789 results about "Depolymerization" patented technology

The invention discloses an efficient purification method of rBHET, and belongs to the technical field of waste polyester recycling. A reaction raw material obtained after premixing of waste PET polyester raw material particles and a catalyst and ethylene glycol are jointly and continuously introduced into a depolymerization reactor, the reaction raw material and ethylene glycol in the depolymerization reactor are mixed and pass through a plurality of rotating discs, and the materials form a flowing film on the rotating discs rotating at a high speed to promote depolymerization; depolymerization reaction liquid generated in the depolymerization reactor enters a temporary storage tank to be stored after being subjected to impurity removal, the depolymerization reaction liquid in the storage tank is introduced into a rectifying tower to be primarily concentrated and purified, obtained concentrated liquid enters an evaporator to be secondarily concentrated and purified, obtained secondary concentrated liquid enters a cooler to be cooled and then enters a product tank to be crystallized; and drying the crystallized solid to obtain a high-purity rBHET product. According to the method, the production efficiency is improved, and the purity of rBHET is effectively improved.

The invention belongs to the field of carbon nanomaterials, and provides a method for preparing a carbon quantum dot material doped with elements such as silicon and aluminum by oxidative depolymerization and stripping of coal gangue. Comprising the steps of screening and matching of coal gangue, oxidative depolymerization stripping, centrifugal dialysis membrane filtration and modification, drying and the like, raw materials and all the steps are specifically set, and the particle size or fluorescence performance of fluorescent carbon dots can be specifically selected and set according to selective oxidative depolymerization stripping conditions. The main particle size of the prepared multi-inorganic-element doped carbon quantum dot material is kept within the range of 1.5-2.0 nm, the structure is stable, the optical performance also meets the requirements, and the material can be further modified and is expected to be applied to the fields of photovoltaic equipment, biological imaging, photocatalytic degradation of organic pollutants or sensing and the like.

The invention belongs to the technical field of emulsion materials, and particularly relates to metal-polyphenol network modified coconut protein composite particles as well as a preparation method and application thereof. The preparation method comprises the following steps: preparing a coconut protein-pectin compound by taking coconut protein and pectin as raw materials, adding a tannic acid solution into the coconut protein-pectin compound, mixing, adding a Fe < 3 + > solution, and mixing to obtain metal-polyphenol network modified coconut protein composite particles; according to the preparation method, tannic acid and the coconut protein-pectin compound are subjected to non-covalent interaction, Fe < 3 + > and phenolic hydroxyl groups on the tannic acid are subjected to coordination reaction, a metal-polyphenol network is formed through cross-linking of Fe-O coordination bonds, and a compact modification layer is constructed on the surface of the coconut protein-pectin compound, so that on one hand, waste coconut protein resources are utilized; on the other hand, the problem that composite particles prepared from pectin and coconut protein are prone to depolymerization is solved, the structural stability is improved, and meanwhile iron and polyphenol are supplemented.

The invention relates to the technical field of graphene processing, and particularly discloses a nano graphene powder preparation method which comprises the following steps: weighing a graphite raw material; opening a discharge valve of the feeding cabin, and feeding the graphite raw material into the pressure stabilizing cabin; a graphite raw material is sucked into a first-stage jet mill high-pressure cabin from a pressure stabilizing cabin, first-stage jet milling is conducted, and a first-stage abrasive material is obtained; the first-stage grinding material with the thickness not larger than 10 micrometers is conveyed to a second-stage jet mill high-pressure cabin; processing the first-stage abrasive material by a second-stage jet mill high-pressure cabin to obtain a second-stage abrasive material; the second-stage grinding material with the thickness not larger than 100 nanometers is conveyed to a flow energy depolymerization cabin; the flow energy depolymerization cabin is used for processing the secondary grinding material, and nano graphene powder is obtained through screening; the high-purity graphite raw material is processed through a three-stage gradient processing framework, a negative feedback regulation scheme is introduced in each processing link, the quality of products in different stages is controlled, a progressive processing technology is constructed, and the product rate is greatly increased.

