EP4562238A1

EP4562238A1 - Patterned nonwoven substrates made from forming surface with regions of high porosity and low porosity

Info

Publication number: EP4562238A1
Application number: EP23847390.4A
Authority: EP
Inventors: Stephen M. LINDSAY; Adam J. SCHMIDT; Palani Wallajapet Ramaswami RAJ
Original assignee: Kimberly Clark Worldwide Inc; Kimberly Clark Corp
Current assignee: Kimberly Clark Worldwide Inc; Kimberly Clark Corp
Priority date: 2022-07-29
Filing date: 2023-07-28
Publication date: 2025-06-04
Also published as: MX2025000924A; AU2023315854A1; CN119816633A; EP4562238A4; WO2024026090A1; US20260043178A1; KR20250043529A

Abstract

A process and system for producing nonwoven substrates are disclosed. Also disclosed is a forming surface or forming wire for producing the substrates. The forming surface includes a pattern of high porosity zones and low porosity zones. The low porosity zones have a non-zero but low porosity. A wet suspension of fibers is deposited onto the forming surface to form nonwoven substrates having areas of high basis weight and low basis weight. The low porosity zones have a width dimension that is greater than the average fiber length of at least some of the types of fibers contained in the fiber furnish to form substrates having exceptional properties, especially with respect to fluid control properties.

Description

PATTERNED NONWOVEN SUBSTRATES MADE FROM FORMING SURFACE WITH REGIONS OF HIGH POROSITY AND LOW POROSITY

RELATED APPLICATIONS

The present application is based upon and claims priority to U.S. Provisional Patent Application Serial No. 63/396,677, having a filing date of August 10, 2022, and U.S. Provisional Patent Application Serial No. 63/393,305, having a filing date of July 29, 2022, both of which are incorporated herein by reference.

BACKGROUND

Many different types of nonwoven materials exist that are designed to have different functions. In many embodiments, the nonwoven materials are designed to have liquid handling properties. These nonwoven materials can be used in absorbent articles or used to produce wiping products, tissue products, and the like.

Absorbent articles, also referred to as personal care products, such as diapers, diaper pants, training pants, adult incontinence products, and feminine care products, can include a variety of substrates. For example, a diaper can include an absorbent structure, nonwoven materials, and films. Similarly, facial tissues, wipes, and wipers can also include various substrates. Some of the substrates in these products can include natural and/or synthetic fibers. In some products, some substrates can also include different types of components to provide additional functionality to the substrate and/or the end product itself.

For example, one such component that may be desirable to add to a substrate includes a superabsorbent material (SAM). SAM can be configured in the form of a particle or a fiber and is commonly utilized in substrates for increased absorbent capacity. Absorbent systems of personal care absorbent products, such as a diaper, often include SAM.

In many applications, liquid absorbent nonwoven materials should not only have good liquid absorbent properties, but should also have good fluid handling properties. In addition to having good fluid handling properties, the nonwoven materials should also be flexible and made from as little material as possible. The present disclosure is directed to further improvements in the formation of nonwoven materials so as to optimize fluid handling, improve fluid absorbency characteristics, and/or improve at least one other physical property of the materials. The present disclosure is also directed to further improvements in systems and processes for producing the nonwoven substrates.

SUMMARY

In general, the present disclosure is directed to a process and system for producing nonwoven webs. The nonwoven webs are formed with regions of high and low basis weight and/or thickness through the use of a unique and improved forming surface. Through the process of the present disclosure, nonwoven webs can be produced having elongated fluid control canals that can be used in fluid absorbent products to quickly intake and distribute fluids. The fluid control canals also function as points of greater flexibility, especially when making substrates having a relatively high overall basis weight. In one aspect, the low basis weight areas can also be used for slitting the nonwoven webs in a more efficient way that may enable faster converting speeds and reduce wear on slitting equipment. As will be described in greater detail below, the process of the present disclosure, forming wires made according to the present disclosure, and nonwoven products made according to the present disclosure offer many different advantages and benefits.

In one embodiment, the present disclosure is directed to a process for forming nonwoven substrates. The process includes depositing a wet suspension of fibers onto a forming surface. The suspension of fibers includes at least a first type of fiber having an average fiber length. The forming surface includes a pattern of porous first zones and porous second zones. The first zones have a porosity greater than a porosity of the second zones. For example, the porosity of the second zones can be at least about 50% less, such as at least about 60% less, such as at least about 70% less, such as at least about 80% less, such as at least about 90% less than the porosity of the first zones. In accordance with the present disclosure, the second zones have a width dimension that is greater in distance than the average fiber length of the first type of fibers. In one aspect, for instance, the width dimension of the second zones is greater than all of the fibers contained in the wet suspension.

Fluids are drained from the forming surface causing a continuous nonwoven substrate to form having high basis weight areas corresponding to the first zones and low basis weight areas corresponding to the second zones.

The porosity of the second zones is non-zero and can be substantially less than the porosity of the first zones. In one aspect, the second zones can have a porosity such that the second zones have less than about 20%, such as less than about 10%, such as less than about 7%, such as less than about 5%, such as less than about 3% open area and generally greater than about 1%, such as greater than about 2% open area.

In one embodiment, the suspension of fibers can contain a plurality of different types of fibers. For instance, the suspension of fibers can include the first fiber type, a second fiber type, a third fiber type, a fourth fiber type, and so on. Each different fiber type can have a different average fiber length and the width dimension of the second zones can be greater than the longest of the average fiber lengths. In addition to fibers, the suspension can also contain other solid matter, including superabsorbent particles. The width dimension of the second zones (the widest part of the second zones) can be greater than about 2 mm, such as greater than about 4 mm, such as greater than about 5 mm, such as greater than about 6 mm, such as greater than about 7 mm, and generally less than about 15 mm, such as less than about 10 mm, such as less than about 9 mm. The second zones can be present on the forming surface in any suitable pattern. In one embodiment, the second zones form elongated columns on the forming surface that can extend in the machine direction, in the cross-machine direction, or can extend diagonal to the machine direction. In one embodiment, the columns can be linear and can be parallel. Optionally, the columns can have a curvature or a plurality of curvatures.

In one embodiment, the low porosity second zones do not substantially affect the topography of the forming surface. For instance, the forming surface can be substantially planar, meaning that the first and second zones do not differ in height by more than 0.5 mm, such as by no more than about 0.1 mm. In one embodiment, the forming surface comprises a fabric formed from woven yarns. The second zones can be created by applying an additive material to the fabric. The additive material, for instance, can be any suitable polymer material, such as a thermoplastic polymer. In one aspect, the additive material can be applied to the fabric using a three-dimensional printing device.

As described above, nonwoven substrates made according to the present disclosure can include low basis weight areas and high basis weight areas. The low basis weight areas can have a basis weight that is greater than about 50%, such as greater than about 70% less than the basis weight of the high basis weight areas. Similarly, the low basis weight areas can have a thickness that is greater than about 50%, such as greater than about 70% less than the thickness of the high basis weight areas. The nonwoven substrates can be made from a fiber furnish that can include any suitable fibers alone or in combination with other solid particles, such as superabsorbent particles. In one aspect, the nonwoven substrate can be made from pulp fibers alone or in combination with synthetic polymer fibers and/or superabsorbent particles. Alternatively, the nonwoven substrate can be made from synthetic polymer fibers alone or in combination with superabsorbent particles. The synthetic polymer fibers, for instance, can comprise polyester fibers. In one particular aspect, the polyester fibers can have a fiber size of from about 0.5 denier to about 15 denier. In one embodiment, the nonwoven substrate can contain superabsorbent particles in combination with polymer synthetic fibers, binder fibers, and pulp fibers, such as softwood fibers. The binder fibers can comprise, for instance, bicomponent fibers having a sheath polymer with a lower melting point.

Nonwoven substrates made according to the present disclosure, for instance, can contain binder fibers in an amount greater than about 5% by weight, such as in an amount greater than about 10% by weight, such as in an amount greater than about 15% by weight, and in an amount less than about 50% by weight, such as in an amount less than about 40% by weight, such as in an amount less than about 30% by weight. The nonwoven substrate can contain polymer synthetic fibers generally in an amount greater than about 3% by weight, such as in an amount greater than about 5% by weight, such as in an amount greater than about 7% by weight, such as in an amount greater than about 10% by weight, and in an amount less than about 75% by weight, such as in an amount less than about 50% by weight, such as in an amount less than about 35% by weight, such as in an amount less than about 30% by weight.

In one aspect, the nonwoven substrate can contain pulp fibers, particularly crosslinked pulp fibers. The crosslinked pulp fibers can be present in the nonwoven substrate in an amount greater than about 5% by weight, such as in an amount greater than about 10% by weight, such as in an amount greater than about 15% by weight, such as in an amount greater than about 20% by weight, and in an amount less than about 60% by weight, such as in an amount less than about 50% by weight.

When present, superabsorbent materials can be incorporated into the nonwoven substrate in an amount greater than about 10% by weight, such as in an amount greater than about 20% by weight, such as in an amount greater than about 30% by weight, and in an amount less than about 90% by weight, such as in an amount less than about 70% by weight, such as in an amount less than about 50% by weight, such as in an amount less than about 40% by weight. In one embodiment, the nonwoven substrate can comprise a multi-layered web in which the superabsorbent materials are all contained in a middle layer that is positioned between a top layer and a bottom layer.

Although substrates made according to the present disclosure can be formed in a wet-lay process, in one embodiment, the nonwoven substrates are formed from a foamed suspension of fibers. The foam, for instance, can have a density of from about 200 g/L to about 600 g/L, such as from about 250 g/L to about 400 g/L when deposited on the forming surface. The foamed suspension, for instance, can contain a foaming agent and water combined with the fibers. The foamed suspension can contain from about 40% to about 80% by volume air when deposited onto the forming surface.

The present disclosure is also directed to a forming wire for producing nonwoven substrates. The forming wire comprises a fabric formed from woven yarns. The fabric includes a top forming surface, including a pattern of porous first zones and porous second zones. The first zones have a porosity greater than a porosity of the second zones. The porosity of the second zones can be at least 50% less, such as at least 60% less, such as at least 70% less, such as at least 80% less, such as at least 90% less, such as at least 95% less than the porosity of the first zones. The second zones can have a width dimension that is greater than about 4 mm, such as greater than about 5 mm, such as greater than about 6 mm, such as greater than about 7 mm, and generally less than about 15 mm, such as less than about 12 mm, such as less than about 10 mm, such as less than about 9 mm. In one aspect, the second zones comprise zones where an additive material has been applied to the fabric.

