Recycled Sulfopolyester

Abstract

The present disclosure provides a method for recovering a sulfopolyester containing reduced impurities. The sulfopolyester is recovered from a composite material comprising a water-dispersible sulfopolyester polymer and at least one water-non-dispersible polymer. The method includes washing the composite material comprising the water-dispersible sulfopolyester with a solvent composition. The recovered sulfopolyester can be produced as a concentrated aqueous dispersion, a polymer melt, or a sulfopolyester solid.

Description

Technical Field

[0001] The present disclosure describes methods for recovering sulfopolyesters from composite materials. Background of the Invention

[0003] Recycling involves methods of converting materials that would otherwise be discarded into new products. Recycling benefits the environment by reducing waste sent to landfills, conserving natural resources, preventing pollution, and saving energy.

[0004] Many composite materials are made from water-dispersible polymers. An example of a water-dispersible polymer is sulfopolyester. Sulfopolyesters are used to form fibers and fiber products, including nonwovens, multicomponent fibers, films, apparel articles, personal care products such as wipes, feminine hygiene products, diapers, adult incontinence briefs, disposable medical supplies, protective fabrics and layers, geotextiles, industrial wipes, and filtration media.

[0005] In the past, processes have been developed for recycling or recovering sulfopolyesters from materials that were intended for disposal, since the recovered sulfopolyesters can be used to make new articles. Therefore, there is a continuing interest in developing improved processes for more efficiently and economically recovering sulfopolyesters having increased purity. SUMMARY OF THE INVENTION

[0007] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify all key features or essential features of the claimed subject matter, nor is it intended to be used alone as an aid in determining the scope of the claimed subject matter.

[0008] A method for recovering a sulfopolyester from a composite material is provided. The method comprises: washing the composite material with a solvent composition to remove a portion of surface impurities and form a washed composite material, wherein the washing is performed at a temperature where less than 2% of the water-dispersible sulfopolyester is removed from the composite material, and wherein the composite material comprises a water-dispersible sulfopolyester and one or more water-non-dispersible polymers; opening the washed composite material with water at a temperature greater than 60° C. to produce an aqueous dispersion and a water-non-dispersible polymer, wherein the aqueous dispersion comprises the sulfopolyester; and recovering the sulfopolyester from the aqueous dispersion.

[0009] In addition, a method for recovering sulfopolyester from fibers, such as multicomponent fibers comprising water-dispersible sulfopolyester, is provided. The method comprises cutting the fibers into chopped fibers; washing the chopped fibers comprising the water-dispersible sulfopolyester with a washing solvent composition at a temperature where less than 2% of the water-dispersible sulfopolyester is removed from the composite material, wherein the chopped fibers comprise the water-dispersible sulfopolyester and one or more water-non-dispersible polymers; opening the chopped fibers with water at a temperature above 60° C. to produce an aqueous dispersion and a water-non-dispersible polymer, wherein the aqueous dispersion comprises the sulfopolyester; and recovering the sulfopolyester from the aqueous dispersion.

[0010] In embodiments, the washed composite material and washed chopped fibers may be mixed with treated water prior to opening, wherein the water has been treated to remove multivalent metal cations.

[0011] The cleaning solvent composition comprises water. The cleaning solvent composition may also comprise one or more surfactants and / or one or more organic solvents. Examples of surfactants include anionic surfactants and / or nonionic surfactants. Examples of organic solvents include alcohols, acetone, ketones, ethers and / or esters. In embodiments, the cleaning solvent composition consists essentially of water.

[0012] Washing with the washing solvent composition is performed at a temperature of 20° C. to 60° C., 20° C. to 50° C., 20° C. to 40° C., and 20° C. to 30° C. Washing includes contacting the composite material or fiber with a shear force to remove at least a portion of the impurities. Washing is performed for 15 seconds to 15 minutes, 20 seconds to 12 minutes, 30 seconds to 10 minutes, 1 minute to 8 minutes, 1 minute to 5 minutes, or 1 minute to 3 minutes.

[0013] After washing, the washed composite or washed chopped fibers are opened with water at a temperature of 61° C. to 140° C., 65° C. to 135° C., 70° C. to 130° C., 75° C. to 125° C., 80° C. to 120° C., 80° C. to 115° C., 80° C. to 110° C., 80° C. to 105° C., 80° C. to 100° C., or 80° C. to 90° C. The opening is performed with shear force for a period of 10 seconds to 10 minutes, 20 seconds to 8 minutes, 20 seconds to 5 minutes, 20 seconds to 4 minutes, 20 seconds to 3 minutes, 20 seconds to 2 minutes, or 20 seconds to 1 minute.

[0014] Recovering the sulfopolyester includes removing water from the aqueous dispersion. The recovered sulfopolyester comprises a concentrated sulfopolyester dispersion, a solid form of the sulfopolyester containing some moisture, and a polymer melt.

[0015] The water may be removed by evaporation, by precipitation or by using one or more membrane filtration systems. Examples of one or more membrane filtration systems for removing water include one or more of an ultrafiltration system, a microfiltration system or a nanofiltration system.

[0016] Recovering the sulfopolyester using a membrane filtration technique provides a concentrated sulfopolyester dispersion. In embodiments, the concentrated sulfopolyester dispersion comprises 1 wt % to 40 wt %, 1 wt % to 35 wt %, 5 wt % to 30 wt %, 10 wt % to 30 wt %, 15 wt % to 30 wt %, 20 wt % to 30 wt %, or 25 wt % to 30 wt % sulfopolyester relative to the total weight of the concentrated sulfopolyester dispersion.

[0017] Water may also be removed by evaporation using an evaporator. In embodiments, the sulfopolyester recovered by evaporation is in the form of a solid containing less than 5% moisture content, less than 4% moisture content, less than 3% moisture content, less than 2% moisture content, less than 1% moisture content, or less than 0.5% moisture content by weight relative to the total weight of the solid. In other embodiments, the sulfopolyester recovered by evaporation may be produced in the form of a dispersion wherein the percentage of polymer ranges from 1% to 10%, 11% to 20%, 21% to 30%, 31% to 40%, 41% to 50%, 51% to 60%, 61% to 70%, or 71% to 80%. In still other embodiments, the sulfopolyester recovered by evaporation with additional heating may be in the form of a polymer melt which, when cooled, produces the sulfopolyester in solid form.

[0018] In embodiments, the method further comprises subjecting the aqueous dispersion comprising the sulfopolyester to a secondary filtration prior to recovering the sulfopolyester. The secondary filtration comprises passing the aqueous dispersion through a pleated cartridge filter and / or other filters.

[0019] In embodiments, the methods recover 75% to 99.9%, 75% to 99%, 80% to 98%, 85% to 97%, 90% to 96%, or 91% to 95% of the sulfopolyester in the composite or fiber.

[0020] Furthermore, each step of the method for recovering the sulfopolyester from the composite material, composite solids, or multicomponent fibers can be performed in a separate zone. In embodiments, washing is performed in a washing zone; mixing is performed in a mixing zone; opening is performed in an opening zone; and recovery of the sulfopolyester is performed in a recovery zone. In embodiments, the method further comprises a first solid-liquid separation (SLS) zone, a second (SLS) zone, a first concentrating zone, and a second concentrating zone for recovering the sulfopolyester.

[0021] The recovered sulfopolyester dispersion obtained by the process described herein comprises a recovered sulfopolyester and a solvent composition; wherein the dispersion comprises 0.01 wt % to 5 wt % impurities relative to the total weight of the recovered sulfopolyester dispersion. The recovered sulfopolyester may also comprise a washed (pre-washed) recovered sulfopolyester dispersion, the dispersion comprising a recovered sulfopolyester and a solvent composition; wherein the dispersion has an impurity concentration reduced by at least 80% or more compared to a recovered sulfopolyester dispersion that has not been pre-washed. In addition, the recovered sulfopolyester may comprise a washed (pre-washed) recovered sulfopolyester dispersion, the dispersion comprising an impurity level of 0.01% to 5%. Further, the recovered sulfopolyester may comprise a washed (pre-washed) recovered sulfopolyester dispersion, the dispersion substantially comprising a two-phase system.

[0022] The recycled sulfopolyester and recycled sulfopolyester dispersions can be used to make a variety of articles and products, including multicomponent fibers, fabrics, articles of apparel, cosmetics, and personal care products. In embodiments, the recycled sulfopolyester dispersions can be used to make sizing agents, dust suppressants, adhesives, and inks. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 An exemplary method for recovering sulfopolyester from a composite material is shown.

[0025] Figure 2 One embodiment of a method for recovering sulfopolyester from a composite material is shown.

[0026] Figure 3 One embodiment of a process for recovering sulfopolyester from chopped multicomponent fibers is shown.

[0027] Detailed Description

[0028] This disclosure describes a novel method for recovering sulfopolyesters from articles we use every day. For example, various articles are made from composite materials made using water-dispersible sulfopolyesters. The sulfopolyesters can be recovered from these articles and reused to make new and useful articles and products.

[0029] The inventors have surprisingly discovered that the step of washing (or pre-washing) the starting material containing the sulfopolyester in the recycling method removes additional undesirable impurities, which may have been added to the material through the manufacturing process. The terms "pre-washing" and "washing" are used interchangeably and mean washing the composite material, composite solids or multi-component fibers before opening and / or before mixing with treated water. The term "impurity" is defined as any liquid or solid on the surface of the unopened fiber that does not contain the sulfopolyester or base polymer in the fiber. Impurities include, but are not limited to, surface impurities, which include oils, slip agents, fillers, surface friction modifiers, light and heat stabilizers, extrusion aids, antistatic agents, colorants, dyes, pigments, fluorescent whitening agents, antimicrobial agents, anti-counterfeiting markings, antioxidants, hydrophobic and hydrophilic enhancers, viscosity modifiers, slip agents, tougheners or adhesion promoters.

[0030] Figure 1 An exemplary method of recovering a sulfopolyester from a composite material is provided, wherein the method comprises:

[0031] a. washing the composite with a solvent composition to remove a portion of the surface impurities to form a washed composite; wherein the washing is performed at a temperature where less than 2% of the water-dispersible sulfopolyester is removed from the composite, and wherein the composite comprises a water-dispersible sulfopolyester and one or more water-non-dispersible polymers;

[0032] b. opening the washed composite material with water at a temperature above 60° C. to produce an aqueous dispersion and a water-non-dispersible polymer, wherein the aqueous dispersion comprises a sulfopolyester; and

[0033] c. Recovery of the sulfopolyester from the aqueous dispersion.

[0034] In embodiments, a method for recovering a sulfopolyester comprises washing a material comprised of a sulfopolyester with a washing solvent composition at a temperature below 60°C, opening the washed composite at a temperature above 60°C, and recovering the sulfopolyester from the aqueous dispersion in the form of an aqueous dispersion, a concentrated aqueous dispersion, a solid, or a polymer melt.

[0035] The starting materials used in the methods described herein include composite materials (composite materials, composite) composed of sulfopolyesters (and sulfopolyesters recovered therefrom). The term "composite material" refers to a material made from two or more component materials having different physical and chemical properties. The individual components remain independent and different in the final material. In an embodiment, the components of the composite material described herein include a water-dispersible sulfopolyester and one or more water-indispersible polymers. The terms "composite material", "composite solids" and "plurality of composite solids" are used interchangeably to refer to a composite material or composite materials.

[0036] The term "water dispersible" with respect to the sulfopolyester is intended to be synonymous with the terms "water-diffusible," "water-decomposable," "water-soluble," "water-digestible," "water-soluble," "water-mobile," "water-soluble," and "water-dispersible." It is also intended to mean that the sulfopolyester component is removed from a composite material, such as a multicomponent fiber, and dispersed or dissolved by the action of water. In the case of a multicomponent material, the sulfopolyester is removed so as to enable the release and separation of the water-non-dispersible fibers contained therein. The terms "dispersed," "dispersible," "diffusible," or "diffusible" mean that using a sufficient amount of deionized water (e.g., 100:1 water:fiber by weight) to form a loose suspension or slurry of the water-non-dispersible polymer, the dissolved sulfopolyester component decomposes, breaks apart or separates from the water-non-dispersible polymer in the composite material, leaving a plurality of solids, at a temperature above 60°C and over a period of time of up to 5 days.

[0037] The water-dispersible sulfopolyester contained in the composite material, composite solid or multicomponent fiber contains dicarboxylic acid monomer residues, sulfomonomer residues, and diol monomer residues as repeating units. The sulfomonomer can be a dicarboxylic acid, a diol or a hydroxycarboxylic acid. Therefore, as used herein, the term "monomer residue" refers to the residue of a dicarboxylic acid, a diol or a hydroxycarboxylic acid. As used herein, "repeat unit" refers to an organic structure having 2 monomer residues bonded by a carbonyloxy group. The water-dispersible sulfopolyester contains substantially equal molar proportions of acid residues (100 mole %) and diol residues (100 mole %), which react in substantially equal proportions so that the total moles of repeating units are equal to 100 mole %. The sulfopolyester will contain 100 mole % of the total diacid residues and 100 mole % of the total diol residues. Therefore, the mole percentages provided herein can be based on the total moles of diacid residues, the total moles of diol residues, or the total moles of repeating units. For example, a sulfopolyester containing 30 mole % sulfomonomer (which may be a dicarboxylic acid, diol, or hydroxycarboxylic acid) based on total repeating units means that the sulfopolyester contains 30 mole % sulfomonomer out of a total of 100 mole % repeating units. Thus, there are 30 moles of sulfomonomer residues per 100 moles of repeating units. Similarly, a sulfopolyester containing 30 mole % dicarboxylic acid sulfomonomer based on total acid residues means that the sulfopolyester contains 30 mole % sulfomonomer out of a total of 100 mole % acid residues. Thus, in this latter case, there are 30 moles of sulfomonomer residues per 100 moles of acid residues.

[0038] The sulfopolyesters described herein have an intrinsic viscosity of at least 0.1 dL / g, 0.2-0.3 dL / g, or 0.3 dL / g, hereinafter abbreviated as "Ih.V.", measured in a solution of 60 / 40 parts by weight phenol / tetrachloroethane solvent at 25°C and at a concentration of 0.5 g of sulfopolyester in 100 mL of solvent. As used herein, the term "polyester" includes both "homopolyesters" and "copolyesters" and includes synthetic polymers prepared by the polycondensation of a difunctional carboxylic acid with a difunctional hydroxy compound. As used herein, the term "sulfopolyester" refers to any polyester containing a sulfonic monomer.

[0039] Typically, the difunctional carboxylic acid is a dicarboxylic acid and the difunctional hydroxy compound is a dihydric alcohol, such as, for example, glycol and diol. Alternatively, the sulfopolyester may contain a hydroxy acid monomer, such as p-hydroxybenzoic acid, and the difunctional hydroxy compound may be an aromatic nucleus with 2 hydroxy substituents, such as, for example, hydroquinone. Aromatic hydroxy acids and aromatic diols are within the scope, although less preferred. As used herein, the term "residue" refers to any organic structure incorporated into a polymer by a polycondensation reaction involving the corresponding monomer. Thus, a dicarboxylic acid residue may be derived from a dicarboxylic acid monomer or its associated acid halide, ester, anhydride, or mixture thereof. Thus, as used herein, the term dicarboxylic acid is intended to include dicarboxylic acids and any derivatives of dicarboxylic acids, including their associated acid halides, esters, half-esters, salts, half-salts, anhydrides, mixed anhydrides, or mixtures thereof, which may be used in a polycondensation process with a diol to prepare a high molecular weight polyester.

[0040] The water dispersible sulfopolyester includes one or more dicarboxylic acid residues. Depending on the type and concentration of the sulfomonomer, the dicarboxylic acid residues may contain 60-100 mole % of the acid residues. Other examples of concentration ranges for the dicarboxylic acid residues are 60 mole % to 95 mole %, and 70 mole % to 95 mole %. Examples of dicarboxylic acids that may be used include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, aromatic dicarboxylic acids, or mixtures of two or more of these acids. Thus, suitable dicarboxylic acids include, but are not limited to, succinic acid; glutaric acid; adipic acid; azelaic acid; sebacic acid; fumaric acid; maleic acid; itaconic acid; 1,3-cyclohexanedicarboxylic acid; 1,4-cyclohexanedicarboxylic acid; diethylene glycol acid; 2,5-norbornanedicarboxylic acid; phthalic acid; terephthalic acid; 1,4-naphthalenedicarboxylic acid; 2,6-naphthalenedicarboxylic acid; biphenyldicarboxylic acid; 4,4'-diphenyletherdicarboxylic acid; 4,4'-sulfonyidibenzoic; and isophthalic acid. In embodiments, the dicarboxylic acid residues are isophthalic acid, terephthalic acid, and 1,4-cyclohexanedicarboxylic acid, or (if a diester is used) dimethyl terephthalate, dimethyl isophthalate, and dimethyl 1,4-cyclohexanedicarboxylate. In specific embodiments, the dicarboxylic acid residues are isophthalic acid and terephthalic acid. Although methyl dicarboxylates are most commonly used, it is also acceptable to include higher alkyl esters such as ethyl, propyl, isopropyl, butyl, etc. In addition, aromatic esters may also be used, particularly phenyl esters.

[0041] The water dispersible sulfopolyester comprises 4-40 mol% of residues of at least one sulfomonomer having two functional groups and one or more sulfonate groups attached to an aromatic or alicyclic ring, wherein the functional groups are hydroxyl, carboxyl, or a combination thereof, based on the total repeating units. Other examples of concentration ranges for the sulfomonomer residues are 4-35 mol%, 8-30 mol%, and 8-25 mol%, based on the total repeating units. The sulfomonomer can be a dicarboxylic acid or ester thereof containing a sulfonate group, a diol containing a sulfonate group, or a hydroxy acid containing a sulfonate group. The term "sulfonate" refers to a salt of a sulfonic acid having the structure "-SO3M", wherein M is a cation of the sulfonate. The cation of the sulfonate can be a metal ion, such as Li + 、Na + , K + Mg ++ , Ca ++ 、Ni ++ , Fe ++ etc. Multivalent cations, such as Mg ++ , Ca ++ 、Ni ++ , Fe ++ Small amounts are permitted, but are not preferred in the practice of the present invention. Alternatively, the cation of the sulfonate may be non-metallic, such as a nitrogenous base. Nitrogen-based cations are derived from nitrogenous bases, which may be aliphatic, alicyclic or aromatic compounds. Examples of such nitrogenous bases include ammonia, dimethylethanolamine, diethanolamine, triethanolamine, pyridine, morpholine and piperidine. Since monomers containing nitrogen-based sulfonates are generally not thermally stable under the conditions required for preparing melt polymers, a method for preparing sulfopolyesters containing nitrogen-based sulfonate groups is to disperse, diffuse, or dissolve a polymer containing the desired amount of sulfonate groups in water in the form of its alkali metal salt, and then exchange the alkali metal cations with nitrogen-based cations.

