Multimodal Polyethylene Extrusion Coating Composition
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Solution Overview
Problem
Low density polyethylene (LDPE) extrusion compositions lack sufficient abuse resistance and toughness for many applications, and existing methods to improve their properties result in unsuitable heat seal characteristics or require blending with linear polyethylene resins, which compromises desired physical properties.
Innovation Solution
Development of multimodal polyethylene extrusion compositions comprising a high molecular weight component with substantial long chain branching and a low molecular weight component, blended with LDPE, to achieve high line speeds, reduced neck-in, and improved extrusion processability, with the multimodal polyethylene component making up 80-98% of the composition and LDPE making up 2-20%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If LDPE is used for extrusion coating, then excellent extrusion processability and high extrusion drawdown rates are achieved, but sufficient abuse resistance and toughness are lacking
Solution Approach 1:
The patent creates a composite material system by blending LDPE with linear polyethylene resins (HDPE, LLDPE, or ULDPE) in specific ratios (at least 30 wt% linear resin). This composite approach combines the processability benefits of LDPE with the strength and toughness of linear polyethylene, resolving the contradiction between ease of operation and mechanical strength.
2Strength
If linear polyethylene resins are used, then improved abuse resistance, toughness, and barrier resistance are achieved, but extrusion processability deteriorates with high neck-in, draw resonance, and high motor load
Solution Approach 1:
The patent changes the compositional parameters by formulating specific blends of linear polyethylene resins with LDPE, where the linear resin content is controlled at at least 30 wt%. This parameter adjustment optimizes the balance between mechanical properties and extrusion processability, reducing neck-in and draw resonance while maintaining strength and toughness.
3Reliability
If LDPE is blended with linear polyethylene to improve coating performance, then coating performance is improved, but desired physical properties are compromised
Solution Approach 1:
The patent optimizes the blending ratio parameter by specifying that linear polyethylene resin constitutes at least 30 wt% of the composition. This specific parameter range achieves the dual goal of improving coating performance through LDPE while maintaining adequate physical properties through sufficient linear polyethylene content.
Data Source
AI summary
Multimodal polyethylene compositions are provided. Extrusion compositions including the multimodal polyethylene are provided. The extrusion composition further include a high pressure low density polyethylene and optionally other additives and/or polyethylenes. Extruded articles made from the polyethylene extrusion compositions are also provided.