A method for preparing a side-by-side composite regenerated polyester fiber

Abstract

The application discloses a preparation method of parallel composite regenerated polyester fibers and belongs to the technical field of regenerated polyester fiber preparation. The preparation method of the parallel composite regenerated polyester fibers takes PS microspheres as a template, adopts in-situ growth and calcination to prepare hollow SiO2, modifies the hollow SiO2 through a quaternary ammonium salt surfactant, and combines high and low viscosity double-component composite spinning technology to endow the composite regenerated polyester fibers with excellent radiation cooling performance, antibacterial performance, curling performance, rebound performance and textile processing applicability. The application realizes multifunctional integration of antibacterial performance, radiation cooling and structural curling in a single regenerated polyester system, expands the application of the regenerated polyester fibers in the field of high-value-added textiles, and has good environmental benefits and process feasibility.

Description

Technical Field

[0001] This invention relates to the field of recycled polyester fiber preparation technology, and in particular to a method for preparing parallel composite recycled polyester fibers. Background Technology

[0002] Recycled polyester fiber is a fiber made from waste polyester materials through recycling, processing, and re-spinning. It has significant advantages such as resource recyclability, energy conservation, and environmental protection. With the improvement of living standards and the increasing demand for health, comfort, and environmental protection, the functionalization of textiles has become an important development direction. Single-performance recycled polyester fibers can no longer meet the needs of high-end application scenarios. Developing recycled polyester fibers with functions such as antibacterial and radiation cooling has become an industry trend.

[0003] In existing technologies, studies have explored different pathways to enhance the functionality of recycled polyester fibers. For example, patent CN202111594767A (Yuyao Dafeng Chemical Fiber Co., Ltd.) prepared highly elastic thermally bonded composite fibers using core-sheath composite and parallel spinning techniques, but it focused on mechanical properties and did not address functional systems such as antibacterial and radiation cooling. On the other hand, patent CN202111580098A (Shanghai Defulun New Material Technology Co., Ltd.) used inorganic nanomaterial blending modification to impart antibacterial and UV-resistant properties to recycled polyester fibers, but it still has the following limitations: 1. The antibacterial spectrum of inorganic nanoparticles is relatively limited; 2. High nanoparticle addition levels can easily lead to deterioration of melt rheology and spinning instability; 3. Radiation cooling function is not integrated, and there is a lack of design for fiber crimp elasticity.

[0004] Therefore, researching and developing a novel method for preparing recycled polyester fibers that combines radiation cooling, antibacterial properties, and resilience is of great significance for the development and application of recycled polyester fibers. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a method for preparing a parallel composite recycled polyester fiber. The composite recycled polyester fiber prepared by the method has excellent radiation cooling performance, antibacterial properties, and crimp resilience.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] This invention provides a method for preparing parallel-type composite recycled polyester fibers, comprising the following steps:

[0008] (1) Polyvinylpyrrolidone, 2,2′-azobisisobutylamidine dihydrochloride, styrene and water were mixed and reacted to obtain polystyrene microspheres;

[0009] (2) Mix polystyrene microspheres, silica precursor and first solvent and react them. Control the pH of the reaction system to 9-10 to form SiO2 particles on the surface of polystyrene microspheres to obtain PS / SiO2 particles.

[0010] (3) The PS / SiO2 particles are calcined to obtain hollow SiO2;

[0011] (4) The hollow SiO2, quaternary ammonium salt surfactant and second solvent are mixed and reacted to obtain quaternary ammonium salt modified hollow SiO2, which is then melt-blended with recycled polyester fiber foam to obtain the first masterbatch.

[0012] (5) The second masterbatch obtained by melt extrusion granulation of recycled polyester fiber foam is mixed and melted with the first masterbatch, and then nascent fiber is obtained by parallel composite spinning;

[0013] (6) The nascent fibers are stretched, curled, cut and shaped in sequence to obtain the parallel composite recycled polyester fibers.

[0014] The preparation method described in this invention achieves the preparation of parallel composite recycled polyester fibers through a single recycled polyester system. This is because only one type of recycled polyester fiber foam exists in the first masterbatch and the second masterbatch (i.e., the recycled polyester fiber foam described in steps (4) and (5) is the same).

[0015] In this invention, preferably, the recycled polyester fiber foam is a fiber foam produced from polyethylene terephthalate, which can be represented as PET foam.

[0016] More preferably, the content of polyethylene terephthalate in the recycled polyester fiber foam is 90wt%-95wt%.

[0017] Preferably, the reaction temperature in step (1) of this invention is 60°C-80°C; more preferably, it is 70°C.

[0018] Preferably, the molar ratio of polyvinylpyrrolidone and 2,2′-azobisisobutylamidine dihydrochloride in step (1) is (0.5-1):1; more preferably, it is 0.5:1.

[0019] In some specific embodiments of the present invention, step (1) specifically involves mixing PVP, AIBA and water, and then adding styrene for a heated reaction.

[0020] The water includes, but is not limited to, deionized water or distilled water.

[0021] The styrene was added dropwise.

[0022] In the above preparation method, after the reaction in step (1) is completed, post-treatments such as washing, centrifugation, and drying are also performed in sequence.

[0023] The present invention does not impose any particular limitation on the solvent used for washing, the conditions for centrifugation, or the method of drying; any solvent, conditions, or method known to those skilled in the art is acceptable.

[0024] In some specific embodiments of the present invention, the washing solvent is preferably a mixture of ethanol and water.

