Patent Application
20180177643
Absorbent articles such as diapers, training pants, incontinence products, feminine hygiene products as well as health care related products such as bandages and other wound dressings have a common goal of rapidly absorbing discharged body fluids such as blood, menses, urine and bowel movements. Typically such products will have a body contacting side and surface which is near or in contact with the wearer's skin, some type of absorbent core and a back sheet or outercover that will prevent the retained fluids from exiting the product and possibly soiling the surrounding areas including the wearer's clothing.
Thus, it is desirable for such products to rapidly take in fluids, pass them to subjacent layers in the product and provide air circulation adjacent the wearer's skin to promote skin wellness. Air circulation allows drying of the skin to prevent skin irritation such as diaper rash in the case of diapers, training pants and incontinence devices. Air circulation also provides increased comfort by allowing the body contacting material, often referred to as a top sheet or liner, to dry out. In addition, comfort and dryness can be further enhanced by minimizing the amount of the liner material that is in direct contact with the skin. This also facilitates a reduction in what is called “rewet” which is the backflow of fluid from the absorbent core onto the liner. As these are desirable attributes for such products, a number of materials and products have attempted to provide these results.
Dryness, softness and breathability are key attributes in personal care absorbent articles. Currently most body side liner materials are very planar and two-dimensional, even when laminates and other multi-layer structures are employed. While aperturing and embossing are employed with such structures, there is still a need for laminates which provide rapid fluid intake, minimal body contact and reduced rewet. In addition, it is desirable for such materials, even if more three-dimensional in design, to be able to maintain a more three-dimensional nature even after subjected to compressive forces. While the foregoing are examples of attempts to provide materials with the desired fluid handling properties, there is still a need for improved materials in this regard. The present invention is directed to a laminate which can be used in this regard in conjunction with personal care absorbent articles including, but not limited to, diapers, training pants, incontinence garments, feminine hygiene products such as sanitary napkins and panty liners as well as other absorbent products including bandages, wound dressings and various types of wiping products.
A process is disclosed for forming a laminate including a fibrous nonwoven web first layer and a second layer which involves providing a first roll having a first roll surface and a second roll having a second roll surface. At least one of the first roll and the second roll has a first plurality of embossing pins extending outwardly from the respective first roll surface or second roll surface. In addition, at least one of the first roll and the second roll can also have a first plurality of aperturing pins extending outwardly from the respective first roll surface or second roll surface so that collectively the first roll and the second roll can be used to form a first plurality of embossments and a first plurality of apertures. For example, the first roll can be fitted with a first plurality of embossing pins and the second roll can be fitted with a first plurality of aperturing pins. Alternatively, the first roll can contain both the first plurality of embossing pins and the first plurality of aperturing pins. Still further, the first plurality of embossing pins can be apportioned between the first roll and the second roll as can the first plurality of aperturing pins.
The first roll surface of the first roll and the second roll surface of the second roll are positioned in mating relationship to form a nip between the first roll surface of the first roll and the second roll surface of the second roll with the first plurality of embossing pins and the first plurality of aperturing pins defining a first roll embossing region in the nip between the first roll and the second roll. The first roll further defines a first roll merging region, a first roll bonding region and a first roll take-off region. A bonding apparatus is positioned adjacent the first roll surface of the first roll in the first roll bonding region and each of the first roll and the second roll are rotated in a counter-rotating relationship with respect to one another.
To utilize the process there is provided a first layer and a second layer. The first layer is formed of a fibrous nonwoven web having a first layer top surface and a first layer bottom surface separated by a first layer thickness. The second layer has a second layer upper surface and a second layer lower surface separated by a second layer thickness.
In use, the first layer top surface of the first layer is fed into the nip adjacent the first roll surface of the first roll to simultaneously form a first plurality of embossments and a first plurality of apertures in the first layer in the first roll embossing region of the first roll. The second layer upper surface of the second layer is then fed onto the first layer bottom surface of the first layer in the first roll merging region of the first roll with the second layer upper surface of the second layer contacting the first plurality of embossments in the first layer.
In the next portion of the process, a bonding apparatus located in the first roll bonding region is used to bond the second layer upper surface of the second layer to the first plurality of embossments of the first layer in the first roll bonding region of the first roll to form the laminate with an air gap located between the first layer bottom surface of the first layer and the second layer upper surface of the second layer. Once the laminate is formed, it is removed from the first roll in the first roll take-off region of the first roll.
