POLYESTER-POLYETHER POLYOL, PREPARATION PROCESS AND ITS USE

Abstract

The present application relates to a polyether ester polyol, comprising repeated formula (1) structures and end-capped alcohol hydroxyl groups: formula (1), wherein R1 is selected from at least one of an aromatic ring or an heteroaromatic ring, and the mass content of R1 in the repeated formula (1) structures is 4.5%-44%; R2 is selected from at least one of saturated alkane groups having 2-3 carbon atoms; x is 2-20; the mass percentage of the repeated formula (1) structures in the polyether ester polyol is greater than 75%; the average functionality of the end-capped alcohol hydroxyl groups is 1.95-2.00; and the number-average molecular weight of the polyether ester polyol is 800-5000. The present application also relates to a preparation method for a polyether ester polyol, and a method for preparing a polyurethane elastic fiber, non-woven fabric, membrane or elastomer by using the polyether ester polyol, so that a polyurethane product prepared from a raw material having lower costs can still achieve similar mechanical properties, and meet the requirements of subsequent use.

Description

1 / 36 POLYESTER-POLYETHER POLYOL, PREPARATION PROCESS AND ITS USE TECHNICAL FIELD

[001] The present invention relates to the field of polyurethane elastic fibers (hereinafter referred to as elastanes), more specifically to a polyester-polyether polyol, its method of preparation and its use in the production of polyurethane elastic fiber, nonwovens, films or 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 high crystallization capacity, 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 870250089321, dated 10 / 01 / 2025, page 7 / 42 2 / 36 disordered, which guarantees excellent elastic recovery capacity.

[003] Elastane, that is, the elastic polyurethane fiber, currently in industrial production, to ensure that it exhibits sufficient elongation and a low rate of plastic deformation, generally uses polytetramethylene glycol (PTMEG) as a raw material for the flexible segment. However, polytetramethylene glycol has a high cost and is used in large quantities in the production of elastane, directly increasing the production cost. Some polyester-type diols, such as adipic acid-based polyesters, offer a certain cost advantage as raw materials; however, these products have limitations such as low alkali resistance, low hydrolysis resistance, and a tendency to mold. Polyether diols, such as polyethylene glycol (PEG) and polypropylene glycol (PPG), have a lower cost, but elastane produced from PEG exhibits high permanent deformation and a low recovery modulus, while that produced from PPG has a reduced modulus.Furthermore, elastanes synthesized from PEG or PPG exhibit inferior tear strength, making them unsuitable for end-use applications.

[004] In industrial production, it is desirable for elastane to perform well while reducing production costs. To this end, the present invention starts from the materials used in the preparation of polyurethane elastic fiber, seeking to provide a polyester-polyether polyol that, compared to PTMEG, presents Petition 870250089321, dated 10 / 01 / 2025, page 8 / 42 3 / 36 lower cost and, when used in the production of polyurethane elastic fiber, results in fibers with mechanical performance similar to that obtained from PTMEG, fully meeting the requirements for the use of elastane. SUMMARY OF THE INVENTION

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

[006] The polyester-polyether polyol of the present invention comprises a repeating structure of Formula (1) and terminal hydroxyl groups: wherein Ri is at least one aromatic ring or heteroaromatic ring, and the mass content of Ri in Formula (1) varies from 4.5% to 44%. R2 is at least one saturated alkyl group containing 2 to 3 carbon atoms; x varies from 2 to 20.

[007] The repetitive structure of Formula (1) represents more than 75% of the mass 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.

[010] In one embodiment, the melting point of the polyester-polyether polyol is below 80 °C, being Petition 870250089321, dated 10 / 01 / 2025, p. 9 / 42 4 / 36 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] 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 from two or more of the following: terephthalic acid, isophthalic acid, phthalic acid, biphenyl-4,4'-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,3-dicarboxylic acid, 2,5-furanedicarboxylic acid, p-phenylenediacetic acid, m-phenylenediacetic acid, o-phenylenediacetic acid. Considering cost, the preferred acids in this invention are terephthalic acid, isophthalic acid, phthalic acid, or 2,5-furanodicarboxylic acid.Polyester-polyether polyols produced from these compounds as aromatic dicarboxylic acids offer a greater cost advantage. The respective esters can be obtained by reacting the aromatic dicarboxylic acid with a monoalcohol with a boiling point below 150 °C.

