Hydraulically patterned nonwovens and methods of making the same

Abstract

A method of forming a hydroentangled nonwoven web, the method comprising the steps of forming a nonwoven batt comprising continuous spunmelt fibers, calender bonding the nonwoven batt to form a thermally bonded precursor nonwoven web having a bond pattern, the bond pattern defining bond impressions and unbonded areas between the bond impressions; and hydroentangling the thermally bonded precursor nonwoven by a plurality of water jet steps as the thermally bonded nonwoven web is passed through a screen. The bond pattern has particular features that provide advantages in the mechanical properties and visual appearance of the final nonwoven product.

Description

[0001] Related applications

[0002] This application claims priority and interest in U.S. Provisional Application No. 63 / 183,148, filed May 3, 2021, entitled “HYDRO-PATTERNED NONWOVEN AND METHOD OF MAKING THE SAME,” the contents of which are incorporated herein by reference in their entirety. Invention Field

[0003] The present invention relates to hydraulically patterned nonwovens and an improved method for manufacturing hydraulically patterned nonwovens, wherein the nonwovens are given an adhesive pattern before being subjected to hydraulic treatment. Background of the Invention

[0005] Melt-spun nonwovens (such as spunbond nonwovens, meltblown nonwovens, and combinations thereof) are formed from thermoplastic continuous fibers such as polypropylene (PP), polyethylene terephthalate (PET), bicomponent or multicomponent fibers, and mixtures of such melt-spun fibers with rayon, cotton, and cellulose pulp fibers. Typically, melt-spun nonwovens achieve a bond that is substantially brittle and retains its properties through post-bonding processing and transformation, via thermal bonding, ultrasonic bonding, chemical bonding (e.g., via latex), or resin bonding. Thermal bonding and ultrasonic bonding produce permanent fusion, while chemical bonding may or may not produce permanent bonding.

[0006] It is known to apply hydraulic treatments to improve fabric properties, such as softness or bulkiness. A known hydraulic treatment method called hydroengorgement is described, for example, in U.S. Patent Nos. 7,858,544 and 10,767,296. Numerous methods for forming pores in nonwoven webs using different techniques are also known.

[0007] There is a need for a method to form a hydromimetic nonwoven fabric from a thermally bonded precursor web, which results in a combination of improved properties in the product, such as softness, abrasion resistance, and tensile strength. Summary of the Invention

[0008] A method for forming a hydraulically patterned nonwoven web according to an exemplary embodiment of the present invention includes: forming a nonwoven mat comprising continuous melt-spun fibers; calendering and bonding the nonwoven mat to form a thermally bonded precursor nonwoven web having a bonding pattern defining bonding indentations and unbonded areas between the bonding indentations; and hydraulically treating the thermally bonded precursor nonwoven web by a plurality of water jetting steps as the thermally bonded nonwoven web passes through a screen, wherein the bonding pattern has a bonding area percentage of 10% to 25%, an imaginary circle C is defined as the largest circle whose perimeter can be drawn between the unbonded areas and has a perimeter intersecting a single point on the perimeter of each of at least two adjacent bonding indentations within the bonding pattern, and the circle C has a radius of at least 0.5 mm, preferably at least 1.0 mm, more preferably at least 1.5 mm, and even more preferably at least 2.0 mm in the unbonded areas, and the bonding pattern includes bonding indentation areas of at least 1 mm². 2 Large, bold adhesive indentations.

[0009] In an exemplary embodiment, the step of forming the precursor web includes the melt-spun fibers of the nonwoven wadding composed of spunbond filaments.

[0010] In an exemplary embodiment, the step of forming the precursor web includes the nonwoven wadding comprising two or more layers.

[0011] In an exemplary embodiment, the melt-spun fibers in each of the two or more layers comprise spunbond filaments.

[0012] In an exemplary embodiment, the average fiber thickness difference between the layers is less than 20%, preferably less than 15%, more preferably less than 10%, and even more preferably less than 5%.

[0013] In an exemplary embodiment, at least one of the two or more layers comprises spunbond filaments, and at least one other layer comprises meltblown fibers.

[0014] In an exemplary embodiment, the at least one layer comprising spunbond filaments forms at least one outer layer of the nonwoven wadding.

[0015] In an exemplary embodiment, the two or more layers include at least three layers forming a spunbond-meltblown-spunbond (SMS) structure.

[0016] In an exemplary embodiment, the method further includes a step of applying at least one layer formed of fibers and / or particles to a fully bonded nonwoven precursor web prior to the hydraulic treatment step.

[0017] In an exemplary embodiment, the fiber is a short synthetic fiber, preferably a polyester-based short fiber or viscose fiber.

[0018] In an exemplary embodiment, the fiber is a natural fiber, preferably cotton fiber, pulp, or modified cellulose such as rayon.

[0019] In an exemplary embodiment, the step of forming the precursor web includes the continuously melt-spun fibers, which comprise polyolefins or polyamides or polyesters or polysaccharide homopolymers, copolymers or polymer blends.

[0020] In an exemplary embodiment, the step of forming the precursor web includes the continuous melt-spun fibers, which include polypropylene, polyethylene, polylactic acid, polyhydroxyalkanoates, polyhydroxybutyrate, polybutylene succinate, polyethylene terephthalate, thermoplastic starch, copolymers thereof, copolymers thereof with olefins, esters, amides or other polymers, or blends thereof.

[0021] In an exemplary embodiment, the step of forming the precursor web includes the melt-spun fibers comprising a multi-component, preferably bi-component, continuous melt-spun fiber.

[0022] In an exemplary embodiment, the component polymer composition present in at least 40% of the surface of each filament, preferably at least 50% of the surface of each filament, more preferably at least 60% of the surface of each filament, and even more preferably covering the entire surface of each filament, has a lower melting temperature than the melting temperature of at least one other component polymer composition, preferably at least 2°C, more preferably at least 5°C.

[0023] In an exemplary embodiment, the step of forming the precursor web includes the melt-spun fiber, which comprises a bicomponent core-sheath continuous melt-spun fiber having a core comprising polypropylene and a sheath comprising a blend of polypropylene and a polypropylene-polyethylene copolymer.

[0024] In an exemplary embodiment, the continuously melt-spun fiber contains additives.

[0025] In an exemplary embodiment, the additive includes additives selected from the following types: coloring pigments, softening enhancers, slip agents, fillers, and combinations thereof.

[0026] In an exemplary embodiment, the step of forming the precursor mesh includes having an adhesive indentation area of ​​less than 1 mm². 2 The adhesive pattern with small adhesive indentations.

[0027] In an exemplary embodiment, the step of forming the precursor mesh includes the circle C having a radius of at least 1 mm, preferably at least 2 mm, more preferably at least 3 mm, and even more preferably at least 4 mm.

[0028] In an exemplary embodiment, the step of forming the precursor mesh includes a minimum distance between adjacent adhesive indentations of at least 0.3 mm, preferably at least 0.4 mm, and most preferably at least 0.5 mm.

[0029] In an exemplary embodiment, the step of forming the precursor mesh includes the adhesive indentation having a line shape of constant width, with a line width (W) of up to 0.6 mm, preferably up to 0.5 mm, and most preferably up to 0.4 mm.

[0030] In an exemplary embodiment, the step of forming the precursor mesh includes the adhesive indentation having the shape of a line with an irregular width, with a maximum line width (W) of 0.6 mm, preferably 0.5 mm, and most preferably 0.4 mm.

[0031] In an exemplary embodiment, the step of forming the precursor mesh includes the adhesive indentation having a line shape and the adhesive indentation having an adhesive shape perimeter including at least one convex portion.

[0032] In an exemplary embodiment, the step of forming the precursor mesh includes the adhesive indentation having the shape of a continuous line.

[0033] In an exemplary embodiment, the step of forming the precursor mesh includes the adhesive indentation having the shape of a line with a length (L) of up to 30 mm, preferably up to 25 mm, and more preferably up to 20 mm.

[0034] In an exemplary embodiment, the step of forming the precursor mesh includes including an adhesive indentation area equal to or greater than 1 mm². 2 The adhesive pattern is defined by large, bold adhesive indentations.

[0035] In an exemplary embodiment, the hydraulic treatment step includes applying water pressure to the nonwoven precursor web using a water jet.

[0036] In an exemplary embodiment, the hydraulic treatment step includes applying water pressure to the nonwoven precursor web via at least two sets of water jets.

[0037] In an exemplary embodiment, the method is performed at a linear velocity of at least 150 m / min.

[0038] In an exemplary embodiment, the linear velocity is 450 m / min or less.

[0039] The hydraulically patterned nonwoven web according to an exemplary embodiment of the present invention is produced by a method including any of the steps described above.

[0040] In an exemplary embodiment, the hydraulically patterned nonwoven web has a basis weight of 60 gsm or less, preferably 50 gsm or less, more preferably 45 gsm or less, and even more preferably 35 gsm or less.

[0041] In an exemplary embodiment, the hydraulically patterned nonwoven web has a tensile strength of at least 4 N / cm.

[0042] In an exemplary embodiment, the hydraulically patterned nonwoven web has a CD tensile strength of at least 2 N / cm.

[0043] In an exemplary embodiment, the hydraulically patterned nonwoven web has a thickness (caliper) of at least 10 micrometers / gsm fabric, preferably at least 11 micrometers / gsm fabric, and most preferably at least 12 micrometers / gsm fabric.

[0044] In an exemplary embodiment, the hydraulic treatment step includes applying water pressure to the nonwoven precursor web through more than one set of water jets, each set of water jets applying a pressure greater than that applied by a set of water jets preceding that set of water jets in the machine direction.

[0045] In an exemplary embodiment, the more than one set of water jets includes a first set of water jets, a second set of water jets positioned in the machine direction preceding the first set of water jets, and a third set of water jets positioned in the machine direction preceding the first and second sets of water jets. The second set of water jets applies a pressure of 80% to 95% of the pressure applied by the first set of water jets. The third set of water jets applies a pressure of 64% to 90% of the pressure applied by the second set of water jets.

[0046] In an exemplary embodiment, the hydraulic treatment step includes at least partially altering each adhesive indentation by applying water pressure.

[0047] In an exemplary embodiment, the at least partially modified step results in at least 60% of the fully bonded portion of each adhesive indentation being retained after the hydraulic application step.

[0048] In an exemplary embodiment, the at least partially modified step results in at least 70% of the fully bonded portion of each adhesive indentation being retained after the hydraulic application step.

[0049] In an exemplary embodiment, the at least partially modified step results in at least 80% of the fully bonded portion of each adhesive indentation being retained after the hydraulic application step.

[0050] In an exemplary embodiment, the at least partially modified step results in at least 90% of the fully bonded portion of each adhesive indentation being retained after the hydraulic application step.

[0051] In an exemplary embodiment, the at least partially altered step results in each adhesive indentation being divided into at least two parts.

[0052] In an exemplary embodiment, the at least partially altered step causes fibers in the region surrounding the perimeter of each adhesive indentation to randomly grind into and out of the main plane of the fully bonded precursor nonwoven web, so as to at least partially eliminate the three-dimensionality of each adhesive indentation.

[0053] A method for forming a hydromimetic patterned nonwoven web according to an exemplary embodiment of the present invention includes: forming a nonwoven mat comprising continuous melt-spun fibers; calendering and bonding the nonwoven mat to form a thermally bonded precursor nonwoven web having a bonding pattern defining bonding indentations and unbonded areas between bonding indentations; and hydrotreating the thermally bonded precursor nonwoven web by a plurality of water jetting steps as the thermally bonded nonwoven web passes through a screen, wherein the bonding pattern has a bonding area percentage of 10% to 25%, and the bonding pattern includes bonding indentation areas of less than 1 mm². 2 Small adhesive indentations, and the adhesive pattern includes adhesive indentations with an area of ​​at least 1 mm. 2 Large adhesive indentations.

