Modified polyester, preparation method thereof and production method of polyester fiber

Abstract

The invention relates to the field of functional polyester fiber materials, and discloses modified polyester, a preparation method thereof and a production method of polyester fiber. The modified polyester contains a structural unit A as shown in a formula (I), a structural unit B as shown in a formula (II) and a structural unit C as shown in a formula (III). The preparation method of the modified polyester comprises the following steps: in the presence of a catalyst, mixing a binary acid monomer, a dihydric alcohol monomer, a component a, a component b and a component c for polymerization, the component a is a compound with a structure as shown in a formula (I), the component b is a compound with a structure as shown in a formula (II), and the component c is a compound with a structure as shown in a formula (III). The modified polyester provided by the invention has stable mechanical properties and relatively high softness and crease resistance, the appearance and hand feeling of the polyester fiber can be improved, and the requirements in the fields of clothing, home furnishing and the like are met.

Description

Technical Field

[0001] The present invention relates to the field of functional polyester fiber materials, and in particular, to a modified polyester, a preparation method thereof, and a production method of polyester fibers. Background Art

[0002] Polyester has the advantages of high strength, high modulus, wear resistance, dimensional stability, stable chemical properties, etc., and is widely used in various fields such as clothing, decoration, and industry. With the continuous improvement of people's living standards, polyester fiber textiles are difficult to meet people's needs in terms of wearing performance. People's requirements for fiber textiles no longer stay at the simple requirement of comfort in the past. Functional textiles such as soft handfeel, wrinkle resistance, and comfortable wearing are increasingly attracting people's attention. Designing and developing polyester fiber textiles with both softness and wrinkle resistance functions has significant significance and value for innovating product concepts and increasing product added value, especially in the fields of business clothing, military clothing, and high-end home textiles, etc., having broad commercial prospects.

[0003] Currently, there are many studies on physically or chemically modifying polyester fibers to improve the softness of polyester. For example, CN102965761A discloses a one-step hydrophilic polyester / high-shrinkage polyester blended yarn and its preparation method. The blended yarn is made by spinning hydrophilic copolyester chips and high-shrinkage copolyester chips in a one-step process. The hydrophilic copolyester chips are composed of purified terephthalic acid, ethylene glycol, sodium isophthalate diol-5-sulfonate, polyethylene glycol, and other diols, wherein polyethylene glycol serves as a flexible segment. The resulting blended yarn has improved softness, hydrophilicity, and dyeability. CN104231248A copolymerizes purified terephthalic acid, 1,4-butanediol, and polyether polyol to produce polyester chips. The polyester chips are then melt-spinned, drawn, and false-twisted to produce elastic fibers. The resulting textiles have good natural resilience, high elasticity, bright dyeing, and softness. CN108998850A discloses a production process for hydrophilic elastic cotton-like polyester fiber and fabric. The fiber is made by direct spinning after copolymerization of purified terephthalic acid, ethylene glycol, isophthalic acid and neopentyl glycol. The resulting high-shrinkage polyester fiber has a soft and elastic feel and good anti-hair and anti-pilling properties. CN114016143A discloses a production process for hydrophilic elastic cotton-like polyester fibers and fabrics, including the preparation of modified polyester masterbatch and a melt spinning process. During the polymerization stage of terephthalic acid and ethylene glycol, sodium 3,5-isophthalate sulfide is added to improve dyeing properties, and polyethylene glycol is added to improve moisture absorption properties. The macromolecular chain of polyethylene glycol contains hydrophilic groups, which increase the amorphous region of the copolyester product and enhance its hydrophilicity. The composite polyester fibers are treated with a dilute alkaline solution to change their regularity and reduce some intermolecular forces, resulting in uneven shapes such as micropores in the fibers that can store air, thereby increasing the warmth retention of the cotton-like polyester fibers and imparting a soft feel.

[0004] In summary, most of these existing methods use dibasic acids such as isophthalic acid, sodium isophthalate diol 5-sulfonate, and diols such as polyethylene glycol to be added to the polymerization system of conventional polyester, which destroys the regularity of the polyester macromolecular chain. Compared with ordinary polyester fabrics, although the softness and feel of such modified polyester fiber fabrics are greatly improved, the regularity of the polymer macromolecular chain is reduced due to the increase in amorphous regions, and the interaction force between the molecular chains is reduced, resulting in poor anti-wrinkle performance. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problems of low regularity and poor anti-wrinkle performance of polyester molecular chains in the prior art, and to provide a modified polyester with high softness and anti-wrinkle performance while ensuring stable mechanical properties, a preparation method thereof, and a preparation method of polyester fiber. The modified polyester has stable performance and is not easy to fail, effectively improving the appearance and feel of the polyester fiber.

[0006] To achieve the above object, a first aspect of the present invention provides a modified polyester, which contains a structural unit A represented by formula (I), a structural unit B represented by formula (II), and a structural unit C represented by formula (III);

[0007]

[0008]

[0009] wherein, R1, R2, R3, R4, R5, R6 are each independently a C1-C10 alkyl group, and m, n, p are each independently a positive integer from 1 to 10; R I , R II , R III , R a , R b , R c , R d are each independently hydrogen or a C1-C10 alkyl group; M is sodium or potassium; X is fluorine, chlorine, bromine or iodine.

[0010] A second aspect of the present invention provides a method for preparing the modified polyester, which method comprises the following steps: under the presence of a catalyst, mixing a dibasic acid monomer, a diol monomer, component a, component b and component c for polymerization;

[0011] Component a is a compound having the structure shown in formula (I), component b is a compound having the structure shown in formula (II), and component c is a compound having the structure shown in formula (III),

[0012]

[0013]

[0014] wherein, R1, R2, R3, R4, R5, R6 are each independently a C1-C10 alkyl group, and m, n, p are each independently a positive integer from 1 to 10; R I , R II , R III , R a , R b , R c , R d are each independently hydrogen or a C1-C10 alkyl group; M is sodium or potassium; X is fluorine, chlorine, bromine or iodine.

