Patent Application
20220071311
The present invention relates to pant-type wearable articles having an elastic belt with improved regularity of gathers, improved comfort and softness, while providing good fit.
Infants and other incontinent individuals wear absorbent articles such as diapers to receive and contain urine and other body exudates. Pull-on absorbent articles, or pant-type absorbent articles, are those which are donned by inserting the wearer's legs into the leg openings and sliding the article up into position about the lower torso. Pant-type absorbent articles have become popular for use on children who are able to walk and often who are toilet training, as well as for younger children who become more active in movement such that application of taped-type absorbent articles tends to be more difficult, and also for younger babies requiring a soft fit around the waist opening and leg openings.
Pant-type articles may take various structures wherein the circumference of the waist opening and vicinity thereof is made elastic enough to facilitate the wearer or the caregiver to expand the article and insert the wearer's legs into the leg openings for wearing the article. The region of the waist circumference and vicinity thereof is often referred to as the elastic belt. One type of structure for the pant-type article is the belt-type pant having a central chassis to cover the crotch region of the wearer and a separate elastic belt defining the waist opening and leg opening, such as described in PCT Publication WO 2006/17718A. Another type of structure for the pant-type article is the uni-body pant configured such that the outer cover of the article completely covers the entirety of the garment-facing surface of the article, wherein the portion configured to stretch about the torso is considered the elastic belt region.
Whatever the structure of the pant-type article may be, pant-type articles provide only a very small range of size adjustment or body configuration adjustment based on the structural limitations of the article. As such, pant-type articles are typically so configured to accommodate size and configuration ranges by providing the elastic belt region very stretchable and comfortable to wear, yet with reliable fit such that sufficient protection against sagging and leakage may be provided. Further, the elastic belt region may be the portion which is most touched and observed by the wearer or the caregiver upon use, and thus its properties most associated with the quality of the article. By quality, what may be desired is an undergarment-like appearance provided by aesthetically pleasing regularity of gathers.
Based on the foregoing, there is a need for a wearable article providing improved stretchability for ease of application, improved fit for preventing sagging, improved comfort and softness, and improved breathability for skin health. There is also a need for a wearable article having improved regularity of gathers which intuitively communicates high quality. There is also a need for providing such a wearable article which can be economically made.
The present invention is directed to a wearable article continuous in a longitudinal direction and a transverse direction comprising a front elastic belt region, a back elastic belt region, a crotch region, a waist opening, and a pair of leg openings; the crotch region extending longitudinally between the front elastic belt region and the back elastic belt region;
wherein each of the front and back elastic belt region comprises a laminate comprising an inner sheet, an outer sheet, and a plurality of elastic members running in the transverse direction,
wherein the laminate further comprising an elastic bonding which continuously bonds the elastic members for at least about 10 mm in the direction of stretch in a region adjacent the side edges of the front and back elastic belt regions, and a discrete patterned bonding applied to at least one of the inner sheet and the outer sheet with intervals in the transverse direction to intermittently bond the elastic member to at least one of the inner sheet and the outer sheet,
wherein the laminate is bonded by heat at the side edges to form side seams, the side seams existing no distant than about 20 mm from the side edges, and the remainder of the laminate is substantially free of heat bonds,
wherein the article has a Belt Elastic Bonding Percentage of less than about 25%, and an Individual Elastic Bonding Percentage of from about 10% to about 75%, preferably from about 20% to about 60%, according to the measurements herein.
While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as forming the present invention, it is believed that the invention will be better understood from the following description which is taken in conjunction with the accompanying drawings and which like designations are used to designate substantially identical elements, and in which:
As used herein, the following terms shall have the meaning specified thereafter:
“Wearable article” refers to articles of wear which may be in the form of pants, taped diapers, incontinent briefs, feminine hygiene garments, and the like. The “wearable article” may be so configured to also absorb and contain various exudates such as urine, feces, and menses discharged from the body. The “wearable article” may serve as an outer cover adaptable to be joined with a separable disposable absorbent insert for providing absorbent and containment function, such as those disclosed in PCT publication WO 2011/087503A.
“Pant” refers to disposable absorbent articles having a pre-formed waist and leg openings. A pant may be donned by inserting a wearer's legs into the leg openings and sliding the pant into position about the wearer's lower torso. Pants are also commonly referred to as “closed diapers”, “prefastened diapers”, “pull-on diapers”, “training pants” and “diaper-pants”.
“Longitudinal” refers to a direction running substantially perpendicular from a waist edge to an opposing waist edge of the article and generally parallel to the maximum linear dimension of the article.
“Transverse” refers to a direction perpendicular to the longitudinal direction.
“Proximal” and “distal” refer respectively to the position closer or farther relative to the longitudinal center of the article.
“Body-facing” and “garment-facing” refer respectively to the relative location of an element or a surface of an element or group of elements. “Body-facing” implies the element or surface is nearer to the wearer during wear than some other element or surface. “Garment-facing” implies the element or surface is more remote from the wearer during wear than some other element or surface (i.e., element or surface is proximate to the wearer's garments that may be worn over the disposable absorbent article).
“Disposed” refers to an element being located in a particular place or position.
“Joined” refers to configurations whereby an element is directly secured to another element by affixing the element directly to the other element and to configurations whereby an element is indirectly secured to another element by affixing the element to intermediate member(s) which in turn are affixed to the other element.
“Film” refers to a sheet-like material wherein the length and width of the material far exceed the thickness of the material. Typically, films have a thickness of about 0.5 mm or less.
