RU2778235C1 - Method for manufacturing three-dimensional nonwovens obtained by molding foam material - Google Patents

Abstract

FIELD: material processing.

SUBSTANCE: group of inventions relates to methods for manufacturing a nonwoven substrate with high topography in the field of absorbent products. The method includes the creation of foam containing water and synthetic binding fibers, the application of foam material on a flat surface, the placement of a template mold on the foam material opposite to the flat surface with the creation of foam material/mold assembly. Then the foam material/mold assembly is heated to dry the foam material and bind synthetic binding fibers, and then the template is removed from the substrate. In this case, the substrate contains a flat base layer having an X-Y surface and a surface on the reverse side opposite to the X-Y surface, and a set of protruding elements made as one with the X-Y surface and protruding from it in the Z direction, while each protruding element has a near end on which the protruding element it comes into contact with the base layer, while the density of the protruding element is equal to the density of the base layer, and the side walls have more than 50 percent of the fibers oriented in the Z direction.

EFFECT: improvement in the absorbent properties of the products.

19 cl, 6 dwg, 1 tbl

Description

BACKGROUND OF THE INVENTION

Leakage of liquid stool (BM) from a diaper (ie, seepage around the leg area or at the waist) causes nuisance soiling that needs to be cleaned up by the caregiver. The consumer/choice maker remains dissatisfied with the chosen absorbent product, which may lead to the consumer/choice maker making a decision to switch to a different diaper brand. Approximately one in seven diapers containing VM results in oozing of VM from the diaper. In addition, VMs in contact with the skin can endanger skin health and cause diaper rash. Skin without a diaper may be healthier than skin in a diaper because modern diapers don't do enough work to keep the BM away from the skin.

There is a lack of material/nonwoven solutions to reduce the incidence of IM bleed and to keep the VM away from the skin. Current materials in absorbent products, such as spunbond, SMS, and BCW, are typically flat, dense, and do a poor job of handling flowable VMs and keeping VMs away from the skin. There are materials such as perforated films and BCW/SB textured composite nonwovens (such as TEXTOR branded nonwovens) that are used as interlining materials. TEXTOR branded nonwovens can improve VM handling properties over spunbond liner and are used in today's products. However, too many modern products containing HM lead to BM seepage. As a result, there is an excellent opportunity to identify materials that improve the effectiveness of the management of HMW absorbent products.

SUMMARY OF THE INVENTION

The materials of the present invention represent the next step in providing a diaper that fully absorbs fluid WM at the interface, does not leave any bleed of WM and WM on the skin, and provides zero bleed-through of WM and a cleaner skin impression. The identification of solutions to reduce VM breakouts and the presence of VM on the skin is beneficial both for the user of the product and because of the possible better consumer experience of such products by reducing the incidence of diaper rash and providing a point of differentiation with respect to other products.

The solutions described herein are nonwovens having high degrees of three-dimensional (3D) topography and high compressive strength, while at the same time having a high level of porosity. Such materials have shown significantly better HM absorption compared to current commercially available materials used in current products. The plate BM absorption test method has demonstrated that the three-dimensional foam-molded webs of the present invention reduce BM accumulation by up to 2 wt. %, while for non-woven materials of the TEXTOR trademark it is 40 wt. %. The BM accumulation values are similar to the rewet values and represent the amount of BM on the skin.

The present invention describes novel nonwovens with a high degree of three-dimensionality having improved HMW handling properties. These materials can improve absorbent products by reducing the shedding of BM and the amount of BM on the skin. These nonwoven structures are made possible by stenciling the foam molded webs, otherwise referred to as three-dimensional foam molded nonwoven fabrics. The method includes dispersing the bicomponent fibers in a foam and stenciling the foam during drying and thermal bonding. This method results in non-woven webs with a high degree of three-dimensionality, containing elements up to 12 mm high and up to 8 mm in diameter. Due to these three-dimensional elements, there is a high level of fiber orientation in the z-direction, resulting in webs that have high compressive strength and at the same time a high level of openness/porosity, which are key properties for the processability of fluid VMs. In addition, depending on the design of the template, a wide variety of three-dimensional features, shapes and sizes can be obtained.

The present invention is generally directed to a method for making a high topography nonwoven substrate, the method comprising providing a foam containing water and synthetic binder fibers; applying foam to a flat surface; placing the template mold on the foam opposite a flat surface to create a foam/mould assembly; heating the foam/mould assembly to dry the foam and bind the synthetic binder fibers; and removing the pattern from the substrate after heating the foam/mould assembly, wherein the substrate comprises a flat base layer having an X-Y surface and a surface on the reverse side opposite the X-Y surface; and a plurality of protruding elements integral with the X-Y surface and protruding from it in the Z direction, with each protruding element having a height, diameter or width, a cross section, a side wall, a proximal end at which the protruding element comes into contact with the base layer, and the far end opposite the proximal end, while the protruding elements are distributed in both directions X and Y, and the density of the protruding element is equal to the density of the base layer.

In another aspect, the present invention is directed generally to a method for making a high topography nonwoven substrate, the method comprising: providing a foam containing water and synthetic binder fibers; applying foam to a flat surface; placing the template mold on the foam opposite a flat surface to create a foam/mould assembly; heating the foam/mould assembly to dry the foam and bind the synthetic binder fibers; and removing the template from the substrate after heating the foam/mould assembly, wherein the substrate contains synthetic binder fibers, wherein the fibers of the substrate are fully synthetic binder fibers; a flat base layer having an X-Y surface and a surface on the reverse side opposite the X-Y surface; and a plurality of protruding elements integral with the X-Y surface and protruding from it in the Z direction, with each protruding element having a height, diameter or width, a cross section, a side wall, a proximal end at which the protruding element comes into contact with the base layer, and a distal end opposite the proximal end, wherein the protrusions are distributed in both X and Y directions, wherein the cross-sectional shape of the protrusion at the proximal end of the protrusion is the same as the cross-sectional shape of the protrusion at the distal end of the protrusion, and the density of the protruding element is equal to the density of the base layer.

