A method for producing polyester fibers that suppresses the generation of microplastics during use

Abstract

The present invention aims to provide a method for producing polyester fibers that suppress microplastic generation during use. In this invention, polyester and a self-healing polymer are mixed in a predetermined ratio, followed by processes such as melt extrusion, cooling, solidification, oil application, and drawing to produce polyester fibers that generate low microplastics. The self-healing polymer is composed of ionic polyester segments, nonionic polyester segments, and polysiloxane segments, with all heterogeneous and homogeneous segments connected by ester bonds, and both ends of the polysiloxane segments modified with hydroxyl groups. This invention develops a novel polyester fiber material with self-healing properties that improves the abrasion resistance of the fiber material while exhibiting self-healing properties in response to fiber damage that may occur during use, significantly suppressing the generation of microplastics.

Description

[Technical Field]

[0001] The present invention relates to the field of polyester fibers, and more particularly to a method for producing polyester fibers that suppress the generation of microplastics during use. [Background technology]

[0002] Polyester fiber plays an important role in the national economy as a key raw material for the textile industry. However, with growing environmental awareness in recent years, it has become clear that 60% of microplastics in freshwater environments originate from clothing washing. During washing, ultrafine fibers are shed, which then pass through wastewater treatment facilities and ultimately enter large bodies of water, such as lakes and ponds. While natural fabric clothing also sheds fibers in washing machines and dryers, these fibers can be digested by microorganisms. Synthetic textile fibers are not biodegradable and can persist in ecosystems for centuries. When microplastic particles enter the natural environment, they not only disrupt ecosystems but also cause physical damage when ingested by aquatic and marine organisms. Furthermore, their persistent nature can lead to bioaccumulation, ultimately posing a risk to human health through the food chain.

[0003] Generally, plastic particles less than 5 mm in diameter are defined as microplastics, and those derived from textile products are referred to as fibrous microplastics. Fibrous microplastics are the main form of microplastics classified as environmental pollutants, and are a major source of pollution, particularly in oceans, riverbanks, and coastal areas. These fine fibers originate primarily from commercial and domestic laundry and other cleaning processes for textile products such as clothing, bedding, soft furnishings, and carpets. Therefore, the development of technology to prevent shedding during washing of polyester fiber, the basic textile material, is considered an important research topic.

[0004] When researching methods to reduce fibrous microplastics, it is essential to understand their primary generation mechanism. It is generally recognized that the primary sources of fibrous microplastics are the physical abrasion and washing process that textile products undergo during use. Specifically, during the washing process, textile materials are subjected to thermal and mechanical stress, which induces surface damage, breakage, and shedding of fibers. This results in the generation of microplastics in the form of loose fibers within textiles, broken fibers from fiber ends, and abrasion particles formed on the fiber surface.

[0005] The journal Carbohydrate Polymers reports a technology that applies a protective coating to polyimide fiber fabrics to solve the problems of surface abrasion and the massive shedding of fibrous microplastics caused by mechanical stress during washing. Chinese Patent CN114364830A discloses environmentally friendly polyester fiber and microfiber shedding prevention processing technology, including a method for producing core-sheath bicomponent fibers such as polyester coated with anti-shedding additives, including lubricants, impact modifiers, crosslinking agents, chain extenders, and crystal modifiers. Furthermore, Chinese Patent CN113668096A proposes a method for spinning core-sheath fibers from a functional masterbatch prepared by mixing and condensation polymerization of a branched esterification product and a hydroxyl-terminated polysiloxane, and polyester. The polysiloxane component in the sheath reduces the fiber's coefficient of friction and improves its abrasion resistance.

[0006] An analysis of existing technological trends reveals that the main approaches to reducing fibrous microplastics can be summarized into three methods: (1) surface protection through coating treatment, (2) improving the strength of the spinning melt, and (3) enhancing abrasion resistance by reducing the coefficient of friction on the fiber surface. As a complementary approach, there have also been reports of the development of biodegradable polyester fibers that can be rapidly decomposed even after they fall off during washing. However, current biodegradable polyester fibers have inherent issues: they have lower mechanical strength than general-purpose polyester fibers, so they easily generate fiber fragments during initial use, and they are unable to decompose under non-composting conditions such as deep-sea environments.

[0007] This invention develops a new polyester fiber material with self-repairing properties, which improves the abrasion resistance of the fiber material while also exhibiting self-repairing properties in response to fiber damage that may occur during use, significantly reducing the generation of microplastics. Summary of the Invention [Problem to be solved by the invention]

[0008] To solve the problems of the prior art, the present invention provides a method for producing a polyester fiber that suppresses microplastic generation during use. In this method, polyester and a self-healing polymer are mixed in a predetermined ratio, followed by processes such as melt extrusion, cooling, solidification, oil application, and drawing to produce a polyester fiber that generates low microplastics. The self-healing polymer is composed of ionic polyester segments, nonionic polyester segments, and polysiloxane segments, and is produced by synthesizing nonionic polyester segments and ionic polyester segments through an esterification reaction, followed by a polycondensation reaction. This method not only reduces the friction coefficient of polyester fibers, but also reliably achieves the self-healing function of the fibers when damage occurs. [Means for solving the problem]

[0009] To achieve the above object, the present invention adopts the following technical configurations: (1) After mixing polyester and a self-healing polymer, processes such as melt extrusion, cooling, solidification, application of oil, and stretching are carried out sequentially to produce polyester fibers that suppress the generation of microplastics during use.

[0010] (2) The self-healing polymer has an ordered block copolymer structure, consisting of nonionic polyester segments, ionic polyester segments, and polysiloxane segments, with all of the heterogeneous and homogeneous segments connected by ester bonds.

[0011] (3) Both ends of the polysiloxane segment are modified with hydroxyl groups.

