Degradable elastic polyurethane composition

Abstract

The degradable polyurethaneurea composition may be a fiber comprising a glycol, a diisocyanate, and a chain extender, wherein the glycol component comprises greater than 50% by weight of a polyester glycol having a number average molecular weight of about 450 to about 3300, and the fiber is degradable.

Description

[Technical Field]

[0001] The present invention relates to the preparation of segmented polyurethanes and poly(urethane ureas) with soft segments engineered to enhance susceptibility to degradation, including but not limited to biodegradation, by incorporating hydrolytically unstable polyester glycols into the soft segments, compositions comprising these polymers, and articles of manufacture made from these compositions. In one non-limiting embodiment, the present invention relates to spandex fibers made from these polymers with engineered soft segment susceptibility to biodegradation, and articles of manufacture made from these spandex fibers.

[0002] Overview of related technologies There has been growing interest in degradable, biodegradable, and / or compostable materials as alternative sustainable solutions to reducing plastic residues in the environment. Polyurethane or poly(urethane urea) fibers are incorporated into clothing and mixed-component articles to impart stretch and contractibility to them. Recycling of these products can be achieved through mechanical separation or chemical depolymerization, which can occur through several routes, including glycolysis, methanolysis, and hydrolysis. However, because polyurethane or poly(urethane urea) polymers are physically and chemically different from the other fiber components of the aforementioned articles and because their incorporation levels are relatively low, these fibers can be a limiting factor in mechanical or chemical recycling processes. Given the limited lifespan of clothing, especially disposable garments such as infant hygiene products, the market demands biodegradable fiber options.

[0003] Biodegradation is the process by which substances are broken down into smaller molecules through interactions with natural organisms such as bacteria, fungi, algae, and other living organisms. Biodegradable polymers are degraded by chain scission induced by the activity of biological enzymes, which breaks weak sections of the polymer chain, reducing its molecular weight and breaking it down into the smallest possible components. Composting is also a deliberate biodegradation process, where decomposition occurs in a controlled industrial process where conditions such as oxygen, moisture content, and temperature can be adjusted, resulting in weight loss. The decomposition products are metabolized and utilized by various microorganisms, converting them into carbon dioxide, water, and bacterial cell components.

[0004] In the case of polyurethane or poly(urethane-urea) fibers, susceptibility to biodegradation is primarily imparted by the glycol or soft segment structure of the resulting polymer. Traditionally, polyethers such as poly(tetramethylene ether) glycol (PTMEG) are used, capped with methylene diphenyl diisocyanate (MDI) for environmental resistance and durability. In general, parameters that can affect a polymer's biodegradation rate can be summarized as molecular weight, chain mobility, morphology (crystalline vs. amorphous), synthesis method, hydrophilicity (wettability), type of organism, and other raw materials. The greatest flexibility in producing biodegradable fibers is imparted by varying the raw material input, which determines the location of molecular weaknesses targeted by the enzymatic degradation process. This process can also be intentional, utilizing the aforementioned chemical recycling methods to accelerate the degradation of chemically susceptible fibers.

[0005] U.S. Patent No. 8,357,767 discloses high-elasticity polyurethane compositions incorporating polyester backbones extended with linear aliphatic glycols, which are used in extruded articles. CN Patent No. 109338504 discloses the use of polyester glycols that are readily biodegradable in limited amounts. Summary of the Invention

[0006] The prior art has failed to provide degradable polyurethaneurea compositions or fibers with the desired properties for apparel and hygiene applications, particularly in the area of ​​high polyester content (greater than 50% by weight of the total glycol content) extruded articles or other compositions with inherently selectable degradability characteristics.

[0007] A polyurethaneurea fiber comprising a glycol, a diisocyanate, and a chain extender, wherein the glycol component comprises greater than 50% by weight of a polyester glycol having a number average molecular weight of about 450 to about 3300, and the fiber is degradable. The fiber can provide a normalized recovery force, expressed as the recovery force at 200% elongation on the fifth unloading cycle, of at least 0.022 centiNewtons / dtex.

[0008] An article of manufacture comprising a polyurethaneurea fiber comprising a glycol, a diisocyanate, and a chain extender, wherein the glycol component comprises greater than 50% by weight of a polyester glycol having a number average molecular weight of about 450 to about 3300, and wherein the fiber is degradable.

[0009] A composition comprising a glycol component, a diisocyanate, and a chain extender, wherein the glycol component comprises a polyester glycol having a number average molecular weight of about 450 to about 3300, and a biodegradation-enhancing additive in an amount of about 0.1% to about 50% by weight of the composition, and the composition is degradable.

[0010] Also included are compositions comprising a glycol component, a diisocyanate, and a chain extender, wherein the glycol component comprises a polyester glycol having a number average molecular weight of about 450 to about 3300, and a degradability-enhancing additive in an amount of about 0.1% to about 50% by weight of the composition, and wherein the composition is degradable.

[0011] Also included are methods for degrading spandex, which involve subjecting one or more compositions, articles, or fibers comprising the polyurethaneureas disclosed herein to conditions that result in degradation of the polymer structure. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a table showing the components of the fiber and its constituent polymers in terms of glycol type, glycol molecular weight, NCO% of capped glycol, and chain extender. [Figure 2] This table summarizes the biodegradation rate over a four-week period for each fiber sample screened using the enzymatic method. Fiber degradation occurs with both a microscale loss of fiber structure (leading to mass loss) and a molecular-scale loss of polymer chain structure (leading to molecular weight loss). Molecular weight loss is a more sensitive measure of degradation due to its detection threshold, and therefore, while there is a correlation between measurements, the actual rates do not overlap. The comparative examples, despite being polyether or polyester based, do not demonstrate a significant degree of biodegradability. [Figure 3] FIG. 3 is a schematic diagram of the tabular data of FIG. 2 presented in terms of molecular weight loss. [Figure 4] FIG. 3 is a schematic diagram of the tabulated data of FIG. 2 presented in terms of mass loss. [Figure 5] 1 is a schematic diagram showing the relationship between shrinkage force (5TM2) as assessed by molecular weight loss and biodegradation rate. Fibers containing a single glycol demonstrate a clear relationship between higher biodegradation rate and lower shrinkage force. Fibers containing mixed glycols (Examples 4 and 5) both exhibit greater than 10% molecular weight loss while maximizing shrinkage force properties. [Figure 6] 1 is a table showing fiber properties obtained from a 44 dtex dry spinning process. [Figure 7] Decomposition rate by additive [Figure 8] Mn loss due to additives [Figure 9] Mw loss due to additives DETAILED DESCRIPTION OF THE INVENTION

[0013] Definition: For purposes of the present invention, the term "degradable" is intended to include compositions that are susceptible to chemical breakdown. For example, a molecule is degradable if it tends to break down into smaller molecules. Degradation can occur through composting (including industrial composting), chemical degradation, biodegradation, marine degradation, anaerobic digestion, and any other known process.