[012] In another embodiment, the polyether diol has a number average molecular weight of 100 to 1,000, preferably having a degree of polymerization of 2 to 20, and more preferably between 3 and 10. Petition 870250089321, dated 10 / 01 / 2025, page 10 / 42 5 / 36

[013] The present embodiment also provides a method for producing polyurethane elastic fiber, nonwovens, films or elastomers, using as raw material the polyester-polyether polyol described in the invention, and the products obtained from this method.

[014] In specific implementations, polyurethane elastic fibers, nonwovens, films or elastomers are prepared by solution processing or by melt processing. Beneficial Effects:

[015] The polyester-polyether polyol of the present invention uses aromatic dicarboxylic acids and polyether diols with 2-3 carbon atoms (such as PEG and / or PPG) as raw materials, both of which are low cost, providing a significant economic advantage compared to the use of PTMEG. Furthermore, the alternating arrangement of the 2-3 carbon atom polyether segments with the aromatic rings of the dicarboxylic acid through ester linkages significantly increases the tensile strength and recovery modulus of polyurethane fibers obtained from PEG or PPG, while significantly reducing permanent deformation. Thus, these fibers exhibit mechanical properties comparable to conventional polyurethane fibers produced from PTMEG, making the lower-cost materials suitable for textile applications. DETAILED DESCRIPTION OF THE INVENTION

[016] Currently, the most common method for producing polyurethane elastic fiber uses polyether diol as raw material, especially Petition 870250089321, dated 10 / 01 / 2025, p. 11 / 42 6 / 36 polytetramethylene glycol. This is initially reacted with a diisocyanate to form a prepolymer, which is then subjected to chain extension in the presence of chain extenders and a terminator. However, polytetramethylene glycol is expensive and is used in large quantities in the production of polyurethane elastic fiber, directly increasing the cost of elastane production. Some diol polyesters, such as adipic acid-based polyesters, offer a certain cost advantage as raw materials; however, the resulting products have disadvantages such as low alkali resistance, low hydrolysis resistance, and susceptibility to mold. Low-cost diol polyethers, such as polyethylene glycol (PEG) and polypropylene glycol (PPG), when used as raw materials for the flexible segments of elastane, have limitations in tensile strength and modulus of elasticity.Furthermore, fabrics containing elastane require that the fibers possess a certain recovery modulus, allowing the fabric, after deformation, to overcome the resistance of the other fibers present and return to its original shape, ensuring shape retention. In conventional technologies, increasing the recovery modulus generally results in an increase in the rate of plastic deformation. However, the inventors unexpectedly discovered a polyester-polyether polyol that, compared to polytetramethylene glycol, has a lower cost and, when used as a raw material in the production of polyurethane elastic fiber, generates fibers with excellent mechanical performance, not only meeting the requirements of use, but also... Petition 870250089321, dated 10 / 01 / 2025, page 12 / 42 7 / 36 also exhibiting a higher recovery modulus and a lower rate of plastic deformation.

[017] Unless otherwise indicated, the term polyether diol mentioned below refers to polyether diols with monomers containing 2 to 3 carbon atoms.

[018] Specifically, the present invention provides a polyester-polyether polyol comprising a repeating structure of Formula (1) and hydroxyl termination: ΓII — c- R1-C-0 R2 — om Formula (1), where Ri is selected from at least one aromatic ring or heteroaromatic ring, with the mass content of Ri in Formula (1) ranging from 4.5% to 44%; R2 is selected from at least one saturated alkyl group containing 2 to 3 carbon atoms; x can range from 2 to 20. The repeating structure of Formula (1) represents more than 75% of the mass of the polyester-polyether polyol. When the content of aromatic groups Ri 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 aromatic groups Ri is too low, the effect of increasing the recovery modulus of polyurethane fibers will not be achieved.

[019] The aromatic ring may be selected from at least one of the following: benzene ring, naphthalene ring, anthracene ring, or phenanthrene ring. The heteroaromatic ring may Petition 870250089321, dated 10 / 01 / 2025, page 13 / 42 8 / 36 can be selected from at least one of pyridine, furan, thiazole, or pyrimidine. In an optional embodiment, in addition to the aromatic or heteroaromatic ring, Ri may also include 1 to 4 methylene groups.

