POLYESTER-POLYETHER POLYOL, PREPARATION PROCESS AND ITS USE

Abstract

The present application relates to a polyether ester polyol, comprising a repeating structure of formula (1) and a blocking alcohol hydroxyl group, wherein R1 is at least one selected from aromatic rings or aromatic heterocyclic rings, R1 accounts for 4.5%-44% by mass in the repeating structure of formula (1), R2 is at least one selected from saturated alkyl groups having 2-5 carbon atoms, and x is 2-20. The mass percentage of the repeating structure of formula (1) in the polyether ester polyol is greater than 75%. The average functionality of the blocking alcohol hydroxyl group is 1.95-2.00. The number-average molecular weight of the polyether ester polyol is 800-5000. The present application also relates to a preparation method for the polyether ester polyol, and a method for using the polyether ester polyol to prepare polyurethane elastic fibers or a polyurethane elastomer.

Description

1 / 37 POLYESTER-POLYETHER POLYOL, PREPARATION PROCESS AND ITS USE TECHNICAL FIELD OF THE INVENTION

[001] The present invention relates to the field of polyurethane elastomeric fibers (hereinafter referred to as elastomers), more specifically to a polyester-polyether polyol, its method of preparation and its use in the production of polyurethane elastomers. BACKGROUND OF THE TECHNIQUE

[002] Polyurethane is a block copolymer of flexible and rigid segments. The flexible segments are generally composed of flexible polymer chains, obtained by the reaction of polyethers, polyesters, hydroxyl-terminated polybutadiene or other polyols, in combination with polyisocyanates that connect the polyols. The rigid segments are formed by chains with a high capacity for crystallization, obtained by the reaction of polyisocyanates with low molecular weight polyols or with low molecular weight amine-type chain extenders. Both the structure of the flexible and rigid segments directly influence the properties of polyurethane. During the deformation process of polyurethane, the flexible segments are forced to orient themselves internally along the direction of deformation.The flexibility of these segments gives polyurethane a high entropic elasticity during use, providing an intrinsic driving force to spontaneously return to its initial state. Petition 870250089421, dated 10 / 01 / 2025, page 8 / 46 2 / 37 disordered, which guarantees excellent elastic recovery capacity.

[003] Elastane, that is, polyurethane fiber, can have its mechanical properties characterized by multiple parameters, including tensile modulus, recovery modulus, tensile strength at break, tensile strength, stress retention rate, and plastic deformation rate. Among these, the recovery modulus is an important indicator for elastane applications. The recovery modulus refers to the modulus value presented by the polyurethane fiber after undergoing elongation during the recovery process. Fabrics containing elastane require that the fiber possess an adequate recovery modulus so that, after undergoing deformation, the fabric, with the contribution of elastane, can overcome the resistance imposed by the other component fibers and return to its original shape, that is, exhibit a certain capacity for shape retention.In general, the recovery modulus of elastane can be increased by reducing the molar weight of the polyols or by increasing the content of rigid segments. However, both methods increase the rate of plastic deformation after stretching, which means that elastane tends to exhibit permanent deformation, compromising the lifespan of garments that incorporate elastane.

[004] High-performance elastane fibers must combine a high recovery modulus with high resistance to plastic deformation. To this end, the present invention uses as a starting point the materials employed in the preparation of elastomeric fibers. Petition 870250089421, dated 10 / 01 / 2025, page 9 / 46 3 / 37 of polyurethane, seeking to provide a polyester-polyether polyol, and use it in the production of elastomeric polyurethane fibers, unexpectedly obtaining polyurethane fibers that combine high recovery modulus with high resistance to plastic deformation. SUMMARY OF THE INVENTION

[005] Fulfilling this application provides a polyester-polyether polyol, its method of preparation and its use in the production of polyurethane elastomers, as well as polyurethane elastomeric fibers, nonwovens, films or elastomers obtained from it.

[006] The polyester-polyether polyol of the present application comprises a repeating structure of Formula (1) and terminal hydroxyl groups: OO Γ II II zλ1 — C-R1-C-O4 R2-Oj-X Formula (1) in which Ri is selected from at least one aromatic or heteroaromatic ring, and the mass content of Ri in the repeating structure of Formula (1) varies from 4.5% to 44%; R2 is selected from at least one saturated alkyl group with 2 to 5 carbon atoms; x varies from 2 to 20;

[007] The repetitive structure of Formula (1) represents more than 75% by weight of the polyesterpolyether polyol;

[008] The average functionality of the terminal hydroxyl groups is 1.95 to 2.00;

[009] The number average molecular weight of polyester-polyether polyol is in the range of 800 to 5,000. Petition 870250089421, dated 10 / 01 / 2025, p. 10 / 46 4 / 37

[010] In one embodiment, the melting point of the polyester-polyether polyol is below 80 °C, being preferably liquid at room temperature. In another embodiment, the polyester-polyether polyol has a viscosity of less than 500 Poise at 90 °C and under a shear rate of 1 s-1.

[011] In one embodiment, the polyether diol has a number average molecular weight of 100 to 1,000, it being preferable that the polyether diol has a degree of polymerization of 2 to 20, more preferably 3 to 10.

[012] In one embodiment, polyether diol is a copolymer obtained from the reaction of at least two of the following substances: tetrahydrofuran, ethylene oxide, propylene oxide, 2-methyltetrahydrofuran or 3-methyltetrahydrofuran.

[013] In another embodiment, polyether diol is a mixture of at least two of the following substances: polytramethylene glycol, polypropylene glycol, or polyethylene glycol.

[014] The method for preparing the polyester polyether polyol according to the present application may include the reaction of an aromatic dicarboxylic acid, its ester or its anhydride with the polyether diol, wherein aromatic refers to substances containing an aromatic or heteroaromatic ring in their molecular structure. In one embodiment, the aromatic dicarboxylic acid is selected alone or in combination with two or more of terephthalic acid, isophthalic acid, phthalic acid, 4,4'-biphenyldicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid and naphthalene-2,3-dicarboxylic acid. Petition 870250089421, dated 10 / 01 / 2025, p. 11 / 46 5 / 37 dicarboxylic acid, 2,5-furanodicarboxylic acid, p-phenylenediacetic acid, m-phenylenediacetic acid or p-phenylenediacetic acid, preferably the respective ester is obtained by reacting the aromatic dicarboxylic acid with a monoalcohol with a boiling point below 150 °C.

[015] In another embodiment, the polyether diol has a number average molecular weight of 100 to 1,000, it being preferable that the degree of polymerization of the polyether diol be between 2 and 20, and more preferably between 3 and 10.

[016] The present embodiment also provides a method for preparing polyurethane elastomeric fibers, nonwovens, films or elastomers, using the polyester-polyether polyol described in the invention as raw material, as well as the polyurethane fibers, nonwovens, films or elastomers obtained from this method.

