CN114656684A - Method for preparing high-purity recycled PET (polyethylene terephthalate) polyester by using waste PET polyester - Google Patents
Method for preparing high-purity recycled PET (polyethylene terephthalate) polyester by using waste PET polyester Download PDFInfo
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- C08J11/00—Recovery or working-up of waste materials
- C08J11/04—Recovery or working-up of waste materials of polymers
- C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
- C08J11/18—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material
- C08J11/22—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material by treatment with organic oxygen-containing compounds
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- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
- C08G63/12—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds
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Abstract
The invention discloses a method for preparing high-purity recycled PET polyester by using waste PET polyester, which comprises the following steps: carrying out crushing, washing and drying pretreatment on the waste PET polyester; carrying out alcoholysis on the pretreated waste PET polyester in ethylene glycol to obtain BHET alcoholysis liquid; purifying the BHET alcoholysis solution to obtain a high-purity BHET monomer with the HPLC purity of more than 99.0%; and carrying out pre-polycondensation reaction and final polycondensation reaction on the high-purity BHET monomer to obtain the high-purity regenerated PET polyester. The method obtains the high-purity BHET monomer by adopting a purification treatment method combining reduced pressure concentration with reduced pressure evaporation in a film evaporator and rectification in a short-path distiller for the BHET alcoholysis liquid, simplifies the recovery and regeneration process of waste PET polyester, obviously reduces the use of organic solvent, obviously reduces energy consumption and cost, breaks through the bottleneck that the BHET is difficult to decolor and purify, and can obtain a regenerated PET polyester product which is comparable with the indexes of the primary PET polyester.
Description
Technical Field
The invention relates to a method for preparing high-purity recycled PET (polyethylene terephthalate) polyester by using waste PET polyester, belonging to the technical field of recycling of waste polyester.
Background
PET polyester (i.e., polyethylene terephthalate) is a saturated polyester obtained by Polymerizing Terephthalic Acid (PTA) or dimethyl terephthalate (DMT) with Ethylene Glycol (EG), and has been widely used in the fields of food packaging, film sheets, electronic devices, mechanical devices, etc. because of its excellent physicochemical properties. According to statistics, the yield of the PET polyester in 2008 is the first major country for producing and consuming PET polyester in the world, the yield accounts for more than half of the world, the yield of the PET polyester in 2015 reaches 3530 ten thousand tons, the yield of the PET polyester in 2019 reaches 5006 ten thousand tons, the amplification reaches 41.8%, and the yield of the PET polyester in 2020 is estimated to reach 5327 ten thousand tons. Most of PET polyester products become waste products after being used for one time, so the output of waste PET polyester is increased along with the rapid development of the PET polyester industry. However, the PET polyester has strong chemical inertness, and is difficult to degrade after being naturally stored or decomposed by microorganisms, which not only causes huge resource waste, but also causes serious environmental pollution, so how to realize the virtuous cycle of recycling and reusing the PET polyester becomes an important subject which cannot be avoided and needs to be solved urgently in the development of the current PET polyester industry.
The recovery method of waste PET polyester in the prior art mainly comprises a physical method and a chemical method, wherein the physical method comprises the following steps: the physical method is to directly blend, blend and granulate the waste PET polyester and the products thereof to prepare regenerated slices, although the process is simple, the performance of the regenerated products is poor, only degraded use can be realized, and the true cyclic regeneration of the waste PET polyester cannot be realized; the chemical method is to decompose PET polyester into smaller molecules and intermediate raw materials through alcoholysis or directly convert the smaller molecules and the intermediate raw materials into monomers and then perform polycondensation to obtain the PET polyester, so that the cyclic regeneration of the waste PET polyester can be realized in a real sense, and the method has important practical significance.