[0042] When a monovalent alkali metal ion is used as the cation of the sulfonate, the resulting sulfopolyester is completely dispersible in water, with the rate of dispersion depending on the amount of sulfomonomer in the polymer, the temperature of the water, the surface area / thickness of the sulfopolyester, etc. The use of more than one counterion within a single polymer composition is possible and may provide a means to adjust or fine tune the water responsiveness of the resulting article of manufacture. Examples of sulfomonomer residues include monomer residues in which the sulfonate group is attached to an aromatic acid nucleus, such as, for example, benzene; naphthalene; biphenyl; oxybiphenyl; sulfonylbiphenyl and methylenebiphenyl or an alicyclic ring, such as, for example, cyclohexyl; cyclopentyl; cyclobutyl; cycloheptyl and cyclooctyl. Other examples of sulfomonomer residues useful in the present invention are metal sulfonates of sulfophthalic acid, sulfoterephthalic acid, sulfoisophthalic acid, or combinations thereof. Other examples of sulfomonomers that may be used are sodium 5-sulfoisophthalate and its esters. If the sulfomonomer residues are derived from sodium 5-sulfoisophthalic acid, typical sulfomonomer concentration ranges are 4-35 mole %, 8-30 mole %, and 8-25 mole %, based on the total moles of acid residues.

[0043] The sulfomonomers used to prepare the sulfopolyesters are known compounds and can be prepared using methods well known in the art. For example, sulfomonomers in which the sulfonate group is attached to an aromatic ring can be prepared by sulfonating an aromatic compound with oleum to obtain the corresponding sulfonic acid, and then reacting it with a metal oxide or a base such as sodium acetate to prepare the sulfonate. Procedures for the preparation of various sulfomonomers are described, for example, in U.S. Pat. Nos. 3,779,993; 3,018,272 and 3,528,947, which are incorporated by reference in their entireties.

[0044] The water-dispersible sulfopolyester includes one or more diol residues, which may include aliphatic diols, cycloaliphatic diols, and aralkyl diols. Cycloaliphatic diols, such as 1,3- and 1,4-cyclohexanedimethanol, may exist as their pure cis or trans isomers or as a mixture of cis and trans isomers. As used herein, the term "diol" is synonymous with the term "glycol" and means any dihydric alcohol. Examples of diols include, but are not limited to, ethylene glycol; diethylene glycol; triethylene glycol; polyethylene glycol; 1,3-propylene glycol; 2,4-dimethyl-2-ethylhexane-1,3-diol; 2,2-dimethyl-1,3-propylene glycol; 2-ethyl-2-butyl-1,3-propylene glycol; 2-ethyl-2-isobutyl-1,3-propylene glycol; 1,3-butylene glycol; 1,4-butylene glycol; 1,5-pentanediol; 1,6-hexanediol; 2,2,4-trimethyl-1,6-hexanediol; thiodiethanol; 1,2-cyclohexanedimethanol; 1,3-cyclohexanedimethanol; 1,4-cyclohexanedimethanol; 2,2,4,4-tetramethyl-1,3-cyclobutanediol; p-xylylenediol, or a combination of one or more of these diols.

[0045] The diol residues may include from 25 mol % to 100 mol % of residues of poly(ethylene glycol) having the structure

[0046] H-(OCH2-CH2) n -OH

[0047] Wherein n is an integer in the range of 2 to 500. Non-limiting examples of relatively low molecular weight polyethylene glycols, such as where n is 2 to 6, are diethylene glycol, triethylene glycol, and tetraethylene glycol. Examples of relatively low molecular weight glycols include diethylene glycol and triethylene glycol. Higher molecular weight polyethylene glycols (abbreviated herein as "PEG"), where n is 7 to 500, include commercially available products known by the name CARBOWAX®, a product of Dow Chemical Company (formerly Union Carbide). Typically, PEG is used in combination with other glycols such as diethylene glycol or ethylene glycol. Based on n values ​​in the range of greater than 6 to 500, the molecular weight may be in the range of greater than 300-22,000 g / mol. Molecular weight and mole percent are inversely proportional to each other; specifically, as the molecular weight increases, the mole % will decrease in order to achieve a specified degree of hydrophilicity. For example, it is contemplated for purposes of illustrating the present concept that a PEG having a molecular weight of 1000 may constitute up to 10 mol % of the total glycol, whereas a PEG having a molecular weight of 10,000 will typically be incorporated at levels less than 1 mol % of the total glycol.

[0048] Since the side reaction can form some dimer, trimer and tetramer glycols in situ, the side reaction can be controlled by changing the process conditions. For example, by the acid-catalyzed dehydration reaction that easily occurs when the polycondensation reaction is carried out under acidic conditions, varying amounts of diethylene glycol, triethylene glycol and tetraethylene glycol can be formed from ethylene glycol. The presence of a buffer solution well known to those skilled in the art can be added to the reaction mixture to prevent these side reactions. However, additional composition ranges are possible if the buffer solution is omitted and dimerization, trimerization and tetramerization are allowed.

[0049] Based on the total repeating unit, the water-dispersible sulfopolyester may include 0-25 mol % of the residue of a branched monomer with 3 or more functional groups, wherein the functional group is a hydroxyl, a carboxyl or a combination thereof. Non-limiting examples of branched monomers are 1,1,1-trimethylolpropane, 1,1,1-trimethylolethane, glycerol, pentaerythritol, erythritol, threitol, dipentaerythritol, sorbitol, trimellitic anhydride, pyromellitic dianhydride, dimethylol propionic acid or a combination thereof. Further examples of branched monomer concentration ranges are 0-20 mol % and 0-10 mol %. The presence of branched monomers may result in many possible benefits to water-dispersible sulfopolyesters, including but not limited to the ability to customize rheology, solubility and tensile properties. For example, at a constant molecular weight, compared to linear analogs, branched sulfopolyesters will also have a greater end group concentration, which can promote crosslinking reactions after polymerization. However, at high branching agent concentrations, sulfopolyesters may be easily gelled.

[0050] The glass transition temperature (abbreviated herein as "Tg") of the water-dispersible sulfopolyesters is at least 25°C as measured on dry polymer using standard techniques such as differential scanning calorimetry ("DSC"), which are well known to those skilled in the art. Tg measurements of the sulfopolyesters of the present invention are made using "dry polymer," that is, a polymer sample in which adventitious or absorbed water has been screened off by heating the polymer to a temperature of 200°C and returning the sample to room temperature. Typically, the sulfopolyesters are dried in a DSC instrument by conducting a first thermal scan in which the sample is heated to a temperature greater than the water vaporization temperature, holding the sample at this temperature until absorbed water in the polymer is completely vaporized (as indicated by a large, significant endotherm), cooling the sample to room temperature, and then subjecting it to a second thermal scan to obtain a Tg measurement. Further examples of glass transition temperatures exhibited by the sulfopolyesters are at least 30° C., at least 35° C., at least 40° C., at least 50° C., at least 60° C., at least 65° C., at least 80° C., at least 90° C., and at least 100° C. In embodiments of the present invention, the glass transition temperature of the sulfopolyesters may be between 30° C. and 120° C., 35° C. and 100° C., 40° C. and 90° C., 45° C. and 80° C., and 50° C. and 70° C. Although other Tgs are possible, typical glass transition temperatures for the sulfopolyesters are 30° C., 48° C., 55° C., 65° C., 70° C., 75° C., 85° C., and 90° C.

[0051] The water-dispersible sulfopolyester used in the present invention may contain 1,4-cyclohexanedimethanol residues, wherein the sulfopolyester is selected from at least one of the following:

[0052] (1) A water-dispersible sulfopolyester comprising:

[0053] (a) residues of one or more dicarboxylic acids;

[0054] (b) at least 10 mole percent of residues of at least one sulfomonomer; and

[0055] (c) residues of two or more diols, wherein the diols include 1,4-cyclohexanedimethanol and diethylene glycol,

[0056] wherein the sulfopolyester exhibits a glass transition temperature of at least 57°C, wherein said sulfopolyester comprises substantially equal molar proportions of acid moiety repeating units (100 mole percent) and hydroxy moiety repeating units (100 mole percent), and wherein all said mole percents are based on the sum of all acid and hydroxy moiety repeating units, said sum being equal to 200 mole percent;

[0057] (2) A water-dispersible sulfopolyester comprising:

[0058] (a) residues of isophthalic acid;

[0059] (b) residues of terephthalic acid;

[0060] (c) the residue of at least one sulfomonomer;

[0061] (d) residues of 1,4-cyclohexanedimethanol; and

[0062] (e) residues of diethylene glycol,

[0063] wherein the sulfopolyester exhibits a glass transition temperature of at least 57°C, wherein said sulfopolyester contains substantially equal molar proportions of acid moiety repeating units (100 mole percent) to hydroxy moiety repeating units (100 mole percent), and wherein all said mole percents are based on the sum of all acid and hydroxy moiety repeating units, said sum being equal to 200 mole percent; and

[0064] (3) A water-dispersible sulfopolyester comprising:

[0065] (a) residues of one or more dicarboxylic acids;

[0066] (b) at least 10 mole percent of residues of at least one sulfomonomer; and

[0067] (c) residues of two or more diols, wherein the diols include 1,4-cyclohexanedimethanol and diethylene glycol,

[0068] The sulfopolyester exhibits a glass transition temperature of at least 57°C, wherein the sulfopolyester contains substantially equal molar proportions of acid portion repeating units (100 mole percent) and hydroxy portion repeating units (100 mole percent).

[0069] These water dispersible sulfopolyesters containing 1,4-cyclohexanedimethanol residues have a glass transition temperature of at least 57° C. and are dispersible in water at temperatures below about 90° C. The new sulfopolyesters are particularly useful for producing multicomponent fibers in which excellent removability is combined with block resistance.

[0070] In other embodiments, these sulfopolyesters comprising 1,4-cyclohexanedimethanol residues exhibit a glass transition temperature of at least 57° C., 58° C., 59° C., 60° C., 61° C., 62° C., 63° C., 64° C., 65° C., 66° C., 67° C., 68° C., 69° C., or 70° C. and / or less than 120° C., 115° C., 110° C., 105° C., 100° C., 95° C., or 90° C. The intrinsic viscosity may be at least 0.1, 0.15, 0.2, 0.25, or 0.3 and / or less than 0.8, 0.7, 0.6, 0.5, or 0.45 dL / g.

[0071] In another embodiment, these sulfopolyesters containing 1,4-cyclohexanedimethanol contain two diol residues, wherein the diol consists of 1,4-cyclohexanedimethanol and diethylene glycol. In one embodiment, ethylene glycol is not used as the diol. The molar ratio of the residues of diethylene glycol to the residues of 1,4-cyclohexanedimethanol can be less than 1, less than 0.75, less than 0.5, or less than 0.25. The amount of the residues of 1,4-cyclohexanedimethanol in the sulfopolyester can be at least 20, 25, 30, 35, 40, 45, 50, 55, or 60 mole percent and / or not more than 99, 95, 90, 85, or 80 moles. The amount of sulfomonomer in these sulfopolyesters can be at least 4, 5, 6, 7, 8, 8.5, 9, 9.5, 10, 11, 12, 13, or 14 mole percent and / or less than 40, 35, 30, 25, or 20 mole percent. In one embodiment of the present invention, the sulfomonomer is sulfoisophthalic acid.In another embodiment of the present invention, the sulfopolyester comprises residues of one or more dicarboxylic acids derived from terephthalic acid, isophthalic acid, or a combination thereof.

[0072] In another embodiment, these sulfopolyesters containing 1,4-cyclohexanedimethanol residues can form an aqueous dispersion containing at least 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5 weight percent of the sulfopolyester when the sulfopolyester is added to purified water at 90°C with constant stirring for at least 5 minutes.

[0073] In another embodiment of the present invention, the sulfopolyester comprises ethylene glycol residues and diethylene glycol residues. These sulfopolyesters are selected from:

[0074] (1) A sulfopolyester comprising:

[0075] (a) residues of one or more dicarboxylic acids;

[0076] (b) at least 10 mole percent of residues of at least one sulfomonomer; and

[0077] (c) residues of two or more diols, wherein the diols include ethylene glycol and diethylene glycol,

[0078] wherein the sulfopolyester exhibits a glass transition temperature of at least 58°C, wherein the sulfopolyester comprises a molar ratio of diethylene glycol residues to ethylene glycol residues of less than 0.65, wherein the sulfopolyester contains substantially equimolar proportions of acid moiety repeating units (100 mole percent) to hydroxyl moiety repeating units (100 mole percent), and

[0079] wherein all of said mole percents are based on the sum of all acid and hydroxyl moiety repeating units, said sum being equal to 200 mole percent; and

[0080] 2) Amorphous sulfopolyester comprising:

[0081] (a) residues of isophthalic acid;

[0082] (b) residues of terephthalic acid;

[0083] (c) the residue of at least one sulfomonomer;

[0084] (d) residues of ethylene glycol; and

[0085] (e) residues of diethylene glycol,

[0086] wherein the amorphous sulfopolyester exhibits a glass transition temperature of at least 58°C, wherein the amorphous sulfopolyester contains substantially equal molar proportions of acid moiety repeating units (100 mole %) to hydroxyl moiety repeating units (100 mole %), and wherein all said mole percentages are based on the sum of all acid and hydroxyl moiety repeating units, said sum being equal to 200 mole percent.

[0087] These sulfopolyesters comprising ethylene glycol residues and diethylene glycol residues have a glass transition temperature of at least 58°C and are dispersible in water at temperatures below about 90°C. These sulfopolyesters are particularly useful in the production of multicomponent fibers where excellent removability is combined with block resistance. In other embodiments of the invention, these sulfopolyesters exhibit a glass transition temperature of at least 59°C, 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C or 70°C and / or less than 120°C, 115°C, 110°C, 105°C, 100°C, 95°C or 90°C.

[0088] The molar ratio of diethylene glycol residues to ethylene glycol residues can be less than 0.65, 0.6, 0.55, 0.5, 0.45, or 0.4. The intrinsic viscosity can be at least 0.1, 0.15, 0.2, 0.25, or 0.3 and / or less than 0.8, 0.7, 0.6, 0.5, or 0.45 dL / g. In one embodiment, the sulfopolyester does not contain any ethylene glycol residues. In addition, the sulfopolyester can contain two diol residues, wherein the diol residues consist of ethylene glycol residues and diethylene glycol residues. The amount of ethylene glycol residues in the sulfopolyester can be at least 20, 25, 30, 35, 40, 45, 50, 55, or 60 mole percent and / or no more than 99, 95, 90, 85, or 80 mole percent.

[0089] In another embodiment of the present invention, the sulfopolyester may contain residues of one or more dicarboxylic acids derived from terephthalic acid, isophthalic acid, or a combination thereof. The amount of terephthalic acid residues may be at least 20, 25, 30, 35, 40, 45, 50, 55, or 60 mole percent and / or no more than 99, 95, 90, 85, or 80 mole percent of the residues of terephthalic acid. The amount of isophthalic acid residues may be at least 5, 10, 15, 20, 25, 30, 35, or 40 mole percent and / or no more than 99, 95, 90, 85, or 80 mole percent. In another embodiment, the sulfopolyester does not contain any isophthalic acid residues.

[0090] The sulfopolyester may contain at least 10, 11, 12, 13, or 14 mole percent and / or less than 40, 35, 30, 25, or 20 mole percent sulfomonomer. In one embodiment, the sulfomonomer is sulfoisophthalic acid.

[0091] These sulfopolyesters containing ethylene glycol residues and diethylene glycol residues may be amorphous. In addition, they may not exhibit a DSC melting point obtained with a dual heat scan, wherein the heating curve is from 0 to 280°C at 10°C / min.

[0092] These sulfopolyesters can also form aqueous dispersions containing at least 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 or 5 weight percent of the sulfopolyester when the sulfopolyester is added to purified water at 90°C with constant stirring for at least 5 minutes.

[0093] In another embodiment of the present invention, a sulfopolyester with low dispersion viscosity may be used. The low dispersion viscosity sulfopolyester is at least one selected from the following:

[0094] (1) A sulfopolyester comprising:

[0095] (a) residues of one or more dicarboxylic acids;

[0096] (b) at least 4 mole percent and less than 8.5 mole percent of residues of at least one sulfomonomer; and

[0097] (c) residues of one or more diols,

[0098] wherein the sulfopolyester comprises a ratio of carboxylate end groups to acid end groups of at least 0.6, wherein said sulfopolyester comprises a substantially equimolar ratio of acid moiety repeating units (100 mole percent) to hydroxy moiety repeating units (100 mole percent), and wherein all said mole percents are based on the sum of all acid and hydroxy moiety repeating units, said sum being equal to 200 mole percent;

[0099] (2) A sulfopolyester comprising:

[0100] (a) residues of one or more dicarboxylic acids;

[0101] (b) greater than 8.5 mole percent of residues of at least one sulfomonomer; and

[0102] (c) residues of one or more diols,

[0103] wherein the sulfopolyester comprises a ratio of carboxylate end groups to acid end groups of at least 0.35, wherein said amorphous sulfopolyester comprises a substantially equimolar ratio of acid moiety repeating units (100 mole percent) to hydroxy moiety repeating units (100 mole percent), and wherein all said mole percents are based on the sum of all acid and hydroxy moiety repeating units, said sum being equal to 200 mole percent; and

[0104] (3) A sulfopolyester comprising:

[0105] (a) residues of one or more dicarboxylic acids;

[0106] (b) greater than 8.5 mole percent of residues of at least one sulfomonomer; and

[0107] (c) residues of one or more diols,

[0108] wherein the sulfopolyester comprises carboxylate end groups in an amount of at least 12 µeq / g, wherein an aqueous dispersion comprising 25 weight percent of the sulfopolyester exhibits a dispersion viscosity at 22°C of at least 30 cP and less than 100 cP, wherein the sulfopolyester comprises substantially equimolar proportions of acid moiety repeating units (100 mole percent) and hydroxy moiety repeating units (100 mole percent), and wherein all said mole percents are based on the sum of all acid and hydroxy moiety repeating units, said sum being equal to 200 mole percent.

