WO2017085089A1

WO2017085089A1 - Mechanically treated multilayer substrate

Info

Publication number: WO2017085089A1
Application number: PCT/EP2016/077790
Authority: WO
Inventors: Fabio Zampollo; Ivano Gagliardi
Original assignee: Teknoweb Materials S.R.L.
Priority date: 2015-11-19
Filing date: 2016-11-16
Publication date: 2017-05-26
Also published as: GB201520432D0

Abstract

The present invention relates to substrates exhibiting a hydrophobic surface that comprise fibrous composites that are post-formation mechanically treated. Such substrates are particularly suited in the application as wipes.

Description

MECHANICALLY TREATED MULTILAYER SUBSTRATE Field of the invention

The present invention relates to a wettable substrate with a hydrophobic material on its surface that comprises fibrous composites that are post-formation mechanically treated. Such substrates are particularly suited for the application as wipes.

Background

Wipes, comprising cellulose and other materials, preferably in a layered configuration are well known in the art, as well as on the market. Today, wipes are often made of spunlace material manufactured in general using a high-speed jets of water (hydro entangling) process to treat a fibrous web. As a result, nonwoven materials made by this method have specific properties, as soft handle, integrity, drape, conformability and relatively high strength. These are the major characteristics that make spunlace nonwovens preferred over other nonwovens to be used in wipes. Typically fibers in spunlace materials for wipes are Rayon® staple fibers to provide the desired level of absorbency.

Recently, a dry web forming technology as been developed by Teknoweb Materials, Italy, the "ARVELL® technology", has reached the markets through Harper Hygienics, Poland. In WO2012/020053 (BOMA) , a particular execution thereof has been described. However, there exists still the need for more balanced use-relevant properties, in particular technical requirements like strength, fuzziness, liquid handling properties on one side and user perception relevant properties like softness, hand / touch, opacity on the other side.

Summary

These and other objects of the present invention are achieved through a substrate, as well as a process and an equipment for making a substrate as defined in the appended claims, which are an integral part of the present description.

Brief description of the Figures

Fig. 1 A depicts schematically a substrate according to the present invention, and Fig IB a photomicrograph of such a substrate.

Fig. 2 A to E depict schematically suitable equipment set up for mechanical activation as useful in the present invention.

Fig. 3A and B show schematically substrates according to the present invention as may be made from composites as depicted in Fig. 4, exhibiting regions with differing properties with exemplary corresponding property profiles; Fig. 4 to E depict various composites useful for making a substrate according to the present invention.

Fig. 5A and B depict schematically equipment and process set-up according to the present invention.

Fig. 6 depicts schematically a further equipment and process set-up according to the present invention.

Same numerals describe same or equivalent features.

Detailed description

The present invention relates to a substrate and a method and an apparatus for the manufacturing of such a substrate.

Substrate

Such a substrate is useful as a wipe, for various applications, but is particularly useful when the wipe is intended come into contact with the skin of a human. Such wipes may be manufactured and sold as dry wipes or as pre-moistured or wet wipes. A substrate may also be employed as a component in articles, such as baby diapers, training pants, incontinence articles, feminine hygiene articles, or the like.

Such wipes may be intended for single use or for limited re-usability and to be discarded thereafter, such that flushability or degradability may be desired. Typically such wipes are used in a single sheet form, though wipes may be provided in a roll form, optionally with partial separation lines. Wipes comprise a fibrous substrate, as described in more detail herein below, and may comprise further additives, such as, but without limitation, lotions, cleansing agents, or absorbency enhancements substances.

Wipes maybe described by properties like basis weights, caliper, overall densities, or tensile strength. In particular wipes preferably exhibit a soft touch, as may be a composite effect of surface properties like friction but also bulk properties like compressibility. To a person skilled in the art all the properties are well known as being relevant and may be determined by well-established test methods as described in the test methods section herein below.

In one aspect, the present invention is a substrate that may very suitably be employed for wipes, such as by merely sheeting such substrates and/or finishing such as by applying additives.

Substrates are typically manufactured as roll stock goods, i.e. in a continuous process resulting in an essentially endless web material, that may be wound on rolls or spools, or that may be fed into boxes ("festooning"). Typically, the width of the substrate is wider than the width of the wipe into which they may converted. The substrates exhibit a length (x-), width (y-) and thickness (z-) extension, wherein the x-direction corresponds to the machine direction of the manufacturing process and equipment. The general use requirements for wipes, such as ranges of strength, thickness, or basis weights, as well as respective test methods are generally known in the art and apply similarly to the precursor webs. It is also well known, that wipes should exhibit good softness properties, such as may be evaluated by the known Kawabata test method criteria.