In yet another aspect, the present invention is directed generally to a method for making a high topography nonwoven substrate, the method comprising providing a foam containing water and synthetic binder fibers; applying foam to a flat surface; placing the template mold on the foam opposite a flat surface to create a foam/mould assembly; heating the foam/mould assembly to dry the foam and bind the synthetic binder fibers; and removing the template from the substrate after heating the foam/mould assembly, wherein the substrate comprises synthetic binder fibers, wherein the substrate fibers are fully synthetic binder fibers, wherein the substrate comprises a flat base layer having an X-Y surface and a surface on the reverse side opposite X-Y surfaces; and a plurality of protruding elements integral with the X-Y surface and protruding from it in the Z direction, with each protruding element having a height, diameter or width, a cross section, a side wall, a proximal end at which the protruding element comes into contact with the base layer, and the distal end opposite the proximal end, wherein the protrusions are distributed in both X and Y directions, with each protrusion having a uniform density, wherein the height of the protrusion is greater than the width or diameter of that protrusion, and the density of the protrusion equal to the density of the base layer.

Various features and aspects of the present invention will become more apparent from the following detailed description.

BRIEF DESCRIPTION OF GRAPHICS

A complete and sufficient description of the present invention, including the best mode for its implementation for a person skilled in the art, is set forth below, in particular in the description, including reference to the relevant figures, in which:

in fig. 1 is a flow chart of one exemplary aspect of a process for producing three-dimensional foam-molded nonwovens according to the present invention;

in fig. 2 is a schematic perspective view of one aspect of a template for use in the method of FIG. one;

in fig. 3 is a photographic representation of the results of a leak test on various nonwoven materials, including materials obtained using the method shown in FIG. one;

in fig. 4 is a graphical representation of the results of a leak test on various nonwoven fabrics, including those made using the method shown in FIG. one;

in fig. 5 is a graphical representation of the results of a compressive strength test of various nonwoven materials, including materials obtained using the method shown in FIG. one; and

in fig. 6 is a graphical representation of the breathability test results for various nonwoven fabrics, including those made using the method shown in FIG. one.

The reuse of reference numbers in the present description and drawings is intended to represent the same or similar features or elements according to the present invention.

DETAILED DESCRIPTION

Reference will now be made to aspects of the present invention, one or more examples of which are set forth below. Each example is provided to illustrate the present invention and not to limit it. Indeed, it will be apparent to those skilled in the art that various modifications and changes can be made to the present invention without departing from the scope or spirit of the present invention. For example, features illustrated or described as part of one aspect may be used in another aspect to form another aspect. Thus, the present invention is intended to cover such modifications and changes as fall within the scope of the appended claims and their equivalents. One skilled in the art will appreciate that the present discussion is a description of exemplary aspects only and is not intended to limit the broader aspects of the present invention that are embodied in the exemplary designs.

The present invention describes novel nonwovens with a high degree of three-dimensionality having improved HMW handling properties. These materials can improve absorbent products by reducing the shedding of BM and the amount of BM on the skin. These nonwoven structures are made possible by stenciling foam molded webs, otherwise referred to as three-dimensional foam molded webs. The method includes dispersing the bicomponent fibers in a foam and stenciling the foam during drying and thermal bonding. This method results in three-dimensional nonwoven webs with a high degree of three-dimensionality and with relatively high and narrow three-dimensional elements. Due to these three-dimensional elements, there is a high level of fiber orientation in the z-direction, resulting in webs that have high compressive strength and at the same time a high level of openness/porosity, which are key properties for the processability of fluid VMs. In addition, depending on the design of the template, a wide variety of three-dimensional features, shapes and sizes can be obtained.

Foam-based processes are typically used to produce flat webs having a uniform thickness, such as two-dimensionally shaped profiles. As described herein, a three-dimensional nonwoven web is created using a three-dimensional foam mold to form a three-dimensional topography. Drying and heating the patterned foam results in a nonwoven fabric having the topographic properties of the pattern.

Any additional shaping of the nonwoven web is excluded from the method of the present invention, since the necessary topography is created along with the creation of the nonwoven web itself. Prior methods for processing nonwovens require post-forming, cutting, embossing, or shaping of the existing nonwoven web, which results in web weakness along with wide variations in its density and basis weight.

The creation of the nonwoven structures described herein requires three main steps: 1) Dispersing the binder fibers and foaming agent in water to create a foaming solution with a consistency that can be described as creamy. 2) Stenciling the fiber/foam mixture. 3) Drying and heating the mixture to remove water and activate the binder fibers, and thus solidify the three-dimensional structure in the nonwoven material. Such webs are referred to herein as three-dimensional foam-spun nonwovens.

In the first step, the binder fiber and foaming agent are dispersed in water to create a foaming solution with a consistency that can be described as creamy. This step includes dispersing a mixture of fibers capable of forming interfiber bonds (eg, bicomponent fibers/bonding fibers) in a foaming solution. This step is carried out by simultaneously mixing fibers, water and a blowing agent such as sodium dodecyl sulfate (SDS) surfactant to create a foam and uniformly suspend the fibers in the foam. This foaming method creates a stable foam containing a fibrous network uniformly dispersed in the foaming solution. The foam has a high viscosity that prevents floating, settling and/or agglomeration of the fibers.

