RU2824131C1 - Water-soluble nonwoven fabrics for packing aggressive chemicals - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: present invention relates to a water-soluble nonwoven fabric and related compositions, specifically to a water-soluble nonwoven fabric for packaging aggressive chemical compositions. Disclosed is an article with a single dose, comprising a bag having an outer wall, wherein the outer wall has an outer surface and an inner surface which determines the inner volume of the package, and a composition contained in the inner volume of the package, which contains an aggressive chemical substance which contains an oxidising agent, a base or a combination thereof. Outer wall comprises a nonwoven fabric containing a plurality of fibres containing: (a) a sulphonate-modified polyvinyl alcohol (PVOH) fibre-forming material containing a sulphonate anionic monomer unit; (b) or a mixture of fibre-forming materials comprising a sulphonate-modified fibre-forming material of polyvinyl alcohol (PVOH) in combination with polyvinylpyrrolidone and a carboxyl-modified polyvinyl alcohol (PVOH) containing a carboxylate anionic monomer link. At that, fibre-forming material from PVOH modified with sulphonate groups has degree of hydrolysis of at least 95 %, and the sulphonate anionic monomer is present in an amount ranging from about 1 mol. % to about 5 mol. %.

EFFECT: proposed approach enables to obtain a water-soluble package that quickly releases the contents of the bag to ensure a more uniform distribution, which can remain water-soluble after storage in contact with the contents of the package, while with less tendency to stick to the other water-soluble package.

45 cl, 1 tbl, 1 ex

Description

This application claims the benefit of 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 62/908,582, filed September 30, 2019, which is incorporated herein by reference in its entirety.

Field of technology to which the invention relates

The present invention generally relates to a water-soluble nonwoven fabric and related compositions. More specifically, the invention relates to a water-soluble nonwoven fabric for packaging aggressive chemical compositions.

State of the art

Water-soluble packaging materials are commonly used to facilitate dispersion, pouring, dissolving and dispensing of the material to be delivered. Traditional packaging materials include water-soluble films, and bags made from them are commonly used to package formulations such as laundry, dishwashing detergents or harsh chemicals. The consumer can directly add the packaged composition to water. This advantageously ensures accurate dosing while eliminating the need for the consumer to measure the composition. Traditional water-soluble films may interact with the components of the package (e.g., harsh chemicals) or with ambient moisture, which may affect the properties of the film, for example, the solubility of the film may decrease over time when stored in contact with such chemicals, resulting in an undesirable residue remaining after dispensing, and/or the mechanical properties of the film may deteriorate over time. Another problem is that water-soluble films may discolor when stored in contact with harsh chemicals. In another type of problem, water-soluble films made from water-soluble polymers may adhere to processing equipment and/or other water-soluble films. Such problems may especially arise when the films are formed into bags and the bags are stored together in secondary packaging. In addition, some bags currently sold made from water-soluble polymer films have an unpleasant rubbery or plastic-like feel when touched by the consumer. Another type of problem occurs when water-soluble bags are intended, for example, for use in large quantities of water, the water-soluble bags may release their contents in a manner that results in a localized concentration of the contents rather than a more uniform distribution of the contents throughout the volume of the solution.

There is thus a need in the art for a water-soluble packaging that is pleasant to handle, that quickly releases the contents of the package to provide a more uniform distribution, that can remain water-soluble after storage in contact with the contents of the package, while having a reduced tendency to stick to other water-soluble packaging.

The essence of the invention

In one aspect of the present invention, there are provided single dose articles comprising a bag comprising an outer wall, wherein the outer wall has an outer surface, and the inner surface defines an inner volume of the bag, wherein the outer wall comprises a nonwoven web comprising a plurality of fibers comprising a sulfonate-modified PVOH fiber-forming material comprising a sulfonated anionic monomer unit, wherein the sulfonate-modified PVOH fiber-forming material has a degree of hydrolysis of at least 95%, and the sulfonated anionic monomer is present in an amount in the range of from about 1 mol.% to about 5 mol.%; and a composition contained in the inner volume of the bag.

In another aspect of the present invention, single dose articles are provided, comprising a pouch comprising an outer wall, wherein the outer wall has an outer surface, and the inner surface defines an inner volume of the pouch, wherein the outer wall comprises a nonwoven web comprising a plurality of fibers comprising a mixture of fiber-forming materials comprising (i) polyvinylpyrrolidone and (ii) polyvinyl alcohol (PVOH) modified with a sulfonate, PVOH modified with a carboxyl group, or both; and a composition contained in the inner volume of the pouch.

Another aspect of the present invention relates to single dose articles according to the present invention, in which the composition for treating a layer of liquid (pool) and/or water is contained in the internal volume of the bag, the composition for treating a layer of liquid and/or water contains an oxidizer, and the concentration of the oxidizer in the composition for treating a layer of liquid and/or water is in the range from 50% to 100% by weight; and wherein the oxidizer contains calcium hypochlorite, and the bag optionally contains a first coating containing an acid absorber, applied to at least a portion of the internal surface of the outer wall.

In another aspect of the present invention, single dose articles are provided according to the present invention, wherein the composition for treating a liquid and/or water layer is contained in the internal volume of the bag, the composition for treating a liquid and/or water layer contains an oxidizer, and the concentration of the oxidizer in the composition for treating a liquid and/or water layer is in the range from 50% to 100% by weight; and wherein the oxidizer contains trichloroisocyanuric acid, and the bag optionally contains a first coating containing an acid absorber applied to at least a portion of the internal surface of the outer wall.

In another aspect of the present invention, methods are provided for dispensing a composition into a large quantity of water, comprising the steps of contacting with the large quantity of water a single dose article according to the invention.

For the compositions described herein, optional features, including, but not limited to, components and composition ranges thereof, fiber-forming materials, multilayer structures, fiber geometry, and/or mechanical properties, are contemplated to be selected from the various aspects and embodiments provided herein.

Additional aspects and advantages will be apparent to those skilled in the art from a review of the following detailed description. Although the fibers, nonwoven webs, unit dose articles, and compositions of the present invention are capable of embodiment in various forms, the following description includes specific embodiments with the understanding that the disclosure is illustrative and is not intended to limit the disclosure to the specific embodiments described herein.

Disclosure of invention

The disclosure provided herein provides, in one aspect, single dose articles comprising a package comprising an outer wall, wherein the outer wall has an outer surface and the inner surface defines an interior volume of the package, the outer wall comprises a nonwoven web, and a composition contained in the interior volume of the package. In embodiments, the nonwoven web comprises a plurality of fibers comprising a fiber-forming material of sulfonate-modified polyvinyl alcohol ("PVOH") comprising a sulfonated anionic monomer unit. In embodiments, the fiber-forming material of sulfonate-modified PVOH has a degree of hydrolysis of at least 95%. In embodiments, the sulfonated anionic monomer is present in an amount of from about 1 mol% to about 5 mol%.

In another aspect of the present invention, single dose articles are provided, comprising a package comprising an outer wall, wherein the outer wall has an outer surface, and the inner surface defines an inner volume of the package, the outer wall comprises a nonwoven web, and a composition contained in the inner volume of the package. In embodiments, the nonwoven web comprises a plurality of fibers that are a mixture of fiber-forming materials. In embodiments, the mixture of fiber-forming materials comprises (i) polyvinylpyrrolidone and (ii) PVOH modified with a sulfonate, PVOH modified with a carboxyl group, or both.

In the disclosure provided herein, one aspect provides a water-soluble nonwoven web comprising a plurality of fibers. In embodiments, the plurality of fibers may comprise a mixture of fiber-forming materials comprising carboxyl-modified polyvinyl alcohol and sulfonate-modified polyvinyl alcohol, polyvinylpyrrolidone, or both, wherein the weight ratio of the carboxyl-modified polyvinyl alcohol fiber-forming material to the sulfonate and/or polyvinylpyrrolidone fiber-forming material is from about 3:1 to about 19:1. In embodiments, the plurality of fibers may comprise a blend of fibers comprising a fiber having a fiberizing material of carboxyl group-modified polyvinyl alcohol and a fiber comprising a fiberizing material of sulfonate-modified polyvinyl alcohol, a fiber comprising a fiberizing material of polyvinylpyrrolidone, or both types of fibers, wherein the weight ratio of the fiberizing material of carboxyl group-modified polyvinyl alcohol to the fiberizing materials of sulfonate and/or polyvinylpyrrolidone is from about 3:1 to about 19:1. In embodiments, the plurality of fibers may comprise a fiber blend comprising a first fiber comprising a fiberizing material of carboxyl group-modified polyvinyl alcohol, a fiberizing material of sulfonate-modified polyvinyl alcohol, or a fiberizing material of polyvinylpyrrolidone, and a second fiber comprising a blend of fiberizing materials comprising a carboxyl group-modified polyvinyl alcohol fiberizing material, a sulfonate-modified polyvinyl alcohol fiberizing material, a polyvinylpyrrolidone fiberizing material, or a combination thereof, wherein the weight ratio of the carboxyl group-modified polyvinyl alcohol fiberizing material to the sulfonate and/or polyvinylpyrrolidone fiberizing materials is from about 3:1 to about 19:1.

Aggressive chemicals include strongly acidic or alkaline chemical compounds that have a positive standard electrode potential and/or compounds that are highly hygroscopic so that they dry out moisture-containing materials.

In another aspect of the present invention, there is provided a water-soluble single-dose article comprising an outer wall, wherein the outer wall has an outer surface, and the inner surface defines an inner volume of the package, wherein the outer wall comprises a water-soluble nonwoven web as described herein, and a composition contained in the inner volume of the package. In embodiments, the composition may comprise an aggressive chemical substance.

The water-soluble single dose article of the present invention may be designed to provide one or more advantages, such as maintaining desirable properties of the nonwoven web in the presence of harsh chemicals, such as elasticity and solubility, resistance to degradation in the presence of harsh chemicals, resistance to coloring, improved hand feel compared to bags made from water-soluble film, less tendency to stick to other bags and/or secondary packaging compared to bags made from water-soluble film, and/or providing a more uniform release and distribution of contents in a large amount of water compared to bags made from water-soluble film.

All percentages, parts and ratios mentioned herein are based on the total dry weight of the fiber composition, nonwoven web composition or total weight of the composition of the contents of the bag of the present invention, as the case may be, and all measurements taken are at a temperature of about 25 ⁰ C, unless otherwise indicated. All such weights related to the listed ingredients are based on the active level and therefore do not include carriers or by-products that may be included in commercially available materials, unless otherwise indicated.

All ranges specified herein include all possible subsets of the ranges and any combinations of such subsets of the ranges. By default, ranges include the stated endpoints unless otherwise specified. When a range of values is specified, it is intended that each subset of the value between the upper and lower limits of that range and any other specified or subset of the value within the specified range is encompassed by the disclosure. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges and are also encompassed by the disclosure subject to any specifically excluded limit within the specified range. Where a specified range includes one or both limits, ranges excluding one or both of those included limits are also considered part of the disclosure.

It is expressly intended that for any numerical value disclosed herein, such as as a parameter of the described item or part of a range associated with the described item, an alternative that forms part of the description is a functionally equivalent range surrounding the specific numerical value (e.g., for a size disclosed as "40 mm", the alternative embodiment under consideration is "about 40 mm").

As used herein, and unless otherwise indicated, the term "nonwoven web" refers to a web or sheet comprising, consisting of, or essentially consisting of fibers arranged (e.g., by a carding process) and bonded to one another. Additionally, as used herein, the term "nonwoven web" includes any structure comprising a nonwoven web or sheet, including, for example, a nonwoven web or sheet having a film applied to the surface. Methods for making nonwoven webs from fibers are well known in the art, for example, as described in Nonwoven Fabrics Handbook, prepared by Ian Butler, edited by Subhash Batra et al., Printing by Design, 1999, incorporated herein by reference in its entirety. As used herein, and unless otherwise indicated, the term "film" refers to a continuous film or sheet, such as one produced by a casting or extrusion process.

As used herein and unless otherwise specified, the term "water-soluble" refers to any fiber, nonwoven web, or film having a dissolution time of 300 seconds or less at a specified temperature, as determined in accordance with MSTM-205, as set forth herein. For example, the dissolution time may optionally be 200 seconds or less, 100 seconds or less, 60 seconds or less, or 30 seconds or less at a temperature of about 80°C, about 70°C, about 60°C, about 50°C, about 40°C, about 20°C, or about 10°C. In embodiments in which the dissolution temperature is not specified, the water-soluble fiber, nonwoven web, or nonwoven composite article has a dissolution time of 300 seconds or less at a temperature no greater than about 80°C. As used herein and unless otherwise specified, the term "cold water soluble" refers to any fiber, nonwoven web, or nonwoven composite article having a dissolution time of 300 seconds or less at 10°C, as determined in accordance with MSTM-205. For example, the dissolution time may optionally be 200 seconds or less, 100 seconds or less, 60 seconds or less, or 30 seconds at 10°C. In embodiments, "water soluble film" means that at a thickness of 1.5 mils, the film dissolves in 300 seconds or less at a temperature no greater than 80°C. For example, a 1.5 mil (about 38 microns) thick water-soluble film may have a dissolution time of 300 seconds or less, 200 seconds or less, 100 seconds or less, 60 seconds or less, or 30 seconds or less at a temperature of about 70°C, about 60°C, about 50°C, about 40°C, about 30°C, about 20°C, or about 10°C in accordance with MSTM-205.

As used herein, the terms package(s) and bag(s) should be considered interchangeable. In some embodiments, the terms package and bag are respectively used to refer to a container made using a nonwoven web and a fully sealed container, preferably having a material sealed therein, for example in the form of a metered dose delivery system. Sealed bags may be made by any suitable method, including processes and elements such as heat sealing, solvent sealing, and adhesive sealing (for example, using a water-soluble adhesive).

As used herein and unless otherwise specified, the terms "wt%" and "wt%" are intended to mean the composition of the identified element in "dry" (water-free) parts by weight of the entire nonwoven web, including residual moisture in the nonwoven web, or parts by weight of the entire composition or coating, as the context requires.

As used herein and unless otherwise specified, the term "PHR" ("phr") is intended to mean the composition of the identified element in parts per hundred of water-soluble polymeric resin (whether PVOH or other polymeric resin unless otherwise specified) in a water-soluble nonwoven web or in a solution used to make the nonwoven web.

As used herein, the term "comprising" means that various components, ingredients, or steps may be used together in practicing the present disclosure. Accordingly, the term "comprising" includes the more restrictive terms "consisting essentially of" and "consisting of." The compositions of the present invention may comprise, consist essentially of, or consist of any of the required and optional elements disclosed herein. For example, a thermoformed pouch may "consist essentially of" a nonwoven web described herein to utilize its thermoforming characteristics, while including a non-thermoformed nonwoven web (e.g., a lid portion) and optional markings on the nonwoven web, such as by inkjet printing. The disclosure illustratively disclosed herein may be practiced in the absence of any element or step not specifically disclosed herein.

It is intended that the nonwoven webs, bags, and related methods of making and using them include embodiments that include any combination of one or more of the additional optional elements, features, and steps described below, unless otherwise noted.

The nonwoven web can be made by any suitable method, including carding, as is well known in the art, as described in the Nonwoven Fabrics Handbook, prepared by Ian Butler, edited by Subhash Batra et al., Printing by Design, 1999, incorporated herein by reference in its entirety. Methods of forming containers, such as bags, from nonwoven materials are known in the art. The nonwoven web can be used to form the container (bag) by any suitable method, including vertical form, fill and seal (VFFS) or thermoforming. The nonwoven web can be sealed by any suitable method, including, for example, solvent sealing or heat sealing of layers of the nonwoven web, such as around the periphery of the container. Advantageously, the nonwoven webs of the present invention can exhibit preferential shrinkage in the presence of heat and/or water (e.g., humidity). Accordingly, nonwoven webs may shrink under the influence of heat and/or water when formed into bags. The bags can be used, for example, for dosing materials intended to be dispensed in large quantities of water.

Nonwoven webs, bags, and related uses are intended to include embodiments that include any combination of one or more of the additional optional elements, features, and steps described below, unless otherwise noted.

Water-soluble fiber-forming materials

Typically, a water-soluble nonwoven web may include a plurality of fibers, including one fiber-forming material or a mixture of fiber-forming materials. In embodiments, the fiber-forming materials are water-soluble. In embodiments, the fibers are water-soluble.

Typically, the fibers of the present invention include at least one fiber-forming material made of polyvinyl alcohol. Polyvinyl alcohol is a synthetic polymer typically produced by the alcoholysis, commonly referred to as hydrolysis or saponification, of polyvinyl acetate. Fully hydrolyzed PVOH, in which substantially all of the acetate groups have been converted to alcohol groups, is a highly crystalline, strongly hydrogen-bonded polymer that is soluble only in hot water - at temperatures above about 140 °F (about 60 °C). If sufficient acetate groups remain after the polyvinyl acetate has been hydrolyzed, i.e., the PVOH polymer is partially hydrolyzed, the polymer is less hydrogen-bonded, less crystalline, and is generally soluble in cold water - less than about 50 °F (about 10 °C). Thus, the partially hydrolyzed polymer is a copolymer of vinyl alcohol and vinyl acetate, which is a copolymer of PVOH, but is commonly referred to as PVOH.

The polyvinyl alcohol may be a modified polyvinyl alcohol, such as a copolymer. The modified polyvinyl alcohol may include a copolymer or a higher polymer (e.g., a terpolymer) comprising one or more monomers in addition to the vinyl acetate/vinyl alcohol groups. Optionally, the modification is neutral, such as provided by ethylene, propylene, N-vinylpyrrolidone, or other types of uncharged monomers. Optionally, the modification is a cationic modification, such as provided by positively charged monomers. Optionally, the modification is an anionic modification. Thus, in some embodiments, the polyvinyl alcohol includes an anionically modified polyvinyl alcohol. The anionically modified polyvinyl alcohol may comprise a partially or fully hydrolyzed PVOH copolymer that comprises an anionic monomer unit, a vinyl alcohol monomer unit, and optionally a vinyl acetate monomer unit (i.e., when not fully hydrolyzed). In some embodiments, the PVOH copolymer may comprise two or more types of anionic monomer units. General classes of anionic monomer units that can be used for the PVOH copolymer include vinyl polymerization units corresponding to vinyl sulfonic acid monomers and their esters, vinyl monomers of monocarboxylic acids, their esters and anhydrides, dicarboxylic monomers having a polymerizable double bond, their esters and anhydrides, and alkali metal salts of any of the above. Examples of suitable anionic monomer units include vinyl polymerization units corresponding to vinyl anionic monomers including vinyl acetic acid, maleic acid, monoalkyl maleate, dialkyl maleate, maleic anhydride, fumaric acid, monoalkyl fumarate, dialkyl fumarate, itaconic acid, monoalkyl itaconate, dialkyl itaconate, citraconic acid, monoalkyl citraconate, dialkyl citraconate, citraconic anhydride, mesaconic acid, monoalkyl mesaconate, dialkyl mesaconate, glutaconic acid, monoalkyl glutaconate, dialkyl glutaconate, glutaconic anhydride, alkyl acrylates, alkyl alkacrylates, vinyl sulfonic acid, allyl sulfonic acid, ethylene sulfonic acid, 2-acrylamido-1-methylpropanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 2-methylacrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl acrylate, alkali metal salts of the foregoing compounds (e.g., sodium, potassium, or other alkali metal salts), esters of the foregoing (e.g., methyl, ethyl, or other C1-C4 or C6 alkyl esters), and combinations of the foregoing (e.g., multiple types of anionic monomers or equivalent forms of the same anionic monomer). In some embodiments, the PVOH copolymer may include two or more types of monomer units selected from neutral, anionic, and cationic monomer units.

The level of incorporation (degree of modification) of one or more anionic monomer units in the PVOH copolymers is not particularly limited. In embodiments, the one or more anionic monomer units are present in the PVOH copolymer in an amount from about 1 mol% or 2 mol% to about 6 mol% or 10 mol% (e.g., at least 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, or 4.0 mol% and/or up to about 3.0, 4.0, 4.5, 5.0, 6.0, 8.0, or 10 mol% in various embodiments). In embodiments, one or more anionic monomer units are present in the PVOH copolymer in an amount in the range of from about 1 mol% to 10 mol%, or from about 1 mol% to 8 mol%, or from about 1 mol% to 5 mol%, from about 2 mol% to about 6 mol%, from about 3 mol% to about 5 mol%, or from about 1 mol% to about 3 mol%.

