High-elasticity recycled polyester material for chemical fibers and preparation method thereof

Abstract

The invention discloses a high-elasticity regenerated polyester material for chemical fibers and a preparation method thereof, and relates to the technical field of high polymer material regeneration. The invention discloses a high-elasticity regenerated polyester material for chemical fibers. The composite material is prepared from the following raw materials in parts by weight: 8 to 12 parts of glass fiber, 0.2 to 0.4 part of silane coupling agent KH-550, 4 to 6 parts of absolute ethyl alcohol, 4 to 6 parts of aluminum hypophosphite, 2 to 4 parts of melamine cyanurate, 0.05 to 0.15 part of aryl sodium phosphate, 65 to 75 parts of modified regenerated polyester, 20 to 30 parts of modified bio-based elastomer, 5 to 10 parts of maleic anhydride grafted polyolefin elastomer, 0.3 to 0.8 part of antioxidant and 1 to 2 parts of carbon black master batch. 0.1 to 0.3 part of a silicone lubricant; and 5 to 10 parts of didodecyl dimethyl ammonium chloride. Through supercritical chain extension, nano grafting and gradient crystallization technologies, the mechanical property and elasticity of the regenerated polyester are improved. The modified bio-based elastomer, the flame retardant and the antistatic agent have a synergistic effect, so that the material has high elasticity, flame retardance and antistatic functions. The method is suitable for high-end application in the field of chemical fibers, realizes high-value recycling of waste polyester, and has remarkable environmental protection benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer material regeneration, in particular to a high-elasticity regenerated polyester material for chemical fiber and a preparation method thereof. Background Art

[0002] In the field of polymer material recycling technology, polyester (PET), the world's largest synthetic fiber raw material, generates a massive amount of waste annually due to its use in textiles, packaging, and other fields. According to statistics, over 50 million tons of discarded PET bottle flakes and chemical fiber waste are generated globally each year. While traditional physical recycling methods can achieve reuse, they suffer from severe molecular chain degradation, deterioration of mechanical properties, and insufficient elastic recovery. Consequently, the recycled materials can only be used in low-end products such as nonwovens or fillings, creating a dilemma of "downgrading high-quality resources."

[0003] From a technical perspective, existing recycled polyester modification faces multiple challenges: First, conventional melt polycondensation chain extension technology has the defects of low reaction efficiency and wide molecular weight distribution, making it difficult to effectively restore the molecular chain length; second, the traditional blending method of adding elastomers has poor interfacial compatibility and easily forms a phase separation structure, resulting in the inability to balance the elasticity and rigidity of the material; third, the lack of functionality is prominent - the limiting oxygen index of ordinary recycled polyester is only about 21%, and its flammability limits its application in electronics, automotive interiors and other fields, and its surface resistivity is as high as 10 12 Ω or above, static electricity accumulation can easily lead to safety hazards such as dust explosions.

[0004] Furthermore, while the introduction of bio-based elastomers offers new avenues for modification, unmodified bio-based materials suffer from issues such as insufficient thermal stability and difficulty controlling crosslinking. Existing flame retardant systems, such as halogenated flame retardants, are increasingly restricted due to environmental concerns. Halogen-free flame retardants, such as aluminum hypophosphite, also suffer from the problem of hardening and brittleness due to high addition levels. Achieving the high strength, high elasticity, and multifunctional integration of recycled polyester through multi-scale structural design has become a pressing technical bottleneck for the industry. Summary of the Invention

[0005] In response to the deficiencies in the prior art, the present invention provides a highly elastic recycled polyester material for chemical fiber and a preparation method thereof, which solves the problems of severe molecular chain degradation, deterioration of mechanical properties, and insufficient elastic recovery rate of traditional materials.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] A high-elasticity recycled polyester material for chemical fibers comprises the following raw materials in parts by weight: 8-12 parts of glass fibers, 0.2-0.4 parts of a silane coupling agent KH-550, 4-6 parts of anhydrous ethanol, 4-6 parts of aluminum hypophosphite, 2-4 parts of melamine cyanurate, 0.05-0.15 parts of sodium aryl phosphate, 65-75 parts of modified recycled polyester, 20-30 parts of a modified bio-based elastomer, 5-10 parts of maleic anhydride grafted polyolefin elastomer (POE-g-MAH), 0.3-0.8 parts of an antioxidant, 1-2 parts of a carbon black masterbatch, 0.1-0.3 parts of a silicone lubricant, and 5-10 parts of didodecyldimethylammonium chloride.

[0008] Furthermore, the glass fiber has a diameter of 5-8 μm; the grafting rate of the maleic anhydride grafted polyolefin elastomer is 1.0-1.5%, and the melt index at 190° C. and 2.16 kg is 3-8 g / 10 min; and the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0009] Furthermore, the modified recycled polyester is specifically prepared in the following steps:

[0010] A1. Place recycled polyester fragments crushed to 2 mm in an autoclave, evacuate to -0.1 MPa, inject liquid carbon dioxide to a pressure of 12 MPa, raise the temperature to 115°C, and evenly inject an epoxy chain extender using an atomizing spray gun. Maintain constant temperature and pressure while stirring at 150 rpm for 45 minutes to allow the chain extender to penetrate the fragments. After the reaction is completed, slowly reduce the pressure to normal pressure. After the temperature drops to room temperature, remove the modified recycled polyester fragments.

