Polyether ester polyol, method for preparing the same, and method for preparing polyurethane elastomer using the same

Abstract

The present application relates to a polyether ester polyol, which comprises a repeating structure of formula (1) and a blocked alcoholic hydroxyl group: wherein R1 is selected from at least one of an aromatic ring or an aromatic heterocyclic ring, and the mass content of R1 in the repeating structure of formula (1) is 4.5% to 44%; R2 is selected from at least one of saturated alkane groups having 2 to 5 carbon atoms; x is 2 to 20; the mass percentage of the repeating structure of formula (1) in the polyether ester polyol is greater than 75%; the average functionality of the blocked alcoholic hydroxyl group is 1.95 to 2.00; the number average molecular weight of the polyether ester polyol is 800 to 5000. The present application also relates to a method for preparing the polyether ester polyol, and a method for preparing a polyurethane elastic fiber or elastomer using the polyether ester polyol.

Description

Technical Field

[0001] The present invention relates to the field of polyurethane elastic fibers, and particularly to a polyether ester polyol, a preparation method thereof, and a method for preparing a polyurethane elastomer using the same. Background Art

[0002] Polyurethane, as a block copolymer of soft segments and hard segments, generally has soft segments composed of flexible chain segments. Such soft segments are generally obtained by reacting polyols such as polyethers, polyesters, hydroxyl-terminated polybutadiene, and polyisocyanates for connecting the polyols; the hard segments are composed of segments with excellent crystallization performance, and such hard segments are generally obtained by reacting polyisocyanates with small molecule polyols and small molecule amine chain extenders. Both the soft segment structure and the hard segment structure have an impact on the properties of polyurethane. Generally speaking, during the deformation process of polyurethane, the soft segments will be forced to have internal orientation along the deformation direction. The flexibility of the soft segments enables the soft segment phase of polyurethane to have a large entropy elasticity during use, with an inherent driving force to spontaneously return to the initial most disordered state, making polyurethane have resilience.

[0003] Spandex, that is, polyurethane fiber, its mechanical properties can be characterized by multiple dimensions such as tensile modulus, recovery modulus, elongation at break, breaking strength, stress retention rate, and plastic deformation rate. Among them, the recovery modulus is an important indicator in the application of spandex. The recovery modulus refers to the magnitude of the modulus during the recovery process after the polyurethane fiber is stretched. Fabrics containing spandex require spandex to have a certain recovery modulus, so that the fabric can overcome the resistance between other fibers compatible with it with the assistance of spandex and return to the original shape after experiencing deformation, that is, have a certain shape retention property. Usually, the modulus can be increased, and thus the recovery modulus of spandex can be increased, by reducing the molecular weight of the polyol and increasing the hard segment content. However, these two methods will lead to an increase in the plastic deformation rate of spandex after stretching, that is, spandex is prone to permanent deformation, affecting the service life of clothing.

[0004] An excellent spandex fiber should have strong anti-plastic deformation ability while having a high recovery modulus. For this reason, starting from the raw materials for preparing polyurethane fibers, the present invention attempts to provide a polyether ester polyol and use it to prepare polyurethane elastic fibers, unexpectedly obtaining polyurethane fibers with high recovery modulus and high anti-plastic deformation ability. Summary of the Invention

[0005] The embodiments of the present application provide a polyether ester polyol, a preparation method thereof, a method for preparing a polyurethane elastomer using the same, and the resulting polyurethane elastic fiber, non-woven fabric, film or elastomer.

[0006] The polyether ester polyol of the embodiments of the present application comprises a repeating formula (1) structure and a capped alcohol hydroxyl group:

[0007]

[0008] Wherein R1 is at least one of an aromatic ring and a heteroaromatic ring, and the mass content of R1 in formula (1) is 4.5% to 44%; R2 is at least one of saturated alkyl groups having 2 to 5 carbon atoms; x is 2 to 20;

[0009] The mass percentage of the repeated structure of formula (1) in the polyether ester polyol is greater than 75%;

[0010] The average functionality of the end-capped alcohol hydroxyl groups is 1.95 - 2.00;

[0011] The number-average molecular weight of the polyether ester polyol is 800 - 5000.

[0012] In one embodiment, the melting point of the polyether ester polyol can be lower than 80 °C, and preferably it is in a liquid state at room temperature. In another embodiment, the viscosity of the polyether ester polyol at 90 °C and a shear rate of 1S -1 can be less than 500 poises.

[0013] In one embodiment, the number-average molecular weight of the polyether diol is 100 - 1000, preferably the degree of polymerization of the polyether diol is 2 - 20, and more preferably the degree of polymerization of the polyether diol is 3 - 10.

[0014] In one embodiment, the polyether diol is a copolymer diol obtained by reacting at least two of tetrahydrofuran, ethylene oxide, propylene oxide, 2-methyltetrahydrofuran, or 3-methyltetrahydrofuran.

[0015] In one embodiment, the polyether diol is a mixture of at least two of polytetrahydrofuran, polypropylene glycol, and polyethylene glycol.

[0016] The preparation method of the polyether ester polyol according to the embodiments of the present application may include reacting an aromatic dicarboxylic acid, its esterified product, or its anhydride with a polyether diol, wherein "aromatic" refers to a substance having an aromatic ring or a heteroaromatic ring in its molecular structure. In one embodiment, the aromatic dicarboxylic acid may be selected from one or more of terephthalic acid, isophthalic acid, phthalic acid, biphenyl dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, 2,5-furandicarboxylic acid, terephthalic diacetic acid, isophthalic diacetic acid, and phthalic diacetic acid, and preferably its esterified product is obtained by reacting the aromatic dicarboxylic acid with a monohydric alcohol having a boiling point lower than 150 °C.

[0017] In another embodiment, the number-average molecular weight of the polyether diol can be 100 - 1000, preferably the degree of polymerization of the polyether diol is 2 - 20, and more preferably the degree of polymerization of the polyether diol is 3 - 10.

[0018] The present application also provides a method for preparing polyurethane elastic fibers, non-woven fabrics, films or elastomers using the polyether ester polyol of the present invention as a raw material, and the obtained polyurethane elastic fibers, non-woven fabrics, films or elastomers.