The degree of hydrolysis (DH) of the PVOH homopolymers and PVOH copolymers included in the water-soluble fibers and nonwoven webs of the present invention can be in the range of from about 75% to about 99.9% (e.g., from about 79% to about 92%, from about 80% to about 90%, from about 88% to 92%, from about 86.5% to about 89%, or from about 88%, 90%, or 92%, such as for cold water soluble compositions; from about 90% to about 99%, from about 92% to about 99%, from about 95% to about 99%, from about 98% to about 99%, from about 98% to about 99.9%, about 96%, about 98%, about 99%, or more than 99%). DH, while specifically a measure of the amount of acetates removed from the polyvinyl acetate polymer (e.g., via hydrolysis, saponification), is most often used to understand the amount of acetate remaining on the PVOH polymer or copolymer. The acetate groups form the amorphous or non-crystalline regions of the PVOH copolymer. Therefore, as a general rule, the higher the DH, the relatively higher the crystallinity of the PVOH copolymer or PVOH copolymer blends. When a PVOH resin is described as having (or not having) a particular DH, unless otherwise stated, it is implied that the stated DH is the average DH for the PVOH resin.

In general, as the degree of hydrolysis decreases, the fibrous or nonwoven web made from the polymer will have lower mechanical strength but higher solubility at temperatures below about 20°C. As the degree of hydrolysis increases, the fibrous or nonwoven web made from the polymer becomes mechanically stronger and its thermoformability decreases. The degree of hydrolysis of the PVOH can be selected such that the solubility of the polymer in water depends on the temperature and thus also affects the solubility of the fiber and/or nonwoven web made from the polymer and additional ingredients. In one embodiment, the nonwoven web is cold water soluble. For a copoly(vinyl acetate and vinyl alcohol) polymer that does not include any other monomers (e.g., a homopolymer not copolymerized with an anionic monomer), the cold water soluble fiber or nonwoven web that is soluble in water at a temperature of less than 10 ^o C may include PVOH with a degree of hydrolysis in the range of from about 75% to about 90%, or in the range of from about 80% to about 90%, or in the range of from about 85% to about 90%. In another embodiment, the fiber or nonwoven web is hot water soluble. For a copoly(vinyl acetate and vinyl alcohol) polymer that does not include any other monomers (e.g., a homopolymer not copolymerized with an anionic monomer), the hot water soluble fiber or nonwoven web that is soluble in water at a temperature of at least about 60 ^o C may include PVOH with a degree of hydrolysis of at least about 98%.

The degree of hydrolysis of a polymer mixture can also be characterized by the arithmetically weighted average degree of hydrolysis ( ). For example, ( ) for a PVOH polymer that includes two or more PVOH polymers, is calculated using the formula,

where Wi is the weight percent of the corresponding PVOH polymer and Hi is the corresponding degrees of hydrolysis. When a polymer is said to have a certain degree of hydrolysis, the polymer may be a single polyvinyl alcohol polymer having the indicated degree of hydrolysis or a mixture of polyvinyl alcohol polymers having the indicated average degree of hydrolysis.

The viscosity of a PVOH polymer (µ) is determined by measuring a freshly prepared solution using a Brookfield viscometer type LV with a UL adapter as described in British Standard EN ISO 15023-2:2006 Annex E Brookfield Test method. In international practice, the viscosity of 4% aqueous solutions of polyvinyl alcohol is reported at 20 °C. All viscosities reported here in centipoise (cP) should be understood as referring to the viscosity of a 4% aqueous solution of polyvinyl alcohol at 20 °C unless otherwise stated. Similarly, when a polymer is described as having (or not having) a particular viscosity, unless otherwise stated, it is understood that the viscosity stated is the average viscosity for a polymer which by its nature has the corresponding molecular weight distribution, i.e. the logarithm of the average viscosity, as described below. It is well known in the art that the viscosity of PVOH polymers correlates with the weight average molecular weight. PVOH polymer, and viscosity is often used as an indicator of viscosity .

In embodiments, the PVOH resin may have a viscosity of from about 1.0 to about 50.0 cP, from about 1.0 to about 40.0 cP, or from about 1.0 to about 30.0 cP, such as about 4 cP, 8 cP, 15 cP, 18 cP, 23 cP, or 26 cP. In embodiments, the PVOH copolymers can have a viscosity of from about 1.0 to about 30.0 cP, such as about 1 cP, 1.5 cP, 2 cP, 2.5 cP, 3 cP, 3.5 cP, 4 cP, 4.5 cP, 5 cP, 5.5 cP, 6 cP, 6.5 cP, 7 cP, 7.5 cP, 8 cP, 8.5 cP, 9 cP, 9.5 cP, 10 cP, 11 cP, 12 cP, 13 cP, 14 cP, 15 cP, 17.5 cP, 18 cP, 19 cP, 20 cP, 21 cP, 22 cP, 23 cP, 24 cP, 25 cP, 26 cP, 27 cP, 28 cP, 29 cP, 30 cP, 31 cP, 32 cP, 33 cP, 34 cP, or 35 cP. In embodiments, the PVOH copolymers can have a viscosity of from about 21 cP to 26 cP. In embodiments, the PVOH copolymers can have a viscosity of from about 5 cP to about 14 cP.

Polyvinyl alcohols can change solubility characteristics. It is known to those skilled in the art that the acetate group in a copoly(vinyl acetate and vinyl alcohol) polymer (PVOH homopolymer) is hydrolyzed by acid or alkaline hydrolysis. As the degree of hydrolysis increases, a polymer composition made from the PVOH homopolymer will have increased mechanical strength but decreased solubility at lower temperatures (e.g., requiring hot water temperatures for complete dissolution). Accordingly, exposing a PVOH homopolymer to an alkaline environment can change the polymer from a polymer that dissolves quickly and completely in a given aqueous environment (e.g., a cold water environment) to a polymer that dissolves slowly and/or incompletely in an aqueous environment, potentially leaving behind an undissolved polymer residue.

PVOH copolymers with pendant carboxyl groups, such as, for example, maleate-modified PVOH, can form lactone rings between adjacent pendant carboxyl and alcohol groups, which reduces the solubility of the PVOH copolymer in water. In the presence of a strong base, the lactone rings can open over a period of several weeks under relatively warm (ambient) and high humidity conditions (e.g., through lactone ring-opening reactions to form the corresponding pendant carboxyl and alcohol groups with increased solubility in water. Thus, in contrast to the effect observed with PVOH homopolymers, it is believed that such a PVOH copolymer can become more soluble due to chemical interactions between the polymer and the alkaline composition inside the package during storage.

Certain sulfonates and derivatives thereof having polymerizable vinyl linkages can be copolymerized with vinyl acetate to form cold water soluble PVOH polymers that are stable in the presence of strong bases. The base catalyzed alcoholysis products of these copolymers, which can be used in water soluble fibers, are vinyl alcohol-sulfonate salt copolymers that dissolve rapidly. The sulfonate group in the PVOH copolymer can be converted to a sulfonic acid group in the presence of hydrogen ions, but the sulfonic acid group still provides excellent cold water solubility for the polymer. In embodiments, the vinyl alcohol-sulfonate salt copolymers do not contain residual acetate groups (i.e., are completely hydrolyzed) and therefore are not further hydrolyzed by either acid or alkaline hydrolysis. Generally, as the amount of modification increases, the solubility in water increases, so that sufficient modification with sulfonate or sulfonic acid groups inhibits hydrogen bonding and crystallinity, ensuring solubility in cold water. In the presence of acidic or basic compounds, the copolymer is generally unchanged, with the exception of sulfonate or sulfonic acid groups, which retain excellent solubility in cold water even in the presence of acidic or basic substances. Examples of suitable sulfonic acid comonomers (and/or alkali metal salt derivatives thereof) include vinyl sulfonic acid, allyl sulfonic acid, ethylene sulfonic acid, 2-acrylamido-1-methylpropanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-methacrylamido-2-methylpropanesulfonic acid and 2-sulfoethyl acrylate, with the preferred comonomer being 2-acrylamido-2-methylpropanesulfonic acid sodium salt (AMPS).

Water-soluble polymers, whether polyvinyl alcohol polymers or other polymers, can be blended. When the polymer blend includes a blend of polyvinyl alcohol polymers, the PVOH polymer blend can include a first PVOH polymer (a "first PVOH polymer") that can include a PVOH homopolymer or a PVOH copolymer that includes one or more types of anionic monomer units (e.g., a ter- (or higher co-) polymer) and a second PVOH polymer (a "second PVOH polymer") that can include a PVOH homopolymer or a PVOH copolymer that includes one or more types of anionic monomer units (e.g., a ter- (or higher co-) polymer). In some aspects, the PVOH polymer blend includes only the first PVOH polymer and the second PVOH polymer (e.g., a binary blend of the two polymers). Alternatively or additionally, the PVOH polymer blend or fiber or nonwoven web made therefrom can be characterized as being free or substantially free of other polymers (e.g., other water-soluble polymers, particularly other PVOH-based polymers, or both). As used herein, the term "substantially free" means that the first and second PVOH polymers comprise at least 95 wt.%, at least 97 wt.%, or at least 99 wt.% of the total amount of water-soluble polymers of the water-soluble fiber or nonwoven web. In other aspects, the water-soluble fiber or nonwoven web can include one or more additional water-soluble polymers. For example, a blend of PVOH polymers may include a third PVOH polymer, a fourth PVOH polymer, a fifth PVOH polymer, etc. (e.g., one or more additional PVOH homopolymers or PVOH copolymers with or without anionic monomer units). For example, a water-soluble nonwoven web may include at least a third (or fourth, fifth, etc.) water-soluble polymer that is different from a PVOH polymer (e.g., other than PVOH homopolymers or PVOH copolymers, with or without anionic monomer units).

Water-soluble polymers other than a PVOH polymer may include, but are not limited to, polyacrylate, water-soluble acrylate copolymer, polyvinylpyrrolidone, polyethyleneimine, pullulan, water-soluble natural polymer including, but not limited to, guar gum, acacia, xanthan gum, carrageenan, and starch, derivatives of water-soluble polymers including, but not limited to, modified starches, ethoxylated starch and hydroxypropylated starch, copolymers of the foregoing, and combinations of any of the foregoing. Other water-soluble polymers may include polyalkylene oxides, polyacrylamides, polyacrylic acids and their salts, celluloses, cellulose ethers, cellulose esters, cellulose amides, polyvinyl acetates, polycarboxylic acids and their salts, polyamino acids, polyamides, gelatins, methylcelluloses, carboxymethylcelluloses and their salts, dextrins, ethylcelluloses, hydroxyethylcelluloses, hydroxypropyl methylcelluloses, maltodextrins, polymethacrylates and combinations of any of the foregoing. Such water-soluble polymers, whether PVOH or other polymers, are commercially available from various sources. In embodiments, the fiber-forming material may include polyvinyl alcohol modified with a carboxyl group. In embodiments, the carboxyl group-modified PVOH comprises a maleate monomer unit selected from the group consisting of monomethyl maleate, maleic acid, maleic anhydride, alkali salts thereof, and a combination thereof. Thus, in embodiments, the carboxyl group-modified PVOH comprises maleate-modified PVOH. The term "maleate-modified PVOH" as used herein, unless otherwise specified, refers to a polyvinyl alcohol comprising monomer units obtained by polymerization with monomers selected from the group consisting of maleic acid, monoalkyl maleate, dialkyl maleate, and/or maleic anhydride. In embodiments, the maleate monomer unit can be monomethyl maleate.

In some embodiments, the maleate-modified PVOH is substantially free of lactone rings such that the modified PVOH has about 2 pendant carboxylate groups per maleate monomer unit. In embodiments, the maleate-modified PVOH may comprise from about 1.5 pendant carboxylate groups to 2 pendant carboxylate groups per maleate monomer unit, or from about 1.2 pendant carboxylate groups to about 2 pendant carboxylate groups per maleate monomer unit, or from about 1 pendant carboxylate group to about 2 pendant carboxylate groups per maleate monomer unit, such as about 2 pendant carboxylate groups per maleate monomer unit, or about 1.9 pendant carboxylate groups per maleate monomer unit, or about 1.8 pendant carboxylate groups per maleate monomer unit, or about 1.7 pendant carboxylate groups per maleate monomer unit. maleate monomer unit, or about 1.6 pendant carboxylate groups per maleate monomer unit, or about 1.5 pendant carboxylate groups per maleate monomer unit, or about 1.2 pendant carboxylate groups per maleate monomer unit, or about 1 pendant carboxylate group per maleate monomer unit.

In some embodiments, the fiberizing material comprises sulfonate-modified polyvinyl alcohol. In embodiments, the sulfonate-modified PVOH is the only polyvinyl alcohol fiberizing material that comprises the fiber. In embodiments, the nonwoven web is composed of fibers in which the sulfonate-modified PVOH is the only fiberizing material present. In embodiments, the fiberizing material comprises sulfonate-modified PVOH and a cellulose-based fiberizing material or a starch-based fiberizing material. In embodiments, the fiberizing material comprises sulfonate-modified PVOH and polyvinylpyrrolidone, a carboxyl group-modified PVOH containing a carboxylated anionic monomer unit, or both. In embodiments, the sulfonate-modified PVOH comprises a sulfonated anionic monomer unit selected from the group consisting of vinyl sulfonic acid, allyl sulfonic acid, ethylene sulfonic acid, 2-acrylamido-1-methylpropanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 2-methylacrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl acrylate, alkali metal salts thereof, and combinations thereof. In embodiments, the sulfonated anionic monomer unit is selected from the group consisting of 2-acrylamido-1-methylpropanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 2-methylacrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl acrylate, alkali metal salts thereof, and combinations thereof. In embodiments, the sulfonated anionic monomer unit is selected from the group consisting of 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 2-methylacrylamido-2-methylpropanesulfonic acid, alkali salts thereof, and combinations thereof. In embodiments, the sulfonated anionic monomer unit comprises AMPS. In embodiments, the sulfonate-modified PVOH fiber-forming material has a degree of hydrolysis of at least 95%. In embodiments, the sulfonate-modified PVOH fiber-forming material has a degree of hydrolysis in the range of 95% to 99.9%. In embodiments, the sulfonated anionic monomer unit is present in an amount in the range of about 1 mol% to about 5 mol%. In embodiments, the sulfonated anionic monomer unit is present in an amount in the range of about 1 mol% to about 3 mol%.

In general, the AMPS-modified PVOH copolymer or the maleate-modified PVOH copolymer can be selected to provide one or more benefits. For example, AMPS- or maleate-modified PVOH can provide increased resistance to harsh chemicals such as acids, oxidizing agents, and bases that can damage PVOH nonwovens. Without intending to be bound by theory, it is believed that AMPS modifications can inhibit acid-induced crosslinking of PVOH, which can cause a decrease in the solubility of the nonwoven in water, and AMPS modification and/or maleate modification can inhibit acid/base-induced polyene formation (condensation reactions), which can cause undesirable yellowing of the nonwoven. In addition, AMPS and maleate modifications can provide one or more benefits to the resulting nonwoven, such as a reduction in crystalline regions in the nonwoven, resulting in a reduction in dissolution time.

When the fiber-forming material comprises a PVOH copolymer comprising an anionic monomer unit, the level of incorporation of one or more anionic monomer units in the PVOH copolymer is not particularly limited. In embodiments, the one or more anionic monomer units are present in the PVOH copolymer in an amount in the range of from about 1 mol% to about 10 mol%, from about 1.5 mol% to about 8 mol%, about 2 mol%. % to about 6 mol %, from about 3 mol % to about 5 mol %, or from about 1 mol % to about 4 mol % (e.g., at least about 1.0, 1.5, 1.8, 2.0, 2.5, 3.0, 3.5, or 4.0 mol % and up to about 3.0, 4.0, 4.5, 5.0, 6.0, 8.0, or 10 mol % in various embodiments). In embodiments, the anionic monomer comprises a maleate monomer unit, and the maleate monomer unit is present in an amount in the range of about 1 mol % to 10 mol %, or about 1 mol % to 8 mol %, or about 1 mol % to 5 mol %. In embodiments, the anionic monomer comprises a maleate monomer unit, and the maleate monomer unit is present in an amount in the range of about 1 mol% to 5 mol%. In embodiments, the anionic monomer comprises a sulfonated anionic monomer unit, and the sulfonated anionic monomer unit is present in an amount in the range of about 1 mol% to 10 mol%, or about 1 mol% to 8 mol%, or about 1 mol% to 5 mol%. In embodiments, the anionic monomer comprises a sulfonated anionic monomer unit, and the amount of the sulfonated anionic monomer unit is in the range of about 1 mol% to 5 mol%.

Polyvinylpyrrolidone is a synthetic resin obtained by polymerization of the monomer N-vinylpyrrolidone. Many studies have been conducted to determine the molecular weight of PVP polymer. Low molecular weight polymers have narrower molecular weight distribution curves than high molecular weight compounds. Some methods for measuring the molecular weight of various PVP polymer products rely on sedimentation measurements, light scattering, osmometry, NMR spectroscopy, ebullimometry, and size exclusion chromatography to determine the absolute molecular weight distribution. These methods can measure any of the three molecular weight parameters, namely the number average (Mn), viscosity average (Mv), and weight average (Mw). Each of these characteristics can give different answers for the same polymer. Therefore, any literature review should know which molecular average is being discussed.

In embodiments, the polyvinylpyrrolidone may have a weight average molecular weight at least about 3000 g/mol. In various embodiments, the PPV may be in the range of about 3000 g/mol to about 10 million g/mol. In some embodiments, the PVR may have in the range of from about 30,000 g/mol to about 8 million g/mol, or from about 60,000 g/mol to 5 million g/mol, or from about 80,000 g/mol to about 5 million g/mol, or from about 100.00 g/mol to about 5 million g/mol, or from about 150,000 g/mol to about 4 million g/mol, or from about 200,000 g/mol to about 4 million g/mol, or about 500,000 g/mol to about 4 million g/mol, or from about 1 million g/mol to about 3 million g/mol. In embodiments, the PVP can have from about 1.2 million g/mol to about 3 million g/mol. In various embodiments, the PPV may have in the range of from about 3000 g/mol to about 5 million g/mol, such as about 3000 g/mol, 5000 g/mol, 10000 g/mol, 30000 g/mol, 50000 g/mol, 100,000 g/mol, 200,000 g/mol, 500,000 g/mol, 1 million g/mol, 2 million g/mol, 3 million g/mol, 4 million g/mol, or 5 million g/mol. The weight average molecular weight can be determined by those skilled in the art, for example, by methods such as size exclusion chromatography (gel permeation chromatography). When a HDPE resin is described as having (or not having) a particular molecular weight, unless otherwise stated, it is understood that the stated molecular weight is the average molecular weight of the resin, which by its nature has the corresponding molecular weight distribution.

Without intending to be bound by any theory, it is believed that high molecular weight PVP polymers as disclosed herein are preferred because they are resistant to migration from the nonwoven material when the nonwoven material is in contact with dry and/or hygroscopic components. It is believed that the higher the Mw, the more entangled the individual polymer chains can become, so that the PVP chains are less likely to separate from other components of the nonwoven material and migrate from the film.

The PVP polymer can provide a number of advantages when added as a fiber-forming material to the fiber of the nonwoven web described herein. For example, without intending to be bound by any theory, it is believed that the pyrrolidone functional groups of the PVP polymer can act as an acid trap and/or pH buffer by reacting with the H+ ions of the aggressive chemicals (shown below in Scheme 1), thereby inhibiting acid-induced crosslinking and discoloration of the polyvinyl alcohol. Additionally, PVOH homopolymer or copolymer nonwoven webs in contact with aggressive chemicals typically become brittle over time because the aggressive chemicals draw water and/or plasticizers from the nonwoven web. The aggressive chemicals can be hygroscopic, which can lead to the absorption of other polar solvents and materials, such as those commonly used as plasticizers. However, it is advantageous that the combination of PVOH and PVP copolymer in the fiber-forming materials described herein can help prevent brittleness of the nonwoven web in the presence of aggressive chemicals. PVP in the nonwoven materials described herein can act like a plasticizer, but is resistant to being drawn out of the nonwoven web by aggressive chemicals. PVP also allows the nonwoven webs to maintain flexibility even when the films contain relatively small amounts of traditional plasticizer and water.