The present disclosure is also directed to nonwoven substrates made by the process described above. The nonwoven substrates comprise a continuous, nonwoven web having a first surface and a second and opposite surface. The nonwoven web can comprise a blend of fibers containing at least one of cellulose fibers, synthetic polymer fibers, and superabsorbent particles. The nonwoven web can have an average basis weight of from about 30 gsm to about 800 gsm. According to the present disclosure, a topographical pattern can be located on the first surface of the nonwoven web. The pattern can include high basis weight areas and low basis weight areas. The low basis weight areas can have a basis weight that is at least 50% less than a basis weight of the high basis weight areas. The low basis weight areas can have a width of at least 4 mm.

In one embodiment, the nonwoven material can be calendered so as to produce a flat planar sheet with high basis weight areas and low basis weight areas. Once the web is calendered, the high basis weight areas form high density areas and the low basis weight areas form low density areas.

Other features and aspects of the present disclosure are discussed in greater detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present disclosure is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which:

FIG. 1 is one embodiment of a process and system that may be used to produce nonwoven substrates in accordance with the present disclosure;

FIG. 2 is a detailed portion of a component feed system contained in the process illustrated in FIG. 1 ;

FIG. 3 is a plan view of one embodiment of a forming surface in accordance with the present disclosure;

FIG. 4 is a plan view of another embodiment of a forming surface in accordance with the present disclosure;

FIG. 5 is a plan view of another embodiment of a forming surface in accordance with the present disclosure;

FIG. 6 is a plan view of still another embodiment of a forming surface in accordance with the present disclosure;

FIG. 7 is a plan view of another embodiment of a forming surface in accordance with the present disclosure; FIG. 8 is a cross-sectional view of one embodiment of a nonwoven substrate made in accordance with the present disclosure;

FIG. 9 is a plan view of another embodiment of a forming surface in accordance with the present disclosure; and

FIG. 10 is a plan view of a nonwoven substrate made in accordance with the present disclosure using the forming surface as shown in FIG. 9.

Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the disclosure.

DEFINITIONS

As used herein, the term "foam formed product” means a product formed from a suspension including a mixture of a solid, a liquid, and dispersed gas bubbles.

As used herein, the term “foam forming process” means a process for manufacturing a product involving a suspension including a mixture of a solid, a liquid, and dispersed gas bubbles.

As used herein, the term "foaming fluid” means any one or more known fluids compatible with the other components in the foam forming process. Suitable foaming fluids include, but are not limited to, water.

As used herein, the term “foam half life” means the time elapsed until the half of the initial frothed foam mass reverts to liquid water.

As used herein, the term “layer” refers to a structure that provides an area of a substrate in a height direction of the substrate that is comprised of similar components and structure.

As used herein, the term "nonwoven web" means a web having a structure of individual fibers or threads which are interlaid, but not in an identifiable manner as in a knitted web.

As used herein, unless expressly indicated otherwise, when used in relation to material compositions the terms "percent", “%”, "weight percent", or "percent by weight" each refer to the quantity by weight of a component as a percentage of the total except as whether expressly noted otherwise.

The term "personal care absorbent article” refers herein to an article intended and/or adapted to be placed against or in proximity to the body (i.e., contiguous with the body) of the wearer to absorb and contain various liquid, solid, and semi-solid exudates discharged from the body. Examples include, but are not limited to, diapers, diaper pants, training pants, youth pants, swim pants, feminine hygiene products, including, but not limited to, menstrual pads or pants, incontinence products, medical garments, surgical pads and bandages, and so forth.

The term "superabsorbent material" as used herein refers to water-swellable, water-insoluble organic or inorganic materials including superabsorbent polymers and superabsorbent polymer compositions capable, under the most favorable conditions, of absorbing at least about 10 times their weight, or at least about 15 times their weight, or at least about 25 times their weight in an aqueous solution containing 0.9 weight percent sodium chloride.

The term "machine direction" as used herein refers to the direction of travel of the forming surface onto which fibers are deposited during formation of a nonwoven web.

The term "cross-machine direction" as used herein refers to the direction which is perpendicular to both the machine direction and the height direction defined above.

The term "pulp" as used herein refers to fibers from natural sources such as woody and non- woody plants. Woody plants include, for example, deciduous and coniferous trees. Non-woody plants include, for example, cotton, flax, esparto grass, milkweed, straw, jute, hemp, and bagasse. Pulp fibers can include hardwood fibers, softwood fibers, and mixtures thereof.

The term "average fiber length" as used herein refers to an average length of fibers, fiber bundles and/or fiber-like materials determined by measurement utilizing microscopic techniques. A sample of at least 20 randomly selected fibers is separated from a liquid suspension of fibers. The fibers are set up on a microscope slide prepared to suspend the fibers in water. A tinting dye is added to the suspended fibers to color cellulose-containing fibers so they may be distinguished or separated from synthetic fibers. The slide is placed under a Fisher Stereomaster II Microscope-S19642/S19643 Series. Measurements of 20 fibers in the sample are made at 20X linear magnification utilizing a 0-20 mils scale and an average length, minimum and maximum length, and a deviation or coefficient of variation are calculated. In some cases, the average fiber length will be calculated as a weighted average length of fibers (e.g., fibers, fiber bundles, fiber-like materials) determined by equipment such as, for example, a Kajaani fiber analyzer Model No. FS-200, available from Kajaani Oy Electronics, Kajaani, Finland. According to a standard test procedure, a sample is treated with a macerating liquid to ensure that no fiber bundles or shives are present. Each sample is disintegrated into hot water and diluted to an approximately 0.001% suspension. Individual test samples are drawn in approximately 50 to 100 ml portions from the dilute suspension when tested using the standard Kajaani fiber analysis test procedure. The weighted average fiber length may be an arithmetic average, a length weighted average or a weight weighted average and may be expressed by the following equation: where k=maximum fiber length xrfiber length ni=number of fibers having length xi n=total number of fibers measured.

One characteristic of the average fiber length data measured by the Kajaani fiber analyzer is that it does not discriminate between different types of fibers. Thus, the average length represents an average based on lengths of all different types, if any, of fibers in the sample.

As used herein the term "staple fibers" means discontinuous fibers made from synthetic polymers or regenerated cellulose, such as polypropylene, polyester, post consumer recycle (PGR) fibers, polyester, nylon, viscose, rayon, and the like, and those not hydrophilic may be treated to be hydrophilic. Staple fibers may be cut fibers or the like. Staple fibers can have cross-sections that are round, bicomponent, multicomponent, shaped, hollow, or the like.

DETAILED DESCRIPTION

It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only and is not intended as limiting the broader aspects of the present disclosure.

The present disclosure is directed to methods and systems that can produce nonwoven substrates. While the present disclosure provides examples of substrates manufactured through foam-forming, it is contemplated that the methods and apparatuses described herein may be utilized to benefit wet-laid and/or air-laid manufacturing processes.

Each example is provided by way of explanation and is not meant as a limitation. For example, features illustrated or described as part of one embodiment or figure can be used on another embodiment or figure to yield yet another embodiment. It is intended that the present disclosure include such modifications and variations.

When introducing elements of the present disclosure or the preferred embodiment(s) thereof, the articles “a”, “an”, “the" and “said" are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. As used herein, the terminology of “first,” “second,” “third”, etc. does not designate a specified order, but is used as a means to differentiate between different occurrences when referring to various features in the present disclosure. Many modifications and variations of the present disclosure can be made without departing from the spirit and scope thereof. Therefore, the exemplary embodiments described herein should not be used to limit the scope of the invention.

In general, the present disclosure is directed to a process and system for producing nonwoven substrates. The present disclosure is also directed to a unique forming wire for producing the substrates. The nonwoven substrates can be single layer or can be multi-layer. In accordance with the present disclosure, the nonwoven substrates are formed with a pattern of high basis weight areas and low basis weight areas that can provide many advantages and benefits. The nonwoven substrates of the present disclosure can be used in numerous and diverse end use applications. The pattern of high basis weight areas and low basis weight areas can provide significant improved functionality that is tailored for the particular application.

The nonwoven substrates can be used in many different types of applications. For example, the nonwoven substrates can be used to form wiping products. Alternatively, the nonwoven substrates can contain super-absorbent materials and used to form an absorbent core in an absorbent article. In this embodiment, the absorbent article can include a liquid permeable liner, a liquid impermeable outer cover, and an absorbent core made according to the present disclosure positioned between the liner and the outer cover.

In one aspect, for instance, the low basis weight areas are surrounded by the higher basis weight areas and form fluid control canals that can be used to quickly intake and distribute fluids, which can provide advantages when incorporated into absorbent articles, wiping products and the like. The lower basis weight areas can also function as points of greater flexibility to make the high basis weight areas conform to adjacent surfaces. In particular, the low basis weight areas create a much more flexible and shape conforming substrate that behaves as a thinner material, especially in relation to a substrate made entirely from the high basis weight areas. Alternatively, the high basis weight areas can be surrounded by the low basis weight areas.

In addition to the above, the low basis weight areas can be formed with relatively wide sections that can significantly improve the breathability of the material. Substrates made according to the present disclosure can produce an optimum microclimate when contained in an absorbent article by allowing better air exchange through the low basis weight areas. When incorporated into a diaper, an adult incontinence product, or the like, the pattern of high basis weight areas and low basis weight areas can be designed to collect and move away from the body feces and other bodily fluids for protecting the skin and providing a garment that promotes better health.

Nonwoven substrates made according to the present disclosure can also provide enhanced comfort. For instance, the pattern of high basis weight areas and low basis weight areas can provide a "cushion-like” feel to users. The patterns can also be designed for visual appeal or as a signal to a user to highlight some other benefit of the product.

In still another aspect, nonwoven substrates can be made according to the present disclosure and wound into a roll. The roll can then be fed into a converting process for producing various different products, including absorbent articles or wiping products. The low basis weight areas can be designed as tracks or lanes for slitting the nonwoven material into strips or individual pieces. Slitting along the low basis weight areas may enable faster converting speeds and reduced wear on the slitting equipment.

In accordance with the present disclosure, nonwoven substrates made according to the present disclosure can be formed from a wet suspension of fibers and other solid materials. The substrates can be formed in a wet-lay process or in a foam forming process. The wet suspension of fibers and other solid material is deposited onto a specially designed patterned forming wire. The patterned wire has low porosity zones and high porosity zones. The low porosity zones have some porosity (but not non-zero porosity) that is much lower than the high porosity regions. In accordance with the present disclosure, the low porosity zones have a width dimension that is longer than the average length of at least one of the fiber types in the fiber furnish used to form the wet suspension. The porosity within the low porosity zones, however, can be controlled to prevent holes from forming in substrates formed on the forming surface. In this regard, the forming wire is constructed and the process is controlled so as to produce a continuous substrate. Nonwoven substrates formed on the forming surface, for instance, include high basis weight areas and low basis weight areas that correspond to the pattern of high porosity zones and low porosity zones respectively.

