HK1105210A - Polymeric structures and method for making same - Google Patents

Description

Polymeric structures and methods of making the same

Technical Field

The present invention relates to polymeric structures comprising non-PVOH processed hydroxyl polymer compositions comprising hydroxyl polymers. The invention also relates to fibrous structures comprising such polymeric structures, and to methods for making the polymeric structures.

Background

In recent years, fiber structure formulators have attempted to switch from wood-based cellulosic fibers to polymeric fibers. Fibrous structures comprising polymer fibers are known in the art, see for example EP 1217106 a 1.

However, such prior art attempts to make fibrous structures containing polymeric fibers have failed to achieve their strength properties in-kind for fibrous structures based on wood-based cellulose-containing fibers.

Accordingly, there is a need for a polymeric structure and/or fibrous structure comprising a polymeric structure in the form of fibers, the polymeric structure and fibrous structure exhibiting strength properties substantially similar to or superior to those of wood-based fibrous structures comprising cellulosic fibers.

Summary of The Invention

The present invention meets the above-described needs by providing a polymeric structure and/or a fibrous structure comprising a polymeric structure in the form of fibers. The polymeric structures and fibrous structures exhibit substantially similar or better strength properties than fibrous structures based on wood that contain cellulosic fibers.

In one aspect of the invention, a polymeric structure comprising a non-PVOH processed hydroxyl polymer composition comprising a hydroxyl polymer is provided, wherein the polymeric structure exhibits a stretch at peak load of at least about 5% and/or at least about 8% and/or at least about 10%, and/or a stretch at failure load of at least about 10% and/or at least about 13% and/or at least about 20%.

In another aspect of the present invention, a fibrous structure comprising a polymeric structure in the form of fibers according to the present invention is provided, wherein the fibrous structure exhibits a stretch at peak load of at least about 5% and/or at least about 8% and/or at least about 10% and/or a stretch at break load of at least about 10% and/or at least about 13% and/or at least about 20%.

In another aspect of the invention, a fibrous product comprising one or more fibrous structures according to the present invention is provided.

In another aspect of the present invention, there is provided a method for making a polymeric structure, the method comprising the steps of:

a. providing a non-PVOH polymer melt composition comprising a hydroxyl polymer; and

b. polymer processing the non-PVOH polymer melt composition to form a polymeric structure;

wherein the polymeric structure exhibits a stretch at peak load of at least about 5% and/or at least about 8% and/or at least about 10%, and/or a stretch at failure load of at least about 10% and/or at least about 13% and/or at least about 20%.

In another aspect of the invention, a polymeric structure in the form of a fiber produced according to the method of the invention is provided.

In another aspect of the invention, a method for making a fibrous structure is provided, the method comprising the steps of:

a. providing a non-PVOH polymer melt composition comprising a hydroxyl polymer;

b. polymer processing the non-PVOH polymer melt composition to form a polymeric structure in the form of a fiber; and

c. incorporating the polymeric structure in fiber form into a fiber structure;

wherein the fibrous structure exhibits a stretch at peak load of at least about 5% and/or at least about 8% and/or at least about 10%, and/or a stretch at failure load of at least about 10% and/or at least about 13% and/or at least about 20%.

In another aspect of the present invention, a fibrous structure comprising two or more fibers wherein at least one fiber comprises a polymeric structure in the form of a fiber is provided, wherein the fibrous structure comprises a first region comprising associated fibers and a second region comprising non-associated fibers.

In another aspect of the invention, a fibrous product comprising one or more fibrous structures comprising a first region comprising associated fibers and a second region comprising unassociated fibers is provided.

In another aspect of the invention, a method for making a fibrous structure is provided, the method comprising the steps of:

a. providing a fibrous structure comprising two or more fibers, wherein at least one of said fibers comprises a polymeric structure in the form of a fiber; and

b. two or more fibers are associated with each other such that a fibrous structure is formed that includes a first region comprised of associated fibers and a second region comprised of unassociated fibers.

Accordingly, the present invention provides a polymeric structure, a fibrous structure comprising a polymeric structure in the form of fibers, a fibrous product comprising one or more of such fibrous structures, a process for making such a polymeric structure, a process for making such a fibrous structure comprising a polymeric structure in the form of fibers, and polymeric structures in the form of fibers produced by such a process.

Brief Description of Drawings

FIG. 1 is a schematic illustration of a method for making a polymeric structure according to the present invention.

FIG. 2 is a schematic view of a camera mount suitable for use in the lint/pilling test method described herein.

Detailed Description

Definition of

As used herein, "polymeric structure" refers to any physical structure formed by polymer processing of the non-PVOH polymer melt composition of the present invention. Non-limiting examples of such polymeric structures include fibers, films, and foams. The polymeric structures described above may be used, particularly when in the form of fibers, optionally together with other physical structures such as cellulosic fibers and thermoplastic water-insoluble polymeric fibers, to form fibrous structures. Preferably, the polymeric structures of the present invention have no melting point overall, or in other words the polymeric structures are non-thermoplastic polymeric structures. It is also desirable that the polymeric structure of the present invention be substantially uniform.

As used herein, the term "non-PVOH" means that very little, such as less than 5% and/or less than 3% and/or less than 1% and/or less than 0.5% by weight, of the polyvinyl alcohol is present in the composition and/or polymeric structure. In a preferred embodiment, 0% of the polyvinyl alcohol is present in the composition and/or polymeric structure.

As used herein, "destructive stretching" is defined by the formula:

wherein:

"the length of the polymeric structure FL" is the length of the polymeric structure at the time of breaking the load;

the "length of the polymeric structure I" is the initial length of the polymeric structure prior to stretching.

As used herein, "maximum stretch" is defined by the formula:

wherein:

"the length of the polymeric structure PL" is the length of the polymeric structure at peak load;

the "length of the polymeric structure I" is the initial length of the polymeric structure prior to stretching.

The strength of the polymeric structure can be determined by measuring the total dry tensile strength (MD and CD) or "TDT" of the polymeric structure. TDT or stretch is determined by providing a strip of 2.5cm x 12.7cm (one (1) inch by five (5) inches) of polymeric structure and/or a fibrous product comprising the polymeric structure to be tested as described above. Each strip was placed on a model 1122 electronic tension tester, commercially available from Instron Corp. (Canton, Massachusetts). The chuck speed of the tensile tester was about 5.1 cm/minute (2.0 inches per minute) and the gauge length was about 2.54cm (1.0 inch). The tensile tester calculates the tension at peak load and the tension at break load. The tensile tester calculates the stretch mainly by the above formula. As used herein, the peak load stretch is the average stretch at the MD and CD peak loads. As used herein, tensile at failure load is the average tensile at MD and CD failure loads.

The "machine direction" (or MD) is the direction parallel to the direction of flow of the polymeric structure through the manufacturing apparatus.