This invention belongs to the field of high-value utilization technology of biomass resources, and discloses a method for catalyzing the depolymerization of lignin into phenolic compounds using a RuNiZn / Nb2O5 catalyst. The method includes: uniformly mixing the RuNiZn / Nb2O5 catalyst, lignin-containing biomass feedstock, and water; stirring under hydrogen atmosphere to carry out the depolymerization reaction; after the reaction, cooling to room temperature and performing solid-liquid separation; evaporating the solvent to obtain the hydrogenated depolymerization product containing monophenols. In this invention, the RuNiZn / Nb2O5 catalyst employs a technique of replacing precious metals with various non-precious metals, which improves the catalyst's reactivity and reduces the amount of precious metals used. This increases the yield of lignin depolymerization products, provides milder depolymerization reaction conditions, and ultimately significantly reduces the catalyst preparation cost and the energy cost of the lignin depolymerization process.

A polymerization raw material obtained by the depolymerization of waste polyester is disclosed. The polymerization raw material contains recycled bis(2-hydroxyethyl) terephthalate in which the contents of acetate-based ester compounds and diethylene glycol ester compounds are adjusted to specific levels. The polymerization raw material is excellent in purity and quality, and free from the problem that thermal resistance characteristics deteriorate in the polymerization of a polymer from the recycled monomer.

The application belongs to the technical field of regenerated polyester, and particularly relates to a recycling method of waste polyester textiles, which comprises the following steps: decolorizing colored waste polyester textiles by using a decolorizing agent, wherein the decolorizing agent is one or more of dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate; depolymerizing the decolorized polyester textiles by using a depolymerizing agent to obtain terephthalate, wherein the depolymerization rate of the decolorized polyester textiles is 98.0-100%; converting the terephthalate into DMT first, and then performing a re-polymerization reaction on the DMT, ethylene glycol, a catalyst and a functional additive to obtain regenerated PET. The application adopts a process of decolorizing first and then depolymerizing, and the decolorizing and depolymerizing are coordinated, so that the process is simplified, the energy consumption and pollution are reduced, and the economy and sustainability of the recycling of waste polyester textiles are improved.

Disclosed is a process for hydrolytic depolymerization of a polyamide contained in a chemical feedstock F, wherein the process comprises: providing the chemical feedstock F; providing a liquid aqueous stream SW; preparing a mixture comprising the raw material F and the liquid aqueous stream SW and subjecting said mixture to polyamide 6 depolymerization conditions in a chemical reaction unit UR, thereby obtaining an aqueous stream SE exiting the UR, the stream SE comprising epsilon-caprolactam, wherein the mixture to be subjected to polyamide 6 depolymerization conditions comprises polyamide 6 and further comprises polyethylene terephthalate and polyamide 6.6 in a mass ratio rS = (mPA6.6 + mPET) / mPA6, wherein 0.01 < = rS < = 2.5.

The invention discloses a method for preparing high-value chemicals through photocatalytic driving of beta-O-4 lignin depolymerization and coupling cascade reaction, and belongs to the technical field of photocatalytic biomass resource conversion. The method comprises the following steps: (1) dispersing a beta-O-4 lignin raw material into a solvent containing a photocatalyst; (2) introducing a normal-temperature chemically stable gas to replace air in a reaction system; and (3) carrying out a depolymerization reaction of beta-O-4 bonds and an in-situ C-C bond coupling reaction under an illumination condition to generate a target product. And (4) separating and purifying the product and recovering the catalyst. Through photocatalytic cascade reaction design, the defects of harsh reaction conditions and multi-step separation in a traditional method are avoided, the method has the advantages of mild reaction conditions, high atom utilization rate, high product selectivity and environmental friendliness, and a new way is provided for high-value utilization of lignin.

A recycling system comprises a partial depolymerization unit 730, which partially decomposes a solid material, such as PET flakes containing a polymer to be recycled, into a depolymerized product through a depolymerization reaction; a solid-liquid separation unit 740, which separates a solid component and a liquid component obtained in the partial depolymerization unit 730; and a recycling device that performs a recycling process on the solid component. The recycling device is a mechanical recycling device 900, which performs a mechanical recycling process on the solid component. The recycling system also includes a chemical recycling device 100, which performs a chemical recycling process on the liquid component.

