Preparation method of RPET (Resin Polyethylene Terephthalate) fiber and RPET fiber
Through efficient recycling and modification of waste PET resources, the problem of high dependence on oil resources in the production process of traditional PET fibers is solved, and the versatility and wide application of RPET fibers are achieved.
Patent Information
- Application Number
- CN202411794121.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-09
- Publication Date
- 2025-03-04
AI Technical Summary
The high dependence on petroleum resources in the production process of traditional PET fibers leads to high production costs. At the same time, the modification and treatment of waste resources are poor, which limits the application scope of RPET fibers.
By collecting and cleaning the discarded PET bottles and films, using ultrasonic cleaning equipment and crushers, they are processed into uniform small pieces, and then melting and preparing in a twin-screw extruder, nano-scale inorganic particles and organic functional additives are added, and deep entanglement additives and RPET molecular chains are enhanced through high-speed stirring and refining strengthening technology, deep entanglement additives and RPET molecular chains are enhanced.
It realizes efficient recycling and modification of waste PET resources, reduces dependence on oil resources, reduces production costs, and gives RPET fiber special functions such as antibacterial, ultraviolet, and conductivity, broadens its application scope.
Smart Images
Figure CN119553386A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of textiles, in particular to a preparation method of RPET fiber and the RPET fiber. Background Art
[0002] In today's textile field, polyethylene terephthalate (PET) fiber has become one of the most widely used mainstream textile raw materials due to its excellent physical and chemical properties such as high strength, wear resistance, and good chemical stability. From daily clothing and accessories to industrial textiles, PET fiber is everywhere. However, traditional PET fiber relies on petroleum resources to synthesize through complex processes. As a non-renewable energy source, the large-scale consumption of petroleum not only makes the production cost affected by the fluctuation of raw material prices for a long time, but also highlights the concerns about resource sustainability. With the popularization of environmental protection concepts and the rising demand for resource recycling, the recycling of waste PET bottles, PET films, etc. has become a hot research direction. Remaking such waste resources into RPET raw materials and then processing them into fibers can theoretically kill two birds with one stone, reducing dependence on original petroleum resources and resolving the problem of waste disposal.
[0003] The existing RPET fiber products made by recycling and reuse processes are difficult to remove impurities and have damaged molecular chains. Their strength and toughness are far inferior to those of virgin PET fibers. They have poor color fastness and a rough feel. They cannot meet the stringent requirements of sports equipment for stretch recovery, outdoor textiles for resistance to UV rays, and medical and sanitary products for antibacterial and antimicrobial properties. In addition, the waste resource modification technology is immature, additives are unevenly dispersed, and chemical bonds are unstable, resulting in a single fiber function and limited application scenarios. It is difficult to replace virgin PET fibers on a large scale to enter the high-end market, so innovation and improvement are urgently needed. Summary of the invention
[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.
[0005] In view of the above and / or existing methods for preparing RPET fibers and the problems existing in RPET fibers, the present invention is proposed.
[0006] Therefore, the problem to be solved by the present invention is that in the traditional PET fiber production process, there is a high dependence on petroleum resources, resulting in high production costs, and the modification treatment effect of waste resources is not good, which limits the application scope of RPET fiber.
