Flexible PET crimped fiber and preparation method thereof

Abstract

The invention provides a flexible PET crimped fiber and a preparation method thereof, and the flexible PET crimped fiber can be prepared by reacting polyethylene glycol, waste PET bottle chips or low-melting-point polyester with PET chips, a chain extender, an antioxidant and a stabilizer, extruding and spinning, and then carrying out hot crimp deformation treatment. The PET fiber overcomes the performance defect that the PET fiber is difficult to deform due to high molecular chain rigidity, and can be widely applied to the fields of wigs, carpets, wool-like products, toys, home textiles and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical fiber preparation, and particularly relates to a flexible PET crimped fiber and a preparation method thereof. Background Art

[0002] PET (polyethylene terephthalate) has a rigid benzene ring structure and a relatively short flexible unit CH 2 CH 2 O in the molecular chain, so the molecular chain has a large rigidity and is characterized by high strength and high modulus; therefore, PET fibers have poor flexibility, a hard hand feeling, and are not easy to bend and deform; PBT (polybutylene terephthalate) has a molecular chain structure similar to that of PET and has a benzene ring structure, but its flexible unit is CH 2 CH 2 CH 2 CH 2 O; the flexible chain component is longer than that of PET, so PBT has higher flexibility and is easy to bend and deform; currently, the preparation of PET crimped fibers mainly uses the bicomponent spinning technology, using PE (polyethylene), PBT and PTT (polytrimethylene terephthalate) with higher flexibility as the side-by-side components to prepare composite fibers, and then performing heat crimping deformation treatment through the difference in the thermal shrinkage rate of the two components; however, the bicomponent spinning technology is relatively complex, has a high investment, and the introduction of the second component will greatly reduce the mechanical properties and heat resistance of PET fibers, and its application is subject to certain limitations; therefore, it is very necessary to provide a simple and feasible technical solution to solve the problems of low flexibility and difficult crimping deformation of PET fibers while maintaining the performance of PET fibers. Summary of the Invention

[0003] The present invention provides a flexible PET crimped fiber and a preparation method thereof, which solve the problem that PET fibers are rigid and not easy to deform, can effectively improve the flexibility of PET fibers, and provide a new solution for the rapid crimping of PET.

[0004] The technical solution of the present invention is realized as follows: a flexible PET crimped fiber and a preparation method thereof, comprising the following components in parts by mass: polymer A: 10-40 parts; PET chips: 50-89 parts; chain extender: 0-5 parts; antioxidant: 0.3-2 parts; stabilizer: 0.5-3 parts; the preparation steps are as follows: 1. Add polymer A, PET chips, chain extender, antioxidant and stabilizer into a high-speed mixer for mixing, and then send them into a screw spinning machine for melt reaction extrusion spinning; 2. After the fiber is cooled and wound up, it is subjected to stretching and setting and then heated and deformed and crimped. The finally obtained fiber has a strength of 2.1-3.5 cN / dtex, a modulus of less than 50 cN / dtex, a linear density of 50-80 dtex, and a crimp ratio of 10-32%, and can be used in fields such as wigs, carpets, wool-like products, toys, and home textiles.

[0005] The described polymer A is at least one of polyethylene glycol (PEG) with a molecular weight of 3000 - 50000, waste PET flakes with a viscosity of 0.3 - 0.6 dL / g, and low melting point polyester with a melting point of 130 - 220 °C; the chain extender is at least one of 1,4 - butanediol diglycidyl ether, triphenyl phosphite, hexamethylene diisocyanate, diphenylmethane - 4,4'-diisocyanate, bisoxazoline, bisoxazolidone, bisbenzoxazine, and bisdihydrooxazine; the antioxidant is at least one of antioxidant 1010, antioxidant 1024, antioxidant 1076, antioxidant 1098, and antioxidant 3114; the stabilizer is at least one of nano - zinc oxide, nano - titanium dioxide, nano - barium titanate, and nano - copper oxide.

[0006] The high - speed mixer has a rotation speed of 1000 - 20000 rpm / min and a mixing time of 2 - 5 min; the compression section of the screw extruder is equipped with a vacuum extraction port, the vacuum degree is 0.1 - 80 KPa, the melting reaction temperature is 240 - 270 °C, and the reaction time is 2 - 5 min; the spinning temperature is 265 - 295 °C, and the spinning speed is 400 - 900 m / min; the fiber cooling is carried out by ring blowing with cold air at 20 - 23 °C, 30 - 50 cm below the spinneret, the blowing length is 30 - 100 cm, and the wind speed is 2.2 - 3.6 m / s; the drawing and setting temperature is 78 - 90 °C, and the drawing ratio is 1.5 - 2.5 times; the heating and crimping deformation temperature has two sections, the temperature is 90 - 120 °C and the second section is at least 10 °C higher than the first section, and the heating time for each section is 5 - 20 s.