Many types of fibers can be included in the fiber blend, but the blend should contain sufficient binder fibers to ensure the integrity of the finished three-dimensional foam-spun nonwoven and its ability to retain three-dimensional structural elements. In one example, a mixture of fibers per 100 wt. % consists of binder fibers containing a polyethylene sheath and a polypropylene core. The binder fibers are typically synthetic thermoplastic binder fibers. In other aspects, the binder fibers may be bi- and/or multi-component binder fibers. In other aspects, the mixture of fibers may contain cellulosic fibers.

In another aspect of the present invention, a light, non-crimped bicomponent staple fiber is obtained using nanovoid technology with a reduction in fiber density of 20-33%. By using these lightweight fibers in a fiber blend, the number of fibers can be increased without changing the basis weight, thereby increasing the compressive strength of the web. In various aspects, the low density fiber may have a density of up to 0.5 grams/cubic centimeter or even less. In one example, low-density void fibers used may have a density of 0.62 g/cm ³ , which is equal to a polyolefin-based fiber with a 33% reduction in overall density and a core pore volume of 47%. Foaming is a preferred method of forming a nonwoven web containing low density fibers that provides high grade fibers using void fibers and does not require headbox crimped fibers. For example, carded webs require fibers crimped in the headbox to form the web. The crimping process in the headbox is a high pressure process that breaks the internal fiber void structure and is therefore unable to form a carded web containing low density void fibers. Due to the high viscosity of the foam, low density fibers are properly laid down in a web using the foam as a carrier, thus making it possible to form webs containing low density fibers.

While some level of binder fiber content is required, the fiber blend need not contain only binder fibers; other types of fibers may also be included in the mixture. The choice of fibers may include synthetic fibers of all types to a wide range of natural fibers. The fibers may comprise a wide range of cut lengths/fiber lengths, such as 3-30 mm. A wide range of diameters can also be used. A wide variety of blowing agents can be used, such as anionic and nonionic, in amounts in the range of 0.1-5 wt. %. Typically, SDS is used at a concentration of approximately 0.17 wt. % in relation to water. The density of the foam may be in the range of 100-400 g/l. The foam stability half-life can be in the range of 2-30 minutes. The fiber consistency (fiber concentration) can be in the range of 0.5-5 wt. %.

In the second step, the fiber/foam mixture is poured or applied to the perforated tape or other suitable surface in any suitable manner. The tape optionally includes a frame shape to limit the flow of the fiber/foam mixture on the tape. The template is then placed on top of the fiber/foam mixture, usually in a mold if present. The template provides a negative configuration for the desired configuration of the three-dimensional foam-molded nonwoven. In one illustrative example, if a convex surface is required for the nonwoven, the template will have a concave surface configuration. Once the template is placed, the fiber/foam mixture conforms to the topography of the template, essentially creating foam protrusions where the template contains dimples, dimples where the template contains protrusions, and flat surfaces where the template is flat. Thus, the template creates a three-dimensional topography in the foam.

Typically, the template contains cavities into which the fiber/foam mixture can flow to fill them. The dimensions of the cavities range from 8 mm or more in diameter, and the depths of the cavities can be as large as the thickness of the applied foam to 50 mm or more. In one example, the template cavities are 12 mm deep. The cavities may be any suitable shape, including round, rectangular, square, triangular, mushroom, symbol shape, toroidal, or more complex combinations of shapes, and the template cavities may contain any combination of shapes, sizes, and depths, or the template cavities may be uniformly shaped , size and depth, as long as the fiber/foam mixture can flow and fill the cavities in the template.

The template material should be chosen to withstand bonding temperatures. Examples of template materials include silicone, metal, polyurethane, polytetrafluoroethylene, and any other suitable material. The stencil material should also be chosen so that the fibers do not stick to the stencil, thus allowing easy separation of the web from the stencil or the template from the web after thermal activation of the binder fibers. In other words, the bonding fibers should preferentially adhere to other bonding fibers rather than to the template material. In general, fiber-to-template bonding problems are overcome by enhancing bonding between fibers. The template must also be sufficiently open to allow adequate airflow and heat transfer to allow drying and thermal activation of the binder fiber.

In a third step, the templated fiber/foam mixture is placed in an oven or other suitable heating device to dry and thermally bond the binder fibers. Importantly, to ensure the presence of a three-dimensional structure in the finished web, the template is also present during the drying/binding step. Temperatures and times in the oven must be high enough to remove sufficient water and sufficiently activate the binder fiber. The time and temperature can be set by one of skill in the art based on the ingredients in the fiber/foam blend, the volume and surface area of the fiber/foam blend, the specifications of the oven used, the initial condition of the patterned fiber/foam blend, and any other relevant conditions.

In the described method, unique canvases are obtained. By selecting different patterns (eg, patterns with different sizes, shapes, cavity depths, cavity spacings, etc.), different high topography three-dimensional nonwoven fabrics can be obtained. Three-dimensional nonwoven materials obtained by molding the foam using the method described in this document, usually contain a base layer that defines the X-Y surface and the surface on the reverse side opposite the X-Y surface.