A substrate according to the present invention exhibits a particularly useful combination of strength, softness and fuzz properties. It comprises a layered composite, as described in more detail herein below. The substrate comprises several x-y-directionally extending first, second and third regions arranged in a predetermined and repeating pattern. At least one of these regions exhibits at least one property that is clearly different to the corresponding property of a further region. The difference is induced by mechanical treatment, and is primarily one of physical properties such as pore size, density, basis weight, each expressed on a local basis for the respective region. The regions are typically also clearly discernible by visual inspection or optical methods. For explanatory purposes, and without intending any limitation, Fig. 1A describes such a pattern, showing schematically a substrate 100 with first (110), second (120), and third (130) regions and Fig. IB shows a photomicrograph of such a substrate. The first regions 110 may be raised portions, second regions 120 may be depressions, and third regions 130 may be transition regions or side walls, all these explanatory terms when looking at the x- or length (10) and y- or width (20) extension of such a substrate (with the positive z-direction being directed towards the viewer).

The transition regions may have a wide extension for a gradual transition or may be almost non-existing for very sharp transition. Correspondingly, the boundaries of the regions may be clearly discernible, such as indicated in Fig. 1 A with first to third region boundaries 111 and second to third region boundaries 121.

Within the context of the present invention, the various regions are created from a composite, as described herein below, by post-formation mechanical treatment. This technology is well known in the art. Without intending a limitation, in a first execution, sometimes referred to as "ring-rolling" and e.g. described in US4806300 (Walton) or US6294710 (P&G), to all of which express reference is made with regard to the mechanical treatment, the composite is fed between two rolls with intermeshing circumferential grooves and valleys, thereby creating in the substrate essentially continuous and parallel MD-directionally extending first and second regions corresponding to the peak and valley floor with third region being the slopes or side walls. In Fig. 2A an equipment 200 for executing a mechanical treatment on a web 100 is depicted with a first roll 210 and a counter-rotating second roll 220, both comprising ridges 310 and valleys 320 and slopes 330. In a further execution, as known from e.g. US6620485, to which express reference is made with regard to the mechanical treatment, and schematically depicted in Fig. 2B, the intermeshing ridges 310 and valleys 320 of the treatment roll extend cross-directionally, thereby transforming a composite 1000 into a substrate 100 by creating essentially cross- directionally extending first, second and third regions. In Fig, 2B, a mechanical treatment equipment 200 is depicted with counter-rotating first and second rolls 210 and 220, respectively, each being equipped with intermeshing ridges, grooves and slopes 310, 320, and 330, respectively. The exact execution of the mechanical treatment as well as the resulting pattern is not particular limiting for the present invention, and rolls - or equivalents to rolls such a sufficiently rigid belt structures - with interdigitating protuberances may be employed. It is important that the created third (transition) region in the substrate exhibits at least one physical property that is distinct from at least one of the other regions. This is further explained with Fig. 3, schematically depicting property profiles across a substrate over a length in the x-y-plane, that may correspond to the x- direction 10 as shown, or y- direction 20 or any direction angled thereto (not shown). In Fig. 3 A, a height 30 or z-directional profile of a substrate 100 is schematically depicted with ridges 110, valleys 120, and slopes 130. In Fig. 3B, a density profile 40 is schematically depicted. In the left part, the local density in the first (e.g. ridges) and second (e.g. valley) region is essentially the same, but the densities in the third regions (slopes) decrease to a minimum and increase again. As depicted in the right part of Fig. 3B, the densities of the ridges do not need to be the same as in the valleys or the minimum of the densities in different slope regions do not need to be identical. Similar profiles may be determined for various properties, for example local pore size, wherein the gradient may be inflected, such that the larger pores size regions correspond to the third transition regions, or fiber or filament diameter, etc..

Among the many possible patterns in a substrate, the one as already depicted in Fig. 1A and IB is particularly preferred. It may be created by an equipment 200 respectively a process a schematically depicted in Fig. 2C to 2D.

Fig. 2C shows two counter-rotating and intermeshingly or interdigitatingly arranged rolls 210 and 220 with their radius 215 and 225, respectively, forming a gap wherein the circumferential direction is aligned with the machine direction, and that comprise protuberances 310 extending from surface 218 at a protuberance height 315. The protuberances exhibit: circumferentially or x-directionally 10 an essentially trapezoidal cross-sectional profile, see Fig. 2D, with between 3 and 10 mm at their ridge tip (ridge tip length 342), between 5 and 15 mm at the base (ridge base length 344), and being spaced apart at the base by 3 to 20 mm, (ridge valley length 346), here shown to be essentially the same as the ridge base length, but it may also be shorter or longer;

cross- or y-directionally 20 the protuberances 310 show an essentially rectangular profile, see Fig. 2E, with a ridge width 352, ridge spacing 356, and an essentially rectangular cross-sectional profile in cross-direction.

The roll 210 and 220 may be created from a series of toothed wheels or disks or rings 205, each having the ridges width 352, and an outer radius as the sum of the radius of the surface 218 plus the height of the protuberances 315 and which may range from 5 mm to 20 mm, e.g. 12 mm. The teeth have the form and shape of the protuberances as described above. A suitable number of disks are positioned adjacently on a common axis, each two separated by a spacer 208, such as shims or spacer disks or the like, exhibiting a shim width 209. In the preferred execution as shown in Fig. 2C, D, and E, each two adjacently positioned rings 205 are circumferentially offset by the ridge valley length 346, such that the protuberances of the neighboring ring 205 are positioned as indicated with dashed lines in Fig. 2D and 2E.

