 136 may also include a woven or non-woven material, a polymeric film such as a polyethylene or polypropylene thermoplastic film, and / or a multilayer or composite material including a film and a non-woven material. The backsheet may also include an elastomeric film. The exemplary backsheet 136 may be a polyethylene film having a thickness of about 0.012 mm (0.5 mil) to about 0.051 mm (2.0 mil). Further, the backsheet 136 can prevent the excrement from passing through the backsheet 136 while allowing the vapor to escape from the absorbent core (i.e., the backsheet is breathable).

[0037] Also, as described above, the diaper pants 100 may include a topsheet 138. The topsheet 138 may also define all or a part of the inner surface 132 of the chassis 102. The topsheet 138 is liquid permeable, and liquids (e.g., menstrual blood, urine and / or liquid feces) may penetrate through its thickness. The topsheet 138 may be manufactured from a wide range of materials such as woven and non-woven materials, perforated or hydroformed thermoplastic films, perforated non-wovens, porous foams, reticulated foams, reticulated thermoplastic films; and thermoplastic scrims. The woven or non-woven material may be manufactured from a wide range of materials such as natural fibers such as wood or cotton fibers, synthetic fibers such as polyester, polypropylene or polyethylene fibers, or combinations thereof. If the topsheet 138 includes fibers, the fibers may be treated by a spunbond method, a carding method, a wet method, a meltblown method, a hydroentanglement method, or another method known in the art. The topsheet 138 may be selected from a bulky non-woven topsheet, a perforated film topsheet, and a perforated non-woven topsheet. Exemplary perforated films may include those described in U.S. Patent Nos. 5,628,097, 5,916,661, 6,545,197, and 6,107,539.

[0038] As described above, the diaper pants 100 may also include an absorbent assembly 140 joined to the chassis 102. As shown in FIG. 2, the absorbent assembly 140 may have a front edge 148 that extends horizontally within the front waist region 116, and may have a rear edge 150 that extends longitudinally opposite and horizontally within the rear waist region 118. The absorbent assembly may have a right side edge 152 that extends longitudinally, and may have a left side edge 154 that is on the opposite side horizontally and extends longitudinally. Both side edges 152 and 154 of the absorbent assembly may extend longitudinally between the front edge 148 and the rear edge 150. The absorbent assembly 140 may additionally include one or more absorbent cores 142 or absorbent core layers. The absorbent core 142 may be at least partially disposed between the top sheet 138 and the back sheet 136, and may be formed in various sizes and shapes that are compatible with the diaper. Exemplary absorbent structures for use as the absorbent core of the present disclosure are described in U.S. Pat. Nos. 4,610,678, 4,673,402, 4,888,231, and 4,834,735.

[0039] Some absorbent core embodiments may include a fluid storage core containing a reduced amount of cellulosic airfelt material. For example, such a core may include less than about 40%, less than 30%, less than 20%, less than 10%, less than 5%, or even less than about 1% of cellulosic airfelt material. Such cores may mainly include an absorbent gel material in an amount of at least about 60%, 70%, 80%, 85%, 90%, 95%, or even about 100%, in which case the remainder of the core includes a microfiber adhesive (where applicable). Such cores, microfiber adhesives, and absorbent gel materials are described in U.S. Pat. Nos. 5,599,335, 5,562,646, 5,669,894, and 6,790,798, and U.S. Patent Publications 2004 / 0158212(A1) and 2004 / 0097895(A1).

[0040] As described above, the diaper 100 may also include an elastic leg cuff 156. The leg cuff 156 can be a leg band, side flap, barrier cuff, elastic cuff or gasketting cuff and may in some cases be referred to as such. The elastic leg cuff 156 may be configured in various ways to help reduce leakage of body exudates in the leg region. Exemplary leg cuffs 156 can include those described in U.S. Pat. Nos. 3,860,003; 4,909,803; 4,695,278; 4,795,454; 4,704,115; 4,909,803; and U.S. Patent Application Publication No. 2009 / 0312730 (A1).

[0041] The diaper pants are manufactured with an annular elastic belt 104 and, before being applied to the wearer, the front waist region 116 and the rear waist region 118 may be connected to each other and provided to the consumer in a packaged configuration. Thus, the diaper pants may have a continuous outer peripheral waist opening 110 and a continuous outer peripheral leg opening 112 as shown in FIGS. 1A and 1B. This annular elastic belt can be formed by joining a first elastic belt to a second elastic belt using a permanent side seam or using a releasable and reclosable fastening system disposed on or adjacent to the sides of the belt that face each other in the transverse direction of the belt.

[0042] The annular elastic belt 104 may be defined by a first elastic belt 106 connected to a second elastic belt 108. As shown in FIG. 2, the first elastic belt 106 extends between a first longitudinal side edge 111a and a second longitudinal side edge 111b, defining first and second opposing end regions 106a, 106b and a central region 106c. The second elastic belt 108 extends between a first longitudinal side edge 113a and a second longitudinal side edge 113b, defining first and second opposing end regions 108a, 108b and a central region 108c. The distance between the first longitudinal side edge 111a and the second longitudinal side edge 111b defines the pitch length PL of the first elastic belt 106, and the distance between the first longitudinal side edge 113a and the second longitudinal side edge 113b defines the pitch length PL of the second elastic belt 108. The central region 106c of the first elastic belt may be connected to a first waist region 116 of the chassis 102, and the central region 108c of the second elastic belt 108 may be connected to a second waist region 118 of the chassis 102. As shown in FIGS. 1A and 1B, the first end region 106a of the first elastic belt 106 may be connected to the first end region 108a of the second elastic belt 108 at a first side seam 178, and the second end region 106b of the first elastic belt 106 may be connected to the second end region 108b of the second elastic belt 108 at a second side seam 180 to define the annular elastic belt 104 and the waist opening 110 and the leg opening 112.