[0019] In a specific embodiment, the polyurethane elastic fibers, non-woven fabrics, films or elastomers are prepared by solution processing or melt processing.

[0020] Beneficial effects:

[0021] The polyether ester polyol provided by the present invention enables the obtained polyurethane fibers to have a higher recovery modulus while also having a lower plastic deformation rate, thereby improving the shape retention and service life of spandex-containing fabrics. At the same time, by using a mixed polyether diol, the properties of spandex can be adjusted as needed. Specific embodiments

[0022] For polyurethane elastic fibers, the most common production method at present is to use polyether diols as raw materials, especially polytetrahydrofuran diol. First, it reacts with diisocyanate to form a prepolymer, and then the prepolymer is chain-extended in the presence of a chain extender and a terminator. In the traditional technology, increasing the recovery modulus will cause an increase in the plastic deformation rate, but the inventor unexpectedly found a polyether ester polyol. When it is used as a raw material for producing polyurethane fibers, the obtained polyurethane fibers not only have a higher recovery modulus but also have a lower plastic deformation rate.

[0023] Specifically, the present invention provides a polyether ester polyol, which contains a repeating structure of formula (1) and a capped alcohol hydroxyl group:

[0024]

[0025] Wherein R1 can be at least one of an aromatic ring or an aromatic heterocyclic ring, and the mass content of R1 in formula (1) can be 4.5% - 44%; R2 can be at least one of saturated alkane groups with 2 - 5 carbon atoms, preferably R2 is selected from at least two of saturated alkane groups with 2 - 5 carbon atoms; x can be 2 - 20; the mass percentage of the repeating structure of formula (1) in the polyether ester polyol can be greater than 75%. When the content of the aromatic group R1 in the polyether ester polyol is too high, it will cause the final polyether ester polyol to be too rigid, resulting in too high viscosity and being unfavorable for the production process of polyurethane fibers; when the content of the aromatic group R1 in the polyether ester polyol is too low, it cannot play the role of improving the recovery modulus of polyurethane fibers.

[0026] The aromatic ring can be at least one of aromatic rings such as benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, etc.; the heteroaromatic ring can be at least one of pyridine, furan ring, thiazole ring, pyrimidine ring, etc. In an alternative embodiment, in addition to the aromatic ring or heteroaromatic ring, R1 further includes 1-4 methylenes.

[0027] In a preferred embodiment, the polyether ester polyol of the present invention has an overall linear chain structure, in which the polyether structure and the aromatic ring are arranged at intervals, thereby improving the ability of the polyurethane fiber to resist plastic deformation; at the same time, the introduction of the aromatic ring (aromatic ring or heteroaromatic ring) also makes the polyurethane elastic fiber have a higher modulus. In a preferred embodiment, the mass percentage of the repeating unit shown in formula (1) in the polyether ester polyol is greater than 95%. In another preferred embodiment, the polyether ester polyol of the present invention is composed of the repeating unit of formula (1) and a capped hydroxyl group.

[0028] According to the present invention, the average functionality of the capped alcohol hydroxyl group of the polyether ester polyol can be 1.95-2.00, preferably 1.96-2.00, more preferably 1.98-2.00, which can ensure that the polyether ester polyol can be smoothly capped with isocyanate and then chain-extended with a small molecule amine or alcohol. If the average functionality is greater than 2.00, when the polyether ester polyol is used as a raw material for preparing polyurethane, it may cause the resulting polyurethane to have a crosslinked structure, thus unable to form a chain-like polyurethane; such polyurethane will form a gel during continuous production, hindering the continuous progress of production. If the average functionality is small, the molecular weight of the resulting polyurethane will also be low, thereby affecting the performance of the polyurethane fiber. In actual reactions, due to the possible dehydration of the terminal hydroxyl groups of the polyether diol to form double bonds during the polycondensation / ring-opening polymerization process, and due to the limitation of the actual reaction effect, the polycondensation reaction or transesterification reaction of the polyether diol to form the polyether ester polyol cannot be completed 100%, so the average functionality of the final polyether ester polyol generally cannot reach 2.00.

[0029] Herein, the "average functionality" represents the average number of moles of alcohol hydroxyl groups that can participate in the reaction per mole of the polyether ester polyol. In the present invention, considering the dehydration of the terminal hydroxyl groups of the polyether diol to form double bonds and the existence of unreacted carboxyl groups, the average functionality of the alcohol hydroxyl groups can be calculated by the following formula:

[0030] Functionality = 2 * moles of alcohol hydroxyl groups / (moles of alcohol hydroxyl groups + moles of carboxyl groups + moles of double bonds)

[0031] The number-average molecular weight of the polyether ester polyol of the present invention can be 800 - 5000, preferably 1000 - 3500, more preferably 1400 - 2500, and most preferably 1500 - 2300. The larger the number-average molecular weight of the polyether ester polyol, the greater its viscosity, and it is difficult to carry out continuous operation on an industrial scale. However, if the molecular weight of the polyether ester polyol is too small, during the polyurethane polymerization reaction, when the molecular weight requirements of the polyurethane prepolymer are consistent, more diisocyanate needs to participate in the synthesis, resulting in a relatively high content of urethane groups in the prepolymer. As a result, the interaction between prepolymer molecules increases, and the viscosity also rises. Moreover, at this time, the length of the soft segment in the formed polyurethane is shorter, which will affect the recovery performance of the final polyurethane fiber.

[0032] In a preferred embodiment, the polyether ester polyol of the present invention has a viscosity less than 500 poise, preferably less than 200 poise, at 90 °C and a shear rate of 1 S -1 -1.

[0033] The melting point of the polyether ester polyol of the present invention can be lower than 80 °C, preferably in a liquid state at room temperature, so as to avoid its solidification during storage or transportation, ensuring continuous industrial operation. Otherwise, it is necessary to heat it to melt, increasing energy consumption.

[0034] The present invention also provides a method for preparing the above polyether ester polyol, which includes subjecting an aromatic dicarboxylic acid, its esterified product or its anhydride to a condensation reaction or a transesterification reaction with a polyether diol.