Obviously for a person skilled in the art, the sharp edges and corners as depicted in the drawings may exhibit a radius. Also, the flanks of the trapezes do not need to be symmetric. Optionally, the system may further comprise web guides 219 that may aid the removal of the web from the roll.

It should be noted that the mechanical treatment is distinct from bonding or consolidating a web or composite. Any compression exerted on the web in the mechanical treatment is aiming at non-permanently fixing or deforming certain portions of the web whilst fixing or deforming other portions. Even for the particular execution of increasing the temperature of the composite prior or during the mechanical treatment, as described herein below, this should primarily aid the incremental stretching in the transition or side wall regions, but rather not induce consolidation in particular not in these regions.

Without wishing to be bound by the theory, it is believed that the effect of the mechanical treatment on the liquid handling properties of the substrate is such that the at least one hydrophobic surface layer has better liquid permeation properties by the enlarged pores as created by the mechanical treatment therein.

As schematically and generally indicated in Fig. 2B, a substrate 100 may be created by subjecting a composite web 1000 to a mechanical treatment step as described in the above. Composite

Within the present context, the term "composite web" (or short "composite") refers to a web material that comprises several layers that are z-directionally positioned relative to each other, as defined by the relative positioning of surfaces of the layers towards another layer. Whilst it should not be seen limiting, the first and second opposite surfaces of the layers may represent "upper" and "lower" surfaces when these layers are put in a relation to a reference system, as may be a (lowermost) forming belt during the manufacturing process, or as may be a user oriented surface during use.

These surfaces may be readily discernible, though for very thin respectively low basis weight layers the surfaces may be described by an envelope circumscribing the components of this layer. For example, a low basis weight fibrous layer may exhibit pores that extend throughout the layer. Then the envelop of such a layer will be the smallest area envelop covering the z-directionally outermost elements of the layer. Also, two neighboring layers may be difficult to distinguish, as certain components of one layer may penetrate into the neighboring layer, such as when a fiber or filament of one layer sticks into a pore or opening of another layer, such that the envelops overlap or intersect. Then, a separation boundary surface will be determined by taking the means of the z-directional values in these overlap regions. However, a skilled person will also be able to determine the layers by the way of making the composite, when they are made by distinct processes representing preferred executions and as discussed herein below.

Each of the layers is essentially x-y-directionally homogeneous and typically extends over the full width and length of the composite, though there may be varying compositions on a micro scale, such as when two components or compounds in a layer are mixed and/or due to production variability.

The layers comprise components, such as particular types of fibers and filaments, as described herein after.

As depicted in schematic diagram 4A, a composite according to the present invention 1000 comprises at least four layers positioned z-directionally 30 relative to each other:

A first layer 1100 comprises a mixture of melt-extruded fibers or filaments of one or more thermoplastic compound(s) and short fibers, preferably natural fibers, more preferably pulp fibers, and exhibiting a first (1110) and a second (1120) first layer surface.

For the present invention, it is not particularly relevant how the melt-extruded filaments and the short fibers are created and mixed. Suitable approaches are known in the art, such as under the term "coform" or as described in US5948710 (K-C). A particularly suitable approach is described in WO2012/020053 (BOMA) wherein cellulosic fibers are combined with filaments. To both references express references is made with regard to forming such layers.

The first layer may further comprise other additives, such as absorbent particles, superabsorbent particles or fibers and the like.

The first layer may exhibit ranges for filament basis weights from about 3 to about 7 g/m², often between about 4 and about 6 g/ m², these filaments exhibiting a filament titer of between about 1.0 and about 2.5 dTex, preferably between about 1.2 and about 1.6 dTex. The first layer may exhibit basis weight ranges for the short fibers of from about 15 g / m² to about 60 g/m². A second layer 1200 comprises filaments of one or more thermoplastic compound, preferably of the spunmelt type, and exhibiting a first (1210) and a second (1220) second layer surface, wherein the second layer 1200 is positioned with its first surface 1210 oriented towards said second surface 1120 of said first layer.

The second layer may exhibit ranges for filament basis weights from about 3 to about 7 g/m², often between about 4 and about 6 g/ m², these filaments exhibiting a filament titer of between about 1.0 and about 2.5 dTex, preferably between about 1.2 and about 1.6 dTex. A third layer 1300 comprises filaments of one or more thermoplastic compound, preferably of the spunmelt type and exhibiting a first (1310) and a second (1320) third layer surface. The third layer 1300 is positioned with its second surface 1320 being oriented towards the first surface 1110 of the first layer 1100.

The third layer may exhibit ranges for filament basis weights from about 3 to about 7 g/m², often between about 4 and about 6 g/ m², these filaments exhibiting a filament titer of between about 1.0 and about 2.5 dTex, preferably between about 1.2 and about 1.6 dTex. A fourth layer 1400 comprises filaments of one or more thermoplastic compound, preferably of the meltblown type, these filaments forming a fibrous web exhibiting a fourth layer pore size distribution. The fourth layer 1400 exhibits a first (1410) and a second (1420) fourth layer surface and is positioned with its first fourth layer surface 1410 oriented towards the second surface 1220 of the second layer and its second fourth layer surface 1420 forms a second surface 1020 of said composite 1000.