[0054] A method for forming a hydraulically patterned nonwoven web according to an exemplary embodiment of the present invention includes: forming a nonwoven mat comprising continuous melt-spun fibers; calendering and bonding the nonwoven mat to form a thermally bonded precursor nonwoven web having a bonding pattern defining bonding indentations and unbonded areas between bonding indentations; and hydraulically treating the thermally bonded precursor nonwoven web by a plurality of water-jet steps as the thermally bonded nonwoven web passes through a screen, wherein the regular bonding pattern has a bonding area percentage of 10% to 25%, and the bonding pattern formed in the calendering and bonding steps includes bonding indentations with an area of ​​at least 1 mm². 2 The large adhesive indentation has a line shape with an irregular width, a maximum line width (W) of 0.6 mm, preferably 0.5 mm, and most preferably 0.4 mm, and the adhesive indentation has a line shape with a length (L) of up to 30 mm, preferably up to 25 mm, and more preferably up to 20 mm. Attached Figure Description

[0055] The above and related objects, features, and advantages of the invention will be more fully understood when taken in conjunction with the accompanying drawings and by referring to the following detailed description of preferred (albeit illustrative) embodiments of the invention, wherein:

[0056] Figure 1 This is a representative diagram of a system for forming a hydraulically patterned nonwoven web according to an exemplary embodiment of the present invention;

[0057] Figure 2A and Figure 2B This is a representative diagram of a system for forming a hydraulically patterned nonwoven web according to an exemplary embodiment of the present invention;

[0058] Figure 3A , Figure 3B , Figure 3C and Figure 3D An adhesive pattern is shown that can be used to form a hydraulically patterned nonwoven web according to an exemplary embodiment of the invention;

[0059] Figure 4A An adhesive pattern is shown that can be used to form a hydraulically patterned nonwoven web according to an exemplary embodiment of the invention;

[0060] Figure 4B An adhesive pattern of 4A on the precursor mesh is shown according to an exemplary embodiment of the present invention;

[0061] Figure 5 An adhesive pattern is shown that can be used to form a hydraulically patterned nonwoven web according to an exemplary embodiment of the invention;

[0062] Figure 6A An adhesive pattern is shown that can be used to form a hydraulically patterned nonwoven web according to an exemplary embodiment of the invention;

[0063] Figure 6B An adhesive pattern of 6A on the precursor mesh is shown according to an exemplary embodiment of the present invention;

[0064] Figure 7A An adhesive pattern is shown that can be used to form a hydraulically patterned nonwoven web according to an exemplary embodiment of the invention;

[0065] Figure 7B An adhesive pattern of 7A on a precursor mesh according to an exemplary embodiment of the present invention is shown;

[0066] Figure 8A An adhesive pattern is shown that can be used to form a hydraulically patterned nonwoven web according to an exemplary embodiment of the invention;

[0067] Figure 8B An adhesive pattern of 8A on a precursor mesh according to an exemplary embodiment of the present invention is shown;

[0068] Figure 9 An adhesive pattern is shown that can be used to form a hydraulically patterned nonwoven web according to an exemplary embodiment of the invention;

[0069] Figure 10A An adhesive pattern is shown that can be used to form a hydraulically patterned nonwoven web according to an exemplary embodiment of the invention;

[0070] Figure 10B An adhesive pattern of 10A on a precursor mesh according to an exemplary embodiment of the present invention is shown;

[0071] Figure 11 Table 1 is provided, which includes certain features of various bonding patterns that can be used in methods for forming hydraulically patterned nonwoven webs according to exemplary embodiments of the present invention;

[0072] Figure 12A These are photomicrographs of bonding patterns on a precursor fabric according to an exemplary embodiment of the present invention;

[0073] Figure 12B It is an exemplary embodiment of the present invention by Figure 12A Micrographs of hydro-patterned nonwoven webs formed from precursor fabrics;

[0074] Figure 13 This is a perspective view of the grading scale used for napping assessment in the Martindale Average Abrasion Rating Test;

[0075] Figure 14 It is the Martindale wear test method grade scale;

[0076] Figures 15A to 15D The cross-sectional variations of each adhesive indentation produced by the method of an exemplary embodiment of the present invention are shown;

[0077] Figure 15E and Figure 15F These are micrographs showing the cross-sectional variations of various bond indentations produced by conventional hydraulic treatment processes; and

[0078] Figure 16A and Figure 16B Plan views of a patterned nonwoven web before and after hydraulic treatment according to an exemplary embodiment of the present invention are shown. Detailed Implementation

[0079] This invention relates to improved techniques for hydraulically treated nonwoven fabrics and nonwoven fabrics manufactured using these methods. The hydraulically treated fabrics described herein are referred to as "hydraulically patterned" fabrics.

[0080] The nonwoven fabrics hydraulically treated according to the present invention are applicable to disposable absorbent articles. As used herein, the term "absorbent article" refers to an article that absorbs and contains fluid and solid materials. For example, absorbent articles can be placed against or near the body to absorb and contain various exudates discharged from the body. Absorbent articles can be wearable articles, such as baby diapers, adult incontinence products, and feminine care products, or hygiene products for absorbing fluid and solid materials, such as medical professional products for use with products such as disposable gowns and clamps. In particular, nonwoven fabrics according to exemplary embodiments of the present invention can be used as a body contact layer (e.g., a top sheet) of an absorbent article or as part of a body contact layer of an absorbent article, or for forming other components of the absorbent article, such as a backing sheet, waistband, or fastening sheet. Nonwoven fabrics according to exemplary embodiments of the present invention can also be used to package or encapsulate articles such as absorbent articles. The term "disposable" is used herein to describe absorbent articles that are not intended to be washed or otherwise recovered or reused as absorbent articles, but are intended to be discarded after a single use and are preferably recyclable, compostable, or otherwise disposed of in an environmentally compatible manner.

[0081] The term “disposable” is used herein to describe absorbent articles that are not intended to be washed or otherwise restored or reused as absorbent articles, but are intended to be discarded after a single use and are preferably recyclable, compostable or otherwise disposed of in an environmentally compatible manner.

[0082] Unless otherwise stated, the terms “fiber” and “filament” are used interchangeably in this application (e.g., “endless filament” or “short fiber”, etc.).

[0083] As used herein, the term "floc" refers to fibrous material before it is bonded together. A "floc" comprises individual fibers that are typically not bonded to each other, although a certain amount of pre-bonding may occur between the fibers, and this pre-bonding can occur, for example, during or shortly after fiber placement in a melt spinning process. However, this pre-bonding still allows a considerable amount of fiber free movement, enabling them to be repositioned. A "floc" may comprise several layers, produced by depositing fibers from several spinnerets in a melt spinning process, and the distribution of fiber diameter thickness and porosity in the "sub-layers" placed from each spinneret does not differ significantly. Adjacent fiber layers do not need to be separated from each other by abrupt changes, and the individual layers can be partially mixed in the region surrounding the boundary.

[0084] As used herein, the terms "nonwoven fabric, nonwoven textile, sheet, or web" refer to sheets or webs made of oriented or randomly oriented fibers or filaments, which first form pads, then one or more pads are stacked on top of each other and bonded together by friction, cohesion, adhesion, or one or more bonding patterns and by bonding indentations created by localized compression and / or application of pressure, heat, ultrasound, or thermal energy, or combinations thereof. This term does not include fabrics woven, knitted, or sewn with yarns or filaments. Fibers can be natural or man-made, and can be short fibers or continuous filaments or in-situ formed. Commercially available fibers have diameters from about 0.0005 mm to about 0.25 mm, and they come in several different forms: short fibers (called staple fibers or chopped fibers), continuous monofilaments (filaments or monofilaments), untwisted dies (yarns) of continuous filaments, and twisted dies (yarns) of continuous filaments. Nonwoven fabrics can be formed by a variety of methods, including but not limited to meltblowing, spunbonding, melt spinning, solvent spinning, electrospinning, carding, membrane fibrillation, melt-film fibrillation, air-laid web formation, dry web formation, wet web formation with short fibers, and combinations of these methods, as known in the art. The basis weight of nonwoven fabrics is typically expressed in grams per square meter (gsm).

[0085] The term "melt-spun fiber" refers to fibers formed by heating a thermoplastic polymer (e.g., polypropylene, polyester, or nylon) and extruding it through a metal plate (called a spinneret or die) with hundreds of holes therein. Examples of melt-spun fibers include spunbond fibers and meltblown fibers. Melt-spun fibers can be monocomponent, formed from a single polymer component or a single blend of polymer components; or they can be multicomponent, wherein the cross-section of each fiber comprises at least two discrete polymer components or blends of polymer components, or at least one discrete polymer component and at least one discrete blend of polymer components. Fibers having two discrete components can be referred to as bicomponent fibers.

[0086] A web or fabric made of melt-spun fibers can be called a "melt-spun web or fabric".

[0087] As used herein, the term "spunbond fiber" refers to a substantially continuous fiber or filament having an average diameter of 10-30 micrometers. It also includes splittable bicomponent or multicomponent fibers with an average diameter of 10-30 micrometers before splitting.

[0088] As used in this article, “meltblown fiber” refers to a substantially continuous fiber or filament having an average diameter of less than 10 micrometers.

[0089] As used herein and understood by those skilled in the art, the term "fully bonded nonwoven fabric" refers to a nonwoven fabric having fibers that are fused together with each other via a bonding indentation that has been melted and cured. Such fabrics can be used in a variety of applications, such as conversion into diapers, or as precursors for further processing (e.g., hydrophilic spinning oiling or hydroponic treatment). For example, a fully calendered bonded nonwoven fabric can be produced by passing a wadding under pressure through a gap between two heated rollers, thereby providing a pattern of fusion embossed indentations in the fabric. The pressure and temperature within the gap are sufficient to soften and melt the individual fibers, which are then fused together using a raised pattern on at least one heated roller to create a series of fusion indentations in which most of the fibers within the fusion indentations can no longer be distinguished as individual fibers. The bonding indentation results in the fusion of the fibers, or, in the case of bicomponent fibers, the fusion of at least one component with the lowest melting temperature across the entire thickness of the fabric. The roller temperature and pressure are adjusted according to the fabric formulation and basis weight. For example, 100% polypropylene spunbond fabrics of 20-25 gsm are typically bonded at roller temperatures >150°C and gap pressures greater than 90 N / mm. Temperature / pressure settings are adjusted to handle different basis weights and / or linear speeds. Higher basis weights and / or linear speeds may require increased gap pressures and / or temperatures to obtain “fully” bonded fabrics with fusion bond points. It should be understood that, for the purposes of this disclosure, viscous bonding is not within the definition of “fully bonded.”

[0090] As used herein, the term “bonded area percentage” refers to the ratio of the area occupied by the bonded indentation to the total surface area of ​​the nonwoven fabric, expressed as a percentage and measured according to the bonded area percentage method described herein.

[0091] Regarding the manufacture of nonwoven web materials and the nonwoven web materials themselves, the "transverse direction" (CD) refers to the direction along the web material that is substantially perpendicular to the direction of forward travel of the web material through the production line that manufactures the web material. Regarding the movement of the wadding through the gap between a pair of calendering rollers to form the bonded nonwoven web, the transverse direction is perpendicular to the direction of movement through the gap and parallel to the gap.

