Environment-friendly fluorine-free polyester fiber and preparation method thereof

Abstract

The application discloses an environment-friendly fluorine-free polyester fiber and a preparation method thereof, and belongs to the technical field of textiles. The problems of poor water repellency and poor air permeability in the prior art are solved. The environment-friendly fluorine-free polyester fiber comprises the following components: 69-73% of polyester chips, 5-6% of a first modifier polyhydroxy fatty acid ester, 9-10% of a second modifier polysiloxane-polyester block copolymer, 10% of a base material and 3-5% of a flexible auxiliary agent. The first modifier polyhydroxy fatty acid ester is prepared from polyhydroxy fatty acid ester. The fluorine-free modifier is introduced, the hydrophobic group is introduced through molecular structure design, efficient blocking of water and oil pollutants is realized, the fluorine-free modifier is fused with the polyester chips in the spinning stage through a melt blending-in-situ polymerization integrated process, the core-shell fiber structure is completed, the functional durability and air permeability are considered, the fluorine-free modifier is fused with the polyester chips in the melting stage, the auxiliary agent is avoided to be left on the surface of the fiber, more active sites are provided, and the whole does not contain perfluorinated compounds.

Description

Technical Field

[0001] This invention belongs to the field of textile technology, and more specifically, relates to an environmentally friendly fluorine-free polyester fiber and its preparation method. Background Technology

[0002] With the improvement of living standards, people have increasingly higher requirements for the quality of clothing fabrics. Besides basic requirements, people are increasingly favoring various comfort, appearance, and special properties in clothing textiles. To meet the needs of special applications, some new textiles that have undergone special finishing possess various excellent functions, one of which is water repellency. Polyester is one of the most widely used synthetic fibers at present. It has high geometric regularity, strong intermolecular forces, and weak reactivity, thus possessing excellent physicochemical properties. Functional finishing of polyester fabrics, such as waterproofing, flame retardancy, antistatic properties, antibacterial properties, and wrinkle resistance, can improve product grade and added value. Among these, water repellency finishing of polyester fabrics is a research hotspot, and its products are widely used in industrial textiles, vehicle interiors, and protective clothing.

[0003] Currently, water-repellent finishing of polyester fabrics mainly uses fluorocarbon reagents as raw materials and a pad-drying production method. While fluorocarbon reagents can impart waterproof, oil-repellent, and stain-resistant properties to fibers, they also have issues such as bioaccumulation and environmental persistence. Furthermore, because the polyethylene terephthalate (PET) polymer structure of polyester fabrics lacks reactive groups, the water-repellent polyester fabrics produced by this method have poor durability, making it difficult to meet the needs of large-scale applications. Therefore, how to achieve excellent water repellency in polyester fabrics without compromising their hand feel and breathability, and how to significantly improve environmental friendliness through fluorine-free finishing, thereby enhancing the overall quality of polyester fabrics, has become an urgent problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing an environmentally friendly, fluorine-free polyester fiber with excellent water repellency and breathability, as well as its preparation method.

[0005] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention for the environmentally friendly fluorine-free polyester fiber and its preparation method is as follows: An environmentally friendly, fluorine-free polyester fiber, by mass percentage, comprises the following components: 69-73% polyester chips, 5-6% of a first modifier (polyhydroxyalkanoate), 9-10% of a second modifier (polysiloxane-polyester block copolymer), 10% of a base material, and 3-5% of a flexibility aid. The first modifier, polyhydroxyalkanoate, is obtained from polyhydroxyalkanoate, and the structural formula of the polyhydroxyalkanoate is as follows: [OCHR1 (CH2)] x CO] Wherein, R1 is a straight-chain alkyl group, and X is 1, 2 or 3. When X is 1, the structural formula is 3-hydroxyalkanoate; when X is 2, the structural formula is 4-hydroxyalkanoate; and when X is 3, the structural formula is 5-hydroxyalkanoate.