[0015] A third aspect of the present invention provides the use of the above-mentioned modified polyester and / or the modified polyester prepared by the above-mentioned method in the preparation of polyester fibers.

[0016] The fourth aspect of the present invention provides a method for preparing polyester fiber, which includes: subjecting the above-mentioned modified polyester and / or the modified polyester prepared by the above method to pre-crystallization and drying, followed by melt spinning to obtain a nascent raw filament, and then bundling, stretching and winding the nascent raw filament.

[0017] Through the above technical solution, the macromolecular chain of the modified polyester provided by the present invention has high regularity and strong intermolecular forces, so that the modified polyester not only has high mechanical properties, but also has high softness and wrinkle resistance, and its performance is stable and not easily fails. It can not only ensure strength but also improve the appearance and feel of polyester fiber, meeting the requirements in the fields of clothing, home furnishing, etc., and providing new ideas for the development of new functional polyester materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the mechanism of ionic bond action during the processing and use of the modified polyester provided by the present invention;

[0019] Figure 2 It is a TGA curve diagram of the modified polyester and conventional polyester prepared in Examples 1 - 3;

[0020] Figure 3 It is a DSC curve diagram of the modified polyester and conventional polyester prepared in Examples 1 - 2;

[0021] Figure 4 It is a nuclear magnetic resonance hydrogen spectrum diagram of the modified polyester prepared in Example 1;

[0022] Figure 5 It is a nuclear magnetic resonance hydrogen spectrum diagram of the modified polyester prepared in Example 2;

[0023] Figure 6 It is a nuclear magnetic resonance hydrogen spectrum diagram of the modified polyester prepared in Example 3. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0025] The first aspect of the present invention provides a modified polyester, which contains structural unit A represented by formula (I), structural unit B represented by formula (II) and structural unit C represented by formula (III);

[0026]

[0027] Among them, R1, R2, R3, R4, R5, and R6 are each independently a C1-C10 alkyl group, which can be a straight-chain alkyl group or a branched-chain alkyl group, preferably a C1-C4 alkyl group, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, etc.; m, n, and p are each independently a positive integer selected from 1-10. In a preferred case, p and n are the same positive integer; R I 、R II 、R III 、R a 、R b 、R c 、R d are each independently hydrogen or a C1-C10 alkyl group, which can be a straight-chain alkyl group or a branched-chain alkyl group, preferably hydrogen or a C1-C4 alkyl group, such as hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, etc.; M is sodium or potassium; X is selected from fluorine, chlorine, bromine, or iodine, preferably iodine.

[0028] Starting from the structure of the polymer chain, the modified polyester provided by the present invention simultaneously incorporates polyether siloxane monomers and cationic and anionic monomers into the macromolecular chain of the polyester. The flexible long-chain structure of the polyether siloxane is used to improve the softness of the polyester material. The additionally introduced cationic and anionic compounds are paired to form ionic bonds to constitute a crosslinked network, and the dynamic reversible crosslinking between polymer chains is achieved by the ionic bond force, increasing the intermolecular force between the molecular chains in the amorphous region of the polyester. After bending, the additionally introduced ion pairs in the modified polyester still tend to find the originally paired ions, and no new ionic bonds are formed at the bending position, thereby improving the wrinkle resistance of the polyester material; during processing, the ionic bonds in the modified polyester can be dissociated and opened in the molten state, without affecting the spinning process of the polyester fiber; the schematic diagram of the mechanism of the ionic bond action during the processing and use of the modified polyester can be as shown in Figure 1 shown.

[0029] The modified polyester provided by the present invention can improve the appearance, feel, etc. of polyester fiber material products, prepare polyester materials with excellent properties to meet the needs of fields such as clothing and home, provide new ideas for the development of new functional polyester materials and high-value-added polyester materials, increase the diversity of polyester materials, and expand the functionality of polyester materials.

[0030] According to the present invention, in order to obtain a modified polyester with better softness and wrinkle resistance, preferably, the content of the structural unit A in the modified polyester is 1-8 wt%, the content of the structural unit B is 0.1-2.5 wt%, and the content of the structural unit C is 0.1-2.5 wt%.

[0031] Further preferably, in the modified polyester, the content of the structural unit A is 1.5-7 wt%, the content of the structural unit B is 0.3-1 wt%, and the content of the structural unit C is 0.3-1 wt%.

[0032] According to the present invention, preferably, the modified polyester further contains a structural unit D represented by the formula (IV) and a structural unit E represented by the formula (V);

[0033]

[0034] Ar is a group having a benzene ring, a naphthalene ring or an anthracene ring, preferably a group having a benzene ring; R' is a C2-C10 alkylene group or a C3-C10 cycloalkylene group, and may be, for example, an ethylene group, a propylene group, a butylene group, a cyclopropylene group, a cyclobutylene group, etc.

[0035] According to the present invention, in order to obtain a modified polyester with more excellent softness and wrinkle resistance, preferably, the content of the structural unit D in the modified polyester is 68.5-81 wt%; the content of the structural unit E is 16-25 wt%.

[0036] According to the present invention, in order to obtain a modified polyester with more excellent softness and wrinkle resistance, preferably, R1, R2, R3, R4, R5 and R6 are the same substituents, more preferably C1-C4 alkyl groups, and further preferably methyl or ethyl groups; R I , R II , R III are the same substituents, more preferably hydrogen or C1-C4 alkyl groups, and further preferably hydrogen or methyl groups; R a , R c , R d are the same substituents, more preferably hydrogen or C1-C4 alkyl groups, and further preferably hydrogen or methyl groups; R b is a C1-C4 alkyl group, more preferably methyl or ethyl group.

