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Method and product for preparing high-purity pet slices through decolorization and recycling of waste pet materials

A waste and high-purity technology, applied in the field of polymers, can solve the problems of high equipment requirements, low recovery efficiency, high energy consumption, etc., and achieve the effects of reducing solvent demand, improving recycling yield, and saving recycling costs

Active Publication Date: 2016-08-24
SHUYE ENVIRONMENTAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The chemical method is to degrade the PET material under the action of heat and chemical reagents to form low-molecular products, which can be further utilized, such as monomers can be repolymerized, and oil products can be further processed, but this method requires high temperature and high pressure, which requires a lot of equipment. High conditions, high energy consumption, and harsh conditions make it difficult to achieve large-scale operations; the physical method is a recycling technology for reprocessing waste PET through cutting, crushing, heating and melting, but the performance of recycled PET is much higher than that of new materials. Reduced, and contains a lot of impurities, the application value is greatly reduced
Printed PET film can not be processed and recycled due to easy foaming, broken particles, blackened color and odor in the physical treatment, which is still a blank area in technology
[0005] The existing Chinese patent document CN1061420A discloses a recycling method for waste plastics. In this method, the waste plastics are dissolved in a solvent at a temperature of 80-200° C., decolorized and filtered for multiple times to obtain recycled products with good purity and high quality. products; however, the recycling process needs to be carried out at a high temperature of 80-200°C, which is difficult to operate and consumes high energy consumption, and will cause some plastics to degrade into small molecular products, which will increase the recycling process of subsequent recycled materials and reduce the Actual Recovery Efficiency

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Example 1 The method and products thereof for preparing high-purity PET chips by decolorizing waste PET materials provided in this example include the following steps:

[0038] (1) Preparation of PET low molecular solution:

[0039] Put the collected waste polyethylene terephthalate PET waste film and BHET powder into the kneader in a mass ratio of 3:2-9:1, control the temperature at 200-260°C, mix and crush , Disperse for 10-100min, PET low molecular solution can be obtained;

[0040] (2) Preparation of PET primary solution:

[0041] Put the propylene glycol and the obtained PET low-molecular solution into a closed container at a mass ratio of 1-4:1, and stir and keep warm for 1-4 hours under the conditions of 200-240°C and 0.1-0.4Mpa to obtain PET primary solution;

[0042] (3) Filtration, cooling and crystallization:

[0043] Put the obtained PET primary solution into a filter with a pore size of 10-200 mesh, filter at 120-140°C and normal pressure, remove impuri...

Embodiment 2

[0060] The method and its products for preparing high-purity PET slices provided by the decolorization and recycling of waste PET materials provided in this example are basically the same as in Example 1, except that:

[0061] (1) Add the collected printed waste polyester clothes and BHET powder into the kneader at a mass ratio of 8:2, control the temperature at 230°C, mix, crush, and disperse for 10 minutes to obtain a PET low-molecular solution ;

[0062] (2) Put propylene glycol and the obtained PET low-molecular solution into an airtight container at a mass ratio of 2.5:1, stir and keep warm at 230°C and 0.2Mpa for 3 hours to obtain a PET primary solution;

[0063] (3) Put the obtained PET primary solution into a filter with a pore size of 60 mesh, filter at 130°C and normal pressure, remove impurities, and obtain the initial solution; then cool and crystallize at 30°C, and precipitate to obtain dihydroxy terephthalate Ethyl ester BHET primary cake and propylene glycol; ...

Embodiment 3

[0072] The method and its products for preparing high-purity PET slices by decolorizing and recycling waste PET materials provided in this example are basically the same as those in Examples 1 and 2, except that:

[0073] (1) Add the collected waste magnetic tape film and BHET powder into the kneader at a mass ratio of 7:3, control the temperature at 240°C, mix, crush, and disperse for 55 minutes to obtain a PET low-molecular solution ;

[0074] (2) Put propylene glycol and the obtained PET low-molecular solution into an airtight container at a mass ratio of 3:1, stir and keep warm at 240°C and 0.3Mpa for 2 hours, and obtain the PET primary solution;

[0075] (3) Put the obtained PET primary solution into a filter with a pore size of 80 mesh, filter at 140°C and normal pressure, remove impurities, and obtain the initial solution; then cool and crystallize at 40°C, and precipitate to obtain dihydroxy terephthalate Ethyl ester BHET primary cake and propylene glycol;

[0076] (...

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Abstract

The invention discloses a method for preparing a highly pure PET slice through decoloring recovery of waste PET materials, and the highly pure PET slice prepared through the method. The method comprises the following steps: processing the waste PET materials through a kneader, dissolving the processed waste PET materials in a propylene glycol solution, filtering, cooling for crystallizing, squeezing twice, dissolving, crystallizing to obtain a refined BHET cake, dissolving the refined BHET cake in deionized water, crystallizing, distilling to obtain highly pure BHET powder, and carrying out a condensation polymerization reaction to prepare the highly pure PET slice. The method breaks through the technical problem of most difficult recovery of printing composite films with high content of ink in the waste PET recovery, overcomes a bottleneck that traditional technologies only can be used to recover clean and dried bottle slices and clean waste filaments in fiber plants, greatly reduces the complex degree of an apparatus, reduces the solvent demand, reduces energy consumption, improves the recovery yield and the product purity, reduces the cost, causes no secondary pollution, realizes high recycling of waste plastics, and also realizes industrialized production.

Description

technical field [0001] The present invention relates to the technical field of macromolecules, and relates to a process for recycling waste plastics, in particular to a method for preparing high-purity PET slices through decolorization and recycling of waste PET materials and [0002] products. Background technique [0003] The main sources of waste polyethylene terephthalate (PET) materials are waste materials produced at various stages in the production process of polyester fibers or filaments, waste fiber products made of polyester fibers or filaments, printing Waste PET film and PET sheet before or after printing. Among them, dyed polyester fibers and printed composite films contain a large amount of ink (generally about 10-15wt%), which is difficult to process and almost unmanned, which has become a major problem in the recycling of international waste PET materials; on the other hand, waste PET The material is chemically inert and not easily degraded by air or microo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G63/183C08G63/86
Inventor 林树光
Owner SHUYE ENVIRONMENTAL TECH CO LTD