Patent Application
20060293639
The present invention relates to disposable absorbent articles which are adapted to contain body exudates. More particularly, the present invention relates to disposable absorbent articles having a fastener located on a front waist region of the article.
Disposable garments, including disposable absorbent garments, have been known for decades. Disposable garments may include garments worn like underpants for children and adults, garments worn like training pants for toddlers and garments worn like diapers for infants. Disposable absorbent garments designed to absorb and contain bodily fluids may include adult/child incontinence garments, toddler training pants and infant diapers.
It is desirable for disposable garments to fit close to the body of the wearer for comfort and discretion. The disposable garment may include fasteners that assist with securing the position of the garment in use. For example, disposable garments may include adhesive or mechanical fasteners to assist with securing the garments around the waists of the users. During use, the fasteners undergo numerous stresses. As the user moves, by rolling, sitting, crawling and walking, the garments may deform, primarily in the front waist region as the angle between the user's legs and upper body increases and decreases. This movement and deformation may cause irritation to the user or may cause failure of the fastening system.
It is also desirable for disposable garments to be relatively easy to apply. Typically, disposable garments have outwardly extending tabs on the back portion of the garment. The tabs usually need to be unfolded before they are aligned with and fastened to a corresponding fastener located elsewhere on the garment. It may be difficult for some users to obtain optimum fit of a disposable garment if multiple steps are needed to ready the garment for fastening. One such step is the unfolding of tabs prior to fastening the garment.
Even though significant and numerous advancements have occurred in the materials and structural features available for the construction of disposable garments, there remains a need for garments which provide an optimum fit about the wearer and maintaining a pleasing appearance while being worn. Moreover, there remains a need for disposable absorbent articles which can be more easily secured about the waist of a wearer.
The present invention is directed to providing an absorbent article having a mechanical fastener disposed on the front waist region of the article, and that may connect with ear portions of the absorbent article. Varied peel and/or shear strengths may occur between the ear portions and the fastener assembly.
One aspect of the present invention concerns a disposable garment having a front waist region, a rear waist region and a crotch region which extends between and connects the front waist region and the rear waist region. The garment includes a body-facing surface, a garment-facing surface, and a fastener assembly. The fastener assembly has at least two attachment zones located on the garment-facing surface of the front waist region of the garment. The at least two attachment zones engage the body-facing surface at the back waist region at significantly different normalized peel or shear strengths.
In another aspect, the present invention concerns a disposable garment having a front waist region, a rear waist region and a crotch region which extends between and connects the front waist region and the rear waist region. The garment includes a body-facing surface, a garment-facing surface, and a fastener assembly. The fastener assembly includes two side attachment zones spaced apart and disposed on the garment-facing surface of the front waist region, and a middle attachment zone disposed on the garment-facing surface between the two side attachment zones. The middle attachment zone contains at least one first fastener material, and the side attachment zones contain at least one second fastener material. The side attachment zones engage the body-facing surface at significantly different normalized peel or shear strengths than the middle attachment zone.
In yet another aspect, the present invention concerns a disposable garment having a front waist region, a rear waist region and a crotch region which extends between and connects the front waist region and the rear waist region. The garment includes a body-facing surface, a garment-facing surface, and a fastener assembly. The fastener assembly includes two side attachment zones having a plurality of fastener components. The two side attachment zones are spaced apart and disposed on the garment facing surface of the front waist region. The fastener assembly further includes a middle attachment zone located between the two side attachment zones, the middle attachment zone containing at least one first fastener material and the side attachment zones containing at least one second fastener material. A pair of back ear portions extend from the rear waist region, and are configured so that they each engage at least a portion of the side attachment zones, and at least a portion of the middle attachment zone. The side attachment zones engage each of the pair of back ear portions at significantly different peel or shear strengths than the middle attachment zone.
Accordingly, the present invention provides a disposable garment having side attachment zones that when attached to the back ear portions of the garment, form side seams that primarily maintain the fit of the garment while in use. The middle attachment zone is useful for adjusting the fit of the garment and for maintaining a more garment-like appearance. One possible feature of the garment is its potential to have the back ear portions made from the same body facing material as the remainder of the garment, so that they may be attached to the fastener assembly without having to unfold tabs or the like.
It is understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide further explanation of the invention claimed. The accompanying drawings, which are incorporated in and constitute part of this specification, are included to illustrate and provide a further understanding of the article of the present invention. Together with the description, the drawings serve to explain the various aspects of the invention.
The present invention will be more fully understood and further advantages will become apparent when reference is made to the following detailed description of the invention and the accompanying drawings wherein like numerals represent like elements. The drawings are merely representative and are not intended to limit the scope of the appended claims.