[0109] To determine the amount of carboxylate end groups and acid end groups of the sulfopolyesters, titrations were performed on a titrator (904 Titrando, Metrohm AG, US) equipped with Tiamo software and a pH electrode (DG116-solvent, Mettler Toledo, US) as a sensing probe. The acid of the sample was titrated with a tetrabutylammonium hydroxide solution in methanol (TBAOH, 0.1 N). The base of the sample was titrated with hydrochloric acid (HCl, 0.1 N) in IPA. The total acid from the sample that had been protonated (titrated) with excess HCl was titrated by TBAOH.

[0110] About 2.0 g of sample was weighed into the titration cell and dissolved in 30 ml of N-methyl-2-pyrrolidone (NMP) with stirring at room temperature. 15 ml of dichloroethane (DCE) was added before titration. The sample solution was then titrated with TBAOH or HCl to an endpoint determined by the Tiamo software or manually. For both analyses, a blank solvent was also titrated.

[0111] The acid result is reported as mmol acid / g sample, which is calculated from the volume of TBAOH used at the titration endpoint, its normality and the sample weight. The base result is reported as mmol base / g sample, which is calculated from the volume of HCl used at the titration endpoint, its normality and the sample weight. The total acid is reported as mmol acid / g sample, which is calculated from the volume of TBAOH at the endpoint and the volume of HCl added to the sample, their normalities and the sample weight.

[0112] The low dispersion viscosity sulfopolyesters can have a ratio of carboxylate end groups to acid end groups of at least 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, or 3.6 and / or less than 10, 9, 8, 7, or 6. The sulfopolyesters may have a carboxylate end group content of at least 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 and / or less than 200, 175, 150, 125, or 105 μeq / g. The sulfopolyesters may have an acid end group content of at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 and / or less than 50, 45, 40, 35, 30, 25, or 20 μeq / g.

[0113] In one embodiment of the present invention, the low dispersion viscosity sulfopolyester has an intrinsic viscosity of at least 0.1, 0.15, 0.2, 0.25, or 0.3 and / or less than 0.8, 0.7, 0.6, 0.5, or 0.45 dL / g.

[0114] The sulfopolyesters may contain sulfomonomer residues in an amount of at least 4, 5, 6, 7, 8, 8.5, 9, 9.5, or 10 mole percent and / or less than 25, 20, 19, 18, 17, 16, 15, 14, or 13 mole percent. In one embodiment, the sulfomonomer is sulfoisophthalic acid.

[0115] In another embodiment of the present invention, these sulfopolyesters comprise residues of one or more dicarboxylic acids derived from terephthalic acid, isophthalic acid, or a combination thereof.

[0116] In yet another embodiment, the sulfopolyesters comprise residues of one or more diols derived from ethylene glycol, 1,4-cyclohexanedimethanol, diethylene glycol, or combinations thereof.

[0117] Aqueous dispersions containing 20, 25, 30, 35, 40, 45 or 50 weight percent of these sulfopolyesters exhibit a dispersion viscosity of at least 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 or 95 cP and less than 1,000, 900, 800, 700, 600, 500, 400, 300, 200 or 100 cP at 22° C. Dispersion viscosity is measured at 30° C. on a cone and plate rheometer at 400 rpm using a #1 spindle.

[0118] In an embodiment, the starting material is a composite material comprising fibers.The term "fibers" includes continuous fibers, short fibers, chopped fibers, long fibers, and multicomponent fibers.

[0119] The term "continuous fibers" refers to fibers that are knotted together to produce a hydroentangled nonwoven fabric that has high tear resistance when stretched in two directions. The term "short fibers" refers to fibers cut to a length of 25 mm to 60 mm. The term "chopped fibers" refers to fibers cut to a length of 25 mm or less. The term "long fibers" refers to fibers cut to a length greater than 60 mm.

[0120] The term "multi-component fiber" refers to a fiber prepared by melting two or more fibers forming polymers in a separate extruder and by directing the resulting multiple polymer streams into a spinneret having multiple distribution flow paths but spinning together to form a fiber. Multi-component fibers are sometimes also referred to as combined or bi-component fibers. The polymers are arranged in different sections or regions with substantially constant positioning across the cross section of the combined fiber and extend continuously along the length of the combined fiber. The construction of such multi-component fibers can be, for example, a sheath / core arrangement, in which one polymer is surrounded by another polymer, or can be a side-by-side arrangement, a ribbon or strip arrangement, a pie arrangement, or an "island in the sea" arrangement. For example, multi-component fibers can be prepared by extruding a sulfonic polyester and one or more water-indispersible polymers through a spinneret, respectively, and the spinneret has a profiled or designed cross-sectional geometry such as an "island in the sea" or a segmented pie-shaped structure. Multi-component fibers are typically short fibers, monofilament fibers, or multifilament fibers with a profiled or circular cross section. Most fiber forms are heat-set. Multi-component fibers can include various antioxidants, pigments, and additives as described herein.

[0121] Optionally, prior to washing, the multicomponent fibers may be cut into staple fibers. Short chopped multicomponent fibers (SCMF) are multicomponent fibers cut into lengths of 25 millimeters or less.

[0122] In embodiments, the composite material may contain less than 10 weight (wt) % pigment or filler, based on the total weight of the composite material.

[0123] The method for recovering sulfopolyester described herein comprises washing ( Figure 1 , washing area) for a period of time to remove impurities on the surface of the composite material.

[0124] The term "impurity" or "contaminant" refers to any undesirable substance on the surface of the composite material. Impurities or contaminants may be naturally occurring or added during the process of recycling the sulfopolyester, or added during the manufacture of the composite material comprising the sulfopolyester. Examples of ingredients (additives) added during the manufacturing process may include oils, slip agents, fillers, surface friction modifiers, light and heat stabilizers, extrusion aids, antistatic agents, colorants, dyes, pigments, fluorescent brighteners, antimicrobial agents, anti-counterfeiting labels, antioxidants, hydrophobic and hydrophilic enhancing agents, viscosity modifiers, toughening agents, adhesion promoters, etc.

[0125] The term "solvent composition" or "washing solvent" refers to a composition comprising one or more solvents and other components. For example, the solvent composition can include water, a surfactant, and can include a small amount of an organic solvent. Examples of surfactants include anionic surfactants, nonionic surfactants, and the like. Examples of organic solvents include alcohols, acetone, ketones, ethers, esters, and the like. In an embodiment, the solvent composition consists essentially of or consists of water.

[0126] In embodiments, washing includes washing the composite material so that the washing solvent moves through the composite material, for example, by mixing, stirring and / or flowing the washing solvent through the composite material, passing the composite material through the washing solvent, and / or scrubbing the composite material with the washing solvent. Washing is performed with shear force. Machines suitable for washing composite materials include, but are not limited to, washing machines, piston flow conduits, mixing tanks, stirring vessels, vacuum belt filters, vacuum drum filters, intermittent vacuum filters, and moving belts. It is also possible to wash the composite material by passing it through a container or tank containing a washing solvent. The direction of the composite material flow can be opposite to the direction of the washing solvent flow, thereby allowing continuous countercurrent washing. The washing residence time can be 15 seconds to 15 minutes, 20 seconds to 12 minutes, 30 seconds to 10 minutes, 1 minute to 8 minutes, 1 minute to 5 minutes, or 1 minute to 3 minutes. In one embodiment, washing includes separating the washing mother liquor from the solid in the washing region. Examples of machines for implementing the dehydration step include, but are not limited to, centrifuges, filters, gravity drainage containers, gravity drainage moving belts, etc. Centrifuges include, but are not limited to, decanter centrifuges, perforated basket centrifuges, and / or pusher centrifuges. Filters include, but are not limited to, vacuum belt filters, pressurized drum filters, vacuum suction filters, and / or rotary vacuum drum filters.

[0127] In embodiments, the wash temperature is from 20°C to 60°C, from 30°C to 60°C, from 40°C to 60°C, or from 50°C to 60°C.

[0128] Washing the composite material with the wash solvent composition produces a washed composite material and a wash liquor.

[0129] After washing, the washed composite is ready for opening. In an embodiment, the composite is mixed with treated water prior to opening. The term "treated water" refers to water that has been treated to remove multivalent cations such as magnesium and calcium so that it does not substantially inhibit the opening of the washed composite. Figure 2 ) and SCMF ( Figure 3 The term "treated water" for recovering the sulfopolyester refers to the treated aqueous stream 103 described later in this disclosure. The treated water is soft water and has a polyvalent cation concentration of 0 to 60 ppm.

[0130] The composite material is opened at a temperature above 60°C ( Figure 1 , opening zone). The opening process includes contacting the composite material with water at a temperature of 61°C to 140°C, 65°C to 135°C, 70°C to 130°C, 75°C to 125°C, 80°C to 120°C, 80°C to 115°C, 80°C to 110°C, 80°C to 105°C, 80°C to 100°C, or 80°C to 90°C. The residence time in the opening zone can be 10 seconds to 10 minutes, 20 seconds to 8 minutes, 20 seconds to 5 minutes, 20 seconds to 4 minutes, 20 seconds to 3 minutes, 20 seconds to 2 minutes, or 20 seconds to 1 minute.

[0131] The composite is opened with shear force. In embodiments, the opening of the composite includes mixing and / or stirring with shear force to open the composite. During this opening, the composite is opened and the sulfopolyester in the composite is diffused or dispersed in the hot water to form an aqueous dispersion containing the sulfopolyester. In addition, one or more non-dispersible polymers present are released and separated from the aqueous dispersion containing the sulfopolyester ( Figure 1 , aqueous dispersions and non-dispersible polymers).

[0132] The term "aqueous dispersion" refers to a sulfopolyester that has been dispersed in water and no further process steps have been taken to increase the concentration of the sulfopolyester. In embodiments, the first and second mother liquors described subsequently ( Figure 2 and Figure 3 ) include aqueous dispersions of sulfopolyesters.

[0133] Optionally, the aqueous dispersion is filtered in a secondary filtration system or zone prior to recovery of the sulfopolyester. Filtration removes any solids remaining in the aqueous dispersion so that they do not disrupt normal operation of the equipment in subsequent steps, such as clogging recovery zones including the first concentration zone. Suitable equipment for the secondary filtration zone includes, but is not limited to, one or more of pleated cartridge filters, leaf filters, candle filters, intermittent pressure filters, intermittent vacuum filters, vacuum drum filters, continuous pressure filters, strainers, and the like. Pre-filtration may also be performed using a centrifuge to remove any solids that are 0.5 microns or larger.

[0134] Next, water is removed from the aqueous dispersion to recover the sulfopolyester ( Figure 1 , recovery zone). Water may be removed from the aqueous dispersion by evaporation or by precipitation to produce a recovered sulfopolyester. The term "recovered sulfopolyester" refers to a sulfopolyester obtained by the process described herein including a washing step and may be in the form of a solid or concentrated sulfopolyester dispersion containing some moisture. The recovered sulfopolyester may also be in the form of a polymer melt.

[0135] Water can be evaporated from the aqueous dispersion by applying heat and / or vacuum to the dispersion. Apparatus for evaporating water include, but are not limited to, thin film evaporators, lifting film plate evaporators, rising film evaporators, falling film evaporators, natural circulation evaporators, vented extruders, or List kneaders. List kneaders include vented extruders for evaporating water from the aqueous dispersion fed into the kneader and kneading elements for kneading the viscous concentrate formed after the evaporation of the water to form a polymer melt.

[0136] Water may also be evaporated from the aqueous dispersion to obtain sulfopolyester solids. The term "sulfopolyester solids" refers to a sulfopolyester in solid form that contains some moisture. The sulfopolyester solids have a moisture content of less than 5 wt % relative to the total weight of the solids. In embodiments, the moisture content is less than 4 wt %, 3 wt %, 2 wt %, 1 wt % or 0.5 wt % relative to the total weight of the solids.

[0137] In embodiments, water may also be effectively removed by using a membrane filtration system to obtain recovered sulfopolyester in the form of a concentrated sulfopolyester dispersion. The term "membrane" or "filter" refers to a thin film-like structure that separates two fluids. It acts as a selective barrier, allowing some particles or chemicals to pass through, but not others. A membrane is a layer of material that acts as a selective barrier between two phases and remains impermeable to a particular particle, molecule, or substance when exposed to a driving force. Some components are allowed to pass through the membrane into the permeate stream, while other components are retained by the membrane and accumulate in the retentate stream.

[0138] Examples of membrane filtration systems include ultrafiltration systems, microfiltration systems, nanofiltration systems, or reverse osmosis systems. Nanofiltration is a cross-flow filtration technology between ultrafiltration and reverse osmosis. Nanofiltration membranes are typically rated by molecular weight cutoff (MWCO), which is defined as the smallest particle that will pass through the membrane as permeate, with retention of larger particles greater than 90%. Nanofiltration MWCOs are typically less than 1000 atomic mass units (Daltons). Ultrafiltration is a cross-flow filtration technology between nanofiltration and microfiltration. Ultrafiltration membranes are typically rated by MWCO. Ultrafiltration MWCOs are typically 10 3 -10 6 Atomic mass unit (Dalton).

[0139] The term "concentrated sulfopolyester dispersion" refers to an aqueous dispersion that has been further treated to remove water to increase the concentration of the sulfopolyester. The sulfopolyester in the concentrated dispersion is from 1 wt % to 40 wt %, from 1 wt % to 35 wt %, from 5 wt % to 30 wt %, from 10 wt % to 30 wt %, from 15 wt % to 30 wt %, from 20 wt % to 30 wt %, or from 25 wt % to 30 wt % relative to the total weight of the concentrated sulfopolyester dispersion.

[0140] In embodiments, heat may be applied to the concentrated sulfopolyester dispersion to obtain a polymer melt that contains very little water and forms a solid sulfopolyester upon cooling.

[0141] In an embodiment, the recovered sulfopolyester is in the form of a dispersion comprising the recovered sulfopolyester and a solvent composition, and the dispersion comprises 0.01 wt % to 5 wt % impurities relative to the total weight of the dispersion. The dispersion may be a concentrated recovered sulfopolyester dispersion. The dispersion may also be diluted with water in a volume ratio of 1:1, 1:2, 1:3, 1:4, 1:5, 1:10, 1:20, 1:30, 1:50, or 1:100.

[0142] In embodiments, the recycled sulfopolyester is a washed (pre-washed) recycled sulfopolyester dispersion comprising the recycled sulfopolyester and a solvent composition; wherein the impurity level of the dispersion is from 0.01% to 5% relative to the total weight of the dispersion. The term "washed recycled sulfopolyester" or "pre-washed recycled sulfopolyester" refers to a sulfopolyester that has been recovered from a material and the recovery process includes a washing (pre-washing) step prior to opening and / or mixing with treated water.

[0143] In embodiments, the amount of impurities in the dispersions described herein is from 0.1 wt % to 4.5 wt %, from 0.1 wt % to 4.0 wt %, from 0.1 wt % to 3.5 wt %, from 0.1 wt % to 3.0 wt %, from 0.1 wt % to 2.5 wt %, from 0.1 wt % to 2.0 wt %, from 0.1 wt % to 1.5 wt %, from 0.1 wt % to 1.0 wt %, from 0.1 wt % to 0.5 wt %, from 0.1 wt % to 0.4 wt %, from 0.1 wt % to 0.3 wt %, or from 0.1 wt % to 0.2 wt %, relative to the total weight of the dispersion.

[0144] In embodiments, the recycled sulfopolyester is a washed (pre-washed) recycled sulfopolyester dispersion comprising the recycled sulfopolyester and a solvent composition, and having an impurity concentration reduced by at least 80%, 82%, 85%, 87%, 90%, 92%, 95%, or 97% or more compared to a recycled sulfopolyester dispersion that has not been pre-washed.

[0145] In embodiments, the recovered sulfopolyester is a washed (pre-washed) recovered sulfopolyester dispersion, wherein the dispersion comprises essentially a two-phase system. The dispersion comprises primarily an aqueous phase and a sulfopolyester phase. In embodiments, the dispersion may contain impurities as described above. Depending on the impurity, for example, if the impurity is oil, another phase may be present containing a small amount of the impurity.

[0146] The recycled sulfopolyesters described herein include washed (or pre-washed) sulfopolyesters in solid form comprising from 0.01 wt % to 5 wt % impurities, or comprising at least an 80% or more reduced impurity concentration compared to a recycled sulfopolyester dispersion that has not been pre-washed.

[0147] The washed (pre-washed) recovered sulfopolyester dispersion comprises one or more of the following properties: clear film quality compared to the sulfopolyester dispersion without pre-washing; average dispersed particle size of 10-500 nm, 20-400 nm, 20-300 nm, 20-200 nm or 20-100 nm; particle size distribution of 1-1000 nm, 1-750 nm, 1-500 nm, 1-250 nm or 1-100 nm; solution viscosity of 50-1000 cp, 50-750 cp, 50-500 cp, 50-250 cp or 50-100 cp; cyclic oligomers less than 2%; molecular weight of 2-20 kDa, 3-15 kDa or 4-10 kDa; and a multivalent ion content of less than 60 ppm by weight, less than 40 ppm by weight, less than 20 ppm by weight or less than 10 ppm by weight. Furthermore, the sulfopolyester dispersion recovered after washing (pre-washing) exhibited a clear drawdown film.

[0148] The sulfopolyester recovered by washing (pre-washing) has a glass transition temperature (Tg) of 25°C to 120°C, 30°C to 120°C, 35°C to 120°C, 40°C to 120°C, 50°C to 120°C, 60°C to 120°C, 65°C to 120°C, 70°C to 120˚C, 75°C to 120°C, or 80°C to 120°C.

[0149] The recovered sulfopolyester is both hydrophilic and hydrophobic. The recovered sulfopolyester comprises: (A) residues of one or more dicarboxylic acids; (B) 4-40 mol%, 4-40 mol%, 5-30 mol%, 6-20 mol%, 7-15 mol%, or 8-10 mol% of residues of at least one sulfonic monomer, based on the total repeating units, comprising two functional groups and one or more sulfonate groups attached to an aromatic ring or an alicyclic ring, wherein the functional groups are hydroxyl, carboxyl, or a combination thereof; and (C) one or more diol residues, wherein the one or more diol residues are 10-100 mol%, 10-90 mol%, 10-80 mol%, 15-75 mol%, 20-60 mol%, 20-55 mol%, 20-50 mol%, or 20-40 mol%, based on the total diol residues, of the structure H(OCH2CH2) nOH, wherein n is an integer from 2 to 500, 2 to 100, 2 to 75, 2 to 50, 2 to 25, 2 to 20, 2 to 15, 2 to 10, 2 to 9, 2 to 8, 2 to 7, 2 to 6, 2 to 5, or 2 to 4; and 0-25 mol%, 0-20 mol%, 0-15 mol%, 0-10 mol%, 0-5 mol%, 0-4 mol%, 0-3 mol%, 0-2 mol%, or 0-1 mol% of the residue of a branching monomer having 3 or more functional groups, wherein the functional groups are hydroxyl, carboxyl, or a combination thereof, based on the total repeating units.

