Multi-layered Thermoplastic Films with Visually Distinct Stretched Regions
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Solution Overview
Problem
Thermoplastic films face challenges in balancing strength, breathability, and opacity, particularly in applications like trash bags and food storage bags, where consumers prefer non-porous and opaque materials to ensure integrity and privacy, while existing stretching methods often compromise on these properties or require costly additives like TiO2.
Innovation Solution
The development of multi-layered thermoplastic films with visually distinct stretched regions created by incremental stretching, using a voiding agent in some layers to enhance opacity and strength without making the film porous, achieved through techniques like MD ring rolling, TD ring rolling, and the formation of strainable networks, which allows for reduced pigment use and maintains film integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If thermoplastic film is stretched to reduce thickness and material usage, then material cost is reduced, but the film becomes more transparent and consumers perceive it as weaker
Solution Approach 1:
The patent applies stress whitening through incremental stretching to create opaque white regions in the film. This optical change makes the thin film appear thicker and stronger to consumers, resolving the perception issue while maintaining material reduction benefits
Solution Approach 2:
The patent changes the physical state of the film by applying incremental stretching that creates micro-voids and crystalline structures. This transforms the film from transparent to opaque through physical parameter changes rather than chemical additives
2Illumination intensity
If pigments like TiO2 are added to increase opacity in stretched films, then opacity is improved, but film strength properties are negatively impacted and costs increase
Solution Approach 1:
The patent replaces chemical pigments with a mechanical process (incremental stretching) to achieve opacity. The mechanical action creates physical structures that scatter light, eliminating the need for strength-degrading chemical additives
Solution Approach 2:
The patent converts the potential harm of over-stretching (which normally creates pores and weakens the film) into a benefit by controlling the stretching to create opaque regions without compromising overall film integrity or strength
3Productivity
If voiding agent is used during stretching to create breathable film, then breathability is improved, but opacity is reduced and film strength is compromised
Solution Approach 1:
The patent applies voiding agents locally in specific layers rather than throughout the entire film structure. This creates breathable regions where needed while maintaining opaque and strong regions in other layers, allowing simultaneous achievement of breathability and opacity
Solution Approach 2:
The patent divides the film into multiple layers with different functions: some layers contain voiding agents for breathability while other layers provide opacity and strength. This segmentation allows each layer to optimize its specific function without compromising overall film performance
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 creates films that appear more opaque and stronger, conveying improved properties to consumers while reducing material usage and pigment costs, ensuring non-porous or breathable properties as needed for specific applications without compromising on strength or transparency.
Implementation Method 1
Upon stretching, the voiding agent can cause the stretched regions of the film to become more opaque than un-stretched regions of the film
Implementation Method 2
incremental stretching...creation of strainable networks
Data Source
AI summary
Multi-layered thermoplastic films include intermittent stretched regions that are visually distinct from un-stretched regions. The stretched regions can be white, opaque, and non porous. The multi-layered thermoplastic films with visually-distinct stretched regions can be formed into bags for use as trash can liners or food storage. Additionally, methods of stretching thermoplastic films to create visually distinct stretched regions include incrementally stretching a plurality of film layers, at least one of which includes a thermoplastic material and a voiding agent.