[020] In a preferred embodiment, the polyester-polyether polyol of the present invention has a linear overall structure in which the 2-3 carbon atom polyether segments are arranged alternately with aromatic rings. During development, the inventors discovered that the use of rigid aromatic rings to space the 2-3 carbon atom polyether segments significantly increases the mechanical properties of the elastane fibers obtained from this polyol, allowing PEG and PPG to be used in the production of elastic polyurethane fibers and improving the fibers' resistance to plastic deformation. Furthermore, the introduction of aromatic or heteroaromatic rings gives the polyurethane fibers a higher modulus of elasticity. The use of 2-3 carbon atom polyether segments, compared to the polyether structure of polytetramethylene glycol, offers a significant cost advantage in production.In a 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 consists exclusively of the repeating structure of Formula (1) and the hydroxyl termination.

[021] According to the present invention, the average functionality of the terminal hydroxyl groups of Petition 870250089321, dated 10 / 01 / 2025, p. 14 / 42 The 9 / 36 polyester-polyether polyol functionality can range from 1.95 to 2.00, preferably from 1.96 to 2.00, and more preferably from 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 via small amine or alcohol molecules. When the average functionality is greater than 2.00, the use of polyester-polyether polyol as a raw material for polyurethane production can result in the formation of cross-linked structures, preventing the formation of linear chain polyurethane. Such polyurethane tends to gel during continuous production, hindering the continuity of the process. On the other hand, if the average functionality is too low, the resulting polyurethane 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.

[022] Here, “average functionality” refers to the average number of moles of reactive hydroxyl termination per mole of polyester-polyether polyol. In the present invention, considering the possible formation of double bonds by dehydration of the hydroxyl groups of the polyether diol, as well as the presence of unreacted carboxyl groups, the average functionality of the hydroxyls can be calculated by the following formula: Functionality = 2 χ moles of hydroxyl / Petition 870250089321, dated 10 / 01 / 2025, p. 15 / 42 10 / 36 (moles of hydroxyl + moles of carboxyl + moles of double bonds).

[023] The number-average molecular weight of the polyester-polyether polyol of the present invention may 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 elastic fibers.

[024] 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 shear rate of 1 s-1, preferably less than 200 Poise.

[025] 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 Petition 870250089321, dated 10 / 01 / 2025, page 16 / 42 11 / 36 transport, ensuring the viability of continuous operations on an industrial scale. Otherwise, it would be necessary to heat it to promote its melting, which would increase energy consumption.

[026] The present invention also provides a method for preparing the polyester-polyether polyol described above, which comprises the condensation or transesterification reaction of an aromatic dicarboxylic acid, its ester or its anhydride with a polyether diol containing 2 to 3 carbon atoms in the monomeric unit.

[027] 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, biphenyl-4,4'-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,3-dicarboxylic acid, furan-2,5-dicarboxylic acid, p-phenylenediacetic acid, m-phenylenediacetic acid, o-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; Preferably, the monoalcohol is methanol or ethanol.Furthermore, compared to aromatic dicarboxylic acids, the respective esters allow the transesterification reaction with polyether diol to occur under milder conditions, which is advantageous for the design. Petition 870250089321, dated 10 / 01 / 2025, page 17 / 42 12 / 36 of the production process. The aromatic dicarboxylic acid used can come from recycled plastics, which allows for the reuse of waste, reducing the production costs of polyurethane elastic fibers and meeting the requirements of a green economy.

[028] According to the method of the present invention, the polyether diol with 2 to 3 carbon atoms in the monomeric unit 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, the structure obtained, in which the polyether segments are arranged alternately with the aromatic rings, can 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 polyurethane elastic 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. Polyether diol can be obtained by ring-opening polymerization of epoxy monomers or by polycondensation of low molecular weight diols; it can be a homopolymer synthesized from a single monomer. Petition 870250089321, dated 10 / 01 / 2025, page 18 / 42 13 / 36 or a copolymer synthesized from two or more monomers. For example, suitable polyether diols for the present invention may be polyethylene glycol (PEG) or polypropylene glycol (PPG). In practical production, polyether diols with monomers containing 2-3 carbon atoms may also be used, such as the copolymer diol obtained by the reaction of ethylene oxide, propylene oxide and tetramethylene glycol.

[029] 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.

[030] The polyester-polyether polyol of the present invention can be prepared by vacuum esterification or by transesterification, generally carried out in two steps. Petition 870250089321, dated 10 / 01 / 2025, page 19 / 42 14 / 36

[031] 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 rate of water leaving the system reaches 90% or more, with the rate of water leaving defined as: rate of water leaving = amount of water released / (moles of dicarboxylic acid χ 36).