[0092] Regarding the manufacture of nonwoven web materials and the nonwoven web material itself, "machine direction" (MD) refers to the direction along the web material that is substantially parallel to the direction of forward travel of the web material through the production line that manufactures the web material. Regarding the nonwoven wadding that moves through the gap between a pair of calendering rollers to form a bonded nonwoven web, the machine direction is parallel to the direction of movement through the gap and perpendicular to the gap.

[0093] A "bonding protrusion" or "protrusion" is a feature of the bonding roll that is surrounded by a recessed area at its outermost radial portion. The bonding protrusion, relative to the axis of rotation of the bonding roll, comprises a radially outermost bonding surface having a bonding surface shape and a region of that shape, which is typically laid along an outer cylindrical surface having a substantially constant radius from the axis of rotation of the bonding roll; however, the radius of the protrusion with a discrete and separate shape relative to the bonding roll is typically small enough that the bonding surface can appear flat / planar; and the bonding surface shape region approximates a planar region of the same shape. The bonding protrusion may have sides perpendicular to the bonding surface, although the sides typically have sloping bevels such that the cross-section of the base of the bonding protrusion is larger than its bonding surface. Multiple bonding protrusions may be arranged in a pattern on the calender roll. The multiple bonding protrusions have a bonding area per unit surface area of ​​the outer cylindrical surface, which can be expressed as a percentage, and the percentage per unit surface area of ​​the outer cylindrical surface is the ratio of the sum of the bonding shape areas of the protrusions within the unit to the total surface area of ​​the unit.

[0094] In nonwoven fabrics, "bonding indentations" or "fusion bonding indentations" are surface structures created by indentations from bonding protrusions on calender rolls. Bonding indentations are locations of deformed, interlocking, or entangled material from fibers that are molten or thermally fused beneath the bonding protrusions in the z-direction, forming a bonded or bonded area. Individual bonds in a nonwoven structure can be joined by loose fibers between them. The shape and size of the bonding indentations generally correspond to the shape and size of the bonding surface of the bonding protrusions on the calender rolls. For the purposes of this document, "bonding indentation thickness" should be understood as referring to the width of the bonding indentation area in the plane of the nonwoven fabric. One or two rolls may have their circumferential surfaces machined, etched, engraved, or otherwise shaped to have a bonding pattern with bonding protrusions and recessed areas, such that the bonding pressure applied to the padding at the seams is concentrated at the bonding surface of the bonding protrusions and reduced or substantially eliminated at the recessed areas. The bonding surface has a bonding surface shape. Therefore, an indentation pattern is formed on the nonwoven web to bond the fibers forming the web. This pattern has bonding indentations and bonding shapes that correspond to the pattern of bonding protrusions and the shape of the bonding surface on the bonding roller. A repeating pattern of bonding protrusions and recessed areas can be formed on the bonding roller. The bonding shapes depict the raised surfaces of the bonding protrusions on the roller, while the areas between them represent recessed areas. During calendering, the bonding shapes of the bonding protrusions press similarly shaped bonding indentations onto the web.

[0095] The term "decrease" in mechanical properties, tensile strength, abrasion rating, etc., as used in this article refers to the difference in fabric properties before and after the hydropatching process, and can be calculated using the formula [(value of final hydropatched fabric property) - (value of precursor property)] / (value of precursor property), where all values ​​are expressed in the same units. The decrease can be positive (an increase in value during hydropatching) or negative (a decrease in value during hydropatching), and can be expressed as a ratio (unitless) or percentage. For example, the decrease in MD tensile strength is calculated using the following formula: [(MD tensile strength of final hydropatched fabric) - (MD tensile strength of precursor)] / (MD tensile strength of precursor).

[0096] Figure 1 This is a block diagram showing various components used in a process for manufacturing a patterned nonwoven web according to an exemplary embodiment of the present invention. Although Figure 1 The method shown produces a nonwoven web with an SMS structure (2; 3; 4). It should be understood that this method can be reconfigured to form many other web structures including one or more spunbond layers and / or one or more meltblown layers, such as fabrics with single or multiple spunbond layers, more specifically S, SS, SSS, etc.; fabrics with a combination of spunbond and meltblown layers, typically having a spunbond layer forming at least one outer surface of the fabric, more specifically examples of asymmetric compositions are SSMS, SMSSMMS, SSMMS, SMMMSS, etc., or symmetric examples are SMS, SMMS, SMMMS, SSMSS, etc.; fabrics combining meltblown layers with other layers, more specifically examples being combinations of meltblown layers formed from endless filaments with short fibers formed from natural materials, etc. Nonwoven web structures are not limited to the examples provided herein, and those skilled in the art will understand that many other such structures can be obtained by changing the number and arrangement of process components.

[0097] Generally, it should be understood that the number and structure of the spunbond dies are not limited to those shown and described herein, and in other exemplary embodiments, the number and structure of the dies can vary to achieve different web structures. For example, a single spunbond die can be used to form a nonwoven wadding 6 on a conveyor belt 8 having a single spunbond layer, or multiple spunbond dies can be used to form a wadding 6 with a multi-spunbond layer structure, such as SS, SSS, SSSS, etc. The layers formed by multiple dies can be identical or very similar to each other in terms of filament type, process parameters, etc., such that the layers are substantially indistinguishable from each other, thus forming an article that appears to be a single-layer structure, or they can be produced differently from each other, thus forming a distinctly layered nonwoven product.

[0098] In another exemplary embodiment, only the spunbond die 2 and the meltblown die 3 are used to form the nonwoven mat 6 on the conveyor belt 8. According to another exemplary embodiment of the invention, multiple elements corresponding to the dies 2 and 3 can be combined in the system to form a mat 6 with multiple corresponding layers, such as SM, SMM, SSM, SSMM, etc. Similarly, the layers formed by multiple dies can be the same or very similar to each other in terms of filament type, process parameters, etc., making the layers substantially indistinguishable from each other, thus forming something that appears to be a single-layer structure, or they can be produced differently from each other, thus forming a distinctly layered nonwoven product.

[0099] According to an exemplary embodiment of the invention, the melt-spun nonwoven mat 6 is made of continuous filaments laid out in a random distribution on a moving conveyor belt 8. Resin particles can be processed into a melt under heating and then fed through spinnerets (or spinning dies 2 and 4) to produce hundreds of filaments by using a stretching device (not shown). Multiple spinnerets or dies (blocks in series) can be used to provide spunbond fibers with increased density, the spunbond fibers corresponding to, for example, each of spinning dies 2 and 4. A jet of fluid (e.g., air) causes the fibers from dies 2 and 4 to be elongated, and then the fibers are blown or conveyed onto a moving net (conveyor belt) 8, where they are laid out and attracted against the net 8 in a random pattern by an attraction box (not shown) to form the mat 6. Meltblown layers can preferably be deposited between the spunbond layers laid out by spinning dies 2 and 4 by a meltblown mechanism (or "die") 3. Meltblown ("MB") layers can be formed by a meltblown process, but can also be formed by a variety of other known processes. For example, a meltblown process involves inserting a thermoplastic polymer into a die. The thermoplastic polymer material is extruded through multiple fine capillaries in the die to form fibers. The fibers flow into a high-speed gas stream (e.g., air), which weakens the flow of molten thermoplastic polymer material to reduce their diameter, which may be the diameter of microfibers. The meltblown fibers are quasi-randomly deposited through a die 3 onto a moving web or a moving web having a spunbond layer laid through a spinning die 2 to form a meltblown layer. One, two, or more meltblown blocks can be used in series to increase fiber coverage. When the meltblown fibers are deposited, they can be sticky, which typically results in some adhesion between the meltblown fibers on the web.

[0100] In a preferred embodiment, the fibers used to form the fuzz 6 are thermoplastic polymers, examples of which include polyolefins (e.g., polypropylene "PP" or polyethylene "PE"), polyesters (e.g., polylactic acid "PLA" or polyhydroxyalkanoate "PHA" or polyhydroxybutyrate "PHB" or polybutylene succinate "PBS" or polyethylene terephthalate "PET"), polyamides, their polysaccharides (e.g., thermoplastic starch "TPS" or starch-based polymers), copolymers (with olefins, esters, amides, or other monomers), and blends thereof. Preferably, the fibers are made of polyolefins, examples of which include polyethylene, polypropylene, their propylene-butene copolymers, and blends thereof, including, for example, ethylene / propylene copolymers and polyethylene / polypropylene blends. Resins with higher crystallinity and lower elongation at break may also be suitable due to the possibility of easier breakage. The fibers may also be formed from, for example, non-oil-based components, such as aliphatic polyesters, thermoplastic polysaccharides, or other biopolymers, or they may contain these substances as additives or modifiers. As used herein, the term "blend" includes a homogeneous or semi-homogeneous mixture of at least two polymers.

[0101] Another method involves forming a nonwoven web of multicomponent or preferably “bicomponent” polymer fibers. Such bicomponent polymer fibers can be formed using a spinneret with two adjacent portions, representing a first component from one polymer or blend and a second component from another, to form fibers with the cross-section of the first component in one portion and the second component in the other (hence the term “bicomponent”). The components can be advantageously selected to have different melt temperatures and / or expansion-shrinkage rates. These different properties of the two polymers, when combined in side-by-side or asymmetrical sheath-core geometries, can cause the bicomponent fiber product to crimp during spinning as it cools and is pulled from the spinneret. The resulting crimped fibers can then be laid in a wadding and calendered in a patterned manner. The crimp in the fibers is thought to increase the bulk and nap of the web, enhancing the visual and tactile signals of softness.

[0102] In one exemplary embodiment, the wadding 6 can be thermo-calendered and bonded via rollers 10 and 12. One or both of rollers 10 and 12 may have circumferential surfaces that are machined, etched, engraved, or otherwise formed to have a pattern of raised and recessed areas, such that the bonding pressure applied to the wadding 6 at the seam is concentrated at the outward-facing surfaces of the raised areas and reduced or substantially eliminated at the recessed areas. According to an exemplary embodiment of the invention, roller 10 is a calendering roller, and roller 12 is a bonding roller defining the bonding pattern. The thermo-calendering produces a thermally bonded precursor web 7, preferably a fully bonded precursor web 7. Preferred bonding patterns according to an exemplary embodiment of the invention are further described below.

[0103] According to an exemplary embodiment of the invention, the precursor nonwoven web 7 is then hydraulically treated using one or more water jet injectors. Although Figure 1 Three water jets 16a, 16b, and 16c are shown; however, it should be understood that the method may include using only one jet. The one or more jets are included in a single water treatment station. According to an exemplary embodiment of the invention, as the pre-body nonwoven web 7 is conveyed below the jets 16a to 16c via belt 22, the high-pressure water jets of the water jets act on and pass through the fabric. Similarly, although... Figure 1 Water jets are shown, but it should be understood that the number of water jets is not limited to three, and any number and arrangement of water jets can be present to suit a particular production line. In exemplary embodiments, there may be one or more water jets, preferably two to six, and more preferably three to four.

[0104] The corresponding dewatering systems 20a, 20b, and 20c can be positioned below each ejector (group) 16a to 16c to draw water away and dry the precursor fabric 7. The dewatering systems 20a, 20b, and 20c may include, for example, a vacuum chamber, a suction chamber, a Uhle chamber, a fan, and / or a vacuum trough. The nonwoven precursor web 7 can then be dried by blowing hot air over the web, by using an IR dryer, or by other drying techniques (e.g., air drying).

[0105] According to an exemplary embodiment of the invention, the band 22 may be combined with one or more screens, each screen having a predetermined pattern for supporting the precursor nonwoven web 7, while being hydraulically treated by corresponding water jets 16a to 16c. See below for reference. Figure 2A and Figure 2B In further detail, one or more screens may be replaced by one or more rollers 14, and a roller or the last roller in a series of rollers may be provided with a sleeve 18.