[0006] A method for preparing an environmentally friendly, fluorine-free polyester fiber includes the following steps: S1 Screening of high-purity polyester chips: Select high-purity polyester chips with an intrinsic viscosity of 0.68~0.72dL / g for later use; S2 Preparation of fluorine-free modifier: Polyhydroxy fatty acid ester is added to dichloromethane and heated at 50-80℃ for 4-8 hours, solidified and dried to obtain the first modifier, polyhydroxy fatty acid ester. Hydroxypropyl-terminated polydimethylsiloxane oligomer, 2,6-bis(4-hydroxybenzyl)cyclohexanone, sebacate chloride and terephthaloyl chloride are synthesized by solution polymerization to obtain the second modifier, polysiloxane-polyester block copolymer. S3 Preparation of substrate: Add antioxidant 1010 and coupling agent KH-550 to polyester ether elastomer, and heat at 220-260℃ for 1.5-2 hours to obtain substrate; S4 Preparation of Fluorine-Free Polyester Fiber: Fluorine-free modifier and high-purity polyester chips are mixed by mass percentage and then added to a screw extruder for melt extrusion. The spinneret has irregularly shaped spinneret holes, the melt temperature is 280-300℃, and the melt flows out from the spinning assembly to obtain coarse polyester fiber. S5 modification: Coarse polyester fibers are immersed in a flexible auxiliary agent at 50-80℃ for 1-2 hours. After being taken out, they are stretched, heat-set and wound to obtain environmentally friendly fluorine-free polyester fibers.

[0007] In the above technical solution, a vacuum dryer is used to remove moisture from the surface of the polyhydroxyalkanoate in the raw material, preventing degradation of the material when it is directly heated to a high temperature before entering the screw extruder. This not only reduces the probability of degradation and performance loss during the drying process, but also meets the water content requirements for spinning. If the water content is too high during spinning, hydrolysis will occur in the high-temperature screw extruder, forming bubbles, leading to filament breakage and unstable spinning. A fluorine-free modifier is selected to introduce hydrophobic side chains, which are fixed by oiling during spinning and stretching and setting of the polyester chips, achieving good hydrophobicity of the fiber. This solves the problem of the great harm to human health and the environment caused by the current use of fluorinated oils. By adding additives, the time required to achieve non-sticking of polyhydroxyalkanoate is further reduced, thereby improving processing efficiency. At the same time, the fiber breaking elongation reaches more than 35%, improving the softness of the hand and solving the problem of stiffness of fluorine-free fibers.

[0008] Preferably, the polyhydroxy fatty acid ester in step S2 includes one or more of poly-3-hydroxybutyrate-4-hydroxybutyrate and poly-3-hydroxybutyrate.

[0009] Preferably, the preparation of the copolyester elastomer in step S3 includes the following steps: (1) mixing terephthalic acid and butanediol in a molar ratio of 1:1.1 to 1:1.8, and then adding a butanediol solution with a titanium catalyst to prepare a slurry; (2) injecting the slurry into an esterification reactor and esterifying it at 190 to 240°C for 1.5 to 2 hours to obtain the intermediate dihydroxybutyl terephthalate; (3) preparing a polyether butanediol solution and feeding it into a mixer by a metering pump. After being mixed with the intermediate dihydroxybutyl terephthalate, it is injected into the prepolymerization reactor; (4) the esterification reactant enters the prepolymerization reactor and undergoes polycondensation reaction at an absolute pressure of 2-5 kPa and a temperature of 190-240°C for 30-80 min; (5) the prepolymer is introduced into the final polycondensation reactor and undergoes polycondensation reaction at an absolute pressure of 0.2-2 kPa and a temperature of 220-260°C for 80-200 min to obtain the copolyester elastomer.

[0010] Preferably, the flexible additive in step S5 includes a dispersant, an antistatic agent, and a nucleating agent, with the dispersant, antistatic agent, and nucleating agent added in a mass fraction ratio of 0.5%, 0.4%, and 0.3%, respectively. This avoids agglomeration of the modifier and degradation of the substrate during the melting process, ensuring uniform and stable product performance.

[0011] Preferably, the dispersant is EBS and the antistatic agent is glyceryl monostearate.

[0012] Preferably, the nucleating agent includes one or more of talc, calcium carbonate, titanium dioxide, and zirconium hydrogen phosphate.

