High-resilience coarse denier spandex and method of making same

Abstract

The application provides high-resilience coarse-denier spandex and a preparation method thereof. By introducing a specific aromatic group-polyether block structure into a soft segment of a polymer molecular structure of the spandex, the high-resilience coarse-denier spandex is prepared through dry spinning or melt spinning. Compared with conventional coarse-denier spandex, the high-resilience coarse-denier spandex provided by the application has higher recovery modulus and lower permanent deformation rate, can prolong the service life of elastic fabric or product while meeting the fabric resilience performance, and can save the use amount of spandex while ensuring the product resilience performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of chemical fiber synthesis, in particular to a high-resilience coarse denier spandex and a preparation method thereof. BACKGROUND

[0002] Spandex is the abbreviation of polyurethane fiber, which is the most widely used elastic fiber at present. The polymer of spandex is a block copolymer of soft segment and hard segment. The soft segment is generally composed of flexible chain segment, which is generally obtained by reacting polyether, polyester, hydroxyl-terminated polybutadiene and other polyols with polyisocyanate for connecting the polyols. The hard segment is composed of chain segment with excellent crystallization performance, which is generally obtained by reacting polyisocyanate with small molecule polyol and small molecule amine chain extender. The mainstream spandex on the market is dry-process polyether spandex. The main raw materials of dry-process polyether spandex are polytetramethylene ether glycol, diphenylmethane diisocyanate and chain-extending amine. A polyurethane urea solution is prepared by two-step polymerization reaction, and then necessary additives are added to prepare a polyurethane urea spinning solution. Spandex fibers are prepared by duct spinning.

[0003] In some special applications of clothing, higher resilience performance of spandex is required. For example, the collar, cuff, ankle and other positions of clothing, diapers, medical bandages and elastic belts require better retraction performance of spandex, i.e. the spandex in these positions needs to have greater recovery force after stretching so that the fabric in these positions can be tightly stretched around the wrist, neck, torso or other corresponding body parts. In order to meet the recovery force requirement of the above-mentioned applications, a plurality of spandex filaments are usually twisted into the form of coarse denier spandex to improve the recovery force of spandex.

[0004] In addition to the form of coarse denier spandex, the resilience performance of spandex filaments can also be improved by reducing the molecular weight of polyols and increasing the content of hard segments to improve the recovery modulus of the filaments, thereby improving the recovery force of spandex. However, this method will increase the permanent deformation rate of spandex. In the use scenarios mentioned above, the fabric is often stretched and contracted frequently, and the spandex is prone to permanent deformation after a period of use, such as deformation of the cuff, ankle and elastic belt of trousers, which affects the service life of the clothing. Therefore, the excellent coarse denier spandex should have a high recovery modulus and a strong resistance to plastic deformation. SUMMARY

[0005] The application provides a high-resilience coarse denier spandex, by changing the molecular structure of the soft segment of the spandex monofilament, the recovery modulus of the spandex is improved, the permanent set of the spandex is reduced, and the service life of the spandex is increased. The specific scheme is as follows.

[0006] A high-resilience coarse denier spandex, the denier of the spandex is greater than 70 denier, and the soft segment of the polymer molecular structure of the spandex comprises a repeating unit represented by the following formula (1):

[0007]

[0008] In the formula, R1 is at least one of an aromatic ring and an aromatic heterocycle, and the mass content of R1 in the repeating unit is 4.5% to 44%; R2 is at least one of saturated alkane groups with 2 to 5 carbon atoms; and x is 2 to 20.

[0009] The soft segment accounts for 75% to 95% of the mass of the polymer in the polymer molecule of the spandex, and the mass of the repeating unit represented by the formula (1) accounts for more than 75% of the mass of the soft segment.

[0010] Optionally, the high-resilience coarse denier spandex is composed of three or more spandex monofilaments.

[0011] Optionally, the high-resilience coarse denier spandex is a monofilament.

[0012] Optionally, R2 is at least two of saturated alkane groups with 2 to 5 carbon atoms.

[0013] Optionally, R2 is preferably a saturated alkane group with 2 carbon atoms.

[0014] Optionally, R1 is a benzene ring.

[0015] Optionally, x in the formula (1) is 3 to 10.

[0016] The high-resilience coarse denier spandex can be prepared by dry spinning or melt spinning, and specifically, the preparation method of dry spinning is as follows:

[0017] A preparation method of a high-resilience coarse denier spandex, characterized in that, comprising the following steps,

[0018] Step 1): using diisocyanate raw materials to end-cap a polyether ester polyol comprising an aromatic group-polyether block structure to prepare a prepolymer;

[0019] Step 2): using a polar solvent to dissolve the prepolymer to obtain a prepolymer solution;

[0020] Step 3): using a mixed solution of a chain extender and a terminator to chain-extend the prepolymer to obtain a polyurethane / polyurethane urea solution;

[0021] Step 4) : adding an auxiliary to prepare a spinning dope;

[0022] Step 5) : the prepared spinning dope is dry spun, and the monofilaments are combined by a false twist device before winding to prepare a spandex multifilament.