[032] After the first esterification stage is complete, 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 system's acidity index 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 Petition 870250089321, dated 10 / 01 / 2025, page 20 / 42 15 / 36 considered complete, heating is stopped, and the material is discharged after the system temperature decreases to a suitable value, usually below 90 °C.

[033] 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, and the hydroxyl groups of the polyether diol must be 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.

[034] The present invention also provides a method for using polyurethane products, such as polyurethane elastic 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).

[035] The method for preparing polyurethane comprises the following two steps: (1) Reacting the polyester-polyether polyol with a diisocyanate to form a prepolymer; and (2) Polymerizing said prepolymer with a chain extender and a termination agent. Petition 870250089321, dated 10 / 01 / 2025, p. 21 / 42 16 / 36 chain. The one-step polyurethane preparation method (single-container method) comprises: (1) (1) Add the polyester-polyether polyol, the diisocyanate, and a low molecular weight diol-type chain extender to a reaction vessel; (2) Mix the materials in the reaction vessel and heat to promote the reaction, or heat 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, di-tert-butylamine, diisobutylamine, diisopropylamine, cyclohexylamine, or ethanolamine. Petition 870250089321, dated 10 / 01 / 2025, page 22 / 42 17 / 36

[036] 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 elastic fibers, nonwovens, films and elastomers — including solution or melt processing methods — can be applied in the present invention. For example, polyurethane elastic 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, immersion, melt extrusion, film blowing, or casting, as described in the scrape coating method in patent document JP2005205787A, the immersion method in patent document WO2015064776A1, the extrusion method in patent document GB1137520A, the film blowing method in patent document DE2239478A1, and the casting method in patent document JP2004203933A. Elastomers can be processed by methods such as extrusion, injection molding, or casting, as described in the extrusion methods section of the patent document. Petition 870250089321, dated 10 / 01 / 2025, page 23 / 42 18 / 36 JP1996027376A, the injection method of patent document US3917792A, and 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 elastic fibers, nonwovens, films, and elastomers mentioned above are merely 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 known technique or process. Examples of Achievement

[037] 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:

[038] 1. Average Functionality:

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

[040] 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 27091995; 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 converted into moles of the respective terminal groups present in the polyether ester diol. Petition 870250089321, dated 10 / 01 / 2025, page 24 / 42 19 / 36

[041] 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.

[042] 3. Plastic Deformation Test:

[043] 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.

[044] 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.

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

[046] In this formula, 5LP200% represents the tensile stress of 200% in the fifth cycle, i.e., F1. 5UP200% represents the recovery stress of 200% in the fifth cycle of return from 300% to 200% elongation, i.e., F2, which can be used to characterize the recovery modulus. The rate of plastic deformation represents the Petition 870250089321, dated 10 / 01 / 2025, p. 25 / 42 20 / 36 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.

[047] 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.

[048] Example 1: Preparation of a polyether ester diol with a number average molecular weight of 2.120

[049] 17 parts by weight of PPG600 polypropylene glycol (number average molecular weight of 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 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 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 18 Poise, and the material remained liquid at room temperature. Petition 870250089321, dated 10 / 01 / 2025, p. 26 / 42 21 / 36

[050] Example 2: Use of the polyether-ester diol from Example 1 in the preparation of polyurethane elastic fiber

[051] 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 rate 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.

[052] The prepolymer was cooled to 50 °C and dissolved in 154.4 kg of dimethylacetamide (DMAc). Subsequently, a 3% amine solution containing 2.25 kg of ethylenediamine and 0.28 kg of diethylamine 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 elastic polyurethane fiber with a denier of 40D.

[053] Example 3: Preparation of a polyether ester diol with a number average molecular weight of 1,500

[054] 17 parts by weight of PPG600 polypropylene 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 Petition 870250089321, dated 10 / 01 / 2025, page 27 / 42 22 / 36 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 1,500. Tests showed that the average functionality was 1.98, the viscosity at 90 °C and under a shear rate of 1 s⁻¹ was 12 Poise, and the material remained liquid at room temperature.

[055] Example 4: Use of the polyether-ester diol from Example 3 for the preparation of polyurethane elastic fiber

[056] 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 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.