Alternatively, the process can be designed to produce nonwoven substrates with holes located at strategic and desired locations The holes can be located in the high basis weight areas or in the low basis weight areas. The holes, for instance, can be used for better fluid control, perhaps to direct fluids into an adjacent layer. The holes can be formed, in one embodiment, by creating areas on the forming surface with zero porosity.

Due in part to the width dimension of the low porosity zones, nonwoven substrates can be produced on the forming surface having dramatic basis weight differences and/or thicknesses which can create products with many different enhanced properties as described above. For example, the basis weight of the low basis weight areas can be greater than about 50% less than the basis weight of the high basis weight areas. In various embodiments, for instance, the low basis weight areas can have a basis weight that is greater than about 60%, such as greater than about 70%, such as greater than about 80%, such as greater than about 90% less than the basis weight of the high basis weight areas. Similarly, the thickness of the low basis weight areas can be greater than about 50%, such as greater than about 60%, such as greater than about 70%, such as greater than about 80%, such as greater than about 90% less than the thickness of the high basis weight areas.

The high basis weight areas can have any suitable basis weight and thickness depending upon the particular application. When forming certain wiping products or absorbent structures, the higher basis weight areas can have a basis weight of greater than about 50 gsm, such as greater than about 80 gsm, such as greater than about 100 gsm, such as greater than about 120 gsm, such as greater than about 140 gsm, and less than about 800 gsm, such as less than about 600 gsm. The thickness of the high basis weight areas can generally be greater than about 0.5 mm, such as greater than about 1 mm, such as greater than about 1 .5 mm, such as greater than about 2 mm, such as greater than about 2.5 mm, such as greater than about 3 mm, such as greater than about 3.5 mm, such as greater than about 4 mm, and less than about 50 mm, such as less than about 30 mm, such as less than about 20 mm.

Alternatively, the nonwoven substrate can be calendered so that the substrate has a uniform thickness but includes high density areas and low density areas. The density of the high basis weight areas can be greater than about 50%, such as greater than about 60%, such as greater than about 70%, such as greater than about 80%, such as greater than about 90% less than the density of the low basis weight areas.

In the past, patterned forming wires have been proposed that can include low drainage regions or topographical structures. For instance, U.S. Patent No. 10,920,374 discloses a three- dimensional papermaking belt, while WO 96/35018 discloses a decorative forming fabric. Both of these references are incorporated herein by reference. Although both references have provided various improvements in the art, the forming wire of the present disclosure offers many advantages and benefits over the forming surfaces disclosed in the references. Further, WO 96/35018 specifically teaches that the width of the lines which comprise the decorative areas and the low drainage areas of the forming surface must have a width such that about 50% or greater of the fibers in the furnish have a fiber length greater than the line width, or discontinuous webs are formed containing undesirable holes.

As described in more detail below, however, the forming surface of the present disclosure can, in one aspect, contain low porosity zones having a width that can be greater than the fiber length of the longest fibers in the furnish. Not only has this design been found to provide numerous advantages and benefits, but can also be incorporated into a process for forming nonwoven substrates without the formation of holes. In addition, when nonwoven substrates are made according to the present disclosure using a foam forming process, many different fibers, fiber sizes, and materials can be processed alone or together. Thus, nonwoven substrates can be made according to the present disclosure that have unique properties, basis weights, thicknesses, and the like.

Nonwoven substrates made according to the present disclosure are formed from a wet suspension of fibers and optionally other solid material. The process used to form the nonwoven substrate can be a wet-lay process, an air forming process, or a foam forming process. The nonwoven substrate can be a single layer material or can be a multi-layer material. Referring to FIG. 1, for exemplary purposes only, one embodiment of a process that may be used to form nonwoven substrates in accordance with the present disclosure is shown. The process and system as illustrated in FIG. 1 can be a wet-lay process. Various benefits and advantages can be achieved, however, when using a foam forming process. Consequently, the system and process illustrated in FIG. 1 will be described in greater detail below as a foam forming process.

Referring to FIGS. 1 and 2, in one embodiment, the present disclosure relates to a method and apparatus 10 that can form a substrate 12. FIG. 1 provides a schematic of an exemplary apparatus 10 that can be used as part of a foam forming process to manufacture a substrate 12 that is a foam formed product. The apparatus 10 can include a first tank 14 configured for holding a first fluid supply 16. In some embodiments, the first fluid supply 16 can be a foam. The first fluid supply 16 can include a fluid provided by a supply of fluid 18. In some embodiments, the first fluid supply 16 can include a plurality of fibers provided by a supply of fibers 20, however, in other embodiments, the first fluid supply 16 can be free from a plurality of fibers. The first fluid supply 16 can also include a surfactant provided by a supply of surfactant 22. In some embodiments, the first tank 14 can include a mixer 24, as will be discussed in more detail below. The mixer 24 can mix (e.g., agitate) the first fluid supply 16 to mix the fluid, fibers (if present), and surfactant with air, or some other gas, to create a foam. The mixer 24 can also mix the foam with fibers (if present) to create a foam suspension of fibers in which the foam holds and separates the fibers to facilitate a distribution of the fibers within the foam (e.g., as an artifact of the mixing process in the first tank 14). Uniform fiber distribution can promote desirable substrate properties including, for example, strength and the visual appearance of quality.

The apparatus 10 can also optionally include a second tank 26 configured for holding a second fluid supply 28. In some embodiments, the second fluid supply 28 can be a foam. The second fluid supply 28 can include a fluid provided by a supply of fluid 30 and a surfactant provided by a supply of surfactant 32. In some embodiments, the second fluid supply 28 can include a plurality of fibers in addition to or as an alternative to the fibers being present in the first fluid supply 16. In some embodiments, the second tank 26 can include a mixer 34. The mixer 34 can mix the second fluid supply 28 to mix the fluid and surfactant with air, or some other gas, to create a foam.

For either or both the first tank 14 and the second tank 26, the first fluid supply 16 or the second fluid supply 28 can be acted upon to form a foam. In some embodiments, the foaming fluid and other components are acted upon so as to form a porous foam having an air content greater than about 50% by volume and desirably an air content greater than about 60% by volume. In certain aspects, the highly-expanded foam is formed having an air content of between about 60% and about 95% and in further aspects between about 65% and about 85%. In certain embodiments, the foam may be acted upon to introduce air bubbles such that the ratio of expansion (volume of air to other components in the expanded stable foam) is greater than 1 :1 and in certain embodiments the ratio of air:other components can be between about 1.1 :1 and about 20:1 or between about 1 .2:1 and about 15:1 or between about 1.5:1 and about 10:1 or even between about 2:1 and about 5:1.

The foam can be generated by one or more means known in the art. Examples of suitable methods include, without limitation, aggressive mechanical agitation such as by mixers 24, 34, injection of compressed air, and so forth. Mixing the components through the use of a high-shear, high-speed mixer is particularly well suited for use in the formation of the desired highly-porous foams. Various high-shear mixers are known in the art and believed suitable for use with the present disclosure. High-shear mixers typically employ a tank holding the foam precursor and/or one or more pipes through which the foam precursor is directed. The high-shear mixers may use a series of screens and/or rotors to work the precursor and cause aggressive mixing of the components and air. In a particular embodiment, the first tank 14 and/or the second tank 26 is provided having therein one or more rotors or impellors and associated stators. The rotors or impellers are rotated at high speeds in order to cause flow and shear. Air may, for example, be introduced into the tank at various positions or simply drawn in by the action of the mixers 24, 34. While the specific mixer design may influence the speeds necessary to achieve the desired mixing and shear, in certain embodiments suitable rotor speeds may be greater than about 500 rpm and, for example, be between about 1000 rpm and about 6000 rpm or between about 2000 rpm and about 4000 rpm In certain embodiments, with respect to rotor based high-shear mixers, the mixer(s) 24, 34 may be run with the foam until the disappearance of the vortex in the foam or a sufficient volume increase is achieved.

In addition, it is noted the foaming process can be accomplished in a single foam generation step or in sequential foam generation steps for the first tank 14 and/or the second tank 26. For example, in one embodiment, all of the components of the first fluid supply 16 in the first tank 14 (e.g., the supply of the fluid 18, fibers 20, and surfactant 22) may be mixed together to form a slurry from which a foam is formed. Alternatively, one or more of the individual components may be added to the foaming fluid, an initial mixture formed (e.g. a dispersion or foam), after which the remaining components may be added to the initially foamed slurry and then all of the components acted upon to form the final foam. In this regard, the fluid 18 and surfactant 22 may be initially mixed and acted upon to form an initial foam prior to the addition of any solids. Fibers, if desired, may then be added to the water/surfactant foam and then further acted upon to form the final foam. As a further alternative, the fluid 18 and fibers 20, such as a high density cellulose pulp sheet, may be aggressively mixed at a higher consistency to form an initial dispersion after which the foaming surfactant, additional water and other components, such as synthetic fibers, are added to form a second mixture which is then mixed and acted upon to form the foam. The foam density of the foam forming the first fluid supply 16 in the first tank 14 and/or the foam forming the second fluid supply 28 in the second tank 26 can vary depending upon the particular application and various factors, such as the fiber stock used. In some implementations, for example, the foam density of the foam can be greater than about 100 g/L, such as greater than about 250 g/L, such as greater than about 300 g/L. The foam density is generally less than about 800 g/L, such as less than about 500 g/L, such as less than about 400 g/L, such as less than about 350 g/L. In some implementations, for example, a lower density foam is used having a foam density of generally less than about 350 g/L, such as less than about 340 g/L, such as less than about 330 g/L.

In some embodiments, the apparatus 10 can also include a first pump 36 and a second pump 38. The first pump 36 can be in fluid communication with the first fluid supply 16 and can be configured for pumping the first fluid supply 16 to transfer the first fluid supply 16. The second pump 38 can be in fluid communication with the second fluid supply 28 and can be configured for pumping the second fluid supply 28 to transfer the second fluid supply 28. In some embodiments, the first pump 36 and/or the second pump 38 can be a progressive cavity pump or a centrifugal pump, however, it is contemplated that other suitable types of pumps can be used. Additionally, as discussed further below, in some embodiments, the apparatus can be provided with a single pump that can pump a single fluid supply into a first fluid supply 16 and a second fluid supply 28.

As depicted in FIGS. 1 and 2, the apparatus 10 can also optionally include a component feed system 40. The component feed system 40, for instance, can be used to feed a particulate material into the fiber furnish, such as superabsorbent particles. When forming a substrate solely from fibers, however, the component feed system 40 is not needed including use of the second fluid supply 28. When present, the component feed system 40 can include a component supply area 42 for receiving a supply of a component 44 as shown in the partial cut-away portion of the component supply area 42 illustrated in FIG. 2. The component feed system 40 can also include an outlet conduit 46. The outlet conduit 46 can be circular in cross-sectional shape, or can be configured in a rectangular fashion such as to form a slot. The component feed system 40 can also include a hopper 48. The hopper 48 can be coupled to the component supply area 42 and can be utilized for refiling the supply of the component 44 to the component supply area 42.