As described herein, a combination of sulfonate-modified PVOH and carboxyl-modified PVOH can advantageously provide resistance to degradation in the presence of aggressive chemicals such as acids, oxidizing agents, or bases.

As described herein, the sulfonate-modified PVOH can advantageously provide resistance to degradation of the nonwoven fabric in the presence of aggressive chemicals, such as base-based oxidizing agents. The term "base-mediated oxidizing agent" as used herein refers to an oxidizing agent that oxidizes other chemical compounds using a basic mechanistic oxidation pathway. A basic mechanistic oxidation pathway refers to a pathway in which a base, such as -OH, initiates or catalyzes an oxidation reaction of a reactant. For example, sodium hypochlorite, calcium hypochlorite, and monovalent and divalent salts having a structure similar to sodium hypochlorite and calcium hypochlorite are considered base-mediated oxidizing agents.

As described herein, the combination of PVOH and PVP can advantageously provide resistance to degradation in the presence of aggressive chemicals such as acids, oxidizing agents, or bases. For example, when PVOH is used as the only resin, an aggressive chemical can react with PVOH, rapidly degrading the nonwoven web. In contrast, it has been found that the combination of PVOH and PVP can stop or at least slow down the degradation of the nonwoven web. Without wishing to be bound by any theory, it is believed that the pyrrolidone functional groups of PVP can act as acid traps by reacting with H+ ions from aggressive chemicals, preventing the acid-catalyzed removal of hydroxyl units by H+ ions from vinyl alcohol, thereby inhibiting the degradation of polyvinyl alcohol. Conventional water-soluble PVOH films tend to degrade in the presence of harsh chemicals such as chlorine-based disinfectants and other oxidizing chemicals, acids, and some bases. Excessive oxidation causes the films to become water-insoluble, making them ineffective as single-dose packaging agents. Without wishing to be bound by theory, it is believed that hypochlorite ions produced by some harsh chemicals oxidize the pendant -OH groups in the PVOH copolymer film, creating carbonyl groups on the polymer backbone. The carbonyl group is an intermediate step in polyene formation (and yellowing) because it creates an acidic alpha hydrogen. The carbonyl group is also an intermediate in chain scission. In addition, hydrochloric acid, formed when exposed to certain aggressive chemicals, can react with the hydroxyl group to form unsaturated bonds in the polymer backbone, which can lead to decreased water solubility and also to discoloration of the film. In any case, the removal of the side -OH groups makes the films increasingly insoluble in water.

Nonwoven webs comprising typical homopolymers or copolymers of PVOH as the sole fiber-forming material preferably do not become brittle when in contact with aggressive chemicals because residual water migrates from the nonwoven web in the presence of aggressive chemicals; however, such loss of water may result in shrinkage of the fibers and, ultimately, the nonwoven web. In addition, preferably, the sulfonate-modified PVOH and/or PVP may act similarly to a rheology modifier of the carboxyl-modified PVOH, allowing control of the flow of the fiber-forming material during fiber production, as well as imparting chemical compatibility to the carboxyl-modified PVOH in the presence of aggressive chemicals by inhibiting the degradation of the carboxyl-modified PVOH under the influence of aggressive chemicals.

The water-soluble nonwoven web described herein may include a carboxyl group-modified PVOH fiber-forming material and sulfonate-modified PVOH fiber-forming materials and/or polyvinylpyrrolidone may be supplied in a weight ratio of from about 3:1 to about 19:1, respectively. In embodiments, the weight ratio of the carboxyl group-modified PVOH fiber-forming material to the sulfonate-modified PVOH and/or polyvinylpyrrolidone fiber-forming materials is from about 3:1 to about 18.2, from about 3:1 to about 17:1, from about 5:1 to about 15:1, from about 5:1 to about 12:1, from about 5:1 to about 9:1, from about 6:1 to about 9:1, or from about 6.5:1 to about 7.5:1 by weight, respectively. In embodiments, the weight ratio of the carboxyl group-modified PVOH fiber-forming material to the sulfonate-modified PVOH and/or polyvinylpyrrolidone fiber-forming materials is from about 5:1 to about 15:1, from about 5:1 to about 12:1, about 5:1 to about 9:1, from about 6:1 to about 9:1, from about 6.5:1 to about 7.5:1, from about 3:1 to about 6.5:1, or from about 3:1 to about 5:1 by weight, respectively.

In embodiments, the water-soluble nonwoven web disclosed herein may include a plurality of fibers comprising a mixture of fiber-forming materials comprising (i) polyvinylpyrrolidone and (ii) sulfonate-modified PVOH, carboxyl-modified PVOH, or both. In embodiments, the weight ratio of polyvinylpyrrolidone fiber-forming materials to sulfonate-modified PVOH fiber-forming materials, carboxyl-modified PVOH fiber-forming materials, or both is from about 1:1 to about 1:19 by weight, respectively. In embodiments of the invention, the weight ratio of polyvinylpyrrolidone fiber-forming materials to sulfonate-modified PVOH fiber-forming materials, carboxyl-modified PVOH fiber-forming materials, or both is from about 1:3 to about 1:19, from about 1:5 to about 1:15 by weight, from about 1:5 to about 1:12 by weight, from about 1:5 to about 1:9 by weight, from about 1:6 to about 1:9 by weight, or from about 1:6.5 to about 1:7.5 by weight, respectively.

Water-soluble non-woven fabric.

The water-soluble nonwoven web of the present invention typically includes a plurality of water-soluble fibers. Nonwoven web typically refers to an arrangement of fibers bonded to each other, wherein the fibers are neither woven nor knitted. Typically, the plurality of water-soluble fibers can be arranged in any orientation. In embodiments, the plurality of water-soluble fibers are randomly arranged (i.e., have no orientation). In embodiments, the plurality of water-soluble fibers are arranged in a unidirectional orientation. In embodiments, the plurality of water-soluble fibers are arranged in a bidirectional orientation. In some embodiments, the plurality of water-soluble fibers are multidirectional, having different arrangements in different areas of the nonwoven web.

Typically, the plurality of fibers in any given nonwoven web may include any of the fiberizing materials disclosed herein. The nonwoven web may include (1) one fiber type, including one fiberizing material, (2) one fiber type, including a mixture of fiberizing materials, (3) a mixture of fiber types, wherein each fiber type includes one fiberizing material, (4) a mixture of fiber types, wherein each fiber type includes a mixture of fiberizing materials, or (5) a mixture of fiber types, wherein each fiber type includes one fiberizing material or a mixture of fiberizing materials. In embodiments including a mixture of fiber types, the different fiber types may differ in diameter, length, strength, shape, stiffness, elasticity, solubility, melting point, glass transition temperature (Tg), chemical composition of the fiberizing material, color, or a combination thereof.

In embodiments, a plurality of water-soluble fibers comprise a polyvinyl alcohol polymer. In an improvement of the previous embodiment, the water-soluble fiber comprises a PVOH copolymer. In embodiments, the water-soluble fiber comprises a single PVOH copolymer resin. In embodiments, the water-soluble fiber comprises a mixture of fiber-forming materials, including a mixture of polyvinyl alcohol polymers. In embodiments, the water-soluble fiber comprises a mixture of fiber-forming materials, including a mixture of polyvinyl alcohol polymer and PVP polymer. In embodiments, the water-soluble polymer comprises two or more PVOH copolymers and a PVP polymer.

In embodiments, the nonwoven web may include a plurality of fibers, including a fiber-forming material of sulfonate-modified PVOH comprising a sulfonated anionic monomer unit. In embodiments, the fiber-forming material of sulfonate-modified PVOH has a degree of hydrolysis of at least 95%. In embodiments, the sulfonated anionic monomer is present in an amount of from about 1 mol% to about 5 mol%.

In embodiments, a nonwoven web or unit dose as described herein that includes fibers comprising a sulfonate-modified PVOH, such as an AMPS-modified PVOH, that has a degree of hydrolysis of at least 95%, and a sulfonated anionic monomer is present in an amount in the range of from about 1 mol% to about 5 mol% can provide one or more advantages. For example, increased resistance to aggressive chemicals, such as base-mediated oxidants, which cause degradation of the nonwoven web. In addition, the sulfonate-modified PVOH fiber-forming material can provide a nonwoven web having good shelf-life properties (e.g., retained solubility properties and resistance to discoloration), as determined by exposing the web to a base-mediated oxidizing composition, such as calcium hypochlorite, for 6 weeks at 38°C and 80% relative humidity in an environment. Such webs can exhibit a disintegration time of 300 seconds or less according to MSTM 205 in water at 23°C and/or maintain a b* value of 3.5 or less or 3.0 or less. The 38°C and 80% relative humidity environment can be maintained by packaging the water-soluble nonwoven webs in contact with the base-mediated oxidizing agent in secondary packaging made of 4 mil high-density polyethylene (HDPE) film.

In embodiments, the nonwoven web may include a plurality of fibers comprising a mixture of fiber-forming materials comprising (i) polyvinylpyrrolidone and (ii) sulfonate-modified PVOH, carboxyl group-modified PVOH, or both. In embodiments, the mixture of fiber-forming materials may include polyvinylpyrrolidone and sulfonate-modified PVOH. In embodiments, the mixture of fiber-forming materials may include polyvinylpyrrolidone and carboxyl group-modified PVOH. In embodiments, the mixture of fiber-forming materials may include polyvinylpyrrolidone, sulfonate-modified PVOH, and carboxyl group-modified PVOH.

In embodiments, a nonwoven web or a single dose as described herein that includes fibers that include a combination of polyvinylpyrrolidone and a fiber-forming material of PVOH modified with a carboxyl group, PVOH modified with a sulfonate, or both, can provide one or more advantages. For example, increased resistance to aggressive chemicals such as acids, oxidizers and bases that cause damage to the nonwoven web. In addition, the combination can provide a nonwoven web that has good long-term storage properties (e.g., retention of solubility properties and resistance to discoloration), as determined by exposing the web to a trichloroisocyanuric acid (TCCA) or sodium bisulfate (SBS) composition for 8 weeks at 38 ° C and 80% relative humidity under ambient conditions. Such webs may exhibit a disintegration time of not more than 300 seconds in accordance with MSTM 205 in water at 23°C, leave not more than 50% nonwoven web residue based on the surface area of the original nonwoven web and the nonwoven web after testing in accordance with MSTM 205 in water at 23°C and/or maintain a b* value of not more than 3.5. TCCA is considered one of the most aggressive oxidizers in the art and, therefore, is considered a good indicator for all aggressive chemicals. Environmental conditions of 38°C and 80% relative humidity can be maintained by packaging water-soluble nonwoven webs in contact with aggressive chemicals in secondary packaging made of 4 mil high-density polyethylene (HDPE) film.

In embodiments, the water-soluble nonwoven fabric may include a plurality of fibers, including:

(a) a blend of fiber-forming materials comprising (i) a carboxyl group-modified PVOH and (ii) a and (ii) a sulfonate-modified PVOH, PVP, or both;

(b) a blend of fibres comprising (iii) a fibre comprising a carboxyl group-modified PVOH fibre-forming material and (iv) a fibre comprising a sulfonate-modified PVOH fibre-forming material, a fibre comprising a PVP fibre-forming material, or fibres of both types; or

(c) a blend of fibers comprising (v) a first fiber comprising a carboxyl group-modified PVOH fiberizing material, a sulfonate-modified PVOH fiberizing material, or a PVP fiberizing material, and (vi) a second fiber comprising a blend of fiberizing materials comprising a carboxyl group-modified PVOH fiberizing material, a sulfonate-modified PVOH fiberizing material, a PVP fiberizing material, or a combination thereof,

wherein in any of (a), (b) and (c), the weight ratio of the carboxyl group-modified PVOH fiber-forming material to the sulfonate-modified PVOH and/or PVP fiber-forming material is from about 3:1 to about 19:1 by weight, respectively.

In embodiments, the mixture of fiberizing materials (a) may comprise (i) a maleate-modified PVOH fiberizing material and (ii) a sulfonate-modified PVOH fiberizing material. In embodiments, the mixture of fiberizing materials (a) may comprise (i) a maleate-modified PVOH fiberizing material and (ii) a PVP fiberizing material. In embodiments, the mixture of fiberizing materials (a) may comprise (i) a maleate-modified PVOH fiberizing material and (ii) a sulfonate-modified PVOH fiberizing material and a PVP fiberizing material. In embodiments, the mixture of fiberizing materials (a) may comprise (ii) a PVP fiberizing material. In improvements to the previous embodiments, the sulfonate-modified PVOH fiberizing material comprises AMPS.

In embodiments, the fiber mixture (b) may comprise (iii) a fiber comprising a maleate-modified PVOH fiberizing material and (iv) a fiber comprising a sulfonate-modified PVOH fiberizing material. In embodiments, the fiber mixture (b) may comprise (iii) a fiber comprising a maleate-modified PVOH fiberizing material and (iv) a fiber comprising a PVP fiberizing material, in embodiments, the fiber mixture (b) may comprise (iii) a fiber comprising a maleate-modified PVOH fiberizing material and (iv) a fiber comprising a sulfonate-modified PVOH fiberizing material and a fiber comprising a PVP fiberizing material. In embodiments, the fiber mixture (b) may comprise (iv) a fiber comprising a PVP fiberizing material. In improvements to the previous embodiments, the sulfonate-modified PVOH fiber-forming material comprises AMPS.

In embodiments, the fiber mixture (c) may include (v) a first fiber comprising a fiber-forming material of carboxyl group-modified PVOH and (vi) a second fiber comprising a mixture of fiber-forming materials comprising a fiber-forming material of carboxyl group-modified PVOH and a fiber-forming material of sulfonate-modified PVOH. In embodiments, the fiber mixture (c) may include (v) a first fiber comprising a fiber-forming material of carboxyl group-modified PVOH and (vi) a second fiber comprising a mixture of fiber-forming materials comprising a fiber-forming material of carboxyl group-modified PVOH and a fiber-forming material of PVP. In embodiments, the fiber mixture (c) may comprise (v) a first fiber comprising a fiberizing material of carboxyl-modified PVOH, and (vi) a second fiber comprising a mixture of fiberizing materials comprising a fiberizing material of carboxyl-modified PVOH, a fiberizing material of sulfonate-modified PVOH, and a fiberizing material of PVP. In embodiments, the fiber mixture (c) may comprise (vi) a second fiber comprising a fiberizing material of PVP. In improvements to the previous embodiments, the carboxyl-modified PVOH comprises maleate-modified PVOH, and the fiberizing material of sulfonate-modified PVOH comprises AMPS.

In embodiments, the fiber mixture (c) may include (v) a first fiber comprising a sulfonate-modified PVOH fiberizing material, and (vi) a second fiber comprising a mixture of fiberizing materials comprising a carboxyl-modified PVOH fiberizing material and a sulfonate-modified PVOH fiberizing material. In embodiments, the fiber mixture (c) may include (v) a first fiber comprising a sulfonate-modified PVOH fiberizing material, and (vi) a second fiber comprising a mixture of fiberizing materials comprising a carboxyl-modified PVOH fiberizing material and a PVP fiberizing material or a combination thereof. In embodiments, the fiber mixture (c) may comprise (v) a first fiber comprising a sulfonate-modified PVOH fiberizing material and (vi) a second fiber comprising a mixture of fiberizing materials comprising a carboxyl-modified PVOH fiberizing material, a sulfonate-modified PVOH fiberizing material, and a PVP fiberizing material. In improvements of the previous embodiments, the carboxyl-modified PVOH comprises maleate-modified PVOH, and the sulfonate-modified PVOH fiberizing material comprises AMPS.

In embodiments, the fiber mixture (c) may include (v) a first fiber comprising a PVP fiberizing material, and (vi) a second fiber comprising a mixture of fiberizing materials comprising a carboxyl group-modified PVOH fiberizing material and a sulfonate-modified PVOH fiberizing material. In embodiments, the fiber mixture (c) may include (v) a first fiber comprising a PVP fiberizing material, and (vi) a second fiber comprising a mixture of fiberizing materials comprising a carboxyl group-modified PVOH fiberizing material and a PVP fiberizing material. In embodiments, the fiber mixture (c) may comprise (v) a first fiber comprising a PVP fiberizing material, and (vi) a second fiber comprising a mixture of fiberizing materials comprising a carboxyl-modified PVOH fiberizing material, a sulfonate-modified PVOH fiberizing material, and a PVP fiberizing material. In improvements to the previous embodiments, the carboxyl-modified PVOH comprises maleate-modified PVOH, and the sulfonate-modified PVOH fiberizing material comprises AMPS.

In embodiments, a water-soluble nonwoven web as described herein that includes a sulfonate-modified PVOH fiber-forming material, such as AMPS-modified PVOH, or a carboxyl-modified PVOH fiber-forming material, such as maleate-modified PVOH, or a PVP fiber-forming material can be selected to provide one or more advantages. In embodiments, a blend of fibers and/or fiber-forming materials that includes maleate-modified PVOH and AMPS-modified PVOH, PVP, or a combination thereof can provide increased resistance to aggressive chemicals such as acids, oxidizers, and bases that cause damage to the water-soluble nonwoven material.

In embodiments, a water-soluble nonwoven web or a single dose as described herein that includes fibers that include a combination of a fiber-forming material of carboxyl group-modified PVOH and fiber-forming materials of sulfonate-modified PVOH and/or PVP can provide one or more advantages. For example, increased resistance to aggressive chemicals such as acids, oxidizers, and bases that damage the water-soluble film. In addition, the combination can provide a water-soluble web that has good long-term storage properties as determined by exposing the web to a composition with trichloroisocyanuric acid (TCCA) or sodium bisulfate (SBS) for 8 weeks in an atmosphere at 38°C and 80% relative humidity under ambient conditions. Such webs may exhibit a disintegration time of 300 seconds or less in accordance with MSTM 205 in water at 23°C, leave behind 50% or less of the nonwoven web residue based on the surface area of the original nonwoven web and the nonwoven web after testing in accordance with MSTM 205 in water at 23°C, maintain an average elongation of at least 90%, and/or maintain a b* value of 3.5 or less. TCCA is considered to be one of the most aggressive oxidizers in the art and is therefore a good indicator for all aggressive chemicals. Environmental conditions of 38°C and 80% relative humidity were maintained by packaging the water-soluble nonwoven webs in contact with aggressive chemicals in secondary packaging made of 4 mil high-density polyethylene (HDPE) film.

The nonwoven webs may further comprise fibers comprising a fiber-forming material comprising one or more water-soluble polymers including, but not limited to, polyvinyl alcohols (e.g., carboxyl group-modified PVOH comprising a carboxylated anionic monomer unit), polyvinylpyrrolidone, water-soluble acrylate copolymers, polyethyleneimine, pullulan, water-soluble natural polymers including, but not limited to, guar gum, acacia, xanthan gum, carrageenan and starch, a water-soluble polymer modified with starches, copolymers of the foregoing, or a combination thereof. Other water-soluble polymers may include polyalkylene oxides, polyacrylamides, celluloses, cellulose ethers, cellulose esters, cellulose amides, polyvinyl acetates, polycarboxylic acids and their salts, polyamino acids, polyamides, gelatins, methylcelluloses, carboxymethylcelluloses and their salts, dextrins, ethylcelluloses, hydroxyethylcelluloses, hydroxypropyl methylcelluloses, maltodextrins, polymethacrylates, or combinations thereof. Such water-soluble polymers are commercially available from various sources. In one embodiment, the type and/or amount of the additional polymer(s) will not cause the water-soluble nonwoven web to have less resistance to an aggressive chemical. In embodiments, (a) the plurality of fibers further comprises a fiber comprising cellulose, starch, carboxyl group modified PVOH comprising a carboxylated anionic monomer unit, or a combination thereof; (b) the plurality of fibers comprising a sulfonate-modified PVOH fiber-forming material further comprises a fiber-forming material comprising cellulose, starch, polyvinylpyrrolidone, carboxyl group modified PVOH comprising a carboxylated anionic monomer unit, or a combination thereof; or (c) a combination of (a) and (b). In embodiments, the plurality of fibers may further comprise a fiber comprising cellulose, starch, carboxyl group modified PVOH comprising a carboxylated anionic monomer unit, or a combination thereof. In embodiments, the plurality of fibers may comprise a fiber comprising a mixture of fiber-forming materials comprising a sulfonate-modified PVOH fiber-forming material and cellulose, starch, polyvinylpyrrolidone, carboxyl-modified PVOH comprising a carboxylated anionic monomer unit, or a combination thereof. In embodiments, the cellulose may comprise cellulose, carboxymethyl cellulose (CMC), hydroxymethyl cellulose (HMC), hydropropyl methyl cellulose (HPMC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), methyl cellulose, ethyl cellulose, ethyl methyl cellulose, salts of the foregoing, or combinations of the foregoing. In embodiments, the cellulose may comprise sodium carboxymethyl cellulose (CMC). In embodiments, the CMC may have from about 20% to about 60% substitution.