[057] 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 and 0.28 kg of diethylamine, was added, and the stirring speed was increased to 300 rpm, promoting the reaction of Petition 870250089321, dated 10 / 01 / 2025, page 28 / 42 23 / 36 chain extension. 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 elastic polyurethane fiber with a denier of 40D.

[058] Example 5: Preparation of a polyether ester diol with a number average molecular weight of 4,700

[059] 17 parts by weight of PPG600 polypropylene 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 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 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. Petition 870250089321, dated 10 / 01 / 2025, p. 29 / 42 24 / 36

[060] Example 6: Use of the polyether ester diol from Example 5 for the preparation of polyurethane elastic fiber

[061] 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 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.

[062] 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 and 0.26 kg of diethylamine, 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 elastic polyurethane fiber with a denier of 40D.

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

[064] 100 kg of polytramethylene glycol PTMG2000 (average molecular weight) were added Petition 870250089321, dated 10 / 01 / 2025, pages 30 / 42 25 / 36 (numerical value of 2,000) 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.

[065] 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 elastic polyurethane fiber with a denier of 40D.

[066] Example 7: Preparation of a polyether ester diol with a number average molecular weight of 3.140

[067] 17 parts by weight of PEG200 polyethylene glycol (number average molecular weight of 200) and 3.7 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 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 Petition 870250089321, dated 10 / 01 / 2025, pages 31 / 42 26 / 36 that 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 3,140. Tests showed that the average functionality was 1.97, the viscosity at 90 °C and under a shear rate of 1 s⁻¹ was 10⁵ Poise, and the material remained liquid at room temperature.

[068] Example 8: Preparation of a polyether ester diol with a number average molecular weight of 3,250

[069] 17 parts by weight of PPG1000 polypropylene 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 then heated to 150 °C and maintained at that temperature for 5 hours. The temperature was then 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 to 2,000 Pa. The process continued until the acid value was less than 0.5 mg KOH / g, obtaining a 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 rate of Petition 870250089321, dated 10 / 01 / 2025, pages 32 / 42 The shear strength of 27 / 36 s⁻¹ was 32 Poise, and the melting point was 32.1 °C.

[070] Example 9: Preparation of a polyether ester diol with a number average molecular weight of 3,500

[071] Seventeen parts by weight of polypropylene glycol 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. 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 to 2,000 Pa. The process continued until the acid value 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 si was 28 Poise, and the material remained liquid at room temperature.

[072] Comparative Example 2: Preparation of a polyether ester diol with a number average molecular weight of 3,150

[073] 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 increased. Petition 870250089321, dated 10 / 01 / 2025, pages 33 / 42 The temperature was increased from 28 / 36 to 225 °C, maintaining the temperature 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, 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.

[074] Comparative Example 3: Use of the polyether diol from Comparative Example 2 for the preparation of polyurethane elastic fiber

[075] 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 50 °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 and 0.27 kg of diethylamine, 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 were added, such as Petition 870250089321, dated 10 / 01 / 2025, pages 34 / 42 29 / 36 antioxidants and dyeing aids. 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 elastic polyurethane fiber with a denier of 40D.

[076] Comparative Example 4: Use of polyethylene glycol with a number average molecular weight of 1,500 for the preparation of polyurethane elastic fiber

[077] 100 kg of polyethylene glycol with a molecular weight of 1500 were added to a reactor previously heated to 45 °C. Stirring was started at a speed of 150 rpm. 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.

[078] 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 2.32 kg of ethylenediamine and 0.28 kg of diethylamine, 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 elastic polyurethane fiber with a denier of 40D. Petition 870250089321, dated 10 / 01 / 2025, pages 35 / 42 30 / 36

[079] Comparative Example 5: Use of polypropylene glycol with a number average molecular weight of 2,000 for the preparation of polyurethane elastic fiber

[080] 100 kg of 2000 molecular weight polypropylene glycol were added to a reactor previously heated to 45 °C. Stirring was started at a speed of 150 rpm. Then, 21.98 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.

[081] The prepolymer was cooled to 50 °C and dissolved in 155.24 kg of dimethylacetamide (DMAc). Subsequently, an amine solution with a mass concentration of 3.2%, containing 2.24 kg of ethylenediamine and 0.28 kg of diethylamine, 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 elastic polyurethane fiber with a denier of 40D.