The invention discloses a method for recovering monohydroxyethyl terephthalate from a polyester textile, which comprises the following steps: carrying out multi-stage decolorizing treatment on the polyester textile to be recovered by using ethylene glycol as a decolorizing agent to obtain the decolorized polyester textile; mixing a depolymerization catalyst, a sodium phosphate buffer solution and the decolored polyester textile, and carrying out a depolymerization reaction to obtain a depolymerization solution; adding ethyl acetate into the depolymerization liquid for extraction, rotary evaporation concentration and sublimation treatment to obtain monohydroxyethyl terephthalate. According to the method for recycling the monohydroxyethyl terephthalate from the polyester textile, the decolorization rate of the polyester textile can reach 90% or above, the purity of the recycled monohydroxyethyl terephthalate is larger than 98%, and the whiteness of the recycled monohydroxyethyl terephthalate is larger than 97%. The method for recycling the monohydroxyethyl terephthalate from the polyester textile, provided by the invention, is an efficient, economical and green new method for recycling the polyester, and the recycling of the polyester textile is realized.

A recycling system comprises a quality determination unit 710, which determines the quality of a solid material, such as PET flakes containing a polymer to be recycled, based on a predetermined quality determination criterion; a material sorting unit 720, which sorts the solid material into a high-quality material, which is determined to have a quality higher than the quality determination criterion, and a low-quality material, which is determined to have a quality lower than the quality determination criterion; a mechanical recycling device 900, which carries out a mechanical recycling process on the high-quality material; and a chemical recycling device 100, which carries out a chemical recycling process on the low-quality material.The chemical recycling device 100 includes a reaction vessel 300 for depolymerization, which decomposes the low-quality material into a depolymerized product through a depolymerization reaction; foreign material removal devices 340 to 360, which remove foreign material from the depolymerized product; a reaction vessel 400 for polymerization, which synthesizes the depolymerized product into a polymer through a polymerization reaction; and a polymerization promotion device 500, which increases the degree of polymerization of the polymer.

The present invention provides a method for recovering ε-caprolactam and polyether polyurethane from a material comprising nylon 6 and polyether polyurethane in a plant, wherein the plant comprises a separation section [B], a depolymerization section [C], a recovery section [D], and a purification section [E].

The invention relates to a reaction process for recovering BHET by depolymerizing PET, belonging to the technical field of high polymer material recovery. The process comprises the following steps: mixing a raw material containing waste PET particles and ethylene glycol with a sylvite catalyst, placing the mixture in a closed container, carrying out a depolymerization reaction in an inactive atmosphere to obtain a depolymerization solution, mixing the depolymerization solution with methanol and BHET seed crystals, carrying out an ester exchange reaction to obtain a reaction solution, cooling the reaction solution to 25 DEG C at a speed of 10 DEG C / min, crystallizing for 3-6 hours, carrying out acid pickling, and drying to obtain the PET / BHET composite material. A BHET crystal is obtained; pressure oscillation is intermittently carried out in the depolymerization reaction process. The low-temperature depolymerization rate is increased by adopting the potassium salt catalyst, and meanwhile, directional migration of impurities is induced through periodic pressure change, so that full-continuous operation is realized.

The invention discloses a surface zinc-loaded molecular sieve catalyst for PET (polyethylene terephthalate) depolymerization and a preparation method of the surface zinc-loaded molecular sieve catalyst. According to the catalyst, a molecular sieve with a framework silica-alumina ratio of 25-400 is adopted as a carrier, and zinc species are strongly loaded on the outer surface of the molecular sieve through chemical bonding. The preparation method comprises the following steps: dissolving a zinc source in water, and adjusting to a specific pH value by using inorganic acid to obtain a zinc-containing solution; dipping a molecular sieve carrier in the solution under a heating condition; and finally, filtering, washing, drying and roasting to obtain a finished product. The catalyst successfully solves the problem that reaction activity and separability of a traditional solid catalyst in PET glycol alcoholysis are difficult to consider at the same time by accurately regulating and controlling active site distribution, shows high activity and excellent cycling stability close to those of a homogeneous catalyst, and has remarkable industrial application potential.

The method involves chemically and selectively recycling polyamide (PA) polymers from compositions comprising other polymers, by mixing such a composition with a molar excess of an aliphatic dicarboxylic acid and heating the mixture to a non-melting temperature of the polymers for a minimum of 2 hours. This results in a solution comprising depolymerization products of the polymers. The solution can optionally be treated to recover these products. The aliphatic dicarboxylic acids can be of a specific formula, and the method can be carried out under atmospheric pressure. The mixture can be heated to a temperature between 100°C and 200°C for about 2 to 4 hours. The PA polymer can be an amorphous or semi-crystalline polyamide, and the aliphatic dicarboxylic acid can be selected from a specific group. The depolymerization products can be Aminocaproic acid derivatives, which can be used in the synthesis of resins for coatings or as plasticizers in PVC and nylon resins.