[0150] Dicarboxylic acids include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids and / or aromatic dicarboxylic acids. Examples of such dicarboxylic acids include, but are not limited to, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, itaconic acid, 1,4-cyclohexanedicarboxylic acid, 2,6-naphthalene dicarboxylic acid, phthalic acid, terephthalic acid and isophthalic acid.

[0151] The glycol includes aliphatic glycol, alicyclic glycol and / or aralkyl glycol. Examples include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol and polyalkylene glycol. Other suitable glycols include alicyclic glycols having 6 to 20 carbon atoms and aliphatic glycols having 3 to 20 carbon atoms. Specific examples of such diols are ethylene glycol, propylene glycol, 1,3-propylene glycol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 2,2-dimethyl-1,3-propylene glycol, 2-ethyl-2-butyl-1,3-propylene glycol, 2-ethyl-2-isobutyl-1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, diethanol, 2,2,4-trimethyl-1,6-hexanediol; 2,2,4-trimethyl-1,6-hexanedio-1thiodiethanol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol and terephthalimethanol. The sulfopolyesters may also contain mixtures of diols.

[0152] Diols also include multifunctional alcohols (polyols). Examples of polyols include neopentyl glycol; butanediol; 1,4-butanediol, hexanediol; 1,6-hexanediol; polyglycols such as diethylene glycol or triethylene glycol, etc.; triols such as glycerol, trimethylolethane, trimethylolpropane, etc.; and other higher functionality alcohols, such as pentaerythritol, sorbitol, mannitol, etc.

[0153] In an embodiment, the sulfonic monomer comprising two functional groups and one or more sulfonate groups comprises a salt of a sulfoisophthalate moiety. The sulfoisophthalate moiety is derived from a sulfoisophthalic acid comprising a metal sulfonate group. The metal ion of the metal sulfonate group comprises Na+ , K + or Li + In embodiments, the recovered sulfopolyester comprises a salt of a sulfoisophthalate moiety. The salt of the sulfoisophthalate moiety may be derived from sodium 5-sulfoisophthalate or an ester thereof.

[0154] The methods described herein advantageously tend not to degrade the sulfopolyester such that the recovered sulfopolyester exhibits an average molecular weight of at least 50% to 99%, 55% to 95%, 60% to 90%, 65% to 90%, 70% to 90%, 75% to 90%, 80% to 90%, 85% to 90% of the molecular weight of at least the sulfopolyester present in the composite material.

[0155] In embodiments, each step of the process for recovering sulfopolyesters described herein may be performed in a separate zone, such as Figure 1 , Figure 2 and Figure 3 In addition, mixing with treated water and opening can be carried out in the same zone, as described below. Further, the method, in particular washing and opening, can be carried out as a continuous flow process or as a batch process.

[0156] Figure 2 A method of producing a sulfopolyester concentrate stream 702 and / or 903 containing recovered sulfopolyester is shown. Figure 2As shown in, the method includes: (A) contacting a sulfopolyester composite solid stream 101 with a washing solvent composition 201 in a washing zone 200 to remove surface impurities and produce a washing mother liquor stream 202 and a washed sulfopolyester (SFP) composite solid stream 203; wherein the sulfopolyester composite solid in the stream 203 comprises a water-dispersible sulfopolyester and a water-indispersible polymer that is immiscible with the water-dispersible sulfopolyester; (B) contacting the washed sulfopolyester composite solid stream 203 with a treated water stream 103 in a mixing zone 300 to produce a sulfopolyester composite slurry stream 301; (C) contacting the SFP composite slurry 301 with a heated aqueous stream 801 in an opening zone 400 to remove a portion of the water-dispersible sulfopolyester to produce an opened solid slurry 401; wherein the heated aqueous stream 801 is at a temperature above 60°C; wherein the heated aqueous stream 801 is at a temperature above 60°C; wherein the heated aqueous stream 801 is at a temperature above 60°C; wherein the heated aqueous stream 801 is at a temperature above 60°C. The opened solid slurry 401 comprises water, non-dispersible polymer solids and water-dispersible sulfopolyester; and (D) routing the opened solid slurry 401 to a first solid-liquid separation (SLS) zone 500 to produce an opened solid stream 503 and a first mother liquor stream 501; wherein the first mother liquor stream 501 comprises an aqueous dispersion comprising water-dispersible sulfopolyester; (E) routing the first mother liquor stream 501 to a second SLS zone 600 to produce a second mother liquor stream 601; (F) routing the second mother liquor stream 601 to a first concentration zone 700 to produce a first recovered water stream 703 and a first SFP concentrate stream 702 comprising dispersed sulfopolyester and water; and (G) optionally routing the second mother liquor stream 601 and / or at least a portion of the first SFP concentrate stream 702 to a second concentration zone 900 to produce a second SFP concentrate stream 903.

[0157] In the implementation scheme, Figure 2 The mixing zone 300 and the opening zone 400 shown in FIG. 4 can be combined into a single unit operation.

[0158] The treated aqueous stream 103 for use in the method can be produced by conveying the aqueous stream 102 to an aqueous treatment area 1000 to produce a treated aqueous stream 103. The aqueous stream comprises water and is treated to remove polyvalent cations from the water. Removing polyvalent metal cations from the aqueous stream 102 is a function of the aqueous treatment area 1000. In embodiments, the concentration of polyvalent cations is less than 100 ppm by weight, less than 60 ppm by weight, less than 25 ppm by weight, less than 10 ppm by weight, or less than 5 ppm by weight. The temperature of the stream 103 can be from groundwater temperature to 40°C.

[0159] Treatment of the aqueous stream 102 in the aqueous treatment zone 1000 may be accomplished in any manner known in the art. In an embodiment, the aqueous treatment zone 1000 comprises a distillation apparatus in which water vapor is produced and condensed to produce a treated water (aqueous) stream 103. The water is delivered to a reverse osmosis membrane separation system capable of separating polyvalent metal cations from the water to produce a treated water stream 103. In an embodiment, the water is delivered to an ion exchange resin to produce a treated water stream 103 having an acceptably low concentration of metal cations. Additionally, the water may be delivered to a commercial water softening apparatus to produce a treated water stream 103 having an acceptably low concentration of monovalent and polyvalent metal cations. It is to be understood that any combination of these water treatment options may be employed to achieve the desired treated water characteristics.

[0160] Treated water stream 103 may be sent to any location in the process where it is needed. In embodiments, a portion of stream 103 is sent to first solid-liquid separation (SLS) zone 500 for use as machine wash, filter media wash, and / or washing of solids contained in first solid-liquid separation zone 500.

[0161] In embodiments, at least a portion of the treated aqueous stream 103 is conveyed to a heat exchanger zone 800 to produce a heated aqueous stream 801 and at least a portion of the treated aqueous stream 103 is conveyed to a mixing zone 300. Streams that may feed the heat exchanger zone 800 include the treated aqueous stream 103, a portion of the first recovered water stream 703, a portion of the first mother liquor stream 501, and a portion of the second mother liquor stream 601. One function of the heat exchanger zone 800 is to produce a heated aqueous stream 801 at a specific and controlled temperature.

[0162] Any device known in the art for controlling the temperature of logistics 801 may be used, including but not limited to any heat exchanger that uses steam to provide a portion of the required energy, any heat exchanger that uses a heat transfer fluid to provide a portion of the required energy, any heat exchanger that uses an electric heating element to provide a portion of the required energy, and any container or tank with direct steam injection (wherein the steam condenses and the condensate is mixed with a water feed to heat the exchanger area 800).

[0163] The sulfopolyester composite material stream 101 is conveyed to a washing zone 200 to facilitate washing at least a portion of the impurities off the surface of the sulfopolyester composite material stream solids. Impurities or contaminants may be naturally generated or added during the process of recovering the sulfopolyester, or added during the manufacture of the material comprising the sulfopolyester. Examples of ingredients (additives) added during the manufacturing process may include oils, slip agents, fillers, surface friction modifiers, light and heat stabilizers, extrusion aids, antistatic agents, colorants, dyes, pigments, fluorescent whitening agents, antimicrobial agents, anti-counterfeiting marks, antioxidants, hydrophobic and hydrophilic enhancers, viscosity modifiers, toughening agents, adhesion promoters, etc. It is desirable to remove these surface impurities before opening to prevent impurities from contaminating the second mother liquor stream 601 and to prevent impurities from concentrating in the first concentration zone 700 and causing the impurities to concentrate in the recovered sulfopolyester stream 702, which would make the stream 702 unsuitable for certain end-use applications. For example, the presence of oil in the recovered sulfopolyester concentrate may result in poor film-forming properties.

[0164] The temperature of wash solvent stream 201 may be from 20°C to 60°C, from 30°C to 60°C, from 40°C to 60°C, or from 50°C to 60°C.

[0165] The composition of the wash solvent stream 201 comprises water. A surfactant and or organic solvent may also be present in small concentrations to help wash away certain impurities. For example, a surfactant is typically required to wash oil from SFP composite solids. In an embodiment, the wash solvent (solvent composition) consists essentially of or consists of water.

[0166] In embodiments, the SFP composite solid stream 101 may be in the physical form of cut fibers, granular solids, discrete particles, discrete solid objects, and the like. In embodiments, the concentration of the SFP composite solids in the wash zone is controlled so that the mixture of the wash solvent 201 and the SFP composite solid stream 101 is a pumpable slurry. In other embodiments, the concentration of the SFP composite solids in the wash zone is controlled so that there is enough wash solvent to wash at least a portion of the impurities away from the SFP composite solids. In still other embodiments, it is desirable that the concentration of the SFP composite solids in the wash zone is controlled so that the mixture of the wash solvent 201 and the SFP composite solid stream 101 produces a non-settling mixture in a well-stirred tank. The concentration of the SFP composite solids in the wash zone may be 0.1 wt % to 10 wt %, 0.1 wt % to 8 wt %, 0.1 wt % to 6 wt %, 0.1 wt % to 4 wt %, 0.1 wt % to 3 wt %, and 0.1 wt % to 2 wt %, relative to the total combined weight of streams 101 and 201.

[0167] In washing zone 200, there is the function of washing and dehydrating solid. The washing function involves contacting washing solvent stream 201 and SFP composite solid stream 101 with enough time and shear force so that at least a portion of surface impurities are transferred to the continuous aqueous phase of mixture. The residence time of washing function can be 15 seconds to 15 minutes, 20 seconds to 12 minutes, 30 seconds to 10 minutes, 1 minute to 8 minutes, 1 minute to 5 minutes or 1 minute to 3 minutes. In embodiments, it is desirable that the washing mixture in washing zone 200 keeps fully mixed and substantially uniform without allowing many solids to settle during the washing function. This is to complete with sufficient stirring to keep solids suspended in the continuous phase during the washing function. The dehydration function is after the washing function, and involves solid-liquid separation to remove a large amount of continuous phases containing impurities from solids. The degree of separation of solid and liquid in the dehydration function depends on the size of the equipment used and the solids present. It is desirable to maximize the amount of liquid substances separated from the washing mixture. Typical moisture percentages of the washed SFP composite solids stream 203 can be 10% solids to 85% solids, 20% solids to 85% solids, 30% solids to 85% solids, 40% solids to 85% solids, 50% solids to 85% solids, 10% solids to 75% solids, 20% solids to 75% solids, 30% solids to 75% solids, and 40% solids to 75% solids. In intermittent washing and dewatering, it is understood that multiple sequential washing and dewatering steps may be required to obtain the desired purity of the washed SFP composite solids stream 203.

[0168] The two functions of washing and dewatering can be completed in the same unit operation, or in separate unit operations in both intermittent and continuous equipment. In an embodiment, the SFP composite material is in the form of a continuous fiber, cloth, woven or nonwoven product, which can be washed by passing it through a container or tank containing a washing solvent. In other embodiments, the SFP composite material is in the form of a continuous fiber, cloth, woven or nonwoven product, which can be washed by flowing the washing solvent through the SFP composite solid. In an embodiment, the SFP composite material is in the form of a continuous fiber, cloth, woven or nonwoven product, which can be washed by passing saturated steam through the product or by flooded wash on a vacuum belt or gravity belt filter. Examples of equipment suitable for intermittent washing include intermittent stirred tanks, intermittent stirred containers, etc. Examples of equipment suitable for continuous washing include any continuous stirred container that can provide a substantially non-settling mixture and a desired residence time. The example of the equipment that is applicable to intermittent dehydration comprises vacuum suction filter, pressurized leaf filter, pressurized candle filter, gravity drainage belt filter, vacuum belt filter, vacuum drum filter, intermittent basket centrifuge, washing tank etc. The intermittent equipment that can have washing and dehydration function simultaneously comprises intermittent stirring container such as false bottom reactor (false bottom reactor), filter dryer, stirring suction filter container etc. with perforated discharge port to allow solid-liquid separation. The continuous solid-liquid separation equipment that can have dehydration function includes but is not limited to rotary vacuum filter, vacuum belt filter, continuous pressurized drum filter etc. This type of continuous solid-liquid separation equipment also has short residence time washing capacity, and therefore if the residence time required for washing is 0.25-3 minute, then washing and dehydration function are provided. In these machines, multiple washing zones can be configured in the form of countercurrent or cocurrent with solid.

[0169] In an embodiment, the SFP composite material stream 101 is in the physical form of a woven product, a mat, a felt, a melt-spun product, a nonwoven product, an additive manufacturing product, a molded product, etc. The washing solvent 201 does not form a slurry when in contact with the SFP composite material stream 101, and therefore the solid concentration in the liquid is not limited to those suitable for forming a slurry. The selected equipment must allow sufficient washing solvent contact time and shear force to allow impurities to be removed from the solid surface into the washing mother liquor stream 202. This can be done in a simple stirred intermittent container with repeated washing and drainage cycles until the solid is fully washed. The washing and dehydration functions can also be completed in a continuous device, such as a vacuum belt filter with one or more overflow displacement washes, a perforated conveyor belt including a washing zone and a dehydration zone, etc. The washing residence time of the overflow displacement wash is 0.5 minutes to 5 minutes, 0.5 minutes to 4 minutes, 0.5 minutes to 3 minutes.

[0170] The washed SFP composite solids stream 203 and the treated water stream 103 are conveyed to a mixing zone 300, where the substantially dehydrated solids in stream 203 are re-slurried to form an SFP composite stream 301. Suitable equipment for the mixing zone 300 includes an intermittent mixing vessel or a continuous mixing vessel. The residence time is not limited. The agitation in the tank must be sufficient to produce a substantially uniform slurry that can be pumped. The solids percentage of the SFP composite slurry stream 301 is 0.1 wt % to 10 wt %, 0.1 wt % to 8 wt %, 0.1 wt % to 6 wt %, 0.1 wt % to 4 wt %, 0.1 wt % to 3 wt %, and 0.1 wt % to 2 wt %.

[0171] The SFP composite slurry stream 301 and a portion of the heated treated aqueous stream 801 are conveyed to an opening zone 400 to produce an opened solid slurry 401. One function of the opening zone 400 is to separate the water dispersible polymer from the SFP composite solids such that at least a portion of the water non-dispersible polymer is separated from the water dispersible polymer and becomes suspended in the opened solid slurry 401 comprising the water non-dispersible solids and the dispersed sulfopolyester. In an embodiment, 50 wt % to 100 wt % of the water non-dispersible polymer fibers contained in the SFP composite solids 301 become suspended in the opened solid slurry 401 as water non-dispersible polymer and are no longer part of the SFP composite solids. In embodiments, 75 wt % to 100 wt %, 90 wt % to 100 wt %, or 95 wt % to 100 wt % of the water non-dispersible polymer contained in the SFP composite solids slurry stream 301 becomes suspended in the opened solids slurry 401 as water non-dispersible polymer solids and is no longer part of the SFP composite solids.

[0172] The residence time, temperature and shear force in the opening zone 400 affect the degree of separation of the water dispersible sulfopolyester from the SFP composite solids. The conditions that affect the opening process of the composite solids in the opening zone 400 include residence time, slurry temperature and shear force, wherein the range of water temperature, residence time and amount of shear force applied in the opening zone 400 depends on the need to separate the water dispersible sulfopolyester from the starting composite solids to an extent sufficient to cause the water non-dispersible polymer to become separated and suspended in the continuous water phase of the opened solid slurry 401.

[0173] The temperature of the opening zone 400 can be 61° C. to 140° C., 65° C. to 135° C., 70° C. to 130° C., 75° C. to 125° C., 80° C. to 120° C., 80° C. to 115° C., 80° C. to 110° C., 80° C. to 105° C., 80° C. to 100° C., or 80° C. to 90° C. The residence time in the opening zone 400 can be 10 seconds to 10 minutes, 20 seconds to 8 minutes, 20 seconds to 5 minutes, 20 seconds to 4 minutes, 20 seconds to 3 minutes, 20 seconds to 2 minutes, or 20 seconds to 1 minute.

[0174] Adequate mixing is maintained in the opening zone 400 to maintain suspension of the water-indispersible polymer so that settling is minimized. In an embodiment, the mass per unit time of the water-indispersible polymer that settles in the opening zone 400 is less than 5% of the mass per unit time of the water-indispersible polymer that enters the zone 400, less than 3% of the mass per unit time of the cut water-indispersible polymer that enters the zone 400, or less than 1% of the mass per unit time of the cut water-indispersible polymer that enters the opening zone 400.

