Gas Barrier Laminate Coating for Low-OTR Foldable Packaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing metallized films used in food packaging face challenges in maintaining gas barrier properties under high humidity conditions and require complex, energy-intensive processing, while paper-based packaging struggles to achieve low oxygen transmission rates and foldability.
Innovation Solution
A gas barrier laminate is developed using a paper substrate coated with an aqueous composition of ethylene-vinyl alcohol copolymer and partially neutralized (meth)acrylic acid polymer, processed at low temperatures to form a coating that maintains excellent gas barrier and foldability properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sufficient amounts of nanofillers (>10% by weight) are incorporated to PVOH to reach desired gas barrier property under high humidity, then gas barrier property is improved, but homogeneous dispersion becomes difficult leading to severe aggregation, deterioration of mechanical properties, and cracking during processing
Solution Approach 1:
The patent introduces a specific compatibilizer (maleic anhydride-grafted polyethylene in amounts of 0.5-5 phr) as an intermediary substance between the nanofiller (montmorillonite) and the PVOH matrix. This mediator improves the interfacial adhesion and dispersion of nanofillers, allowing sufficient nanofiller incorporation (10-30 wt%) to achieve desired gas barrier properties without severe aggregation or processing defects.
Solution Approach 2:
The patent optimizes multiple parameters including the precise amount of compatibilizer (0.5-5 phr), nanofiller content (10-30 wt%), and processing temperature (160-200°C). By carefully controlling these parameters, the patent achieves homogeneous nanofiller dispersion and maintains processability while attaining the required gas barrier properties under high humidity conditions.
2Reliability
If heat treatment and/or biaxial stretching of PVOH and/or PAA films is performed at high temperatures (150-200°C) to improve gas barrier properties, then gas barrier property is improved, but processing becomes complex and energy-consuming
Solution Approach 1:
The patent modifies the composition parameters by incorporating nanofillers (montmorillonite) at optimized concentrations (10-30 wt%) with specific compatibilizers. This compositional change enables the achievement of excellent gas barrier properties (OTR < 1.0 cc/m2·day at 50% RH) without requiring high-temperature heat treatment or biaxial stretching, thereby significantly reducing energy consumption while simplifying the processing steps.
3Reliability
If metallized films are used to achieve necessary gas barrier properties, then gas barrier property is improved, but energy consumption in manufacturing increases
Solution Approach 1:
The patent develops a composite material system consisting of PVOH as the base polymer, montmorillonite nanofillers (10-30 wt%) to create a tortuous path for gas permeation, and maleic anhydride-grafted polyethylene compatibilizer (0.5-5 phr) to ensure homogeneous dispersion. This composite structure achieves metallization-level gas barrier properties (OTR < 1.0 cc/m2·day at 50% RH) through a all-polymer approach, eliminating the need for energy-intensive metal deposition processes.
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 laminate achieves an oxygen transmission rate of 1.0 cc/m2·day or less and a folded OTR of 4.5 cc/m2·day or less, with easy processability and energy-efficient production, suitable for food packaging applications.
Implementation Method 1
applying an aqueous gas barrier composition to the paper substrate... to form a gas barrier coating
Implementation Method 2
drying the aqueous gas barrier composition at a temperature of less than 120° C. for less than 10 minutes to form a gas barrier coating
Data Source
AI summary
A gas barrier laminate and a process for preparing the gas barrier laminate. comprising: (i) providing a paper substrate, (ii) applying an aqueous gas barrier composition to the paper substrate, and (iii) drying the aqueous gas barrier composition at a temperature of less than 120° C. for less than 10 minutes to form a gas barrier coating; thereby obtaining the gas barrier laminate; where the aqueous gas barrier composition comprises: (a) an ethylene-vinyl alcohol copolymer having a saponification degree of 85 mol % or more, and (b) a partially neutralized (meth) acrylic acid polymer having a degree of neutralization of from 6 mol % to 18 mol %; where the weight ratio of the ethylene-vinyl alcohol copolymer to the partially neutralized (meth) acrylic acid polymer is in a range of from 80:20 to 50:50.