[0043] As shown in FIGS. 2, 3A, and 3B, the first elastic belt 106 also defines a laterally extending outer edge 107a and a laterally extending inner edge 107b, and the second elastic belt 108 defines a laterally extending outer edge 109a and a laterally extending inner edge 109b. In this way, the outer peripheral edge 112a of one leg opening can be defined by the laterally extending inner edge 107b of the first elastic belt 106, the laterally extending inner edge 109b of the second elastic belt 108, and a portion of the first longitudinal or right side edge 128 of the chassis 102. Further, the outer peripheral edge 112b of the other leg opening can be defined by the laterally extending inner edge 107b, the laterally extending inner edge 109b, and a portion of the second longitudinal or left side edge 130 of the chassis 102. The laterally extending outer edges 107a, 109a can also define the front waist edge 121 and the laterally extending rear waist edge 122 of the diaper pants 100. The first elastic belt and the second elastic belt may each also include an outer layer 162 facing the outer clothing and an inner layer 164 facing the wearer. It will be understood that the first elastic belt 106 and the second elastic belt 108 may include the same material and / or have the same structure. In some embodiments, the first elastic belt 106 and the second elastic belt may include different materials and / or have different structures. It will also be understood that the first elastic belt 106 and the second elastic belt 108 may be made of a variety of materials. For example, the first belt and the second belt may be made of plastic film, perforated plastic film, natural materials (e.g., wood fibers or cotton fibers), synthetic fibers (e.g., polyolefin, polyamide, polyester, polyethylene or polypropylene fibers), or a woven or non-woven web of a combination of natural fibers and / or synthetic fibers, or a coated woven or non-woven web, etc., from a wide range of materials. In some embodiments, the first and second elastic belts include a non-woven web of synthetic fibers and may include a stretch non-woven. In other embodiments, the first and second elastic belts include an inner hydrophobic and non-stretch non-woven material and an outer hydrophobic and non-stretch non-woven material.

[0044] Further, the first and second elastic belts 106, 108 may each further include a belt elastic material interposed between an outer substrate layer 162 and an inner substrate layer 164. The belt elastic material may include one or more elastic elements extending along the length of the elastic belt, such as strands, ribbons, films, or panels. As shown in FIGS. 2, 3A, and 3B, the belt elastic material may include a plurality of elastic strands 168, which may be referred to herein as an outer waist elastic body 170 and an inner waist elastic body 172. The elastic strands 168 (e.g., the outer waist elastic member 170) may extend continuously laterally between a first opposing end region 106a and a second end region 106b of the first elastic belt 106, and between a first opposing end region 108a and a second end region 108b of the second elastic belt 108. In some embodiments, some of the elastic strands 168 (e.g., the inner waist elastic member 172) may be configured to have discontinuities, for example, within a region where the first and second elastic belts 106, 108 overlap the absorbent assembly 140. In some embodiments, the elastic strands 168 may be longitudinally disposed at regular intervals. In other embodiments, the elastic strands 168 may be disposed at different intervals longitudinally. The belt elastic material in the stretched state may be interposed and joined between a non-shrinking outer layer and a non-shrinking inner layer. When the belt elastic material is relaxed, the belt elastic material returns to the non-stretched state and causes the outer and inner layers to contract. The belt elastic material may provide a desired change in the contraction force within the region of the annular elastic belt. It should be understood that the chassis 102 and the elastic belts 106, 108 may be configured in a manner different from that shown in FIG. 2. The belt elastic material may be continuously or intermittently joined to the outer layer and / or the inner layer along an interface between the belt elastic material and the outer layer and / or the inner layer.

[0045] In some configurations, the first elastic belt 106 and / or the second elastic belt 108 may define a curved contour. For example, the inner lateral edges 107b, 109b of the first and / or second elastic belts 106, 108 may include non-linear or curved portions at the first and second opposing end regions. Such a curved contour can help define a desired shape for the leg opening 112, such as a relatively rounded leg opening. The elastic belts 106, 108 not only have a curved contour but may also include elastic strands 168, 172 that extend along a non-linear or curved path that may coincide with the curved contour of the inner lateral edges 107b, 109b.

[0046] The devices and methods according to the present disclosure may be utilized to manufacture elastomeric laminates that can be used to construct various components of a diaper, such as elastic belts, leg cuffs, etc. For example, FIGS. 4-8 show various schematic views of a processing apparatus 300 adapted to manufacture an elastomeric laminate 302. As described in more detail below, the processing apparatus 300 shown in FIGS. 4-8 operates to advance a continuous length of elastic material 304, a continuous length of a first substrate 306, and a continuous length of a second substrate 308 along the machine direction MD. In some configurations, it should be understood that the first substrate 306 and the second substrate 308 herein may be defined by two separate substrates or may be defined by folded portions of a single substrate. The apparatus 300 may stretch the elastic material 304 and bond the stretched elastic material 304 to the first and second substrates 306, 308 to manufacture the elastomeric laminate 302. The elastic material 304 may be supplied from a rotating beam around which elastic strands are wound or from another type of wound supply of elastic strands. During operation, the elastic material may advance in the machine direction from the rotating beam.

[0047] The elastomeric laminate 302 can be used to construct various types of diaper components such as belts, ear panels, side panels, lateral barriers, top sheets, back sheets, cuffs, waistbands, waist caps, and / or chassis. For example, the elastomeric laminate 302 can be used as a continuous length of elastomeric belt material that can be processed into the first and second elastic belts 106, 108 described above in connection with FIGS. 1-3B. Thus, the elastic material 304 can correspond to a belt elastic material 168 interposed between an outer layer 162 and an inner layer 164 that can subsequently correspond to either the first and / or second substrates 306, 308. In other examples, the elastomeric laminate can be used to construct the waistband and / or side panels of a tape-type diaper structure. In yet other embodiments, the elastomeric laminate can be used to construct various types of leg cuffs and / or top sheet structures. When the elastomeric laminate 302 forms at least a portion of at least one of the group consisting of belts, chassis, side panels, top sheets, back sheets, and ear panels, and combinations thereof, the plurality of elastomers 318 of the elastomeric laminate 302 may include from about 40 to about 1000 elastic strands. Also, when the elastomeric laminate 302 forms at least a portion of at least one of the group consisting of waistbands, waist caps, inner leg cuffs, outer leg cuffs, and combinations thereof, the first plurality of elastomers 316 of the elastomeric laminate 302 may include from about 10 to about 400 elastic strands. Finally, "plurality of elastomers" is a contextual term, and the specific properties, arrangements, attributes, features, configurations, etc. of these elastomers are referenced to define what the particular "plurality of elastomers" is.