The water-soluble fibers and/or water-soluble nonwoven webs may include other auxiliary agents and processing agents such as, but not limited to, plasticizers, plasticizer compatibilizers, surfactants, colorants, acid scavengers, lubricants, release agents, fillers, diluents, crosslinking agents, anti-adhesives, antioxidants, tackifiers, defoamers, nanoparticles such as silicate-type layered nanoclays (e.g., sodium montmorillonite), bleaching agents (e.g., sodium metabisulfite, sodium bisulfate, or others), repellent agents such as bittering agents (e.g., denatonium salts such as denatonium benzoate, denatonium saccharide, and denatonium chloride; sucrose octaacetate; quinine; flavonoids such as quercetin and naringen; and quassinoids such as quassin and brucine) and pungent substances (e.g. capsaicin, piperine, allyl isothiocyanate, and resinferatoxin), cellulose, starch and other functional ingredients in amounts appropriate to their intended purpose. Specific such auxiliary agents and processing agents may be selected from those suitable for use in water-soluble fibers or those suitable for use in water-soluble nonwoven fabrics.

In embodiments, the water-soluble fiber and/or nonwoven web comprises cellulose, starch, or a combination thereof. In embodiments, the water-soluble fiber and/or nonwoven web comprises cellulose. In embodiments, the water-soluble fiber and/or nonwoven web comprises starch.

In embodiments, the water-soluble fibers and water-soluble nonwoven webs are free of adjuvants. As used herein and unless otherwise indicated, "free of adjuvants" with respect to a fiber means that the fiber includes less than about 0.01 wt. %, less than about 0.005 wt. %, or less than about 0.001 wt. % adjuvants, based on the total weight of the fiber. As used herein and unless otherwise indicated, the term "free of adjuvants" with respect to a nonwoven web means that the nonwoven web includes less than about 0.01 wt. %, less than about 0.005 wt. %, or less than about 0.001 wt. % adjuvants, based on the total weight of the nonwoven web. In embodiments, the water-soluble fibers include a plasticizer. In embodiments, the water-soluble fibers include a surfactant. In embodiments, the nonwoven web includes a plasticizer. In embodiments, the nonwoven web includes a surfactant. In embodiments, the water-soluble fibers do not contain auxiliary substances other than plasticizers, surfactants, cellulose, starch, or combinations thereof. In embodiments, the water-soluble nonwoven webs do not contain auxiliary substances other than plasticizers, surfactants, cellulose, starch, or combinations thereof.

A plasticizer is a liquid, solid, or semi-solid that is added to a material (usually a resin or elastomer) to make the material softer, more flexible (by lowering the glass transition temperature of the polymer), and easier to process. Alternatively, the polymer may be internally plasticized by chemically modifying the polymer or monomer. Additionally or alternatively, the polymer may be externally plasticized by adding a suitable plasticizing agent. Water has been found to be a very effective plasticizer for PVOH and other polymers; including but not limited to water-soluble polymers, however, the volatility of water makes its use limited because polymer nonwoven webs must have at least some resistance (strength) to a variety of environmental conditions, including low and high relative humidity.

The plasticizer may include, but is not limited to, glycerin, diglycerin, sorbitol, ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tetraethylene glycol, propylene glycol, polyethylene glycols with a molecular weight of up to 400, neopentyl glycol, trimethylolpropane, polyether polyols, 2-methyl-1,3-propanediol (MPDiol®), ethanolamines, maltitol, and mixtures thereof. In embodiments, the plasticizer is selected from the group consisting of glycerin, maltitol, trimethylolpropane, or a combination thereof. The total amount of non-aqueous plasticizer contained in the fiber can be about 1 wt. % to about 45 wt. %, or from about 5 wt. % to about 45 wt. %, or about 10 wt. % to about 40 wt. %, or about 20 wt. % to about 30 wt. %, about 1 wt. % to about 4 wt. %, or about 1.5 wt. % to about 3.5 wt. %, or about 2.0 wt. % to about 3.0 wt. %, such as about 1 wt. %, about 2.5 wt. %, about 5 wt. %, about 10 wt. %, about 15 wt. %, about 20 wt. %, about 25 wt. %, about 30 wt. %, about 35 wt. %, or about 40 wt. %, based on the total weight of the fiber.

Surface-active agents for use in fibers are well known in the art. Optionally, surface-active agents are included to aid in dispersion of the fibers during carding. Suitable surfactants for the fibers of the present invention include, but are not limited to, dialkyl sulfosuccinates, lactylated fatty acid esters of glycerol and propylene glycol, lactyl esters of fatty acids, sodium alkyl sulfates, polysorbate 20, polysorbate 60, polysorbate 65, polysorbate 80, alkyl polyethylene glycol ethers, lecithin, acetylated fatty acid esters of glycerol and propylene glycol, sodium lauryl sulfate, acetylated fatty acid esters, myristyl dimethylamine oxide, trimethyltalyl alkyl ammonium chloride, quaternary ammonium compounds, quaternary amines, alkali metal salts of higher fatty acids containing from about 8 to about 24 carbon atoms, alkyl ethers of polyethylene glycol, alkyl sulfates, alkyl polyethoxylate sulfates, alkyl benzene sulfonates, monoethanolamine, ethoxylate lauryl alcohol, propylene glycol, diethylene glycol, cocamides, salts thereof, and combinations of any of the foregoing. In embodiments, the surfactant comprises quaternary amines, myristyl dimethylamine oxide, polyethylene glycol alkyl ether, cocamides, or a combination thereof.

Suitable surfactants may include nonionic, cationic, anionic, and zwitterionic classes. Suitable surfactants include, but are not limited to, propylene glycols, diethylene glycols, monoethanolamine, polyoxyethylene polyoxypropylene glycols, alcohol ethoxylates, alkylphenol ethoxylates, tertiary acetylene glycols and alkanolamides (nonionic), polyoxyethylene amines, quaternary ammonium salts and quaternized polyoxyethylene amines (cationic), alkali metal salts of higher fatty acids containing from about 8 to about 24 carbon atoms, alkyl sulfates, alkyl polyethoxylate sulfates, and alkyl benzene sulfonates (anionic), and amine oxides, N-alkyl betaines, and sulfobetaines (zwitterions). Other suitable surfactants include sodium dioctyl sulfosuccinate, lactylated fatty acid esters of glycerol and propylene glycol, lactylated fatty acid esters, sodium alkyl sulfates, polysorbate 20, polysorbate 60, polysorbate 65, polysorbate 80, lecithin, acetylated fatty acid esters of glycerol and propylene glycol and acetylated fatty acid esters and combinations thereof. In various embodiments, the amount of surfactant in the fiber is in the range of from about 0.01 wt.% to about 2.5 wt.%, from about 0.1 wt.% to about 2.5 wt.%, from about 1.0 wt.% to about 2.0 wt.%, from about 0.01 wt.% to 0.25 wt.%, or from about 0.10 wt.% to 0.20 wt.%.

In particular embodiments, the surfactant used in the water-soluble films may be a quaternary ammonium surfactant or other surfactant that is basic and includes a hindered amine and can effectively provide antioxidant protection against an aggressive chemical. For example, myristyl (C ₁₄ ) dimethylamine oxide, dioctyl dimethyl ammonium chloride salts, or a combination thereof can provide the film with advantageous antioxidant protection.

In embodiments, the water-soluble nonwoven webs herein may further comprise one or more acid scavengers and/or antioxidants. It is believed that the acid scavengers and/or antioxidants reduce the damaging effects of the composition on the water-soluble nonwoven web, such as reducing the degradation of the water-soluble nonwoven web, or reducing the yellowing of the water-soluble nonwoven web, or maintaining the tensile strength of the water-soluble nonwoven web. In addition, without intending to be bound by theory, it is believed that the inclusion of an acid scavenger or antioxidant will mitigate acid-catalyzed hydrolysis and condensation reactions and help reduce the amount of acid in the nonwoven web environment, which can promote the oxidative activity of hypochlorite in the form of hypochlorous acid.

In some embodiments, the acid scavenger may comprise one or more of N-vinylpyrrolidone, sodium metabisulfite, activated olefins, maleate molecules (e.g., maleic acid and its derivatives), allyl compounds (e.g., allyl alcohols, allyl acetates, etc.), ethylene-containing compounds, quaternary ammonium compounds, amines (e.g., pyridine, monoethanolamine, methylamine, aniline), and tertiary amine-containing compounds. The acid scavenger may be included in the films described herein in an amount in the range of from about 0.25 PHR to about 15 PHR, such as about 0.25 PHR, about 1 PHR, about 1.5 PHR, about 2 PHR, about 3 PHR, about 4 PHR, about 5 PHR, about 5.5 PHR, about 6 PHR, about 6.5 PHR, about 7 PHR, about 8 PHR, about 9 PHR, about 10 PHR, or about 15 PHR (Parts per Hundred of Resin).

In embodiments, the acid absorber can be located in or on the fiber, in or on the nonwoven web, or in both. In embodiments, the acid absorber can be applied to the fiber, to the nonwoven web, or to both. In embodiments, the acid absorber can be distributed throughout the nonwoven web. The acid absorber can be adsorbed by the fibers throughout the nonwoven web or bound by static forces. For example, the acid absorber can be added as the fibers are laid down so that the acid absorber is provided throughout the nonwoven web. In embodiments, the acid absorber can be introduced into the fiber-forming material during processing so that the acid absorber is contained in the fiber itself.

In embodiments, the water-soluble nonwoven web may further comprise an antioxidant, such as a chloride scavenger. For example, suitable antioxidants/chloride scavengers include sulfite, bisulfite, thiosulfate, thiosulfate, iodide, nitrite, carbamate, ascorbate, and combinations thereof. In embodiments, the antioxidant is selected from propyl gallate (PGA), gallic acid, citric acid (CA), sodium metabisulfite (SMBS), carbamate, ascorbate, and combinations thereof. In embodiments, the antioxidant is selected from the group consisting of sodium metabisulfite, propyl gallate, gallic acid, phenolic compounds, sterically hindered amines, citric acid, zinc acetate, and combinations thereof. In embodiments, the antioxidant may be selected from the group consisting of propyl gallate, gallic acid, phenolic compounds, sterically hindered amines, sodium metabisulfite, zinc acetate, and a combination thereof. The antioxidant may be included in the nonwoven web in an amount of from about 0.25 to about 10 PHR, such as about 0.25 PHR, about 1 PHR, about 1.5 PHR, about 2 PHR, about 3 PHR, about 4 PHR, about 5 PHR, about 5.5 PHR, about 6 PHR, about 6.5 PHR, about 7 PHR, about 8 PHR, about 9 PHR, or about 10 PHR. In embodiments, the antioxidant may be included in the nonwoven web in an amount of from about 2 to about 7 PHR.

In embodiments, the antioxidant can be provided in or on the fiber, in or on the nonwoven web, or both. In embodiments, the antioxidant can be applied to the fiber, the nonwoven web, or both. In embodiments, the antioxidant can be dispersed throughout the nonwoven web. The antioxidant can be adsorbed by the fibers throughout the nonwoven web or bound by static forces. For example, the antioxidant can be added during fiber placement so that the acid scavenger is provided throughout the nonwoven web. In embodiments, the antioxidant can be introduced into the fiber-forming material during processing so that the acid scavenger is contained in the fiber itself.

In embodiments, the water-soluble nonwoven web may further comprise a filler, such as a filler selected from the group consisting of high amylose starch, amorphous silica, hydroxyethyl starch, and combinations thereof. The filler may be located in or on the fiber, in or on the nonwoven web, or within or on both, as described herein for acid absorbers and antioxidants. In embodiments, the filler may be applied to the fiber, to the nonwoven web, or to both. In embodiments, the filler may be distributed throughout the nonwoven web. The filler may be adsorbed by the fibers throughout the nonwoven web or bound by static forces. In embodiments, the filler may be provided in the fiber-forming material.

The plurality of water-soluble fibers may be produced by any method known in the art, such as wet-cooled gel spinning, thermoplastic fiber spinning, melt blowing, spun bonding, electrospinning, rotational molding, continuous filament manufacturing operations, fiber tow manufacturing operations, and combinations thereof. In embodiments, the fibers include water-soluble fibers produced by wet-cooled gel spinning, melt blowing, spun bonding, or a combination thereof. In embodiments, the fibers include water-soluble fibers that are spun from wet-cooled gel and carded into nonwoven webs.

In the art, it is common to refer to fibers and nonwoven webs by the process used to produce them. Thus, any reference herein to, for example, a "meltblown fiber" or a "carded nonwoven fabric" should not be understood as limiting the product to the process of a particular meltblown method or carding method, but rather simply as identifying a particular fiber or fabric. Thus, process terms may be used to distinguish fibers and/or nonwovens without limiting said fiber and/or nonwoven fabric to being produced by any particular process.

The fibers of the present invention may be bicomponent fibers. As used herein, unless otherwise specified, the term "bicomponent fibers" does not refer to a fiber comprising a mixture of fiber-forming materials, but rather to fibers comprising two or more separate regions of fiber-forming materials, wherein the composition of the fiber-forming materials varies by region. Examples of bicomponent fibers include, but are not limited to, core/sheath bicomponent fibers, "island-in-the-sea" bicomponent fibers, and "side-by-side" bicomponent fibers. Core/sheath bicomponent fibers typically include a core comprising a first composition of fiberizing materials (e.g., a single fiberizing material or a first mixture of fiberizing materials) and a sheath comprising a second composition of fiberizing materials (e.g., a single fiberizing material that is different from the core material, or a second mixture of fiberizing materials that is different from the first mixture of fiberizing materials of the core). "Island in the sea" bicomponent fibers typically include a first continuous "sea" region having a first composition of fiberizing materials and discrete "island" regions dispersed therein having a second composition of fiberizing materials that is different from the first composition. Bicomponent fibers arranged side by side typically include a first region extending along the length of the fiber and including a first composition of fiber-forming materials adjacent to at least a second region extending along the length of the fiber and including a second composition of fiber-forming materials that differs from the first composition. Such bicomponent fibers are well known to those skilled in the art.

The fiber shape is not particularly limited and may have cross-sectional shapes including, but not limited to, round, oval (also called a ribbon), triangular (also called a delta), trilobal and/or other multi-lobal shapes (Fig. 1). It is understood that the fiber shape need not be perfectly geometric, for example, a fiber having a circular cross-sectional shape need not have a perfect circle as a cross-sectional area, and a fiber having a triangular cross-sectional shape typically has rounded corners. Without wishing to be bound by theory, it is believed that hygroscopic fibers in a nonwoven fabric that are shaped to provide capillary or channel-directed fluid passage (e.g., trilobal fiber) can promote wicking/wicking of fluid from the surface of the nonwoven fabric, providing improved fluid absorption compared to an identical nonwoven fabric having a fiber shape that does not include a capillary or channel channel.

It should be understood that the diameter of the fiber refers to the diameter of the cross-section of the fiber along the longest axis of the cross-section. When a fiber is described as having (or not having) a certain diameter, unless otherwise indicated, it is understood that the said diameter is an average diameter for a certain type of said fiber, i.e., a plurality of fibers made from polyvinyl alcohol, the material-forming fiber, has an arithmetic average fiber diameter over the plurality of fibers. For shapes that are not generally considered to have a "diameter", such as a triangle or a multi-lobed shape, the diameter refers to the diameter of a circle describing the shape of the fiber (Fig. 1).

The fibers of the present invention typically have a diameter in the range of about 10 microns to 300 microns, such as at least 10 microns, at least 15 microns, at least 20 microns, at least 25 microns, at least 50 microns, at least 100 μm or at least 125 μm and up to about 300 μm, up to about 275 μm, up to about 250 μm, up to about 225 μm, up to about 200 μm, up to about 100 μm, up to about 50 microns, up to about 45 microns, up to about 40 microns or up to about 35 microns, such as in the range of about 10 microns to about 300 microns, about 50 microns to about 300 microns, about 100 microns to about 300 microns, about 10 to about 50 microns, about 10 to about 45 microns or from about 10 to about 40 microns. In embodiments, the water-soluble fibers used to make the water-dispersible nonwoven webs of the present invention can have a diameter of greater than 100 microns to about 300 microns. In embodiments, the fibers comprise cellulose having a diameter in the range of from about 10 microns to about 50 microns, from about 10 microns to about 30 microns, from about 10 microns to about 25 microns, from about 10 microns to about 20 microns, or from about 10 microns to about 15 microns. In embodiments, the fibers comprise a water-soluble fiber-forming material and have a diameter of about 50 microns to about 300 microns, about 100 microns to about 300 microns, about 150 microns to about 300 microns, or about 200 microns to about 300 microns. In embodiments, the diameters of a plurality of water-soluble fibers used to make the water-dispersible nonwoven webs of the present invention have substantially the same diameters. As used herein, the fiber diameter is "substantially uniform" if the difference in diameter between the fibers is less than 10%, such as 8% or less, 5% or less, 2% or less, or 1% or less. Fibers having substantially the same diameters can be produced by a wet-chill gel spinning process or a thermoplastic fiber spinning process, as described herein. Additionally, when using a blend of fibers, the average fiber diameter can be determined using the weighted average of the individual fibers.

The fibers of the present invention used to produce nonwoven webs and nonwoven composite articles of the present invention can generally have any length. In embodiments, the length of the fibers can be in the range of from about 20 mm to about 100 mm, from about 20 mm to about 90 mm, from about 30 mm to about 80 mm, from about 10 mm to about 60 mm, or from about 30 mm to about 60 mm, such as at least about 30 mm, at least about 35 mm, at least about 40 mm, at least about 45 mm, or at least about 50 mm, and up to about 100 mm, up to about 95 mm, up to about 90 mm, up to about 80 mm, up to about 70 mm, or up to about 60 mm. In embodiments, the length of the water-soluble fibers can be less than about 30 mm or in the range from about 0.25 mm to less than about 30 mm, such as at least about 0.25 mm, at least about 0.5 mm, at least about 0.75 mm, at least about 1 mm, at least about 2.5 mm, at least about 5 mm, at least about 7.5 mm or at least about 10 mm and up to about 29 mm, up to about 28 mm, up to about 27 mm, up to about 26 mm, up to about 25 mm, up to about 20 mm or up to about 15 mm. The fibers can be of any length by cutting and/or twisting the extruded polymer mixture. In embodiments, the fiber may be a continuous filament, such as produced by processes such as spunbond, melt blowing, electrospinning, and rotary spinning, wherein the continuous filament is produced and fed directly into the web form. In addition, when using a blend of fibers, the average length of the fibers may be determined using a weighted average of the individual fibers.

The fibers of the present invention can generally have any aspect ratio. In embodiments, the aspect ratio of the fibers can be greater than about 2, greater than about 3, greater than about 4, greater than about 6, greater than about 10, greater than about 50, greater than about 60, greater than about 100, greater than about 200, greater than about 300, greater than about 400, or greater than about 1000.