[0106] According to an exemplary embodiment of the invention, one or more rollers are used, each associated with one or more water jets, resulting in multiple water jetting steps. The required water pressure at each step depends on several parameters, including the number of water jetting steps and the linear velocity. Generally, the more water jetting steps used in this method, the lower the pressure required at each step to achieve the desired fabric properties. In other words, the energy flux obtained using multiple water jets (each applying a certain amount of water pressure) can also be obtained by increasing the number of water jets and decreasing the amount of water pressure applied by each jet. The required water pressure at each step also depends at least in part on the linear velocity. Higher linear velocities require higher pressure to maintain a constant flux. In other words, the energy flux obtained using linear velocity and jet pressure can also be obtained by decreasing both linear velocity and jet pressure.

[0107] Unbound by theory, the preferred total water jet pressure applied to the precursor net 7 is considered to be expressible as energy flux. According to an exemplary embodiment, the preferred energy flux applied to the precursor net 7 is 0.1 to 1.5 kWh / kg, preferably 0.2 to 1.0 kWh / kg. The required energy flux can be obtained, for example, by changing the machine speed and / or the water pressure at each water jet. Preferably, the required energy flux is achieved by using one or more water jets at relatively low pressures rather than using fewer water jets at higher pressures. The energy flux is calculated using the following formula:

[0108] Flux = ((J^1.5)*(G^2)*(I)*(L / 1000)*(7 / 100000000000)) / F, where:

[0109]

[0110] J = water pressure, bar

[0111] g = diameter of jet orifice, in micrometers

[0112] I = orifice / meter of jet stream

[0113] L = width of the nonwoven fabric, in meters

[0114] F = Nonwoven mass flow rate (i.e., the production rate of nonwoven webs, calculated based on linear speed, product width, and basis weight), kg / hr

[0115] A preferred exemplary embodiment of the invention involves the use of a relatively large number of water jets. Unbound by theory, this allows for the use of high linear velocities without requiring increased water pressure. Figure 2A and 2B An exemplary embodiment of the invention is shown, which employs one or more rollers for imparting patterns to a nonwoven fabric. The same elements are used with... Figure 1 Use the same reference numbers to mark them.

[0116] Unbound by theory, it is believed that the properties of the precursor nonwoven web have a strong influence on the characteristics of the final fabric. In this respect, the hydraulically patterned fabrics according to exemplary embodiments of the invention are subjectively pleasing in both visual appearance and tactile feel. The method of the invention produces a nonwoven web in which the pattern of the bonding indentations on the precursor is emphasized, and the final nonwoven product may appear to have a 3D pattern even without 3D forming during the hydraulic treatment step. A suitable combination of precursor patterns highlights the 3D effect and provides further advantages, such as improved tactile properties, or greater thickness while maintaining the same basis weight, which in turn provides performance advantages, such as space for controlling liquid management. Meanwhile, thermal bonding, preferably fully bonded, of the precursor provides the fabric with the necessary mechanical properties, such as strength, elongation, or abrasion resistance.

[0117] Exposing the precursor nonwoven web to hydromoldation as discussed herein provides the desired improvements in pattern visual appeal, thickness, and flexibility. Furthermore, the degradation of mechanical properties (e.g., tensile strength, elongation, or abrasion resistance) is limited. Key features of the precursor nonwoven fabric according to exemplary embodiments of the invention are described below.

[0118] Conventional techniques, particularly U.S. Patent No. 7,858,544 and its family of patents, describe the advantages of using elliptical and so-called anisotropic patterns of adhesive indentations (fusion bonding) defined solely by a percentage of the total bonded area. Surprisingly, it has been found that patterns of non-anisotropic adhesive indentations are well-suited to the hydraulic patterning processes disclosed herein and provide the desired visual effects.

[0119] In an exemplary embodiment, the precursor nonwoven web may have a bonded area percentage preferably at least 5%, and more preferably at least 10%. Without being bound by theory, it is considered that a lower bonded area percentage would not provide sufficient stability for the wadding, and that the fabric is unstable during hydroforming.

[0120] In an exemplary embodiment, the precursor nonwoven web may have a maximum bonded area percentage of preferably 30%, preferably 25%. Without being bound by theory, it is considered that a higher bonded area percentage results in too large a fusion bond indentation area and insufficient space for water flow to interact with the fabric filaments without damaging the bond indentation, thus leading to a significant decrease in the mechanical properties of the final fabric compared to the precursor.

[0121] Besides the percentage of bonded area, the size and shape of the bond indentation and the distance between bond indentations are important parameters in the entire hydraulic patterning process.

[0122] Generally, adhesive indentations can be divided into two groups: adhesive indentation areas less than 1 mm². 2"Small adhesive indentations"; and adhesive indentations with an area equal to or greater than 1 mm² 2 The “large bond indentation” is used. The size of the bond indentation is usually provided by the calender manufacturer and can also be measured on the precursor or estimated from the hydraulically patterned fabric. When measuring from the fabric, at least 20 individual bond indentations of each type are measured using the same method used to determine the percentage area of ​​bond, and the arithmetic mean is calculated.

[0123] Small adhesive indentations are typically arranged in regular patterns in rows and columns, or in lines or various other shapes. For the purposes of this disclosure, adjacent small adhesive indentations are considered as individual adhesive indentations when the minimum distance between them is at least 0.3 mm, preferably at least 0.4 mm, and most preferably at least 0.5 mm.

[0124] According to an exemplary embodiment of the present invention, each 1cm 2 The number of small adhesive indentations on the fabric is at least 20 adhesive indentations per square centimeter, preferably at least 30 adhesive indentations per square centimeter, more preferably at least 40 adhesive indentations per square centimeter, more preferably at least 50 adhesive indentations per square centimeter, and even more preferably at least 60 adhesive indentations per square centimeter.

[0125] Large adhesive indentations can also be arranged in regular patterns in rows and columns, and are large enough that their shapes can be clearly seen with the naked eye in the thermally bonded fabric. The adhesive pattern can be formed by repeating a shape, or it can be composed of a combination of one or more large adhesive shapes.

[0126] Large and small adhesive indentations can also be combined, as described in European Patent EP3452652.

[0127] Examples of various patterns formed by small adhesive indentations, large adhesive indentations, and combinations of small and large adhesive indentations are shown in the accompanying drawings and are described below.

[0128] Unbound by theory, it is believed that the presence of small bonding indentations is advantageous in the hydroforming process because these indentations have a small area and are also slightly movable within the fabric, as each indentation contains a small amount of fused filaments. When water is about to impact the small bonding indentations, the indentations may move slightly in any direction and may also tilt in the z-direction, thus avoiding the full energy from the water flow and limiting potential damage. Unbound by theory, it is believed that the presence of small bonding indentations reduces the degradation of the fabric's mechanical properties during the hydroforming process.

[0129] Large adhesive indentations with carefully selected indentation shapes also have the freedom to move / tilt and avoid receiving all the energy from the water flow, and are therefore also suitable for use with exemplary embodiments of the present invention.

[0130] Unbound by theory, it is considered advantageous to have large adhesive indentations in the form of lines, which are straight, shaped, or curved, and whose width is constant or irregular, for use in the hydroforming process according to an exemplary embodiment of the invention, because such adhesive indentations minimize the degradation of the fabric's mechanical properties during the hydroforming process.

[0131] In an exemplary embodiment, the large linear adhesive indentation is in the form of a continuous line with a line width (W) of at most 0.6 mm, preferably at most 0.5 mm, and most preferably at most 0.4 mm. The large linear adhesive indentations are preferably discontinuous. In an exemplary embodiment, the large linear adhesive indentation has a maximum line length (L) of 30 mm, preferably 25 mm, and more preferably 20 mm.

[0132] Figure 3A , Figure 3B , Figure 3C and Figure 3D Various linear bonding patterns preferred for use according to exemplary embodiments of the present invention are shown. Figure 3A The diagram shows a pattern formed by straight lines of constant width, where the lines constituting each individual indentation are discontinuous. Figure 3B The diagram shows a pattern formed by curves of constant width, where the curves constituting each individual indentation are discontinuous with each other. Figure 3C and Figure 3D The diagram shows a pattern formed by curves of irregular widths, where the curves are continuous with each other. Figure 3C A continuous pattern on the precursor mesh is shown, while Figure 3D A continuous pattern is shown on a water-patterned fabric.

[0133] For the purposes of this disclosure, the length L of the adhesive indentation is measured by identifying the shape length line that intersects the perimeter of the adhesive shape at an intersection point, said intersection point being the largest distance that can be identified on the perimeter, i.e., the distance between the two farthest points on the perimeter. Figure 3A and Figure 3B As shown, the bonded shape has a width W, which is measured by identifying corresponding shape width lines parallel to the shape length lines and tangent to the shape perimeter at one or more outermost points, said outermost points being furthest from the shape length lines on either side. It should be understood that for some shapes (e.g., semicircles), one of the shape width lines may coincide with / be collinear with the shape length lines. The width W is the distance between the shape width lines.

[0134] Unbound by theory, it is believed that linear large bond indentations are more successful in avoiding mechanical damage during the hydraulic patterning process when they are oriented substantially along the MD direction. The linear bond indentations can be angled relative to the MD direction, such that the shape tilt angle αT can be expressed as a small angle formed by the intersection of the axis along the machine direction and the shape length line. The shape tilt angle αT should not exceed 50 degrees, more preferably not more than 40 degrees, even more preferably not more than 30 degrees, and most preferably not more than 20 degrees.

[0135] Unbound by theory, it is believed that linear large adhesive indentations are more successful in avoiding mechanical damage during the hydraulic patterning process when the shape of the adhesive indentation includes at least one convex portion along its perimeter. For example, a linear large adhesive indentation may have a convex portion along its perimeter to present a C-shape, a circle, or a J-shape. For example, a linear large adhesive indentation may have two convex portions to present an S-shape, a B-shape, or an 8-shape, etc.

[0136] The distance between bonding indentations, or in other words, the area of ​​unbonded filaments between bonding indentations, provides space to absorb energy from the water flow, resulting in increased fabric thickness and softness compared to the precursor web. During fabric formation, free filaments are laid on a tape to form a wadding, and then the defined areas of the wadding are fused together to form bonding indentations. A single filament typically extends through many bonding indentations; importantly, the filament path is not straight but forms various loops and turns in all three dimensions, although mostly in the MD-CD plane. The water flow energy of the subsequent hydro-patterning process moves the free portions of the filaments and enhances their path in the third dimension (through the fabric thickness). This results in an increase in fabric thickness. Hydro-patterning also smooths or loosens the harder edges of the bonding indentations (created by protrusions on the calendering rollers and oriented along the fabric surface) and improves the tactile properties of the fabric. Thus, hydro-patterned fabrics according to exemplary embodiments of the invention are very comfortable to the touch and pleasant to wear against the skin. Furthermore, the change in the orientation of the free portions of the filaments results in a change in the visual effect of the fabric. For example, this change may highlight a pattern or a portion of a pattern, and may even induce a 3D perception in flat fabrics. To improve this desired effect, certain shapes and sizes of the unbonded filament areas are preferred.

[0137] Unbound by theory, it is argued that as the size of the free filament region unaffected by adhesive indentations increases, the desired effect of the hydromold patterning process increases. In this regard, the size of the free filament region within the adhesive pattern can be measured by defining a maximum imaginary circle C that encompasses the free filament region and has a perimeter passing through a single point on the perimeter of each of at least two adhesive indentations within the pattern, wherein the size of the free filament region is defined as the radius of the imaginary circle. Figure 4A , Figure 5 , Figure 6A , Figure 7A , Figure 7B , Figure 8A , Figure 9 , Figure 10A and Figure 10B A circle C defined within different bonding patterns is shown according to an exemplary embodiment of the present invention.