The present disclosure of the invention will be expressed in terms of its various components, elements, constructions, configurations, arrangements and other features that may also be individually or collectively be referenced by the term, “aspect(s)” of the invention, or other similar terms. It is contemplated that the various forms of the disclosed invention may incorporate one or more of its various features and aspects, and that such features and aspects may be employed in any desired, operative combination thereof.
It should also be noted that, when employed in the present disclosure, the terms “comprises”, “comprising” and other derivatives from the root term “comprise” are intended to be open-ended terms that specify the presence of any stated features, elements, integers, steps, or components, and are not intended to preclude the presence or addition of one or more other features, elements, integers, steps, components, or groups thereof.
Within the context of this specification, each term or phrase below includes the following meaning or meanings:
“Attach” and its derivatives refer to the joining, adhering, connecting, bonding, sewing together, or the like, of two elements. Two elements will be considered to be attached together when they are integral with one another or attached directly to one another or indirectly to one another, such as when each is directly attached to intermediate elements. “Attach” and its derivatives include permanent, releasable, or refastenable attachment. In addition, the attachment can be completed either during the manufacturing process or by the end user.
“Bond” and its derivatives refer to the joining, adhering, connecting, attaching, sewing together, or the like, of two elements. Two elements will be considered to be bonded together when they are bonded directly to one another or indirectly to one another, such as when each is directly bonded to intermediate elements. “Bond” and its derivatives include permanent, releasable, or refastenable bonding.
“Connect” and its derivatives refer to the joining, adhering, bonding, attaching, sewing together, or the like, of two elements. Two elements will be considered to be connected together when they are connected directly to one another or indirectly to one another, such as when each is directly connected to intermediate elements. “Connect” and its derivatives include permanent, releasable, or refastenable connection. In addition, the connecting can be completed either during the manufacturing process or by the end user.
The terms “disposed on,” “disposed along,” or “disposed toward” and variations thereof are intended to mean that one element can be integral with another element, or that one element can be a separate structure bonded to or placed with or placed near another element.
“Elastic,” “elasticized,” “elasticity,” and “elastomeric” mean that property of a material or composite by virtue of which it tends to recover its original size and shape after removal of a force causing a deformation. Suitably, an elastic material or composite can be elongated by at least 25 percent (to 125 percent) of its relaxed length and will recover, upon-release of the applied force, at least 40 percent of its elongation. Desirably an elastic material or composite be capable of being elongated by at least 100 percent (to 200 percent), more desirably by at least 150 percent (to 250 percent), of its relaxed length and recover, upon release of an applied force, at least 50 percent of its elongation. “Hook and loop fasteners” refers to fastening means comprising a “hook” component and a complementary loop component. The term “hook” is used to designate a material having protruding or engaging elements. It should also be understood that the use of the term “hook” should be non-limiting in the sense that the engaging elements may comprise any shapes as are known in the art so long as they are adapted to engage a complementary fastener component or material characterized by loops or the like. “Layer” when used in the singular can have the dual meaning of a single element or a plurality of elements.
“Liquid impermeable,” when used in describing a layer or multi-layer laminate means that liquid, such as urine, will not pass through the layer or laminate, under ordinary use conditions, in a direction generally perpendicular to the plane of the layer or laminate at the point of liquid contact.
“Liquid permeable” refers to any material that is not liquid impermeable.
“Nonwoven” and “nonwoven web” refer to materials and webs of material that are formed without the aid of a textile weaving or knitting process. For example, nonwoven materials, fabrics or webs have been formed from many processes such as, for example, meltblowing processes, spunbonding processes, air laying processes, and bonded carded web processes.
“Stretchable” means that a material can be stretched, without breaking, by at least 25 percent (to 125 percent of its initial (unstretched) length) in at least one direction, suitably by at least 100 percent (to 200 percent of its initial length), desirably by at least 150 percent (to at least 250 percent of its initial length) and may or may not recover properties upon release of an applied force. Elastic materials and extensible materials are each stretchable materials.
“Superabsorbent material” refers to a water-swellable, water-insoluble organic or inorganic material capable, under the most favorable conditions, of absorbing at least about ten times its weight and, more desirably, at least about thirty times its weight in an aqueous solution containing about 0.9 weight percent sodium chloride.
These terms may be defined with additional language in the remaining portions of the specification.
The present invention is directed to providing disposable garments having an improved fastening system. Additionally, the present invention is directed to a garment having a unique combination of features that provide previously unrecognized and unexpected benefits. This detailed description of the present invention will include a description of a representative disposable garment including the various components of such garments. The description of the representative disposable garment will also include a description of many features encompassed by the present invention.