[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: a preparation method of RPET fiber and RPET fiber, comprising the following steps: step a: collection link: organize a professional recycling team or establish cooperation with local waste recycling stations, garbage treatment centers, and related factories to widely collect discarded PET bottles and PET films, first arrange manual preliminary screening, and use the naked eye and simple tools to remove the obvious non-PET material debris mixed in, and classify and organize the discarded PET resources after preliminary cleaning; step b: cleaning process: put the discarded PET materials after coarse screening into a special ultrasonic cleaning equipment in batches, inject a mixed solution of special detergent and water prepared in a specific ratio into the cleaning tank, turn on the ultrasonic device, and then use clean water Repeat rinsing for 3-5 times until the pH and turbidity of the discharged water after cleaning meet the environmental protection emission standards, ensuring that the surface of the washed PET material is clean and free of impurities; Step c: Crushing: Put the washed and dried PET material into the crusher, adjust the distance between the crusher cutters according to the feeding requirements of the subsequent melting equipment, and crush the PET into uniform small pieces with a side length of about 3-5 mm; Step d: Melting preparation: The crushed PET small pieces are transported to the hopper of the twin-screw extruder with precise temperature control and pressure regulation functions, and appropriate pressure is applied at the same time to ensure that the material is fully melted and plasticized under the synergistic effect of screw shearing, extrusion and heat conduction, and then extruded through the die to produce RPET raw materials with uniform texture and high purity, which are then air-cooled or water-cooled after extrusion. The formula is quickly formed into strips and blocks for storage and standby; Step e: Adding additives: According to the expected functional requirements of the RPET fiber, accurately weigh the corresponding nano-scale inorganic particles and organic functional additives, and put the weighed additives and the pretreated RPET raw materials into the high-speed mixer silo; Step f: Premixing operation: Start the high-speed mixer, and at the same time, pass steam or heat-conducting oil into the silo jacket to heat the material temperature gradually to 100-120°C, so that the additives are initially and evenly dispersed between the RPET raw material particles during the heating and stirring process to form a preliminary mixed material; Step g: Internal mixing and strengthening: Transfer the premixed material to the internal mixer, and use the strong shearing, extrusion and flipping of the rotor to make the additives deeply entangled with the RPET molecular chain. , chemical bonding reaction occurs, the molecular chain breakage and defects in the early processing of the raw materials are repaired, the comprehensive performance of the RPET raw materials is improved, and the modified high-quality RPET raw materials are obtained. After the internal mixing is completed, they are discharged through the discharge port and stored after natural cooling to room temperature; Step h: Spinning process selection: According to the actual use of the product, performance requirements and cost considerations, the melt spinning or solution spinning process is reasonably selected; Step i: Post-processing process: The primary fibers are stretched and heat-set, and the fibers are stretched by a multi-roller stretching device at a preset stretching ratio of 3-5 times. The tension is simultaneously controlled in an appropriate range during the stretching process to ensure that the fiber molecular chains are arranged in an axial orientation. Heat setting is carried out in a heat setting box, and the RPET fiber finished product with the required function can be obtained after setting.
[0008] As a preferred embodiment of the preparation method of the RPET fiber and the RPET fiber of the present invention, the ultrasonic device in the step b is set at a frequency of 20-50kHz, and ultrasonic cavitation is used in combination with mechanical stirring to separate pollutants such as oil, glue residue, and dust from the surface of the PET, and the cleaning time is controlled at 30-60 minutes.
[0009] As a preferred embodiment of the preparation method of RPET fiber and RPET fiber of the present invention, wherein: in the step d, the temperature of each heating zone of the extruder is set to be gradually increased from 250° C. to 280° C. in sequence, and the screw speed is adjusted to 80-120 rpm.
[0010] As a preferred embodiment of the preparation method of the RPET fiber and the RPET fiber of the present invention, the antibacterial agent in step e includes nano-silver and nano-titanium dioxide, the anti-radiation agent includes benzophenone and benzotriazole ultraviolet absorbers, and the antistatic agent includes conductive carbon black and conductive polymer.
[0011] As a preferred embodiment of the preparation method of the RPET fiber and the RPET fiber of the present invention, wherein: in the step f, the stirring paddle speed is set at 500-800 rpm, and the stirring time is controlled at 20-40 minutes.
[0012] As a preferred embodiment of the preparation method of RPET fiber and RPET fiber of the present invention, the internal mixer in step g adopts an "Ω" type rotor, the internal mixer chamber temperature is set at 150-180°C, the rotor speed is set at 30-60 rpm, and the internal mixer time is maintained for 30-60 minutes.
[0013] As a preparation method of the RPET fiber and a preferred embodiment of the RPET fiber described in the present invention, the melt spinning process in the step h is as follows: the modified RPET raw material is put into the hopper of the melt spinning equipment, the temperature of each heating zone of the spinning box is set to be accurately controlled at 260-290°C to ensure that the raw material is fully melted and maintains stable fluidity, and is quantitatively transported to the spinning assembly at a preset flow rate through a metering pump, and extruded into a thin stream of melt through a spinneret with a specific number of holes and apertures. Under the action of a side-blowing cooling device, cold air is used to cool and solidify the melt stream at a flow rate of 1-3 m / s and a temperature of 15-25°C to form nascent fibers.