At present, the approaches for chemically recycling PET polyester mainly include: pyrolysis, hydrolysis, glycolysis, methanolysis, other alcoholysis processes and amine/ammonolysis processes, of which glycolysis is the preferred method for industrialization because of its high boiling point of the solvent and the fact that the reaction is carried out at atmospheric pressure. However, the current glycolysis technology at home and abroad is still imperfect, and the overall economy is not high. The main reasons are: the waste PET polyester has a complex source, and the depolymerized product BHET has a dark color due to the colored PET polyester raw material. And because BHET has high boiling point (432.1 ℃) and active group (hydroxyl), BHET can generate polycondensation reaction for removing glycol in the conventional reduced pressure distillation process to become PET polyester, so that no good method for decoloring BHET at present exists, and the BHET becomes another bottleneck for recovering PET polyester by glycolysis. In order to effectively avoid the generation of colored byproducts in the alcoholysis process, and because the boiling point of dimethyl terephthalate (DMT) is lower than that of ethylene terephthalate (BHET), and the dimethyl terephthalate (DMT) has good high-temperature stability, is convenient for subsequent decoloration and purification, and is easy to prepare a high-purity product, the prior art mainly adopts the steps of firstly alcoholysis of waste PET polyester with Ethylene Glycol (EG) to bis-hydroxy terephthalate (BHET) or an oligomer, then carrying out transesterification reaction in methanol to generate dimethyl terephthalate (DMT) and ethylene glycol, and purifying the DMT to be used for preparing regenerated polyester.
The Chinese patent application with the application number of 201810921762.3 discloses a method for recycling waste polyester textiles, which comprises the steps of carrying out alcoholysis on the waste polyester textiles in ethylene glycol to obtain crude BHET by taking zinc acetate as a catalyst, then carrying out purification treatment on the crude BHET to obtain a refined BHET monomer, and then carrying out pre-polycondensation reaction and final polycondensation reaction on the refined BHET monomer to obtain regenerated polyester. Although the method avoids the problem of methanol safety risk existing in the ester exchange method by directly alcoholyzing a BHET monomer to perform a polyester polycondensation reaction, the method still cannot well solve the problem of decolorization of BHET, and even if the method can improve the color to a certain extent through recrystallization purification and activated carbon decolorization procedures, experimental results in the embodiment of the application show that the color b value of the regenerated polyester particles obtained by the method is between 6 and 8, so that the reapplication level of the regenerated polyester is limited; in addition, the purification treatment method of the patent application for BHET comprises the following steps: adding 90 ℃ hot water into crude BHET subjected to reduced pressure distillation, wherein the using amount of the hot water is 200% of the mass of the alcoholysis liquid subjected to reduced pressure distillation, then stirring, filtering, repeatedly washing with water for 3-5 times, decoloring with activated carbon, filtering, cooling the decolored filtrate to 40 ℃ to crystallize and separate out BHET, and drying the filtered refined BHET at 60 ℃; the purification treatment method can generate more wastewater and waste glycol, so that the pressure for treating the wastewater is high, the problems of difficult hot filtration (easy filter blockage), long time for decoloring and cooling precipitation of activated carbon, difficult drying and the like exist, and the chromaticity and purity of the obtained BHET can not meet the requirements for preparing high-requirement PET products.
Disclosure of Invention
Aiming at the problems in the prior art, the invention aims to provide a method for preparing high-purity regenerated PET (polyethylene terephthalate) by using waste PET, which has the advantages of simple process, low energy consumption, high safety and easiness in large-scale production.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for preparing high-purity recycled PET polyester by using waste PET polyester comprises the following specific steps:
A) carrying out crushing, washing and drying pretreatment on the waste PET polyester;
B) carrying out alcoholysis on the pretreated waste PET polyester in ethylene glycol to obtain BHET alcoholysis liquid;
C) purifying the BHET alcoholysis solution to obtain a high-purity BHET monomer with the HPLC purity of more than 99.0%;
D) carrying out pre-polycondensation reaction and final polycondensation reaction on the high-purity BHET monomer to obtain high-purity regenerated PET polyester;
wherein the purification treatment in step C) comprises the following operations:
C1) filtering the BHET alcoholized solution obtained in the step B) to remove insoluble substances in the BHET alcoholized solution;
C2) concentrating the filtrate obtained in the step C1) under reduced pressure at 100-140 ℃ and 1-10 KPa;
C3) adding the concentrated solution subjected to the reduced pressure concentration in the step C2) into a thin film evaporator, and performing reduced pressure evaporation at the temperature of 130-160 ℃ and the pressure of 0.1-1 KPa;
C4) and D, adding the residue subjected to reduced pressure evaporation in the step C3) into a short-path distiller, rectifying at the temperature of 150-200 ℃ and the pressure of 1-10 Pa, and crystallizing the collected fraction at normal temperature to obtain a white solid, namely the high-purity BHET monomer with the HPLC purity of more than 99.0%.