The fourth layer may exhibit ranges for filament basis weights from about 1 to 5 g/m², often between 1.5 and 3 g/ m², these filaments exhibiting a filament diameter of between 1 μιη and 5 μιη, preferably between 1.5 and 3 μιη.

A skilled person will readily realize, that in the figures the z-directional distances between the layers are for ease of visibility only, but that in reality such layers will be in direct contact with each other, if not interpenetrating. Also, a composite according to Fig. 4A may be inverted as indicated in Fig. 4B, and the first surface 1410 of the fourth web 1400 may now form the first outer surface of the composite 1010.

Optionally, starting from structures as shown in Fig. 4A, the composite comprises a fifth layer 1500, as depicted in Fig. 4C and 4E, which comprises filaments of one or more thermoplastic compound/s, preferably of the meltblown type. These filaments form a fibrous web exhibiting a fifth layer pore size distribution and exhibit a first (1510) and a second (1520) fifth layer surface. The fifth layer is positioned with its second surface 1520 oriented towards the first surface 1310 of said third layer 1300, and with its first surface 1510 forming a first surface 1010 of the composite 1000.

The fifth layer may exhibit ranges for filament basis weights from about 1 to 5 g/m², often between 1.5 and 3 g/ m², these filaments exhibiting a filament diameter of between 1 μιη and 5 μιη, preferably between 1.5 and 3 μιη.

The composite may comprise additional layers or sub-layers that satisfy the general description of any of the other layers.

For example, as depicted in Fig. 4D and 4E, the first layer 1100 may comprise sublayers 1103 and 1107, each comprising a mixture of filaments, i.e. melt-extruded filaments of a thermoplastic compound, and short fibers, but which may exhibit a differing composition or different properties of the components or compounds.

It is important that at least one of the outer surfaces, preferably both is / are made of essentially hydrophobic material. Such a hydrophobicity may be reached by employing inherently hydrophobic compounds or by applying hydrophobization agents to less hydrophobic compounds.

Preferably, though not necessarily, the composite is formed in a continuous process, such as when a one layer is positioned on a support or forming belt and the other layers are added, optionally after the first formed layer(s) have left the forming belt. This implies that a composite exhibits sufficient self supporting strength which may be enhanced by a bonding step that may be executed after the composite is formed and/or as an interim step for bonding or consolidating one or more layer(s) prior to the formation of the composite. This includes that the composite is manufactured in one sub-process, then stored on rolls, reels, boxes or other suitable means, to be then transferred to an equipment for executing the mechanical treatment.

In order to impart required or desired physical integrity to the composite, the composite is a bonded composite. Within the present context, bonding may refer to various features. Layers of the composite may have inherent bonding, such as when compounds or filaments in a molten or softened state attach to other compounds or components, such as when melt- extruded filaments are attaching to short or preformed fibers, or when fibers or filaments of a layer are attaching to a previously laid layer. Also, within one layer, the filaments may be attaching to each other upon lay-down. Typically, however, these kinds of bonding do not provide sufficient strength or integrity to satisfy processing and/or in-use requirements, such that additional bonding may be provided. The type of bonding is not considered critical in the current context, as long as in addition to usual requirements like strength and softness, the pore size and hydrophobicity requirements at least for the outermost layers of the composite are not compromised. Henceforce, melt fusion bonding is a preferred execution, such as by through air bonding, thermal embossing, pressure bonding, ultrasonic bonding and the like alone or in combination as well known in the art.

Components

The layers of the composite according to the present invention comprise components. All layers comprise fibers and may essentially (more than 80% by weight) or at least predominantly (more than 50% by weight) consist of fibers. Fibers exhibit a high L/D ratio, typically more than 10, and may be essentially continuous, broken, crimped, and may be man-made or natural based.

Fiber diameter can be readily determined by optical methods, as well known in the art. All layers of a composite according to the present invention comprise melt-extrudable fibers, herein also referred to as filaments that are made from thermoplastic compounds, typically polymers, often synthetic compounds. The filaments may be extruded in various cross-sectional shapes, such as circular, elliptical, bi- or multi-lobal, including so called bi- or multicomponent filaments, and may be essentially continuous or broken or cut filaments. Filaments are preferably formed„in situ" and can be formed by many processes such as meltblowing or spunlaying. As used herein, "spunlaid" refers to filaments made by well known spundbonding technology without having undergone further processing, such as bonding. Filaments are classified by their diameter that for the present applications typically range from more than about 30 μιη to less than about 1 μιη (coarse, fine, super fine micro-denier, micro-fibers, down to nano-fibers) or by their titer, expressed in dTex (gram per 10000 m), ranging from more than about 5 dTex, but preferably not more than about 2.5 dTex to less than 0.007 dTex.

Depending on the degree of stretching or drawing whilst the filaments are in a molten or deformable state, they may be referred to as melt blown or spun filaments. However, more recent technologies make such distinction ambiguous, such that within the present context the fiber diameter as well as the pore radius of the layer are considered to be descriptive distinctions.

