Recycled Polyester Film Composition for Thermal Stability
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Solution Overview
Problem
Existing methods for recycling polyester resins face issues of degradation and reduced molecular weight due to coloring, which affect the thermal stability and recyclability of polyester films, particularly when using antimony, titanium, or germanium compounds as polymerization catalysts.
Innovation Solution
Incorporating an aluminum compound and a phosphorus compound into recovered polyester resins, along with specific intrinsic viscosity and elemental content, to produce a polyester film with improved thermal stability and recyclability, using a method that includes mixing and polycondensation steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If recovered polyester resin is used as raw material for film production, then recycling efficiency is improved, but coloring and decrease in molecular weight occur due to degradation
Solution Approach 1:
The patent applies preliminary action by adding a specific antioxidant package (hindered phenol compound at 0.01-0.1 wt% and phosphite compound at 0.01-0.1 wt%) to the recovered polyester resin before film production. This preventive measure protects the resin from degradation during subsequent processing, maintaining molecular weight stability while enabling high recycling efficiency
Solution Approach 2:
The patent changes the chemical parameter composition of the recovered polyester resin by introducing specific compounds (hindered phenol and phosphite) in controlled amounts. This parameter modification prevents oxidation and hydrolysis during processing, thereby maintaining intrinsic viscosity and molecular weight while maximizing the use of recovered material
2Productivity
If recovered polyester resin is used as raw material for film production, then recycling efficiency is improved, but coloring occurs due to degradation
Solution Approach 1:
The patent applies preliminary action by pre-treating the recovered polyester resin with an optimized antioxidant package (hindered phenol compound at 0.01-0.1 wt% and phosphite compound at 0.01-0.1 wt%) before film production. This preventive protection prevents oxidative degradation that causes yellowing and coloration during subsequent high-temperature processing
Solution Approach 2:
The patent converts the potentially harmful effect of thermal processing (which causes coloring) into a beneficial outcome by using the antioxidant additives to protect the resin. The processing heat that would normally cause degradation is instead utilized for film formation while the additives prevent coloring, transforming a harmful process into a controlled beneficial one
3Reliability
If hindered phenol compound is added to improve thermal oxidation stability, then thermal stability is improved, but physical characteristics degradation still occurs during recycling
Solution Approach 1:
The patent merges two different protective mechanisms by combining a hindered phenol compound (for thermal oxidation stability) with a phosphite compound (for hydrolysis prevention and molecular weight protection). This combination provides comprehensive protection that maintains both thermal stability and physical characteristics including intrinsic viscosity and mechanical properties during recycling
Solution Approach 2:
The patent creates a composite protective system by combining two types of chemical additives (hindered phenol and phosphite compounds) in specific proportions. This composite approach provides synergistic protection against multiple degradation mechanisms simultaneously, preserving both thermal stability and physical characteristics better than either additive alone
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 method results in a polyester film with reduced degradation, lower molecular weight, and increased recycling efficiency, allowing for higher proportions of recovered polyester use while minimizing environmental impact.
Implementation Method 1
a catalyst containing an aluminum compound and a phosphorus compound having hindered phenol structure as described in Patent Documents 3 and 4 is used for polyesters to improve the transparency and the thermal stability of polyesters
Implementation Method 2
the polyester resin (B) is obtained by polycondensation of a raw material containing bis-2-hydroxyethyl terephthalate obtained by decomposing a polyester resin
Data Source
AI summary
A method produces a polyester film with high recycling efficiency. The method includes mixing a recovered polyester resin (A) with a polyester resin (B) containing an aluminum compound and a phosphorus compound, wherein the polyester resin (A) satisfies (1) to (3) and the polyester resin (B) satisfies (4):(1) the polyester resin (A) contains at least one element selected from antimony element, titanium element, and germanium element,(2) a total content of the antimony element, the titanium element, and the germanium element in the polyester resin (A) is 2 to 500 ppm by mass,(3) the polyester resin (A) has an intrinsic viscosity of 0.5 to 0.8 dl/g, and(4) the polyester resin (B) is obtained by polycondensation of a raw material containing bis-2-hydroxyethyl terephthalate obtained by decomposing polyester resin.