Nonwovens and absorbent articles having nonwovens

Abstract

The present invention relates to a three-dimensional nonwoven comprising a first side, a second side, a protruding first region comprising an upper part formed in the first side and a lower part formed in the second side, and a second region comprising a plurality of deformations, wherein the shape memory index of the upper part is higher than the shape memory index of the lower part; to an absorbent article comprising the three-dimensional nonwoven and to a method for producing the three-dimensional nonwoven.

Description

Technical Field

[0001] The present invention relates to nonwoven fabrics, methods of manufacturing the nonwoven fabrics, and absorbent articles comprising the nonwoven fabrics. Background Technology

[0002] Nonwoven fabrics, including those made of synthetic fibers from thermoplastic resins, are widely used as sheets to form absorbent products such as sanitary napkins, disposable baby diapers, and personal care disposable diapers.

[0003] These absorbent articles comprise several layers that provide different functions. A liquid-permeable topsheet is positioned closest to the wearer's skin and should be able to quickly absorb excreted fluids. A backsheet is positioned on the opposite side of the article facing the clothing. Some absorbent articles on the market also include an outermost nonwoven layer forming at least a portion of the clothing-facing surface of the absorbent article. Other components of absorbent articles are well known and specifically include an absorbent core disposed between the topsheet and the backsheet to absorb and retain excreted fluids.

[0004] Three-dimensional nonwovens incorporating three-dimensional elements can provide process awareness. Three-dimensional substrates can also offer improved fluid handling properties and enhanced sensory experiences, such as skin softness and cushioning.

[0005] In some configurations, the nonwoven fabric is supplied on rollers and moved to the absorbent article manufacturing location. During absorbent article assembly, the nonwoven fabric is unwound from the rollers and supplied to an assembly line that transforms the nonwoven material into the absorbent article. In some cases, the nonwoven fabric may be wound relatively tightly on the rollers, and the associated high winding pressure can compress the nonwoven web, resulting in a reduction in thickness. When incorporated into absorbent articles, such compressed nonwoven webs can have a thin appearance, which conveys a message of less softness to consumers and / or may be less aesthetically pleasing. They can also adversely affect various properties of the nonwoven web. To mitigate the problems associated with nonwoven compression, some manufacturers apply heat to the nonwoven fabric as it is unwound from the rollers. Subsequently, applying heat to some types of nonwoven fabrics can increase the thickness or volume of the web material, a process referred to herein as “re-fluffing.”

[0006] JP5203349B discloses a nonwoven fabric comprising thermoplastic fibers, multiple raised portions, and recessed portions, wherein the thermoplastic fibers constituting the upper portion of the raised portion have a lower thermal elongation rate compared to the thermoplastic fibers constituting the lower portion, and are low-temperature thermoplastic raw material fibers that begin to thermally elongate at a relatively low temperature. Thermoplastic fibers rely on unique fiber properties obtained through a unique fiber production process, which may limit their application in various industries due to the complexity of the process and high production costs.

[0007] Meanwhile, in absorbent articles with nonwoven top sheets, nonwovens with capillary gradients have always been desirable because they can provide better fluid drainage from the surface of the top sheet to adjacent layers, which can improve the dryness and / or cleanliness of the absorbent article.

[0008] There is a persistent need for a cost-effective nonwoven fabric capable of producing a well-perceived three-dimensional appearance, and an absorbent article having such a nonwoven fabric.

[0009] There is a persistent need for a cost-effective nonwoven fabric that can produce a well-perceptible three-dimensional appearance and provide improved fluid handling performance, as well as an absorbent article having such a nonwoven fabric.

[0010] There is a persistent need for a cost-effective method to produce three-dimensional nonwovens. Summary of the Invention

[0011] The present invention provides an absorbent article comprising a skin-facing surface, a clothing-facing surface, a liquid-permeable top sheet, a liquid-impermeable bottom sheet, an absorbent structure disposed between the top sheet and the bottom sheet, and a three-dimensional nonwoven fabric, wherein the three-dimensional nonwoven fabric includes a first side surface, a second side surface, a protruding first region, and a second region, the protruding first region including an upper portion formed in the first side surface and a lower portion formed in the second side surface, the second region including multiple deformations, and wherein the shape memory index of the upper portion is higher than that of the lower portion.

[0012] The present invention also provides a three-dimensional nonwoven fabric including a first side, a second side, a protruding first region, and a second region. The protruding first region includes an upper portion formed in the first side and a lower portion formed in the second side. The second region includes multiple deformations, wherein the shape memory index of the upper portion is higher than that of the lower portion.

[0013] The present invention also provides a method for producing a three-dimensional nonwoven fabric, the method comprising the steps of: (a) forming a first fiber web and forming a second fiber web; (b) forming a composite fiber web by covering the second fiber web with the first fiber web, wherein the first fiber web forms a first side surface of the composite fiber web and the second fiber web forms a second side surface of the composite fiber web; (c) bonding the composite fiber web to bond at least a portion of the fibers constituting the first fiber web and the second fiber web, thereby obtaining a precursor nonwoven fabric; and (d) processing the precursor nonwoven fabric via a deformation forming unit to form deformation in predetermined regions to obtain a deformed nonwoven fabric including at least one protruding first region and a plurality of deformed second regions, wherein the protruding first region includes an upper portion in the first side surface and a lower portion in the second side surface, and wherein the shape memory index of the upper portion is higher than that of the lower portion.

[0014] These and other features, aspects and advantages of the present invention will become apparent. Attached Figure Description

[0015] Figure 1 It is a plan view of a nonwoven fabric.

[0016] Figure 2 yes Figure 1 A schematic cross-sectional view of a nonwoven fabric.

[0017] Figure 3 It is a two-dimensional photograph of a nonwoven fabric.

[0018] Figure 4 It is a two-dimensional image of a nonwoven fabric.

