Biaxially Oriented Polyester Film Moldability Heat Resistance
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Solution Overview
Problem
Existing biaxially oriented polyester films for molding lack sufficient moldability, dimensional stability, and heat resistance, particularly at high temperatures, leading to issues such as surface roughening and compromised quality in molded products.
Innovation Solution
A biaxially oriented polyester film with specific storage elastic moduli, stress values, and crystal melting peak temperatures, featuring a laminate structure with defined ethylene glycol and cyclohexane dimethanol content in its layers, optimized for low-temperature moldability and high-temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the storage elastic modulus at high temperature is reduced to improve moldability, then the film can be shaped more easily at low temperature, but the storage elastic modulus at high temperature becomes too low causing surface roughening and quality decline
Solution Approach 1:
The patent applies parameter changes by precisely controlling the storage elastic modulus at different temperatures through specific compositional parameters (ethylene glycol content: 85-95 mol%, cyclohexane dimethanol content: 5-15 mol%). This allows the film to have low storage elastic modulus at molding temperature (100-150°C) for easy shaping, while maintaining high storage elastic modulus at high temperature (≥200°C) to prevent surface roughening and maintain quality.
2Ease of operation
If the storage elastic modulus over a wide temperature range is reduced to improve moldability, then the film exhibits excellent moldability, but the storage elastic modulus in high temperature region becomes low resulting in insufficient heat resistance
Solution Approach 1:
The patent uses parameter changes to achieve different storage elastic modulus characteristics at different temperature ranges by controlling the diol component composition. The specific parameter ranges (ethylene glycol: 85-95 mol%, cyclohexane dimethanol: 5-15 mol%) create a film that is soft and moldable at low temperature but maintains structural integrity and high storage elastic modulus at high temperature, thus achieving both good moldability and heat resistance.
3Ease of operation
If the film is designed for low temperature molding, then moldability is improved, but dimensional stability is not sufficiently ensured
Solution Approach 1:
The patent applies parameter changes by optimizing the diol component composition to achieve a balance between moldability and dimensional stability. The specific compositional parameters (ethylene glycol: 85-95 mol%, cyclohexane dimethanol: 5-15 mol%) enable the film to have appropriate softness for molding while maintaining sufficient dimensional stability through controlled crystallization behavior and molecular structure.
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 film exhibits improved moldability, dimensional stability, and heat resistance, enabling successful molding across a wide temperature range without quality decline, suitable for various applications including building materials and automotive components.
Implementation Method 1
crystal melting peak temperature (TmA) of the polyester A layer is greater than or equal to 246°C and less than or equal to 254°C, and crystal melting peak temperature (TmB) of the polyester B layer is greater than or equal to 235°C and less than 246°C
Data Source
AI summary
The present invention addresses the problem of providing a biaxially oriented polyester film for molding which has good moldability, high dimensional stability, high heat resistance and excellent appearance quality after molding and can be molded and appropriately used in various molded members. The biaxially oriented polyester film for molding, wherein: the storage modulus in the film lengthwise direction and the storage modulus in the widthwise direction at 100°C are each 10-1000 MPa inclusive; the storage modulus in the film lengthwise direction and the storage modulus in the widthwise direction at 180°C are each 41-400 MPa inclusive; and the stress at 100% elongation (F100 value) in the film lengthwise direction and the F100 value in the widthwise direction at 150°C are each 5-60 MPa inclusive.