[0035] According to the method of the present invention, the aromatic dicarboxylic acid can be selected from one or more of terephthalic acid, isophthalic acid, phthalic acid, biphenyl dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, 2,5-furandicarboxylic acid, terephthalic diacetic acid, isophthalic diacetic acid, and phthalic diacetic acid. In one embodiment, its esterified product can be obtained by reacting an aromatic dicarboxylic acid with a small molecule alcohol such as methanol, ethanol, n-butanol, or n-hexanol whose boiling point is lower than 150 °C, so that they can be easily removed by distillation in the subsequent esterification reaction or transesterification reaction; the small molecule alcohol is preferably methanol or ethanol. Moreover, compared with the aromatic dicarboxylic acid, the transesterification reaction between its above esterified product and the polyether diol can be carried out under milder reaction conditions, which is beneficial to the design of the production process. The aromatic dicarboxylic acid applicable to the present invention can be derived from recycled plastics, thus achieving waste recycling and reducing the production cost of polyurethane fibers, which is more in line with the requirements of the current green economy.

[0036] According to the method of the present invention, the degree of polymerization of the polyether diol is preferably 2-20, more preferably 3-10; the number average molecular weight of the applicable polyether diol can be 100-1000, preferably 300-1000, more preferably 600-900. In fact, only when the degree of polymerization and the number average molecular weight of the polyether diol are within the above ranges, the structure in which the polyether segments and the aromatic rings are arranged at intervals can enable the obtained polyether ester polyol to be used for preparing polyurethane, while improving the elastic modulus of the polyurethane fiber and also improving its ability to resist plastic deformation. If the molecular weight of the polyether diol is too low, the viscosity of the prepared polyether ester polyol will be too high, which is not conducive to the continuous progress of the process. If the molecular weight of the polyether diol is too high, it will not play a role in increasing the recovery modulus of the polyurethane fiber. The polyether diol can be synthesized by ring-opening polymerization of epoxy monomers or by polycondensation of small molecule diols; it can be a homopolymer synthesized from a single monomer or a copolymer synthesized from two or more monomers. As an example, the polyether diol applicable to the present invention can be polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, or a copolymer diol obtained by reacting tetrahydrofuran with monomers such as ethylene oxide, propylene oxide, 2-methyltetrahydrofuran or 3-methyltetrahydrofuran.

[0037] From the perspective of the synthesis process, the synthesis routes of polyethylene glycol and polypropylene glycol are relatively short, the production cost is low, and the product price is low. Adding a part of polyethylene glycol and polypropylene glycol as raw materials to polytetramethylene ether glycol can reduce the cost. In addition, compared with polyethylene glycol, polypropylene glycol and polytetramethylene ether glycol, the increase in the ether oxygen bond density will enhance the interaction between the hard and soft segments, achieving the purpose of increasing the tensile modulus and recovery modulus, but it is not beneficial to elongation. Correspondingly, the more carbon atoms are spaced between the ether oxygen bonds, the weaker the interaction between the soft and hard segments of the polyurethane will be, and the elongation of the polyurethane prepared from the obtained polyether ester diol will increase, and the tensile stress and recovery stress will become smaller. Therefore, in actual production, it is preferred to use a mixed polyether diol, which can play a role in reducing the cost and adjusting the performance. For example, a mixture of at least two of polytetramethylene ether glycol, polypropylene glycol, and polyethylene glycol, or a copolymer diol obtained by reacting at least two of tetrahydrofuran, ethylene oxide, propylene oxide, 2-methyltetrahydrofuran or 3-methyltetrahydrofuran. Preferably, the polyether diol is a copolymer diol obtained by reacting tetrahydrofuran with at least one of ethylene oxide, propylene oxide, 2-methyltetrahydrofuran or 3-methyltetrahydrofuran.

[0038] Optionally, in the reaction of an aromatic dicarboxylic acid, its esterified product or its anhydride with a polyether diol according to the method of the present invention, substances such as small molecule diols or aliphatic dicarboxylic acids can also be added to reduce costs or partially modify the polyether ester polyol. Among them, the dosage of the small molecule diol should be strictly controlled because the introduction of too much small molecule diol will cause the viscosity of the final polyether ester polyol to be too high, which is not conducive to the subsequent isocyanate capping reaction and chain extension reaction. Preferably, the dosage of the small molecule diol should be less than 50% by mass of the polyether polyol, preferably less than 20%. The molecular weight of the small molecule diol is less than 200, and it can be one or more of ethylene glycol, propylene glycol, and butanediol.

[0039] The polyether ester polyol of the present invention can be prepared by vacuum esterification or transesterification method, generally carried out in two stages.

[0040] The esterification reaction process of the aromatic dicarboxylic acid in the first stage can be carried out under nitrogen protection, the reaction pressure can be normal pressure, and the temperature can be 150 - 230 °C. The reaction temperature can be gradually increased, and the temperature increase process can adopt a PID control program (proportional integral derivative automatic control program) to increase the temperature. When the whole system becomes homogeneous, it indicates that the reaction in the first stage is completed, because the aromatic dicarboxylic acid cannot be dissolved in the system and exists in a suspended state during the initial feeding. When the water yield of the system reaches more than 90%, the system has also become homogeneous, where "water yield" = water output / (mole number of dicarboxylic acid * 36).

[0041] After the esterification reaction in the first stage is completed, the esterification reaction process in the second stage can be started. Catalysts such as tetra - isopropyl titanate, tetra - butyl titanate, tin oxide, and antimony oxide can be added to the system. The dosage of the catalyst can be 10 - 500 ppm (based on the amount of the polyether ester polyol end product). This catalyst has an obvious catalytic effect on the esterification or transesterification reaction, which can make the acid value of the reaction system easier to decrease. The reaction temperature in the second stage can be 225 - 250 °C. During the reaction process, an acid value detector is continuously used to monitor the progress of the reaction. When the acid value is reduced to the required value (generally required to be 0.5 mgKOH / g), the reaction in the second stage ends, the heating is stopped, and after the temperature is reduced to a suitable temperature, the material is discharged. The suitable temperature is usually below 90 °C.

