Cellulosic Container Sealing for Strong Bonds and Easy Repulping
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Solution Overview
Problem
Current methods for sealing paper packages using plastics and additives hinder the recycling process due to the difficulty in separating these materials during repulping, limiting the use of paper as a sustainable packaging alternative.
Innovation Solution
A method involving a sealing solution composed of water, starch, and polyol plasticizers is applied to cellulosic substrates, allowing for thermosealing that facilitates easy repulping and recycling, with the option to separate the sealing material from paper fibers if needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional plastics and additives are used for sealing paper packages, then sealing strength is improved, but the difficulty of separation during repulping increases
Solution Approach 1:
The patent extracts the sealing function from traditional plastic adhesives and implements it through a water-soluble polymer coating that can be easily removed during repulping. The sealing solution is applied to paper surfaces, dried to form a coating, and provides sealing strength when activated by moisture during the sealing process, yet dissolves completely in water during recycling operations.
Solution Approach 2:
The patent changes the chemical parameters of the sealing material from water-insoluble plastics to water-soluble polymers. This parameter change allows the sealing material to provide adequate sealing strength under dry conditions while being completely soluble in water during repulping, thus resolving the contradiction between sealing performance and recyclability.
2Ease of manufacture
If water-soluble polymers are used for sealing, then ease of repulping is improved, but sealing strength may be compromised
Solution Approach 1:
The patent applies preliminary action by pre-coating the paper surfaces with a water-soluble polymer solution that dries to form a stable coating. This coating provides the necessary sealing strength when moisture is introduced during sealing, while maintaining complete water solubility for easy removal during recycling. The preliminary coating step ensures both sealing performance and recyclability are achieved.
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
This approach enables the formation of strong, recyclable cellulosic-based packaging materials where the sealing solution can be easily removed or integrated into the recycling process, promoting sustainable packaging solutions.
Implementation Method 1
Aqueous sealing solutions including starch and a solid polyol plasticizer are applied to cellulosic substrates, dried, and then used to seal another cellulosic substrate
Data Source
AI summary
The disclosure relates to a method for sealing a cellulosic article in which a sealing solution is applied to one or more cellulosic substrates to form a seal between surfaces thereof. The sealing solution generally includes water, starch, a solid polyol plasticizer, and optionally a liquid polyol plasticizer. Coated surfaces of the cellulosic substrate(s) are then contacted under sufficient conditions to form the seal therebetween, for example after drying and/or with sufficient contact time, contact pressure, contact temperature, etc. The disclosure further relates to a corresponding sealed cellulosic article, for example as formed by the sealing method. The disclosure further relates to a method for recycling in which the sealed cellulosic article is re-pulped, with or without recovery of sealing composition components, then formed into a recycled cellulosic substrate.