[0023] The preparation method of melt spinning is as follows:

[0024] A preparation method of high-resilience coarse-denier spandex, comprising the following steps:

[0025] Step a) : adding a diisocyanate raw material, a polyether ester polyol containing an aromatic group-polyether block structure, and a small-molecule polyol chain extender into a reaction container respectively;

[0026] Step b) : mixing the materials in the reaction container, and heating the materials during or after the mixing to react and extrude and granulate to prepare polyurethane granules;

[0027] Step c) : drying the polyurethane granules, melt spinning after adding an auxiliary to obtain coarse-denier spandex with a denier of 70D or more.

[0028] Further, the polyether ester polyol containing an aromatic group-polyether block structure has the following characteristics:

[0029] The polyether ester polyol contains a repeating unit represented by formula (1) and a capped alcohol hydroxyl group:

[0030]

[0031] wherein R1 is at least one of an aromatic ring and an aromatic heterocyclic ring, and the mass content of R1 in the repeating unit is 4.5% to 44%; R2 is at least one of saturated alkyl groups with a carbon atom number of 2-5; x is 2-20, preferably 3-10;

[0032] The mass percentage of the repeating unit represented by formula (1) in the polyether ester polyol is greater than 75%;

[0033] The average functionality of the capped alcohol hydroxyl group is 1.95-2.00;

[0034] The number average molecular weight of the polyether ester polyol is 800-5000, preferably 1000-3500, more preferably 1400-2500, and most preferably 1500-2300.

[0035] Optionally, the viscosity of the polyether ester polyol at 90°C and a shear rate of 1S-1 can be less than 500 poise, preferably less than 200 poise.

[0036] The use of the coarse-denier spandex described above in clothing collars, clothing cuffs, sock tops, diapers, medical bandages, elastic ribbons, and fabrics, clothing, or sanitary material products containing the same.

[0037] Advantages:

[0038] The high-resilience coarse-denier spandex provided by the present application is prepared by using a polyether ester polyol with a specific structure as a soft segment raw material, and the soft segment of the spandex molecular structure comprises an aromatic group-polyether block structure. The high-resilience coarse-denier spandex is spun, and compared with conventional polyether type or polyester type spandex, has better recovery modulus and lower permanent set rate, can meet the requirements of fabric resilience performance, prolong the service life of elastic fabric or product, and save the use amount of spandex while ensuring the resilience performance of the product. DETAILED DESCRIPTION

[0039] In the collar, cuff, cuff, and products such as diapers, medical bandages, and elastic belts that require high elastic recovery force, a plurality of spandex filaments are usually false twisted into coarse-denier spandex to improve the elastic recovery force of the product. These products often need to be stretched and contracted frequently, and thus are more prone to deformation and reduced product shrinkage. Therefore, it is necessary to develop a coarse-denier spandex product that can ensure elastic recovery force and has a lower permanent set rate to prolong the service life of the above-mentioned type of product.

[0040] Specifically, the present application provides a high-resilience coarse-denier spandex, wherein the denier of the coarse-denier spandex is greater than 70 denier, and the soft segment of the polymer molecular structure of the spandex comprises a repeating unit represented by the following formula (1):

[0041]

[0042] wherein R1 is at least one of an aromatic ring and an aromatic heterocycle, and the mass content of R1 in the repeating unit is 4.5% to 44%; R2 is at least one of saturated alkane groups with 2 to 5 carbon atoms; and x is 2 to 20.

[0043] The soft segment in the polymer molecule of the spandex accounts for 75% to 95% of the mass of the polymer, and the mass of the repeating unit represented by formula (1) accounts for more than 75% of the mass of the soft segment.

[0044] The coarse-denier spandex of the present application can be a spandex multifilament false twisted by 3 or more spandex filaments, or a coarse-denier monofilament. The spandex multifilament is usually spun by dry spinning, and the coarse-denier monofilament is usually spun by melt spinning.

[0045] For ease of description, the aromatic ring or aromatic heterocycle represented by R1 is collectively referred to as an aromatic group hereinafter.