[0007] The present invention has the following beneficial effects: 1. Since the molecular weight of waste PET bottle material is relatively low and the molecular weight distribution is wide, by carrying out transesterification reaction with conventional PET in a screw extruder, it can be plasticized with PET at the molecular level, reducing the crystallization performance and glass transition temperature of PET and enhancing the flow performance, which is beneficial to the improvement of its flexibility. 2. By carrying out chain - extension reaction with PEG with a molecular weight of 3000 - 50000 and conventional PET in a screw extruder, the length of the flexible units of the PET molecular chain can be effectively increased, the flexibility and hygroscopicity of the PET molecular chain can be greatly improved, and then the flexibility of the fiber can be effectively improved, the melting point can be slightly decreased, and excellent hygroscopicity and antistatic properties can be given. 3. The low melting point polyester has good flexibility and is more sensitive to heat. By carrying out transesterification reaction with conventional PET in a screw extruder, it can be plasticized with PET at the molecular level. While improving the fiber flexibility, it can also enhance the difference in heat sensitivity of PET fibers and reduce the melting point of PET, which can significantly improve the fiber crimping performance. 4. In the present invention, molecular-level composite modification can be achieved by using waste PET bottle materials, polyethylene glycol, and low-melting polyester in a screw extruder with a chain extender. Then, high-flexibility PET crimped fibers can be obtained through direct spinning, stretching and setting, and two-stage thermal crimping deformation treatment, which has the advantages of simple process flow, easy operation, and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0009] Figure 1 It is the infrared spectrogram of the PET fiber in Example 1.

[0010] Figure 2 It is the thermogravimetric curve of the PET fibers in Examples 1-3.

[0011] Figure 3 It is the optical microscope image of the PET fiber in Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0012] The following will clearly and completely describe the technical solutions of the present invention in combination with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention. Example 1

[0013] As Figure 1 、 Figure 2 、 Figure 3 , 40 parts of waste PET bottle chips, 55 parts of PET chips, 0.3 part of 1,4-butanediol diglycidyl ether, 2 parts of antioxidant 1010, and 2.7 parts of nano-titanium dioxide are mixed in a high-speed mixer for 3 minutes (rotation speed 5000 rpm / min), and then sent to a screw extruder for reactive extrusion and spinning. The reaction temperature is 255 °C, the reaction time is 3 min, the spinning temperature is 275 °C, and the spinning speed is 450 m / min; the fiber is cooled by ring blowing with 20 °C cold air 30 cm below the spinneret, the blowing length is 50 cm, and the wind speed is 2.2 m / s; the stretching and setting temperature is 78 °C, the stretching ratio is 2.2 times, the temperature of the first stage of thermal crimping deformation is 90 °C, the temperature of the second stage is 105 °C, and the deformation time is 10 s for each stage, then high-flexibility crimped PET fibers can be obtained. Example 2

[0014] Mix 10 parts of PEG with a molecular weight of 50,000, 82 parts of PET chips, 3 parts of diphenylmethane-4,4'-diisocyanate, 2.1 parts of antioxidant 1076, and 2.9 parts of nano-copper oxide in a high-speed mixer for 2 minutes (rotation speed 10,000 rpm / min), then feed it into a screw extruder for reactive extrusion and spinning. The reaction temperature is 265 °C, the reaction time is 4 min, the spinning temperature is 260 °C, and the spinning speed is 700 m / min; the fiber is cooled by blowing 20 °C cold air in a circular pattern 30 cm below the spinneret, the blowing length is 80 cm, and the wind speed is 2.5 m / s; the drawing and setting temperature is 82 °C, the drawing ratio is 1.5 times, the temperature of the first stage of thermal crimping deformation is 100 °C, the temperature of the second stage is 120 °C, and the deformation time is 8 s for both, then high-flexibility crimped PET fibers can be obtained. Example 3