[0014] As used herein, "biodegradable" means a material that meets the ASTM D5338 test standard for aerobic biodegradability under controlled conditions.

[0015] As used herein, "high shrink force" means a 5TM2 value of greater than 1.2 cN for a 44 dtex fiber produced by dry spinning.

[0016] By "enzymatically biodegradable" is meant a % molecular weight loss of at least 10% after 4 weeks of exposure to esterase enzymes.

[0017] Described herein are compositions comprising a series of segmented polyurethanes or poly(urethane ureas) with engineered soft segment structures, produced by incorporating variable amounts of polyester glycols into the capping process. The incorporation of polyester glycols into the polymer backbone places ester linkages with specific structures within the polymer backbone, introducing weak points for degradation reactions.

[0018] This process allows for the right balance between the low modulus, high elongation, and comfort properties of polyether-based polyurethanes and poly(urethaneureas) and the high retractive force, low cost, and rapid degradation properties of polyester-based polyurethanes and poly(urethaneureas), producing polymers with properties not achievable with either glycol alone.

[0019] Elastomeric polyurethanes such as spandex and elastane (the terms are used interchangeably herein) contain at least 85% of the fiber-forming material as segmented polyurethanes or poly(urethane ureas) that contain alternating soft and hard segments along the polymer chain. The properties of spandex fibers depend largely on the chemical structure and segment length (or molecular weight) of both the soft and hard segments of the polymer, as well as the specific structure or arrangement of the soft segments.

[0020] In a typical conventional process for producing spandex polymers, a glycol (also referred to herein as a polyol), which is a polyether, polyester, or polycarbonate diol (including copolymers or mixtures thereof), is reacted with an excess of diisocyanate to form an isocyanate-terminated polyurethane or poly(urethane urea) prepolymer. This prepolymer is then diluted with a solvent and chain-extended with a short-chain diol or diamine to increase the length of the polymer chain. Terminators can be used to control the molecular weight of the polymer. In this type of conventional process, soft segments are formed during the prepolymer formation stage, and hard segments are formed during the chain extension stage. Thus, the resulting polymer chain consists solely of alternating soft and hard segments, each of a fixed chemical composition of a single glycol or diamine mixture.

[0021] In some embodiments, incorporating polyester glycols, such as copolymers of ethanediol, butanediol, and adipic acid (hereinafter "2G / 4G-6"), into the capping or chain extension process introduces a variable soft segment sequence, allowing the resulting polymer to consist of alternating segments of polyester and polyether functional groups. Introducing a glycol mixture early in the process allows for greater variability in the sequence of soft segment chemistry. This can be accomplished later by blending the resulting polymers composed of a single glycol and isocyanate type, but can also involve introducing blends of each. This process, followed by spinning, introduces ester linkages into the spandex fiber backbone, providing labile carbonyls that can be selectively degraded by enzymatic activity, typically through intentional biodegradation and composting. Other examples of polyester glycols are described below.

[0022] In some embodiments, polymer compositions comprising segmented polyurethanes or poly(urethane ureas) according to the present invention are based on glycols having a molecular weight of 450 to 3300, and preferably have at least 25% polyester content and at least 1.8% NCO to provide an appropriate balance of polymer properties and structural characteristics of the resulting article.

[0023] The present invention also provides polymers made with certain blend ratios of polyether and polyester glycols via glycol blends, capped glycol blends, or polymer solution blends.

[0024] The present invention also provides fibers comprising the polymer compositions of the present invention, as well as articles of manufacture comprising, at least in part, fibers based on the compositions described herein.

[0025] Non-limiting examples of such articles of manufacture of the present invention include fabrics and garments. In one non-limiting embodiment, the fabrics and garments are intended for apparel and / or hygiene applications. The article may include a stretchable laminate including at least a first layer and a second layer independently selected from the group consisting of a nonwoven layer, a film, and combinations thereof. The article is a stretchable nonwoven laminate, and the fibers are adjacent to or integrated into the laminate.

[0026] The articles may include disposable hygiene products, disposable diapers, training pants or adult incontinence devices or products, menstrual devices or garments or products thereof, bandages, wound dressings, surgical drapes, surgical gowns, surgical masks or other hygienic protective masks, sanitary gloves, head covers, headbands, ostomy bags, bed pads or bed sheets.

[0027] The composition of some embodiments may comprise a form selected from the group consisting of a dispersion, a solution, a film, an extrudate, and a fiber.

[0028] In one non-limiting embodiment of the present invention, the polymer composition is useful for making spandex with high retractive force, low hysteresis, and improved susceptibility to biodegradation.

[0029] In one non-limiting embodiment, spandex fibers are spun from the polymer composition. The spandex fibers can be, for example, but not limited to, dry-spun, wet-spun, or melt-spun. In one non-limiting embodiment, the spandex fibers are dry-spun.

[0030] The production of polyurethanes can be carried out by batch polymerization or by use of a continuous polymerization reactor.

[0031] Non-limiting examples of diisocyanates useful in the present invention include, but are not limited to, 4,4'-methylenebis(phenylisocyanate) (also known as 4,4-diphenylmethane diisocyanate (MDI)), 2,4'-methylenebis(phenylisocyanate), 4,4'-methylenebis(cyclohexylisocyanate), 1,4-xylene diisocyanate, 1,4-bis(isocyanatomethyl)cyclohexane, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, and mixtures thereof. Examples of specific polyisocyanates include Takenate® 500 and FORTIMO® 1,4-H6XD1 (Mitsui Chemicals), Mondur® MB (Bayer), Lupranate® M (BASF), and Isonate® 125MDR (Dow Chemical), and combinations thereof.