[0046] In the repeating unit structure shown in formula (1) above, the polyether structure is arranged in intervals with aromatic groups, and the spandex having the soft segment structure features described above has better plastic deformation resistance. The introduction of rigid aromatic groups also makes the spandex have higher modulus. In the repeating unit, if the content of the aromatic group R1 is too high, the rigidity of the molecules in the finally prepared spandex will be too large, which will affect the elongation at break and the ability to resist plastic deformation of the spandex. If the content of the aromatic group R1 is too low, the spandex will not have the effect of reducing the permanent set, and the recovery modulus of the spandex will be reduced. Therefore, in the present application, the mass content of R1 in the repeating unit is preferably 4.5% to 44%. R1 is at least one of an aromatic ring and an aromatic heterocycle. The aromatic ring can be at least one of a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, and the like. The aromatic heterocycle can be at least one of a pyridine, a furan ring, a thiazole ring, a pyrimidine ring, and the like. In an alternative embodiment, R1 includes 1-4 methylene groups in addition to the aromatic ring or the aromatic heterocycle.

[0047] In the molecular structure of the soft segment, there can also be some modified structures such as aliphatic structures, but in order to solve the technical problems proposed in the present application, the repeating unit of the structure of formula (1) above accounts for more than 75% of the mass of the soft segment, and in a preferred embodiment, the mass percentage of the repeating unit shown in formula (1) in the soft segment is greater than 95%.

[0048] In the structure of formula (1) above, (R2-O) xThe structure actually represents a polyether segment, wherein x represents the polymerization degree of the (R2-O) structure, the polymerization degree x of the polyether segment is preferably 2-20, more preferably 3-10, and the molecular weight of the polyether segment can be 100-1000, preferably 300-1000, more preferably 600-900. In fact, only when the polymerization degree and the number average molecular weight of the polyether segment are in the above range, the structure in which the polyether structure and the aromatic group structure are arranged at intervals can improve the elastic modulus of the spandex while also improving the ability to resist plastic deformation. If the length of the polyether segment in the soft segment is too short, the spandex molecules prepared will be too rigid, affecting the elongation at break of the spandex, and if the length of the polyether segment is too long, it will not be able to reduce the permanent set of the spandex. In the polyether segment, R2 is preferably a saturated alkane group with 2-5 carbon atoms, wherein the smaller the number of carbon atoms in R2, the greater the density of ether oxygen bonds, which will enhance the interaction between the soft segment and the hard segment in the spandex molecule, thereby increasing the tensile modulus and the recovery modulus, but is not conducive to elongation. Accordingly, the larger the number of carbon atoms between the ether oxygen bonds, the smaller the density of the ether oxygen bonds, which will weaken the interaction between the soft segment and the hard segment of the polyurethane, thereby increasing the elongation of the spandex. The polyether segment with 2-3 carbon atoms in the monomer R2 is usually derived from polyethylene glycol and polypropylene glycol, and compared with polytetrahydrofuran with 4 carbon atoms, the polyether segment with 2-3 carbon atoms has a lower cost, so in actual production, the polyether segment formed by copolymerization of monomers with different carbon atom numbers is preferably used to reduce the cost and adjust the performance. Specifically, the polyether segment can be a saturated alkane group with 2, 3 or 4 carbon atoms arranged at intervals through ether oxygen bonds. The polyether segment of the above structure can be a mixture of at least two of polytetrahydrofuran, polypropylene glycol and polyethylene glycol, or a segment of a copolymer diol obtained by reacting at least two of tetrahydrofuran, ethylene oxide, propylene oxide, 2-methyltetrahydrofuran or 3-methyltetrahydrofuran, and the polyether segment is preferably a segment of a copolymer diol obtained by reacting tetrahydrofuran with at least one of ethylene oxide, propylene oxide, 2-methyltetrahydrofuran or 3-methyltetrahydrofuran.

[0049] In the molecular structure of the spandex described in the present application, the soft segment accounts for 80%-97% of the mass of the polymer molecules. If the mass ratio of the soft segment in the polymer is too high, the breaking strength of the spandex will be too low, and the mechanical properties will be poor; if the mass ratio of the soft segment in the polymer is too low, the elongation of the spandex will be insufficient, and the stress will be large.

[0050] The present application also provides a preparation method of the high-rebound coarse-denier spandex described above, characterized in that it comprises the following steps,

[0051] Step 1): end-capping a polyether ester polyol containing an aromatic group-polyether block structure with a diisocyanate raw material to prepare a prepolymer;

[0052] Step 2): dissolving the prepolymer using a polar solvent to obtain a prepolymer solution;

[0053] Step 3): chain extending the prepolymer using a mixed solution of chain extender and terminator to obtain a polyurethane / polyurethane urea solution;

[0054] Step 4): adding an auxiliary to obtain a spinning dope;

[0055] Step 5): using the prepared spinning dope for dry spinning, and making the filaments cling through a false twist device before winding to obtain a spandex multifilament.