[0015] Mix 32 parts of low-melting polyester with a melting point of 220 °C, 65 parts of PET chips, 1.5 parts of antioxidant 1098, and 1.5 parts of nano-barium titanate in a high-speed mixer for 3 minutes (rotation speed 15,000 rpm / min), then feed it into a screw extruder for reactive extrusion and spinning. The reaction temperature is 260 °C, the reaction time is 5 min, the spinning temperature is 280 °C, and the spinning speed is 320 m / min; the fiber is cooled by blowing 22 °C cold air in a circular pattern 40 cm below the spinneret, the blowing length is 100 cm, and the wind speed is 2.2 m / s; the drawing and setting temperature is 87 °C, the drawing ratio is 1.8 times, the temperature of the first stage of thermal crimping deformation is 110 °C, the temperature of the second stage is 120 °C, and the deformation time is 20 s for both, then high-flexibility crimped PET fibers can be obtained. Example 4

[0016] Mix 18 parts of low-melting polyester with a melting point of 150 °C, 75 parts of PET chips, 3 parts of bisoxazoline, 3 parts of antioxidant 1076, and 1 part of nano-zinc oxide in a high-speed mixer for 5 minutes (rotation speed 1000 rpm / min), then feed it into a screw extruder for reactive extrusion and spinning. The reaction temperature is 255 °C, the reaction time is 3 min, the spinning temperature is 270 °C, and the spinning speed is 800 m / min; the fiber is cooled by blowing 23 °C cold air in a circular pattern 50 cm below the spinneret, the blowing length is 50 cm, and the wind speed is 3.6 m / s; the drawing and setting temperature is 83 °C, the drawing ratio is 1.5 times, the temperature of the first stage of thermal crimping deformation is 95 °C, the temperature of the second stage is 105 °C, and the deformation times are 10 s and 20 s respectively, then high-flexibility crimped PET fibers can be obtained. Example 5

[0017] Mix 12 parts of PEG with a molecular weight of 3000, 80 parts of PET chips, 5 parts of hexamethylene diisocyanate, 2 parts of antioxidant 1024, and 1 part of nano-zinc oxide in a high-speed mixer for 4 minutes (rotation speed 8000 rpm / min), then feed it into a screw extruder for reactive extrusion and spinning. The reaction temperature is 245 °C, the reaction time is 3 min, the spinning temperature is 263 °C, and the spinning speed is 600 m / min; the fiber is cooled by blowing 23 °C cold air in a circular pattern 40 cm below the spinneret, the blowing length is 40 cm, and the wind speed is 3.0 m / s; the stretching and setting temperature is 80 °C, the stretching ratio is 1.7 times, the temperature of the first stage of thermal crimping deformation is 95 °C, the temperature of the second stage is 115 °C, and the deformation time is 10 s for both, then high-flexibility crimped PET fibers can be obtained. Example 6

[0018] Mix 10 parts of low-melting polyester with a melting point of 160 °C, 86 parts of PET chips, 1 part of triphenyl phosphite, 2 parts of antioxidant 3114, and 1 part of nano-titanium dioxide in a high-speed mixer for 2 minutes (rotation speed 12000 rpm / min), then feed it into a screw extruder for reactive extrusion and spinning. The reaction temperature is 250 °C, the reaction time is 2.5 min, the spinning temperature is 260 °C, and the spinning speed is 400 m / min; the fiber is cooled by blowing 20 °C cold air in a circular pattern 30 cm below the spinneret, the blowing length is 50 cm, and the wind speed is 3.6 m / s; the stretching and setting temperature is 85 °C, the stretching ratio is 2 times, the temperature of the first stage of thermal crimping deformation is 90 °C, the temperature of the second stage is 100 °C, and the deformation time is 20 s for both, then high-flexibility crimped PET fibers can be obtained. Example 7

[0019] Mix 10 parts of waste PET bottle chips, 85 parts of PET chips, 2 parts of bisoxazolone, 2 parts of antioxidant 1010, and 1 part of nano-zinc oxide in a high-speed mixer for 4 minutes (rotation speed 8000 rpm / min), then feed it into a screw extruder for reactive extrusion and spinning. The reaction temperature is 260 °C, the reaction time is 2 min, the spinning temperature is 280 °C, and the spinning speed is 800 m / min; the fiber is cooled by blowing 23 °C cold air in a circular pattern 50 cm below the spinneret, the blowing length is 30 cm, and the wind speed is 2.8 m / s; the stretching and setting temperature is 85 °C, the stretching ratio is 2.4 times, the temperature of the first stage of thermal crimping deformation is 92 °C, the temperature of the second stage is 110 °C, and the deformation times are 10 s and 20 s respectively, then high-flexibility crimped PET fibers can be obtained. Example 8