[0048] As shown in FIGS. 4 to 5, the processing apparatus 300 for manufacturing the elastomer laminate 302 may include a first metering device 310 and a second metering device 312. The first metering device may be configured as a beam 316 around which a plurality of elastic strands 318 are wound. FIG. 6 shows an example of an empty beam 316 including two side plates 317a, 317b that can be connected to both ends of the mandrel core 319, and the elastic strands can be wound around the mandrel core 319. It should be understood that according to the methods and apparatuses herein, beams of various sizes and technical specifications can be utilized, such as beams available from, for example, ALUCOLOR Textilmaschinen, GmbH. During operation, the plurality of elastic strands 318 advance in the machine direction MD from the beam 316 to the second metering device 312. Further, the plurality of elastic strands 318 can be stretched along the machine direction MD between the beam 316 and the second metering device 312. The stretched elastic strands 318 can also be joined to the first substrate 306 and the second substrate 308 in the second metering device 312 to produce the elastomer laminate 302. However, it should be noted that in some configurations, the elastic strands 318 are not arranged in beam form. Instead, for example, the first metering device 310 can be a spool of individual elastic strands 318 or, alternatively, a spool of elastic strands 318 that are not formed on a beam. In this way, the systems and methods described herein are applicable across a range of manufacturing processes that generally require adhering one or more elastic strands to one or more substrates.

[0049] As shown in FIG. 4, the second metering device 312 includes a first roller 324 having an outer peripheral surface 326 and rotating around a first rotation axis 328, and a second roller 330 having an outer peripheral surface 332 and rotating around a second rotation axis 334. The first roller 324 and the second roller 330 rotate in opposite directions, and the first roller 324 may be adjacent to the second roller 330 to define a nip 336 between the first roller 324 and the second roller 330. The first roller 324 rotates such that the outer peripheral surface 326 has a surface speed V1, and the second roller 330 can rotate such that the outer peripheral surface 332 has the same or substantially the same surface speed V1.

[0050] As shown in FIGS. 4 and 5, the first substrate 306 includes a first surface 338 and an opposing second surface 340, and the first substrate 306 advances toward the first roller 324. Specifically, the first substrate 306 advances toward the first roller 324 at a speed V1, the first substrate 306 partially wraps around the outer peripheral surface 326 of the first roller 324, and advances through the nip 336. Accordingly, the first surface 338 of the first substrate 306 contacts the outer peripheral surface 326 of the first roller 324 and advances in the same direction as the outer peripheral surface 326 of the first roller 324. In addition, the second substrate 308 includes a first surface 342 and an opposing second surface 344, and the second substrate 308 advances toward the second roller 330. Specifically, the second substrate 308 advances toward the second roller 330 at a speed V1, the second substrate 308 partially wraps around the outer peripheral surface 332 of the second roller 330, and advances through the nip 336. Accordingly, the second surface 344 of the second substrate 308 contacts the outer peripheral surface 332 of the second roller 330 and advances in the same direction as the outer peripheral surface 332 of the second roller 330.

[0051] Continuing to refer to FIGS. 4 and 5, the beam 316 has an elastic strand 318 wound thereon, and the beam 316 is rotatable about a first beam rotation axis 346. In some configurations, the first beam rotation axis 346 may extend in the transverse direction CD. When the beam 316 rotates, the plurality of elastic strands 318 advance from the beam 316 at a speed V2, and the plurality of elastic strands 318 are spaced from each other by about 0.25 mm to about 4 mm, or about 0.25 mm to about 3 mm, or about 0.25 mm to about 2 mm in the transverse direction CD. From the beam 316, the plurality of elastic strands 318 advance to the nip 336 in the machine direction MD. In some configurations, the speed V2 is less than the speed V1, and thus the plurality of elastic strands 318 may be stretched in the machine direction MD. The plurality of stretched elastic strands 318 then pass through the nip 336 between the first substrate 306 and the second substrate 308 such that the plurality of elastic strands 318 are joined to the second surface 340 of the first substrate 306 and the first surface 342 of the second substrate 308 to produce a continuous length of the elastomeric laminate 302. As shown in FIG. 4, the first substrate 306 may pass through an adhesive applicator device 348 that applies an adhesive 350 to the second surface 340 of the first substrate 306 before advancing to the nip 336. It should be understood that the adhesive 350 can be applied to the first substrate 306 upstream of the first roller 324 and / or while the first substrate 306 is partially wound around the outer peripheral surface 326 of the first roller 324. It should be understood that the adhesive may be applied to the plurality of elastic strands 318 before and / or between being joined to the first substrate 306 and the second substrate 308. Further, it should be understood that the adhesive may be applied to the first surface 342 of the second substrate 308 before or between being joined to the plurality of elastic strands 318 and the first substrate 306.

[0052] It should be understood that different components can be used to construct the elastomeric laminate 302 by the methods and apparatuses of this specification. For example, the first substrate 306 and / or the second substrate 308 can include a nonwoven material and / or a film. Further, the plurality of elastic strands 318 can be configured in various ways and to have various dtex values. In some configurations, the plurality of elastic strands 318 may be configured to have a dtex value in the range of from about 10 dtex to about 500 dtex, or from about 10 dtex to about 400 dtex, or from about 10 dtex to about 300 dtex, specifically enumerating all values in 1 dtex increments within the above ranges, and all ranges within or formed by the above ranges. It should also be understood that the beam 316 can be constructed in various ways and with various amounts of elastic strands. Exemplary beams, also referred to as leveling beams that can be used in the apparatus and methods of this specification, are disclosed in U.S. Patent Nos. 4,525,905, 5,060,881, and 5,775,380, and U.S. Patent Application Publication No. 2004 / 0219854(A1). FIG. 5 shows nine elastic strands 318 advancing from beam 316, but it should be understood that the apparatus of this specification may be configured such that more or fewer than nine elastic strands 318 advance from beam 316. In some configurations, the plurality of elastic strands 318 advancing from beam 316 may include from about 100 to about 2,000 strands, specifically enumerating all values in increments of 1 strand within the above range, and all ranges within or formed by the above range. In some configurations, the elastic strands 318 may be separated from each other by about 0.5 mm to about 4 mm in the transverse direction, specifically enumerating all values in increments of 0.1 mm within the above range, and all ranges within or formed by the above range. The elastomer within the plurality of elastic strands may be pre-tensioned before joining the elastic strands to the first substrate layer or the second substrate layer 306, 308. In some configurations, the elastomer may be pre-tensioned to about 75% to about 300%, specifically enumerating all values in increments of 1% within the above range, and all ranges within or formed by the above range. It should also be understood that one or more beams of elastomer can be arranged along the cross-direction CD of the processing process and / or along the machine direction MD at various different portions of the processing process. It should also be understood that beam 316 can be connected to one or more motors, such as a servo motor, to drive and control the rotation of beam 316.