[0014] As a preparation method of the RPET fiber and a preferred embodiment of the RPET fiber described in the present invention, the solution spinning process in the step h is as follows: a solvent with good solubility, low volatility and non-toxicity to RPET is selected, and the modified RPET raw material is dissolved in proportion to form a spinning solution, which is placed in a vacuum degassing device and degassed at a negative pressure of 80-100 kPa for 30-60 minutes to remove bubbles in the spinning solution and avoid spinning defects. After degassing, the spinning solution is transported to the spinneret for spinning via a metering pump, and a thin stream is ejected into a coagulation bath to coagulate and form primary fibers.
[0015] As a preferred embodiment of the preparation method of the RPET fiber and the RPET fiber of the present invention, the temperature of the heat setting box in the step i is set at 180-220° C. and the processing time is 10-30 seconds, so as to give the fiber good crystallinity and dimensional stability.
[0016] The RPET fiber prepared by the preparation method of RPET fiber comprises an RPET fiber main body, wherein the RPET fiber main body is divided into antibacterial RPET fiber, anti-ultraviolet RPET fiber and conductive RPET fiber, wherein the antibacterial RPET fiber is composed of 93% RPET basic raw material, 5% nano silver antibacterial agent, 1% quaternary ammonium salt organic antibacterial agent and 1% antistatic agent, the anti-ultraviolet RPET fiber is composed of 90% RPET basic raw material, 4% nano titanium dioxide, 4% benzotriazole ultraviolet absorber and 2% softener, and the conductive RPET fiber is composed of 89% RPET basic raw material, 7% conductive carbon black, 3% polythiophene conductive polymer and 1% antistatic agent.
[0017] The beneficial effects of the present invention are: utilizing waste PET resources, getting rid of dependence on high-priced petroleum raw materials, reducing costs, realizing waste recycling, reducing processing burdens, and using modification treatments, adding nanoparticles and additives, repairing molecular chains, and enhancing basic properties of strength, imparting special functions such as antibacterial, UV resistance, and electrical conductivity, broadening applications, customizing on demand, and producing diverse functional fibers to meet the needs of multiple fields and enhance added value and competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:
[0019] Figure 1 The invention discloses a method for preparing RPET fiber and a flow chart of RPET fiber. DETAILED DESCRIPTION
[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.
[0021] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.
[0022] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.
[0023] Example 1
[0024] Reference Figure 1, which is the first embodiment of the present invention, and provides a method for preparing RPET fiber and RPET fiber. The method for preparing RPET fiber includes the following steps: Step a: Collection link: Organize a professional recycling team or establish cooperation with waste recycling stations, garbage treatment centers, and related factories in various places to widely collect waste PET bottles and PET films, first arrange manual preliminary screening, and use the naked eye and simple tools to remove the obvious non-PET material debris mixed in, and classify and organize the waste PET resources after preliminary cleaning; Step b: Cleaning process: Put the waste PET materials after coarse screening into a special ultrasonic cleaning equipment in batches, and inject a certain proportion of the waste PET materials into the cleaning tank. Prepare a mixed solution of special detergent and water, turn on the ultrasonic device, and then rinse repeatedly with clean water for 3-5 times until the pH and turbidity of the discharged water after cleaning meet the environmental emission standards to ensure that the surface of the washed PET material is clean and free of impurities. The ultrasonic device is set at a frequency of 20-50kHz, and the ultrasonic cavitation effect is used in combination with mechanical stirring to separate pollutants such as oil, glue residue, and dust from the PET surface. The cleaning time is controlled at 30-60 minutes; Step c: Crushing: Put the washed and dried PET material into the crusher, adjust the distance between the crusher cutters according to the feeding requirements of the subsequent melting equipment, and crush the PET into uniform pieces with a side length of about 3-5 mm. Small pieces; Step d: Melting preparation: The crushed PET small pieces are conveyed to the hopper of a twin-screw extruder with precise temperature control and pressure regulation functions, and appropriate pressure is applied at the same time to ensure that the material is fully melted and plasticized under the synergistic effect of screw shearing, extrusion and heat conduction. After extrusion through the die, the RPET raw material