[0025] The drying process is preferably vacuum drying.

[0026] The vacuum drying temperature is preferably 45℃-55℃; more preferably 50℃.

[0027] Preferably, the reaction temperature in step (2) of this invention is 40℃-50℃, more preferably 40℃.

[0028] Preferably, in step (2), the silica precursor is selected from tetraethyl orthosilicate (TEOS) or methyl orthosilicate (TMOS).

[0029] Preferably, the mass ratio of the silica precursor to the polystyrene microspheres is (2-4):1.

[0030] In some specific embodiments of the present invention, step (2) specifically includes mixing PS microspheres and a first solvent and adjusting the pH of the mixture to 9-10, then adding a silica precursor to the mixture and reacting to obtain the PS / SiO2 particles.

[0031] The PS / SiO2 particles comprise polystyrene microspheres and silica particles composited on their surface.

[0032] The mixing process is preferably ultrasonic mixing.

[0033] The preferred ultrasonic mixing time is 30-60 min.

[0034] The preferred solvent for adjusting the pH of the mixture is ammonia.

[0035] The silica precursor is preferably added by dropwise addition.

[0036] The reaction involves the in-situ growth of SiO2 on the surface of PS microspheres.

[0037] The present invention does not specifically limit the calcination equipment to any calcination equipment known to those skilled in the art.

[0038] In some specific embodiments of the present invention, a muffle furnace is preferred.

[0039] The step (3) of this invention removes PS microspheres and controls the structure of hollow SiO2 by controlling the calcination temperature.

[0040] The hollow SiO2 prepared by the method described in this invention has a porous cavity structure.

[0041] Preferably, the calcination temperature in step (3) of this invention is 500℃-650℃; more preferably, it is 550℃.

[0042] Preferably, the heating rate of the calcination is 2-5℃ / min.

[0043] The preferred calcination time is 4-6 hours.

[0044] In the above preparation method, the quaternary ammonium salt modified hollow SiO2 in step (4) includes hollow SiO2 and quaternary ammonium salt surfactants loaded on its surface and / or the inner surface of the hollow SiO2 pores.

[0045] The melt viscosity was further improved by melt blending the quaternary ammonium salt modified hollow SiO2 with recycled polyester fiber foam.

[0046] Preferably, the reaction temperature in step (4) of this invention is 70℃-90℃; more preferably, it is 80℃.

[0047] Preferably, the quaternary ammonium salt surfactant in step (4) is selected from one or more of hexadecyltrimethylammonium bromide, dodecyltrimethylammonium chloride, and octadecyltrimethylammonium bromide;

[0048] Preferably, the mass of the quaternary ammonium salt surfactant is 15%-30% of the hollow SiO2; more preferably, it is 15% or 20%.

[0049] Preferably, in step (4), the mass of the quaternary ammonium salt modified hollow SiO2 in the first masterbatch is 3%-5% of the recycled polyester fiber foam.

[0050] Preferably, the intrinsic viscosity of the masterbatch is 0.7-0.75 dL / g; more preferably, it is 0.72 dL / g, 0.74 dL / g, or 0.75 dL / g.

[0051] Preferably, the viscosity of the recycled polyester fiber foam is 0.5-0.6 dL / g.

[0052] In some specific embodiments of the present invention, the specific operation of step (4) includes mixing the hollow SiO2 and the second solvent, then adding a quaternary ammonium salt surfactant, reacting to obtain quaternary ammonium salt modified hollow SiO2, and then melt-blending it with recycled polyester fiber foam to obtain the first masterbatch.

[0053] The present invention does not have any particular limitation on the equipment used for melt blending; any equipment known to those skilled in the art is acceptable.

[0054] In some specific embodiments of the present invention, a twin-screw extruder is preferably used. The preferred specific operation includes the following steps:

[0055] Quaternary ammonium salt modified hollow SiO2 and recycled polyester fiber foam were premixed and then melt-extruded and granulated using a twin-screw extruder.

[0056] The premixing speed is 950-1050 rpm, and the mixing time is 10-20 min.

[0057] During the melt extrusion process, the temperatures of each section of the twin-screw extruder are as follows: Zone I 255℃, Zone II 260℃, Zone III 265℃, Zone IV 270℃, and the die head temperature 265℃.

[0058] The process after melt extrusion also includes post-processing such as water cooling and pelletizing.

[0059] In the preparation method of the present invention, after the reaction in step (4) is completed, post-treatments such as centrifugation, washing, and drying are performed in sequence.

[0060] The preferred solvent for washing is anhydrous ethanol.

[0061] The drying process is preferably vacuum drying.

[0062] The vacuum drying temperature is preferably 60℃-80℃; more preferably 70℃.

[0063] Preferably, in step (2), the mass ratio of polystyrene microspheres to the first solvent is 1:(10-20); more preferably, it is 1:15, 1:18, or 1:20.

[0064] Preferably, the first solvent is selected from a mixture of an alcohol solvent and water;

[0065] Preferably, the volume ratio of the alcohol solvent to water is (3-4):1;

[0066] Preferably, the alcohol solvent is selected from ethanol, methanol, or isopropanol;

[0067] Preferably, the second solvent in step (4) is selected from anhydrous ethanol or anhydrous methanol.

[0068] This invention uses a first masterbatch as a high-viscosity component and a second masterbatch as a low-viscosity component, employing a high-low viscosity bicomponent composite spinning technology for the parallel composite spinning process. The hollow SiO2 can enrich polyester macromolecules through a filling effect and interfacial interaction, achieving a melt thickening effect.