[0012] Preferably, in the method for producing a polyester fiber that suppresses generation of microplastics during use, (1) The polyester to be spun is polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, or a modified copolyester. Furthermore, the mass fraction of the polyester in the modified copolyester is 80% or more, and the intrinsic viscosity of any of the polyesters is 0.60 to 1.25 dL / g.

[0013] (2) The self-healing polymer has a total number of segments of 5 to 12, an intrinsic viscosity of 0.40 to 0.80 dl / g, and a half-crystallization time t 1 / 2 It has a crystallization time of 1.5 to 5.0 min and a crystallization enthalpy of 20 to 40 J / g.

[0014] (3) The number of repeating units of the nonionic polyester segment is 4 to 10, the number of repeating units of the ionic polyester segment is 2 to 8, and the number of repeating units of the polysiloxane segment is 2 to 10. Controlling the chain length of these segments affects the structure and performance of the self-healing polymer; if the number of repeating units of each segment is outside the specified range, the structural order of the self-healing polymer and its thermal properties and processability will deteriorate, resulting in a decrease in the self-healing ability of the resulting fiber and a decrease in its microplastic suppression effect. Among these, when the number of repeating units of the nonionic polyester segment is less than 4, it becomes a simple ester of dicarboxylic acid and glycol, i.e., a short sequence unit, and therefore the number of segments increases at the same molecular weight, thereby increasing the randomness of the resulting polymer. On the other hand, when the number of repeating units is more than 10, the terminal reactivity decreases, resulting in a decrease in the copolymerization efficiency with the ionic segment. When the number of repeating units of the ionic polyester segment is less than 2, i.e., 1, the randomness of the resulting polymer increases. On the other hand, when the number of repeating units is more than 8, the self-repair ability of the resulting fiber after damage during use decreases. The effect of the number of repeating units of the polysiloxane segment on the self-repair ability of the fiber is similar to that of the ionic polyester segment.

[0015] In the method for producing polyester fibers that suppress the generation of microplastics during use, the self-repairing polymer is obtained by mixing a nonionic polyester and an ionic polyester synthesized by an esterification reaction with polysiloxane and polycondensing the mixture.

[0016] The nonionic polyester is prepared by esterification of dicarboxylic acid I and glycol I in a molar ratio of 1:1.05-1.50, where dicarboxylic acid I is terephthalic acid, isophthalic acid, or adipic acid; glycol I is ethylene glycol, 1,3-propanediol, 1,4-butanediol, or 1,5-pentanediol; the esterification catalyst is titanium ethylene glycol, tetrabutyl titanate, antimony ethylene glycol, antimony acetate, or antimony oxide, used in an amount of 10-100 ppm based on the mass of dicarboxylic acid I; and the esterification conditions are a temperature of 150-250°C, a pressure of 0.01-0.5 MPa, and a time of 1.5-3.5 hours.

[0017] The ionic polyester is prepared by two-stage esterification of dicarboxylic acid II and glycol II. In the first stage, the molar ratio of dicarboxylic acid II to glycol II is 1.05-1.50, and in the second stage, the amount of glycol II added is 0.1-0.6 times the moles of dicarboxylic acid II used in the first stage; dicarboxylic acid II is monosodium 5-sulfoisophthalate, sodium 2-sulfoterephthalate, or potassium 8-bis(2-hydroxyethoxy)carbonylanthraquinonephosphonate; glycol II is potassium 2,5-dihydroxybenzenesulfonate, N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid the catalyst for the two-stage esterification reaction is benzenesulfonic acid added during the first stage esterification reaction in an amount of 10 to 100 ppm based on the mass of dicarboxylic acid II; the conditions for the first stage esterification reaction are a temperature of 220 to 250°C, a pressure of 0.05 to 0.5 MPa, and a reaction time of 3.0 to 5.0 hours; and the conditions for the second stage esterification reaction are a temperature of 240 to 260°C, a pressure of 0.1 to 0.5 MPa, and a reaction time of 0.5 to 1.0 hours.

[0018] Based on the total mass of the nonionic polyester, ionic polyester, and polysiloxane, the amount of the ionic polyester added is 5 to 20%, and the amount of the polysiloxane added is 5 to 30%.

[0019] In the method for producing polyester fiber that suppresses microplastic generation during use, the polycondensation reaction is carried out in two steps: a pre-condensation step and a final condensation step, where the pre-condensation conditions are a temperature of 240-260°C, a time of 0.1-1.0 hours, and a pressure of 500-1000 Pa, and the final condensation conditions are a temperature of 260-285°C, a time of 1.5-3.0 hours, and a pressure of 0-100 Pa. The polycondensation catalyst is selected from tetrabutyl titanate, titanium ethylene glycol, diantimony trioxide, antimony ethylate, and antimony acetate, and the catalyst is added before the pre-condensation step in an amount of 50-500 ppm of the total weight of the ionic polyester and nonionic polyester.

[0020] In the method for producing polyester fibers that suppress the generation of microplastics during use, the amount of self-repairing polymer used is 1 to 10% by mass of the polyester.

[0021] In the method for producing polyester fiber that suppresses microplastic generation during use, the obtained polyester fiber that suppresses microplastic generation during use has the following performance characteristics: single fiber fineness of 1.5 to 5.0 dtex, oil-free fiber intrinsic viscosity drop of 0.02 to 0.10 dl / g (Note: oil-free fiber refers to fiber that has not been treated with an oil agent and has been subjected to a cooling and air-drying process after melt extrusion; the intrinsic viscosity drop indicates the difference in intrinsic viscosity of the oil-free polyester raw material and can reflect the thermal stability of the melt), breaking strength ≥ 4.5 cN / dtex, breaking elongation 15 to 35%, static friction coefficient ≤ 0.20, dynamic friction coefficient ≤ 0.40, self-repair speed 0.1 to 1.0 μm / min, and a 50 to 95% reduction in the amount of fibrous microplastics generated during washing compared to a product without the self-repairing polymer added. The principle of the present invention is as follows.