[0175] Opening of composite solids in opening zone 400 can be accomplished with any equipment that allows for an acceptable range of residence time, temperature, and mixing. Examples of suitable equipment include, but are not limited to, stirred batch tanks, continuous stirred tank reactors, and pipelines with sufficient flow to minimize solid sedimentation from the slurry. An example of a unit operation for completing the opening of washed composite solids in a continuous device is a vacuum belt filter with one or more overflow displacement washes, a perforated conveyor belt including a washing zone and a dewatering zone, and the like. Another example of a unit operation for completing the opening of composite solids in opening zone 400 is a plug flow reactor, in which the SFP composite slurry 301 is transported to a plug flow device in zone 400, typically an annular pipe or conduit. The residence time of the material in the plug flow device is calculated by dividing the fill volume in the device by the volume flow rate in the device. The velocity of the material in the device is defined by the volume flow rate of the liquid through the device divided by the cross-sectional area of ​​the flow channel.

[0176] The opening area 400 may include a pipe or conduit, wherein the velocity of the material flow in the pipe may be 0.1 ft / sec to 20 ft / sec, 0.2 ft / sec to 10 ft / sec, or 0.5 ft / sec to 5 ft / sec. For the flow of a fluid or slurry in a pipe or conduit, the Reynolds number Re is a dimensionless number that can be used to describe the turbulence or motion of a fluid vortex that is irregular in both direction and time. For flow in a pipe or tube, the Reynolds number (Re) is defined as:

[0177]

[0178] in:

[0179] D H is the hydraulic diameter of the pipe; L, (meters);

[0180] Q is the volume flow rate (m 3 / s);

[0181] A is the cross-sectional area of ​​the pipe (m 2 ).

[0182] V is the average velocity of the object relative to the fluid (SI units: m / s);

[0183] µ is the dynamic viscosity of the fluid (Pa∙s or N∙s / m 2 or kg / (m∙s));

[0184] ν is the kinematic viscosity (ν = µ / ρ) (m 2 / s)

[0185] ρ is the density of the fluid (kg / m 3 ).

[0186] For flow in a pipe of diameter D, experimental observations show that for fully developed flow, laminar flow occurs when Re < 2000, and turbulent flow occurs when Re > 4000. In the interval between 2300 and 4000, both laminar and turbulent flow are possible ("transitional" flow), depending on other factors such as pipe roughness and flow uniformity.

[0187] The opening area 400 may include a pipe or conduit to facilitate the opening process, and the Reynolds number for flow through the pipe or conduit in the composite solid opening area 400 may be 2,100 to 6,000, 3,000 to 6,000, or 3,500 to 6,000. In an embodiment, the opening area 400 may include a pipe or conduit to facilitate the opening process, and the Reynolds number for flow through the pipe or conduit is at least 2,500, at least 3,500, or at least 4,000.

[0188] The opening zone 400 can be implemented in a pipe or conduit containing a mixing device inserted in the pipe or conduit. The device can include an in-line mixing device. The in-line mixing device can be a static mixer without moving parts. In an embodiment, the in-line mixing device includes moving parts. In a non-limiting manner, such elements are mechanical devices, and their purpose is to apply more mixing energy to the heated SFP composite slurry 301 than that obtained by flowing through the pipe. The device can be inserted at the beginning of a pipe section, the end of a pipe section, or at any position in the pipe flow path as a fiber opening zone.

[0189] The opened solid slurry stream 401 comprising water non-dispersible polymer, water and water dispersible sulfopolyester can be conveyed to a first solid-liquid separation zone 500 to produce an opened solid product stream 503 comprising opened solids, a first mother liquor stream 501 and a wash liquor stream 502. In embodiments, the first mother liquor stream 501 comprises an aqueous dispersion of the sulfopolyester.

[0190] The weight percent of solids in the opened solid slurry 401 may be 0.1 weight percent to 20 weight percent, 0.3 weight percent to 10 weight percent, 0.3 weight percent to 5 weight percent, or 0.3 weight percent to 2.5 weight percent.

[0191] Separating the loosened solid product stream 503 from the loosened solid slurry 401 can be accomplished by any method known in the art. In an embodiment, a wash stream 103 comprising water is conveyed to the first solid-liquid separation area 500. The wash stream 103 can be used to wash the loosened solids in the first solid-liquid separation (SLS) area 500 and / or the filter cloth medium in the first solid-liquid separation area 500 to produce a wash liquid stream 502. Before entering the first solid-liquid separation area 500, a portion of up to 100% by weight of the wash liquid stream 502 can be mixed with the loosened solid slurry 401. A portion of up to 100% by weight of the wash liquid stream 502 can be conveyed to the second SLS area 600. The wash liquid stream 502 may contain some composite solids. The grams of composite solid matter that passes through the filter medium having an opening up to 2000 microns in the first solid-liquid separation area 500 is 1-2 grams / (cm 2 In an embodiment, the filter openings in the filter medium in the first solid-liquid separation region 500 may be 43 μm to 3000 μm, 100 μm to 2000 μm, or 500 μm to 2000 μm.

[0192] The separation in the first SLS zone 500 can be accomplished by a single or multiple solid-liquid separation devices, for example, by one or more solid-liquid separation devices operating in intermittent and / or continuous modes. Suitable solid-liquid separation devices in the first solid-liquid separation zone 500 can include, but are not limited to, at least one of the following: a perforated basket centrifuge, a continuous vacuum belt filter, an intermittent vacuum suction filter, an intermittent perforated settling tank, a twin wire dewatering device, a continuous horizontal belt filter with a compression zone, a non-vibrating inclined screen device with a wedge-shaped mesh filter medium, a continuous vacuum drum filter, a dewatering conveyor belt, a decanter centrifuge, an intermittent centrifuge, and the like.

[0193] In an embodiment, the first solid-liquid separation area 500 includes a double-wire dewatering device, in which the loosened solid slurry 401 is transported to a conical gap between a pair of traveling filter cloths traveling in the same direction. In the first area of ​​the double-wire dewatering device, water is discharged from the loosened solid slurry 401 due to gravity and the very narrow gap between the two moving filter cloths. In the downstream area of ​​the double-wire dewatering device, the two filter cloths and the loosened solid matter between the two filter cloths are compressed once or multiple times to mechanically reduce the moisture in the loosened solid matter. Mechanical dewatering can be accomplished by passing the two filter cloths and the contained loosened solid matter through at least one set of rollers, which apply a compressive force to the two filter cloths and the loosened solid matter. Mechanical dewatering can also be accomplished by passing the two filter cloths and the loosened solid matter between at least one set of pressure rollers.

[0194] The force applied by the mechanical dewatering of each group of pressure rollers can be 25-300 pounds / (linear inches of filter media width), 50-200 pounds / (linear inches of filter media width) or 70-125 pounds / (linear inches of filter media width). Along with the two filter cloths separating and separating in the solid discharge area of ​​the device, the solid product stream 503 through opening is discharged from the double-net dewatering device. The thickness of the solid material through opening discharged can be 0.2 inches to 1.5 inches, 0.3 inches to 1.25 inches or 0.4 inches to 1 inch. In embodiments, the washing stream comprising water is continuously applied to the filter medium. In embodiments, the washing stream comprising water is periodically applied to the filter medium.

[0195] The first SLS zone 500 may include a belt filter arrangement including a gravity drainage zone and a pressure dewatering zone. The opened solid slurry 401 is conveyed to a conical gap between a pair of moving filter cloths traveling in the same direction, first through the gravity drainage zone, and then through a pressure dewatering zone or pressing zone including a complex arrangement of rollers. As the belt feeds through the rollers, water is squeezed from the solids. When the belt passes the last pair of rollers in the process, the filter cloths separate and the solids leave the belt filter arrangement.

[0196] In an embodiment, at least a portion of the water contained in the first mother liquor stream 501 comprising water and water dispersible sulfopolyester polymer is recovered and recycled. The first mother liquor stream 501 can be recycled to the first solid-liquid separation zone 500. Depending on the efficiency of the first liquid separation zone in removing water non-dispersible polymers, the first mother liquor stream 501 can be recycled to the opening zone 400 or the heat exchanger zone 800 before being conveyed to zone 400. Due to breakthrough and washing, such as machine washing, the first mother liquor stream 501 may contain a small amount of solids including water non-dispersible polymers. The grams of water non-dispersible polymer material passing through the filter medium having openings up to 2000 microns in the first solid-liquid separation zone is 1-2 grams / (cm 2 It is desirable to minimize water non-dispersible polymer solids in the first mother liquor stream 501 prior to conveying the stream 501 to the first concentrating zone 700 and the heat exchange zone 800 where the water non-dispersible polymer solids can collect and accumulate in the zone and negatively impact its function.

[0197] The SLS zone 600 can be used to remove at least a portion of the water non-dispersible polymer solids present in the first mother liquor stream 501 to produce a second wet cake stream 602 comprising water non-dispersible polymers and a second mother liquor stream 601 comprising water and water dispersible sulfopolyester.

[0198] In embodiments, the second mother liquor stream 601 may be sent to the first concentrating zone 700 and or the heat exchanger zone 800, wherein the weight percent of the second mother liquor stream 601 sent to the first concentrating zone 700 may be from 0% to 100% with the balance of the stream sent to the heat exchanger zone 800. The second mother liquor stream 601 may be recycled to the opening zone 400 or the heat exchanger zone 800 before being sent to zone 400. The amount of water-dispersible sulfopolyester in the second mother liquor stream sent to the fiber opening zone 400 may be from 0.01 wt% to 7 wt%, or from 0.1 wt% to 7 wt%, from 0.2 wt% to 5 wt%, or from 0.3 wt% to 3 wt%, based on the weight percent of the second mother liquor stream.

[0199] Any portion of the second mother liquor 601 sent to the first concentration zone is subjected to a separation process to produce a first recovered water stream 703 and a first polymer concentrate stream 702 enriched in water-dispersible sulfopolyester, wherein the weight percentage of water-dispersible sulfopolyester in the first polymer concentrate stream 702 can be 1 wt % to 40 wt %, 1 wt % to 35 wt %, 5 wt % to 30 wt %, 10 wt % to 30 wt %, 15 wt % to 30 wt %, 20 wt % to 30 wt %, or 25 wt % to 30 wt %, relative to the total weight of the concentrated sulfopolyester dispersion. The first SFP concentrate stream 702 comprises a recovery of sulfopolyester in the composite solids of 75% to 99.9%, 75% to 99%, 80% to 98%, 85% to 97%, 90% to 96%, or 91% to 95%.

[0200] The first recovered water stream 703 may be recycled to the opening zone 400 or the heat exchanger zone 800 before being delivered to zone 400. The amount of water-dispersible sulfopolyester in the second mother liquor stream delivered to the fiber opening zone 400 may be from 0.01 wt % to 7 wt %, or from 0.1 wt % to 7 wt %, from 0.2 wt % to 5 wt %, or from 0.3 wt % to 3 wt %, based on the weight percentage of the second mother liquor stream.

[0201] Water may be removed from the second mother liquor stream 601 in the first concentration zone 700 by any method known in the art to produce the first SFP concentrate stream 702. In an embodiment, the removal of water involves an evaporation process by boiling off the water in an intermittent or continuous evaporation device. For example, one or more thin film evaporators may be used for this application. Membrane technology including ultrafiltration, microfiltration, nanofiltration media may be used to produce the first SFP concentrate stream 702. In an embodiment, a method including an extraction device may be used to extract a water-dispersible polymer from the second mother liquor stream 601 and produce the first SFP concentrate stream 702. It is to be understood that any combination of evaporation, membrane, and extraction steps may be used to separate the water-dispersible sulfopolyester from the second mother liquor stream 601 and produce the first polymer concentrate stream 702. The first SFP concentrate stream 702 may then exit the process.

[0202] Filtration systems including ultrafiltration, microfiltration, and nanofiltration systems may be used to produce the first SFP concentrate stream 702. In embodiments, a process including an extraction device may be used to extract the water-dispersible polymer from the second mother liquor stream 601 and produce the first SFP concentrate stream 702. It should be understood that any combination of evaporation, membrane, and extraction steps may be used to separate the water-dispersible sulfopolyester from the second mother liquor stream 601 and produce the first polymer concentrate stream 702. The first SFP concentrate stream 702 may then exit the process.

[0203] The membrane filtration for concentrating the sulfopolyester can be accomplished in batch or continuous mode. In embodiments, the membrane filtration zone comprises at least one ultrafiltration membrane in batch operation. The aqueous dispersion is conveyed to a sulfopolyester concentration zone comprising at least one nanofiltration, ultrafiltration or microfiltration membrane. The first SFP concentrate stream 702 can be recycled to feed the first concentration zone 700 until the desired sulfopolyester concentration is achieved in stream 702.

[0204] Membrane filtration for concentrating the sulfopolyester can be accomplished in batch or continuous mode. In one embodiment, the first concentrating zone 600 comprises at least one ultrafiltration, microfiltration, or nanofiltration membrane in batch operation. In another embodiment, the first concentrating zone 600 comprises at least one ultrafiltration, microfiltration, or nanofiltration membrane in continuous operation.

[0205] In an embodiment, the first concentration region 700 is implemented in a continuous membrane filtration system including one or more membrane units connected in series relative to the flow path. In an embodiment, each membrane unit includes at least one nanofiltration, microfiltration or ultrafiltration membrane, and may contain multiple parallel nanofiltration, microfiltration or ultrafiltration membranes to achieve the desired membrane filtration area required for the feed rate of logistics 601. In an embodiment, the first concentration region 700 may include a membrane other than an ultrafiltration membrane. For example, region 700 may include two or more membrane units connected in series. Multiple membranes can be used in region 700, and these membranes can operate at different pressures.

[0206] In an embodiment, the first polymer concentrate stream 702 may be conveyed to a second concentrating zone 900 to produce a molten polymer stream 903 comprising a water-dispersible sulfopolyester, wherein the weight percent of the polymer is from 95% to 100%, and to produce a vapor stream 902 comprising water. In an embodiment, 903 comprises a water-dispersible sulfopolyester. Suitable equipment for use in the second concentrating zone 900 includes any equipment known in the art capable of feeding an aqueous dispersion of a water-dispersible polymer and producing a 95% to 100% water-dispersible polymer stream 903. In an embodiment, an aqueous dispersion of a water-dispersible sulfopolyester polymer is fed to the second concentrating zone 902. The temperature of the feed stream is typically less than 100°C.

[0207] The second concentration zone 900 includes at least one device characterized by a jacketed shell containing a rotating conveying screw, wherein the conveying screw is heated with a heat transfer fluid or steam, and includes both conveying and high shear mixing elements. The jacket or shell is vented to allow vapor to escape. The shell jacket can be zoned to allow different temperature set points along the length of the device. During continuous operation, the first polymer concentrate stream 702 contains an aqueous dispersion of a water-dispersible sulfopolyester and is continuously fed to the second concentration zone 900. Within the device, during steady state, the material exists in at least three distinct and different forms. The material first exists in the device as an aqueous dispersion of a water-dispersible sulfopolyester polymer. As the aqueous dispersion of the sulfopolyester polymer moves through the device, water is evaporated due to the heat of the jacket and internal screws. When enough water is evaporated, the material changes to a second form containing a viscous plug at a temperature below the melting temperature of the sulfopolyester polymer. The aqueous dispersion cannot flow through the viscous plug and is confined to the first aqueous dispersion zone of the device. Due to the heat of the jacket, the heat of the internally heated screws, and the heat caused by the mixing shear forces of this high viscosity plug material, substantially all of the water present at this location evaporates, and the temperature rises until the melting temperature of the sulfopolyester is reached, producing a third and final physical form of material comprising molten sulfopolyester polymer in the apparatus. The molten sulfopolyester polymer then exits the apparatus through an extrusion die and is typically cooled and cut into pellets by any means known in the art. It should be understood that the apparatus of the second concentration zone 900 described above can also be operated in a batch mode, wherein the three physical forms of material described above occur throughout the length of the apparatus, but at different times in a sequential order starting with the aqueous dispersion, the viscous plug, and finally the sulfopolyester melt.

[0208] In embodiments, water vapor stream 902 produced in second concentrating zone 900 may be condensed and sent to heat exchanger zone 800, discarded, and / or sent to wash stream 103. In embodiments, water vapor stream 902 comprising water vapor may be sent to heat exchanger zone 800 to provide at least a portion of the energy required to produce the desired temperature of stream 801. Molten polymer stream 903 comprising the sulfopolyester-containing water-dispersible polymer in the molten phase may be cooled to a solid and cut into pellets by any method known in the art.

[0209] Impurities may enter the process and concentrate in the recovered and recycled water. One or more purge streams (603 and 701) may be used to control the impurity concentrations in the second mother liquor 601 and the first recovered water stream 701 to acceptable levels. In embodiments, a portion of the second mother liquor stream 601 may be separated and purged from the process. In embodiments, a portion of the first recovered water stream 701 may be separated and purged from the process.

[0210] In embodiments, when the SFP composite solids are present as cut fibers ( Figure 3 ), the diameter of the starting cut multicomponent fibers in stream 101 affects the degree of separation of the water-dispersible sulfopolyester from the cut multicomponent fibers in fiber opening zone 400. Typical short cut multicomponent fiber types generally have diameters less than 25 microns. Some cut multicomponent fibers may have a larger starting diameter. The time required to separate a desired amount of water-dispersible sulfopolyester from the cut multicomponent fibers increases with increasing cut multicomponent fiber diameter.

[0211] Any equipment known in the art may be used to cut the multicomponent fibers to produce cut multicomponent fiber stream 101 ( Figure 3 ). In an embodiment, the length of the cut fibers in cut multicomponent fiber stream 101 is less than 25 mm. In an embodiment, the length of the cut fibers in cut multicomponent fiber stream 101 is less than 25 mm, less than 20 mm, less than 15 mm, less than 10 mm, or less than 5 mm and greater than 2.5 mm.

[0212] In an embodiment, the method for recovering sulfopolyester from a multicomponent fiber is Figure 3As shown, the method includes producing a microfiber product stream 503, which includes: (A) cutting a multicomponent fiber comprising a sulfopolyester into short fibers having a length of less than 25 mm, wherein the multicomponent fiber comprises a water-dispersible sulfopolyester and a water-indispersible polymer that is immiscible with the water-dispersible sulfopolyester; (B) contacting a chopped multicomponent fiber (SCMF) solid stream 101 with a washing solvent 201 in a washing zone 200 to remove surface impurities and produce a washing mother liquor stream 202 and a washed SCMF solid stream 203; (C) contacting the washed SCMF solid stream 203 with a treated water stream 103 in a mixing zone 300 to produce a SCMF slurry stream 301; (D) contacting the SCMF slurry 301 with a heated aqueous stream 801 in a fiber opening zone 400 to remove a portion of the water-dispersible sulfopolyester to produce an opened SCMF slurry 401; wherein the heated an aqueous stream 801 at a temperature above 60° C.; wherein the opened SCMF slurry 401 comprises water, non-dispersible polymer solids and water-dispersible sulfopolyester; and (E) conveying the opened SCMF slurry 401 to a first solid-liquid separation (SLS) zone 500 to produce a microfiber product stream 503 and a first mother liquor stream 501; wherein the first mother liquor stream 501 comprises an aqueous dispersion of water-dispersible sulfopolyester; (F) conveying the first mother liquor stream 501 to a second SLS zone 600 to produce a second mother liquor stream; (G) conveying the second mother liquor stream to a first concentration zone to produce a first recovered water stream 703 and a first SFP concentrate stream 702 comprising dispersed sulfopolyester and water; and (H) optionally conveying at least a portion of the second mother liquor stream 601 and / or the first SFP concentrate stream 702 to a second concentration zone 900 to produce a second SFP concentrate stream 903.