[0069] In some specific embodiments of the present invention, the first masterbatch and the second masterbatch are separately metered and then sequentially melted and spun in parallel to obtain nascent fibers.

[0070] Preferably, in step (5), the spinneret of the parallel composite spinning is double "C" shaped;

[0071] Preferably, the spinning box temperature of the parallel composite spinning is 250℃-260℃;

[0072] The second masterbatch of the present invention is obtained by melt extrusion granulation of recycled polyester fiber foam.

[0073] Preferably, the viscosity of the recycled polyester fiber foam in step (5) is 0.5-0.6 dL / g; more preferably, it is 0.5-0.55 dL / g.

[0074] Preferably, the temperature of melt extrusion granulation in step (5) is 250℃-270℃; more preferably, it is 260℃.

[0075] After melting, a filtration process is also included to remove impurities and improve the quality of the final product. Preferably, the stretching ratio in step (6) is 1.5-2.2; more preferably 1.8-2.0; and in some specific embodiments of the present invention, it is preferably 1.8, 1.84, 1.86, or 1.88.

[0076] Preferably, the temperature for the shaping treatment is 110℃-140℃; more preferably, it is 120℃-130℃. In some specific embodiments of the present invention, it is preferably 120℃, 125℃, or 130℃.

[0077] This invention provides a side-by-side composite recycled polyester fiber, which is prepared by the above-described preparation method;

[0078] The parallel composite recycled polyester fiber described in this invention possesses excellent antibacterial properties, radiation cooling properties, crimping properties, and resilience.

[0079] Preferably, the visible light reflectance of the parallel composite recycled polyester fiber is 90%-95%;

[0080] Preferably, the Escherichia coli inhibition rate of the parallel-type composite recycled polyester fiber is 98%-99.6%;

[0081] Preferably, the crimp rate of the parallel composite recycled polyester fiber is 19%-22%.

[0082] Compared with the prior art, the preparation method of the parallel composite recycled polyester fiber provided by the present invention includes the following steps: (1) mixing polyvinylpyrrolidone, 2,2′-azobisisobutylamidine dihydrochloride, styrene and water to react and obtain polystyrene microspheres; (2) mixing polystyrene microspheres, silica precursor and first solvent to react, controlling the pH value of the reaction system to 9-10, forming SiO2 particles on the surface of polystyrene microspheres to obtain PS / SiO2 particles; (3) calcining the PS / SiO2 particles. (3) Calcination to obtain hollow SiO2; (4) Mix the hollow SiO2, quaternary ammonium salt surfactant and the second solvent to react and obtain quaternary ammonium salt modified hollow SiO2, and melt-blend it with recycled polyester fiber foam to obtain the first masterbatch; (5) Mix and melt the second masterbatch obtained by melt extrusion granulation of recycled polyester fiber foam with the first masterbatch, and obtain nascent fiber by parallel composite spinning; (6) Stretch, crimp, cut and shape the nascent fiber in sequence to obtain the parallel composite recycled polyester fiber. The preparation method uses PS microspheres as templates, and prepares hollow SiO2 by in-situ growth and calcination, and modifies the hollow SiO2 with quaternary ammonium salt surfactant, and combines high and low viscosity bicomponent composite spinning technology to give the composite recycled polyester fiber excellent radiation cooling performance, antibacterial performance, crimp performance, resilience performance and textile processing applicability. This invention achieves multifunctional integration of antibacterial properties, radiation cooling, and structural crimping in a single recycled polyester system, expanding the application of recycled polyester fibers in the field of high value-added textiles, and has good environmental benefits and process feasibility. Attached Figure Description

[0083] Figure 1 This is an electron microscope image of the PS microspheres prepared in Example 1. Detailed Implementation

[0084] To further illustrate the present invention, the preparation method of the parallel composite recycled polyester fiber provided by the present invention will be described in detail below with reference to the embodiments.

[0085] The PET (polyethylene terephthalate) content in the following PET foam (i.e., the recycled polyester fiber foam of the present invention) is 90wt%-95wt%.

[0086] The PET foam is a fiber foam produced from polyethylene terephthalate.

[0087] Example 1

[0088] S1. Preparation of PS microspheres: 0.5 mol of PVP and 1 mol of AIBA were added to deionized water while stirring. Then, 0.5 mol of styrene monomer was added dropwise to the above solution. The mixture was heated to 70°C and kept at that temperature for 24 h. The mixture was washed with ethanol and water, centrifuged, and then vacuum dried at 50°C for 12 h to obtain PS microspheres.

[0089] S2. Preparation of PS / SiO2 particles: Take 10g of PS microspheres synthesized in step S1 and disperse them in a mixture of 150g of ethanol and deionized water (volume ratio of ethanol to deionized water is 4:1). Sonicate for 45min to obtain PS dispersion. Add ammonia to the dispersion to adjust the pH to 9, then slowly add 30mL of TEOS and stir continuously at 40℃ for 5h to allow SiO2 to grow on the surface of PS microspheres and form PS / SiO2 particles.

[0090] S3. Preparation of hollow SiO2: The PS / SiO2 particles synthesized in step S2 are placed in a muffle furnace and heated to 550°C at a rate of 2°C / min. The calcination is carried out for 4 hours to remove the PS particles and obtain hollow SiO2.