[0032] The glycol or polyol component may contain two or more glycols, but must contain at least 50% polyester glycol by weight. Blends may contain greater than 50% to 100% polyester glycol by weight. This includes blends with greater than 60% polyester, greater than 75% polyester glycol, or greater than 90% polyester glycol by weight. The polyester glycol may have a number average molecular weight of about 450 to about 3300. This may include a molecular weight of about 1000 to about 3000. The molecular weight may also be less than 2500, e.g., 500 to about 2500, or about 1000 to about 2000. The polyester glycol may be combined with one or more other glycols, which may be either polyester glycols, polyether glycols, or polycarbonate glycols. The additional glycol or glycols may have a number average molecular weight of about 400 to about 4000.

[0033] Examples of useful glycols include polyether glycols such as poly(tetramethylene ether) glycol (PTMEG), copolyether glycols such as poly(tetramethylene ether-co-ethylene ether) glycol and poly(tetramethylene ether-co-2-methyltetramethylene ether) glycol, polyester and copolyester glycols such as polycaprolactone diol, and those produced by the condensation polymerization of low molecular weight aliphatic dicarboxylic acids and diols having 12 or fewer carbon atoms per molecule, or mixtures thereof, and polycarbonate glycols produced by the condensation polymerization of aliphatic diols with phosgene, dialkyl carbonates, or diaryl carbonates. Other examples of polyester glycols include poly(2,2-dimethyl-1,3-propane)diol, neopentyl glycol, poly(2,2-dimethyl-1,3-propane dodecanedioate)glycol, poly(ethylene-co-1,2-propylene adipate)glycol, poly(hexamethylene-co-2,2-dimethyltrimethylene adipate)glycol, and poly(ethylene-co-butylene adipate)glycol. Specific commercially available glycols are PTG-L glycol (Hodogaya Chemical Co., Ltd., Tokyo, Japan), ETERNACOLL® diol (Ube Industries, Ltd., Tokyo, Japan), and STEPANPOL® polyol (Stepan, Illinois, USA).

[0034] In one embodiment, examples of usable polyester polyols include, but are not limited to, ester glycols having two or more hydroxy groups, prepared by the condensation polymerization of low molecular weight aliphatic polycarboxylic acids and polyols having 12 or fewer carbon atoms per molecule, or mixtures thereof. Examples of suitable polycarboxylic acids include, but are not limited to, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, thiodibutyric acid, sulfonyldibutyric acid, undecanedicarboxylic acid, and dodecanedicarboxylic acid. Examples of polyols suitable for preparing polyester polyols include, but are not limited to, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol. A linear bifunctional polyester polyol having a melting point of about 5° C. to 50° C. is an example of a specific polyester polyol. Other suitable polyols include diethylene glycol, propane-1,2-diol, butane-1,3-diol, butane-1,4-diol, hexane-1,6-diol, hexahydro-p-xylylene glycol, 2,2-dimethylpropane-1,3-diol, 2,2-diethylpropane-1,3-diol, hydroxyalkylation products of the above glycols, etc. Polyesters of lactones (e.g., ε-caprolactone) can also be used as starting materials. Copolyesters can also be included.

[0035] The glycol component, which includes a mixture of two or more glycols, may include a mixture of poly(tetramethyl ether) glycol and polyester glycol, or a mixture of copolyether glycol and polyester glycol.

[0036] In embodiments, examples of polyether glycols that can be used include glycols having two or more hydroxy groups obtained from the ring-opening polymerization and / or copolymerization of ethylene oxide, propylene oxide, trimethylene oxide, tetrahydrofuran, and 3-methyltetrahydrofuran, or the condensation polymerization of polyhydric alcohols such as diols or mixtures of diols containing fewer than 12 carbon atoms in each molecule, such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol. One particularly suitable glycol is poly(tetramethylene ether) glycol having a molecular weight of about 1,700 to about 2,100, such as Terathane® 1800, which has a functionality of 2. Copolymers can include poly(tetramethylene-co-ethylene ether) glycol.

[0037] In one embodiment, examples of usable polycarbonate polyols include, but are not limited to, carbonate glycols having two or more hydroxy groups, prepared by condensation polymerization of phosgene, chloroformates, dialkyl carbonates, or diallyl carbonates with low molecular weight aliphatic polyols containing 12 or fewer carbon atoms per molecule, or mixtures thereof. Examples of polyols suitable for preparing polycarbonate polyols include, but are not limited to, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol. A linear bifunctional polycarbonate polyol having a melting point of about 5°C to about 50°C is one example of a specific polycarbonate polyol.

[0038] Non-limiting examples of diamine chain extenders useful in making segmented poly(urethane urea)s according to the present invention include 1,2-ethylenediamine, 1,4-butanediamine, 1,2-butanediamine, 1,3-butanediamine, 1,3-diamino-2,2-dimethylbutane, 1,6-hexamethylenediamine, 1,12-dodecanediamine, 1,2-propanediamine, 1,3-propanediamine, 2-methyl-1,5-pentanediamine, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane, 2,4-diamino-1-methylcyclohexane, N-methylaminobis(3-propylamine), 1,2-cyclohexane, Examples of suitable diamines include one or more diamines selected from hexanediamine, 1,4-cyclohexanediamine, 4,4'-methylene-bis(cyclohexylamine), isophoronediamine, 2,2-dimethyl-1,3-propanediamine, meta-tetramethylxylenediamine, 1,3-diamino-4-methylcyclohexane, 1,3-cyclohexanediamine, 1,1-methylenebis(4,4'-diaminohexane), 3-aminomethyl-3,5,5-trimethylcyclohexane, 1,3-pentanediamine (1,3-diaminopentane), m-xylylenediamine, and Jeffamine® (Texaco). When a segmented polyurethane having a urethane hard segment is desired, the chain extender is a diol. Examples of such diols that can be used include, but are not limited to, ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-trimethylenediol, 2,2,4-trimethyl-1,5-pentanediol, 2-methyl-2-ethyl-1,3-propanediol, 1,4-bis(hydroxyethoxy)benzene, and 1,4-butanediol, and mixtures thereof.