In some embodiments, the component feed system 40 can include a bulk solids pump. Some examples of bulk solids pumps that may be used herein can include systems that utilize screws/augers, belts, vibratory trays, rotating discs, or other known systems for handling and discharging the supply of the component 44. Other types of feeders can be used for the component feed system 40, such as, for example, an ingredient feeder, such as those manufactured by Christy Machine & Conveyor, Fremont, Ohio. The component feed system 40 can also be configured as a conveyor system in some embodiments.

The component feed system 40 can also include a fluid control system 50. The fluid control system 50 can be configured to control the gas entrainment into the fluid supply into which the supply of the component 44 is being placed. In some embodiments, the fluid control system 50 can include a housing 52. The housing 52 can form a pressurized seal volume around the component feed system 40. In other embodiments, the fluid control system 50 can be formed as an integral part to the structure component feed system 40 itself, such that a separate housing 52 surrounding the component feed system 40 may not be required. As depicted in FIGS. 1 and 2, the fluid control system 50 can also include a bleed orifice 54 in some embodiments.

The supply of the component 44 can be in the form of a particulate and/or a fiber. In one embodiment as described herein, the supply of the component 44 can be superabsorbent material (SAM) in particulate form. In some embodiments, SAM can be in the form of a fiber. Of course, other types of components, as described further below, are also contemplated as being utilized in the apparatus 10 and methods as described herein. The component feed system 40 as described herein can be particularly beneficial for a supply of component 44 that is most suitably maintained in a dry environment with minimal of exposure to fluid or foam utilized in the apparatus 10 and methods described herein.

In some embodiments, the apparatus 10 and methods described herein can include a first mixing junction 56 and a second mixing junction 58. In preferred embodiments, the first mixing junction 56 can be an eductor. The first mixing junction 56 can be in fluid communication with the outlet conduit 46 of the component feed system 40 and in fluid communication with the second fluid supply 28. The first mixing junction 56 can be configured as a co-axial eductor.

The first mixing junction 56 can mix the supply of the component 44 from the component feed system 40 with the second fluid supply 28.

Referring back to FIG. 1 , the apparatus 10 can include a second mixing junction 58 in some embodiments. The second mixing junction 58 can provide the functionality of mixing the second fluid supply 28 including the component from the supply of the component 44 with the first fluid supply 16. As the second fluid supply 28 including the component from the supply of the component 44 exits the discharge 64 of the first mixing junction 56 it can be transferred to the second mixing junction 58. The first fluid supply 16 can be delivered to the second mixing junction 58 by the first pump 36. The second mixing junction 58 can mix the first fluid supply 16 and any of its components (e.g., fluid 18, fibers 20, surfactant 22) with the second fluid supply 28 and any of its components (e.g., fluid 30, surfactant 32) and the component from the supply of the component 44 to provide a resultant slurry 76. The resultant slurry 76 can be transferred from the second mixing junction 58 through a discharge 78 of the second mixing junction 58 and to a headbox 80.

The headbox 80 can be provided to transfer the resultant slurry 76 to form a substrate 12. The headbox 80 can have a machine direction 81 and a cross direction 83. The machine direction 81 is in the direction of the transfer of the resultant slurry 76 through the headbox 80.

From the headbox 80, the wet slurry 76 is deposited onto a forming surface 94 made in accordance with the present disclosure. As will be described in greater detail below, the forming surface 94 includes at least one high porosity zone in combination with at least one low porosity zone that is used to produce nonwoven substrates having at least one high basis weight area and at least one low basis weight area.

In the embodiment illustrated in FIG. 1, the forming surface 94 is shown in a horizonal position. In alternative embodiments, the forming surface 94 can be placed at an angle to the headbox 80 such that the slurry 76 moves in an upward motion once deposited onto the forming surface 94. The forming surface 94, for instance, can be positioned at an angle to the horizontal of greater than about 5°, such as greater than about 10°, such as greater than about 15°, and generally less than about 50°, such as less than about 40°, such as less than about 30°, such as less than about 20°. The headbox 80 can be designed to produce single layer substrates or can be used to produce multilayer substrates Substrates 12 can be made according to the present disclosure, for instance, having two layers, three layers, four layers, five layers, or the like. Each layer can have a different fiber furnish if desired.

Once the slurry 76 is deposited onto the forming surface 94, fluids are removed from the suspension for forming a nonwoven substrate. In this regard, the forming surface 94 can be a foraminous sheet that is porous and can at least in part be made from a woven belt or screen. The system can further include a dewatering system 96 that can be configured to remove liquids from the slurry 76 through the forming surface 94. The dewatering system 96, for instance, can provide a vacuum to the slurry 76 to pull fluids from the slurry for forming a consolidated substrate 12.

As shown in FIG. 1, the process can also include a drying system 98. The drying system 98 can be configured to dry the newly formed nonwoven substrate 12. In general, any suitable dryer can be incorporated into the drying system 98. The drying system 98, for instance, can be a through-air dryer, one or a series of heated drums, an oven, or the like. The process can further include a winding system 99 that can be configured to wind the substrate 12 after drying into a roll.

Referring now to FIGS. 3-7, various embodiments of forming surfaces 94 made in accordance with the present disclosure are shown. Referring to FIG. 3, for instance, a forming surface 94 is illustrated including a pattern of porous first zones 102 and porous second zones 104. The first zones 102 have a porosity greater than a porosity of the second zones 104. The machine direction 100 is also shown in FIG. 3 indicating the movement of the forming surface 94 for conveying nonwoven substrates 12 downstream. Consequently, the porous second zones 104 extend in the cross-machine direction. In other embodiments, however, the porous second zones 104 may extend in the machine direction or can extend at a diagonal to the machine direction.

In accordance with the present disclosure, the porous second zones 104 have a non-zero porosity but have a porosity much less than the porosity of the first zones 102. For instance, the porosity of the second zones 104 can be at least about 50% less, such as at least about 60% less, such as at least about 70% less, such as at least about 80% less, such as at least about 90% less, such as at least about 95% less, and up to about 99.5% less than the porosity of the first zones 102. Consequently, as the slurry 76 is deposited onto the forming surface 94 and dewatered, the fibers and/or particulate material contained in the slurry preferentially accumulate on the forming surface 94 where the higher porosity first zones 102 are located. The porosity of the second zones 104 and the process is controlled such that at least some solid matter also accumulates on the second zones 104 for producing continuous sheets. In this manner, nonwoven substrates 12 are formed that have a pattern of high basis weight areas and low basis weight areas in which the low basis weight areas have a dramatically reduced basis weight in relation to the high basis weight areas.

The basis weight of the high basis weight areas and the basis weight of the low basis weight areas can vary depending upon the particular application and the process conditions. The high basis weight areas can generally have a basis weight of greater than about 30 gsm, such as greater than about 50 gsm, such as greater than about 80 gsm, such as greater than about 100 gsm, such as greater than about 120 gsm, such as greater than about 150 gsm, such as greater than about 180 gsm, such as greater than about 200 gsm, such as greater than about 250 gsm, such as greater than about 270 gsm, such as greater than about 300 gsm, such as greater than about 320 gsm, such as greater than about 350 gsm, such as greater than about 370 gsm, such as greater than about 400 gsm, such as greater than about 420 gsm, such as greater than about 450 gsm, such as greater than about 470 gsm, such as greater than about 500 gsm. The basis weight of the high basis weight areas is generally less than about 800 gsm, such as less than about 750 gsm, such as less than about 700 gsm, such as less than about 650 gsm, such as less than about 600 gsm, such as less than about 550 gsm, such as less than about 500 gsm, such as less than about 450 gsm, such as less than about 400 gsm, such as less than about 350 gsm, such as less than about 300 gsm, such as less than about 250 gsm, such as less than about 200 gsm, such as less than about 150 gsm, such as less than about 100 gsm, such as less than about 80 gsm. As described above, the low basis weight areas generally have a basis weight that can be anywhere from about 40% to about 99% less than the basis weight of the high basis weight areas including all increments of 1% therebetween. The nonwoven substrate can also have an average basis weight that averages the basis weight of the high basis weight areas and the low basis weight areas. The average basis weight of the nonwoven substrate can be from about 30 gsm to about 800 gsm, such as from about 40 gsm to about 600 gsm.

In the embodiment illustrated in FIG. 3, the low porous second zones 104 form elongated columns on the forming surface 94. In FIG. 3, the elongated columns 104 are linear and parallel to each other. In other embodiments, however, the columns 104 can be curved and/or include a plurality of curvatures over their length.

In accordance with the present disclosure, the porous second zones 104 can have a width that is generally longer than any of the fibers contained in the slurry or suspension 76. For example, the slurry 76 can include one fiber type or a plurality of different types of fibers. Each fiber type can have an average fiber length. The width of the second zones 104 can be greater than the average fiber length of at least one of the fiber types, and, in one embodiment, greater than the longest type of fiber contained in the slurry. In this manner, dramatic differences in basis weight can be formed in nonwoven substrates that produce many beneficial properties and advantages.

For example, the width of the second zones 104 can generally be greater than about 0.5 mm, such as greater than about 1 mm, such as greater than about 1 .5 mm, such as greater than about 2 mm, such as greater than about 2.5 mm, such as greater than about 3 mm, such as greater than about 4 mm, such as greater than about 5 mm, such as greater than about 6 mm, such as greater than about 7 mm, such as greater than about 8 mm, such as greater than about 9 mm. The width of the second zones 104 is generally less than about 15 mm, such as less than about 12 mm, such as less than about 11 mm, such as less than about 10 mm, such as less than about 9 mm. The width of the second zones 104 as described above generally refers to at least one area of the second zones 104 possessing the above width dimensions. In the embodiment illustrated in FIG. 3, the second zones 104 have a uniform width. In other embodiments, however, the width can vary as long as at least a portion of the width is greater than the average fiber length of at least one of the fiber types. In one embodiment, the second zones 104 have a width greater than the longest fiber length over at least 10% of the length of the second zones 104. For example, the second zones 104 can have a width greater than the longest fiber length over at least about 20% of the length, such as over at least about 30% of the length, such as over at least about 40% of the length, such as over at least about 50% of the length, such as over at least about 60% of the length, such as over at least about 70% of the length, such as over at least about 80% of the length.

The foraminous sheet or forming wire that produces the forming surface 94 can be made in any suitable manner. In one embodiment, for instance, the forming surface 94 can be formed from woven yarns that form a fabric. The density of the weave can be increased in order to form the low porous second zones 104. The yarns can be made from polymer fibers, metal fibers, or combinations thereof.