[0037] In the present invention, the content of each structural unit in the polyester can be determined by 1 cooperating H-NMR with elemental content detection; among them, the content of the structural unit A can be obtained by first detecting the content of silicon element in the polyester and then converting it through the molecular weight of the structural unit A; the content of the structural unit B can be obtained by first detecting the content of sulfur element in the polyester and then converting it through the molecular weight of the structural unit B; the content of the structural unit C can be obtained by first detecting the content of nitrogen element in the polyester and then converting it through the molecular weight of the structural unit C;

[0038] 1 The specific measuring device and conditions of H-NMR are as follows:

[0039] Nuclear magnetic resonance device model: Bruker 400 MHz nuclear magnetic resonance spectrometer; deuterated solvent: deuterated chloroform, trifluoroacetic acid;

[0040] 1 In the 1H-NMR spectrum, the signals near 2.9 ppm and 8.2 ppm are attributed to methylene and aryl hydrogens respectively. The contents of methylene and aryl hydrogens are obtained from their integral values, and in combination with the contents of methylene and aryl hydrogens in structural unit A, structural unit B, and structural unit C, the contents of structural unit D and structural unit E in the polyester are calculated.

[0041] The second aspect of the present invention provides a method for preparing a modified polyester, which method comprises the following steps: under the presence of a catalyst, mixing a dibasic acid monomer, a diol monomer, component a, component b, and component c for polymerization;

[0042] Component a is a compound having the structure shown in formula (I), component b is a compound having the structure shown in formula (II), and component c is a compound having the structure shown in formula (III),

[0043]

[0044] wherein, R1, R2, R3, R4, R5, and R6 are each independently a C1-C10 alkyl group, and m, n, and p are each independently a positive integer from 1 to 10; R I 、R II 、R III 、R a 、R b 、R c 、R d are each independently hydrogen or a C1-C10 alkyl group; M is sodium or potassium; X is fluorine, chlorine, bromine, or iodine.

[0045] Exemplarily, the structural formula of component a is as shown in formula (VI), component b is one or more of the compound shown in formula (VII), the anhydride of this compound, or the ester of this compound, and component c is one or more of the compound shown in formula (VIII), the anhydride of this compound, or the ester of this compound,

[0046]

[0047] According to the present invention, preferably, R1, R2, R3, R4, R5, and R6 are the same substituents, preferably C1-C4 alkyl groups, more preferably methyl or ethyl; R I 、R II 、R III are the same substituents, preferably hydrogen or C1-C4 alkyl groups, more preferably hydrogen or methyl; R a 、Rc , R d is the same substituent, preferably hydrogen or a C1-C4 alkyl group, more preferably hydrogen or methyl; R b is a C1-C4 alkyl group, more preferably methyl or ethyl. Specifically, R I , R II , R III is hydrogen. In this case, the component b can be isophthalic acid-5-sulfonate, or the anhydride of the isophthalic acid-5-sulfonate or the ester of the isophthalic acid-5-sulfonate, preferably isophthalic acid glycol ester-5-sulfonate.

[0048] According to the present invention, in order to obtain a modified polyester with more excellent flexibility and mechanical properties, preferably, the dibasic acid monomer is one or more of the dibasic acids having the structure shown in formula (IV), the anhydride of the dibasic acid, and the ester of the dibasic acid,

[0049] Ar is a group having a benzene ring, a naphthalene ring or an anthracene ring. The dibasic acid monomer is preferably an aromatic dibasic acid having 8 to C 20 , the anhydride of the aromatic dibasic acid having 8 to C 20 , and the ester of the aromatic dibasic acid having 8 to C 20 , more preferably an ester of an aromatic dibasic acid having 8 to C 20 . Exemplarily, the dibasic acid monomer is one or more of diisophthalate, diterephthalate, phthalate, 2,6-naphthalenedicarboxylate, 1,5-naphthalenedicarboxylate, 2,7-naphthalenedicarboxylate, 4,4'-biphenyldicarboxylate, and 3,4'-biphenyldicarboxylate, further preferably one or more of diterephthalate, diisophthalate, and phthalate, and even more preferably diterephthalate.

[0050] According to the present invention, preferably, the diol monomer is a diol having the structure shown in formula (V),

[0051] R' can be an alkylene group, a cycloalkylene group, an ether alkyl group (for example, the diol monomer is diglycol), preferably a C2-C10 alkylene group or a C3-C10 cycloalkylene group. The diol monomer is preferably one or more of ethylene glycol, propylene glycol, butylene glycol, pentylene glycol, hexylene glycol, cyclohexanediol, and norbornanedimethanol, more preferably ethylene glycol and / or butylene glycol, and even more preferably ethylene glycol.

[0052] In the present invention, the dibasic acid monomer, dibasic alcohol monomer, component a, component b, and component c used for preparing the modified polyester can be commercially available products respectively, or can be prepared by the methods existing in the prior art, which are easy to synthesize and industrially produce.

[0053] According to the present invention, as described above, preferably, in the copolyester obtained by this method, the content of the structural unit A is 1-8 wt%, the content of the structural unit B is 0.1-2.5 wt%, the content of the structural unit C is 0.1-2.5 wt%, the content of the structural unit D is 68.5-81 wt%, and the content of the structural unit E is 16-25 wt%. More preferably, the content of the structural unit A is 1.5-6 wt%, the content of the structural unit B is 0.3-1 wt%, and the content of the structural unit C is 0.3-1 wt%.

[0054] According to the present invention, in order to obtain a modified polyester with better mechanical properties and anti-wrinkle properties, preferably, the molar ratio of the dibasic acid monomer to the dibasic alcohol monomer is 1:1.2-4; more preferably 1:1.5-2.5; based on 100 g of the dibasic acid monomer, the amount of the component a is 1.5-15 g, preferably 2.5-10 g; the amount of the component b is 0.2-3 g, preferably 0.5-1.5 g; the amount of the component c is 0.2-3 g, preferably 0.5-1.5 g.