[017] In a specific embodiment, polyurethane elastomeric fibers, nonwovens, films or elastomers are prepared by solution processing or by melt processing. Beneficial Effects:

[018] The polyester-polyether polyol provided by the present invention allows the resulting polyurethane elastomeric fibers to exhibit a high recovery modulus and, at the same time, a low rate of plastic deformation, improving the shape retention capacity and service life of fabrics containing elastane. Furthermore, the use of a polyether diol blend allows adjusting the properties of the elastane according to the requirements. Petition 870250089421, dated 10 / 01 / 2025, p. 12 / 46 6 / 37 DETAILED DESCRIPTION OF THE INVENTION

[019] Currently, the most common method for producing polyurethane elastomeric fibers uses polyether diol as a feedstock, especially polytetramethylene glycol diol. This is first reacted with a diisocyanate to form a prepolymer, which is then chain-extended in the presence of chain extenders and a terminator. In conventional technologies, increasing the recovery modulus generally results in an increase in the plastic deformation rate. However, inventors have unexpectedly discovered a polyester-polyether polyol that, when used as a feedstock for the production of polyurethane elastomeric fibers, provides fibers that exhibit not only a higher recovery modulus but also a lower plastic deformation rate.

[020] Specifically, the present invention provides a polyester-polyether polyol, comprising a repeating structure of Formula (1) and hydroxyl termination: OO Γ II II zλΊ — C-Ri-C-O4 R2-Oj-X Formula (1), wherein Ri is selected from at least one aromatic ring or heteroaromatic ring, the mass content of Ri in the repeating units of Formula (1) varying from 4.5% to 44%. R2 is selected from at least one saturated alkyl group containing 2 to 5 carbon atoms, preferably R2 is selected from at least two saturated alkyl groups containing 2 to 5 carbon atoms. Petition 870250089421, dated 10 / 01 / 2025, page 13 / 46 7 / 37 carbon. x varies from 2 to 20. The repeating structure of Formula (1) represents more than 75% by mass of the polyester-polyether polyol. When the content of Ri aromatic groups in the polyester-polyether polyol is too high, it can make the polyester-polyether polyol excessively rigid, resulting in high viscosity, which is unfavorable for the production process of polyurethane fibers. On the other hand, when the content of Ri aromatic groups in this polyester-polyether polyol is too low, the effect of increasing the recovery modulus of polyurethane fibers will not be achieved.

[021] The aromatic ring may be selected from at least one of benzene ring, naphthalene ring, anthracene ring or phenanthrene ring. The heteroaromatic ring may be selected from at least one of pyridine, furans, thiazole or pyrimidine. In an optional embodiment, in addition to the aromatic or heteroaromatic ring, Ri may also include 1 to 4 methylene groups.

[022] In a preferred embodiment, the polyester-polyether polyol of the present invention has a linear overall structure, in which the polyether structure and aromatic rings are arranged alternately, thus increasing the resistance to plastic deformation of the polyurethane fibers. At the same time, the introduction of aromatic or heteroaromatic rings gives the polyurethane fibers a higher modulus of elasticity. In another preferred embodiment, the repeating units shown in Formula (1) represent more than 95% of the mass of the polyester-polyether polyol. In another preferred embodiment, the polyester-polyether polyol of the present invention Petition 870250089421, dated 10 / 01 / 2025, p. 14 / 46 8 / 37 consists exclusively of the repeating structure of Formula (1) and the hydroxyl termination.

[023] According to the present invention, the average functionality of the terminal hydroxyl groups of the polyester-polyether polyol can vary from 1.95 to 2.00, preferably 1.96 to 2.00, and more preferably 1.98 to 2.00. This ensures that the polyester-polyether polyol can be efficiently reactive with diisocyanates to form terminations, subsequently undergoing chain extension by means of small amine or alcohol molecules. When the average functionality is greater than 2.00, the use of the polyester-polyether polyol as a raw material for the production of polyurethane may result in the formation of cross-linked structures, preventing the formation of linear chain polyurethane. Such polyurethane tends to form gels during continuous production, hindering the continuity of the process. On the other hand, if the average functionality is too low, the polyurethane obtained will have reduced molecular mass, impairing the properties of the polyurethane fibers.In practice, during the reaction, the polyether diol can undergo dehydration of the terminal hydroxyl groups, forming double bonds, and, due to limitations in the reaction efficiency, the condensation or transesterification to form the polyester-polyether polyol is not 100% complete, resulting in an average functionality generally lower than 2.00.

[024] Here, “average functionality” refers to the average number of moles of reactive terminal hydroxyl groups per mole of polyester-polyether polyol. In the present invention, considering the possible formation of double bonds by Petition 870250089421, dated 10 / 01 / 2025, p. 15 / 46 9 / 37 dehydration of the hydroxyl groups of the polyetherdiol, as well as the presence of unreacted carboxyl groups, the average functionality of the hydroxyl groups can be calculated using the following formula:

[025] Functionality = 2 x moles of hydroxyl / (moles of hydroxyl + moles of carboxyl + moles of double bonds).

[026] The number-average molecular weight of the polyester-polyether polyol of the present invention can vary from 800 to 5,000, preferably from 1,000 to 3,500, more preferably from 1,400 to 2,500, and even more preferably from 1,500 to 2,300. The higher the number-average molecular weight of the polyester-polyether polyol, the higher its viscosity, which hinders continuous operations on an industrial scale. However, if the molecular weight of the polyester-polyether polyol is too low, in order for the molecular weight of the polyurethane prepolymer formed in the polymerization reaction to be consistent, a greater amount of diisocyanate will be required, resulting in a high content of urethane groups in the prepolymer. This increases the intermolecular interactions between the prepolymer molecules, increasing its viscosity.Furthermore, in this case, the length of the flexible segments in the formed polyurethane will be reduced, negatively impacting the recovery performance of the polyurethane elastomeric fibers.

[027] In a preferred embodiment, the polyester-polyether polyol of the present invention has a viscosity of less than 500 Poise at 90 °C and under a rate of Petition 870250089421, dated 10 / 01 / 2025, page 16 / 46 10 / 37 shear stress of 1 s-1, preferably less than 200 Poise.

[028] The polyester-polyether polyol of the present invention has a melting point below 80 °C, and it is preferable that the liquid be at room temperature, avoiding its solidification during storage or transport, ensuring the feasibility of continuous operations on an industrial scale. Otherwise, it would be necessary to heat it to promote its melting, which would increase energy consumption.

[029] The present invention also provides a method for preparing the polyester-polyether polyol, which comprises the condensation or transesterification reaction of an aromatic dicarboxylic acid, its ester or its anhydride with a polyether diol.