Alternatively, the second zones 104 can be created by depositing a material on the forming surface 94 for blocking flow through the forming surface while still creating low porosity areas. In one aspect, for instance, a polymer material or additive material, such as a thermoplastic or thermoset polymer, can be applied to the fabric for forming the second zones 104. The polymer material can be applied to the fabric in a manner that does not completely block flow through the fabric. Alternatively, the polymer can be applied to the fabric and holes, such as pin holes, can later be formed into the polymer layer to form the second zones 104.

In one particular embodiment, the second zones 104 are created by applying an additive material to the fabric using a three-dimensional printer. The 3-D printer can apply the additive material in different layers onto the fabric until a desired pattern is produced and until the second zones 104 have a desired porosity. The additive material can be applied to the woven fabric so as to impregnate the fabric, embedding itself into the interstices of the fabric.

For example, in one embodiment, an additive material is melted and applied to the fabric by a three-dimensional printer. The melted polymer partially or fully flows around the individual yarns that make up the fabric ensuring a strong mechanical bond A second layer is then applied to the fabric to reach a desired magnitude of the design. The use of 3-D printers can offer various advantages and benefits. For instance, 3-D printers can apply the additive material as large discrete elements or as small elements creating an intricate design. Of particular advantage, it was discovered that the additive material can be applied to the fabric so that the second zones 104 are durable and capable of withstanding process conditions and movement of the forming surface around rollers as a conveyor.

The porosity of the second zones 104 can vary depending upon the particular application and the desired result. In general, the second zones 104 can be created such that the second zones have less than about 15% open area in relation to the total surface area of the second zones. For instance, the open area of the second zones 104 can be less than about 12%, such as less than about 10%, such as less than about 8%, such as less than about 6%, such as less than about 5%, such as less than about 4%, such as less than about 3%. The open area of the second zones 104 is generally greater than about 0.5%, such as greater than about 1%, such as greater than about 2%.

The open area on the second zones 104 can be comprised of passages through the forming surface 94 having any suitable size and shape. For instance, the open area can be comprised of microholes that densely populate the second zones 104. Alternatively, the open area can be comprised of larger pin holes that are spaced along the second zones 104. The size and pattern of holes that extend through the second zones 104 can be controlled and optimized for a particular application.

In one embodiment, the porous second zones 104 can be formed on the forming surface 94 without creating raised areas on the forming surface. In fact, in one embodiment, various advantages and benefits can be obtained if the forming surface 94 forms a generally planar surface such that the second zones 104 are raised above the surface of the first zones 102 by less than about 0.5 mm, such as less than about 0.3 mm, such as less than about 0.1 mm, such as less than about 0.05 mm. Having raised features on the forming surface 94, for instance, can pose additional challenges for processing nonwoven substrates. In fact, it was discovered that raised areas were not needed in order to create substrates having high and low basis weight areas.

As shown in FIG. 3, the second zones 104 are spaced apart along the machine direction 100 of the forming surface 94. The spacing between the second zones 104 can vary depending upon the particular application and the desired result. In one embodiment, for instance, the spacing between the second zones 104 (measured an edge of one second zone to an adjacent edge of a second zone) is greater than about 1 mm, such as greater than about 2 mm, such as greater than about 3 mm, such as greater than about 5 mm, such as greater than about 6 mm, such as greater than about 7 mm, such as greater than about 8 mm, such as greater than about 9 mm, such as greater than about 10 mm, such as greater than about 11 mm, such as greater than about 12 mm, such as greater than about 13 mm, such as greater than about 14 mm, such as greater than about 15 mm, such as greater than about 20 mm, such as greater than about 30 mm, such as greater than about 40 mm, such as greater than about 50 mm, such as greater than about 60 mm, such as greater than about 70 mm, such as greater than about 80 mm, and generally less than about 500 mm, such as less than about 200 mm, such as less than about 100 mm, such as less than about 70 mm, such as less than about 50 mm, such as less than about 30 mm, such as less than about 20 mm, such as less than about 18 mm, such as less than about 16 mm, such as less than about 14 mm, such as less than about 12 mm, such as less than about 10 mm, such as less than about 5 mm.

Once the slurry or suspension of fibers and/or other solid materials is deposited onto the forming surface 94 as shown in FIG. 3, fluids are drained causing a nonwoven substrate 12 to form that includes areas of high basis weight and low basis weight corresponding to the porous first zones 102 and the porous second zones 104 respectively. Referring to FIG. 8, for instance, a cross-section of a nonwoven substrate 12 made on the forming surface 94 as shown in FIG. 3 is illustrated. As shown, the nonwoven substrate 12 includes high basis weight areas 106 that separate low basis weight areas 108. The high basis weight areas 106 are formed where the first zones 102 are located and the low basis weight areas 108 are formed where the second zones 104 are located on the forming surface 94. As shown in FIG. 8, the low basis weight areas form fluid control canals in the substrate that produce many advantages and benefits. The fluid control canals 108, for instance, can quickly intake and distribute fluids that come into contact with the substrate 12. The low basis weight canals 108 can also greatly increase the flexibility of the substrate 12 such that the substrate 12 more readily conforms to an adjacent surface, such as the body of a user. The low basis weight areas 108 improve the feel of the substrate 12 and greatly enhance the drape properties of the substrate.

When incorporated into absorbent articles, the low basis weight areas 108 can improve breathability and allow for better air exchange while the absorbent article is being worn by a user. When incorporated into an incontinence product, such as a diaper, the low basis weight areas can be used to collect body fluids, such as runny feces, and remove the body fluids from the skin of the user. Thus, the nonwoven substrate 12 when incorporated into an absorbent article can greatly enhance skin health. The high basis weight areas 106, on the other hand, are well suited for absorbing great amounts of fluid and also can provide the substrate with a cushion-like feel. In addition, the substrate 12 can have an overall visual appeal, depending upon the pattern of the low basis weight areas 108.

Referring to FIGS. 4-7, further embodiments of forming surfaces that may be constructed in accordance with the present disclosure are shown. Like reference numerals have been used to indicate similar elements. Referring to FIG. 4, for instance, the forming surface 94 includes a high porous first zone 102 that surrounds low porous second zones 104. In this embodiment, the second zones 104 have an X-like shape. The second zones 104, for instance, can be in the shape of any suitable symbol, letter, number, geometric shape, or the like.

Referring to FIG. 5, the second zones 104 are in the shape of curved or wavy lines that form discrete high porous first zones 102. The high porous first zones 102, for instance, have an eye-like shape. In other embodiments, the low porous second zones 104 may not intersect such that the high porous first zones 102 do not form individual cells and instead extend along the length of the forming surface 94.

Referring to FIG. 6, in this embodiment, the low porous second zones 104 are in the shape of hexagons that form a honeycomb pattern on the forming surface 94. The high porous first zones 102 form individual cells within each hexagon. In addition to having a hexagon shape, the low porous second zones 104 can be circular, in the shape of triangles, squares, rectangles, pentagons, octagons, and the like. In this manner, the low porous zones form a grid-like pattern in the nonwoven substrate. Alternatively, the high porous zones can form the grid-like pattern that surround cells of low porous zones.

Referring to FIG. 7, still another embodiment of a forming surface 94 made in accordance with the present disclosure is shown. In this embodiment, the low porous second zones 104 form discrete shapes within the high porous first zones 102. In this embodiment, the discrete shapes 104 are in the form of circles. Alternatively, the low porosity second zones 104 can have any suitable shape, such as ovals, squares, triangles, or random shapes. In still another embodiment, the pattern can be reversed such that the high porous second zones form discrete shapes within the low porous first zones.

The circles 104, for instance, can have a diameter of greater than about 2 mm, such as greater than about 4 mm, such as greater than about 6 mm, such as greater than about 8 mm, such as greater than about 10 mm, and less than about 25 mm, such as less than about 20 mm, such as less than about 15 mm. The circle spacing can be greater than about 3 mm, such as greater than about 5 mm, such as greater than about 7 mm, such as greater than about 10 mm, and less than about 30 mm, such as less than about 28 mm, such as less than about 26 mm in one embodiment.

Referring to FIGS. 9 and 10, still another embodiment of a forming surface 94 (FIG. 9) is shown in conjunction with a nonwoven substrate 12 (FIG. 10) that was created on the forming surface 94. As shown in FIG. 9, the forming surface 94 includes high porosity or first zones 102 separated by the low porous second zones 104. In this embodiment, the low porous zones 104 are in the form of strips or parallel lines that are discontinuous, meaning that there is a pattern of high porous zones within the low porous zones 104. In this embodiment, for instance, high porous discrete shapes or dots are present within the low porous zones 104. In this manner, it is believed that the low porous zones 104 can have a greater width while still producing a nonwoven substrate with continuity and integrity.

For instance, a nonwoven web 12 made using the forming surface 94 as shown in FIG. 9 is illustrated in FIG. 10. As shown in FIG. 10, the nonwoven substrate 12 includes high basis weight areas 106 separated by low basis weight areas 108. The low basis weight areas 108 are in the form of discontinuous strips that include a pattern of tufts formed into the strips in the form of discrete shapes. In one aspect, the low basis weight areas 108 or strips can have a width of greater than about 5 mm, such as greater than about 8 mm, such as greater than about 10 mm, such as greater than about 12 mm, and less than about 40 mm, such as less than about 30 mm, such as less than about 20 mm, such as less than about 18 mm.

The low basis weight areas 108 as shown in FIG. 10 are particularly well suited to serve as slit lanes for slitting the nonwoven substrate 94. The low basis weight areas 108, for instance, are easier to cut or slit thereby enabling faster converting speeds during a slitting process and reducing wear on slitting equipment. In one embodiment, for instance, the low basis weight areas 108 can form multiple lanes for slitting the nonwoven substrate 12 into a plurality of strips or pieces. The pattern of tufts present in the low basis weight areas 108 provide some strength or integrity to the low basis weight areas while permitting wider lanes for slitting. In general, the pattern of the low porous second zones 104 occupy less than about 90% of the surface area of the forming surface 94. For instance, the low porous second zones 104 can occupy less than about 50%, such as less than about 40%, such as less than about 30%, such as less than about 20% of the surface area of the forming surface. The low porous second zones generally occupy greater than about 5%, such as greater than about 10%, such as greater than about 15%, such as greater than about 20%, such as greater than about 25%, such as greater than about 30% of the surface area of the forming surface 94.

The high porous zones can occupy greater than about 5%, such as greater than about 10%, such as greater than about 25%, such as greater than about 40%, such as greater than about 50%, such as greater than about 60%, such as greater than about 70%, such as greater than about 80%, such as greater than about 90% of the surface area of the forming surface and less than about 90%, such as less than about 80%, such as less than about 70%, such as less than about 50%, such as less than about 30%, such as less than about 10% of the surface area of the forming surface.