[0056] Further, the polyether ester polyol containing the aromatic group-polyether block structure has the following characteristics:

[0057] The polyether ester polyol contains a repeating unit represented by formula (1) and a terminal alcohol hydroxyl group:

[0058]

[0059] wherein R1 is at least one of an aromatic ring and an aromatic heterocyclic ring, and the mass content of R1 in the repeating unit is 4.5% to 44%; R2 is at least one of saturated alkyl groups with a carbon atom number of 2-5; x is 2-20, preferably 3-10;

[0060] The mass percentage of the repeating unit represented by formula (1) in the polyether ester polyol is greater than 75%;

[0061] The average functionality of the terminal alcohol hydroxyl group is 1.95-2.00;

[0062] The number average molecular weight of the polyether ester polyol is 800-5000, preferably 1000-3500, more preferably 1400-2500, and most preferably 1500-2300.

[0063] In the above method, the polyether ester polyol containing the aromatic group-polyether block structure described in step 1) is used as the soft segment raw material of spandex, and the structure represented by formula (1) can be introduced into the molecular structure of spandex.

[0064] The number average molecular weight of the polyether ester polyol described above should be 800-5000, preferably 1000-3500, more preferably 1400-2500, and most preferably 1500-2300. The greater the number average molecular weight of the polyether ester polyol, the greater its viscosity, making it difficult to perform continuous operation on an industrial scale. However, if the molecular weight of the polyether ester polyol is too small, more diisocyanate is required to synthesize the polyurethane prepolymer, resulting in a higher content of urethane groups in the prepolymer, thus increasing the interaction between the molecules of the prepolymer and increasing the viscosity, and the length of the soft segment in the polyurethane formed is shorter, which affects the recovery performance of the final polyurethane fiber.

[0065] The average functionality of the terminal alcohol hydroxyl groups in the polyether ester polyol described above can be 1.95-2.00, preferably 1.96-2.00, and more preferably 1.98-2.00, which ensures that the polyether ester polyol can be smoothly end-capped with isocyanate and then chain-extended with a small molecule amine or alcohol. "Average functionality" refers to the average number of moles of alcohol hydroxyl groups per mole of polyether ester polyol that can participate in a reaction. In the present application, the average functionality of the alcohol hydroxyl groups is calculated using the following formula, taking into account the formation of double bonds from the dehydration of the terminal hydroxyl groups of the polyether diol and the presence of unreacted carboxyl groups:

[0066] Functionality = 2 * moles of alcohol hydroxyl groups / (moles of alcohol hydroxyl groups + moles of carboxyl groups + moles of double bonds)

[0067] The polyether ester polyol can be obtained by condensation reaction or transesterification reaction of an aromatic diacid, an ester thereof, or an acid anhydride thereof with a polyether diol. The aromatic diacid can be selected from one or more of terephthalic acid, isophthalic acid, phthalic acid, diphenic acid, 1,4-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, 2,5-furan dicarboxylic acid, p-xylylene dicarboxylic acid, m-xylylene dicarboxylic acid, o-xylylene dicarboxylic acid. The polyether diol can be polyethylene glycol, polypropylene glycol, polytrimethylene ether glycol, polytetrahydrofuran ether glycol, or a copolymer diol obtained by reacting tetrahydrofuran with a monomer such as ethylene oxide, propylene oxide, 2-methyltetrahydrofuran, or 3-methyltetrahydrofuran, preferably a mixture of at least two of polytetrahydrofuran, 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, more 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.

[0068] The high-resilience coarse denier spandex prepared by the method of the present application, the diisocyanate raw material in step 1) can be one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate and its isomers.

[0069] The polar solvent in step 2) is at least one of N,N-dimethylformamide or N,N-dimethylacetamide.

[0070] The chain extender in step 3) can use amine or alcohol chain extender, wherein the amine chain extender can be a binary amine with carbon atom number of 2-30, for example, can be selected from one or more of ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, methylpentylenediamine, methylpropylenediamine, hexylenediamine, triethylenediamine, xylylenediamine, phenylenediamine, diaminocyclohexane, hexamethylenediamine, dopamine; the alcohol chain extender can be one or more of ethylene glycol, 1,4-butanediol, diethylene glycol, 1,6-hexanediol, 1,3-propanediol, 1,4-dihydroxymethylcyclohexane and other common chain extenders. The chain terminator can be a monamine with carbon atom number of 2-20, which can be selected from one or more of ethylamine, isopropylamine, n-butylamine, t-butylamine, hexylamine, dimethylamine, diethylamine, dipropylamine, di-n-butylamine, di-t-butylamine, diisobutylamine, diisopropylamine, cyclohexylamine or ethanolamine.