[0053] It should also be understood that the plurality of elastic strands 318 may have various different material structures and / or dexterity values to create an elastomeric laminate 302 having different stretch and shrink characteristics in different regions. In some configurations, the elastomeric laminate may have regions where the elastic strands are spaced relatively close to each other in the transverse direction CD and other regions where the elastic strands are spaced relatively far from each other in the transverse direction CD to create different stretch characteristics in different regions. In some configurations, the elastic strands may be supplied onto the beam in a stretched state and thus may not require (or may require relatively little additional stretching) additional stretching before being combined with the first substrate 306 and / or the second substrate 308.

[0054] Referring now to FIG. 7, the adhesion of the elastic strands 318 to the first substrate 306 is schematically shown. As described above, elastic strands wound in a beam configuration under high compression tend to stick (i.e., crosslink) during unwinding. Thus, according to the present disclosure, a control layer 352 can be applied to the elastic strands 318 of the beam 316 to reduce crosslinking and assist in the unwinding process. Further, since the elastic strands 318 can be adhered to the first and second substrate layers 306, 308 via an adhesive 350 (note that only the first substrate 306 is shown in FIG. 7 for illustrative purposes), the various properties of the control layer 352 and the adhesive 350 can be specifically selected to enable sufficient adhesion of the elastic strands 318 and the first and second substrate layers 306, 308. More specifically, the control layer 352 applied to the beam 316 can have a solubility level that ensures that most of the control layer 352 remains on the surface of the plurality of elastic strands 318 as opposed to being absorbed by the strands. This property of the control layer 352 is schematically shown by the enlarged view 318A of FIG. 7. Thus, when the plurality of elastic strands 318 are withdrawn from the beam 316, unwanted blocking can be reduced or eliminated even after the beam 316 has been stored under high compression for a period of time prior to unwinding of the elastic strands 318.

[0055] However, importantly, the plurality of elastic strands 318 must also be sufficiently adhered to the first and second substrate layers 306, 308 to form an elastomeric laminate 302 having the desired strength parameters. Therefore, the adhesive 350 can be specifically selected to absorb the control layer 352 such that the control layer 352 does not adversely affect the adhesion of the adhesive 350 to the plurality of elastic strands 318. Thus, according to the present disclosure, the plurality of elastic strands 318, the control layer 352 applied to the plurality of elastic strands 318, and the adhesive 350 are each specifically selected such that the control layer 352 is difficult to be absorbed by the plurality of elastic strands 318 and is instead easily absorbed by the adhesive 350. As a result, the elastic strands 318 can be withdrawn from the beam 316 without blocking, and the adhesive 350 can sufficiently adhere the elastic strands 318 and the first and second substrates 306, 308.

[0056] The desired distribution level within the elastomeric laminate 302 can be achieved by selecting a control layer 352 having specific solubility parameters and a number average molecular weight. In particular, the control layer 352 can have a solubility parameter in the range of about 15.5 MPa 1 / 2 to about 16.5 MPa 1 / 2 , or about 15.8 MPa 1 / 2 to about 16.5 MPa 1 / 2 and a number average molecular weight in the range of about 0.6 kg / mol to 1.5 kg / mol, or about 0.8 kg / mol to about 1.4 kg / mol, or about 1.0 kg / mol to about 1.3 kg / mol. The control layer 352 can have a surface tension of about 24 mN / m to about 30 mN / m. Further, the adhesive 350 can include an adhesive polymer having a solubility parameter in the range of about 16 MPa 1 / 2 to about 17.5 MPa 1 / 2 , or about 16.5 MPa 1 / 2 to about 17.2 MPa 1 / 2 . The plurality of elastic strands 318 can have a solubility parameter in the range of about 18 MPa 1 / 2 to about 18.5 MPa 1 / 2may include a strand polymer having a solubility parameter within the range of. According to one embodiment, the strand polymer has a solubility parameter of about 18.3 MPa 1 / 2 Furthermore, the number average molecular weight of the control layer may be lower than the molecular weight of each of the strand polymer of the plurality of elastic strands 318 and the adhesive polymer of the adhesive 350.

[0057] For a pair of materials a and b, the χ value associated with their mixing is calculated as follows.

[0058] [Number] wherein K is 1.38e-23 J / K (Boltzmann constant), υ is the volume (cubic meters) of the repeating unit of the component with the higher molecular weight, T is the temperature (Kelvin), the δ values are the solubility parameters ((MPa)^0.5) of components a and b.

[0059] According to the present disclosure, the χN value between the control layer 352 and the strand polymer of the elastic strand 318 is greater than 2, where N is the degree of polymerization of the control layer and χ is the Flory-Huggins interaction parameter (for additional information regarding the determination of χN according to the present disclosure, see "The Physics of Polymers", Gert R. Strobl, ISBN 978-3-642-06449-4). Furthermore, the χN value between the control layer 352 and the adhesive polymer of the adhesive 350 may be less than about 3, or less than about 2. The adhesive 350 may have a rubbery plateau modulus of about 0.01 to about 0.3 MPa at 38°C and 1 Hz, 0.02 to about 0.1 MPa at 38°C and 1 Hz, or about 0.1 MPa at 38°C and 1 Hz (for additional information regarding the determination of the plateau modulus according to the present disclosure, see Pocious A.V., "Adhesion and Adhesives Technology - an introduction, 2 nd"Edition". Hanser / Gardner Publications, Inc., Cincinnati, OH (2002). See ISBN 1-56990-319-0, pages 124-131). Further, the tensile elastic modulus of the plurality of elastic strands 318 at room temperature can be in the range of about 5 MPa to about 15 MPa (for additional information regarding the determination of the tensile elastic modulus according to the present disclosure, see Pocious A.V., "Adhesion and Adhesives Technology - an introduction, 2 nd "Edition". Hanser / Gardner Publications, Inc., Cincinnati, OH (2002). See ISBN 1-56990-319-0, pages 17-18). After the formation of the elastomeric laminate 302, the control layer 352 can disperse from its original position on the surface of the elastic strand 318 when absorbed by the adhesive 350.