As described above, the nonwoven substrates made according to the present disclosure can be formed according to a wet-lay process, a foam forming process, or an air forming process. The foam forming process can provide various advantages. Foam forming processes, for instance, can more easily process longer fibers, require less water to form the webs, and can require less energy to dry the webs in comparison to a wet lay process.

When forming the nonwoven substrate according to a foam forming process, the wet slurry 76 can be a foamed suspension of fibers alone or in combination with other solid materials. In some embodiments, the foaming fluid can comprise between about 85% to about 99.99% of the foam (by weight). In some embodiments, the foaming fluid used to make the foam can comprise at least about 85% of the foam (by weight). In certain embodiments, the foaming fluid can comprise between about 90% and about 99.9% % of the foam (by weight). In certain other embodiments, the foaming fluid can comprise between about 93% and 99.5% of the foam or even between about 95% and about 99.0% of the foam (by weight). In preferred embodiments, the foaming fluid can be water; however, it is contemplated that other processes may utilize other foaming fluids.

The foam forming processes as described herein can utilize one or more foaming agents, such as surfactants, in order to form the foam. The fibers and surfactant, together with the foaming liquid and any additional components, can form a stable dispersion capable of substantially retaining a high degree of porosity for longer than the drying process. In this regard, the surfactant is selected so as to provide a foam having a foam half life of at least 2 minutes, more desirably at least 5 minutes, and most desirably at least 10 minutes. A foam half life can be a function of surfactant types, surfactant concentrations, foam compositions/solid level and mixing power/air content in a foam. The foaming surfactant used in the foam can be selected from one or more known in the art that are capable of providing the desired degree of foam stability. In this regard, the foaming surfactant can be selected from anionic, cationic, nonionic and amphoteric surfactants provided they, alone or in combination with other components, provide the necessary foam stability, or foam half life. As will be appreciated, more than one surfactant can be used, including different types of surfactants, as long as they are compatible, and more than one surfactant of the same type. For example, a combination of a cationic surfactant and a nonionic surfactant or a combination of an anionic surfactant and a nonionic surfactant may be used in some embodiments due to their compatibilities. However, in some embodiments, a combination of a cationic surfactant and an anionic surfactant may not be satisfactory to combine due to incompatibilities between the surfactants.

Anionic surfactants believed suitable for use with the present disclosure include, without limitation, anionic sulfate surfactants, alkyl ether sulfonates, alkylaryl sulfonates, or mixtures or combinations thereof. Examples of alkylaryl sulfonates include, without limitation, alkyl benzene sulfonic acids and their salts, dialkylbenzene disulfonic acids and their salts, dialkylbenzene sulfonic acids and their salts, alkylphenol sulfonic acids/condensed alkylphenol sulfonic acids and their salts, or mixture or combinations thereof. Examples of additional anionic surfactants believed suitable for use in the present disclosure include alkali metal sulforicinates, sulfonated glyceryl esters of fatty acids such as sulfonated monoglycerides of coconut oil acids, salts of sulfonated monovalent alcohol esters such as sodium oleylisethianate, metal soaps of fatty acids, amides of amino sulfonic acids such as the sodium salt of oleyl methyl tauride, sulfonated products of fatty acids nitriles such as palmitonitrile sulfonate, alkali metal alkyl sulfates such as sodium lauryl sulfate, ammonium lauryl sulfate or triethanolamine lauryl sulfate, ether sulfates having alkyl groups of 8 or more carbon atoms such as sodium lauryl ether sulfate, ammonium lauryl ether sulfate, sodium alkyl aryl ether sulfates, and ammonium alkyl aryl ether sulfates, sulphuric esters of polyoxyethylene alkyl ether, sodium salts, potassium salts, and amine salts of alkylnapthylsulfonic acid. Certain phosphate surfactants including phosphate esters such as sodium lauryl phosphate esters or those available from the Dow Chemical Company under the tradename TRITON are also believed suitable for use herewith. A particularly desired anionic surfactant is sodium dodecyl sulfate (SDS).

Cationic surfactants are also believed suitable for use with the present disclosure for manufacturing some embodiments of substrates. In some embodiments, such as those including superabsorbent material, cationic surfactants may be less preferable to use due to potential interaction between the cationic surfactant(s) and the superabsorbent material, which may be anionic. Foaming cationic surfactants include, without limitation, monocarbyl ammonium salts, dicarbyl ammonium salts, tricarbyl ammonium salts, monocarbyl phosphonium salts, dicarbyl phosphonium salts, tricarbyl phosphonium salts, carbylcarboxy salts, quaternary ammonium salts, imidazolines, ethoxylated amines, quaternary phospholipids and so forth. Examples of additional cationic surfactants include various fatty acid amines and amides and their derivatives, and the salts of the fatty acid amines and amides. Examples of aliphatic fatty acid amines include dodecylamine acetate, octadecylamine acetate, and acetates of the amines of tallow fatty acids, homologues of aromatic amines having fatty acids such as dodecylanalin, fatty amides derived from aliphatic diamines such as undecylimidazoline, fatty amides derived from aliphatic diamines such as undecylimidazoline, fatty amides derived from disubstituted amines such as oleylaminodiethylamine, derivatives of ethylene diamine, quaternary ammonium compounds and their salts which are exemplified by tallow trimethyl ammonium chloride, dioctadecyldimethyl ammonium chloride, didodecyldimethyl ammonium chloride, dihexadecyl ammonium chloride, alkyltrimethylammonium hydroxides, dioctadecyldimethylammonium hydroxide, tallow trimethylammonium hydroxide, trimethylammonium hydroxide, methylpolyoxyethylene cocoammonium chloride, and dipalmityl hydroxyethylammonium methosulfate, amide derivatives of amino alcohols such as beta-hydroxylethylstearylamide, and amine salts of long chain fatty acids. Further examples of cationic surfactants believed suitable for use with the present disclosure include benzalkonium chloride, benzethonium chloride, cetrimonium bromide, distearyldimethylammonium chloride, tetramethylammonium hydroxide, and so forth.

Nonionic surfactants believed suitable for use in the present disclosure include, without limitation, condensates of ethylene oxide with a long chain fatty alcohol or fatty acid, condensates of ethylene oxide with an amine or an amide, condensation products of ethylene and propylene oxides, fatty acid alkylol amide and fatty amine oxides. Various additional examples of non-ionic surfactants include stearyl alcohol, sorbitan monostearate, octyl glucoside, octaethylene glycol monododecyl ether, lauryl glucoside, cetyl alcohol, cocamide MEA, monolaurin, polyoxyalkylene alkyl ethers such as polyethylene glycol long chain (12-14C) alkyl ether, polyoxyalkylene sorbitan ethers, polyoxyalkylene alkoxylate esters, polyoxyalkylene alkylphenol ethers, ethylene glycol propylene glycol copolymers, polyvinyl alcohol, alkylpolysaccharides, polyethylene glycol sorbitan monooleate, octylphenol ethylene oxide, and so forth. There may be advantages to using one or more nonionic surfactants when the nonwoven substrate contains super-absorbent materials.

The foaming surfactant can be used in varying amounts as necessary to achieve the desired foam stability and air-content in the foam. In certain embodiments, the foaming surfactant can comprise between about 0.005% and about 5% of the foam (by weight). In certain embodiments the foaming surfactant can comprise between about 0.05% and about 3% of the foam or even between about 0.05% and about 2% of the foam (by weight). The fibers and/or other solid material used to form nonwoven substrates in accordance with the present disclosure can vary depending upon the particular application and the desired result. For instance, the nonwoven substrates can be formed from pulp fibers, other natural fibers such as cotton fibers, regenerated cellulose fibers, synthetic polymer fibers, binder fibers, superabsorbent particles, and mixtures thereof. When producing tissue products, for instance, the nonwoven substrate can contain pulp fibers in an amount greater than about 90% by weight. When producing wiping products, the nonwoven substrate can be made from pulp fibers alone or in combination with polymer synthetic fibers, such as polyester fibers. When producing nonwoven substrates for use in absorbent articles, the nonwoven substrate can contain superabsorbent particles combined with at least one type of fiber The at least one type of fiber can comprise pulp fibers, pulp fibers combined with polymer synthetic fibers, pulp fibers combined with binder fibers, pulp fibers combined with synthetic polymer fibers and binder fibers, pulp fibers combined with regenerated cellulose fibers, or any other suitable mixtures.

A wide variety of cellulosic fibers are believed suitable for use herein. In some embodiments, the fibers utilized can be conventional papermaking fibers such as wood pulp fibers formed by a variety of pulping processes, such as kraft pulp, sulfite pulp, bleached chemithermomechanical pulp (BCTMP), chemithermomechanical pulp (CTMP), pressure/pressure thermomechanical pulp (PTMP), thermomechanical pulp (TMP), thermomechanical chemical pulp (TMCP), and so forth. By way of example only, fibers and methods of making wood pulp fibers are disclosed in US4793898 to Laamanen et al.; US4594130 to Chang et al.; US3585104 to Kleinhart; US5595628 to Gordon et al.; US5522967 to Shet; and so forth. Further, the fibers may be any high-average fiber length wood pulp, low-average fiber length wood pulp, or mixtures of the same. Examples of suitable high-average length pulp fibers include softwood fibers, such as, but not limited to, northern softwood, southern softwood, redwood, red cedar, hemlock, pine (e.g., southern pines), spruce (e.g., black spruce), and the like. Examples of suitable low-average length pulp fibers include hardwood fibers, such as, but not limited to, eucalyptus, maple, birch, aspen, and the like.

In one aspect, chemically cross-linked cellulose fibers may be present. Chemically crosslinked cellulose fibers refer to any cellulosic fibrous material reacted with a cross-linking agent, the cross-linked cellulosic fibers may comprise cross-linked-eucalyptus hardwood kraft pulp fibers or softwood fibers. In certain embodiments, the cross-linking agent may comprise a urea-based crosslinking agent. Suitable urea-based cross-linking agents include substituted ureas such as methylolated ureas, methylolated cyclic ureas, methylolated lower alkyl cyclic ureas, methylolated dihydroxy cyclic ureas, dihydroxy cyclic ureas, and lower alkyl substituted cyclic ureas. Specific urea-based crosslinking agents include dimethyldihydroxy urea (DMDHU, 1 ,3-dimethyl-4,5-dihydroxy-2- imidazolidinone), dimethylol dihydroxy ethylene urea (DMDHEU, 1 ,3-dihydroxymethyl-4,5-dihydroxy-2- imidazolidinone), dimethylol urea (DMU, bis[N-hydroxymethyl]urea), dihydroxyethylene urea (DHEU, 4,5-dihydroxy-2 imidazolidinone), dimethylolethylene urea (DMEU, 1 ,3-dihydroxymethyl-2- imidazolidinone), and dimethyldihydroxyethylene urea (DMeDHEU or DDI, 4,5-dihydroxy-1 ,3-dimethyl- 2-imidazolidinone). A particularly preferred urea is dimethyldihydroxy urea (DMDHU, 1 ,3-dimethyl-4,5- dihydroxy-2 imidazolidinone. Suitable methods of preparing cross-linked fibers include those disclosed in U.S. Pat. No. 5,399,240, the contents of which are incorporated by reference.