The water-soluble fibers used to make the water-soluble nonwoven fabrics of the present invention can generally have any specific strength (breaking load). The specific strength of a fiber correlates with the coarseness of the fiber. As the breaking load of a fiber decreases, its roughness increases. The fibers used to make the water-soluble nonwoven webs of the present invention can have a tenacity in the range of from about 1 to about 100 cN/dtex, or from about 1 to about 75 cN/dtex, or from about 1 to about 50 cN/dtex, or from about 1 to about 45 cN/dtex, or from about 1 to about 40 cN/dtex, or from about 1 to about 35 cN/dtex, or from about 1 to about 30 cN/dtex, or from about 1 to about 25 cN/dtex, or from about 1 to about 20 cN/dtex, or from about 1 to about 15 cN/dtex, or from about 1 to about 10 cN/dtex, or from about 3 to about 8 cN/dtex, or from about 4 to about 8 cN/dtex, or from about 6 to about 8 cN/dtex, or from about 4 to about 7 cN/dtex, or from about 10 to about 20, or from about 10 to about 18, or from about 10 to about 16, or from about 1 cN/dtex, about 2 cN/dtex, about 3 cN/dtex, about 4 cN/dtex, about 5 cN/dtex, about 6 cN/dtex, about 7 cN/dtex, about 8 cN/dtex, about 9 cN/dtex, about 10 cN/dtex, about 11 cN/dtex, about 12 cN/dtex, about 13 cN/dtex, about 14 cN/dtex, or about 15 cN/dtex. In embodiments, the fibers can have a specific strength of about 3 cN/dtex to about 10 cN/dtex. In embodiments, the fibers can have a specific strength of about 5 cN/dtex to about 10 cN/dtex. In embodiments, the fibers can have a specific strength of about 7 cN/dtex to about 10 cN/dtex. In embodiments, the fibers can have a specific strength of about 4 cN/dtex to about 8 cN/dtex. In embodiments, the fibers can have a specific strength of about 6 cN/dtex to about 8 cN/dtex.

The fibers used to produce the water-soluble nonwoven webs of the present invention can generally have any fineness. The fiber fineness correlates with how many fibers are present in the cross-section of a yarn of a given thickness. The fiber fineness is the ratio of the mass of the fiber to its length. The basic physical unit of fiber fineness is 1 tex, which is equal to 1000 m of fiber weighing 1 g. The unit dtex (dtex) is commonly used, representing 1 g/10,000 m of fiber. The fiber fineness can be selected to obtain a nonwoven web having suitable nonwoven web stiffness/handiness, torsional rigidity, reflection and interaction with light, absorption of dye and/or other active substances/additives, ease of spinning the fiber in the manufacturing process and uniformity of the finished product. In general, as the fiber fineness increases, the nonwoven materials obtained from them exhibit higher uniformity, improved tensile strength, extensibility and luster. In addition, without intending to be bound by any theory, it is believed that finer fibers will result in a slower dissolution time compared to larger fibers depending on the density. In addition, without intending to be bound by any theory, when using a fiber blend, the average fiber fineness can be determined using a weighted average of the individual fiber components. The fibers can be characterized as very fine (dtex ≤ 1.22), fine (1.22 ≤ dtex ≤ 1.54), medium (1.54 ≤ dtex ≤ 1.93), slightly coarse (1.93 ≤ dtex ≤ 2.32) and coarse (dtex ≥ 2.32). The nonwoven web according to the present invention can include very fine, fine, medium, slightly coarse fibers, or a combination thereof. In embodiments, the fibers have a fineness in the range of about 1 dtex to about 10 dtex, about 1 dtex to about 7 dtex, about 1 dtex to about 5 dtex, about 1 dtex to about 3 dtex, or about 1.7 dtex to about 2.2 dtex. In embodiments, the fibers have a fineness of about 1.7 dtex. In embodiments, the fibers have a fineness of about 2.2 dtex. In embodiments, the fibers include fibers with a fineness of about 1.7 dtex and fibers with a fineness of about 2.2 dtex.

Gel spinning with wet cooling method

In some embodiments, the plurality of water-soluble fibers comprise water-soluble fibers produced according to a wet-chill gel spinning process, wherein the wet-chill gel spinning process comprises the steps of

(a) dissolving a water-soluble polymer (or polymers) in a solution to form a polymer mixture, wherein the polymer mixture optionally includes auxiliary agents;

(b) extruding the polymer mixture through a rotating nozzle into a curing bath to form an extruded polymer mixture;

(c) passing the extruded polymer mixture through a solvent exchange bath;

(d) optionally wet drawing the extruded polymer mixture; and

(e) final processing of the extruded polymer mixture to obtain water-soluble fibers.

The solvent in which the water-soluble polymer is dissolved may be any solvent in which the water-soluble polymer is soluble. In embodiments, the solvent in which the water-soluble polymer is dissolved comprises a polar aprotic solvent. In embodiments, the solvent in which the water-soluble polymer is dissolved comprises dimethyl sulfoxide (DMSO).

Typically, the curing bath includes a cooled solvent for gelling the extruded polymer mixture. The curing bath can typically be any temperature that facilitates curing of the extruded polymer mixture. The curing bath can include a mixture of a solvent in which the polymer is soluble and a solvent in which the polymer is not soluble. The solvent in which the polymer is not soluble is typically the primary solvent, with the solvent in which the polymer is not soluble making up more than 50% of the mixture.

After passing through the curing bath, the extruded gel of the polymer mixture can be passed through one or more solvent exchange baths. The solvent exchange baths are designed to exchange the solvent in which the water-soluble polymer dissolves with a solvent in which the water-soluble polymer does not dissolve, for further curing the extruded polymer mixture and to exchange the solvent in which the water-soluble polymer dissolves with a solvent that evaporates more easily, thereby reducing the drying time. The solvent exchange baths can include a series of solvent exchange baths having a gradient of a solvent in which the water-soluble polymer dissolves with respect to a solvent in which the water-soluble polymer does not dissolve, a series of solvent exchange baths containing only the solvent in which the water-soluble polymer does not dissolve, or a single solvent exchange bath containing only the solvent in which the water-soluble polymer does not dissolve. In embodiments, at least one solvent exchange bath can consist essentially of a solvent in which the water-soluble polymer does not dissolve.

The finished fibers are sometimes called staple fibers, short fibers, or pulp. In embodiments, finishing includes drying the extruded polymer mixture. In embodiments, finishing includes cutting or twisting the extruded polymer mixture to form individual fibers. Wet drawing of the extruded polymer mixture ensures that the extruded polymer mixture and, thus, the fibers cut from it have a substantially uniform diameter. Drawing differs from extrusion, as is well known in the art. In particular, extrusion refers to the process of making fibers by forcing a resin mixture through a die head, while drawing refers to mechanically drawing fibers in the machine direction to provide polymer chain orientation and crystallization to increase the strength (tensile) and strength (breakage) of the fiber.

In embodiments in which the water-soluble fibers are produced by a wet-chill gel spinning process, the water-soluble polymer can be, in general, any water-soluble polymer or mixture thereof, such as two or more different polymers, as generally described herein. In further details of the above embodiment, the polymer(s) may have any degree of polymerization (DP), such as in the range of from 10 to 10,000,000, such as at least 10, at least 20, at least 50, at least 100, at least 200, at least 300, at least 400, at least 500, at least 750 or at least 1000 and up to 10,000,000, up to 5,000,000, up to 2,500,000, up to 1,000,000, up to 900,000, up to 750,000, up to 500,000, up to 250,000, up to 100,000, up to 90,000, up to 75,000, up to 50,000, up to 25,000, up to 12,000, up to 10,000, up to 5,000 or up to 2,500, such as in the range of from 1,000 to about 50,000, from 1,000 to about 25,000, from 1,000 to about 12,000, from 1,000 to about 5,000, from 1,000 to about 2,500, from about 50 to about 12,000, from about 50 to about 10,000, from about 50 to about 5,000, from about 50 to about 2,500, from about 50 to about 1,000, from about 50 to about 900, from about 100 to about 800, from about 150 to about 700, from about 200 to about 600 or from about 250 to about 500. In embodiments, the DP is at least 1000. Auxiliary agents, as described above, can be added to the fibers themselves or to the nonwoven web during the carding and/or bonding process.

Spinning of thermoplastic fibers

Spinning of thermoplastic fibers is well known in the art. Briefly, spinning of thermoplastic fiber involves the following steps:

(a) preparing a polymer mixture comprising a fibre-forming polymer, optionally comprising auxiliary substances;

(b) extruding the polymer mixture through a die to form an extruded polymer mixture;

(c) optionally stretching the extruded polymer mixture; and

(d) final processing of the extruded polymer mixture to obtain fibers.

The finished staple fibers produced by the thermoplastic fiber spinning process may be processed by drying, cutting, and/or twisting to form individual fibers. Extruding the extruded polymer mixture mechanically draws the fibers in the machine direction, promoting orientation and crystallinity of the polymer chains to increase the tenacity and strength of the fibers. Preparing the polymer mixture for forming thermoplastic fibers may typically involve (a) preparing a solution of a fiber-forming material and a highly volatile solvent such that after extruding the solution through a spinneret, when the solution is contacted with a stream of hot air, the solvent readily evaporates, leaving behind solid fibers, or (b) melting the polymer such that after extruding the hot polymer through a spinneret, the polymer solidifies due to cooling with cold air. The thermoplastic fiber spinning method differs from the wet-cooled gel spinning method at least in that (a) in the thermoplastic fiber spinning method, the extruded fibers are solidified by evaporation of a solvent or quenching of hot solid fibers with cold air, rather than by using a solidification bath; and (b) in the wet and cold gel spinning method, the optional drawing is performed when the fibers are in a gel state rather than in a solid state.

The fiberizing materials for producing fibers in the spinning process of thermoplastic fibers can generally be any fiberizing polymer or a mixture thereof, such as two or more different polymers, provided that the polymer or mixture thereof has a suitable solubility in a volatile solvent and / or has a melting point below and different from their decomposition temperature. In addition, when a mixture of fiberizing polymers is used to produce a fiber, the fiberizing materials must have the same solubility in a volatile solvent and / or have similar thermal profiles so that two or more fiberizing materials melt at the same temperatures. In contrast, fiberizing materials for producing fibers from a wet-cooled gel spinning process are not so limited, and the fibers can be obtained from a mixture of any two or more polymers soluble in the same solvent system, and the solvent system does not necessarily have to be the only solvent or even a volatile solvent.

The fiber-forming polymer(s) for producing thermoplastic fibers may have a degree of polymerization (DP) of, for example, in the range of 10 to 10,000, such as at least 10, at least 20, at least 50, at least 100, at least 200, at least 300, at least 400, at least 500, at least 750 or at least 1000 and up to 10,000, up to 5,000, up to 2,500, up to 1,000, up to 900, up to 750, up to 500 or up to 250. In embodiments, the DP is less than 1000.

Melt spinning

Melt spinning is well known in the art and is understood to refer to both spun bond and melt blown processes. Melt spinning is a continuous process in which the nonwoven web is produced directly during the fiber formation process. As such, the melt spun fibers are not processed or cut to any constant length (for example, staple fibers are not produced by these processes). In addition, melt spinning does not involve a drawing step and, therefore, the only control over the diameter of the resulting melt spun fibers is the size of the holes through which the fiber-forming materials are extruded, and the polymer chains are generally not oriented in any particular direction.

In brief, melt spinning involves the following steps:

(a) preparing a polymer mixture comprising a fibre-forming polymer, optionally comprising auxiliary substances;

(b) extruding the polymer mixture into an extrusion die to form an extruded polymer mixture;

(c) quenching of the extruded polymer mixture;

(d) applying the hardened extruded polymer mixture to the tape to form a nonwoven web; and

(e) bonding of nonwoven fabric.

In the spunbond process, the extruded polymer mixture is pumped into a die as molten polymer and is cooled by cold air after passing through the die. In the melt blown process, the extruded polymer mixture is pumped into a die through which hot air is blown and is cooled after exiting the die and coming into contact with air at ambient temperature. In both processes, the fibers are continuously dropped onto a belt or drum, which is usually facilitated by applying a vacuum beneath the belt or drum.

The diameter of the melt-spun fibers is typically in the range of from about 0.1 to about 50 μm, such as at least about 0.1 μm, at least about 1 μm, at least about 2 μm, at least about 5 μm, at least about 10 microns, at least about 15 microns, or at least about 20 microns, and up to about 50 microns, up to about 40 microns, up to about 30 microns, up to about 25 microns, up to about 20 microns, up to about 15 μm, up to about 10 μm, from about 0.1 μm to about 50 μm, from about 0.1 μm to about 40 μm, from about 0.1 μm to about 30 μm, from about 0.1 μm to about 25 μm, from about 0.1 μm to about 20 μm, from about 0.1 μm to about 15 μm, from about 0.1 μm to about 10 µm, from about 0.1 µm to about 9 µm, from about 0.1 µm to about 8 µm, from about 0.1 µm to about 7 µm, from about 0.1 µm to about 6 µm, from about 0.1 µm to about 6 µm, from about 5 µm to about 35 µm, from about 5 µm to about 30 µm, from about 7.5 µm to about 25 µm microns, from about 10 microns to about 25 microns, or from about 15 microns to about 25 microns. It is well known in the art that melt blowing processes can produce microfine fibers having an average diameter in the range of about 1-10 microns, however, the melt blowing process has very large variations in diameter from fiber to fiber, for example, a variation of 100-300%. Additionally, it is well known in the art that spunbond fibers can have a larger average fiber diameter, such as typically from about 15 to about 25 microns, but improved interfiber uniformity, such as about 10% variation.

The fiberizing material for thermal extrusion processes (e.g., melt spinning, thermoplastic fiber spinning) is more limited than for the wet-cooled gel spinning process. Typically, the degree of polymerization for thermal extrusion processes is limited to a range of about 200 to about 500. As the degree of polymerization decreases below 200, the viscosity of the fiberizing material becomes too low, and the individual fibers obtained by pumping the material through a die set-up do not maintain proper separation after exiting the die set-up. Likewise, as the degree of polymerization increases above 500, the viscosity becomes too high to effectively pump the material through small enough holes in the die set-up to carry out the process at high speeds, resulting in a loss of process efficiency and fiber and/or nonwoven fabric uniformity. In addition, processes requiring heating of the fiber-forming material are not suitable for polyvinyl alcohol homopolymers, since homopolymers generally do not have the required thermal stability.

The wet-chill gel spinning process advantageously provides one or more of the advantages of producing a fiber that includes a blend of water-soluble polymers, providing control over the diameter of the fibers, providing fibers of relatively large diameter, providing control over the length of the fiber, providing control over the breaking load of the fibers, providing fibers with a high breaking load, providing fibers from polymers having a high degree of polymerization, and/or providing fibers that can be used to form a self-supporting nonwoven web. Continuous processes such as spunbond fiber spinning, melt blowing, electrospinning, and rotary spinning generally do not allow blending water-soluble polymers (e.g., due to difficulties in matching the melt index of different polymers), forming articles of large diameter (e.g., greater than 50 microns) fibers, controlling the length of the fibers, providing high strength fibers, and using polymers having a high degree of polymerization. In addition, the wet-cooled gel spinning process is preferably not limited to polymers that are only melt-processable and can therefore access fibers made from fiber-forming materials that have very high molecular weights, high melting points, low melt flow indexes, or a combination thereof, providing fibers that have stronger physical properties and different chemical functionalities compared to fibers produced by a thermal extrusion process. Moreover, it is preferable that the wet-cooled gel spinning process is not limited by the viscosity of the polymer. In contrast, it is known in the art that processes that require melting of the fiber-forming material are limited to fiber-forming materials that have a viscosity of 5 cP or less. Thus, fibers comprising polymers, including homopolymers and copolymers of polyvinyl alcohol, having a viscosity of more than 5 cP are accessible only by wet-cooled gel spinning.

Non-woven fabric

The nonwoven webs of the present invention are typically sheet structures having two outer surfaces, wherein the nonwoven webs include a plurality of fibers. The nonwoven webs of the present invention can be made from fibers using any methods known in the art. As is known in the art, when fibers are spun or meltblown, the fibers are continuously laid down to form a nonwoven web, followed by bonding of the fibers.

The staple fibers may be carded or airlaid and bonded to form a nonwoven web. Carding and airlaid methods are well known in the art.

Methods for bonding nonwoven webs are well known in the art. In general, bonding may include thermal, mechanical and/or chemical bonding. Thermal bonding may include, but is not limited to, film bonding, embossing, air bonding and ultrasonic bonding. Mechanical bonding may include, but is not limited to, hydroentangling (spunlace), needlepunching and stitch bonding. Chemical bonding may include, but is not limited to, solvent bonding and resin bonding.

Thermal bonding is achieved by applying heat and pressure and generally maintains the pore size, shape and alignment achieved during the carding process. Thermal bonding conditions can be readily determined by one skilled in the art. In general, if the applied heat and/or pressure is too low, the fibers will not bond sufficiently to form a freestanding web, and if the heat and/or pressure is too high, the fibers will begin to fuse together. The chemical composition of the fiber determines the upper and lower limits of temperature and/or pressure for thermal bonding. Without intending to be bound by any theory, it is believed that at temperatures above 235°C, polyvinyl alcohol fibers are destroyed. Embossing methods for thermally bonding fibers are known. Embossing can be single-sided or double-sided embossing. Typically, embossing of water-soluble fibers involves single-sided embossing using a single embossing roller consisting of an ordered circular array and a steel roller with a smooth surface. As the embossing increases (e.g., as the web is given surface features), the surface area of the web increases. Without intending to be bound by any theory, it is expected that as the surface area of the web increases, the solubility of the web also increases. Accordingly, the solubility properties of the nonwoven web can be advantageously controlled by changing the surface area through embossing.

Air bonding typically requires a high thermoplastic content in the nonwoven web and two materials with different melting temperatures. In air bonding, the unbonded nonwoven web circulates around the drum while hot air flows from the outside of the drum to the center of the drum. Air bonding produces nonwovens with low densities and higher specific grammages (e.g., from over 20 to about 2000 g/ ^m2 ). Air bonded nonwovens are typically very soft.

Chemical bonding generally includes solvent bonding and resin bonding. In particular, chemical bonding generally uses a binder solution of solvent and resin (e.g., latex or waste polymer left over from fiber manufacturing). The nonwoven fabric can be coated with the binder solution and heat and pressure are applied to cure the binder and bond the nonwoven fabric. The binder solution can be applied by dipping the nonwoven fabric in a bath of the binder solution, spraying the binder solution onto the nonwoven fabric, squeezing the binder solution onto the web (foaming), and/or applying the binder solution in the form of printing or gravure printing.

Chemical bonding can result in the formation of smaller and less ordered pores compared to carding/melt spinning pores. Without intending to be bound by theory, it is believed that if the resin solution used for chemical bonding is sufficiently concentrated and/or sufficient pressure is applied, a non-porous water-dispersible nonwoven web can be formed. The solvent used in chemical bonding causes partial dissolution of existing fibers in the web, which results in welding and bonding of the fibers to each other. Thus, in general, the solvent for chemical bonding can be any solvent that can at least partially dissolve one or more fiber-forming materials from the fibers of the nonwoven web. In embodiments, the solvent is selected from the group consisting of water, ethanol, methanol, DMSO, glycerin, and a combination thereof. In embodiments, the solvent is selected from the group consisting of water, glycerin, and a combination thereof. In embodiments, the binder solution comprises a solvent selected from the group consisting of water, ethanol, methanol, DMSO, glycerol and a combination thereof, and further comprises a resin selected from the group consisting of polyvinyl alcohol, latex and polyvinylpyrrolidone. The binder contained in the solution assists in the welding process to provide a more mechanically robust web. The temperature of the polymer solution is not particularly limited and can be provided at room temperature (about 23°C).

In some embodiments, a second layer of fibers may be used to bond the nonwoven web. In embodiments, at least one nonwoven layer of the composite articles of the present invention is bonded using a second layer of nonwoven web/fibers. In embodiments, at least two nonwoven layers of the composite articles of the present invention are bonded using an additional layer of nonwoven web/fibers. In embodiments, at least one nonwoven layer of the composite articles of the present invention is bonded using thermal, mechanical or chemical bonding alone or in addition to bonding using an additional layer of nonwoven web/fibers.