[0213] In an embodiment, the mixing zone 300 and the opening zone 400 can be combined and completed in a single unit operation. The short-cut multi-component fiber stream 101 is directly conveyed to a single unit operation, where it is mixed with the heated aqueous stream 801 in the fiber opening zone 400. For example, the process of opening the cut multi-component fibers is completed in a mixing device, where the cut multi-component fiber stream 101 and the heated aqueous stream 801 are directly added to the opening zone 400. The mixing device includes, but is not limited to, an intermittent mixing device, a continuous mixing device, a continuous stirred tank reactor (CSTR), a piston flow conduit, etc. The fiber opening zone may include at least one mixing tank. The combined functions of zones 200, 300, and 400 can be completed in a continuous stirred tank reactor. In an embodiment, the combined functions of zones 200, 300, and 400 can be completed in any intermittent or continuous mixing device that can achieve the functional requirements of the residence time, temperature, and mixing shear force required for the proper functions of zones 200, 300, and 400.

[0214] A treated aqueous stream 103 for the method can be produced by conveying the aqueous stream 102 to an aqueous treatment area 1000 to produce a treated aqueous stream 103. The aqueous stream comprises water and is treated to remove polyvalent cations from the water. Removing polyvalent metal cations from the aqueous stream 102 is a function of the aqueous treatment area 1000. In embodiments, the concentration of polyvalent cations is less than 100 ppm by weight, less than 60 ppm by weight, less than 25 ppm by weight, less than 10 ppm by weight, or less than 5 ppm by weight. The temperature of the stream 103 can be from groundwater temperature to 40°C.

[0215] Treatment of the aqueous stream 102 in the aqueous treatment zone 1000 may be accomplished in any manner known in the art. In an embodiment, the aqueous treatment zone 1000 comprises a distillation apparatus in which water vapor is produced and condensed to produce a treated aqueous stream 103. In an embodiment, the water is sent to a reverse osmosis membrane capable of separating monovalent and multivalent metal cations from the water to produce the treated aqueous stream 103. In an embodiment, the water is sent to an ion exchange resin to produce a treated aqueous stream 103 having an acceptably low concentration of metal cations. In addition, the water may be sent to a commercial water softening apparatus to produce a treated aqueous stream 103 having an acceptably low concentration of multivalent metal cations. It is to be understood that any combination of these water treatment options may be employed to achieve the desired characteristics of the treated water.

[0216] Treated aqueous stream 103 may be delivered to any location in the process where it is needed. In embodiments, a portion of stream 103 is delivered to first solid-liquid separation zone 500 for use as a machine wash, filter media wash, and / or wash of solids contained in first solid-liquid separation zone 500.

[0217] In embodiments, at least a portion of the treated aqueous stream 103 is delivered to a heat exchanger region 800 to produce a heated aqueous stream 801, and at least a portion of the treated aqueous stream 103 is delivered to a mixing region 300. The streams that may be fed to the heat exchanger region 800 include the treated aqueous stream 103, a portion of the first recovered water stream 703, a portion of the first mother liquor stream 501, and a portion of the second mother liquor stream 601. One function of the heat exchanger region 800 is to produce a heated aqueous stream 801 at a specific and controlled temperature. The equipment for controlling the temperature of 801 has been described previously and will not be repeated here.

[0218] The SCMF solid stream 101 is conveyed to a washing zone 200 to facilitate washing at least a portion of the impurities from the surface of the SCMF stream solids. The need to remove impurities has been previously described and will not be repeated here.

[0219] The temperature of wash solvent stream 201 may be from 20°C to 60°C, from 30°C to 60°C, from 40°C to 60°C, or from 50°C to 60°C.

[0220] The composition of the wash solvent stream 201 includes water. A small concentration of surfactant and / or organic solvent may also be present to help wash away certain impurities. For example, a surfactant is often required to wash the oil from the SCMF solids. Suitable surfactants include, but are not limited to, anionic surfactants, nonionic surfactants, and the like. Suitable organic solvents include, but are not limited to, alcohols, acetone, ketones, ethers, esters, and the like.

[0221] In embodiments, SCMF solid stream 101 is the physical form of cut fibers. Control the concentration of SCMF in the scrubbing zone so that the mixture of the scrubbing solvent composition 201 and the SCMF solid stream 101 is a pumpable slurry. It is also desirable to control the concentration of the SCMF solids in the scrubbing zone so that the mixture of the scrubbing solvent composition 201 and the SCMF stream 101 produces a non-settling mixture in a fully stirred tank. Relative to the total combined weight of logistics 101 and 201, the concentration of SCMF in the scrubbing zone can be 0.1 wt % to 10 wt %, 0.1 wt % to 8 wt %, 0.1 wt % to 6 wt %, 0.1 wt % to 4 wt %, 0.1 wt % to 3 wt % and 0.1 wt % to 2 wt %.

[0222] The functions of washing and dewatering solids present in washing zone 200 have been described previously and apply here as well.

[0223] The two functions of washing and dehydrating can be performed in the same unit operation, or can be performed in separate unit operations in both batch and continuous equipment. Examples of equipment suitable for batch washing and continuous washing have been described previously and are suitable for use herein.

[0224] The washed SCMF solids stream 203 and the treated water stream 103 are conveyed to a mixing zone 300, wherein the substantially dewatered solids in stream 203 are re-slurried to form a SCMF stream 301. Any equipment known in the art suitable for mixing solids with water and maintaining the resulting cut multi-component fiber suspension in a continuous phase can be used in the fiber slurry zone 300. Suitable equipment for the mixing zone 300 includes a batch mixing vessel or a continuous mixing vessel. The mixing zone 300 may include a batch or continuous mixing device operating in a continuous or batch mode. Suitable equipment for the fiber slurry zone 300 includes, but is not limited to, a hydraulic pulper, a continuous stirred tank reactor, a tank with stirring operating in a batch mode.

[0225] There is no limit on the residence time. Agitation in the tank must be sufficient to produce a substantially uniform slurry that can be pumped. The weight percent of cut multicomponent fibers in SCMF slurry 301 can be 10 weight percent to 0.5 weight percent, 8 weight percent to 0.5 weight percent, 5 weight percent to 0.5 weight percent, or 3 weight percent to 0.5 weight percent.

[0226] The temperature of SCMF 301 may be 5° C. to 45° C., 10° C. to 35° C., or 10° C. to 25° C. In an embodiment, mixing slurry zone 300 comprises a tank having sufficient agitation to produce a suspension of cut multicomponent fibers in a continuous aqueous phase.

[0227] The SCMF slurry 301 may then be conveyed to a fiber opening zone 400. One function of the fiber opening zone 400 is to separate the water-dispersible polymer from the SCMF such that at least a portion of the water-indispersible polymer is separated from the SCMF and becomes suspended in the opened SCMF slurry 401. In embodiments, 50 wt% to 100 wt% of the water-indispersible polymer contained in the SCMF slurry 301 becomes suspended in the opened SCMF slurry 401 as water-indispersible polymer and is no longer part of the SCMF. In embodiments, 75 wt% to 100 wt%, 90 wt% to 100 wt%, or 95 wt% to 100 wt% of the water-indispersible polymer contained in the SCMF stream 301 becomes suspended in the opened SCMF slurry 401 as water-indispersible polymer that is no longer part of the cut multicomponent fibers.

[0228] The residence time, temperature, and shear force in the fiber opening zone 400 also affect the degree of separation of the water-dispersible sulfopolyester from the SCMF. The conditions that affect the opening process in the fiber opening zone 400 include residence time, slurry temperature, and shear force, wherein the range of water temperature, residence time, and amount of shear force applied in the fiber opening zone 400 depends on the need to separate the water-dispersible sulfopolyester from the starting multicomponent fibers to an extent sufficient to cause the water-non-dispersible polymer microfibers to become separated and suspended in the continuous aqueous phase of the opened microfiber slurry 401.

[0229] The temperature of the SCMF opening zone 400 can be 61° C. to 140° C., 65° C. to 135° C., 70° C. to 130° C., 75° C. to 125° C., 80° C. to 120° C., 80° C. to 115° C., 80° C. to 110° C., 80° C. to 105° C., 80° C. to 100° C., or 80° C. to 90° C. The residence time in the fiber opening zone 400 can be 10 seconds to 10 minutes, 20 seconds to 8 minutes, 20 seconds to 5 minutes, 20 seconds to 4 minutes, 20 seconds to 3 minutes, 20 seconds to 2 minutes, or 20 seconds to 1 minute.

[0230] Adequate mixing is maintained in the SCMF opening zone 400 to maintain suspension of the cut water non-dispersible polymer so that settling is minimized. In an embodiment, the mass per unit time of the cut water non-dispersible fibers that settle in the SCMF opening zone 400 is less than 5% of the mass per unit time of the cut water non-dispersible polymer microfibers entering the zone 400, less than 3% of the mass per unit time of the cut water non-dispersible polymer fibers entering the zone 400, or less than 1% of the mass per unit time of the cut water non-dispersible polymer fibers entering the fiber opening zone 400.

[0231] Opening the SCMF in the opening zone 400 can be completed in any equipment that allows an acceptable range of residence time, temperature and mixing. Examples of suitable equipment include, but are not limited to, stirred batch tanks, continuous stirred tank reactors, and pipelines with sufficient flow to minimize solid sedimentation from the slurry. An example of a unit operation for completing fiber opening in the fiber opening zone 400 is a plug flow reactor, in which the heated multi-component fiber slurry 301 is transported to a plug flow device in the zone 400, typically an annular pipe or conduit. The residence time of the material in the plug flow device is calculated by dividing the filling volume in the device by the volume flow rate in the device. The speed of the material in the device is defined by the volume flow rate of the liquid through the device divided by the cross-sectional area of ​​the flow channel.

[0232] In an embodiment, the fiber opening area 400 may include a pipe or conduit, wherein the material flow velocity in the pipe may be 0.1 ft / sec to 20 ft / sec, 0.2 ft / sec to 10 ft / sec, or 0.5 ft / sec to 5 ft / sec. The Reynolds number (Re) may be used to describe the turbulence or motion of a fluid eddy flow that is irregular in both direction and time. As described above, it will not be repeated here.

[0233] SCMF opening zone 400 can be realized in a pipe or conduit containing a mixing device inserted into the pipe or conduit. The device can include an in-line mixing device. The in-line mixing device can be a static mixer without moving parts. In an embodiment, the in-line mixing device includes moving parts. In a non-limiting manner, such elements are mechanical devices, and their purpose is to apply more mixing energy to the heated multi-component fiber slurry 301 than that obtained by flowing through the pipe. The device can be inserted at the beginning of a pipe section, the end of a pipe section, or any position in the pipe flow path as a fiber opening zone.

[0234] The opened SCMF slurry stream 401 comprising water non-dispersible cut polymer fibers, water and water dispersible sulfopolyester may be conveyed to a first solid-liquid separation zone 500 to produce a microfiber product stream 503 comprising microfibers and a first mother liquor stream 501. In embodiments, the first mother liquor stream 501 comprises an aqueous dispersion containing a water dispersible sulfopolyester.

[0235] The weight percent of solids in the opened microfiber slurry 401 may be 0.1 weight percent to 20 weight percent, 0.3 weight percent to 10 weight percent, 0.3 weight percent to 5 weight percent, or 0.3 weight percent to 2.5 weight percent.

[0236] The weight percent solids in the microfiber product stream 503 can be from 10 weight percent to 65 weight percent, from 15 weight percent to 50 weight percent, from 25 weight percent to 45 weight percent, or from 30 weight percent to 40 weight percent.

[0237] Separation of the microfiber product stream 503 from the opened microfiber slurry 401 can be achieved by any method known in the art. In an embodiment, a wash stream 103 comprising water is conveyed to the first solid-liquid separation zone 500. The wash stream 103 can be used to wash the microfiber product stream in the first solid-liquid separation zone 500 and / or the filter cloth medium in the first solid-liquid separation zone 500 to produce a wash liquid stream 502. Before entering the first solid-liquid separation zone 500, a portion of up to 100% by weight of the wash liquid stream 502 can be combined with the opened microfiber slurry 401. A portion of up to 100% by weight of the wash liquid stream 502 can be conveyed to the second solid-liquid separation zone 600. The wash liquid stream 502 can contain microfibers. In an embodiment, the number of grams of microfiber material passing through the filter medium having an opening up to 2000 microns in the first solid-liquid separation zone 500 is 1-2 grams / (cm 2 In an embodiment, the filter openings in the filter medium in the first solid-liquid separation region 500 may be 43 μm to 3000 μm, 100 μm to 2000 μm, or 500 μm to 2000 μm.

[0238] Separation of the microfiber product stream from the opened microfiber slurry in the first solid-liquid separation zone 500 may be accomplished by a single or multiple solid-liquid separation devices. The separation in the first solid-liquid separation zone 500 may be accomplished by one or more solid-liquid separation devices operating in intermittent and / or continuous modes. Suitable solid-liquid separation devices in the first solid-liquid separation zone 500 may include, but are not limited to, at least one of the following: a perforated basket centrifuge, a continuous vacuum belt filter, an intermittent vacuum suction filter, an intermittent perforated settling tank, a double-net dewatering device, a continuous horizontal belt filter with a compression zone, a non-vibrating inclined screen device with a wedge-shaped mesh filter medium, a continuous vacuum drum filter, a dewatering conveyor belt, and the like.

[0239] In an embodiment, the first SLS zone 500 comprises a twin-wire dewatering device, wherein the opened SCMF slurry 401 is conveyed to a conical gap between a pair of traveling filter cloths traveling in the same direction. In the first zone of the twin-wire dewatering device, water is drained from the opened microfiber slurry 401 due to gravity and the very narrow gap between the two moving filter cloths. In the downstream zone of the twin-wire dewatering device, the two filter cloths and the microfibrous mass between the two filter cloths are compressed one or more times to mechanically reduce the moisture in the microfibrous mass. In an embodiment, mechanical dewatering is accomplished by passing the two filter cloths and the contained microfibrous mass through at least one set of rollers that apply a compressive force to the two filter cloths and the microfibrous mass between them. In an embodiment, mechanical dewatering is accomplished by passing the two filter cloths and the microfibrous mass between them between at least one set of pressure rollers.

[0240] In embodiments, the force applied by the mechanical dewatering of each set of pressure rollers may be 25-300 pounds / (linear inch of filter media width), 50-200 pounds / (linear inch of filter media width), or 70-125 pounds / (linear inch of filter media width). A microfiber product stream 503 is discharged from the twin-wire dewatering device as the two filter cloths separate and separate in the solids discharge area of ​​the device. The thickness of the discharged microfibrous material may be 0.2 inches to 1.5 inches, 0.3 inches to 1.25 inches, or 0.4 inches to 1 inch. In embodiments, a wash stream comprising water is continuously applied to the filter media. In embodiments, a wash stream comprising water is periodically applied to the filter media.

[0241] In an embodiment, the first SLS zone 500 comprises a belt filter apparatus that includes a gravity drainage zone and a pressure dewatering zone. The opened SCMF slurry 401 is conveyed to a conical gap between a pair of moving filter cloths traveling in the same direction, passing first through the gravity drainage zone, and then through a pressure dewatering zone or pressing zone comprising a complex arrangement of rollers. As the belt feeds through the rollers, water is squeezed out of the solids. When the belt passes the last pair of rollers in the process, the filter cloths separate and the solids leave the belt filter apparatus.

[0242] In embodiments, at least a portion of the water contained in first mother liquor stream 501, which comprises an aqueous dispersion of sulfopolyester, may be recovered and recycled. First mother liquor stream 501 may be recycled to first SLS zone 500. Depending on the efficiency of the first liquid separation zone in removing water non-dispersible microfibers, first mother liquor stream 501 may be recycled to SCMF slurry zone 300, fiber opening zone 400, or heat exchanger zone 800 before being conveyed to zone 400. First mother liquor stream 501 may contain a small amount of solids comprising water non-dispersible polymer microfibers due to penetration and washing, such as machine washing. In embodiments, the grams of water non-dispersible polymer microfiber material passing through a filter medium having openings up to 2000 microns in the first solid-liquid separation zone is 1-2 grams / (cm 2 It is desirable to minimize water non-dispersible polymer microfibrous solids in the first mother liquor stream 501 prior to conveying the stream 501 to the first concentrating zone 700 and the heat exchange zone 800 where the water non-dispersible polymer microfibrous solids can collect and accumulate in the zone and negatively impact its function.

[0243] The second SLS zone 600 can be used to remove at least a portion of the water non-dispersible polymer microfiber solids present in the first mother liquor stream 501 to produce a second wet cake stream 602 comprising water non-dispersible microfibers and a second mother liquor stream 601 comprising an aqueous dispersion of water-dispersible sulfopolyester.

[0244] In embodiments, the second mother liquor stream 601 may be sent to the first concentrating zone 700 and or the heat exchanger zone 800, wherein the weight percent of the second mother liquor stream 601 sent to the first concentrating zone 700 may be from 0% to 100% with the balance of the stream sent to the heat exchanger zone 800. The second mother liquor stream 601 may be recycled to the fiber slurry zone 200, the fiber opening zone 400, or the heat exchanger zone 800 before being sent to zones 200 and / or 400. The amount of water-dispersible sulfopolyester in the second mother liquor stream sent to the fiber opening zone 400 may be from 0.01% to 7% by weight, or from 0.1% to 7% by weight, from 0.2% to 5% by weight, or from 0.3% to 3% by weight based on the weight percent of the second mother liquor stream.