[0011] A2: Fumed silica with a particle size of 50 nm was placed in a radio frequency plasma furnace and treated with an argon / ethylene mixture at 300 W for 15 minutes to form surface active sites. The plasma-activated nano-silica and A1-modified recycled polyester fragments were simultaneously added to a fluidized bed reactor, sprayed with ε-caprolactone monomer, and reacted at 120°C for 2 hours under a nitrogen atmosphere to produce polycaprolactone-grafted silica composite particles.

[0012] A3. Add product A2, an aromatic phosphate nucleating agent, and an organic carboxylate nucleating aid into a high-speed mixer and dry-mix at 80°C and 2000 rpm for 10 min. The uniformly mixed material is sent into a gradient cooling crystallizer, cooled to 195°C and maintained at this temperature for 90 seconds to form a spherulite structure with an average diameter of 380 nm.

[0013] Furthermore, the mass ratio of the recycled polyester fragments to the epoxy chain extender in A1 is 100:0.6; the epoxy chain extender is a styrene-acrylate copolymer with an epoxy value of 0.45 mol / 100 g.

[0014] Furthermore, the volume ratio of argon and ethylene in A2 is 95:5, and the mass ratio of silica, A1 modified recycled polyester fragments, and ε-caprolactone monomer is 1:125:3; plasma activation enables the thickness of the grafted layer to be precisely controlled to 65±5 nm.

[0015] Furthermore, the mass ratio of the A2 product, the aromatic phosphate nucleating agent, and the organic carboxylate nucleating aid in A3 is 100:0.3:0.1; the aromatic phosphate nucleating agent is sodium bis(4-tert-butylphenyl) phosphate, and the organic carboxylate nucleating aid is a compound of sodium benzoate and sodium stearate in a mass ratio of 3:2.

[0016] Furthermore, the modified recycled polyester uses a composite nucleating agent to induce nano-crystallization and adopts gradient cooling crystallization control. In the first stage, 280°C→230°C, the cooling rate is 20°C / s, and in the second stage, 230°C→195°C, the cooling rate is 5°C / s; the modified recycled polyester constructs a core-shell-crystal triple structure through supercritical chain extension + nano-grafting.

[0017] Furthermore, the modified bio-based polyetherester elastomer is specifically prepared in the following steps:

[0018] B1. Bio-based polyether ester elastomer particles and di-tert-butyl peroxide were mixed at 180°C and 50 rpm for 90 seconds. After mixing, the mixture was immediately cooled to 60°C with cold water. The crosslinking degree was controlled by solvent extraction to obtain a pre-crosslinked elastomer.

[0019] B2. The pre-crosslinked elastomer obtained in B1 and ethylene furandicarboxylate monomer were added to a reactor, the reactor was evacuated to -0.095 MPa, the temperature was raised to 245°C, tetrabutyl titanate was added, and a melt reaction was carried out at 100 rpm for 40 minutes to form 8-15 nm rigid microdomains. After the reaction was completed, the reactor was cooled to room temperature, the copolymer was taken out, dissolved in acetone, poured into methanol for precipitation, and the product was filtered and dried in a vacuum drying oven at 60°C for 12 hours;

[0020] B3. Mix the block copolymer obtained in B2 with zinc acrylate on a two-roll mill, control the roll temperature at 170°C, and pass the mill 10 times at 15 rpm to evenly disperse the metal ions in the block copolymer. Transfer the milled material to a hot press at 180°C and maintain the pressure for 10 minutes to form an ion cross-linking network between the metal ions and the block copolymer. After the hot pressing is completed, remove the sample and cool it naturally at room temperature to obtain the final modified bio-based polyether ester elastomer material.

[0021] Furthermore, the mass ratio of the bio-based polyether ester elastomer particles and di-tert-butyl peroxide in B1 is 100:0.8; the bio-based polyether ester elastomer is a block copolymer containing a polyether soft segment and an aromatic polyester hard segment, with a bio-based content ≥30%, a melt index of 4-10g / 10min at 190°C and 2.16kg, and a Shore D hardness of 35-45; B1 is modified by a solvent extraction method, the pre-crosslinked elastomer particles are placed in a Soxhlet extractor, toluene is used as the extractant, and the extraction is carried out for 24 hours to remove the uncrosslinked part and control the crosslinking degree at 35±3%.

[0022] Furthermore, the mass ratio of the pre-crosslinked elastomer, ethylene glycol furandicarboxylate monomer, and tetrabutyl titanate in B2 is 100:12:0.05.

[0023] Furthermore, the mass ratio of the block copolymer to zinc acrylate in the B3 is 100:2.5; and the ionic crosslinking point density is 3.2×10 20 / cm 3 .

[0024] Furthermore, the modified bio-based polyetherester elastomer avoids excessive cross-linking through time-temperature coordinated control.