[0071] The air speed of dry spinning in step 5) is 10-20 Nm 3 / min, and the gas temperature is above 240℃. The fineness of the monofilament is 10-20 denier.

[0072] The false twist device is at least one of friction disc type false twister, air flow false twister, rubber ring false twister and rotor false twister.

[0073] To meet the use requirements of high-resilience spandex, the denier of the coarse denier spandex should be above 70 denier, and the coarse denier spandex multifilament prepared by the above dry spinning is twisted by at least 3 monofilaments.

[0074] Alternatively, the above high-resilience coarse denier spandex is prepared by melt spinning, and the specific method is as follows:

[0075] A method for preparing high-resilience coarse denier spandex, comprising the following steps:

[0076] Step a) adding diisocyanate raw material, polyether ester polyol containing aromatic group-polyether block structure and small molecule polyol chain extender into the reaction container respectively;

[0077] Step b) mixing the materials in the reaction container, and heating the materials during or after mixing to react and extruding and granulating to prepare polyurethane particles;

[0078] Step c) drying the polyurethane particles, melt spinning after adding the auxiliary, to obtain a coarse denier spandex with a denier of 70D or more.

[0079] The raw materials for melt spinning spandex such as diisocyanate, polyether ester polyol, etc. are similar to those for dry spinning, with the difference being that the chain extender in step a) is only an alcohol chain extender.

[0080] The present application also provides the use of the high-rebound coarse denier spandex described above in clothing collars, clothing cuffs, sock tops, diapers, medical bandages, elastic ribbons, and fabrics, clothing or sanitary products containing the same.

[0081] Examples

[0082] The present application is described in more detail below by way of examples, in which the test methods for the parameters involved are as follows:

[0083] 1. Average functionality:

[0084] Functionality = 2 * alcohol hydroxyl molar number / (alcohol hydroxyl molar number + carboxyl molar number + double bond molar number).

[0085] 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, and 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 number of the corresponding end group in the polyether ester diol.

[0086] 2. Tensile 300% stress, breaking strength, and elongation at break: all according to the “Textile Industry Standard of the People’s Republic of China” FZ / T 50006-2013, “Spandex Filament Tensile Property Test Method”.

[0087] 3. Plastic deformation test:

[0088] The prepared sample is clamped into the upper clamp holder at one end, and a pre-tension is applied to the other end to straighten the sample along the axial direction and clamp it into the lower clamp holder, and the instrument is started.

[0089] The sample is stretched from 0% elongation L0 to 300% elongation L1 at a speed of 500 mm / min, and then returned to 0% elongation, with four cycles of stretching and recovery; during the fifth stretching to 300% elongation, the force value F1 at 200% elongation is recorded, with a delay of 30 s, and then returned to 0% elongation, during which the force value F2 at 200% recovery is recorded; with a delay of 30 s, the sixth stretching is performed, and the length L2 of the sample at the pre-tension is recorded.

[0090] Plastic deformation rate calculation formula: (L2-L0) / L0*100%

[0091] Wherein "5LP200%" represents the stress value when the fifth stretching to 200% elongation, that is, F1, "5UP200%" represents the rebound stress value when the fifth recovery to 200% elongation, that is, F2, which can be used to characterize the recovery modulus; "plastic deformation rate" represents the increase ratio of the length of spandex filament compared with the original length after 5 times of stretching; "5UP200% / 5LP200%" represents the ratio of the recovery stress when the fifth recovery to 200% elongation and the tensile stress when stretching to 200% elongation in the 5 times of stretching cycle test.

[0092] 4. Elasticity test of fabric containing coarse denier spandex

[0093] The coarse denier spandex filament of the present application can be knitted into fabric in the form of bare yarn or wrapped yarn. It includes the toe, waist opening knitted by hosiery machine; mesh, lace knitted by warp knitting machine; yoga, trousers fabric knitted by circular machine, etc.; and wrapped yarn for knitting of woven fabric; braid; diaper, etc. The excellent elasticity of the fabric can improve the comfort of the wearer, reduce fatigue and energy loss caused by muscle vibration during exercise.

[0094] The test method for judging the tensile and rebound characteristics NH of the fabric is three times of stretching cycle constant elongation method, the constant elongation rate is 65%, and the tensile test speed is 200mm / min. The tensile force values 1LP30, 1LP40, 1LP50 when the first stretching to 30%, 40%, 50% elongation, and the recovery force values 3UP30, 3UP40, 3UP50 when the third recovery to 30%, 40%, 50% are recorded respectively, and the tensile and rebound characteristics NH are calculated.