with uniform texture and high purity is made. After extrusion, it is quickly shaped into strips and blocks by air cooling or water cooling for storage and standby. The temperature of each heating zone of the extruder is set to gradually increase from 250°C to 280°C, and the screw speed is adjusted to 80-120 rpm; Step e: Adding additives: According to the expected functional requirements of the preparation of RPET fiber, accurately weigh the corresponding nano-scale inorganic particles and organic Functional additives: weigh the additives and the pretreated RPET raw materials and put them into the silo of the high-speed mixer. The antibacterial additives include nano silver and nano titanium dioxide, the anti-radiation additives include benzophenone and benzotriazole ultraviolet absorbers, and the antistatic additives include conductive carbon black and conductive polymers. Step f: premixing operation: start the high-speed mixer, and at the same time, pass steam or heat transfer oil into the silo jacket to heat it, so that the material temperature gradually rises to 100-120°C, so that the additives are initially and evenly dispersed between the RPET raw material particles during the heating and stirring process to form a preliminary mixed material, set the stirring blade speed at 500-800 rpm, and control the stirring time at 20-40 minutes;Step g: Internal mixing and strengthening: The premixed material is transferred to the internal mixer. With the help of the strong shearing, extrusion and flipping of the rotor, the additives and the RPET molecular chains are deeply entangled and chemically bonded to repair the molecular chain breakage and defects in the early processing of the raw materials, improve the comprehensive performance of the RPET raw materials, and obtain the modified high-quality RPET raw materials. After the internal mixing is completed, it is discharged through the discharge port and stored after natural cooling to room temperature. The internal mixer adopts an "Ω" type rotor, and the internal mixing chamber temperature is set at 150-180℃ and the rotor speed is set at 30- 60 rpm, the mixing time is maintained for 30-60 minutes; Step h: Spinning process selection: According to the actual use of the product, performance requirements and cost considerations, the melt spinning or solution spinning process is reasonably selected. Melt spinning process: The modified RPET raw material is put into the hopper of the melt spinning equipment, and the temperature of each heating zone of the spinning box is set to be accurately controlled at 260-290℃ to ensure that the raw material is fully melted and maintains stable fluidity. It is quantitatively transported to the spinning assembly at a preset flow rate through a metering pump and extruded into fine particles through a spinneret with a specific number of holes and apertures. The liquid melt is cooled and solidified by cold air at a flow rate of 1-3 m / s and a temperature of 15-25°C under the action of the side-blowing cooling device to form primary fibers. Solution spinning process: select a solvent with good solubility, low volatility and non-toxicity for RPET, dissolve the modified RPET raw material in proportion to make a spinning solution, place it in a vacuum degassing device, degas for 30-60 minutes at a negative pressure of 80-100 kPa to remove bubbles in the spinning solution and avoid spinning defects. After degassing, the spinning solution is transported to the spinneret through a metering pump for spinning. The thin stream enters the coagulation bath and coagulates to form the primary fiber; Step i: Post-processing process: The primary fiber is stretched and heat-set, and the multi-roller stretching device is used to stretch the fiber according to the preset stretching ratio of 3-5 times. The tension is controlled in the appropriate range during the stretching process to ensure that the fiber molecular chain is oriented along the axial direction. Heat setting is carried out in a heat setting box with a set temperature of 180-220℃ and a processing time of 10-30 seconds to give the fiber good crystallinity and dimensional stability. After setting, the RPET fiber product with the required function can be obtained. ;
[0025] The RPET fiber prepared by the preparation method of RPET fiber comprises an RPET fiber main body, and the RPET fiber main body is divided into antibacterial RPET fiber, anti-ultraviolet RPET fiber and conductive RPET fiber. The antibacterial RPET fiber is composed of RPET basic raw material: 93%, nano silver antibacterial agent: 5%, quaternary ammonium salt organic antibacterial agent: 1% and antistatic agent: 1%, the anti-ultraviolet RPET fiber is composed of RPET basic raw material: 90%, nano titanium dioxide: 4%, benzotriazole ultraviolet absorber: 4% and softener: 2%, and the conductive RPET fiber is composed of RPET basic raw material: 89%, conductive carbon black: 7%, polythiophene conductive polymer: 3% and antistatic agent: 1%.