“Water-permeable” and “water-impermeable” refer to the penetrability of materials in the context of the intended usage of disposable absorbent articles. Specifically, the term “water-permeable” refers to a layer or a layered structure having pores, openings, and/or interconnected void spaces that permit liquid water, urine, or synthetic urine to pass through its thickness in the absence of a forcing pressure. Conversely, the term “water-impermeable” refers to a layer or a layered structure through the thickness of which liquid water, urine, or synthetic urine cannot pass in the absence of a forcing pressure (aside from natural forces such as gravity). A layer or a layered structure that is water-impermeable according to this definition may be permeable to water vapor, i.e., may be “vapor-permeable”.
“Extendibility” and “extensible” mean that the width or length of the component in a relaxed state can be extended or increased.
“Elasticated” and “elasticized” mean that a component comprises at least a portion made of elastic material.
“Elongatable material”, “extensible material”, or “stretchable material” are used interchangeably and refer to a material that, upon application of a biasing force, can stretch to an elongated length of at least about 110% of its relaxed, original length (i.e. can stretch to 10 percent more than its original length), without rupture or breakage, and upon release of the applied force, shows little recovery, less than about 20% of its elongation without complete rupture or breakage as measured by EDANA method 20.2-89. In the event such an elongatable material recovers at least 40% of its elongation upon release of the applied force, the elongatable material will be considered to be “elastic” or “elastomeric.” For example, an elastic material that has an initial length of 100 mm can extend at least to 150 mm, and upon removal of the force retracts to a length of at least 130 mm (i.e., exhibiting a 40% recovery). In the event the material recovers less than 40% of its elongation upon release of the applied force, the elongatable material will be considered to be “substantially non-elastic” or “substantially non-elastomeric”. For example, an elongatable material that has an initial length of 100 mm can extend at least to 150 mm, and upon removal of the force retracts to a length of at least 145 mm (i.e., exhibiting a 10% recovery).
“Dimension”, “Length”, “Width”, “Pitch”, “Diameter”, “Aspect Ratio”, “Angle”, and “Area” of the article are all measured in a state wherein the article is extended to the Full Stretch Circumference W1 according to the “Whole Article Force Measurement” herein, and utilizing a ruler or a loupe, unless specified otherwise.
“Artwork” refers to a visual presentation to the naked eye, which is provided by printing or otherwise, and having a color. Printing includes various methods and apparatus well known to those skilled in the art such as lithographic, screen printing, flexographic, and gravure ink jet printing techniques.
“Color” or “Colored” as referred to herein includes any primary color except color white, i.e., black, red, blue, violet, orange, yellow, green, and indigo as well as any declination thereof or mixture thereof. The color white is defined as those colors having a L* value of at least 94, an a* value equal to 0±2, and a b* value equal to 0±2 according to the CIE L*a*b* color system.
The wearable article (20) may be a belt-type pant as in
The central chassis (38) may comprise a topsheet, a backsheet and an absorbent core (62) disposed between the topsheet and the backsheet, and further an outer cover layer (42) for covering the garment-facing side of the backsheet. The topsheet may be a water permeable substrate. The backsheet may be a water impermeable film. The outer cover layer (42) may be a nonwoven sheet. The central chassis (38) may contain an absorbent core (62) for absorbing and containing body exudates disposed on the central chassis (38), and an absorbent material non-existing region (61) surrounding the periphery of the absorbent core (62). The absorbent material non-existing region (61) may be made of the topsheet and/or the backsheet and/or the outer cover layer (42) and/or other parts configuring the central chassis (38). In the embodiment shown in
The absorbent core (62) may include an absorbent layer and an acquisition layer. The absorbent layer is the region wherein absorbent materials having a high retention capacity, such as superabsorbent polymers, are present. The absorbent layer may be substantially cellulose free. Superabsorbent polymers of the absorbent layer may be disposed between first and second layers of material immobilized by a fibrous layer of thermoplastic adhesive material. The first and second layers of materials may be nonwoven fibrous webs including synthetic fibers, such as mono-constituent fibers of PE, PET and PP, multiconstituent fibers such as side by side, core/sheath or island in the sea type fibers. Such synthetic fibers may be formed via a spunbonding process or a meltblowing process. The acquisition layer facilitates the acquisition and the distribution of body exudates and may be placed between the topsheet and the absorbent layer. The acquisition layer may include cellulosic fibers.
The absorbent layers may be disposed in plurality in the absorbent core (62). Some portions of the absorbent layers may be configured to have substantially no absorbent material to form a channel or a plurality of channels. Channels may be useful for allowing the absorbent core (62) to bend upon swelling with fluids, such that the absorbent article conforms to the wearer's body after swelling and prevent sagging of the article. The channels may also be formed in the acquisition layer, and may be configured to at least partly match the channels of the absorbent layer in the thickness direction.
The elastic belt (40) of the article of the present invention acts to dynamically create fitment forces and to distribute the forces dynamically generated during wear. The front and back elastic belts (84, 86) may be joined with each other only at the side edges (89) to form side seams (32), a waist opening and two leg openings. Each leg opening may be provided with elasticity around the perimeter of the leg opening. The elasticity around the leg opening may be provided by the combination of elasticity from the front belt (84), the back belt (86), and the central chassis (38).
The longitudinal length of the backsheet and the outer cover layer (42) may be the same, or may be varied. For example, the outer cover layer (42) may have a shorter length compared to that of the backsheet, such that the outer cover layer (42) is devoid where the central chassis (38) overlaps the elastic belt (40). By such configuration, the elastic belt may have better breathability. Further, such configuration may provide cost saving. The transverse width of the backsheet and the outer cover layer (42) may be the same, or may be varied. For example, the backsheet may have a shorter transverse width compared to that of the outer cover layer (42). By such configuration, the longitudinal side edges (48) of the crotch panel (56), which make part of the leg openings, may have better breathability. Further, such configuration may provide cost saving.