Representative Disposable Garment
The absorbent articles of the present invention will be described in terms of a disposable diaper article and in terms of a diaper pant that is adapted to be worn by infants about the lower torso. The representative disposable garments illustrated in
The diaper 20 defines a pair of laterally opposed side edges 30, a pair of longitudinally opposed waist edges 32, an interior surface 34 that is configured to contact the wearer, and an exterior surface 36 opposite the interior surface 34 that is configured to contact the wearer's clothing in use. The illustrated diaper 20 also includes a substantially liquid impermeable outer cover 42 and a liquid permeable bodyside liner 44 that can be connected to the outer cover 42 in a superposed relation. An absorbent core 28 is located between the outer cover 42 and the bodyside liner 44. The laterally opposed side edges 30 of the diaper 20 are generally defined by the side edges of the outer cover 42 that further define leg openings that may be curvilinear. The waist edges 32 of the diaper 20 are generally defined by the waist edges of the outer cover 42 and define a waist opening that is configured to encircle the waist of the wearer when worn. The absorbent core 28 is configured to contain and/or absorb body exudates discharged from the wearer. The diaper 20 may further include leg elastics 54, containment flaps 56 and waist elastics 58 as are known to those skilled in the art. It should be recognized that individual components of the diaper 20 may be optional depending upon the intended use of the diaper 20.
The diaper 20 may be of various suitable shapes. For example, in the unfastened configurations as illustrated in
The various components of the diaper 20 are integrally assembled together employing various types of suitable attachment means, such as adhesive, sonic and thermal bonds or combinations thereof. In the shown embodiments, for example, the outer cover 42 and bodyside liner 44 are assembled to each other and to the absorbent core 28 with adhesive, such as a hot melt, pressure-sensitive adhesive. The adhesive may be applied as a uniform continuous layer of adhesive, a patterned layer of adhesive, a sprayed pattern of adhesive, or an array of separate lines, swirls or dots of adhesive. Alternatively, the absorbent core 28 may be connected to the outer cover 42 using conventional fasteners such as buttons, hook and loop type fasteners, adhesive tape fasteners, and the like. The other components of the diaper 20 may be suitably connected together using similar means. Similarly, other diaper components, such as the elastic members 54 and 58 and the mechanical fasteners (described herein), may be assembled into the diaper 20 article by employing the above-identified attachment mechanisms. Desirably, the majority of the diaper components are assembled together using ultrasonic bonding techniques for reduced manufacturing cost.
The outer cover 42 of the diaper 20, as representatively illustrated in
The outer cover 42 may be formed of a woven or nonwoven fibrous web layer which has been totally or partially constructed or treated to impart a desired level of liquid impermeability to selected regions that are adjacent or proximate the absorbent core 28. Still further, the outer cover 42 may optionally be composed of a micro-porous “breathable” material which permits vapors to escape from the absorbent core 28 while still preventing liquid exudates from passing through the outer cover 42. For example, the outer cover 42 may include a vapor permeable non-woven facing layer laminated to a micro-porous film. Suitable “breathable” outer cover materials are described in U.S. Pat. No. 5,695,868 issued Dec. 9, 1997 to McCormack et al. and U.S. Pat. No. 5,843,056 issued Dec. 1, 1998 to Good et al., the descriptions of which are hereby incorporated by reference. Still further, the outer cover 42 may also be an elastomeric material such as a stretch-thermal laminate (STL), neck-bonded laminate (NBL), or stretch-bonded laminate (SBL) material. Methods of making such materials are well known to those skilled in the art and are described in U.S. Pat. No. 4,663,220 issued May 5, 1987 to Wisneski et al., U.S. Pat. No. 5,226,992 issued Jul. 13, 1993 to Morman, and European Patent Application No. EP 0 217 032 published on Apr. 8, 1987 in the names of Taylor et al., the disclosures of which are hereby incorporated by reference. The outer cover 42 can also be embossed or otherwise provided with a matte finish to provide a more aesthetically pleasing appearance.
In order to reduce the perception that the outer cover 42 feels damp or clammy, the diapers/diaper pants 20 of the invention may include a spacer or ventilation layer (not shown in Figures) between the garment-facing surface of the absorbent core 28 and the outer cover 42. The ventilation layer may include one or more nonwoven materials, for example a spunbond-meltblown-spunbond nonwoven material.
