Method for producing polyether ester polyols and their products

Abstract

[Problem] To provide a method for producing polyether ester polyols and their products. [Solution] The method involves placing polyetherdiol and polyester as raw materials into a reaction vessel, raising the temperature to the reaction temperature to carry out a transesterification reaction, and removing the low molecular weight polyol produced by the reaction by vacuum distillation to obtain a polyether ester polyol. Here, the polyester contains an aromatic dibasic acid-polyol ester structure, the degree of polymerization of the polyetherdiol is 2 to 20, the molecular weight is 100 to 1000, the molar ratio of the polyetherdiol to the aromatic group structure in the polyester is greater than 1.05:1, and the reaction temperature is set to a range higher than the boiling point of the low molecular weight polyol and lower than the boiling point of the polyetherdiol. The method of the present invention allows for the direct processing of recovered polyester into a polyether ester polyol suitable for the production of polyurethane elastic fibers, simplifying the production process of polyols for spandex and simultaneously achieving resource reuse and expansion of raw material sources. Furthermore, the present invention provides an easily dyeable spandex obtained by blending the above polyether ester polyol with a diol-based raw material and a method for producing the same. The resulting spandex contains specific aromatic group-polyether block structures within its molecular soft segments, improving dyeing rate and fixation to disperse dyes and acid dyes without compromising mechanical performance compared to conventional products. Furthermore, by adjusting the mass ratio of these block structures within the soft segments, it is possible to achieve both sufficient dyeability and excellent alkali resistance.

Description

[Technical Field]

[0001] [Claiming priority] This invention claims priority based on Chinese invention patent application 202310424908.4 (title: "Method for producing polyether ester polyols and their products"), filed with the China National Intellectual Property Administration on April 18, 2023.

[0002] Furthermore, we claim priority based on Chinese invention patent application 202410455754.X (title: "Easy-to-dye spandex and method for manufacturing the same"), which was filed with the China National Intellectual Property Administration on April 16, 2024.

[0003] The present invention relates to the field of polymers and methods for producing the same products, and more specifically to polyether ester polyols and methods for producing the same products. [Background technology]

[0004] Polyester is a versatile engineering material known for its excellent performance. Polyesters containing benzene rings in their structure, such as polyethylene terephthalate (PET), polypropylene terephthalate (PPT), and polybutylene terephthalate (PBT), are particularly common. These are used in fibers, bottles, films, and other plastic products, making them essential plastic items in daily life.

[0005] On the other hand, as the use of polyester plastic products becomes more widespread, environmental problems caused by their irredegradability are attracting attention. Plastic recycling is an effective means of solving environmental problems, and the currently dominant recovery method is to remelt and pelletize recovered bottle flakes to create recycled material, which is then reprocessed to manufacture plastic products. However, this method has high quality requirements for recovered flakes, requiring low levels of impurities, small color differences, and small molecular weight differences, making it difficult to reuse much of the plastic waste that does not meet these standards. In addition to repelling, there is also a method in which impurities are removed from recovered polyester plastic, and then it is depolymerized by chemical methods to break it down into terephthalic acid (PTA) or dimethyl terephthalate (DMT), which is then reused as a chemical raw material. However, this method is complex, making it difficult to ensure the purity of the product, and limiting the uses of the recycled product.

[0006] Spandex is a general term for polyurethane elastic fibers and is currently the most widely used elastic fiber. Spandex is a block copolymer consisting of soft segments and hard segments. The soft segments are generally composed of flexible chains and are obtained by the reaction of polyols such as polyethers, polyesters, and terminally hydroxy-sealed polybutadienes with polyisocyanates that link these polyols. The hard segments are composed of chains with excellent crystallinity and are generally obtained by the reaction of polyisocyanates with low molecular weight polyols or low molecular weight amine-based chain extenders.

[0007] The dominant spandex on the market is polyether-based spandex produced by the dry process, with polytetrahydrofuran etherdiol (PTMEG), diphenylmethane diisocyanate (MDI), and amine-based chain extenders as the main raw materials. A polyurethane urea solution is produced by a two-stage polymerization reaction, and the spinning stock is prepared by adding the necessary additives. Spandex fibers are obtained by dry spinning through a spinning duct. This method, by using PTMEG as a soft segment, yields spandex fibers with balanced performance, generally possessing high elongation and tensile modulus that generally meets the requirements of everyday clothing. However, high cost and the inability to use recycled materials are challenges.

[0008] Spandex is rarely used as a standalone fabric in practical applications; it is generally used in blends with other fibers. The current mainstream is polyether-based spandex, dry-spun from PTMEG and polyisocyanate. While typical spandex is dyed with disperse dyes or acid dyes, in practical use, the dyeing rate and colorfastness are poor, resulting in color differences and "white spots" (dew whites) after single-bath dyeing with other fibers, significantly affecting the appearance of the textile product. This is because the molecular structure of spandex is mainly composed of a polyether portion with low polarity and a polyurethane or polyurethane urea group portion with high polarity. The polyether portion of mainstream products is a PTMEG residue, which belongs to the amorphous region in the microphase separation structure, has a loose structure, imparts elasticity to spandex, and is the main dyeing site for disperse dyes, but its interaction with the dye is weak. On the other hand, while the polyurethane or polyurethane urea group portion can theoretically be dyed with acidic, neutral, acid-mediated, and disperse dyes via hydrogen bonds and coordination bonds, this portion is a crystalline region with densely packed molecular chains. As a result, dye molecules do not easily diffuse into the crystalline region, and the dyeing rate is significantly reduced.

[0009] Through years of research, the inventors have discovered that by using a polyether ester polyol having an aromatic group-polyether block as the soft segment of spandex, a spandex with high elongation and high elastic recovery can be obtained. Furthermore, by introducing a small amount of low-molecular-weight diol structure into the block structure of the above polyether ester polyol, the elastic modulus and elastic recovery rate of the spandex can be adjusted. In addition, the structure of this polyether ester polyol is similar to that of general polyester, offering the possibility of using recovered polyester as a raw material for spandex. Normally, the production of this type of polyether ester polyol is based on the idea of ​​reacting a dicarboxylic acid having an aromatic group with a polyether diol, but the process of obtaining terephthalic acid from recovered polyester is complex, energy-intensive, and difficult to purify.

[0010] Therefore, the present invention aims to provide a method for producing a polyether ester polyol suitable for spandex production using recovered polyester, and further for producing easily dyeable spandex using the polyether ester polyol, and to optimize the production process of the polyether ester polyol and the performance of the product. [Overview of the project] [Problems that the invention aims to solve]

[0011] To solve the above problems, the present invention provides a method for producing a polyether ester polyol suitable for the production of spandex using polyester as a raw material, a polyether ester polyol produced by the said method, and polyurethane elastic fibers, nonwoven fabrics, membranes, and elastomers produced using the said polyether ester polyol, and methods for producing the same. Specific embodiments are as follows. [Means for solving the problem]

[0012] In one embodiment, the present invention provides a method for producing a polyether ester polyol, the method characterized by comprising the following steps.

[0013] Step 1) Polyetherdiol and polyester are added to the reaction vessel as raw materials. Here, the polyester contains an aromatic dibasic acid-polyol ester structure, the degree of polymerization of the polyetherdiol is 2 to 20, the molecular weight is 100 to 1000, and the molar ratio of the polyetherdiol to the aromatic groups in the polyester is greater than 1.05:1.

[0014] Step 2) The reaction vessel is heated to the reaction temperature to carry out the transesterification reaction, and the low molecular weight polyol produced in the transesterification reaction is removed by vacuum distillation to obtain a polyether ester polyol. Here, the reaction temperature is higher than the boiling point of the low molecular weight polyol and lower than the boiling point of the polyether diol.

[0015] Optionally, in the above method, the aromatic dibasic acid-polyol ester structure refers to an ester structure formed by an aromatic dibasic acid and a polyol in a polyester. Here, aromatic includes aromatic ring structures and aromatic ring structures. The aromatic ring may be at least one of the following: a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, etc., and the aromatic ring may be at least one of the following: a pyridine ring, a furan ring, a thiazole ring, a pyrimidine ring, etc. Specifically, the aromatic dibasic acid may be one or more of the following: terephthalic acid, phthalic acid, isophthalic acid, biphenyldicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,5-frandicarboxylic acid, terephthalic acid diacetic acid, isophthalic acid diacetic acid, or phthalic acid diacetic acid. The polyol is one or more of diols, triols, and tetraols, preferably a diol, and more preferably one or more of ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 2-methyl-1,3-propanediol, and 3-methyl-1,5-pentanediol.

[0016] Optionally, in the present invention, the polyester containing the aromatic dibasic acid-polyol ester structure may be one or more of the following: polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), copolymer of butanediol adipic acid ester and butanediol terephthalate ester (PBAT), and poly(2,5-franj carboxylate ethylene glycol ester) (PEF).

[0017] Furthermore, the polyester containing the aromatic dibasic acid-polyol ester structure may also be a polyester containing a polyether ester structure, or another common polyester containing a triol or tetraol residue structure. As long as it contains an aromatic dibasic acid-polyol ester structure in its main chain, it can be used as a raw material in the method of the present invention.

[0018] Optionally, the polyether diol may be a homopolymer or copolymer polyether diol produced by condensation polymerization of a C2-C5 low molecular weight diol or ring-opening polymerization of a C2-C5 epoxy compound. Specifically, preferably, it is any one or more of polyethylene glycol (PEG), poly-1,3-propanediol (P3OG), poly-1,2-propanediol (PPG), polytetrahydrofuran (PTG), polyethylene glycol-1,2-propanediol copolymer, and polytetrahydrofuran-3-methyltetrahydrofuran copolymer.

[0019] Optionally, the molar ratio of the aromatic group structure in the polyether diol and the polyester can be calculated by the following formula. JPEG2026524162000001.jpg21139 Here, R Molar ratio of the aromatic group structure in the polyether diol and the polyester, W Molecular weight of the target polyether ester polyol (1000 - 5000), P Molecular weight of the aromatic dibasic acid in the raw material of the polyester, A Average molecular weight of the polyether diol,

[0020] <  Here, the aromatic dibasic acid in the raw material of the polyester refers to the dibasic acid-based raw material that forms the aromatic dibasic acid-polyol ester structure, and examples include terephthalic acid, phthalic acid, 2,5-furandicarboxylic acid, etc. mentioned above.

[0021] The polyether ester polyol obtained by the "method for producing a polyether ester polyol" is characterized by including the structures shown in the following formula (1) and formula (2) and a terminal alcoholic hydroxyl group.