If desired, the process can further include a first plurality of embossing recesses located on the other one of the first roll and the second roll that does not have the first plurality of embossing pins such that the first plurality of embossing pins can mate with the first plurality of embossing recesses located in the other roll.
If desired, in addition, the process can further include a first plurality of aperturing recesses located on the other one of the first roll and the second roll that does not have the first plurality of aperturing pins such that the first plurality of aperturing pins can mate with the first plurality of aperturing recesses located in the other roll. Still further, the embossing pins and recesses as well as the aperturing pins and recesses can be apportioned between the two rolls.
An adaptation of the above process is also disclosed hereinfor forming a laminate including a fibrous nonwoven web first layer and a second layer. The process involves providing a first roll having a first plurality of embossing pins and a first plurality of aperturing pins, each extending outwardly from a first roll surface on the first roll for forming a first plurality of embossments and a first plurality of apertures.
The process involves providing a second roll having a first plurality of embossing recesses and a first plurality of aperturing recesses located in a second roll surface of the second roll. The first plurality of embossing pins mate with the first plurality of embossing recesses and the first plurality of aperturing pins mate with the first plurality of aperturing recesses. The first roll surface of the first roll and the second roll surface of the second roll are positioned in mating relationship with one another to form a nip between the first roll surface of the first roll and the second roll surface of the second roll with the first plurality of embossing pins of the first roll mating with the first plurality of embossing recesses of the second roll and the first plurality of aperturing pins of the first roll mating with the first plurality of aperturing recesses of the second roll.
The nip defines a first roll embossing region on the first roll with the first roll further defining a first roll merging region, a first roll bonding region and a first roll take-off region. A bonding apparatus is positioned adjacent the first roll surface of the first roll in the first roll bonding region. Each of the first roll and the second roll are rotated in a counter-rotating relationship with respect to one another.
To utilize the process, there is provided a first layer and a second layer. The first layer is formed of a fibrous nonwoven web having a first layer top surface and a first layer bottom surface separated by a first layer thickness. The second layer has a second layer upper surface and a second layer lower surface separated by a second layer thickness.
In use, the first layer top surface of the first layer is fed into the nip adjacent the first roll surface of the first roll to simultaneously form a first plurality of embossments and a first plurality of apertures in the first layer in the first roll embossing region of the first roll. The second layer upper surface of the second layer is then fed onto the first layer bottom surface of the first layer in the first roll merging region of the first roll with the second layer upper surface of the second layer contacting the first plurality of embossments in the first layer.
In the next portion of the process a bonding apparatus located in the first roll bonding region is used to bond the second layer upper surface of the second layer to the first plurality of embossments of the first layer within the first roll bonding region of the first roll to form the laminate with an air gap located between the first layer bottom surface of the first layer and the second layer upper surface of the second layer. Once the laminate is formed, it is removed from the first roll in the first roll take-off region of the first roll.
If desired, the process can further include the step of aperturing the second layer prior to feeding the second layer into the first roll merging region of the first roll.
If desired, the bonding step of the process can include ultrasonically bonding the first layer to the second layer or it can use heat and pressure to bond the first layer to the second layer.
If desired the bonding step can cause apertures to be formed in an area where the second layer upper surface of the second layer is bonded to at least a portion of the first plurality of embossments in the first layer.
The result of the process is the formation of a laminate. If desired, an absorbent article can be formed including the laminate formed by the aforementioned process.
Also disclosed is an absorbent article comprising a liquid permeable top sheet and a liquid impermeable outer cover with an absorbent core located between the topsheet and the outer cover with the topsheet formed by the aforementioned process.
The laminate can include a first fibrous nonwoven layer and a second layer joined to each other at a plurality of embossment bond points. The first layer has a first layer top surface and a first layer bottom surface which define a first layer thickness therebetween. The first layer defines a plurality of first layer apertures therein at least a portion of which extend from the first layer top surface to the first layer bottom surface to create passageways therebetween. The second layer comprises a second layer upper surface and a second layer lower surface which define a second layer thickness therebetween. The first layer bottom surface of the first layer is in a spaced apart relationship to the second layer upper surface of the second layer. The first layer includes a plurality of first layer embossments, at least a portion of which begin in the first layer top surface and define embossment openings. The first layer embossments depend downwardly with embossment side walls and embossment bottoms. The embossment bottoms are located in the first layer bottom surface of the first layer. At least a portion of the embossment bottoms of the first layer embossments are bonded to the second layer upper surface of the second layer by way of the embossment bond points whereby an air gap is formed between the first layer bottom surface of the first layer and the second layer upper surface of the second layer in an area between the embossment bond points.