[0019] Figure 5 It is a two-dimensional photograph of a nonwoven fabric.

[0020] Figures 6A-6C This is a schematic diagram of the shape memory effect.

[0021] Figure 7 This is a schematic diagram of an exemplary method for forming the three-dimensional nonwoven fabric of this disclosure.

[0022] Figure 8 It is a partial interlocking engagement of a pair of rollers according to this disclosure to form Figure 1 A view of the pattern shown.

[0023] Figure 9 yes Figure 8 A view of a portion of the first roller in a pair of rollers.

[0024] Figure 10 yes Figure 8A view of a portion of the second roller in a pair of rollers.

[0025] Figure 11 This is a view of another part of the first roller.

[0026] Figure 12 Is with Figure 11 The first rollers in the middle mesh with each other to form Figure 3 A view of a portion of the second roller of the pattern shown.

[0027] Figure 13 This is a microscopic image of a cross-section of nonwoven fabric 4.

[0028] Figure 14 This is another microscopic image of a cross-section of nonwoven fabric 4.

[0029] Figure 15 This is a microscopic image of the cross-section of nonwoven fabric 7.

[0030] Figure 16 This is another microscopic image of a cross-section of nonwoven fabric 7. Detailed Implementation

[0031] All ranges are inclusive and combinable. The number of significant digits does not limit the quantity indicated or the precision of the measurement. All numerical values ​​should be understood to be modified by the word "about" unless otherwise specified.

[0032] As used in this article, "absorbent products" include disposable diapers, sanitary napkins, panty liners, incontinence pads, labial pads, breastfeeding pads, sweat sheets, animal excrement treatment products, and animal diapers.

[0033] As used herein, the term “component” in absorbent article refers to the various parts of absorbent article, such as the top sheet, second layer, collection layer, liquid treatment layer, absorbent core, or the layers and bottom sheet of the absorbent core.

[0034] Three-dimensional nonwovens

[0035] As used herein, the term "nonwoven fabric" refers to a fiber web having an interwoven structure of single fibers or yarns but not exhibiting a repeating pattern as in woven or knitted fabrics, which typically do not have randomly oriented fibers. Nonwoven fabrics or textiles have been formed by a variety of methods, such as, for example, meltblown, spunbond, hydroentangling, air-laid, wet-laid, air-dried papermaking, and bonded carding, including carded thermal bonding. Nonwoven fabrics may include unbonded fibers, wound fibers, towed fibers, etc. Fibers may be stretchable and / or elastic and pre-stretched for processing. Fibers may be continuous, such as those produced by spunbond methods, or cut to a certain length, such as those commonly used in carding methods. Fibers may be bicomponent, multicomponent, molded, crimped, or in any other formulation or configuration known in the art regarding nonwoven fabrics and fibers. Generally, fibers can be bonded by chemical bonding (e.g., by latex or adhesive), pressure bonding, or thermal bonding. If thermal bonding is used in the bonding process described below, a certain percentage of thermoplastic materials, such as thermoplastic powders or fibers, can be used.

[0036] This invention provides a three-dimensional nonwoven fabric suitable for components of absorbent articles. Figure 1 A plan view of the nonwoven fabric according to the present invention is shown. Figure 2 schematically shown Figure 1 A cross-sectional view of a nonwoven fabric. Figure 3 This is a plan view photograph of another exemplary nonwoven fabric according to the present invention. See also Figure 1 and Figure 2 The nonwoven fabric 30 has a first side 32, a second side 34, and includes at least one protruding first region 2 and a second region 4, the second region including multiple deformations, in these cases, holes. In one embodiment, the three-dimensional nonwoven fabric 30 includes a plurality of protruding first regions 2. When the three-dimensional nonwoven fabric 30 includes a plurality of protruding first regions 2, each of the protruding first regions may be substantially surrounded by a second region. "Substantially surrounded" herein means that at least 80% of the perimeter of the first region is surrounded by the second region. In another embodiment, the three-dimensional nonwoven fabric 30 includes a plurality of second regions 4.

[0037] First District

[0038] See Figure 1 and Figure 2The three-dimensional nonwoven fabric 30 includes a first side surface 32, a second side surface 34 opposite to the first side surface 32, and a protruding first region 2. This protruding first region includes an upper portion 22 formed in the first side surface 32 and a lower portion 24 formed in the second side surface 34. The protruding first region 2 provides a three-dimensional profile for the nonwoven fabric 30. The upper portion 22 formed in the first side surface 32 has a higher shape memory index than the lower portion 24. Utilizing the higher shape memory index, the upper portion can generate a well-recognizable three-dimensional perception when heat-treated on the first side surface. Because the upper portion 22 has a higher shape memory index than the lower portion 24, when the nonwoven fabric is heat-treated, the upper portion 24 has a lower density structure and lower capillary pressure than the lower portion 22, thereby generating a capillary gradient in the nonwoven fabric 30. The nonwoven fabric 30 with a capillary gradient provides better fluid discharge from the first side 32 to the second side 34 of the nonwoven fabric 30, and improves the dryness and / or stain masking of the absorbent article when the nonwoven fabric is used as a component of the absorbent article, such as a top sheet.

[0039] The upper part 22 may have a shape memory index of not less than about 120%, or not less than about 125%, or not less than about 130%. The lower part has a shape memory index of less than about 120% or less than about 115%.