The front elastic belt (84) and back elastic belt (86) are configured to impart elasticity to the belt (40). Referring to
The laminate forming the front and back elastic belts (84, 86) have a structure wherein the inner sheet (94) and outer sheet (92) follow the gather shape of each other, and thus have higher percentage of area facing each other to be in direct contact. The laminate of the present invention thus has a relatively low Laminate Thickness, according to measurements herein, of no greater than about 3.5 mm, or no greater than about 3.0 mm, or no greater than about 2.5 mm. Further, in the laminate of the present invention, the inner sheet (92) has an inner sheet hydrophilicity, the outer sheet (92) has an outer sheet hydrophilicity, wherein the outer sheet hydrophilicity is greater than the inner sheet hydrophilicity. The relationship of the outer sheet (92) having higher hydrophilicity than the inner sheet (94) comprises situations where the inner sheet (94) is hydrophobic and the outer sheet (92) is hydrophilic; the inner and outer sheets are both hydrophobic wherein the outer sheet (92) has higher hydrophilicity (the inner sheet has higher hydrophobicity); and the inner and outer sheets are both hydrophilic wherein the outer sheet (92) has higher hydrophilicity. The inner and outer sheets may have a difference in contact angle of at least about 10 degrees, or a difference in contact angle of at least about 15 degrees, or a difference in contact angle of at least about 20 degrees. Without being bound by theory, it is believed that, by having the elastic members intermittently bonded and having a Laminate Thickness of no greater than about 3.5 mm, this increases the percentage of the body facing surface of the inner sheet (94) in direct contact with the body of the wearer, and further providing the inner sheet (94) relatively more hydrophobic, the outer sheet (92) relatively more hydrophilic, effective liquid removal and transport to the outer sheet is facilitated. Hence, the laminate enables fast and reliable transport of liquid, such as sweat, away from the body of the wearer and through the laminate thickness to outside the article.
The elastic belt region (40) may be closely associated with the function and quality of the article. Thus, materials for forming the elastic belt region (40), as well as the gathering profile of the elastic belt region, are carefully selected by the manufacturer for providing the desirables for the article. An undergarment kind of appearance and aesthetically pleasing regularity of gathering may be associated with high quality. Pleasant tactile sense such as flexibility and cushiony touch may also enhance perception of high quality. Stretchability for ease of application, fit for preventing sagging, comfort and softness, as well as breathability for skin health, may be associated with high function. Highly aesthetically pleasing gathers which intuitively communicate the functional benefits described above provide the favorable entire usage experience of the article by the user. The user may be the wearer or the caregiver.
The gathers of the present invention are continuous in the longitudinal direction, however, the direction of continuity may or may not completely match the longitudinal axis. The direction of gather is the direction in which the individual gathers are continuous, wherein the individual gathers are lined up with mountains and valleys repeating in the transverse direction. The Upper Gather Region (220) of the present invention may have a Directional Dispersion Value of no more than about 11 points, or no more than about 9 points, according to measurements herein. By Directional Dispersion Value, what is meant is the deviation from the direction of gather for each gathering, as analyzed by image analysis. The lower the Directional Dispersion Value, the less deviation of individual gathers from the direction of gather, and thus provides perception of aesthetically pleasing regularity.
The laminate having improved regularity of gathering of the present invention may be made by any method available in the art, and particularly by selecting a lofty nonwoven material of relatively high basis weight for either the outer sheet (92) or the inner sheet (94), and provide the other of the outer sheet (92) and inner sheet (94) to have a difference in basis weight. Further, the laminate having improved regularity of gathering may be made by bonding the elastic members (96) in an appropriate denier, longitudinal pitch, and force; to one or both of the inner sheet (94) and the outer sheet (92). The elastic member (96) may be intermittently bonded in the direction of stretch. The laminate of the present invention may be suitably provided by the methods below.
Referring to
What is meant by elastic bonding (230) herein is an adhesive bonding that bonds the elastic member (96) along the side edges (89) of the front and back elastic belts (84, 86). The elastic bonding (230) may be continuously applied to each elastic member (96) for a length of at least about 10 mm, or from about 10 mm to about 60 mm in the direction of stretch adjacent the side edges (89) of the front and back elastic belts (84, 86), including the length planned for side seaming. The elastic bonding (230) is to provide relatively strong bonding for the elastic member (96) and thus securely anchor the elastic member (96) within the laminate. The anchoring may be assisted by the side seaming A certain percentage, or a greater percentage, of the dimension of the elastic bonding (230) along the side edges (89) may be seamed. The elastic bonding may also be utilized for an effective process of deactivating a limited transverse dimension of the elastic member (96). Referring to
What is meant by discrete patterned bonding (234) herein is an adhesive bonding applied to at least one of the inner sheet (94) and the outer sheet (92) with intervals in the transverse direction for intermittently bonding the inner sheet (94) and the outer sheet (92). The discrete patterned bonding (234) may also bond the elastic member (96) to at least one of the inner sheet (94) and the outer sheet (92). The discrete patterned bonding (234) may only be provided to the outer sheet (92). The discrete patterned bonding (234) may only be provided to the inner sheet (94). Referring to
Referring to
Without being bound by theory, it is believed that by having less restriction for the inner sheet (94) and outer sheet (92) against the elastic members (96), this contributes in creating gathers of improved regularity, in that a significant amount of the inner and outer sheet materials (92, 94) existing between the discrete patterned bondings (234) are available for creating gathers continuous in the longitudinal direction. Without being bound by theory, it is also believed that, by having less restriction for the inner and outer sheet materials (92, 94) against the elastic members (96), this allows improved stretchability of the elastic members (96), which may provide ease of application.