[0042] The dosage ratio of the aromatic dicarboxylic acid and the polyether diol can be determined according to the molecular weight of the polyether ester polyol and the type of the aromatic dicarboxylic acid, and the alcoholic hydroxyl groups of the polyether diol are in excess relative to the reactive groups of the aromatic dicarboxylic acid. For a certain polyether diol and aromatic dicarboxylic acid, the more the dosage of the polyether diol, the lower the molecular weight of the finally prepared polyether ester polyol.

[0043] The present invention also provides a method for preparing polyurethane products such as polyurethane elastic fibers, non-woven fabrics, films or elastomers using the above polyether ester polyol or the polyether ester polyol prepared by the above method as a raw material. The preparation method of polyurethane can adopt the two-step method of synthesizing prepolymers or the one-pot method of feeding materials together.

[0044] Among them, the method for preparing polyurethane by the two-step method includes the following steps: (1) reacting the polyether ester polyol with a diisocyanate to form a prepolymer; and (2) polymerizing the prepolymer with a chain extender and a chain terminator. The method for preparing polyurethane by the one-pot method includes the following steps: (1) separately feeding the polyether ester polyol, the diisocyanate and the small molecule polyol chain extender, that is, adding each material into the reaction vessel respectively; (2) mixing the polyether ester polyol, the diisocyanate and the small molecule polyol chain extender in the reaction vessel, heating the mixture for reaction, or heating during the mixing process. The diisocyanate can be selected from one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate and its isomers. The chain extender can adopt an amine or alcohol chain extender. Among them, the amine chain extender can be a diamine with 2 to 30 carbon atoms, for example, it can be selected from one or more of ethylenediamine, propylenediamine, trimethylenediamine, pentamethylenediamine, methylpentamethylenediamine, methylpropylenediamine, hexamethylenediamine, triethylenediamine, xylylenediamine, phenylenediamine, dicyclohexylamine, hexamethylenediamine, dopamine; the alcohol chain extender can be one or more of common chain extenders such as ethylene glycol, 1,4-butanediol, diethylene glycol, 1,6-hexanediol, 1,3-propanediol, 1,4-bis(hydroxymethyl)cyclohexane. The chain terminator can be a primary amine with 2 to 20 carbon atoms, and can be selected from one or more of ethylamine, isopropylamine, n-butylamine, tert-butylamine, hexylamine, dimethylamine, diethylamine, dipropylamine, di-n-butylamine, di-tert-butylamine, diisobutylamine, diisopropylamine, cyclohexylamine or ethanolamine.

[0045] Unless otherwise specified in this specification, the corresponding operating conditions in the existing methods for preparing polyurethane products such as polyurethane elastic fibers, non-woven fabrics, films, and elastomers using polyether diols, such as solution processing or melt processing methods, can be applied to the present invention. For example, polyurethane elastic fibers can be prepared by dry spinning of a polyurethane solution using the methods and equipment described in patent document CN1147628C, or by melt spinning of polyurethane chips using the melt spinning method described in patent document CN1180137C; non-woven fabrics can be processed by melt blowing, solution electrospinning, etc. Specifically, the melt blown non-woven fabric manufacturing method described in patent document CN101400838A, and the non-woven fabric prepared by the solution electrospinning method described in patent document JP2009108422A; polyurethane film sheets can be processed by solution scraping, dip coating, melt extrusion, blown film, casting, etc. Specifically, the scraping method described in patent document JP2005205787A, the dip coating method described in patent document WO2015064776A1, the extrusion method described in patent document GB1137520A, the blown film method described in patent document DE2239478A1, and the casting method described in patent document JP2004203933A are used to prepare polyurethane film sheets; elastomers can be processed by extrusion, injection molding, casting, etc. Specifically, the extrusion method described in patent document JP1996027376A, the injection molding method described in patent document US3917792A, and the casting method described in patent document CA1251294A are used to prepare polyurethane elastomers. The production methods of polyurethane products described in the above patent documents are all incorporated into the present invention. The preparation methods of the above-mentioned polyurethane elastic fibers, non-woven fabrics, films, and elastomers are only examples. In addition to the forms mentioned above, the polyether ester polyols of the present invention can be used as diol raw materials to produce polyurethane products by any existing technologies or means.

[0046] Examples

[0047] The present invention will be described in more detail below through examples, and the test methods for the parameters involved are as follows:

[0048] 1. Average functionality:

[0049] Functionality = 2 * moles of alcohol hydroxyl groups / (moles of alcohol hydroxyl groups + moles of carboxyl groups + moles of double bonds).

[0050] Among them, the acid value is measured by the method described in HG / T 2708-1995; the hydroxyl value is measured by the method described in HG / T 2709 / 1995; the unsaturation is measured by the method described in GB / T 12008.6-2010. The corresponding acid value, hydroxyl value, and unsaturation are converted into the molar numbers of the corresponding end groups in the polyether ester diol.

[0051] 2. Tensile stress at 300%, breaking strength, and elongation at break: All in accordance with the "Test Method for Tensile Properties of Spandex Yarn" of the Textile Industry Standard of the People's Republic of China, FZ / T 50006 - 2013.

[0052] 3. Plastic deformation experiment:

[0053] Clamp one end of the prepared specimen into the upper grip, apply a pre - tension to the other end, straighten the specimen axially and clamp it into the lower grip, then start the instrument.

[0054] The specimen is stretched from the 0% elongation point L0 to the 300% elongation point L1 at a speed of 500 mm / min, and then returned to 0% elongation. This stretching - recovery cycle is repeated four times; during the fifth stretching to 300% elongation, record the force value F1 when stretched to 200%, delay for 30 s, and then return to 0% elongation. During this process, record the force value F2 when returned to 200%; delay for 30 s, conduct the sixth stretching, and record the length L2 of the specimen when stretched to the pre - tension point.