The representative absorbent articles of the invention include a bodyside liner 44 in superimposed relation to the outer cover 42. The bodyside liner 44, as representatively illustrated in
Various woven and nonwoven fabrics can be used for the bodyside liner 44. For example, the bodyside liner may be composed of a meltblown or spunbond web of polyolefin fibers. The bodyside liner 44 may also be a bonded-carded web composed of natural and/or synthetic fibers. The bodyside liner 44 may be composed of a substantially hydrophobic material, and the hydrophobic material may optionally be treated with a surfactant or otherwise processed to impart a desired level of wettability and hydrophilicity. In a particular embodiment of the present invention, the bodyside liner 44 is made from a nonwoven, spunbond, polypropylene fabric composed of fibers having a fiber diameter of about 21 to 23 microns formed into a web having a basis weight of about 20 grams per square meter and a density of about 0.13 grams per cubic centimeter. The fabric may be surface treated with about 0.3 weight percent of a surfactant, such as a surfactant commercially available from Hodgson Textile Chemicals, Inc. under the trade designation AHCOVEL Base N-62. The surfactant may be applied by any conventional means, such as spraying, printing, brush coating or similar techniques. The surfactant may be applied to the entire bodyside liner 44 or may be selectively applied to particular sections of the bodyside liner 44, such as the medial section along the longitudinal centerline of the diaper, to provide greater wettability of such sections. The bodyside liner 44 may further include a lotion or treatment applied thereto that is configured to be transferred to the wearer's skin. Suitable compositions for application to the bodyside liner 44 are described in U.S. Pat. No. 6,149,934 that issued to Krzysik et al. on Nov. 21, 2000.
The representative absorbent articles of the invention can include an absorbent core 28 disposed between the outer cover 42 and the bodyside liner 44. The absorbent core 28 of the diaper 20, as representatively illustrated in
The absorbent core 28 may have any of a number of shapes. For example, the absorbent core 28 may be rectangular, I-shaped, or T-shaped. It is generally preferred that the absorbent core 28 is narrower in the intermediate section than in the front or rear waist sections of the diaper 20. The absorbent core 28 may be provided by a single layer or, in the alternative, may be provided by multiple layers, all of which need not extend the entire length and width of the absorbent core 28. In a particular aspect of the invention, the absorbent core 28 can be generally T-shaped with the laterally extending cross-bar of the “T” generally corresponding to the front waist region 22 of the absorbent article for improved performance, especially for male infants.
The size and the absorbent capacity of absorbent core 28 should be compatible with the size of the intended wearer and the liquid loading imparted by the intended use of the absorbent article. Further, the size and the absorbent capacity of the absorbent core 28 can be varied to accommodate wearers ranging from infants through adults. In addition, it has been found that with the present invention, the densities and/or basis weights of the absorbent core 28 can be varied.
The high-absorbency material may be selected from natural, synthetic, and modified natural polymers and materials. The high-absorbency materials may be inorganic materials, such as silica gels, or organic compounds, such as crosslinked polymers. The term “crosslinked” refers to methods for effectively rendering normally water-soluble materials substantially water insoluble but swellable. Such methods include, for example, physical entanglement, crystalline domains, covalent bonds, ionic complexes and associations, hydrophilic associations such as hydrogen bonding, and hydrophobic associations or Van der Waals forces.
Examples of synthetic, polymeric, high-absorbency materials include the alkali metal and ammonium salts of poly(acrylic acid) and poly(methacrylic acid), poly(acrylamides), poly(vinyl ethers), maleic anhydride copolymers with vinyl ethers and alpha-olefins, poly(vinyl pyrrolidone), poly(vinyl morpholinone), poly(vinyl alcohol), and mixtures and copolymers thereof. Further polymers suitable for use in the absorbent core 28 include natural and modified natural polymers, such as hydrolyzed acrylonitrile-grafted starch, acrylic acid grafted starch, methyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, and the natural gums, such as alginates, xanthan gum, locust bean gum, and the like. Mixtures of natural and wholly or partially synthetic absorbent polymers can also be useful in the present invention.
The high absorbency material may be in any of a wide variety of geometric forms. As a general rule, it is preferred that the high absorbency material be in the form of discrete particles. However, the high absorbency material may also be in the form of fibers, flakes, rods, spheres, needles, or the like. In general, the high absorbency material is present in the absorbent core 28 in an amount of from about 5 to about 90 percent by weight, desirably in an amount of at least about 30 percent by weight, and even more desirably in an amount of at least about 50 percent by weight based on a total weight of the absorbent core 28. For example, in a particular aspect, the absorbent core 28 may include a laminate which includes at least about 50 percent by weight and desirably at least about 70 percent by weight of high-absorbency material overwrapped by a fibrous web or other suitable material for maintaining the high-absorbency material in a localized area.
Optionally, a substantially hydrophilic tissue or nonwoven wrapsheet (not illustrated) may be employed to help maintain the integrity of the structure of the absorbent core 28. The wrapsheet is typically placed about the absorbent core 28 over at least the two major facing surfaces thereof. The wrapsheet may be composed of an absorbent cellulosic material, such as creped wadding or a high wet-strength tissue. In one aspect of the invention, the wrapsheet may be configured to provide a wicking layer that helps to rapidly distribute liquid over the mass of absorbent fibers constituting the absorbent core 28.