[0022] Previous techniques for reducing fibrous microplastics focused on three methods: (1) coating, (2) improving the strength of the spun melt, and (3) reducing the abrasion resistance of the fiber surface. However, coating methods have issues with durability and reduced flexibility, while adjusting the strength of the spun melt also has limitations. This invention develops a new polyester fiber material with self-repairing properties that improves the abrasion resistance of the fiber material while also demonstrating self-repair capabilities in response to fiber damage that may occur during use, significantly reducing the generation of microplastics.

[0023] The core of this invention is the introduction of a self-healing polymer into a polyester spinning melt. The polymer is composed of ionic polyester segments, nonionic polyester segments, and polysiloxane segments, and is polycondensed using a nonionic polyester and an ionic polyester synthesized by an esterification reaction. The ionic polyester segments, nonionic polyester segments, and polysiloxane segments are all low-molecular-weight hydroxyl-terminated intermediates. By controlling their blending ratio and optimizing the polymerization process, a copolymerized polyester with an ordered block structure is prepared. The ordered polymer chain structure and the self-healing polymer have a certain degree of crystallinity, thereby meeting the dry heat resistance requirements before spinning. The segments in the prepared self-healing polymer are all connected by ester bonds, and contain a large amount of ester-linked functional groups, ensuring excellent compatibility with the polyester melt used for spinning. The self-healing polymer has a high molecular weight, which allows it to exhibit excellent compatibility when mixed with a polyester melt, exhibiting the properties of an "alloy" structure, thereby maintaining good mechanical properties of the resulting fiber.

[0024] The self-healing polymer introduced into the polyester spinning melt in this invention is essentially an ionic polymer (also called an ionomer) with sulfonate or phosphate ionic bonds introduced into the polymer side chains. The main chain basic structural unit of an ionomer is typically composed of hydrophobic groups such as CHO. However, the introduction of hydrophilic ionic groups induces microphase separation between the ionomer main chain and the ionic side groups, forming nanoscale ionic clusters that function as physical crosslinking points. Within the molecular chain of an ionic polymer (ionomer), strong Coulomb forces act between ionic groups, resulting in microphase separation and the formation of nanoscale ionic clusters, which give ionomers their unique molecular chain structure and macroscopic properties. Physical crosslinking in ionomers significantly improves the polymer's melt strength, mechanical strength, toughness, tear resistance, and other properties. This physical crosslinking also has excellent properties. At low temperatures (usage temperatures), crosslinking forms a three-dimensional network structure, improving material performance. On the other hand, at high temperatures (processing temperatures), the aggregation of ion clusters is broken and the cross-linking effect is lost, making processing easier. The effect of ionic bonding improves the abrasion resistance of the fiber, and at the same time, if the spun fiber material is damaged by external washing or use, the strong Coulomb forces between the ionic groups in the self-healing polymer will self-repair the damaged area, thereby preventing further abrasion and suppressing the formation of fibrous microplastics.

[0025] The polysiloxane chain segments contained in self-healing polymers have low surface energy and excellent lubricity. Introducing them into textile materials reduces the frictional resistance of polyester fibers and improves their abrasion resistance. The addition of polysiloxane reduces the coefficient of friction of fibers, thereby reducing the likelihood of damage occurring between fibers or when the fibers come into contact with a washing machine. At the same time, the polysiloxane components localized on the fiber surface have excellent abrasion resistance and suppress the incidence of fiber breakage under the same mechanical stress. Additionally, the hydrophobic nature of polysiloxane reduces the contact area with water molecules during washing, slowing the rate of hydrolysis of ester bonds. This maintains fiber strength retention and reduces the amount of microplastics generated during the washing process.

[0026] In summary, the self-healing polymer introduced into the polyester spinning melt is composed of ionic polyester segments, nonionic polyester segments, and polysiloxane segments. The nonionic segments ensure compatibility with the spinning melt, while the ionic polyester segments form nanoscale ion pools, resulting in physical crosslinking. Strong Coulomb forces act between ionic groups within the ionomer molecular chain, resulting in microphase separation and nanoscale ion cluster formation, imparting unique molecular structure and physical properties. This physical crosslinking significantly improves the polymer's melt strength, mechanical strength, toughness, and tear resistance. The polysiloxane segments exhibit hydrophobicity and low friction, enhancing the fiber's ability to inhibit microplastic generation. The synergistic effect of these three segments maintains the self-healing polymer's crystallinity, ensures excellent miscibility with polyester, and ensures spinnability, effectively inhibiting microplastic generation during fiber use. [Effects of the Invention]

[0027] Advantages of the present invention include: (1) This invention involves co-blending the prepared self-healing polymer into polyester spinning melt to improve the fiber's ability to suppress microplastics. By combining enhanced abrasion resistance with the ability to self-repair in response to damage that may occur during use, the fiber significantly suppresses microplastic generation. The process is simple and flexible, and the self-healing polymer has an ordered polymer structure and a certain degree of crystallinity, meeting the dry heat resistance requirements prior to spinning.

[0028] (2) In the polyester fiber manufacturing method of the present invention, the self-repairing polymer is prepared by the transesterification reaction of an ionic polyester segment, a nonionic polyester segment, and a polysiloxane segment. The high density of ester-bonded functional groups in the molecular chain ensures excellent compatibility with polyester melts and spinnability. DETAILED DESCRIPTION OF THE INVENTION

[0029] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not deviate from the gist of the invention. Furthermore, even if a person skilled in the art is permitted to modify the present invention in various ways after reading the contents of the present invention, such modifications are also limited within the scope of the claims of the present invention as equivalent forms of the present invention.