Three-dimensional nonwoven fabrics obtained by foam molding also contain vertical (extending in the Z direction) elements, such as protruding elements protruding in the Z direction from the base layer and made in one piece with it. They are often referred to as a three-dimensional structure in the form of "peaks and troughs." Each protruding element has a height, diameter or width, a cross section, a side wall, a proximal end where the protruding element comes into contact with the base layer, and a distal end opposite the proximal end. The protrusions are typically distributed in both the X and Y directions. The protrusions may be evenly distributed in both the X and Y directions, or the configuration of the protrusions may change in either one or both directions.

Depending on the design of the template, you can create vertical elements of different shapes and sizes. For example, the horizontal cross section of the protruding member may be any suitable shape, including round, rectangular, square, triangular, mushroom, character, toroidal, or more complex combinations of shapes. The height of the vertical members can range from 1mm to 50mm or more, 1mm to 30mm, 5mm to 50mm, 5mm to 30mm, 30mm to 50mm, or any other height range. The width or diameter of the vertical element, depending on the shape of the cross section, can be 8 mm or more. The heights of the protruding elements are preferably greater than the width or diameter of the protruding elements. In various aspects, the ratio of the height of the protrusion to the width or diameter of the protrusion exceeds 0.5.

Due to the manner in which the three-dimensional foam molded material was obtained, the density of the projecting member is generally equal to or similar to that of the base layer. In various aspects, the cross-sectional shape of the protrusion at the proximal end of the protrusion is the same as the cross-sectional shape of the protrusion at the distal end of the protrusion. Alternatively, the cross-sectional shape of the protrusion at the proximal end of the protrusion may be different from the cross-sectional shape of the protrusion at the distal end of the protrusion. The density of the protrusion at the proximal end of the protrusion may be equal to or different from the density of the protrusion at the distal end of the protrusion. The basis weight of the protrusion at the proximal end of the protrusion may be equal to or different from the density of the protrusion at the distal end of the protrusion. In other aspects, the cross-sectional dimension of the protrusion at the proximal end of the protrusion may be equal to or different from the cross-sectional dimension of the protrusion at the distal end of the protrusion.

Each protruding element may have an internally uniform density. In other words, each protrusion typically has a uniform density and is substantially free of hollow or compacted portions. The protruding elements may have a density of 0.001 to 0.02 g/cm ³ . Three-dimensional foam-spun nonwovens exhibit a basis weight range of 15 g/m ² to 120 g/m ² , although lower or higher basis weights can be obtained using the method described herein.

Due to the manner in which the three-dimensional foam molding material was produced, the projections, and in particular the sidewalls of the projections, contain fibers aligned in the Z direction. In some aspects, the sidewalls have more than 50 percent of the fibers oriented in the Z direction. With a high degree of fiber orientation in the Z direction, the three-dimensional foam-spun nonwovens described herein exhibit very high compressive strength and at the same time are very open and have a high level of porosity. By comparison, a "flat" bonded carded (BCW) surge absorber provides a compression strength of approximately 25 ^cc /g at a pressure of 0.6 kPa. Three-dimensional nonwoven materials obtained by molding the foam according to the present invention provide a compression resistance of approximately 35-65 cm ³ /g under a pressure of 0.6 kPa. In addition, such a high level of compressive strength can only be achieved with very porous web structures. Also for comparison, an MGL9 liquid surge absorber with a basis weight of 100 g/m ² , a standard liquid surge absorbent material, type BCW, has an air permeability value of approximately 440 ft ³ /min, while foam molded 3D nonwoven fabrics have this value in range 1000-2500 ft ³ /min.

Factory testing of 3D foam molded nonwovens has demonstrated improved VM handling properties. For example, the HMW flow rate test method measures the amount of HMW simulant transferred from the HMW-reactive nonwoven to the blotting paper. A liner made from TEXTOR branded nonwoven typically results in approximately 40% of the BM simulant remaining on the surface of the liner as shown using blotting paper (i.e. the remaining amount is also referred to as % buildup). Three-dimensional foam-spun nonwovens of the present invention exhibited approximately half the % buildup (i.e., 20%) of TEXTOR branded nonwovens at about half the basis weight of TEXTOR branded nonwovens (55 g/ ^m2 for TEXTOR brand nonwovens compared to 30 g/ ^m2 for foam-spun nonwovens). At higher basis weights, such as at 60 g/m ² , foam-spun nonwovens exhibited less than 2% accumulation of HMW simulant. The % accumulation indicator can be considered similar to "what's on the skin" or rewet values.

EXAMPLES

Techniques

Air permeability test

Air permeability was measured in cubic feet of air per minute passing through an area of 38 square centimeters (7 cm diameter circle) using a Textest FX3300 air permeability test machine manufactured by Textest Ltd., Zurich, Switzerland. All tests were carried out in the laboratory at 23 ± 2°C and 50 ± 5% relative humidity. Specifically, prior to laboratory testing, the nonwoven sheet was allowed to dry and condition for at least 12 hours at 23 ± 2°C and 50 ± 5% relative humidity. A sheet of nonwoven fabric was clamped in a test hole for sheets with a diameter of 7 cm, and the test apparatus was set to a pressure drop of 125 Pa. Wrinkles and folds over the fabric test hole should be avoided when placing as much as possible. The setup was turned on by applying a clamping force to the sample. To achieve a steady state, the air flow at a pressure drop of 125 Pa was recorded after 15 seconds of air flow.

The air permeability test measured the airflow rate through a known area of the dry sample. The air permeability of each sample was measured using a Textest FX3300 air permeability test rig from Schmid Corporation of Spartanburg, South Carolina.

A sample from each test piece was cut and positioned such that the sample was outside the clamp area of the air permeability test rig. The test samples were obtained from areas of the sample that did not have wrinkles, compression lines, perforations, wrinkles and/or any distortion that distinguishes them from the rest of the test material.