[0039] Non-limiting examples of chain terminators useful in the present invention include one or more monofunctional amines selected from ethylamine, propylamine, isopropylamine, n-butylamine, sec-butylamine, tert-butylamine, isobutylamine, isopentylamine, 1-hexylamine, 1-octylamine, 2-ethyl-1-hexaneamine, cyclohexylamine, N,N-diethylamine, N-ethyl-N-propyl, N,N-diisopropylamine, N-tert-butyl-N-methylamine, N-tert-butyl-N-benzylamine, N,N-dicyclohexylamine, N-ethyl-N-isopropylamine, N-tertbutyl-N-isopropylamine, N-isopropyl-N-cyclohexylamine, N-ethyl-N-cyclohexylamine, N,N-diethanolamine, and 2,2,6,6-tetramethylpiperidine.

[0040] A non-limiting example of a solvent for use in the present invention is N,N-dimethylacetamide (DMAc). Other solvents suitable for polyurethanes and / or polyurethaneureas may also be included.

[0041] The following is an exemplary, non-limiting list of types of additives that may optionally be included in polyurethane and poly(urethaneurea) compositions: antioxidants, UV stabilizers, colorants, pigments, crosslinkers, phase change materials (paraffin wax), antimicrobial agents, minerals (e.g., copper), microencapsulated additives (e.g., aloe vera, vitamin E gel, aloe vera, seaweed, nicotine, caffeine, flavors or aromas), nanoparticles (e.g., silica or carbon), nanoclay, calcium carbonate, tar, flame retardants, anti-blocking agents, chlorine degradation resistant additives, vitamins, pharmaceuticals, fragrances, conductive additives, and dye and / or dye aids (such as quaternary ammonium salts). Other additives that can be added to polyurethane and poly(urethane urea) compositions include adhesion promoters, antistatic agents, creep resistance agents, optical brighteners, coalescing agents, conductive additives, luminescent additives, lubricants, organic and inorganic fillers, preservatives, texturizing agents, thermochromic agents, pest repellents, and spandex compositions such as wetting agents, stabilizers (hindered phenols, zinc oxide, hindered amines), slip agents (silicone oils), and combinations thereof. Additives can also include degradability-enhancing or degradation-retarding additives. Degradability-enhancing additives are described in more detail herein.

[0042] The additives may provide one or more beneficial properties including dyeability, hydrophobicity (e.g., polytetrafluoroethylene (PTFE)), hydrophilicity (e.g., cellulose), friction control, chlorine resistance, degradation resistance (e.g., antioxidants), adhesion and / or fusibility (e.g., adhesives and adhesion promoters), flame retardancy, antimicrobial properties (silver, copper, ammonium salts), barrier properties, conductivity (carbon black), tensile properties, color, luminescence, recyclability, biodegradability, fragrance, tack control (e.g., metal stearates), tactile properties, hardenability, thermal regulation (e.g., phase change materials), nutraceuticals, matting agents such as titanium dioxide, stabilizers such as hydrotalcite, mixtures of huntite and hydromagnesite, ultraviolet light filters, and combinations thereof.

[0043] The degradability-enhancing additive may be selected from the group consisting of cellulose esters (cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate), soluble celluloses (methylcellulose, ethylcellulose, hydroxypropylmethylcellulose), insoluble celluloses (microcrystalline cellulose, nanocrystalline cellulose, cellulose fibrils), polyvinyl alcohol, cetyl alcohol, and starch. Any of the compositions, fibers, and / or articles may contain one or more degradability-enhancing additives. A suitable amount of the degradability-enhancing additive may be in an amount of up to about 5%. Depending on the desired level of degradability, the amount may be 0.01% to about 5%, about 1% to about 5%, or about 1% to about 2% by weight of the composition.

[0044] In some embodiments, the linear density of useful yarns can range from about 15 denier (D) (16.5 dtex) to about 450 denier, including from about 15 denier to about 300 denier (330 dtex), and for apparel applications, from about 30 denier to 100 denier (33 dtex to 110 dtex). Heavier deniers, such as above 450 denier, may be useful for achieving other properties. Historically, higher deniers, such as 500 to 1200 denier, may be preferred for hygiene end uses.

[0045] As used herein, the terms "nonwoven" or "nonwoven material" refer to materials made from continuous (long) filaments (fibers) and / or discontinuous (short) filaments (fibers) by processes such as spunbonding, meltblowing, carding, etc. Nonwovens do not have a woven or knitted filament pattern.

[0046] As used herein, the term "nonwoven web" refers to a manufactured sheet, web, or batt of directionally or randomly oriented fibers bonded together by friction, and / or cohesion, and / or adhesion, excluding paper and products that are woven, knitted, tufted, stitch-bonded, or wet-milled felted incorporating binding yarns or filaments (with or without additional needling). The fibers may be natural or artificial in origin and may be staple or continuous filaments, or formed in situ. Commercially available fibers may have diameters ranging from less than about 0.001 mm to greater than about 0.2 mm and come in a variety of forms, including staple fibers (also known as staple or chopped), continuous single fibers (filaments or monofilaments), untwisted bundles of continuous filaments (tows), and twisted bundles of continuous filaments (yams). Nonwoven webs may be formed by a variety of processes, including meltblowing, spunbonding, solvent spinning, electrospinning, carding, and airlaying. The basis weight of a nonwoven web is typically expressed in grams per square meter (g / m2 or gsm).

[0047] As used herein, the terms "joined," "coupled," or "attached" encompass configurations in which an element is directly secured to another element by being directly secured to the other element, and configurations in which an element is indirectly secured to another element by being secured to an intermediate member that is in turn secured to the other element.

[0048] In one non-limiting embodiment, the process steps involved in producing the segmented polyurethanes or poly(urethane ureas) of the present invention can be a batch process, a continuous process, or a combination thereof. In one non-limiting embodiment, the individual glycols are capped by a batch process, and then combined in a set ratio in the form of capped glycols to produce a polymer with chain extension and termination in a solvent by a continuous polymerization process.