[0138] In an exemplary embodiment, circle C has a radius of at least 0.5 mm, preferably at least 1 mm, more preferably at least 1.5 mm, and even more preferably at least 2 mm.

[0139] Unbound by theory, it is believed that non-linear bonding indentations offer advantages when bonded to small indentations and / or free filament regions. Such bonding indentations can have non-linear shapes, such as circular, elliptical, rhomboid, square, rectangular, etc., and do not have an identifiable width W or length L as described above. For the purposes of this disclosure, non-linear or linear bonding indentations with a width of at least 0.6 mm are referred to as large coarse-bodied bonding indentations.

[0140] In exemplary embodiments, features of different patterns can be combined to provide a synergistic effect of the advantages offered by the hydraulic patterning process. Table 1 provides features of various patterns that can be used in the methods according to exemplary embodiments of the present invention.

[0141] For example, standard pattern P1 ( Figure 4A and Figure 4B It consists of small adhesive indentations arranged in rows and columns in a regular pattern. This pattern provides a circle C with a radius of less than 0.5 mm and does not contain large adhesive indentations. It can be expected that this standard pattern will exhibit a relatively small decrease in mechanical properties, but will not provide a large increase in thickness.

[0142] In an exemplary embodiment, small bonding indentations can be arranged around the free filament region to provide the desired advantages. For example, the small bonding indentations can be arranged so that they are directly adjacent to each other to form a line, similar to a stone path on a lawn. Figure 5 This pattern is shown in the diagram, denoted by P6. In this case, hydraulic treatment will only result in a small decrease in mechanical properties and a large increase in fabric thickness.

[0143] In an exemplary embodiment, the pattern of the adhesive indentation consists of an adhesive area of ​​less than 1 mm². 2 The small adhesive indentations are formed, and the minimum distance between adjacent adhesive indentations is at least 0.3 mm, preferably at least 0.4 mm, most preferably at least 0.5 mm, wherein the circle C has a radius of at least 1 mm, preferably at least 2 mm, more preferably at least 3 mm, and even more preferably at least 4 mm.

[0144] In an exemplary embodiment, large bonding indentations can be arranged around the free filament region to provide the desired advantages. For example, elliptical-shaped large bonding indentations can be arranged such that the free filament region separates the large bonding indentations from one another. Figure 6A and Figure 6B This pattern is illustrated in the image, denoted by P2. In this case, large bonding indentations will result in a significant decrease in mechanical properties, but the free filament regions will provide an increase in fabric thickness.

[0145] In an exemplary embodiment, the pattern of the adhesive indentation consists of an adhesive area of ​​at least 1 mm². 2 The large adhesive indentation is formed, wherein the circle C has a radius of at least 0.5 mm, preferably at least 1.0 mm, more preferably at least 1.5 mm, and even more preferably at least 2.0 mm.

[0146] In an exemplary embodiment, the pattern of the adhesive indentation consists of an adhesive area of ​​at least 1 mm. 2 The large, coarse adhesive indentation is formed, wherein the circle C has a radius of at least 0.5 mm, preferably at least 2.0 mm, more preferably at least 1.5 mm, and even more preferably at least 2.0 mm.

[0147] In an exemplary embodiment, large linear bonding indentations can be arranged around the free filament region to provide the desired advantages. For example, the large linear bonding indentations can be composed of a series of curves that, for example, intersect each other to form the free filament region. Figure 7A and Figure 7B This pattern is illustrated in the image, denoted by P7. In this case, the large linear bonding indentations will prevent a significant decrease in mechanical properties, and the free filament areas will provide an increase in fabric thickness.

[0148] In an exemplary embodiment, the pattern of the adhesive indentation consists of large adhesive indentations with a maximum line width (W) of 0.6 mm, preferably 0.5 mm, and most preferably 0.4 mm, wherein the circle C has a radius of at least 1 mm, preferably at least 2 mm, more preferably at least 3 mm, and even more preferably at least 4 mm. The perimeter of the linear adhesive indentation preferably includes at least one convex portion.

[0149] In an exemplary embodiment, discontinuous linear large bonding indentations can be arranged around the free filament region to provide the desired advantages. For example, the linear large bonding indentations can be I-shaped or S-shaped, wherein the bonding indentations are arranged in rows and columns. Figure 8A and Figure 8B This pattern is illustrated in the image, denoted by P3. In this case, the large, discontinuous bonding indentations in the linear shape will prevent a significant decrease in mechanical properties, and the free filament regions will provide an increase in fabric thickness.

[0150] In an exemplary embodiment, the pattern of the adhesive indentation consists of large adhesive indentations with a maximum line width (W) of 0.6 mm, preferably 0.5 mm, and most preferably 0.4 mm, and the large linear adhesive indentations have a maximum length (L) of 30 mm, preferably 25 mm, and more preferably 20 mm, wherein the circle C has a radius of at least 0.5 mm, preferably at least 1.0 mm, more preferably at least 1.5 mm, and even more preferably at least 2.0 mm. The perimeter of the linear adhesive indentation preferably includes at least one convex portion.

[0151] In an exemplary embodiment, large and small bonding indentations can be arranged around the free filament region to provide the desired advantages. For example, large, coarse bonding indentations with circular shapes can be placed relatively far apart from each other, with smaller bonding indentations forming connecting lines between some of the large, coarse bonding indentations, thereby forming a free filament region between the large, coarse bonding indentations and the small bonding indentations. Figure 9 This pattern is illustrated in the image, denoted by P9. In this case, the synergistic effect of the combination provides a small decrease in mechanical properties and a significant increase in thickness and visual appeal. For example, the hydraulic patterning process results in visually prominent large bond indentations and visually suppressed small bond indentations, thereby providing an overall soft, fluffy cushioning pad visual effect, as well as good mechanical properties and abrasion rating.

[0152] In an exemplary embodiment, the pattern of the adhesive indentation consists of an adhesive area of ​​at least 1 mm². 2 Large adhesive indentation, adhesive area less than 1mm 2 The small adhesive indentation consists of a circle C having a radius of at least 1 mm, preferably at least 2 mm, more preferably at least 3 mm, and even more preferably at least 4 mm.

[0153] In an exemplary embodiment, discontinuous linear large and small bonding indentations can be arranged around the free filament region. For example, discontinuous linear large bonding indentations can be used to form visual main patterns that are relatively far apart from each other (e.g., a sun-like pattern), with multiple small bonding indentations arranged between the visual main patterns. Figure 10A and Figure 10B This pattern is illustrated in the image, denoted by P8. In this case, the synergistic effect of the combination will result in a small decrease in mechanical properties and a large increase in thickness and visual effect. For example, the hydraulic patterning process results in visual prominence of the main visual pattern and visual suppression of small adhesions, thereby providing an overall soft, fluffy visual effect, as well as good mechanical properties and wear rating.

[0154] In an exemplary embodiment, the pattern of the adhesive indentation consists of large adhesive indentations with a maximum line width (W) of 0.6 mm, preferably 0.5 mm, most preferably 0.4 mm, and a maximum length (L) of 30 mm, preferably 25 mm, more preferably 20 mm, and an adhesive area of ​​less than 1 mm². 2 The linear adhesive indentation consists of small adhesive marks, wherein the circle C has a radius of at least 1 mm, preferably at least 2 mm, more preferably at least 3 mm, and even more preferably at least 4 mm. The perimeter of the linear adhesive indentation preferably includes at least one convex portion.

[0155] It should be understood that the present invention is not limited to the patterns described herein, and exemplary embodiments may include various other combinations of patterns to achieve the desired advantages of the hydraulic patterning process.

[0156] Without being bound by theory, Equation 1 can be considered as being able to predict suitable thermal bonding patterns for hydraulic patterning processes.

[0157]

[0158] in

[0159]

[0160] K = [(per 1cm) 2 [(Number of adhesive indentations) * 100] / [(Percentage of adhesive area (%) * (Area of ​​the smallest adhesive indentation in the pattern (mm²))] 2 The area of ​​the largest possible circle C (mm²) 2 ))).

[0161] Equation 1 does not apply to patterns containing large adhesive indentations with continuous linear shapes.

[0162] Unbound by theory, a K value greater than 5 is considered ideal for hydroforming processes. When the K value exceeds 20, the fabric should exhibit an increase in thickness during the hydroforming process, and when the K value exceeds 50, the hydroformed fabric should show excellent improvement in visual performance without a significant decrease in mechanical properties. It should be noted that K values ​​above a certain threshold (e.g., 100) can be of equal or similar quality, such that a K value of, for example, 200 is not necessarily better than a K value of 150.

[0163] In an exemplary embodiment, the value of K is at least 5, preferably at least 10, more preferably at least 15, even more preferably at least 25, and most preferably at least 50.

[0164] exist Figure 11 Table 1 provides the characteristics of the bonding patterns that can be used in a hydraulic patterning process according to an exemplary embodiment of the present invention.

[0165] According to an exemplary embodiment of the present invention, the hydropatically patterned fabric prepared by the method described herein is soft, has good tactile properties, and is pleasant to wear on the skin.

[0166] According to an exemplary embodiment, the tensile strength in the CD direction decreases by less than 50%, preferably less than 40%, even more preferably less than 30%, and most preferably less than 20%.

[0167] According to an exemplary embodiment, the tensile strength in the MD direction decreases by less than 50%, preferably less than 40%, even more preferably less than 30%, and most preferably less than 20%.

[0168] According to an exemplary embodiment, the hydraulically patterned nonwoven web has a basis weight of 10 gsm to 60 gsm, preferably 15 gsm to 45 gsm, and most preferably 20 gsm to 35 gsm.

[0169] According to an exemplary embodiment, the hydraulically patterned nonwoven web has a fabric thickness of at least 10 micrometers / gsm, preferably at least 11 micrometers / gsm, and most preferably at least 12 micrometers / gsm.

[0170] According to an exemplary embodiment, the hydraulically patterned nonwoven web has a tensile strength of at least 4 N / cm.

[0171] According to an exemplary embodiment, the hydraulically patterned nonwoven web has a CD tensile strength of at least 2 N / cm.

[0172] According to an exemplary embodiment, the hydraulically patterned nonwoven web provides a high level of softness. Softness itself is a very general term encompassing many various sensations, some of which can be expressed by measurement, such as the Handle-O-Meter test, cantilever test, compressibility, thickness, coefficient of friction, and / or many other methods. It should be noted that each test provides only limited information about softness and may only apply to certain applications or a range of basis weights, polymer compositions, etc.

[0173] Nonwoven webs can be bonded to nonwoven laminates. The nonwoven laminates may contain additional continuous fiber layers, such as spunbond and meltblown fibers, and may contain composite nonwovens, such as spunbond-meltblown-spunbond laminates. Nonwoven laminates may also contain short fibers, such as staple fibers, or may contain pulp fibers. These short fibers may be in the form of a consolidated web, such as a carded web or sheet of paper, or may initially be unconsolidated. Nonwoven laminates may also contain superabsorbent materials, which may be in granular or fibrous form. The laminates can be formed by conventional means, including but not limited to thermal bonding, ultrasonic bonding, chemical bonding, adhesive bonding, and / or hydroentangling. According to exemplary embodiments of the invention, the web can be formed into a nonwoven laminate obtained by one or more of the above methods, used as a top sheet, absorbent core, or bottom sheet of an absorbent article.