[082] According to the test methods described above, the polyurethane elastic fibers (elastane fibers) obtained in Examples 2, 4 and 6 as well as in Comparative Examples 1, 3, and 5 were evaluated. The test results are summarized in the following table. Petition 870250089321, dated 10 / 01 / 2025, pages 36 / 42 31 / 36 Elastane fiber Tensile at 300% (cN) Breaking strength (cN) Elongation at break (%) 5LP20 0% (cN) 5UP20 0% (cN) Plastic deformation (%) 5UP200 % / 5LP200 % PUU-0 12.1 45.3 550 1.88 1.21 31.4 64.4% PUU-1 15.0 35.9 542 1.95 1.56 25.2 80.0% PUU-2 17.9 34.8 423 2.22 1.83 27.3 82.4% PUU-3 10.5 40.3 652 1.60 1.26 23.1 78.8% PUU-4 25.4 34.8 381 1.49 0.60 64.4 40.3% PUU-5 6.2 12.1 417 1.02 0.75 63.5 73.5% PUU-6 8.9 25.2 703 0.91 0.72 30.1 79.1%

[083] From the data in the table above, it can be observed that the polyurethane elastic fibers obtained from the polyester-polyether polyol of the present invention exhibit a significant increase in tensile strength and rupture resistance when compared to polyurethane elastic fibers obtained from polyethylene glycol and polypropylene glycol as raw materials. These values ​​approach or even exceed those of polyurethane elastic fibers conventionally prepared from polytetramethylene glycol, fully meeting the performance requirements of elastane used in clothing. Furthermore, the plastic deformation rate of the polyurethane elastic fibers prepared from the polyester-polyether polyol of the present invention shows a significant reduction.Based on the 5UP200% value, it is observed that the polyurethane fibers prepared with the polyether-ester diol of the present invention exhibit a higher 5UP200% recovery strength, i.e., they have a higher recovery modulus, indicating greater elastic recovery strength and better ability to maintain the shape of the fabric. Therefore, the polyether-ester polyol provided by the present invention... Petition 870250089321, dated 10 / 01 / 2025, pp. 37 / 42 32 / 36 effectively improves the mechanical properties of fibers when polyethers with a carbon atom number between 2 and 3 are used as flexible segments in polyurethane fibers. Compared to conventional polyurethane fibers obtained from polytetramethylene glycol, it exhibits similar mechanical performance, potentially reducing the production cost of elastane and significantly improving its performance in use.

[084] The spinning solutions from Examples 2, 4, and 6, as well as from Comparative Examples 1, 3, 4, and 5, 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: PUU-F1, PUU-F2, and PUU-F3 for their respective Examples, and PUU-F0, PUU-F4, PUU-F5, and PUU-F6 for their respective Comparative Examples. The detailed steps for preparing the film samples are as follows:

[085] 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. Afterwards, 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 Petition 870250089321, dated 10 / 01 / 2025, pages 38 / 42 33 / 36 submitted to tests for evaluation of mechanical properties.

[086] 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 12.26 15.15 1.13 0.73 23.75 64.6% PUU- F1 2.81 12.53 1103 1.44 1.15 18.92 79.9% PUU- F2 3.36 11.82 842 1.72 1.42 1.42% PUU- F1 838 1.83 13.54 1306 0.92 0.72 17.33 78.3% PUU- F4 4.42 11.71 799 0.42 0.18 65.3 42.9% PUU- F5 73.3% PUU- F6 1.68 8.42 1379 0.41 0.32 32.5 78%

[087] From the data presented in the table, it can be observed that the glove films prepared with the polyester-polyether polyol of the present invention, when tested on cut palm samples, show, in comparison with the thin film obtained from polyethylene glycol and polypropylene glycol, a significant increase in tensile strength and tear resistance. These values ​​approach or even exceed those of films prepared from polytetramethylene glycol, fully meeting the mechanical performance requirements of elastic film gloves. This result is consistent with the phenomenon observed in elastane fibers. At the same time, the polyurethane film gloves prepared with the polyether-ester diol of the present invention exhibit a Petition 870250089321, dated 10 / 01 / 2025, pages 39 / 42 34 / 36 low plastic deformation rate, 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 recovery strength, it is possible to manufacture thinner gloves, thus reducing the raw material cost of polyurethane film gloves. In summary, the polyester-polyether polyol provided by the present invention effectively improves the mechanical properties of the films when polyethers with 2-3 carbon atoms per monomer are used as flexible segments in polyurethane fibers.Based on this, thin glove films exhibit a lower rate of plastic deformation and a higher modulus of recovery, which contributes to maintaining the product's shape, improves the fit of the gloves to the hands, and at the same time allows for a reduction in the cost of raw material production.