Nonetheless, according to conventional nomenclature the filaments for the first, second and third layer may be spun fibers exhibiting typically a diameter of less than 30 μιη, preferably less than bout 17 μηι, but more than 12 μηι, preferably more than 13 μιη. Typical fibers may exhibit a titer of less than about 3 dTex, preferably less than 1.5 dTex, but more than 1.0 dTex, preferably more than 1.2 dTex, whereby the titer correlates with the filament diameter for given polymer densities. Such fibers may be essentially endless fibers that may be deposited in a random manner on a deposition belt or a pre-formed layer.

Accordingly, the filaments of the fourth and fifth layer may be meltblown fibers that may typically exhibit diameters of less than about 5 μηι, preferably less than about 3 μηι, and more than about 1 μιη, preferably more than about 1.5 μιη. Such fibers may be essentially endless at the extruder, though they may break up during the transfer to the deposition region and typically exhibit a length of more than 5 mm or even more than 10 mm.

The first layer further comprises short fibers. In the present context, the term "short fiber" should be seen in relation to the length of the other filaments, such that "short fibers" exhibit a length of typically less than 5 mm, though length up to 10 mm can also be considered a short fiber. Short fibers do not need to be made in situ but are preferably introduced into the process already in the fiber form. Whilst it is also within the scope of the present invention that short fibers are man-made or synthetic fibers, such as Rayon ® fibers, preferred short fibers are natural fibers such as cellulosic fibers like pulp fibers.

Compounds

The filaments can be made from a multitude of thermoplastic materials. In a particular execution, the filament forming compounds comprise polyolefins, though not necessarily identical types, more particularly polypropylene or polyethylene, or bicomponent filaments made of such materials. However, other materials can be readily employed, such as polyester or degradable polymer such as without intending any limitation derivatives of lactones, butyrates, etc. or hydrophobic polymers such as poly(e -caprolactone), polyhydroxyalkanoate, polybutylene succinate, polybutylene succinate adipate, polylactic acid, polybutylene adipate terphtalate, polydioxanone and polyglycolic acid, or mixtures or blends thereof.

It should be noted, that the various components can be employed in the various layers, but the individual layers may comprise different components.

However, it is important that the outermost layer of the composite comprises material that makes this layer hydrophobic, such when the composite does not allow drops of distilled water to penetrate into the composite prior to the mechanical treatment.

Within the present context, the term "hydrophobicity" refers to the inherent property of the compounds from which the components are formed, and it may be achieved by a number of ways.

First, in the simplest and most preferred execution, inherently hydrophobic compounds such a polyolefins may be employed and not be rendered more hydrophilic by surface or resin additives, such as typically employed when polyolefin web are intended to be used as liquid permeable layers, such as topsheet in absorbent articles.

Second, any compound may be rendered more hydrophobic by the addition of hydrophobization aids, such as - without limitation - silicone compounds.

The surface properties hydrophobic respectively hydrophilic should be seen in contrast to the wettability of a structure as may be improved by increasing the pore size of the structure, thereby easing liquid penetration into the structure. Further, the first layer comprises short fibers, preferably provided as pre-formed fibers of non-continuous length, preferably hydrophilic, such as many natural materials, and preferably are preferably cellulosic, most preferably wood pulp fibers.

Thus the effect of this aspect of the present invention is a particular improvement of a substrate suitable for being used as a wipe or a liquid handling material, that results from exploiting the benefits of known dry formed composites and combining these with a surface layer with particular properties. A layer of relatively hydrophobic fibers or filaments that are finer than the fibers or filaments of the underlying layers and exhibit a smaller pore size improves on softness, opacity and strength. However, such a layer may deteriorate liquid handling properties in spite of otherwise well performing layers in the interior. Surprisingly, the inventors have identified that creating regions with varying properties such as may be achieved by mechanical treatment of a composite with such a surface layer to compensate for the reduction in fluid handling properties, thus rendering a poorly or non- wettable material more wettable, such as can be determined by the drop test.

In a further aspect, the present invention relates to a process as well as the respective equipment 2000 for the manufacturing of suitable composites and substrates, see Fig. 5A and B.

Thus, the melt-extrudable materials are provided in supply system, typically in the form of pellets or granules and fed - either pure compounds, pre-mixed, or in-line mixed with other compounds - to an extruder, where they are molten. They are then pressed through orifices into filaments, which may then be contacted with a fluid, typically air, which may draw these filaments, and/or cool these, and/or leave them essentially continuous or break these up into shorter filaments. All these techniques are well known, such as under the terms of spunmelting, meltblowing, etc.

For the making of the first layer, additional material, such as cellulosic fibers is introduced, as also well known from US5948710 ( -C) or as a particularly preferred execution in WO2012/020053 (BOMA).

Considering the making of the first layer is a first layer forming system 2100, short fibers are provided in a short fiber supply system 2120 and mixed with filaments formed in a first melt- extrusion system 2110. The mixture is deposited on a forming belt 2600, the movement of which corresponds to the machine direction 10 of the overall system, in a first deposition region 2610. The forming belt as such is well known in the art, and it may be gas permeable, such as to allow aiding of the deposition such as by applying vacuum underneath the forming belt.