[0174] In other exemplary embodiments of the invention, the screen or roller sleeve may not be flat, but may include a 3D shape imparted to the fabric. In exemplary embodiments using a series of rollers, the 3D screen may be used only on the last roller in the production line to provide the complete forming of the precursor fabric. At this point, the rollers preceding the last roller in the production line are preferably not equipped with 3D screens, but may be equipped with mesh screens. In exemplary embodiments, rollers up to the second to the last roller in a row can be used to prepare the precursor fabric for 3D forming, but the actual forming of the precursor fabric preferably takes place at the last roller. It should be understood that in other exemplary embodiments of the invention, the 3D screen may be provided on a belt rather than on a roller.

[0175] In an exemplary embodiment, the multiple steps of water jetting include exposing the thermally bonded nonwoven precursor web 7 to several water jets (each water jet having a set of jets / nozzles), wherein each water jet applies a higher pressure in the machine direction compared to the water jet immediately preceding it. For example, water jet 16c may apply a higher pressure compared to water jet 16b, and water jet 16b may apply a higher pressure compared to water jet 16a. In a particular exemplary embodiment, the amount of pressure applied by water jet 16b is at least 80%, preferably 80% to 95%, of the pressure applied by water jet 16c, and the amount of pressure applied by water jet 16a is at least 80%, preferably 80% to 95%, of the pressure applied by water jet 16b. In an embodiment, water jet 16a applies pressure at at least 64%, preferably 64% to 90%, of the pressure applied by water jet 16c, thereby providing the desired improvements in pattern visual effect, thickness, and softness. Furthermore, the decrease in mechanical properties (e.g., tensile strength, elongation, or abrasion resistance) is limited. The relatively low pressure applied by water jetter 16a results in initial softening of the precursor web, while the higher pressures applied by water jetters 16b and 16c provide improvements in thickness and desired visual appearance. Without being bound by theory, it is thought that the increasing gradient of applied pressure helps maintain individual bond indentations during the softening and thickening stages, thereby minimizing the reduction in mechanical properties such as tensile strength, elongation, or abrasion resistance.

[0176] In the implementation, the water jetting process includes exposing the thermally bonded nonwoven precursor web 7 to two water jetters (each with a set of jets / nozzles), wherein each water jetter applies a higher pressure in the machine direction compared to the water jetter immediately preceding it. For example, water jetter 16c may apply a higher pressure than water jetter 16b, and water jetter 16a may be excluded.

[0177] In the implementation, the water jetting process includes exposing the thermally bonded nonwoven precursor web 7 to four or more water jetters (each water jetter having a set of jetters / nozzles), wherein each water jetter applies a higher pressure in the machine direction compared to the water jetter immediately preceding it.

[0178] In an exemplary embodiment, the hydraulic treatment causes at least a partial change to each adhesive indentation by applying water pressure. At this point, applying water pressure can cause the removal of at least some of the fully bonded portions of each adhesive indentation, such that after the hydraulic application step, at least 60%, preferably at least 70%, more preferably 80%, and even more preferably 90% of the fully bonded portions of each adhesive indentation are retained.

[0179] In one embodiment, applying water pressure can cause individual adhesive indentations to separate into at least two parts. In another embodiment, applying water pressure can cause the overall size of each adhesive indentation to decrease while maintaining the overall profile of each adhesive indentation. For example, as... Figure 16A and Figure 16B As shown, this change can lead to a reduction in the size of the adhesive indentation while maintaining the overall profile of the adhesive indentation. Unbound by theory, it is assumed that at least partial changes to each adhesive indentation result in improved tactile softness without significantly reducing the tensile strength and / or abrasion resistance of the final product. Tactile softness is a complex value that is difficult to express through simple measurements because it represents the sensation provided by a human finger. The values ​​measured in this application (thickness, HOM, COF) are partial measurements of tactile softness, and their values ​​do not represent tactile softness within their complexity.

[0180] In the implementation plan, such as Figures 15A to 15F As shown, applying water pressure causes fibers in the area surrounding the perimeter of each bonding indentation to randomly grind into and out of the main plane of the fully bonded precursor nonwoven web, in order to at least partially remove the natural reinforcing fibers around the perimeter of the bonding indentations, thereby at least partially eliminating the three-dimensionality of each bonding indentation. More specifically, Figure 15A It is a cross-sectional view showing a single bonding indentation formed by a patterned calendering roll 12 and a smooth calender 10, wherein natural reinforcing fibers are present at the edges of the bonding indentation. Figure 15B It is a cross-sectional view of a bonded precursor mesh having a single bond indentation 100 and natural reinforcing fibers at the edge of the bond indentation, and Figure 15C It is a cross-sectional view of a nonwoven web with a single, altered bonding indentation, showing a hydraulically treated surface, where there are no natural reinforcing fibers at the edges of the bonding indentation and the bonding indentation itself is slightly smaller. Figure 15D These are micrographs of a modified cross-section of a single bond indentation according to an exemplary embodiment of the invention, showing how hydraulic treatment results in worn edges around the bond indentation, where no naturally reinforcing fibers are present around the perimeter of the bond indentation. Instead, Figure 15E and Figure 15F It is a micrograph of a cross-section of a conventional precursor bond indentation as shown in U.S. Patent No. 8,410,007, in which the naturally reinforcing fibers are clearly visible.

[0181] Unbound by theory, it is believed that the randomization of fibers around the perimeter of each bonding indentation leads to a softer final product (tactile softness).

[0182] The following examples and comparative examples illustrate the advantages of the present invention.

[0183] Comparative Example 1 (Precursor web of Example 1)

[0184] 25 gsm melt-spun nonwoven wadding is produced online using a continuous process from a mixture of polypropylene (Exxon's 3155E5 type) and copolymer (Exxon's Vistamaxx 6202) in a weight ratio of 80:10, along with an erucamide-based softening and reinforcing additive (Avient's CESA-slipPP 42161). This process produces single-component polypropylene filaments with fiber diameters of 13-25 μm, which are then collected on a moving belt. The REICOFIL 3.1 technology is employed. Reicofil GmbH & Co. KG, Troisdorf, Germany, produces spunbonded mats using four spunbonded die heads. The nonwoven mats are fully bonded by a pair of heated rollers, one of which has a raised pattern P2 ( Figure 6A , Figure 6B The temperature of the calendering rolls (smoothing rolls / embossing rolls) was 160℃ / 156℃, and the bonding pressure was 110N / mm. The resulting nonwoven web was considered not to be fully bonded and had the material properties shown in Tables 2 and 3.

[0185] Example 1

[0186] The same nonwoven web was formed as described in Comparative Example 1, but with an additional hydraulic patterning step. Hydraulic patterning was achieved using two rollers with identical settings (a metal mesh screen and two jets at the rollers, each applying a water pressure of 125 bar). Each jet had two rows of holes spaced 0.6 mm apart (type 2j12). The fabric was moved at a speed of 300 m / min. The resulting nonwoven web exhibited the material properties shown in Tables 2 and 3.

[0187] Comparative Example 2 (Precursor Web of Example 2)

[0188] 25 gsm melt-spun nonwoven wadding is produced online using a continuous process from a mixture of polypropylene (Exxon's 3155E5 type) and copolymer (Exxon's Vistamaxx 6202) in a weight ratio of 80:10, along with an erucamide-based softening and reinforcing additive (Avient's CESA-slipPP 42161). This process produces single-component polypropylene filaments with fiber diameters of 13-25 μm, which are then collected on a moving belt. The REICOFIL 3.1 technology is employed. Reicofil GmbH & Co. KG, Troisdorf, Germany) produces wadding using four spunbond dies. The nonwoven wadding is fully bonded by a pair of heated rollers, one of which has a raised pattern P2 ( Figure 6A , Figure 6BThe temperature of the calendering rolls (smoothing rolls / embossing rolls) was 163℃ / 161℃, and the bonding pressure was 130 N / mm. The resulting nonwoven web was considered to be fully bonded and had the material properties shown in Tables 2 and 3.

[0189] Example 2

[0190] The same nonwoven web was formed as described in Comparative Example 2, but with an additional hydraulic patterning step. Hydraulic patterning was achieved using two rollers with identical settings (a metal mesh screen and two jets at the rollers, each applying a water pressure of 125 bar). Each jet had two rows of holes spaced 0.6 mm apart (type 2j12). The fabric was moved at a speed of 300 m / min. The resulting nonwoven web exhibited the material properties shown in Tables 2 and 3.

[0191] Comparative Example 3 (Precursor web of Example 3)

[0192] 25 gsm melt-spun nonwoven wadding is produced online using a continuous process from a mixture of polypropylene (Exxon's 3155E5 type) and copolymer (Exxon's Vistamaxx 6202) in a weight ratio of 75:15, along with an erucamide-based softening and reinforcing additive (Avient's CESA-slipPP 42161). This process produces single-component polypropylene filaments with fiber diameters of 13-25 μm, which are then collected on a moving belt. The REICOFIL 3.1 technology is employed. Reicofil GmbH & Co. KG, Troisdorf, Germany, produces nonwoven mats using a single spunbonding die. The nonwoven mats are fully bonded by a pair of heated rollers, one of which has a raised pattern P3. Figure 8A , Figure 8B The temperature of the calendering roll (smoothing roll / embossing roll) was 160℃ / 163℃, and the bonding pressure was 130N / mm. The resulting nonwoven web was considered to be fully bonded and had the material properties shown in Tables 2 and 3.

[0193] Example 3

[0194] The same nonwoven web was formed as described in Comparative Example 3, but with an additional hydraulic patterning step. Hydraulic patterning was achieved using two rollers with identical settings (a metal mesh screen and two jets at the rollers, each applying a water pressure of 125 bar). Each jet had two rows of holes spaced 0.6 mm apart (type 2j12). The fabric was moved at a speed of 300 m / min. The resulting nonwoven web exhibited the material properties shown in Tables 2 and 3.

[0195] Comparative Example 4 (Precursor web of Example 4)

[0196] In a continuous process, 25 gsm melt-spun nonwoven wadding is produced online from a mixture of polypropylene (Exxon's 3155E5 type), a low molecular weight additive (Idemitsu's L-MODU), and an erucamide-based softening and reinforcing additive (Avient's CESA-Slippery PP 42161). This process produces single-component polypropylene filaments with a fiber diameter of 13-25 μm, which are then collected on a moving belt. The REICOFIL 3.1 technology is employed. Reicofil GmbH & Co. KG, Troisdorf, Germany, produces spunbonded mats using four spunbonded die heads. The nonwoven mats are fully bonded via a pair of heated rollers, one of which has a raised pattern P7 (…). Figure 7A , Figure 7B The temperature of the calendering roll (smoothing roll / embossing roll) was 160℃ / 165℃, and the bonding pressure was 110N / mm. The resulting nonwoven web was considered to be fully bonded and had the material properties shown in Tables 2 and 3.

[0197] Example 4

[0198] The same nonwoven web was formed as described in Comparative Example 4, but with an additional hydraulic patterning step. Hydraulic patterning was achieved using two rollers with identical settings (a metal mesh screen and two jets at the rollers, each applying a water pressure of 125 bar). Each jet had two rows of holes spaced 0.6 mm apart (type 2j12). The fabric was moved at a speed of 300 m / min. The resulting nonwoven web exhibited the material properties shown in Tables 2 and 3.