[0026] Example 2
[0027] Reference Figure 1 , which is the second embodiment of the present invention, and this embodiment is based on the previous embodiment.
[0028] Preparation of antibacterial RPET fibers for medical and sanitary bedding
[0029] Raw material pretreatment:
[0030] We have established close cooperation with local large hospitals, medical waste recycling companies and garbage sorting points in surrounding communities, and set up professional recycling teams to regularly collect discarded PET medical supplies, such as disposable PET infusion bottles, dialysis fluid packaging bags and other discarded PET film materials. We carefully sort them manually, remove the attached infusion tubes, paper labels, plastic bottle caps (mostly made of polypropylene) and metal sealing parts and other non-PET material debris, and preliminarily classify and store the screened discarded PET resources according to source and category.
[0031] Place the sorted waste PET materials in batches into a special cleaning tank for ultrasonic cleaning equipment, inject a mixed solution of environmentally friendly, PET-friendly detergent (the main ingredients include biodegradable surfactants and detergent aids) and water in a ratio of 1:10, turn on the ultrasonic device, set the frequency to 30kHz, and turn on the mechanical stirring paddle (stirring speed 50 rpm) at the same time. Use the cavitation effect generated by ultrasound and mechanical stirring to promote the peeling of oil, drug residues, dust and other pollutants from the PET surface. The cleaning time is maintained at 45 minutes. After cleaning, rinse with clean water 4 times, and the amount of water for each rinse is 1.5 times the volume of the cleaning tank until the pH of the discharged water is maintained between 6-8 and the turbidity is less than 5NTU, ensuring that the surface of the PET material is clean and free of impurities.
[0032] The washed and dried PET material is put into the jaw crusher. According to the size of the subsequent twin-screw extruder feed port (the maximum side length of the material is required to be no more than 4 mm), the crusher tool spacing is accurately adjusted to 3.5 mm to crush the PET into uniform small pieces for subsequent efficient melt processing.
[0033] The crushed PET pieces are transported to the hopper of a twin-screw extruder with precise temperature and pressure control functions through a conveyor belt. The temperatures of the heating zones from the hopper end to the head end of the extruder are set to 250°C, 260°C, 270°C, and 280°C respectively. The screw speed is stabilized at 100 rpm. At the same time, a pressure of 0.3-0.5MPa is applied inside the barrel to ensure that the material is fully melted and plasticized under the synergistic effect of shearing, extrusion and heat conduction of the screw. After being extruded through the head, RPET raw material strips with fine texture and high purity are formed, which are quickly shaped into strips and blocks by air cooling (air cooling temperature 20°C, wind speed 3 m / s), and collected and stored for later use.
[0034] Modification treatment:
[0035] In order to prepare the antibacterial RPET fiber, nano-silver antibacterial agent (average particle size 30 nanometers, purity 98%) and 2% nano-titanium dioxide antibacterial agent (anatase type, particle size 20 nanometers) were accurately weighed according to 3% of the weight of the RPET raw material, and the weighed antibacterial agent and 100 kg of pretreated RPET raw material were put into the silo of the high-speed mixer.
[0036] Start the high-speed mixer, set the stirring blade speed to 600 rpm, and introduce steam into the silo jacket for heating, so that the material temperature starts from room temperature and rises to 110°C at a heating rate of 2°C per minute. Continue stirring for 30 minutes to enable the antibacterial agent to be initially and evenly dispersed among the RPET raw material particles during the heating and stirring process to form a preliminary mixed material.
[0037] The premixed material is transferred to an internal mixer (using a "Z" type rotor), and the temperature of the internal mixer chamber is set at 160°C, the rotor speed is 40 rpm, and the internal mixer time is 40 minutes. With the help of the strong shearing, extrusion, and flipping effects of the rotor, the antibacterial agent and the RPET molecular chain are deeply entangled and chemically bonded, thereby repairing the molecular chain breakage and structural defects that may occur in the early processing of the raw materials, improving the comprehensive performance of the RPET raw materials, and obtaining modified high-quality RPET raw materials. After the internal mixer is completed, it is discharged through the discharge port and stored after natural cooling to room temperature.