[0091] S4. Modified hollow SiO2: Take 10g of hollow SiO2 obtained in step S3 and disperse it in 200g of anhydrous ethanol. Sonicate for 45min, then add 2g of hexadecyltrimethylammonium bromide and heat to 80℃ for 7h. After the reaction is completed, centrifuge to obtain the precipitate, wash it 4 times with anhydrous ethanol, and vacuum dry it at 75℃ for 18h to obtain quaternary ammonium salt modified hollow SiO2.

[0092] S5. Preparation of high-viscosity component: The quaternary ammonium salt modified hollow SiO2 obtained in step S4 is mixed with PET foam with a viscosity of 0.55 dL / g (quaternary ammonium salt modified hollow SiO2 content accounts for 3%). The mixing time is 15 min and the mixing speed is 1000 rpm. The premix is ​​fed into a twin-screw extruder. The temperatures of each section of the twin-screw extruder are: Zone I 255℃, Zone II 260℃, Zone III 265℃, Zone IV 270℃, and the die head temperature is 265℃. The melt is extruded, water-cooled, and pelletized to obtain the first component masterbatch. Its viscosity is tested to be increased to 0.72 dL / g.

[0093] S6. Preparation of low viscosity component: PET foam with a viscosity of 0.55 dL / g is fed into a single screw extruder, the temperature is set to 260℃, and the second component masterbatch is obtained after atmospheric pressure melt extrusion granulation.

[0094] S7. The first component masterbatch and the second component masterbatch obtained in steps S5 and S6 are fed into a twin-screw spinning machine, melted and metered respectively, and then spun into nascent fibers through double "C" type spinnerets.

[0095] S8. The nascent fibers obtained in step S7 are stretched, crimped, cut, and shaped. The stretching ratio is 1.8, and the heat setting temperature is 120℃ to obtain functional parallel composite recycled polyester staple fibers.

[0096] Example 2

[0097] S1. Preparation of PS microspheres: 0.8 mol of PVP and 1.6 mol of AIBA were added to deionized water while stirring. Then, 1 mol of styrene monomer was added dropwise to the above solution. The solution was heated to 80°C and kept at that temperature for 24 h. The solution was washed with ethanol and water, centrifuged, and vacuum dried at 50°C for 12 h to obtain PS microspheres.

[0098] S2. Preparation of PS / SiO2 particles: Take 10g of PS microspheres synthesized in step S1 and disperse them in a mixture of 150g of ethanol and deionized water (volume ratio of ethanol to deionized water is 3:1). Sonicate for 45min to obtain PS dispersion. Add ammonia to the dispersion to adjust the pH to 9, then slowly add 25mL of TEOS and stir continuously at 40℃ for 5h to allow SiO2 to grow on the surface of PS microspheres and form PS / SiO2 particles.

[0099] S3. Preparation of hollow SiO2: The PS / SiO2 particles synthesized in step S2 are placed in a muffle furnace and heated to 550°C at a rate of 2°C / min. The calcination is carried out for 4 hours to remove the PS particles and obtain hollow SiO2.

[0100] S4. Modified hollow SiO2: Take 10g of hollow SiO2 obtained in step S3 and disperse it in 150g of anhydrous ethanol. Sonicate for 45min, then add 2g of cetyltrimethylammonium bromide and heat to 80℃ for 7h. After the reaction is completed, centrifuge to obtain the precipitate, wash it 4 times with anhydrous ethanol, and vacuum dry it at 75℃ for 18h to obtain quaternary ammonium salt modified hollow SiO2.

[0101] S5. Preparation of high-viscosity component: The quaternary ammonium salt modified hollow SiO2 obtained in step S4 is mixed with PET foam with a viscosity of 0.55 dL / g (quaternary ammonium salt modified hollow SiO2 content accounts for 4%). The mixing time is 15 min and the mixing speed is 1000 rpm. The premix is ​​fed into a twin-screw extruder. The temperatures of each section of the twin-screw extruder are: Zone I 255℃, Zone II 260℃, Zone III 265℃, Zone IV 270℃, and the die head temperature is 265℃. The melt is extruded, water-cooled, and pelletized to obtain the first component masterbatch. Its viscosity is tested to be increased to 0.74 dL / g.

[0102] S6. Preparation of low viscosity component: PET foam with a viscosity of 0.55 dL / g is fed into a single screw extruder, the temperature is set to 260℃, and the second component masterbatch is obtained after atmospheric pressure melt extrusion granulation.

[0103] S7. The first component masterbatch and the second component masterbatch obtained in steps S5 and S6 are fed into a twin-screw spinning machine, melted and metered respectively, and then spun into nascent fibers through double "C" type spinnerets.

[0104] S8. The nascent fibers obtained in step S7 are stretched, crimped, cut, and shaped. The stretching ratio is 1.84, and the heat setting temperature is 125℃ to obtain functional parallel composite recycled polyester staple fibers.

[0105] Example 3

[0106] S1. Preparation of PS microspheres: 1.2 mol of PVP and 2.4 mol of AIBA were added to deionized water while stirring. Then, 1.5 mol of styrene monomer was added dropwise to the above solution. The mixture was heated to 80°C and kept at that temperature for 24 h. The mixture was washed with ethanol and water, centrifuged, and then vacuum dried at 50°C for 12 h to obtain PS microspheres.

[0107] S2. Preparation of PS / SiO2 particles: Take 10g of PS microspheres synthesized in step S1 and disperse them in a mixture of 200g of ethanol and deionized water (volume ratio of ethanol to deionized water is 4:1). Sonicate for 45min to obtain PS dispersion. Add ammonia to the dispersion to adjust the pH to 9, then slowly add 30mL of TEOS and stir continuously at 40℃ for 5h to allow SiO2 to grow on the surface of PS microspheres and form PS / SiO2 particles.