Machine-directionally prior to the first deposition zone 2610, the second layer is positioned in a second layer deposition region 2620 by forming filaments in a second melt- extrusion system 2210, optionally drawing these prior to depositing.

Machine-directionally after the first deposition zone 2610, the third layer is positioned in a third layer deposition region 2630 by forming filaments in a third melt- extrusion system 2310, optionally drawing these prior to depositing.

The fourth layer is applied by a fourth melt- extrusion system 2400, that is positioned such that it can form an outer layer of the composite respectively substrate.

In a first variant, as depicted in Fig. 5A, this can be achieved by depositing the fourth layer prior to the second layer in a fourth deposition region 2410 by a melt- extrusion system 2400.

In a second variant, as depicted in Fig. 5B, this can be achieved by depositing the fourth layer after the third layer in a fourth deposition region 2410' by a melt- extrusion system 2400'.

In yet a third variant, as also included in Fig. 5B, this can be achieved by depositing the fourth layer after the precursor of the composite has left the deposition belt and the fourth layer can be applied onto the second surface 1220 of the second layer. In Fig. 5B, this is indicated by positioning the fourth melt- extrusion system 2400" underneath the precursor and applying the fourth layers in the fourth deposition region 2410".

It is important that the fourth melt- extrusion system is adapted to produce distinctly smaller diameter filaments than the second and third melt extrusion system. A skilled person will readily realize that if spunbonding is an appropriate system for the second and third layer, meltblowing may be an adequate method for the fourth layer.

Applying the optional fifth layer can be done analogously to the fourth layer, such that the fourth and fifth layer may form the outer surfaces 1010 and 1020 of the composite respective substrate. Typically, the precursor composite is submitted to a further bonding step, with melt fusion bonding as a preferred execution, such as by through air bonding, thermal embossing, pressure bonding, ultra-sonic bonding and the like alone or in combination as well known in the art.

As depicted in Fig. 5 A, and B, a precursor of the composite is fed through a composite bonding equipment 2700 to form the bonded composite 1000.

Thereafter, the bonded composite 1000 is fed to the mechanical activation unit 200, as described in more detail herein above.

The system may further comprise a process end section unit comprising a system selected from the group consisting of

- a web transfer unit for transferring said substrate continuously to further process units;

- a winder or a festooning unit for creating batches of substrate, optionally including a slitting unit for creating substrate strips by separating said substrate along essentially longitudinally extending separation lines;

- a separation unit for separating said substrate into individual substrate pieces, optionally combined with a packaging unit for packing single or a multiplicity of substrate pieces. Optionally, the mechanical activation may be eased and/ or enhanced by thermally treating the composite during or prior to the mechanical activation. Without wishing to be bound be the theory, it is believed that when the thermoplastic material, and in particular of the filaments of the outer layers, is heated until it becomes plastically deformable, e.g. reaching its Vicat Softening Point temperature, but below its melting point, the mechanical activation becomes more effective. To this end additional heating equipment may be installed, and then preferably also cooling equipment to minimize the deformation once the substrate is reaching the process end point and may be would up again, as this typically results in compression that may deteriorate the substrate structure again. Thus, as depicted schematically in Fig. 6 exemplarily, but not limiting, an equipment for and a process similar to the one as shown in Fig. 5A is complemented by a heating unit 2800 prior to the mechanical activation unit 200 and a cooling unit 2900 just thereafter. The heating unit may be a heated roll or any other heating tool, with infrared heating being a preferred execution. The cooling unit can be a chill roll or any other cooling medium known in the art. In a complementary or alternative setup, the mechanical activation tool may be heated, here indicated by 200'. In a further complementary or alternative step, the bonding equipment may comprise heating of the web outside of the bonding regions. The composite material prior the heating step is referred to as 1000, after the heating step 1000'. And the mechanically treated, but not yet cooled substrate is referred to as 100'. Optionally, the process may be operated such that the composite forming and bonding is performed first, and the composite may be rolled up, spooled, or boxed to be further transferred and/or optionally stored before further processed by the mechanical treatment. Accordingly, the mechanical treatment step may executed in-line with further processing of the substrate, such as creating final articles comprising such a substrate.

Test Methods

Test methods suitable for assessing the present invention materials are well known and described e.g. by the ED ANA Nonwovens Standard Procedures, preferably the 2015 Edition, (see http://www.edana.org/discover-nonwovens/standard-procedures) of which in particular the following test methods are of interest in the present context:

Measuring the Rate of Sorption of Wiping Materials NWSP 010.2.R1 (15)

Surface Wetting Spray Test NWSP 080.1.R0 (15)

Nonwovens Run Off NWSP 080.9.R0 (15)

Thickness of Nonwoven Fabrics (INDA) NWSP 120.1.R0 (15)

Mass per Unit Area NWSP 130.1.R0 (15)

Resistance to Linting of Nonwoven Fabric (Dry) NWSP 160.1.R0 (15)

Aqueous Method for Determining Releases of Particulates (Wet) NWSP 160.2.R0

(15)

Internal Bond Strength of Nonwoven Fabrics NWSP 110.3.R0 (15)

Breaking Force and Elongation of Nonwoven Materials (Strip Method) NWSP

110.4.R0 (15)

Stiffness of Nonwoven Fabrics Using the Gurley Tester NWSP 090.2.R0 (15) Handle-O-Meter Stiffness of Nonwoven Fabrics NWSP 090.3.R0 (15)

Pore size distribution testing can be made with a PSM 165 capillary flow pore size meter from the company TOPAS GmbH, Germany, using "Topor" test fluid (at 16 mN/cm surface tension) or Triton X-100 (at 31 mN/cm surface tension). The instrument is capable of measuring interconnected pores in the size range of 0.23 μιη to 130 μιη.