Pore sizes can be determined using high magnification surface analysis and ordering techniques including, but not limited to, Brunauer-Emmett-Teller (BET) theory, small-angle X-ray scattering (SAXS), and molecular adsorption.

Nonwoven webs can be characterized by their basis weight. The basis weight of a nonwoven web is the weight per unit area of the nonwoven web. The basis weight can be changed by changing the manufacturing conditions, as is known in the art. The nonwoven web can have the same basis weight before and after bonding. Alternatively, the bonding method can change the basis weight of the nonwoven web. For example, when bonding occurs by applying heat and pressure, the thickness of the nonwoven web (and thus the area of the nonwoven web) can be reduced, thereby increasing the basis weight. Accordingly, as used herein and unless otherwise noted, the basis weight of a nonwoven web refers to the basis weight of the nonwoven web after bonding.

The nonwoven webs of the present invention can typically have any basis weight in the range of from about 0.1 g/ ^m2 to about 700 g/ ^m2 , from about 0.5 g/ ^m2 to about 600 g/ ^m2 , from about 1 g/ ^m2 to about 500 g/ ^m2 , from about 1 g/ ^m2 to about 400 g/ ^m2 , from about 1 g/ ^m2 to about 300 g/ ^m2 , from about 1 g/ ^m2 to about 200 g/ ^m2 , from about 1 g/ ^m2 to about 100 g/ ^m2 , from about 30 g/ ^m2 to about 100 g/ ^m2 , from about 20 g/ ^m2 to about 100 g/ ^m2 , from about 20 g/ ^m2 to about 80 g/ ^m2 , or from about 25 g/ ^m2 to about 70 g/ ^m2 .

The nonwoven webs of the present invention can generally have any thickness. Suitable thicknesses can include, but are not limited to, from about 5 to about 10,000 μm (1 cm), from about 5 to about 5,000 μm, from about 5 to about 1,000 μm, from about 5 to about 500 μm, from about 200 to about 500 μm, from about 5 to about 200 μm, from about 20 to about 100 μm, or from about 40 to about 90 μm, or from about 50 to 80 μm, or from about or about 60 to 65 μm, such as 50 μm, 65 μm, 76 μm or 88 μm.

The nonwoven webs of the present invention can be characterized as webs with high elasticity (loosening) or low elasticity. In general, elasticity refers to the ratio of thickness to weight per unit area (i.e., basis weight). Highly elastic nonwoven webs can be characterized by a high ratio of thickness to weight per unit area. The term "high elasticity" as used herein refers to a nonwoven web according to the present invention having a basis weight as defined herein and a thickness exceeding 200 μm. The thickness of a nonwoven web can be determined according to ASTM D5729-97, ASTM D5736 and ISO 9073-2:1995 and can include, for example, subjecting the nonwoven web to a load of 2 N and measuring the thickness. Highly elastic materials can be used according to methods known in the art, such as through-air bonding or cross-laying, which uses a cross-laying device to fold the unbonded web onto itself to create elasticity and basis weight. Without intending to be bound by theory, unlike water-soluble nonwoven webs, where the solubility of the nonwoven web may depend on the thickness of the nonwoven web; it is believed that the solubility of the nonwoven web is independent of the thickness of the web. In this regard, it is believed that since individual fibers provide a larger surface area than a water-soluble film, regardless of the thickness of the nonwoven web, the parameter that limits the approach of water to the fibers and ultimately the dissolution of the fibers is the basis weight (i.e., the density of the fiber in the nonwoven material).

The solubility of the water-soluble nonwoven webs of the present invention generally depends on the type of fibers used to make the web, as well as on the basis weight of the water-soluble web. Without intending to be bound by any theory, it is believed that the solubility profile of the nonwoven web corresponds to the same solubility profile of the fiber(s) used to make the nonwoven web, and the solubility profile of the fiber generally corresponds to the same solubility profile of the polymer(s) from which the fiber is made. For example, for nonwoven webs containing PVOH fibers, the degree of hydrolysis of the PVOH polymer can be selected such that it also affects the solubility of the nonwoven web in water. In general, at a given temperature, as the degree of hydrolysis of the PVOH polymer increases from partially hydrolyzed (88% DH) to completely hydrolyzed (≥98% DH), the solubility of the polymer in water generally decreases. Thus, in one embodiment, the water-soluble nonwoven web may be cold water soluble. For a copoly(vinyl acetate and vinyl alcohol) polymer that does not include any other monomers (e.g., is not copolymerized with an anionic monomer), the cold water soluble web, soluble in water at a temperature of less than 10 ^o C, may include PVOH fibers with a degree of hydrolysis in the range of from about 75% to about 90%, or in the range of from about 80% to about 90%, or in the range of from about 85% to about 90%. In another embodiment, the water-soluble nonwoven web may be hot water soluble. For a copoly(vinyl acetate and vinyl alcohol) polymer that does not include any other monomers (e.g., is not copolymerized with an anionic monomer), the hot water soluble web, soluble in water at a temperature of at least about 60 ^o C, may include PVOH fibers with a degree of hydrolysis of at least about 98%.

Modification of PVOH generally increases the solubility of the PVOH polymer. Thus, at a given temperature, the solubility of a water-soluble nonwoven web obtained from a PVOH copolymer is expected to be higher than the solubility of a nonwoven web obtained from a PVOH homopolymer having the same degree of hydrolysis as the PVOH copolymer. Following these trends, a water-soluble nonwoven web having specific solubility characteristics can be developed by blending polymers with fibers and/or fibers with a nonwoven web.

In addition, as the basis weight of the web increases, the rate of dissolution of the web decreases, provided that the fiber composition remains constant, since there is more material to dissolve. For example, at a given temperature, a water-soluble web made from fibers containing PVOH polymer(s) and having a basis weight of, for example, 40 g/m ² , is expected to dissolve more slowly than an otherwise identical water-soluble web having a basis weight of, for example, 30 g/m ² . Accordingly, the basis weight can also be used to change the solubility characteristics of a water-soluble nonwoven web. The water-soluble nonwoven web may typically have any basis weight in the range of from about 1 g/ ^m2 to about 700 g/ ^m2 , from about 1 g/ ^m2 to about 600 g/ ^m2 , from about 1 g/ ^m2 to about 500 g/ ^m2 , from about 1 g/ ^m2 to about 400 g/ ^m2 , from about 1 g/ ^m2 to about 300 g/ ^m2 , from about 1 g/ ^m2 to about 200 g/ ^m2 , from about 10 g/ ^m2 to about 100 g/ ^m2 , from about 30 g/ ^m2 to about 100 g/ ^m2 , from about 20 g/ ^m2 to about 100 g/ ^m2 , from about 20 g/ ^m2 to about 80 g/ ^m2 , from about 25 g/ ^m2 to about 70 g/ ^m2 or about 40 g/ ^m2 to about 60 g/ ^m2 .

Without intending to be bound by any theory, it is believed that the solubility (in terms of time to complete dissolution) of a water-soluble nonwoven web should be superior to that of a water-soluble film of the same size (L x W) and/or mass made from the same PVOH polymer. This is due to the larger surface area of the nonwoven web compared to the film, which results in faster dissolution. As shown in the examples below, a nonwoven web made from a PVOH homopolymer with a degree of hydrolysis of 88% dissolves in 14 seconds, while a water-soluble film of the same size made from the same PVOH homopolymer with a degree of hydrolysis of 88% dissolves in approximately 100 seconds.

The specific tenacity of the water-soluble nonwoven web may be the same or different from the tenacity of the fibers used to make the web. Without intending to be bound by theory, it is believed that the specific tenacity of the nonwoven web is related to the strength of the nonwoven web, with a higher specific tenacity providing a higher strength of the nonwoven web. In general, the strength of the nonwoven web can be changed by using fibers having different specific tenacity. The specific tenacity of the nonwoven web may also depend on the processing. In general, the water-soluble webs according to the present invention have a relatively high elongation at break, i.e., the water-soluble nonwoven web is a self-supporting web that can be used as the only material for making an article and/or a bag. In contrast, nonwoven webs produced by meltblown, electrospun and/or rotary spun processes typically have low elongation at break and may not be self-supporting or suitable for use as a sole web to form an article or package.

Typically, the coefficient of dynamic friction and the ratio of the coefficient of static friction to the coefficient of dynamic friction for the water-soluble nonwoven web of the present invention will be lower than the coefficient of dynamic friction and the ratio of the coefficient of static friction to the coefficient of dynamic friction for the water-soluble film due to the increased surface roughness of the nonwoven web compared to the water-soluble film, which provides less surface contact with the nonwoven web. Advantageously, this surface roughness can provide an improved feel for the consumer (i.e., a fabric-like feel instead of a rubbery feel), an improved aesthetic appearance (i.e., less glossy than the water-soluble film) and/or facilitate processability in the manufacture of thermoformed and/or vertically formed, filled and sealed and/or multi-chamber bags that require stretching the web along the surface of the processing equipment/mold. Accordingly, the fibers must be coarse enough to provide a rough surface finish to the resulting nonwoven fabric, but not so coarse as to create resistance.

The water-soluble nonwoven web of the present invention can be used as a single layer or can be laminated with other water-soluble nonwoven webs, or can be in the form of a laminate with a water-soluble film. In some embodiments, the water-soluble nonwoven material includes a single layer of water-soluble nonwoven material. In some embodiments, the water-soluble nonwoven material is a multilayer water-soluble nonwoven material comprising two or more layers of water-soluble nonwoven materials. One or more layers can be laminated to each other. In improvements of the previous embodiment, two or more layers can be the same (for example, made of the same fibers and the same body weight). In improvements of the previous embodiment, two or more layers can be different (for example, made of different types of fibers and/or have a different basis weight).

Generally, a multi-layer water-soluble nonwoven fabric may have a basis weight that is the sum of the basis weights of the individual layers. Accordingly, it will take longer for a multi-layer water-soluble nonwoven fabric to dissolve than any of the individual layers made as a single layer.

In embodiments, the water-soluble nonwoven web of the present invention has a disintegration time of no more than 300 seconds according to MSTM 205 in water at 23°C after exposure to a TCCA, SBS or calcium hypochlorite composition for 6 or 8 weeks, under ambient conditions of 38°C and 80% relative humidity.

In embodiments, the surface area of the nonwoven web residue after testing in accordance with MSTM 205 in water at 23°C after exposure to a TCCA, SBS or calcium hypochlorite composition for 6 or 8 weeks at 38°C and 80% relative humidity under ambient conditions is less than about 50% of the surface area of the nonwoven web before testing in accordance with MSTM 205.

In embodiments, the nonwoven web retains a b* value of no more than 3.5, or no more than 3.0, or no more than 2.5 after exposure to a TCCA, SBS, or calcium hypochlorite composition for 6 or 8 weeks at a temperature of 38°C, and at and a relative humidity of 80% under ambient conditions. In embodiments, the nonwoven web retains a b* value of no more than 3.5 after exposure to a TCCA, SBS, or calcium hypochlorite composition for 6 or 8 weeks under ambient conditions of 38°C and a relative humidity of 80%. In embodiments, the nonwoven web retains a b* value of no more than 3.0 after exposure to a TCCA, SBS, or calcium hypochlorite composition for 6 or 8 weeks at 38°C and a relative humidity of 80% under ambient conditions. In embodiments, the nonwoven web maintains a b* value of no more than 2.5 after exposure to a TCCA, SBS, or calcium hypochlorite composition for 6 or 8 weeks at 38°C and 80% relative humidity under ambient conditions.

Further, the present document provides a water-soluble single-dose article comprising a water-soluble nonwoven web as described herein, in the form of a bag having an outer wall, wherein the outer wall has an outer surface, and the inner surface defines an inner volume of the bag, and a composition contained in the inner volume of the bag. In embodiments, the composition may contain an aggressive chemical. In embodiments, the aggressive chemical may contain an acid, an oxidizer, a base, or a composition thereof. In embodiments, the aggressive chemical may contain an acid. In embodiments, the aggressive chemical may contain an oxidizer. In embodiments, the aggressive chemical may contain a base.

Also provided herein is a single dose article comprising a pouch comprising an outer wall, wherein the outer wall has an outer surface, and the inner surface defines an inner volume of the pouch, wherein the outer wall comprises a nonwoven web comprising a plurality of fibers comprising a fiber-forming material of sulfonate-modified PVOH comprising a sulfonated anionic monomer unit; wherein the fiber-forming material of sulfonate-modified PVOH has a degree of hydrolysis of at least 95%, and the sulfonated anionic monomer is present in an amount in the range of from about 1 mol.% to about 5 mol.%; and a composition contained in the inner volume of the pouch. In embodiments, the composition may comprise an aggressive chemical. In embodiments, the aggressive chemical may comprise an oxidizing agent, a base, or a composition thereof. In embodiments, the aggressive chemical may comprise an oxidizing agent. In embodiments, the oxidizing agent is a base-mediated oxidizing agent. In embodiments, the indirect oxidizer-based oxidizer may comprise calcium hypochlorite.

Also provided herein is a single dose article comprising a bag comprising an outer wall, wherein the outer wall has an outer surface, and the inner surface defines an inner volume of the bag, wherein the outer wall comprises a nonwoven web comprising a plurality of fibers comprising (i) polyvinylpyrrolidone and (ii) polyvinyl alcohol (PVOH) modified with a sulfonate, PVOH modified with a carboxyl group, or both; and a composition contained in the inner volume of the bag. In embodiments, the composition may comprise an aggressive chemical. In embodiments, the aggressive chemical may comprise an acid, an oxidizing agent, a base, or a composition thereof. In embodiments, the aggressive chemical may comprise an acid. In embodiments, the aggressive chemical may comprise an oxidizing agent. In embodiments, the aggressive chemical may comprise a base.

In some embodiments, the aggressive chemical may comprise one or more of hypochlorite, hypochlorous acid, halogenated isocyanurate, chlorate, chlorite, perchlorate, bromate, perbromate, halogenated hydantoin, perborate, periodate, persulfate, permanganate, chromate, dichromate, nitrate, nitrite, peroxide, ketone peroxide, peroxy acid, citric acid, hydrochloric acid, and an inorganic acid such as one or more of sodium bisulfate (SBS), cyanuric acid, dichloroisocyanuric acid, trichloroisocyanuric acid (TCCA), and calcium hypochlorite. In embodiments, the compositions may be both an acid and an oxidizing agent such as trichloroisocyanuric acid. In embodiments, the aggressive chemical may comprise hypochlorite. In embodiments, the aggressive chemical may comprise calcium hypochlorite.

In some embodiments, the aggressive chemical may include a chlorine-releasing compound. In embodiments, the acid, oxidizer, base, or combination thereof may comprise a chlorine-releasing compound. As used herein, the term "chlorine-releasing compound" refers to a family of chemicals that release chlorine or chloride upon contact with water. Chlorine-releasing compounds are widely used as bleaching materials, water disinfectants, medical equipment disinfectants, and other disinfectant applications.

In one embodiment, for example, the oxidizing agent can include hypochlorous acid, hypochlorite, a halogenated isocyanurate such as sodium dichloroisocyanurate, chlorate, chlorite, perchlorate, bromate, perbromate, halogenated hydantoin, perborate, periodate, persulfate, permanganate, chromate, dichromate, nitrate, nitrite, peroxide, ketone peroxide, peroxy acid, inorganic acid, or a combination thereof. In embodiments, the oxidizing agent includes trichloroisocyanuric acid. In embodiments, the oxidizing agent can include trichloroisocyanuric acid (TCCA), dichloroisocyanuric acid (DCCA), 1-bromo-3-chloro-5,5-dimethylhydantoin (BCDMH), calcium hypochlorite (Cal-Hypo), potassium peroxymonosulfate (MPS). In embodiments, the aggressive chemical may comprise a base-mediated oxidizing agent. In embodiments, the base-mediated oxidizing agent may comprise hypochlorite. In embodiments, the base-mediated oxidizing agent may comprise calcium hypochlorite. In embodiments, the aggressive chemical may comprise an acid-mediated oxidizing agent. As used herein, the term "acid-mediated oxidizing agent" refers to an oxidizing agent that oxidizes other chemical compounds using an acidic mechanistic oxidation pathway, such as that shown in Scheme 2. In general, an acid-mediated oxidizing agent includes any oxidizing compound, including an acid-stabilizing molecule. In embodiments, the acid-mediated oxidizing agent may comprise TCCA, DCCA, BCDMH, or combinations thereof. In embodiments, the acid-mediated oxidizing agent may comprise a halogenated isocyanurate. In embodiments, the acid-mediated oxidizing agent may comprise TCCA, DCCA, or a combination thereof. In embodiments, the acid-mediated oxidizing agent may comprise BCDMH.

Scheme 2 – Three acid-mediated pathways for PVOH oxidation

1. Condensation reaction

2. Crosslinking

3. Oxidative Formation of Ketones

Crosslinking – Cross-linking

Oxidative Formation of Ketones

It has been advantageously found that single dose articles as disclosed herein can have unexpected selective resistance to base-mediated oxidants compared to acid-mediated oxidants. For example, a nonwoven web comprising fibers comprising a nonwoven web of AMPS-modified PVOH when exposed to TCCA (an acid-mediated oxidant) or calcium hypochlorite (a base-mediated oxidant) alone for 2, 4, and 6 weeks at 38°C and 80% RH, under ambient conditions, showed very different results. Although both TCCA and calcium hypochlorite are oxidants, the nonwoven web comprising AMPS-modified PVOH showed good results when exposed to calcium hypochlorite and did not show the same good properties when exposed to TCCA. In particular, when exposed to calcium hypochlorite for 6 weeks in an atmosphere of 38°C and 80% RH, under ambient conditions, the nonwoven fabric maintained acceptable disintegration (e.g., 100% disintegration in less than 300 seconds) according to the dissolution, disintegration and % residue test (MSTM 205), discolouration resistance according to the CIELab test (e.g., b* value less than 3) and maintained acceptable % elongation according to the elongation test (e.g., less than 15%). However, a nonwoven fabric with the same composition, when exposed to TCCA for only 2 weeks at 38°C and 80% RH, under ambient conditions, demonstrated unacceptable disintegration (e.g., disintegration takes greater than 300 seconds) according to MSTM 205, demonstrated unacceptable discoloration (e.g., b* value greater than 3), and also demonstrated unacceptable % elongation (e.g., greater than 15%). Without wishing to be bound by theory, it is believed that the different mechanistic pathways of each oxidant provide different performance results.

In some embodiments, the acid may include acids having a pH in the range of -2 to 6.5 in a 1% aqueous solution, or -1 to 6 in a 1% aqueous solution, or 0 to 5 in a 1% aqueous solution, or 1 to 5 in a 1% aqueous solution, or 1 to 4 in a 1% aqueous solution. In embodiments, the acid may include sodium bisulfate, cyanuric acid, dichloroisocyanuric acid, trichloroisocyanuric acid, citric acid, hydrochloric acid, or a combination thereof. In embodiments, the acid may include sodium bisulfate, cyanuric acid, dichloroisocyanuric acid, trichloroisocyanuric acid, or a combination thereof.

In some embodiments, the base may include sodium carbonate, sodium bicarbonate, or a combination thereof.

In embodiments, the water-soluble single-dose product may comprise a composition that is not intended for home care. The non-home care composition may be selected from agricultural compositions, aviation compositions, food and nutritional compositions, industrial compositions, livestock compositions, marine compositions, medical compositions, commercial compositions, military and paramilitary compositions, office compositions, recreational and park compositions, pet compositions, a liquid and/or water layer treatment composition, and a combination thereof. In embodiments, the non-home care composition is a liquid and/or water layer treatment composition.

In embodiments, the water-soluble single-dose article may contain an aggressive chemical composition comprising a concentration of an acid, an oxidizer, a base, or a combination thereof in the range of 50 wt.% to 100 wt.%, or 60 wt.% to 100 wt.%, or 70 wt.% to 100 wt.%, or 80 wt.% to 100 wt.%, or 90 wt.% to 100 wt.%, based on the total weight of the composition. In embodiments of the invention, the concentration of the acid, oxidizer, base or combination thereof in the composition for care of non-household products of the water-soluble standard dosed product is in the range from 50 wt.% to 100 wt.% or from 60 wt.% to 100 wt.% or from 70 wt.% to 100 wt.%, or from 80 wt.% to 100 wt.%, or from 90 wt.% to 100 wt.%, based on the total weight of the non-household care composition.