[0108] S3. Preparation of hollow SiO2: The PS / SiO2 particles synthesized in step S2 are placed in a muffle furnace and heated to 550°C at a rate of 3°C / min. The mixture is calcined for 4 hours to remove the PS particles and obtain hollow SiO2.

[0109] S4. Modified hollow SiO2: Take 10g of hollow SiO2 obtained in step S3 and disperse it in 200g of anhydrous ethanol. Sonicate for 45min, then add 1.5g of cetyltrimethylammonium bromide and heat to 80℃ for 7h. After the reaction is completed, centrifuge to obtain the precipitate, wash it 4 times with anhydrous ethanol, and vacuum dry it at 75℃ for 18h to obtain quaternary ammonium salt modified hollow SiO2.

[0110] S5. Preparation of high-viscosity component: The quaternary ammonium salt modified hollow SiO2 obtained in step S4 is mixed with PET foam with a viscosity of 0.5 dL / g (quaternary ammonium salt modified hollow SiO2 content accounts for 4%). The mixing time is 15 min and the mixing speed is 1000 rpm. The premix is ​​fed into a twin-screw extruder. The temperatures of each section of the twin-screw extruder are: Zone I 255℃, Zone II 260℃, Zone III 265℃, Zone IV 270℃, and the die head temperature is 265℃. The melt is extruded, water-cooled, and pelletized to obtain the first component masterbatch. Its viscosity is tested to be increased to 0.75 dL / g.

[0111] S6. Preparation of low viscosity component: PET foam with a viscosity of 0.5 dL / g is fed into a single screw extruder, the temperature is set to 260℃, and the second component masterbatch is obtained after atmospheric pressure melt extrusion granulation.

[0112] S7. The first component masterbatch and the second component masterbatch obtained in steps S5 and S6 are fed into a twin-screw spinning machine, melted and metered respectively, and then spun into nascent fibers through double "C" type spinnerets.

[0113] S8. The nascent fibers obtained in step S7 are stretched, crimped, cut, and shaped. The stretching ratio is 1.86, and the heat setting temperature is 120℃ to obtain functional parallel composite recycled polyester staple fibers.

[0114] Example 4

[0115] S1. Preparation of PS microspheres: 1.5 mol of PVP and 3 mol of AIBA were added to deionized water while stirring. Then, 2.1 mol of styrene monomer was added dropwise to the above solution. The mixture was heated to 70°C and kept at that temperature for 24 h. The mixture was washed with ethanol and water, centrifuged, and then vacuum dried at 50°C for 12 h to obtain PS microspheres.

[0116] S2. Preparation of PS / SiO2 particles: Take 10g of PS microspheres synthesized in step S1 and disperse them in a mixture of 200g of ethanol and deionized water (volume ratio of ethanol to deionized water is 3:1). Sonicate for 45min to obtain PS dispersion. Add ammonia to the dispersion to adjust the pH to 9, then slowly add 35mL of TEOS and stir continuously at 40℃ for 5h to allow SiO2 to grow on the surface of PS microspheres and form PS / SiO2 particles.

[0117] S3. Preparation of hollow SiO2: The PS / SiO2 particles synthesized in step S2 are placed in a muffle furnace and heated to 550°C at a rate of 2°C / min. The calcination is carried out for 4 hours to remove the PS particles and obtain hollow SiO2.

[0118] S4. Modified hollow SiO2: Take 10g of hollow SiO2 obtained in step S3 and disperse it in 250g of anhydrous ethanol. Sonicate for 45min, then add 2g of dodecyltrimethylammonium chloride, heat to 80℃ and react continuously for 7h. After the reaction is completed, centrifuge to obtain the precipitate, wash it 4 times with anhydrous ethanol, and vacuum dry it at 75℃ for 18h to obtain quaternary ammonium salt modified hollow SiO2.

[0119] S5. Preparation of high-viscosity component: The quaternary ammonium salt modified hollow SiO2 obtained in step S4 is mixed with PET foam with a viscosity of 0.55 dL / g (quaternary ammonium salt modified hollow SiO2 content accounts for 5%). The mixing time is 15 min and the mixing speed is 1000 rpm. The premix is ​​fed into a twin-screw extruder. The temperatures of each section of the twin-screw extruder are: Zone I 255℃, Zone II 260℃, Zone III 265℃, Zone IV 270℃, and the die head temperature is 265℃. The melt is extruded, water-cooled, and pelletized to obtain the first component masterbatch. Its viscosity is tested to be increased to 0.75 dL / g.

[0120] S6. Preparation of low viscosity component: PET foam with a viscosity of 0.55 dL / g is fed into a single screw extruder, the temperature is set to 260℃, and the second component masterbatch is obtained after atmospheric pressure melt extrusion granulation.

[0121] S7. The first component masterbatch and the second component masterbatch obtained in steps S5 and S6 are fed into a twin-screw spinning machine, melted and metered respectively, and then spun into nascent fibers through double "C" type spinnerets.

[0122] S8. The nascent fibers obtained in step S7 are stretched, crimped, cut, and shaped. The stretching ratio is 1.86, and the heat setting temperature is 130℃ to obtain functional parallel composite recycled polyester staple fibers.