[0049] In other non-limiting embodiments, the step involving glycol capping with a diisocyanate, either a single glycol or a mixture of glycols, is typically carried out with heating, typically in the temperature range of 50-100°C, with or without the use of a catalyst.

[0050] In other non-limiting embodiments, the glycol can be subjected to a capping reaction with two or more isocyanates, where each glycol used in the polyurethane or poly(urethane urea) polymer is capped with a different type of diisocyanate.

[0051] In one non-limiting embodiment, biodegradable polyurethane or poly(urethane urea) elastic fibers are spun from a solution-polymerized polyurethane polymer solution by a prepolymer method.

[0052] According to the present disclosure, biodegradable polyurethane or poly(urethane urea) elastic fibers are used to elasticize nonwoven laminates. The biodegradable polyurethane or poly(urethane urea) elastic fibers can be contained within or juxtaposed with the nonwoven laminate.

[0053] In one non-limiting embodiment, the biodegradable polyurethane or poly(urethane urea) elastic fibers are first stretched and then applied or incorporated into the nonwoven laminate in a stretched state.

[0054] As shown in the figures and examples below, this process for producing spandex polymers based on polyester or polyether glycol blends is useful for producing segmented polyurethanes or poly(urethane ureas) with biodegradable and tensile properties. [Example]

[0055] Test Method Viscosity of the polymer solutions was measured according to the method of ASTM D1343-69 using a Model DV-8 falling ball viscometer (Duratech Corp., Waynesboro, VA) operated at 40°C and reported in poise.

[0056] The solids content in the polymer solution was measured by a microwave-heated moisture / solids analyzer, Smart System 5 (CEM Corp., Matthews, NC).

[0057] The isocyanate percent (NCO%) of the capped glycol prepolymer was determined using potentiometric titration according to the method of S. Siggia, "Quantitative Organic Analysis via Functional Group," 3rd Edition, Wiley & Sons, New York, pages 559-561 (1963).

[0058] The strength and elastic properties of spandex fibers were measured according to the general method of ASTM D 2731-72. Three filaments, a 5.0 cm gauge length, and 0-300% elongation cycles were used for each measurement. Samples were cycled five times at a constant elongation rate of 50 centimeters per minute. The load force (1TP200), which is the stress on the spandex at initial elongation, was measured at 200% elongation on the first cycle and is reported in centiNewtons (cN) for a given linear density. The unload force (5TM200), which is the stress at 200% elongation on the fifth unloading cycle, is also reported in centiNewtons. The elongation at break and tenacity were measured on the sixth elongation cycle. The stress decay (%) was measured as the percentage stress reduction on the fifth cycle after a 30-second delay at 300% elongation. %SD=(5LP300-5UP300)×100 / 5LP300 where 5LP300 and SUP300 (centinewtons) are the loading and unloading forces, respectively, at 300% elongation of the sample. The percent set was also measured for samples that underwent five 0-300% elongation / relaxation cycles. In this case, the percent set (%SET) was calculated as follows: %SET=100×(Lf-Lo) / Lo where Lo and Lf are the lengths of the filament (yarn) when held straight and without tension before and after five stretch / relaxation cycles, respectively. Molecular weight (MW) was assessed by gel permeation chromatography (GPC) on an Agilent GPC column using fixed weight polystyrene as a reference.

[0059] Degradation properties were evaluated by an accelerated degradation test in which the yarn was exposed to purified enzymes. An esterase enzyme from porcine liver was used with an enzyme activity of ≥15 units, which is the standardized activity required to hydrolyze 1.0 micromoles of ethyl butyrate to butyric acid and ethanol per minute at 25°C and pH 8.0. A 50 mg sample of yam was treated with 10 mg of esterase in 2 mL of phosphate-buffered saline (PBS) at pH 7.4 for 4 weeks. Weekly, the enzyme solution was removed and replaced, and samples were collected for mass and molecular weight measurements.

[0060] The rate of degradation at the fiber scale was assessed by mass loss, expressed as the percentage of the original mass lost as dissolved material, with 0 and 4 designating the sample age in weeks exposed to the enzyme solution. Mass loss (%)=(ME0-ME4) / ME0

[0061] The rate of degradation at the molecular level is assessed by molecular weight loss, which is expressed as a percentage of the original fiber molecular weight in buffer that undergoes polymer chain scission and compared to the molecular weight of the fiber exposed to the enzyme. Molecular weight loss (%) = (MW B -MW E ) / MW B

[0062] Having outlined embodiments of the present disclosure, the following examples illustrate some additional embodiments of the present disclosure. While embodiments of the present disclosure will be described in conjunction with the following examples and corresponding text and figures, there is no intent to limit the embodiments of the present disclosure to this description. On the contrary, it is intended to cover all alternatives, modifications, and equivalents that may be included within the spirit and scope of the present disclosure.

[0063] Materials List PTMEG1800 is a poly(tetramethylene ether) glycol supplied by Dairen with a number average molecular weight of 1800 grams / mole.

[0064] 2G / 4G-6 is a polyester glycol (polymer of hexanedioic acid, 1,4-butanediol, and 1,2-ethanediol) with an average molecular weight of 1500 grams / mole.

[0065] Isonate® 125MDR or MDI is a mixture of diphenylmethane diisocyanates containing about 98% 4,4′-MDI isomer and about 2% 2,4′-MDI isomer (commercially available from Dow Company, Midland, Michigan).

[0066] EDA represents ethylenediamine as a chain extender, DEA represents N,N-diethylamine as a chain terminator, and DMAc represents N,N-dimethylacetamide as a solvent.

[0067] Example The following examples are provided to illustrate the invention of using polyester glycols or glycol blends to produce spandex fibers with selectable biodegradation rates, achieving the target fiber properties of high elongation, high retractive force, and a lower, controlled biodegradation rate. This method allows for careful control of spandex manufacturing costs, balancing the chemical durability and elasticity of polyether glycols with the hydrolytic susceptibility and low raw material costs of polyether glycols.