[0022] JPEG2026524162000002.jpg 25132 JPEG2026524162000003.jpg 24128 R1 is an aromatic group, and the mass content of R1 in the repeating unit of formula (1) is 4.5% - 44%. R2 is at least one kind of saturated alkyl group having 2 - 5 carbon atoms, x is 2 - 20, and R3 is the residue of the polyol in the polyester raw material.

[0023] The mass ratio occupied by formula (2) in the structure of the polyether ester polyol is less than 20%, preferably less than 10%.

[0024] The number average molecular weight of the polyether ester polyol is 1000 - 5000.

[0025] The average functionality of the terminal alcoholic hydroxyl groups is 1.95 - 2.00.

[0026] Preferably, the R2 is at least two kinds of saturated alkyl groups having 2 - 5 carbon atoms.

[0027] The above polyether ester polyol can be used not only in the production of spandex but also in the production of other polyurethane - based products. Therefore, the present invention further provides a method for producing polyurethane elastic fibers, non - woven fabrics, films or elastomers by using the above polyether ester polyol as a raw material through solution processing or melt processing. Also provided are polyurethane elastic fibers, non - woven fabrics, films or elastomers obtained by this method.

[0028] On the other hand, the present invention provides an easily - dyed spandex, characterized in that the soft segment of the molecular structure of the spandex contains the repeating unit of the following formula (I).

[0029] JPEG2026524162000004.jpg25132 Here, R1 is an aromatic group structure, and the mass content of R1 in the repeating unit is 4.5% to 44%. R2 is at least one straight-chain saturated alkyl group having 2 to 3 carbon atoms, and x is 2 to 20.

[0030] The proportion of the mass of the repeating units shown in formula (1) to the mass of the spandex soft segments is greater than 2%, preferably greater than 5%, more preferably greater than 10%, and less than 70%, preferably less than 65%.

[0031] Optionally, the soft segment of the spandex molecular structure may further include a polytetramethylene ether (PTMEG) segment.

[0032] In this invention, the soft segment mass refers to the mass of the molecular structure of the portion of spandex remaining after the reaction of the diol-based raw material and diisocyanate, with the terminal hydroxyl groups removed. The diol-based raw material refers to a diol compound that serves as a soft segment raw material for polyurethane molecules, and includes polyether ester polyols as defined in this invention, and optional polytetrahydrofuran ether diols (PTMEG), but does not include low molecular weight diol compounds used as chain extenders.

[0033] The aforementioned high-rebound, thick denier spandex can be manufactured by dry spinning or melt spinning. Specifically, the method for dry spinning is as follows:

[0034] A method for producing easily dyeable spandex, comprising the following steps:

[0035] Step 1) Diol-based raw materials are encapsulated at the ends using diisocyanate raw materials to produce a prepolymer.

[0036] Step 2) Dissolve the prepolymer using a polar solvent to obtain a prepolymer solution.

[0037] Step 3) The prepolymer is chain-extended using a mixed solution of a chain extender and an inhibitor to obtain a polyurethane / polyurea solution.

[0038] Step 4) Add additives to obtain the spinning solution.

[0039] Step 5) The obtained spinning solution is spun using a spinning apparatus to obtain easily dyeable spandex.

[0040] The method for melt spinning is as follows:

[0041] A method for producing easily dyeable spandex, comprising the following steps:

[0042] Step a) The diisocyanate raw material, the diol-based raw material, and the low molecular weight polyol-based chain extender are each added to the reaction vessel.

[0043] Step b) The materials in the reaction vessel are mixed, and the mixture is heated during or after the mixing process to extrude and granulate, thereby obtaining polyurethane particles.

[0044] Step c) The polyurethane particles are dried, additives are added, and then melt-spinned to obtain easily dyeable spandex.

[0045] In one embodiment of the present invention, the diol-based raw material includes a polyether ester polyol having an aromatic group-polyether interlaced structure, and the polyether ester polyol is composed of repeating units shown in formula (1) and terminal alcoholic hydroxyl groups.

[0046] JPEG2026524162000005.jpg25132 Here, R1 is an aromatic group structure, and the mass content of R1 in the repeating unit is 4.5% to 44%. R2 is at least one linear saturated alkyl group having 2 to 3 carbon atoms, and x is 2 to 20 (preferably 3 to 10). The average number of functional groups of the terminal alcoholic hydroxyl groups is 1.95 to 2.00, and the number-average molecular weight of the polyether ester polyol is 800 to 5000, preferably 1000 to 3500, more preferably 1400 to 2500, and most preferably 1500 to 2300.

[0047] Optionally, the viscosity of the polyether ester polyol is set to 90°C and the shear rate to 1s. -1 The poise may be less than 500, preferably less than 200.

[0048] Optionally, the mass ratio of the polyether ester polyol in the diol-based raw material may be greater than 2%, preferably greater than 5%, and more preferably greater than 10%.

[0049] Optionally, the mass ratio of the polyether ester polyol in the diol-based raw material may be less than 70%, preferably less than 65%.

[0050] Optionally, the diol-based raw material may further include other diol compounds that can form soft segments of spandex, i.e., second-order diol-based raw materials. Examples include polyether diols such as polytetrahydrofuran ether diol (PTMEG), polyethylene glycol (PEG), and polypropylene glycol (PPG); polyester diols such as poly(butanediol adipate) (e.g., copolymer polyester diols of adipic acid and mixed diols (ethylene glycol / 1,4-butanediol, ethylene glycol / 1,2-propanediol, 1,6-hexanediol / 2,2-dimethyl-1,3-propanediol)); other polyether ester diols that can form soft segments; or mixtures of at least two of these diol compounds.

[0051] Preferably, the mass of the second type of diol raw material accounts for 30% to 95% of the total diol raw material. That is, a preferred embodiment is to blend the polyol and the second type of diol raw material to obtain a diol raw material for spandex.

[0052] A preferred secondary diol-based starting material is furan ether diol.

[0053] In another embodiment of the present invention, the diol-based raw material comprises a polyether ester polyol having an aromatic group-polyether interlaced structure, wherein the polyol comprises a repeating unit shown in formula (1) and a terminal alcoholic hydroxyl group.

[0054] JPEG2026524162000006.jpg25132 Here, R1 is an aromatic group structure, and the mass content of R1 in the repeating unit is 4.5% to 44%. R2 is at least one linear saturated alkyl group having 2 to 3 carbon atoms, and x is 2 to 20 (preferably 3 to 10). The repeating unit shown in formula (1) accounts for more than 5% of the mass percentage of the polyether ester polyol. The average number of functional groups of terminal alcoholic hydroxyl groups is 1.95 to 2.00, and the number-average molecular weight of the polyol is 800 to 5000, preferably 1000 to 3500, more preferably 1400 to 2500, and most preferably 1500 to 2300.

[0055] Other polyester structures or polyether structures may be present in the polyether ester polyol, and aliphatic structures may be present as modified structures.

[0056] Similarly, the above-mentioned polyether ester polyol can be blended with the above-mentioned second-type diol-based raw material and used as a diol-based raw material for spandex. [Effects of the Invention]

[0057] The present invention provides a method for producing polyether ester polyols, which uses polyester as a raw material and allows for the direct processing of recovered polyester into polyether ester polyols suitable for spandex production. This simplifies the production process of polyether ester polyols for spandex, effectively utilizes recovered resources, and expands the raw material sources for polyurethane elastic fibers.

[0058] Furthermore, the easily dyeable spandex provided by the present invention allows for the spinning of easily dyeable spandex by adding a polyether ester polyol of a specific structure to a diol-based raw material, thereby incorporating a specific aromatic group-polyether interlaced structure into the molecular soft segments of the resulting spandex fibers. Compared to conventional spandex, the easily dyeable spandex of the present invention can improve the dyeing rate and fixation to disperse dyes and acid dyes without impairing the mechanical properties of spandex.

[0059] Furthermore, by adjusting the mass ratio of the aromatic group-polyether interlaced structure within the molecular soft segments of spandex, it is possible to make the spandex have good alkali resistance while possessing sufficient dyeing and adhesion rates. [Modes for carrying out the invention]

[0060] Regarding the recycling of polyester materials, the most common methods currently employed are recovery through melting and pelletizing, or conversion to terephthalic acid (PTA) or dimethyl terephthalate (DMT) through chemical decomposition for reuse as chemical raw materials.

[0061] The inventors have discovered a novel manufacturing method that uses polyester as a raw material, and the resulting polyether ester polyol can be used as a raw material for the soft segment of spandex. This method allows polyester to be used as a direct raw material for polyurethane elastic fibers, expanding the applications of recycled polyester and broadening the raw material sources for spandex.

[0062] Specifically, the present invention provides a method for producing a polyether ester polyol, and a polyether ester polyol obtained by the same method.

[0063] The aforementioned polyether ester polyol comprises structural units represented by the following formulas (1) and (2) and terminal alcoholic hydroxyl groups.

[0064] JPEG2026524162000007.jpg25132JPEG2026524162000008.jpg24128 Here, R1 is an aromatic group structure, and the mass content of R1 in the repeating unit of formula (1) is 4.5% to 44%.

[0065] R2 is at least one saturated alkyl group having 2 to 5 carbon atoms, x is 2 to 20, and R3 is a polyol residue in the polyester raw material.

[0066] The mass ratio of formula (2) in the structure of the polyether ester polyol is less than 20%, preferably less than 10%, and more preferably 0.

[0067] The number-average molecular weight of the aforementioned polyether ester polyol is between 1000 and 5000.

[0068] The average number of functional groups in the aforementioned terminal alcoholic hydroxyl groups is 1.95 to 2.00.

[0069] Unless otherwise specified below, "polyether ester polyol" refers to a material possessing the above-described properties.

[0070] The aromatic group structure in this invention includes an aromatic ring and an aromatic heterocycle. Examples of aromatic rings include at least one such as a benzene ring, naphthalene ring, anthracene ring, or phenanthrene ring. Examples of aromatic heterocycles include at least one such as a pyridine ring, furan ring, thiazole ring, or pyrimidine ring.

[0071] If the aromatic group R1 content is too high, the final polyether ester polyol will have excessive stiffness and viscosity, which is unfavorable for the polyurethane elastic fiber production process. Therefore, the mass content of R1 in the repeating unit of formula (1) should be set to 4.5% to 44%.

[0072] The structure of formula (2) represents the unreacted polyester residue structure during the reaction of the present invention. Since the reaction does not theoretically proceed completely, some structural units derived from the polyester raw material may remain.

[0073] However, by controlling the reaction conditions, the transesterification reaction can be carried out as completely as possible. The structure of formula (2) significantly increases the melting point of the polyether ester polyol and increases intermolecular interactions, resulting in excessive viscosity at the prepolymer stage and preventing the reaction from being completed. Furthermore, the aromatic dibasic acid-polyol ester structure also negatively affects the elastic recovery of the final polyurethane, causing a decrease in the elastic recovery rate and an increase in permanent deformation. Therefore, in this invention, the mass ratio of the structural units of formula (2) is set to less than 20%, preferably less than 10%, and more preferably 0.