[0123] Example 5

[0124] S1. Preparation of PS microspheres: 2 mol of PVP and 4 mol of AIBA were added to deionized water while stirring. Then, 3 mol of styrene monomer was added dropwise to the above solution. The solution was heated to 70°C and kept at that temperature for 24 h. The solution was washed with ethanol and water, centrifuged, and vacuum dried at 50°C for 12 h to obtain PS microspheres.

[0125] S2. Preparation of PS / SiO2 particles: Take 10g of PS microspheres synthesized in step S1 and disperse them in a mixture of 150g of ethanol and deionized water (volume ratio of ethanol to deionized water is 4:1). Sonicate for 45min to obtain PS dispersion. Add ammonia to the dispersion to adjust the pH to 9, then slowly add 30mL of TEOS and stir continuously at 40℃ for 5h to allow SiO2 to grow on the surface of PS microspheres and form PS / SiO2 particles.

[0126] S3. Preparation of hollow SiO2: The PS / SiO2 particles synthesized in step S2 are placed in a muffle furnace and heated to 550°C at a rate of 2°C / min. The calcination is carried out for 4 hours to remove the PS particles and obtain hollow SiO2.

[0127] S4. Modified hollow SiO2: Take 10g of hollow SiO2 obtained in step S3 and disperse it in 200g of anhydrous ethanol. Sonicate for 45min, then add 1.5g of dodecyltrimethylammonium chloride, heat to 80℃ and react continuously for 7h. After the reaction is completed, centrifuge to obtain the precipitate, wash it 4 times with anhydrous ethanol, and vacuum dry it at 75℃ for 18h to obtain quaternary ammonium salt modified hollow SiO2.

[0128] S5. Preparation of high-viscosity component: The quaternary ammonium salt modified hollow SiO2 obtained in step S4 is mixed with PET foam with a viscosity of 0.55 dL / g (quaternary ammonium salt modified hollow SiO2 content accounts for 3%). The mixing time is 15 min and the mixing speed is 1000 rpm. The premix is ​​fed into a twin-screw extruder. The temperatures of each section of the twin-screw extruder are: Zone I 255℃, Zone II 260℃, Zone III 265℃, Zone IV 270℃, and the die head temperature is 265℃. The melt is extruded, water-cooled, and pelletized to obtain the first component masterbatch. Its viscosity is tested to be increased to 0.72 dL / g.

[0129] S6. Preparation of low viscosity component: PET foam with a viscosity of 0.55 dL / g is fed into a single screw extruder, the temperature is set to 260℃, and the second component masterbatch is obtained after atmospheric pressure melt extrusion granulation.

[0130] S7. The first component masterbatch and the second component masterbatch obtained in steps S5 and S6 are fed into a twin-screw spinning machine, melted and metered respectively, and then spun into nascent fibers through double "C" type spinnerets.

[0131] S8. The nascent fibers obtained in step S7 are stretched, crimped, cut, and shaped. The stretching ratio is 1.86, and the heat setting temperature is 120℃ to obtain functional parallel composite recycled polyester staple fibers.

[0132] Example 6

[0133] S1. Preparation of PS microspheres: 2.5 mol of PVP and 5 mol of AIBA were added to deionized water while stirring. Then, 4 mol of styrene monomer was added dropwise to the above solution. The solution was heated to 70°C and kept at that temperature for 24 h. The solution was washed with ethanol and water, centrifuged, and vacuum dried at 50°C for 12 h to obtain PS microspheres.

[0134] S2. Preparation of PS / SiO2 particles: Take 10g of PS microspheres synthesized in step S1 and disperse them in a mixture of 180g of ethanol and deionized water (volume ratio of ethanol to deionized water is 4:1). Sonicate for 45min to obtain PS dispersion. Add ammonia to the dispersion to adjust the pH to 9, then slowly add 35mL of TEOS and stir continuously at 40℃ for 5h to allow SiO2 to grow on the surface of PS microspheres and form PS / SiO2 particles.

[0135] S3. Preparation of hollow SiO2: The PS / SiO2 particles synthesized in step S2 are placed in a muffle furnace and heated to 550°C at a rate of 2°C / min. The calcination is carried out for 4 hours to remove the PS particles and obtain hollow SiO2.

[0136] S4. Modified hollow SiO2: Take 10g of hollow SiO2 obtained in step S3 and disperse it in 220g of anhydrous ethanol. Sonicate for 45min, then add 2g of octadecyltrimethylammonium bromide and heat to 80℃ for 7h. After the reaction is completed, centrifuge to obtain the precipitate, wash it 4 times with anhydrous ethanol, and vacuum dry it at 75℃ for 18h to obtain quaternary ammonium salt modified hollow SiO2.

[0137] S5. Preparation of high-viscosity component: The quaternary ammonium salt modified hollow SiO2 obtained in step S4 is mixed with PET foam with a viscosity of 0.55 dL / g (quaternary ammonium salt modified hollow SiO2 content accounts for 5%). The mixing time is 15 min and the mixing speed is 1000 rpm. The premix is ​​fed into a twin-screw extruder. The temperatures of each section of the twin-screw extruder are: Zone I 255℃, Zone II 260℃, Zone III 265℃, Zone IV 270℃, and the die head temperature is 265℃. The melt is extruded, water-cooled, and pelletized to obtain the first component masterbatch. Its viscosity is tested to be increased to 0.75 dL / g.

