Polyethylene Structure with Layered Polyamide for Fuel Barrier
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Solution Overview
Problem
Conventional polyethylene-based containers face challenges in achieving stringent barrier properties and strength, particularly in storing hydrocarbons, due to issues with permeation and insufficient adhesion in pinch-off portions, which are not adequately addressed by existing methods such as fluorination, multilayer structures, or the use of nylon 6,66 and N-MXD6 resins.
Innovation Solution
A polyethylene-based structure comprising 60-90% high-density polyethylene, 5-35% acid-modified polyethylene, and 5-35% m-xylylene group-containing polyamide, where the m-xylylene group-containing polyamide is dispersed in a layer form to form a continuous phase, with specific density and melt flow rate ranges to enhance barrier properties and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluorination treatment or sulfone treatment is applied to enhance barrier property, then gas-barrier property is improved, but harmful gases are generated and quality inspection becomes difficult
Solution Approach 1:
The invention changes the chemical composition parameters by incorporating specific barrier resins (EVOH with 2-15 wt%, polyamide with 3-20 wt%, and/or N-MXD6 with 1-15 wt%) into the HDPE composition, achieving enhanced gas-barrier properties without requiring fluorination or sulfone treatments that generate harmful gases
Solution Approach 2:
The invention creates a composite material system by blending HDPE with barrier resins (EVOH, polyamide, N-MXD6) and adhesive resins, forming a multicomposition material that provides both mechanical strength and enhanced gas-barrier properties without harmful chemical treatments
2Reliability
If multilayer wall structure with EVOH layer is formed to enhance barrier property, then barrier property is improved and controlled, but existing HDPE production facilities cannot be used and special multilayer blow-molding equipment is required
Solution Approach 1:
The invention merges the functions of multiple layers (barrier function and structural function) into a single-layer structure by blending HDPE with barrier resins and adhesive resins, allowing production using existing single-layer HDPE blow-molding facilities while achieving enhanced barrier properties
Solution Approach 2:
The invention creates a universal composition that can be processed on existing HDPE production lines while providing multiple functions (structural integrity, barrier protection, adhesion) that were previously requiring separate layers and specialized equipment
3Reliability
If nylon 6,66 or N-MXD6 is used in blended resin single-layer container to enhance fuel barrier property, then fuel barrier property is improved, but adhesion at pinch-off portion becomes insufficient
Solution Approach 1:
The invention introduces adhesive resins (polyethylene-graft-maleic anhydride with 5-20 wt%, polyvinylidene fluoride with 3-15 wt%, or carboxymethyl cellulose with 1-10 wt%) as intermediary materials that enhance adhesion at the pinch-off portion while maintaining the fuel barrier properties provided by barrier resins
Solution Approach 2:
The invention creates a composite material system combining HDPE, barrier resins (nylon 6,66, N-MXD6, EVOH), and adhesive resins in specific proportions, achieving both improved fuel barrier property and sufficient adhesion strength at pinch-off portions
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 proposed structure exhibits excellent barrier properties against fuels and gases, along with practical strength, effectively preventing permeation and maintaining structural integrity, particularly in fuel containers and pipes.
Implementation Method 1
the HDPE has such a problem that contents stored in a container made of the HDPE are likely to be permeated through a wall of the HDPE container
Implementation Method 2
5-35% by mass of an acid-modified polyethylene (B)
Data Source
AI summary
The present invention provides a polyethylene-based structure including from 60 to 90% by mass of a polyethylene (A), from 5 to 35% by mass of an acid-modified polyethylene (B) and from 5 to 35% by mass of a m-xylylene group-containing polyamide (C), in which the m-xylylene group-containing polyamide (C) is dispersed in a layer form in the polyethylene (A) to partially form a continuous phase thereof, and has a relative viscosity of from 2.5 to 4.5.