[0074] In the present invention, the average number of functional groups in the terminal alcoholic hydroxyl groups of the polyether ester polyol is 1.95 to 2.00, preferably 1.96 to 2.00, and more preferably 1.98 to 2.00.

[0075] As a result, the polyether ester polyol can undergo a smooth end-to-end reaction with isocyanate, and subsequently, the chain extension reaction with small molecule amines or alcohols can proceed appropriately.

[0076] When the average number of functional groups exceeds 2.00, a communal structure is formed during polyurethane production, preventing the formation of linear polyurethane. As a result, gelation occurs during continuous production, hindering continuous operation of spandex manufacturing.

[0077] On the other hand, if the average number of functional groups is too small, the molecular weight of the resulting polyurethane will be low, negatively affecting the performance of the elastic fiber.

[0078] In actual reactions, polyetherdiols may undergo dehydration of their terminal hydroxyl groups during condensation polymerization / ring-opening polymerization, forming double bonds. Furthermore, there are limitations to the reaction efficiency, making it difficult to completely carry out transesterification or condensation reactions. As a result, the average number of functional groups in the final polyether ester polyol generally does not reach the theoretical value of 2.00.

[0079] Here, "average number of functional groups" refers to the average number of moles of hydroxyl groups that can participate in the reaction per mole of polyether ester polyol, and in this invention, it is calculated using the following formula.

[0080] Number of functional groups = 2 × (number of moles of hydroxyl groups) / (number of moles of hydroxyl groups + number of moles of carboxyl groups + number of moles of double bonds) The melting point of the polyether ester polyol of the present invention can be less than 80°C, and preferably it is liquid at room temperature. This prevents solidification during storage or transport, and facilitates continuous industrial operation.

[0081] If solidification is required, heating and melting will be necessary, which will increase energy consumption.

[0082] The inventors have found that polyether ester polyols having the above properties can be used as a substitute for polytetrahydrofuran ether diol (PTMEG) in the raw material for spandex soft segments and exhibit excellent elastic recovery.

[0083] Based on this knowledge, the inventors proposed a method for producing polyether ester polyols using recycled polyester as a raw material. Compared to the conventional reaction between dicarboxylic acid and polyether diol, this method provides a new use for recycled polyester, diversifies the raw materials for spandex, and is also in line with environmental protection principles.

[0084] A specific method for producing the polyether ester polyol according to the present invention includes the following steps.

[0085] Step 1) Polyetherdiol and polyester are added to the reaction vessel as raw materials. The polyester contains an aromatic dicarboxylic acid-polyol ester structure, the degree of polymerization of the polyetherdiol is 2 to 20, preferably 3 to 10, and the molecular weight is 100 to 1000.

[0086] The molar ratio of the polyetherdiol to the aromatic groups in the polyester is greater than 1.05:1.

[0087] Step 2) Heat the reaction vessel to the reaction temperature and carry out the transesterification reaction. Remove the low molecular weight polyol produced by the reaction by vacuum distillation to obtain a polyether ester polyol. The reaction temperature is set to a range that is higher than the boiling point of the low molecular weight polyol and lower than the boiling point of the polyether diol.

[0088] In the method of the present invention, a polyester containing an aromatic group structure and a specific polyetherdiol are used as raw materials, and a polyether ester polyol satisfying the above properties is obtained by a transesterification reaction.

[0089] The polyether ester polyol obtained by this method has an aromatic group-polyether structure linked by ester bonds. Therefore, in this invention, a polyester containing an aromatic group structure is selected, and the aromatic group structure in the polyester is introduced into the polyether ester polyol molecular structure.

[0090] Specifically, examples of polyesters containing aromatic group structures include any general polyester having an aromatic acid ester structure, namely polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), and butanediol adipate-butanediol terephthalate copolymer (PBAT).

[0091] Furthermore, polyesters having an aromatic heterosaccharide ester structure, such as poly(2,5-franciocarboxylate ethylene glycol ester) (PEF), can also be used. These polyesters can be obtained from recycled polyester bottles, polyester fibers, polyester films, etc.

[0092] The polyether chain segments in the polyether ester polyol of the present invention impart elasticity to the molecule and play a role in compensating for the rigidity provided by the aromatic groups. For the resulting spandex to possess sufficient elastic recovery, it is desirable that the length of the polyether chain segments be appropriate.

[0093] If the polyether chain is too short, the viscosity becomes excessive, reducing the ability to operate continuously in mass production and also worsening the elastic recovery properties.

[0094] On the other hand, if the polyether chain is too long, the elastic modulus of spandex decreases.

[0095] Therefore, in the present invention, the molecular weight of the polyether chain raw material is set to a degree of polymerization of 2 to 20, preferably 3 to 10, and a molecular weight of 100 to 1000, preferably 300 to 1000, and more preferably 600 to 900. Specific polyetherdiols are obtained by ring-opening polymerization of epoxy monomers or condensation reactions of small molecule diols, and may be homopolymers from a single monomer or copolymers from multiple monomers. For example, polyetherdiols applicable to the present invention include one or more mixtures of diethylene glycol (DEG), triethylene glycol (TEG), polyethylene glycol (PEG), poly(1,3-propanediol) (P3OG), polypropylene glycol (PPG), and polytetrahydrofuran (PTG). Copolymer diols obtained by copolymerization of tetrahydrofuran with monomers (ethylene oxide, propylene oxide, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, etc.) can also be used.

[0096] The number-average molecular weight of the polyether ester polyol of the present invention should be 1000 to 5000, preferably 1000 to 3500, more preferably 1400 to 2500, and most preferably 1500 to 2300.

[0097] The larger the number-average molecular weight of the polyether ester polyol, the higher its viscosity becomes, making continuous operation on an industrial scale difficult. However, if the molecular weight of the polyol is too low, a larger amount of diisocyanate is required in the synthesis to maintain a constant molecular weight of the polyurethane prepolymer, resulting in a higher urethane group content in the prepolymer. As a result, the interactions between prepolymer molecules become stronger, and the viscosity increases. In addition, the length of the polyurethane soft segments formed at this time is shorter, affecting the recovery performance of the final polyurethane elastic fibers. In a preferred embodiment, the viscosity of the polyether ester polyol of the present invention is 90°C and a shear rate of 1s. -1 The poise may be less than 500, preferably less than 200.

[0098] The method provided in this invention involves transesterifying a polyester containing aromatic groups with a polyetherdiol to produce a polyether ester polyol. Therefore, the molecular weight of the resulting polyether ester polyol can be adjusted by adjusting the molar ratio R of the polyetherdiol to the aromatic groups in the polyester. In the following, "molar ratio R" refers to the molar ratio of the polyetherdiol to the aromatic groups in the polyester.

[0099] The higher the molar ratio R, i.e., the higher the proportion of polyetherdiol in the raw materials, the more terminal hydroxyl groups remain after the low molecular weight polyol residues in the polyester polymer compound are substituted by the polyetherdiol, resulting in a smaller number-average molecular weight of the resulting polyether ester polyol. Conversely, the lower the proportion of polyetherdiol in the raw materials, the larger the number-average molecular weight of the resulting polyether ester polyol. To obtain the effect of molecular weight adjustment, the number of moles of polyetherdiol must be greater than the number of moles of aromatic group structures in the polyester. Theoretically, when transesterification proceeds completely, the polyetherdiol substitutes all the low molecular weight polyol residues in the polyester, and the excess polyetherdiol cleaves the high molecular weight polyester chain to form a polyether ester polyol with a relatively smaller molecular weight. Therefore, the difference between the number of moles of polyetherdiol and the number of moles of aromatic group structures in the polyester corresponds to the number of moles of the final polyether ester polyol. From the above analysis, the formula for calculating the theoretical predicted molecular weight of the final polyether ester polyol is as follows.

[0100] JPEG2026524162000009.jpg16168 [(Mass of polyetherdiol residue + Mass of polyester residue - Mass of low molecular weight polyol produced by transesterification) / (Moles of polyetherdiol residue - Moles of aromatic group structure in polyester) ..... Equation (3)] The molar ratio R of the specific polyetherdiol to the aromatic group in the polyester can be determined by working backward from the above formula. The specific procedure is as follows.

[0101] If the molecular weight of the final obtained polyether ester polyol is W, the molecular weight of the polyether diol is A, and the number of moles of the precipitant is M, then the mass of the polyether diol precipitant is M·A.

[0102] The polyester is obtained by the reaction of an aromatic dibasic acid with molecular weight P and a low molecular weight polyol with molecular weight Q, and the molecular weight of the repeating unit of the polyester is (P + Q - 36). The number of moles of aromatic group structures in the polyester preparation is M / R, and the preparation mass of polyester is (P + Q - 36)·M / R.

[0103] Substituting these into equation (3), we obtain the following equation.

[0104] JPEG2026524162000010.jpg20145

[0105] [W=(MA+(P+Q-36)·M / R) / (MM / R)···Formula (4)] Simplifying equation (4) above, the relationship between the molecular weight W of the polyether ester polyol and the molar ratio R of the dosing agent is: JPEG2026524162000011.jpg21122

[0106] [W=(RA+P-36) / (R-1)...Equation (5)] You can obtain this.

[0107] Based on equation (5), if you want to obtain a polyether ester polyol of a specific molecular weight, the doping molar ratio R can be calculated using the following formula.

[0108] JPEG2026524162000012.jpg19136

[0109] [R=(W+P-36) / (WA)···Equation (6)] As is clear from equation (6), obtaining a polyether ester polyol with a molecular weight W of 1000 to 5000 depends not only on the molar ratio R, but also on the molecular weight P of the aromatic dibasic acid and the molecular weight A of the polyether diol.

[0110] However, in step (1), the number of moles of polyetherdiol is certainly greater than the number of moles of aromatic groups in the polyester. Therefore, in the present invention, the molar ratio of polyetherdiol to aromatic groups in the polyester is greater than 1.05:1, preferably greater than 1.1.

[0111] In step (2), the temperature of the transesterification reaction is controlled to be higher than the boiling point of the low molecular weight polyol produced and lower than the boiling point of the polyetherdiol. This allows the low molecular weight polyol produced by substitution to be removed as much as possible, enabling the transesterification to proceed completely.

[0112] In the transesterification reaction, it is preferable to add a catalyst to accelerate the reaction. The catalyst in this invention is one or more selected from titanium, vanadium, tin, antimony, zirconium, bismuth, and rare earth elements, and is preferably one or more of tetraisopropoxytitanium, tetrabutoxytitanium, dibutyldilaurate, tin octanoate, and bismuth laurate.