In embodiments, the bag may further comprise a first coating comprising an acid absorber and/or an antioxidant, wherein the first coating is in contact with the water-soluble nonwoven web. In embodiments, the first coating comprising an acid absorber, an antioxidant, or a combination thereof may be applied to at least a portion of the inner surface of the outer wall. In embodiments, the first coating comprising an acid absorber, an antioxidant, or a combination thereof may be applied to at least a portion of the outer surface of the outer wall. In embodiments, the bag further comprises a second coating comprising an acid absorber, an antioxidant, or both. In embodiments, the first coating is applied to at least a portion of the inner surface of the outer wall, and the second coating is applied to at least a portion of the outer surface of the bag.

The first and/or second coating of the water-soluble single-dose article described herein may be applied to the outer wall using any suitable method known in the art, for example, solution coating such as spin coating, dip coating, brush coating, and spray coating.

The acid scavenger and/or antioxidant provided in the first and/or second coating may be any acid scavenger and/or antioxidant described herein. In embodiments, the acid scavenger comprises N-vinylpyrrolidone, sodium metabisulfite, zinc oxide, hydrotalcite, metal stearate, activated olefins, allyl compounds, carboxylate compounds, ethylene-containing compounds, quaternary ammonium compounds, tertiary amine-containing compounds, and a combination thereof. In embodiments, the antioxidant comprises propyl gallate, gallic acid, phenolic compounds, hindered amines, sodium metabisulfite, zinc acetate, and a combination thereof.

In addition, a water-soluble single-dose article is proposed, comprising a water-soluble nonwoven fabric according to the invention in the form of a bag having an outer wall having an outer surface and an inner surface defining an inner volume of the bag and a liquid layer and/or a water treatment composition contained in the inner volume of the bag, the concentration of an aggressive chemical compound in the liquid layer and/or the water treatment composition being in the range from 50% to 100% by weight, and wherein the bag optionally includes a first coating containing an acid absorber provided on at least a portion of the inner surface of the outer wall.

In embodiments, the single dose article disclosed herein comprises a plurality of fibers comprising a sulfonate-modified PVOH fiber-forming material comprising a sulfonate-modified PVOH fiber-forming material having a hydrolysis degree of at least 95% and the sulfonated anionic monomer unit being present in an amount in the range of about 1 mole % to about 5 mole %, may include a liquid and/or water layer treatment composition contained in the interior volume of the bag, the liquid and/or water layer treatment composition may comprise calcium hypochlorite in an amount of 50% to 100% by weight of the liquid layer and/or water treatment composition. In embodiments, the bag comprises a first coating comprising an acid absorbent applied to at least a portion of the inner surface of the outer wall.

In embodiments of the invention, a single dose article disclosed herein comprising a plurality of fibers comprising a mixture of fiber-forming materials comprising (i) polyvinylpyrrolidone and (ii) PVOH modified with a sulfonate, PVOH modified with a carboxyl group, or both, may comprise a composition for treating a liquid and/or water layer contained in the interior volume of the bag, the composition for treating a liquid and/or water layer may comprise calcium hypochlorite in the range of 50% to 100% by weight of the weight of the liquid layer and/or the water treatment composition. In embodiments, the bag comprises a first coating comprising an acid absorbent applied to at least a portion of the inner surface of the outer wall.

Furthermore, the present document provides a method for dispensing a composition from a large amount of water, comprising the steps of contacting a water-soluble article in a single dose as described herein with a large amount of water, thereby dissolving at least a portion of the water-soluble nonwoven web and releasing the composition in a large amount of water. In embodiments, the water-soluble article with a single dose may comprise a water-soluble nonwoven web as described herein in the form of a bag defining an internal volume of the bag, and a composition to be dispensed enclosed in the internal volume of the bag, wherein the water-soluble nonwoven web may comprise a water-soluble mixture of PVOH and PVP. In embodiments, PVOH and PVP are present in a ratio of from about 95%:5% by weight to about 25%:75% by weight, respectively.

In addition, the present document provides a method for dispensing a composition into a large amount of water, comprising the step of contacting with the large amount of water a single-dose article of the present invention. In embodiments, the large amount of water dissolves at least a portion of the nonwoven web and releases the composition into the large amount of water. In embodiments, the nonwoven web of the single-dose article may comprise a plurality of fibers comprising a mixture of fiber-forming materials comprising (i) polyvinylpyrrolidone and (ii) polyvinyl alcohol (PVOH) modified with a sulfonate, PVOH modified with a carboxyl group, or both. In embodiments, the nonwoven web of the single dose article may comprise a plurality of fibers comprising a sulfonate-modified PVOH fiber-forming material comprising a sulfonated anionic monomer unit, wherein the sulfonate-modified PVOH fiber-forming material has a degree of hydrolysis of at least 95% and the sulfonated anionic monomer is present in an amount of from about 1 mol.% to about 5 mol.%. Typically, the large amount of water may be any large amount of water that requires a non-household care composition provided therein. In embodiments, the large amount of water may be a pool or a spa. Typically, the temperature of the large amount of water may be any temperature sufficient to dissolve or disintegrate at least a portion of the water-soluble nonwoven web. In embodiments, the large amount of water has a temperature of at least about 10°C, such as in the range of about 10°C to about 100°C, about 10°C to about 70°C, about 10°C to about 60°C, about 20°C to about 50°C, or about 20°C to about 40°C. Typically, the bulk water may have any pH. In embodiments, the pH of the large amount of water may be in the range of about 4 to about 10, about 5 to about 9, or about 6 to about 7.

Specific contemplated embodiments of the present disclosure are described in the following numbered paragraphs.

1. A water-soluble nonwoven fabric comprising: a plurality of fibers comprising (a) a mixture of fiber-forming materials comprising

(i) polyvinyl alcohol (PVOH) modified with a carboxyl group, and (ii) polyvinyl alcohol modified with a sulfonate, polyvinylpyrrolidone, or both; (b) a blend of fibers comprising (iii) a fiber comprising a fiberizing material of carboxyl-modified polyvinyl alcohol, and (iv) a fiber comprising a fiberizing material of sulfonate-modified polyvinyl alcohol, a fiber comprising a fiberizing material of polyvinylpyrrolidone, or both; or (c) a blend of fibres comprising (v) a first fibre comprising a fibre-forming material of carboxyl-modified polyvinyl alcohol, a fibre-forming material of sulfonate-modified polyvinyl alcohol, or a fibre-forming material of polyvinylpyrrolidone, and (vi) a second fibre comprising a blend of fibre-forming materials comprising a fibre-forming material of carboxyl-modified polyvinyl alcohol, a fibre-forming material of sulfonate-modified polyvinyl alcohol, a fibre-forming material of polyvinylpyrrolidone, or a combination thereof; wherein in any of (a), (b) and (c), the weight ratio of the carboxyl group-modified PVOH fiber-forming material to the sulfonate-modified PVOH fiber-forming materials and/or polyvinylpyrrolidone is from about 3:1 to about 19:1 by weight, respectively.

2. The water-soluble nonwoven fabric of claim 1, wherein the weight ratio of the fiber-forming material of carboxyl group-modified polyvinyl alcohol to the sulfonate and/or polyvinylpyrrolidone fiber-forming material is from about 5:1 to about 15:1 by weight, from about 5:1 to about 12:1 by weight, from about 5:1 to about 9:1 by weight, from about 6:1 to about 9:1 by weight, or from about 6.5:1 to about 7.5:1 by weight, respectively.

3. A water-soluble nonwoven fabric according to any one of the preceding claims, wherein the carboxyl group-modified PVOH comprises a maleate monomer unit selected from the group consisting of monomethyl maleate, maleic acid, maleic anhydride, alkali salts thereof, and combinations thereof.

4. The water-soluble nonwoven fabric of claim 3, wherein the maleate monomer unit is present in an amount in the range of from about 1 mol% to 10 mol%, or from about 1 mol% to 8 mol%, or from about 1 mol% to 5 mol%.

5. A water-soluble nonwoven fabric according to any one of the preceding claims, wherein the sulfonate-modified PVOH comprises a sulfonated anionic monomer unit selected from the group consisting of vinyl sulfonic acid, allyl sulfonic acid, ethylene sulfonic acid, 2-acrylamido-1-methylpropanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 2-methylacrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl acrylate, alkali salts thereof, or a combination thereof.

6. The water-soluble nonwoven fabric of claim 5, wherein the sulfonated anionic monomer is present in an amount in the range of from about 1 mol% to 10 mol%, or from about 1 mol% to 8 mol%, or from about 1 mol% to 5 mol%.

7. A water-soluble nonwoven fabric according to any one of the preceding claims, wherein the fiber-forming material (a) comprises polyvinylpyrrolidone, the fibers (b) comprise polyvinylpyrrolidone, or the second fiber (c) comprises a fiber-forming material of polyvinylpyrrolidone.

8. A water-soluble nonwoven fabric according to any one of the preceding claims, wherein the plurality of fibers further comprise cellulose modifiers, starch modifiers, or both.

9. A water-soluble nonwoven fabric according to any of the preceding claims, further comprising an acid absorbent.

10. The water-soluble nonwoven fabric of claim 9, wherein the acid absorbent is selected from the group consisting of N-vinylpyrrolidone, sodium metabisulfite, activated olefins, allyl compounds, ethylene-containing compounds, quaternary ammonium compounds, tertiary amine-containing compounds, and combinations thereof.

11. A water-soluble nonwoven fabric according to claim 9 or 10, wherein the acid absorbent is in or on the fiber, in or on the nonwoven fabric, or a combination thereof.

12. The water-soluble nonwoven fabric of claim 11, wherein the acid absorbent is applied to the fiber, to the nonwoven fabric, or to both.

13. The water-soluble nonwoven fabric of claim 11, wherein the acid absorbent is distributed throughout the nonwoven fabric.

14. A water-soluble nonwoven fabric according to any of the preceding paragraphs, additionally containing an antioxidant.

15. The water-soluble nonwoven fabric of claim 14, wherein the antioxidant is selected from the group consisting of propyl gallate, gallic acid, phenolic compounds, hindered amines, sodium metabisulfite, zinc acetate, and combinations thereof.

16. A water-soluble nonwoven fabric according to claim 14 or 15, wherein the antioxidant is within or on the fiber, within or on the nonwoven fabric, or a combination thereof.

17. The water-soluble nonwoven fabric of claim 16, wherein the antioxidant is applied to the fiber, to the nonwoven fabric, or to both.

18. The water-soluble nonwoven fabric of claim 16, wherein the antioxidant is distributed throughout the nonwoven fabric.

19. A water-soluble nonwoven fabric according to any of the preceding paragraphs, additionally containing a plasticizer.

20. The water-soluble nonwoven fabric of claim 19, wherein the plasticizer is selected from the group consisting of glycerin, diglycerin, sorbitol, ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tetraethylene glycol, propylene glycol, polyethylene glycol up to 400 MW, neopentyl glycol, trimethylolpropane, polyether polyols, 2-methyl-1,3-propanediol, ethanolamines, maltitol and combinations thereof.

21. The water-soluble nonwoven fabric of claim 20, wherein the plasticizer is selected from the group consisting of glycerol, maltitol, trimethylolpropane, and combinations thereof.

22. A water-soluble nonwoven fabric according to any of the preceding paragraphs, additionally containing a filler.

23. The water-soluble nonwoven fabric of claim 22, wherein the filler is selected from the group consisting of high amylose starch, amorphous silicon dioxide, hydroxyethyl starch, and combinations thereof.

24. A water-soluble nonwoven fabric according to any of the preceding paragraphs, additionally containing a surfactant.

25. The water-soluble nonwoven fabric of claim 24, wherein the surfactant comprises quaternary amines, myristyl dimethylamine oxide, alkyl polyethylene glycol ether, cocamides, or a combination thereof.

26. A water-soluble nonwoven fabric according to any one of items 1-25, wherein the nonwoven fabric has a disintegration time of no more than 300 seconds according to MSTM 205 in water at 23°C after exposure to trichloroisocyanuric acid (TCCA) or a sodium bisulfate composition (SBS) for 8 weeks at 38°C and 80% RH under ambient conditions.

27. The water-soluble nonwoven web of claim 26, wherein the surface area of the nonwoven web residue after testing according to MSTM 205 at 23°C is less than about 50% of the surface area of the nonwoven web before testing according to MSTM 205.

28. The water-soluble nonwoven fabric of any one of items 1-27, wherein the nonwoven fabric retains a b* value of no more than 3.5, or no more than 3.0, or no more than 2.5 after exposure to a TCCA or SBS composition for 8 weeks at 38°C and 80% RH under ambient conditions.

29. The water-soluble nonwoven web of any one of items 1-28, wherein the nonwoven web retains an average elongation of at least 90%, or at least 100%, or at least 120%, or at least 150%, or at least 175%, or at least 200% after exposure to a TCCA or SBS composition for 8 weeks at a temperature of 38°C and a relative humidity of 80%, in an atmosphere.

30. A single dose water-soluble product comprising a package comprising an outer wall, wherein the outer wall has an outer surface and the inner surface defines an internal volume of the package, wherein the outer wall comprises a water-soluble nonwoven fabric according to any one of the preceding claims; and a composition contained in the internal volume of the package.

31. A single-dose water-soluble product according to claim 30, wherein the composition contains an aggressive chemical substance.

32. A single-dose water-soluble article according to claim 31, wherein the aggressive chemical comprises an acid, an oxidizing agent, a base, or a combination thereof.

33. A single-dose water-soluble product according to claim 32, wherein the aggressive chemical is a chlorine-releasing compound.

34. The water-soluble single dose article of claim 32, wherein the acid comprises sodium bisulfate, cyanuric acid, dichloroisocyanuric acid, trichloroisocyanuric acid, citric acid, hydrochloric acid, or a combination thereof.

35. A single dose water soluble article according to item 32 or 33, wherein the oxidizing agent comprises hypochlorous acid, hypochlorite, halogenated isocyanurate, chlorite, chlorate, perchlorate, bromate, perbromate, halogenated hydantoin, perborate, periodate, persulfate, permanganate, chromate, dichromate, nitrate, nitrite, peroxide, ketone peroxide, peroxy acid, inorganic acid, or a combination thereof.

36. A single dose water soluble article according to claim 32, wherein the base comprises sodium carbonate, sodium bicarbonate, or a combination thereof.

37. A single dose water soluble product according to any of paragraphs 31-36, wherein the composition is not a home care composition.

38. A single dose water-soluble product according to claim 37, wherein the non-household care composition is selected from the group consisting of an agricultural composition, an aviation composition, a food and nutritional composition, an industrial composition, a livestock composition, a marine composition, a medical composition, a commercial composition, a military and/or quasi-military composition, an office composition, a recreational and/or park composition, a composition for pets, a composition for treating a layer of liquid (pool) and/or water, and a combination thereof.

39. A single-dose water-soluble product according to claim 38, wherein the composition for the care of non-household products is a composition for treating a layer of liquid (pool) and/or water.

40. A single dose water-soluble article according to claim 38 or 39, wherein the concentration of the acid, oxidizer, base or combination thereof in the non-household care composition is in the range of from 50% by weight to 100% by weight, or from 60% by weight to 100% by weight, or from 70% by weight to 100% by weight, or from 80% by weight to 100% by weight, or from 90% by weight to 100% by weight, based on the total weight of the non-household care composition.

41. A water-soluble single dose product according to any one of paragraphs 30-40, wherein the packaging further comprises a first coating comprising an acid scavenger, an antioxidant, or both, wherein the first coating is in contact with the outer wall.

42. A single dose water-soluble article according to claim 41, wherein a first coating comprising an acid scavenger, an antioxidant, or a combination thereof is applied to at least a portion of the inner surface of the outer wall.

43. A water-soluble single dose product according to claim 41 or 42, wherein the packaging further comprises a second coating comprising an acid scavenger, an antioxidant, or both.

44. A water-soluble single dose product according to claim 43, wherein the first coating is applied to at least a portion of the inner surface of the outer wall and the second coating is applied to at least a portion of the outer surface of the pouch.

45. A water-soluble single dose product according to any one of paragraphs 41-44, wherein the acid scavenger comprises N-vinylpyrrolidone, sodium metabisulfite, zinc oxide, hydrotalcite, metal stearate, activated olefins, allyl compounds, carboxylate compounds, ethylene-containing compounds, quaternary ammonium compounds, tertiary amine-containing compounds, or a combination thereof.

46. A water-soluble single dose article according to any one of paragraphs 41-45, wherein the antioxidant comprises propyl gallate, gallic acid, phenolic compounds, hindered amines, sodium metabisulfite, zinc acetate, or a combination thereof.

47. A single-dose water-soluble product containing

a water-soluble nonwoven fabric according to any one of items 1-29 in the form of a bag having an outer wall having an outer surface and an inner surface defining an inner volume of the bag, and a composition for treating a liquid and/or water layer contained in the volume of the inner bag, the concentration of an aggressive chemical substance in the composition for treating a liquid and/or water layer being in the range of 50% to 100% by weight,

and wherein the pouch optionally comprises a first coating comprising an acid absorbent applied to at least a portion of the inner surface of the outer wall.

48. A method for dosing a composition into a large quantity of water, comprising the steps of:

bringing into contact with a large quantity of water a water-soluble single dose product in accordance with any of paragraphs 30-47.

Elongation test

Specific strength can be analyzed in accordance with ASTM D 882. Briefly, an INSTRON® Tensile Tester (Model 5544 Tensile Tester or equivalent) is used to collect film data. A minimum of three test specimens, each cut with reliable cutting tools to ensure dimensional stability and repeatability, are tested in the direction of travel (MD) (where applicable) for each measurement. Testing is conducted in a standard laboratory atmosphere of 23 ± 2.0°C and 35 ± 5% relative humidity. Single sheet film specimens are prepared that are 1 in. (2.54 cm) wide and 3.0 ± 0.15 mils (or 76.2 ± 3.8 µm) thick. The specimen is then transferred to the INSTRON® Tensile Testing Machine for testing. The tensile testing machine is set up according to the manufacturer's instructions, equipped with a 500 N load cell and calibrated. The correct grips and surfaces (INSTRON® grips with model 2702-032 rubber-coated face, 25 mm wide, or equivalent) are installed. The specimens are placed in the tensile testing machine, pulled at a rate of 508 mm/min until the tensile stress has dropped by 10%. The elongation at which the tensile stress has dropped by 10% is the elongation at break.

Acceptable behavior of the films according to the invention is characterized by elongation values of at least about 90%, measured on an INSTRON® testing machine. In various embodiments, the film has an elongation value of at least 90%, at least 100%, at least 120%, at least 150%, at least 175%, or at least 200% after exposure to a TCCA or SBS composition for 8 weeks at a temperature of 38°C and a relative humidity of 80% in an atmosphere.

Dissolution, Disintegration and % Residue Test (MSTM 205)

The nonwoven web may be characterized or tested for dissolution time and disintegration time in accordance with the MonoSol 205 (MSTM 205) test method known in the art. See, for example, U.S. Patent No. 7,022,656.

Equipment and materials:

600 ml glass

Magnetic stirrer (Labline Model #1250 or equivalent)

Magnetic stirrer (5 cm)

Thermometer (0 to 100°C ± 1°C)

Template, stainless steel (3.8 cm x 3.2 cm)

Timer (0–300 seconds, accurate to the second)

Polaroid 35mm Slide Mount (or equivalent)

MonoSol 35mm Slide Holder (or similar)

Distilled water

For each nonwoven fabric to be tested, three test specimens are cut from a nonwoven fabric sample measuring 3.8 cm x 3.2 cm. When cutting from a nonwoven fabric, the specimens should be cut from sections of the fabric that are evenly spaced along the transverse direction of the fabric. Each test specimen is then analyzed using the following procedure.

Fix each specimen in a separate 35mm holder.

Fill a beaker with 500 ml of distilled water. Measure the temperature of the water with a thermometer and, if necessary, heat or cool the water to maintain the temperature at 20 °C (about 68 °F).