[0040] The shape memory effect is the ability of a material to recover its shape when an external stimulus is applied. The shape memory effect and shape memory fibers have been reported in publications such as "Shape-Memory Polymers," Angew. Chem. Int. Ed. 2002, 41, 2034-2057, and "Recent advances in shape memory polymers and composites: a review," J Mater Sci (2008) 43: 254-269. Shape recovery induced by temperature changes is called the thermally induced shape memory effect. See also... Figures 6A-6C The material 100, including fiber 102, acquires its permanent shape during conventional processing (such as heat treatment and / or machining). Figure 6A The fiber contains a shape memory polymer. Subsequently, when material 100 is deformed, for example, when material 100 is compressed, the desired temporary shape is fixed. Figure 6B A permanent shape is now stored in material 100, while material 100 exhibits a temporary shape. Heating material 100 above the transition temperature of the shape memory fibers 102 constituting material 100 induces a shape memory effect and results in the recovery of the stored permanent shape. Figure 6C ).

[0041] The protruding first region 2 has an upper height 22h and a lower height 24h, the lower height being less than the upper height 22h. The upper height 22h may be no less than approximately 0.80 mm to provide well-identifiable three-dimensional perception.

[0042] The lower part height should not exceed the upper part height over 24 hours. The lower part height should not exceed approximately 0.2 mm.

[0043] Due to its small lower height 24h, the second side 34 is essentially flat, which allows for good connectivity between the second region 4 and adjacent layers when the nonwoven fabric 30 is used as a component of an absorbent article. For example, when the nonwoven fabric 30 is used as the top sheet of an absorbent article, the good connectivity between the nonwoven fabric 30 and adjacent absorbent layers enables the absorbent article to perform rapid liquid collection and leave less fluid on the top sheet. Typically, absorbent articles with three-dimensional top sheets rely on high-density embossing to bond the top sheet nonwoven fabric to adjacent absorbent layers to enhance connectivity between the top sheet and adjacent absorbent layers, but this can adversely affect the softness and cushioning of the top sheet as well as the collection speed.

[0044] Without being bound by theory, the nonwoven fabric 30 has a distinct and satisfactory three-dimensional appearance in the first side 32 with the prominent first region 2 because the upper part 22 has a high shape memory index, enabling it to recover its permanent shape at a high rate. Since the lower part 24 does not recover or only slightly recovers its permanent shape due to its low shape memory index, the nonwoven fabric can have a substantially flat second side 34. By means of a second region 4 having multiple deformable features that cause the second region 4 to be recessed, the first region 2 with the upper part 22 can produce a three-dimensional first side in the nonwoven fabric, wherein the upper part has a high shape memory index.

[0045] The upper portion 22 may include thermoplastic fibers. The upper portion may include thermoplastic conjugated fibers comprising a first polymer component and a second polymer component, the second polymer component having a melting point lower than that of the first polymer component, wherein the first polymer component is present in a longitudinally continuous configuration on at least a portion of the surface of the conjugated fiber. The upper portion may include fibers comprising polymers selected from the group consisting of polyethylene terephthalate, polypropylene terephthalate, polybutene, polyethylene terephthalate copolymers, poly(tetramethylene ether) glycol, and combinations thereof. Depending on the application of the nonwoven fabric, one or more types may be selected.

[0046] The lower portion may include thermoplastic fibers. The lower portion may include thermoplastic conjugated fibers comprising a first polymer component and a second polymer component, the second polymer component having a melting point lower than that of the first polymer component, wherein the first polymer component exists in a longitudinally continuous configuration on at least a portion of the surface of the conjugated fiber. The lower portion of the nonwoven fabric according to the invention may include natural fibers such as cotton, silk, wool, hemp, pulp, etc.; and regenerated fibers such as rayon, cupro, etc., resulting in a low shape memory index. Depending on the application of the nonwoven fabric, one or more types may be selected.

[0047] The thermoplastic conjugated fibers suitable for use in this invention may have two-dimensional and / or three-dimensional crimps. Hereinafter, the term "two-dimensional crimp" can be understood as mechanical crimp, wherein the peaks of the crimped fiber form acute angles. Three-dimensional crimp may refer to crimps with peaks that are curved (waveform crimp) or spiral (spiral crimp), crimps containing both waveform and spiral crimps, or crimps containing at least one of mechanical crimp and waveform and spiral crimps. In one embodiment, core / sheath composite fibers having two-dimensional crimps may offer greater cost-effectiveness compared to composite fibers having three-dimensional crimps.

[0048] The thermoplastic conjugated fibers suitable for use in this invention can be concentric or eccentric. In one embodiment, the core / skin composite fiber is a concentric fiber.

[0049] The thermoplastic fibers suitable for use in this invention can be thermoplastic homopolymer fibers.

[0050] The protruding first region is filled with fibers, and there is essentially no hollow space beneath it. Because the protruding first region is filled with fibers, the three-dimensional nonwoven fabric of the present invention can stably maintain its three-dimensional structure upon compression, and when the nonwoven fabric 30 is used as a component of an absorbent article, it can enhance the transfer of fluid to adjacent layers.

[0051] The upper portion 22 and the lower portion 24 may be continuous in the horizontal direction. The upper portion 22 and the lower portion 24 forming the protruding first region 2 are bonded by techniques known in the art. For example, the upper portion 22 and the lower portion 24 may be laminated by adhesives or thermal bonding methods, wherein thermal bonding includes, but is not limited to, techniques such as heat-ventilated bonding and ultrasonic bonding. When one of the upper and lower portions comprises a relatively high amount of natural fibers, it may be difficult to bond the first and second layers to each other by heating, because natural fibers do not become sticky or melt when exposed to heat. Therefore, the upper portion 22 is attached to the lower portion 24 in the bonding area by a hot-melt adhesive.

[0052] When used as a component of an absorbent article, the first region may be coordinated with graphics, markings, printing, inks, colors, and / or patterned adhesives, for example, located in the nonwoven fabric of the absorbent article or in another component.

[0053] Second Zone

[0054] See Figure 1 and Figure 2 The three-dimensional nonwoven fabric 30 also includes a second region 4. The second region 4 includes multiple deformations, which may include holes, recesses, or combinations thereof. In one embodiment, the second region 4 includes, for example... Figure 1 and Figure 2 The multiple holes shown.