[030] According to the method of the present invention, the aromatic dicarboxylic acid is selected alone or in combination with two or more of the following: terephthalic acid, isophthalic acid, phthalic acid, 4,4'-biphenyldicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid and naphthalene-2,3-dicarboxylic acid, 2,5-furanedicarboxylic acid, p-phenylenediacetic acid, m-phenylenediacetic acid or p-phenylenediacetic acid. In one embodiment, the respective ester can be obtained by reacting the aromatic dicarboxylic acid with a low molecular weight monoalcohol, such as methanol, ethanol, n-butanol or n-hexanol, with a boiling point below 150 °C, allowing such alcohols to be easily removed by distillation in subsequent esterification or transesterification reactions; Petition 870250089421, dated 10 / 01 / 2025, p. 17 / 46 11 / 37 Preferably, the monoalcohol is methanol or ethanol. Furthermore, compared to aromatic dicarboxylic acid, the respective esters allow the transesterification reaction with polyether diol to occur under milder conditions, which favors the design of the production process. The aromatic dicarboxylic acid used can be derived from recycled plastics, allowing for the reuse of waste, reducing the production costs of polyurethane elastomeric fibers and meeting the requirements of a green economy.

[031] According to the method of the present invention, the polyether diol has a degree of polymerization preferably of 2 to 20, more preferably of 3 to 10. The number average molecular weight of the polyether diol can vary from 100 to 1,000, preferably from 300 to 1,000, more preferably from 600 to 900. In fact, only when the degree of polymerization and the number average molecular weight of the polyether diol are within the above ranges can the resulting structure, in which the polyether segments are arranged alternately with the aromatic rings, ensure that the resulting polyester-polyether polyol, when used in the preparation of polyurethanes, simultaneously provides an increase in the modulus of elasticity of the elastomeric polyurethane fibers and greater resistance to plastic deformation. If the molecular weight of the polyether diol is too low, the viscosity of the resulting polyester-polyether polyol will be excessive, hindering the continuation of the process.On the other hand, if the molecular weight of the polyether diol is too high, it will not have a significant effect on increasing the recovery modulus of polyurethane fibers. Petition 870250089421, dated 10 / 01 / 2025, page 18 / 46 12 / 37 Polyether diols can be obtained by ring-opening polymerization of epoxy monomers or by polycondensation of low molecular weight diols; they can be homopolymers synthesized from a single monomer or copolymers synthesized from two or more monomers. For example, a suitable polyether diol for the present invention could be polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, polytetramethylene glycol, or a diol copolymer obtained by reacting tetrahydrofuran with monomers such as ethylene oxide, propylene oxide, 2-methyltetrahydrofuran, or 3-methyltetrahydrofuran.

[032] From the point of view of the synthesis process, the production routes for polyethylene glycol and polypropylene glycol are relatively short, resulting in lower production costs and product prices. The partial incorporation of polyethylene glycol and polypropylene glycol as raw materials into polytetramethylene glycol contributes to cost reduction. Furthermore, compared to polytetramethylene glycol, polyethylene glycol and polypropylene glycol exhibit a higher density of ether-oxygen bonds, intensifying the interactions between the flexible and rigid segments, increasing the tensile modulus and the recovery modulus, although this is unfavorable to elongation. On the other hand, the greater the number of carbon atoms between the ether-oxygen bonds, the weaker the interaction between the flexible and rigid segments of the polyurethane, resulting in greater elongation of the polyurethane prepared from polyester-polyether diol, with lower tensile stress and Petition 870250089421, dated 10 / 01 / 2025, page 19 / 46 13 / 37 recovery stress. Therefore, in practical production, it is preferable to use a mixture of polyether diols, allowing for cost reduction while simultaneously adjusting product properties. For example, a mixture of at least two polytramethylene glycol, polypropylene glycol, and polyethylene glycol can be used, or a diol copolymer obtained by reacting at least two monomers between tetrahydrofuran, ethylene oxide, propylene oxide, 2-methyltetrahydrofuran, or 3-methyltetrahydrofuran, preferably a diol copolymer obtained by reacting tetrahydrofuran with at least one of ethylene oxide, propylene oxide, 2-methyltetrahydrofuran, or 3-methyltetrahydrofuran.

[033] Optionally, according to the method of the present invention, in the reaction between the aromatic dicarboxylic acid, its ester or its anhydride and the polyether diol, low molecular weight diols or aliphatic dicarboxylic acids may be added in order to reduce costs or partially modify the polyester-polyether polyol. In this case, the amount of low molecular weight diol must be strictly controlled, as excessive introduction can significantly increase the viscosity of the resulting polyester-polyether polyol, hindering subsequent termination reactions with isocyanates and chain extension. Preferably, the amount of low molecular weight diol should be less than 50% by mass of the polyether diol, more preferably less than 20%. The low molecular weight diol has a molecular weight of less than 200 and may include one or more of ethylene glycol, propylene glycol or butanediol. Petition 870250089421, dated 10 / 01 / 2025, p. 20 / 46 14 / 37

[034] The polyester-polyether polyol of the present invention can be prepared by vacuum esterification or by transesterification, generally carried out in two steps.

[035] In the first stage of the aromatic dicarboxylic acid esterification process, the process can be carried out under a nitrogen atmosphere, at ambient pressure, at a temperature of 150 to 230 °C. The reaction temperature can be gradually increased, with the heating process controlled by a PID (proportional-integral-derivative) controller. The completion of the first stage of the reaction is indicated when the system reaches a homogeneous state, indicating that the aromatic dicarboxylic acid, initially present in suspension due to its insolubility, has been completely reacted. At this point, the water efflux rate from the system reaches 90% or more, with the water efflux rate defined as: water efflux rate = amount of water released / (moles of dicarboxylic acid χ 36).

[036] After the completion of the first esterification stage, the second stage begins. In this stage, a catalyst such as tetraisopropyl titanate, tetrabutyl titanate, tin oxide, or antimony oxide can be added to the system. The amount of catalyst can vary from 10 to 500 ppm (based on the amount of the final polyester-polyether polyol). This catalyst exhibits significant activity in catalyzing esterification or transesterification, facilitating the reduction of the system's acidity index. The reaction temperature in the second stage can vary from 225 to 250 °C. During the process, the index Petition 870250089421, dated 10 / 01 / 2025, page 21 / 46 15 / 37 The acidity of the system is continuously monitored using an acidity measuring instrument until the acidity index reaches the desired value (usually 0.5 mg KOH / g). When this value is reached, the second stage of the reaction is considered complete, heating is stopped, and the material is discharged after the system temperature decreases to a suitable value, usually below 90 °C.

[037] The ratio between aromatic dicarboxylic acid and polyether diol can be determined based on the desired molecular weight of the polyester-polyether polyol and the type of aromatic dicarboxylic acid used, with the hydroxyl groups of the polyether diol being in excess relative to the reactive groups of the aromatic dicarboxylic acid. For a given combination of polyether diol and aromatic dicarboxylic acid, the greater the amount of polyether diol used, the lower the molecular weight of the resulting polyester-polyether polyol.