[0113] The present invention also provides a method for producing polyurethane products such as polyurethane elastic fibers, nonwoven fabrics, membranes, or elastomers using the above-mentioned polyether ester polyol, or a polyether ester polyol obtained by the above-mentioned method, as a raw material. The method for producing polyurethane may be a two-stage method for synthesizing a prepolymer, or a one-pot method in which all materials are added at once.

[0114] Among these, the two-step method for producing polyurethane includes (1) a step of reacting a polyether ester polyol with a diisocyanate to form a prepolymer, and (2) a step of polymerizing the prepolymer with a chain extender and a chain arrester.

[0115] The one-pot manufacturing method includes (1) the steps of separately supplying a polyether ester polyol, a diisocyanate, and a low molecular weight polyol chain extender, and adding each substance to a reaction vessel, and (2) the steps of mixing the three in the reaction vessel and heating the mixture to cause a reaction (or causing a heating reaction during the mixing process).

[0116] Here, the diisocyanate can be selected from diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (H12MDI), and one or more isomers thereof.

[0117] The chain extender may be either amine-based or alcohol-based. The amine-based chain extender is a diamine having 2 to 30 carbon atoms, and examples include one or more of the following: ethylenediamine, propylenediamine, butanediamine, pentanediamine, methylpentanediamine, methylpropanediamine, hexamethylenediamine, triethylenediamine, benzidine, phenylenediamine, diaminocyclohexane, 1,6-hexanediamine, dopamine, etc.

[0118] Alcohol-based chain extenders include one or more of the following: ethylene glycol, 1,4-butanediol, diethylene glycol, 1,6-hexanediol, 1,3-propanediol, and 1,4-cyclohexanedimethanol.

[0119] The chain inhibitor is a monovalent amine having 2 to 20 carbon atoms, and can be selected from one or more of the following: ethylamine, isopropylamine, n-butylamine, tert-butylamine, hexylamine, dimethylamine, diethylamine, dipropylamine, di-n-butylamine, di-tert-butylamine, diisobutylamine, diisopropylamine, cyclohexylamine, ethanolamine, etc.

[0120] Unless otherwise specified herein, known methods (solution processing or melt processing) for producing polyurethane products such as polyurethane elastic fibers, nonwoven fabrics, membranes, and elastomers using polyetherdiols are also applicable to the present invention.

[0121] For example, polyurethane elastic fibers can be produced by dry spinning of a polyurethane solution (method and apparatus described in Patent Document CN1147628C) or by melt spinning of polyurethane pellets (method described in Patent Document CN1180137C).

[0122] Nonwoven fabrics can be processed by melt-blown or solution electrospinning, and specifically include nonwoven fabrics produced by the melt-blown nonwoven fabric manufacturing method described in Patent Document CN101400838A and the solution electrospinning method described in Patent Document JP2009108422A.

[0123] Polyurethane films can be processed by solution doctor blade coating, dipping coating, melt extrusion, blowing, casting, etc. Specific examples include the doctor blade method described in Patent Document JP2005205787A, the dipping coating method described in WO2015064776A1, the extrusion method described in GB1137520A, the blowing method described in DE2239478A1, and the casting method described in JP2004203933A.

[0124] Elastomers can be processed by extrusion, injection molding, casting, etc. Specifically, polyurethane elastomers can be obtained by the extrusion method described in Patent Document JP1996027376A, the injection method described in US3917792A, and the casting method described in CA1251294A.

[0125] The methods for manufacturing polyurethane products described in these patent documents are incorporated herein by reference.

[0126] The above-described methods for producing polyurethane elastic fibers, nonwoven fabrics, membranes, and elastomers are merely illustrative. In any other form, the polyether ester polyol of the present invention can be used as a diol-based raw material in the production of polyurethane products by any known technology or means.

[0127] The present invention further provides an easily dyeable spandex produced using the above-mentioned polyether ester polyol and a method for producing the same.

[0128] This easily dyeable spandex exhibits good dyeing rates and fixation capabilities for disperse dyes and acid dyes.

[0129] The soft segment of the molecular structure of the aforementioned easily stainable spandex contains repeating units shown in formula (1) below.

[0130] JPEG2026524162000013.jpg25132 Here, R1 is an aromatic group structure, and the mass content of R1 in the repeating unit is 4.5% to 44%.

[0131] R2 is at least one straight-chain saturated alkyl group having 2 to 3 carbon atoms, and x is between 2 and 20.

[0132] The mass of the repeating unit shown in formula (1) is more than 5% of the mass of the soft segment, preferably more than 10%.

[0133] Optionally, the soft segment of the spandex may further include polytetramethylene ether chains (PTMG chains).

[0134] Dyeing with disperse dyes and acid dyes are both processes of diffusion and adsorption of dye molecules that take place in aqueous solutions. The diol-based raw material commonly used in spandex filaments is polytetrahydrofuran (PTMG), and the resulting polyurethane urea polymer exhibits hydrophobicity.

[0135] In contrast, the easily dyeable spandex provided in the present invention has the above formula (1) structure in its molecular structure, and the (R2-O)x portion in the formula increases the hydrophilicity of the molecular chain.

[0136] This structure is introduced into the spandex molecular structure via polyethylene glycol (PEG) and poly(1,3-propanediol) (P3OG), particularly via polyether ester polyols obtained by reacting PEG with aromatic dibasic acids.

[0137] Compared to polytetrahydrofuran, this structure has a higher density of ether-oxygen bonds, and the resulting polyurethane urea polymer exhibits stronger hydrophilicity.

[0138] Therefore, when dyeing with acid dyes and disperse dyes, spandex swells easily in the dye bath, and the intermolecular gaps expand, allowing dye molecules to penetrate the interior of the spandex more easily.

[0139] Furthermore, many acid dyes and disperse dyes are polymer dyes with aromatic ring structures, and strong van der Waals interactions occur between them and the aromatic ring structures derived from polyether ester polyols.

[0140] As a result, dye molecules that penetrate the spandex interact strongly with the polyether ester chains, becoming more stably fixed and exhibiting high dyeing and fixation rates for acid dyes and disperse dyes.

[0141] In order to satisfy the dyeing rate and fixing rate while ensuring that the introduction of the structure of formula (1) does not adversely affect the mechanical properties of spandex, the present invention specifies concrete conditions regarding the structure of formula (1) as described above.

[0142] More preferably, from the viewpoint of dyeing rate and fixation rate, R2 in the repeating unit of formula (1) contained in the soft segment of the easily dyeable spandex is a linear saturated alkyl group having 2 to 3 carbon atoms.

[0143] The fewer carbon atoms in R2, the higher the density of ether-oxygen bonds, which increases the water absorption of spandex and allows dye molecules to penetrate the fiber more easily, thus contributing to improved dyeing rates.

[0144] Since molecules with branched structures have reduced water absorption, the present invention prefers to use a linear saturated alkyl group for R2. Specifically, the (R2-O)x portion is a PEG polyether chain, a P3OG polyether chain, or a copolymer ether chain of ethylene glycol and 1,3-propanediol, and most preferably a C2 linear saturated alkyl group.

[0145] In the molecular structure of the easily dyeable spandex of the present invention, the presence of the structure of formula (1) in a certain proportion in the soft segment improves the dyeing rate and fixation rate of the spandex.

[0146] The mass ratio in the soft segment of the structure of formula (1) is greater than 2%, preferably greater than 5%, more preferably greater than 10%, more preferably greater than 30%, and most preferably greater than 50%.

[0147] Since the polyether ester structure shown in formula (1) does not significantly affect the mechanical properties of spandex, it is possible to moderately increase its proportion in the soft segment.

[0148] However, due to the ester groups contained in this structure, its alkali resistance tends to be slightly lower compared to spandex obtained using polytetrahydrofuran etherdiol (PTMG), which may lead to a decrease in mechanical performance during the dyeing and finishing process.

[0149] Therefore, it is desirable that the mass ratio of the structure of formula (1) in the soft segment is not excessive, and should be less than 80%, preferably less than 70%, and more preferably less than 65%.

[0150] Specifically, by blending spandex made from polyether ester polyols with spandex made from polyether polyols at the raw material stage, prepolymer stage, or polymer stage, alkali resistance can be improved.

[0151] The present invention further provides a method for producing the above-mentioned easily dyeable spandex.

[0152] The spandex can be manufactured by dry spinning or melt spinning, and the dry spinning method includes the following steps. Step 1) A diol-based raw material is sealed using a diisocyanate raw material to obtain a prepolymer. Step 2) Dissolve the prepolymer using a polar solvent to obtain a prepolymer solution. Step 3) The prepolymer is chain-extended using a mixed solution containing a chain extender and a chain arrester to obtain a polyurethane / polyurethane urea solution. Step 4) Add an auxiliary agent to obtain a spinning solution. Step 5) The obtained spinning solution is passed through a spinning apparatus to produce easily dyeable spandex. Compared to conventional spandex dry spinning, the improvements of this invention lie primarily in the change of the diol-based raw material.

[0153] In one embodiment, the diol-based raw material includes a polyether ester polyol having an aromatic group-polyether block structure, wherein the polyol is composed of a repeating unit of formula (1) and a terminal alcoholic hydroxyl group.

[0154] JPEG2026524162000014.jpg25132 Here, R1 is at least one aromatic ring or aromatic heterocycle, and its mass content in the repeating unit is 4.5% to 44%.

[0155] R2 is at least one linear saturated alkyl group having 2 to 3 carbon atoms, and x is 2 to 20, preferably 3 to 10.

[0156] The average number of functional groups of terminal alcoholic hydroxyl groups is 1.95 to 2.00, and the number-average molecular weight of the polyether ester polyol is 800 to 5000, preferably 1000 to 3500, more preferably 1400 to 2500, and most preferably 1500 to 2300.

[0157] Furthermore, the viscosity of the polyether ester polyol is 90°C and a shear rate of 1s. -1 The pressure is less than 500 poise, preferably less than 200 poise.

[0158] In addition to the methods described above, the polyether ester polyol can also be produced by a condensation reaction or transesterification reaction between an aromatic dibasic acid, an esterified or acid anhydride of the acid, and a polyether diol.

[0159] In one embodiment, the esterified product is obtained by reacting an aromatic dibasic acid with a monohydric alcohol with a boiling point of less than 150°C (e.g., methanol, ethanol, n-butanol, n-hexanol, etc.). This allows the alcohol produced to be easily removed by distillation in subsequent esterification or transesterification reactions. Methanol or ethanol are preferred as the small molecule alcohol.

[0160] Furthermore, using the esterified form of an aromatic dibasic acid rather than its equivalent allows the transesterification reaction with polyetherdiols to be carried out under milder conditions, which is advantageous in terms of manufacturing process design.

