Multilayer Heat-Shrinkable Film Microlayer Segmentation
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Solution Overview
Problem
There is a need to reduce the amount of polymer used in heat-shrinkable films while maintaining their physical properties to conserve resources and reduce material waste, as conventional methods require significant amounts of petroleum and natural gas-derived polymers.
Innovation Solution
A multilayer heat-shrinkable film is developed with a bulk layer and a microlayer section comprising a plurality of microlayers, where the microlayers have a thickness ratio to the bulk layer ranging from 1:2 to 1:40, allowing for a thinner film with improved Elmendorf Tear resistance and reduced polymer usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional single-layer or multi-layer extrusion methods are used, then the film structure is simple and manufacturing is easier, but the polymer usage is excessive and physical properties are insufficient
Solution Approach 1:
The film is divided into multiple thin layers (10-50 microlayers) with different polymer compositions, where each microlayer contributes specific functional properties. This segmentation allows optimization of polymer usage by assigning materials strategically to different layers rather than using excessive amounts of a single material throughout the entire film structure.
Solution Approach 2:
The invention employs composite material structures by combining multiple polymer types in a multilayer configuration. Each microlayer can contain different polymers or polymer blends, creating a composite structure that achieves superior physical properties (tear resistance, heat shrinkability, barrier properties) while reducing overall polymer consumption compared to conventional single-layer films.
2Quantity of substance
If the film thickness is reduced to save material, then polymer usage decreases and environmental impact is reduced, but the Elmendorf Tear resistance and physical properties deteriorate
Solution Approach 1:
Instead of using a single thick layer, the film is segmented into 10-50 thin microlayers. This segmentation allows the total film thickness to be reduced while maintaining structural integrity through the distributed architecture of multiple layers, each contributing to the overall tear resistance.
Solution Approach 2:
Different microlayers are designed with different local qualities - some layers may contain polymers optimized for tear resistance, others for heat shrinkability, and others for barrier properties. This local optimization ensures that each region of the film performs its specific function effectively, maintaining high Elmendorf Tear resistance despite reduced overall thickness.
3Strength
If a multilayer structure with many microlayers is created, then physical properties and polymer efficiency are improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The multilayer film structure serves multiple functions simultaneously - different microlayers provide tear resistance, heat shrinkability, barrier properties, and sealing characteristics. This multi-functionality is achieved within a single integrated film structure that can be manufactured in one continuous extrusion process, avoiding the need for separate manufacturing steps for each function.
Solution Approach 2:
The invention controls the complexity by defining specific parameter ranges: 10-50 microlayers with thickness ratios between 1:2 to 1:40 relative to bulk layers. These parameter specifications provide a standardized framework that guides the manufacturing process, ensuring consistent physical properties while managing production complexity through quantifiable design criteria.
4Quantity of substance
If the thickness ratio of microlayers to bulk layers is optimized, then polymer usage is reduced and efficiency is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The invention establishes specific parameter ranges for manufacturing: microlayer thickness ratios of 1:2 to 1:40 relative to bulk layers, and total film thickness reductions of 50% or more. These parameter specifications provide clear manufacturing targets that balance material efficiency with achievable production precision, enabling optimization without requiring extreme manufacturing capabilities.
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 multilayer film achieves a 50% reduction in polymer usage while maintaining or exceeding the properties of thicker conventional films, including high Elmendorf Tear resistance and free shrink, enabling efficient packaging with reduced environmental impact.
Implementation Method 1
extrusion (single layer films) or coextrusion (multilayer films) of thermoplastic polymeric materials which have been heated to their flow or melting point
Implementation Method 2
After a post-extrusion quench to cool, e.g., by water immersion
Implementation Method 3
reheated to a temperature within its orientation temperature range and stretched to orient or align the crystallites and/or molecules of the material
Implementation Method 4
the orientation temperature range for a given material or materials will vary with the different resinous polymers and/or blends thereof which comprise the material. However, the orientation temperature range for a given thermoplastic material may generally be stated to be below the crystalline melting point of the material but above the second order transition temperature
Implementation Method 5
quickly quenched while substantially retaining its stretched dimensions to rapidly cool the film and thus set or lock-in the oriented (aligned) molecular configuration
Implementation Method 6
after being extruded but prior to being stretch-oriented, the film is irradiated, normally with electron beams, to induce cross-linking between the polymer chains that make up the film
Implementation Method 7
An oriented (i.e., heat-shrinkable) material will tend to return to its original unstretched (unextended) dimensions when heated to an appropriate elevated temperature
Implementation Method 8
The terms 'orientation' or 'oriented' are used herein to generally describe the process step and resultant product characteristics obtained by stretching and immediately cooling a thermoplastic polymeric material which has been heated to a temperature within its orientation temperature range so as to revise the molecular configuration of the material
Data Source
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AI summary
A multilayer, heat-shrinkable film (94) generally includes at least one bulk layer (90, 96,98,100) and a microlayer section (60) comprising a plurality of microlayers. The ratio of the thickness of any of the microlayers to the thickness of the bulk layer ranges from about 1 :2 to about 1 :40.