[0199] Comparative Example 5 (Precursor web of Example 5)

[0200] 25 gsm melt-spun nonwoven wadding is produced online using a continuous process from a mixture of polypropylene (Mosten NB425 from Unipetrol) and copolymer (Vistamaxx 6202 from Exxon) at a weight ratio of 95:5, a color additive (SCC 91056 from Standridge Color Corporation), and an erucamide-based softening reinforcement additive (CESA-slipPP 42161 from Avient). The process produces single-component polypropylene filaments with a fiber diameter of 13-25 μm, which are then collected on a moving belt. The wadding is produced using REICOFIL 3.1 technology with four spunbonding dies. The nonwoven wadding is fully bonded by a pair of heated rollers, one of which has a raised pattern P5 (…). Figure 9The temperature of the calendering roll (smoothing roll / embossing roll) was 162℃ / 162℃, and the bonding pressure was 105 N / mm. The resulting nonwoven web was considered to be fully bonded and had the material properties shown in Tables 2 and 3.

[0201] Example 5

[0202] The same nonwoven web was formed as described in Comparative Example 5, but with an additional hydraulic patterning step. Hydraulic patterning was achieved using two rollers with identical settings (a metal mesh screen and two jets at the rollers, each applying a water pressure of 125 bar). Each jet had two rows of holes spaced 0.6 mm apart (type 2j12). The fabric was moved at a speed of 300 m / min. The resulting nonwoven web exhibited the material properties shown in Tables 2 and 3.

[0203] Comparative Example 6 (Precursor web of Example 6)

[0204] 35 gsm melt-spun nonwoven wadding is produced online using a continuous process from a mixture of polypropylene (Exxon's 3155E5 type) and a coloring additive (StandridgeColor Corporation's SCC 91056). This process produces single-component polypropylene filaments with a fiber diameter of 13-25 μm, which are then collected on a moving belt. The wadding is produced using REICOFIL 5 technology with three spunbonding dies. The nonwoven wadding is fully bonded by a pair of heated rollers, one of which has a raised P6 pattern. Figure 5 The temperature of the calendering roll (smoothing roll / embossing roll) was 160℃ / 162℃, and the bonding pressure was 75N / mm. The resulting nonwoven web has the material properties shown in Tables 2 and 3.

[0205] Example 6

[0206] The same nonwoven web was formed as described in Comparative Example 6, but with an additional hydraulic patterning step. Hydraulic patterning was achieved using two rollers. The first roller had a metal mesh screen and an ejector at which 80 bar of water pressure was applied. The ejector at the first roller had two rows of holes, with the holes in each strip spaced 1.2 mm apart. The second roller had an MPC screen and three ejectors at which water pressures of 90 bar, 90 bar, and 150 bar were applied, respectively. Each of the three ejectors at the second roller had two perforated strips, with the holes in each strip spaced 0.6 mm apart. The fabric was moved at a speed of 100 m / min. The resulting nonwoven web exhibited the material properties shown in Tables 2 and 3.

[0207] Comparative Example 7 (Precursor web of Example 7)

[0208] 30 gsm melt-spun nonwoven mats were produced online using a continuous process from core / sheath bicomponent filaments with a ratio of 80:20. The core was formed from an aliphatic polyester (PLA Ingeo 6100D from Nature Works), and the sheath was formed from an aliphatic polyester (PLA Ingeo 6752s from Nature Works) with a lower melting point and crystallinity, combined with a lubricating additive (Avient CR Bio 2144 from Avient). Bicomponent filaments with a fiber diameter of 15–30 μm were produced and subsequently collected on a moving belt. The mats were produced using REICOFIL 4 technology from a single spunbonding die. The nonwoven mats were fully bonded by a pair of heated rollers, one of which had a raised pattern P1 (…). Figure 4A The temperature of the calendering rolls (smoothing rolls / embossing rolls) was 140℃ / 138℃, and the bonding pressure was 50N / mm. The resulting nonwoven web has the material properties shown in Table 4.

[0209] Example 7

[0210] The same nonwoven web was formed as described in Comparative Example 7, but with the additional step of hydraulic patterning. Hydraulic patterning was achieved using two rollers. The first roller had a metal mesh screen and an ejector at which 80 bar of water pressure was applied. The ejector at the first roller had two rows of holes, with the holes in each strip spaced 1.2 mm apart. The second roller had an MPC screen and three ejectors at which water pressures of 90 bar, 90 bar, and 150 bar were applied, respectively. Each of the three ejectors at the second roller had two perforated strips, with the holes in each strip spaced 0.6 mm apart. The fabric was moved at a speed of 100 m / min. The resulting nonwoven web exhibited the material properties shown in Tables 2 and 3.

[0211]

[0212]

[0213] Table 2

[0214]

[0215] Table 3

[0216] As can be seen from Table 2, each nonwoven web described in Examples 1 through 6 showed an improvement in thickness compared to its corresponding comparative example, while also providing a certain level of reduction in mechanical properties. The results varied depending on the thermal bonding pattern on the precursor. Examples 1 and 2, under the same pattern and processing conditions, presented differences between a less bonded (incompletely bonded) precursor and a fully bonded precursor. Both examples provided positive effects on thickness (22% and 17%, respectively), with the less bonded material providing a higher increase (22%) compared to the fully bonded material. The differences were small but still noteworthy. It should be noted that the difference in the reduction in mechanical properties was significant, with the fully bonded material (approximately -22% on MD and -35% on CD) showing a significantly lower reduction in tensile strength in both the CD and MD directions compared to the less bonded material (approximately -35% on MD and approximately -54% on CD). Since an appropriate level of bonding is a crucial factor in the tensile strength of the fabric, the fully bonded precursor provided higher tensile strength compared to the less bonded precursor, resulting in even greater differences in tensile strength after hydroforming.

[0217] The examples illustrate the effects of various thermal bonding pattern types on the final fabric properties. Examples 1 and 2 involve the use of patterns with large, coarse bonding indentations and varying free filament regions between the indentations. As expected, this combination provides a moderate increase in thickness and a relatively large decrease in mechanical properties. Based on the present disclosure, it can be anticipated that when large, coarse bonding indentations are present in the pattern without varying free filament regions, such as in pattern P1, the decrease in mechanical properties will be at least the same as observed in Examples 1 and 2, and the increase in thickness will not be as significant. Conversely, when large bonding indentations are arranged to form larger free filament regions, a greater increase in thickness can be expected.

[0218] Example 3 illustrates the desired mechanical properties of the precursor provided by discontinuous adhesive indentations in a linear pattern arranged in columns and rows. This design with mutually displaced strait rows provides a free filament region with a circular C-shape of 0.99 mm. As expected, Example 3 results in minimal mechanical degradation (values ​​+1% and -3%) and a significant increase in thickness (+14%). It should be noted that this increase cannot be compared with Examples 1 and 2 because the polymer compositions are different. The higher amount of copolymer used in the polymer composition of Example 3 results in a softer fabric with more flexible filaments (see HOM values), which does not provide the same level of thickness provided by the slightly stiffer polymer compositions used in Examples 1 and 2.

[0219] Example 4 involves using a continuous linear bond indentation with a convex portion and a large free filament region having a circle C with a radius of 2.18 mm. As expected, Example 4 results in minimal mechanical degradation (-4%; +5%) and a significant increase in thickness (+11%). It is anticipated that using a small bond indentation with the same shape as the small bond indentation in Example 4 would provide an even greater increase in thickness, since the filaments would not be fixed in a closed, continuous bond shape. It should also be anticipated that forming a large, discontinuous linear bond indentation similar to the design of P7 would provide an increase in thickness and mechanical properties somewhere between the shape provided by the P7 pattern and the same shape formed by small bond indentations.

[0220] Pattern P7 provides a high level of tensile strength (see MDT values ​​compared to other embodiments) while also providing a subjective feeling of softness upon contact with human skin. This subjective value cannot be easily expressed by a single measurement and was assessed by a group of trained individuals. A significant increase in this subjective softness was observed. The precursor fabric and the treated product were examined under an electron microscope, and [the following text is incomplete and likely refers to further details about the fabric and product]. Figure 12A and Figure 12B Differences were observed. Even though the adhesive indentations appeared unclear in the hydraulically patterned photographs, it is not bound by theory that the energy flux could not provide sufficient energy to significantly disrupt the linear adhesive indentations and could possibly partially alter the adhesive indentation surface to provide a softer, more human feel. It should be noted that an increased subjective perception of a softer tactile feel was observed in all hydraulically patterned samples.

[0221] Example 5 involves the use of small adhesive indentations (0.9 mm). 2 Large adhesive indentation (23.7mm) 2 Pattern P5 is formed by the combination of a large C-radius area and a free filament region (circle C radius 2.54 mm). As expected, a significant increase in thickness (+54%) was observed in Example 5. Without being bound by theory, it is believed that the substantial increase in thickness is due to the combination of the large C-radius and the small bonding indentations forming around the boundary line of the free filament region. The decrease in mechanical properties due to the presence of large bonding indentations is acceptable (-36%; -29%). It should be noted that the final fabric exhibits a visually 3D-like "buffering" effect produced by the large bonding points in the P5 pattern.

[0222] While a detailed description of specific embodiments of the invention has been set forth in the foregoing specification, it should be understood that those skilled in the art may make significant changes to many of the details set forth herein without departing from the spirit and scope of the invention.

[0223] The tensile strength and elongation of nonwoven fabrics are measured using the test method according to WSP 110.4.R4(12) standard. Tensile strength can also be expressed as “MDT” in the MD direction and “CDT” in the CD direction. Therefore, elongation can also be expressed as “MDE” in the MD direction and “CDE” in the CD direction.

[0224] The "Handle-O-Meter" or "HOM" stiffness test for nonwoven materials is performed according to WSP Test Method 90.3, with slight modifications. The quality of the "hand" is considered to be a combination of resistance caused by surface friction and the sheet's bending stiffness. The equipment used for this test method is available from Thwing Albert Instrument Co. In this test method, a 100×100 mm sample is used for HOM measurement, and the final reading is reported "as is" in grams, rather than doubling the reading according to WSP Test Method 90.3. The average HOM is obtained by averaging the MD and CD HOM values. Generally, a lower HOM value indicates higher softness and flexibility, while a higher HOM value indicates lower softness and flexibility in the nonwoven fabric.

[0225] The “thickness”, “measurement height”, or “caliper” of nonwoven materials is determined by the test measurement method according to European standard EN ISO 9073-2:1995 (corresponding to method WSP 120.6), modified as follows:

[0226] 1. The material is measured by using a sample taken from the manufacturing process, which is not subjected to high deformation forces or pressure for more than one day (e.g., by pressure applied to the manufacturing equipment by rollers), but the material must be left to rest freely on a surface for at least 24 hours.

[0227] 2. The total pressure used for thickness measurement is 14.7 g / cm. 2 .

[0228] The "dynamic coefficient of friction" or "dynamic CoF" of nonwoven materials was determined according to ASTM D 1894 using a 32-07 series friction tester from TestingMachines Inc. The reported data represent the coefficient of dynamic friction (CoF) between nonwovens placed on a 10cm × 10cm nonwoven fabric under a 200g slide plate, which was pulled across a 25cm × 10cm clamped sample of the same nonwoven fabric, maintaining lateral movement and orientation consistency (A-side to A-side; MD-direction to MD-direction) at a speed of 150mm / min.

[0229] Wear rating: "Martindale Average Abrasion Rating Test" or "Martindale"

[0230] Figure 13 This is a perspective view of the equipment used for testing the Martindale average abrasion resistance rating. Specifically, Figure 13 This illustrates the grading scale used for napping assessment in the Martindale Average Abrasion Rating Test.

[0231] The average abrasion resistance of nonwoven fabrics was measured using a Martindale abrasion tester. The fabric was dried before testing.

[0232] 1. Condition the nonwoven sample at 23±2℃ and 50±2% relative humidity for 24 hours.

[0233] 2. Cut 10 circular samples with a diameter of 162 mm (6.375 inches) from each nonwoven sample. Cut a standard felt into circles with a diameter of 140 mm.

