High-Temperature Liner with Propylene Elastomer Tie Layer
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Solution Overview
Problem
Traditional polyethylene and polypropylene liners fail to balance stiffness, toughness, and seal strength when packaging high-temperature materials above 120°C, as polyethylene melts below 135°C and polypropylene lacks sufficient load-bearing capacity due to poor seal strength and dart impact resistance.
Innovation Solution
A liner comprising a first layer of polyethylene, a tie layer of propylene-based elastomer, and a second layer of polypropylene with a melting point greater than 140°C, where the tie layer is disposed between the first and second layers, enhancing dart impact resistance and seal strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If polyethylene plies are used to package high temperature materials, then the liner provides good seal strength and toughness, but the liner fails at temperatures above 135°C due to melting
Solution Approach 1:
The patent uses a composite structure with multiple layers: an inner polyethylene layer (providing seal strength and toughness), a middle tie layer containing propylene-based elastomer (providing heat resistance up to 140°C), and an outer polypropylene layer (providing additional thermal stability). This composite structure allows the liner to maintain both seal strength and high-temperature resistance simultaneously.
2Temperature
If polypropylene plies are used to increase melting point, then the liner can hold higher temperature materials, but the liner exhibits poor seal strength and dart impact resistance
Solution Approach 1:
The patent applies local quality by assigning different functions to different layers: the inner polyethylene layer specifically provides seal strength and dart impact resistance where needed for packaging integrity, while the outer polypropylene layer provides thermal stability for high-temperature resistance. Each layer performs its specialized function optimally.
3Strength
If a single-layer structure is used, then the liner is simple to manufacture, but it cannot provide both high dart impact and balanced stiffness, toughness, and seal strength
Solution Approach 1:
The patent segments the liner into multiple functional layers: polyethylene layers for seal strength and toughness, propylene-based elastomer tie layers for heat resistance and bonding, and polypropylene layers for thermal stability. Each segment performs a specific function, and the combination achieves high dart impact (greater than 5 g/μm) while maintaining balanced mechanical properties.
Data Source
AI summary
Provided are liners suitable for use in a bulk container. The liners can hold high temperature materials (e.g., materials reaching temperatures greater than 120° C.) and can comprise at least one ply including polyethylene. The liners can exhibit high dart impact and can provide a balance of stiffness, toughness, and seal strength. The at least one ply of the liner according to embodiments disclosed herein comprises a first layer, a tie layer, and a second layer, wherein the tie layer is disposed between the first layer and the second layer. In further embodiments, the at least one ply of the liner can include a second tie layer and a third layer, wherein the second tie layer is disposed between the first layer and the third layer.