[0055] Calculation formula for plastic deformation rate: (L2 - L0) / L0 * 100%

[0056] Among them, "5LP200%" represents the stress value when stretched to 200% elongation in the fifth stretching, that is, F1, and "5UP200%" represents the rebound stress value when returning from stretching to 300% elongation to 200% elongation in the fifth stretching, that is, F2, which can be used to characterize the recovery modulus; "plastic deformation rate" represents the increase ratio of the length of the spandex yarn after 5 stretches compared to the original length; "5UP200% / 5LP200%" represents the ratio of the 200% recovery stress to the 200% tensile stress in the fifth stretching cycle test.

[0057] In addition, the antioxidant mentioned in the following examples is antioxidant 245, the assistant dyeing agent is DH300R or 2462B, and the light stabilizer is Tinuvin 791, all of which are commercially available substances in the market.

[0058] Example 1: Preparation of polyether ester diol with a number - average molecular weight of 1500

[0059] 17 parts by weight of polyethylene glycol PEG600 (number average molecular weight of 600) and 2.7 parts by weight of terephthalic acid were put into a reaction kettle, nitrogen was introduced to displace the air in the reaction kettle. The stirring in the reaction kettle was started, and the stirring speed was 150 rpm. The temperature of the system was raised stepwise to 150 °C and maintained for 5 h; then it was further raised to 230 °C and maintained at this temperature until the water yield rate of the system reached more than 90% of the theoretical value and the solution became homogeneous. Tetraisopropyl titanate was added as a catalyst, and the pressure was gradually reduced to 2000 Pa by vacuum pumping. When the acid value was lower than 0.5 mgKOH / g, a polyether ester diol with a number average molecular weight of 1500 was obtained. After testing, its average functionality was 1.98, and the viscosity at 90 °C for 1S -1 The viscosity was 20 poises, and it was a liquid at room temperature.

[0060] Example 2: The polyether ester diol of Example 1 was used to prepare polyurethane elastic fibers

[0061] 100 kg of the polyether ester diol prepared in Example 1 was added to a reaction kettle that had been kept at a constant temperature of 45 °C. Stirring was started, and the stirring speed was 150 rpm. 26.5 kg of diphenylmethane diisocyanate was added, and after stirring for 5 min, the temperature was raised to 90 °C; it was reacted at 90 °C for 2 h to obtain a prepolymer.

[0062] The prepolymer was cooled to 50 °C, and 161 kg of dimethylacetamide (DMAc) was used to dissolve the prepolymer. Then, an amine solution with a mass concentration of 3.2% containing 2.33 kg of ethylenediamine (EDA) and 0.28 kg of diethylamine (DEA) was added. The stirring speed was increased to 300 rpm for chain extension reaction. After the chain extension reaction was completed, necessary additives such as antioxidants and dyeing assistants were added, and after curing for 30 h, a spinning dope with a solid content of 35% was obtained. The above dope was dry-spun to obtain polyurethane elastic fibers PUU-1 with a denier of 40D.

[0063] Example 3: Preparation of polyether ester diol with a number average molecular weight of 2120

[0064] 17 parts by weight of polyethylene glycol PEG600 (number average molecular weight of 600) and 3.2 parts by weight of terephthalic acid were put into a reaction kettle, nitrogen was introduced to displace the air in the reaction kettle, and the stirring in the reaction kettle was started with a stirring speed of 150 rpm. The temperature of the system was raised stepwise to 150 °C and maintained for 5 h, and then further raised to 230 °C and maintained at this temperature until the water yield rate of the system reached more than 90% of the theoretical value and the solution became homogeneous. Tetraisopropyl titanate was added as a catalyst, and the pressure was gradually reduced to 2000 Pa by vacuum pumping. When the acid value was lower than 0.5 mgKOH / g, a polyether ester diol with a number average molecular weight of 2120 was obtained. After testing, the average functionality was 1.98, and the viscosity at 90 °C for 1S -1 The viscosity was 25 poises, and it was a liquid at room temperature.

[0065] Example 4: The polyether ester diol of Example 3 is used to prepare polyurethane elastic fibers

[0066] Add 100 kg of the polyether ester diol obtained in Example 3 to a reaction kettle that has been heated to a constant temperature of 45°C, start stirring, and the stirring speed is 150 rpm. Add 21.3 kg of diphenylmethane diisocyanate, and after stirring for 5 minutes, raise the temperature to 90°C; react it at 90°C for 2 hours to obtain a prepolymer.

[0067] Cool the prepolymer to 50°C, dissolve the prepolymer with 154.4 kg of dimethylacetamide (DMAc), then add an amine solution with a mass concentration of 3% containing 2.25 kg of ethylenediamine (EDA) and 0.28 kg of diethylamine (DEA), increase the stirring speed to 300 rpm, and carry out a chain extension reaction. After the chain extension reaction is completed, add necessary additives such as antioxidants and dyeing assistants, and then cure for 30 hours to obtain a spinning dope with a solid content of 35%. Carry out dry spinning on the above dope to obtain polyurethane elastic fibers PUU-2 with a denier of 40D.

[0068] Example 5: Preparation of polyether ester diol with a number average molecular weight of 1800

[0069] Put 8.5 parts by weight of polytetrahydrofuran PTG650 (number average molecular weight of 650), 8.5 parts by weight of polyethylene glycol PEG600 (number average molecular weight of 600), and 3.52 parts by weight of terephthalic acid into the reaction kettle, introduce nitrogen to displace the air in the reaction kettle. Start stirring the reaction kettle, and the stirring speed is 150 rpm. Carry out programmed heating of the system, raise the temperature to 150°C, and maintain it for 5 hours; continue to raise the temperature to 230°C and maintain this temperature until the water yield rate of the system reaches more than 90% of the theoretical value, and the solution becomes homogeneous, then add tetra-isopropyl titanate as a catalyst. Gradually evacuate to 2000 Pa, and wait until the acid value is lower than 0.5 mgKOH / g to obtain a polyether ester diol with a number average molecular weight of 1800. After testing, the average functionality is 1.98, and the viscosity at 90°C for 1S -1 is 45 poises, and it is a liquid at room temperature.

