Repulpable Packaging Material with Pigmented Barrier Layers
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Solution Overview
Problem
Current packaging materials for liquids and frozen food are difficult to repulp due to issues with separating plastic coatings from paperboard, leading to high grammage and material inefficiency, while maintaining barrier properties against moisture and liquids.
Innovation Solution
A heat-sealable packaging material with a paperboard substrate and symmetric layer arrangement, where pigment-free latex or water-soluble polymer layers are in direct contact with the base board, and outer barrier layers comprise high amounts of pigments, achieving low grammage and high stiffness without the need for polyolefin or metal layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyolefin or metal barrier coatings are applied to provide moisture and liquid barrier properties, then barrier performance is improved, but repulpability deteriorates due to difficulty in separating plastic coating from paperboard
Solution Approach 1:
The invention extracts and removes polyolefin and metal barrier coatings from the packaging material structure, replacing them with water-soluble polymer-based barrier layers that can be easily separated during repulping, thus resolving the contradiction between maintaining barrier properties and enabling repulpability
Solution Approach 2:
The invention changes the chemical composition parameters of the barrier coating from hydrophobic polyolefins and metals to hydrophilic water-soluble polymers, which fundamentally alters the interaction with water during repulping, enabling easy separation while maintaining barrier functionality
2Strength
If grammage of base board and coatings is increased to provide desired stiffness, then mechanical strength is improved, but material consumption increases
Solution Approach 1:
The invention uses composite material structures with water-soluble polymer layers combined with paperboard substrate, where the polymer layers provide enhanced mechanical strength and stiffness at lower weights, reducing overall material consumption while maintaining required structural performance
Solution Approach 2:
The invention employs thin film water-soluble polymer coatings that provide sufficient mechanical reinforcement and stiffness to the paperboard structure without requiring high grammage, thus reducing material consumption while achieving desired mechanical properties
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 packaging material provides excellent barrier properties and stiffness at low grammage, enabling high yield repulpability with reduced reject levels and compliance with food safety regulations.
Implementation Method 1
a first barrier coating layer on the first coating layer, which first barrier coating layer comprises pigments, a second coating layer on the second side, and a second barrier coating layer on the second coating layer, which second barrier coating layer comprises pigments
Implementation Method 2
the first barrier coating layer and the second barrier coating layer comprise pigments in an amount in a range from ≥40 wt % to ≤70 wt %
Data Source
AI summary
The invention relates to a heat-sealable packaging material comprising: a paperboard substrate comprising a first side and a second side, a first coating layer on the first side, a first barrier coating layer on the first coating layer, which first barrier coating layer comprises pigments, a second coating layer on the second side, and a second barrier coating layer on the second coating layer, which second barrier coating layer comprises pigments, wherein the coating layers and the barrier coating layers comprise a latex or a water-soluble polymer, wherein the first coating layer and the second coating layer are free of pigments, wherein the first barrier coating layer and the second barrier coating layer comprise pigments in an amount in a range from >40 wt % to <70 wt %, based on the dry solid content of the respective layer, and wherein the grammage of each of the first and second coating layer and of the first and second barrier coating layer is in a range from >1 g/m2 to <10 g/m2. The invention further relates to a method of manufacturing a respective packaging material and a packaging derived therefrom.