[0068] The examples are provided for illustrative purposes only and are not intended to limit the scope of the invention.

[0069] Example 1 A prepolymer with a molecular weight of 1485 g / mol (a polymer of hexanedioic acid, 1,4-butanediol, and 1,2-ethanediol) was reacted with 200 ppm of 85% phosphoric acid and 4,4'-diphenylmethane diisocyanate (MDI) in a 3.75:1.00 (weight ratio) under neat conditions in a batch polymerization process at 90 °C for 120 minutes at the specified reaction rate. The target residual isocyanate group content after the reaction was 2.60 wt%. The capping ratio (molar ratio of isocyanate to glycol) was 1.58. 348.31 g of the resulting prepolymer was dissolved in 613.55 g of DMAc at 60 °C, and a chain extender solution containing 6.44 g of ethylenediamine, 0.48 g of diethylamine, and 106.78 g of DMAc was added at 80 °C with vigorous stirring to obtain a 33 wt% viscosity-adjusting polymer solution.

[0070] Example 2 A polyester glycol (polymer of hexanedioic acid, 1,4-butanediol, and 1,2-ethanediol) with a molecular weight of 987 g / mol was reacted with 200 ppm of 85% phosphoric acid and 4,4'-diphenylmethane diisocyanate (MDI) in a weight ratio of 2.79:1.00, respectively, under neat conditions in a batch polymerization process at 90 °C for 60 minutes at the specified reaction rate. The target residual isocyanate group content after the reaction was 2.60 wt%. The capping ratio (molar ratio of isocyanate to glycol) was 1.42. 373.66 g of the resulting prepolymer was dissolved in 593.55 g of DMAc at 60 °C, and a chain extender solution containing 6.95 g of ethylenediamine, 0.36 g of diethylamine, and 113.29 g of DMAc was added at 80 °C with vigorous stirring to obtain a 35 wt% viscosity-adjusting polymer solution.

[0071] Example 3 A prepolymer was obtained by reacting a polyester glycol (a polymer of hexanedioic acid, 1,4-butanediol, and 1,2-ethanediol) with 200 ppm of 85% phosphoric acid and 4,4'-diphenylmethane diisocyanate (MDI) in a weight ratio of 4.63:1.00, respectively, in a batch polymerization process at 100°C for 60 minutes under neat conditions. The target residual isocyanate group content after the reaction was 2.60 wt%. The capping ratio (molar ratio of isocyanate to glycol) was 1.77. The obtained 334.36 g of prepolymer was dissolved in 588.89 g of DMAc at 60°C, and a chain extender solution containing 6.18 g of ethylenediamine, 0.47 g of diethylamine, and 102.58 g of DMAc was added thereto at 80°C with vigorous stirring to obtain a viscosity-adjusting polymer solution having a concentration of 33 wt%.

[0072] Example 4 A blend of 75 wt% polyester glycol (a polymer of hexanedioic acid, 1,4-butanediol, and 1,2-ethanediol) with a molecular weight of 1,475 g / mol and 25 wt% poly(tetramethylene ether) glycol (PTMEG) was reacted with 200 ppm of 85% phosphoric acid and 4,4'-diphenylmethane diisocyanate (MDI) in a 3.73:1.00 (weight ratio) in a batch polymerization process at 100 °C for 75 minutes under neat conditions, with the specified reaction rate to obtain a prepolymer. The target residual isocyanate group content after the reaction was 2.60 wt%. The capping ratio (molar ratio of isocyanate to glycol) was 1.58. The obtained 348.65 g of prepolymer was dissolved in 581.11 g of DMAC at 60°C, and a chain extender solution containing 6.41 g of ethylenediamine, 0.56 g of diethylamine, and 107.37 g of DMAc was added thereto at 80°C with vigorous stirring to obtain a viscosity-adjusting polymer solution having a concentration of 34 wt%.

[0073] Example 5 A blend of 50 wt% polyester glycol (polymer of hexanedioic acid, 1,4-butanediol, and 1,2-ethanediol) with a molecular weight of 1,470 g / mol and 50 wt% poly(tetramethylene ether) glycol (PTMEG) was reacted with 200 ppm of 85% phosphoric acid and 4,4'-diphenylmethane diisocyanate (MDI) in a 3.72:1.00 (weight ratio) batch polymerization process at 100 °C for 75 minutes under neat conditions to obtain a prepolymer. The target residual isocyanate group content after the reaction was 2.60 wt%. The capping ratio (molar ratio of isocyanate to glycol) was 1.58. The obtained 350.09 g of prepolymer was dissolved in 646.76 g of DMAc at 60°C, and a chain extender solution containing 6.40 g of ethylenediamine, 0.65 g of diethylamine, and 108.39 g of DMAc was added thereto at 80°C with vigorous stirring to obtain a viscosity-adjusting polymer solution having a concentration of 32 wt%.

[0074] Example 6 A prepolymer was obtained by reacting a polyester glycol (a polymer of hexanedioic acid, 1,4-butanediol, and 1,2-ethanediol) with 200 ppm of 85% phosphoric acid and 4,4'-diphenylmethane diisocyanate (MDI) in a weight ratio of 3.63:1.00, respectively, in a batch polymerization process at 100°C for 75 minutes under neat conditions. The target residual isocyanate group content after the reaction was 2.80 wt%. The capping ratio (molar ratio of isocyanate to glycol) was 1.63. 350.75 g of the obtained prepolymer was dissolved in 609.94 g of DMAc at 60°C, and a chain extender solution containing 6.92 g of ethylenediamine, 0.65 g of diethylamine, and 116.45 g of DMAc was added thereto at 80°C with vigorous stirring to obtain a viscosity-adjusting polymer solution having a concentration of 33 wt%.