[0070] Example 6: The polyether ester diol of Example 5 is used to prepare polyurethane elastic fibers

[0071] Add 100 kg of the polyether ester diol of Example 5 to a reaction kettle that has been heated to a constant temperature of 45°C. Start stirring, and the stirring speed is 150 rpm. Add 23.5 kg of diphenylmethane diisocyanate, and after stirring for 5 minutes, raise the temperature to 90°C; react it at 90°C for 2 hours to obtain a prepolymer.

[0072] Cool the prepolymer to 50°C, dissolve the prepolymer using 157 kg of dimethylacetamide (DMAc), then add an amine solution with a mass concentration of 3.2% containing 2.27 kg of ethylenediamine (EDA) and 0.28 kg of diethylamine (DEA). Increase the stirring speed to 300 rpm and carry out the chain extension reaction. After the chain extension reaction is completed, add necessary additives such as antioxidants and dyeing assistants, and then cure for 30 h to obtain a spinning dope with a solid content of 35%. Carry out dry spinning on the above dope to obtain polyurethane elastic fiber PUU-3 with a denier of 40D.

[0073] Example 7: Preparation of polyether ester diol with a number average molecular weight of 1850

[0074] Put 17 parts by weight of polytetrahydrofuran PTG650 (number average molecular weight of 650) and 3.36 parts by weight of terephthalic acid into a reaction kettle, introduce nitrogen to displace the air in the reaction kettle. Start the stirring of the reaction kettle with a stirring speed of 150 rpm. Carry out programmed heating of the system, heat up to 150°C and maintain for 5 h; continue to heat up to 230°C and maintain this temperature until the water yield rate of the system reaches more than 90% of the theoretical value and the solution becomes homogeneous, then add the catalyst tetraisopropyl titanate. Gradually evacuate to 2000 Pa, and wait until the acid value is lower than 0.5 mgKOH / g to obtain polyether ester diol with a number average molecular weight of 1850. After testing, the average functionality is 1.98, and the viscosity at 90°C for 1S -1 is 38 poises, and it is a liquid at room temperature.

[0075] Example 8: Use the polyether ester diol of Example 7 to prepare polyurethane elastic fiber

[0076] Add 100 kg of the polyether ester diol of Example 7 to a reaction kettle that has been kept at a constant temperature of 45°C. Start stirring with a stirring speed of 150 rpm. Add 23.1 kg of diphenylmethane diisocyanate, stir for 5 min and then heat it up to 90°C; let it react at 90°C for 2 h to obtain a prepolymer.

[0077] Cool the prepolymer to 50°C, dissolve the prepolymer using 157 kg of dimethylacetamide (DMAc), then add an amine solution with a mass concentration of 3.2% containing 2.26 kg of ethylenediamine (EDA) and 0.27 kg of diethylamine (DEA). Increase the stirring speed to 300 rpm and carry out the chain extension reaction. After the chain extension reaction is completed, add necessary additives such as antioxidants and dyeing assistants, and then cure for 30 h to obtain a spinning dope with a solid content of 35%. Carry out dry spinning on the above dope to obtain polyurethane elastic fiber PUU-4 with a denier of 40D.

[0078] Example 9: Preparation of polyether ester diol with a number average molecular weight of 4700

[0079] 17 parts by weight of polyethylene glycol PEG600 (number average molecular weight of 600) and 4.1 parts by weight of terephthalic acid were put into a reaction kettle, nitrogen was introduced to displace the air in the reaction kettle. The stirring of the reaction kettle was started at a stirring speed of 150 rpm. The temperature of the system was raised programmedly to 150 °C and maintained for 5 h; then it was further raised to 230 °C and maintained at this temperature until the water yield rate of the system reached more than 90% of the theoretical value and the solution became homogeneous, and then tetra-isopropyl titanate as a catalyst was added. The pressure was gradually reduced to 2000 Pa, and when the acid value was lower than 0.5 mg KOH / g, a polyether ester diol with a number average molecular weight of 4700 was obtained. After testing, the average functionality was 1.96, and the viscosity at 90 °C for 1 s -1 was 60 poises, and it was a liquid at room temperature.

[0080] Example 10: The polyether ester diol of Example 9 was used to prepare polyurethane elastic fibers

[0081] 100 kg of the polyether ester diol of Example 9 was added to a reaction kettle that had been kept at a constant temperature of 45 °C. Stirring was started at a stirring speed of 150 rpm. 14.3 kg of diphenylmethane diisocyanate was added, and after stirring for 5 min, the temperature was raised to 90 °C; it was reacted at 90 °C for 2 h to obtain a prepolymer.

[0082] The prepolymer was cooled to 50 °C, and 145.5 kg of dimethylacetamide (DMAc) was used to dissolve the prepolymer, and then an amine solution with a mass concentration of 3.2% containing 2.12 kg of ethylenediamine (EDA) and 0.26 kg of diethylamine (DEA) was added. The stirring speed was increased to 300 rpm for chain extension reaction. After the chain extension reaction was completed, necessary additives such as antioxidants and dyeing assistants were added, and after curing for 30 h, a spinning dope with a solid content of 35% was obtained. The above dope was subjected to dry spinning to obtain polyurethane elastic fibers PUU-5 with a denier of 40 D.

[0083] Comparative Example 1: A poly-tetrahydrofuran (PTMG) dope with a number average molecular weight of 2000 was used to prepare polyurethane elastic fibers

[0084] 100 kg of poly-tetrahydrofuran PTMG2000 (number average molecular weight of 2000) was added to a reaction kettle that had been kept at a constant temperature of 45 °C, and stirring was started at a stirring speed of 150 rpm. 22.2 kg of diphenylmethane diisocyanate was added, and after stirring for 5 min, the temperature was raised to 90 °C, and it was reacted at 90 °C for 2 h to obtain a prepolymer.

[0085] Cool the prepolymer to 50°C, dissolve the prepolymer using 155.5 kg of dimethylacetamide (DMAc), then add an amine solution with a concentration of 3.2% containing 2.26 kg of ethylenediamine (EDA) and 0.28 kg of diethylamine (DEA), increase the stirring speed to 300 rpm, and conduct a chain extension reaction. After the chain extension reaction is completed, add necessary additives such as antioxidants and dyeing assistants, and cure for 30 h to obtain a spinning dope with a solid content of 35%. Dry-spin the above dope to obtain polyurethane elastic fiber PUU-0 with a denier of 40D.

