Polydimethylsiloxane Multilayer Films for Flex Crack Resistance
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Solution Overview
Problem
Existing multilayer films used in large format liquid packaging bags face issues such as pinhole formation during transportation, leading to material loss and increased costs due to complex film structures and non-recyclable materials, while requiring high flex crack resistance and surface heat resistance.
Innovation Solution
A multilayer film composed of at least three layers, including a first and second skin layer and a core layer, all made predominantly of polyolefin with 0.05-5.0% polydimethylsiloxane, providing high flex crack resistance and recyclability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex multilayer film structures with multiple materials are used to achieve high flex crack resistance, then Gelbo flex crack performance is improved, but raw material costs increase and manufacturing complexity increases
Solution Approach 1:
The patent uses a homogeneous single-polymer (polyethylene) material throughout all layers of the multilayer film structure, eliminating the need for different materials while achieving the required flex crack resistance through molecular weight distribution and layer architecture optimization
Solution Approach 2:
The film is divided into multiple layers with different molecular weight polyethylene compositions, where each layer serves a specific function: the first and second skin layers provide surface properties and flex crack resistance, while the core layer provides bulk mechanical properties, achieving high reliability without material complexity
2Reliability
If multilayer structures incorporating polypropylene, polyamide, and polyethylene terephthalate are used to achieve desired performance properties, then flex crack performance is improved, but recyclability deteriorates
Solution Approach 1:
The entire multilayer film structure is made from a single polymer type (polyethylene), ensuring that all layers are chemically compatible and can be recycled together as a single material stream, eliminating the recyclability problems associated with mixed-material laminates
Solution Approach 2:
The patent creates a composite structure using different molecular weight grades of the same polymer (polyethylene), achieving the performance benefits of multilayer structures while maintaining material homogeneity for recyclability
3Reliability
If multiple plys and dunnage systems are used to reduce pinhole risk during transportation, then reliability is improved, but material costs and labor costs increase
Solution Approach 1:
The patent optimizes the molecular weight distribution parameters of the polyethylene material, using a combination of high molecular weight polyethylene for flex crack resistance and lower molecular weight polyethylene for processability, achieving high reliability without additional materials or structures
Data Source
AI summary
Embodiments of the present invention relate to multilayer films, bags, and other articles. In one aspect, a multilayer film comprises at least three layers: (a) a first skin layer, (b) a core layer, and (c) a second skin layer opposite the first skin layer. Among other features, the first skin layer and the core layer, while having different overall compositions, each comprise from 0.05 weight percent to 5.0 weight percent of at least one polydimethylsiloxane, based on the total weight of the respective layer, wherein at least one of the polydimethylsiloxane has a weight average molecular weight, Mw, of from 20,000 g/mol to 700,000 g/mol.