[0060] As described above, the beamed elastomer according to the present disclosure can be formed from spandex fibers. One type of spandex fiber is a "polyurethane urea" elastomer or a "high hard segment level polyurethane" elastomer, and can be formed into fibers using a solution (solvent) spinning process (as opposed to being processed in a molten state). The rigid blocks in polyurethane urea provide strong chemical interactions that are important for providing "fixation" that enables good stress relaxation performance at temperatures near body temperature on the time scale corresponding to wearing diapers, including overnight. This type of fixation enables better force relaxation over time (i.e., when held in a stretched state at body temperature, there is little attenuation of the force over time). In contrast, the extruded strands and scrims are typically made from styrene block copolymers or thermoplastic elastomers that can be formed in a molten state by conventional extrusion processes. Thermoplastic elastomers include compositions such as polyolefins, polyurethanes (polyurethanes with hard segment melting below 200 °C), etc. These thermoplastic elastomers such as polyurethanes (polyurethanes with hard segment melting below 200 °C) are more prone to higher stress relaxation during use because they can be melted / remelted and extruded, which is a major drawback. The styrene block copolymer used in the extruded strands comprises a relatively long rubbery intermediate block located between relatively short end blocks. End blocks that are short enough to allow a conventional extrusion process with good flow often have a strong tendency towards stress relaxation and are often subject to stress relaxation over time. The urea bonds present in spandex need to be made by a spinning process. Spandex cannot be melted / remelted like a styrene block copolymer. The spandex prepolymer is combined with a solvent and additives and the solution is spun to make solid spandex fibers. A plurality of fibers can then be formed together to make a single spandex strand. The decitex of a single spandex fiber can be about 15, and thus a 500 decitex strand can have nominally 33 fibers wound together to make one strand. Depending on the decitex used in the beam process, there can be 40 fibers (or filaments), 30 fibers, 20 fibers, 15 fibers, 8 fibers, 5 fibers, 3 fibers, or even up to 2 fibers. The spandex fibers can be single-component or bicomponent (as disclosed in WO201045637(A2)).

[0061] Commercially available spandex strands are also known as Lycra, Creora, Roica, or Dorlastan. Spandex is often referred to as elastane fiber or polyurethane fiber. The LYCRA HYFIT strand, a product of Invista, Wichita, Kansas, is suitable for making strands that comprise a plurality of elastomers 318 that make up the elastomeric laminate 302. Some strands, such as the aforementioned LYCRA HYFIT, can comprise a plurality of individual fibers wound together to form the strand. With respect to elastic strands formed from a plurality of individual fibers, the individual fibers can move relative to each other, thereby changing the cross-sectional shape of the strand and becoming untwisted, resulting in insufficient control of the strand and insufficient bonding / adhesion / jointing of the elastic strand to one or both of the first substrate layer 306 and the second substrate layer 308 of the elastomeric laminate 302. It has been found that in order to minimize the drawbacks associated with strands comprising a plurality of fibers, it is advantageous to minimize the number of fibers within a given strand. Thus, it is desirable to have less than about 40 fibers per strand, less than about 30 fibers per strand, less than about 20 fibers per strand, less than about 10 fibers per strand, less than about 5 fibers per strand, and one fiber forming the strand. When a single fiber forms a strand capable of providing performance equivalent to that of strands of multiple fibers of the prior art, it is desirable that the fiber decitex of the fiber be from about 22 to about 300 and the fiber diameter be from about 50 micrometers to about 185 micrometers.

[0062] As described above, the control layer 352 helps prevent blocking when the plurality of elastic strands 318 are wound around a spool or beam, and at the same time reduces the friction coefficient of the strands. According to some embodiments, the control layer 352 is mineral oil, which can be, for example, paraffinic mineral oil. According to various embodiments, the control layer 352 can include, for example, any of white mineral oil, polyisoprene, and polybutadiene. In other embodiments, the control layer can be synthetic oil.

[0063] The control layer 352 can include additional materials, such as soap (i.e., fatty acid or fatty acid salt), wax, detergent, clay, or anti-caking agent (e.g., silica), to assist in its performance. The use of soap according to the present disclosure is thought to reduce the adhesiveness of the elastic strands, which can improve handling in the winding process. Further, the use of soap can also provide a beneficial trade-off between unwindability and adhesiveness.

[0064] In some embodiments, for example, a metal soap may be added to the control layer 352 that functions to improve the unwindability of the plurality of elastic strands 318 from the beam 316. As used herein, the metal soap can be a fatty acid salt produced by the reaction of an alkali metal, alkaline earth metal, or transition metal with a saturated, unsaturated straight-chain or branched-chain aliphatic carboxylic acid having 8 to 22 carbon atoms, or 12 to 18 carbon atoms. Examples include saturated fatty acids such as stearic acid (octadecanoic acid), lauric acid (dodecanoic acid), 12-hydroxystearic acid, and mixtures of acids having 8 to 22 carbon atoms, unsaturated fatty acids such as oleic acid (cis-9-octadecenoic acid) and linoleic acid (9,12-octadecadienoic acid), synthetic carboxylic acids such as isostearic acid, 2-ethylhexanoic acid, dimethylhexanoic acid, trimethylhexanoic acid, and mixtures of synthetic aliphatic isocarboxylic acids, and salts of alicyclic naphthenic acids and resin acids. Various metal ions can be used to make the metal soap, examples of which include sodium, magnesium, calcium, and zinc. According to one embodiment of the present disclosure, magnesium stearate is used because it is not soluble in either the adhesive 350 or the elastic strand 318. The amount of soap utilized can vary, but in some embodiments, the control layer 352 contains about 1 wt% to 5 wt% soap, or about 2 wt% to 4 wt% soap, or about 3 wt% soap.

[0065] Referring now to FIG. 8, the time-dependent interaction of the control layer 352 with the plurality of elastic strands 318 and the adhesive 350 is schematically shown. As shown by the enlarged view 318A, the control layer 352 is schematically shown to generally coat the outer surface of the elastic strand 318. The control layer 352, when having a high molecular weight, will not be significantly absorbed by the elastic strand 318 even when the beam 316 is stored under high compression for an extended period of time. Therefore, the control layer 352 functions to beneficially prevent crosslinking and blocking when the elastic strand 318 is finally withdrawn from the beam 316 during the manufacturing process. As described above with reference to FIG. 4, the processing apparatus 300 manufactures an elastomeric laminate 302 formed by a first substrate 306, a plurality of elastic strands 318, and a second substrate 308. As shown in FIG. 8, an adhesive 350 can be used to adhere the plurality of elastic strands 318 to the first and second substrates 306, 308. At a first time point shown as time T1 in FIG. 8, the control layer 352 has begun to disperse within the elastomeric laminate 302A. In particular, as described above, due to the relative solubility and number average molecular weight of the various components of the elastomeric laminate 302, the control layer 352 of the present disclosure can be mainly absorbed by the adhesive 350. When the control layer 352 is absorbed by the adhesive 350, the adhesive 350 can adhere properly to the elastic strands 318. Finally, at a second time point shown as time T2 in FIG. 8, the control layer 352 has completed dispersion and can be substantially absorbed by the adhesive 350. Further, at T2, if the control layer 352 contains soap, the soap does not disperse within the adhesive 350. Instead, the soap will remain in large amounts between the interface of the elastic strands 318 and the adhesive 350. For this reason, if excessive soap is used, it may thereby impair the adhesion of the first and second substrates 306, 308 to the elastic strands 318. As shown, in FIG. 8, the adhesive 350 can contact a portion of the elastic strands 318. Alternatively, the adhesive 350 can substantially or completely wrap one or more of the elastic strands 318.