All of these methods are directed towards determination of macroscopic properties of a web, and may be well used to describe a substrate, a composite as well as the differences between these, such as induced by the mechanical treatment.

However, such methods ae not suited to determine and compare properties of individual regions of a substrate according to the present invention, in particular a local surface pore size and local surface fiber or filament diameters. Such values can be suitably established by microphotographic analysis of sample areas sufficiently small to allow distinction of relevant regions. Examples

As a first comparative material, a material commercially available such as from Teknoweb Materials, Italy under the trade name ARVELL at 50 g/m² has been used. It exhibits a five layer structure:

A first layer comprises two sublayers, each made of spunlaid PP filaments of about 1.4 dTex at a basis weight of about 5 g/m² mixed with cellulose fluff fibers as short fibers at about 25 g/m². This layer has been formed according to the teaching of WO2014/020053, to which already express reference has been made.

A second and a third layer enveloping the first layer are each made of spunlaid PP filaments at about 1.4 dTex at a basis weight of about 5 g/m².

A fourth and a fifth layer are positioned between the second and third layers and the first layer, respectively, each of filaments of about 2 μιη and at a basis weight of about 2 g/m², as may be made by meltblowing.

The composite is bonded by a pattern of circular bond points.

Whilst the outer layers have not been hydrophilized, a drop of distilled water positioned on the surface penetrates readily into the structure.

A second comparative material has been prepared analogously, except that the fourth and fifth layer are not positioned inside, but on the outside of the composite, i.e. neighboring the second and third layer respectively.

The material exhibits an improved softness and hand.

However, without hydrophilization, a drop of distilled water penetrates not or less readily into the structure.

A first inventive example has been prepared by mechanically treating a composite according to the second comparative material.

The material exhibits a pattern as described above, with raised regions and valley regions and transition regions as shown if Fig. 2A and 2B.

The material exhibits a significantly improved softness and hand and drops of distilled water penetrate readily into the substrates in particular when the drop is positioned on a transition region.

Claims

1. A fiber containing substrate

exhibiting a length (x-), width (y-) and thickness (z-) extension,

comprising a composite web and

further comprising first, second and third regions forming x-y-directionally predetermined pattern,

said composite web comprising in z-directional arrangement

i) a first layer comprising a mixture of

filaments of one or more thermoplastic compound/s and

short fibers, preferably natural fibers, more preferably pulp fibers, and exhibiting a first and a second first layer surface;

ii) a second layer

comprising

filaments of one or more thermoplastic compound/s, preferably of the spunlaid type,

and exhibiting a first and a second second layer surface,

said second layer being positioned

with its first surface oriented towards said second surface of said first layer;

iii) a third layer

comprising

filaments of one or more thermoplastic compound/s preferably of the spunlaid type,

and exhibiting a first and a second third layer surface,

said third layer being positioned with its second surface

oriented towards said first surface of said first layer;

iv) a fourth layer

comprising

filaments of one or more thermoplastic compound/s, preferably of the meltblown type,

said filaments forming a fibrous web exhibiting a fifth layer pore size distribution

and exhibiting a first and a second fourth layer surface,

said fourth layer being positioned

with its first surface oriented towards said second surface of said second layer and with its second surface forming a second surface of said composite;

v) optionally a fifth layer

comprising

filaments of one or more thermoplastic compound(s), preferably of the meltblown type,

said filaments forming a fibrous web exhibiting a fifth layer pore size distribution and

exhibiting a first and a second fifth layer surface;

said fifth layer being positioned

with its second surface being oriented towards said first surface of said third layer, and

with its first surface forming a first surface of the composite, wherein fibers or filaments of at least said second, third, fourth and said optional fifth layer exhibit an average fiber diameter, respectively,

wherein

said fibers or filaments of said fourth layer exhibits a smaller average fiber diameter than of said second layer,

and, if present, said fibers or filaments of said fifth layer exhibits a smaller average fiber diameter than of said fibers of said third layer,

and wherein

said fourth layer and, if present, optionally said fifth layer are essentially free of a hydrophilization agent.

2. A substrate according to claim 1, wherein at least said fourth and, if present, said fifth layer exhibit/s a pore size distribution, that is distinctly different in at least one of said regions.

3. A substrate according to claim 1 or 2, wherein one or more, preferably all of said thermoplastic compounds are selected from the group consisting of polyolefins and biodegradable resins.

