Polyester Film Fold Holding Layer Design
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Solution Overview
Problem
Conventional polyester films face challenges in achieving a balance between excellent fold holding property, low heat shrinkage, transparency, and aroma retention, with existing solutions either compromising on one or more of these characteristics.
Innovation Solution
A polyester film with a multi-layer structure, where at least one surface layer is a fold holding layer with a specific amorphous component composition, and a heat shrinkage rate of 0-15% when treated in 80°C hot water, ensuring a fold holding angle of 20-70 degrees and haze of 1-12%, while maintaining low thickness unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a polyethylene terephthalate film is reduced in density to improve fold holding property, then fold holding property is improved, but heat shrinkage property deteriorates
Solution Approach 1:
The film is divided into multiple layers with different functions: surface layers contain amorphous components for fold holding, while the core layer uses highly oriented crystalline polyester for dimensional stability. This segmentation allows each layer to optimize its specific function without compromising the other.
Solution Approach 2:
The invention uses a composite structure combining amorphous polyester components (for fold holding) with highly oriented crystalline polyester components (for low shrinkage). The composite material integrates the beneficial properties of both amorphous and crystalline phases to achieve both fold holding and dimensional stability.
2Stability of the object's composition
If paper is used to achieve excellent fold holding property, then fold holding property is improved, but water resistance deteriorates
Solution Approach 1:
The invention changes the material parameter from natural fiber (paper) to synthetic polyester resin, fundamentally altering the material's interaction with water while maintaining fold holding properties through controlled amorphous content and molecular orientation.
3Stability of the object's composition
If cellophane is used to achieve excellent fold holding property, then fold holding property is improved, but product quality consistency deteriorates
Solution Approach 1:
The invention uses synthetic polyester resin that can be uniformly processed into consistent multi-layer structures with controlled amorphous content. The homogeneous material composition and controlled manufacturing process eliminate the quality variations inherent in natural cellophane production.
4Stability of the object's composition
If polyethylene film is used to achieve excellent fold holding property, then fold holding property is improved, but aroma retaining property deteriorates
Solution Approach 1:
The invention changes the material from polyethylene to polyester, altering the chemical properties to improve aroma retention while maintaining fold holding through controlled amorphous content and molecular structure.
Data Source
AI summary
The polyester film is formed with a polyester resin whose main constituent component is ethylene terephthalate. The polyester film has two or more layers that include at least one fold holding layer, which is present on at least one of the film surfaces and has a total of at least one monomer component that can form an amorphous component of 12-30% by mol in all monomer components of the fold holding layer and a difference in amount of an amorphous component of 4-30% by mol obtained by deducting an amount of an amorphous component in a layer other than the fold holding layer from the amount of the amorphous component in the fold holding layer. The polyester film has a fold holding angle of 20-70 degrees and a heat shrinkage rate of 0-15% in the longitudinal and width directions when treated in 80° C. hot water for 10 seconds.