PVA Separation

Polarizing films using iodine are widely used for liquid crystal displays, liquid crystal televisions, mobile phones, and PDAs because of their high transmittance and high polarization (high contrast). The main manufacturing processes are divided into five stages: TCA film processing, PVA film drawing, functional film coating, release film attachment, and aging & cutting.

Project Overview

LG Chemical, Polaroid Film Production

During the PVA film drawing process, potassium iodide (KI) solution and boric acid are continuously discarded but there is a great need for concentration and reuse because of the limited nature of these raw materials. The figure below depicts how KI solution, boric acid, and PVA are separated after PVA film drawing process. 

  <Figure 1. Potassium Iodine Reuse Method>

<Figure 1. Potassium Iodine Reuse Method>


Goals

Use FMX to improve upon PVA removal process due to its high removal rate and durability. 


Challenges

Conventionally, PVA is removed by cartridge filters, but is insufficient because it had to be frequently replaced. The PVA removal rate was less than 12%.


Solution

Utilize FMX rotating blade technology to suppress fouling and facilitate stable operation without the need for replacing membrane frequently. 

  &lt;Figure 2. FMX and Cartridge Filter Comparison&gt;

<Figure 2. FMX and Cartridge Filter Comparison>


Results

BKT's FMX was able to improve upon PVA removal rate by more than 30% and is expected to increase total production yield by more than 5%.

In 2017, LG Chemical purchased one FMX unit for their factory in South Korea. Satisfied with their results, LG Chemical put in an order for additional FMX units for their Nanjing factory in China. 

 
 
 
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