[0025] A method for preparing a highly elastic recycled polyester material for chemical fiber, comprising the following steps:

[0026] S1. Place glass fiber in a high-speed mixer, spray a mixture of silane coupling agent KH-550 and anhydrous ethanol, stir at 85°C and 1200 rpm for 15 minutes, and then dry at 105°C to obtain activated glass fiber; add aluminum hypophosphite and melamine cyanurate to a ball mill, and ball mill at 400 rpm for 60 minutes under nitrogen protection to adjust D50 to ≤ 2.5 μm to obtain a flame retardant compound powder; mix sodium aryl phosphate with anhydrous ethanol, and ultrasonically disperse at 200 W power for 10 minutes to obtain a β-crystal nucleating agent-ethanol dispersion;

[0027] S2. Set the internal mixer to 240°C, add modified recycled polyester, modified bio-based elastomer, and maleic anhydride grafted polyolefin elastomer, and mix at 60 rpm for 8 minutes. Then add antioxidant and carbon black masterbatch and continue mixing for 3 minutes. Cool the internal mixer to 210°C, add flame retardant compound powder, increase the rotor speed to 90 rpm and mix for 5 minutes, and then add activated glass fiber three times, each time with an interval of 90 seconds. The melt is discharged from the internal mixer and passed into a supercritical device, and dynamically mixed at 8-12 MPa and 120°C for 5 minutes to form a 0.3 μm interpenetrating grid.

[0028] S3, open the twin-screw extruder, set the temperature of each zone: 200 ℃ in zone I, 210 ℃ in zone II, 220 ℃ in zone III, 230 ℃ in zone IV, 245 ℃ in zone V, and 260 ℃ in zone VI. After each temperature zone reaches the set temperature, keep warm for 30 min; the screw speed is 320 rpm, the melt after supercritical treatment is added to the main feeding port of zone I, and the β crystal nucleating agent-ethanol dispersion is injected at a spray rate of 0.5 L / min in the side feeding port of zone III. The vacuum degree in zone IV is adjusted to -0.08 MPa, and silicone lubricant is injected into the melt pump of zone V. 800 rpm high shear mixing is carried out for 3 min, and the melt is extruded through a hanger die with an aperture of 3 mm, passed into a 25 ℃ water tank for cooling, 12 m / min traction, pelletized into 4 mm length particles, centrifuged and dehydrated for 5 min at 1200 rpm, and then dried with hot air at 80 ℃ for 30 min;

[0029] S4. Place the dried particles into the furnace chamber, introduce nitrogen at a flow rate of 5 L / min, raise the temperature to 195°C at 15°C / min and hold the temperature constant for 30 min, then lower the temperature to 145°C at 5°C / min and hold the temperature constant for 45 min, and finally lower the temperature to 60°C at 2°C / min, turn off the heating, and allow the mixture to cool naturally to room temperature;

[0030] S5. Add 0.5-1.0 wt% didodecyldimethylammonium chloride to deionized water, stir and dissolve at 40°C for 20 minutes, and then filter through a 100-mesh sieve to prepare a coating liquid. The particles remain in the coating liquid at 60°C for 20 seconds, and are dried with hot air at 100°C for 5 minutes to form an antistatic layer of 70-90 nm. Randomly sample and test qualified products with a surface resistance of ≤109Ω and seal and package them.

[0031] Furthermore, the S4 is a gradient crystallization operation, wherein the first stage is nucleation, and nitrogen gas is introduced at a flow rate of 5 L / min to prevent oxidation and yellowing; the second stage is crystal growth, and the resulting spherulite size is 250±30 nm.

[0032] The present invention provides a high elasticity recycled polyester material for chemical fiber and a preparation method thereof, which has the following characteristics:

[0033] Beneficial effects:

[0034] 1. Microstructure innovation improves material performance: By constructing a core-shell-crystal triple advanced structure, a performance breakthrough is achieved at the molecular level. Supercritical chain extension technology uses the permeability of liquid carbon dioxide to promote the uniform diffusion of epoxy chain extenders into the interior of recycled polyester fragments, effectively restoring the length of degraded molecular chains and reshaping the material's skeleton strength. The nanografting process uses radio frequency plasma to activate the silica surface, forming composite particles with a strong interface bond with the polycaprolactone monomer, like "nano rivets" to enhance the interfacial force. Gradient crystallization control uses a staged cooling process to induce the material to form a uniformly sized spherulite structure, avoiding defects in the traditional crystallization process. Under the synergistic effect of the triple structure, a 0.3μm-level interpenetrating network is formed inside the material, which not only combines high strength and high elasticity, but also gives it excellent elastic recovery ability, solving the problem of traditional recycled polyester being "hard and brittle".

[0035] 2. Synergistic Effects of Environmentally Friendly Raw Materials and Functional Additives: Using industrial waste materials such as discarded polyester bottle flakes as the base raw material, combined with polyetherester elastomers with over 30% bio-based content, this system introduces renewable resources into the polymer material system, reducing dependence on petroleum-based raw materials from the source. The halogen-free flame retardant system utilizes a combination of aluminum hypophosphite and melamine cyanurate. This system enhances the material's fire resistance through both vapor-phase and condensed-phase flame retardancy, avoiding the toxic smoke release associated with halogen-based flame retardants. The nano-antistatic coating formed by didodecyldimethylammonium chloride synergizes with the conductive network within the material to achieve stable control of surface resistance. This raw material combination strategy not only maximizes the value of waste resources but, through the coordinated design of functional additives, enables the material to simultaneously possess multiple functions, such as flame retardancy and antistatic properties, breaking through the limitations of the single functionality of traditional recycled materials.