[0055] According to the present invention, preferably, the dibasic acid monomer is a dibasic acid diester having the structure shown in formula (IV), the dibasic alcohol monomer is an aliphatic dibasic alcohol with C2-C10, the component a is a compound shown in formula (VI), the component b is an ester of the compound shown in formula (VII), and the component c is an ester of the compound shown in formula (VIII); at this time, component a (belonging to polyether siloxane diol) and the dibasic acid monomer form the structural unit F through transesterification reaction, component b and the dibasic alcohol monomer form the structural unit G through transesterification reaction, component c and the dibasic alcohol monomer form the structural unit H through transesterification reaction, and the dibasic acid monomer and the dibasic alcohol monomer form the structural unit J through transesterification reaction; and they are polymerized to form a modified polyester.

[0056]

[0057] According to the present invention, the modified polyester can be considered as a linear copolyester containing repeating segments of the structural unit F, repeating segments of the structural unit G, repeating segments of the structural unit H, and repeating segments of the structural unit J; in particular, a linear copolyester composed of repeating segments of the structural unit F, repeating segments of the structural unit G, repeating segments of the structural unit H, and repeating segments of the structural unit J.

[0058] The molecular weight and molecular weight distribution of the modified polyester are tested by gel permeation chromatography in the present invention. Preferably, the weight-average molecular weight of the modified polyester is 15,000-35,000 g / mol; the molecular weight distribution index is 1.5-2.0.

[0059] According to the present invention, the above preparation method will obtain a product of modified polyester, which contains a large amount of linear copolymer and a small amount of catalyst. Those skilled in the art can understand that the product of modified polyester is composed of a linear copolyester containing structural units A, B, C, D, and E and a catalyst. Preferably, the content of the catalyst in the product is 0.05-0.2 wt%. The content of the catalyst can be obtained by conversion after measuring the content of heavy metal elements in the catalyst.

[0060] According to the present invention, the polymerization process is to enable sufficient transesterification and polymerization reactions among the dibasic acid monomer, dibasic alcohol monomer, component a, component b, and component c. Preferably, the catalyst contains an antimony catalyst and a zinc catalyst; at this time, the modified polyester contains heavy metal elements introduced by the catalyst. Correspondingly, the content of heavy metal elements in the modified polyester corresponds to the catalyst content.

[0061] According to the present invention, preferably, the antimony catalyst is selected from one or more of antimony trioxide, antimony glycolate, and antimony acetate, more preferably antimony trioxide; the zinc catalyst is selected from one or more of zinc lactate, zinc acetate, and zinc isooctanoate, more preferably zinc acetate. The antimony catalyst and the zinc catalyst can be commercially available products or can be prepared by conventional methods, and their preparation methods will not be elaborated here.

[0062] According to the present invention, preferably, based on 100 g of the dibasic acid monomer, the dosage of the antimony catalyst is 0.02-0.5 g, more preferably 0.05-0.1 g; the dosage of the zinc catalyst is 0.02-0.5 g, more preferably 0.05-0.1 g. The antimony catalyst and the zinc catalyst within this dosage range have sufficient amounts to satisfy the progress of the polymerization reaction and promote the copolymerization of structural unit F segments, structural unit G segments, structural unit H segments, and structural unit J segments, and will not introduce excessive metal element content into the product of the modified polyester.

[0063] According to the present invention, preferably, the polymerization process includes: first performing a first-stage reaction under esterification reaction conditions, and then performing a second-stage reaction under polycondensation reaction conditions. Among them, the first-stage reaction is preferably carried out under an inert atmosphere, and the inert atmosphere can be provided by one or more of nitrogen, helium, neon, argon, etc.

[0064] According to the present invention, preferably, the esterification reaction conditions include: temperature of 190 - 210 °C, stirring rate of 130 - 170 rpm, and time of 3 - 4 h; the polycondensation reaction conditions include: temperature of 250 - 290 °C, stirring rate of 230 - 270 rpm.

[0065] According to the present invention, preferably, the process of the second - stage reaction includes: evacuating the reaction system after the first - stage reaction until the viscosity of the melt obtained from the first - stage reaction is 0.5 - 0.8 dL / g, to obtain a melt product that is transparent and has fewer bubbles.

[0066] In the present invention, the product obtained by polymerizing the dibasic acid monomer, dibasic alcohol monomer, component a, component b, and component c can be cooled and sliced to obtain the modified polyester.

[0067] The third aspect of the present invention provides the application of the above - mentioned modified polyester and / or the modified polyester prepared by the above - mentioned method in the preparation of polyester fibers.

[0068] The fourth aspect of the present invention provides a method for preparing polyester fibers, which includes: pre - crystallizing and drying the above - mentioned modified polyester and / or the modified polyester prepared by the above - mentioned method, and then performing melt - spinning to obtain a nascent raw filament, and collecting, drawing, and winding the nascent raw filament.

[0069] In the present invention, melt - spinning can be carried out using conventional spinning equipment, such as a screw extruder. Preferably, the temperature of the melt - spinning is 270 - 310 °C. Specifically, in the screw extruder, the melt temperature of the polyester screw is set to 270 - 310 °C, and the temperature of the spinning box is set to 270 - 310 °C.

[0070] According to the present invention, collection, drawing, and winding can also be carried out under conventional conditions in the art.

[0071] The polyester fibers prepared by the preparation method provided by the present invention have high mechanical properties, and have good softness and wrinkle - resistance. The elongation at break of the polyester fibers can be 25.5% or more, preferably 25.5 - 34.6%; the initial modulus can be 60 cN·dtex -1 hereinafter, preferably 50 - 60 cN·dtex -1 ; the maximum bending force of the tow (48 - filament) is 1. - 1.42 mN; and it is easy to recover after the tow is bent 90°.

[0072] The present invention will be described in detail below through examples.

