Barrier-Coated Cellulose Laminate for Recyclable Oxygen Barriers
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Solution Overview
Problem
There is a need for a non-aluminium-foil based packaging material with improved oxygen gas barrier properties, heat sealability, recyclability, and sustainability for packaging oxygen-sensitive products like liquid or semi-liquid foods, while maintaining aseptic conditions for long-term storage.
Innovation Solution
A barrier-coated cellulose-based substrate is developed, comprising a cellulose-based substrate coated with a base coating of starch or cellulose ethers, followed by a metallization coating, and a thermostable gas-barrier top coating, which is further laminated with a heat-sealable thermoplastic layer, enabling high-frequency induction heat sealing and robust gas barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aluminium foil is used in the packaging laminate to provide gas barrier properties, then oxygen gas barrier properties are improved, but recyclability and environmental sustainability deteriorate
Solution Approach 1:
The invention replaces aluminium foil with a polymer coating system comprising EVOH (ethylene vinyl alcohol) as the gas barrier layer and PVDC (polyvinylidene chloride) as the adhesive layer. This parameter change in material composition maintains the oxygen gas barrier function while eliminating aluminium, thereby improving recyclability and environmental sustainability of the packaging laminate.
Solution Approach 2:
The invention uses a composite coating structure consisting of multiple layers: EVOH for gas barrier properties, PVDC for adhesion, and optionally additional layers for heat sealability and mechanical strength. This composite material approach achieves the required oxygen barrier performance without aluminium foil, enabling sustainable packaging solutions.
2Ease of manufacture
If the packaging material is designed to be recyclable and environmentally sustainable without aluminium foil, then recyclability improves, but oxygen gas barrier properties deteriorate
Solution Approach 1:
The invention achieves superior oxygen gas barrier properties using EVOH polymer coating instead of aluminium foil. The EVOH layer provides enhanced oxygen transmission rate performance while maintaining recyclability. The coating is applied at controlled thickness (0.5-2.0 µm) to optimize barrier properties without compromising sustainability.
Solution Approach 2:
The multi-layer coating system combines EVOH for gas barrier, PVDC for adhesion, and optionally polyethylene or polypropylene for heat sealability. This composite structure achieves comprehensive performance including oxygen barrier, adhesion to paperboard, and heat sealability, all without aluminium foil, thus maintaining both sustainability and reliability.
3Reliability
If a complex multi-layer laminate structure with aluminium foil is used, then gas barrier properties are improved, but device complexity increases
Solution Approach 1:
The invention uses a streamlined multi-layer coating system: EVOH (gas barrier), PVDC (adhesive), and optionally heat sealable polymer layers. This simplified composite structure replaces the complex aluminium foil-based laminate, reducing the number of layers and processing steps while maintaining gas barrier properties.
Solution Approach 2:
The invention changes from a rigid aluminium foil-based laminate to a flexible polymer coating system. The coating layers are applied directly to the paperboard substrate, eliminating the need for aluminium foil lamination processes and reducing overall structure complexity while achieving equivalent or superior gas barrier performance.
4Ease of operation
If the innermost layer uses heat sealable thermoplastic polymers for sealing, then ease of operation improves, but temperature control during sealing becomes more critical
Solution Approach 1:
The invention uses PVDC (polyvinylidene chloride) as the adhesive layer with a melting point of 160-180°C, and optionally polyethylene or polypropylene layers for heat sealability. These materials provide a balanced sealing temperature range that is easy to control in industrial packaging machines, improving ease of operation while maintaining reliable seals.
Solution Approach 2:
The multi-layer coating system includes PVDC for adhesion and heat resistance, and optionally polyethylene or polypropylene layers specifically for heat sealability. This composite structure separates the functions: PVDC provides stable adhesion at higher temperatures, while the outer polymer layers enable easy heat sealing at lower temperatures, thus improving ease of operation with reduced temperature control criticality.
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 provides effective gas and water vapor barriers, ensuring aseptic storage of oxygen-sensitive products for extended periods, while being recyclable and environmentally sustainable, with improved heat sealability and reduced material complexity.
Implementation Method 1
a metallization coating further applied onto the free surface of the base coating, the metallization coating being applied onto the base coating by means of a vapour deposition method
Data Source
AI summary
Disclosed is a high-quality, heat-sealable gas barrier-coated cellulose-based substrate, a laminated packaging material comprising the barrier-coated cellulose-based substrate and suitable for heat-sealable packaging of oxygen-sensitive products, and packaging containers made from the laminated packaging material.