The "cross direction" (or CD) is the direction perpendicular to the machine direction and parallel to the general plane of the polymeric structure.

The term "fiber" as used herein refers to an elongated, thin, and highly flexible object having a long axis that is very long relative to two mutually orthogonal axes of the fiber, which are perpendicular to the long axis. The aspect ratio of the length of the major axis to the equivalent diameter of the cross-section of the fiber perpendicular to the major axis is preferably greater than 100/1, more specifically greater than 500/1, and still more specifically greater than 1000/1, and even more specifically greater than 5000/1.

The fibers of the present invention may be continuous or substantially continuous. A fiber is continuous if it is extensible 100% in the MD length of the fibrous structure and/or fibrous product made therefrom. In one embodiment, a fiber is substantially continuous if it is extensible by greater than about 30% and/or greater than about 50% and/or greater than about 70% in the MD length of the fibrous structure and/or fibrous product made therefrom.

The fibers may have a fiber diameter of less than about 50 microns, and/or less than about 20 microns, and/or less than about 10 microns, and/or less than about 8 microns, and/or less than about 6 microns, as determined by the term "fiber diameter test method" as described herein.

The polymeric structures of the present invention, and particularly the fibers of the present invention, can be made by crosslinking hydroxyl polymers together. In one embodiment, the polymeric structures formed by crosslinking, particularly in fiber form, generally exhibit no melting point. In other words, it degrades before melting. Non-limiting examples of suitable crosslinking systems for achieving crosslinking include crosslinking agents, by which the hydroxyl polymer can be crosslinked, and optionally crosslinking promoters.

Fibers comprising hydroxyl polymers can include melt spun fibers, dry spun fibers and/or spunbond fibers, staple fibers, hollow fibers, shaped fibers such as multilobal fibers and multicomponent fibers, especially bicomponent fibers. These multicomponent fibers, particularly bicomponent fibers, can be in a side-by-side, sheath-core, segmented pie, ribbon, islands-in-the-sea configuration, or any combination thereof. The sheath may be continuous or discontinuous around the core. The weight ratio of sheath to core may be from about 5: 95 to about 95: 5. The fibers of the present invention can have different geometries including round, oval, star, rectangular and other various eccentricities.

In another embodiment, the hydroxyl polymer-containing fiber can comprise a multicomponent fiber, such as a multicomponent fiber, that comprises the hydroxyl polymer of the present invention in combination with a thermoplastic water-insoluble polymer. As used herein, multicomponent fibers are fibers having more than one spatially separated portion. Multicomponent fibers include bicomponent fibers, which are defined as fibers having two portions that are spaced apart from each other in a spatial relationship. The different components of a multicomponent fiber can be arranged in substantially different regions across the cross-section of the fiber and extend continuously along the length of the fiber.

A non-limiting example of such a multicomponent fiber, in particular a bicomponent fiber, is a bicomponent fiber wherein the hydroxyl polymer serves as the core of the fiber and the thermoplastic water-insoluble polymer serves as a sheath that surrounds or substantially surrounds the core of the fiber. The polymer melt composition from which the above fibers can be made includes a hydroxyl polymer and a thermoplastic water insoluble polymer.

In another multicomponent, especially bicomponent fiber embodiment, the sheath can comprise a hydroxyl polymer and a crosslinking system comprising a crosslinking agent, and the core can comprise a hydroxyl polymer and a crosslinking system comprising a crosslinking agent. The hydroxyl polymer may be the same or different and the crosslinking agent may be the same or different for the sheath and core. Furthermore, the content of the hydroxyl polymer may be the same or different, and the content of the crosslinking agent may be the same or different.

One or more substantially continuous fibers or continuous fibers of the present invention may be incorporated into a fibrous structure, such as a web. The fibrous structures described above can be ultimately incorporated into commercial products, such as single or multi-ply fibrous products, such as facial tissues, bath tissues, paper towels and/or wipes, feminine care products, diapers, writing papers, core materials such as paper cores, and other types of paper products.

The term "layer" or "layers" as used herein refers to an individual fibrous structure, which may optionally be positioned in substantial contiguous, face-to-face relation with other layers to form a multi-layered fibrous product. It is also contemplated that a single fiber structure may be effectively formed into two or more layers by, for example, folding upon itself. The layer or layers may be present as a film or other polymeric structure.

As used herein, "basis weight" is the weight per unit area of the sample, in terms of 1bs/3000ft²Or 1.63g/m²And (6) reporting.

By making with a certain area (m)²) And the basis weight is determined by weighing the fibrous structure sample and/or film according to the present invention on a top-load balance with a minimum resolution of 0.01 g. The balance uses an airflow hood to protect it from airflow and other disturbances. The weight was recorded when the reading on the balance was constant. The average weight (g) and the average area of the sample (m) were calculated²). Dividing the average weight (g) by the average area of the sample (m)²) The quantitative (g/m) was calculated²)。

The term "caliper" as used herein refers to the macroscopic thickness of a fibrous structure, fibrous product, or film. By cutting a sample of the fibrous structure, fibrous product or film to a size larger than the loading foot loading surface, wherein the circular surface area of the loading foot loading surface is about 20.3cm²(3.14in²) To determine the thickness of a fibrous structure, fibrous product or film according to the present invention. The sample is confined between a horizontal plane and the loading foot loading surface. The confining pressure applied to the sample by the loading foot loading surface was 1.45kPa (15.5 g/cm)²(about 0.21 psi)). The resulting gap between the flat surface and the loading surface of the loading foot is the thickness. This measurement was made on a VIR electronic caliper (model II, available from Thwing-Albert Instrument Company, Philadelphia, Mass.). The thickness measurements were repeated and recorded at least five (5) times to calculate the average thickness. The results are reported in millimeters. In one embodiment of the invention, the fibrous structure exhibits an average thickness that is less than its overall thickness.

The term "apparent density" or "density" as used herein refers to the quantitative division of a sample by thickness, using appropriate transformations incorporated herein. Apparent Density as used herein has the unit of g/cm³。

The term "weight average molecular weight" as used herein refers to the weight average molecular weight as determined by gel permeation chromatography according to the protocol found in "Colloids and Surfaces A. Physico chemical & Engineering applications" volume 162 (2000) pages 107 to 121.

The term "plastic" as used herein means that at least the polymeric structure and/or fibrous structure exhibits the ability to be shaped, molded and/or formed.

The term "fibrous product" as used herein includes, but is not limited to, wipes for post-defecation cleaning (toilet tissue), for otorhinolaryngological discharge (facial tissue), and multi-purpose absorbent and cleansing uses (absorbent towels).

As used herein, the terms "lint" and/or "pilling" refer to discrete portions of polymeric structures, particularly fibrous structures and/or fibrous products, which typically separate from the original polymeric structures and/or fibrous products during use.

