Formable PET Films with Metaphase Transition for Thermoforming
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current biaxially-oriented polyethylene terephthalate (PET) films have limited moldability, leading to splitting or breaking during thermoforming, which restricts their utility in producing thermoformed trays and cavities, necessitating the use of alternative materials.
Innovation Solution
Development of formable PET films with a metaphase transition of 180° C to 200° C, induced through specific stretching and crystallization processes, enhancing tensile strength, drawability, and thermoformability, allowing for greater elongation and molded volume without the need for copolymers or blends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional biaxially-oriented PET films are used, then material strength and stability are maintained, but moldability deteriorates causing splitting or breaking during thermoforming
Solution Approach 1:
The patent applies parameter changes by modifying the thermal and mechanical parameters during film production. Specifically, the film is stretched at controlled temperatures and rates to create a metaphase structure, then annealed at specific temperatures (150-200°C) to stabilize this phase. These parameter changes enable the PET film to achieve both high tensile strength and improved moldability, resolving the contradiction between strength and ease of manufacture.
Solution Approach 2:
The patent utilizes phase transitions by inducing a metaphase in the PET film through controlled stretching and thermal treatment. This metaphase transition occurs at specific temperature ranges (150-200°C annealing) and creates a unique molecular structure that provides both the strength of conventional PET and the moldability needed for thermoforming. The phase transition is the core mechanism that resolves the technical contradiction.
2Ease of manufacture
If stretching and crystallization processes are applied to enhance formability, then thermoformability improves, but process complexity increases
Solution Approach 1:
The patent applies preliminary action by performing stretching and metaphase induction during the film production stage, before the film reaches the end user. The stretching process creates the metaphase structure, and subsequent annealing stabilizes it. This preliminary preparation means that when the film is later used for thermoforming, it already possesses the desired formability without requiring complex real-time processing equipment or procedures at the manufacturing site.
3Ease of manufacture
If copolymers or blends are used to improve moldability, then thermoformability increases, but material purity and simplicity deteriorate
Solution Approach 1:
The patent resolves this contradiction by changing physical parameters (temperature, stretching rate, annealing conditions) rather than chemical composition. The metaphase is induced through controlled mechanical and thermal parameters applied to pure PET, without introducing copolymers or blends. This maintains material purity and simplicity while achieving the desired moldability, directly addressing the technical contradiction.
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 formable PET films exhibit increased tensile strength, elongation, and thermoformability, enabling them to form cavities with minimal spring-back force and improved properties compared to conventional PET films, suitable for various packaging applications.
Implementation Method 1
a metaphase with a metaphase transition of about 180° C. to 200° C. as measured by differential scanning calorimetry (DSC) upon a first heating
Implementation Method 2
induced through specific stretching and crystallization processes
Implementation Method 3
Thermal heating, however, is the most preferred methodology due to simplicity and cost considerations
Implementation Method 4
The negative pressure on the bottom side of a flat web over a mold orifice provides a driving force to distort the web stock into the final desired shape
Data Source
AI summary
Formable films are provided that include one or more biaxially-oriented polyethylene terephthalate layers. The formable films include a metaphase with a metaphase transition of about 180° C. to 200° C. as measured by differential scanning calorimetry (DSC). The formable films further include a molded volume of greater than 200%. Laminate structures including the formable films and processes for producing and using the formable films and laminate structures are also provided.