[0013] Compared with the prior art, the beneficial effects of the present invention are: This invention introduces a fluorine-free modifier and incorporates hydrophobic groups through molecular structure design to achieve highly efficient barrier properties against water and oil contaminants, resulting in a stain resistance rate of over 90% and a biodegradability rate of over 60%. It employs an integrated melt blending-in-situ polymerization process to fuse the fluorine-free modifier with polyester chips during the spinning stage, optimizing spinning temperature and process to achieve a core-shell fiber structure that balances functional durability and breathability, with a breathability of up to 180 L / m³. 2 •s; The fluorine-free modifier is fused with polyester chips during the melting stage, avoiding residual additives on the fiber surface and providing more active sites for subsequent finishing. The whole product is free of perfluorinated compounds, which is conducive to green and sustainable development. Detailed Implementation

[0014] The invention will be further described below with reference to specific embodiments: This invention provides an environmentally friendly, fluorine-free polyester fiber, comprising the following components by mass percentage: 69-73% polyester chips, 5-6% of a first modifier (polyhydroxyalkanoate), 9-10% of a second modifier (polysiloxane-polyester block copolymer), 10% of a base material, and 3-5% of a flexibility aid. The first modifier, polyhydroxyalkanoate, is obtained from polyhydroxyalkanoate, and the structural formula of the polyhydroxyalkanoate is as follows: [OCHR1 (CH2)] x CO] Wherein, R1 is a straight-chain alkyl group, and X is 1, 2 or 3. When X is 1, the structural formula is 3-hydroxyalkanoate; when X is 2, the structural formula is 4-hydroxyalkanoate; and when X is 3, the structural formula is 5-hydroxyalkanoate.

[0015] Example 1

[0016] A method for preparing an environmentally friendly, fluorine-free polyester fiber includes the following steps: S1 Screening of high-purity polyester chips: Select high-purity polyester chips with an intrinsic viscosity of 0.68~0.72dL / g for later use; S2 Preparation of fluorine-free modifier: Poly-3-hydroxybutyrate-4-hydroxybutyrate was added to dichloromethane, heated at 50°C for 4 hours, solidified, and dried to obtain the first modifier, polyhydroxy fatty acid ester. Hydroxypropyl-terminated polydimethylsiloxane oligomer, 2,6-bis(4-hydroxybenzyl)cyclohexanone, sebacate chloride, and terephthaloyl chloride were synthesized by solution polymerization to obtain the second modifier, polysiloxane-polyester block copolymer. The preparation of copolyester elastomer includes the following steps: (1) terephthalic acid and butanediol are mixed in a molar ratio of 1:1.1 to 1:1.8 and then a butanediol solution with a titanium catalyst is added to prepare a slurry; (2) the slurry is injected into an esterification reactor and esterified at 190 to 240°C for 1.5 to 2 hours to obtain the intermediate dihydroxybutyl terephthalate; (3) a polyether butanediol solution is prepared, which is fed into a mixer by a metering pump and mixed with the intermediate dihydroxybutyl terephthalate, and then injected into a prepolymerization reactor; (4) the esterification reactant enters the prepolymerization reactor and undergoes a polycondensation reaction at an absolute pressure of 2 to 5 kPa and a temperature of 190 to 240°C for 30 to 80 minutes; (5) the prepolymer enters the final polycondensation reactor and undergoes polycondensation at an absolute pressure of 0.2 to 2 kPa and a temperature of 220 to 260°C for 80 to 200 minutes to obtain the copolyester elastomer; S3 Preparation of substrate: Add antioxidant 1010 and coupling agent KH-550 to polyester ether elastomer, heat at 220℃ for 1.5h to obtain substrate; S4 Preparation of Fluorine-Free Polyester Fiber: Fluorine-free modifier and high-purity polyester chips are mixed by mass percentage and then added to a screw extruder for melt extrusion. The spinneret has irregularly shaped spinneret holes, the melt temperature is 280-300℃, and the melt flows out from the spinning assembly to obtain coarse polyester fiber. S5 Modification: Coarse polyester fibers are immersed in a flexible auxiliary agent at 50°C for 1 hour. After being taken out, they are stretched, heat-set, and wound to obtain environmentally friendly fluorine-free polyester fibers. The flexible auxiliary agent includes a dispersant, an antistatic agent, and a nucleating agent. The mass fractions of the dispersant EBS, the antistatic agent glyceryl monostearate, and the nucleating agent talc are 0.5%, 0.4%, and 0.3%, respectively.