The tests were carried out in a standard laboratory atmosphere at 23 ± 1°C (73.4 ± 1.8°F) and 50 ± 2% relative humidity. Before testing any samples, the instrument was turned on and allowed to warm up for at least 5 minutes. Prior to analysis of the test material, the instrument was calibrated according to the manufacturer's instructions. The instrument's pressure sensors were set to zero by pressing the NULL RESET button on the instrument. Before testing and, if necessary, between samples or samples, the dust filter was cleaned according to the manufacturer's instructions. The following specifications were chosen for data collection: (a) unit of measurement: cubic feet per minute (ft ³ /min); (b) test pressure: 125 Pascals (0.5 inches or 12.7 mm of water column); and (c) test head: 38 square centimeters (cm ² ). Since test results obtained with test heads of different sizes are not always comparable, specimens to be compared should be tested with test heads of the same size.

The NULL RESET button was pressed before each series of tests, or when the instrument's red light came on. Before pressing the NULL RESET button, the test head was opened (no sample in place) and the vacuum pump was completely stopped.

Each sample was placed on the lower test head of the instrument. The test was started by manually pressing the clamping lever until the vacuum pump was automatically started. The range indicator light on the instrument was set to the green or yellow area using the RANGE knob. After stabilization of the digital display, the air permeability of the sample was displayed and its value was recorded. The test procedure was repeated for 10 samples of each sample, and the average value for each sample was recorded as air permeability.

Compression test method

A 38 mm x 25 mm test specimen was cut from the target nonwoven fabric. Stainless steel top and bottom plates were attached to a dynamometer (Model: Alliance RT/1, manufactured by MTS System Corporation, based in Eden Prairie, Minnesota, USA). The top plate had a diameter of 57mm while the bottom plate had a diameter of 89mm. The top plate was connected to a 100 N load cell, while the bottom plate was connected to the base of the dynamometer. TestWorks Version 4 software provided by MTS was used to control the displacement of the top plate and record the load and distance between the two plates. The top plate was initiated to slowly move down and touch the bottom plate until the compressive load reached about 5000 g. At this point, the distance between the two plates was zero. The top plate was then set to move upwards (away from the bottom plate) until the distance between the two plates reached 15 mm. The slider readings shown on the TestWorks Version 4 software were set to zero. The test piece was placed in the center of the bottom plate with the projections facing the top plate. The top plate was initiated to descend towards the bottom plate and compress the test specimen at a rate of 25 mm/min. The distance traveled by the top plate was indicated by reading the slider. It was a loading process. Upon reaching a force of 345 grams (approximately 3.5 kPa), the top plate stopped its downward movement and returned at a speed of 25 mm/min to its original position, in which the distance between the two plates was 15 mm. It was a process of unloading. The compressive load and the corresponding distance between two plates under load and unload was recorded on a computer using the TestWorks Version 4 software provided by MTS. The compressive load was converted to compressive stress by dividing the compressive force by the area of the test piece. The distance between two plates at a given compressive stress is the thickness at that particular compressive stress. In order to obtain representative load and release curves for each test piece code, a total of three test pieces were tested for each test piece code.

Leak test method

The leak test was performed using the simulant A, which was applied to the target nonwoven fabric. The HMW simulant was applied using a liquid stool atomizer, and an absorption test was performed using the plate liquid stool absorption test method. Target nonwoven material was the material described in this document. Then, the four corners of the liquid stool plate were adjusted to match the thickness of the nonwoven material and checked to make sure that the plate was level. The non-woven material was placed between the bottom and top plates and subjected to interaction with an HM simulant agent. The nonwoven fabric was left in the test facility for 2 minutes after the interaction, and then placed in a vacuum chamber to measure the amount of accumulation of the HMW simulant agent on the nonwoven fabric. Four paper towels were placed on top of the nonwoven fabric, and the nonwoven fabric was flipped so that the paper towels were on the bottom, over the vacuum chamber, and covered with a silicone sheet for vacuum sealing. The vacuum chamber was turned on by pressurizing 5 inches of water for 1 minute. In addition to the HM simulant collected with paper towels on the vacuum chamber, excess HM simulant remaining on the BM plate was removed using an additional paper towel. The amount of HMW simulant collected with paper towels from the vacuum chamber, together with excess HMW simulant remaining on the plate, was recorded as the total accumulated HMW simulant.

In each of the examples, three (N=3) samples were tested. The amounts of HMW simulant in each layer of the 3 samples were then averaged to obtain the amount of HMW simulant accumulated on the nonwoven fabric.

materials

fibers

Bicomponent void fibers having a diameter of 33 microns, a filament weight of 5.5 denier and a density of 0.705 g/cm ³ . Bicomponent fibers without voids, having a diameter of 33 microns, a filament weight of 7.1 denier and a density of 0.913 g/cm ³ . It should be noted that the density of the bicomponent fibers with voids was 23 percent less than the density of the bicomponent fibers without voids. Fiber density was measured using sag/float after thermal bonding of the web at 133°C. The fibers were cut into 18 mm lengths, then heat-set at 118° C. to a final length of 15 mm. The tested codes are listed in Table 1.

