Depolymerized Polysaccharide Barrier Coating for Paper
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Solution Overview
Problem
Existing barrier coatings for paper, cardboard, and moulded pulp face challenges due to high viscosity, lack of compliance with environmental regulations, and insufficient barrier effects against oxygen, mineral oil, edible oil, and fatty substances, particularly when using natural, unmodified polysaccharides.
Innovation Solution
Development of low-viscosity aqueous solutions of depolymerized, natural polysaccharides such as guar, alginate, and carrageenan, with viscosities below 5,000 mPa·s, applied at 10% solids content, ensuring compliance with European Regulation (EU) 2019/904 and providing excellent barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If natural polysaccharides (guar, alginate, carrageenan) are used as barrier coating materials, then environmental compliance and biodegradability are improved, but viscosity becomes excessively high making application difficult
Solution Approach 1:
The patent applies parameter changes by modifying the molecular weight of natural polysaccharides through controlled depolymerization. This reduces the viscosity of coating solutions from excessively high levels (e.g., guar gum at 4,000-8,000 mPa·s) to application-friendly levels (below 1,500 mPa·s), while preserving the barrier functionality and environmental compliance of the natural polymers.
2Ease of operation
If highly diluted polysaccharide solutions are used to reduce viscosity, then ease of application is improved, but the barrier effect is dramatically reduced
Solution Approach 1:
The patent resolves this contradiction by changing the molecular weight parameter of the polysaccharides through depolymerization. This allows the use of concentrated solutions (high solids content) with low viscosity, maintaining both ease of application and strong barrier effect. The depolymerized structures provide sufficient barrier performance at higher concentrations without requiring excessive dilution.
3Reliability
If native, unmodified polysaccharides are used, then compliance with European Regulation (EU) 2019/904 is improved, but viscosity and application difficulty worsen
Solution Approach 1:
The patent applies preliminary action by performing depolymerization of natural polysaccharides before the coating application process. This pre-treatment modifies the molecular weight and viscosity characteristics of the polymers in advance, making them suitable for standard coating equipment while maintaining their status as natural, unmodified substances that comply with European Regulation (EU) 2019/904.
4Device complexity
If conventional coating units are used with high-viscosity polysaccharide solutions, then equipment simplicity is maintained, but coating quality and barrier performance worsen
Solution Approach 1:
The patent applies parameter changes by modifying the viscosity parameter of polysaccharide solutions through depolymerization. This enables the use of conventional coating units (size press, engraving roll, blade coater, air knife, curtain coater, spray application) to achieve high-quality, uniform coatings with excellent barrier performance, eliminating the need for specialized equipment while improving coating quality.
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 achieves effective barrier performance against oxygen, mineral oil, edible oil, and fatty substances while maintaining flexibility, adhering to environmental regulations, and allowing application on paper, cardboard, and moulded pulp without chemical modification.
Implementation Method 1
The barrier coating is used to reduce the diffusion of oxygen, mineral and food oils, and fatty substances through the paper or cardboard
Data Source
AI summary
The invention relates to natural, depolymerized, powdered polymers and mixtures thereof and aqueous solutions prepared therefrom for the production of a barrier coating on paper, cardboard, or moulded pulp. The barrier coating is used to reduce the diffusion of oxygen, mineral and food oils, and fatty substances through the paper, cardboard or moulded pulp. A 2 wt. % of the aqueous solutions has a viscosity in a range of from 1 to 100 mPa·s as measured with a rotational viscometer at room temperature and 20 rotations per minute. The natural, depolymerized, powdered polymers are selected from a group of guar gum, tara gum, sesbania gum, locust bean gum, alginates, or carrageenans such that the barrier coating is free from halogenated polymers.