[0030] The materials used in this invention are as follows: (1) Polysiloxane Supplier: Anhui Mingyi Silicon Industry Co., Ltd. Trademark: MY1203M (2) Modified copolyester Supplier: China Petrochemical Yizheng Chemical Fiber Co., Ltd. Trademark:HS550 Polyester content: 84wt% The conditions for the fiber forming process used in each example of the present invention, including melt extrusion, cooling, solidification, oil application, and drawing, are as follows: cooling air temperature 22°C, relative humidity 85%, air pressure 40 kPa, oil application rate 1.0%, heat roller GR1 speed 1250 m / min, temperature 95°C, heat roller GR2 speed 4200 m / min, temperature 125°C.

[0031] The test method adopted in this invention is as follows: (1) Half crystallization time t 1 / 2 Measurements are made using a DSC (Q-20 model) manufactured by TA, USA. The sample is vacuum dried at 135°C for 24 hours in advance, then heated from 25°C to 300°C at a heating rate of 10°C / min under a nitrogen atmosphere (heat history is removed by holding for 3 minutes), and then cooled from 300°C to 25°C. The DSC peak that appears during the cooling process is called the cooling crystallization peak, and the corresponding temperature is called the cooling crystallization temperature. The total time from the start to completion of crystallization is called the crystallization time, and the time corresponding to 50% crystallinity is called the half-crystallization time t 1 / 2 This becomes:

[0032] (2) Crystallization enthalpy DSC measurement is performed under the same conditions as in (1) above. The cooling crystallization process is an exothermic process, and the total amount of heat released per unit mass from the start to the end of crystallization is taken as the crystallization enthalpy.

[0033] (3) Intrinsic viscosity of oil-free yarn The characteristic viscosity of the ionic polyester masterbatch is measured according to GB / T 14190-2017. In the examples of the present invention, the mass ratio of phenol to 1,1,2,2-tetrachloroethane is 50:50.

[0034] (4) Breaking strength Conduct a breaking strength test in a dry state based on GB / T 14344-2008 "Test method for tensile properties of long chemical fibers."

[0035] (5) Breaking elongation The breaking elongation in a dry state is measured using the same standard as in (4) above.

[0036] (6) Coefficient of static friction Measurements are based on T / CSTM 00522-2022 "Test method for coefficient of friction of chemical fibers."

[0037] (7) Coefficient of kinetic friction The dynamic friction coefficient is measured using the same standard as in (6) above.

[0038] (8) Self-healing speed After creating an 8μm wide microcrack on the surface of the sample, the repair process was observed on a heated table at 80℃. The time it took for the crack width to return to 0μm was measured using a polarizing microscope, and the self-repair rate was calculated.

[0039] Example 1 The specific method for producing polyester fibers that suppress the generation of microplastics during use is as follows: (1) Under the conditions of a temperature of 250°C and a pressure of 0.5 MPa, terephthalic acid and ethylene glycol in a molar ratio of 1:1.05 are esterified for 1.5 hours to obtain non-ionic polyester. The esterification catalyst is titanium ethylene glycol, and its amount is 10 ppm of the mass of terephthalic acid.

[0040] (2) Ionic polyester is prepared by two-stage esterification of sodium 5-sulfoisophthalate and potassium 2,5-dihydroxybenzenesulfonate. The first stage of esterification is carried out at 220°C under 0.05 MPa pressure for 3 hours, and the second stage is carried out at 260°C under 0.1 MPa pressure for 0.8 hours. The molar ratio of the carboxyl groups of sodium 5-sulfoisophthalate to the hydroxyl groups of potassium 2,5-dihydroxybenzenesulfonate in the first stage of esterification is 1.05. The amount of potassium 2,5-dihydroxybenzenesulfonate added in the second stage of esterification is 0.1 times the moles of the sodium 5-sulfoisophthalate. Benzene sulfonic acid is also added as a catalyst in the first stage of esterification, at a dosage of 10 ppm of the mass of sodium 5-sulfoisophthalate.

[0041] (3) After mixing the nonionic polyester from step (1) with the ionic polyester and polysiloxane from step (2), tetrabutyl titanate is added and pre-condensation is carried out for 0.1 hours at a temperature of 240°C and a pressure of 1000 Pa, followed by final condensation for 1.5 hours at a temperature of 285°C and a pressure of 0 Pa to prepare a self-healing polymer. Based on the total mass of the nonionic polyester, ionic polyester, and polysiloxane, the amount of ionic polyester added is 15%, the amount of polysiloxane added is 30%, and the amount of condensation reaction catalyst added is 500 ppm of the total mass of the ionic polyester and nonionic polyester.

[0042] The obtained self-healing polymer has an ordered block copolymer structure, consisting of nonionic polyester segments, ionic polyester segments, and polysiloxane segments. Furthermore, the heterogeneous and homogeneous segments are all connected by ester bonds, both ends of which are modified with hydroxyl groups.

[0043] The obtained self-healing polymer had a total number of segments of 12, an intrinsic viscosity of 0.80 dl / g, and a half-crystallization time of t 1 / 2 The polymer has a crystallization enthalpy of 20 J / g and a melting point of 5.0 min, in which the number of repeating units of the nonionic polyester segment is 4, the number of repeating units of the ionic polyester segment is 6, and the number of repeating units of the polysiloxane segment is 10.

[0044] (4) Polyethylene terephthalate having an intrinsic viscosity of 0.60 dl / g is mixed with the self-healing polymer obtained in step (3), and then the mixture is melt-extruded, cooled, solidified, oiled, and stretched to produce polyester fibers that suppress microplastic generation during use. The amount of the self-healing polymer used is 1% of the polyester mass.

[0045] The resulting polyester fiber, which suppresses the generation of microplastics during use, has the following performance characteristics: single yarn fineness of 1.5 dtex, oil-free yarn intrinsic viscosity drop of 0.02 dl / g, breaking strength of 4.9 cN / dtex, breaking elongation of 15%, static friction coefficient of 0.20, dynamic friction coefficient of 0.40, self-repair speed of 0.1 μm / min, and a 50% reduction in the amount of fibrous microplastics generated during washing compared to a product without the self-repairing polymer added.