[0095]

[0096] NH is a characterization way for the recovery strength of high rebound fabric. The higher the NH value, the more sufficient recovery force the fabric maintains after multiple stretching cycles, which ensures that the garment is close-fitting and not bulging when worn by the human body, and improves the accuracy of action positioning of the limbs during exercise.

[0097] The test method for judging the permanent deformation rate SET of the fabric is three times of stretching cycle constant elongation method, the constant elongation rate is 75%, and the tensile test speed is 200mm / min. The elongation length L1 when the third stretching recovery to the force value of 0 is recorded, and the permanent deformation rate SET is calculated.

[0098]

[0099] Wherein, L0 is the original length of the sample test mm;

[0100] L1 is the length of the fabric after the third stretch recovery to 0 force value, and the length is recorded in mm;

[0101] SET is the deformation accumulation of the fabric after multiple stretching, and a lower SET value is beneficial to the shape retention of the fabric.

[0102] In addition, the antioxidants mentioned in the following examples are antioxidant 245, the dyeing assistants are DH300R or 2462B, and the light stabilizers are Tinuvin 791, which are all commercially available substances.

[0103] Example 1:

[0104] A high-rebound coarse-denier spandex is prepared by using a polyether ester polyol with a molecular weight of 1500 as a raw material, wherein the polyether ester polyol is prepared from 17 parts by weight of polyethylene glycol PEG600 (with a number average molecular weight of 600) and 2.7 parts by weight of terephthalic acid, has a number average molecular weight of 1500, an average functionality of 1.98, and a viscosity of 25 poise at 90°C and is a liquid at room temperature. -1

[0105] 100 kg of the above polyether ester polyol is added to a reaction kettle that has been heated to 45°C, and stirring is started at a speed of 150 rpm. Then, 26.5 kg of diphenylmethane diisocyanate is added, and the temperature is raised to 90°C after 5 minutes of stirring. The pre-polymer is obtained by reacting at 90°C for 2 hours.

[0106] The pre-polymer is cooled to 50°C, and 161 kg of dimethylacetamide (DMAc) is used to dissolve the pre-polymer. Then, an amine solution containing 2.33 kg of ethylenediamine (EDA) and 0.28 kg of diethylamine (DEA) with a mass concentration of 3.2% is added, and the stirring speed is increased to 300 rpm for chain extension. After the chain extension is completed, necessary antioxidants, dyeing assistants and other auxiliaries are added, and the solution is aged for 30 hours to obtain a spinning dope with a solid content of 35%. The above dope is subjected to dry spinning, and an air flow false twister is used to make the monofilaments cling to each other, thereby obtaining high-rebound coarse-denier spandex PUU-1 with a monofilament fineness of 15 denier and a total denier of 120D.

[0107] Example 2:

[0108] A high-rebound coarse-denier spandex is prepared by using a polyether ester polyol with a molecular weight of 2120 as a raw material, wherein the polyether ester polyol is prepared from 17 parts by weight of polyethylene glycol PEG600 (with a number average molecular weight of 600) and 3.2 parts by weight of terephthalic acid, has a number average molecular weight of 2120, an average functionality of 1.98, and a viscosity of 25 poise at 90°C and is a liquid at room temperature. -1

[0109] ​​Put 100 kg of the above polyether ester polyol into a reactor which has been thermostated to 45°C. Start stirring at 150 rpm. Add 21.3 kg of diphenylmethane diisocyanate. After stirring for 5 min, raise the temperature to 90°C. React at 90°C for 2 h to obtain a prepolymer.

[0110] Cool the prepolymer to 50°C. Dissolve the prepolymer in 154.4 kg of dimethylacetamide (DMAc). Then add an amine solution containing 2.25 kg of ethylenediamine (EDA) and 0.28 kg of diethylamine (DEA) with a mass concentration of 3%. Increase the stirring speed to 300 rpm to carry out chain extension. After the chain extension is complete, add necessary antioxidants, dyeing aids, and other auxiliaries, and then age for 30 h to obtain a spinning dope with a solid content of 35%. Dry-spin the above dope, and use an air flow false twister to make the filaments cling together to obtain high-resilience coarse denier spandex PUU-2 with a filament fineness of 15 denier and a total denier of 120 D.

[0111] Example 3:

[0112] Use a polyether ester polyol with a molecular weight of 1800 as a raw material to prepare high-resilience coarse denier spandex, wherein the polyether ester polyol is prepared from 8.5 parts by weight of polytetrahydrofuran PTG650 (number average molecular weight 650), 8.5 parts by weight of polyethylene glycol PEG600 (number average molecular weight 600), and 3.52 parts by weight of terephthalic acid, has a number average molecular weight of 1800, an average functionality of 1.98, and a viscosity of 45 poise at 90°C 1S -1

[0113] Put 100 kg of the above polyether ester polyol into a reactor which has been thermostated to 45°C. Start stirring at 150 rpm. Add 23.5 kg of diphenylmethane diisocyanate. After stirring for 5 min, raise the temperature to 90°C. React at 90°C for 2 h to obtain a prepolymer.