Conventional toilet paper and paper towels are essentially made of short cellulose fibers. During the wiping process-wet and dry wiping, these short fibers can separate from the structure and become apparent lint or pills. In contrast to conventional discrete short cellulose fibers, the present invention uses substantially continuous fibers. Generally, due to the continuity of the fibers, the fibrous structures of the present invention prevent lint compared to their cellulosic relatives. In addition, the fibrous structures of the present invention can prevent pilling as compared to their cellulosic relatives, provided that during the wiping process the bonding forces and fiber strength and stretch are sufficiently strong to prevent free fiber breakage and adjacent fiber entanglement.

As used herein, the term "strength property" and/or "common strength property value" refers to density, basis weight, thickness, substrate thickness, height, opacity, wrinkle frequency, and any combination thereof. The fibrous structure of the present invention may comprise two or more regions exhibiting values of common strength properties that differ from one another. In other words, the fibrous structure of the present invention may comprise one region having a first opacity value and a second region having a second opacity value, wherein the second opacity value is not used for the first opacity value. The regions may be continuous, substantially continuous, and/or discontinuous.

The terms "dry spinning" and/or "solution spinning" as used herein mean that the polymeric structure is not spun into the bond pot, as opposed to wet spinning.

The term "associated with" as used herein in relation to fibers means that two or more discrete fibers are in close proximity to each other at one or more points along the length of the fibers, but less than their overall length, such that one fiber affects the function of another fiber. Non-limiting examples of methods for associating fibers include bonding together (adhesive and/or chemical and/or electrostatic) and/or fusing together such that a fiber unit is formed upon association.

The term "non-associated" as used herein with respect to fibers means that the fibers do not associate as defined herein.

Method of the invention

The present process relates to making polymeric structures, such as fibers, films, or foams, from non-PVOH polymer melt compositions comprising hydroxyl polymers, and/or to making fibrous structures comprised of polymeric structures in the form of fibers.

As described below, in one non-limiting embodiment of the process according to the present invention, the non-PVOH polymer melt composition is subjected to polymer processing to form fibers. The fibers are then incorporated into a fibrous structure.

Any suitable method known to those skilled in the art may be used to make the polymer melt composition, and/or the polymer processes the polymer melt composition and/or polymeric structure of the present invention. Non-limiting examples of the above methods are described in published applications: EP 1035239, EP 1132427, EP 1217106, EP 1217107 and WO 03/066942.

A. non-PVOH polymer melt compositions

As used herein, the term "non-PVOH polymer melt composition" refers to compositions comprising melt-processed hydroxyl polymers. As used herein, "melt-processed hydroxyl polymer" refers to any polymer other than polyvinyl alcohol that contains greater than 10% and/or greater than 20% and/or greater than 25% hydroxyl groups by weight and is melt-processed with the aid of an external plasticizer and/or with the aid of a pH adjuster. More generally, melt-processed hydroxyl polymers include polymers that soften to a fluid state (all melt processing operations/processes) under the influence of high temperature, pressure and/or external plasticizers and that can be shaped as desired in this state.

The non-PVOH polymer melt composition can be a composition comprising a blend of different polymers, at least one of which is a melt-processed hydroxyl polymer according to the invention, and/or inorganic and organic fillers, and/or fibers, and/or blowing agents. In one embodiment, the non-PVOH polymer melt composition comprises two or more different hydroxyl polymers melt-processed in accordance with the present invention. The term "melt-processed dissimilar hydroxyl polymer" as used herein includes, but is not limited to, a melt-processed hydroxyl polymer comprising at least one distinct moiety as compared to another melt-processed hydroxyl polymer; and/or melt-processed hydroxyl polymers belonging to different chemical classes (e.g., starch and chitosan).

The non-PVOH polymer melt composition may have been formed, or a melt processing step may be required to convert the starting hydroxyl polymer into a melt processed hydroxyl polymer, thereby forming a non-PVOH polymer melt composition. Any suitable melt processing step known in the art can be used to convert the starting hydroxyl polymer into a melt processed hydroxyl polymer.

The non-PVOH polymer melt composition can comprise: a) from about 30% and/or 40% and/or 45% and/or 50% to about 75% and/or 80% and/or 85% and/or 90% and/or 99.5% of hydroxyl polymer, by weight of the non-PVOH polymer melt composition; b) a crosslinking system comprising about 0.1% to about 10% of a crosslinking agent, by weight of the non-PVOH polymer melt composition; and c) from about 0% and/or 10% and/or 15% and/or 20% to about 50% and/or 55% and/or 60% and/or 70% of an external plasticizer (e.g., water), by weight of the non-PVOH polymer melt composition.

B. Polymer processing

As used herein, the term "polymer processing" refers to any operation and/or process of forming a polymeric structure comprising a processed hydroxyl polymer via a non-PVOH polymer melt composition. Non-limiting examples of polymer processing operations include extrusion, molding, and/or fiber spinning. Extrusion and molding (casting or blowing) are typically done to produce films, sheets, and extrusions of various shapes. The molding may include injection molding, blow molding, and/or compression molding. Fiber spinning may include spunbond, meltblown, continuous fiber making, and/or tow fiber making.

The term "processed hydroxyl polymer" as used herein refers to any hydroxyl polymer that has been subjected to a melt processing operation and subsequent polymer processing operation.

C. Polymer structure

The non-PVOH polymer melt composition can be subjected to one or more polymer processing operations such that the non-PVOH polymer melt composition is processed into a polymeric structure, such as a fiber, film, or foam, that includes a hydroxyl polymer and a crosslinking system according to the present invention.

Post-treatment of polymeric structures

After the non-PVOH polymer melt composition is processed into a polymeric structure (e.g., a fiber, film, foam, or plurality of fibers that collectively form a fibrous structure), the structure can be subjected to post-treatment curing and/or differential compaction.

The curing of the structure may be performed before and/or after the consolidation of the structure region. Preferably, curing is carried out before the region of the structure is compacted.

In one embodiment, the formed structure is cured by a polymer processing operation at a curing temperature of from about 110 ℃ to about 200 ℃, and/or from about 120 ℃ to about 195 ℃, and/or from about 130 ℃ to about 185 ℃, for about 0.01 seconds, and/or 1 second, and/or 5 seconds, and/or 15 seconds to about 60 minutes, and/or from about 20 seconds to about 45 minutes, and/or from about 30 seconds to about 30 minutes, prior to compacting the structure region. Alternative curing methods may include radiation methods such as UV, electron beam, IR and other temperature-raising methods.

Furthermore, the structure may also be cured at room temperature for several days, after or without curing at the above-mentioned temperatures.

The structure prior to being consolidated may comprise substantially continuous or continuous non-associated fibers comprising hydroxyl polymers. In addition, the substantially continuous or continuous fibers may comprise crosslinked hydroxyl polymers. The structure may even further comprise from about 10% and/or from about 15% and/or from about 20% to about 60% and/or to about 50% and/or to about 40% moisture, by weight of the structure.