[0036] 3. Multi-scale preparation technology breaks through performance bottlenecks: Innovative integration of cross-scale processes such as supercritical chain extension, nanografting, and gradient crystallization. Under a supercritical fluid environment, the efficiency of the chain extension reaction is significantly improved, effectively addressing the wide molecular weight distribution. Radio frequency plasma activation technology precisely controls the thickness of the nano-silica grafted layer, enhancing interfacial bonding strength and resolving the challenge of poor compatibility between the elastomer and the matrix in traditional blending processes. The gradient cooling crystallization process, through staged temperature control, increases the material's crystallinity and significantly raises its heat distortion temperature. These multiple technologies synergistically overcome multiple bottlenecks, such as recycled polyester molecular chain degradation, poor interfacial compatibility, and imperfect crystallization, driving a qualitative leap in the material's overall performance.

[0037] 4. Expansion of High-End Application Scenarios and Industrial Value Upgrading: The material's multifunctional integration of high elasticity, flame retardancy, and antistatic properties meets the stringent requirements of high-end chemical fiber applications, such as internal cables for electronic devices and automotive interior fabrics, successfully replacing traditional petroleum-based polyester materials. At the industrial level, technological innovation in the recycling of waste polyester has increased the added value per ton of raw material by 30%, forming a closed-loop industrial chain of "waste recycling - modification and upgrading - high-end application." This environmental benefit of an annual carbon reduction of 150,000 tons not only supports the goal of carbon neutrality but also establishes a model for "resource recycling - performance optimization - green manufacturing" in the recycled materials industry, driving the polymer materials industry towards low-carbon, high-value production. DETAILED DESCRIPTION

[0038] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0039] Example 1: Preparation of high-elasticity recycled polyester material for chemical fiber. The specific preparation steps are as follows:

[0040] S1. Place 8 parts of glass fiber in a high-speed mixer, spray 0.2 parts of a silane coupling agent KH-550 and 4 parts of anhydrous ethanol mixture, stir at 85°C and 1200 rpm for 15 minutes, and then dry at 105°C to obtain activated glass fiber; add 4 parts of aluminum hypophosphite and 2 parts of melamine cyanurate to a ball mill, and under nitrogen protection, ball mill at 400 rpm for 60 minutes to make D50 ≤ 2.5 μm to obtain a flame retardant compound powder; mix 0.05 parts of sodium aryl phosphate with 1 part of anhydrous ethanol, and ultrasonically disperse at 200 W power for 10 minutes to obtain a β crystal nucleating agent-ethanol dispersion;

[0041] S2. Set the internal mixer to 240°C, add 65 parts of modified recycled polyester, 20 parts of modified bio-based elastomer, and 5 parts of POE-g-MAH, mix at 60 rpm for 8 minutes, then add 0.3 parts of antioxidant and 1 part of carbon black masterbatch and continue mixing for 3 minutes; cool the internal mixer to 210°C, add 6 parts of flame retardant compound powder, increase the rotor speed to 90 rpm and mix for 5 minutes, then add 8 parts of activated glass fiber in three times, each time with an interval of 90 seconds; the melt is discharged from the internal mixer and passed into a supercritical device, and dynamically mixed at 8 MPa and 120°C for 5 minutes to form a 0.3 μm interpenetrating grid;

[0042] S3, open the twin-screw extruder, set the temperature of each zone: 200 ℃ in zone Ⅰ, 210 ℃ in zone Ⅱ, 220 ℃ in zone Ⅲ, 230 ℃ in zone Ⅳ, 245 ℃ in zone Ⅴ, and 260 ℃ in zone Ⅵ. After each temperature zone reaches the set temperature, keep warm for 30 min; the screw speed is 320 rpm, the melt after supercritical treatment is added to the main feeding port of zone Ⅰ, and the β crystal nucleating agent-ethanol dispersion is injected at a spray rate of 0.5 L / min at the side feeding port of zone Ⅲ. The vacuum degree of zone Ⅳ is adjusted to -0.08 MPa, 0.1 parts of silicone lubricant are injected into the melt pump of zone Ⅴ, high shear mixing is carried out at 800 rpm for 3 min, the melt is extruded through a hanger die with an aperture of 3 mm, passed into a 25 ℃ water tank for cooling, hauled at 12 m / min, pelletized into 4 mm length particles, centrifuged and dehydrated at 1200 rpm for 5 min, and then dried with hot air at 80 ℃ for 30 min;

[0043] S4. Place the dried particles into the furnace chamber, introduce nitrogen at a flow rate of 5 L / min, raise the temperature to 195°C at 15°C / min and hold the temperature constant for 30 min, then lower the temperature to 145°C at 5°C / min and hold the temperature constant for 45 min, and finally lower the temperature to 60°C at 2°C / min, turn off the heating, and allow the mixture to cool naturally to room temperature;

[0044] S5. Add 0.5 wt% didodecyl dimethyl ammonium chloride to deionized water, stir and dissolve at 40°C for 20 minutes, and then filter through a 100-mesh screen to prepare a coating solution. The particles stay in the coating solution at 60°C for 20 seconds, and then dry with hot air at 100°C for 5 minutes to form a 70 nm antistatic layer. Randomly sample and test the surface resistance ≤10 9 Ω qualified products are sealed in packaging.