[038] The present invention also provides a method for using polyurethane products, such as polyurethane elastomeric fibers, nonwovens, films or elastomers, using as raw material the described polyester-polyether polyol or the polyester-polyether polyol obtained by the described method. The method for preparing the polyurethane can be carried out by a two-step process, involving the synthesis of a prepolymer, or by a one-step process, in which all components are added simultaneously (single-container method).

[039] The method for preparing polyurethane comprises the following two steps: (1) Reacting the polyol Petition 870250089421, dated 10 / 01 / 2025, p. 22 / 46 16 / 37 polyester-polyether with a diisocyanate to form a prepolymer; and (2) Polymerizing said prepolymer with a chain extender and a chain terminator. The one-step method for preparing polyurethane (one-vessel method) comprises: (1) Adding the polyester-polyether polyol, the diisocyanate, and a low molecular weight diol-type chain extender to a reaction vessel; (2) Mixing the materials in the reaction vessel and heating to promote the reaction, or heating during the mixing process to carry out the reaction. The diisocyanate may be selected from at least one of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and their isomers. The chain extender may be an amine-type or alcohol-type chain extender.The amine-type chain extender may be a diamine with 2 to 30 carbon atoms, selected from at least one of ethylenediamine, propylenediamine, pentamethylenediamine, methylpentamethylenediamine, methylpropylenediamine, hexamethylenediamine, triethylenediamine, xylenediamine, phenylenediamine, diaminocyclohexane, hexamethylenediamine, or dopamine. The alcohol-type chain extender may be selected from at least one of ethylene glycol, 1,4-butanediol, diethylene glycol, 1,6-hexanediol, 1,3-propanediol, or 1,4-dihydroxymethylcyclohexane. The terminating agent may be a monoamine with 2 to 20 carbon atoms, selected from at least one of ethylamine, isopropylamine, n-butylamine, tert-butylamine, hexylamine, dimethylamine, diethylamine, dipropylamine, di-n-butylamine. Petition 870250089421, dated 10 / 01 / 2025, page 23 / 46 17 / 37 di-tert-butylamine, diisobutylamine, diisopropylamine, cyclohexylamine or ethanolamine.

[040] Unless otherwise indicated in this document, the corresponding operating conditions of existing methods of using polyether-diol for the preparation of polyurethane products, such as polyurethane elastomeric fibers, nonwovens, films and elastomers — including solution or melt processing methods — can be applied in the present invention. For example, polyurethane elastomeric fibers can be produced by dry spinning of polyurethane solution, as described in patent document CN1147628C, or by melt spinning of polyurethane flakes, as described in the melt spinning method described in patent document CN1180137C.Nonwovens can be processed by methods such as meltblown or solution electrospinning, as detailed in the meltblown nonwoven manufacturing method in patent document CN101400838A or the solution electrospinning method in patent document JP2009108422A for the preparation of nonwovens. Polyurethane films can be processed by methods such as solution scrape coating, dipping, melt extrusion, film blowing, or casting, as described in the scrape coating method in the patent document. JP2005205787A, in the immersion method in the patent document WO2015064776A1, in the extrusion method in patent document GB1137520A, in the film blowing method in patent document DE2239478A1 and in the casting method in patent document JP2004203933A. Elastomers can Petition 870250089421, dated 10 / 01 / 2025, page 24 / 46 18 / 37 can be processed by methods such as extrusion, injection or casting, as described in the extrusion methods in patent document JP1996027376A, in the injection method of patent document US3917792A and in the casting method in patent document CA1251294A. The methods for producing polyurethane products described in the aforementioned patent documents are incorporated into the present invention. The exemplified methods for preparing polyurethane elastomeric fibers, nonwovens, films and elastomers mentioned above are only examples. In addition to the forms mentioned, the polyester-polyether polyol of the present invention can be used as a diol feedstock for the production of polyurethane products by any technique or process already known. Examples of Achievement

[041] The present invention is described in greater detail below by means of embodiments, in which the test methods for the parameters involved are specifically as follows:

[042] 1. Average Functionality:

[043] Functionality = 2 χ (moles of hydroxyl) / (moles of hydroxyl + moles of carboxyl + moles of double bonds).

[044] The acid value is determined according to the method described in HG / T 2708-1995; the hydroxyl value is determined according to the method described in HG / T 2709-1995; the degree of unsaturation is determined according to the method described in GB / T 12008.6-2010. The values ​​of acid value, hydroxyl value and degree of unsaturation are Petition 870250089421, dated 10 / 01 / 2025, page 25 / 46 19 / 37 converted into the number of moles of the respective terminal groups present in the polyether-ester diol.

[045] 2. Tensile Strength at 300%, Tensile Strength and Elongation at Break: All determined according to the Textile Industry Standard of the People's Republic of China FZ / T 50006-2013, Test Method for Tensile Properties of Elastane Yarns.

[046] 3. Plastic Deformation Test:

[047] The prepared sample is fixed at one end in the upper clamping device and subjected to a pre-tension at the other end, stretching the sample axially and fixing it in the lower clamp, and the equipment is then activated.

[048] The sample is stretched from 0% (L0) to 300% (L1) elongation at a speed of 500 mm / min, and then returned to 0% elongation. This stretching and recovery cycle is repeated four times. In the fifth stretching cycle at 300%, the value of force F1 corresponding to the 200% elongation is recorded. After a 30-second pause, the sample returns to 0% elongation, and the value of force F2 is recorded at the 200% return point. After another 30-second pause, the sixth stretching is performed, recording the length L2 of the sample at the pre-tension point.

[049] Formula for calculating the rate of plastic deformation: (L2 - L0) / L0 x 100%

[050] In this formula, 5LP200% represents the tensile stress at 200% in the fifth cycle, that is, F1. 5UP200% represents the recovery stress at 200% in the fifth cycle of return from 300% to 200% elongation, or Petition 870250089421, dated 10 / 01 / 2025, page 26 / 46 20 / 37, or F2, which can be used to characterize the recovery modulus. The plastic deformation rate represents the percentage increase in the length of the elastane yarn relative to the original length after five stretching cycles. 5UP200% / 5LP200% represents the ratio between the 200% recovery stress and the 200% tensile stress in the fifth cycle of the test.

[051] In addition, the antioxidants mentioned in the following examples are antioxidant 245, the tinting aids are DH300R or 2462B, and the light stabilizers are Tinuvin 791, all commercially available.

[052] Example 1: Preparation of a polyether ester diol with a number average molecular weight of 1,500

[053] 17 parts by weight of PEG600 polyethylene glycol (number average molecular weight of 600) and 2.7 parts by weight of terephthalic acid were added to a reactor. Nitrogen was introduced to replace the air inside the reactor. Stirring was started at 150 rpm. The system was heated in a programmed manner, raising the temperature to 150 °C and maintaining it for 5 hours; then, the temperature was raised to 230 °C, maintaining it until the water exit rate from the system reached 90% or more of the theoretical value, and the solution became homogeneous. At this point, tetraisopropyl titanate catalyst was added and vacuum was gradually applied until the pressure reached 2,000 Pa. The process continued until the acidity index was less than 0.5 mg KOH / g, obtaining a polyether ester diol with a number average molecular weight of 1,500. Tests showed that the average functionality was 1.98, the viscosity at 90 °C and under a shear rate of 1 s-1 Petition 870250089421, dated 10 / 01 / 2025, page 27 / 46 21 / 37 was 20 Poise, and the material remained liquid at room temperature.