[0017] Example 2

[0018] A method for preparing an environmentally friendly, fluorine-free polyester fiber includes the following steps: S1 Screening of high-purity polyester chips: Select high-purity polyester chips with an intrinsic viscosity of 0.68~0.72dL / g for later use; S2 Preparation of fluorine-free modifier: Poly-3-hydroxybutyrate was added to dichloromethane and heated at 50°C for 4 hours. After solidification and drying, the first modifier, polyhydroxy fatty acid ester, was obtained. Hydroxypropyl-terminated polydimethylsiloxane oligomer, 2,6-bis(4-hydroxybenzyl)cyclohexanone, sebacate chloride, and terephthaloyl chloride were synthesized by solution polymerization to obtain the second modifier, polysiloxane-polyester block copolymer. The preparation of copolyester elastomer includes the following steps: (1) terephthalic acid and butanediol are mixed in a molar ratio of 1:1.1 to 1:1.8 and then a butanediol solution with a titanium catalyst is added to prepare a slurry; (2) the slurry is injected into an esterification reactor and esterified at 190 to 240°C for 1.5 to 2 hours to obtain the intermediate dihydroxybutyl terephthalate; (3) a polyether butanediol solution is prepared, which is fed into a mixer by a metering pump and mixed with the intermediate dihydroxybutyl terephthalate, and then injected into a prepolymerization reactor; (4) the esterification reactant enters the prepolymerization reactor and undergoes a polycondensation reaction at an absolute pressure of 2 to 5 kPa and a temperature of 190 to 240°C for 30 to 80 minutes; (5) the prepolymer enters the final polycondensation reactor and undergoes polycondensation at an absolute pressure of 0.2 to 2 kPa and a temperature of 220 to 260°C for 80 to 200 minutes to obtain the copolyester elastomer; S3 Preparation of substrate: Add antioxidant 1010 and coupling agent KH-550 to polyester ether elastomer, and heat at 220℃ for 1.5 to 2 hours to obtain the substrate; S4 Preparation of Fluorine-Free Polyester Fiber: Fluorine-free modifier and high-purity polyester chips are mixed by mass percentage and then added to a screw extruder for melt extrusion. The spinneret has irregularly shaped spinneret holes, the melt temperature is 280-300℃, and the melt flows out from the spinning assembly to obtain coarse polyester fiber. S5 Modification: Coarse polyester fibers are immersed in a flexible auxiliary agent at 50°C for 1 hour. After being taken out, they are stretched, heat-set, and wound to obtain environmentally friendly fluorine-free polyester fibers. The flexible auxiliary agent includes a dispersant, an antistatic agent, and a nucleating agent. The mass fractions of the dispersant EBS, the antistatic agent glyceryl monostearate, and the nucleating agent calcium carbonate are 0.5%, 0.4%, and 0.3%, respectively.