[0161] In order to allow the dye molecules to easily penetrate into the spandex, it is preferable that the polyetherdiol is at least one type containing a linear saturated alkyl group having 2 to 3 carbon atoms.

[0162] The high density of ether oxygen bonds increases the hydrophilicity of the polyether chains, allowing spandex to swell more easily during dyeing with acid dyes and disperse dyes, expanding the intermolecular gaps and making it easier for dye molecules to penetrate the fiber.

[0163] Specifically, the polyetherdiol is polyethylene glycol (PEG), poly(1,3-propanediol) (P3OG), or a copolymer etherdiol of ethylene glycol and 1,3-propanediol, and is preferably PEG.

[0164] PEG has a high ether oxygen bond density, which imparts excellent hydrophilicity to spandex and facilitates the internal penetration of dye molecules.

[0165] The aforementioned aromatic dibasic acid is selected from one or more of the following: terephthalic acid, isophthalic acid, phthalic acid, biphenyldicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,5-franzicarboxylic acid, p-phenylacetic acid, m-phenylacetic acid, and o-phenylacetic acid.

[0166] Acid dyes and disperse dyes are often large molecules containing aromatic rings, resulting in strong van der Waals interactions between them and the aromatic ring structure introduced into the polyether ester polyol.

[0167] As a result, dye molecules that penetrate the spandex undergo stronger interactions with the polyether chains and become stably fixed within the molecule. Therefore, due to the synergistic effect of the polyether chains and aromatic ring structure, spandex with a polyether-aromatic ring structure exhibits higher dyeing and fixation rates compared to conventional spandex.

[0168] By using a polyether ester polyol having an aromatic group-polyether block structure as a soft segment raw material for spandex, the structure of formula (1) can be introduced into the spandex molecule.

[0169] Since the aforementioned polyether ester polyol contains an ester group, using it alone as a diol-based raw material results in lower alkali resistance compared to polyether-type spandex.

[0170] Therefore, it is necessary to limit the mass ratio in the soft segment of the aromatic group-polyether block structure.

[0171] Specifically, by co-mixing polyether ester polyol spandex and polyether-type spandex in the form of diol-based raw materials, prepolymers, or polymers, the alkali resistance of polyether ester-type spandex can be improved.

[0172] Taking blending at the diol-based raw material stage as an example, in order to increase the dyeing rate and fixing rate, the mass ratio of polyether ester polyol in the diol-based raw material is more than 2%, preferably more than 5%, more preferably more than 10%, more preferably more than 20%, even more preferably more than 30%, even more preferably more than 40%, and most preferably more than 50%.

[0173] On the other hand, in order to ensure alkali resistance, the mass ratio of polyether ester polyol should be less than 80%, preferably less than 70%, and more preferably less than 65%.

[0174] Optionally, the diol-based raw material may include, in addition to the polyether ester polyols mentioned above, other diol compounds (second-type diol-based raw materials) that can be used as soft segments of spandex.

[0175] Examples of these second-type diol-based raw materials include polyether diols such as polytetrahydrofuran ether diol (PTMG), polyethylene glycol (PEG), and polypropylene glycol (PPG), or poly(butanediol adipate) ester diols, copolymer polyester diols of adipic acid and mixed diols (e.g., ethylene glycol / 1,4-butanediol, ethylene glycol / 1,2-propanediol, 1,6-hexanediol / 2,2-dimethylpropanediol-1,3), other polyether ester diols that can be used as soft segments of spandex, or mixtures of two or more of these.

[0176] To ensure alkali resistance of spandex, it is preferable to select a polyetherdiol as the second type diol raw material, and the most preferred is polytetrahydrofuran etherdiol.

[0177] The mass ratio of the second type of diol raw material accounts for 30-98%, preferably 35-90%, of the total diol raw material.

[0178] In other words, in a preferred embodiment, a polyether ester polyol and a second type diol-based raw material are co-mixed to obtain a diol-based raw material for spandex.

[0179] The method of co-mixing at the prepolymer or polymer stage is the same as described above, and therefore will not be described in detail here.

[0180] In order to ensure the alkali resistance of spandex, in another embodiment of the present invention, the diol-based raw material is made to include a polyether ester polyol having an aromatic group-polyether block structure.

[0181] The polyether ester polyol contains the repeating unit shown in formula (1) and terminal alcoholic hydroxyl groups.

[0182] JPEG2026524162000015.jpg25132 Here, R1 is at least one aromatic ring or aromatic heterocycle, and its mass content in the repeating unit is 4.5-44%.

[0183] R2 is at least one linear saturated alkyl group having 2 to 3 carbon atoms, and x is 2 to 20, preferably 3 to 10.

[0184] The mass ratio of the repeating units of formula (1) in the polyether ester polyol is greater than 2%, preferably greater than 5%, and more preferably greater than 10%.

[0185] The average number of functional groups of terminal alcoholic hydroxyl groups is 1.95 to 2.00, and the number-average molecular weight of the polyether ester polyol is 800 to 5000, preferably 1000 to 3500, more preferably 1400 to 2500, and most preferably 1500 to 2300.

[0186] Unlike the above embodiment, this embodiment balances the dyeability and alkali resistance of spandex by reducing the proportion of the cyclic structure shown in formula (1) in the polyether ester polyol.

[0187] In preferred embodiments, the mass ratio of the cyclic structure of formula (1) is greater than 5%, preferably greater than 10%, more preferably greater than 30%, most preferably greater than 50%, and less than 80%, preferably less than 70%, and more preferably less than 65%.

[0188] The remaining portion of the polyether ester polyol may contain other polyester structures, polyether structures, or aliphatic structures as modified structures. To ensure the mechanical properties of spandex, a polyether structure is preferred, and the most preferred is a polytetramethylene ether structure.

[0189] Similarly, the above-mentioned polyether ester polyol may be mixed with the aforementioned second-type diol-based raw material to form a diol-based raw material for spandex.

[0190] In the method for producing easily dyeable spandex according to the present invention, the diisocyanate raw material in step 1) is selected from one or more of the following: diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (H12MDI), and their isomers.

[0191] The polar solvent in step 2) is at least one of N,N-dimethylformamide (DMF) or N,N-dimethylacetamide (DMAc).

[0192] The chain extender in step 3) may be either amine-based or alcohol-based. The amine-based chain extender is a diamine having 2 to 30 carbon atoms, and examples include one or more of the following: ethylenediamine, propylenediamine, butanediamine, pentanediamine, methylpentanediamine, methylpropanediamine, hexamethylenediamine, triethylenediamine, benzidine, phenylenediamine, diaminocyclohexane, hexamethylenediamine, and dopamine.

[0193] Alcohol-based chain extenders include one or more of the following: ethylene glycol, 1,4-butanediol, diethylene glycol, 1,6-hexanediol, 1,3-propanediol, and 1,4-cyclohexanedimethanol.

[0194] The chain inhibitor is a monovalent amine having 2 to 20 carbon atoms, selected from one or more of the following: ethylamine, isopropylamine, n-butylamine, tert-butylamine, hexylamine, dimethylamine, diethylamine, dipropylamine, di-n-butylamine, di-tert-butylamine, diisobutylamine, diisopropylamine, cyclohexylamine, ethanolamine, etc.

[0195] The melt spinning method includes the following steps:

[0196] Step a) The diisocyanate raw material, the diol-based raw material, and the small molecule polyol-based chain extender are each added to the reaction vessel.

[0197] Step b) The raw materials in the container are mixed, heated during or after mixing to carry out the reaction, and polyurethane pellets are obtained by extrusion and granulation.

[0198] Step c) The obtained polyurethane pellets are dried, an auxiliary agent is added, and then melt spinning is performed.

[0199] The spandex raw materials (diisocyanates, diol-based raw materials, etc.) used in the melt spinning method described above are similar to those used in the dry spinning method; the only difference is that in step a), only alcohol-based materials are used as chain extenders.

[0200] [Examples] The present invention will be described in more detail below based on examples.

[0201] The methods for measuring the various parameters described herein are as follows:

[0202] 1. Measurement of the average number of functional groups.

[0203] Number of functional groups = 2 × (number of moles of hydroxyl groups) / (number of moles of hydroxyl groups + number of moles of carboxyl groups + number of moles of double bonds) The acid value was measured according to standard HG / T2708-1995. The hydroxyl value is determined according to HG / T2709-1995. The degree of unsaturation was measured according to GB / T12008.6-2010.

[0204] Based on the obtained acid value, hydroxyl value, and degree of unsaturation, the number of moles of end groups in the polyether ester diol is calculated.

[0205] 2.300% tensile stress, fracture strength, and fracture elongation.

[0206] Measurements will be taken in accordance with the Textile Industry Standard FZ / T50006-2013 of the People's Republic of China, "Test Method for Tensile Properties of Spandex Filaments."

[0207] 3. Plastic deformation test.

[0208] One end of the sample is secured to the upper clamp, and the other end is pre-tensioned and secured to the lower clamp so that it is straight in the axial direction.

[0209] The apparatus is started, and the sample is stretched from 0% elongation (L0) to 300% elongation (L1) at a speed of 500 mm per minute, and then returned to 0%. This elongation and recovery process is repeated four times.

[0210] During the fifth 300% elongation, the stress F1 at the 200% elongation point is recorded, and after holding for 30 seconds, the material is returned to 0% elongation. During this recovery process, the recovery stress F2 at the 200% elongation point is recorded.

[0211] After another 30 seconds, the sixth tensile test is performed, and the sample length L2 at the preliminary tension position is recorded.

[0212] Plastic deformation rate = (L2 - L0) / L0 × 100% Here, "5LP200%" is the stress value (F1) at 200% elongation during the 5th tensile test. "5UP200%" indicates the 200% elongation stress value (F2) at the time of recovery from the 5th 300% elongation, and serves as an indicator of the recovery modulus.

[0213] The "plastic deformation rate" represents how much the spandex yarn length increased relative to its original length after being stretched five times.

[0214] Furthermore, "5UP200% / 5LP200%" represents the ratio of the 200% recovery stress to the 200% tensile stress in the fifth tensile cycle.

[0215] 4. Dyeing rate of acid dyes and fixing rate after soap washing.

[0216] Acidic red is used as the acidic dye. The dye concentration in the dye bath before dyeing is A, the concentration after dyeing is B, and the concentration of the washing solution after soap washing is C. The calculation is performed as follows.

[0217] Acid dye dyeing rate=(AB) / A Adhesion rate of acid dyes after soap washing = (ABC) / A 5. Dyeing rate of disperse dyes and fixation rate after soap washing.

[0218] Dispersed orange was used as the disperse dye, with the concentration before dyeing being P, the concentration after dyeing being Q, and the concentration of the washing solution after soap washing being M. Disperse dye dyeing rate = (PQ) / P Residual rate of disperse dyes after soap washing = (PQM) / P 6. Alkali resistance test of spandex yarn.