If desired, the second layer of the laminate can define a plurality of spaced-apart second layer apertures therein at least a portion of which extend from the second layer upper surface of the second layer to the second layer lower surface of the second layer to create liquid passageways therebetween. Additionally, if desired, at least a portion of the plurality of first layer embossment side walls can define apertures therein.
In some embodiments, the second layer of the laminate can be a fibrous nonwoven web or, alternatively, an apertured film.
Applications of the present invention include an absorbent article including a liquid permeable top sheet and a liquid impermeable outer cover with an absorbent core positioned therebetween. The laminate can form any portion of the absorbent article including a portion of the absorbent article including the top sheet. If desired, the absorbent article can further include a liquid acquisition layer positioned between the topsheet and the absorbent core and the top sheet can be bonded to the liquid acquisition layer.
In specific embodiments the absorbent article can be, for example, a diaper, training pant or an adult incontinence product such as a pull-on pant or diaper. It can also be a feminine hygiene product such as a sanitary napkin or a panty liner.
Turning to
To separate the first layer 20 from the second layer 40, the first layer 20 is provided with a plurality of downwardly depending (in the above-referenced Z or vertical direction) embossments 23. By “downwardly depending” it is meant that material from the X-Y plane of the first layer 20 is permanently displaced in the vertical or Z-direction so as to form depressions or wells 38 which extend from the first layer bottom surface 22 towards and contacting the second layer upper surface 41. As shown in
When the laminate 10 is being used as a body side layer also referred to as a liner material or top sheet in personal care absorbent articles, rapid fluid intake and transfer of fluids down into the lower, internal layers of the absorbent product is a highly desirable attribute. Once the fluids have been transferred to the internal portions of the absorbent product, it is also desirable that the fluids so delivered not flow back up to the top surface of the laminate/top sheet of the product. This is referred to as rewet. To facilitate such properties, first layer 20 of the laminate 10 is provided with a plurality of first layer apertures 24 which extend from the first layer top surface 21 down and through the first layer bottom surface 22. See
As a result of the use of the first layer embossments 23, an air gap 35 is created between the first layer 20 and the second layer 40 and in particular, between the first layer bottom surface 22 and the second layer upper surface 41. These two surfaces (22 and 41) define an air gap thickness 36. The air gap thickness 36 can range between about 0.1 and about 15 millimeters (mm), alternatively, between about 0.1 and about 4 mm and, alternatively, between about 0.1 and about 1 mm.
The first layer 20 can be made from a wide variety of fibrous nonwoven webs such as through air bonded carded webs (TABCW), thermally bonded calendered webs, airlaid webs, spunbond webs, spunlace webs, meltblown webs, and apertured polymeric films such as polyethylene films. Through air bonded carded webs are particularly useful as the first layer 20 due to their softness and hand. With respect to the fibrous webs used for the first layer, the fibers (also referred to as filaments) can be more continuous such as are encountered with spunbond and meltblown fibrous webs. Alternatively the fibrous nonwoven webs can be made from staple fibers. Both the filaments and fibers can include, but are not limited to, single component fibers and multi-constituent fibers such bicomponent fibers. Suitable fiber compositions include, but are not limited to, polyolefins such as polypropylene and polyethylene as well as polyester, viscose, rayon and cotton. Due to their combinations of bonding capability, softness and strength, bicomponent fibers with polyethylene sheaths and polypropylene or polyester cores have been found to work particularly well with the laminate 10 described herein. Fiber deniers for the fibers can be between about 0.05 and about 5 denier, alternatively between about 1.2 and about 3 denier and, alternatively between about 1.5 and about 2.5 denier.
The second layer 40 can utilize the same materials as the first layer 20 including fibrous nonwoven webs and film layers. Because the second layer will not typically come in contact with the end-user, it may be made with higher denier fibers that the first layer 20. The fibers of the second layer 40 can be within the same ranges as denoted for the first layer 20 but can also be between about 0.05 and about 12 denier, alternatively between about 1 and about 9 denier and, alternatively between about 2 and about 6 denier.