[088] Example 10: Melt spinning of elastane yarn prepared from the polyether ester diol of Example 3

[089] The polyether ester diol of Example 3, 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 ppm. Antioxidants were then added, Petition 870250089321, dated 10 / 01 / 2025, pp. 40 / 42 35 / 36 light stabilizers and other necessary additives were added, and the material underwent melt spinning, resulting in a TPU-1 elastane yarn with a denier of 20D.

[090] Comparative Example 6: Melt spinning of elastane yarn prepared from polytramethylene glycol (PTMG) with an average molecular weight of 2000. Polytramethylene 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.

[091] Comparative Example 7: Melt spinning of elastane yarn prepared from polyethylene glycol (PEG) with an average molecular weight of 1500

[092] Polyethylene glycol with an average molecular weight of 1500, 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. Antioxidants, light stabilizers, and other additives were then added. Petition 870250089321, dated 10 / 01 / 2025, pp. 41 / 42 36 / 36 was required, and the material underwent melt spinning, resulting in a TPU-2 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 45 540 1.775 1.14 32.8 64.5% TPU-1 17.5 40 485 2.21 1.77 28.2 82.4% TPU-2 5.5 11 416 0.986 0.712 38.2 72.3% [093 Comparison of the mechanical properties of Examples and Comparative Examples above show that melt-processed elastane yarn using polyether ester diol as feedstock exhibits significantly higher tensile strength and recovery modulus than melt-processed elastane yarn using polytetramethylene glycol as feedstock. These results demonstrate mechanical characteristics and advantages similar to those observed in elastane yarns processed by the dry spinning method from solution. Petition 870250089321, dated 10 / 01 / 2025, page 42 / 42

Claims

1 / 3 CLAIMS 1. A polyester-polyether polyol characterized by comprising repeating units of formula (1) and terminal hydroxyl groups derived from alcohols: OO r II II / λ Ί --C - Ri — C — OV R2 — O -A-- 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 2 to 3 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 1.95 to 2.00; The number-average molecular weight of the polyester-polyether polyol is in the range of 800 to 5000.

2. The polyester-polyether polyol according to claim 1, characterized by having a melting point below 80 °C, being preferably liquid at room temperature. 3.The polyester-polyether polyol according to claim 1, characterized by having a viscosity of less than 500 Poise at 90 °C and under a shear rate of 1 s-1.

4. A process for preparing a 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. 5.The production process according to claim 4, characterized in that the aromatic dicarboxylic acid is selected from terephthalic acid, isophthalic acid, phthalic acid, 4,4'-biphenyl dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, 2,5-furan dicarboxylic acid, p-phenylene diacetic acid, m-phenylene diacetic acid and p-phenylene diacetic acid, alone or in combination of two or more, preferably the respective ester obtained by reacting the aromatic dicarboxylic acid with a monoalcohol with a boiling point below 150 °C.

6. The process for preparing polyester-polyether polyol according to claim 4, characterized in that the polyether diol has a number-average molar mass between 100 and 1000, preferably having a degree of polymerization between 2 and 20, and more preferably between 3 and 10. 7.The process and use of polyester-polyether polyol according to any one of claims 1 to 3, or polyester-polyether polyol obtained by the method of any one of claims 4 to 6, characterized in that said polyester-polyether polyol is 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. Petition 870250070713, dated 11 / 08 / 2025, p. 14 / 17 3 / 3 8. The process for preparing polyurethane elastomeric fibers, nonwovens, films or elastomers according to claim 7, characterized in that it includes the steps of: (1) reacting the polyester-polyether polyol with a diisocyanate to form a prepolymer; and (2) polymerizing said prepolymer with a chain extender, or with a mixture of chain extender and terminating agent. 9.The process for preparing polyurethane elastomeric fibers, nonwovens, films or elastomers according to claim 7, characterized by including the steps of: (1) separately adding the polyester polyether polyol, diisocyanate and chain elongation agent to a reaction vessel; (2) Mix the materials in the container and heat to promote the reaction, or heat during the mixing process to carry out the reaction.

10. Polyurethane elastomeric fibers, nonwovens, films or elastomers characterized by being obtained by the method of any of claims 7 to 9. Petition 870250070713, dated 11 / 08 / 2025, p. 15 / 17