[0234] 3. Each sample is secured to its position on each Martindale test grinding table by first placing the cutting felt, then placing the cut nonwoven sample. The clamping rings are then secured, so no wrinkles are visible on the nonwoven sample.

[0235] 4. Assemble the abrasive holder. The abrasive is 38mm diameter, FDA-compliant, 1 / 32-inch thick silicone rubber (from McMaster Carr, Project 86045K21-50A). Place the required weight in the abrasive holder to apply 9 kPa pressure to the sample. Place the assembled abrasive holder in the #864 housing, ensuring the abrasive contacts the NW sample as indicated in the operator's guide.

[0236] 5. Operate Martindale wear under the following conditions:

[0237] 1. Mode: Wear Test

[0238] 2. Speed: 47.5 cycles / minute; and

[0239] 3. Loops: 80 loops without different explanations.

[0240] 6. After the test is stopped, place the abraded nonwoven fabric on a smooth, matte, black surface and use... Figure 14 The scale provided in the rating scale is used to grade the napping level. Each sample is evaluated by observing from the top to determine the size and number of defects, and by observing from the side to determine the napping height of the defects. A number from 5 to 1 is assigned based on the best match with the rating scale. The Martindale average abrasion rating is then calculated as the average rating of all samples and reported to the nearest tenth.

[0241] "Percentage of bonded area" is calculated using ImageJ software (Vs.1.43u, National Institutes of Health, USA) by identifying a single repeating pattern in bond indentations and unbonded areas and magnifying the image so that the repeating pattern fills the field of view. A bounding box containing the repeating pattern is drawn in ImageJ. The area of ​​the box is calculated and recorded to the nearest 0.01 mm. 2 Next, using the area tool, trace individual adhesive indentations or the portion of each indentation entirely within the frame, and calculate the area of ​​all adhesive indentations or the portion of each indentation entirely within the frame. Record to a value as close as 0.01 mm. 2 Calculate as follows:

[0242] Percentage of bonded area = (Sum of the areas of bonded indentations within the frame) / (Frame area) × 100%

[0243] Repeat the measurements for a total of five non-adjacent ROIs randomly selected throughout the entire sample. Record the percentage of bonded area as the closest to 0.01%. Measure two samples from each article. Measure a total of three identical articles for each sample group. Calculate the mean and standard deviation of the percentages of all 30 bonded area measurements and report them as the closest to 0.001 units.

Claims

1. A method for forming a hydraulically patterned nonwoven web, including: Forming a nonwoven wadding consisting of continuously melt-spun fibers; The nonwoven pad is calendered and bonded to form a thermally bonded precursor nonwoven web with a bonding pattern that defines bonding indentations and unbonded areas between bonding indentations. as well as When the thermally bonded nonwoven web passes through a screen, the thermally bonded precursor nonwoven fabric undergoes hydraulic treatment through multiple water jet steps, wherein... The adhesive pattern has an adhesive area percentage of 10% to 25%. An imaginary circle C is defined as the largest circle that can be drawn between the unbonded areas and has a perimeter that intersects a single point on the perimeter of each of at least two adjacent adhesive indentations within the adhesive pattern, and the circle C has a radius of at least 0.5 mm in the unbonded areas. The bonding pattern includes an bonding indentation area of ​​at least 1 mm. 2 Large, bold adhesive indentations.

2. The method of claim 1, wherein the step of forming the precursor nonwoven web comprises the melt-spun fibers of the nonwoven wadding composed of spunbond filaments.

3. The method of claim 1, wherein the step of forming the precursor nonwoven web includes the nonwoven wadding comprising two or more layers.

4. The method of claim 3, wherein the melt-spun fibers in each of the two or more layers comprise spunbond filaments.

5. The method of claim 3, wherein the average fiber thickness difference between the two or more layers is less than 20%.

6. The method of claim 3, wherein at least one of the two or more layers comprises spunbond filament, and at least one other layer of the two or more layers comprises meltblown fiber.

7. The method of claim 6, wherein at least one layer of the spunbond filament forms at least one outer layer of the nonwoven wadding.

8. The method of claim 7, wherein the two or more layers comprise at least three layers forming a spunbond-meltblown-spunbond structure.

9. The method of claim 1, further comprising the step of applying at least one layer formed of fibers and / or particles to the fully bonded precursor nonwoven web prior to the hydraulic treatment step.

10. The method of claim 9, wherein the fiber is a short synthetic fiber.

11. The method of claim 9, wherein the fiber is a natural fiber.

12. The method of claim 1, wherein the step of forming the precursor nonwoven web includes the continuous melt-spun fiber, the continuous melt-spun fiber comprising a polyolefin or polyamide or polyester or polysaccharide homopolymer, copolymer or polymer blend.

13. The method of claim 12, wherein the step of forming the precursor nonwoven web comprises the continuous melt-spun fiber, the continuous melt-spun fiber comprising polypropylene, polyethylene, polylactic acid, polyhydroxyalkanoate, polyhydroxybutyrate, polybutylene succinate, polyethylene terephthalate, thermoplastic starch, copolymers thereof, copolymers thereof with olefins, esters, amides or other polymers, or blends thereof.

14. The method of claim 1, wherein the step of forming the precursor nonwoven web comprises the melt-spun fibers containing multiple components.

15. The method of claim 14, wherein the component polymer composition present on at least 40% of the surface of each filament has a lower melt temperature than the melt temperature of at least one other component polymer composition, by a difference of at least 2°C.

16. The method of claim 1, wherein the step of forming the precursor nonwoven web includes the melt-spun fiber, the melt-spun fiber comprising a bicomponent core-sheath continuous melt-spun fiber having a core comprising polypropylene and a sheath comprising a blend of polypropylene and a polypropylene-polyethylene copolymer.

17. The method of claim 1, wherein the continuous melt-spun fiber comprises an additive.

18. The method of claim 17, wherein the additive comprises additives selected from the following types: coloring pigments, softening enhancers, slip agents, fillers, and combinations thereof.

19. The method of claim 1, wherein the step of forming the precursor nonwoven web includes comprising bonding indentation area less than 1 mm². 2 The adhesive pattern with small adhesive indentations.

20. The method of claim 1, wherein the step of forming the precursor nonwoven web includes the circle C having a radius of at least 1 mm.

21. The method of claim 1, wherein the step of forming the precursor nonwoven web includes a minimum distance of at least 0.3 mm between adjacent bonding indentations.

22. The method of claim 1, wherein the step of forming the precursor nonwoven web includes the bonding indentation having the shape of a line of constant width with a maximum line width of 0.6 mm.

23. The method of claim 1, wherein the step of forming the precursor nonwoven web includes the bonding indentation, the bonding indentation having the shape of a line of irregular width with a maximum line width of 0.6 mm.

24. The method of claim 1, wherein the step of forming the precursor nonwoven web includes the adhesive indentation having a line shape, the adhesive indentation having an adhesive shape perimeter including at least one convex portion.

25. The method of claim 1, wherein the step of forming the precursor nonwoven web includes the adhesive indentation having the shape of a continuous line.

26. The method of claim 1, wherein the step of forming the precursor nonwoven web includes the adhesive indentation having the shape of a line with a maximum length of 30 mm.

27. The method of claim 1, wherein the step of forming the precursor nonwoven web includes the bonding pattern, the bonding pattern comprising bonding indentation areas equal to or greater than 1 mm². 2 Large, bold adhesive indentations.

28. The method of claim 1, wherein the hydraulic treatment step comprises applying water pressure to the precursor nonwoven web using a water jet.

29. The method of claim 28, wherein the hydraulic treatment step comprises applying water pressure to the precursor nonwoven web via at least two sets of water jets.

30. The method of claim 29, wherein the method is performed at a linear velocity of at least 150 m / min.

31. The method of claim 30, wherein the linear velocity is 450 m / min or less.

32. The hydraulically patterned nonwoven web produced by the method according to claim 1.

33. The hydraulically patterned nonwoven web of claim 32, wherein the basis weight of the web is 60 gsm or less.

34. The hydraulically patterned nonwoven web of claim 33, wherein the web has a tensile strength of at least 4 N / cm.

35. The hydraulically patterned nonwoven web of claim 34, wherein the web has a CD tensile strength of at least 2 N / cm.

36. The hydro-patterned nonwoven web of claim 35, wherein the web has a thickness of at least 10 micrometers / gsm of fabric.

37. The method of claim 1, wherein the hydraulic treatment step comprises applying water pressure to the precursor nonwoven web by more than one set of water jets, each set of water jets applying a pressure greater than that applied by a set of water jets preceding that set of water jets in the machine direction.

38. The method of claim 37, wherein the three sets of water jets comprise a first set of water jets, a second set of water jets located in the machine direction preceding the first set of water jets, and a third set of water jets located in the machine direction preceding the first set of water jets and the second set of water jets, the second set of water jets applying a pressure of 80% to 95% of the pressure applied by the first set of water jets, and the third set of water jets applying a pressure of 64% to 90% of the pressure applied by the second set of water jets.

39. The method of claim 1, wherein the hydraulic treatment step includes at least partially altering the respective adhesive indentations by applying water pressure.

40. The method of claim 39, wherein the at least partially altered step results in at least 60% of the fully bonded portion of each adhesive indentation being retained after the hydraulic application step.

41. The method of claim 39, wherein the at least partially altered step results in at least 70% of the fully bonded portion of each adhesive indentation being retained after the hydraulic application step.

42. The method of claim 39, wherein the at least partially altered step results in at least 80% of the fully bonded portion of each adhesive indentation being retained after the hydraulic application step.

43. The method of claim 39, wherein the at least partially altered step results in at least 90% of the fully bonded portion of each adhesive indentation being retained after the hydraulic application step.

44. The method of claim 39, wherein the step of at least partially altering the adhesive indentation results in dividing each adhesive indentation into at least two parts.

45. The method of claim 39, wherein the at least partially altered step causes fibers in the region surrounding the perimeter of each adhesive indentation to randomly grind into and out of the main plane of the fully bonded precursor nonwoven web, so as to at least partially eliminate the three-dimensionality of each adhesive indentation.

46. ​​Methods for forming hydraulically patterned nonwoven webs, including: Forming a nonwoven wadding consisting of continuously melt-spun fibers; The nonwoven pad is calendered and bonded to form a thermally bonded precursor nonwoven web with a bonding pattern that defines bonding indentations and unbonded areas between bonding indentations. as well as When the thermally bonded nonwoven web passes through a screen, the thermally bonded precursor nonwoven fabric undergoes hydraulic treatment through multiple water jet steps, wherein... The adhesive pattern has an adhesive area percentage of 10% to 25%. The bonding pattern includes bonding indentations with an area of ​​less than 1 mm. 2 Small adhesive indentations, and The bonding pattern includes an bonding indentation area of ​​at least 1 mm. 2 Large adhesive indentations.

47. A method for forming a hydraulically patterned nonwoven web, including: Forming a nonwoven wadding consisting of continuously melt-spun fibers; The nonwoven pad is calendered and bonded to form a thermally bonded precursor nonwoven web with a bonding pattern that defines bonding indentations and unbonded areas between bonding indentations. as well as When the thermally bonded nonwoven web passes through a screen, the thermally bonded precursor nonwoven fabric undergoes hydraulic treatment through multiple water jet steps, wherein... Regular bonding patterns have a bonding area percentage of 10% to 25%. The bonding pattern includes an bonding indentation area of ​​at least 1 mm. 2 Large adhesive indentations, The adhesive indentation has the shape of a line with an irregular width, with a maximum line width of 0.6 mm. The adhesive indentation has the shape of a line with a length of at least 30 mm and a maximum length of 25 mm.

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