Due to the thinness of absorbent core 28 and the high absorbency material within the absorbent core 28, the liquid uptake rates of the absorbent core 28, by itself, may be too low, or may not be adequately sustained over multiple insults of liquid into the absorbent core 28. To improve the overall liquid uptake and air exchange, the diaper 20 of the different aspects of the present invention may further include a porous, liquid-permeable layer of surge management material 53, as representatively illustrated in
Various woven and nonwoven fabrics can be used to construct the surge management layer 53. For example, the surge management layer 53 may be a layer composed of a meltblown or spunbond web of synthetic fibers, such as polyolefin fibers. The surge management layer 53 may also be a bonded-carded-web or an airlaid web composed of natural and synthetic fibers. The bonded-carded-web may, for example, be a thermally bonded web that is bonded using low melt binder fibers, powder or adhesive. The webs can optionally include a mixture of different fibers. The surge management layer 53 may be composed of a substantially hydrophobic material, and the hydrophobic material may optionally be treated with a surfactant or otherwise processed to impart a desired level of wettability and hydrophilicity. In a particular aspect, the surge management layer 53 includes a hydrophobic, nonwoven material having a basis weight of from about 30 to about 120 grams per square meter.
The absorbent articles of the invention can include additional components. For example, as representatively illustrated in
The diaper 20 of the different configurations of the present invention may further include elastics at the waist edges 32 and side edges 30 of the diaper 20 to further prevent leakage of body exudates and support the absorbent core 28. For example, as representatively illustrated in
Materials suitable for use as the leg elastics 54 and waist elastics 58 are well known to those skilled in the art. Exemplary of such materials are sheets or strands or ribbons-of a polymeric, elastomeric material that may be adhered to the outer cover 42 in a stretched position, or that may be attached to the outer cover 42 while the outer cover is pleated, such that elastic constrictive forces are imparted to the outer cover 42. The leg elastics 54 may also include such materials as polyurethane, synthetic and natural rubber. The waist elastics 58 may be formed by elastic strands attached to the outer cover 42 or they may be formed by attaching separate pieces of stretchable materials to the waist regions of the article. For example, the waist elastics 58 may include, a piece of stretch-bonded laminate material attached to the interior surface 34 of the article to form a waistband. Elasticity may be added or incorporated into the waist opening of absorbent articles utilizing a variety of known approaches.
Generally, the diaper pant chassis may be similar to the chassis described in U.S. patent application Ser. Nos. 10/750,253 filed Dec. 31, 2003, and Ser. No. 10/879,323 filed Jun. 29, 2004. Both applications are incorporated by reference to the extent that they do not conflict with the present application.
The absorbent articles of the present invention include a refastenable mechanical fastener assembly 60 as described below, that can operate in conjunction with one or more components which may extend laterally outward from the longitudinal sides of the article.
Each waist region 22, 24 may have a pair of ear portions extending therefrom. Thus, each waist region 22, 24 defines a center portion between lateral ear portions, namely, back ear portions 62 and front ear portions 64, respectively. The front ear portions 64 and the back ear portions 62 can be used to improve the fit of the absorbent article. For instance, the front ear portions 64 may provide additional coverage around the waist of the wearer and they may assist caregivers with positioning the front waist region 22 on the wearer of the article. The back ear portions 62 may also provide coverage around the waist of the wearer. More specifically, the back ear portions 62 may provide the bridging material between the back waist region 24 of the article and the front waist region 22 such that the back ear portions 62 form part of the article's waist opening and an upper edge of the article's leg openings.
Referring to
The back ear portions 62 may include or be comprised of material that is stretchable and extensible material, or material that is non-stretchable or non-extensible. Further, back ear portions 62 may be integral with the remaining portion of the diaper 20 as shown, or be a separate components that are attached to the diaper 20 (not shown). If back ear portions 62 and front ear portions 64 are formed integrally, they may be defined by the outer cover 42 and/or the bodyside liner 44 materials.
The back ear portions 62 may or may not have a separate mechanical fastener component attached thereto. Such components may be tab members (not shown) that extend outwardly in a substantially lateral direction from each back ear portion 62. Like the ears, the tabs may be integral, attached, stretchable and/or extensible, or neither stretchable nor extensible.
Back ear portions 62 may include a fastener material that is attached to the inner ear surface 63, which does not extend outwardly from the ear portion 62 in a plane that extends in the longitudinal direction 38 and lateral direction 40. Suitably, the back ear portions 62 do not include separate tabs or mechanical fastener components, and instead have a body facing surface 63 that is capable of directly engaging the mechanical fastener assembly 60. The advantage this provides is that the wearer does not have to purposefully match up a fastener on the back ear portion 62 with the mechanical fastener assembly 60. For instance, caretakers of children do not have to search for a tab or back ear fastening component when changing a diaper, and an adult with limited mobility or sight does not have to feel or look for a tab or back ear fastening component when applying an incontinence garment.
