Multilayer Film Structure with ULDPE Core and EVA Intermediate Layers
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Solution Overview
Problem
Current multi-layer films face challenges in reconciling flexibility with industrial-scale manufacturing constraints, particularly in terms of cost, ease of manufacturing, heat-sealing properties, and maintaining optical quality while preventing delamination.
Innovation Solution
A film structure comprising a polyethylene-based core layer with ULDPE and LLDPE outer layers, and intermediate layers made of EVA and ethylene copolymers, optimized for low shrinkage, high elongation, and mechanical resistance, allowing for low-cost production and effective heat-sealing without delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If current film properties are obtained using traditional materials, then flexibility and shrinkage properties are improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the material parameters by specifying exact polyethylene types (ULDPE for core layer, LLDPE for outer layers) with defined density ranges and molecular weight characteristics. This parameter optimization allows achieving the desired flexibility and shrinkage properties while using cost-effective materials, resolving the contradiction between performance and manufacturing cost.
Solution Approach 2:
The patent employs a composite multilayer structure combining different polyethylene materials (ULDPE core layer, LLDPE outer layers) with specific intermediate layers. This composite approach enables each layer to contribute its specific properties, achieving overall flexibility and shrinkage performance at lower manufacturing cost than single-material solutions.
2Productivity
If film stretching and bi-orientation properties are improved, then manufacturing rate increases, but film delamination during heat-sealing occurs
Solution Approach 1:
The patent applies local quality by creating specific intermediate layers between the core and outer layers with tailored compositions. These intermediate layers are specifically designed to provide adhesion properties that prevent delamination during heat-sealing, while the overall film structure maintains improved stretching and bi-orientation properties for high manufacturing rate.
3Illumination intensity
If optical properties are maintained, then film quality improves, but manufacturing complexity increases
Solution Approach 1:
The patent uses homogeneity by selecting polyethylene materials with consistent density ranges and molecular weight distributions for each layer. This homogeneity in material selection simplifies the manufacturing process while maintaining excellent optical properties, as the consistent material characteristics reduce variability in film properties and eliminate the need for complex processing adjustments.
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 achieves low to medium shrinkage, high elongation, and mechanical resistance, supporting flexible and rigid object packaging with improved manufacturing efficiency and optical properties, while maintaining low raw material costs.
Implementation Method 1
a polyethylene-based core layer with ULDPE and LLDPE outer layers
Implementation Method 2
low to medium shrinkage and cohesion forces, low shrinkage energy, and in particular properties of shrinkage at low temperature
Implementation Method 3
the first and/or second intermediate layer is made of a first composition based on EVA and a copolymer of ethylene and at least one second compound
Implementation Method 4
preventing the heat-sealed film from delaminating
Implementation Method 5
heat-sealed films must have good heat-sealing properties
Implementation Method 6
high mechanical resistance of the sealing
Data Source
AI summary
A film comprising a core layer (5), first and second outer layers (3, 4), first and second intermediate layers (1, 2). The core layer (5) contains at least 50% by weight of a ULDPE. At least one of the outer layers (3, 4) contains at least 50% by weight of a LLDPE. The first and/or second intermediate layer (1, 2) is made of a first composition based on EVA and on a copolymer of ethylene and of at least one compound selected from the group consisting of the linear alkenes of order C greater than ethylene, dienes and cyclic alkenes.