[0045] Example 2: Preparation of high-elasticity recycled polyester material for chemical fiber. The specific preparation steps are as follows:

[0046] S1. Place 12 parts of glass fiber in a high-speed mixer, spray 0.4 parts of a silane coupling agent KH-550 and 6 parts of anhydrous ethanol mixture, stir at 85°C and 1200 rpm for 15 minutes, and then dry at 105°C to obtain activated glass fiber; add 6 parts of aluminum hypophosphite and 4 parts of melamine cyanurate to a ball mill, and under nitrogen protection, ball mill at 400 rpm for 60 minutes to make D50 ≤ 2.5 μm to obtain a flame retardant compound powder; mix 0.15 parts of sodium aryl phosphate with 1 part of anhydrous ethanol, and ultrasonically disperse at 200 W power for 10 minutes to obtain a β crystal nucleating agent-ethanol dispersion;

[0047] S2. Set the internal mixer to 240°C, add 75 parts of modified recycled polyester, 30 parts of modified bio-based elastomer, and 10 parts of POE-g-MAH, mix at 60 rpm for 8 minutes, then add 0.8 parts of antioxidant and 2 parts of carbon black masterbatch and continue mixing for 3 minutes; cool the internal mixer to 210°C, add 10 parts of flame retardant compound powder, increase the rotor speed to 90 rpm and mix for 5 minutes, then add 12 parts of activated glass fiber in three times, each time with an interval of 90 seconds; the melt is discharged from the internal mixer and passed into a supercritical device, and dynamically mixed at 12 MPa and 120°C for 5 minutes to form a 0.3 μm interpenetrating grid;

[0048] S3, open the twin-screw extruder, set the temperature of each zone: 200 ℃ in zone Ⅰ, 210 ℃ in zone Ⅱ, 220 ℃ in zone Ⅲ, 230 ℃ in zone Ⅳ, 245 ℃ in zone Ⅴ, and 260 ℃ in zone Ⅵ. After each temperature zone reaches the set temperature, keep warm for 30 min; the screw speed is 320 rpm, the melt after supercritical treatment is added to the main feeding port of zone Ⅰ, and the β crystal nucleating agent-ethanol dispersion is injected at a spray rate of 0.5 L / min in the side feeding port of zone Ⅲ. The vacuum degree in zone Ⅳ is adjusted to -0.08 MPa, 0.3 parts of silicone lubricant are injected into the melt pump of zone Ⅴ, high shear mixing is carried out at 800 rpm for 3 min, the melt is extruded through a hanger die with an aperture of 3 mm, passed into a 25 ℃ water tank for cooling, hauled at 12 m / min, pelletized into 4 mm length particles, centrifuged and dehydrated at 1200 rpm for 5 min, and then dried with hot air at 80 ℃ for 30 min;

[0049] S4. Place the dried particles into the furnace chamber, introduce nitrogen at a flow rate of 5 L / min, raise the temperature to 195°C at 15°C / min and hold the temperature constant for 30 min, then lower the temperature to 145°C at 5°C / min and hold the temperature constant for 45 min, and finally lower the temperature to 60°C at 2°C / min, turn off the heating, and allow the mixture to cool naturally to room temperature;

[0050] S5. Add 1.0 wt% didodecyl dimethyl ammonium chloride to deionized water, stir and dissolve at 40°C for 20 minutes, and then filter through a 100-mesh screen to prepare a coating solution. The particles stay in the coating solution at 60°C for 20 seconds, and then dry with hot air at 100°C for 5 minutes to form a 90 nm antistatic layer. Randomly sample and test the surface resistance ≤10 9 Ω qualified products are sealed in packaging.

[0051] Example 3: Preparation of high-elasticity recycled polyester material for chemical fiber. The specific preparation steps are as follows:

[0052] S1. Place 10 parts of glass fiber in a high-speed mixer, spray 0.3 parts of a silane coupling agent KH-550 and 5 parts of anhydrous ethanol mixture, stir at 85°C and 1200 rpm for 15 minutes, and then dry at 105°C to obtain activated glass fiber; add 5 parts of aluminum hypophosphite and 3 parts of melamine cyanurate to a ball mill, and under nitrogen protection, ball mill at 400 rpm for 60 minutes to make D50 ≤ 2.5 μm to obtain a flame retardant compound powder; mix 0.1 parts of sodium aryl phosphate with 1 part of anhydrous ethanol, and ultrasonically disperse at 200 W power for 10 minutes to obtain a β crystal nucleating agent-ethanol dispersion;

[0053] S2. Set the internal mixer to 240°C, add 70 parts of modified recycled polyester, 25 parts of modified bio-based elastomer, and 7 parts of POE-g-MAH, mix at 60 rpm for 8 minutes, then add 0.5 parts of antioxidant and 1.5 parts of carbon black masterbatch and continue mixing for 3 minutes; cool the internal mixer to 210°C, add 8 parts of flame retardant compound powder, increase the rotor speed to 90 rpm and mix for 5 minutes, then add 10 parts of activated glass fiber in three times, each time with an interval of 90 seconds; the melt is discharged from the internal mixer and passed into a supercritical device, and dynamically mixed at 10 MPa and 120°C for 5 minutes to form a 0.3 μm interpenetrating grid;

[0054] S3, open the twin-screw extruder, set the temperature of each zone: 200 ℃ in zone I, 210 ℃ in zone II, 220 ℃ in zone III, 230 ℃ in zone IV, 245 ℃ in zone V, and 260 ℃ in zone VI. After each temperature zone reaches the set temperature, keep warm for 30 min; the screw speed is 320 rpm, the melt after supercritical treatment is added to the main feeding port of zone I, and the β crystal nucleating agent-ethanol dispersion is injected at a spray rate of 0.5 L / min in the side feeding port of zone III. The vacuum degree of zone IV is adjusted to -0.08 MPa, 0.2 parts of silicone lubricant are injected into the melt pump of zone V, high shear mixing is carried out at 800 rpm for 3 min, the melt is extruded through a hanger die with an aperture of 3 mm, cooled in a water tank at 25 ℃, pulled at 12 m / min, pelletized into 4 mm length particles, centrifuged and dehydrated at 1200 rpm for 5 min, and then dried with hot air at 80 ℃ for 30 min;