[0038] Fiber preparation:
[0039] In view of the fact that medical bedding has certain requirements for fiber strength and production efficiency, and does not require special solubility, the melt spinning process is selected. The modified RPET raw material is put into the hopper of the melt spinning equipment, and the temperature of each heating zone of the spinning box is set to 260℃, 270℃, and 280℃ respectively to ensure that the raw material is fully melted and has stable fluidity.
[0040] It is quantitatively delivered to the spinning assembly at a preset flow rate by a metering pump, and extruded into a thin stream of melt through a spinneret with 300 circular holes (aperture 0.3 mm). Under the action of a side-blowing cooling device (cold air flow rate of 2 m / s, temperature 20°C), the melt stream is cooled and solidified to form primary fibers.
[0041] The nascent fibers are stretched at a 4-fold stretching ratio through a five-roll stretching device. During the stretching process, a tension sensor is used to monitor and control the tension in real time to maintain it at 0.8-1.2 cN / dtex to ensure that the fiber molecular chains are oriented along the axial direction. They are then treated in a heat setting box (set temperature 200°C) for 20 seconds to give the fibers good crystallinity and dimensional stability. Finally, they are made into RPET fiber products that meet the specifications and functional requirements of medical bedding products. They are woven into medical sheets, quilt covers and other products. The antibacterial rate has been tested to be over 98%, which can effectively inhibit the growth of common bacteria and ensure the hygiene of the medical environment.
[0042] Example 3
[0043] Reference Figure 1 , which is the third embodiment of the present invention, and is based on the first two embodiments.
[0044] Raw material pretreatment:
[0045] We have established cooperation with waste recycling stations, outdoor advertising production companies and beverage bottle recycling plants in various places to collect discarded PET beverage bottles, PET sheets for outdoor advertising and discarded awning PET films, etc. We manually screen and remove non-PET impurities such as metal frames, plastic tapes, paper labels, etc., and roughly classify them according to different sources and materials and store them in an orderly manner.
[0046] Put the waste PET materials after coarse screening into the ultrasonic cleaning equipment in batches, fill the cleaning tank with a mixed solution of environmentally friendly detergent (mainly containing surfactants and chelating agents) and water in a ratio of 1:8, turn on the ultrasonic device, set the frequency to 40kHz, and cooperate with mechanical stirring (stirring rate 60 rpm) to clean for 35 minutes with the help of ultrasonic cavitation to remove oil, dust, glue residues, etc. from the PET surface. After cleaning, rinse with clean water 3 times until the pH of the discharged water is between 6.5-7.5 and the turbidity is less than 3NTU to ensure that the PET material is clean.
[0047] The washed and dried PET material is put into the cone crusher. According to the feeding requirements of the subsequent melting equipment (the material side length is preferably 3-4 mm), the distance between the crusher cutters is adjusted to 3.2 mm to crush it into uniform small pieces for subsequent processing.
[0048] The crushed PET pieces are conveyed to the hopper of the twin-screw extruder. The temperatures of the heating zones of the extruder are set to 255°C, 265°C, 275°C and 280°C respectively. The screw speed is maintained at 90 rpm and a pressure of 0.4-0.6MPa is applied to promote full melting and plasticization of the material. After being extruded through the die, the material is quickly shaped into strips and blocks of RPET raw materials by water cooling (water temperature 15°C, water flow rate 0.5 m / s) and stored for later use.
[0049] Modification treatment:
[0050] Based on the demand for preparing UV-resistant RPET fiber, 4% of the weight of RPET raw material was used as benzotriazole UV absorber (with an active ingredient content of 92%) and 3% of nano titanium dioxide (rutile type, with a particle size of 25 nanometers), and the two were put into the silo of a high-speed mixer together with 100 kg of pretreated RPET raw material.
[0051] Start the high-speed mixer, set the stirring blade speed to 700 rpm, and pass heat transfer oil into the silo jacket to heat the material temperature from room temperature to 105°C at a rate of 2.5°C per minute. Stir for 25 minutes to achieve preliminary uniform dispersion and form a premixed material.