[0066] Without conflicting with what is outlined above, desirably, forming the elastomeric laminate 302 using the control layer 352 together with the plurality of elastic strands 318 and the adhesive 350 does not result in laminate properties that are significantly different from the same elastomeric laminate 302 made without the control layer 352. For example, the elastomeric laminate of the present disclosure including the control layer can have a laminate creep of 5 mm or less, 4 mm or less, or 3 mm or less according to a laminate creep test. These laminate creep values are for laminates made of an elastomer containing a control layer, and are evidence that the control layer of the present disclosure does not affect the performance of the adhesive. Further, the elastomeric laminate of the present disclosure formed of elastic strands containing a control layer can have a laminate creep within 2 mm or within 1 mm of the same elastomeric laminate formed of elastic strands not containing a control layer. In fact, the elastomeric laminate containing a control layer can have less (i.e., less creep) laminate creep than the same elastic laminate not containing a control layer.

[0067] Further, the elastomeric laminate of the present disclosure containing a control layer can have a static peel force time exceeding 700 minutes / 10 mm bond length, exceeding 600 minutes / 10 mm bond length, exceeding 500 minutes / 10 mm bond length, or exceeding 400 minutes / 10 mm bond length, or exceeding 300 minutes / 10 mm bond length, in accordance with the static peel force time test method. These static peel force time values are for laminates made of an elastomer containing a control layer, and are evidence that the control layer of the present disclosure does not affect the performance of the adhesive. Further, the elastomeric laminate of the present disclosure formed of elastic strands containing a control layer can have a static peel force time within 5 minutes / 10 mm bond length or within 3 minutes / 10 mm bond length of the same elastomeric laminate formed of elastic strands not containing a control layer, and in fact, the elastomeric laminate containing a control layer can have a longer (i.e., longer time) static peel force time than the same elastic laminate not containing a control layer.

[0068] Furthermore, the elastomeric laminate of the present disclosure including the control layer can have a time-dependent stress relaxation of about 5% to about 30%, about 5% to about 25%, about 10% to about 25%, or about 15% to about 20% according to the method of time-dependent stress relaxation. These values of time-dependent stress relaxation are for laminates made of elastomers including the control layer, and are evidence that the control layer of the present disclosure does not affect the performance of the adhesive. Furthermore, the elastomeric laminate of the present disclosure formed of elastic strands including the control layer can have a time-dependent stress relaxation within 15% or within 10% of the same elastomeric laminate formed of elastic strands without the control layer. In fact, the elastomeric laminate including the control layer can have less (i.e., less stress relaxation) time-dependent stress relaxation than the same elastic laminate without the control layer. The dimensions and values disclosed herein should not be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise indicated, each such dimension is intended to mean both the recited value and the functionally equivalent range surrounding that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm".

[0069] All documents cited herein, including any patents or patent applications that are cross-referenced or related, and any patent application or patent for which this application claims priority or the benefit thereof, are incorporated herein by reference in their entirety unless expressly excluded or limited. The citation of any document is not to be construed as an admission that it is prior art to any invention disclosed or claimed herein, or that it alone or in any combination with any other reference(s) teaches, suggests, or discloses any such invention. Further, if any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition given to the term in this document shall apply.

[0070] While 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 can be made without departing from the spirit and scope of the invention. Accordingly, it is intended that all such changes and modifications within the scope of the invention be covered by the appended claims.

[0071] Test Procedure Unless otherwise specified, the tests are carried out under standard laboratory conditions of 22 °C and 50% relative humidity.

[0072] Force Relaxation over Time The force relaxation over time of the test specimens is measured on a constant speed tensile testing machine using a load cell such that the measured force is within 1% to 90% of the cell's limit (a suitable instrument is MTS Insight using Testworks 4.0 Software, available from MTS Systems Corp. (Eden Prairie, MN)). Prior to analysis, the articles are conditioned at 23 °C ± 2 °C and 50% ± 2% relative humidity for 2 hours and then tested under the same environmental conditions. The sample size is prepared such that a gauge length of 25.4 mm (parallel to the elastic stretch) is possible at a width of 12.7 mm.

[0073] The tensile testing machine is programmed to determine the engineering strain when the elongation is carried out until the tensile force reaches 0.0294 N / mm.

[0074] For the test of force relaxation over time, a second sample is prepared and conditioned as described above. The test is carried out on the same apparatus as described above. The test is carried out at a temperature of 37.8 °C. The sample is stretched to the strain determined above. The sample is held for 10 hours and the force is recorded at a rate of at least 5 Hz during the application of the strain, at least 5 Hz during the first minute of force relaxation, and then at least 0.05 Hz (one point every 20 seconds) throughout the experiment.

[0075] Laminated Body Creep Test Method ("Laminated Body Creep") The laminate creep test method is used to characterize the movement of the end of the stretched elastic strand 318 of the stretched elastomeric laminate in a direction away from the cut edge 472 of the same laminate.

[0076] Device The stretch board 400 is prepared from an acrylic plate or a polycarbonate plate, and an example thereof is shown in FIG. 9. The width of the stretch board 400 is 250 to 375 mm, and the length of the stretch board 400 is at least the length at which the laminate to be tested becomes wide. The hook material 402 capable of fixing the elastomeric laminate is attached to the front side of the stretch board 400 and extends in the longitudinal direction. Two courses of hooks 402, each having a width of about 50.8 mm and extending along the length of the stretch board 400, are symmetrically positioned about the center line 404 of the stretch board 400. As a result, there is a 12 mm gap (shown as gap "G") between the courses of the hooks, whereby the exposed acrylic or polycarbonate plate extending over the entire length of the stretch board 400 where no hook is attached is exposed. Two courses of hooks 406, at least 13 mm wide and extending along the length of the plate, are attached to the back side of the widthwise edges of the plate to facilitate holding the stretched laminate across the entire width of the front side of the plate.