Prior to differential compaction, the structure may be in the form of a non-associated structure, particularly when the structure comprises one or more fibers. The structures in the above-described undifferentiated compacted form have poor strength properties, especially extensibility (stretchability), compared to their wood-based cellulosic fibrous structure relatives.

Thus, the structures of the present invention may be differentially compacted via differential compaction operations. The differential compaction described above may be performed in-line in a continuous process that includes forming a structure and then differentially compacting the structure. Alternatively, the differential compaction may be performed off-line in a non-continuous process.

Any differential compaction method known to those of ordinary skill in the art may be used to differentially compact the structures of the present invention.

As a result of differential compaction, the structure includes two or more regions that appear to have different densities when compared to other regions.

In one embodiment, the differential compaction method includes the step of imparting plasticity to the structure requiring differential compaction such that regions of different densities are created in the structure. In other words, the differential compaction method includes the step of imparting plasticity to the structure requiring differential compaction such that a pattern is created in the structure. The pattern is intended to create regions of different density in the structure. Placing a structure requiring differential compaction in a humid environment having a relative humidity of, for example, from about 20% to about 95%, and/or from about 40% to about 90%, and/or from about 50% to about 85%, and/or from about 65% to about 80%, for a sufficient time, such as at least 1 second and/or at least 3 seconds and/or at least 5 seconds, can impart sufficient plasticity to the structure such that differential compaction is caused in the structure.

In one embodiment, the differential compaction process includes passing the structure through a patterned roll such that the pattern on the roll is imparted onto the structure, thereby causing the structure to become differentially compacted.

In another embodiment, the differential compaction process comprises contacting the structure in contact with the patterned belt/fabric with pressure from a smooth roll, thereby transferring the pattern of the belt/fabric to the structure and causing the structure to become differentially compacted.

Differential compaction of structures according to the present invention is performed after, and not simultaneously with, formation of the structure.

The structure of the present invention may be differentially compacted more than once. For example, in accordance with the present invention, the structure may be differentially densified, then cured, and then differentially densified again.

In another embodiment, the structure may comprise a structure of two or more "plies", which may then be differentially consolidated as a multi-layer structure.

The structure may be differentially compacted and then differentially compacted again and then cured.

Alternatively, the structures of the present invention may be cured and then differentially densified in accordance with the present invention.

In accordance with the present invention, curing of the structure may be performed at any point in time relative to any differential compaction process. May be performed before (preferably immediately before), after (preferably immediately after), before and after (preferably immediately before and after), or not at all.

The differential compaction process may be performed one or more times.

Ultrasonic welding may also be used to assist in differentially compacting the structure, particularly when used in conjunction with patterned rolls. The ultrasonic weld may be formed by any suitable ultrasonic means. For example, a horn or sonotrode capable of imparting energy to the structure to deform the structure according to the pattern on the patterned roll may be used.

In another embodiment, the step of differentially compacting comprises: in the presence of moisture, contacting the fibrous structure with a structure imparting element comprising a pattern and applying a force to the fibrous structure and/or the structure imparting element such that the fibrous structure acquires the shape of the pattern on the structure imparting element to form a differentially compacted polymeric structure.

In another embodiment, the step of differentially densifying the fibrous structure comprises: the method includes the steps of sandwiching a fibrous structure between two belts in the presence of moisture, wherein at least one belt is a structured belt that includes a pattern, and then applying a force to the at least one belt such that the fibrous structure acquires the shape of the pattern on the structured belt to form a differentially densified polymeric structure.

The following provides non-limiting examples of differential compaction processes for differentially compacted structures according to the present invention.

Examples of differential compaction

A non-PVOH polymer melt composition comprising about 40% water was extruded from a twin screw extruder. The crosslinker and other additives are added to the melt and stirred by an in-line static mixer. The non-PVOH polymer melt composition containing the additives is then pumped to a meltblowing nozzle where the fibers are pressed and attenuated to fine fibers. One suitable hydroxyl polymer is starch available from Penford Products Inc. under the trade name Penfilm 162. The crosslinkers and additives used are urea glyoxal adduct ("UGA"), ammonium sulfate and acrylic latex. The content of all additives is typically 10% or less, in weight percent on a dry basis of the hydroxyl polymer. The attenuated fibers are dried with the hot air being drawn and deposited on a collection belt. The collection belt is typically positioned 55.9 to 63.5cm (22-25 ") from the spinneret tip and the resulting structure, the fiber structure, on the collection belt is a non-associated fiber structure.

FIG. 1 diagrammatically illustrates one embodiment of a differential compaction operation 10. After the non-associated fibrous structure 12 is formed, it is placed in an environmentally controlled, moist environment, such as a moisture box 14. Typical relative humidity ranges are 70% to 78%. Fine starch when fibrous structure 12 is delivered through chamber 14The fibers are plasticized and differential compaction is possible. Upon exiting chamber 14, the plasticized fibrous structure 12' is passed through a pattern nip 16 to associate regions of the fibrous structure to form an associated fibrous structure 12 ". The associated fibrous structure region 18 conforms to a pattern used on a moving belt (not shown) or the roll itself 20. One pattern strip used is a square woven apertured strip, available from Albany International Inc. and known as "Filtratech 10" type. The nip pressure varies depending on the pattern used, but is typically in the range of 200-300 pli. The fibers contained in current fibrous structures are associated and the fibrous structures exhibit superior performance properties. After the curing stage of the crosslinking system and additive development reaction, the associated fibrous structure exhibits acceptable dry and wet properties for disposable fibrous products and is useful as a variety of disposable devices, particularly toilet tissue or paper towels. The following table summarizes one embodiment of a fibrous structure according to the present invention under different conditions (i.e., pre-differential compaction, post-differential compaction, and post-differential compaction curing) with a typical commercial tissue (e.g., Charmin)^®1-ply) of the composition.

	Precompaction	Post-compaction	Post-compaction curing	Typical tissue paper (Charmin)®1-layer slice)
					Dry MD + CD tensile g/cm (g/in)	55.9(142)	115.4(293)	173.6(441)	157.5(400)
Dry destructive stretching%	29	16	18	25
					Dry break g	80	92	261	150
Dry breaking energy g/cm	0.5	0.47	1.5	1.7
					Basis weight g/m2	36	36	36	36

Hydroxyl polymer

Hydroxyl polymers according to the present invention include any hydroxyl containing polymer other than polyvinyl alcohol that can be incorporated into the polymeric structures of the present invention, preferably in the form of fibers.

In one embodiment, the hydroxyl polymer of the present invention comprises greater than 10% and/or greater than 20% and/or greater than 25% by weight hydroxyl moieties.

Non-limiting examples of hydroxyl polymers according to the present invention include polyols such as starch, starch derivatives, chitosan derivatives, cellulose derivatives such as cellulose ether and cellulose ester derivatives, gums, arabinans, galactans, proteins and various other polysaccharides, and mixtures thereof.