Compared to elastic belts made only by elastic bonding (230) wherein all of the elastic members (96) are continuously bonded, the elastic belt (40) of the present invention may have a lower Stretch Circumference Force, according to the measurements herein. What is meant by Stretch Circumference Force is the loading force at a certain stretch level, which is believed to simulate initial stretch experience felt by the wearer or caregiver when inserting hands and stretch opening the article. Further, despite such relatively low Stretch Circumference Force, the elastic belt (40) of the present invention may maintain a suitable Fit Circumference Force, according to the measurements herein. What is meant by Fit Circumference Force is the unloading force at a certain stretch level, which is believed to simulate the force felt by the wearer while wearing the article. Accordingly, the article of the present invention has a Stretch Circumference Force of no more than about 6.5 N, or no more than about 6.0 N, and a Fit Circumference Force of at least about 3.0 N according to the measurements herein, wherein the ratio of the value of Stretch Circumference Force/Fit Circumference Force is less than about 1.8. A relatively low value for the ratio of Stretch Circumference Force/Fit Circumference Force means that there is less difference between the loading and unloading force felt by the wearer, thus providing the sensorial qualities similar to that of an undergarment. Without being bound by theory, it is also believed that, by having less restriction for the inner and outer sheet materials (92, 94) against the elastic members (96), this improves the breathability of the overall laminate, which may enhance skin health. Without being bound by theory, it is also believed that discrete patterned bonding (234) provides a configuration wherein a greater percentage of the inner and outer sheet materials (92, 94) are available for forming the outer surfaces of the laminate when the elastic belt (40) is contracted, while the elastic members (96) remain positioned inside the thickness of the laminate. As such, the laminate is provided with improved loft and thickness, thus imparting improved comfort and softness when worn. Further, without being bound by theory, in that there is a great percentage of the inner and outer sheet materials (92, 94) available for forming the outer surfaces of the laminate in high regularity when the elastic belt (40) is contracted, this provides the body facing surface of the elastic belt (40) to have higher stiffness in the longitudinal direction, thus contributing in improved fit for preventing sagging. Still further, in that the elastic members are less visible when the elastic belt (40) is contracted, this further enhances the aesthetically pleasing regularity of gathers.
In order to make available for gathering a significant amount of the inner and outer sheet materials (92, 94) between the discrete patterned bondings (234) in the transverse direction, VG1 may be from about 2 times to about 20 times, or from about 3.5 times to about 10 times of VG2. The bonding strength of the elastic bonding (230) and the discrete patterned bonding (234) may be the same or may be varied. The elastic bonding (230) and the discrete patterned bonding (234) may be provided by the same hot melt adhesive. Exemplary hot melt adhesives suitable for the present invention include tradenames H4376 and H2401 available from Bostik.
Referring to
Referring to
Referring to
The article of the present invention may have left and right elastic bondings, wherein in this length between the left and right elastic bondings (230, 230T), the elastic member may be attached or not attached by discrete patterned bonding (234). Without being bound by theory, it is believed that providing the elastic bonding (230) length as small as possible, this provides the elastic belt to have favorable soft feeling. By providing the bonding length as small as possible, this prevents aging of the adhesive on the elastic member (96). Aging of the adhesive may result in changing the intended force profile expected by the elastic member.
The article of the present invention may have a Belt Elastic Bonding Percentage of less than about 25%, or less than about 20%, or less than about 15%, according to the measurements herein. Namely, among all the elastic members (96) disposed on the front elastic belt region (84), less than about 25% of those elastic members are bonded to the laminate in active elasticity by a complete elastic bonding (230, 230T) along the length of active elasticity of the individual elastic member. When all of the elastic members are completely bonded by elastic bonding (230, 230T), then the Belt Elastic Bonding Percentage is 100%. For those laminates having a Belt Elastic Bonding Percentage of less than about 100%, those elastic members that are not completely bonded by elastic bonding (230, 230T) may further be subject of inspection of the percentage by which the specific elastic member is bonded by elastic bonding. The article of the present invention may have an Individual Elastic Bonding Percentage of from about 10% to about 75%, or from about 20% to about 60%, according to the measurements herein. Namely, among the individual elastic members which are not 100% bonded by elastic bonding (230, 230T), the percentage of each individual elastic member attached to the laminate by elastic bonding is inspected, and averaged. The lower the Individual Elastic Bonding Percentage, the less adhesive is used for bonding the elastic member to the laminate. Without being bound by theory, by providing the Individual Elastic Bonding Percentage in a given range, this provides secure bonding of the elastic strands to the laminate to endure further processing during manufacture as well as handling during usage, while also providing the overall laminate soft, and provide aesthetically pleasing regularity and continuity of gathers.