Table 1: Tested codes

code number Fiber Target basis weight, g/m ² one With voids thirty 2 With voids 60 3 With voids 120 four Without voids thirty 5 Without voids 60 6 Without voids 120

Three-dimensional foam-molded sheets tested herein were prepared by combining 300 grams of deionized water, 5 grams of 10% SDS, and fibers. The combination was mixed to form a foam and poured into an 8" by 8" by 2" frame. It was then treated with a template having 1 cm square holes, 40% porosity, and 12 mm thickness, with a nylon spunbond backing. This arrangement was dried and thermally bonded at 133°C for 1-1.5 hours. Then it was wetted by immersion in a solution of 0.2 wt. % SILWET brand DA63 surfactant in water and dried at ambient conditions.

Fecal mass simulant

The following is a description of the fecal material simulant A used in the examples described herein.

Ingredients:

• Dannon® Brand All Natural Low Fat Yogurt (1.5% Grade A Milk Fat), Vanilla with Other Natural Flavors in a 32 oz container.

• MCCORMICK brand ground turmeric

• Great Value® 100% Liquid Egg Whites

• Knox® brand unmodified gelatin, unflavored and in powder form

• DAWN® Super Concentrated Unaltered Flavored Dishwashing Detergent

• Distilled water

Note: All stool simulant ingredients can be purchased at grocery stores such as Wal-Mart® brand stores or online retailers. Some of the ingredients in fecal material simulant are perishable food products and should be included in fecal material simulant at least two weeks before their expiration date.

Mixing equipment:

• Laboratory scales with an accuracy of 0.01 grams

• 500 ml glass

• Small laboratory spatula

• Stopwatch

• Eurostar Power Control-Vise power control mixing device for viscous media with an IKA®-WERKE R 1312 turbine agitator, available from IKA Works, Inc., Wilmington, NC, USA.

Mixing procedure:

1. A 4-part mixture was prepared at room temperature by adding the following fecal material simulant ingredients (which are at room temperature) in the following order to a beaker at 21°C to 25°C: 57% yogurt, 3% turmeric, 39. 6% egg whites and 0.4% gelatin. For example, for a total mixture weight of 200.0 g, the mixture would contain 114.0 g yogurt, 6.0 g turmeric, 79.2 g egg whites, and 0.8 g gelatin.

2. Mixture of 4 components should be mixed until smooth using an IKA®-WERKE Eurostar stirrer set at 50 rpm. Uniformity will be achieved in about 5 minutes (when measured using a stopwatch). The position of the beaker can be adjusted during mixing so that the entire mixture is mixed evenly. If any of the materials in the mixture stick to the inside wall of the beaker, use a small spatula to scrape off the substance of the mixture from the inside wall and place it in the center of the beaker.

3. A 1.3% solution of DAWN Liquid Dishwashing Detergent was prepared by adding 1.3 grams of DAWN Super Strong Liquid Dishwashing Detergent to 98.7 grams of distilled water. A Eurostar and an IKA®-WERKE brand R 1312 Turbine were used to mix the solution for 5 minutes at 50 rpm.

4. A 1.3% DAWN Liquid Dishwashing Detergent solution at 2.0 grams was added to 200 grams of the 4-ingredient mixture from Step 2 to give a total combined weight of 202 grams of fecal material simulant. 2.0 grams of a 1.3% solution of DAWN brand liquid dishwashing detergent was mixed into a homogeneous mixture of 4 components carefully and only until smooth (about 2 minutes) at a speed of 50 rpm using an IKA®-WERKE Eurostar mixer . The final viscosity of the final fecal material simulant should be 390 ± 40 cP (centipoise) when measured at a shear rate of 10 s ^-1 and at a temperature of 37°C.

5. The fecal material simulant was left to equilibrate for approximately 24 hours in a refrigerator at 7°C. It can be stored in a sealed airtight container for up to 5 days at approximately 7°C. The fecal material simulant must be equilibrated at room temperature before use. It should be noted that several batches of fecal material simulant with a similar viscosity may be pooled. For example, five batches of fecal material simulant with a similar viscosity and weighing 200 grams each can be combined into one common container for a total volume of 1000 ^cc . It will take approximately 1 hour to equilibrate 1000 cc ^of fecal material simulant at room temperature.

results

The results of the leak tests are shown in FIG. 3 and 4. Three-dimensional nonwoven fabrics obtained by molding the foam using binder fibers, containing and not containing voids, in the tests behaved in a similar way. When compared to test results for TEXTOR branded nonwoven, testing of 3D foam molded nonwoven showed approximately half the % buildup at approximately half the basis weight. Three-dimensional foam-spun nonwovens with high basis weights exhibited less than 2% buildup. In addition, there is a higher level of HMW simulant passing through the three-dimensional foam-spun nonwoven, even at a basis weight of 60 g/m ² .

The results of the compression and air permeability tests are shown in FIG. 5 and 6. Three-dimensional foam molded nonwoven fabrics according to the present invention exhibit high compressive strength and high air permeability. In this model of tops and bottoms, the combination of open bottoms and compression-resistant tops is a combination that results in low % accumulation values.

The solutions described herein are nonwovens having high degrees of three-dimensional topography, high compressive strength and high levels of porosity. Such materials exhibit significantly better HMW absorption compared to current commercially available materials used in current products. The method of testing the absorption of BM through plates demonstrated that the three-dimensional fabric obtained by molding the foam according to the present invention can reduce the accumulation of BM up to 2 wt. % compared to 40 wt. % for TEXTOR brand nonwovens. BM accumulation values can be considered similar to rewet values and represent the amount of BM on the skin.