[0077] Preparation of Samples Five similar test pieces representing the sample elastomeric laminate are cut. The test piece of the elastomeric laminate, in its stretched state, is at least the same width as the stretch board 400 prepared above and is the cut portion so as to be wound around the widthwise edges of the stretch board 400 and fixed by the hook material 406 on the back side. Each test piece of the elastomeric laminate may be taken from a roll stock or, if roll stock is not available, cut from a finished disposable absorbent article.

[0078] As shown by test piece 450 in FIG. 10, each elastomer laminate test piece has the elastic strands 318 sufficiently extended so as to extend in the width direction of the stretch board 400, perpendicular to the course of the hook 402 extending along the length of the stretch board, and is disposed on the stretch board 400. The test piece 450 is held in a stretched state positioned by two courses of hook material 402 extending along the length of the stretch board 400. Although the test piece 450 remains in a stretched state, the ends of the test piece are wrapped around the widthwise edges of the stretch board 400 and fixed to the back hook material 406 to hold the entire laminate of the stretched test piece 450.

[0079] Using a black permanent marker, mark a 5 mm line 462 (FIGS. 10 and 11) in the width direction of the test piece laminate. This black marker is applied thick enough so that the elastic strands 318 of the underlying element of the elastomer laminate are blackened. The line extends in the length direction of the stretch board, is located at the center of the stretch board 400, and is at the center of a 12 mm gap between two courses of hook material 402 extending in the length direction. Then, using a utility knife or razor blade, cut the laminate along the center line 404 at the center of this 5 mm wide line 462. Then, place the stretch board 400 to which the cut test piece laminate is attached in an oven at 38° C. for 120 minutes.

[0080] Measurement and Analysis After being placed in the oven for 120 minutes, the stretch board 400 is taken out and analyzed immediately as shown in FIG. 11. The ends of the elastic strands 318 that have undergone significant creep from the starting stretched position are clearly shown as black dots 452 that have moved in a direction away from the center line 404. Record the widthwise distance (distance “C”) in millimeters from each of the cut edges 472 to the displaced black dots. In total, five similar elastomer laminate test piece replicas are analyzed in this way. Calculate the arithmetic mean of the recorded displacement distances among the five replicated test pieces and report it in millimeters as the “laminate creep”.

[0081] Static Peel Force Time Test Method ("Static Peel Force Time") The static peel force time test method is used to determine the time required for the elastomeric laminate to completely delaminate in a peel configuration of approximately 180° at a fixed temperature under a constant load. The peel is conducted such that the crack of the peel propagates parallel to the elastic strands of the elastomeric laminate. A plurality of test specimens of a representative sample elastomeric laminate are obtained from rollstock (if available) or one or more disposable absorbent articles and analyzed to establish the static peel force time.

[0082] Sample Preparation If the elastomeric laminate is available in rollstock, ten test specimens with a machine direction of 27 mm and a cross - direction of 25.4 mm are randomly obtained from the equilibration rollstock. If an exemplary laminate is not available as rollstock, the laminate test specimens are cut from one or more completed disposable absorbent articles. In this case, the test specimens must have a length parallel to the direction of the elastic strands of 27 mm and a length perpendicular to the direction of the elastic strands of 25.4 mm.

[0083] For each test specimen, the non - woven layer of the laminate is manually peeled by 10 - 15 mm in a direction parallel to the elastic strands. (A fleece spray may be used very locally to enable separation of the non - woven fabric.) For each replica, the dimensions of the remaining bonded area in the direction parallel to the elastic strands are measured and recorded in 1 - mm increments.

[0084] Regardless of where the test specimens for peel analysis are supplied from, each of the unbonded layers at the edge of the laminate is separately folded and wrapped around a small round wooden dowel with a diameter of 2 mm and a length of approximately 40 mm, and the wrapped dowel is fixed with a double clip that is 2 inches wide. Place the clip on the wrapped dowel and fix it to the double - folded layer of the material so that the material does not slip or come out of the clip.

[0085] Measurement With the clip attached, place the test piece in an incubation chamber (38 ± 1 °C) that has been pre-conditioned for approximately 2 hours before the test. After 2 hours, suspend each sample in the chamber by a clip attached to one of the laminate layers, and attach a weight to the clip of the other laminate layer and suspend it. The total mass of the suspended weight, double clip, and mandrel is 200 ± 2 g.

[0086] Suspend each test piece so that the bottom of the attached weight is positioned at a sufficient height above the bottom of the chamber such that the entire laminate can peel and the weight can freely fall to the bottom of the chamber through some remaining distance. Use a timer to measure the time between the time the suspended weight is attached and the time the bonded area of the test laminate completely delaminates. For each test piece, record the time to this failure in minutes.

[0087] Analysis and Reporting For each test piece, normalize the time to failure to a bond dimension of 10 mm to establish the normalized suspension time of the test piece, and record it in minutes for each test piece.

[0088]

Number

[0089] Calculate the arithmetic mean of the normalized suspension time values of 10 test pieces and report it in minutes as the static peel force time.

[0090] Average Decitex (“Average Dtex”) Using the average dtex method, the average Dtex for elastic fibers present in a complete article or in a test piece of a subject extracted from an article is calculated on a length-weighted basis. The dtex value is the mass in grams of the fibers present in 10,000 meters of that material in a relaxed state. The dtex value of an elastic fiber or an elastomeric laminate containing elastic fibers is often reported by the manufacturer as part of the specification of the elastic fiber or the elastomeric laminate containing elastic fibers. The average Dtex can be calculated from these specifications if available. Alternatively, if these specified values are not known, the dtex value of an individual elastic fiber is determined by determining the cross-sectional area of the fiber in a relaxed state via a suitable microscopy technique such as scanning electron microscopy (SEM), determining the composition of the fiber via Fourier Transform Infrared (FT-IR) spectroscopy, and then using literature values for the density of the composition to calculate the mass in grams of the fibers present in 10,000 meters of fiber. The dtex values for individual elastic fibers removed from a complete article or a sample extracted from an article, provided by the manufacturer or measured experimentally, are used in the equation described below, in which the length-weighted average of the dtex values between the elastic fibers present is determined.