The application belongs to the technical field of polymer material recycling, and particularly relates to a high-efficiency enzymatic hydrolysis process of polycaprolactam. The high-efficiency enzymatic hydrolysis process of polycaprolactam provided by the application comprises the steps of acid pretreatment, enzymatic catalytic depolymerization and product post-treatment. The process combines sulfuric acid and a multi-enzyme system to treat PA6 with high substrate concentration. The physical form and chemical accessibility of PA6 are significantly changed through sulfuric acid pretreatment, which creates conditions for subsequent enzymatic hydrolysis reaction, and realizes efficient, deep and green degradation of PA6.

The utility model discloses a depolymerization kettle feeding device capable of improving efficiency, and relates to the technical field of depolymerization kettles.The depolymerization kettle feeding device comprises a machine base, a kettle body arranged on the machine base and a kettle cover arranged at the top of the kettle body, a feeding pipe is arranged at the top of the kettle cover, a sealing cover is movably arranged on the feeding pipe, and a rotating device is arranged at the top of the kettle cover; according to the present invention, the material is added into the kettle body through the feeding pipe, the material falls on the centrifugal dispersion structure during the falling process, and the material is dispersed through the rotation of the centrifugal dispersion structure so as to disperse the material to the periphery, such that the material can be uniformly dispersed; the centrifugal stopping structure stops the materials dispersed at different positions, so that the materials are dispersed in the adding process, accumulation of the materials is avoided, the step of dispersing the materials after the materials are added into the kettle body is omitted, and the depolymerization efficiency is improved.

The application discloses a kind of bifunctional thick oil catalytic viscosity reduction system and viscosity reduction method, bifunctional thick oil catalytic viscosity reduction system is adjusted to be the catalytic-emulsion composite viscosity reduction system of mixed catalyst, oxidizing agent after using surfactant, wherein, catalyst is amphiphilic TM / C-NH2 Nanoparticle, the oxidizing agent is organic peroxide.Catalytic-emulsion composite viscosity reduction system is mixed with thick oil and heated to reservoir environmental temperature reaction after, reaction is completed after finishing to thick oil viscosity reduction.The application is configured into the catalytic-emulsion composite viscosity reduction system of water-in-oil by organic peroxide oxidizing agent compound emulsifier, in reservoir environment (50~180 DEG C), using the catalytic oxidation performance of catalyst viscosity reduction system and catalyst and oxidized oil oxygen-containing group adsorption self-assembly function, realize thick oil macromolecule depolymerization and wettability reverse, further improve the viscosity reduction efficiency.

A comprehensive utilization method of beneficiation-metallurgy-chemical combination for germanium-rich lignite includes the following steps: 1) germanium-rich lignite sizing and grinding, 2) catalytic pre-oxidation, 3) nitric acid leaching, and 4) recycling and enrichment of germanium solution. The high effective extraction of germanium from the germanium-rich lignite was achieved via a combination of mineral beneficiation, hydrometallurgy, and chemical processing. Meanwhile, a high yield and high degree of depolymerization humic acid product was produced as byproducts. This method could not only effectively avoid high carbon emission and organic resource waste during conventional germanium-rich lignite pyrometallurgical processing, but also could produce humic acid as quality raw materials for metallurgical and agricultural industries, which has advantages of less environmental pollution, high extraction efficiency, and low comprehensive costs.

The invention discloses bagasse-based hard carbon based on fiber reconstruction as well as a preparation method and application thereof. The preparation method comprises the following steps: (1) washing, drying and crushing bagasse to prepare bagasse powder; (2) putting the obtained bagasse powder and an alkaline substance into a water medium, reacting under heating and stirring conditions, and filtering to obtain depolymerized slurry; (3) forming the obtained depolymerized slurry into a flaky precursor and drying the flaky precursor; (4) performing high-temperature carbonization treatment on the dried flaky precursor in an inert atmosphere, and cooling to room temperature after the reaction is finished to obtain bagasse-based hard carbon; through a three-step strategy of crushing, softening and recombination, reconstruction of an original bagasse fiber structure is realized, the microstructure of bagasse derived hard carbon can be effectively regulated and controlled, sodium storage sites are further increased, sodium ion migration obstruction is reduced, and the performance of the bagasse derived hard carbon negative electrode material is greatly improved.