[0073] In the following examples, the weight-average molecular weight and the molecular weight distribution index were determined by gel permeation chromatography (GPC). Among them, hexafluoroisopropanol (HFIP) was used as the solvent, and the measurement was carried out on a Waters-208 instrument (equipped with a Waters 2410 RI detector, a flow rate of 1.5 mL / min, and a temperature of 30 °C). The molecular weight was calibrated with a monodisperse linear polystyrene standard sample.

[0074] The content of each structural unit in the polyester can be determined by 1 1H-NMR and elemental analysis. The content of structural unit A is obtained by first detecting the content of silicon element in the polyester and then converting it through the molecular weight of structural unit A; the content of structural unit B can be obtained by first detecting the content of sulfur element in the polyester and then converting it through the molecular weight of structural unit B; the content of structural unit C can be obtained by first detecting the content of nitrogen element in the polyester and then converting it through the molecular weight of structural unit C. 1 The specific measurement device and conditions for 1H-NMR are as follows: Nuclear magnetic resonance device model: Bruker 400 MHz nuclear magnetic resonance spectrometer; Deuterated solvent: Deuterated chloroform, trifluoroacetic acid. 1 In the 1H-NMR spectrum, the signals near 2.9 ppm and 8.2 ppm are attributed to methylene and aryl hydrogen respectively. The contents of methylene and aryl hydrogen are obtained from their integral values, and combined with the contents of methylene and aryl hydrogen in structural unit A, structural unit B and structural unit C, the contents of structural unit D and structural unit E in the polyester are calculated.

[0075] The viscosity was measured with an Ubbelohde viscometer; the breaking strength and elongation at break were measured with a single-filament strength tester (in accordance with GB / T 14337-2008-T "Test Method for Tensile Properties of Chemical Fiber Staple Fibers"); the initial modulus was calculated from the stress-strain curve of the fiber; the maximum bending force of the tow was measured by passing a tow formed by 48 fibers through a fiber bending force tester (in accordance with the industry standard FZT 50059-2022 "Test Method for Bending Resistance of Synthetic Fiber Monofilaments"); the ease of bending recovery of the tow was determined by bending a tow formed by 48 fibers to 90° and holding for 5 s and then releasing it, and observing the recovery state of instantaneously springing back after release through a microscope to see if it could return to the original position.

[0076] In the following examples, unless otherwise specified, the raw materials and reagents used are all conventional commercially available products.

[0077] Example 1

[0078] Dimethyl terephthalate (dicarboxylic acid monomer, 100 g), ethylene glycol (diol monomer), and (Component a, purchased from Shandong Shengyilong Chemical Co., Ltd., product model 20cs), (Component b, purchased from Shanghai Haohong Biopharmaceutical Technology Co., Ltd., product number 1031810), (Component c, synthesized by Shanghai Nafu Biotechnology Co., Ltd.), antimony trioxide and zinc acetate were added to make the molar ratio of the dibasic acid monomer to the diol monomer 1:2. The dosage of component a was 2.5 wt% of the weight of the dibasic acid monomer, the dosages of component b and component c were each 1 wt% of the weight of the dibasic acid monomer, the dosage of zinc acetate was 0.07 wt% of the weight of the dibasic acid monomer, and the dosage of antimony trioxide was 0.07 wt% of the weight of the dibasic acid monomer. Nitrogen was continuously introduced into the reaction device, the stirrer was started (rotation speed 150 rpm), and the temperature was raised to 200 °C for reaction for 3.5 h. Subsequently, the temperature of the polymerization system was raised to 270 °C, the stirring speed was adjusted to 250 rpm, nitrogen was turned off, and the system was evacuated. When the stirring speed in the reaction device dropped to 100 rpm (the viscosity of the melt was 0.63 dL / g), the evacuation operation was ended, the stirrer was turned off, the material was discharged, cooled, and pelletized to obtain modified polyester chips.

[0079] The nuclear magnetic resonance hydrogen spectrum of the modified polyester prepared in Example 1 is as Figure 4 shown.

[0080] Example 2

[0081] The modified polyester chips were prepared according to the method of Example 1, except that the dosage of component a was replaced with: the dosage of component a was 5 wt% of the weight of the dibasic acid monomer.

[0082] The nuclear magnetic resonance hydrogen spectrum of the modified polyester prepared in Example 2 is as Figure 5 shown.

[0083] Example 3

[0084] The modified polyester chips were prepared according to the method of Example 1, except that the dosage of component a was replaced with: the dosage of component a was 10 wt% of the weight of the dibasic acid monomer.

[0085] The nuclear magnetic resonance hydrogen spectrum of the modified polyester prepared in Example 3 is as Figure 6 shown.

[0086] Example 4

[0087] Dimethyl isophthalate (dibasic acid monomer, 100 g), ethylene glycol (diol monomer), (Component a), (Component b), (Component c), antimony trioxide and zinc acetate were added, such that the molar ratio of the dibasic acid monomer to the diol monomer was 1:1.5. The dosage of component a was 5 wt% of the weight of the dibasic acid monomer, the dosages of component b and component c were 0.5 wt% of the weight of the dibasic acid monomer respectively, the dosage of zinc acetate was 0.05 wt% of the weight of the dibasic acid monomer, and the dosage of antimony trioxide was 0.05 wt% of the weight of the dibasic acid monomer. Nitrogen was continuously introduced into the reaction device, the stirrer was started (rotation speed: 130 rpm), and the temperature was raised to 190 °C for reaction for 4 h. Subsequently, the temperature of the polymerization system was raised to 250 °C, the stirring speed was adjusted to 270 rpm, nitrogen was turned off, and the system was evacuated. When the stirring speed in the reaction device dropped to 100 rpm (viscosity of the melt: 0.64 dL / g), the evacuation operation was terminated, the stirrer was turned off, and the product was discharged, cooled and pelletized to obtain the modified polyester chips.