[0055] The deformation can be any of the following: circular, elliptical, hourglass-shaped, star-shaped, polygonal, or a combination thereof. Polygonal shapes include, but are not limited to, triangles, quadrilaterals, hexagons, octagons, or trapezoids. In one embodiment, the deformation is circular. In another embodiment, the deformation is elliptical. The size of the deformation can be approximately 0.1 mm. 2 Approximately 3mm 2 Within the range, or approximately 0.2 mm 2 Approximately 2mm 2 Within the range, or approximately 0.3 mm 2 Approximately 1mm 2 Within the range. The second region may have deformations of the same size and / or shape. The second region may have deformations of different sizes and / or shapes.

[0056] The second region may include deformations that form a pattern. The pattern formed by the deformation can be any shape, such as one or more straight lines or curves, circles, ellipses, triangles, polygons, flowers, clouds, etc. The pattern can be regular, uniform, and consistent, or irregular, non-uniform, and inconsistent. In some embodiments, the nonwoven fabric of the present invention includes multiple second regions, wherein the deformed patterns in the second regions do not necessarily have the same shape or size. That is, in the nonwoven fabric of the present invention, the deformed pattern in one second region may be different from the deformed pattern in another second region. The pattern can be of various shapes and / or various sizes. The nonwoven fabric of the present invention can have a consistent deformed pattern.

[0057] In some embodiments, the second region includes clustered deformations. The term "clustered deformation" as used herein means a deformation pattern in which at least one deformation has at least three adjacent deformations, wherein the single deformation and each of the at least three adjacent deformations have an edge-to-edge spacing S (the shortest distance between the edge of one deformation and the edge of an adjacent deformation) not greater than about 3 mm. See also Figure 1 The second region 4 includes a hole 6a having at least three adjacent holes 6b, 6c and 6d, wherein the edge-to-edge spacing S between each hole 6a and each of holes 6b and 6c is approximately 0.60 mm.

[0058] Figure 3 and Figure 4 This is another example having at least one second region, which has clustered deformation.

[0059] Without being bound by theory, it is believed that the clustered deformation in the second region acts similarly to anchor points in a nonwoven fabric, preventing the nonwoven fabric from regaining its bulkiness. This contributes to the formation of a clear three-dimensional structure due to the significant thickness difference between the first and second regions. Furthermore, the clustered deformation in the second region acts similarly to anchor points in a nonwoven fabric, and requires more work input to compress the nonwoven fabric compared to an undeformed one.

[0060] When used as a component of an absorbent article, the deformed pattern in the second region may be coordinated with, for example, graphics, markings, printing, inks, colors, and / or patterned adhesives located in the nonwoven fabric of the absorbent article or in another component.

[0061] Nonwoven configuration

[0062] The basis weight of the three-dimensional nonwoven fabric of the present invention can be appropriately selected according to the application of the nonwoven fabric. For the nonwoven fabric of the present invention as a top sheet of an absorbent article, the overall basis weight of the upper and lower parts of the nonwoven fabric can be about 25 g / m². 2 Approximately 100g / m 2 or approximately 35g / m 2 Approximately 70g / m 2 For nonwoven fabrics used as top sheets in absorbent articles, in one embodiment, the overall basis weight of the nonwoven fabric is about 30 g / m³. 2 Approximately 70g / m 2 or approximately 35g / m 2 Approximately 55g / m 2 Within the range.

[0063] The basis weight of the upper and lower parts can each be approximately 5 g / m³. 2 Approximately 50g / m 2 or about 10g / m 2 Approximately 40g / m 2 or approximately 14g / m 2 Approximately 35g / m 2 The weight ratio of the upper / lower portion can be approximately 80 / 20 to approximately 20 / 80, or approximately 60 / 40 to approximately 50 / 50. If the weight of the upper portion is too small and / or the weight ratio of the upper portion to the lower portion is too small, the nonwoven fabric may not have a clearly visible three-dimensional structure in the first side.

[0064] In one embodiment, the nonwoven fabric includes a first layer forming an upper portion and a second layer forming a lower portion. In another embodiment, the nonwoven fabric may include an intermediate layer between the first and second layers. A third layer may form either the upper or lower portion. The third layer may partially form both the upper and lower portion.

[0065] The nonwoven fabric may be hydrophilic. In one embodiment, the upper part of the nonwoven fabric of the present invention is less hydrophilic than the lower part. In another embodiment, the upper part of the nonwoven sheet of the present invention is more hydrophilic than the lower part. In yet another embodiment, the nonwoven fabric is hydrophobic.

[0066] The three-dimensional nonwoven fabric of the present invention can be a re-fluffed nonwoven fabric.

[0067] The lower part may include fibers with a fiber fineness no greater than that of the fibers in the upper part. When the nonwoven fabric is used as a component of an absorbent article, this can help introduce capillary cascades into the nonwoven fabric and more effectively transport fluid from the upper part to the lower part, thereby improving the dryness and cleanliness of the absorbent article.

[0068] Nonwoven fabric manufacturing methods

[0069] The three-dimensional nonwovens disclosed herein can be prepared by any suitable method known in the art.

[0070] The nonwoven fabric can be manufactured by a method comprising the following steps: (a) forming a first fiber web and forming a second fiber web; (b) forming a composite fiber web by covering the second fiber web with the first fiber web, wherein the first fiber web forms a first side of the composite fiber web and the second fiber web forms a second side of the composite fiber web; (c) bonding the composite fiber web to bond at least a portion of the fibers constituting the first fiber web and the second fiber web, thereby obtaining a precursor nonwoven fabric; and (d) treating the precursor nonwoven fabric via a deformation forming unit to form deformation in predetermined areas to obtain a deformed nonwoven fabric including at least one protruding first region and a plurality of deformed second regions, wherein the protruding first region includes an upper portion in the first side and a lower portion in the second side, and wherein the shape memory index of the upper portion is higher than that of the lower portion.