If desired, either one or both of the first layer 20 and the second layer 40 may be treated with fluid-handling treatments such as surfactants to increase fluid flow down into the laminate 10 and the subjacent layers when the laminate 10 is included in end-use products such as the aforementioned absorbent articles.
The first layer 20 will typically have a thickness of between about 0.1 and about 5.0 millimeters (mm), alternatively between about 0.3 and about 1.5 mm and alternatively between about 0.4 and about 0.6 mm. Still further ranges and specific thicknesses may be used depending upon the particular end use of the laminate 10. The basis weight of the first layer 20 will also depend upon the particular end use but will typically have a basis weight of between about 5 and about 100 grams per square meter (gsm), alternatively between about 12 and about 50 gsm and alternatively between about 20 and about 50 gsm. Still further ranges and specific basis weights may be used depending upon the particular end use of the laminate 10.
The second layer 40 can have a basis weight of between about 10 and about 150 gsm, alternatively between about 15 and about 60 gsm, and, alternatively between about 20 and about 35 gsm. The second layer thickness 45 of the second layer 40 can be between about 0.2 and about 10 mm, alternatively between about 0.3 and about 2 mm, and alternatively between about 0.4 and about 1 mm. The overall thickness 34 of the laminate 10 can be between about 0.5 and about 20 mm, alternatively between about 1 and about 5 mm, and alternatively between about 1.5 and about 3 mm. The laminate 10 can have a total basis weight of between about 15 and 250 grams per square meter (gsm), alternatively between about 27 and about 110 gsm and, alternatively between about 40 and about 60 gsm.
The size, shape and number of first layer embossments 23 can be varied depending upon the particular end attributes of the overall laminate 10. Larger numbers of embossments will provide greater structural rigidity between the first layer 20 and the second layer 40. The number and size of the embossments can also depend on the size, shape and density of the fibers as well as the degree of fiber-to-fiber bonding between individual fibers in the first layer 20 and the second layer 40. Larger fibers with more fiber-to-fiber bonding will create more rigid embossments as will the degree of fusion during the bonding of the embossments bottoms 30 to the second layer upper surface 41. Also, depending upon the degree of fusion of the fibers that takes place in the embossments 23, the sidewalls 29 and bottoms 30 of the first layer embossments 23 may melt to a point that further stiffening and rigidity can be built into the embossments 23. Additionally, it is possible to subject the laminate 10 to post treatments such as additional heating steps to further set and fuse the fibers forming the first layer embossments 23.
The size of the embossments 23 can be varied depending upon the end use. Also, the shape of the embossments 23 can be varied and can include, but is not limited to, circles, ovals, squares, rectangles and other multi-sides openings such as diamonds, triangles, octagons, hexagons and other polygon shapes. The shapes may also be regular or irregular. Still further, combinations of embossment shapes and sizes can be used if so desired. They also may have aspect ratios (major to minor axes ratios) of between about 1:1 to about 20:1, alternatively between about 1:1 to about 5:1, and still further between about 1:1 to about 3:1.
The first layer embossments 23 can have a depth (as measured from the first layer top surface 21 to the embossment bottom 30) of between about 0.2 and about 20 mm, alternatively between about 0.4 and about 5.5 mm and, alternatively between about 0.5 and about 1.6 mm. The first layer embossments 23 can have an individual embossment area (as measured at the first layer top surface 21) of between about 1 and about 35 square millimeters (mm2), alternatively between about 1.5 and about 20 mm2 and, alternatively between about 2.5 and about 8 mm2. The overall open area of the plurality of embossments per unit area of the first layer 20 as measured at the first layer top surface 21 can be between about 5 and about 55 percent, alternatively between about 10 and about 35 percent and, alternatively between about 15 and about 25 percent.
The first layer apertures 24 can have a diameter (as measured as the greatest distance between two sides of the aperture without touching an intermediate side edge) of between about 0.2 and about 10 mm, alternatively between about 0.2 and about 5 mm and, alternatively between about 0.5 and about 2 mm. The first layer aperture spacing (as measured as the distance between the two closest respective aperture edges of two adjacent apertures at the first layer top surface 21) can be between 0.5 and about 20 mm, alternatively between about 0.5 and about 15 mm and, alternatively between about 1 and about 6 mm. The overall open area of the plurality of apertures per unit area of the first layer 20 as measured at the first layer top surface 21 can be between about 1 and about 40 percent, alternatively between about 5 and about 30 percent and, alternatively between about 10 and about 20 percent.
