Biodegradable Packaging Coating Blend for Fast Extrusion and Sealing
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Solution Overview
Problem
Current biodegradable packaging materials face challenges with extrudability, adhesion to fibrous substrates, and heat-sealability due to the use of low melt index polylactide, which limits machine speed and compromises environmental sustainability.
Innovation Solution
A method involving the extrusion of polymer coating layers onto fibrous substrates using a blend of high melt index polylactide (20-95 wt-%) and polybutylene succinate (5-80 wt-%) with optional polymeric additives, allowing for improved adhesion and heat-sealability while maintaining machine speed and biodegradability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If low melt index polylactide is used for coating, then adhesion to fibrous substrate improves, but extrusion temperature must be increased and machine speed decreases
Solution Approach 1:
The patent changes the melt index parameter of polylactide from low (conventional) to high (at least 25 g/10min), which fundamentally alters the extrusion behavior and enables higher machine speeds while maintaining coating quality and adhesion properties
Solution Approach 2:
The patent creates a composite coating material by blending high melt index polylactide with polybutylene adipate terephthalate (PBAT) and other polyesters, combining the adhesion benefits of PLA with the processability and flexibility advantages of the blended polymers to achieve both good adhesion and high machine speed
2Productivity
If high melt index polylactide is used, then machine speed improves, but extrudability deteriorates due to high viscosity
Solution Approach 1:
The patent formulates a composite polymer blend containing high melt index polylactide (at least 25 g/10min), polybutylene adipate terephthalate (PBAT), and other polyesters in specific proportions, where the blended polymers work synergistically to reduce overall viscosity and improve extrudability while maintaining the high machine speed capability provided by the high melt index PLA
Solution Approach 2:
The patent optimizes the compositional parameters of the polymer blend, specifically controlling the ratios of high melt index PLA, PBAT, and other polyesters, to achieve the desired balance between viscosity (for extrudability) and processing speed (for productivity)
3Reliability
If polyolefins are used for coating, then heat-sealability and moisture barrier improve, but biodegradability is lost
Solution Approach 1:
The patent develops a biodegradable composite coating material blending high melt index polylactide with polybutylene adipate terephthalate and other biodegradable polyesters, achieving heat-sealability and moisture barrier properties comparable to polyolefin coatings while maintaining full biodegradability and environmental sustainability
Solution Approach 2:
The patent replaces persistent polyolefin coatings with biodegradable polymer blends that provide equivalent functional performance (heat-sealability, moisture barrier) but decompose naturally after use, aligning with sustainable packaging requirements for disposable applications
4Object-generated harmful factors
If polylactide coating is used, then biodegradability is maintained, but heat-sealability is poor due to high melting point
Solution Approach 1:
The patent creates a composite polymer blend incorporating high melt index polylactide with polybutylene adipate terephthalate and other polyesters in optimized ratios, where the blended polymers lower the effective melting point and improve heat-sealability while preserving the biodegradability inherent in the polylactide-based system
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 enhances extrudability, adhesion, and heat-sealability of biodegradable packaging materials, enabling higher machine speeds and improved manufacturing efficiency while preserving environmental sustainability.
Implementation Method 1
the components of the blend being melted and blended in connection with the extrusion step
Implementation Method 2
immediately followed by extrusion of the melt onto the fibrous substrate
Data Source
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AI summary
The invention provides a biodegradable packaging materi- al, a method of manufacturing the same, as well as products made of the material. The manufacture comprises extrusion onto a fibrous substrate (1) one or more polymer coating layers including at least one layer (2) of a polymer blend consisting of (i) 20–95 wt-% of polylactide having a high melt index of more than 35 g/10 min (210 °C; 2.16 kg), (ii) 5–80 wt-% of polybutylene succinate (PBS) or a biodegradable derivate thereof, and (iii) 0–5 wt-% of one or more polymeric additives. The components of the blend are melted and blended in connection with the extrusion step. The goal is to improve extrudability, increase ma- chine speed in extrusion and maintaining good adhesive- ness to the substrate and good heat-sealability of the coat- ing. The products include disposable drinking cups and board trays, as well as sealed carton packages for solids and liquids.