[0052] The premixed materials were transferred to an internal mixer ("Ω" type rotor), the temperature of the internal mixer chamber was set to 170°C, the rotor speed was 50 rpm, and the internal mixer was performed for 50 minutes to allow the UV absorber, nano-titanium dioxide and RPET molecular chains to be deeply entangled and chemically bonded, repair molecular chain problems, and improve comprehensive performance. After the internal mixer was completed, the materials were cooled and stored.
[0053] Fiber preparation:
[0054] Considering the special requirements of outdoor leisure tent fabrics for fiber functions, the solution spinning process was selected. Hexafluoroisopropanol was selected as the solvent, and the modified RPET raw material was dissolved into a spinning solution at a ratio of 20% by mass of RPET in the solution. The solution was placed in a vacuum degassing device and degassed for 40 minutes under a negative pressure of 90kPa to remove the bubbles in the spinning solution.
[0055] After degassing, the spinning solution is transported to the spinneret through a metering pump for spinning, and a thin stream is ejected into a coagulation bath (the coagulation bath is prepared by mixing ethanol and water in a ratio of 7:3 to promote the precipitation and formation of RPET), and coagulated to obtain primary fibers.
[0056] The nascent fiber is stretched by a four-roll stretching device at a stretching ratio of 3.5 times. The tension is controlled at 0.7-1.1 cN / dtex during the stretching process. It is treated in a heat setting box (temperature 190°C) for 15 seconds to produce RPET fiber products that meet the specifications of outdoor tent fabrics. After being woven into tent fabrics, it is tested that the ultraviolet protection factor reaches UPF50+, which can effectively resist ultraviolet rays, extend the service life of the tent, and ensure comfort for outdoor use.
[0057] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.
Claims
1. A method for preparing RPET fiber, characterized in that: The following steps are involved: Step a: Collection: Organize a professional recycling team or establish cooperation with local waste recycling stations, garbage treatment centers, and related factories to widely collect waste PET bottles and PET films. First, arrange manual labor for preliminary screening. With the naked eye and simple tools, remove the obvious non-PET material debris mixed in, and classify and sort the waste PET resources after preliminary cleaning; Step b: Cleaning process: Place the waste PET materials after coarse screening in batches into a special ultrasonic cleaning device, inject a mixed solution of special detergent and water prepared in a specific ratio into the cleaning tank, turn on the ultrasonic device, and then rinse with clean water repeatedly for 3-5 times until the pH and turbidity of the discharged water after cleaning are detected to meet the environmental protection discharge standards, ensuring that the surface of the washed PET material is clean and free of impurities; Step c: Crushing: Put the washed and dried PET material into the crusher, adjust the distance between the crusher cutters according to the feeding requirements of the subsequent melting equipment, and crush the PET into uniform small pieces with a side length of about 3-5 mm; Step d: Melting preparation: The crushed PET pieces are conveyed to the hopper of a twin-screw extruder with precise temperature and pressure control functions, and appropriate pressure is applied to ensure that the material is fully melted and plasticized under the synergistic effect of screw shearing, extrusion and heat conduction. After extrusion through the die, the RPET raw material with uniform texture and high purity is produced. After extrusion, it is quickly shaped into strips and blocks by air cooling or water cooling for storage and standby use; Step e: Adding additives: According to the expected functional requirements of the RPET fiber, accurately weigh the corresponding nano-scale inorganic particles and organic functional additives, and put the weighed additives and the pretreated RPET raw materials into the high-speed mixer silo; Step f: premixing operation: start the high-speed mixer, and at the same time, pass steam or heat-conducting oil into the silo jacket to heat it, so that the material temperature gradually rises to 100-120°C, so that the additive is initially and evenly dispersed among the RPET raw material particles during the heating and stirring process to form a preliminary mixed material; Step g: Internal mixing and strengthening: the premixed material is transferred to the internal mixer, and the strong shearing, squeezing and turning action of the rotor is used to make the additives deeply entangled with the RPET molecular chain and produce a chemical bonding reaction, thereby repairing the molecular chain breakage and defects in the early processing of the raw material, improving the comprehensive performance of the RPET raw material, and obtaining the modified high-quality RPET raw material. After the internal mixing is completed, it is discharged through the discharge port and stored after naturally cooling to room temperature; Step h: Spinning process selection: According to the actual use of the product, performance requirements and cost considerations, reasonably select melt spinning or solution spinning process; Step i: Post-processing process: The nascent fibers are stretched and heat-set by a multi-roller stretching device at a preset stretching ratio of 3-5 times. The tension is simultaneously controlled within an appropriate range during the stretching process to ensure that the fiber molecular chains are oriented along the axial direction. Heat setting is performed in a heat setting box. After setting, the RPET fiber product with the desired function can be obtained.