The hydroxyl polymer preferably has a weight average molecular weight of from about 10,000 to about 40,000,000 g/mol. Higher and lower molecular weight hydroxyl polymers can be used in combination with hydroxyl polymers having the preferred weight average molecular weight.

Well known modifications of native starch include chemical and/or enzymatic modifications. For example, native starch may be acid thinned, hydroxyethylated or hydroxypropylated or oxidized.

By "polysaccharide" herein is meant natural polysaccharides and polysaccharide derivatives or modified polysaccharides. Suitable polysaccharides include, but are not limited to, gums, arabinans, galactans, and mixtures thereof.

Cross-linking system

In addition to the crosslinking agent, the crosslinking system of the present invention may also comprise a crosslinking accelerator.

The term "crosslinking facilitator" as used herein refers to any substance capable of activating a crosslinking agent to thereby transition the crosslinking agent from its unactivated state to its activated state. In other words, the hydroxyl polymers present in the non-PVOH polymer melt composition do not prematurely crosslink ("unacceptable" crosslinking) when the crosslinker is in its unactivated state, as determined by the shear viscosity change test method described herein.

When the cross-linking agent according to the present invention is in its activated state, the hydroxyl polymer present in the polymeric structure may (and preferably does) undergo acceptable cross-linking by the cross-linking agent as determined according to the "initial total wet tensile test method" described herein.

The crosslinking facilitator may include derivatives of the material that may be present after conversion/activation of the crosslinking agent. For example, the crosslinking promoter salt is chemically converted to its acid salt and vice versa.

The crosslinking system can be present in the non-PVOH polymer melt composition and/or can be added to the non-PVOH polymer melt composition prior to polymer processing of the non-PVOH polymer melt composition.

Non-limiting examples of suitable crosslinking promoters include acids, or salts thereof, having a pKa of from about 0 to about 6, and/or from about 1.5 to about 6, and/or from about 2 to about 6. The crosslinking facilitator may be a Bronsted acid and/or a salt thereof, preferably an ammonium salt thereof.

In addition, metal salts, such as magnesium and zinc salts, can be used as crosslinking promoters alone or in combination with Bronsted acids and/or their salts.

Non-limiting examples of suitable crosslinking facilitators include acetic acid, benzoic acid, citric acid, formic acid, glycolic acid, lactic acid, maleic acid, phthalic acid, phosphoric acid, sulfuric acid, succinic acid, and mixtures thereof and/or salts thereof, preferably ammonium salts thereof, such as ammonium glycolate, ammonium citrate and ammonium sulfate.

Non-limiting examples of suitable crosslinking agents include polycarboxylic acids, imidazolidinone, and other compounds derived from alkyl substituted or unsubstituted cyclic adducts of glyoxal with urea, thiourea, guanidine, methylene diamide and methylene dicarbonate and their derivatives, and mixtures thereof.

Test method

All tests described herein include those described in the definitions section, and the following test methods were performed on samples conditioned for 24 hours prior to testing in a conditioning chamber having a temperature of about 23 ℃ ± 2.2 ℃ (73 ° f ± 4 ° f) and a relative humidity of about 50% ± 10%. Furthermore, all tests were performed in a conditioning chamber. Prior to image capture, the samples and felts tested should be allowed to stand at about 23 ℃. + -. 2.2 ℃ (73 ℃. + -. 4F) and 50%. + -. 10% relative humidity for 24 hours.

A. Cotton wool/pilling test method

i. Sample preparation

Prior to testing, a sample of fibrous product, a 11.4cm by 40.6cm (4.5 "by 16") strip of fibrous product, was conditioned according to Tappi Method # T402 OM-88.

Each fiber product sample is first prepared by removing and discarding any sample portions that may have been worn away during processing (6 samples if double-sided, 3 samples if single-sided). For fibrous products formed from a multi-ply fibrous structure, such tests can be used to perform lint measurements on a multi-ply fibrous product, or if the plies can be separated without damaging the sample, measurements can be made on the individual plies that make up the fibrous product. If the surfaces of a given sample are different from each other, both surfaces must be tested and the values averaged to obtain a combined lint value. Sometimes, the fibre product is made of a multi-ply fibre structure with the same outer surface, in which case only one surface needs to be tested.

Each sample was folded onto itself to make a 11.4cm CD by 10.2cm MD (4.5 "CD by 4" MD) sample. For the two-sided test, 3 (11.4cm CD × 10.2cm MD (4.5 "CD × 4" MD)) samples with the first surface "facing outward" and 3 (11.4cm CD × 10.2cm MD (4.5 "CD × 4" MD)) samples with the second surface "facing outward" were made. Note which samples are the first surface "out" and which samples are the second surface "out".

Crescent #300 paperboard was obtained from Cordage Inc. (800 E.Ross Road, Cincinnati, Ohio, 45217) at 76.2cm x 101.6cm (30 "x 40"). Six sheets of paperboard were cut with a paper cutter to 6.4cm by 15.2cm (2.5 "by 6"). Two holes were punched in each of the six sheets of cardboard by pressing the board hard on the fixing pins of the Sutherland friction tester.

Each paperboard was carefully centered over six (double-sided test) or three (single-sided test) samples that had already been folded. The 15.2cm (6 ") dimension of the paperboard was ensured to be parallel to the Machine Direction (MD) of each sample.

One edge of the exposed portion of the sample was folded behind the cardboard. This edge was secured to the cardboard using tape from 3M Inc. (1.9cm (3/4 ") wide Scotch Brand, St. Paul, Minn.). Carefully grasp the other protruding tissue edge and fold it neatly behind the cardboard. The second edge of the sample was taped to the back of the cardboard while keeping the sample in close proximity to the cardboard. This procedure was repeated for each sample.

Each sample was turned over and taped to the cardboard crosswise to the edges for dry lint/pilling testing. One half of the tape should contact the sample while the other half is glued to the cardboard. This procedure was repeated for each sample. If at any time during the specimen preparation process the specimen breaks, tears or wears, it is discarded and a new specimen is made from the sample strip.

For the wet lint/pill test, the front cross-directional edge of the sample was taped to a cardboard and table top with the sample on top. The sample was secured to the cardboard such that the back edge of the sample was about 0.6cm (1/4 ") from the edge of the cardboard. The front edge of the sample was taped to the cardboard and the table top to secure the opposite (back) edge of the cardboard to the table top edge.

Now, there will be 3 samples with the first surface "outward" on the paperboard and (optionally) 3 samples with the second surface "outward" on the paperboard.