Desirably, back ear portions 62 may be comprised of a material that can engage a mechanical fastener assembly 60 located on the front waist region 22 (see
The shape and size of the front and back ear portions 62, 64 may vary from what is shown by way of example in the Figures. Further, when the product form of the absorbent article is a training pant or a swim pant, the back ear portions 62 and the front ear portions 64 are understood to include the side panels that are attached to the longitudinal sides 30 of the article and also are attached to each other to form side seams of the article. Typically, the side panels of training pants and swim pants are made from stretchable materials. The side panels' ability to stretch allows these products to be pulled on the wearer like underpants.
The mechanical fastener assembly 60 releasably engages the back ear portions 62 of the diaper 20. Generally, fastener assembly 60 is an elongated member defined by a pair of outer regions 75 that are separated by a middle portion 80. The outermost lateral edges of each outer region 75 are defined by distal edges 70. In the longitudinal direction 38, the longitudinal length of the distal edge 70 may be greater than the longitudinal length of the middle portion 80. Suitably, the length of the middle portion 80 may gradually increase in length from an inward edge 82 until it reaches the length of distal edge 70. Likewise, the length of the middle portion 80 may gradually increase in length from an outward edge 83 until it reaches the length of distal edge 70. As described herein, the fastener assembly 60 may have various configurations, and have single or multiple components.
One embodiment of the fastener assembly 60 is illustrated in
Desirably, in the longitudinal direction 38, the length of each distal edge 70 is such that a side seam 76 is formed when the diaper 20 is in a fastened position. For any of the embodiments described herein, side seam 76 is defined by the bond between the front waist region 22 and the back waist region 24. Side seam 76 is the primary fastening or bond that fits the diaper 20 to the wearer's body. Side seam 76 may coincide with the wearer's general hip region, and may either be positioned like a seam found in a pair of traditional cloth underpants, or be located more forward or backward than a seam found in a pair of traditional cloth underpants.
Still referring to
Alternatively, as shown in
Though shown as being comprised of seven separate components, fastener assembly 60a may be comprised of more or less number of components. In addition, the shape of each separate component 184 and 185 need not be rectangular as shown, but could consist of a series of dots, ovals, lines (either straight or curved), decorative shapes, and the like.
Overall, the general shape of fastener assembly 60a may be the same as the fastener assembly 60 shown in
The width of the various components as measured in lateral direction 40 may vary depending on the fastener material properties and the size range the diaper is intended to cover. In particular, the width of center component 185 may be such that the back ear portion 62 can be fastened thereto until the wearer is in need of a size change. Thus, the back ear portions 62 may overlap, or may cover about 50 percent of the width of the center component 185 to as little as about 15 percent of the center component 185. Further, one ear portion may cover a significantly larger area of center component than the other ear portion, for example a 90/10 ratio of coverage could be possible. The width of components 184 may vary from component to component or be equivalent. Suitably, the width of components 184 is about 10 mm to about 30 mm; more suitably about 5 mm to about 20 mm, and even more suitably about 3 mm to about 10 mm.
Referring now to
Outer components 90 define side seam 76 when the diaper 20 is in a fastened condition. Outer components may be substantially aligned with the longitudinal direction 38, whereas central component may be substantially aligned with the lateral direction 40.
As with the previous embodiment, the shape of each separate component 90, 92 need not be rectangular as shown, but could consist of a series of dots, ovals, triangles, lines (either straight or curved), decorative shapes, and the like. Because there are only three components in this particular embodiment, fastener assembly 60b will generally have an overall I-shape wherein the distal edges 70 are greater in length in the longitudinal direction 38 than the middle portion 80. Suitably, it is desirable that the middle portion 80 have a length of about 1.2 cm to about 7.6 cm, (0.5 inches to about 3 inches) and the distal ends 70 have a length of about 3.8-cm to about 20.3 cm, (1.5 inches to about 8 inches). More suitably, it is desirable that the middle portion 80 have a length of about 2.5 cm to about 5.1 cm (1 inches to about 2 inches) and the distal ends 70 have a length of about 5.1 cm to about 15.2 cm, (2 inches to about 6 inches). Even suitably, it is desirable that the middle portion 80 have a length of about 3.2 cm to about 3.8 cm, (1.25 inches to about 1.5 inches) and the distal ends 70 have a length of about(6.4 cm to about 12.7 cm, (2.5 inches to about 5 inches
The width of the various components may vary depending on the fastener material properties and the size range the diaper is intended to cover. In particular, the width of center component 92 may be such that the back ear portion 62 can be fastened thereto until the wearer is in need of a size change. Thus, the back ear portion 62 may cover about 50 percent of the width of the center component 92 or possibly overlap as described above for the previous embodiment. Or, back ear portion 62 may each cover as little as about 15 percent of the center component 92. Suitably, the width of outer component may be about 5 mm to about 25 mm; more suitably about 10 mm to about 20 mm, and even more suitably about 12 mm to about 15 mm.