Referring to
Referring to
The front and back elastic belts (84, 86) may be made by running the continuous inner and outer sheet materials as well as the continuous elastic strands along the transverse axis of the article, and bonding them via the elastic bondings (230) and discrete patterned bondings (234). During manufacture, the continuous inner and outer sheet materials and continuous elastic strands may be transferred in the machine direction, wherein the machine direction of manufacture matches the transverse axis TX of the article. In such manufacturing process, the discrete patterned bondings (234) are provided continuous or discretely aligned in the cross machine direction and intermittently spaced apart by a pitch of VG1 in the machine direction of manufacture. The longitudinal pattern of discrete patterned bondings (234) may match the cross machine direction of manufacture, namely the longitudinal axis LX of the article, or may be slightly titled for better control of the process, particularly when the discrete patterned bonding (234) is provided by applying bonding on a rotating roller. The discrete patterned bonding (234) may be tilted with an angle from the cross machine direction of manufacture, namely the longitudinal axis LX of the article, by from about 0.1 to about 30 degrees in either clock-wise or counterclock-wise direction, or from about 0.1 to about 15 degrees in either clock-wise or counterclock-wise direction.
The tensile stress (N/m) of the entirety of the front and back elastic belts (84, 86), respectively, may be profiled in order to provide the functional benefits of the present invention, such as ease of stretch and application, while also maintaining certain force during wear, to prevent the article from sagging after loading. When the elasticity of the front and back elastic belts (84, 86) are provided by a plurality of elastic members (96) running in the transverse direction, the tensile stress may be adjusted by one or more of the following methods; 1) elongation rate of the elastic member (96); 2) density (dtex) of the elastic member (96); 3) longitudinal pitch of multiple elastic members (96); and 4) effective length of elasticity of the elastic member (96) in the transverse direction. By elongation, “0% elongation” is meant the original length of the elastic member. When a portion of an elastic member (96) is removed of its elasticity, the remainder of the intact elastic member capable of imparting elasticity is defined as the “effective length of elasticity of an elastic member”.
Referring to
Certain zones of the belt may be disposed of elastic bodies having a density of no more than about 500 dtex. Elastic bodies having a density of no more than about 500 dtex may be disposed on one or more of the front waist zone (102), the front distal tummy zone (104), or the front leg zone (108). Elastic bodies having a density of no more than about 500 dtex may be disposed on one or more of the back waist zone (102), the back proximal tummy zone (104), or the back leg zone (108). At least 50% of the elastic members on each of the front belt (84) and the back belt (86) may have a density of no more than about 500 dtex. Without being bound by theory, it is believed that elastic bodies of relatively low density impart an easy initial stretch experience when stretch opening the article (20), while maintaining a good fit during wear. Namely, use of such elastic bodies of relatively low density are advantageous in providing a controlled Stretch Circumference Force, while maintaining a certain Fit Circumference Force.
In the article of the present invention, the tensile stress of the front proximal tummy zone (106) may be provided higher than the tensile stress of any of the front waist zone (102), the front distal tummy zone (104), or the front leg zone (108). The tensile stress of the front proximal tummy zone (106) may be higher than the tensile stress of any other zone, either in the front or the back. The tensile stress of the back distal tummy zone (104) may be provided higher than any of the tensile stress of the back waist zone (102), the back proximal tummy zone (106), or the back leg zone (108). When comparing the 4 zones each of the front belt and the back belt, the tensile stress may be provided greatest in the order of: the front proximal tummy zone (106), followed by the back distal tummy zone (104). Without being bound by theory, such profiling of the tensile stress per zone is believed to provide the article of the present invention with a shaped elastic belt (40) that conforms well to a human body, particularly to a lower torso of a child of less than 36 months of age, and therefore provide good fit and comfort to the wearer, without compromise of sagging prevention or leakage prevention. Namely, the front proximal tummy zone (106) is subject to high tensile stress such that the article may be anchored against the wearer's trochanter, while leaving more area for the back proximal tummy zone (106) to accommodate the wearer's buttock. As long as the article is anchored securely at the trochanter, the Upper Gather Region (220) may be provided in relatively lower tensile stress. Without being bound by theory, it is believed that such relatively lower tensile stress contributes in providing the Upper Gather Region (220) with improved regularity of gathering, as well as soft fit.
For the belt-type pant, the longitudinal length LB of the back elastic belt (86) and the longitudinal length LF of the front elastic belt (84) may be provided the same, or the back elastic belt (86) may have a greater longitudinal length LB as in
In the present invention, at least one of the inner sheet (92) and the outer sheet (94) may further comprise a plurality of deformations wherein the deformations are aligned in the longitudinal direction and repeated in the transverse direction. Deformations may be apertures, slits, engravings, embossings, projections, or any other permanent deformation to the nonwoven material for making the inner sheet (92) and/or the outer sheet (94), so long as they are aligned in the longitudinal direction. For example, referring to
The deformation may be a continuous line extending in the longitudinal direction, or an array of discrete deformations aligned in the longitudinal direction and spaced apart from each other with a longitudinal pitch of DF2, wherein DF2 is not greater than DF1, as in
The deformation may be an aperture on the outer sheet, wherein the individual aperture may be in the shape of an oval, or polyhedron, while having an aspect ratio of no more than about 3, or no more than about 2.5. Referring to
Referring back to
The outer sheet (92) of the present invention may be a nonwoven having a basis weight of from about 10 gsm to about 55 gsm, or from about 10 gsm to about 35 gsm, and may have a fiber diameter of from about 0.8 dpf to about 6 dpf. The fiber diameter is described in denier per filament (dpf) used in the industry, which is grams/9,000 meters of length of fiber. The outer sheet (92) nonwoven may be made by processes such as spunbond, spunlace, carded or air-laid; and may comprise fibers and/or filaments made of polypropylene (PP), polyethylene (PE), polyethylene phthalate (PET), polylactic acid/polylactide (PLA) or conjugate fibers (such as PE/PET, PE/PP, PE/PLA) as well as natural fibers such as cotton or regenerated cellulosic fibers such as viscose or lyocell. The outer sheet (92) nonwoven may be a multilayer or composite structure combining nonwovens made by different processes and fibers such as combining spunbond and carded nonwovens. The outer sheet (92) nonwoven may be made by biodegradable material, or derived from renewable resources. Exemplary material for the outer sheet (92) include: air-through carded nonwoven having a thickness of at least about 50 μm, or at least about 80 μm, or at least about 200 μm. Such material may provide a soft lofty feeling to the garment-facing side. Suitable for the outer sheet (92) nonwoven of the present invention are air-through carded nonwoven material made of co-centric bicomponent fiber, crimping fiber made through core eccentric bicomponent filament or side by side bicomponent filament. Non-limiting examples of materials suitable for the outer sheet (92) nonwoven of the present invention include: 12-45 gsm air-through carded nonwoven substrate comprising PE/PET bi-component fibers, such as those available from Beijing Dayuan Nonwoven Fabric Co. Ltd. or Xiamen Yanjan New Material Co. Ltd., and 8-45 gsm spun melt nonwoven substrate comprising PP monofilament or PE/PP bi-component fibers, such as those available from Fibertex or Fitesa.