[0020] Mix 30 parts of waste PET bottle chips, 65 parts of PET chips, 1.5 parts of bisbenzoxazine, 1.5 parts of antioxidant 1098, and 2 parts of barium titanate nanowhisker in a high-speed mixer for 3 minutes (rotation speed 20,000 rpm / min), then feed it into a screw extruder for reactive extrusion and spinning. The reaction temperature is 240 °C, the reaction time is 3 min, the spinning temperature is 265 °C, and the spinning speed is 500 m / min. The fiber is cooled by blowing air at 23 °C in a circular pattern 40 cm below the spinneret, the blowing length is 80 cm, and the wind speed is 2.5 m / s. The drawing and setting temperature is 85 °C, the drawing ratio is 2.5 times, the temperature of the first stage of thermal crimping deformation is 100 °C, the temperature of the second stage is 120 °C, and the deformation time is 15 s for both stages, then high-flexibility crimped PET fibers can be obtained. Example 9

[0021] Mix 40 parts of PEG with a molecular weight of 30,000, 55 parts of PET chips, 3 parts of bisoxazoline, 1 part of antioxidant 1024, and 1 part of zinc oxide nanowhisker in a high-speed mixer for 4 minutes (rotation speed 8,000 rpm / min), then feed it into a screw extruder for reactive extrusion and spinning. The reaction temperature is 245 °C, the reaction time is 3 min, the spinning temperature is 263 °C, and the spinning speed is 300 m / min. The fiber is cooled by blowing air at 23 °C in a circular pattern 40 cm below the spinneret, the blowing length is 40 cm, and the wind speed is 3.0 m / s. The drawing and setting temperature is 80 °C, the drawing ratio is 1.7 times, the temperature of the first stage of thermal crimping deformation is 95 °C, the temperature of the second stage is 120 °C, and the deformation time is 8 s for both stages, then high-flexibility crimped PET fibers can be obtained.

Claims

1. A flexible PET curly fiber and a preparation method thereof, characterized in that: The invention comprises the following components in parts by weight: polymer A: 10-40 parts; PET slices: 50-89 parts; chain extender: 0-5 parts; antioxidant: 0.3-2 parts; stabilizer: 0.5-3 parts; the preparation steps are as follows:

1. polymer A, PET slices, chain extender, antioxidant and stabilizer are added into a high-speed mixer for mixing, and then sent into a screw spinning machine for melt reaction extrusion spinning; 2. after the fiber is cooled and rolled up, it is stretched and shaped, and then heated, deformed and curled. The final fiber has a strength of 2.1-3.5 cN / dtex, a modulus of less than 50 cN / dtex, a linear density of 50-80 dtex, and a curling rate of 10-32%. The fiber can be used in wigs, carpets, imitation wool products, toys, home textiles and other fields.

2. The flexible PET curly fiber and the preparation method thereof according to claim 1, characterized in that: The polymer A is at least one of polyethylene glycol (PEG) with a molecular weight of 3000-50000, waste PET bottle flakes with a viscosity of 0.3-0.6 dL / g and low-melting polyester with a melting point of 130-220°C; the chain extender is at least one of 1-4-butanediol diglycidyl ether, triphenyl phosphite, hexamethylene diisocyanate, diphenylmethane-4-4'-diisocyanate, bisoxazoline, bisoxazolone, bisbenzoxazine and bisdihydroxazine; the antioxidant is at least one of antioxidant 1010, antioxidant 1024, antioxidant 1076, antioxidant 1098 and antioxidant 3114; the stabilizer is at least one of nano zinc oxide, nano titanium dioxide, nano barium titanate and nano copper oxide.

3. The flexible PET curly fiber and the preparation method thereof according to claim 1, characterized in that: The speed of the high-speed mixer is 1000-20000rpm / min, and the mixing time is 2-5min; the compression section of the screw extruder is provided with a vacuum port, the vacuum degree is 0.1-80KPa, the melt reaction temperature is 240-270℃, and the reaction time is 2-5min; the spinning temperature is 265-295℃, and the spinning speed is 400-900m / min; the fiber cooling adopts 20-23℃ cold wind to carry out ring blowing at 30-50cm below the spinneret, the blowing length is 30-100cm, and the wind speed is 2.2-3.6m / s; the stretching setting temperature is 78-90℃, and the stretching multiple is 1.5-2.5 times; the heating curling deformation temperature is two stages, the temperature is 90-120℃ and the second stage is at least 10℃ higher than the first stage, and the heating time of each stage is 5-20s.

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