In a preferred scheme, the drying in the step A) means that the water content of the waste PET polyester is less than or equal to 3 percent.
In one embodiment, the alcoholysis process of step B) is as follows:
putting Ethylene Glycol (EG) and the pretreated waste PET polyester particles into an alcoholysis reaction kettle according to the mass ratio of (1-3) to 1, then putting a zinc acetate catalyst with the mass of 0.1-0.5% of the mass of the waste PET polyester particles, heating to 190-230 ℃, controlling the pressure in the alcoholysis reaction kettle to be 0.1-0.5 MPa, and carrying out alcoholysis reaction for 2-6 hours.
In a preferred embodiment, the concentration under reduced pressure in step C2) is carried out in a thin-film evaporator.
In one embodiment, the conditions of the prepolycondensation reaction in step D) are: under the action of ethylene glycol antimony catalyst, firstly stirring and reacting for 1-1.5 hours at 265-270 ℃ and under the pressure of 8-12 KPa in the kettle, and then stirring and reacting for 2-2.5 hours at 272-275 ℃ and under the pressure of 1-1.5 KPa in the kettle.
In one embodiment, the conditions of the final polycondensation reaction in step D) are: stirring and reacting for 2-2.5 hours at 278-282 ℃ and the pressure in the kettle of 100-400 Pa.
In one embodiment, the waste PET polyester comprises at least one of waste PET bottles, PET packaging sheets, PET fibers, PET textiles and PET bubble materials.
Compared with the prior art, the invention has the following beneficial effects:
the invention directly obtains the high-purity BHET monomer with the HPLC purity of 99.8 percent by creatively adopting a purification treatment method combining reduced pressure concentration with reduced pressure evaporation in a film evaporator and rectification in a short-path distiller for BHET alcoholysis liquid, thereby directly carrying out polycondensation to prepare the high-purity regenerated PET polyester without ester exchange, simplifying the recovery and regeneration process of waste PET polyester, obviously reducing the use of organic solvent, obviously reducing the energy consumption and cost, breaking through the bottleneck that BHET is difficult to decolor and purify, and enabling the color value b value of the regenerated PET polyester to be within the range of 1.0 +/-2.0; and, the experiment proves that: the method of the invention can obtain the regenerated PET polyester product which is comparable to the original PET polyester excellent product index.
In a word, the method has low requirement on the source of the waste PET polyester raw material, is easy to realize large-scale production, and the obtained regenerated PET polyester product can be used in high-requirement and high-added-value applications, has important significance and value on realizing the regeneration cycle of the waste PET polyester in the true sense, and has significant progress compared with the prior art.
Drawings
FIG. 1 is a HPLC analysis spectrum of the residue after evaporation under reduced pressure of step C3); in the figure: the peak with the retention time of 3.504min is BHET, the peak with the retention time of 4.618min is BHET dimer, and the peak with the retention time of 7.091min is BHET trimer;
FIG. 2 is a HPLC analysis spectrum of the high purity BHET monomer obtained in the example; in the figure: the peak with retention time of 3.465min is BHET monomer;
FIG. 3 is a nuclear magnetic resonance analysis spectrum of the high purity BHET monomer obtained in the example; in the figure: δ 0ppm is a solvent peak of tetramethylsilane as an internal standard, δ 7.26ppm is a solvent peak of deuterated chloroform, δ 8.13ppm is a proton peak corresponding to hydrogen on a benzene ring in BHET, δ 4.51ppm and 4.00ppm are proton peaks of four hydrogen atoms on two methylene groups in BHET, respectively, and δ 2.14ppm is a proton peak of a hydrogen atom on a hydroxyl group in BHET;
FIG. 4 is an HPLC analysis spectrum of the final fraction obtained in the comparative example;
FIG. 5 is a nuclear magnetic resonance analysis spectrum of a final fraction obtained in the comparative example; in the figure: δ is 5.22ppm of the proton peak of four hydrogen atoms on two methylene groups in ethylene glycol, and δ is 3.68ppm of the proton peak of hydrogen atom on hydroxyl group in ethylene glycol.
Detailed Description
The technical scheme of the invention is further detailed and completely explained by combining the embodiment and the comparative example.