The inner sheet (94) of the present invention may be a nonwoven having a basis weight of from about 5 gsm to about 45 gsm, or from about 5 gsm to about 35 gsm. The inner sheet (94) nonwoven may have a fiber diameter of from about 0.5 dpf to about 4 dpf. The inner sheet (94) nonwoven may be made by processes such as spunbond, spunlace, carded or air-laid; and may comprise fibers and/or filaments made of polypropylene (PP), polyethylene (PE), polyethylene phthalate (PET), polylactic acid/polylactide (PLA) or conjugate fibers (such as PE/PET, PE/PP, PE/PLA) as well as natural fibers such as cotton or regenerated cellulosic fibers such as viscose or lyocell. The inner sheet (94) nonwoven may also be a multilayer or composite structure combining nonwovens made by different processes and fibers such as combining spunbond and carded nonwovens. The inner sheet (94) nonwoven may be made by biodegradable material, or derived from renewable resources. Non-limiting examples of materials suitable for the inner sheet (94) nonwoven of the present invention include: 12-30 gsm air-through carded nonwoven substrate made of PE/PET bi-component staple fiber, such as those available from Beijing Dayuan Nonwoven Fabric Co. Ltd. or Xiamen Yanjan New Material Co. Ltd., and 8-30 gsm spun melt nonwoven substrate comprising PP monofilament or PE/PP bi-component fibers, such as those available from Fibertex or Fitesa.
The basis weight of the outer sheet (92) and the inner sheet (94) may be adjusted such that the basis weight of the inner sheet (94) is not greater than the basis weight of the outer sheet (92). Thus, the outer sheet (92) may be provided with a soft lofty tactile sense which connotes high quality, while the inner sheet (94) may be kept thinner and conforming to the outer sheet (92), thus saving cost. Further, without being bound by theory, by providing the basis weight relationship as such, it is believed that skin sweating is effectively transported to the outer sheet (92) and outside the laminate, while preventing the transported sweat back to the inner sheet (94). The hydrophilicity/hydrophobicity of the outer sheet (92) and the inner sheet (94) may be adjusted such that the hydrophilicity of the outer sheet (92) is higher than that of the inner sheet (94). Without being bound by theory, it is believed that such gradient of hydrophilicity is advantageous in transporting skin sweat from the inner sheet (94) to the outer sheet (92) and outside the laminate. The inner sheet (94) nonwoven may be inherently hydrophobic. The inner sheet (94) nonwoven may be provided hydrophobicity by treating with hydrophobic melt additives into polymer resin in the fiber making process, or by applying hydrophobic additives after the nonwoven is formed. The outer sheet (92) nonwoven may inherently be hydrophobic, and thus provided relatively more hydrophilic than the inner sheet (94) by treating with hydrophilic melt additives into polymer resin in the fiber making process, or by applying hydrophilic additive after the nonwoven is formed.
As described above, the outer sheet (92) may be provided with apertures. Apertures may be made by female-male hot pin process, hole punching process, hydroentanglement process using water jets and a screen to create holes, and combinations thereof. The apertures may be made by creating a plurality of weakened locations by heat, pressure, or ultrasonic energy, followed by incremental stretching, causing said nonwoven web to rupture at the weakened locations such as described in U.S. Pat. No. 5,628,097. Such rupturing method may be particularly useful for nonwovens using spunbonded fibers and meltblown fibers. The apertures may be three-dimensional, non-homogenous, unaligned and forming a pattern as described in PCT Publication WO 2016/73712. The inner sheet (94) may also be provided with apertures for breathability. Apertures for the inner sheet (94) may be made in the same or different process, size, and density as the outer sheet (92). Providing apertures may alter the stiffness of the inner or outer sheet (92, 94). The stiffness of the outer sheet (92) in the longitudinal direction and the transverse direction may be adjusted to provide the desired longitudinally continuing gathers.
