Polyester Multi-Layer Film Oligomer Migration Control
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Solution Overview
Problem
Polyester films experience oligomer migration to the surface during high-temperature processes, leading to reduced transparency and productivity due to the blooming phenomenon and contamination.
Innovation Solution
A polyester multi-layer film with a substrate layer and a skin layer containing polyester and an organic phosphorus compound, where the film satisfies specific equations regarding oligomer concentration and haze change after heat treatment, effectively suppressing oligomer generation and migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-temperature process is used for manufacturing displays, then productivity and mechanical strength are improved, but oligomers migrate to the surface causing blooming phenomenon and reducing transparency
Solution Approach 1:
The patent changes the chemical composition parameters of the polyester by controlling the molar ratio of cyclic oligomers to specific linear oligomers (nC3/nC4) within a predetermined range (0.05-5.0). This parameter control suppresses oligomer migration to the surface even at high temperatures, preventing blooming while maintaining manufacturing productivity.
Solution Approach 2:
The patent creates a composite polyester structure by controlling the molecular weight distribution and oligomer composition, specifically maintaining a balance between cyclic oligomers (C3) and linear oligomers (C4). This composite approach at the molecular level prevents phase separation and surface migration of oligomers during high-temperature processing.
2Object-affected harmful factors
If solid-state polymerization is used to reduce oligomer content, then transparency is improved, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent performs preliminary control of oligomer composition during the main polymerization process by controlling the nC3/nC4 ratio. This preliminary action prevents excessive oligomer formation before solid-state polymerization, reducing the need for extended polymerization treatments and simplifying the overall process while maintaining transparency.
Solution Approach 2:
The patent optimizes polymerization parameters including temperature, catalyst type, and reaction time to achieve the target nC3/nC4 ratio. By controlling these parameters during melt polymerization, the need for aggressive solid-state polymerization is reduced, simplifying the manufacturing process.
3Object-affected harmful factors
If high-molecular-weight polyester is used to suppress oligomer migration, then transparency is improved, but manufacturing cost increases due to extended polymerization time
Solution Approach 1:
The patent changes the approach from increasing molecular weight to controlling oligomer composition ratio. By maintaining the nC3/nC4 ratio within 0.05-5.0, the patent achieves suppression of oligomer migration without requiring excessively high molecular weights, thus reducing polymerization time and associated costs.
Solution Approach 2:
The patent applies local quality control by specifically targeting the composition of migratory oligomers (cyclic vs linear) rather than uniformly increasing all polymer molecular weights. This localized compositional control prevents migration while avoiding the time and cost penalties of extensive polymerization.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution maintains the transparency and visibility of the film by preventing oligomer migration, even at high temperatures, while also reducing manufacturing costs and increasing productivity by minimizing contamination.
Implementation Method 1
a polyester multi-layer film with a substrate layer including polyester and a skin layer located on at least one surface of the substrate layer and including polyester and an organic phosphorus compound
Data Source
AI summary
A polyester multi-layer film of the present invention comprises: a substrate layer comprising polyester; and a skin layer located on at least one surface of the substrate layer, wherein the polyester multi-layer film suppresses generation of oligomers in the film and migration to the surface even in a high-temperature treatment process by satisfying a predetermined correlation between the concentration of cyclic oligomers in the film and a haze value before and after heat treatment, thereby maintaining transparency and visibility of the film in the long term.