Manufacture of felt

Crescent #300 paperboard was obtained from Cordage Inc. (800 E.Ross Road, Cincinnati, Ohio, 45217) at 76.2cm x 101.6cm (30 "x 40"). Six sheets of paperboard were cut with a paper cutter to 5.7cm by 18.4cm (2.25 "by 7.25"). Two lines were drawn parallel to the short dimension and 2.9cm (1.125 ") from the top and bottom largest edges on the white side of the paperboard. The length of the line is carefully scribed with a blade using a straight edge as a guide. To a depth of about half the thickness of the entire sheet. This scoring allows the felt/cardboard combination to fit tightly around the weight of the sutherland Rub tester. An arrow is drawn on this scored side of the sheet extending parallel to the long dimension of the sheet.

Six black mats (F-55 or equivalent, New England Gasket, 06010, 550Broad Street, Bristol, Conn.) were cut out in sizes of 5.7cm by 21.6cm by 0.159cm (2.25 "by 8.5" by 0.0625 "). The felt was placed on top of the unpainted green side of the cardboard so that the long edges of both the felt and the cardboard were parallel and in line. The black felt was also allowed to protrude about 1.3cm (0.5 ") beyond the top and bottom largest edges of the cardboard. The overhanging two felt edges were folded snugly against the cardboard back using Scotch brand tape, alternatively the felt could be made to fit tightly against the cardboard when the felt/cardboard combination was glued to the weight described below. A total of six felt/paperboard compositions were made.

For the wet lint/pilling test, the felt/cardboard combination included a 22.9cm (9 ") Scotch brand tape strip (1.9cm (0.75") wide) placed on the face of the felt that will contact the sample along each edge of the felt (parallel to the long side of the felt). The non-attached felt located between the two tape strips has a width of 18 to 21 mm. Three markers were placed at 0, 4 and 8cm from the rear edge of the felt on one tape strip.

All samples must be made using the same batch of felt.

Felt/cardboard/weight assembly

The felt/cardboard combination is combined with a weight. The weight may include a clamping device to attach the felt/cardboard combination to the weight. The weight and all clamping devices combined together weighed 2.6kg (five (5) pounds). Weights are available from Danilee Company, San Antonio, TX. The weight has an effective contact area of 25.81cm²(4in²) And may provide a contact pressure of about 8.62kPa (1.25 psi).

Performing a dry pill/pill test

The amount of dry lint and/or dry pilling produced by the fibrous product according to the invention was determined using a Sutherland friction tester (available from Danilee Company, san antonio, TX). The tester rubs the felt/cardboard/weight assembly 5 times (back and forth) on the fibrous product using a motor while the fibrous product is restrained in a fixed position. The gray value of the felt was measured before and after the friction test. The difference between these two gray values is then used to calculate a dry lint value and/or a dry pill value.

The Sutherland friction tester must first be calibrated before use. First, press the "reset" button, start the Sutherland friction tester. At the lower two speeds, the tester was run for 5 strokes. One stroke is one and full forward and reverse movement of the weight. At the beginning and end of each test, the end of the pad should be at the nearest position to the operator.

As described above, a standard sample was prepared on a cardboard sample. Further, as described above, a standard felt was prepared on the cardboard sample. These two standard preparations will be used for calibration of the instrument and will not be used for collecting data of actual samples.

The standard sample/cardboard combination is placed on the tester floor by sliding the holes in the cardboard onto the fixing pins. The retaining pin prevents the sample from moving during testing. A standard felt/cardboard sample was clamped to the weight assembly described above while the cardboard side was in contact with the weight pads. Ensuring that the standard felt/cardboard combination is flat against the weight. The weight was hung on the test arm of a Sutherland friction tester and gently placed over the standard sample/cardboard combination. The standard felt must be horizontally positioned on the standard sample and must be 100% in contact with the standard sample surface. Pressing the "on" button starts the Sutherland friction tester.

The number of strokes was recorded and the beginning and end positions of the weight against the standard felt relative to the standard sample were observed and noted. If the total number of strokes is five, and if the end position of the weight against the standard felt is the same as at the beginning of the test, the tester is calibrated and ready for use. If the total number of strokes is not five, or if the starting and ending positions of the weight against the standard felt are different, the instrument needs to be repaired and/or recalibrated. During the actual testing of the samples, the number of strokes and the beginning and end of the weight against the standard felt were monitored and observed.

v. carrying out the Wet lint/pilling test

Wet lint/pilling was determined by pulling a wet felt/cardboard/weight assembly over the specimen in one pass.

To wet the felt, 0.6mL of deionized water was drawn up the felt, distributing the water as evenly as possible between the 4 to 8cm mark shown on the tape to which the felt was affixed. Wait 10 seconds and then place the felt/cardboard/weight assembly in the center of the sample. After 1 second, the felt/cardboard/weight assembly was pulled horizontally along the front edge until the felt/cardboard/weight assembly was completely off the table. The weight is pulled in a manner to avoid exerting any other force than a horizontal pulling force on the felt/cardboard/weight assembly. The process of pulling the felt/cardboard/weight assembly takes about 0.5 to 1.5 seconds. The pulling process should be performed in a substantially continuous or continuous motion.

The felt/cardboard combination is carefully removed from the felt/cardboard/weight assembly and allowed to dry before the image is taken. Image analysis operations are then performed, as described below, and calculations are performed on the felt and/or sample.

Image capture

Images of felt (not tested), sample (not tested) and felt (tested) were taken using a Nikon digital camera (DIX) equipped with a Nikon Nikkor 24-85mm F2.8-F4D 1F AF lens set at 85mm maximum magnification and Nikon Capture software installed on a suitable computer. As illustrated diagrammatically in FIG. 2, a Kodak Camera cradle/illuminator (not shown) is attached to the Camera 22, the illuminator having four incandescent lamps 24 (polarized MP-4 Land Camera, model 44-22, 150 Watts each at 120 volts) aimed at a felt 26 located 31cm (12.2 inches) below the mounted Camera lens. The spacing between each incandescent lamp 24 was 27.94cm (11 inches). The incandescent lamps 24 of each pair are spaced 88.9cm (35 inches) apart. The incandescent lamp 24 was placed 56.83cm (223/8 inches) above the felt 26. The camera is connected to the computer by a suitable cable. The camera should be turned on to PC mode. The button is rotated to the camera lens at high magnification and the switch is moved to the lens base orange mark. The magnification was adjusted to 85mm at its maximum level. The auto focus function is turned off. The Nikon Capture software needs to operate to Capture images. The settings of the Nikon Capture software are as follows: exposure 1-manual exposure mode, shutter speed 1/30 seconds, f/6.3 aperture and OEV exposure compensation; exposure 2-central focus measurement mode, ISO 125 sensitivity and incandescent white balance; storage set-raw (12 bit) data format, no compression, color pattern and large (3008 × 1960) image size; mechanical operation-single shot mode, single scene AF scene mode, manual focus mode. A standard felt/cardboard combination was placed under the camera with the felt centered under the camera lens. The camera was manually focused on the felt. An image is captured. The difference in exposure needs to be in the range of +2.5 to + 2.75. The image is saved as TIFF file (RGB)8 bits. This image was used to perform lint and pilling calculations in the image analysis software (Optimas 6.5). Other images of the sample/cardboard combination (untested) and the felt/cardboard combination (tested) need to be taken in the same manner. Also, an image of a standard (e.g., a ruler) of known length is taken (exposure differences do not affect the image).