[0055] S4. Place the dried particles into the furnace chamber, introduce nitrogen at a flow rate of 5 L / min, raise the temperature to 195°C at 15°C / min and hold the temperature constant for 30 min, then lower the temperature to 145°C at 5°C / min and hold the temperature constant for 45 min, and finally lower the temperature to 60°C at 2°C / min, turn off the heating, and allow the mixture to cool naturally to room temperature;

[0056] S5. Add 0.8 wt% didodecyl dimethyl ammonium chloride to deionized water, stir and dissolve at 40°C for 20 minutes, and then filter through a 100-mesh screen to prepare a coating solution. The particles stay in the coating solution at 60°C for 20 seconds, and then dry with hot air at 100°C for 5 minutes to form a 90 nm antistatic layer. Randomly sample and test the surface resistance ≤109 Ω qualified products are sealed in packaging.

[0057] Example 4, preparation of modified recycled polyester, the specific preparation steps are as follows:

[0058] A1. Place 100 g of recycled polyester chips crushed to 2 mm in an autoclave, evacuate to -0.1 MPa, inject liquid carbon dioxide to a pressure of 12 MPa, raise the temperature to 115°C, and evenly inject 0.6 g of epoxy chain extender using an atomizing spray gun. Maintain constant temperature and pressure while stirring at 150 rpm for 45 min to allow the chain extender to penetrate into the chips. After the reaction is completed, slowly reduce the pressure to normal pressure. After the temperature drops to room temperature, remove the modified recycled polyester chips.

[0059] A2. 0.8 g of fumed silica with a particle size of 50 nm was placed in a radio frequency plasma furnace and introduced into a mixture of argon and ethylene with a volume ratio of 95:5 at 300 W for 15 min to form surface active sites. The plasma-activated nano-silica and 100 g of A1-modified recycled polyester fragments were simultaneously added to a fluidized bed reactor, sprayed with 2.4 g of ε-caprolactone monomer, and reacted at 120°C for 2 h under a nitrogen atmosphere to generate polycaprolactone-grafted silica composite particles. The thickness of the grafted layer was precisely controlled to 65 ± 5 nm.

[0060] A3. Add 100 g of A2 product, 0.3 g of aromatic phosphate nucleating agent, and 0.1 g of organic carboxylate nucleating aid into a high-speed mixer, and dry mix them at 80 ° C and 2000 rpm for 10 min. The uniformly mixed material is sent to a gradient cooling crystallizer. In the first stage, 280 ° C → 230 ° C, the cooling rate is 20 ° C / s, and in the second stage, 230 ° C → 195 ° C, the cooling rate is 5 ° C / s, and the material is cooled to 195 ° C and kept at a constant temperature for 90 s to form a spherulite structure with an average diameter of 380 nm.

[0061] Example 5, preparation of modified bio-based polyether ester elastomer, the specific preparation steps are as follows:

[0062] B1: 100 g of bio-based polyether ester elastomer particles and 0.8 g of di-tert-butyl peroxide were mixed at 180°C and 50 rpm for 90 s. After mixing, the mixture was immediately cooled to 60°C with cold water and extracted with toluene for 24 h. The crosslinking degree was controlled at 35 ± 3% to obtain a pre-crosslinked elastomer.

[0063] B2, 100g of the pre-crosslinked elastomer obtained from B1 and 12g of ethylene furandicarboxylate monomer were added to a reactor, the reactor was evacuated to -0.095MPa, the temperature was raised to 245°C, 0.05g of tetrabutyl titanate was added, and a melt reaction was carried out at 100rpm for 40min to form 8-15nm rigid micro-domains. After the reaction, the reactor was cooled to room temperature, the copolymer was taken out, dissolved with acetone, poured into methanol for precipitation, and the product was filtered and dried in a vacuum drying oven at 60°C for 12h;

[0064] B3. Mix 100g of the block copolymer obtained from B2 with 2.5g of zinc acrylate on a two-roll mill, control the roll temperature to 170°C, and pass the mill 10 times at 15rpm to evenly disperse the metal ions in the block copolymer. Transfer the milled material to a hot press at 180°C and maintain the pressure for 10 minutes to form an ion cross-linking network between the metal ions and the block copolymer. After the hot pressing is completed, take out the sample and cool it naturally at room temperature to obtain the final modified bio-based polyether ester elastomer material.

[0065] Comparative Example 1: Preparation of high-elasticity recycled polyester material for chemical fiber. The specific preparation steps are as follows:

[0066] The remaining steps remain unchanged, except that the modified recycled polyester in Example 3 is replaced by recycled polyester without any treatment to prepare a high-elasticity recycled polyester material for chemical fiber.

[0067] Comparative Example 2: Preparation of high-elasticity recycled polyester material for chemical fiber. The specific preparation steps are as follows:

[0068] The remaining steps remain unchanged, except that the modified bio-based polyether ester elastomer in Example 3 is replaced by a bio-based polyether ester elastomer without any treatment to prepare a high-elasticity recycled polyester material for chemical fiber.