[054] Example 2: Use of the polyether-ester diol from Example 1 in the preparation of polyurethane elastomeric fibers

[055] 100 kg of the polyether ester diol prepared in Example 1 were added to a reactor previously heated to 45 °C. Stirring was started at a speed of 150 rpm, and then 26.5 kg of diphenylmethane diisocyanate were added. After 5 minutes of stirring, the temperature of the mixture was raised to 90 °C and maintained for 2 hours, forming the prepolymer.

[056] The prepolymer was cooled to 50 °C and dissolved in 161 kg of dimethylacetamide (DMAc). Subsequently, an amine solution with a mass concentration of 3.2%, containing 2.33 kg of ethylenediamine (EDA) and 0.28 kg of diethylamine (DEA), was added, and the stirring speed was increased to 300 rpm, promoting the chain extension reaction. After the chain extension reaction was complete, the necessary additives, such as antioxidants and dyeing aids, were added. The mixture was then subjected to a maturation process for 30 hours, obtaining a spinning solution with a solids content of 35%. This solution was used in a dry spinning process, resulting in PUU-1 elastomeric polyurethane fibers with a denier of 40D.

[057] Example 3: Preparation of a polyether ester diol with a number average molecular weight of 2.120

[058] 17 parts by weight of PEG600 polyethylene glycol (number average molecular weight of) were added. Petition 870250089421, dated 10 / 01 / 2025, p. 28 / 46 22 / 37 600) and 3.2 parts by weight of terephthalic acid were added to a reactor. Nitrogen was introduced to replace the air inside the reactor. Stirring was started at 150 rpm. The system was heated in a programmed manner, raising the temperature to 150 °C and maintaining it for 5 hours; then the temperature was raised to 230 °C, maintaining it until the water exit rate from the system reached 90% or more of the theoretical value, and the solution became homogeneous. At this point, tetraisopropyl titanate catalyst was added and vacuum was gradually applied until the pressure reached 2,000 Pa. The process continued until the acidity index was less than 0.5 mg KOH / g, obtaining a polyether ester diol with a number-average molecular weight of 2,120. Tests showed that the average functionality was 1.98, the viscosity at 90 °C and under a shear rate of 1 s-1 was 25 Poise, and the material remained liquid at room temperature.

[059] Example 4: Use of the polyether-ester diol from Example 3 for the preparation of polyurethane elastomeric fibers

[060] 100 kg of the polyether ester diol prepared in Example 3 were added to a reactor previously heated to 45 °C. Stirring was started at a speed of 150 rpm, and then 21.3 kg of diphenylmethane diisocyanate were added. After 5 minutes of stirring, the temperature of the mixture was raised to 90 °C and maintained for 2 hours, forming the prepolymer.

[061] The prepolymer was cooled to 50 °C and dissolved in 154.4 kg of dimethylacetamide (DMAc). Subsequently, an amine solution was added with Petition 870250089421, dated 10 / 01 / 2025, page 29 / 46 23 / 37 A mass concentration of 3%, containing 2.25 kg of ethylenediamine (EDA) and 0.28 kg of diethylamine (DEA), was used, and the stirring speed was increased to 300 rpm, promoting the chain extension reaction. After the chain extension reaction was complete, the necessary additives, such as antioxidants and dyeing aids, were added. The mixture was then subjected to a maturation process for 30 hours, obtaining a spinning solution with a solids content of 35%. This solution was used in a dry spinning process, resulting in PUU-2 elastomeric polyurethane fibers with a denier of 40D.

[062] Example 5: Preparation of a polyether ester diol with a number average molecular weight of 1800

[063] 8.5 parts by weight of polytetramethylene glycol PTG650 (number average molecular weight of 650), 8.5 parts by weight of polyethylene glycol PEG600 (number average molecular weight of 600), and 3.52 parts by weight of terephthalic acid were added to a reactor. Nitrogen was introduced to replace the air inside the reactor. Stirring was started at 150 rpm. The system was heated in a programmed manner, raising the temperature to 150 °C and maintaining it for 5 hours; then, the temperature was raised to 230 °C, maintaining it until the water output rate from the system reached 90% or more of the theoretical value, and the solution became homogeneous. At this point, tetraisopropyl titanate catalyst was added and vacuum was gradually applied until the pressure reached 2,000 Pa. The process continued until the acidity index was less than 0.5 mg KOH / g, obtaining a polyether ester diol with a number-average molecular weight of 1,800. Tests demonstrated that... Petition 870250089421, dated 10 / 01 / 2025, pp. 30 / 46 The average functionality of 24 / 37 was 1.98, the viscosity at 90 °C and under a shear rate of 1 s-1 was 45 Poise, and the material remained liquid at room temperature.

[064] Example 6: Use of the polyether-ester diol from Example 5 for the preparation of polyurethane elastomeric fibers

[065] 100 kg of the polyether ester diol prepared in Example 5 were added to a reactor previously heated to 45 °C. Stirring was started at a rate of 150 rpm, and then 23.5 kg of diphenylmethane diisocyanate were added. After 5 minutes of stirring, the temperature of the mixture was raised to 90 °C and maintained for 2 hours, forming the prepolymer.

[066] The prepolymer was cooled to 50 °C and dissolved in 157 kg of dimethylacetamide (DMAc). Subsequently, an amine solution with a mass concentration of 3.2%, containing 2.27 kg of ethylenediamine (EDA) and 0.28 kg of diethylamine (DEA), was added, and the stirring speed was increased to 300 rpm, promoting the chain extension reaction. After the chain extension reaction was complete, the necessary additives, such as antioxidants and dyeing aids, were added. The mixture was then subjected to a maturation process for 30 hours, obtaining a spinning solution with a solids content of 35%. This solution was used in a dry spinning process, resulting in PUU-3 elastomeric polyurethane fibers with a denier of 40D.

[067] Example 7: Preparation of a polyether ester diol with a number average molecular weight of 1.850 Petition 870250089421, dated 10 / 01 / 2025, page 31 / 46 25 / 37

[068] 17 parts by weight of polytramethylene glycol PTG650 (number average molecular weight of 650) and 3.36 parts by weight of terephthalic acid were added to a reactor. Nitrogen was introduced to replace the air inside the reactor. Stirring was started at 150 rpm. The system was heated in a programmed manner, raising the temperature to 150 °C and maintaining it for 5 hours. Then, the temperature was raised to 230 °C, maintaining it until the water output rate from the system reached 90% or more of the theoretical value, and the solution became homogeneous. At this point, tetraisopropyl titanate catalyst was added and vacuum was gradually applied until the pressure reached 2,000 Pa. The process continued until the acidity index was less than 0.5 mg KOH / g, obtaining a polyether ester diol with a number average molecular weight of 1,850.Tests showed that the average functionality was 1.98, the viscosity at 90 °C and under a shear rate of 1 s-1 was 38 Poise, and the material remained liquid at room temperature.