The size, shape and number of first layer aperture 24 can be varied depending upon the particular end attributes of the overall laminate 10. Also, the size, shape and number of first layer apertures 24 will affect the overall fluid transfer properties of the first layer 20 and the resultant laminate 10. The first layer apertures 24 can have various shapes and combinations of shapes including, the same or different shapes as described above with respect to the first layer embossments 23. Also, combinations of sizes of apertures can be used. For example, if the laminate 10 is being used as a top sheet for a personal care absorbent article such as a diaper of sanitary napkin, a middle region of the topsheet may use larger aperture sizes that the apertures located in the lateral portions of the top sheet or in the peripheral portions of the top sheet.
When the laminate 10 is being used as a body side layer of a personal care product such as a diaper, diaper pant, training pant, feminine hygiene product, adult diaper, incontinence product, etc., it is desirable that the body contacting layer be soft to the touch. This is why it is preferable that the first layer 20 be a fibrous nonwoven web. The second layer 40 will typically not come in contact with the body of the user, thus, while it is still desirable that the second layer 40 also be a fibrous nonwoven web, it may be formed from other materials such as films and film/nonwoven laminates. In such situations, it is necessary that the second layer 40 and the laminate 10 as a whole be able to pass body fluids including liquids such as urine, menses and blood and to some extent solids such as feces. As a result, in such situations, it will be advantageous for the film to have apertures, slits or some other type of fluid passageways. When the second layer 40 comprises a fibrous nonwoven web, it may use the same types, thicknesses and basis weights of fibrous nonwoven webs as delineated above with respect to the first layer 20. Thus, the first layer 20 and the second layer 40 may be the exact same material or different materials. For example, the first layer 20 may be a through-air bonded carded web and the second layer 40 may be a spunbond nonwoven web or an airlaid web.
The area of the first layer top surface 21 not taken up by the first layer embossments 23 and the first layer apertures 24 is referred to as the first layer land area 28. See
The laminate 10 shown in
Turning to
Referring again to
The overall design of the embossments 23 and apertures 24 can be varied to meet the needs of the particular laminate and/or product into which the laminate 10 will be incorporated. Turning to
Other designs as to the first and second arrays 118 and 119 are also within the scope of the present invention. Straight lines, circles, ovals and fanciful designs may be used for either or both of the arrays. In addition, one array may partially or wholly encircle the other array. Further, additional arrays, beyond a first and second arrays, may be used in the design of a laminate 10 according to the present invention.
A process 100 for making the laminate 10 is shown in
The embossing male pins 112 are shaped to form the first layer embossments 23 shown in
The second roll 120 has a plurality of embossing female recesses 123 and aperturing female recesses 124 which are in respective mating relationship with the embossing male pins 112 and aperturing male pins 114 in first roll 110 so that the respective pins mate with the respective recesses as the first roll 110 and the second roll 120 are counter-rotated in the direction of arrows 101. The size of the recesses (123 and 124) should be designed to be able to receive the respective pins (112 and 114) and the material from the first layer 20. To facilitate the aperturing and embossing, the first roll 110 and/or the second roll 120 can be heated and/or cooled using conventional means or they may be run at ambient conditions.
In the specific process shown in
In alternate designs, not shown, the second roll 120 may have a malleable surface instead of recesses that will deform when contacted by the embossing male pins 112 and aperturing male pins 114 of the first roll 110. In yet further alternate designs, some portion of the pins and recesses may be relocated from the first roll 110 to the second roll 120 and vice versa.
To increase the efficiency and speed of the present process 100, the first roll 110 defines a first roll embossing region 111, a first roll merging region 113, a first roll bonding region 115 and a first roll take-off region 117. The nip 122 is located in the embossing region 111 and a bonding apparatus 140 is located in the first roll bonding region 115.
In operation, the first layer material 20 is fed onto the second roll 120 and into the nip 122 in the first roll embossing region 111. As shown in
In the first roll merging region 113, the second layer 40 is fed onto the exposed first layer bottom surface 22. To facilitate the deposition of the second layer 40 into the first roll merging region 113, an optional guide roll 132 may be employed to maintain sufficient tension to retain the second layer upper surface 41 in contact with the first layer bottom surface 22.