[0138] S6. Preparation of low viscosity component: PET foam with a viscosity of 0.55 dL / g is fed into a single screw extruder, the temperature is set to 260℃, and the second component masterbatch is obtained after atmospheric pressure melt extrusion granulation.

[0139] S7. The first component masterbatch and the second component masterbatch obtained in steps S5 and S6 are fed into a twin-screw spinning machine, melted and metered respectively, and then spun into nascent fibers through double "C" type spinnerets.

[0140] S8. The nascent fibers obtained in step S7 are stretched, crimped, cut, and shaped. The stretching ratio is 1.88, and the heat setting temperature is 125℃ to obtain functional parallel composite recycled polyester staple fibers.

[0141] Comparative Example 1

[0142] S1. Preparation of PS microspheres: 0.5 mol of PVP and 1 mol of AIBA were added to deionized water while stirring. Then, 0.5 mol of styrene monomer was added dropwise to the above solution. The mixture was heated to 70°C and kept at that temperature for 24 h. The mixture was washed with ethanol and water, centrifuged, and then vacuum dried at 50°C for 12 h to obtain PS microspheres.

[0143] S2. Preparation of PS / SiO2 particles: Take 10g of PS microspheres synthesized in step S1 and disperse them in a mixture of 150g of ethanol and deionized water (volume ratio of ethanol to deionized water is 4:1). Sonicate for 45min to obtain PS dispersion. Add ammonia to the dispersion to adjust the pH to 9, then slowly add 30mL of TEOS and stir continuously at 40℃ for 5h to allow SiO2 to grow on the surface of PS microspheres and form PS / SiO2 particles.

[0144] S3. Preparation of hollow SiO2: The PS / SiO2 particles synthesized in step S2 are placed in a muffle furnace and heated to 550°C at a rate of 2°C / min. The calcination is carried out for 4 hours to remove the PS particles and obtain hollow SiO2.

[0145] S4. Preparation of high-viscosity component: The hollow SiO2 obtained in step S3 is mixed with PET foam with a viscosity of 0.55 dL / g (the content of quaternary ammonium salt modified hollow SiO2 accounts for 3%). The mixing time is 15 min and the mixing speed is 1000 rpm. The premix is ​​fed into a twin-screw extruder. The temperatures of each section of the twin-screw extruder are: Zone I 255℃, Zone II 260℃, Zone III 265℃, Zone IV 270℃, and the die head temperature is 265℃. The melt is extruded, water-cooled, and pelletized to obtain the first component masterbatch. Its viscosity is tested to be increased to 0.74 dL / g.

[0146] S5. Preparation of low viscosity component: PET foam with a viscosity of 0.55 dL / g is fed into a single screw extruder, the temperature is set to 260℃, and the second component masterbatch is obtained after atmospheric pressure melt extrusion granulation.

[0147] S6. The first component masterbatch and the second component masterbatch obtained in steps S4 and S5 are fed into a twin-screw spinning machine, melted and metered respectively, and then spun into nascent fibers through double "C" type spinnerets.

[0148] S7. The nascent fibers obtained in step S6 are stretched, crimped, cut, and shaped. The stretching ratio is 1.8, and the heat setting temperature is 120℃ to obtain functional parallel composite recycled polyester staple fibers.

[0149] Comparative Example 2

[0150] S1. Preparation of nano-SiO2 particles: Take 150g of a mixture of ethanol and deionized water (volume ratio of ethanol to deionized water is 4:1), add ammonia water dropwise to adjust the pH to 9, then slowly add 30mL of TEOS, and stir continuously at 40℃ for 5h. Centrifuge the resulting liquid and wash it 4 times with anhydrous ethanol, then freeze dry to obtain nano-SiO2 particles.

[0151] S2. Modified SiO2: Take 10g of SiO2 particles obtained in step S1 and disperse them in 200g of anhydrous ethanol. Sonicate for 45min, then add 2g of cetyltrimethylammonium bromide and heat to 80℃ for 7h. After the reaction is completed, centrifuge to obtain the precipitate, wash it 4 times with anhydrous ethanol, and vacuum dry it at 75℃ for 18h to obtain quaternary ammonium salt modified SiO2.

[0152] S3. Preparation of high-viscosity component: The SiO2 particles obtained in step S2 are mixed with PET foam with a viscosity of 0.55 dL / g (quaternary ammonium salt modified SiO2 content accounts for 3%). The mixing time is 15 min and the mixing speed is 1000 rpm. The premix is ​​fed into a twin-screw extruder. The temperatures of each section of the twin-screw extruder are: Zone I 255℃, Zone II 260℃, Zone III 265℃, Zone IV 270℃, and the die head temperature is 265℃. The melt is extruded, water-cooled, and pelletized to obtain the first component masterbatch. Its viscosity is tested to be increased to 0.67 dL / g.

[0153] S4. Preparation of low-viscosity component: PET foam with a viscosity of 0.55 dL / g is fed into a single screw extruder, the temperature is set to 260℃, and the second component masterbatch is obtained after atmospheric pressure melt extrusion granulation.

[0154] S5. The first component masterbatch and the second component masterbatch obtained in steps S3 and S4 are fed into a twin-screw spinning machine, melted and metered respectively, and then spun into nascent fibers through double "C" type spinnerets.

[0155] S6. The nascent fibers obtained in step S5 are stretched, crimped, cut, and shaped. The stretching ratio is 1.8, and the heat setting temperature is 120℃ to obtain functional parallel composite recycled polyester staple fibers.