[0046] Example 2 The specific method for producing polyester fibers that suppress the generation of microplastics during use is as follows: (1) Under the conditions of a temperature of 240°C and a pressure of 0.4 MPa, isophthalic acid and 1,3-propanediol in a molar ratio of 1:1.50 are esterified for 3.5 hours to obtain a nonionic polyester. The esterification catalyst used is tetrabutyl titanate, and the amount added is 30 ppm of the mass of terephthalic acid.

[0047] (2) Ionic polyester was prepared by two-stage esterification of sodium 2-sulfoterephthalate and sodium N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate. The first stage esterification conditions were 250°C, 0.5 MPa, and 3.5 hours, and the second stage esterification conditions were 250°C, 0.2 MPa, and 0.6 hours. The molar ratio of carboxyl groups of sodium 2-sulfoterephthalate to hydroxyl groups of sodium N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate in the first stage esterification was 1.5. The amount of sodium N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate added in the second stage esterification was 0.2 times the moles of sodium 2-sulfoterephthalate. Benzene sulfonic acid catalyst was also added in the first stage esterification reaction at a dosage of 100 ppm of the mass of sodium 2-sulfoterephthalate.

[0048] (3) After mixing the nonionic polyester from step (1) with the ionic polyester and polysiloxane from step (2), add titanium ethylene glycol and carry out pre-condensation for 1 hour at a temperature of 260°C and a pressure of 500 Pa, and then carry out final condensation for 3 hours at a temperature of 280°C and a pressure of 100 Pa to prepare a self-healing polymer. Based on the total mass of the nonionic polyester, ionic polyester, and polysiloxane, the amount of ionic polyester added is 10%, the amount of polysiloxane added is 5%, and the amount of condensation reaction catalyst added is 50 ppm of the total mass of the ionic polyester and nonionic polyester.

[0049] The obtained self-healing polymer has an ordered block copolymer structure, consisting of nonionic polyester segments, ionic polyester segments, and polysiloxane segments. Furthermore, the heterogeneous and homogeneous segments are all connected by ester bonds, both ends of which are modified with hydroxyl groups.

[0050] The obtained self-healing polymer had a total number of segments of 5, an intrinsic viscosity of 0.40 dl / g, and a half-crystallization time t 1 / 2 The polymer has a crystallization enthalpy of 40 J / g and a crystallization time of 1.5 min, in which the number of repeating units of the nonionic polyester segment is 10, the number of repeating units of the ionic polyester segment is 4, and the number of repeating units of the polysiloxane segment is 2.

[0051] (4) Polytrimethylene terephthalate having an intrinsic viscosity of 0.90 dl / g is mixed with the self-healing polymer obtained in step (3), and then the mixture is melt-extruded, cooled, solidified, oiled, and stretched to produce polyester fibers that suppress microplastic generation during use. The amount of the self-healing polymer used is 10% of the polyester mass.

[0052] The resulting polyester fiber, which suppresses the generation of microplastics during use, has the following performance characteristics: single yarn fineness 5 dtex, oil-free yarn intrinsic viscosity drop 0.1 dl / g, breaking strength 4.5 cN / dtex, breaking elongation 35%, static friction coefficient 0.19, dynamic friction coefficient 0.36, self-repair speed 0.49 μm / min, and a 75% reduction in the amount of fibrous microplastics generated during washing compared to a product without the self-repairing polymer added.

[0053] Example 3 The specific method for producing polyester fibers that suppress the generation of microplastics during use is as follows: (1) Under the conditions of a temperature of 180°C and a pressure of 0.3 MPa, adipic acid and 1,4-butanediol in a molar ratio of 1:1.20 are esterified for 3.5 hours to obtain a nonionic polyester, in which the esterification catalyst is antimony ethylene glycol, and the amount added is 100 ppm of the mass of terephthalic acid.

[0054] (2) Ionic polyesters are prepared by two-step esterification of potassium 8-bis(2-hydroxyethoxy)carbonyl anthraquinonephosphonate and sodium 2-[tris(hydroxymethyl)methylamino]-1-ethanesulfonate. wherein the conditions for the first stage esterification reaction are temperature 230°C, pressure 0.1MPa, time 4 hours, and the conditions for the second stage esterification reaction are temperature 240°C, pressure 0.3MPa, time 0.5 hours; the molar ratio of the carboxyl group of 8-bis(2-hydroxyethoxy)carbonylanthraquinone potassium phosphonate to the hydroxyl group of 2-[tris(hydroxymethyl)methylamino]-1-ethanesulfonate sodium in the first stage esterification reaction is 1.15, the dosage of 2-[tris(hydroxymethyl)methylamino]-1-ethanesulfonate sodium added in the second stage esterification is 0.3 times the moles of the above 8-bis(2-hydroxyethoxy)carbonylanthraquinone potassium phosphonate, and the catalyst benzenesulfonic acid is also added in the first stage esterification reaction, and its dosage is 20 ppm of the mass of 8-bis(2-hydroxyethoxy)carbonylanthraquinone potassium phosphonate.

[0055] (3) After mixing the nonionic polyester from step (1) with the ionic polyester and polysiloxane from step (2), diantimony trioxide is added, and pre-condensation is carried out for 0.4 hours at a temperature of 245°C and a pressure of 900 Pa, followed by final condensation for 2 hours at a temperature of 275°C and a pressure of 80 Pa to prepare a self-healing polymer. Based on the total mass of the nonionic polyester, ionic polyester, and polysiloxane, the amount of ionic polyester added is 20%, the amount of polysiloxane added is 25%, and the amount of condensation reaction catalyst added is 400 ppm of the total mass of the ionic polyester and nonionic polyester.