The front elastic belt (84) may comprise a waist opening gather zone along the waist opening for from about 5% to about 30%, or from about 10% to about 25%, of the longitudinal dimension of the front elastic belt LF, wherein the waist opening gather zone is in active elasticity and provided with an artwork. The waist opening gather zone may match with, or overlap with, the Upper Gather Region (220). The front elastic belt (84) may comprise a pair of leg opening gather zones along at least part of the leg openings for from about 5% to about 25%, or from about 5% to about 20%, of the longitudinal dimension of the front elastic belt LF, wherein the leg opening gather zones are in active elasticity and provided with an artwork. The artwork for the leg opening gather zones may be provided only along the leg opening, or spanned along the proximal edge (90) of the front elastic belt (84). The artwork for the leg opening gather zones may match the regions where the proximal edge of the front elastic belt (84) is in active elasticity, thus spanning slightly beyond the leg opening, while being discontinued in the regions matching the non-elastic region (221) of the front elastic belt (84). The longitudinal dimension of the leg opening gather zone may be from about 30% to about 80% of that of the waist opening gather zone.
The artwork of the waist opening gather zone and the artwork of the leg opening gather zones of the front elastic belt (84) may have at least a common color or a common shape. For example, the artwork may be a line or a plurality of lines spanning in the transverse direction. The lines may be straight lines or wavy lines. The waist opening gather zone and leg opening gather zone may both be provided with the gathers of low Directional Dispersion Value and/or high Continuity Value as explained above. By providing the waist opening gather zone and leg opening gather zone of the front elastic belt (84) in such dimension and appearance, the underwear like appearance of the overall article may be enhanced. Without being bound by theory, it is believed that the aesthetically pleasing gathers of the present invention having high regularity are advantageous in providing similarly regular appearance of the artwork superposing the gathers. The back elastic belt (86) may comprise a waist opening gather zone in active elasticity and provided with an artwork which matches the longitudinal dimension and appearance of those of the front elastic belt (84). The back elastic belt (86) may comprise a leg opening gather zone in active elasticity along the proximal edge (90) of the front elastic belt (84) and provided with an artwork which matches the longitudinal dimension and appearance of those of the front elastic belt (84). By providing both the front and back elastic belts (84, 86) with similar artwork, the underwear like appearance of the overall article may be enhanced.
The garment-facing side of the crotch region of the present article may be provided with visible deformations similar to those deformations provided for the outer sheet (92), as described above. By coordinating the visible deformations in the crotch region and the front and/or back elastic belt (84, 86), particularly the non-elastic region (221) of the front and/or back elastic belt, the integral undergarment like appearance of the article may be enhanced.
This measurement is for identifying 1) the percentage of elastic members on a laminate which are attached to the laminate solely by elastic bonding, defined as “Belt Elastic Bonding Percentage” and 2) the percentage of each individual elastic member attached to the laminate by elastic bonding, defined as “Individual Elastic Bonding Percentage”.
An article (20) sample is mounted on a rigid plastic plate which has an appropriate size which enables mounting the elastic belt (40) of the sample in a state stretched by 65% to 90% of its Full Stretch Circumference W1. For measurement of the article samples of Examples 2 and A-C, a rigid plastic plate having a dimension of 250 mm in the transverse direction and a thickness of 4 mm was used.
The sample mounted on the rigid plastic plate is placed on a non-reflective black background plate horizontally. A Canon camera (CanonEO2 6D Mark 2) with lens (EF 24-105 mm f/4L IS2 USM) or equivalent is placed directly vertically above the sample in a length of 1050 mm Two bar lights (Smart Vision Lights LHF 300 or equivalent) are placed 650 mm away from the sample in the transverse direction, 300 mm away from the sample in the vertical direction, wherein the surface of the light is faced in an angle of 45±6 degrees from the horizontal direction, and the longer dimension of the bar light is placed in parallel with the longitudinal axis of the sample. The focal length of the camera is set to 64 mm. The image acquisition settings are; ISO: 400, F: 5.0, exposure time: 1/160 seconds, and a resolution so that the acquired image has 11 pixel/mm.
Images are acquired for the front elastic belt and the back elastic belt.
A wearable article (20) is cut open by scissors along both side seams, the front elastic belt region (84) is identified, and then a specimen is excised. The specimen is a strip having side seams (32), the upper end edge matching the waist opening, and the lower end edge extending parallel to the waist opening at a longitudinal distance of at least 10 mm from the waist opening and about 3 mm from the nearest existing elastic strand towards the crotch. A point 100 mm distant in the lateral direction from just laterally inside one of the side edges is marked. The thus marked 100 mm point is the first side edge, and just inside the side edge from which the 100 mm was counted is the second side edge.
The portion of the specimen 100 mm wide is stretched until the first and second side edges reach a distance of 200 mm, i.e. 100% elongation from the original width. Referring to
The thickness measurements of laminate specimens are performed on the cross-section images generated under uniform surface lighting condition, using an optical microscope such as Keyence 3D Measurement System VR-3200 or equivalent. The magnification and focus is adjusted such that the cross-section side of the specimen is suitably enlarged for measurement. The cross-section side of the specimen is also oriented such that it is substantially aligned to the horizontal direction.
Analyses are performed using ImageJ software (version 1.49v or above, National Institutes of Health, USA) and calibrated against a ruler certified by NIST or equivalent. The image needs to be distance calibrated with an image of the ruler to give an image resolution, i.e. 42 pixels per mm. The microscope acquires a specimen image with a field of view size of at least 100 mm along the cross-section side.
Open a specimen image in ImageJ. Set the scale according to the image resolution. Randomly select five gather positions along the cross-section side and measure the local thickness that is the vertical distance between the peak (P) i.e. highest point and the valley (V) i.e. lowest point of the cross-section for one gather position. The thickness (T) of specimen is the arithmetic mean of the five readings of local thickness and recorded to the nearest 0.1 mm
Force is measured using an Electronic Tensile Tester with a computer interface such as the MTS Criterion C42 running TestWorks 4 Software (available from MTS SYSTEMS (CHINA) CO., LTD) or equivalent instrument. A load cell is selected so that force results for the samples tested will be between 10 and 90% of capacity of the load cell used. The instrument is calibrated according to the manufacturer's instructions. All testing is performed in a room maintained at 23±2° C. and 50±5% relative humidity.