[0019] Example 3

[0020] A method for preparing an environmentally friendly, fluorine-free polyester fiber includes the following steps: S1 Screening of high-purity polyester chips: Select high-purity polyester chips with an intrinsic viscosity of 0.68~0.72dL / g for later use; S2 Preparation of fluorine-free modifier: Poly-3-hydroxybutyrate-4-hydroxybutyrate was added to dichloromethane, heated at 80°C for 8 hours, solidified, and dried to obtain the first modifier, polyhydroxy fatty acid ester. Hydroxypropyl-terminated polydimethylsiloxane oligomer, 2,6-bis(4-hydroxybenzyl)cyclohexanone, sebacate chloride, and terephthaloyl chloride were synthesized by solution polymerization to obtain the second modifier, polysiloxane-polyester block copolymer. The preparation of copolyester elastomer includes the following steps: (1) terephthalic acid and butanediol are mixed in a molar ratio of 1:1.1 to 1:1.8 and then a butanediol solution with a titanium catalyst is added to prepare a slurry; (2) the slurry is injected into an esterification reactor and esterified at 190 to 240°C for 1.5 to 2 hours to obtain the intermediate dihydroxybutyl terephthalate; (3) a polyether butanediol solution is prepared, which is fed into a mixer by a metering pump and mixed with the intermediate dihydroxybutyl terephthalate, and then injected into a prepolymerization reactor; (4) the esterification reactant enters the prepolymerization reactor and undergoes a polycondensation reaction at an absolute pressure of 2 to 5 kPa and a temperature of 190 to 240°C for 30 to 80 minutes; (5) the prepolymer enters the final polycondensation reactor and undergoes polycondensation at an absolute pressure of 0.2 to 2 kPa and a temperature of 220 to 260°C for 80 to 200 minutes to obtain the copolyester elastomer; S3 Preparation of substrate: Add antioxidant 1010 and coupling agent KH-550 to polyester ether elastomer, heat at 260℃ for 2 hours to obtain substrate; S4 Preparation of Fluorine-Free Polyester Fiber: Fluorine-free modifier and high-purity polyester chips are mixed by mass percentage and then added to a screw extruder for melt extrusion. The spinneret has irregularly shaped spinneret holes, the melt temperature is 280-300℃, and the melt flows out from the spinning assembly to obtain coarse polyester fiber. S5 Modification: Coarse polyester fibers are immersed in a flexible auxiliary agent at 80°C for 2 hours. After being taken out, they are stretched, heat-set, and wound to obtain environmentally friendly fluorine-free polyester fibers. The flexible auxiliary agent includes a dispersant, an antistatic agent, and a nucleating agent. The mass fractions of the dispersant EBS, the antistatic agent glyceryl monostearate, and the nucleating agent talc are 0.5%, 0.4%, and 0.3%, respectively.

[0021] Comparative Example 1 No fluorine-free modifier was added; otherwise, refer to Example 1.

[0022] The environmentally friendly fluorine-free polyester fibers prepared in Examples 1-3 and Comparative Example 1 were subjected to performance testing. (1) Wash resistance test The test was conducted in accordance with GB / T4745-2012 "Test and Evaluation of Water Repellency of Textiles - Water-Soaking Method". The test was performed with 100 washes of water at a temperature of 20°C using distilled water. The test was repeated three times, and the average value was calculated. The average value was rounded to the nearest integer or half-level and rated according to 1-5. The data are shown in Table 1. Based on the above experimental data, it can be seen that the environmentally friendly fluorine-free polyester fibers prepared in Examples 1-3 have a high waterproof performance rating, high wash fastness, and excellent waterproof performance after 20-100 washes. The fibers obtained in Comparative Example 1 have a low waterproof performance rating, low wash fastness, and poor waterproof performance after 20-100 washes. By adding a fluorine-free modifier during the melting stage to remove residual additives in the fiber, more active sites are provided for subsequent waterproofing performance. Furthermore, the modified fiber acts as a molecular bridge, eliminating the need for special fluorine-free waterproofing agents and producing fluorine-free waterproof fibers with excellent wash resistance and waterproofing properties.

[0023] In summary, these are merely preferred embodiments of the present invention and are not intended to limit the scope of the invention. All equivalent variations and modifications made in accordance with the shape, structure, features, and spirit of the claims of the present invention should be included within the scope of the claims of the present invention.

Claims

1. An environmentally friendly, fluorine-free polyester fiber, characterized in that, By mass percentage, it comprises the following components: 69-73% polyester chips, 5-6% of the first modifier polyhydroxy fatty acid ester, 9-10% of the second modifier polysiloxane-polyester block copolymer, 10% substrate, and 3-5% flexibility aid. The first modifier polyhydroxy fatty acid ester is obtained from polyhydroxy fatty acid ester, and the structural formula of the polyhydroxy fatty acid ester is as follows: [PROTECTION1 (CH2)] x WHAT] Wherein, R1 is a straight-chain alkyl group, and X is 1, 2 or 3. When X is 1, the structural formula is 3-hydroxyalkanoate; when X is 2, the structural formula is 4-hydroxyalkanoate; and when X is 3, the structural formula is 5-hydroxyalkanoate.