[0088] Example 5

[0089] Dimethyl terephthalate (dibasic acid monomer, 100 g), butanediol (diol monomer) were added to the reaction device in proportion, (Component a), (Component b), (Component c), antimony trioxide and zinc acetate were added, such that the molar ratio of the dibasic acid monomer to the diol monomer was 1:2.5. The dosage of component a was 10 wt% of the weight of the dibasic acid monomer, the dosages of component b and component c were 1.5 wt% of the weight of the dibasic acid monomer respectively, the dosage of zinc acetate was 0.1 wt% of the weight of the dibasic acid monomer, and the dosage of antimony trioxide was 0.1 wt% of the weight of the dibasic acid monomer. Nitrogen was continuously introduced into the reaction device, the stirrer was started (rotation speed: 170 rpm), and the temperature was raised to 210 °C for reaction for 3 h. Subsequently, the temperature of the polymerization system was raised to 290 °C, the stirring speed was adjusted to 230 rpm, nitrogen was turned off, and the system was evacuated. When the stirring speed in the reaction device dropped to 100 rpm (viscosity of the melt: 0.56 dL / g), the evacuation operation was terminated, the stirrer was turned off, and the product was discharged, cooled and pelletized to obtain the modified polyester chips.

[0090] Example 6

[0091] The modified polyester chips were prepared according to the method of Example 1, except that component a was replaced with (Synthesized by Shanghai Nafu Biotechnology Co., Ltd.).

[0092] Example 7

[0093] The modified polyester chips were prepared according to the method of Example 1, except that component b was replaced with (Synthesized by Shanghai Nafu Biotechnology Co., Ltd.).

[0094] Example 8

[0095] Prepare the modified polyester chips according to the method of Example 1, except that component c is replaced with (synthesized by Shanghai Nafu Biotechnology Co., Ltd.).

[0096] Example 9

[0097] Prepare the modified polyester chips according to the method of Example 1, except that component c is replaced with (synthesized by Shanghai Nafu Biotechnology Co., Ltd.).

[0098] Example 10

[0099] Prepare the modified polyester chips according to the method of Example 1, except that the molar ratio of the diacid monomer to the diol monomer is 1:1.2.

[0100] Example 11

[0101] Prepare the modified polyester chips according to the method of Example 1, except that the molar ratio of the diacid monomer to the diol monomer is 1:4.

[0102] Example 12

[0103] Prepare the modified polyester chips according to the method of Example 1, except that components b and c are 3 wt% of the weight of the diacid monomer respectively.

[0104] Example 13

[0105] Prepare the modified polyester chips according to the method of Example 1, except that components b and c are 0.2 wt% of the weight of the diacid monomer respectively.

[0106] Example 14

[0107] Prepare the modified polyester chips according to the method of Example 1, except that antimony trioxide is replaced with antimony glycolate, and the amount of antimony glycolate used is 0.02 wt% of the weight of the diacid monomer.

[0108] Example 15

[0109] Prepare the modified polyester chips according to the method of Example 1, except that zinc acetate is replaced with zinc lactate, and the amount of zinc lactate used is 0.5 wt% of the weight of the diacid monomer.

[0110] Comparative Example 1

[0111] Add dimethyl terephthalate (diacid monomer, 100 g), ethylene glycol (diol monomer) to the reaction device in proportion, (Component A), antimony trioxide and zinc acetate are used, such that the molar ratio of the dibasic acid monomer to the diol monomer is 1:2. The dosage of Component A is 2.5 wt% of the weight of the dibasic acid monomer, the dosage of zinc acetate is 0.05 wt% of the weight of the dibasic acid monomer, and the antimony trioxide is 0.05 wt% of the weight of the dibasic acid monomer. Nitrogen is continuously introduced into the reaction device, a condensation device is installed, the stirrer is started (rotation speed is 150 rpm), and the temperature is raised to 200 °C for reaction for 3.5 h. Subsequently, the temperature of the polymerization system is raised to 270 °C, the stirring speed is adjusted to 250 rpm, nitrogen is turned off, the system is evacuated, and when the stirring speed drops to 100 rpm (the viscosity of the melt is 0.78 dL / g), the evacuation operation is ended, the stirrer is turned off, the material is discharged, cooled, and pelletized to obtain modified polyester chips.

[0112] Comparative Example 2

[0113] Dimethyl terephthalate (dibasic acid monomer, 100 g), ethylene glycol (diol monomer) are added to the reaction device in proportion, (Component B), (Component C), antimony trioxide and zinc acetate are used, such that the molar ratio of the dibasic acid monomer to the diol monomer is 1:2. Component B and Component C are respectively 1 wt% of the weight of the dibasic acid monomer, the dosage of zinc acetate is 0.05 wt% of the weight of the dibasic acid monomer, and the antimony trioxide is 0.05 wt% of the weight of the dibasic acid monomer. Nitrogen is continuously introduced into the reaction device, the stirrer is started (rotation speed is 150 rpm), and the temperature is raised to 190 °C for reaction for 4 h. Subsequently, the temperature of the polymerization system is raised to 250 °C, the stirring speed is adjusted to 270 rpm, nitrogen is turned off, the system is evacuated, and when the stirring speed drops to 100 rpm (the viscosity of the melt is 0.65 dL / g), the evacuation operation is ended, the stirrer is turned off, the material is discharged, cooled, and pelletized to obtain modified polyester chips.