[0069] Performance Testing

[0070]

[0071]

[0072] The test data of Examples 1-3 show that after modification, the high elasticity recycled polyester material for chemical fiber has a tensile strength of 58-63 MPa, an elongation at break of 280%-330%, an elastic recovery rate of 85%-90%, a limiting oxygen index of 27%-29%, and a surface resistance of 10 9 Ω, heat deformation temperature 78-82℃, all performances are better than the unmodified comparative materials, realizing the high-value recycling of waste polyester and significant environmental benefits.

[0073] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A highly elastic recycled polyester material for chemical fiber, characterized by: The invention comprises the following raw materials in parts by weight: 8-12 parts of glass fiber, 0.2-0.4 parts of silane coupling agent KH-550, 4-6 parts of anhydrous ethanol, 4-6 parts of aluminum hypophosphite, 2-4 parts of melamine cyanurate, 0.05-0.15 parts of sodium aryl phosphate, 65-75 parts of modified recycled polyester, 20-30 parts of modified bio-based elastomer, 5-10 parts of maleic anhydride grafted polyolefin elastomer, 0.3-0.8 parts of antioxidant, 1-2 parts of carbon black masterbatch, 0.1-0.3 parts of silicone lubricant, and 5-10 parts of didodecyl dimethyl ammonium chloride.

2. The high-elasticity recycled polyester material for chemical fiber according to claim 1, characterized in that: The glass fiber has a diameter of 5-8 μm; the grafting rate of the maleic anhydride grafted polyolefin elastomer is 1.0-1.5%, and the melt index at 190° C. and 2.16 kg is 3-8 g / 10 min; and the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:

1.

3. The high-elasticity recycled polyester material for chemical fiber according to claim 1, characterized in that: The modified recycled polyester is specifically prepared in the following steps: A1. Place recycled polyester fragments crushed to 2 mm in an autoclave, evacuate to -0.1 MPa, inject liquid carbon dioxide to a pressure of 12 MPa, raise the temperature to 115°C, and evenly inject an epoxy chain extender using an atomizing spray gun. Maintain constant temperature and pressure while stirring at 150 rpm for 45 minutes to allow the chain extender to penetrate the fragments. After the reaction is completed, slowly reduce the pressure to normal pressure. After the temperature drops to room temperature, remove the modified recycled polyester fragments. A2: Fumed silica with a particle size of 50 nm was placed in a radio frequency plasma furnace and treated with an argon / ethylene mixture at 300 W for 15 minutes to form surface active sites. The plasma-activated nano-silica and A1-modified recycled polyester fragments were simultaneously added to a fluidized bed reactor, sprayed with ε-caprolactone monomer, and reacted at 120°C for 2 hours under a nitrogen atmosphere to produce polycaprolactone-grafted silica composite particles. A3. Add product A2, an aromatic phosphate nucleating agent, and an organic carboxylate nucleating aid into a high-speed mixer and dry-mix at 80°C and 2000 rpm for 10 min. The uniformly mixed material is sent into a gradient cooling crystallizer, cooled to 195°C and maintained at this temperature for 90 seconds to form a spherulite structure with an average diameter of 380 nm.

4. The high-elasticity recycled polyester material for chemical fiber according to claim 3, characterized in that: The mass ratio of the recycled polyester fragments to the epoxy chain extender in A1 is 100:0.6; the epoxy chain extender is a styrene-acrylate copolymer with an epoxy value of 0.45 mol / 100g; The volume ratio of argon and ethylene in A2 is 95:5, and the mass ratio of silica, A1 modified recycled polyester fragments, and ε-caprolactone monomer is 1:125:3; plasma activation allows the graft layer thickness to be precisely controlled to 65±5 nm; The mass ratio of the A2 product, the aryl phosphate nucleating agent, and the organic carboxylate nucleating aid in A3 is 100:0.3:0.1; the aryl phosphate nucleating agent is sodium bis(4-tert-butylphenyl) phosphate, and the organic carboxylate nucleating aid is a mixture of sodium benzoate and sodium stearate in a mass ratio of 3:

2.

5. The high-elasticity recycled polyester material for chemical fiber according to claim 3, characterized in that: The modified recycled polyester uses a composite nucleating agent to induce nano-crystallization and adopts gradient cooling crystallization control. In the first stage, 280°C→230°C, the cooling rate is 20°C / s, and in the second stage, 230°C→195°C, the cooling rate is 5°C / s. The modified recycled polyester constructs a core-shell-crystal triple structure through supercritical chain extension + nano-grafting.

6. The high-elasticity recycled polyester material for chemical fiber according to claim 1, characterized in that: The modified bio-based polyether ester elastomer is specifically prepared in the following steps: B1. Bio-based polyether ester elastomer particles and di-tert-butyl peroxide were mixed at 180°C and 50 rpm for 90 seconds. After mixing, the mixture was immediately cooled to 60°C with cold water. The crosslinking degree was controlled by solvent extraction to obtain a pre-crosslinked elastomer. B2. The pre-crosslinked elastomer obtained in B1 and ethylene furandicarboxylate monomer were added to a reactor, the reactor was evacuated to -0.095 MPa, the temperature was raised to 245°C, tetrabutyl titanate was added, and a melt reaction was carried out at 100 rpm for 40 minutes to form 8-15 nm rigid microdomains. After the reaction was completed, the reactor was cooled to room temperature, the copolymer was taken out, dissolved in acetone, poured into methanol for precipitation, and the product was filtered and dried in a vacuum drying oven at 60°C for 12 hours; B3. Mix the block copolymer obtained in B2 with zinc acrylate on a two-roll mill, control the roll temperature at 170°C, and pass the mill 10 times at 15 rpm to evenly disperse the metal ions in the block copolymer. Transfer the milled material to a hot press at 180°C and maintain the pressure for 10 minutes to form an ion cross-linking network between the metal ions and the block copolymer. After the hot pressing is completed, remove the sample and cool it naturally at room temperature to obtain the final modified bio-based polyether ester elastomer material.