2. A method for preparing environmentally friendly fluorine-free polyester fiber, characterized in that, Includes the following steps: S1 Screening of high-purity polyester chips: Select high-purity polyester chips with an intrinsic viscosity of 0.68~0.72dL / g for later use; S2 Preparation of fluorine-free modifier: Polyhydroxy fatty acid ester is added to dichloromethane and heated at 50-80℃ for 4-8 hours, solidified and dried to obtain the first modifier, polyhydroxy fatty acid ester. Hydroxypropyl-terminated polydimethylsiloxane oligomer, 2,6-bis(4-hydroxybenzyl)cyclohexanone, sebacate chloride and terephthaloyl chloride are synthesized by solution polymerization to obtain the second modifier, polysiloxane-polyester block copolymer. S3 Preparation of substrate: Add antioxidant 1010 and coupling agent KH-550 to polyester ether elastomer, and heat at 220-260℃ for 1.5-2 hours to obtain substrate; S4 Preparation of Fluorine-Free Polyester Fiber: Fluorine-free modifier and high-purity polyester chips are mixed by mass percentage and then added to a screw extruder for melt extrusion. The spinneret has irregularly shaped spinneret holes, the melt temperature is 280-300℃, and the melt flows out from the spinning assembly to obtain coarse polyester fiber. S5 modification: Coarse polyester fibers are immersed in a flexible auxiliary agent at 50-80℃ for 1-2 hours. After being taken out, they are stretched, heat-set and wound to obtain environmentally friendly fluorine-free polyester fibers.

3. The method for preparing environmentally friendly fluorine-free polyester fiber according to claim 1, characterized in that: The polyhydroxy fatty acid ester in step S2 includes one or more of poly-3-hydroxybutyrate, 4-hydroxybutyrate, and poly-3-hydroxybutyrate.

4. The method for preparing environmentally friendly fluorine-free polyester fiber according to claim 1, characterized in that: The preparation of the copolyester elastomer in step S3 includes the following steps: (1) mixing terephthalic acid and butanediol in a molar ratio of 1:1.1 to 1:1.8, and then adding a butanediol solution with a titanium catalyst to prepare a slurry; (2) injecting the slurry into an esterification reactor and esterifying it at 190 to 240°C for 1.5 to 2 hours to obtain the intermediate dihydroxybutyl terephthalate; (3) preparing a polyether butanediol solution, which is then pumped into a mixer by a metering pump and mixed with... After mixing the intermediate dihydroxybutyl terephthalate, it is injected into the prepolymerization reactor; (4) the esterification reactant enters the prepolymerization reactor and undergoes polycondensation reaction at an absolute pressure of 2-5 kPa and a temperature of 190-240°C for 30-80 min; (5) the prepolymer is introduced into the final polycondensation reactor and undergoes polycondensation reaction at an absolute pressure of 0.2-2 kPa and a temperature of 220-260°C for 80-200 min to obtain the copolyester elastomer.

5. The method for preparing environmentally friendly fluorine-free polyester fiber according to claim 1, characterized in that: The flexible additives in step S5 include dispersants, antistatic agents, and nucleating agents, and the addition amounts of dispersants, antistatic agents, and nucleating agents are 0.5%, 0.4%, and 0.3% by mass fraction, respectively. To avoid the agglomeration of modifiers and degradation of the substrate during the melting process, and to ensure uniform and stable product performance.

6. The method for preparing environmentally friendly fluorine-free polyester fiber according to claim 5, characterized in that: The dispersant is EBS and the antistatic agent is glyceryl monostearate.

7. The method for preparing environmentally friendly fluorine-free polyester fiber according to claim 5, characterized in that: The nucleating agent includes one or more of talc, calcium carbonate, titanium dioxide, and zirconium hydrogen phosphate.

Images