[0114] Comparative Example 3

[0115] Dimethyl terephthalate (dibasic acid monomer, 100 g), ethylene glycol (diol monomer) are added to the reaction device in proportion, (Component A), (Component B), antimony trioxide and zinc acetate were used, such that the molar ratio of the dibasic acid monomer to the diol monomer was 1:2. The dosage of Component A was 2.5 wt% of the weight of the dibasic acid monomer, Component B was 1 wt% of the weight of the dibasic acid monomer, the dosage of zinc acetate was 0.05 wt% of the weight of the dibasic acid monomer, and antimony trioxide was 0.05 wt% of the weight of the dibasic acid monomer. Nitrogen was continuously introduced into the reaction device, the stirrer was started (rotation speed: 150 rpm), and the temperature was raised to 200 °C for reaction for 3.5 h. Subsequently, the temperature of the polymerization system was raised to 270 °C, the stirring speed was adjusted to 250 rpm, nitrogen was turned off, and the system was evacuated. When the stirring speed in the reaction device dropped to 100 rpm (viscosity of the melt: 0.63 dL / g), the evacuation operation was ended, the stirrer was turned off, and the product was discharged, cooled, and pelletized to obtain modified polyester chips.

[0116] Test Example 1

[0117] The yields, catalyst contents, weight-average molecular weights, and molecular weight distribution indices of the modified polyester chips prepared in Examples 1 - 15 and Comparative Examples 1 - 3 were measured, and the results are shown in Table 1. Also, the contents of the chain segment structures of each polymer structural unit in the modified polyester were measured, and the results are shown in Table 2.

[0118] Table 1

[0119] [[ID=Thirteen]]

[0120] Table 2

[0121]

[0122]

[0123] Test Example 2

[0124] Using commercially available conventional polyester as a reference, the viscosities, elongation at break, breaking strength, and initial modulus of the modified polyesters prepared in Examples 1 - 15 and Comparative Examples 1 - 3 and the conventional polyester were measured, and the results are shown in Table 3.

[0125] Modified polyester fibers were prepared using the modified polyester chips prepared in Examples 1 - 15 and Comparative Examples 1 - 3: The modified polyester chips were pre-crystallized and dried, and the dried modified polyester chips were added to a screw extruder for melt spinning. The melt temperature of the polyester screw was 290 °C, and the temperature of the spinning box was 290 °C to obtain nascent filaments; the filaments were bundled, drawn, and wound to obtain modified polyester fibers.

[0126] The maximum bending force of the tow and the ease of recovery after the tow was bent by 90° of the modified polyester fibers corresponding to Examples 1 - 15 and Comparative Examples 1 - 3 and the conventional polyester fibers were measured, and the results are shown in Table 3.

[0127] Table 3

[0128]

[0129] As can be seen from Table 3, compared with conventional polyester, the modified polyester fibers prepared in Examples 1 - 15 have obvious changes in performance parameters such as viscosity, elongation at break, breaking strength, initial modulus, maximum bending force, ease of recovery after bending, etc. It can be seen from Examples 1 - 3 that when the dosages of Component b and Component c are certain, as the dosage of the flexible chain segment of Component a hydroxy silicone oil increases, the breaking strength, initial modulus (0 - 1% modulus), and maximum bending force of the modified polyester fiber all gradually decrease, while the elongation at break gradually increases, the softness of the modified polyester fiber improves, and the fiber is easy to recover after being bent. It can be seen from Example 1 and Comparative Example 1 that if only Component a hydroxy silicone oil flexible monomer is added to the polymerization system, compared with conventional polyester fiber, the elongation at break of the modified polyester fiber increases, the initial modulus and maximum bending force gradually decrease, the softness improves, but the fiber is difficult to recover after being bent, and the wrinkle resistance decreases; it can be seen from Example 1 and Comparative Example 2 that if Component a (hydroxy silicone oil flexible monomer) is not added to the polymerization system and only Component b and Component c (anti-wrinkle modification monomer cation-anion pair) are added, the initial modulus of the modified polyester fiber increases and the softness decreases; it can be seen from Example 1 and Comparative Example 3 that if Component a (hydroxy silicone oil) and Component b (sodium sulfonate) are added to the polymerization system, due to the inability to form ionic pair forces, the initial modulus and maximum bending force of the modified polyester fiber decrease, but the polyester fiber is difficult to recover after being bent, and the wrinkle resistance decreases.

[0130] Test Example 3

[0131] The TGA curves of the modified polyester chips and conventional polyester (PET) prepared in Examples 1 - 3 were measured (instrument: Netzsch TG209F3, heating rate: 10 °C / min, test temperature range: 30 - 800 °C), and the results are shown in Figure 2 ( Figure 2 where a is conventional polyester, b is Example 1, c is Example 2, and d is Example 3), as the dosage of Component a (hydroxy silicone oil soft chain segment monomer) increases, the heat resistance of the modified polyester chips prepared in Examples 1 - 3 has no obvious difference from that of conventional polyester, and the modified polyester chips can withstand the spinning temperature and are not easily degraded.

[0132] The DSC curves of the modified polyester chips and conventional polyester (PET) prepared in Examples 1 and 2 were measured (instrument: Netzsch DSC 204F1, heating rate: 10 °C / min, test temperature range: 30 - 300 °C), and the results are shown in Figure 3 ( Figure 3Among them, a is a conventional polyester, b is Example 1, and c is Example 2). As the dosage of component a (hydroxy silicone oil soft segment monomer) increases, the melting points of the modified polyester chips prepared in Example 1 and Example 2 gradually decrease.

[0133] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the technical concept scope of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A modified polyester, characterized in that, The modified polyester contains structural unit A represented by formula (I), structural unit B represented by formula (II), and structural unit C represented by formula (III); Wherein, R1, R2, R3, R4, R5, R6 are each independently a C1-C10 alkyl group, m, n, p are each independently a positive integer from 1 to 10; R I , R II , R III , R a , R b , R c , R d are each independently hydrogen or a C1-C10 alkyl group; M is sodium or potassium; X is fluorine, chlorine, bromine or iodine.

2. The modified polyester according to claim 1, wherein In the modified polyester, the content of the structural unit A is 1-8 wt%, the content of the structural unit B is 0.1-2.5 wt%, and the content of the structural unit C is 0.1-2.5 wt%; Preferably, in the modified polyester, the content of the structural unit A is 1.5-7 wt%, the content of the structural unit B is 0.3-1 wt%, and the content of the structural unit C is 0.3-1 wt%.

