Esterified Lignin Coating for Sustainable Packaging Barriers
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Solution Overview
Problem
Fiber-based packaging materials face limitations due to poor barrier properties and high moisture sensitivity, necessitating the development of bio-based polymers that can replace traditional petroleum-based materials while maintaining performance.
Innovation Solution
Esterification of lignin's hydroxyl groups with a mixture of fatty acids, specifically Tall Oil Fatty Acid (TOFA), to enhance film-forming properties and barrier capabilities, allowing for the creation of modified lignin with improved mechanical and physical properties suitable for applications in insulation, adhesion, binding, and composites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fiber-based packaging materials are used, then renewability and compostability are improved, but barrier properties and moisture resistance deteriorate
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of lignin through esterification with fatty acids. This chemical modification changes the hydrophilic properties of lignin to hydrophobic, thereby improving moisture resistance and barrier properties while maintaining the renewable and compostable characteristics of fiber-based packaging materials.
Solution Approach 2:
The patent creates composite materials by combining modified lignin with fiber-based packaging materials. The esterified lignin acts as a coating or barrier layer that provides improved moisture resistance and barrier properties to the otherwise hygroscopic fiber-based material, resulting in a composite with enhanced performance.
2Reliability
If bio-based polymers are used to replace petroleum-based materials, then environmental sustainability is improved, but film-forming properties and mechanical strength deteriorate
Solution Approach 1:
The patent improves film-forming properties by chemically modifying lignin through esterification. This parameter change in the molecular structure enhances the material's ability to form continuous films with adequate mechanical strength, while maintaining its bio-based and environmentally sustainable nature.
3Ease of manufacture
If technical lignin is used directly, then availability and cost are improved, but film-forming properties and barrier capabilities deteriorate
Solution Approach 1:
The patent applies parameter changes by esterifying technical lignin with fatty acids. This chemical modification transforms the poor film-forming properties of raw technical lignin into excellent film-forming capabilities, enabling the use of readily available technical lignin in high-performance applications.
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 modified lignin exhibits high and stable contact angles, effective barrier properties against oxygen and water vapor, and medium aroma barrier properties, making it suitable for use in packaging, insulation, and other applications, while being sourced from renewable forestry streams.
Implementation Method 1
esterification of hydroxyl groups in lignin with a carboxylic acid or a carboxylic acid anhydride
Implementation Method 2
The modified lignin exhibits high and stable contact angles, effective barrier properties against oxygen and water vapor
Data Source
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AI summary
In this study, commercially available softwood lignin was esterified with tall oil fatty acid (TOFA) and tested as barrier material in fiber-based packaging material. The modified lignin samples were applied with a bar coater forming an even coating on the paperboard substrate. A significant decrease in WVTR and OTR value was observed for paperboard coated with the modified lignin as well as pure TOFA used as a reference. In contrast to the TOFA coating, the modified lignin coatings exhibited a high and stable contact angle. The coating material did not affect the tensile strength of the paperboard. According to the results, the demonstration of the conversion of lignin into a value added product has been shown. Furthermore, the novel coating material shows promising properties for the development as sustainable barrier material in fiber-based packaging material to replace oil-placed barriers.