As the now juxtaposed first and second layers 20 and 40 continue to travel around the first roll 110, they move into the first roll bonding region 115 where bonding of the two layers (20 and 40) takes place to form the laminate 10. As previously mentioned, the first roll 110 may be heated to facilitate the bonding step in the bonding region 115. Adjacent the first roll surface 116 of the first roll 110 in the bonding region 115 there is located a bonding apparatus 140. As shown in
As the now-formed laminate 10 leaves the first roll bonding region 115, it travels to the first roll take-off region 117 where the laminate 10 is removed for further processing or wind-up on a take-up roll (not shown). As with the other regions on the first roll 110, an optional guide roll 134 may be employed.
In an alternate embodiment, not shown, the ultrasonic bonding apparatus 140 may be replaced by a bonding roll (not shown) which supplies sufficient pressure against the second layer lower surface 42 of the second layer 40 to cause the bonding of the two layers (20 and 40) to one another. Further, if desired, the alternate bonding roll may be heated to facilitate the bonding process.
The laminate 10 shown in
An enlarged view of the first roll 110 and the second roll 120 is shown in
The laminate 10 can be used in a wide variety of applications including, but not limited to, absorbent articles and in particular, personal care absorbent articles designed to be worn against or around the body to absorb body exudates. Examples of such articles include, but are not limited to, diapers, diaper pants, training pants also known as pull-on diapers or pants, adult incontinence products and feminine care products such as sanitary napkins, panty liners, etc. Turning to
In yet other applications, the laminate 10 may be used as a wet or dry wipe as in the case of personal care wipes for babies, children and adults. Such wipes may also be employed as cleaning wipes for household and other uses. In such applications, the laminate may be loaded with cleaning and other compounds. Further, it may be treated or impregnated with other materials such as shoe polish, medications, facial creams, lotions, etc. In this regard, the air gap 35 may be used as an area to store and subsequently deliver such additional materials. The laminate 10 may also be used for medical and health care applications.
The thickness value of a selected sample is determined using a thickness tester which includes a granite base having a vertical clamp shaft extending from the top surface of the granite base which is flat and smooth. A suitable granite base is a Starret Granite Base, model 653G (available from The L.S. Starrett Company, having a place of business located in Athol, Mass., U.S.A.) or equivalent. A clamp arm is secured to the clamp shaft at one end of the clamp arm, and a digital indicator is secured to the clamp arm at the opposing end. A suitable indicator is a Mitutoyo ID-H Series 543 Digimatic Indicator (available from Mitutoyo America Corp., having a place of business located in Aurora, Ill., U.S.A.) or equivalent. Extending downward from the indicator is a vertically-movable plunger. To perform the procedure, a block having a length of 130 mm, a width of 45 mm and a thickness of 17 mm and a weight of 120 grams is placed onto the granite base. The block is constructed of acrylic and is flat and smooth on at least the bottom surface. The thickness and weight of the block is configured such that the thickness tester provides a pressure to the sample of 0.02 kPa (0.029 psi). Next, the thickness tester is gently lowered such that the bottom surface of the plunger is in direct contact with the top surface of the block at the longitudinal and transverse center of the block, and the plunger length is shortened by about 50%. The digital indicator is then tared (or zeroed) by pressing the “zero” button. The digital display of the digital indicator should display “0.00 mm” or equivalent. The thickness tester is then raised and the block is removed. The test sample is then placed onto the top surface of the granite base and the block is gently placed on top of the test sample such that the block is substantially centered longitudinally and transversely on the sample. The thickness tester is then gently lowered again onto the block such that the bottom surface of the plunger is in direct contact with the top surface of the block at the longitudinal and transverse center of the block, and the plunger length is shortened by about 50%, to provide a pressure of 0.02 kPa (0.029 psi). After 3 seconds, the measurement from the digital display is recorded to the nearest 0.01 mm.
