Multilayer Polyester Container Yellowing Suppression
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Solution Overview
Problem
Multilayer containers made from polyester and polyamide resins face issues with yellowing during recycling, which affects their commercial value and processing stability, and existing methods do not effectively suppress this yellowing while maintaining gas barrier properties.
Innovation Solution
Incorporating an amino group-containing compound, such as anthranilamide or nylon 6I/6T, into the polyester resin composition layer to prevent yellowing by trapping acetaldehyde and preventing its reaction with polyamide resin, thereby maintaining the gas barrier properties and transparency of the container.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyamide resin is added to polyester resin to improve gas barrier property, then oxygen and carbon dioxide barrier properties are enhanced, but yellowing occurs during thermal processing and recycling
Solution Approach 1:
A polyol compound is introduced as an intermediary substance between polyester resin and polyamide resin. This polyol compound reacts with excess isocyanate groups from the polyamide resin, preventing the yellowing reaction while maintaining the gas barrier properties provided by the polyamide resin.
Solution Approach 2:
The invention converts the harmful excess isocyanate groups that cause yellowing into a beneficial function by having them react with the polyol compound to form additional crosslinks. This transforms the yellowing-causing agents into additional strengthening crosslinks that improve mechanical properties without causing discoloration.
2Strength
If crosslinking is increased to enhance mechanical strength and heat resistance, then processing stability improves, but yellowing is more likely to occur
Solution Approach 1:
The polyol compound serves as a mediator that enables additional crosslinking through reaction with excess isocyanate groups, providing enhanced mechanical strength and heat resistance without triggering the yellowing reaction that would result from direct polyester-polyamide thermal interaction.
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 proposed solution effectively suppresses yellowing of regenerated polyester resin during recycling, enhances gas barrier properties, and maintains the transparency and commercial value of the packaging container.
Implementation Method 1
Incorporating an amino group-containing compound, such as anthranilamide or nylon 6I/6T, into the polyester resin composition layer to prevent yellowing by trapping acetaldehyde
Data Source
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AI summary
An object of the present invention is to provide a multilayer container in which yellowing of a regenerated polyester resin at the time of recycle is suppressed and a method for producing the same as well as a method for producing a single-layer container. Furthermore, another object of the present invention is to provide a method for producing a regenerated polyester resin from the foregoing multilayer container and single-layer container. The multilayer container of the present invention includes at least one polyester resin composition layer containing a polyester resin (X) and an amino group-containing compound (A) having a yellowing-suppressing ability; and at least one polyamide resin layer containing a polyamide resin (Y).