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Method for preparing waste polyester particles with micropores through gas foaming

A technology of gas foaming and waste polyester, applied in the direction of plastic recycling and recycling technology, can solve problems such as residues, and achieve the effects of reducing impurities, increasing the contact surface and improving the yield.

Active Publication Date: 2020-02-21
ZHEJIANG SCI-TECH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the added chemical blowing agent will inevitably have residues, which leads to the need to consider removing the chemical blowing agent in the subsequent impurity removal process

Method used

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  • Method for preparing waste polyester particles with micropores through gas foaming

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Add the recovered polyester (PET) bottle flakes, polyester (PET) slurry blocks, etc. into the screw granulator, and blow nitrogen gas together for melt granulation. The heating temperature of each zone of the screw granulator is 250°C, 260°C, 270°C, 280°C, 275°C, 275°C, 270°C, the feed percentage of the screw is 15%, the speed is 45rpm, the pressure is 75Mpa, the gas input It is 0.1 L / min, and the filter specification is 100 mesh. Nitrogen gas is selected for the formation of micropores, and the gas flow rate is 0.1L / min. The position of the gas is the fourth heating zone of the screw. After the extruded strip passes through the cooling water tank, the micropores are formed stably, and finally cut into pellets.

[0028] The micropore-containing waste polyester granules prepared by the waste polyester granulation step above have an average cell diameter of 115 μm and a relative density of 0.70.

[0029] Put the waste polyester (PET) pellets containing micropores into a ...

Embodiment 2

[0035] The recycled and sorted polyester (PET) film and polyester (PET) fiber products (curtains, carpets, clothing, etc.) are densified by thermal friction molding process at a temperature of 220°C, a pressure of 3MPa, and a time of 10 minutes. Foam material is formed, and then the foam material is melted and granulated in a twin-screw extruder. The heating temperature of each zone of the twin-screw extruder is 265°C, 270°C, 275°C, 280°C, 275°C, 270°C, 270°C, the feeding percentage of the screw is 30%, the screw speed is 60rpm, and the pressure is 4.5Mpa. The device specification is 200 mesh. Micropore formation selective access to CO 2 , the gas feed rate is 0.3 L / min, and the feed position is the fourth heating zone of the screw. After the granulation is completed, the micropore formation is stable after passing through the cooling water tank.

[0036] The microporous waste polyester granules prepared by the microporous waste polyester granulation step have a cell size of...

Embodiment 3

[0043] After cleaning and drying the recycled and sorted polyester (PET) bottle flakes and polyester (PET) pulp blocks, they are melted and granulated in a twin-screw extruder. The heating temperature of each zone of the twin-screw extruder is 260°C, 270°C, 280°C, 285°C, 275°C, 270°C, 270°C, the screw feeding percentage is 45%, the speed is 80rpm, and the pressure is 75Mpa. The percentage is 12%, the screw speed is 65rpm, the pressure is 7.5Mpa, and the filter device specification is 100 mesh. Micropore formers select N 2 :CO 2 It is a 1:1 mixed gas, and the gas feed rate is 0.5 L / min.

[0044] The average cell diameter of the microporous waste polyester granules prepared by the microporous waste polyester granulation step is 113 μm, and the relative density is 0.60. For the average cell diameter test, the average value of 100 average cell diameters was continuously measured by an optical microscope as the cell diameter. The test method for the relative density of micropor...

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Abstract

The invention relates to the field of waste polyester recycling, in particular to a method for preparing waste polyester particles with micropores through gas foaming. The method comprises the following steps: 1) classifying recycled waste polyester according to color, quality and form; 2) carrying out melt granulation in a twin-screw extruder, introducing gas in the granulation process, and forming micropores in the surfaces and the interiors of the waste polyester particles after cooling; the average pore diameter of the waste polyester particles is 30-200 <mu>m, and the relative density is0.3-0.7. According to the method, the waste polyester particles contain a large number of micropore structures and are high in stacking density, the contact surface of a solvent and the solid particles is increased, the depolymerization efficiency is improved, impurities can be prevented from being brought in, and the product final performance is improved.

Description

technical field [0001] The present application relates to the field of regeneration and utilization of waste polyester, in particular to a method for preparing micropore-containing waste polyester particles by gas foaming. Background technique [0002] Polyethylene terephthalate (PET) is polymerized from terephthalic acid or dimethyl terephthalate and ethylene glycol. Due to its good physical and chemical stability and processability, it is widely used in textiles, clothing, decoration, food packaging and other fields. However, due to the strong chemical inertness of PET under natural conditions, it is difficult to be biodegraded, and a large amount of waste polyester has caused great pressure on the environment. Therefore, recycling waste polyester products can achieve effective recycling of resources and reduce environmental pollution. Pollution has become an important issue in the polyester industry. [0003] At present, there are mainly physical and chemical methods fo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J9/12C08J11/24C08L67/02
CPCC08J9/122C08J9/0061C08J11/24C08J2203/06C08J2367/02C08J2300/30C08J2203/182C08J2205/044Y02W30/62
Inventor 王秀华王勇花泓静温馨邓倩倩曹宇恒
Owner ZHEJIANG SCI-TECH UNIV