[0071] The first and second fiber webs can be carded fiber webs (such as parallel fiber webs, semi-random fiber webs, random fiber webs, cross-fiber webs, cross-woven fiber webs, etc.), air-laid fiber webs, wet-laid fiber webs, and spunbond fiber webs, etc.

[0072] In some embodiments, a composite fiber web is formed by using a parallel carding machine to lay a first fiber web onto a conveyor belt and covering it with a second fiber web. In other embodiments, a composite fiber web is formed by using a parallel carding machine to lay a second fiber web onto a conveyor belt and covering it with a first fiber web. The first fiber web may form a first side of the three-dimensional nonwoven fabric, and the second fiber web may form a second side of the three-dimensional nonwoven fabric. The first fiber web laid facing the conveyor belt ensures that when the three-dimensional nonwoven fabric is used as a top sheet in an absorbent article, the three-dimensional nonwoven fabric has a smooth first side with minimal pilling, such that the first side of the three-dimensional nonwoven fabric forms at least a portion of the skin-facing surface of the absorbent article.

[0073] The bonding of synthetic fiber webs can be performed using any conventional, known fiber bonding method. Examples of such bonding methods include heat-ventilated thermal bonding and ultrasonic bonding.

[0074] The deformation of a precursor nonwoven fabric to form a three-dimensional nonwoven fabric can be performed using any conventional, known nonwoven fabric deformation method. An exemplary deformation apparatus is a pair of rollers including a first roller and a second roller. See also Figure 7 The precursor nonwoven fabric 20 can be deformed by passing it through a roll gap 502 formed by a pair of rollers 500 (having two intermeshing rollers 504 and 506) to form a three-dimensional nonwoven fabric 30. At least one of the rollers 504 and 506 can be heated. Figure 8 A view showing the interlocking engagement of portions of an exemplary first and second roller in a pair of rollers.

[0075] Figure 9 This is a view of a portion of the first roller 504. Figure 10 This is a view of a portion of the second roller 506. See also: [link to implementation details] Figures 1-2 and Figures 8-10The first roller 504 can create a protruding first region 2 and a second region 4 (in conjunction with the second roller) having a plurality of holes 6 in the nonwoven fabric 30. The first roller 504 may include a plurality of tapered protrusions 508 extending radially outward from the first roller 504. The first roller 504 may also include a plurality of recesses 510 formed in the radially outer surface of the first roller 504. The second roller 506 may include a plurality of recesses 514 formed in the radially outer surface of the second roller 506. The recesses 510 formed in the first roller 504 have different dimensions, shapes, heights, areas, widths, and / or dimensions than the recesses 514 formed in the second roller 506. The recesses 510 in the first roller 504 may be configured to at least partially correspond to the outer surface of the second roller 506, thereby creating the first region 2 in the nonwoven fabric 30. The recesses 510 may be deep enough that the portion of the nonwoven fabric forming the first region 2 will be less compressed than the portion of the nonwoven fabric forming the second region 4. These recesses 510 may have a depth of not less than about 1 mm. These recesses 510 may have a depth of not less than about 50 mm. 2 or not less than approximately 70mm 2 or not less than approximately 100mm 2 The area of ​​510. If the area of ​​510 is too small, it may increase the direct heating of the first side of the nonwoven fabric, which could cause the nonwoven fabric to overheat, making the first side of the nonwoven fabric flat and possibly failing to produce the desired recognizable three-dimensional perception in the first side of the nonwoven fabric. Specifically, when the recess 510 in the first roller 504 engages with the outer surface of the second roller 506, there is sufficient space along the rotational axis between the first side of the nonwoven fabric and the surface of the recess 510, such that the upper height 22h of the nonwoven fabric 30 is higher than the lower height 24h of the nonwoven fabric 30. Compared to the case where the portion of the first roller 504 corresponding to the recess 510 is flat, this feature allows the first region 2 to have a larger upper height 22h and better softness and cushioning. Due to the recess 510, as the forebody nonwoven fabric 20 passes through the roll gap 502, the first roller 504 and the second roller 506 can create a height difference between the first region 2 and the second region 4, which determines the permanent shape of the nonwoven fabric 30. Because the first region 2 has a permanent shape with a greater height than if the portion of the first roller 504 corresponding to the recess 510 were flat, and because the upper portion 22 of the nonwoven fabric 30 has a high shape memory effect, even if compressed during packaging, storage, or conversion, the upper portion 22 can recover its three-dimensional shape at a high rate under thermal conditions.

[0076] In some embodiments, the first roller 504 has a flat area corresponding to the recess 510.

[0077] The recess 514 in the second roller 506 may be configured to at least partially receive the protrusion 508 in the first roller 504, thereby creating a hole 6 in the forebody nonwoven fabric 20 as the forebody nonwoven fabric 20 passes through the roll gap 502 formed by the first roller 504 and the second roller 506.

[0078] Figure 11 and Figure 12 This is a view (in conjunction with the second roller) of a portion of a first and second roller used for producing a three-dimensional nonwoven fabric with a prominent first region 2 and a second region 4, the second region having a plurality of holes 6, see [link to other image]. Figure 11 The first roller 504 may include a plurality of tapered protrusions 508 extending radially outward from the first roller 504. The second roller 506 may include a plurality of recesses 514 formed in the radially outer surface of the second roller 506. The recesses 514 in the second roller 506 may be configured to at least partially receive the protrusions 508 of the first roller 504, thereby creating holes 6 and forming a second region 4 in the nonwoven fabric 30. The flat region surrounded by the protrusions 508 in the first roller 504 and the flat region surrounded by the plurality of recesses 514 in the second roller 506 form a first region 2 in the three-dimensional nonwoven fabric 30.