[0056] The obtained self-healing polymer has an ordered block copolymer structure, consisting of nonionic polyester segments, ionic polyester segments, and polysiloxane segments. Furthermore, the heterogeneous and homogeneous segments are all connected by ester bonds, both ends of which are modified with hydroxyl groups.

[0057] The obtained self-healing polymer had a total number of segments of 12, an intrinsic viscosity of 0.60 dl / g, and a half-crystallization time of t 1 / 2 The polymer has a crystallization enthalpy of 23 J / g and a melting point of 4.1 min, in which the number of repeating units of the nonionic polyester segment is 5, the number of repeating units of the ionic polyester segment is 8, and the number of repeating units of the polysiloxane segment is 9.

[0058] (4) Polybutylene terephthalate having an intrinsic viscosity of 1.25 dL / g is mixed with the self-healing polymer obtained in step (3), and then the mixture is melt-extruded, cooled, solidified, oiled, and stretched to produce polyester fibers that suppress microplastic generation during use. The amount of the self-healing polymer used is 8% of the polyester mass.

[0059] The resulting polyester fiber, which suppresses the generation of microplastics during use, has the following performance characteristics: single yarn fineness of 4.3 dtex, oil-free yarn intrinsic viscosity drop of 0.09 dl / g, breaking strength of 4.8 cN / dtex, breaking elongation of 30%, static friction coefficient of 0.1, dynamic friction coefficient of 0.22, self-repair speed of 1 μm / min, and a 95% reduction in the amount of fibrous microplastics generated during washing compared to a product without the self-repairing polymer added.

[0060] Example 4 The specific method for producing polyester fibers that suppress the generation of microplastics during use is as follows: (1) Under the conditions of a temperature of 220°C and a pressure of 0.2 MPa, terephthalic acid and 1,5-pentanediol in a molar ratio of 1:1.15 are esterified for 3 hours to obtain a nonionic polyester. The esterification catalyst is antimony acetate, and its amount is 90 ppm of the mass of terephthalic acid.

[0061] (2) Ionic polyesters are prepared by two-step esterification of sodium 2-sulfoterephthalate and sodium 3-[N-tris(hydroxymethyl)methylamino]-2-hydroxypropanesulfonate. wherein the conditions for the first stage esterification reaction are temperature 245°C, pressure 0.4MPa, time 4 hours, and the conditions for the second stage esterification reaction are temperature 240°C, pressure 0.4MPa, time 1 hour; in the first stage esterification reaction, the molar ratio of the carboxyl group of 2-sulfoterephthalic acid-sodium to the hydroxyl group of 3-[N-tris(hydroxymethyl)methylamino]-2-hydroxypropanesulfonate sodium is 1.4, and the dosage of 3-[N-tris(hydroxymethyl)methylamino]-2-hydroxypropanesulfonate sodium added in the second stage esterification is 0.4 times the moles of the above-mentioned 2-sulfoterephthalic acid-sodium, and the catalyst benzenesulfonic acid is also added in the first stage esterification reaction, and its dosage is 80 ppm of the mass of 2-sulfoterephthalic acid-sodium.

[0062] (3) After mixing the nonionic polyester from step (1) with the ionic polyester and polysiloxane from step (2), antimony ethylene glycol is added, and pre-condensation is carried out for 0.8 hours at a temperature of 255°C and a pressure of 600 Pa. Final condensation is then carried out for 2.5 hours at a temperature of 270°C and a pressure of 20 Pa to prepare a self-healing polymer. Based on the total mass of the nonionic polyester, ionic polyester, and polysiloxane, the amount of ionic polyester added is 5%, the amount of polysiloxane added is 10%, and the amount of condensation reaction catalyst added is 100 ppm of the total mass of the ionic polyester and nonionic polyester.

[0063] The obtained self-healing polymer has an ordered block copolymer structure, consisting of nonionic polyester segments, ionic polyester segments, and polysiloxane segments. Furthermore, the heterogeneous and homogeneous segments are all connected by ester bonds, both ends of which are modified with hydroxyl groups.

[0064] The obtained self-healing polymer had a total number of segments of 6, an intrinsic viscosity of 0.50 dl / g, and a half-crystallization time of t 1 / 2 The polymer has the characteristics of a crystallization time of 2.2 min and a crystallization enthalpy of 37 J / g, in which the number of repeating units of the nonionic polyester segment is 9, the number of repeating units of the ionic polyester segment is 2, and the number of repeating units of the polysiloxane segment is 5.

[0065] (4) Polybutylene terephthalate having an intrinsic viscosity of 1.25 dL / g is mixed with the self-healing polymer obtained in step (3), and then the mixture is melt-extruded, cooled, solidified, oiled, and stretched to produce polyester fibers that suppress microplastic generation during use. The amount of the self-healing polymer used is 5% of the polyester mass.

[0066] The resulting polyester fiber, which suppresses the generation of microplastics during use, has the following performance characteristics: single yarn fineness of 2.9 dtex, oil-free yarn intrinsic viscosity drop of 0.05 dl / g, breaking strength of 4.7 cN / dtex, breaking elongation of 27%, static friction coefficient of 0.18, dynamic friction coefficient of 0.35, self-repair speed of 0.23 μm / min, and a 64% reduction in the amount of fibrous microplastics generated during washing compared to a product without the self-repairing polymer added.

[0067] Example 5 The specific method for producing polyester fibers that suppress the generation of microplastics during use is as follows: (1) Under the conditions of a temperature of 240°C and a pressure of 0.1 MPa, isophthalic acid and ethylene glycol in a molar ratio of 1:1.30 are esterified over 2 hours to obtain a nonionic polyester. The esterification catalyst is antimony oxide, and the amount added is 80 ppm of the mass of terephthalic acid.

