Hydrophobic Modification of EVOH Polymer for Oxygen Barrier
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Solution Overview
Problem
Polymer compositions containing hydroxy alkylene repeating units like EVOH and PVOH face challenges in maintaining oxygen barrier properties while being water-sensitive and requiring complex manufacturing processes and additional layers for moisture barrier, which increases costs and complexity.
Innovation Solution
A composition comprising at least 10% hydroxyl alkylene repeating units and 0.1 to 5% by weight of specific additives, such as N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,3-benzenedicarboxamide, improves oxygen barrier properties without the need for additional moisture-barrier layers, simplifying the manufacturing process and reducing material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EVOH and PVOH are used to improve oxygen barrier properties, then oxygen permeation is reduced, but water sensitivity increases
Solution Approach 1:
A hydrophobic改性 agent acts as an intermediary substance that modifies the hydroxyl groups on the EVOH/PVOH polymer chains, making them less hydrophilic. This intermediary chemical modification allows the polymer to maintain its excellent oxygen barrier properties while reducing its affinity for water, thus resolving the contradiction between oxygen barrier performance and water sensitivity
Solution Approach 2:
The chemical structure parameters of the polymer are changed by introducing hydrophobic groups through reaction with the改性 agent. This parameter change in the polymer's chemical composition transforms it from water-sensitive to moisture-stable, while preserving the oxygen barrier functionality inherent to the hydroxyl alkylene repeating units
2Reliability
If thick layers are used to improve oxygen barrier properties, then oxygen permeation is reduced, but material costs and manufacturing complexity increase
Solution Approach 1:
By changing the chemical composition parameters of the polymer through hydrophobic modification, the material achieves enhanced moisture stability that allows thin single-layer films to perform as effectively as thick multilayer films, thereby simplifying manufacturing processes and reducing equipment complexity
3Reliability
If moisture-barrier layers are added to maintain oxygen barrier properties, then oxygen permeation is controlled, but material costs and manufacturing complexity increase
Solution Approach 1:
The invention extracts and eliminates the need for separate moisture-barrier layers by integrating moisture stability directly into the oxygen barrier polymer through chemical modification. This extraction of the moisture barrier function from a separate layer and its integration into the base polymer reduces material costs and simplifies the overall structure
Solution Approach 2:
The moisture barrier function and oxygen barrier function are merged into a single modified polymer material. The hydrophobic改性 agent combines the oxygen barrier properties of EVOH/PVOH with moisture stability in one integrated material system, eliminating the need for separate moisture barrier layers and reducing overall material costs
4Reliability
If hydroxyl groups are blocked by reaction with aldehyde, then oxygen barrier properties are improved, but processing time and equipment requirements increase
Solution Approach 1:
The polymer modification is designed to occur during the normal extrusion processing itself, rather than requiring a separate pre-reaction step. The hydrophobic改性 agent is fed into the extruder along with the EVOH/PVOH and undergoes reaction in-situ under extrusion conditions, making the process self-service and eliminating additional reaction equipment and time requirements
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 solution significantly reduces oxygen permeability and stabilizes the polymer against moisture, allowing for thinner moisture-barrier layers or their omission, thereby enhancing the efficiency and cost-effectiveness of the polymer composition.
Implementation Method 1
said hydroxyl groups with a hydrophobic modifying agent in an extruder to form a hydrophobic modification
Implementation Method 2
improve the oxygen barrier properties against the permeation of oxygen
Data Source
AI summary
The present invention relates to polymer compositions comprising (a) a polymer containing hydroxyl alkylene repeating units and (b) an additive selected from compounds of the formulae (1) to (6)whereinRa1, Ra2, Ra3 and Ra4 can be the same or different and independently represent a group selected from the moieties having formula (A) or formula (B),whereinRb is selected from hydrogen, C1-6 alkyl, C1-6 alkoxy and —CO—C1-4 alkyl.