[069] Example 8: Use of the polyether-ester diol from Example 7 for the preparation of polyurethane elastomeric fibers

[070] 100 kg of the polyether ester diol prepared in Example 7 were added to a reactor previously heated to 45 °C. Stirring was started at a rate of 150 rpm, and then 23.1 kg of diphenylmethane diisocyanate were added. After 5 minutes of stirring, the temperature of the mixture was raised to 90 °C and maintained for 2 hours, forming the prepolymer. Petition 870250089421, dated 10 / 01 / 2025, pp. 32 / 46 26 / 37

[071] The prepolymer was cooled to 50 °C and dissolved in 157 kg of dimethylacetamide (DMAc). Subsequently, an amine solution with a mass concentration of 3.2%, containing 2.26 kg of ethylenediamine (EDA) and 0.27 kg of diethylamine (DEA), was added, and the stirring speed was increased to 300 rpm, promoting the chain extension reaction. After the chain extension reaction was complete, the necessary additives, such as antioxidants and dyeing aids, were added. The mixture was then subjected to a maturation process for 30 hours, obtaining a spinning solution with a solids content of 35%. This solution was used in a dry spinning process, resulting in PUU-4 elastomeric polyurethane fibers with a denier of 40D.

[072] Example 9: Preparation of a polyether ester diol with a number average molecular weight of 4,700

[073] 17 parts by weight of PEG600 polyethylene glycol (number average molecular weight of 600) and 4.1 parts by weight of terephthalic acid were added to a reactor. Nitrogen was introduced to replace the air inside the reactor. Stirring was started at 150 rpm. The system was heated in a programmed manner, raising the temperature to 150 °C and maintaining it for 5 hours. Then, the temperature was raised to 230 °C, maintaining it until the water exit rate from the system reached 90% or more of the theoretical value, and the solution became homogeneous. At this point, tetraisopropyl titanate catalyst was added and vacuum was gradually applied until the pressure reached 2,000 Pa. The process continued until the acidity index was less than 0.5 mg KOH / g, obtaining a polyether ester diol with Petition 870250089421, dated 10 / 01 / 2025, pp. 33 / 46 27 / 37 number average molecular weight of 4,700. Tests showed that the average functionality was 1.96, the viscosity at 90 °C and under a shear rate of 1 s-1 was 60 Poise, and the material remained liquid at room temperature.

[074] Example 10: Use of the polyether-ester diol from Example 9 for the preparation of polyurethane elastomeric fibers

[075] 100 kg of the polyether ester diol prepared in Example 9 were added to a reactor previously heated to 45 °C. Stirring was started at a rate of 150 rpm, and then 14.3 kg of diphenylmethane diisocyanate were added. After 5 minutes of stirring, the temperature of the mixture was raised to 90 °C and maintained for 2 hours, forming the prepolymer.

[076] The prepolymer was cooled to 50 °C and dissolved in 145.5 kg of dimethylacetamide (DMAc). Subsequently, an amine solution with a mass concentration of 3.2%, containing 2.12 kg of ethylenediamine (EDA) and 0.26 kg of diethylamine (DEA), was added, and the stirring speed was increased to 300 rpm, promoting the chain extension reaction. After the chain extension reaction was complete, the necessary additives, such as antioxidants and dyeing aids, were added. The mixture was then subjected to a maturation process for 30 hours, obtaining a spinning solution with a solids content of 35%. This solution was used in a dry spinning process, resulting in PUU-5 elastomeric polyurethane fibers with a denier of 40D. Petition 870250089421, dated 10 / 01 / 2025, pages 34 / 46 28 / 37

[077] Comparative Example 1: Use of polytetramethylene glycol (PTMG) with a number average molecular weight of 2,000 for the preparation of polyurethane elastomeric fibers

[078] 100 kg of polytramethylene glycol PTMG2000 (number average molecular weight of 2000) were added to a reactor previously heated to 45 °C. Stirring was started at a speed of 150 rpm, and then 22.2 kg of diphenylmethane diisocyanate were added. After 5 minutes of stirring, the mixture was heated to 90 °C and held at that temperature for 2 hours, forming the prepolymer.

[079] The prepolymer was cooled to 50 °C and dissolved in 155.5 kg of dimethylacetamide (DMAc). Subsequently, an amine solution with a mass concentration of 3.2%, containing 2.26 kg of ethylenediamine (EDA) and 0.28 kg of diethylamine (DEA), was added, and the stirring speed was increased to 300 rpm, promoting the chain extension reaction. After the chain extension reaction was complete, the necessary additives, such as antioxidants and dyeing aids, were added. The mixture was then subjected to a maturation process for 30 hours, obtaining a spinning solution with a solids content of 35%. This solution was used in a dry spinning process, resulting in PUU-0 elastomeric polyurethane fibers with a denier of 40D.

[080] Example 11: Preparation of a polyether ester diol with a number average molecular weight of 3.140

[081] 17 parts by weight of PEG600 polyethylene glycol (number average molecular weight of) were added Petition 870250089421, dated 10 / 01 / 2025, pp. 35 / 46 29 / 37 A solution of 600 mg KOH and 3.7 parts by weight of naphthalenedicarboxylic acid was placed in a reactor. Nitrogen was introduced to replace the air inside the reactor. Stirring was started at 150 rpm. The system was heated in a programmed manner to 150 °C and maintained at this temperature for 5 hours. Then, the temperature was raised to 230 °C, maintaining it until the water output rate reached 90% or more of the theoretical value, and the solution became homogeneous. At this point, tetraisopropyl titanate catalyst was added and vacuum was gradually applied to 2,000 Pa. The process continued until the acidity index was less than 0.5 mg KOH / g, obtaining a naphthalene ring polyether ester diol with a number average molecular weight of 3140. Tests showed that the average functionality was 1.97, the viscosity at 90 °C and under a shear rate of 1 s-1 was 80 Poise, and the material remained liquid at room temperature.

[082] Example 12: Preparation of a polyether-ester diol with a number average molecular weight of 3,250.