[0245] Any portion of the second mother liquor 601 sent to the first concentration zone is subjected to a separation process to produce a first recovered water stream 703 and a first SFP concentrate stream 702 enriched in water-dispersible sulfopolyester, wherein the weight percent of water-dispersible sulfopolyester in the first SFP concentrate stream 702 relative to the total weight of the concentrated sulfopolyester dispersion can be 1 wt % to 40 wt %, 1 wt % to 30 wt %, 1 wt % to 25 wt %, 1 wt % to 20 wt %, 1 wt % to 15 wt %, 5 wt % to 30 wt %, 10 wt % to 30 wt %, 15 wt % to 30 wt %, 20 wt % to 30 wt %, or 25 wt % to 30 wt %. The first SFP concentrate stream 702 comprises a recovery rate of sulfopolyester in the composite material of 50% to 99.9%, 75% to 99.9%, 65%, 75% to 99%, 80% to 98%, 85% to 97%, 90% to 96%, or 91% to 95%.

[0246] The first recovered water stream 703 may be recycled to the fiber opening zone 400 or the heat exchanger zone 800 before being delivered to zone 400. The amount of water-dispersible sulfopolyester in the second mother liquor stream delivered to the fiber opening zone 400 may be from 0.01 wt % to 7 wt %, or from 0.1 wt % to 7 wt %, from 0.2 wt % to 5 wt %, or from 0.3 wt % to 3 wt %, based on the wt % of the second mother liquor stream.

[0247] As previously described, water may be removed from the second mother liquor stream 601 in the first concentration zone 700 by any method known in the art to produce the first SFP concentrate stream 702. Removal of water by evaporation processes or membrane technology as previously described may be applicable hereto. In addition, membrane filtration for sulfopolyester concentration accomplished in either a batch or continuous mode as previously discussed is also applicable hereto.

[0248] In an embodiment, the first polymer concentrate stream 702 may be conveyed to a second concentrating zone 900 to produce a molten polymer stream 903 comprising a water-dispersible sulfopolyester wherein the weight percent of polymer is from 95% to 100%, and to produce a vapor stream 902 comprising water. In an embodiment, 903 comprises a water-dispersible sulfopolyester. Suitable equipment for use in the second concentrating zone 900 includes any equipment known in the art capable of feeding an aqueous dispersion of a water-dispersible polymer and producing a 95% to 100% water-dispersible polymer stream 903. The embodiment includes feeding an aqueous dispersion of a water-dispersible sulfopolyester polymer to the second concentrating zone 902. The temperature of the feed stream is typically less than 100°C.

[0249] In embodiments, the second concentrating zone 900 comprises at least one apparatus characterized by a jacketed shell containing a rotating conveying screw, wherein the conveying screw is heated with a heat transfer fluid or steam, and includes both conveying and high shear mixing elements. The jacket or shell is vented to allow vapor to escape. The shell jacket may be zoned to allow different temperature set points along the length of the apparatus. During continuous operation, the first polymer concentrate stream 702 comprises an aqueous dispersion of a water-dispersible sulfopolyester and is continuously fed to the second concentrating zone 900. Within the apparatus, during steady state, the material exists in at least three distinct and different forms, as previously described and applicable herein.

[0250] In embodiments, vapor produced in second concentrating zone 900 may be condensed and sent to heat exchanger zone 800, discarded, and / or sent to wash stream 103. In embodiments, condensed vapor stream 902 comprising water vapor may be sent to heat exchanger zone 800 to provide at least a portion of the energy required to produce the desired temperature for stream 801. Molten polymer stream 903 comprising the sulfopolyester-containing water-dispersible polymer in the molten phase may be cooled to a solid and cut into pellets by any method known in the art.

[0251] Impurities may enter the process and concentrate in the recovered and recycled water. One or more purge streams (603 and 701) may be used to control the impurity concentrations in the second mother liquor 601 and the first recovered water stream 701 to acceptable levels. In embodiments, a portion of the second mother liquor stream 601 may be separated and purged from the process. In embodiments, a portion of the first recovered water stream 701 may be separated and purged from the process.

[0252] The recovered sulfopolyester can be reused in the manufacturing process. Exemplary uses of the recovered sulfopolyester include forming new articles or products such as sizing agents, dust suppressants, binders for nonwovens, ink additives, nonwovens, multicomponent fibers, films, apparel articles, personal care products such as wipes, feminine hygiene products, diapers, adult incontinence briefs, disposable medical supplies, protective fabrics and layers, geotextiles, industrial wipes, and filtration media. Adhesives, cosmetics and personal care, foil lining coatings, graphic arts, concrete sealants, wood coatings, automotive plastics, film formers / film modifiers, paper coatings, packaging materials, carpet stain repellents, mineral flotation foaming, and general coatings.

[0253] Sizing agent

[0254] In embodiments, the recycled sulfopolyesters described herein may be used as a sizing agent in a sizing composition. The recycled sulfopolyester may be in the form of a recycled sulfopolyester dispersion. The recycled sulfopolyester dispersion may be used as a sizing agent to size one or more of fibers, filaments, fiber products (e.g., textile yarns, twine, tire cords, yarns on warp beams, etc.), paper materials, fabrics (e.g., decorative fabrics, home furnishings, etc.), nonwoven materials (e.g., wet-laid nonwovens), etc. As used herein, "sizing" refers to the process of applying a protective coating or film.

[0255] A sizing composition comprising a recovered sulfopolyester dispersion can be used to treat warp yarns. When the textile material is used to make a textile material in the form of a multifilament yarn, it is desirable to treat the warp yarns prior to the weaving process with a sizing composition that adheres to and binds several filaments together. This treatment strengthens the filaments and makes them more resistant to wear during subsequent weaving operations. It is particularly important that the sizing composition imparts wear resistance to the yarn during the weaving process, as wear tends to cut the yarn and produce broken ends, which of course reduces the quality of the final woven product.

[0256] In embodiments, for greater efficiency, it is necessary to substantially scrub or remove the textile size from the woven fabric so that it does not interfere with subsequent fabric finishing and dyeing operations. In practical terms, this means that the removable sizing composition must be water-diffusible (i.e., either water-soluble or water-dispersible). The recovered sulfopolyester is water-dispersible.

[0257] The sizing compositions described herein are particularly useful for sizing polyester yarns, which are one of the most difficult to size of all textile yarns. The sizing compositions described herein allow low-twist or zero-twist polyester fibers to be woven with substantially no defects. Tg is important for the performance of the sulfopolyester as a sizing. In embodiments, the Tg of the recovered sulfopolyester is from 25°C to 50°C or from 30°C to 40°C. The addition of a plasticizing component can be used to lower the Tg of the sulfopolyester, and polyethylene glycol (PEG) is a preferred choice for this purpose, although other additives can be used.

[0258] In embodiments, the sizing composition is not removable, such as in the case of sized tire cord (eg, rayon, nylon, or polyester tire cord) and twine.

[0259] The recycled sulfopolyester dispersion can modify one or more of the abrasion resistance, creasibility, finish, printability, smoothness, or surface adhesion strength of a textile. In addition, the recycled sulfopolyester dispersion can reduce the surface porosity or fuzzing of the textile. In addition, the recycled sulfopolyester dispersion can modify the absorption of the textile by reducing the absorption of the ink when the ink is applied to the textile. Further, sizing using the recycled sulfopolyester dispersion can produce a smoother and / or water-resistant paper surface and / or improve the surface strength and printability of the paper.

[0260] The sizing compositions described herein may also include a recycled sulfopolyester dispersion, which may also include one or more of polyethylene glycol, a plasticizer, one or more dyes, one or more pigments, talc, titanium dioxide, or one or more stabilizers.

[0261] In embodiments, the recycled sulfopolyester dispersion is present in the sizing composition at a weight % of 0.1% to 40%, 0.5% to 35%, 1% to 30%, 2% to 25%, 3% to 20%, 4% to 15%, or 5% to 10%, relative to the total weight of the sizing composition.

[0262] The present disclosure also describes a method of using the recovered sulfopolyester dispersion in the manufacture of a sizing composition. The method includes obtaining a recovered sulfopolyester dispersion and combining the recovered sulfopolyester dispersion with other components, such as at least water. Additional components, such as water, polyethylene glycol, a plasticizer, one or more dyes, one or more pigments, talc, titanium dioxide, one or more stabilizers, one or more thickeners, etc., as described above, can be combined with the recovered sulfopolyester dispersion and water.

[0263] In addition, the present disclosure describes methods of using the recycled sulfopolyester dispersion as a sizing agent in the manufacture of textile materials and other materials and articles. A sizing composition containing the recycled sulfopolyester dispersion can be applied to the material and / or article. In embodiments, the recycled sulfopolyester dispersion can be used as a sizing agent in the manufacture of yarn, paper material, fabric, or nonwoven material on a warp beam.

[0264] Dust suppressants

[0265] Dust, especially from industrial sources, is a major contributor to air pollution. Everyone knows that dust generated during coal mining operations is considered the leading cause of pneumoconiosis, more commonly known as black lung. Dust explosions are a serious hazard because dust is confined to small air spaces during coal mining operations. In addition, large amounts of coal dust are generated during transportation, handling, and storage. Open-air operations, leaks and spills, storage and disposal, and poor housekeeping are also sources of common industrial dust.

[0266] Dust suppression refers to the prevention and / or reduction of the suspension of fine particulate solid matter in a gas (usually air). The fine particulate solid matter may already be present or may be generated by various mechanical operations such as grinding, milling, cutting, pounding, blasting, etc. There is a need to develop a method for suppressing dust.

[0267] In an example, the recycled sulfopolyesters described herein can be used as dust suppressants in dust suppressant compositions. The recycled sulfopolyesters can be in the form of recycled sulfopolyester dispersions. The recycled sulfopolyester dispersions described herein provide a method by which dust can be suppressed. The recycled sulfopolyester dispersions can prevent or reduce the suspension of dust in the air.

[0268] In embodiments, dust suppressant compositions containing the recycled sulfopolyester dispersion may be applied to roads, airports, helipads, and the like to control dust. In embodiments, the recycled polyester penetrates and aggregates fine dust particles to reduce airborne dust and runoff by strengthening the soil surface. The dust suppressant composition may be used for erosion control, stabilizing roads, and the like. Use of a dust suppressant composition including the recycled polyester dispersion reduces or eliminates the need to apply water to the surface to which it is applied for ongoing dust control. Reducing dust may reduce respiratory illnesses, equipment failures, and lack of visibility.

[0269] In embodiments, dust suppressant compositions containing the recycled sulfopolyester dispersion may be applied to other materials including, but not limited to, coal, rock, ore, taconite, sulfur, copper, limestone, gypsum, fly ash, cement, bauxite, ash, sinter, coke, mineral concentrates, or fertilizers.

[0270] In embodiments, dust suppressant compositions comprising the recycled sulfopolyester dispersion may include additional water (in addition to the water that is part of the dispersion) and one or more other components including, but not limited to, one or more surfactants, acrylic polymers (e.g., vinyl acrylic polymers), polyvinyl acetate polymers, potassium hydroxide, sodium hydroxide, potassium methyl silicate, sodium methyl silicate, esters, glycerin, or combinations thereof. Examples of surfactants include sodium dodecylbenzene sulfonate, ethoxylated alcohols, and sodium lauryl sulfate.

[0271] In embodiments, the amount of recycled sulfopolyester present in the dust suppression composition is from 0.1 wt % to 40 wt %, from 0.5 wt % to 40 wt %, from 1 wt % to 40 wt %, from 2 wt % to 40 wt %, from 5 wt % to 40 wt %, from 10 wt % to 40 wt %, from 15 wt % to 40 wt %, or from 20 wt % to 40 wt %, relative to the total weight of the dust suppressant.

[0272] In an embodiment, the present disclosure describes a method of using a recycled sulfopolyester dispersion in the manufacture of a dust suppressant composition. The method includes obtaining a recycled sulfopolyester dispersion and combining the recycled sulfopolyester dispersion with one or more additional components as described above, such as one or more surfactants, acrylic polymers (vinyl acrylic polymers), polyvinyl acetate polymers, potassium hydroxide, sodium hydroxide, potassium methyl silicate, sodium methyl silicate, esters, glycerin, and the like.

[0273] In embodiments, the present disclosure describes methods of suppressing dust on roads using a dust suppressant composition containing recycled sulfopolyesters. The dust suppressant composition as described above can be sprayed onto the road surface and allowed to dry. This causes the soil particles to form a "crust," thereby reducing dust in the air.

[0274] In embodiments, the present disclosure describes the use of dust suppressant compositions containing recycled sulfopolyesters to suppress dust from coal, rock, ore, taconite, sulfur, copper, limestone, gypsum, fly ash, cement, bauxite, ash, sinter, coke, mineral concentrate, or fertilizer.

[0275] Adhesives

[0276] Nonwoven fabrics are typically made by putting fibers together in the form of a sheet or web and then bonding them mechanically (with an adhesive) or thermally (by applying a bonding composition (in the form of a powder, paste, or polymer melt) and melting the bonding composition onto the web by increasing the temperature). The fiber web can be in the form of a wet-laid process or a dry-laid process. In the wet-laid process, the fibers that make up the nonwoven fabric are dispersed in water and formed into a sheet or web. After most of the water is removed, the fibers are bonded by applying some type of adhesive (usually latex). In the dry-laid process, dry fibers are subjected to a carding operation that forms the fibers into a web, and then an adhesive is applied to the web to hold the fibers together. The thermal bonding process is a process that uses adhesive fibers to form a thermally bonded fiber structure.

[0277] A bonding composition comprising an adhesive is applied to a web of fibers and the fibers are mechanically held together to form a bonded nonwoven. As used herein, a "nonwoven" is a sheet or web structure made of fibers or filaments bonded together by chemical, mechanical, thermal or solvent treatments, without weaving or knitting. Nonwovens can provide specific functions, such as ink absorption, liquid resistance, resilience, stretchability, softness, strength, flame retardancy, washability, cushioning, thermal insulation, sound insulation, filterability, use as a bacterial barrier, and sterility.

[0278] Meltblown nonwovens can be produced by extruding molten polymer fibers through a textile web or die to form elongated fibers, which are stretched and cooled by sending hot air over them as they fall from the die. The resulting web is collected into rolls and subsequently converted into finished products.

[0279] In embodiments, the sulfopolyester of recovery described herein can be used as an adhesive in the manufacture of nonwoven materials. The recovered sulfopolyester can be in the form of a recovered sulfopolyester dispersion, wherein the recovered sulfopolyester dispersion comprises at least the recovered sulfopolyester and water. The recovered sulfopolyester dispersion can be combined with one or more adhesives in an adhesive composition. Relative to the gross weight of the adhesive composition, the amount of the recovered sulfopolyester is 0.1 wt % to 40 wt %, 0.5 wt % to 40 wt %, 1 wt % to 40 wt %, 2 wt % to 40 wt %, 5 wt % to 40 wt %, 10 wt % to 40 wt %, 15 wt % to 40 wt %, or 20 wt % to 40 wt %.

[0280] In embodiments, the recycled sulfopolyester dispersion adhesive composition may modify at least one of the dry tensile strength, wet tensile strength, tear force, or burst resistance of the nonwoven material.

[0281] In an embodiment, the bonding composition may include a recycled sulfopolyester dispersion and one or more additives. The one or more additives may include, but are not limited to, thermoplastic condensation polymer fibers.

[0282] In an embodiment, the present disclosure describes a method of using a recycled sulfopolyester dispersion in the manufacture of an adhesive composition. The method includes obtaining a recycled sulfopolyester dispersion and combining the recycled sulfopolyester dispersion with an additive including, but not limited to, a thermoplastic condensation polymer fiber.

[0283] In an embodiment, the present disclosure describes a method for using a recycled sulfopolyester dispersion as an adhesive in the manufacture of a nonwoven composition. The adhesive composition containing the recycled sulfopolyester dispersion can be applied to a nonwoven material to form a nonwoven composition. In an embodiment, the nonwoven material includes at least one of the following: spun-bounded nonwoven material, heat-sealed nonwoven material, spunlace nonwoven material, needle-punched nonwoven material, melt-blown nonwoven material, stitch-bonded nonwoven material, dry-laid papermaking nonwoven material, wet-laid nonwoven material, filter media, battery pack separator, personal hygiene products, sanitary napkins, tampons, diapers, disposable wet wipes, flexible packaging, geotextiles, building and construction materials, surgical and medical materials, security paper, cardboard, recycled cardboard, synthetic leather and suede, automotive roof lining, personal protective clothing, acoustic media, concrete reinforcement, flexible preforms of compression-molded composite materials, electrical materials, catalytic support films, thermal insulation, labels, food packaging materials, or printing or publishing paper.

[0284] In embodiments, nonwoven articles include a plurality of thermoplastic polycondensate fibers and a bonding composition comprising a sulfopolyester dispersion of recovery. Thermoplastic polycondensate fibers may include polyester and / or polyamide, and relative to the gross weight of the nonwoven composition, constitute 1 wt % to 10 wt %, 5 wt % to 20 wt %, 10 wt % to 30 wt %, 20 wt % to 40 wt %, 30 wt % to 50 wt % or 60 wt % of the total fiber content of the nonwoven article, and the sulfopolyester of recovery constitutes at least 0.1 wt % of the nonwoven article and is no more than 40 wt %. Relative to the gross weight of the nonwoven composition, the bonding composition may constitute 0.1 wt % to 10 wt %, 0.1 wt % to 7 wt %, 0.1 wt % to 5 wt % or 0.1 wt % to 3 wt %. The nonwoven article further includes a plurality of synthetic microfibers less than 25 millimeters in length and less than 5 microns in minimum transverse dimension, wherein the synthetic microfibers constitute at least 1 wt % of the nonwoven article.

[0285] In embodiments, the bonding composition may include a recycled sulfopolyester dispersion described herein and another sulfopolyester.

[0286] In an embodiment, a bonded nonwoven article can be produced using a recycled sulfopolyester dispersion. The first step of the method involves a) producing a multicomponent fiber comprising at least one water-dispersible recycled sulfopolyester and one or more water-indispersible polymers that are immiscible with the recycled sulfopolyester. The as-spun denier of the multicomponent fiber can be less than 15 dpf. The next step b) involves cutting the multicomponent fiber into cut multicomponent fibers having a length of less than 25 mm. Step c) involves contacting the cut multicomponent fibers with water to remove the recycled sulfopolyester, thereby forming a wet lap comprising cut water-indispersible fibers formed from a thermoplastic condensation polymer. Step d) involves transferring the wet lap to a wet-laid nonwoven area to produce an unbonded nonwoven article. The final step e) involves applying a binder dispersion comprising at least one recycled sulfopolyester to the nonwoven article.