Regardless of the embodiment of the fastener assembly as shown in
Peel and shear strengths between fastener assembly component and back ear portion may be measured and the resulting strengths “normalized” to account for fastener surface area, aspect ratio, and/or length. Using test techniques as described herein for hook-and-loop fasteners (or comparable techniques for non hook-and-loop fasteners), the normalized primary peel strength may be greater than the normalized secondary peel strength by as much as about 10 to about 200 percent, more suitably by as much as about 10 to about 75 percent, and even more suitably by as much as about 15 to about 50 percent. The primary shear strength may be greater than the secondary shear strength by as much as about 10 to about 200 percent, and more suitably by as much as about 20 to about 150 percent, and even more suitably by as much as about 30 to about 100 percent.
The peel strength of a fastener is directly proportional to the length of the fastener, wherein thle fastener length is measured in a direction perpendicular to the peel force. For example, if the length of a primary fastener is 7.6 cm (3 inches) and the length of a secondary fastener made from the same material 2.5 cm is (1.0 inch), the force required to peel the primary fastener from a material would be about 3 times the force required to peel the secondary fastener from the same material.
The shear strength of a fastener is related the surface area and aspect ratio of the contacting portion of the fastening assembly and back ear portion. When the surface area of the primary fastener is greater than the surface area of the secondary fastener, the primary fastener will exhibit greater shear strength than the secondary fastener when the aspect ratios and materials are equivalent. For example, a square fastening component with an area of 5.08 cm square (2 inch square) may have about twice the shear strength of a square fastening component with an area of 2.54 cm square (1.0 inch square). If the area is held constant, and the aspect ratio is such that the same fastening material is rectangular, for example 2:1, it may exhibit a lower or higher shear strength depending on how the rectangular fastener is oriented with respect to an applied shear force.
Peel Strength Test
This procedure is a tensile bench test to measure the peel force required to. separate a mechanical fastening system that joins two materials. The peel force of separation is measured by determining load values as the two materials are pulled apart perpendicular to their plane of contact. The direction of removal (peel), in this application, is that direction in which the fastener material would generally be removed from a substrate when the product is in use. Peel strength is normalized by dividing by the contact area resulting in a force per area.
Equipment
1. Tensile tester capable of obtaining a peak load and equipped with an appropriate load cell. A suitable tensile testing system is a Sintech Tensile Tester, commercially available from MTS Sintech, Research Triangle Park, N.C., under the trade designation instron Model 4201 Tensile Tester with Sintech QAD (Quality Assurance Department) Software.
2. Software commercially obtained from MTS Sintech under the trade designation Sintech Testworks®.
3. Pnuematic-action grips commercially available from Instron Corporation, Canton, Mass., under the trade designation “Instron Model 2712-004.”
4. 1 by 4 inch grip faces, serrated, commercially available from Instron Corporation, Canton, Mass.
5. Test facility having a temperature of 23±1° C., and a relative humidity of 50±2 percent.
Test Procedure
1. A sample to be tested is conditioned in the test facility for at least 4 hours prior to testing.
2. The load cell is calibrated and the software loaded.
3. The grips are installed on the tensile tester with the jaws closed.
4. The test condition for the tensile tester is set as follows:
5. The weight of the clamp is tared out.
6. The ear portion on the back waist region of the article is inserted into the upper jaw such that the edge of the grip face is flush with the inner edge of the fastener material.
7. The front waist region of the article is inserted into the lower jaw such that the inner surface of the back waist region and the outer surface of the front waist region form a 180° angle. The lower jaw is closed.
8. The crosshead is started in motion.
9. The peak load of failure is recorded. It is intended that the mode of failure is that the back waist region of the diaper separates from the front waist region of the diaper.
Shear Strength Test
This procedure is a tensile bench test to measure the shear force required to separate a mechanical fastening system that joins two materials. The shear force of separation is measured by determining load values as the two materials are pulled apart parallel to their plane of contact. The shear strength test values are an indication of how well the mechanical fastening system stays engaged against in-plane shear force. The sample is pulled in the tensile tester until the sample pulls apart. Shear strength is the peak load result. Shear strength is normalized by dividing by the contact area resulting in a force per area.
Equipment
1. Tensile tester capable of obtaining a peak load and equipped with an appropriate load cell. A suitable tensile testing system is a Sintech Tensile Tester, commercially available from MTS Sintech, Research Triangle Park, N.C., under the trade designation Instron Model 4201 Tensile Tester with Sintech QAD (Quality Assurance Department) Software.
2. Software commercially obtained from MTS Sintech under the trade designation Sintech Testworks®.
3. Pnuematic-action grips commercially available from Instron Corporation, Canton, Mass., under the trade designation “Instron Model 2712-004.”
4. 1 by 4 inch grip faces, serrated, commercially available from Instron Corporation, Canton, Mass.