Image analysis

The captured images were analyzed using Optimas 6.5 image analysis software commercially available from Media Cybernetics (l.p.). The imaging setup parameters as set forth herein must be followed exactly to obtain meaningful comparable lint and pilling value results.

First, an image of a known length standard (e.g., a ruler) is called up in Optimas and used to calibrate length units (in this case, millimeters).

For the dry test, the felt image tested had a region of interest (ROI area) of about 4510mm2(82mm by 55 mm). The exact ROI area (variable name: ROI area) was determined and recorded.

For the wet lint/pilling test, the tested felt image has 2 regions of interest (ROI areas):

1) a "wet" zone (between tape 4 to 8cm mark) and 2 "pull" zone (between tape 0 to 4cm mark). Each ROI area was about 608mm2(38mm by 16 mm). The exact ROI area (variable name: ROI area) was determined and recorded.

The untested black felt image was opened and then the average gray value was determined (untested felt used the same ROI as the tested felt) and recorded (variable name: gray average of untested felt).

The measured sample luminance is saturated white (gray value 255) and is constant for the sample of interest. If the difference is deemed, the sample tested is tested in a similar manner as the test for the untested felt and recorded (variable name: grey scale average of untested sample).

The brightness threshold was calculated as the numerical average of the gray scale average of the untested felt and the gray scale average of the untested sample.

The felt image being tested is opened, the ROI is generated and placed appropriately so that the ROI surrounds the felt image area being tested that is to be analyzed. The average brightness of the ROI (variable name: ROI grayscale average) was recorded.

Pilling assay was as follows: optimas produces a boundary line in the image where pixel intensity values cross the threshold (e.g., if the threshold for gray values is 155, a boundary line is produced on either side with higher and lower pixel values). The criteria for determining pilling are that it must have an average brightness greater than a threshold value and a perimeter length greater than 2mm for dry pilling and greater than 0.5mm for wet pilling. The areas where pilling occurred in the ROI are summed (variable name: total pilling area).

viii. calculation

The data obtained from the image analysis were used for the following calculations:

total area of lift-off area%

Average pilling size (area weighted average, mm)²) Sigma (spherical area)²Total area of lift

Lint value-average of the gray level of untested felt-average of the gray level of untested felt

In the formula: average value of gray scale of unsettled felt [ [ (ROI average value of gray scale × ROI area) - (average value of gray scale of unsettled felt × [ spherical area) ]/total unsettled area

Total area lint and pilling value ROI Gray average-Gray average of untested felt

By averaging the lint values on the first and second side surfaces, a lint value is obtained that is applicable to the particular web or article. In other words, the lint value is calculated using the following formula:

B. method for measuring and testing shear viscosity of polymer melt composition

The shear viscosity of the polymer melt compositions of the present invention was determined using a capillary rheometer Goettfert Rheograph 6000, manufactured by Goettfert USA, Rock Hill SC, USA. The measurements were made using a capillary die having a diameter D of 1.0mm and a length L of 30mm (i.e., L/D-30). The die was attached to the lower end of a 20mm cylinder of a rheometer, which was held at a die test temperature of 75 ℃. A 60g sample of the polymer melt composition, which had been preheated to the mold test temperature, was added to the barrel portion of the rheometer. All entrained air was removed from the sample. At a selected set of rates 1,000 to 10,000sec^-1The sample is pushed from the cylinder through the capillary die. The rheometer software can use the pressure drop of the sample from the cylinder to the capillary die and the flow rate of the sample through the capillary die to calculate the apparent shear viscosity. The log (apparent shear viscosity) versus log (shear rate) can be plotted, for example, by the formula η ═ K γ^n-1Where k is the viscosity constant of the material, n is the thinning index of the material, and γ is the shear rate. The reported apparent shear viscosity of the compositions herein is interpolated to a shear rate of 3,000sec using a power law relationship^-1The time is calculated.

C. Shear viscosity change testing method

The viscosities of three samples of a single polymer melt composition of the present invention containing a crosslinking system to be tested were determined by filling three separate 60cc syringes; the shear viscosity (initial shear viscosity) of a sample is measured immediately (about 10 minutes from the first reading of the sample placed in the rheometer) according to the test method for determining the shear viscosity of a polymer melt composition. If the shear rate is 3,000sec^-1When the initial shear viscosity of the first sample is not in the range of 5 to 8Pascal. sec, then the single polymer melt composition must be adjusted so that it is at a shear rate of 3,000sec^-1When measured under the conditions of (a), the initial composition of the single polymer meltThe initial shear viscosity was in the range of 5 to 8pascal. Once at a shear rate of 3,000sec^-1When measured under conditions of (a) the initial shear viscosity of the polymer melt composition is in the range of 5 to 8 Pascal-seconds, then the same test method is used after the other two samples are stored in a convection oven at 80 ℃ for 70 and 130 minutes, respectively. Samples at 3000sec for 70 and 130 minutes^-1The shear viscosity at (b) is divided by the initial shear viscosity to give the normalized shear viscosity change for the 70 and 130 minute samples. If the normalized shear viscosity change is 1.3-fold or greater after 70 minutes and/or 2-fold or greater after 130 minutes, then the crosslinking system in the polymer melt composition is unacceptable and, therefore, outside the scope of the present invention. However, if the normalized shear viscosity change is less than 1.3 times after 70 minutes and/or (preferably and) less than 2 times after 130 minutes, then the crosslinking system is satisfactory and is therefore within the scope of the present invention for polymer melt compositions comprising the crosslinking system. Preferably, the crosslinking system is satisfactory for the polymer structure obtained from the polymer melt composition comprising the crosslinking system as determined by the initial Total Wet tensile test method.

Preferably, the normalized shear viscosity change will be less than 1.2 times after 70 minutes, and/or will be less than 1.7 times after 130 minutes; more preferably less than 1.1 times after 70 minutes and/or less than 1.4 times after 130 minutes.

D. Initial total wet tension test method

An electronic tensile Tester (Thwing-Albert EJA Materials Tester, Thwing-Albert Instrument co., 10960 Dutton Rd., philidelphia, Pa., 19154) was used and operated at a crosshead speed of about 10.16cm (4.0 inches) per minute and a gauge length of about 2.54cm (1.0 inches), using 2.54cm (1 inch) wide and more than 7.62cm (3 inches) long strips of the polymer structure. The ends of the strip were placed in the upper clamp of the machine and then the centre of the strip was placed around a stainless steel nail (0.5 cm diameter). After confirming that the strip was bent evenly around the steel nail, the strip was soaked in distilled water at about 20 ℃ for 5 seconds before starting the crosshead motion. The initial results of the test are a list of data in terms of load (grams force) versus crosshead displacement (centimeters from the starting point).