According to the device and the method for determining the content of the foreign substances in the polyester material, provided by the invention, alcoholysis reaction and filtering separation functions are integrated in the same device, so that the integration of a test process is realized. The device adopts a structure capable of being inversely arranged, and can be used as a reaction container when being inversely arranged, so that full alcoholysis of a polyester matrix is realized under high-temperature and high-pressure conditions; and the filtering efficiency can be improved through the internal and external pressure difference. The loss and pollution of foreign substances caused by sample transfer in a traditional method are avoided, and the test accuracy is improved from the source. In the aspect of the method, a hot ethanol circulating washing mechanism is introduced, so that residual depolymerization products are effectively dissolved and removed at a proper temperature, and pure retention of foreign substances is ensured. The whole determination process is completed in the same device, the operation steps are simplified, the analysis time is shortened, and the device has the comprehensive advantages of high test precision, wide applicability and the like.

The application belongs to the field of solid waste plastic resource utilization, and discloses a method for depolymerization and recovery of polycaprolactone by low-temperature plasma coupling catalysis. Polycaprolactone particles are subjected to plasma discharge treatment together with a catalyst to make the polycaprolactone particles depolymerize, thereby realizing the depolymerization and recovery of polycaprolactone. The application utilizes the Joule heat generated by plasma discharge to liquefy polycaprolactone, and after liquefaction, the polycaprolactone fully contacts the active sites of the catalyst, and meanwhile, under the action of active free radicals generated by plasma treatment and the catalyst, realizes fast polycaprolactone depolymerization and recovery without external heat source, solvent and pressure. The complete conversion of polycaprolactone is realized within 1 hour, and the yield of gamma-caprolactone monomer can be as high as 88.9%, which is significantly better than the current solvent thermal method.

A method of recycling plastic waste by feeding a quantity of PET and metal-containing reclaimer co-product separated from the plastic waste to a chemical recycling facility, the quantity of metal-containing co-product comprises plastic flakes and at least 0.1 weight percent metals; and depolymerizing in the chemical recycling facility at least a portion of the plastic flakes; or depolymerizing in the chemical recycling facility at least a portion of the plastic articles, wherein the chemical recycling facility comprises a solvolysis facility for the depolymerization and the solvolysis facility is a methanolysis facility, and wherein the plastic articles are in the form of compressed bales; which further comprises processing at least a portion of the compressed bales to thereby produce a debaled quantity of plastic articles and the metals; and wherein the processing comprises reducing the size of the bales to form a quantity of plastic particulate solids having a D90 particle size of less than 2.54 cm (1 inch).

The invention relates to the technical field of polyester degradation, in particular to a selective depolymerization method of polyester in a polyester composite material. The selective depolymerization method comprises the following steps: carrying out a depolymerization reaction on a polyester composite material, a cosolvent, a depolymerization agent and a basic catalyst at normal pressure and a temperature not higher than 65 DEG C, the cosolvent is at least one of an ethylene glycol diether compound, a propylene glycol diether compound and an isobutyl ketone compound. According to the selective depolymerization method, an ethylene glycol diether compound, a propylene glycol diether compound and an isobutyl ketone compound are used as cosolvents, a depolymerization agent is used as a methylation reagent, and directional polyester depolymerization of a polyester composite material can be realized at normal pressure and the temperature not higher than 65 DEG C; when the polyester material is degraded, the non-polyester material is basically not degraded or depolymerized, and the selective depolymerization and separation of the polyester composite material such as a polyester blended fabric can be realized.

This application relates to a semi-continuous process for producing polyamide and a polyamide product, comprising the following steps: adding a batch of polyamide salt solution to a reactor for polymerization; after discharge, introducing steam containing a depolymerization aid into the reactor to depolymerize the residual material online, forming a prepolymer with a molecular weight of 2000-4000; wherein the mass concentration of the depolymerization aid in the steam containing the depolymerization aid is 0.1%-10%, the depolymerization aid is selected from organic monobasic acids, and the boiling point of the depolymerization aid is 100℃-180℃; then, the next batch of polyamide salt solution is directly added to the reactor, and polymerization and online depolymerization are carried out in a cyclical manner. The process provided by this application can significantly improve product quality, increase production efficiency and material utilization, effectively reduce the risk of reactor damage, and improve production safety.