[083] 17 parts by weight of PEG1000 polyethylene glycol (number average molecular weight of 1000) and 1.9 parts by weight of naphthalenedicarboxylic acid were added to a reactor. Nitrogen was introduced to replace the air inside the reactor. Stirring was started at 150 rpm. The system was programmed to be heated to 150 °C and held at that temperature for 5 hours. Then, the temperature was raised to 235 °C and maintained until the solution became homogeneous and transparent. At this point, tetraisopropyl titanate catalyst was added and vacuum was gradually applied. Petition 870250089421, dated 10 / 01 / 2025, pages 36 / 46 30 / 37 up to 2,000 Pa. The process continued until the acidity index was less than 0.5 mg KOH / g, obtaining a naphthalene ring polyether ester diol with a number average molecular weight of 3,250. Tests showed that the average functionality was 1.99, the viscosity at 90 °C and under a shear rate of 1 s⁻¹ was 40 Poise, and the melting point was 32.1 °C.

[084] Example 13: Preparation of a polyether ester diol with a number average molecular weight of 3,500

[085] 17 parts by weight of polypropylene glycol 1,3 PPG950 (number average molecular weight of 950) and 2.1 parts by weight of terephthalic acid were added to a reactor. Nitrogen was introduced to replace the air inside the reactor. Stirring was started at 150 rpm. The system was heated in a programmed manner to 150 °C, maintaining this condition for 5 hours. Then, the temperature was raised to 235 °C, maintaining it until the system became a homogeneous and transparent solution. At this point, tetraisopropyl titanate catalyst was added and vacuum was gradually applied until the pressure reached 2,000 Pa. The process continued until the acidity index was less than 0.5 mg KOH / g, obtaining a polyether ester diol with a number average molecular weight of 3,500. Tests showed that the average functionality was 1.99, the viscosity at 90 °C and under a shear rate of 1 s⁻¹ was 34 Poise, and the material remained liquid at room temperature.

[086] Comparative Example 2: Preparation of a polyether ester diol with a number average molecular weight of 3.150 Petition 870250089421, dated 10 / 01 / 2025, pp. 37 / 46 31 / 37

[087] 17 parts by weight of diethylene glycol DEG (number average molecular weight of 106) and 23 parts by weight of terephthalic acid were added to a reactor. Nitrogen was introduced to replace the air inside the reactor. Stirring was started at 150 rpm. The system was heated in a programmed manner to 150 °C, maintaining this condition for 5 hours. Then, the temperature was raised to 225 °C, maintaining it until the water output rate reached 90% or more of the theoretical value and the solution became homogeneous. At this point, tetraisopropyl titanate catalyst was added and vacuum was gradually applied until the pressure reached 2,000 Pa. The process continued until the acidity index was less than 0.5 mg KOH / g, obtaining a polyether ester diol with a number average molecular weight of 3,150. Tests showed that the average functionality was 1.99, and the viscosity at 90 °C and under a shear rate of 1 s-1 was 2.000 Poise, and the material had a melting point of 70 °C.

[088] Comparative Example 3: Use of the polyether diol from Comparative Example 2 for the preparation of polyurethane elastomeric fibers

[089] 100 kg of the polyether ester diol obtained in Comparative Example 2 were added to a reactor previously heated to 45 °C. Stirring was started at a speed of 150 rpm. Then, 49 kg of dimethylacetamide (DMAc) were added to dissolve and reduce viscosity, followed by 17.1 kg of diphenylmethane diisocyanate. After 5 minutes of stirring, the temperature of the mixture was raised to 90 °C and maintained for 2 hours, forming the prepolymer. The prepolymer was cooled to Petition 870250089421, dated 10 / 01 / 2025, pages 38 / 46 The mixture was heated to 32 / 37 °C and dissolved in 100 kg of dimethylacetamide (DMAc). Subsequently, an amine solution with a mass concentration of 3.2%, containing 2.17 kg of ethylenediamine (EDA) and 0.27 kg of diethylamine (DEA), was added, and the stirring speed was increased to 300 rpm, promoting the chain extension reaction. After the chain extension reaction was complete, the necessary additives, such as antioxidants and dyeing aids, were added. The mixture was then subjected to a maturation process for 30 hours, obtaining a spinning solution with a solids content of 35%. This solution was used in a dry spinning process, resulting in PUU-6 elastomeric polyurethane fibers with a denier of 40D.

[090] In accordance with the test methods described above, the elastomeric polyurethane fibers (elastane fibers) obtained in Examples 2, 4, 6 as well as in Comparative Examples 1 and 3 were evaluated. The test results are summarized in the following table. Elastane fiber Tensile at 300% (cN) Breaking strength (cN) Elongation at break (%) 5LP2 00% (cN) 5UP20 0% (cN) Plastic deformation (%) 5UP200 % / 5LP200 % PUU-0 11.6 45.2 551 1.78 1.14 31.4 64.0% PUU-1 18.2 35.1 417 2.27 1.86 27.2 81.9% PUU-2 15.1 36.3 538 1.98 1.59 25.1 80.3% PUU-3 12.5 42.9 510 1.91 1.44 24.5 74.3% PUU-4 11.8 44.1 559 1.86 1.40 26.2 74.9% PUU-5 10.1 40.3 647 1.63 1.28 23.2 78.5% PUU-6 25.3 35.1 380 1.53 0.62 64.3 40.5%

[091] From the data in the table above, it can be observed that the polyurethane fibers obtained from the polyester-polyether polyol of the present invention exhibit Petition 870250089421, dated 10 / 01 / 2025, pp. 39 / 46 33 / 37 a significant reduction in the rate of plastic deformation, when compared to fibers produced from conventional polyether diols. Furthermore, the ratio between the return stress at 200% after the fifth stretching cycle and the elongation stress at 200% is closer to 1, indicating that the energy loss and hysteresis during the stretching and shrinking of the fibers are small, providing greater comfort when wearing the fabrics. Based on the value of 5UP200% (recovery stress / return to 200% after the fifth cycle), it is observed that the polyurethane fibers prepared with the polyether-ester diol of the present invention exhibit a higher return stress at 200%, that is, they have a higher recovery modulus, indicating greater elastic return strength and better ability to maintain the shape of the fabric.Comparing PUU-3 and PUU-4 fibers, it can be noted that the use of a mixture of polyether diols, instead of just polytetramethylene glycol, results in a reduction in the elongation at break of the elastomeric polyurethane fibers, while the elongation modulus and recovery modulus are increased. This plays a role in regulating the properties of polyurethane fibers, allowing the production of fibers with different requirements by adjusting the ratio of polyether diols.

[092] The spinning solutions from Examples 2, 4, 6, 8 and 10, as well as from Comparative Examples 1 and 3, were diluted from a solids content of 35% to 20% and then processed by immersion method to prepare polyurethane film gloves. The gloves were cut to obtain the corresponding film samples: Petition 870250089421, dated 10 / 01 / 2025, pages 40 / 46 34 / 37 PUU-F1, PUU-F2, PUU-F3, PUU-F4, and PUU-F5 for their respective Examples, and PUU-F0 and PUU-F6 for their respective Comparative Examples. The detailed steps for preparing the film samples are as follows:

[093] First, the hand mold was slowly immersed in a tank containing the diluted spinning solution. Then, the mold was removed from the solution tank, rotating it slowly to ensure a uniform thickness of the solution on the mold surface. Afterward, the mold was placed in a drying oven. After drying, the glove was removed from the mold, obtaining a polyurethane film glove with a thickness of approximately 150 µm. To test the mechanical properties of the glove, a portion of the glove palm was cut into strips 6 mm wide and 10 cm long, which were subjected to tests to evaluate the mechanical properties.