The HPLC analysis conditions were as follows:
an Agilent-1100 type high performance liquid chromatograph, the specification of chromatographic column is Benetnach C18, 5 μm, 4.6 x 150mm, the solvent is acetonitrile, the detection wavelength is 254nm, the mobile phase is acetonitrile-water (70:30, V/V), the flow rate is 0.5mL/min, and the sample introduction amount is 20 μ L;
the nmr analysis conditions were as follows: an AVANCE III 400 model nuclear magnetic resonance spectrometer, and 1H NMR test is carried out on the product under the condition of 400 MHz.
Examples
A method for preparing high-purity recycled PET polyester by using waste PET polyester comprises the following specific steps:
A) crushing waste PET polyester (including PET bottles, PET packaging sheets, PET fibers, PET textiles, PET bubble materials and the like), cleaning and dehydrating to obtain waste PET polyester particles with the water content of 1-3%;
B) measuring 1 ton of pretreated waste PET polyester particles, conveying the waste PET polyester particles to an alcoholysis reaction kettle, adding 2 tons of EG and 3kg of zinc acetate catalyst, heating to 200 ℃ and controlling the pressure in the alcoholysis reaction kettle to be 0.1MPa, and carrying out alcoholysis reaction for 3 hours to obtain BHET alcoholysis solution;
C) purifying BHET alcoholysis liquid, namely:
C1) filtering the BHET alcoholized solution obtained in the step B) by using a filter of 50-150 meshes to remove insoluble substances in the BHET alcoholized solution;
C2) concentrating the filtrate obtained in the step C1) under reduced pressure at 100-140 ℃ and 1-10 KPa, wherein the container for concentrating under reduced pressure is preferably a thin film evaporator, but can also be a reduced pressure distillation kettle;
C3) adding the concentrated solution subjected to the reduced pressure concentration in the step C2) into a thin film evaporator, and performing reduced pressure evaporation at the temperature of 130-160 ℃ and the pressure of 0.1-1 KPa;
C4) adding the residue (shown in figure 1, which contains BHET monomer, BHET dimer and BHET trimer) subjected to reduced pressure evaporation in the step C3) into a short-path distiller, rectifying at the temperature of 150-200 ℃ and the pressure of 1-10 Pa, collecting the distillate which is colorless transparent liquid, crystallizing at normal temperature to obtain white solid which is high-purity BHET monomer (the color value L is 97.24, the b value is 1.21, the HPLC purity is 99.8%, and the HPLC analysis spectrogram shown in figure 2 is shown in detail; moreover, the obtained white solid is BHET monomer as can be proved by the nuclear magnetic resonance analysis spectrogram shown in FIG. 3);
D) firstly adding a high-purity BHET monomer into a pre-polycondensation reaction kettle I, adding ethylene glycol antimony catalyst, wherein the using amount of the catalyst is 0.01-0.03% of the mass of the high-purity BHET monomer, then stirring and reacting for 1-1.5 hours at 265-270 ℃ under the pressure of 8-12 KPa in the kettle, then introducing the reaction liquid into a pre-polycondensation reaction kettle II, stirring and reacting for 2-2.5 hours at 272-275 ℃ under the pressure of 1-1.5 KPa in the kettle, finally introducing the reaction liquid into a final polycondensation reaction kettle, stirring and reacting for 2-2.5 hours at 278-282 ℃ under the pressure of 100-400 Pa in the kettle, obtaining a regenerated PET melt, and cooling, granulating and drying to obtain the high-purity regenerated PET slice.
The results of the test on the recycled PET polyester chip obtained according to the present invention are shown in the following table, referring to the test analysis method of the virgin PET polyester chip:
the results of the above table test show that: the method can obtain the recycled PET polyester product which is comparable to the original PET polyester excellent product index, can be used in the application with high requirement and high added value, has important significance and value for realizing the recycling of the waste PET polyester in the true sense, and has significant progress compared with the prior art.
Comparative example
The residue obtained after evaporation under reduced pressure of example step C3) (visible from fig. 1: the residue contained 83.82% of BHET monomer, 14.43% of BHET dimer, and 1.75% of BHET trimer); the residue was subjected to conventional distillation under reduced pressure at a vapor pressure of 5Pa and a temperature of 190 c, and HPLC analysis was carried out on the collected fraction (colorless transparent liquid which does not crystallize at ordinary temperature and remains colorless transparent liquid) under the HPLC analysis conditions described in the examples, and a detailed map is shown in fig. 4, as can be seen from fig. 4: no BHET substance peak was observed in the HPLC analysis spectrum, and the obtained colorless transparent liquid was confirmed to be ethylene glycol by the nuclear magnetic resonance analysis spectrum shown in fig. 5, indicating that the BHET monomer could not be obtained at all in the fraction after the conventional reduced pressure distillation of the residue of the same composition (the content of the BHET monomer in the residue was 83.82%, the content of the BHET dimer was 14.43%, and the content of the BHET trimer was 1.75%).