[0075] Example 7 A polyester glycol (polymer of hexanedioic acid, 1,4-butanediol, and 1,2-ethanediol) with a molecular weight of 1,480 g / mol was reacted with 200 ppm of 85% phosphoric acid and 4,4'-diphenylmethane diisocyanate (MDI) in a weight ratio of 3.98:1.00, respectively, under neat conditions in a batch polymerization process at 100 °C for 75 minutes at the specified reaction rate. The target residual isocyanate group content after the reaction was 2.20 wt%. The capping ratio (molar ratio of isocyanate to glycol) was 1.48. 344.04 g of the resulting prepolymer was dissolved in 587.80 g of DMAc at 60 °C, and a chain extender solution containing 5.36 g of ethylenediamine, 0.52 g of diethylamine, and 90.39 g of DMAc was added at 80 °C with vigorous stirring to obtain a 34 wt% viscosity-adjusting polymer solution.

[0076] Example 8 A prepolymer was obtained by reacting a polyester glycol (a polymer of hexanedioic acid, 1,4-butanediol, and 1,2-ethanediol) with 200 ppm of 85% phosphoric acid and 4,4'-diphenylmethane diisocyanate (MDI) in a weight ratio of 3.74:1.00, respectively, in a batch polymerization process under neat conditions at 100°C for 75 minutes at the specified reaction rate. The target residual isocyanate group content after the reaction was 2.60 wt%. The capping ratio (molar ratio of isocyanate to glycol) was 1.58. 348.48 g of the obtained prepolymer was dissolved in 584.01 g of DMAc at 60°C, and a chain extender solution containing 5.12 g of ethylenediamine, 2.48 g of 2-methylpentamethylenediamine, 0.57 g of diethylamine, and 106.23 g of DMAc was added thereto at 80°C with vigorous stirring to obtain a viscosity-adjusting polymer solution having a concentration of 34 wt%.

[0077] Example 9 A prepolymer was obtained by reacting a polyester glycol (a polymer of hexanedioic acid, 1,4-butanediol, and 1,2-ethanediol) with 200 ppm of 85% phosphoric acid and 4,4'-diphenylmethane diisocyanate (MDI) in a weight ratio of 6.54:1.00, respectively, in a batch polymerization process at 100°C for 120 minutes under neat conditions at the specified reaction rate. The target residual isocyanate group content after the reaction was 2.00 wt%. The capping ratio (molar ratio of isocyanate to glycol) was 1.81. 317.07 g of the obtained prepolymer was dissolved in 525.78 g of DMAc at 60°C, and a chain extender solution containing 3.63 g of ethylenediamine, 1.75 g of 2-methylpentamethylenediamine, 0.24 g of diethylamine, and 70.48 g of DMAc was added thereto at 80°C with vigorous stirring to obtain a viscosity-adjusting polymer solution having a concentration of 35 wt%.

[0078] Examples 1 to 9 and Comparative Examples The polymer solution prepared as described above was individually mixed with slurry-form additives at levels including, based on the total weight of solids, about 1.35% LOWINOX® GP45 antioxidant and 0.50% silicone oil-based spinning aid. The polymer solution containing the mixed additives was spun into 44 dtex, 5-filament spandex fiber using a dry spinning process at a take-up speed of 869 meters per minute, and the properties were evaluated.

[0079] The polymer solution of Comparative Example 2 was prepared in a similar manner, but incorporating 0.80% Cyanox® 1790 antioxidant and 0.30% Tinuvin® 234 UV stabilizer, and was prepared as a 44 dtex, 4-filament spandex fiber.

[0080] Many variations and modifications may be made to the above-described embodiments, and all such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.

[0081] In some embodiments, polyester glycol-based polyurethanes contain degradability-enhancing additives, which enhance degradability. Degradability testing is performed according to ASTM D6400, where the compost and plastic mixture is sieved after a set period of time and the amount of material that passes through the sieve is measured to determine disintegration.

[0082] This application can be used regardless of the polymer's intended form, including films, fibers, and solution casting. One or more additives are incorporated via a slurry process, then mixed into the resulting polymer solution. These additives can be present in amounts ranging from 0.1% to 50% by weight of the polymer substrate. The additives not only degrade themselves, but also promote the degradation of the polymer. Benefits offered by the additives include the use of sustainable materials, inherent biodegradation, changes in the polymer's hydrophilicity, and even the promotion of microbial activity on the surface of the base polyester.

[0083] Materials and Equipment Dimethylacetamide (DMAc) is used as a polyester urethane solvent and will therefore be the primary solvent of choice for additives. If the additives are not soluble, they must be properly dispersed.

[0084] Degradability-enhancing additives include cellulosics such as cellulose acetate, cellulose propionate, cellulose butyrate, alkylcelluloses, hypromellose, starch, micro- / nanocrystalline cellulose, cellulose fibrils, alginates, fatty alcohols (such as hexadecanol), and polyvinylpyrrolidone. Various molecular weights / viscosities were investigated.

[0085] Other additives used in processing include antioxidants such as Irganox 245, Irganox 1019, Irganox 1076, Irganox 1098, and silicone spin aids such as Dimethicone 10cS and 100cS.

[0086] The additive slurry is mixed in an overhead agitator equipped with turbine blades and a rotor-stator mixer. The addition of the slurry to the final polymer is also mixed with an overhead mixer and flat disc blades. If particle size reduction is required, a media mill equipped with 0.8-1.0 mm ceramic beads is used.

[0087] Compost inoculum was obtained from a local facility participating in the US Composting Council's Seal of Testing Assurance Program.

[0088] procedure The additive components were mixed in DMAc solvent, formed into a slurry dispersion / solution using a benchtop mixer, and milled to the desired particle size using a media mill, if necessary. This slurry was then mixed with the main polymer solution to the desired content. In early studies, films of the polymer / additive solution were formed to thicknesses of 5 to 40 mils.

[0089] Example Test Method Compostability was determined according to the procedures outlined in ASTM D6400-21, the specification for "Labeling of Plastics Designed to be Aerobically Composted in Municipal or Industrial Facilities." This document references the international standard ISO 20200, "Plastics—Determination of the degree of disintegration of plastic materials under simulated composting conditions in a laboratory-scale test." Film samples were cut into defined 25 mm x 25 mm sections and then placed in a reactor containing the appropriate activated compost. The container was then immersed in a temperature-controlled water bath set at 58 ± 2°C. According to ASTM D6400-21, the total composting time is set at 12 weeks, while ISO 20200 allows for incubation periods of 45 to 90 days. After thermophilic incubation, samples were screened through a 2 mm sieve.