[0086] Example 11: Preparation of polyether ester diol with a number average molecular weight of 3140

[0087] Put 17 parts by weight of polyethylene glycol PEG600 (number average molecular weight of 600) and 3.7 parts by weight of naphthalenedicarboxylic acid into the reaction kettle, introduce nitrogen to displace the air in the reaction kettle, start the stirring of the reaction kettle, and the stirring speed is 150 rpm. Carry out a programmed temperature rise for the system, raise the temperature to 150°C and maintain for 5 h; continue to raise the temperature to 230°C and maintain this temperature until the water yield rate of the system reaches more than 90% of the theoretical value, and the solution becomes homogeneous, add the catalyst tetra-isopropyl titanate, and gradually evacuate to 2000 Pa. When the acid value is lower than 0.5 mgKOH / g, obtain naphthalene ring polyether ester diol with a number average molecular weight of 3140. After testing, the average functionality is 1.97, and the viscosity at 90°C for 1S -1 is 80 poises and it is a liquid at room temperature.

[0088] Example 12: Preparation of polyether ester diol with a number average molecular weight of 3250

[0089] Put 17 parts by weight of polyethylene glycol PEG1000 (number average molecular weight of 1000) and 1.9 parts by weight of naphthalenedicarboxylic acid into the reaction kettle, introduce nitrogen to displace the air in the reaction kettle, start the stirring of the reaction kettle, and the stirring speed is 150 rpm. Carry out a programmed temperature rise for the system, raise the temperature to 150°C and maintain for 5 h; continue to raise the temperature to 235°C and maintain this temperature until the system becomes a transparent homogeneous phase, add the catalyst tetra-isopropyl titanate, and gradually evacuate to 2000 Pa. When the acid value is lower than 0.5 mgKOH / g, obtain naphthalene ring polyether ester diol with a number average molecular weight of 3250. After testing, the average functionality is 1.99, and the viscosity at 90°C for 1S -1 is 40 poises and the melting point is 32.1°C.

[0090] Example 13: Preparation of polyether ester diol with a number average molecular weight of 3500

[0091] 17 parts by weight of poly(1,3 - propanediol) PPG950 (number average molecular weight of 950) and 2.1 parts by weight of terephthalic acid were charged into a reaction kettle. Nitrogen was introduced to displace the air in the reaction kettle, and the stirring of the reaction kettle was started at a stirring speed of 150 rpm. The temperature of the system was raised step - by - step. It was raised to 150 °C and maintained for 5 h; then it was further raised to 235 °C and maintained at this temperature until the system became a transparent homogeneous phase. Tetraisopropyl titanate was added as a catalyst, and the pressure was gradually reduced to 2000 Pa by vacuum pumping. When the acid value was lower than 0.5 mgKOH / g, a polyether ester diol with a number average molecular weight of 3500 was obtained. After testing, the average functionality was 1.99, and the viscosity at 90 °C for 1 S -1 was 34 poise, and it was a liquid at room temperature. Comparative Example 2: Preparation of polyether ester diol with a number average molecular weight of 3150

[0092] 17 parts by weight of diethylene glycol DEG (number average molecular weight of 106) and 23 parts by weight of terephthalic acid were charged into a reaction kettle. Nitrogen was introduced to displace the air in the reaction kettle, and the stirring of the reaction kettle was started at a stirring speed of 150 rpm. The temperature of the system was raised step - by - step. It was raised to 150 °C and maintained for 5 h; then it was further raised to 225 °C and maintained at this temperature until the water yield of the system reached more than 90% of the theoretical value and the solution became a homogeneous phase. Tetraisopropyl titanate was added as a catalyst, and the pressure was gradually reduced to 2000 Pa by vacuum pumping. When the acid value was lower than 0.5 mgKOH / g, a polyether ester diol with a number average molecular weight of 3150 was obtained. After testing, the average functionality was 1.99, and the viscosity at 90 °C for 1 S -1 was 2000 poise, and the melting point was 70 °C.

[0093] Comparative Example 3: Using the polyether ester diol of Comparative Example 2 to prepare polyurethane elastic fibers

[0094] 100 kg of the polyether ester diol obtained in Comparative Example 2 was added to a reaction kettle that had been kept at a constant temperature of 45 °C, and the stirring was started at a stirring speed of 150 rpm. After adding 49 kg of dimethylacetamide (DMAc) to dissolve and reduce the viscosity, 17.1 kg of diphenylmethane diisocyanate was added. After stirring for 5 min, the temperature was raised to 90 °C; it was reacted at 90 °C for 2 h to obtain a prepolymer.

[0095] The prepolymer was cooled to 50 °C, and 100 kg of dimethylacetamide (DMAc) was used to dissolve the prepolymer. Then, an amine solution with a concentration of 3.2% containing 2.17 kg of ethylenediamine (EDA) and 0.27 kg of diethylamine (DEA) was added, and the stirring speed was increased to 300 rpm for chain - extending reaction. After the chain - extending reaction was completed, necessary additives such as antioxidants and dyeing assistants were added, and it was cured for 30 h to obtain a spinning dope with a solid content of 35%. The above dope was subjected to dry spinning to obtain polyurethane elastic fibers PUU - 6 with a denier of 40 D.

[0096] According to the above test method, the following parameters of the polyurethane elastic fibers (i.e., spandex filaments) obtained from Test Examples 2, 4, 6 and Comparative Examples 1, 3 were tested, and the test results are summarized in the following table.