[0114] Cool the prepolymer to 50°C. Dissolve the prepolymer in 157 kg of dimethylacetamide (DMAc). Then add an amine solution containing 2.27 kg of ethylenediamine (EDA) and 0.28 kg of diethylamine (DEA) with a mass concentration of 3.2%. Increase the stirring speed to 300 rpm to carry out chain extension. After the chain extension is complete, add necessary antioxidants, dyeing aids, and other auxiliaries, and then age for 30 h to obtain a spinning dope with a solid content of 35%. Dry-spin the above dope, and use an air flow false twister to make the filaments cling together to obtain high-resilience coarse denier spandex PUU-3 with a filament fineness of 15 denier and a total denier of 120 D.

[0115] Example 4:

[0116] ​The polyether ester polyol with a molecular weight of 1500 used in Example 1, 1,4-butanediol and diphenyl methane diisocyanate were metered into a twin-screw extruder in a molar ratio of 1:2:3, respectively, and extruded continuously at 195°C for a polymeric reaction, pelletized underwater, and dried to a moisture content of the polyurethane particles of less than 100 ppm. After adding necessary antioxidants, light stabilizers and other auxiliaries, the mixture was uniformly mixed and then melt-spun. The melt was pressurized via a single-screw extruder, extruded from a spinneret via a metering pump, and the melt stream was quenched into a cold water tank. After being drawn in hot water and drawn on a hot roller, a melt-spun high-rebound coarse denier spandex TPU-1 with a fineness of 120D was obtained by winding.

[0117] Comparative Example 1:

[0118] 100 kg of polytetrahydrofuran PTMG2000 (number average molecular weight of 2000) was added to a reaction kettle that had been heated to 45°C, and stirring was started at a speed of 150 rpm. 22.2 kg of diphenyl methane diisocyanate was added, and after stirring for 5 min, the temperature was raised to 90°C, and the pre-polymer was reacted at 90°C for 2 h.

[0119] The pre-polymer was cooled to 50°C, and 155.5 kg of dimethylacetamide (DMAc) was used to dissolve the pre-polymer. Then, an amine solution containing 2.26 kg of ethylenediamine (EDA) and 0.28 kg of diethylamine (DEA) was added at a concentration of 3.2%. The stirring speed was increased to 300 rpm, and chain extension was performed. After the chain extension was completed, necessary antioxidants, dyeing auxiliaries and other auxiliaries were added, and the dope was aged for 30 h to obtain a spinning dope with a solid content of 35%. The above dope was dry-spun, and an air flow false twister was used to make the filaments cling to each other, thereby obtaining a high-rebound coarse denier spandex PUU-0 with a filament fineness of 15 denier and a total denier of 120D.

[0120] Comparative Example 2:

[0121] Polytetrahydrofuran PTMG2000 (number average molecular weight of 2000), 1,4-butanediol and diphenyl methane diisocyanate were metered into a twin-screw extruder in a molar ratio of 1:2:3, respectively, and extruded continuously at 190°C for a polymeric reaction, pelletized underwater, and dried to a moisture content of the polyurethane particles of less than 100 ppm. After adding necessary antioxidants, light stabilizers and other auxiliaries, the mixture was uniformly mixed and then melt-spun. The melt was pressurized via a single-screw extruder, extruded from a spinneret via a metering pump, and the melt stream was quenched into a cold water tank. After being drawn in hot water and drawn on a hot roller, a melt-spun coarse denier spandex TPU-0 with a fineness of 120D was obtained by winding.

[0122] According to the above test method, the following parameters of the coarse denier spandex obtained in Examples 1-4 and Comparative Examples 1-2 were tested, and the test results are summarized in the table below.

[0123]

[0124] From the first four groups of data in the above table, it can be seen that the coarse denier spandex obtained by the dry spinning method of the application has similar tensile stress, breaking strength, breaking elongation and other mechanical properties to the conventional method of polyether type spandex PUU-0, and has more excellent 5UP200% resilience stress value and NH value, that is, better recovery modulus; has lower plastic deformation rate, that is, is not easy to deform, lower SET value can prolong the service life of the fabric, and meets the use requirements of coarse denier spandex.