The tensile tester is fitted with hanger-type sample holding fixtures (300) as shown in
Gauge Circumference=2×(H+D+πD/2)
where H is the vertical gap between the horizontal bar sections (302), and D is the outer diameter of the bar.
The instrument is set up to go through the following steps:
An article (20) sample is inserted onto the upper horizontal bar section (302) so that the bar passes through the waist opening and one leg opening of the article. The crosshead is raised until the specimen hangs above the lower bar and does not touch lower bar (302). The load cell is tared and the crosshead is lowered to enable the lower bar (302) to be inserted through the waist opening and other leg opening without stretching the article. The article is adjusted so that the longitudinal centerline LX of the article is in a horizontal plane halfway between the upper and lower bars (302). The center of the side portion in contact with the bar (302) is situated on the same vertical axis as the instrument load cell. The crosshead is raised slowly while the article is held in place by hand as necessary until the force is between 0.05 and 0.1N, while taking care not to add any unnecessary force. The gauge circumference at this point is the Initial Gauge Circumference. The test is initiated and the crosshead moves up at 254 mm/min until a force of 19.6N is attained, then the crosshead immediately returns to the Initial Gauge Circumference at the same speed. The maximum circumference at 19.6N and the force at 70% of the maximum circumference during the loading segment and unloading segment of the test are recorded.
The maximum circumference (mm) at 19.6N is defined as the Full Stretch Circumference W1. The Full Stretch Circumference (mm)×0.7 is defined as the 70% Stretch Circumference W2. The force (N) during the loading segment of the test at 70% Stretch Circumference is defined as the Stretch Circumference Force. The force (N) during the unloading segment of the test at 70% Stretch Circumference is defined as the Fit Circumference Force. Five samples are analyzed and their average are calculated and reported to the nearest 1 mm or 0.01N, respectively.
Examples 1-2 and A-C are obtained as such. Examples 2 and A-C were subject to the tests described below.
Size 4 (L-size) belt-type pant article having the configuration, elastic profile, and other properties in
Size 4 (L-size) belt-type pant article having the configuration, elastic profile, and other properties in
Size 4 (L-size) uni-body type pant article sold by the tradename of “Merries”. Lot No. 20190327 was used for Test 1 and 2, and Lot No. 20190422 was used for the other tests, all purchased in the China market.
Size 4 (L-size) uni-body type pant article sold by the tradename of “GooN Super Premium—Feather”. Lot Not. 20190306 was used for Test 1 and 2, and Lot No. 20181004 was used for the other tests, all purchased in the China market.
Size 4 (L-size) belt-type pant article sold by the tradename of “Teddy Bear More than thinner”. Lot No. 20190625 was used for Test 1 and 2, and Lot No. 20190424D was used for the other tests, all purchased in the China market.
The Stretch Circumference Force (SCF) and Fit Circumference Force (FCF) were measured according to the “Whole Article Force Measurement” method herein. The Belt Elastic Bonding Percentage (BEB) and Individual Elastic Bonding Percentage (IEB) were measured according to the measurement methods herein. The Directional Dispersion Values (DDV) were measured according to the “Directional Dispersion Value” measurements herein. The Laminate Thickness and Belt Elastic Bonding Percentage of the Examples were measured according to the measurements herein. Results of the aforementioned measurements are found in Table 2.
30 panelists who were caregivers of babies using Size 4 (L size) pant diapers and having a mixture of usage experience of major brands of similar price range used in the test were recruited. There were about equal number of caregivers of boy and girl babies in the age group of 25-36 years old. 15 finished product test samples were shown worn on a mannequin, and further provided to the panelist to touch and feel with their hands. All of the test samples were provided without any artwork. For Examples A, B, and C which were purchased from the market, the artwork was removed by removing the printed backsheet, and then reconstructing the sample replacing the backsheet with one that has no printing to make a finished product. Care was taken not to deteriorate the gather quality when reconstructing the sample. Each respondent was asked to fill in a questionnaire individually after observing and touching the test sample one by one. In the questionnaire, there were 7 values as found in Table 3, and each respondent was requested to rate the test samples against those values using the 5 ratings, which were scored as such: “Poor”=0, “Fair”=25, “Good”=50, “Very Good”=75, and “Excellent”=100. The scores were averaged.
Among 15 test samples tested, information for Examples 2, A, B, and C are extracted below in Table 3. Not all of the respondents rated all of the products, thus “Base Size” indicates the number of respondents.
According to the test results in Table 3, Example 2 which meets the parametric requirements of the present invention have statistically significantly higher overall acceptance than Examples A, B, and C, and is also statistically significantly better or superior in all of the other values. Example 2 of the present invention also has improved stretchability for ease of application, improved fit for preventing sagging, improved comfort and softness, and improved breathability for skin health.
The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm” Further, every numerical range given throughout this specification includes every narrower numerical range that falls within such broader numerical range.
Every document cited herein, including any cross referenced or related patent or application, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that 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 assigned to that term in this document shall govern.
While particular embodiments of the present invention have been illustrated and described, it would be obvious 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. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.
This application is a continuation, under 35 USC 120, of PCT Patent Application No. PCT/CN2020/104810, filed on Jul. 27, 2020, which is incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/CN2020/104810 | Jul 2020 | US |
| Child | 17526076 | US |