[094] The results for the mechanical properties are presented in the following table: Film sample Tension at 300% (N) Breaking strength (N) Elongation at break (%) 5LP20 0% (N) 5UP20 0% (N) Plastic deformation (%) 5UP200 % / 5LP200 % PUU-F0 12.24 15.64 1.14 0.73 23.68 64.0% PUU- F1 3.23 11.87 832 1.77 1.49 20.41 84.2% PUU- F2 2.78 12.51 1091 1.49 1.18 2.12.3% PUU- F1 2.30 14.75 1061 1.47 1.13 21.5 76.9% PUU- F4 2.19 15.16 1162 1.46 1.10 21.9 75.3% PUU- F5 1.85 13.61 128.90 .77.78 78.6% Petition 870250089421, of 01 / 10 / 2025, p. 41 / 46 35 / 37 PUU- F6 4.41 11.71 802 0.43 0.18 65.1 41.9%

[095] From the data presented in the table, it can be observed that the polyurethane film gloves prepared with the polyether-ester diol of the present invention exhibit a low rate of plastic deformation, which confers greater dimensional stability to the product. Furthermore, analyzing the 5UP200% values, it is verified that the polyurethane films prepared with the polyether-ester diol of the present invention have greater recovery strength at 200%, resulting in better glove fit to the hands. In addition, maintaining this adhesion strength, it is possible to manufacture thinner gloves, thus reducing the raw material cost of the polyurethane film gloves. Comparing the PUU-F3 and PUU-F4 samples, it can be noted that the use of a polyether diol mixture, instead of just polytetramethylene glycol, results in a reduction in the elongation at break of the samples, while the elongation modulus and the recovery modulus show an increase.This highlights that the mixture plays an important role in adjusting the properties of the polyurethane film.

[096] Example 14: Melt spinning of elastane yarn prepared from the polyether ester diol of Example 1

[097] The polyether ester diol of Example 1, 1,4-butanediol and diphenylmethane diisocyanate were dosed in a molar ratio of 1.2:1:2.2, respectively, and introduced into a twin-screw extruder. The continuous polymerization reaction was carried out at 195°C, followed by extrusion, underwater granulation and drying until the moisture content of the polyurethane granules was less than 100 Petition 870250089421, dated 10 / 01 / 2025, pages 42 / 46 36 / 37 ppm. Subsequently, antioxidants, light stabilizers, and other necessary additives were added, and the material underwent melt spinning, yielding a TPU-1 elastane yarn with a denier of 20D.

[098] Comparative Example 4: Melt spinning of elastane yarn prepared from polytetramethylene glycol (PTMG) with an average molecular weight of 2000

[099] Polytetramethylene glycol PTMG2000 (average molecular weight 2000), 1,4-butanediol and diphenylmethane diisocyanate were dosed in a molar ratio of 1.2:1:2.2 and introduced into a twin-screw extruder. The continuous polymerization reaction was carried out at 190 °C, followed by extrusion, underwater granulation and drying until the moisture content of the polyurethane granules was less than 100 ppm. Then, antioxidants, light stabilizers and other necessary additives were added, and the material underwent melt spinning, obtaining a TPU-0 elastane yarn with a denier of 20D. Elastic yarn Tension at 300% (cN) Tensile strength (cN) Elongation at break (%) 5LP200% (cN) 5UP200% (cN) Plastic deformation (%) 5UP200% / 5LP200% TPU-0 12.3 45.0 540 1.78 1.14 32.8 64.0% TPU-1 17.3 40.1 476 2.29 1.83 28.2 79.9%

[0100] Comparison of the mechanical properties of Examples and Comparative Examples above show that melt-processed elastane yarn using polyether ester diol as raw material exhibits significantly higher tensile strength and recovery modulus than melt-processed elastane yarn using Petition 870250089421, dated 10 / 01 / 2025, pages 43 / 46 37 / 37 polytetramethylene glycol as raw material, in addition to exhibiting a lower rate of plastic deformation. These results demonstrate mechanical characteristics and advantages similar to those observed in elastane yarns processed by the dry spinning method from solution. Petition 870250089421, dated 10 / 01 / 2025, pp. 44 / 46

Claims

1 / 2 CLAIMS 1. A polyester-polyether polyol characterized by comprising repeating units of formula (1) and terminal hydroxyl groups derived from alcohols: OO Γ II II zx Ί — C-Ri-C-O4 R2 -Oή-X m Formula (1) wherein Ri is chosen from at least one aromatic or heteroaromatic ring group, the mass content of Ri in formula (1) being between 4.5% and 44%; R2 is chosen from at least one saturated alkyl group containing from 2 to 5 carbon atoms; x is an integer between 2 and 20; the repeating units of formula (1) represent more than 75% by mass of the polyester-polyether polyol; the average functionality of the terminal hydroxyl groups is from 1.95 to 2.00; The number-average molecular weight of polyester-polyether polyol is in the range of 800 to 5000. 2.0 polyester-polyether polyol according to claim 1, characterized in that R2 is at least one saturated alkyl group containing from 2 to 5 carbon atoms.

3. A process for preparing polyester-polyether polyol, characterized by ensuring the reaction of an aromatic dicarboxylic acid, or its ester or anhydride, with a polyether diol, to obtain the polyester-polyether polyol according to claim 1.

4. The preparation process according to claim 3, characterized in that the polyether diol has a numerical average molar mass between 100 and 1000, preferably a degree of polymerization between 2 and 20, more preferably between 3 and 10.

5. The preparation process according to claim 4, characterized in that the polyether diol is a copolymer obtained from the reaction of at least two of tetrahydrofuran, ethylene oxide, propylene oxide, 2-methyltetrahydrofuran and 3-methyltetrahydrofuran.

6. The preparation process according to claim 4, characterized in that the polyether diol is a mixture of at least two of polytetrahydrofuran, polypropylene glycol and polyethylene glycol.

7. The process and use of polyester-polyether polyol according to any one of claims 1 or 2, or of polyester-polyether polyol obtained by the method of any one of claims 3 to 6, characterized by employing said polyester-polyether polyol as a raw material for the preparation of polyurethane elastomeric fibers, nonwovens, films or elastomers, the preparation being carried out by solution processing or by melt processing.

8. Polyurethane elastomeric fibers, nonwovens, films or elastomers characterized by being obtained by the method according to claim 7. Petition 870250089421, dated 10 / 01 / 2025, page 46 / 46