In a first specific aspect, a method for making a high topography nonwoven substrate includes providing a foam containing water and synthetic binder fibers; applying foam to a flat surface; placing the template mold on the foam opposite a flat surface to create a foam/mould assembly; heating the foam/mould assembly to dry the foam and bind the synthetic binder fibers; and removing the pattern from the substrate after heating the foam/mould assembly, wherein the substrate comprises a flat base layer having an X-Y surface and a surface on the reverse side opposite the X-Y surface; and a plurality of protruding elements integral with the X-Y surface and protruding from it in the Z direction, with each protruding element having a height, diameter or width, a cross section, a side wall, a proximal end at which the protruding element comes into contact with the base layer, and the far end opposite the proximal end, while the protruding elements are distributed in both directions X and Y, and the density of the protruding element is equal to the density of the base layer.

The second specific aspect includes the first specific aspect and is characterized in that the binder fibers are two- and/or multi-component binder fibers.

A third specific aspect includes the first and/or second aspect and is characterized in that the cross-sectional shape of the protrusion at the proximal end of the protrusion is the same as the cross-sectional shape of the protrusion at the distal end of the protrusion.

A fourth specific aspect includes one or more of aspects 1-3 wherein the cross-sectional shape of the protrusion at the proximal end of the protrusion differs from the cross-sectional shape of the protrusion at the distal end of the protrusion.

The fifth specific aspect includes one or more of aspects 1-4, wherein the cross-sectional shape of the projecting element is round, oval, rectangular or square.

The sixth specific aspect includes one or more of aspects 1-5, wherein the density of the protruding element at the proximal end of the protruding element is equal to the density of the protruding element at the distal end of the protruding element.

The seventh specific aspect includes one or more of aspects 1-6, wherein the basis weight of the protruding element at the proximal end of the protruding element is equal to the density of the protruding element at the distal end of the protruding element.

An eighth specific aspect includes one or more of aspects 1-7, wherein the cross-sectional dimension of the protrusion at the proximal end of the protrusion is different from the cross-sectional size of the protrusion at the distal end of the protrusion.

The ninth specific aspect includes one or more of aspects 1-8 and is characterized in that each projecting element has a uniform density.

The tenth specific aspect includes one or more of aspects 1-9 and is characterized in that the height of the protruding element is greater than the width or diameter of this protruding element.

An eleventh specific aspect includes one or more of aspects 1-10, wherein the substrate has a compressive strength that allows for a void volume of 20 cubic centimeters or more per gram of substrate at a pressure of 0.6 kPa.

The twelfth specific aspect includes one or more aspects 1-11, wherein the ratio of the height of the protruding element to the width or diameter of the protruding element is greater than 0.5.

The thirteenth specific aspect includes one or more aspects 1-12, wherein the height of the protruding element exceeds 3 mm.

A fourteenth specific aspect includes one or more of aspects 1-13 wherein the sidewalls have greater than 50 percent fibers oriented in the Z direction.

A fifteenth specific aspect includes one or more of aspects 1-14 wherein the synthetic binder fibers have an average length greater than 3 mm.

The sixteenth specific aspect includes one or more aspects 1-15, while the protruding elements have a density of from 0.001 to 0.02 g/cm ³ .

The seventeenth particular aspect includes one or more aspects 1-16, with the protruding elements evenly distributed in both X and Y directions.

In an eighteenth specific aspect, a method for manufacturing a high topography nonwoven substrate includes providing a foam containing water and synthetic binder fibers; applying foam to a flat surface; placing the template mold on the foam opposite a flat surface to create a foam/mould assembly; heating the foam/mould assembly to dry the foam and bind the synthetic binder fibers; and removing the template from the substrate after heating the foam/mould assembly, wherein the substrate contains synthetic binder fibers, wherein the fibers of the substrate are fully synthetic binder fibers; a flat base layer having an X-Y surface and a surface on the reverse side opposite the X-Y surface; and a plurality of protruding elements integral with the X-Y surface and protruding from it in the Z direction, with each protruding element having a height, diameter or width, a cross section, a side wall, a proximal end at which the protruding element comes into contact with the base layer, and a distal end opposite the proximal end, wherein the protrusions are distributed in both X and Y directions, wherein the cross-sectional shape of the protrusion at the proximal end of the protrusion is the same as the cross-sectional shape of the protrusion at the distal end of the protrusion, and the density of the protruding element is equal to the density of the base layer.

In a nineteenth specific aspect, a method for manufacturing a high topography nonwoven substrate includes providing a foam containing water and synthetic binder fibers; applying foam to a flat surface; placing the template mold on the foam opposite a flat surface to create a foam/mould assembly; heating the foam/mould assembly to dry the foam and bind the synthetic binder fibers; and removing the template from the substrate after heating the foam/mould assembly, wherein the substrate comprises synthetic binder fibers, wherein the substrate fibers are fully synthetic binder fibers, wherein the substrate comprises a flat base layer having an X-Y surface and a surface on the reverse side opposite X-Y surfaces; and a plurality of protruding elements integral with the X-Y surface and protruding from it in the Z direction, with each protruding element having a height, diameter or width, a cross section, a side wall, a proximal end at which the protruding element comes into contact with the base layer, and the distal end opposite the proximal end, wherein the protrusions are distributed in both X and Y directions, with each protrusion having a uniform density, wherein the height of the protrusion is greater than the width or diameter of that protrusion, and the density of the protrusion equal to the density of the base layer.

The twentieth specific aspect includes a nineteenth specific aspect, wherein the cross-sectional shape of the protruding member at the proximal end of the protruding member is the same as the cross-sectional shape of the protruding member at the distal end of the protruding member.