2. The method for preparing RPET fiber according to claim 1, characterized in that: In step b, the frequency of the ultrasonic device is set at 20-50 kHz, and ultrasonic cavitation is used in combination with mechanical stirring to remove pollutants such as oil, glue residue, and dust from the surface of the PET, and the cleaning time is controlled at 30-60 minutes.
3. The method for preparing RPET fiber according to claim 1, characterized in that: In the step d, the temperature of each heating zone of the extruder is set to be gradually increased from 250° C. to 280° C., and the screw speed is adjusted to 80-120 rpm.
4. The method for preparing RPET fiber according to claim 1, characterized in that: In the step e, the antibacterial agent includes nano silver and nano titanium dioxide, the anti-radiation agent includes benzophenone and benzotriazole ultraviolet absorbers, and the antistatic agent includes conductive carbon black and conductive polymer.
5. The method for preparing RPET fiber according to claim 1, characterized in that: In the step f, the stirring blade speed is set at 500-800 rpm, and the stirring time is controlled at 20-40 minutes.
6. The method for preparing RPET fiber according to claim 1, characterized in that: In step g, the internal mixer adopts an "Ω" type rotor, the internal mixer chamber temperature is set at 150-180° C., the rotor speed is set at 30-60 rpm, and the internal mixer time is maintained at 30-60 minutes.
7. The method for preparing RPET fiber according to claim 1, characterized in that: The melt spinning process in step h is as follows: the modified RPET raw material is put into the hopper of the melt spinning equipment, the temperature of each heating zone of the spinning box is set to be accurately controlled at 260-290°C to ensure that the raw material is fully melted and maintains stable fluidity, and the raw material is quantitatively delivered to the spinning assembly at a preset flow rate through a metering pump, and extruded into a thin stream of melt through a spinneret with a specific number of holes and apertures. Under the action of a side-blowing cooling device, cold air is used at a flow rate of 1-3 m / s and a temperature of 15-25°C to cool and solidify the melt stream to form primary fibers.
8. The method for preparing RPET fiber according to claim 1, characterized in that: The solution spinning process in step h is as follows: a solvent with good solubility, low volatility and no toxicity to RPET is selected, and the modified RPET raw material is dissolved in proportion to form a spinning solution, which is placed in a vacuum degassing device and degassed at a negative pressure of 80-100 kPa for 30-60 minutes to remove bubbles in the spinning solution and avoid spinning defects. After degassing, the spinning solution is transported to the spinneret for spinning via a metering pump, and a thin stream is ejected into a coagulation bath to coagulate and form primary fibers.
9. The method for preparing RPET fiber according to claim 1, characterized in that: In the step i, the temperature of the heat setting box is set at 180-220° C. and the processing time is 10-30 seconds, so as to give the fiber good crystallinity and dimensional stability.
10. The RPET fiber prepared by the method for preparing the RPET fiber according to any one of claims 1 to 9, comprising an RPET fiber body, characterized in that: The RPET fiber body is divided into antibacterial RPET fiber, anti-ultraviolet RPET fiber and conductive RPET fiber. The antibacterial RPET fiber is composed of 93% RPET basic raw material, 5% nano silver antibacterial agent, 1% quaternary ammonium salt organic antibacterial agent and 1% antistatic agent. The anti-ultraviolet RPET fiber is composed of 90% RPET basic raw material, 4% nano titanium dioxide, 4% benzotriazole ultraviolet absorber and 2% softener. The conductive RPET fiber is composed of 89% RPET basic raw material, 7% conductive carbon black, 3% polythiophene conductive polymer and 1% antistatic agent.