Moreover, if desired, secondary fibers obtained from recycled materials may be used, such as fiber pulp from sources such as, for example, newsprint, reclaimed paperboard, and office waste. In a particularly preferred embodiment refined fibers are utilized in the tissue web such that the total amount of virgin and/or high average fiber length wood fibers, such as softwood fibers, may be reduced.

Regardless of the origin of the wood pulp fiber, the wood pulp fibers preferably have an average fiber length greater than about 0.2 mm and less than about 3 mm, such as from about 0.35 mm and about 2.5 mm, or between about 0.5 mm to about 2 mm or even between about 0.7 mm and about 1.5 mm.

In addition, other cellulosic fibers that can be used in the present disclosure includes nonwoody fibers. As used herein, the term “non-wood fiber” generally refers to cellulosic fibers derived from non-woody monocotyledonous or dicotyledonous plant stems. Non-limiting examples of dicotyledonous plants that may be used to yield non-wood fiber include kenaf, jute, flax, ramie and hemp. Non-limiting examples of monocotyledonous plants that may be used to yield non-wood fiber include cereal straws (wheat, rye, barley, oat, etc.), stalks (corn, cotton, sorghum, Hesperaloe funifera, etc.), canes (bamboo, sisal, bagasse, etc.) and grasses (miscanthus. esparto, lemon, sabai, switchgrass, etc). In still other certain instances non-wood fiber may be derived from aquatic plants such as water hyacinth, microalgae such as Spirulina, and macroalgae seaweeds such as red or brown algae.

Still further, other cellulosic fibers for making substrates herein can include synthetic cellulose fiber types formed by spinning, including rayon in all its varieties, and other fibers derived from viscose or chemically-modified cellulose such as, for example, those available under the trade names LYOCELL and TENCEL.

In some embodiments, the non-woody and synthetic cellulosic fibers can have fiber length greater than about 0.2 mm including, for example, having an average fiber size between about 0.5 mm and about 30 mm or between about 0.75 and about 8 mm or even between about 1 mm and about 5 mm. Cellulosic fibers, such as pulp fibers, can be present in the nonwoven substrate generally in an amount from about 5% by weight to about 60% by weight, including all increments of 1% by weight therebetween.

Additional fibers that may be utilized in the present disclosure include synthetic polymer fibers. By way of non-limiting example, such fibers comprised of polyolefin, polyester (PET), polyamide, polylactic acid, or other fiber forming polymers. Polyolefin fibers, such as polyethylene (PE) and polypropylene (PP), are particularly well suited for use in the present disclosure.

The synthetic polymer fibers can have fiber length greater than about 0.2 mm including, for example, having an average fiber size between about 0.5 mm and about 50 mm or between about 0.75 and about 15 mm or between about 1 mm and about 12 mm. In one embodiment, the synthetic polymer fibers can be staple fibers having a fiber length of greater than about 2 mm, such as greater than about 3 mm, such as greater than about 4 mm, and generally less than about 8 mm, such as less than about 7 mm, such as less than about 6 mm, such as less than about 5 mm, such as less than about 4 mm. The polymer fibers can have a size of less than about 5 denier, such as less than about 3 denier, such as less than about 2 denier, and greater than about 0.5 denier, such as greater than about 1 denier.

When present in the nonwoven substrate, synthetic polymer fibers can be contained in the substrate in an amount generally from about 3% by weight to about 80% by weight, including all increments of 1% by weight therebetween.

In one embodiment, the fiber furnish can include a binder material that consolidates the substrate once activated. For instance, the fiber furnish can include binder fibers that bond to adjacent fibers when heated, such as during the drying of the substrate.

Binder materials that may be used in the present disclosure can include, but are not limited to, thermoplastic binder fibers, such as PET/PE bicomponent binder fiber, and water-compatible adhesives such as, for example, latexes. In some embodiments, binder materials as used herein can be in powder form, for example, such as thermoplastic PE powder. Importantly, the binder can comprise one that is water insoluble on the dried substrate. In certain embodiments, latexes used in the present disclosure can be cationic or anionic to facilitate application to and adherence to cellulosic fibers that can be used herein. For instance, latexes believed suitable for use include, but are not limited to, anionic styrene-butadiene copolymers, polyvinyl acetate homopolymers, vinyl-acetate ethylene copolymers, vinyl-acetate acrylic copolymers, ethylene-vinyl chloride copolymers, ethylenevinyl chloride-vinyl acetate terpolymers, acrylic polyvinyl chloride polymers, acrylic polymers, nitrile polymers, as well as other suitable anionic latex polymers known in the art. Examples of such latexes are described in US4785030 to Hager, US6462159 to Hamada, US6752905 to Chuang et al. and so forth. Examples of suitable thermoplastic binder fibers include, but are not limited to, monocomponent and multi-component fibers having at least one relatively low melting thermoplastic polymer such as polyethylene. In certain embodiments, polyethylene/polypropylene sheath/core staple fibers can be used. Binder fibers may have lengths in line with those described herein above in relation to the synthetic polymer fibers.

Binders in liquid form, such as latex emulsions, can comprise between about 0% and about 10% (by weight) of the substrate. Binder fibers, when used, may be added proportionally to the other components to achieve the desired fiber ratios and structure. As an example, in some embodiments, binder fibers can comprise between about 0% and about 50% of the total fiber weight, and more preferably, between about 5% to about 40% of the total fiber weight in some embodiments.

One additional additive that can be added during the formation of the substrates 12 as described herein can be a superabsorbent materials (SAM). SAM is commonly provided in a particulate form and, in certain aspects, can comprise polymers of unsaturated carboxylic acids or derivatives thereof. These polymers are often rendered water insoluble, but water swellable, by crosslinking the polymer with a di- or polyfunctional internal crosslinking agent. These internally crosslinked polymers are at least partially neutralized and commonly contain pendant anionic carboxyl groups on the polymer backbone that enable the polymer to absorb aqueous fluids, such as body fluids. Typically, the SAM particles are subjected to a post-treatment to crosslink the pendant anionic carboxyl groups on the surface of the particle. SAMs are manufactured by known polymerization techniques, desirably by polymerization in aqueous solution by gel polymerization. The products of this polymerization process are aqueous polymer gels, i.e, SAM hydrogels that are reduced in size to small particles by mechanical forces, then dried using drying procedures and apparatus known in the art. The drying process is followed by pulverization of the resulting SAM particles to the desired particle size. Examples of superabsorbent materials include, but are not limited to, those described in US7396584 Azad et al., US7935860 Dodge et al, US2005/5245393 to Azad et al, US2014/09606 to Bergam et al, W02008/027488 to Chang et al. and so forth. In addition, in order to aid processing, the SAM may be treated in order to render the material temporarily non-absorbing during the formation of the foam and formation of the highly-expanded foam. For example, in one aspect, the SAM may be treated with a water-soluble protective coating having a rate of dissolution selected such that the SAM is not substantially exposed to the aqueous carrier until the highly-expanded foam has been formed and drying operations initiated. Alternatively, in order to prevent or limit premature expansion during processing, the SAM may be introduced into the process at low temperatures.

Superabsorbent materials can be incorporated into the nonwoven substrates generally in an amount from about 1% to about 90% by weight, including all increments of 1% by weight therebetween. For instance, the superabsorbent material can be present in the substrate in an amount greater than about 10% by weight, such as in an amount greater than about 30% by weight, such as in an amount greater than about 50% by weight, such as in an amount greater than about 70% by weight, such as in an amount greater than about 80% by weight, and generally in an amount less than about 90% by weight, such as in an amount less than about 85% by weight, such as in an amount less than about 80% by weight.

In one aspect, the nonwoven substrate made according to the present disclosure can be a multi-layer substrate. The superabsorbent material can be contained exclusively within a middle layer of the substrate. In this manner, the superabsorbent material is encapsulated within the nonwoven substrate. In addition, in this embodiment, the superabsorbent material preferentially resides in the high basis weight areas. Thus, if the nonwoven substrate is slit into strips, little to no superabsorbent material escapes.

Other additives that can be incorporated into the nonwoven substrates include wet strength additives, permanent wet strength additives, temporary wet strength additives, dry strength additives, and the like.

Still other additional components that may be added to the substrates include one or more pigments, opacifying agents, anti-microbial agents, pH modifiers, skin benefit agents, odor absorbing agents, fragrances, thermally expandable microspheres, foam particles (such as, pulverized foam particles), and so forth as desired to impart or improve one or more physical or aesthetic attributes. In certain embodiments, the substrates may include skin benefit agents such as, for example, antioxidants, astringents, conditioners, emollients, deodorants, external analgesics, film formers, humectants, hydrotropes, pH modifiers, surface modifiers, skin protectants, and so forth.

When employed, miscellaneous components desirably comprise less than about 2% of the substrate (by weight).

The present disclosure may be better understood with reference to the following examples.

Examples

The following examples were produced in accordance with the present disclosure. The examples were produced according to a wet-lay process. As described above, however, in other embodiments, substrates can be made according to a foam forming process.

Example No. 1

A nonwoven substrate was formed on a forming surface including high porosity zones and low porosity zones. The forming surface was made from a woven fabric. Parallel resin stripes were printed onto the top surface of the fabric to form the low porosity zones. The resin produced raised areas on the fabric. In particular, the stripes were 1 .5 mm tall and 3 mm wide, with a half ellipse crosssection. An aqueous suspension of fibers was produced containing 17.5 g of superabsorbent particles, 1 .19 g of northern softwood kraft fibers, 0.71 g of bicomponent binder fibers, and 0.47 g of polyester fibers. The bicomponent fibers had a size of 2.2 dTex and had a length of 6 mm. The bicomponent fibers included a core made from a high temperature polyester and a sheath made from a low temperature polyethylene. The polyester fibers had a size of 6.7 dTex and also had an average fiber length of 6 mm.

The aqueous suspension of fibers was deposited onto the forming surface and a nonwoven substrate was formed. In particular, the above fibers and superabsorbent particles were added to 4 liters of water, stirred, and quickly deposited onto the forming surface. The wet nonwoven substrate was dried and cured to bond the binder fibers at 134°C. The resulting nonwoven substrate included low basis weight areas and high basis weight areas corresponding to the pattern of high porosity zones and low porosity zones on the forming surface. The nonwoven substrate was continuous and did not contain any holes.