These and other modifications and variations of the present invention may be practiced by those skilled in the art without departing from the spirit and scope of the present invention, as more specifically set forth in the appended claims. In addition, it should be understood that aspects of the various aspects may be fully and partially interchangeable. Furthermore, those skilled in the art will appreciate that the foregoing description is by way of example only and is not intended to limit the invention described hereinafter in said claims.

Claims (38)

1. A method for manufacturing a high topography nonwoven substrate, the method comprising: creating a foam containing water and synthetic binder fibers; applying foam to a flat surface; placing the template mold on the foam opposite a flat surface to create a foam/mould assembly; heating the foam/mould assembly to dry the foam and bind the synthetic binder fibers; and removing the pattern from the substrate after heating the foam/mould assembly, wherein the substrate comprises a flat base layer having an X-Y surface and a surface on the reverse side opposite the X-Y surface, the base layer having a density; and a plurality of protruding elements integral with the X-Y surface and protruding from it in the Z direction, with each protruding element having a height, diameter or width, cross section, side wall, density, proximal end at which the protruding element enters contact with the base layer, and the distal end opposite the proximal end, with the protrusions distributed in both the X and Y directions, with the density of the protrusion equal to the density of the base layer, and the side walls having more than 50 percent of the fibers oriented in the Z direction . 2. Method according to claim 1, characterized in that the binder fibers are two-component and/or multi-component binder fibers. 3. The method of claim. 1, characterized in that the cross-sectional shape of the protruding element at the proximal end of the protruding element is the same as the cross-sectional shape of the protruding element at the distal end of the protruding element. 4. The method of claim. 1, characterized in that the cross-sectional shape of the protruding element at the proximal end of the protruding element is different from the cross-sectional shape of the protruding element at the distal end of the protruding element. 5. The method according to claim 1, characterized in that the cross-sectional shape of the protruding element is round, oval, rectangular or square. 6. The method of claim. 1, characterized in that the density of the protruding element at the proximal end of the protruding element is equal to the density of the protruding element at the far end of the protruding element. 7. The method of claim. 1, characterized in that the main weight of the protruding element at the proximal end of the protruding element is equal to the main weight of the protruding element at the far end of the protruding element. 8. The method of claim. 1, characterized in that the cross-sectional size of the protruding element at the proximal end of the protruding element is different from the cross-sectional size of the protruding element at the distal end of the protruding element. 9. The method according to claim 1, characterized in that each protruding element has a uniform density. 10. The method according to claim 1, characterized in that the height of the protruding element is greater than the width or diameter of this protruding element. 11. The method of claim. 1, characterized in that the substrate has a resistance to compression, which provides for a void volume of 20 cubic centimeters or more per gram of the substrate under a pressure of 0.6 kPa. 12. The method according to claim 1, characterized in that the ratio of the height of the protruding element to the width or diameter of the protruding element exceeds 0.5. 13. The method according to p. 1, characterized in that the height of the protruding element exceeds 3 mm. 14. The method according to claim 1, characterized in that the synthetic binder fibers have an average length of more than 3 mm. 15. The method according to p. 1, characterized in that the protruding elements have a density of 0.001 to 0.02 g/cm ³ . 16. The method according to claim 1, characterized in that the protruding elements are evenly distributed in both X and Y directions. 17. A method for manufacturing a high topography nonwoven substrate, the method comprising: creating a foam containing water and synthetic binder fibers; applying foam to a flat surface; placing the template mold on the foam opposite a flat surface to create a foam/mould assembly; heating the foam/mould assembly to dry the foam and bind the synthetic binder fibers; and removing the template from the substrate after heating the foam/mould assembly, wherein the substrate contains synthetic binder fibers and wherein all of the fibers of the substrate are synthetic binder fibers; wherein the flat base layer has an X-Y surface and a surface on the reverse side opposite to the X-Y surface, wherein the base layer has a density; and a plurality of protruding elements integral with the X-Y surface and protruding from it in the Z direction, with each protruding element having a height, diameter or width, cross section, side wall, density, proximal end at which the protruding element enters contact with the base layer, and a distal end opposite the proximal end, with the protrusions distributed in both X and Y directions, wherein the cross-sectional shape of the protrusion at the proximal end of the protrusion is the same as the cross-sectional shape of the protrusion at the far end projecting element, while the density of the projecting element is equal to the density of the base layer, and at the same time the side walls have more than 50 percent of the fibers oriented in the Z direction. 18. A method for manufacturing a high topography nonwoven substrate, the method comprising: creating a foam containing water and synthetic binder fibers; applying foam to a flat surface; placing the template mold on the foam opposite a flat surface to create a foam/mould assembly; heating the foam/mould assembly to dry the foam and bind the synthetic binder fibers; and removing the template from the substrate after heating the foam/mould assembly, wherein the substrate contains synthetic bond fibers and wherein all fibers of the substrate are synthetic bond fibers, wherein the substrate comprises a flat base layer having an X-Y surface and a surface on the reverse side opposite the surface X-Y, while the base layer has a density; and a plurality of protruding elements integral with the X-Y surface and protruding from it in the Z direction, with each protruding element having a height, diameter or width, cross section, side wall, density, proximal end at which the protruding element enters contact with the base layer, and the distal end opposite the proximal end, wherein the protrusions are distributed in both X and Y directions, with each protruding element having a uniform density, with the height of the protruding element being greater than the width or diameter of the protruding element, while the density of the protruding element is equal to the density of the base layer, and at the same time the side walls have more than 50 percent of the fibers oriented in the Z direction. 19. The method of claim 18, wherein the cross-sectional shape of the protrusion at the proximal end of the protrusion is the same as the cross-sectional shape of the protrusion at the far end of the protrusion.

Images