[0219] A 10 g / L potassium hydroxide aqueous solution is used, and the material is boiled at 100°C for 1 hour. The mechanical properties before and after treatment are then compared.

[0220] The antioxidant 245, the auxiliary dye DH300R or 2462B, and the light stabilizer Tinuvin791 used in the following examples are all commercially available products.

[0221] During the reaction process, the low-molecular-weight polyol is removed as a non-condensable gas, and the volatilization of the low-molecular-weight component in the polyetherdiol results in a lower alcohol-to-acid ratio participating in the actual reaction than the theoretical value.

[0222] Therefore, the molecular weight of the final product obtained will be slightly larger than the theoretical value, but the deviation is within an acceptable range.

[0223] [Example 1] Production of polyether ester polyols with a number average molecular weight of 1200 First, polyethylene terephthalate (PET) was pulverized, and 1.9g of the pulverized PET (208) and 3000g of polyethylene glycol (PEG200) with a number-average molecular weight of 200 were added to the reaction vessel (i.e., the molar ratio was approximately 1.38).

[0224] Three g of zinc acetate and one g of antimony trioxide (Sb2O3) were added as catalysts, and the temperature was gradually raised to 235°C to initiate the transesterification reaction. The temperature was maintained at 235°C until the reaction system became a homogeneous phase, and ethylene glycol was removed from the reaction system by vacuum distillation. This was continued until the amount of ethylene glycol removed approached the theoretical value, and the amount of ethylene glycol vaporized was 650 g.

[0225] As a result, a polyether ester polyol with a molecular weight of 1200 was obtained. This polyether ester polyol is tested at 40°C and a shear rate of 1 s. -1The viscosity was 100 poise, the acid value was 0.3, and it was a pale yellow liquid at room temperature.

[0226] [Example 2] Production of polyether ester polyols with a number average molecular weight of 2100 2428.9g of pulverized polyethylene terephthalate (PET) and 3000g of polyethylene glycol (PEG200) with a number-average molecular weight of 200 were added to the reaction vessel (molar ratio approximately 1.19).

[0227] Three g of magnesium acetate and one g of antimony trioxide were added as catalysts, and the temperature was gradually raised to 235°C to carry out the transesterification reaction. The temperature was maintained at 235°C until the reaction system became homogenized, and ethylene glycol was removed by vacuum distillation, yielding 781.9 g of ethylene glycol, which was close to the theoretical value.

[0228] This yielded a polyether ester polyol with a molecular weight of 2100. 40℃·1s -1 It has a viscosity of 210 poise, an acid value of 0.3, and is a pale yellow liquid at room temperature.

[0229] [Example 3] Production of polyether ester polyols with a number average molecular weight of 3400 2.4g of pulverized PET260 and 3000g of PEG200 were added to the reaction vessel (molar ratio approximately 1.11).

[0230] Three g of zinc acetate and one g of antimony trioxide were added as catalysts, and the transesterification reaction was carried out at 235°C. After the reaction was homogenized, 842.3 g of ethylene glycol was removed by vacuum distillation.

[0231] The obtained product is a polyether ester polyol with a molecular weight of 3400, and is analyzed at 40°C for 1 second. -1 It had a viscosity of 650 poise, an acid value of 0.3, and was a pale yellow liquid at room temperature.

[0232] [Example 4] Production of polyether ester polyols with a number average molecular weight of 1500 1296.5g of pulverized PET and 4203g of PEG (PEG400) with a number-average molecular weight of 400 were added to the reaction vessel (molar ratio approximately 1.57).

[0233] Three g of zinc acetate and one g of antimony trioxide were added as catalysts, and the temperature was raised to 245°C for transesterification. The temperature was maintained at 245°C until the reaction system became homogenized, and ethylene glycol was removed by vacuum distillation. The amount of vaporized product was 418.6 g, which approximated the theoretical value.

[0234] The resulting product is a polyether ester polyol with a molecular weight of 1500, obtained at 40°C for 1 second. -1 Its viscosity was 73.5 poise, its acid value was 0.3, and it was a pale yellow liquid at room temperature.

[0235] [Example 5] Production of polyether ester polyols with a number average molecular weight of 3450 10¹⁹ g of pulverized PET and 4480 g of polytetramethylene glycol (PTG650) with a number-average molecular weight of 650 were added to the reaction vessel (molar ratio approximately 1.30).

[0236] Three g of zinc acetate and one g of antimony trioxide were added as catalysts, and the transesterification reaction was carried out at 245°C. After homogenization, three hundred nine grams of ethylene glycol were removed by vacuum distillation.

[0237] A polyether ester polyol with a molecular weight of 3450 was obtained at 40°C for 1 second. -1 Its viscosity was 35.2 poise, its acid value was 0.3, and it was a pale yellow liquid at room temperature.

[0238] [Example 6] Production of polyether ester polyols with a number average molecular weight of 3500 699g of pulverized PET and 4800.2g of poly(1,3-propanediol) (P3OG1000) with a number-average molecular weight of 1000 were added to the reaction vessel (molar ratio approximately 1.32).

[0239] 3 g of zinc acetate and 1.5 g of antimony trioxide were added as catalysts, and the temperature was raised to 250 °C to conduct transesterification. The reaction was maintained until a homogeneous state was obtained, and 286 g of ethylene glycol was removed by vacuum distillation.

[0240] The obtained product was a polyether ester polyol with a molecular weight of 3500, and had a viscosity of 28.5 poise at 40 °C for 1 s -1 and an acid value of 0.3, and was a pale yellow liquid at room temperature.

[0241] [Example 7] Production of polyether ester polyol with a number average molecular weight of 3480 1137.14 g of ground polybutylene terephthalate (PBT) and 4362.85 g of polytetramethylene glycol (PTG650) with a number average molecular weight of 650 were charged into a reaction kettle (molar ratio of about 1.30)

[0242] 3 g of zinc acetate and 1.5 g of antimony trioxide were added as catalysts, and transesterification was carried out at 260 °C. After homogenization, 465 g of butanediol was distilled off by vacuum distillation.

[0243] A polyether ester polyol with a molecular weight of 3480 was obtained, and had a viscosity of 35.8 poise at 40 °C for 1 s -1 and an acid value of 0.3, and was a pale yellow liquid at room temperature.

[0244] The following Examples [8-10] are those in which polyurethane elastic fibers were produced using the obtained polyether ester polyol.

[0245] [Example 8] Production of polyurethane elastic fiber using the polyether ester polyol of Example 1 100 kg of the polyether ester polyol obtained in Example 1 was charged into a reaction kettle maintained at 45 °C and stirred at a stirring speed of 150 rpm.

[0246] Next, 31 kg of diphenylmethane diisocyanate (MDI) was added, stirred for 5 minutes, and then the temperature was raised to 90°C. The mixture was then reacted at 90°C for 2 hours to obtain the prepolymer.

[0247] The prepolymer was cooled to 50°C and dissolved using 166.72 kg of dimethylacetamide (DMAc).

[0248] Subsequently, a 3.2% amine solution containing 2.40 kg of ethylenediamine and 0.29 kg of diethylamine was added, and the chain extension reaction was carried out by increasing the stirring speed to 300 rpm.

[0249] After the reaction was complete, the necessary antioxidants and auxiliaries were added, and the mixture was aged for 30 hours to obtain a spinning solution with a solid content of 35%.

[0250] This raw material was spun by dry spinning to obtain 40D denier polyurethane elastic fiber PUU-3.

[0251] [Example 9] Production of polyurethane elastic fibers using the polyether ester polyol of Example 6 100 kg of the polyether ester polyol obtained in Example 6 was placed in a reaction vessel maintained at 45°C and stirred at a stirring speed of 150 rpm.

[0252] 16.15 kg of diphenylmethane diisocyanate was added, and after 5 minutes the temperature was raised to 90°C. The mixture was then reacted at 90°C for 2 hours to obtain a prepolymer.

[0253] The prepolymer was cooled to 50°C and dissolved in 147.82 kg of DMAc. A 3.2% amine solution containing 2.13 kg of ethylenediamine and 0.26 kg of diethylamine was added. The stirring speed was increased to 300 rpm to carry out the chain extension reaction. After the reaction, an auxiliary agent was added and the mixture was aged for 30 hours to obtain a spinning solution with a solid content of 35%. PUU-4 with a denier of 40D was obtained by dry spinning.

[0254] [Example 10] Production of polyurethane elastic fibers using the polyether ester polyol of Example 7 100 kg of the polyether ester polyol obtained in Example 7 was placed in a reaction vessel maintained at 45°C and stirred at a stirring speed of 150 rpm.

[0255] 16.20 kg of diphenylmethane diisocyanate was added, and after 5 minutes the temperature was raised to 90°C. The mixture was then reacted at 90°C for 2 hours to obtain a prepolymer.

[0256] After cooling to 50°C, the product was dissolved in 147.89 kg of DMAc, and a 3.2% amine solution containing 2.14 kg of ethylenediamine and 0.27 kg of diethylamine was added. Chain extension was then performed at a stirring speed of 300 rpm.

[0257] After the reaction was complete, antioxidants and auxiliaries were added, and the mixture was aged for 30 hours to obtain a spinning solution with a solid content of 35%. Dry spinning yielded PUU-5 with a denier of 40D.

[0258] [Comparative Example 1] Production of polyurethane elastic fibers using polytetrahydrofuran (PTMG) with a number-average molecular weight of 2000. 100 kg of PTMG with a number-average molecular weight of 2000 was added to a reaction vessel at 45°C and stirred at a stirring speed of 150 rpm.

[0259] 22.2 kg of MDI was added, and after 5 minutes the temperature was raised to 90°C. The mixture was then reacted at 90°C for 2 hours to obtain a prepolymer.

[0260] This was cooled to 50°C, dissolved in 155.5 kg of DMAc, and a 3.2% amine solution containing 2.26 kg of ethylenediamine and 0.28 kg of diethylamine was added to carry out the chain extension reaction.

[0261] After the reaction, an auxiliary agent was added and the mixture was aged for 30 hours to obtain a stock solution with a solid content of 35%, which was then dry-spun to obtain PUU-0 with a denier of 40D.

[0262] [Comparative Example 2] Manufacturing of polyurethane elastic fibers using polyethylene glycol with a number-average molecular weight of 1500 100 kg of PEG with a number-average molecular weight of 1500 was placed in a reaction vessel at 45°C and stirred at a stirring speed of 150 rpm.

[0263] 26.5 kg of MDI was added, and after 5 minutes the temperature was raised to 90°C and the mixture was reacted for 2 hours to obtain a prepolymer.