3. The modified polyester according to claim 1 or 2, wherein The modified polyester further contains structural unit D represented by formula (IV) and structural unit E represented by formula (V); Wherein, Ar is a group having a benzene ring, a naphthalene ring or an anthracene ring; R' is a C2-C10 alkylene group or a C3-C10 cycloalkylene group; Preferably, in the modified polyester, the content of the structural unit D is 68.5-81 wt%; the content of the structural unit E is 16-25 wt%.

4. The modified polyester according to claim 3, wherein R1, R2, R3, R4, R5 and R6 are the same substituents, preferably C1-C4 alkyl groups, more preferably methyl or ethyl; R I , R II , R III are the same substituents, preferably hydrogen or C1-C4 alkyl groups, more preferably hydrogen or methyl; R a , R c , R d are the same substituents, preferably hydrogen or C1-C4 alkyl groups, more preferably hydrogen or methyl; R b is a C1-C4 alkyl group, more preferably methyl or ethyl; Ar is a group having a benzene ring.

5. A method for preparing a modified polyester, characterized in that, The method includes the following steps: in the presence of a catalyst, mixing a dibasic acid monomer, a diol monomer, component a, component b and component c for polymerization; The component a is a compound having the structure shown in formula (I), the component b is a compound having the structure shown in formula (II), and the component c is a compound having the structure shown in formula (III), Among them, R1, R2, R3, R4, R5, and R6 are each independently a C1-C10 alkyl group, m, n, and p are each independently a positive integer from 1 to 10; R I , R II , R III , R a , R b , R c , R d are each independently hydrogen or a C1-C10 alkyl group; M is sodium or potassium; X is fluorine, chlorine, bromine, or iodine.

6. The preparation method according to claim 5, wherein R1, R2, R3, R4, R5 and R6 are the same substituents, preferably C1-C4 alkyl groups, more preferably methyl or ethyl; R I , R II , R III are the same substituents, preferably hydrogen or C1-C4 alkyl groups, more preferably hydrogen or methyl; R a , R c , R d are the same substituents, preferably hydrogen or C1-C4 alkyl groups, more preferably hydrogen or methyl; R b is a C1-C4 alkyl group, more preferably methyl or ethyl; Preferably, the dicarboxylic acid monomer is one or more of a dicarboxylic acid having the structure shown in formula (IV), an acid anhydride of the dicarboxylic acid, and an ester of the dicarboxylic acid. Formula (IV), Ar is a group having a benzene ring, a naphthalene ring or an anthracene ring; more preferably one or more of dimethyl isophthalate, dimethyl terephthalate, dimethyl phthalate, dimethyl 2,6-naphthalenedicarboxylate, dimethyl 1,5-naphthalenedicarboxylate, dimethyl 2,7-naphthalenedicarboxylate, dimethyl 4,4'-biphenyldicarboxylate and dimethyl 3,4'-biphenyldicarboxylate; further preferably one or more of dimethyl terephthalate, dimethyl isophthalate and dimethyl phthalate. Preferably, the diol monomer is a diol having the structure shown in formula (V). Formula (V), R' is one or more of C2-C10 alkylene, C3-C10 cycloalkylene; more preferably one or more of ethylene glycol, propylene glycol, butylene glycol, pentylene glycol, hexylene glycol and cyclohexanediol, and further preferably ethylene glycol and / or butylene glycol.

7. The preparation method according to claim 5 or 6, characterized in that, The molar ratio of the amount of the dibasic acid monomer to the amount of the diol monomer is 1:1.2-4; preferably 1:1.5-2.5; Preferably, based on 100 g of the dibasic acid monomer, the amount of the component a is 1.5-15 g, more preferably 2.5-10 g; the amount of the component b is 0.2-3 g, more preferably 0.5-1.5 g; the amount of the component c is 0.2-3 g, more preferably 0.5-1.5 g; Preferably, the catalyst contains an antimony catalyst and a zinc catalyst; Preferably, the antimony catalyst is selected from one or more of antimony trioxide, antimony glycolate and antimony acetate, more preferably antimony trioxide; the zinc catalyst is selected from one or more of zinc lactate, zinc acetate and zinc isooctanoate, more preferably zinc acetate; Preferably, based on 100 g of the dibasic acid monomer, the amount of the antimony catalyst is 0.02-0.5 g, more preferably 0.05-0.1 g; the amount of the zinc catalyst is 0.02-0.5 g, more preferably 0.05-0.1 g.

8. The preparation method according to claim 5 or 6, characterized in that, The process of the polymerization includes: first carrying out a first-stage reaction under esterification reaction conditions, and then carrying out a second-stage reaction under polycondensation reaction conditions; Preferably, the first-stage reaction is carried out under an inert atmosphere; Preferably, the esterification reaction conditions include: temperature is 190-210 °C, stirring rate is 130-170 rpm, and time is 3-4 h; Preferably, the polycondensation reaction conditions include: temperature is 250-290 °C, stirring rate is 230-270 rpm; The process of the second-stage reaction includes: evacuating the reaction system after the first-stage reaction until the viscosity of the melt obtained from the first-stage reaction is 0.5 - 0.8 dL / g.

9. Use of the modified polyester according to any one of claims 1 to 4 and / or the modified polyester prepared by the method according to any one of claims 5 to 8 in the preparation of polyester fibers.

10. A method for preparing polyester fiber, characterized in that, The method includes: subjecting the modified polyester according to any one of claims 1 to 4 and / or the modified polyester prepared by the method according to any one of claims 5 to 8 to pre-crystallization drying and then performing melt spinning to obtain a primary raw filament, and collecting, stretching, and winding the primary raw filament; Preferably, the temperature of the melt spinning is 270 - 310 °C.

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