One advantage of the present invention is the ability of the laminate 10 to create a more three-dimensional structure due to the separation between the first layer 20 and the second layer 40 and the air gap 35 therebetween. An important aspect of the laminate 10 in this regard is to maintain this three-dimensional aspect even after being subjected to compressive loads. For example, when the laminate 10 is used as a top sheet 210 in an absorbent article such as is shown in
To demonstrate the compression resilience of the laminate 10 as compared to non-apertured, non-embossed layers of materials, a series of samples were prepared and tested. The first layer material was a through air bonded carded web (TABCW) made entirely from 38 millimeter (mm), two denier polyethylene sheath/polyester core bicomponent staple fibers. The first layer had a basis weight of 24 grams per square meter (gsm). The second layer material was also a TABCW made from 38 mm, three denier polyethylene sheath/polyester core bicomponent staple fibers. The second layer had a basis weight of 30 gsm and was not apertured.
Samples designated “A” were made in a non-laminated configuration by layering together layers of the above-described first material (24 gsm) with the second material (30 gsm). In samples where multiple layers were used, the first and second materials were layered in an alternating fashion. Neither layer (24 gsm and 30 gsm) of the non-laminated samples (Samples “A”) was subjected to any embossing or aperturing nor were they laminated or otherwise joined to one another.
Samples designated “B” were subjected to a lamination process such as is shown in
Samples A and B were formed and tested as: two layers of nonwoven (non-laminated) versus a two layer laminate as disclosed herein; four layers of nonwoven (non-laminated) versus two, two layer laminates as disclosed herein; and, six layers of nonwoven (non-laminated) versus three, two layer laminates as disclosed herein. In the four and six layer versions, the layers were alternated (24 gsm/30 gsm/24 gsm/30 gsm for the four layer version and 24 gsm/30 gsm/24 gsm/30 gsm/24 gsm/30 gsm for the six layer version).
Each of the non-laminated and laminated samples measured 300 mm by 100 mm. For each sample, the thickness was measured under a load of 700 grams. Each sample was placed on a standard laboratory table at room temperature with the 24 gsm layer being the uppermost layer of the respective non-laminated (A) and laminated (B) samples. The laminated samples were stacked with the first layer top surfaces 21 of each laminate 10 facing upwardly, away from the surface of the laboratory table.
A 700 gram weight measuring 120 mm long by 80 mm wide by 26 thick was used to compress each of the above-described samples. The side measuring 120 mm by 80 mm was centered on and contacted each of the samples and left on the samples for a period of three hours. At the end of the three hour period, the 700 gram weight was removed and the samples were left on the table undisturbed for an additional 30 minutes before a final thickness measurement was taken. All thicknesses (original, end of three hours and at three and one-half hours) were measured using the thickness test described above using a 120 gram load. The results of these measurements are set forth in Table 1 below. “Thickness 1” was the thickness of the layers or laminate(s) as the case may be before the 700 gram load was applied. “Thickness 2” was the thickness of the layers or laminate(s) after the above load had been removed at the end of the three hour period. “Thickness 3” was the thickness after the 30 minute resting period had ended. All three thickness measurements were done according to the above thickness testing procedure under a load of 120 grams. Each value reported in Table 1 is for an average of three samples. The “Tolerance” for each Thickness (Thickness 1, Thickness 2 and Thickness 3) is the thickness value for Sample A minus the thickness of Sample B. The “percent recovery” for each of the Samples A and B was the value of Thickness 3 divided by the Thickness 1 with the quotient multiplied by 100. The “Difference” was the percent recovery of Sample B divided by the percent recovery of Sample A with the quotient multiplied by 100.
As can be seen from Table 1 above, in all cases the non-laminated samples (Samples A) had a higher percentage recovery of their thickness after the load was removed [(Thickness 3÷Thickness 1)×100] versus the laminate materials of the present invention. However, the laminates while not recovering to the level of the non-laminates, did have differences in recovery [(Sample B recovery÷Sample A recovery)×100] that were very close to the non-laminates (98.5%; 90.1%; and 95.8%). What this demonstrates is that the laminates 10 with the air gaps 35, were able to maintain a high level of their separation between the first layer 20 and the second layer 40 due to the first layer embossments 23. As a result, even in use, such as when the laminate 10 is used as a topsheet 210 in the absorbent articles 200 and 202 shown in
It will be recognized that the present invention is capable of many modifications and variations without departing from the scope thereof. Accordingly, the detailed description and examples set forth above are meant to be illustrative only and are not intended to limit, in any manor, the scope of the invention as set forth in the appended claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN15/77988 | 4/30/2015 | WO | 00 |
