Coated Substrate Using MFC and CMC for Oxygen Barrier
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Solution Overview
Problem
Existing packaging materials face challenges in providing an efficient and environmentally friendly oxygen barrier, as current coating processes are energy-intensive and difficult to integrate into existing paper or board production lines, and often result in materials with high carbon footprints and recyclability issues.
Innovation Solution
A process for producing a coated substrate with cellulosic fibers using a coating composition of microfibrillated cellulose (MFC) and carboxymethyl cellulose (CMC) applied to a wet substrate, allowing for on-line integration with existing paper or board production processes, reducing energy consumption, and enhancing oxygen barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If extrusion coating is used to provide oxygen barrier, then barrier performance is improved, but energy consumption increases due to multiple drying steps and integration difficulty
Solution Approach 1:
The patent combines the coating application and drying operations into a single integrated step by applying coating composition directly to the substrate on the paper machine, eliminating the need for separate drying sections that would be required in conventional extrusion coating processes
Solution Approach 2:
The coating composition is applied to the substrate while it is still on the paper machine before final drying, allowing the coating to be deposited in advance and dried simultaneously with the substrate in the existing drying sections, rather than requiring post-production drying
2Reliability
If aluminium foil is applied to provide barrier, then barrier performance is improved, but environmental impact increases due to carbon footprint and recyclability issues
Solution Approach 1:
The patent changes the material composition parameter from aluminium foil to organic-based coating materials (such as polyethylene, polypropylene, or starch-based coatings), transforming the barrier layer into an environmentally friendly alternative that is compatible with recyclable paper and board substrates
Solution Approach 2:
The patent uses thin, disposable organic coating layers that can be applied in small amounts (0.1-10 µm thickness) to provide effective barriers, replacing the need for thicker, more persistent aluminium foil layers that are difficult to recycle
3Reliability
If coating composition with major amount of colloidal polymer particles is used, then barrier performance is improved, but environmental friendliness decreases
Solution Approach 1:
The patent uses composite coating compositions that combine organic polymers (such as polyethylene, polypropylene, or starch derivatives) with cellulosic fibres, creating a biodegradable and environmentally friendly composite material that provides effective oxygen and moisture barriers
Solution Approach 2:
The patent employs coating materials that are designed to be discarded with the packaging material in a single recycling stream, allowing the entire package (substrate plus coating) to be recycled together as paper or board, rather than requiring separation of persistent polymer coatings
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 process enables the production of a high-quality, energy-efficient, and environmentally friendly packaging material with improved oxygen barrier properties, reducing the need for additional drying sections and equipment investments, while maintaining the quality of existing barrier methods.
Implementation Method 1
applying a coating composition to the first substrate in a total amount of over 10 g/m2 and less than 40 g/m2 The coating composition comprises microfibrillated cellulose (MFC) and carboxymethyl cellulose (CMC)
Data Source
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Figure 3
AI summary
The present invention relates to process for the production of a coated substrate comprising cellulosic fibres, the process comprising the steps of: i) providing a first substrate comprising cellulosic fibres and having a dry content of less than 50%; ii) applying a coating composition to the first substrate in an amount of more than 5 g/m2,,calculated as dry weight of the coating composition, wherein the coating composition comprises: - microfibrillated cellulose (MFC), and - optionally a water retention agent selected from carboxymethyl cellulose (CMC), anionic polyacrylamide (A-PAM),sodium polyacrylates, polyacrylic acid derivatives, guar gum, alginate, MFC prepared from carboxymethylated fibers, MFC prepared from oxidized fibers, MFC preparedby CMC- functionalised fibers, and/or combinations thereof; and iii) mechanically dewatering the first substrate. The present process provides an energy efficient coating process which can be performed online.