[0156] Performance Evaluation

[0157] Figure 1 The image shows an electron microscope image of the PS microspheres prepared in Example 1, with a diameter between 150 and 300 nm. The functional side-by-side composite recycled polyester staple fibers prepared in Examples 1-6 and Comparative Examples 1-2 were tested for visible light reflectance, antibacterial rate, and crimp rate. The results are shown in Table 1.

[0158] Table 1. Visible light reflectance, antibacterial rate, and crimp rate tests of the functional side-by-side composite recycled polyester staple fibers prepared in Examples 1-6 and Comparative Examples 1-2.

[0159] serial number Visible light reflectance (%) Escherichia coli inhibition rate (%) Curl rate (%) Example 1 93.3 99.6 19.4 Example 2 90.7 99.1 19.6 Example 3 91.6 99.0 21.2 Example 4 94.8 98.8 20.7 Example 5 92.9 98.9 19.9 Example 6 93.7 99.4 20.8 Comparative Example 1 89.4 62.1 18.5 Comparative Example 2 76.8 98.2 17.2

[0160] Table 1 shows that the functional side-by-side composite recycled polyester staple fibers prepared in Examples 1-6 have higher visible light reflectance and better antibacterial effect against Escherichia coli (higher antibacterial rate) compared to Comparative Examples 1-2. This is because the quaternary ammonium salt loaded on hollow SiO2 can significantly improve the antibacterial properties of the fiber, and the porous structure of hollow SiO2 can improve the visible light reflectance of the fiber. This indicates that the recycled fibers prepared by the method described in this invention have radiation cooling potential and excellent Escherichia coli inhibition effect, and also have a better crimp rate.

[0161] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a side-by-side composite recycled polyester fiber, characterized in that, Includes the following steps: (1) Polyvinylpyrrolidone, 2,2′-azobisisobutylamidine dihydrochloride, styrene and water were mixed and reacted to obtain polystyrene microspheres; (2) Mix polystyrene microspheres, silica precursor and first solvent and react them. Control the pH of the reaction system to 9-10 to form SiO2 particles on the surface of polystyrene microspheres to obtain PS / SiO2 particles. (3) The PS / SiO2 particles are calcined to obtain hollow SiO2; (4) The hollow SiO2, quaternary ammonium salt surfactant and second solvent are mixed and reacted to obtain quaternary ammonium salt modified hollow SiO2, which is then melt-blended with recycled polyester fiber foam to obtain the first masterbatch. (5) The second masterbatch obtained by melt extrusion granulation of recycled polyester fiber foam is mixed and melted with the first masterbatch, and then nascent fiber is obtained by parallel composite spinning; (6) The nascent fibers are stretched, curled, cut and shaped in sequence to obtain the parallel composite recycled polyester fibers.

2. The preparation method according to claim 1, characterized in that, The reaction temperature in step (1) is 60℃-80℃; In step (1), the molar ratio of polyvinylpyrrolidone and 2,2′-azobisisobutylamidine dihydrochloride is (0.5-1):

1.

3. The preparation method according to claim 1, characterized in that, The reaction temperature in step (2) is 40℃-50℃; In step (2), the silica precursor is selected from tetraethyl orthosilicate or methyl orthosilicate; The mass ratio of the silica precursor to the polystyrene microspheres is (2-4):

1.

4. The preparation method according to claim 1, characterized in that, The calcination temperature in step (3) is 500℃-650℃; The heating rate for calcination is 2-5℃ / min.

5. The preparation method according to claim 1, characterized in that, The reaction temperature in step (4) is 70℃-90℃; The quaternary ammonium salt surfactant in step (4) is selected from one or more of hexadecyltrimethylammonium bromide, dodecyltrimethylammonium chloride, and octadecyltrimethylammonium bromide; The mass of the quaternary ammonium salt surfactant is 15%-30% of the hollow SiO2.

6. The preparation method according to claim 5, characterized in that, In step (4), the mass of the quaternary ammonium salt modified hollow SiO2 in the first masterbatch is 3%-5% of the recycled polyester fiber foam. The intrinsic viscosity of the masterbatch is 0.7-0.75 dL / g; The viscosity of the recycled polyester fiber foam is 0.5-0.6 dL / g.

7. The preparation method according to claim 1, characterized in that, In step (2), the mass ratio of polystyrene microspheres to the first solvent is 1:(10-20). The first solvent is selected from a mixture of an alcohol solvent and water; The volume ratio of the alcohol solvent to water is (3-4):1; The alcohol solvent is selected from ethanol, methanol, or isopropanol; In step (4), the second solvent is selected from anhydrous ethanol or anhydrous methanol.

8. The preparation method according to claim 1, characterized in that, In step (5), the spinneret of the parallel composite spinning is double "C" shaped; The spinning box temperature for the parallel composite spinning is 250℃-260℃; The viscosity of the recycled polyester fiber foam in step (5) is 0.5-0.6 dL / g; The temperature of melt extrusion granulation in step (5) is 250℃-270℃.

9. The preparation method according to claim 8, characterized in that, The stretching ratio in step (6) is 1.5-2.2; The temperature for the shaping process is 110℃-140℃.

10. A side-by-side composite recycled polyester fiber, characterized in that, Prepared by the preparation method according to any one of claims 1-9; The visible light reflectance of the parallel-type composite recycled polyester fiber is 90%-95%; The Escherichia coli inhibition rate of the parallel-type composite recycled polyester fiber is 98%-99.6%; The crimp rate of the parallel composite recycled polyester fiber is 19%-22%.

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