废弃偏光片中PET膜的脱胶回收方法

Degumming and Recovery Method of PET Film in Waste Polarizing Film

偏光片是液晶显示器的核心组件。随着液晶显示技术的发展,偏光片的用量越来越大,随之也产生了大量废弃偏光片。这些废弃偏光片属于有机废料,由多层高分子膜紧密粘结而成,其中作为保护膜和离型膜的外层PET膜材料含量较高,属于可再生塑料,回收再利用价值较高,但由于这些PET膜上含有不易脱除的特殊胶黏剂层,导致其回收利用难度大。目前,行业内一般采用焚烧发电(环境污染)、热解成小分子(成本高)或降级为混合多层膜料(附加值低)的方式将废弃偏光片回收利用,但这些方法均不具备工业化应用前景。本研究针对废弃偏光片中PET膜上的特殊胶黏剂层,设计了高效环保的脱胶试剂配方(乙二醇+氢氧化钠),实现了废弃偏光片中PET膜层的高效脱胶回收,为后续废弃偏光片的工业化回收利用做好了技术铺垫。

Polarizing film is the core component of LCD.With the development of liquid crystal display technology,the amount of polarizing film is increasing,and a large number of discarded polarizing film are also produced.These waste polarizing film belong to organic wastes,which are made of multilayer polymer film tightly bonded.The outer PET film material content as protective film and release film is high,which belongs to renewable plastic and has high recycling value.However,because these PET films contain special adhesive layer that is not easy to remove,it is difficult to recycle them.At present,in the industry,waste polarizers are generally recycled by incineration for power generation(environmental pollution),pyrolysis into small molecules(high cost)or degradation to mixed multilayer film materials(low added value),but these methods do not have industrial application prospects.This research aims at the special adhesive layer on the PET film in the waste polarizing film,and designs an efficient and environmentally friendly degumming reagent formula(ethylene glycol+sodium hydroxide),which realizes the efficient degumming and recycling of the PET film in the waste polarizing film,and lays a technical foundation for the industrial recycling of the waste polarizer.