Cellulose-Based Packaging Sandwich Structure for Moisture and Gas Barriers
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Solution Overview
Problem
Existing cellulose-based packaging materials face challenges in achieving adequate moisture and gas barrier properties due to structural gaps and voids, leading to high transmissibility, and incorporating non-sustainable barrier layers increases costs and complexity.
Innovation Solution
A three-ply sandwich structure is formed using a hybrid paper machine, where micro- and nano-scale cellulose fibers (MFC and CNF) are evenly distributed and immobilized within a cellulose-based matrix via a foam-forming method, ensuring even distribution and preventing cracks and pinholes during dewatering and drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If paper or cellulose-based substrates are used as packaging materials, then sustainability is improved, but moisture and gas barrier properties deteriorate due to structural gaps and voids
Solution Approach 1:
The invention combines cellulose-based fibers with micro- and nano-scale cellulose products (MFC and NFC) to create a composite paper substrate. The MFC and NFC form a dense network that fills structural gaps and voids in the cellulose matrix, providing enhanced moisture and gas barrier properties while maintaining the sustainability of using only cellulose-based materials.
2Object-affected harmful factors
If non-paper barrier layers (polymeric films or foils) are incorporated to improve barrier properties, then moisture and gas barrier characteristics are improved, but cost increases and sustainability deteriorates
Solution Approach 1:
The invention changes the structural parameters of the cellulose-based substrate by incorporating MFC and NFC, which have different physical dimensions and arrangement characteristics compared to conventional cellulose fibers. This structural parameter change creates a denser matrix with reduced porosity, achieving barrier properties previously only attainable with polymeric films.
3Object-affected harmful factors
If known surface coating methods are used to apply MFC and NFC onto paper, then barrier properties are attempted to be improved, but drying effectiveness deteriorates due to high water content causing cracks and pinholes
Solution Approach 1:
The invention merges MFC and NFC directly into the papermaking process rather than applying them as a separate coating layer. The micro- and nano-scale cellulose products are incorporated into the fiber slurry and formed together with the base paper in the paper machine, ensuring uniform distribution and avoiding the drying-induced cracking and pinholes associated with surface coating methods.
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 a cellulose-based packaging material with enhanced gas and aroma barriers, reducing material and manufacturing costs while maintaining structural integrity, suitable for dry and odor-mitigating storage without relying on plastic films or foils.
Implementation Method 1
micro- and nano-scale cellulose fibers (MFC and CNF) are evenly distributed and immobilized within a cellulose-based matrix via a foam-forming method
Data Source
AI summary
A cellulose-based packaging material has a multi-layer structure that includes a barrier layer with at least one of microfibrillated cellulose (MFC) and cellulose nanofibril (CNF) that provides enhanced moisture and/or oxygen or other gas barrier properties. The other layers, e.g., outer layers, of the material's multilayer structure may be cellulose-based and the entire material may be devoid of polymeric or metallic films or foils. The material may be implemented as a sandwich structure with an interior MFC and/or CNF film as the barrier layer and cellulose-based outer layers that immobilize the MFC and/or CNF film during the material's dewatering and drying procedures. Nano-scale cellulose products delivering the MFC and/or CNF may be incorporated into a foamed MFC and/or CNF product upstream of a paper machine headbox, so that the headbox(es) receives a volume of foamed MFC and/or CNF product for forming the barrier layer and at least two volumes of non-foamed and non-MFC and/or CNF cellulose-based feedstock for forming the outer layers.