7. The high-elasticity recycled polyester material for chemical fiber according to claim 6, characterized in that: The mass ratio of bio-based polyether ester elastomer particles to di-tert-butyl peroxide in B1 is 100:0.

8. The bio-based polyether ester elastomer is a block copolymer containing a polyether soft segment and an aromatic polyester hard segment, with a bio-based content of ≥30%, a melt index of 4-10 g / 10 min at 190°C and 2.16 kg, and a Shore D hardness of 35-45. B1 is modified using a solvent extraction method, wherein the pre-crosslinked elastomer particles are placed in a Soxhlet extractor with toluene as the extractant and extracted for 24 hours to remove the uncrosslinked portion, and the crosslinking degree is controlled at 35±3%. The mass ratio of the pre-crosslinked elastomer, ethylene furandicarboxylate monomer, and tetrabutyl titanate in B2 is 100:12:0.05; The mass ratio of the block copolymer and zinc acrylate in B3 is 100:2.5; the ionic crosslinking point density is 3.2×10 20 / cm 3 .

8. The high-elasticity recycled polyester material for chemical fiber according to claim 6, characterized in that: The modified bio-based polyether ester elastomer avoids excessive cross-linking through time-temperature coordinated control.

9. A method for preparing a highly elastic recycled polyester material for chemical fiber, characterized by: The specific steps include: S1. Place glass fiber in a high-speed mixer, spray a mixture of silane coupling agent KH-550 and anhydrous ethanol, stir at 85°C and 1200 rpm for 15 minutes, and then dry at 105°C to obtain activated glass fiber; add aluminum hypophosphite and melamine cyanurate to a ball mill, and ball mill at 400 rpm for 60 minutes under nitrogen protection to adjust D50 to ≤ 2.5 μm to obtain a flame retardant compound powder; mix sodium aryl phosphate with anhydrous ethanol, and ultrasonically disperse at 200 W power for 10 minutes to obtain a β-crystal nucleating agent-ethanol dispersion; S2. Set the internal mixer to 240°C, add modified recycled polyester, modified bio-based elastomer, and maleic anhydride grafted polyolefin elastomer, and mix at 60 rpm for 8 minutes. Then add antioxidant and carbon black masterbatch and continue mixing for 3 minutes. Cool the internal mixer to 210°C, add flame retardant compound powder, increase the rotor speed to 90 rpm and mix for 5 minutes. Then add activated glass fiber three times, with an interval of 90 seconds between each addition. The melt was discharged from the internal mixer and passed into a supercritical device, where it was dynamically mixed at 8-12 MPa and 120°C for 5 min to form an interpenetrating mesh of 0.3 μm. S3, open the twin-screw extruder, set the temperature of each zone: 200 ℃ in zone I, 210 ℃ in zone II, 220 ℃ in zone III, 230 ℃ in zone IV, 245 ℃ in zone V, and 260 ℃ in zone VI. After each temperature zone reaches the set temperature, keep warm for 30 min; the screw speed is 320 rpm, the melt after supercritical treatment is added to the main feeding port of zone I, and the β crystal nucleating agent-ethanol dispersion is injected at a spray rate of 0.5 L / min in the side feeding port of zone III. The vacuum degree in zone IV is adjusted to -0.08 MPa, and silicone lubricant is injected into the melt pump of zone V. 800 rpm high shear mixing is carried out for 3 min, and the melt is extruded through a hanger die with an aperture of 3 mm, passed into a 25 ℃ water tank for cooling, 12 m / min traction, pelletized into 4 mm length particles, centrifuged and dehydrated for 5 min at 1200 rpm, and then dried with hot air at 80 ℃ for 30 min; S4. Place the dried particles into the furnace chamber, introduce nitrogen at a flow rate of 5 L / min, raise the temperature to 195°C at 15°C / min and hold the temperature constant for 30 min, then lower the temperature to 145°C at 5°C / min and hold the temperature constant for 45 min, and finally lower the temperature to 60°C at 2°C / min, turn off the heating, and allow the mixture to cool naturally to room temperature; S5. Add 0.5-1.0 wt% didodecyl dimethyl ammonium chloride to deionized water, stir and dissolve at 40°C for 20 minutes, and then filter through a 100-mesh screen to prepare a coating solution. The particles stay in the coating solution at 60°C for 20 seconds, and then dry with hot air at 100°C for 5 minutes to form a 70-90 nm antistatic layer. Randomly sample and test the surface resistance ≤10 9 Ω qualified products are sealed in packaging.

10. The method for preparing a highly elastic recycled polyester material for chemical fiber according to claim 9, characterized in that: The S4 is a gradient crystallization operation, wherein the first stage is nucleation, and nitrogen gas is introduced at a flow rate of 5 L / min to prevent oxidation and yellowing; the second stage is crystal growth, and the resulting spherulite size is 250±30 nm.

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