[0068] (2) Ionic polyesters are prepared by two-step esterification of potassium 8-bis(2-hydroxyethoxy)carbonyl anthraquinonephosphonate and potassium 2,5-dihydroxybenzenesulfonate. wherein the conditions for the first stage esterification reaction are temperature 235°C, pressure 0.2MPa, time 4.5hr, and the conditions for the second stage esterification reaction are temperature 260°C, pressure 0.35MPa, time 0.7hr; the molar ratio of the carboxyl group of 8-bis(2-hydroxyethoxy)carbonyl anthraquinone potassium phosphonate to the hydroxyl group of 2,5-dihydroxybenzenesulfonate potassium in the first stage esterification reaction is 1.25, the amount of 2,5-dihydroxybenzenesulfonate potassium added in the second stage esterification is 0.5 times the amount of the above 8-bis(2-hydroxyethoxy)carbonyl anthraquinone potassium phosphonate, and the amount of catalyst benzenesulfonic acid added in the first stage esterification reaction is 40ppm of the mass of 8-bis(2-hydroxyethoxy)carbonyl anthraquinone potassium phosphonate.

[0069] (3) After mixing the nonionic polyester from step (1) with the ionic polyester and polysiloxane from step (2), antimony acetate is added and pre-condensation is carried out for 0.6 hours at a temperature of 250°C and a pressure of 800 Pa, followed by final condensation for 2.5 hours at a temperature of 265°C and a pressure of 60 Pa to prepare a self-healing polymer. Based on the total mass of the nonionic polyester, ionic polyester, and polysiloxane, the amount of ionic polyester added is 12%, the amount of polysiloxane added is 20%, and the amount of condensation reaction catalyst added is 300 ppm of the total mass of the ionic polyester and nonionic polyester.

[0070] The obtained self-healing polymer has an ordered block copolymer structure, consisting of nonionic polyester segments, ionic polyester segments, and polysiloxane segments. Furthermore, the heterogeneous and homogeneous segments are all connected by ester bonds, both ends of which are modified with hydroxyl groups.

[0071] The obtained self-healing polymer had a total number of segments of 8, an intrinsic viscosity of 0.70 dl / g, and a half-crystallization time of t 1 / 2 The polymer has the characteristics of a crystallization time of 2.7 min and a crystallization enthalpy of 33 J / g, in which the number of repeating units of the nonionic polyester segment is 8, the number of repeating units of the ionic polyester segment is 5, and the number of repeating units of the polysiloxane segment is 8.

[0072] (4) Polybutylene terephthalate having an intrinsic viscosity of 0.71 dL / g is mixed with the self-healing polymer obtained in step (3), and then the mixture is melt-extruded, cooled, solidified, oiled, and stretched to produce polyester fibers that suppress microplastic generation during use. The amount of the self-healing polymer used is 3% of the polyester mass.

[0073] The resulting polyester fiber, which suppresses the generation of microplastics during use, has the following performance characteristics: single yarn fineness 2.1 dtex, oil-free yarn intrinsic viscosity drop 0.03 dl / g, breaking strength 4.8 cN / dtex, breaking elongation 23%, static friction coefficient 0.16, dynamic friction coefficient 0.33, self-repair speed 0.34 μm / min, and a 72% reduction in the amount of fibrous microplastics generated during washing compared to a product without the self-repairing polymer added.

[0074] Example 6 The specific method for producing polyester fibers that suppress the generation of microplastics during use is as follows: (1) Under the conditions of a temperature of 150°C and a pressure of 0.01 MPa, adipic acid and 1,3-propanediol in a molar ratio of 1:1.40 are esterified for 2.5 hours to obtain a nonionic polyester. The esterification catalyst is antimony oxide, and the amount added is 25 ppm of terephthalic acid mass.

[0075] (2) Ionic polyester was prepared by two-stage esterification of monosodium 5-sulfoisophthalate and sodium N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate. The first stage was esterified at 240°C under 0.3 MPa for 5 hours, and the second stage was esterified at 250°C under 0.5 MPa for 0.9 hours. The molar ratio of carboxyl groups in monosodium 5-sulfoisophthalate to hydroxyl groups in sodium N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate in the first stage was 1.35. The amount of sodium N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate added in the second stage was 0.5 times the amount of monosodium 5-sulfoisophthalate. Benzene sulfonic acid catalyst was also added in the first stage, at a dosage of 60 ppm by mass of monosodium 5-sulfoisophthalate.

[0076] (3) After mixing the nonionic polyester from step (1) with the ionic polyester and polysiloxane from step (2), tetrabutyl titanate is added and pre-condensation is carried out for 0.5 hours at a temperature of 240°C and a pressure of 700 Pa, followed by final condensation for 2 hours at a temperature of 260°C and a pressure of 50 Pa to prepare a self-healing polymer. Based on the total mass of the nonionic polyester, ionic polyester, and polysiloxane, the amount of ionic polyester added is 18%, the amount of polysiloxane added is 15%, and the amount of condensation reaction catalyst added is 200 ppm of the total mass of the ionic polyester and nonionic polyester.

[0077] The obtained self-healing polymer has an ordered block copolymer structure, consisting of nonionic polyester segments, ionic polyester segments, and polysiloxane segments. Furthermore, the heterogeneous and homogeneous segments are all connected by ester bonds, both ends of which are modified with hydroxyl groups.

[0078] The obtained self-healing polymer had a total number of segments of 10, an intrinsic viscosity of 0.65 dl / g, and a half-crystallization time of t 1 / 2 The polymer has the characteristics of a crystallization time of 3.3 min and a crystallization enthalpy of 29 J / g, in which the number of repeating units of the nonionic polyester segment is 7, the number of repeating units of the ionic polyester segment is 7, and the number of repeating units of the polysiloxane segment is 6.

[0079] (4) Polybutylene terephthalate having an intrinsic viscosity of 1.10 dL / g is mixed with the self-healing polymer obtained in step (3), and then the mixture is melt-extruded, cooled, solidified, oiled, and stretched to produce polyester fibers that suppress microplastic generation during use. The amount of the self-healing polymer used is 6% of the polyester mass.