[0287] In an embodiment, a nonwoven article can be produced using the recycled sulfopolyester dispersion by: (1) spinning the sulfopolyester and a water non-dispersible synthetic polymer into multicomponent fibers, (2) cutting the multicomponent fibers into a length less than 25, 12, 10, or 2 mm, but greater than 0.1, 0.25, or 0.5 mm to produce cut multicomponent fibers; (3) contacting the cut multicomponent fibers with water to remove the sulfopolyester, thereby forming a wet roll of binder microfibers comprising the water non-dispersible synthetic polymer; (4) subjecting the plurality of fibers and the binder microfibers to a wet-laid nonwoven process to produce a wet-laid nonwoven web; wherein the water non-dispersible microfibers have a fineness of less than 0.5 d / f; and wherein the melting temperature of the binder microfibers is lower than the melting temperature of the fibers; and (5) removing water from the wet-laid nonwoven web; and (6) thermally bonding the wet-laid nonwoven web after step (5), wherein the thermal bonding is performed at a temperature such that the surfaces of the binder microfibers at least partially melt without causing the fibers to melt, thereby bonding the binder microfibers to the fabric to produce a paper or nonwoven article. In one embodiment of the present invention, at least 5%, 10%, 15%, 20%, 30%, 40%, or 50% by weight and / or no more than 90%, 75%, or 60% by weight of the nonwoven web comprises binder microfibers.

[0288] Ink Additives

[0289] In embodiments, the recovered sulfopolyesters described herein can be used in ink compositions. The recovered sulfopolyesters can be in the form of a recovered sulfopolyester dispersion and can aid in the dispersion of a pigment or colorant in water. Additionally, the recovered sulfopolyester dispersion can reduce the drying time of the ink. Furthermore, the recovered sulfopolyester dispersion can reduce or eliminate the need for a surfactant in the ink composition.

[0290] The term "ink" or "ink composition" is used herein in its broad sense, such as to include its use in: all forms of coatings such as lettering, patterns and coatings without designs, whether or not such coatings contain colorants such as pigments; and including finished inks, overprints and primers. The present disclosure is not limited to any type of colorant and can accommodate any pigment or disperse dye that can be dispersed, ground, mixed, blended or dissolved in any manner in a polyester, water or waterborne polymer system.

[0291] In embodiments, the recycled sulfopolyester dispersion imparts improved water resistance and anti-blocking properties to printing inks for certain substrates, such as certain metals such as aluminum foil and plastics such as poly(ethylene terephthalate). Other substrates may include metal foils, newsprint, bleached and unbleached kraft paper, clay-coated paper, glass, calendared paper, stainless steel paper, paperboard, and films or other substrates of polyester, polycarbonate, cellulose ester, regenerated cellulose, poly(vinylidene chloride), polyamide, polypropylene, polyethylene, polystyrene, and the like. The ink compositions described herein may be used in any typical ink application, such as flexographic, gravure, letterpress, inkjet, or screen printing applications. The pH of the ink compositions described herein is typically 8.2 or less; in embodiments, the pH of the ink compositions described herein is from 5 to 8. If the pH is above 8.2, there is a risk of hydrolysis of one or more polymers, which may, in some cases, lead to gelation of the system.

[0292] In embodiments, the recycled polyester dispersion described herein may be combined with a colorant and water to form an ink composition. The amount of recycled sulfopolyester present in the ink composition is 1 wt % to 80 wt %, 2 wt % to 75 wt %, 3 wt % to 75 wt %, 5 wt % to 70 wt %, 7 wt % to 65 wt %, 10 wt % to 60 wt %, 15 wt % to 55 wt %, 20 wt % to 50 wt %, relative to the total weight of the ink composition.

[0293] The amount of water present in the ink composition is 15 wt % to 95 wt %, 25 wt % to 90 wt %, or 35 wt % to 90 wt % relative to the total ink composition.

[0294] In embodiments, the ink composition further includes one or more colorants. The amount of the colorant present in the ink composition is 0.1% by weight to 45% by weight, 0.5% by weight to 35% by weight, or 1.0% to 30% or 2% by weight to 15% by weight. In embodiments where the ink composition is a finished ink, there is usually at least 0.5% by weight of the colorant. If the ink composition contains an organic pigment, this organic pigment is usually present in an amount of 17.5% by weight or less of the total composition. If the ink composition contains an inorganic pigment, this inorganic pigment is usually present in an amount of 50% by weight or less of the total composition.

[0295] In embodiments, the ink composition comprising the recycled sulfopolyester may include additional additives, including one or more of the following: one or more surfactants (e.g., sodium lauryl sulfate); one or more wetting agents; one or more defoaming agents or one or more dispersants. Additionally or alternatively, the ink composition may include one or more of the following: organic compounds; one or more salts; one or more resins; one or more water-soluble organic solvents; one or more water-miscible organic solvents; one or more acrylic polymers; one or more vinyl polymers; one or more emulsified, dispersed, powdered or micronized waxes; alcohols containing 1-10 carbon atoms such as ethanol, methanol, n-propanol or isopropanol; glycols such as ethylene glycol or propylene glycol; alcohol ethers such as propylene glycol monobutyl ether, ethylene glycol monobutyl ether or propylene glycol monomethyl ether; biocides; pH stabilizers; thickeners, etc.

[0296] The ink composition may optionally contain up to 15% by weight of the total composition or up to 3% by weight of one or more additional additives. In an embodiment, wax is present in the ink composition at 0% to 3.0% by weight; surfactant is present in the ink composition at 0% to 3.0% by weight; defoamer is present in the ink composition at 0% to 2.0% by weight; and alcohol is present in the ink composition at 0% to 10.0% by weight. Defoamer or defoamer may be present in an amount of 0.05% to 0.25% by weight or 0.1% to 0.25% by weight. Biocides are typically present in an amount of 0% to 1% by weight. Wax is particularly useful in certain ink compositions, especially overprinting, and such inks typically contain at least 0.01% by weight of one or more waxes.

[0297] In embodiments, the recovered sulfopolyester has an intrinsic viscosity (IV) of at least 0.1, and may be from 0.2 to 1.0, from 0.2 to 0.6, as determined according to the ASTM D2857-70 procedure.

[0298] In embodiments, the present disclosure describes methods of using a recovered sulfopolyester in the manufacture of an ink composition. The method includes obtaining a recovered sulfopolyester dispersion and combining the recovered sulfopolyester dispersion with other components, such as at least water. Additional additives as described above may be combined with the recovered sulfopolyester dispersion and water. In embodiments, the recovered sulfopolyester may be in resin form or may be a solution when mixed with other components.

[0299] In embodiments, to form an ink composition, a colorant is combined with a recycled sulfopolyester dispersion and water. For example, the colorant may be flushed into the recycled sulfopolyester dispersion. A shearing device may be used to disperse the colored recycled sulfopolyester dispersion in water.

[0300] Unless otherwise indicated, the definitions provided herein for a group or term apply to that group or term throughout this specification, either independently or as part of another group. In addition, it should be understood that any listing of any such examples or alternatives is merely illustrative and not restrictive, unless otherwise implied or explicitly understood or clarified.

[0301] The terms "a," "an," "the," and similar referents used in the context of describing the disclosed subject matter (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context.

[0302] Each embodiment disclosed herein may include, consist essentially of, or consist of the elements, steps, ingredients, or components specifically set forth therein. Therefore, the term "includes" or "comprising" should be interpreted as reciting: "includes, consists of, or consists essentially of". The transitional term "includes" or "comprising" means including, but not limited to, and allows for the inclusion of unspecified elements, steps, ingredients, or components, even in major amounts. The transitional phrase "consisting of" excludes any unspecified elements, steps, ingredients, or components. The transitional phrase "consisting essentially of" limits the scope of the embodiment to the specified elements, steps, ingredients, or components, as well as those that do not substantially affect the embodiment.

[0303] In addition, unless otherwise indicated, the numbers used in the specification and claims expressing the amounts of ingredients, components, reaction conditions, etc. should be understood as being modified by the term "about". Therefore, unless otherwise indicated, the numerical parameters specified in the specification and the appended claims are approximate values, which may vary depending on the desired properties sought to be obtained by the subject matter presented herein. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be interpreted in light of the number of reported significant figures and by applying ordinary rounding techniques. When further clarification is required, the term "about" has the meaning reasonably assigned to it by those skilled in the art when used in conjunction with a specified value or range, i.e., refers to a certain degree more or a certain degree less than the specified value or range, which is ±20% of the specified value; ±15% of the specified value; ±10% of the specified value; ±5% of the specified value; ±4% of the specified value; ±3% of the specified value; ±2% of the specified value; ±1% of the specified value; or any percentage from ±1% to 20% of the specified value.

[0304] The recording of numerical ranges herein is intended only to be used as a shorthand method for individually quoting each individual value falling within the range. Unless otherwise specified herein, each individual value is incorporated into the specification as if it were individually recorded herein. It should be understood that the description in the form of ranges is merely for convenience and brevity, and should not be interpreted as a hard limit to the scope of the present disclosure. Therefore, it should be considered that the description of the range specifically discloses all possible sub-ranges and individual values ​​within the range. For example, it should be considered that the description of a range such as 1 to 6 specifically discloses sub-ranges, such as 1 to 3, 1 to 4, 1 to 5, 2 to 4, 2 to 6, 3 to 6, etc., as well as individual numbers within the range, for example, 1, 2, 2.7, 3, 4, 5, 5.3 and 6. This applies regardless of the width of the range.

[0305] All methods described herein can be performed in any suitable order unless otherwise indicated herein or clearly contradicted by context.

[0306] The use of any and all examples or exemplary language (e.g., "such as") provided herein is intended merely to better explain the disclosed subject matter and does not constitute a limitation on the scope of the disclosed subject matter otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosed subject matter.

[0307] The groups of alternative elements or embodiments of the disclosed subject matter disclosed herein should not be construed as limiting. Each group member may be referred to and claimed individually or in any combination with other members of the group or other elements found herein.

[0308] Certain embodiments of the disclosed subject matter are described herein, including the best mode known to the inventor for performing the disclosed subject matter. Of course, after reading the above description, variations of the embodiments described will become apparent to those of ordinary skill in the art. The inventor expects that skilled technicians will adopt such variations as appropriate, and the inventor intends to practice the disclosed subject matter in a manner different from that specifically described herein. Therefore, where permitted by applicable law, the disclosed subject matter includes all modifications and equivalents to the subject matter recorded in the claims appended hereto. In addition, unless otherwise specified herein or otherwise clearly refuted by the context, any combination of the above elements in all possible variations thereof is covered by the disclosed subject matter.

[0309] The above-described subject matter is provided by way of illustration only and should not be construed as limiting. Various modifications and changes may be made to the subject matter described herein without following the illustrated and described example embodiments and applications, and without departing from the true spirit and scope of the present disclosure as set forth in the appended claims.

[0310] All publications, patents and patent applications cited in this specification are incorporated herein by reference in their entirety, just as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference. Although the foregoing has been described according to various embodiments, it will be appreciated by those skilled in the art that various modifications, substitutions, omissions and changes may be made without departing from the spirit thereof.

Claims

1. A pre-washed recycled sulfopolyester dispersion comprising a recycled sulfopolyester and a solvent composition; wherein the dispersion comprises from 0.01 wt % to 5 wt % impurities relative to the total weight of the recycled sulfopolyester dispersion, wherein the pre-washed recycled sulfopolyester dispersion is obtained from a composite material, wherein the pre-washing removes additional undesirable impurities from the composite material, and the pre-washing washes the composite material prior to opening and / or mixing with treated water, The pre-washed recycled sulfopolyester exhibits an average molecular weight of at least 50% to 99% of the molecular weight of the sulfopolyester present in the composite material, and wherein the dispersion has at least an 80% or more reduced impurity concentration compared to a recycled sulfopolyester dispersion that has not been pre-washed.

2. The dispersion of claim 1, wherein the dispersion comprises one or more of the following properties: The average dispersed particle size is 10-500nm; Particle size distribution is 1-1000nm; Solution viscosity is 50-1000cp; Molecular weight of 2-20 kDa; or The multivalent ion content is less than 60 ppm by weight.

3. The dispersion of claim 1, wherein the recovered sulfopolyester has a glass transition temperature (Tg) of 25°C to 120°C.

4. The dispersion of claim 1, wherein the recovered sulfopolyester comprises: residues of one or more dicarboxylic acids; 4-40 mole % of at least one sulfomonomer residue, based on the total repeating units, comprising two functional groups and one or more sulfonate groups attached to an aromatic or alicyclic ring, wherein the functional groups are hydroxyl, carboxyl, or a combination thereof; and One or more diol residues, based on the total diol residues, the one or more diol residues are 10-100 mol% and are of the structure H(OCH2CH2) n Poly(ethylene glycol) of OH, wherein n is an integer from 2 to 500; and 0-25 mole % of the residue of a branching monomer having 3 or more functional groups, based on the total repeating units, wherein the functional groups are hydroxyl, carboxyl, or a combination thereof.

5. The dispersion of claim 1 wherein the recovered sulfopolyester comprises a salt of a sulfoisophthalate moiety.

6. The dispersion of claim 5 wherein the salt of the sulfoisophthalate moiety is derived from sodium 5-sulfoisophthalate or an ester thereof.

7. The dispersion of claim 1 wherein the sulfopolyester is selected from: (1) A water-dispersible sulfopolyester comprising: (a) residues of one or more dicarboxylic acids; (b) at least 10 mole percent of residues of at least one sulfomonomer; and (c) residues of two or more diols, wherein the diols include 1,4-cyclohexanedimethanol and diethylene glycol, wherein the sulfopolyester exhibits a glass transition temperature of at least 57°C, wherein the sulfopolyester contains substantially equal molar proportions of acid moiety repeating units and hydroxyl moiety repeating units, wherein the acid moiety repeating units equal 100 mole percent and the hydroxyl moiety repeating units equal 100 mole percent, and wherein all of said mole percents are based on the sum of all of the acid and hydroxyl moiety repeating units, said sum equals 200 mole percent; (2) A water-dispersible sulfopolyester comprising: (a) the residue of isophthalic acid; (b) residues of terephthalic acid; (c) the residue of at least one sulfomonomer; (d) residues of 1,4-cyclohexanedimethanol; and (e) a residue of diethylene glycol, wherein the sulfopolyester exhibits a glass transition temperature of at least 57°C, wherein the sulfopolyester contains substantially equal molar proportions of acid moiety repeating units and hydroxyl moiety repeating units, wherein the acid moiety repeating units equal 100 mole percent, the hydroxyl moiety repeating units equal 100 mole percent, and wherein all said mole percents are based on the sum of all acid and hydroxyl moiety repeating units, said sum equals 200 mole percent; (3) A sulfopolyester comprising: (a) residues of one or more dicarboxylic acids; (b) at least 10 mole percent of residues of at least one sulfomonomer; and (c) residues of two or more diols, wherein the diols include ethylene glycol and diethylene glycol, wherein the sulfopolyester exhibits a glass transition temperature of at least 58°C, wherein the sulfopolyester comprises a molar ratio of diethylene glycol to ethylene glycol of less than 0.65, wherein the sulfopolyester contains substantially equimolar ratios of acid moiety repeating units to hydroxyl moiety repeating units, and wherein the acid moiety repeating units are equal to 100 mole percent and the hydroxyl moiety repeating units are equal to 100 mole percent, wherein all said mole percents are based on the sum of all acid and hydroxyl moiety repeating units, said sum being equal to 200 mole percent; and (4) An amorphous sulfopolyester comprising: (a) the residue of isophthalic acid; (b) residues of terephthalic acid; (c) the residue of at least one sulfomonomer; (d) residues of ethylene glycol; and (e) a residue of diethylene glycol, wherein the amorphous sulfopolyester exhibits a glass transition temperature of at least 58°C, wherein the amorphous sulfopolyester comprises substantially equal molar proportions of acid moiety repeating units and hydroxyl moiety repeating units, wherein the acid moiety repeating units equal 100 mole percent, the hydroxyl moiety repeating units equal 100 mole percent, and wherein all said mole percents are based on the sum of all acid and hydroxyl moiety repeating units, said sum equals 200 mole percent; (5) A sulfopolyester comprising: (a) residues of one or more dicarboxylic acids; (b) at least 4 mole percent and less than 8.5 mole percent of residues of at least one sulfomonomer; and (c) residues of one or more diols, wherein the sulfopolyester comprises a ratio of carboxylate end groups to acid end groups of at least 0.6, wherein said sulfopolyester comprises substantially equimolar ratios of acid moiety repeating units to hydroxyl moiety repeating units, wherein the acid moiety repeating units equal 100 mole percent, the hydroxyl moiety repeating units equal 100 mole percent, and wherein all said mole percents are based on the sum of all acid and hydroxyl moiety repeating units, said sum equals 200 mole percent; (6) A sulfopolyester comprising: (a) residues of one or more dicarboxylic acids; (b) greater than 8.5 mole percent of residues of at least one sulfomonomer; and (c) residues of one or more diols, wherein the sulfopolyester comprises a ratio of carboxylate end groups to acid end groups of at least 0.35, wherein the sulfopolyester contains substantially equimolar ratios of acid moiety repeating units to hydroxy moiety repeating units, wherein the acid moiety repeating units equal 100 mole percent, the hydroxy moiety repeating units equal 100 mole percent, and wherein all of said mole percents are based on the sum of all of the acid and hydroxy moiety repeating units, said sum equals 200 mole percent; and (7) A sulfopolyester comprising: (a) residues of one or more dicarboxylic acids; (b) greater than 8.5 mole percent of residues of at least one sulfomonomer; and (c) residues of one or more diols, wherein the sulfopolyester comprises carboxylate end groups in an amount of at least 12 μeq / g, wherein an aqueous dispersion comprising 25 weight percent of the sulfopolyester exhibits a dispersion viscosity of at least 30 cP and less than 100 cP at 22°C, wherein the sulfopolyester contains substantially equal molar proportions of acid moiety repeating units and hydroxyl moiety repeating units, wherein the acid moiety repeating units equal 100 mole percent, the hydroxyl moiety repeating units equal 100 mole percent, and wherein all of said mole percentages are based on the sum of all of the acid and hydroxyl moiety repeating units, said sum equals 200 mole percent.

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