Mark the height of the water column. Place the magnetic stirrer on the base of the holder. Place the beaker on the magnetic stirrer, add the magnetic stirrer to the beaker, turn on the stirrer and adjust the stirring speed until a vortex forms that is approximately one-fifth the height of the water column. Mark the depth of the vortex.

Attach the 35 mm slide mount to the alligator clip of the 35 mm slide holder so that the long end of the slide mount is parallel to the surface of the water. The depth adjustment of the holder should be set so that when dropped, the end of the clip is 0.6 cm below the surface of the water. One of the short sides of the slide holder should be positioned next to the side of the beaker and the other should be positioned directly above the center of the stirrer so that the surface of the nonwoven fabric is perpendicular to the flow of water.

In one motion, lower the attached slide and clamp into the water and start the timer. Dissolution occurs when the nonwoven fabric breaks. When all visible nonwoven fabric has come out of the slide holder, lift the slide out of the water while continuing to monitor the solution for undissolved nonwoven fragments. Dissolution occurs when all nonwoven fragments are no longer visible and the solution becomes clear.

After 300 seconds, if any nonwoven fabric residue remained in the frame, the percentage of surface area of the remaining nonwoven fabric was assessed by visual inspection.

Results should include the following: complete sample identification; individual and average disintegration and dissolution times; and the water temperature at which the samples were tested.

The nonwoven fabric disintegration time (I) and the nonwoven fabric dissolution time (I) can be adjusted to a standard or reference thickness of the nonwoven fabric using the exponential algorithms shown below in Equation 1 and Equation 2, respectively.

I _corrected = I _measured x (reference thickness/measured thickness) ^1.93 [1]

S _corrected = S _measured x (reference thickness/measured thickness) ^1.83 [2]

CIELab test

The CIELab test is used to determine the reference yellowness of a sample using a Ci7600 spectrophotometer or equivalent.

Required equipment and materials

X-Rite Ci7600 Benchtop Spectrophotometer

X-Rite Color Master Software

Black Trap, for reflectance calibration

Aperture plate with white ring

Sample holder

Transmission plate to cover the reflective aperture plate when performing transmission measurements

White calibration tile covering the reflective aperture plate when calibration is complete.

Scissors for cutting out film samples.

Calibration of the Ci7600 spectrophotometer

Please note that aperture plates with a white ring inside MUST be used for transmission measurements. Open the Color Master software on your desktop. In the Color Master software, click the Tool tab. Click Calibration. Place the white calibration tile on the aperture plate. The UV setting should be set to EXC400. Close the transmission cover by lifting the locking pin and sliding the cover forward. Note: You should hear the pin click into place. Click OK in the software calibration window. Remove the tile from the aperture plate. Remove the black trap from the accessory drawer and place it on the aperture. Make sure the transmission cover is still closed and click OK in the software calibration window. Remove the black trap from the aperture plate. Place the transmission tile on the aperture plate. Once the calibration process has been successfully completed, the calibration indicator should turn green.

Creating a standard (for transmission measurements)

Make sure you are using the diaphragm with the white ring. Place the sample clip inside the instrument. Place the transmission plate on the aperture plate. Select the Instrument tab. Click Create Standard. Select Take a measurement with the attached instrument and click Next. Select whether you want to average the measurements and the number of measurements to take. Example: Three measurements are taken for the average. Place the 2X2 sample in the transmission sample clip. Close the transmission cover by lifting the locking pin and sliding the cover forward. Click Measure and repeat for each sample. Click Next. Enter a name for the standard. Optionally, enter a description for the standard. Click Next. If you want to change the tolerance or illuminant/observer characteristics, click Edit and make the desired changes. Otherwise, select Next. Select No when prompted to enter shade sort data and click Next. Select Done.

Selecting a standard (for transmission measurements)

Select the Database tab. Click Find Standard. Click the desired standard. The standard should be highlighted in blue. Then click Select. The standard is ready to use. To double check that the correct standard has been selected, check the box in the upper left corner of the program. This box should indicate the appropriate standard selected.

Measurement of samples (for transfer)

Mount the appropriate aperture plate (with white reflective ring) onto the measurement port on the front of the instrument. Place the white cap on the aperture plate. Attach the sample clamp and secure it to the base using the thumb screws. Select the Instrument tab. Click Measure Sample. A pop-up window will appear at the bottom left of the screen with the name of the standard being used. Move this window up so that it is visible on the screen. Change the specifications as needed, such as displaying SPIN (including specular reflectance) or SPEX (excluding specular reflectance) measurements and the illuminant/observer specification. Change the configuration to match the image below by clicking the hyperlink under Haze. Next to Lot I.D., enter a sample name for the sample being measured. Center the 2" X 2" sample in the transmission sample holder and place it between the stop and the clamp towards the sphere. Always make sure that the sample is level and parallel to the hole in the sphere. Close the lid. Press F8 on your keyboard or click on the right corner of Measure to take a measurement. You should hear a click and see a flash when the measurement is taken. Once the measurement is complete, remove the sample from the sample holder. If there is another sample, place it on the sample holder. Continue until all samples have been measured. Wait approximately 1 minute between sample measurements. Once the measurements are complete, exit the Trial Measurement window.

Test Results Report

The numerical data provided is for the CIE L*a*b* color measurement system. These values represent different aspects of the color of an object. The L value quantifies how light or dark the color is, with black and white being the two extremes. The a value quantifies how red or green the color is, with a positive value being more red and a negative value being more green. The b value quantifies how yellow or blue the color is, with a positive b value being more yellow and a negative b value being more blue. Record the Spex numerical data obtained for the L*a*b* color measurements under the F12/10 illuminant.

EXAMPLES

Example 1 – Exposure of PVOH nonwovens to aggressive chemicals

Water-soluble nonwoven webs containing sulfonate-modified PVOH or PVOH homopolymer fibers were formed into pouches containing trichloroisocyanuric acid (“TCCA”) and/or calcium hypochlorite (“Cal Hypo”). The pouches were stored in secondary packaging made of 4 mil HDPE film for 6 weeks at 38°C and 80% relative humidity. Dissolution, disintegration and/or % residue were measured according to MSTM 205, yellowness was measured according to the CIELab test and percent elongation was measured according to the elongation test. The results are presented in Table 1 below.

Dissolution/Disintegration: Specimens were measured at 0 weeks, 2 weeks, 4 weeks, and 6 weeks, except when the nonwovens did not dissolve or disintegrate at 0, 2, or 4 weeks, at which point testing was discontinued. A shorter dissolution or disintegration time indicated that the nonwoven was more resistant to the aggressive chemical, while a longer dissolution or disintegration time at 6 weeks indicated that the nonwoven was less resistant to the aggressive chemical.

Table 1

Fiber-forming material Chemical substance Impact (weeks) Size (um) Decay (c) Dissolution (s) Specific strength
Strength (N/ ^mm2 ) Elongation (%) Color
b* decay has/has not occurred 2 mol.% AMPS,
99+% DH PVOH absent 0 177 21 35 4.5 25.02 1.91 R 2 mol.% AMPS,
99+% DH PVOH absent 0 174 18 37 4.57 4.54 1.91 R 2 mol.% AMPS,
99+% DH PVOH absent 0 177 18 35 4.28 6.26 1.9 R 2 mol.% AMPS,
99+% DH PVOH TCSA 2 278 >300 >300 2.19 94.93 6.3 F 2 mol.% AMPS,
99+% DH PVOH TCCA 2 264 >300 >300 0.48 72.17 6.77 F 2 mol.% AMPS,
99+% DH PVOH TCCA 2 258 >300 >300 0.34 71.84 6.85 F 2 mol.% AMPS,
99+% DH PVOH Cal Hypo 2 149.86 55 >300 3.3 12.34 2.62 P 2 mol.% AMPS,
99+% DH PVOH Cal Hypo 2 149.86 56 >300 3.16 20.89 2.51 P 2 mol.% AMPS,
99+% DH PVOH Cal Hypo 2 149.86 55 >300 1.88 10.15 2.51 P 2 mol.% AMPS,
99+% DH PVOH Cal Hypo 4 149.86 41 >300 4.31 7.6 2.88 P 2 mol.% AMPS,
99+% DH PVOH Cal Hypo 4 149.86 82 >300 3.07 17.96 2.73 P 2 mol.% AMPS,
99+% DH PVOH Cal Hypo 4 149.86 68 >300 2.43 34,36 2.7 P 2 mol.% AMPS,
99+% DH PVOH Cal Hypo 6 182.88 86 >300 3.71 7 2.78 P 2 mol.% AMPS,
99+% DH PVOH Cal Hypo 6 182.88 64 >300 3.06 10.28 2.69 P 2 mol.% AMPS,
99+% DH PVOH Cal Hypo 6 172.72 101 >300 6.53 7.81 2.78 P PVOH
Homopolymer 23 cP,
88% DH absent 0 90.17 20 53 1.86 R PVOH
Homopolymer 23 cP,
88% DH absent 0 92.17 18 58 R PVOH
Homopolymer 23 cP,
88% DH absent 0 86.36 18 57 R PVOH
Homopolymer 23 cP,
88% DH TCSA 2 172.72 >300 >300 5.67 16.65 17.66 F PVOH
Homopolymer 23 cP,
88% DH TCCA 2 157.48 >300 >300 4.79 16.55 16.63 F PVOH
Homopolymer 23 cP,
88% DH TCCA 2 175.26 >300 >300 5.45 19.02 18.36 F

Water-soluble nonwoven webs were prepared using fibers containing either 2 mol% AMPS-modified PVOH having a degree of hydrolysis of 99+% or PVOH homopolymers having a viscosity of 23 cP and a degree of hydrolysis of about 88 as the sole fiber-forming component of the material to determine the effect of aggressive chemicals on various PVOH resins, as shown in Table 1. In general, AMPS-modified PVOH fibers and PVOH homopolymer fibers were found to be poorly soluble after exposure to acid-mediated oxidants (e.g., TCCA) for 2 weeks at 38°C and 80% relative humidity. However, it was surprisingly found that AMPS modified PVOH fibers exhibit acceptable disintegration (e.g., nonwoven web disintegrates in less than 300 seconds according to MSTM 205) and acceptable color change (e.g., nonwoven web has a b* color value of less than 3.5 and even less than 3.0 according to CIELab test) after 2 weeks, 4 weeks and even 6 weeks of exposure to a base mediated oxidizer (e.g., calcium hypochlorite).

The foregoing description is given for clarity of understanding only and is not to be construed as unduly limiting, since modifications within the scope of the invention may be apparent to those skilled in the art.

All patents, publications and references cited herein are hereby incorporated by reference in their entirety. In the event of a conflict between this disclosure and the incorporated patents, publications and references, this disclosure shall control.

Claims (54)

1. A single dose product comprising a package comprising an outer wall, wherein the outer wall has an outer surface and an inner surface that defines the internal volume of the package, wherein the outer wall comprises a nonwoven fabric comprising a plurality of fibers comprising: (a) a sulfonate group modified polyvinyl alcohol (PVOH) fiber-forming material containing a sulfonate anionic monomer unit; wherein the fiber-forming material made from sulfonate-modified PVOH has a degree of hydrolysis of at least 95%, and the sulfonate anionic monomer is present in an amount in the range of from about 1 mol.% to about 5 mol.%; or (b) a mixture of fibre-forming materials comprising a fibre-forming material modified with sulfonate groups from polyvinyl alcohol (PVOH) (a) in combination with (i) polyvinylpyrrolidone, and (ii) a carboxyl-modified polyvinyl alcohol (PVOH) containing a carboxylate anionic monomer unit; and a composition contained in the internal volume of the package that contains an aggressive chemical substance that contains an oxidizing agent, a base, or a combination of both. 2. A single dose product according to claim 1, characterized in that the sulfonate anionic monomer unit is one or more units selected from the group consisting of vinyl sulfonic acid, allyl sulfonic acid, ethylene sulfonic acid, 2-acrylamido-1-methylpropane sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid (AMPS), 2-methylacrylamido-2-methylpropane sulfonic acid, 2-sulfoethyl acrylate and their alkaline salts. 3. A single-dose product according to paragraph 2, characterized in that the monomer unit of the sulfonate anionic monomer is AMPS. 4. A single dose article according to any one of paragraphs. 1-3, characterized in that the sulfonate anionic monomer is present in an amount in the range from about 1 mol.% to about 3 mol.%. 5. A single dose product according to claim 1, characterized in that the plurality of fibers additionally contain fiber containing cellulose, starch modified with carboxyl groups of PVOH, containing a carboxylate anionic monomer unit, or a combination thereof. 6. A single-dose product according to paragraph 1, characterized in that the nonwoven fabric additionally contains an acid absorber. 7. A single dose product according to claim 6, characterized in that the acid absorber is one or more compounds selected from the group consisting of N-vinylpyrrolidone, sodium metabisulfite, activated olefin, allyl compound, ethylene-containing compound, quaternary ammonium compound, and compounds containing a tertiary amine. 8. A single dose article according to claim 6 or 7, wherein the acid absorber is located in or on at least one of a plurality of fibers, in or on a nonwoven fabric, or in a combination of the above. 9. A single-dose product according to paragraph 8, characterized in that the acid absorber is applied to the fiber, to the non-woven fabric, or to both. 10. A single-dose product according to paragraph 8, characterized in that the acid absorber is dispersed throughout the nonwoven fabric. 11. A single-dose product according to paragraph 1, characterized in that the nonwoven fabric additionally contains an antioxidant. 12. A single dose product according to claim 11, wherein the antioxidant is one or more antioxidants selected from the group consisting of propyl gallate, gallic acid, a phenolic compound, a hindered amine, sodium metabisulfite, and zinc acetate. 13. A single dose article according to claim 11 or 12, wherein the antioxidant is in or on at least one of a plurality of fibers, in or on a nonwoven fabric, or in a combination of the above. 14. A single-dose product according to paragraph 13, characterized in that the antioxidant is applied to the fiber, to the non-woven fabric, or to both. 15. A single-dose product according to item 11, characterized in that the antioxidant is distributed throughout the entire nonwoven fabric. 16. A single-dose product according to paragraph 1, characterized in that the nonwoven fabric additionally contains a plasticizer. 17. A single-dose product according to claim 16, characterized in that the plasticizer is one or more plasticizers selected from the group consisting of glycerin, diglycerin, sorbitol, ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tetraethylene glycol, propylene glycol, polyethylene glycol up to 400 MW, neopentyl glycol, trimethylolpropane, polyether polyols, 2-methyl-1,3-propanediol, ethanolamines and maltitol. 18. A single-dose product according to claim 17, characterized in that the plasticizer is one or more plasticizers selected from the group consisting of glycerin, maltitol and trimethylolpropane. 19. A single-dose product according to claim 1, wherein the nonwoven fabric additionally contains a filler. 20. A single dose product according to claim 19, characterized in that the filler is one or more fillers selected from the group consisting of high amylose starch, amorphous silicon dioxide, and hydroxyethylated starch. 21. A single-dose product according to paragraph 1, characterized in that the nonwoven fabric additionally contains a surfactant. 22. The single dose article of claim 21, wherein the surfactant comprises one or more of the group consisting of a quaternary amine, myristyl dimethylamine oxide, polyethylene glycol alkyl ether, and cocamide. 23. A single dose product according to claim 1, characterized in that the nonwoven fabric has a disintegration time of no more than 300 seconds in accordance with MSTM 205 in water at a temperature of 23°C after exposure to calcium hypochlorite for 6 weeks in water at a temperature of 38°C and 80% relative humidity under ambient conditions. 24. A single-dose product according to claim 1, characterized in that the nonwoven fabric retains a b* value of no more than 3.5 after exposure to calcium hypochlorite for 6 weeks under conditions of 38°C and a relative air humidity of 80% under ambient conditions. 25. A single dose product according to claim 1, wherein the oxidizer is a chlorine-releasing compound. 26. A single dose article according to claim 1 or 25, characterized in that the oxidizer contains one or more of hypochlorous acid, hypochlorite, halogenated isocyanurate, chlorite, chlorate, perchlorate, bromate, perbromate, halogenated hydantoin, perborate, periodate, persulfate, permanganate, chromate, dichromate, nitrate, nitrite, peroxide, ketone peroxide, peroxy acid, and inorganic acid. 27. A single-dose product according to paragraph 1, characterized in that the aggressive chemical substance contains a base-mediated oxidizer. 28. A single-dose product according to paragraph 27, characterized in that the base-mediated oxidizer contains hypochlorite. 29. A single dose product according to claim 27, characterized in that the base contains one or more of sodium carbonate and sodium bicarbonate. 30. A single-dose product according to any of paragraphs 1, 25-29, characterized in that the composition is a composition for non-household care. 31. A single-dose product according to claim 30, characterized in that the composition for non-household care is one or more compositions selected from the group: an agricultural composition, an aviation composition, a food and nutritional composition, an industrial composition, a composition for livestock, a marine composition, a medical composition, a commercial composition, a military and/or quasi-military composition, an office composition, a recreational and/or park composition, a composition for domestic animals, and a composition for treating a layer of liquid in a pool and/or purifying water. 32. A single-dose product according to paragraph 31, characterized in that the composition for non-household care is a composition for treating a layer of pool liquid and/or water. 33. A single-dose product according to paragraph 31 or 32, characterized in that the concentration of the oxidizer, base, or combination thereof in the non-household care composition is in the range from 50 wt.% to 100 wt.% based on the total weight of the non-household care composition. 34. A single dose product according to any one of paragraphs 25-33, characterized in that the bag further comprises a first coating comprising an acid absorbent, an antioxidant, or both, wherein the first coating is in contact with the outer wall. 35. A single dose product according to item 34, characterized in that the first coating is applied to at least part of the inner surface of the outer wall. 36. A single dose product according to claim 34 or 35, characterized in that the package additionally contains a second coating containing an acid absorber, an antioxidant, or both. 37. A single dose product according to claim 36, characterized in that the first coating is applied to at least part of the inner surface of the outer wall, and the second coating is applied to at least part of the outer surface of the outer wall. 38. A single dose article according to any one of paragraphs 34-37, characterized in that the acid absorber comprises one or more of N-vinylpyrrolidone, sodium metabisulfite, zinc oxide, hydrotalcite, metal stearate, activated olefin, allyl compound, carboxylate compound, ethylene-containing compound, quaternary ammonium compound, and tertiary amine-containing compound. 39. A single dose article according to any one of paragraphs 34-38, characterized in that the antioxidant comprises one or more of propyl gallate, gallic acid, a phenolic compound, a hindered amine, sodium metabisulfite, and zinc acetate. 40. A single dose article according to claim 2, characterized in that the weight ratio of the polyvinylpyrrolidone fiber-forming material to the carboxyl group-modified fiber-forming material made of polyvinyl alcohol, the sulfonate group-modified fiber-forming material made of polyvinyl alcohol, or both is from about 1:1 to about 1:19 by weight. 41. A single dose article according to any one of paragraphs 2-40, characterized in that the PVOH modified with carboxyl groups contains one or more monomer units of maleate selected from the group consisting of monomethyl maleate, maleic acid, maleic anhydride and their alkali salt. 42. A single dose product according to claim 41, characterized in that the maleate monomer unit is present in an amount in the range from about 1 mol.% to 10 mol.%. 43. A single-dose product according to any one of paragraphs 1-42, characterized in that the composition contained in the internal volume of the package is intended for treating a layer of liquid and/or water and contains an oxidizer, the concentration of the oxidizer in the composition for treating a layer of liquid and/or water is in the range from 50% to 100% by weight; wherein the oxidizing agent comprises calcium hypochlorite, and the pouch optionally comprises a first coating comprising an acid absorber applied to at least a portion of the inner surface of the outer wall. 44. A single-dose product according to any one of paragraphs 1-42, characterized in that the composition contained in the internal volume of the package is intended for treating a layer of liquid and/or water, and contains an oxidizer, the concentration of the oxidizer in the composition for treating a layer of liquid and/or water is in the range from 50 wt.% to 100 wt.%; and wherein the oxidizing agent comprises trichloroisocyanuric acid, and the pouch optionally comprises a first coating comprising an acid absorber applied to at least a portion of the inner surface of the outer wall. 45. A method for dosing a composition into a volume of water, comprising the steps of: bringing into contact with a large amount of water a single-dose product according to any of paragraphs 1-44.