[0125] From the last two groups of data in the above table, it can be seen that the coarse denier spandex obtained by the melt spinning method of the application has similar tensile stress, breaking strength, breaking elongation and other mechanical properties to the conventional method of melt spinning spandex TPU-0, and has more excellent 5UP200% resilience stress value and NH value, that is, better recovery modulus; has lower plastic deformation rate, that is, is not easy to deform, lower SET value can prolong the service life of the fabric, and meets the use requirements of coarse denier spandex.

[0126] In summary, the coarse denier spandex provided by the application has better recovery modulus and lower permanent deformation rate compared with conventional coarse denier spandex, which can improve the resilience of the fabric while prolonging the service life of the elastic fabric or product.

Claims

1. A high-rebound coarse denier spandex characterized in that, The coarse denier spandex has a denier greater than 70 denier, and the soft segment of the polymer molecular structure of the spandex comprises a repeating unit represented by the following formula (1): Formula (1), wherein R1 is at least one of an aromatic ring and an aromatic heterocycle, and the mass content of R1 in the repeating unit 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; the (R2-O)x group x molecular weight of the structure is 300 to 1000; The soft segment in the polymer molecule of the spandex accounts for 75%-90% of the polymer mass, and the mass of the repeating unit represented by formula (1) accounts for more than 75% of the mass of the soft segment.

2. The high-resilience coarse denier spandex of claim 1, wherein, The high-resilience coarse denier spandex is made of 3 or more spandex filaments.

3. The high-resilience, coarse-denier spandex of claim 1, wherein, The high-resilience coarse denier spandex is a single filament.

4. The high-resilience, coarse-denier spandex of claim 1, wherein, The R2 is at least two of saturated alkane groups with carbon atom number of 2-5.

5. The high-resilience coarse denier spandex of claim 1, wherein, The R2 is a saturated alkane group with carbon atom number of 2.

6. The high-resilience coarse denier spandex of claim 1, wherein, The R1 is a benzene ring.

7. A process for the production of high resilience coarse denier spandex characterized by, The method comprises the following steps: Step 1): using diisocyanate raw materials to end-cap polyether ester polyols containing aromatic group-polyether block structure to prepare a prepolymer; Step 2): using a polar solvent to dissolve the prepolymer to obtain a prepolymer solution; Step 3): using a mixed solution of a chain extender and a terminator to chain-extend the prepolymer to obtain a polyurethane / polyurethane urea solution; Step 4): adding an auxiliary to prepare a spinning dope; Step 5): using dry spinning to spin the prepared spinning dope, and making the single filaments cling through a false twisting device before winding to obtain the coarse denier spandex; The polyether ester polyol comprises a repeating unit represented by formula (1) and an end-capped alcohol hydroxyl group: Equation (1), wherein R1 is at least one of an aromatic ring and an aromatic heterocycle, and the mass content of R1 in the repeating unit is 4.5% to 44%; R2 is at least one of saturated alkyl groups having 2 to 5 carbon atoms, and x is 2 to 20; the (R2-O)x group x molecular weight of the structure is 300 to 1000; The mass percentage of the repeating unit represented by formula (1) in the polyether ester polyol is greater than 75%; The average functionality of the end-capped alcohol hydroxyl group is 1.95-2.00; The number average molecular weight of the polyether ester polyol is 800-5000.

8. The method for preparing high-resilience coarse denier spandex according to claim 7, characterized in that, The false twisting device is at least one of a friction disc type false twister, an air flow false twister, a rubber ring false twister, and a rotor false twister.

9. A method for preparing high-resilience coarse denier spandex, comprising the following steps: Step a) adding diisocyanate raw materials, polyether ester polyols containing aromatic group-polyether block structure, and small molecule polyol chain extenders into reaction containers respectively; Step b) mixing the materials in the reaction containers, and heating the materials during or after mixing to react and extrude and granulate to obtain polyurethane particles; Step c) drying the polyurethane particles, adding an auxiliary, and then melt spinning to obtain coarse denier spandex with a denier of 70D or more; wherein The polyether ester polyol comprises a repeating unit represented by formula (1) and an end-capped alcohol hydroxyl group: Formula (1), wherein R1 is at least one of an aromatic ring and an aromatic heterocycle, and the mass content of R1 in the repeating unit 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; the (R2-O)x group x molecular weight of the structure is 300 to 1000; The mass percentage of the repeating unit represented by formula (1) in the polyether ester polyol is greater than 75%; The average functionality of the end-capped alcohol hydroxyl group is 1.95-2.00; The number average molecular weight of the polyether ester polyol is 800-5000.

10. Use of the coarse denier spandex prepared by the method according to any one of claims 1-6 or 7-9 in clothing collars, clothing cuffs, sock tops, diapers, medical bandages, elastic belts, and fabrics, clothing, or sanitary material products containing the same.

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