[0090] Material that does not pass through the sieve is considered to be non-disintegrated material. The degree of disintegration (Dis%) is calculated in % using the following formula: During the ceremony, is the initial dry mass of the polymer being incubated is the final dry mass of polymer remaining on the 2 mm screen.

[0091] Molecular weights (Mn and Mw) were analyzed using gel permeation chromatography (GPC) on an Agilent 1100 series analyzer equipped with a diode array detector. Polystyrene standards were run as calibration. Average counts and weights of uncomposted and composted samples were determined. Similar calculations of degradation can be performed for biodegradation: During the ceremony, is the initial n (number) or w (weight) molecular average of the polymer, is the final n (number) or w (weight) molecular average of the polymer after composting.

[0092] Base Slurry A base slurry solution was prepared by mixing 263.29 g of DMAc, 165.28 g of Irganox 245, 66.14 g of 10 cS polydimethylsiloxane, and 255.29 g of a 35% polyether urethane polymer solution, which is used in each formulation of a standard antioxidant and spin aid additive package.

[0093] Biodegradable additive slurry Soluble additives that provide sufficient viscosity when dissolved in DMAc were prepared as follows (by weight): 25% cellulose acetate (CA, grade "CA1"), 12.5% ​​cellulose acetate (CA, grade "CA2"), 30% cellulose acetate propionate (CAP, "CAP1"), 15% cellulose acetate propionate (CAP, "CAP2"), and 35% cellulose acetate butyrate (CAB, "CAB1"). The cellulose acetate composition is 40% acetyl, 3.5% hydroxyl, and 10-200 poise in viscosity range. The cellulose acetate propionate composition is 1-2% acetyl, 40-50% propionyl, 1-3% hydroxyl, and 1-100 poise in viscosity range. The cellulose acetate butyrate content ranges from 2% acetyl content, 50-54% butyryl content, up to 2% hydroxyl content, and a viscosity of 0-2 poise.

[0094] Additional slurries produced were 17.5% hexadecanol (cetyl alcohol) and 25% polyetherurea polymer solution (34.7% solids), 10% media-milled starch and 27% polyetherurea polymer solution (34.7% solids), and 10% media-milled microcrystalline cellulose and 27% polyetherurea polymer solution (34.7% solids). The above slurry formulation was then used to prepare a polymer film. [Table 1]

[0095] The % Loss / Molecular Weight Loss test results for the compositions of Table A are shown in Figures 7-9.

[0096] While what are presently considered to be preferred embodiments of the invention have been described, those skilled in the art will recognize that changes and modifications can be made without departing from the spirit of the invention, and it is intended to include all changes and modifications that come within the true scope of the invention.

Claims

1. 1. A polyurethaneurea fiber comprising a glycol, a diisocyanate, and a chain extender, wherein the glycol component comprises greater than 50% by weight of a polyester glycol having a number average molecular weight of about 450 to about 3300, and the fiber is degradable.

2. 10. The fiber of claim 1, wherein the polyester glycol has a number average molecular weight of about 1000 or greater.

3. The fiber of claim 1 further comprising a second glycol.

4. 2. The fiber of claim 1, wherein the polyester glycol is a copolymer of ethanediol, butanediol, and adipic acid, or 2G / 4G-6.

5. 4. The fiber of claim 3, wherein the glycol is poly(tetramethyl ether) glycol or a mixture of a copolyether glycol and a polyester glycol.

6. 10. The fiber of claim 1, wherein the fiber exhibits a normalized recovery force, expressed as the recovery force at 200% elongation on the fifth unloading cycle, of at least 0.022 centinewtons per decitex.

7. 1. An article of manufacture comprising a polyurethaneurea fiber comprising a glycol, a diisocyanate, and a chain extender, wherein the glycol component comprises greater than 50% by weight of a polyester glycol having a number average molecular weight of from about 450 to about 3300, and wherein the fiber is degradable.

8. The article of claim 7 , wherein the article comprises a fabric or a garment.

9. The article of claim 8 , wherein the fabric is selected from the group consisting of woven fabrics, knitted fabrics, and nonwoven fabrics.

10. 9. The article of claim 8, wherein the garment is selected from the group consisting of sportswear, activewear, formalwear, swimwear, bras, underwear, intimate apparel, tights, outerwear, and shoe fabric.

11. 8. The article of claim 7, wherein the article comprises a stretchable laminate comprising at least a first layer and, optionally, a second layer independently selected from the group consisting of a nonwoven layer, a film, and combinations thereof.

12. 12. The article of claim 11, wherein the stretchable nonwoven laminate has fibers adjacent to or embedded in the laminate.

13. 12. The article of manufacture of claim 11, wherein the article comprises a disposable hygiene article, a disposable diaper, training pants or adult incontinence device or product, a menstrual device or garment or product thereof, a bandage, a wound dressing, a surgical drape, a surgical gown, a surgical mask or other hygienic protective mask, sanitary gloves, a head or face covering, a headband, an ostomy bag, a bed pad or a bed sheet.

14. A composition comprising a glycol component, a diisocyanate, and a chain extender, wherein the glycol component comprises a polyester glycol having a number average molecular weight of from about 450 to about 3300, and a degradability-enhancing additive in an amount of from about 0.1% to about 50% by weight of the composition, wherein the composition is degradable.

15. 15. The composition of claim 14, wherein the polyester glycol comprises greater than about 50% by weight of the glycol component.

16. 15. The composition of claim 14, wherein the composition comprises a form selected from the group consisting of a dispersion, a solution, a film, an extrudate, a foam, and a fiber.

17. 15. The composition of claim 14, wherein the degradability-enhancing additive is selected from the group consisting of cellulose esters (cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate), soluble celluloses (methyl cellulose, ethyl cellulose, hydroxypropyl methyl cellulose), insoluble celluloses (microcrystalline cellulose, nanocrystalline cellulose, cellulose fibrils), polyvinyl alcohol, cetyl alcohol, and starch.

18. 15. The composition of claim 14 further comprising an additional degradability-enhancing additive.

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