The invention relates to a method for continuously producing poly (p-dioxanone), which comprises the following steps: premixing glycollic acid or a glycollic acid derivative with a ring formation catalyst, and introducing the obtained mixed material and ethylene oxide into a synthesis reaction kettle for reaction; separating and purifying the obtained reaction product, introducing the obtained purified monomer into a polymerization reaction kettle, and adding a polymerization catalyst for polymerization; after polymerization is finished, discharging is conducted, residual materials in the polymerization reaction kettle are subjected to depolymerization treatment to clean the kettle body, after depolymerization is finished, depolymerization products generated in the depolymerization treatment process are discharged, the kettle does not need to be opened for cleaning, and the next round of polymerization production is directly conducted. According to the method disclosed by the invention, the steps of synthesizing the p-dioxanone monomer, separating and purifying the monomer, catalyzing and polymerizing, depolymerizing and cleaning the kettle body and the like are continuously carried out, so that the continuous production of the poly (p-dioxanone) is realized, the side reaction of oligomerization and degradation of the p-dioxanone in storage and transportation can be avoided, and the production cost of the poly (p-dioxanone) is obviously reduced.

The invention relates to a reactor, in particular for carrying out polycondensation or depolymerization reactions, comprising at least one inlet, at least one product outlet line, a liquid zone, an inner zone arranged above the liquid zone, and a gas zone comprising at least one gas outlet line, wherein the gas zone is arranged above the inner zone, and wherein the gas zone has a larger cross-sectional area than the inner zone, and wherein the gas zone comprises a demisting element connected to a scrubbing liquid inlet disposed in the gas zone and a scrubbing liquid outlet disposed in the gas zone, and wherein the inner region comprises one or more inner components selected from the group consisting of a structured packed bed, a random packed bed and a hybrid heat exchange element for increasing the surface to volume ratio within the inner region wherein the one or more inner components have a specific surface area of 10 to 1,000 m2 / m3.

The application discloses a preparation and by-product recycling process of acesulfame potassium, and belongs to the technical field of food additive production and processing. Amino sulfonic acid is added into N-butyl pyridine hydrogen sulfate ionic liquid and triethylamine in batches to obtain a homogeneous mixed solution; secondly, the mixed solution and diketene are introduced into a micro-channel reactor to perform a condensation reaction; and the discharge liquid is introduced into a polystyrene sulfonic acid resin loaded SO3 fixed bed reactor to perform a cyclization reaction; subsequently, the cyclization product is subjected to hydrolysis, decolorization, potassium salt crystallization and drying to obtain the acesulfame potassium product; and the crystallization mother liquor is separated through a nanofiltration membrane, and the intercepted liquid is an ionic liquid and triethylamine mixture, which is directly reused. The application inhibits the self-polymerization of diketene through the micro-channel reactor, replaces concentrated sulfuric acid with solid acid to avoid waste acid pollution, and realizes efficient recycling of by-products by combining nanofiltration membrane separation and catalytic depolymerization technology, and has the characteristics of green environmental protection and economic efficiency.

The invention discloses a dyeing-free black soft polyester fiber and a preparation method thereof, and belongs to the technical field of waste polyester recycling. The preparation method comprises the following steps: melting and extruding waste PET (Polyethylene Terephthalate) with the intrinsic viscosity of 0.50-0.80 dL / g through a twin-screw extruder, and depolymerizing in an EG / BHET homogeneous system to obtain an oligomer with the polymerization degree of 5-7; mixing with carbon black slurry and a polycondensation catalyst, and carrying out pre-polycondensation and final polycondensation to obtain regenerated functional polyester; and finally, carrying out melt spinning under the conditions that the temperature is 275-285 DEG C and the speed is 2500-3500 m / min, so as to obtain the fiber with the monofilament of 0.5-2.0 dtex, the tensile modulus of 30-60 cN / dtex and the color fastness of more than or equal to grade 4. By accurately controlling the depolymerization degree and the dispersion system, the problems of pigment agglomeration, complex process and high fiber modulus in the prior art are solved, high-added-value recycling of the waste PET is realized, and the product can be used for close-fitting textiles.