Cross-linked EVOH Coatings for Humidity-Resistant Barrier Films
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Solution Overview
Problem
Conventional EVOH copolymer coatings suffer a decline in water vapor and oxygen transmission resistance at high humidity levels, and their stability is compromised over time, affecting the barrier properties of polymeric films used in packaging applications.
Innovation Solution
The development of cross-linked EVOH copolymer coatings, which can be applied as single or multi-layered films, either metallized or non-metallized, providing enhanced water vapor and oxygen barrier properties, improved optics, and stability, with the cross-linking process occurring after application to ensure adhesion and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional EVOH copolymer coatings are applied to polymeric films, then water vapor and oxygen barrier properties are provided, but the barrier properties decline at high humidity levels and over time
Solution Approach 1:
The patent applies composite materials by combining EVOH copolymer with cross-linking agents (such as melamine, urea, or silane-based cross-linkers) to create a cross-linked composite coating system. This composite structure maintains the excellent barrier properties of EVOH while adding the stability and humidity resistance provided by the cross-linked network, thereby resolving the contradiction between barrier performance and stability at high humidity levels
Solution Approach 2:
The patent changes the chemical parameter of the coating by introducing cross-linking reactions that transform the linear EVOH copolymer chains into a three-dimensional cross-linked network. This parameter change (from linear to cross-linked structure) fundamentally improves the coating's resistance to humidity and temporal degradation while preserving its barrier functionality
2Stability of the object's composition
If cross-linked EVOH copolymer coatings are applied, then stability and adhesion are improved, but the coating process becomes more complex
Solution Approach 1:
The patent applies preliminary action by pre-formulating the coating composition with both the EVOH copolymer and the cross-linking agent incorporated together in a stable aqueous solution. This preliminary preparation allows the coating to be applied in a single step, with the cross-linking reaction occurring subsequently during drying or curing, thereby simplifying the overall process despite the chemical complexity involved
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 cross-linked EVOH copolymer coatings exhibit superior resistance to water vapor and oxygen transmission across a range of humidity levels, maintaining barrier properties even after exposure to high humidity and demonstrating increased stability and adhesion, making them suitable for various packaging applications, including food and snack products.
Implementation Method 1
The coated films exhibit beneficial water vapor and oxygen transmission rates
Implementation Method 2
coating solutions suitable for use on polymeric films
Data Source
AI summary
Polymeric film structures incorporating at least one coating comprising a cross-linked EVOH copolymer and coating solutions suitable for use on polymeric films comprising at least one EVOH copolymer and at least one cross-linker are provided. The coated films may be single or multi-layered film structures. The films may also be metallized. The coated films exhibit beneficial water vapor and oxygen transmission rates. The coated films may also exhibit the beneficial barrier characteristics under conditions of high humidity. The coated films are suitable for packaging applications. The coating solutions exhibit beneficial stability characteristics over extended time periods.