[0080] The resulting polyester fiber, which suppresses the generation of microplastics during use, has the following performance characteristics: single yarn fineness of 3.8 dtex, oil-free yarn intrinsic viscosity drop of 0.07 dl / g, breaking strength of 4.6 cN / dtex, breaking elongation of 29%, static friction coefficient of 0.15, dynamic friction coefficient of 0.31, self-repair speed of 0.55 μm / min, and an 86% reduction in the amount of fibrous microplastics generated during washing compared to a product without the self-repairing polymer added.

Claims

1. a dicarboxylic acid II selected from monosodium 5-sulfoisophthalate, sodium 2-sulfoterephthalate, or potassium 8-bis(2-hydroxyethoxy)carbonyl anthraquinone phosphonate; and a diol I selected from potassium 2,5-dihydroxybenzenesulfonate, sodium N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonate, sodium 2-[tris(hydroxymethyl)methylamino]-1-ethanesulfonate, or sodium 3-[N-tris(hydroxymethyl)methylamino]-2-hydroxypropanesulfonate. and diol II in an amount such that the molar ratio of the number of carboxyl functional groups in dicarboxylic acid II to the number of hydroxy functional groups in diol II is 1.05 to 1.50, and a first-stage esterification reaction is carried out using benzenesulfonic acid in an amount of 10 to 100 ppm relative to the mass of the dicarboxylic acid as a catalyst at a temperature of 220 to 250°C, a pressure of 0.05 to 0.5 MPa, and a time of 3.0 to 5.0 hours, and further adding diol II in an amount 0.1 to 0.6 times the number of moles of dicarboxylic acid II used in the first stage, and carrying out a second-stage esterification reaction at a temperature of 240 to 260°C, a pressure of 0.1 to 0.5 MPa, and a time of 0.5 to 1.0 hours; an ionic polyester prepared by the above two-stage esterification reaction, a nonionic polyester prepared by another esterification reaction, and a polysiloxane modified at both ends with hydroxyl groups are mixed and polycondensed; a self-healing polymer which is a block copolymer having an ordered structure, which is composed of a nonionic polyester segment having 4 to 10 repeating units, an ionic polyester segment having 2 to 8 repeating units, and a polysiloxane segment having 2 to 10 repeating units, and in which all of the segments are connected by ester bonds; It is mixed with fiber-grade polyester and then processed in sequence through processes such as melt extrusion, cooling, solidification, oil application, and stretching to produce fibers. A method for producing polyester fibers that suppresses the generation of microplastics during use.

2. The fiber-grade polyester is any one of polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, and modified copolyester, and the modified copolyester has a polyester mass fraction of 80% or more and an intrinsic viscosity of 0.60 to 1.25 dl / g.

2. The method for producing polyester fibers that suppress the generation of microplastics during use according to claim 1.

3. The self-healing polymer has a total number of segments of 5 to 12, an intrinsic viscosity of 0.40 to 0.80 dl / g, and a half-crystallization time t １／２ It has the characteristics of 1.5 to 5.0 min and crystallization enthalpy of 20 to 40 J / g.

2. The method for producing polyester fibers that suppress the generation of microplastics during use according to claim 1.

4. A dicarboxylic acid I selected from terephthalic acid, isophthalic acid, and adipic acid, a diol I selected from ethylene glycol, propylene glycol, butanediol, and pentanediol, and a mixture of titanium glycolate, tetrabutyl titanate, and antimony. a catalyst in either antimony(III) acrylate, antimony(III) acetate or antimony(III) oxide; A nonionic polyester is prepared by adding a catalyst in an amount of 10 to 100 ppm based on the mass of dicarboxylic acid I at a molar ratio of dicarboxylic acid I to diol I of 1:1.05 to 1.50, and carrying out an esterification reaction at a temperature of 150 to 250°C, a pressure of 0.01 to 0.5 MPa, and a time of 1.5 to 3.5 hours.

2. The method for producing polyester fibers that suppress the generation of microplastics during use according to claim 1.

5. Based on the total mass of the nonionic polyester, ionic polyester, and polysiloxane, the amount of the ionic polyester added is 5 to 20%, and the amount of the polysiloxane added is 5 to 30%.

2. The method for producing polyester fibers that suppress the generation of microplastics during use according to claim 1.

6. The polycondensation is divided into a pre-condensation step at a temperature of 240 to 260°C, for 0.1 to 1.0 hours, and under a pressure of 500 to 1000 Pa, and a final condensation step at a temperature of 260 to 285°C, for 1.5 to 3.0 hours, and under a pressure of 0 to 100 Pa. Before the pre-condensation step, any one of tetrabutyl titanate, titanium glycolate, diantimony trioxide, antimony glycolate, and antimony (III) acetate is added as a catalyst in an amount of 50 to 500 ppm based on the total mass of the ionic polyester and the nonionic polyester.

2. The method for producing polyester fibers that suppress the generation of microplastics during use according to claim 1.

7. The method for producing polyester fibers that suppress the generation of microplastics during use according to claim 1, characterized in that the amount of self-healing polymer used is 1 to 10% by mass of the fiber-grade polyester.

8. The obtained fiber has the following properties: single yarn fineness of 1.5 to 5.0 dtex, reduction in oil-free intrinsic viscosity of 0.02 to 0.10 dl / g, breaking strength ≧ 4.5 cN / dtex, breaking elongation of 15 to 35%, static friction coefficient ≦ 0.20, dynamic friction coefficient ≦ 0.40, and self-repair speed of 0.1 to 1.0 μm / min, and the amount of fibrous microplastics generated during washing is reduced by 50 to 95% compared to products without the self-repairing polymer.

8. The method for producing polyester fibers that suppress the generation of microplastics during use according to claim 7.

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