[0079] See Figures 8-10 as well as Figure 11 and Figure 12 When the current nonwoven fabric 20 passes through the roll gap 502 formed by the first roller 504 and the second roller 506, the intermeshing engagement of the first roller 504 and the second roller 506 produces at least one first region 2 and at least one second region 4, the second region including a plurality of holes 6.

[0080] In order to make the second side 34 substantially flat, the second roller 506 is preferably heated to near and above the melting temperature of the polymer component of the fibers in the lower part 24 of the nonwoven fabric 30 (the lowest melting temperature when the fibers are composed of multiple polymers), and the speed of the roller is adjusted so that the fibers in the lower part of the precursor nonwoven fabric have sufficient time to be thermally melted, thereby making the surface of the nonwoven fabric flat.

[0081] Three-dimensional nonwovens can be further subjected to a re-bulk process to increase their bulk and enhance their three-dimensional appearance. The re-bulk process is the process of restoring the bulk of the nonwoven by providing energy to it. The re-bulk process can be carried out via various methods known to those skilled in the art. Heat sources include ovens, burners, or infrared radiation, which generate heat to raise the temperature of the nonwoven. As the temperature rises, the fibers within the nonwoven begin to soften, and at least some fibers begin to realign with and / or separate from the fibers. This realignment and / or separation of fibers results in an increase in the thickness of the nonwoven, thereby reducing its density. The final re-bulk thickness depends on the temperature and residence time, which is the total time the nonwoven is exposed to the elevated temperature during the re-bulk process.

[0082] In one implementation, the nonwoven fabric can be re-fluffed according to the method disclosed in PCT / US2019 / 066455, filed September 5, 2019. Unless expressly excluded or otherwise limited, that PCT application is incorporated herein by reference.

[0083] In another embodiment, the nonwoven fabric can be re-fluffed by heating it in an oven with applied hot air.

[0084] Absorbent products

[0085] The absorbent article according to the present invention comprises a skin-facing surface, a clothing-facing surface, a liquid-permeable top sheet, a liquid-impermeable bottom sheet, an absorbent structure disposed between the top sheet and the bottom sheet, and the three-dimensional nonwoven fabric of the present invention. Absorbent articles comprising the three-dimensional nonwoven fabric of the present disclosure can be prepared by any suitable method known in the art. Specifically, the articles can be made by hand or industrially at high speed.

[0086] The absorbent articles of the present invention can be industrially produced by any suitable method. Therefore, different layers can be assembled using standard methods such as embossing, thermal bonding, adhesive bonding, or any combination thereof.

[0087] Top film

[0088] The top sheet can trap bodily fluids and / or allow fluids to permeate into the absorbent article. When the top sheet comprises the three-dimensional nonwoven fabric of the present invention, the upper portion of the first region of the nonwoven fabric is preferably positioned on the side in contact with the skin.

[0089] negative

[0090] Any conventional liquid-impermeable film material typically used for absorbent articles can be used as the film. In some embodiments, malodorous gases emitted by the absorbed bodily excrement are impermeable to the film, preventing odor escape. The film may or may not be breathable.

[0091] Absorption core

[0092] Absorbent articles may also be intended to include an absorbent core disposed between the top sheet and the bottom sheet. As used herein, the term "absorbent core" refers to a material or combination of materials suitable for absorbing, dispensing, and storing fluids such as urine, blood, menstrual blood, and other bodily excretions. Any conventional material used for an absorbent core suitable for an absorbent article may be used as an absorbent core.

[0093] The nonwoven fabric of the present invention provides a pleasant three-dimensional perception and is suitable for components of absorbent articles.

[0094] The absorbent article of the present invention may include a top sheet comprising the three-dimensional nonwoven fabric of the present invention, such that a first side of the three-dimensional nonwoven fabric forms at least a portion of the skin-facing surface of the absorbent article.

[0095] The absorbent article of the present invention may further include an outermost layer comprising the three-dimensional nonwoven fabric of the present invention, such that a first side of the three-dimensional nonwoven fabric forms at least a portion of the surface of the absorbent article facing the garment.

[0096] Test methods

[0097] 1. Height Test

[0098] (1) Sample preparation

[0099] If the nonwoven fabric is present in its raw material form, cut a sample from the raw material to a size of approximately 25 mm × 25 mm or larger, to include at least one complete protruding first region and portions of two adjacent second regions. If the nonwoven fabric is a component layer of an absorbent article, such as a top sheet, cut the absorbent article to that size and remove the nonwoven layer from the absorbent article by cutting it from the layer beneath the absorbent article using a razor blade. If necessary, a low-temperature spray (such as Cyto-Freeze, Control Company, Houston TX) or other suitable solvent that does not permanently alter the properties of the nonwoven layer composition can be used to remove the nonwoven layer sample from the underlying layer. Tetrahydrofuran (THF) can be used as a solvent to remove any residual adhesive from the sample using the following steps.

[0100] 1) In a fume hood, transfer 1 liter of THF to a 3-4 liter beaker.

[0101] 2) Immerse the sample in 1 liter of THF.

[0102] 3) Place the beaker on a shaker and stir gently for 15 minutes, then let the solution containing the sample stand for another 5 minutes.

[0103] 4) Remove the sample from the THF solution and carefully squeeze the THF solution out of the sample.

[0104] 5) Allow the sample to air dry in a fume hood for at least 15 minutes.

[0105] To obtain a nonwoven fabric cross-sectional sample, the nonwoven fabric is placed on a flat worktable with the first side facing upwards and cut along line 2-2 to cut at the apex height of the protruding first region 2. The cut protruding first region 2 is then sandwiched between the second regions 4. See [reference needed]. Figure 1 and Figure 2 .