[0091] If the length of each elastic fiber present in an article or a sample extracted from the article is known, it is calculated from the component dimensions of the article having the component or the overall dimensions of the sample, and the elastic fiber pre-strain ratio associated with the component of the article having the component or the sample. Alternatively, if the dimensions and / or the elastic fiber pre-strain ratio are not known, the absorbent article or the sample extracted from the absorbent article is disassembled and all the elastic fibers are removed. This disassembly can be performed, for example, by gently heating to soften the adhesive, using a cryogenic spray (e.g., Quick-Freeze® of Miller-Stephenson Company, Danbury, Connecticut), or using a suitable solvent that removes the adhesive but does not expand, modify, or break the elastic fibers. Measure the length of each elastic fiber in the relaxed state and record it to the nearest millimeter (mm) in millimeters (mm).

[0092] Calculation of Average Dtex Relaxed length L present in a test piece extracted from an absorbent article or an absorbent article i and fiber decitex value d i (either obtained from the manufacturer's specifications or measured experimentally) for each individual elastic fiber f i of the absorbent article or the test piece extracted from the absorbent article, the average Dtex thereof is defined as follows:

[0093]

Equation

[0094] If the decitex value of any individual fiber is not known from the specifications, it is determined experimentally as described below, and the resulting fiber decitex value is used in the above equation to determine the average Dtex.

[0095] Experimental Determination of Fiber Decitex Value For each of the elastic fibers taken from an absorbent article or a sample extracted from an absorbent article according to the above procedure, each elastic fiber L k is measured for its relaxed length and recorded to the nearest millimeter (mm). Each elastic fiber is analyzed via FT-IR spectroscopy to determine its composition, and its density ρ k is determined from available literature values. Finally, each fiber is analyzed via SEM. The fiber is cut vertically at three approximately equal positions along its length using a sharp blade to create a clean cross-section for SEM analysis. The three fiber sections with their cross-sections exposed are mounted in a relaxed state on an SEM sample holder, sputter-coated with gold, introduced into the SEM and analyzed, and imaged at a resolution sufficient to clearly elucidate the fiber cross-section. To minimize any oblique strain in the measured cross-section, the fiber cross-section is oriented as perpendicular as possible to the detector. The shape of the fiber cross-section can vary and some fibers may consist of multiple individual filaments. In any case, the area of each of the three fiber cross-sections is determined (e.g., the diameter of a circular fiber, the major and minor axes of an elliptical fiber, and using image analysis for more complex shapes), and the average of the three areas a k of the elastic fiber is recorded in square micrometers (μm 2 ) to the nearest 0.1 μm 2 . The decitex d k of the k-th measured elastic fiber is calculated as follows:

[0096]

Equation

[0097] Average strand interval Using a gauge accurate to the nearest 0.5 mm calibrated against a certified NIST gauge, measure the distance in 0.5 mm increments between two distal strands within a section, and then divide by the number of strands in that section minus 1. Average strand interval = d / (n - 1) (where n > 1) Report in 0.1 mm increments.

Claims

1. A disposable absorbent article in the form of a diaper or absorbent pants, comprising a liquid permeable topsheet (138), a liquid impermeable backsheet (136), and an absorbent core (140) disposed between said topsheet (138) and said backsheet (136), an elastomeric laminate (302) including a plurality of elastic strands (318) spaced apart from one another and joined to a nonwoven web material (306) by an adhesive (350); The elastic strands (318) include a strand polymer, the strand polymer having a strength of about 18 MPa. １／２ ~Approx. 18.5MPa １／２ and the adhesive (350) comprises an adhesive polymer, the adhesive polymer having a solubility parameter in the range of about 16 MPa. １／２ ~Approx. 17.5MPa １／２ having a solubility parameter in the range The elastic strand (318) is supplied from a winding supply of elastic strand, the winding supply of elastic strand being at a pressure of about 15.5 MPa. １／２ ~Approx. 16.5MPa １／２ and a number average molecular weight in the range of about 0.6 kg / mol to about 1.5 kg / mol.

2. 10. The disposable absorbent article of claim 1, wherein the number average molecular weight of the control layer is lower than the molecular weight of each of the strand polymer and the adhesive polymer.

3. 3. The disposable absorbent article of claim 1 or 2, wherein the χN value between the control layer and the strand polymer is greater than 2 and the χN value between the control layer and the adhesive polymer is less than 2, where N is the degree of polymerization of the control layer and χ is the Flory-Huggins interaction parameter.

4. The strand polymer is about 18.3 MPa １／２ The disposable absorbent article according to any one of claims 1 to 3, having a solubility parameter of

5. The disposable absorbent article of any one of claims 1 to 4, wherein said elastomeric laminate has a laminate creep of 5 millimeters or less when said elastomeric laminate is subjected to a Laminate Creep Test.

6. The disposable absorbent article of any one of claims 1 to 5, wherein said elastomeric laminate has a static peel force time of greater than 700 min / 10 mm.

7. The disposable absorbent article of any one of claims 1 to 6, wherein said adhesive at 38°C has a plateau modulus of about 0.1 MPa at 38°C and 1 Hz.

8. The disposable absorbent article of any one of claims 1 to 7, wherein the tensile modulus of said elastic strands at room temperature is in the range of about 5 MPa to about 15 MPa.

9. The disposable absorbent article of any one of claims 1 to 8, wherein the elastomeric laminate comprising the elastomeric strands forms at least a portion of a disposable article component selected from the group consisting of a belt, an ear, a side panel, a cuff, a waistband, a backsheet, and a topsheet.

10. The disposable absorbent article of any one of claims 1 to 9, wherein said control layer is mineral oil.

11. The disposable absorbent article of claim 10, wherein said mineral oil is a paraffin-based mineral oil.

12. The disposable absorbent article of any one of claims 1 to 9, wherein the control layer comprises one of white mineral oil, polyisoprene, and polybutadiene.

13. The disposable absorbent article of any one of claims 1 to 9, wherein said control layer is a synthetic oil.

14. A disposable absorbent article according to any one of the preceding claims, wherein said control layer comprises soap, said soap being preferably magnesium stearate.

15. The disposable absorbent article of any one of claims 1 to 14, wherein said strand polymer comprises a segmented polyurethane and said adhesive polymer comprises a styrenic block copolymer.

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