5. Test facility having a temperature of 23±1° C., and a relative humidity of 50±2 percent.
Test Procedure
1. A sample to be tested is conditioned in the test facility for at least 4 hours prior to testing.
2. The load cell is calibrated and the software loaded.
3. The grips are installed on the tensile tester with the jaws closed.
4. The test condition for the tensile tester is set as follows:
5. The weight of the clamp is tared out.
6. The back ear portion of the article is inserted into the upper jaw such that the edge of the grip face is flush with the inner edge of the hook material.
7. The front waist region of the article is inserted into the lower jaw such that the inner surface of the back waist region and the inner surface of the front waist region are facing the same direction and are parallel to one another. The lower jaw is closed.
8. The crosshead is started in motion.
9. The peak load of failure is recorded. It is intended that the mode of failure is that the back waist region of the article separates from the front waist region of the article.
On the diaper 20, peel and shear strengths may be varied by (a) using different fastener materials along the lateral direction 40 of the fastener assembly 60-60b; (b) modifying the surface of the fastener assembly 60-60b along the lateral direction 40, by adding materials thereto, or by spraying, embossing, melting, deforming or the like; (c) modifying the inner ear surface 63 of the back ear portion, either by adding materials thereto, or by spraying, embossing, melting, deforming or the like; or (d) a combination of the above. Fastener assembly 60-60b and optional fastener materials added to inner ear surface 63 can include a variety of materials and surfaces known for mechanical engagement such as buttons, pins, snaps, adhesive tape fasteners, cohesives, mushroom-and-loop fasteners, and hook-and-loop fasteners, or the like. “Hooks” may be hook-like or post-like. Another possible fastener material includes reticulated foam, for example, FOAMEX Z6SCLY, manufactured by Foamex Intemational Inc., Linwood, Pa. Desirably, the fastener assembly 60-60b is comprised of mechanical fastener materials that include components or members which protrude outwardly from the garment facing surface of diaper 20, e.g. an array of hooks or posts. Such protruding fastener materials may directly engage the inner ear surface 63.
Several examples of how connections having varying peel and shear strength can be realized are presented. However, it is not intended that the present invention be limited to these few examples. First, in the bow-shaped embodiment of
Rather than having more than one material in each attachment zone, there may be only a single first material and a single second material. The first and second materials may be integrally connected (e.g. cut from a single sheet) or pieced together and either attached together, abutted or positioned in close proximity. Desirably, the first and second materials may be a hook material that has been modified in either the middle portion or the outer regions to make the peel and or shear values differ when the back ear portions 62 are attached thereto. For example, an adhesive material may be added to the middle portion 80 to increase the peel strength.
The second material(s), in combination, have different peel or shear characteristics from the first material(s). In combination, the second material(s) in the side attachment zones have different peel or shear characteristics from the first material(s) in the middle attachment zones. It should be understood that the materials in the two side attachments zones may be different from each other in that they are not comprised of the same materials, or they may have the same peel and/or shear properties when attached to a common material. Of course, rather than having more than one material in each attachment zone, there may be only a single first material and a single second material. The inner surface 63 of the back ear portion 62 may be made from the same material as the bodyside liner 44.
In the third example as seen in
In an alternative embodiment (not shown), the diaper 20 may have the back ear portion 62 located where the current front ear portion 64 is located, and the front ear portion 64 located where the back ear portion 62 is located, and the mechanical fastener assembly 60-60b may be disposed on the back surface waist region 24 instead of the front waist region 22 of the diaper 20. In addition, separate tab members may extend form the back ear portion 62 (not shown).
In operation, the diaper 20 of the present invention may be pre-fastened so that it may be applied and removed as either a diaper or a pant. If the diaper 20 is applied in diaper fashion, the wearer or caretaker aligns the pant about the body and fastens the diaper 20 by overlapping and then attaching the inner surface 63 of back ear portions 62 to the fastener assembly 60. If there is no addition or modification or the inner surface 63, there is no need for-the wearer/caretaker to align any particular area if the inner surface 63 with the fastener assembly,60. If there is an addition or modification to the inner surface 63, it is desirable that the area of the addition or modification be sized such that the wearer/caretaker does not need to take additional effort to align these areas with portions of the fastener assembly 60. Once the side seam 76 is formed by attaching the proximal region 96 of the back ear portion to the fastener assembly, distal regions 98 may be repositioned to adjust the fit and/or appearance of the diaper 20.
One of skill in the art will readily appreciate that the various fastener assemblies and ears described herein may be combined to arrive at a number of configurations not illustrated herein, yet quite suitable for use in fastening diapers and or pants. Having described the invention in rather full detail, it will be readily apparent that various changes and modifications can be made without departing from the spirit of the invention. All of such changes and modifications are contemplated as being within the scope of the invention as defined by the appended claims and any equivalents thereto.
