Hydrolysis Resistant Polyester Films Using Glycidyl Esters
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Solution Overview
Problem
Polyester films face hydrolysis degradation under humid conditions and elevated temperatures, leading to reduced mechanical properties and processability issues due to the use of traditional hydrolysis stabilizers, which often result in toxic by-product emission, gel formation, and profile defects.
Innovation Solution
A biaxially oriented polyester film using a glycidyl ester of a branched monocarboxylic acid as a hydrolysis stabilizer, which reacts with polyester end-groups to enhance hydrolysis resistance without toxic by-product formation, maintaining mechanical and optical properties and improving film uniformity and processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional hydrolysis stabilizers are used to improve hydrolysis resistance, then hydrolysis resistance is improved, but toxic by-products are emitted and mechanical properties deteriorate
Solution Approach 1:
The invention changes the chemical structure parameters of the stabilizer by using glycidyl esters of branched monocarboxylic acids with specific carbon chain lengths (5-50 carbons). This structural modification allows the stabilizer to function effectively while avoiding toxic by-product formation during processing and use.
Solution Approach 2:
The invention creates a composite system where the glycidyl ester stabilizer works synergistically with the polyester matrix. The stabilizer integrates into the polymer structure through chemical reaction, forming a composite material system that provides hydrolysis protection without the harmful effects of traditional additives.
2Reliability
If traditional hydrolysis stabilizers are used to improve hydrolysis resistance, then hydrolysis resistance is improved, but mechanical properties and processability deteriorate
Solution Approach 1:
The invention optimizes the molecular weight and structural parameters of the glycidyl ester stabilizer to ensure compatibility with the polyester matrix. The specific carbon chain length (5-50 carbons) and branched structure are carefully selected to maintain mechanical properties while providing effective hydrolysis protection.
3Reliability
If hydrolysis stabilizers are incorporated into polyester films, then hydrolysis resistance is improved, but profile defects and gel formation occur
Solution Approach 1:
The invention changes the chemical reactivity parameters of the stabilizer by using glycidyl esters with controlled molecular weight and structure. This reduces excessive reactivity that would cause gel formation, while still providing sufficient reactivity to cap end-groups and prevent hydrolysis. The result is improved film uniformity without profile 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 provides improved hydrolysis resistance, reduced profile defects, and enhanced film uniformity and processability, allowing for the use of higher reclaim polyester while minimizing thermal degradation and gel formation, making it suitable for applications like photovoltaic cells.
Implementation Method 1
a glycidyl ester of a branched monocarboxylic acid as a hydrolysis stabiliser, which reacts with polyester end-groups to enhance hydrolysis resistance
Implementation Method 2
polyester films are susceptible to hydrolytic degradation... improved hydrolysis resistance... under humid conditions and/or elevated temperatures
Data Source
AI summary
A biaxially oriented polyester film including polyethylene terephthalate (PET) and at least one hydrolysis stabilizer selected from a glycidyl ester of a branched monocarboxylic acid, wherein the monocarboxylic acid has from 5 to 50 carbon atoms, wherein the hydrolysis stabilizer is present in the film in the form of its reaction product with at least some of the end-groups of the polyester; a process for making the same; and use of the film as a layer in a photovoltaic cell.