[0106] (2) Image generation

[0107] Microscopic images of the nonwoven samples were taken using an optical microscope, a 3CCD optical microscope (Keyence VHX5000), or an equivalent instrument, and were used to measure the upper and lower heights of the nonwovens.

[0108] Use double-sided conductive tape to place the nonwoven sample on the microscope stage or tap it to secure the sample. Select an appropriate magnification to ensure the features in the nonwoven sample are sufficiently clear and magnified for measurement.

[0109] (3) Height measurement

[0110] See Figure 2 First, draw line L12, which connects the first side surface of a second region 4 to the adjacent second region 4 that sandwiches the first region 4. Then, draw another line L11 parallel to line L12, which contacts the vertex of the upper part 22 of the first region 2. The distance between lines L11 and L12 is measured and reported as the upper height 22h. Next, draw line L22, which connects the second side surface of the second region 4 to the adjacent second region 4 that sandwiches the first region 4. Then, draw another line L21 parallel to line L22, which contacts the vertex of the lower part of the first region 2. The distance between lines L21 and L22 is measured and reported as the lower height 24h.

[0111] The report is accurate to 0.01 mm in height. For each nonwoven sample, three images of different cross-sectional portions of the nonwoven fabric are tested. The reported value is the average of the three recorded measurements for each nonwoven fabric.

[0112] 2. Shape Memory Index Test

[0113] (1) Freshness

[0114] Fresh Height: After conditioning the nonwoven fabric under 12 kPa pressure for 3 hours, the height of the upper and lower parts of the nonwoven fabric under fresh conditions was measured according to the height test.

[0115] (2) Restore height

[0116] Height recovery: After heat-treating the freshly prepared nonwoven sample at 90°C for 10 seconds in an oven, the height of the upper and lower parts of the nonwoven under recovery conditions is measured according to the height test.

[0117] (3) Shape Memory Index

[0118] When the upper or lower part has a fresh height and a recovered height greater than 0.2 mm, the shape memory index is calculated according to the following equation (I). The upper or lower part is considered to have no shape memory effect, and the shape memory index is 100.

[0119] Shape memory index = (recovery height / fresh height) × 100 (I)

[0120] When the upper or lower part has a fresh height and recovery height of no more than 0.2 mm, the upper or lower part is considered to have no shape memory effect and has a 100% shape memory index.

[0121] 3. Three-dimensional appearance test

[0122] The three-dimensional appearance of the first side of the nonwoven fabric is evaluated into the following three categories.

[0123] Defect: The three-dimensional appearance is not obvious or unsatisfactory.

[0124] Good: The three-dimensional appearance looks comfortable and satisfactory.

[0125] Example

[0126] Example 1: Nonwoven Fabric Preparation

[0127] Nonwoven fabrics 1-9 are produced using the various first and second fiber webs shown in Table 1. For each of nonwoven fabrics 1-5 and 7-9, a composite nonwoven fiber web is manufactured by laying the first fiber web onto a conveyor belt and covering it with a second fiber web using a parallel carding machine. For nonwoven fabric 7, a composite nonwoven fiber web is manufactured by laying the first fiber web onto a conveyor belt and covering it with a spunbond fiber web as the second fiber web. Each composite nonwoven fiber web is heat-treated at a temperature of 130°C-140°C using a conventional hot-ventilated heat treatment apparatus to produce a precursor nonwoven fabric. The precursor nonwoven fabric is then subjected to a mechanical perforation process involving a pair of rollers to produce a three-dimensional or two-dimensional nonwoven fabric.

[0128] Example 2. Nonwoven fabric properties

[0129] The nonwoven fabric was evaluated as described below. The shape memory index was obtained according to the shape memory index test and height test disclosed herein. Microscopic images were taken at a magnification of 20×.

[0130] Figure 13 The image is a microscopic image of a cross-section of nonwoven fabric 4, showing the upper height 22h and lower height 24h under fresh conditions, wherein the upper height 22h is 0.592 mm and the lower height 24h is 0.735 mm. Figure 14 The image is a microscopic image of a cross-section of nonwoven fabric 4, showing the upper height 22h and lower height 24h under recovery conditions, wherein the upper height 22h is 0.824 mm and the lower height 24h is 1.215 mm.

[0131] Figure 15 The image is a microscopic image of a cross-section of the nonwoven fabric 7, showing the upper height 22h and the lower height 24h under fresh conditions, wherein the upper height 22h is 0.520 mm and the lower height 24h is 0.114 mm. Figure 16 The image is a microscopic image of a cross-section of the nonwoven fabric 7, showing the upper height 22h and the lower height 24h under recovery conditions, wherein the upper height 22h is 0.886 mm and the lower height 24h is 0.162 mm.

[0132] Based on the three-dimensional appearance test disclosed in this paper, four groups were used to evaluate the three-dimensional appearance of the nonwoven fabric. All results are shown in Table 1 below.

[0133] Table 1

[0134]

[0135]

[0136] All PET / PE fibers: ETC323, JNC Corporation, China

[0137] All PP / PE fibers: TA21, Jiangnan Fiber, China

[0138] All PET fibers: YZW122, Yizheng Chemical Fiber, China

[0139] Table 1 (continued)

[0140]

[0141] PE / PP spunbond * Pegas Nonwoven, Czech Republic

[0142] Nonwoven fabrics 3 and 6-8

[0143] Nonwovens 9

[0144] The dimensions and values ​​disclosed herein should not be construed as strictly limited to the precise numerical values ​​cited. Rather, unless otherwise specified, each such dimension is intended to represent the stated value and a range around which it is functionally equivalent. For example, a dimension disclosed as “40 mm” is intended to represent “approximately 40 mm”.