Further intrinsic viscosity and terminal carboxyl detection of the sample before and after distillation can be known as follows:
from the above detection results, it can be seen that: after the residue after the reduced pressure evaporation is subjected to the conventional reduced pressure distillation for 1 hour, the intrinsic viscosity of the residue rises from 0.0567dL/g to 0.1661dL/g, and the terminal carboxyl groups rise from 20.95mol/t to 53.13mol/t, which indicates that the residue has undergone a polycondensation reaction in the conventional reduced pressure distillation and cannot achieve the purpose of purifying the BHET monomer at all.
Combining the above examples and comparative examples, it can be seen that: the invention unexpectedly obtains the high-purity BHET monomer with the HPLC purity of 99.8 percent by adopting a purification treatment method combining reduced pressure concentration with reduced pressure evaporation in a film evaporator and rectification in a short-path distiller for BHET alcoholysis liquid, thereby directly carrying out polycondensation to prepare the high-purity regenerated PET polyester without ester exchange, simplifying the recovery and regeneration process of the waste PET polyester, obviously reducing the use of organic solvent, obviously reducing the energy consumption and cost, breaking through the bottleneck that the BHET is difficult to decolor and purify, leading the color value b value of the regenerated PET polyester to be within 1.0 +/-2.0, obtaining the regenerated PET polyester product which is in a good index with the primary PET polyester, being comparable with the source of the waste PET polyester raw material, being easy to realize large-scale production, leading the regenerated PET product to be used in high-requirement and high-added-value application, and having important significance and value for realizing the regeneration cycle in the sense of the waste PET polyester, a significant advance over the prior art has occurred.
Finally, it should be pointed out here that: the above is only a part of the preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention, and the insubstantial modifications and adaptations of the present invention by those skilled in the art based on the above description are intended to be covered by the present invention.
Claims (7)
1. A method for preparing high-purity recycled PET polyester by using waste PET polyester comprises the following specific steps:
A) carrying out crushing, washing and drying pretreatment on the waste PET polyester;
B) carrying out alcoholysis on the pretreated waste PET polyester in ethylene glycol to obtain BHET alcoholysis liquid;
C) purifying the BHET alcoholysis solution to obtain a high-purity BHET monomer with the HPLC purity of more than 99.0%;
D) carrying out pre-polycondensation reaction and final polycondensation reaction on the high-purity BHET monomer to obtain high-purity regenerated PET polyester;
characterized in that the purification treatment in step C) comprises the following operations:
C1) filtering the BHET alcoholysis solution obtained in the step B) to remove insoluble substances in the solution;
C2) concentrating the filtrate obtained in the step C1) under reduced pressure at 100-140 ℃ and 1-10 KPa;
C3) adding the concentrated solution subjected to the reduced pressure concentration in the step C2) into a thin film evaporator, and performing reduced pressure evaporation at the temperature of 130-160 ℃ and the pressure of 0.1-1 KPa;
C4) and C3), adding the residue after reduced pressure evaporation in the step C3) into a short-path distiller, rectifying at the temperature of 150-200 ℃ and the pressure of 1-10 Pa, and crystallizing the collected fraction at normal temperature to obtain a white solid, namely the high-purity BHET monomer with the HPLC purity of more than 99.0%.
2. The method for preparing high-purity recycled PET polyester by using waste PET polyester as claimed in claim 1, which is characterized in that: the drying in the step A) means that the water content of the waste PET polyester is less than or equal to 3 percent.
3. The method for preparing high-purity recycled PET polyester by using waste PET polyester as claimed in claim 1, wherein the alcoholysis process in step B) is as follows:
putting Ethylene Glycol (EG) and the pretreated waste PET polyester particles into an alcoholysis reaction kettle according to the mass ratio of (1-3) to 1, then putting a zinc acetate catalyst with the mass of 0.1-0.5% of the mass of the waste PET polyester particles, heating to 190-230 ℃, controlling the pressure in the alcoholysis reaction kettle to be 0.1-0.5 MPa, and carrying out alcoholysis reaction for 2-6 hours.
