Biaxially Oriented Multilayer Films with Intralayer Voids
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Solution Overview
Problem
Current technologies face challenges in producing biaxially oriented multilayer films with lower densities while maintaining transparency, as existing solutions often require sacrificing barrier properties and thermal resistance.
Innovation Solution
The development of biaxially oriented multilayer films with intralayer voids, where the first composition includes a first thermoplastic and a first polymer immiscible with the thermoplastic, and the second composition includes a second thermoplastic, allowing for controlled density reduction without compromising transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional thermoplastic materials are used to produce biaxially oriented films, then barrier properties and thermal resistance are maintained, but density cannot be reduced without sacrificing transparency
Solution Approach 1:
The patent introduces intralayer voids within the thermoplastic material to create a porous structure. These voids reduce the bulk density of the film while their controlled size and distribution prevent significant light scattering, thereby maintaining transparency. The voids are formed by incorporating a void-forming agent that creates cavities during the extrusion and orientation process.
Solution Approach 2:
The patent creates a composite material system consisting of the thermoplastic matrix combined with intralayer voids. This composite structure allows the material to exhibit both reduced density (due to the voids) and maintained transparency (due to the controlled morphology of the voids within the transparent thermoplastic matrix).
2Quantity of substance
If material quantity is reduced to decrease density, then cost and environmental impact are improved, but barrier properties deteriorate
Solution Approach 1:
The intralayer voids create a porous structure that reduces material consumption and bulk density while the voids are designed with specific size and distribution characteristics that do not significantly compromise barrier properties. The high aspect ratio of the voids (width-to-height ratio from 10:1 to 100:1) allows light to pass through without significant scattering, maintaining transparency.
Solution Approach 2:
The patent changes the physical parameters of the material structure by introducing voids with specific dimensional characteristics (width-to-height ratio from 10:1 to 100:1). This parameter change allows the material to achieve reduced density and improved transparency while the multilayer configuration and void morphology are optimized to maintain adequate barrier properties.
3Productivity
If high stretching ratios are applied to reduce density, then material yield is improved, but crystallinity increases resulting in decreased transparency
Solution Approach 1:
Instead of relying solely on high stretching ratios to reduce density, the patent uses a controlled porous structure with intralayer voids. This approach allows density reduction without the need for extreme stretching that would otherwise increase crystallinity and reduce transparency. The voids are formed during extrusion and maintain their morphology through controlled orientation processing.
Solution Approach 2:
The patent changes the processing parameters by forming voids during extrusion rather than relying on post-extrusion stretching to create density reduction. The width-to-height ratio of voids is controlled to be from 10:1 to 100:1, and the stacking sequence is optimized to achieve the desired balance between density, transparency, and barrier properties without requiring excessive stretching that would increase crystallinity.
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
This approach achieves multilayer films with reduced density and low bulk haze, enhancing transparency and maintaining desirable properties such as barrier properties and thermal resistance.
Implementation Method 1
Cavitation or admixing with miscible materials of lower bulk density may be used to reduce the density of thermoplastic filmic materials. In the case of highly oriented films, cavitation can reduce density of film.
Implementation Method 2
Embodiments of the present disclosure generally relate to biaxially oriented multilayer films and, more specifically, to biaxially orientated multilayer films that exhibit lower densities and improved transparency.
Data Source
AI summary
The biaxially oriented multilayered films include a stack (A-B)n of n layer units A-B, where n is greater than or equal to 32 each layer unit A-B having individual layers comprising a first layer A and a second layer B overlying the first layer A. The biaxially oriented multilayer films include intralayer voids within a portion of the individual layers in the stack. The intralayer voids have width-to-height aspect ratios from 20:1 to 500:1. The first layers of the layer units have a first composition, and the second layers of the layer units have a second composition. The first composition includes a first thermoplastic and a first polymer immiscible with the first thermoplastic. The second composition includes a second thermoplastic that may be the same as or different from that of the first thermoplastic.