Example No. 2

In this example, the forming surface described in Example No. 1 was turned upside down and used to produce a nonwoven substrate. Thus, the forming surface was planar and did not include any raised areas. The same procedure was used to produce the nonwoven substrate. The resulting nonwoven material had high basis weight areas and low basis weight areas corresponding to the high porosity zones and low porosity zones on the forming surface. The nonwoven substrate produced was continuous indicating that raised areas were not necessary to produce the high and low basis weight substrates.

Example No. 3

In this example, a forming surface was made from a woven fabric. Three-dimensional printing was used to apply 4 mm wide columns onto the forming surface. The additive material was impregnated into the fabric in order to produce low porosity zones that were not raised from the surface of the fabric.

The same fiber furnish and process as described in Example No. 1 was used to produce a wet-laid nonwoven substrate. The resulting nonwoven substrate had low basis weight fluid control channels surrounded by high basis weight areas. The nonwoven substrate was continuous. The high basis weight areas had a basis weight of 600 gsm and the low basis weight areas had a basis weight of 160 gsm. Consequently, the low basis weight areas represented a decrease in basis weight of over 70%.

Example No. 4

In this example, a forming surface was produced made from a woven fabric. The fabric included pores having a diameter of 0.42 mm. An additive material using three-dimensional printing was applied to the surface of the fabric. In particular, two 6 mm wide elongated columns were applied to the fabric that created raised areas on the fabric having a height of 2 mm. The cross-sectional shape of the column represented a half ellipse. Two other 6 mm columns were also applied to the surface of the fabric but were formed by the three-dimensional printer such that the additive material impregnated the fabric without creating any raised features. All four elongated columns contained no pores and thus had a zero porosity.

The process described in Example No. 1 and the same fiber furnish was used to produce a nonwoven substrate The resulting nonwoven substrate had voids or holes corresponding to the location of the non-porous columns. Thus, the sheet produced was discontinuous.

Example No. 5

In this example, a forming surface was created from a woven fabric. An additive material was applied to the surface of the fabric using three-dimensional printing. The additive material was impregnated into the fabric to form 8 mm wide columns. The columns did not create raised areas on the fabric. Each column included a continuous matrix of the additive material. The three-dimensional printing, however, was used to produce small openings of roughly 1 mm x 1 mm in a staggered pattern within the column. The total open area of the columns was about 3%.

The fiber furnish and process described in Example No. 1 was used to produce a nonwoven substrate. The resulting nonwoven substrate had low basis weight, fluid control canals corresponding to the location of the printed columns. Due to the porosity of the printed columns, the low basis weight areas contained fibers and superabsorbent particles to form a continuous sheet. The low basis weight areas had a thickness of 0.5 mm. The difference in thickness between the high basis weight areas and the low basis weight areas was 4.1 mm. The difference in basis weight was substantially equal to the difference in thickness.

Example No. 6

In this example, a forming surface was created from a woven fabric. An additive material was applied to the surface for forming high porous zones and low porous zones. The forming surface was similar to the forming surface illustrated in FIG. 9. The low porosity zones had a width of about 12 mm and the high porosity zones had a width of about 84 mm.

A foam forming continuous process pilot line was used to produce a nonwoven substrate similar to the process illustrated in Figures 1 and 2. The nonwoven substrate was similar in appearance to the nonwoven substrate illustrated in FIG. 10. In this embodiment, a multi-layer substrate was produced in which a superabsorbent material was contained within a middle layer positioned between a top fibrous layer and a bottom fibrous layer. All documents cited in the Detailed Description are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention. To the extent that any meaning or definition of a term in this written document conflicts with any meaning or definition of the term in a document incorporated by references, the meaning or definition assigned to the term in this written document shall govern.

These and other modifications and variations to the present invention may be practiced by those of ordinary skill in the art, without departing from the spirit and scope of the present invention, which is more particularly set forth in the appended claims. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention so further described in such appended claims.

Claims

What is Claimed:

1 . A process for forming nonwoven substrates comprising: depositing a wet suspension of fibers onto a forming surface, the suspension of fibers including at least a first type of fiber having an average fiber length, the forming surface including a pattern of porous first zones and porous second zones, the first zones having a porosity greater than a porosity of the second zones, the porosity of the second zones being at least 50% less than the porosity of the first zones; and draining fluids from the forming surface causing a nonwoven substrate to form having high basis weight areas corresponding to the first zones and low basis weight areas corresponding to the second zones.

2. A process as defined in claim 1 , wherein the porosity of the second zones is at least 80% less, such as at least 90% less, such as at least about 95% less, than the porosity of the first zones.

3. A process as defined in any of the preceding claims, wherein the second zones have a porosity such that the second zones have from about 0.5% to about 20% open area, such as from about 1% to about 10% open area.

4. A process as defined in any of the preceding claims, wherein the suspension of fibers contains a plurality of different types of fibers and the second zones have a width dimension that is greater in distance that the average fiber length of the fiber type with the longest fibers in the suspension of fibers.

5. A process as defined in any of the preceding claims, wherein the suspension of fibers contains superabsorbent particles.

6. A process as defined in any of the preceding claims, wherein the width dimension of the second zones is greater than about 4 mm, such as greater than about 5 mm, such as greater than about 6 mm, such as greater than about 7 mm, and less than about 10 mm.

7. A process as defined in any of the preceding claims, wherein the second zones form columns on the forming surface.

8. A process as defined in claim 7, wherein the columns are linear and parallel.

9. A process as defined in claim 7 or 8, wherein the columns have a width dimension of from about 4 mm to about 10 mm and the columns are spaced apart a distance of from about 6 mm to about 20 mm.

10. A process as defined in any of the preceding claims, wherein the nonwoven substrate is wound into a roll.

11. A process as defined in any of the preceding claims, further comprising the step of slitting the nonwoven substrate along the second zones.

12. A process as defined in any of the preceding claims, wherein the low basis weight areas have a basis weight that is greater than about 50%, such as greater than about 70% less than a basis weight of the high basis weight areas.

13. A process as defined in any of the preceding claims, wherein the low basis weight areas have a thickness that is greater than about 50%, such as greater than about 70% less than a thickness of the high basis weight areas.

14. A process as defined in any of the preceding claims, wherein the forming surface is planar and does not include raised areas on a top surface.

15. A process as defined in any of the preceding claims, wherein the forming surface comprises a fabric formed from woven yarns, the second zones comprising zones where an additive material has been applied to the fabric.

16. A process as defined in any of the preceding claims, wherein the wet suspension of fibers comprises a blend of synthetic polymer fibers, pulp fibers, superabsorbent particles, or mixtures thereof.

17. A process as defined in any of the preceding claims, wherein the wet suspension of fibers comprises polymer synthetic fibers.

18. A process as defined in any of the preceding claims, wherein the wet suspension of fibers comprises a foamed suspension of fibers to produce a foam formed substrate.

19. A process as defined in any of the preceding claims, wherein the foamed suspension of fibers is formed by combining a foam with a fiber furnish, the foam having a density of from about 200 g/L to about 600 g/L, such as from about 250 g/L to about 400 g/L.

20. A process as defined in any of the preceding claims, wherein the foamed suspension is formed by combining a foaming agent with water, the foamed suspension of fibers containing from about 40% to about 80% by volume air.

21 . A process as defined in claim 1 , wherein the dried nonwoven substrate has an average basis weight of from about 20 gsm to about 800 gsm, such as from about 30 gsm to about 200 gsm.

22. A process as defined in any of the preceding claims, wherein the nonwoven substrate is continuous.

23. A nonwoven material as defined in any of the preceding claims, wherein the nonwoven material contains pulp fibers.

24. A forming sheet for producing nonwoven substrates comprising: a forming wire comprising a fabric formed from woven yarns, the fabric including a top, forming surface including a pattern of porous first zones and porous second zones, the first zones having a porosity greater than a porosity of the second zones, the porosity of the second zones being at least 50% less than the porosity of the first zones, the second zones having a width dimension that is greater than about 4mm.

25. A forming sheet as defined in claim 24, wherein the second zones comprise zones where an additive material has been applied to the fabric.

26. A forming sheet as defined in claim 24 or 25, wherein the second zones comprise parallel columns.

27. A forming sheet as defined in claim 24 or 25, wherein the second zones form a gridlike pattern.

28. A forming sheet as defined in claim 26, wherein the columns have a wavy shape.

29. A nonwoven substrate comprising: a continuous, nonwoven web having a first surface and a second and opposite surface, the nonwoven web comprising synthetic polymer fibers; the nonwoven web having an average basis weight of from about 30 gsm to about 800 gsm; and wherein the nonwoven web includes a pattern of high basis weight areas and low basis weight areas, wherein the low basis weight areas have a basis weight that is at least about 50% less than a basis weight of the high basis weight areas.

30. A nonwoven substrate as defined in claim 29, wherein the nonwoven substrate further contains binder fibers.

31 . A nonwoven substrate as defined in claim 29, wherein the nonwoven substrate further contains pulp fibers.

32. A nonwoven substrate as defined in claim 29, wherein the nonwoven substrate further contains a superabsorbent material, the superabsorbent material being present in the nonwoven substrate in an amount from about 10% by weight to about 90% by weight.

33. A nonwoven substrate as defined in claim 32, wherein the nonwoven substrate includes a top layer, a middle layer, and a bottom layer, and wherein all of the superabsorbent material is contained in the middle layer.

34. A nonwoven substrate as defined in any of claims 29-33, wherein the low basis weight areas have a thickness that is at least about 50% less than a thickness of the high basis weight areas.

35. A nonwoven substrate as defined in any of claims 29-34, wherein the low basis weight areas have a density that is at least about 50% less than a density of the high basis weight areas.

36. A nonwoven substrate as defined in any of claims 29-35, wherein the nonwoven substrate further comprises crosslinked pulp fibers.

37. A nonwoven substrate as defined in any of claims 29-36, wherein the nonwoven substrate has a basis weight of greater than about 100 gsm, such as greater than about 150 gsm, and less than about 800 gsm.

38. A nonwoven substrate as defined in claim 30, wherein the binder fibers are present in an amount from about 5% by weight to about 40% by weight.

39. A nonwoven substrate as defined in any of claims 29-38, wherein the synthetic polymer fibers are present in the nonwoven substrate in an amount from about 3% by weight to about 35% by weight.

40. An absorbent article comprising: a fluid permeable liner; an outer cover; and an absorbent core positioned between the liner and the outer cover, the absorbent core comprising the nonwoven substrate of claim 29.