The samples were tested in two directions, referred to herein as MD (machine direction, i.e., the same direction as the continuous winding axis and forming fabric) and CD (cross direction, i.e., 90 from MD). MD and CD wet tensile were measured using the above equipment and calculated as follows:

initial total wet tension ITWT (g)_fIn ═ peak load MD (g)_f) /2 (inches)_{Width of}) + Peak load_CD(g_f) /2 (inches)_{Width of})

The initial total wet tension values were then normalized by the quantification of the strip tested. The normalized amount used was 36g/m²Then, the following calculation is performed:

normalized { ITWT } - [ 36 (g/m) }²) Basis weight of the strip (g/m)²)

A crosslinked system is acceptable if the initial total wet tensile of a polymeric structure, particularly a fibrous structure and/or fibrous product comprising a polymeric structure comprising the crosslinked system of the present invention, is at least 3g/2.54cm (3g/in) and/or at least 4g/2.54cm (4g/in) and/or at least 5g/2.54cm (5g/in), and is within the scope of the present invention along with its corresponding polymeric structure and/or fibrous product.

Fiber diameter testing method

A polymer structure containing a suitable basis weight (about 5 to 20 grams per square meter) of fibers was cut into a rectangle of about 20mm x 35 mm. The samples were then gold plated using a SEM sputter coater (EMS Inc, PA, USA) to make the fibers relatively opaque. Typical coating thicknesses are between 50 and 250 nm. The sample was then held between two standard microscope slides and pressed together with a small binding clip. Images of the samples were obtained using a 10X objective of an Olympus BHS microscope with the microscope light collimating lens as far away from the objective as possible. Images were captured with a Nikon D1 digital camera. The spatial distance of the image was calibrated using a glass microscope micrometer. The approximate resolution of the image is 1 μm/pixel. Typically, the image will show a distinct bimodal distribution on the intensity histogram corresponding to the fibers and background. Camera adjustments or different quantifications are used to obtain an acceptable bimodal distribution. Typically, 10 images are taken per sample and the image analysis results are then averaged.

The images were analyzed by a method similar to that described in B.Pourdeyhimi, R.and R.Dent, Measuring fiber diameter distribution in nowcovers (Textile Res.J.69(4)233-236, 1999). Digital images were analyzed with a computer using MATLAB (version 6.3) and MATLAB image processing toolkit (version 3). The image is first converted to grayscale. The image is then binarized into black and white pixels using a threshold that minimizes the combined variance of the thresholded black and white pixels. Once the image is binarized, the image is skeletonized to determine the location of each fiber center in the image. The distance transform of the binarized image is also calculated. The scalar product of the skeletonized image and the distance map provides an image with zero pixel intensity or a range of fibers at that location. A pixel within the range of an intersection of two overlapping fibers is not counted if it represents a distance less than the intersection radius. The remaining pixels are then used to calculate a fiber diameter length weighted histogram contained in the image.

All documents cited in the detailed description of the invention are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention.

While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.

Claims (12)

1. A polymeric structure comprising a non-PVOH processed hydroxyl polymer composition comprising a hydroxyl polymer, wherein the polymeric structure exhibits a stretch at peak load of at least 5% and/or a stretch at failure load of at least 10%.

2. The polymeric structure of claim 1 wherein said hydroxyl polymer is selected from the group consisting of starch, starch derivatives, chitosan derivatives, cellulose derivatives, gums, arabinans, galactans, proteins, and mixtures thereof, preferably wherein said hydroxyl polymer comprises starch and/or starch derivatives.

3. The polymeric structure according to any of the preceding claims wherein the non-PVOH processed hydroxyl polymer composition further comprises a crosslinking system comprising a crosslinking agent, wherein the hydroxyl polymer is crosslinked by the crosslinking agent such that the polymeric structure as a whole does not exhibit a melting point.

4. The polymeric structure according to any of the preceding claims wherein the polymeric structure is in a form selected from the group consisting of fibers, films and foams, preferably in the form of fibers, more preferably in the form of fibers exhibiting a fiber diameter of less than 50 μm.

5. Use of a polymeric structure in the form of fibers according to claim 4 in a fibrous structure, wherein the fibrous structure exhibits a stretch at peak load of at least 5% and a stretch at failure load of at least 10%, preferably wherein the fibrous structure comprises two or more fibers that are associated with each other, more preferably wherein the fibrous structure comprises two or more regions that exhibit values of common strength properties that differ from each other, most preferably wherein the common strength properties are selected from the group consisting of: density, basis weight, thickness, substrate thickness, height, opacity, crepe frequency, and combinations thereof.

6. Use of a polymeric structure according to claim 4 in a fibrous structure, wherein the fibrous structure comprises a first region comprising associated fibers and a second region comprising non-associated fibers.

7. A method for making the polymeric structure of any one of claims 1 to 4, the method comprising the steps of:

a. providing a non-PVOH polymer melt composition comprising a hydroxyl polymer; and

b. polymer processing the non-PVOH polymer melt composition to form a polymeric structure in the form of a fiber; and

c. optionally, incorporating the polymeric structure in fiber form into a fiber structure;

wherein the fibrous structure exhibits a stretch at peak load of at least 5% and/or a stretch at failure load of at least 10%.

8. The method of claim 7, wherein the method further comprises the step of differentially compacting the fibrous structure such that two or more regions exhibit different densities from one another.

9. The method of claim 8, wherein the step of differentially compacting comprises: contacting the fibrous structure with a structure imparting element comprising a pattern in the presence of moisture and applying a force to the fibrous structure and/or structure imparting element such that the fibrous structure acquires the shape of the pattern on the structure imparting element to form a differentially compacted polymeric structure.

10. The method of claim 8, wherein the step of differentially densifying the fibrous structure comprises: sandwiching the fibrous structure between two belts in the presence of moisture, wherein at least one of the belts is a structured belt comprising a pattern, and then applying a force to at least one of the belts such that the fibrous structure acquires the shape of the pattern on the structured belt to form a differentially compacted polymeric structure.

11. The method of claim 7, wherein the fibrous structure comprises a crosslinking system comprising a crosslinking agent capable of crosslinking the hydroxyl polymer such that the polymeric structure in the form of fibers as a whole does not exhibit a melting point, preferably wherein the method further comprises the step of curing the crosslinking agent.

12. A method for making the polymeric structure of any one of claims 1 to 4, the method comprising the steps of:

a. providing a fibrous structure comprising two or more fibers, wherein at least one of said fibers comprises a polymeric structure in the form of a fiber; and

b. optionally, two or more fibers are associated with each other such that a fibrous structure is formed comprising a first region comprising associated fibers and a second region comprising unassociated fibers.