4. The method for preparing high-purity recycled PET polyester by using waste PET polyester as claimed in claim 1, which is characterized in that: the concentration under reduced pressure described in step C2) is carried out in a thin-film evaporator.
5. The method for preparing high-purity recycled PET polyester by using waste PET polyester as claimed in claim 1, wherein the pre-polycondensation reaction in step D) is carried out under the following conditions: under the action of ethylene glycol antimony catalyst, firstly stirring and reacting for 1-1.5 hours at 265-270 ℃ and under the pressure of 8-12 KPa in the kettle, and then stirring and reacting for 2-2.5 hours at 272-275 ℃ and under the pressure of 1-1.5 KPa in the kettle.
6. The method for preparing high-purity recycled PET polyester by using waste PET polyester according to claim 1, wherein the final polycondensation reaction in the step D) is carried out under the following conditions: stirring and reacting for 2-2.5 hours at 278-282 ℃ and the pressure in the kettle of 100-400 Pa.
7. The method for preparing high-purity recycled PET polyester using waste PET polyester according to any one of claims 1 to 6, wherein: the waste PET polyester comprises at least one of waste PET bottles, PET packaging sheets, PET fibers, PET textiles and PET bubble materials.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115283423A (en) * | 2022-08-01 | 2022-11-04 | 江西龙一再生资源有限公司 | Waste polyester depolymerization treatment system |
| CN115894223A (en) * | 2022-08-26 | 2023-04-04 | 东华大学 | Chemical recovery method for waste PET (polyethylene terephthalate) products by using BHET (BHET) crystal phase change property |
| CN116284710A (en) * | 2023-05-22 | 2023-06-23 | 广东绿王新材料有限公司 | Method for preparing polyester chips by chemical recycling of waste polyester fibers |
| CN117510326A (en) * | 2023-11-02 | 2024-02-06 | 浙江佳人新材料有限公司 | Waste textile recycling depolymerization liquid concentration process |
| WO2024045639A1 (en) * | 2022-08-31 | 2024-03-07 | 科泽新材料股份有限公司 | Method for preparing pent copolyester |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1511821A (en) * | 1999-08-04 | 2004-07-14 | ��ʽ���簮������� | Bis-beta-hydroxyethyl terephthalate production process and purification process |
| CN104710601A (en) * | 2015-01-23 | 2015-06-17 | 广东树业环保科技股份有限公司 | Method for preparing highly pure PET slice through decoloring recovery of waste PET materials, and product thereof |
| CN108641120A (en) * | 2018-08-14 | 2018-10-12 | 上海聚友化工有限公司 | A kind of method and its recovery system of the recycling of waste and old polyester textile |
-
2020
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1511821A (en) * | 1999-08-04 | 2004-07-14 | ��ʽ���簮������� | Bis-beta-hydroxyethyl terephthalate production process and purification process |
| CN104710601A (en) * | 2015-01-23 | 2015-06-17 | 广东树业环保科技股份有限公司 | Method for preparing highly pure PET slice through decoloring recovery of waste PET materials, and product thereof |
| CN108641120A (en) * | 2018-08-14 | 2018-10-12 | 上海聚友化工有限公司 | A kind of method and its recovery system of the recycling of waste and old polyester textile |
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| CN115283423A (en) * | 2022-08-01 | 2022-11-04 | 江西龙一再生资源有限公司 | Waste polyester depolymerization treatment system |
| CN115894223A (en) * | 2022-08-26 | 2023-04-04 | 东华大学 | Chemical recovery method for waste PET (polyethylene terephthalate) products by using BHET (BHET) crystal phase change property |
| WO2024045639A1 (en) * | 2022-08-31 | 2024-03-07 | 科泽新材料股份有限公司 | Method for preparing pent copolyester |
| CN116284710A (en) * | 2023-05-22 | 2023-06-23 | 广东绿王新材料有限公司 | Method for preparing polyester chips by chemical recycling of waste polyester fibers |
| CN116284710B (en) * | 2023-05-22 | 2023-11-24 | 广东绿王新材料有限公司 | Method for preparing polyester chips by chemical recycling of waste polyester fibers |
| CN117510326A (en) * | 2023-11-02 | 2024-02-06 | 浙江佳人新材料有限公司 | Waste textile recycling depolymerization liquid concentration process |
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