[0264] The mixture was cooled to 50°C, dissolved in 161 kg of DMAc, and chain extension was performed by adding a 3.2% amine solution containing 2.32 kg of ethylenediamine and 0.28 kg of diethylamine.

[0265] After adding auxiliary agents and aging for 30 hours, PUU-1 with a denier of 40D was obtained by dry spinning.

[0266] [Comparative Example 3] Production of polyurethane elastic fibers using polypropylene glycol with a number-average molecular weight of 2000 100 kg of PPG with a number-average molecular weight of 2000 was added to a reaction vessel at 45°C and stirred at a stirring speed of 150 rpm.

[0267] 21.98 kg of MDI was added, and after 5 minutes the temperature was raised to 90°C and reacted for 2 hours to obtain a prepolymer.

[0268] The prepolymer was cooled to 50°C, dissolved in 155.24 kg of DMAc, and a 3.2% amine solution containing 2.24 kg of ethylenediamine and 0.28 kg of diethylamine was added. The chain extension reaction was carried out at a stirring speed of 300 rpm.

[0269] After adding an auxiliary agent and allowing it to mature for 30 hours, PUU-2 with a denier of 40D was obtained by dry spinning.

[0270] [Comparative Example 4] Production of polyether ester polyols with a number average molecular weight of 1200 First, polyethylene terephthalate (PET) was pulverized, and 2602.4 g of the pulverized PET and 3000 g of polyethylene glycol (PEG200) with a number average molecular weight of 200 were charged into a reaction kettle.

[0271] As catalysts, 3 g of zinc acetate and 1.5 g of antimony trioxide (Sb2O3) were added, and the temperature was gradually raised to 235°C to initiate the transesterification reaction. The temperature of 235°C was maintained until the reaction system became a homogeneous phase, and ethylene glycol in the reaction system was distilled off by vacuum distillation, and a total of 681 g of ethylene glycol was distilled out.

[0272] The obtained product was a polyether ester diol with a molecular weight of 1200.

[0273] This polyether ester diol was solid at 40°C, had a melting point of 60°C, and an acid value of 0.3. The molar ratio of the ethylene glycol ester structure in this product was 20%.

[0274] [Comparative Example 5] Production of polyurethane elastic fiber using the polyether ester polyol of Comparative Example 4 100 kg of the polyether ester polyol obtained in Comparative Example 4 was charged into a reaction kettle maintained at 90°C, and stirring was started at a stirring speed of 150 rpm.

[0275] When 31 kg of diphenylmethane diisocyanate was added to carry out the prepolymerization reaction, the viscosity of the prepolymer became excessive at the 57th minute of the reaction, and the reaction could not be continued, and the prepolymerization reaction could not be completed.

[0276] According to the above test method, the measurement results of the polyurethane elastic fibers (i.e., spandex yarns) obtained in Examples 8, 9, 10 and Comparative Examples 1, 2, 3 were summarized in the following table.

[0277] As is clear from the data in the table above, the polyurethane elastic fiber obtained using the polyether ester polyol of the present invention exhibits significantly improved tensile stress and breaking strength compared to polyurethane elastic fiber made from polyethylene glycol, and shows performance equivalent to or better than that of commonly used polytetramethylene glycol (PTMG)-based polyurethane elastic fiber.

[0278] This confirmed that the yarn meets sufficient performance requirements for use as a spandex yarn for clothing.

[0279] Furthermore, the polyurethane elastic fiber using the polyether ester polyol of the present invention exhibits a clearly reduced plastic deformation rate and, as is evident from the 5UP200% value, a greater recovery stress (recovery modulus). This means that the elastic recovery force is high and the fabric retains its shape well.

[0280] Therefore, the polyether ester polyol production method of the present invention makes it possible to obtain a polyether ester polyol for spandex that has performance comparable to conventional polytetramethylene glycol, while utilizing used polyester as a raw material.

[0281] The spandex fibers obtained using this polyol exhibit excellent mechanical properties, effectively improving wearability in clothing applications.

[0282] Therefore, the method of the present invention simultaneously achieves the expansion of applications for recycled polyester materials and the diversification of spandex raw materials.

[0283] The spinning solutions (35% solids) obtained in Examples 8, 9, 10 and Comparative Examples 1, 2, 3 were diluted to 20%, and polyurethane thin-film gloves were manufactured by dipping.

[0284] Membrane fragments were cut from the palm portion of the obtained gloves and designated as PUU-F3, PUU-F4, PUU-F5 (Example), PUU-F0, PUU-F1, and PUU-F2 (Comparative Example).

[0285] The manufacturing procedure for thin film samples is as follows:

[0286] The hand mold was slowly immersed in a dilution solution tank, and after rotating the hand mold during removal to ensure uniform film thickness, it was dried in a drying oven. After drying, the glove was peeled off the hand mold to obtain a polyurethane thin-film glove with a film thickness of approximately 150 μm.

[0287] The palm-sized thin film was cut into test pieces measuring 6 mm in width and 10 cm in length, and its mechanical properties were measured.

[0288] As is clear from the table above, the thin-film products (gloves) manufactured using the polyether ester polyol of the present invention exhibit significantly improved tensile stress and breaking strength compared to thin-film products made from polyethylene glycol or polypropylene glycol, and show mechanical properties comparable to or exceeding those of thin-film products derived from polytetramethylene glycol.

[0289] This confirmed that the material fully meets the mechanical properties required for an elastic thin-film glove.

[0290] Furthermore, the polyurethane thin-film gloves using the polyether ester diol of the present invention have a low rate of plastic deformation and excellent shape retention.

[0291] Furthermore, the high 5UP200% value indicates superior recovery (coverage), allowing the glove to adhere more closely to the hand while simultaneously maintaining sufficient coverage and enabling a thinner glove design.

[0292] This makes it possible to improve coverage while reducing material costs.

[0293] Therefore, the polyether ester polyol obtained by the present invention imparts excellent film mechanical properties as a soft segment of polyurethane thin films and fibers, and realizes a low plastic deformation rate and a high recovery modulus even in thin glove film products.

[0294] As a result, the retention of the product shape is enhanced, contributing to an improvement in the covering property and a reduction in the manufacturing cost.

[0295] The following is a word-for-word Japanese translation of the "Examples 11 to 18" part presented. It is described in a formal style based on the documents submitted to the Japan Patent Office.

[0296] [Example 11] Production of melt-spun spandex using the polyether ester polyol of Example 2 The polyether ester polyol obtained in Example 2, 1,4-butanediol, and diphenylmethane diisocyanate were metered and charged into a twin-screw extruder at molar ratios of 1.2, 2, and 3.2, respectively, and continuous polymerization reaction and extrusion were carried out at 195°C. The obtained melt was granulated with a water pelletizer and dried until the moisture content of the polyurethane particles reached 100 ppm or less. Then, auxiliary agents such as necessary antioxidants and light stabilizers were added, and melt spinning was performed to obtain spandex (TPU-1) with a denier of 20D.

[0297] [Comparative Example 6] Production of melt-spun spandex using polytetramethylene glycol (PTMG) with a number average molecular weight of 2000 Polytetramethylene glycol (PTMG2000) with a number average molecular weight of 2000, 1,4-butanediol, and diphenylmethane diisocyanate were metered and charged into a twin-screw extruder at molar ratios of 1.2, 2, and 3.2, respectively, and continuous polymerization reaction and extrusion were carried out at 190°C. The obtained melt was granulated underwater and dried until the moisture content of the polyurethane particles reached 100 ppm or less. Then, necessary antioxidants, light stabilizers, etc. were added and melt spinning was performed to obtain spandex (TPU-0) with a denier of 20D.

[0298] [Comparative Example 7] Production of melt-spun spandex using polyethylene glycol with a number-average molecular weight of 1500 Polyethylene glycol, 1,4-butanediol, and diphenylmethane diisocyanate with a number-average molecular weight of 1500 were weighed and loaded into a twin-screw extruder in a molar ratio of 1.2, 2, and 3.2, and the polymerization reaction and extrusion were carried out continuously at 190°C. After granulation underwater, the polyurethane particles were dried until the moisture content was 100 ppm or less, and melt spinning was performed with the addition of necessary antioxidants, light stabilizers, etc., to obtain spandex (TPU-2) with a denier count of 20D.

[0299] JPEG2026524162000018.jpg35170 Comparing the mechanical properties of the above comparative example and example, it can be seen that the melt-spun spandex yarn obtained by melt processing using polyether ester as a raw material has significantly higher tensile stress and recovery modulus than that obtained using PTMG as a raw material.

[0300] This demonstrates that the molten spandex of the present invention has similar mechanical properties and advantages to dry spandex produced by solution processing.

[0301] [Example 12] Polyether ester polyols with a number average molecular weight of 1500 are produced from polyethylene glycol with a number average molecular weight of 600 and terephthalic acid. 17 parts by weight of polyethylene glycol (PEG600, number average molecular weight 600) and 2.7 parts by weight of terephthalic acid were added to a reaction vessel, and nitrogen gas was introduced to replace the air in the vessel. Stirring was started at a stirring speed of 150 rpm, and the temperature was raised to 150°C and maintained for 5 hours. The temperature was further raised to 230°C and maintained until the dehydration rate in the system was 90% or more of the theoretical value and the solution was homogeneous. Then, tetraisopropyl titanate was added as a catalyst, and the vacuum was reduced to 2000 Pa. When the acid value was less than 0.5 mg KOH / g, a polyether ester polyol with a number average molecular weight of 1500 was obtained. The average functional score was measured to be 1.98 at 90°C·1s. -1 The viscosity was 25 poise, and it was a liquid at room temperature.

[0302] Furthermore, from the perspective of polyester recycling, the 1500 molecular weight polyether ester polyol in this example can also be manufactured using PEG600 and crushed PET as raw materials in the same manner as in Examples 1 to 6.

[0303] [Example 13] Production of polyurethane elastic fibers using the polyether ester polyol of Example 12

[0304] (*Process conditions, reaction temperature, time, and ingredient amounts are the same as in Example 8) This method yielded a polyurethane elastic fiber (PUU-6) with a denier count of 40D.

[0305] [Example 14] Production of polyurethane fibers using the polyether ester polyol of Example 12 and polytetramethylene glycol with a number average molecular weight of 2000

[0306] (50 kg polyether ester polyol + 50 kg PTMG, same conditions apply below) After adding 1% of the dyeing agent 2462B and allowing it to mature for 30 hours, the spinning solution with a solid content of 35% was dry-spun to obtain PUU-7 with a denier count of 40D.

[0307] [Example 15] Production of polyurethane fibers by co-mixing the polyether ester polyol from Example 12 with two prepolymers obtained from PTMG.

[0308] (The manufacturing conditions, reaction temperature, and chain-expanding process for prepolymers 1 and 2 are the same as described above.) Similarly, 1% of the auxiliary dye 2462B was added and dry spinning was performed to obtain PUU-8 with a denier count of 40D.