[0097]

[0098] As can be seen from the data in the above table, for the polyurethane prepared by using the polyether ester polyol of the present invention to replace the conventionally used polyether diol, the plastic deformation rate of the finally obtained polyurethane fiber decreased significantly; in addition, the ratio of the 200% recovery stress to the 200% tensile stress during the 5th stretching was closer to 1, indicating that the fiber had less energy loss and less hysteresis during the stretching and retraction processes, and could make the fabric more comfortable to wear. From the value of 5UP200%, the polyurethane fiber using the polyether ester diol of the present invention had a greater 200% recovery stress, that is, a greater recovery modulus, indicating a greater resilience and better shape retention of the fabric. Through the comparison of PUU-3 and PUU-4, it can also be seen that compared with the single type of polytetrahydrofuran ether diol, the mixed polyether diol resulted in a decrease in the elongation at break of the polyurethane fiber, while the tensile modulus and recovery modulus increased, playing a role in adjusting the properties of the polyurethane fiber. Different requirements of polyurethane fibers can be produced by adjusting the ratio of the polyether diol.

[0099] The spinning dope in Examples 2, 4, 6, 8, 10 and Comparative Examples 1, 3 was diluted from a solid content of 35% to a solid content of 20%, and then polyurethane film gloves were prepared by dip coating. The corresponding Example film strips PUU-F1, PUU-F2, PUU-F3, PUU-F4, PUU-F5 and the corresponding Comparative Example film strips PUU-F0, PUU-F6 were cut out. The specific preparation steps of the film strips are as follows:

[0100] First, the hand mold was slowly immersed in the tank filled with the diluted dope, then the hand mold was slowly lifted out of the dope tank, and the hand mold was slowly rotated to make the thickness of the dope on the surface of the hand mold uniform. Then the hand mold was dried in an oven, and after drying, the glove was peeled off to obtain a polyurethane film glove with a wall thickness of about 150 microns. To test the mechanical properties of the glove film, the film of the palm part of the glove was cut off and cut into strips with a width of 6 mm and a length of 10 cm to test the mechanical properties.

[0101] The mechanical properties are as follows:

[0102]

[0103] As can be seen from the data in the above table, the polyurethane film gloves prepared with the polyether ester diol prepared by the present invention have the characteristic of low plastic deformation, which makes the shape of the film glove products more stable; from the value of 5UP200%, the polyurethane film sheet prepared with the polyether ester diol of the present invention has a greater 5UP200% recovery force, which will make the glove have better wrapping property. At the same time, on the premise of ensuring the wrapping force, the glove can be made thinner, thereby reducing the raw material cost of the film glove. Through the comparison of PUU-F3 and PUU-F4, it can also be seen that compared with the single type of polytetrahydrofuran ether diol, the elongation at break of the polyurethane film sheet decreases, while the tensile modulus and recovery modulus increase, which also plays a role in adjusting the performance of the polyurethane film sheet.

[0104] The melt-spun spandex filaments prepared from the polyether ester diol of Example 14 and Example 1

[0105] The polyether ester diol of Example 1, 1,4-butanediol and diphenylmethane diisocyanate were respectively metered into a twin-screw extruder at a molar ratio of 1.2:1:2.2, and continuously polymerized and extruded at 195 °C, granulated underwater. After drying to a moisture content of the polyurethane particles below 100 ppm, necessary antioxidants, light stabilizers and other additives were added and melt-spun together to obtain spandex filaments TPU-1 with a denier of 20D.

[0106] The melt-spun spandex filaments prepared from polytetrahydrofuran with a number average molecular weight of 2000 in Comparative Example 4

[0107] Polytetrahydrofuran PTMG2000 (number average molecular weight of 2000), 1,4-butanediol and diphenylmethane diisocyanate were respectively metered into a twin-screw extruder at a molar ratio of 1.2:1:2.2, and continuously polymerized and extruded at 190 °C, granulated underwater. After drying to a moisture content of the polyurethane particles below 100 ppm, necessary antioxidants, light stabilizers and other additives were added and melt-spun together to obtain TPU-0 with a denier of 20D.

[0108]

[0109] From the comparison of the mechanical properties of the above comparative examples and examples, it can be seen that the tensile stress and recovery modulus of the melt-spun spandex filaments processed in the melt form with polyether ester diol as the raw material are significantly higher than those of the melt-processed melt-spun spandex filaments using polytetrahydrofuran as the raw material, and have a lower plastic deformation rate, showing similar mechanical property characteristics and advantages of the dry-process spandex filaments processed in the solvent form.

Claims

1. A polyether ester polyol, which comprises a repeating structure of formula (1) and a blocked alcohol hydroxyl group: ， wherein R1 is at least one of an aromatic ring or an aromatic heterocyclic ring, and the mass content of R1 in formula (1) is 4.5% - 44%; R2 is at least two of saturated alkane groups having 2 - 5 carbon atoms; x is 2 - 20; The mass percentage of the repeating structure of formula (1) in the polyether ester polyol is greater than 75%; The average functionality of the blocked alcohol hydroxyl group is 1.95 - 2.00; The number average molecular weight of the polyether ester polyol is 800 - 5000.

2. A method for preparing a polyether ester polyol, which comprises reacting an aromatic dicarboxylic acid, its esterified product or its anhydride with a polyether diol to obtain the polyether ester polyol according to claim 1.

3. The preparation method according to claim 2, wherein The number average molecular weight of the polyether diol is 100 - 1000.

4. The preparation method according to claim 3, characterized in that, The degree of polymerization of the polyether diol is 2 - 20.

5. The preparation method according to claim 4, wherein, The degree of polymerization of the polyether diol is 3 - 10.

6. The preparation method according to claim 3, characterized in that The polyether diol is a copolymer diol obtained by reacting at least two of tetrahydrofuran, ethylene oxide, propylene oxide, 2 - methyltetrahydrofuran or 3 - methyltetrahydrofuran.

7. The preparation method according to claim 3, wherein The polyether diol is a mixture of at least two of polytetrahydrofuran, polypropylene glycol, and polyethylene glycol.

8. A method for preparing polyurethane elastic fibers, non-woven fabrics, films or elastomers using the polyether ester polyol according to claim 1 or the polyether ester polyol prepared by the method according to any one of claims 2 to 7 as a raw material, characterized in that, The polyurethane elastic fiber, non - woven fabric, film or elastomer is prepared by solution processing or melt processing.

9. A polyurethane elastic fiber, non - woven fabric, film or elastomer prepared by the method according to claim 8.

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