[0145] Unless expressly excluded or otherwise limited, every reference cited herein, including any cross-references or related patents or applications, is incorporated herein by reference in its entirety. Reference to any reference is not an endorsement of its existence as prior art to any disclosed or protected art herein, nor is it an endorsement of any such invention, either on its own or in combination with any one or more references. Furthermore, where any meaning or definition of a term in this invention conflicts with any meaning or definition of the same term in referenced documents, the meaning or definition given to that term in this invention shall prevail.

[0146] While specific embodiments of the invention have been illustrated and described by way of example, it will be apparent to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, it is intended that all such changes and modifications falling within the scope of the invention be covered by the appended claims.

Claims

1. An absorbent article comprising a skin-facing surface, a clothing-facing surface, a liquid-permeable topsheet, a liquid-impermeable backsheet, an absorbent structure disposed between the topsheet and the backsheet, and a three-dimensional nonwoven fabric. The three-dimensional nonwoven fabric includes: First side view, Second side, A protruding first region, the protruding first region comprising an upper portion in the first side and a lower portion in the second side, and The second region, which includes multiple deformations, and The shape memory index of the upper part is higher than that of the lower part. The shape memory index is calculated according to the following formula: Shape memory index = (recovery height / fresh height) × 100 The test methods and conditions for shape memory index, recovered height, and fresh height are as defined in the height measurement and shape memory index test. The protruding first region is filled with fibers.

2. The absorbent article of claim 1, wherein the three-dimensional nonwoven fabric comprises a plurality of the first regions, each of the first regions being substantially surrounded by the second region.

3. The absorbent article according to claim 1 or 2, wherein the upper part has a shape memory index of not less than 120% as measured by a shape memory index test.

4. The absorbent article according to claim 1 or 2, wherein the lower portion has a shape memory index of less than 120% as measured by a shape memory index test.

5. The absorbent article according to claim 1 or 2, wherein the first region has an upper height of not less than 0.80 mm as measured by a height test.

6. The absorbent article according to claim 1 or 2, wherein the first region has a lower height that is not greater than the upper height as measured by a height test.

7. The absorbent article according to claim 1 or 2, wherein the lower part height is not greater than 0.2 mm.

8. The absorbent article according to claim 1 or 2, wherein the deformation is a hole, a recess or a combination thereof, and is formed from the first side side toward the second side side.

9. The absorbent article according to claim 6, wherein the second region includes at least one deformation, the at least one deformation having at least three adjacent deformations, wherein each of the one deformation and the at least three adjacent deformations has an edge-to-edge spacing of not more than 3 mm.

10. The absorbent article according to claim 1 or 2, wherein the first region is filled with fibers.

11. The absorbent article according to claim 1 or 2, wherein the upper portion comprises fibers, the fibers comprising polymers selected from the group consisting of: polyethylene terephthalate, polyethylene terephthalate, polybutene, polyethylene terephthalate copolymers, poly(tetramethylene ether) glycol, and combinations thereof.

12. The absorbent article of claim 1 or 2, wherein the top sheet comprises the three-dimensional nonwoven fabric such that the first side surface of the three-dimensional nonwoven fabric forms at least a portion of the skin-facing surface.

13. The absorbent article according to claim 1 or 2, wherein the absorbent article comprises an outermost layer, the outermost layer comprising the three-dimensional nonwoven fabric such that the first side surface of the three-dimensional nonwoven fabric forms at least a portion of the surface facing the garment.

14. The absorbent article according to claim 1 or 2, wherein the upper portion of the first side surface is protruding.

15. The absorbent article according to claim 1 or 2, wherein the lower portion of the second side surface is not recessed.

16. A three-dimensional nonwoven fabric, the three-dimensional nonwoven fabric comprising a first side surface, a second side surface, a protruding first region and a second region, the protruding first region comprising an upper portion in the first side surface and a lower portion in the second side surface, the second region comprising multiple deformations, The shape memory index of the upper part is higher than that of the lower part. The shape memory index is calculated according to the following formula: Shape memory index = (recovery height / fresh height) × 100 The test methods and conditions for shape memory index, recovered height, and fresh height are as defined in the height measurement and shape memory index test. The protruding first region is filled with fibers.

17. The three-dimensional nonwoven fabric of claim 16, wherein the three-dimensional nonwoven fabric comprises a plurality of the first regions, each of the first regions being substantially surrounded by the second region.

18. The three-dimensional nonwoven fabric according to claim 16 or 17, wherein the upper portion has a shape memory index of not less than 120% as measured by a shape memory index test.

19. The three-dimensional nonwoven fabric according to claim 16 or 17, wherein the lower portion has a shape memory index of less than 120% as measured by a shape memory index test.

20. The three-dimensional nonwoven fabric according to claim 16 or 17, wherein the first region has an upper height of not less than 0.80 mm as measured by a height test.

21. The three-dimensional nonwoven fabric according to claim 16 or 17, wherein the lower part height is not greater than 0.2 mm.

22. The three-dimensional nonwoven fabric according to claim 16 or 17, wherein the deformation is a hole, a recess, or a combination thereof, and is formed from the first side toward the second side.

23. The three-dimensional nonwoven fabric according to claim 16 or 17, wherein the second region includes at least one deformation, the at least one deformation having at least three adjacent deformations, wherein each of the one deformation and the at least three adjacent deformations has an edge-to-edge spacing of not more than 3 mm.

24. The three-dimensional nonwoven fabric according to claim 16 or 17, wherein the first region is filled with fibers.

25. The three-dimensional nonwoven fabric according to claim 16 or 17, wherein the upper portion comprises fibers, the fibers comprising polymers selected from the group consisting of polyethylene terephthalate, polypropylene terephthalate, and combinations thereof.

26. The three-dimensional nonwoven fabric according to claim 16 or 17, wherein the upper portion of the first side surface is protruding.

27. The three-dimensional nonwoven fabric according to claim 16 or 17, wherein the lower portion of the second side surface is not recessed.

Images