4. A fiber containing substrate

comprising in a z-directional arrangement

a mixture of filaments of one or more thermoplastic compound(s) and short fibers, preferably natural fibers, more preferably pulp fibers, said mixture being sandwiched between two layers of spunlaid webs,

wherein at least a further layer of a meltblown web is positioned as the outer surface of the substrate,

wherein further said meltblown web is essentially free of hydrophilizing agent, said substrate further comprising first, second and third regions forming x-y-directionally a predetermined pattern of ridges, valleys and transitional side walls between ridges and valleys.

5. An article comprising a fiber containing substrate according to any of the preceding claims, said article being selected from the group consisting of

wipes, preferably for being used on human skin,

absorbent articles more preferably selected from the group consisting of

baby diapers;

training pants;

- incontinence articles;

feminine hygiene articles.

6. A process for manufacturing a substrate

said process comprising the steps of

1) providing

1.1) as equipment

1.1.1) an essentially endless forming belt defining the machine direction of said process;

1.1.2) a fiber mixture creating unit comprising a first melt- extrusion unit and a short fiber delivering system adapted

to create a mixture of filaments and short fibers, preferably natural fibers, more preferably pulp fibers and

to deliver said mixture to said forming belt in a first deposition region for forming a first layer;

1.1.3) a second melt extrusion unit for depositing filaments on said forming belt in a second deposition region upstream of said first deposition region, thereby forming a second layer;

1.1.4) a third melt extrusion unit for depositing filaments on said forming belt at a third deposition region downstream of said first deposition region, thereby forming a third layer;

1.1.5) a fourth melt extrusion unit for providing a layer of filaments positioned upstream of said second melt extrusion unit or downstream of said third melt extrusion unit, 1.1.6) a mechanical treatment station positioned downstream of said second melt- extrusion deposition region,

1.2) as materials

1.2.2) short fiber material, preferably pulp;

1.2.3) one or more types of thermoplastic material suitable for forming filaments by melt- extrusion, preferably selected from the group consisting of one or more types of polyolefin and one or more types of degradable polymer;

2) creating a fibrous composite by performing the following sub-steps in the following order:

2.1) optionally creating fourth layer fibers and depositing a fourth layer onto said forming belt;

2.2) forming second layer fibers and depositing a second layer onto said forming belt or, if present, said fourth layer;

2.3) creating a fiber mixture and depositing a first layer on said second layer;

2.4) creating third layer fibers and depositing a third layer on said first layer;

2.5) optionally creating fifth layer fibers and depositing a fifth layer on said third layer;

2.6) optionally, creating fourth layer fibers and depositing said fourth layer, unless deposited in step 2.1, on said second layer,

wherein at least one of said steps 2.1), 2.5 and 2.6) is executed;

3) submitting said fibrous composite to a post-formation treatment step of mechanical activation,

wherein

at least one of said fourth or fifth layers is deposited forming an outside surface of said substrate;

wherein further said fourth or fifth layer fibers are created exhibiting a smaller average fiber diameter than said second or third layer fibers.

7. A process according to claim 6, wherein said post formation treatment step comprises the feeding of said composite through a nip of counter-rotating rolls each exhibiting protrusions and valleys in an inter- digitating relationship.

8. A process according to claim 6 or 7, further comprising one or more steps selected from the group consisting of

4) bonding said composite in a additionally provided bonding unit;

5) winding, storing or transferring said fibrous composite before submitting it the post- formation treatment step in additionally provided winding, storage or transfer units, respectively;

6) heating at least a portion of said composite prior to mechanically treating it in an additionally provided heating unit, preferably an infrared heating unit;

7) heating at least a portion of said composite whilst mechanically treating it;

8) cooling said mechanically treated substrate in an additionally provided chill unit;

9) winding, storing or transferring said mechanically treated substrate, if present, after the cooling step in additionally provided winding, storage or transfer unit.

9. A manufacturing equipment for the making of a fiber containing substrate,

said equipment comprising

1.1.1) an essentially endless forming belt defining the machine direction of said equipment;

- to create a mixture of filaments and short fibers, preferably natural fibers, more preferably pulp fibers and

- to deposit said mixture on said forming belt in a first deposition region;

1.1.3) a second melt extrusion unit for depositing filaments on said forming belt at a second deposition region upstream of said first deposition region;

1.1.4) a third melt extrusion unit for depositing filaments on said forming belt at a third deposition region downstream of said first deposition region;

1.1.5) a fourth melt extrusion unit for depositing filaments on said forming belt at a fourth deposition region,

wherein said fourth melt extrusion unit creates filaments exhibiting a smaller average fiber diameter than said second melt extrusion unit creates,

and in that it comprises a mechanical treatment unit positioned downstream of said second melt- extrusion deposition region.

10. An equipment according to claim 9, further comprising one or more elements from the group consisting of

4) a bonding unit positioned upstream of said mechanical treatment unit;

5) a winding, a storing or a transferring unit positioned upstream of said mechanical treatment unit;

6) a heating unit, preferably an infrared heating unit positioned prior to said mechanical treatment unit;

7) a heating element integral with said mechanical treatment unit; 8) a chill unit positioned downstream of said mechanical treatment unit;

9) a winding, a storage or a transfer unit positioned after said mechanical treatment unit and after said chill unit, if present.