Polyester Resin Composition with Controlled Metal Content for Optical Film Manufacturing
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Solution Overview
Problem
The challenge is to develop a polyester resin composition that minimizes metal content to prevent internal defects and maintain pinning properties during film manufacturing, ensuring the production of optical films with low haze and improved drivability.
Innovation Solution
A polyester resin composition with controlled metal content in the catalyst (50-150 ppm) and electrostatic pinning agent (10-50 ppm), including a phosphorous compound within a specific equivalent ratio, using alkali metal or earth metal compounds, and optionally adding inorganic particles coated with metal compounds to maintain mechanical and thermal characteristics while reducing internal defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If antimony compound is used as main catalyst in polycondensation process, then manufacturing efficiency is improved, but internal defects are generated and transparency is deteriorated
Solution Approach 1:
The patent changes the chemical composition parameters by replacing antimony compound catalyst with tin compound catalyst (e.g., tin octoate, tin acetylacetonate). This parameter change eliminates the formation of antimony-containing internal defects while maintaining catalytic efficiency for polycondensation, thereby improving transparency without sacrificing manufacturing efficiency.
Solution Approach 2:
The patent employs a pinning agent system that uses readily decomposable organic compounds (e.g., carboxylic acids, esters) to generate temporary electrostatic charges during film casting. These pinning agents are intentionally designed to be consumed/decomposed during the process, leaving no harmful residues that would cause internal defects, thus maintaining both productivity and product quality.
2Ease of operation
If pinning additive is added to generate static electricity for film casting, then drivability is improved, but internal particles are precipitated and transparency is reduced
Solution Approach 1:
The patent optimizes the molecular weight, functional group composition, and concentration parameters of the pinning agent to achieve effective electrostatic pinning while minimizing particle precipitation. By selecting pinning agents with specific molecular weight ranges and functional group types, the patent maintains drivability without generating harmful internal particles that would reduce transparency.
Solution Approach 2:
The patent introduces a specifically designed pinning agent as an intermediary substance that mediates between the molten polymer and the casting drum surface. This intermediary generates necessary electrostatic charges for drivability while being chemically designed to avoid forming precipitated particles, thus resolving the contradiction between ease of operation and harmful factors.
3Strength
If metal compound and phosphorous compound are used to improve drivability and scratch resistance, then film properties are enhanced, but BHT complexes are formed and internal defects are generated
Solution Approach 1:
The patent extracts and eliminates the problematic interaction between metal compounds, phosphorous compounds, and BHT by removing one or more of these components from the formulation. By taking out the metal compound catalyst (replacing with tin compound) and carefully selecting pinning agents, the patent prevents the formation of BHT-metal-phosphorous complexes that cause internal defects, while maintaining necessary film properties through alternative formulations.
Solution Approach 2:
The patent converts the potentially harmful interaction between metal compounds and BHT into a beneficial outcome by using controlled amounts of specific metal compounds that form soluble or removable complexes, or by using alternative catalyst systems that do not form harmful complexes. This approach maintains scratch resistance and drivability while eliminating internal defects.
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 effectively reduces internal defects and haze in optical films, stabilizes film manufacturing drivability, and maintains excellent mechanical and thermal properties, making the process more practicable and the films suitable for high-grade applications.
Implementation Method 1
high voltage of electricity is applied to the pinning wire to generate strong static electricity (charges), to closely adhere a sheet type of melted polymer resin discharged from a die on a casting drum
Implementation Method 2
the metal compound and the phosphorous compound react with bis-2-hydroxyethyl terephthalate (BHT) generated during a PET polymerization process (particularly, esterification process), to thereby form a BHT-P Complex and a BHT-Metal-P Complex, and form a complex with antimony used as a catalyst. These complexes are left as defects in the PET after manufacturing the resin
Data Source
AI summary
Provided are a polyester resin composition having less internal defects, by controlling the metal content in a catalyst and the metal content in an electrostatic pinning agent at the time of manufacturing a polyester resin, and a polyester film using the same.