[0309] [Example 16] Polyurethane fiber production from a stock solution prepared by mixing 100 kg each of the stock solutions from Example 13 and Comparative Example 1. The two stock solutions were mixed by stirring and static mixing to homogenize them, and dry spinning was performed to obtain PUU-9 with a denier count of 40D.

[0310] [Example 17] Production of polyurethane fibers by a mixture of 10% polyether ester polyol and 90% PTMG in Example 12 The conditions were the same as in Example 14, and PUU-10 with a denier count of 40D was obtained.

[0311] [Example 18] Production of polyurethane fibers by a 65% polyether ester polyol + 35% PTMG mixture in Example 12 The same conditions were used to obtain PUU-11 with a denier count of 40D.

[0312] As is clear from the results in the table above, the easily dyeable spandex yarn obtained by the method of the present invention does not show a significant decrease in mechanical performance compared to conventional polyether-based spandex.

[0313] In other words, it was confirmed that by introducing polyether ester polyols in an appropriate proportion, it is possible to improve dyeability while maintaining the elasticity and strength of spandex.

[0314] The following is a word-for-word Japanese translation of the provided data (in the format of a Japanese patent specification). Numerical values ​​and terminology have been preserved as they appeared in the original text.

[0315] The dyeing performance of polyurethane elastic fibers (i.e., spandex yarns) obtained in Examples 12-18 and Comparative Example 1 was evaluated according to the test method described above. The dyeing results with acid dyes are shown in the table below.

[0316] JPEG2026524162000020.jpg70158

[0317] The staining results for disperse dyes are shown in the table below. As can be seen from the table above (JPEG2026524162000021.jpg70158), the spandex yarn obtained by the method of the present invention shows a significant improvement in both dyeing rate and fixation rate with acid dyes and disperse dyes compared to conventional polyether-type spandex.

[0318] The results of evaluating the alkali resistance of the spandex yarns obtained in Examples 12-18 and Comparative Example 1, according to the same test method, are shown in the table below. As shown in the table above (JPEG2026524162000022.jpg63170), PUU-6, which uses only polyether ester polyols as the soft segment raw material, shows some deterioration in mechanical properties after alkaline treatment (boiling), while mixed soft segment raw materials (PUU-7 to PUU-11) show relatively small changes before and after treatment (boiling).

[0319] Based on the above test results, the easily dyeable spandex provided in the present invention can significantly improve the dyeing rate and fixation rate for acid dyes and disperse dyes while maintaining mechanical performance.

[0320] Furthermore, by adjusting the formulation, deterioration of alkali resistance can be avoided, and the requirements for mechanical performance, dyeability, and alkali resistance required for spandex yarn can be simultaneously met.

Claims

1. Step 1) A polyetherdiol and a polyester are placed in a reaction vessel as raw materials, the polyester containing an aromatic dibasic acid-polyol ester structure, the degree of polymerization of the polyetherdiol being 2 to 20, the molecular weight being 100 to 1000, and the molar ratio of the polyetherdiol to the aromatic group structure in the polyester being greater than 1.05:

1. Step 2) The reaction vessel is heated to the reaction temperature to carry out the transesterification reaction, and the low molecular weight polyol produced by the transesterification reaction is removed by vacuum distillation to obtain a polyether ester polyol. Here, the reaction temperature is set to be higher than the boiling point of the low molecular weight polyol and lower than the boiling point of the polyether diol. A method for producing a polyether ester polyol, characterized by comprising the above steps.

2. The manufacturing method according to claim 1, characterized in that the polyetherdiol is one or more of the following: polyethylene glycol, poly(1,3-propanediol), poly(1,2-propanediol), polytetrahydrofuran, polyethylene glycol-1,2-propanediol copolymer, and polytetrahydrofuran-3-methyltetrahydrofuran copolymer.

3. R=(W+P-36) / (WA) Here, R: Molar ratio of polyetherdiol to aromatic group structure in polyester, W: Target molecular weight of polyether ester polyol (1000-5000) P: Molecular weight of aromatic dibasic acid in polyester, A: Average molecular weight of polyetherdiols, The manufacturing method according to claim 1, characterized in that the molar ratio R of the polyetherdiol and the aromatic group structure in the polyester is calculated by the above formula.

4. A polyether ester polyol obtained by the method described in claim 1, comprising the structure represented by the following formulas (1) and (2) and terminal hydroxyl groups, Here, R １ It is an aromatic group structure, and the mass content in the repeating unit of formula (1) is 4.5 to 44%, R ２ x is at least one saturated alkyl group having 2 to 5 carbon atoms, x is 2 to 20, and R ３ This is a polyol residue in the polyester raw material, The mass ratio of the structure of formula (2) in the polyether ester polyol is less than 20%, preferably less than 10%. The number-average molecular weight of the polyether ester polyol is 1000 to 5000, and the average functionality of the terminal hydroxyl groups is 1.95 to 2.

00. A polyether ester polyol characterized by the following features.

5. The aforementioned R ２ The polyether ester polyol according to claim 4, characterized in that it contains at least two saturated alkyl groups having 2 to 5 carbon atoms.

6. A readily stainable spandex, wherein the soft segment of its molecular structure contains repeating units represented by the following formula (1): Here, R １ R2 is an aromatic group structure, with a mass content of 4.5-44% in the repeating unit, R2 is at least one linear saturated alkyl group having 2-3 carbon atoms, and x is 2-20. A highly stainable spandex characterized in that the mass of the repeating units of formula (1) accounts for more than 2% but less than 70% of the mass of the spandex soft segments.

7. The easily stainable spandex according to claim 6, wherein the soft segment of its molecular structure further comprises a polytetramethylene ether chain segment.

8. A method for producing easily dyeable spandex, comprising the following steps: Step 1) A step of preparing a prepolymer by ending the diol-based raw materials with a diisocyanate raw material. Step 2) Dissolve the prepolymer in a polar solvent to obtain a prepolymer solution. Step 3) A step of extending the chains of the prepolymer using a mixed solution containing a chain extender and a end-terminating agent to obtain a polyurethane / polyurea solution. Step 4) Step of adding an auxiliary agent to obtain a spinning solution, Step 5) A step of obtaining easily dyeable spandex by spinning the obtained spinning solution using a spinning apparatus. The method for producing easily dyeable spandex is characterized in that the diol-based raw material includes a polyether ester polyol having an aromatic group-polyether block structure.

9. The polyether ester polyol is composed of repeating units of the following formula (1) and terminal hydroxyl groups, Here, R １ It has an aromatic group structure, and its mass content in the repeating unit is 4.5 to 44%, R ２ x is at least one linear saturated alkyl group having 2 to 3 carbon atoms, x is 2 to 20 (preferably 3 to 10), and the average functionality of the terminal hydroxyl group is 1.95 to 2.

00. The manufacturing method according to claim 8, characterized in that the number average molecular weight of the polyether ester polyol is 800 to 5000, preferably 1000 to 3500, more preferably 1400 to 2500, and most preferably 1500 to 2300.

10. The manufacturing method according to claim 9, characterized in that the mass ratio of the polyether ester polyol in the diol-based raw material is greater than 5% and less than 70%.

11. The manufacturing method according to claim 9, characterized in that the diol-based raw material further comprises one or more of the following: polytetrahydrofranziol, polyethylene glycol, polypropylene glycol, poly(adipic acid-butanediol)diol, or copolymer polyester diol of hexanediol and a mixed diol.

12. The diol-based raw material comprises a polyether ester polyol having an aromatic group-polyether block structure, wherein the polyol comprises a repeating unit of the following formula (1) and a terminal hydroxyl group. Here, R １ is an aromatic group structure, and the mass content in its repeating unit is 4.5 to 44%, and R ２ is at least one of linear saturated alkyl groups having 2 to 3 carbon atoms, x is 2 to 20 (preferably 3 to 10), The repeating units of formula (1) constitute more than 5% but less than 70% by mass of the polyether ester polyol, and the average functionality of the terminal hydroxyl groups is 1.95 to 2.

00. The manufacturing method according to claim 8, characterized in that the number average molecular weight of the polyether ester polyol is 800 to 5000, preferably 1000 to 3500, more preferably 1400 to 2500, and most preferably 1500 to 2300.

13. A method for producing easily dyeable spandex, comprising the following steps: Step a) Step of adding the diisocyanate raw material, the diol-based raw material, and the low molecular weight polyol-based chain extender to the reaction vessels, Step b) A step of mixing the raw materials in a reaction vessel, heating them to cause a reaction during or after mixing, and extruding them to obtain polyurethane particles. Step c) A step of drying the obtained polyurethane particles, adding an auxiliary agent, and performing melt spinning to obtain easily dyeable spandex. The present invention relates to a method for producing easily dyeable spandex, characterized in that the diol-based raw material contains a polyether ester polyol having an aromatic group-polyether block structure.

14. The polyether ester polyol is composed of repeating units of the following formula (1) and terminal hydroxyl groups, Here, R １ It has an aromatic group structure, and its mass content in the repeating unit is 4.5 to 44%, R ２ x is at least one linear saturated alkyl group having 2 to 3 carbon atoms, and x is 2 to 20 (preferably 3 to 10). The average functionality of the terminal hydroxyl groups is 1.95 to 2.00, and the number-average molecular weight of the polyether ester polyol is 800 to 5000, preferably 1000 to 3500, more preferably 1400 to 2500, and most preferably 1500 to 2300. The manufacturing method according to claim 13, characterized in that the mass ratio of the polyether ester polyol in the diol-based raw material is greater than 5% and less than 70%.

15. The polyether ester polyol comprises a repeating unit of the following formula (1) and a terminal hydroxyl group, Here, R1 is an aromatic group structure, with a mass content of 4.5 to 44% in the repeating unit, R2 is at least one linear saturated alkyl group having 2 to 3 carbon atoms, and x is 2 to 20 (preferably 3 to 10). The repeating units of formula (1) exceed 5% by mass ratio of polyether ester polyol. The manufacturing method according to claim 13, characterized in that the average functionality of the terminal hydroxyl groups is 1.95 to 2.00, and the number average molecular weight of the polyether ester polyol is 800 to 5000, preferably 1000 to 3500, more preferably 1400 to 2500, and most preferably 1500 to 2300.

16. A method for producing polyurethane elastic fibers, nonwoven fabrics, membranes, or elastomers by solution processing or melt processing, using a polyether ester polyol obtained by the method for producing a polyether ester polyol according to any one of claims 1 to 3, or the polyether ester polyol according to claim 4, as a raw material.

17. Polyurethane elastic fiber, nonwoven fabric, membrane, or elastomer obtained by the method described in claim 16.

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