Biodegradable Packaging Coating Blend for Faster Extrusion 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 introduces issues like pinholes and poor heat-sealability, while high melt index polylactide is too viscous for extrusion.
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, and enabling higher machine speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If low melt index polylactide is used for coating, then adhesion to fibrous substrate is improved, but machine speed decreases and pinholes remain in the extruded layer
Solution Approach 1:
The patent changes the melt index parameter of polylactide from low (conventional) to high (≥30 g/10min), which fundamentally alters the extrusion behavior and machine speed capability while maintaining acceptable adhesion through optimized blend composition
Solution Approach 2:
The patent creates a composite material system by blending high melt index polylactide with polybutylene succinate (PBS) and other polymers, where the combination of materials compensates for the lower adhesion of high melt index PLA alone, achieving both high machine speed and sufficient adhesion
2Productivity
If high melt index polylactide is used for coating, then machine speed increases, but the material becomes too viscous for extrusion
Solution Approach 1:
The patent optimizes the melt index parameter to be ≥30 g/10min (higher than conventional), which reduces viscosity enough to enable extrusion at high machine speeds while maintaining the benefits of high-speed production
Solution Approach 2:
The patent uses composite blending of high melt index polylactide with PBS and other polymers to achieve the right balance of viscosity and extrudability, where the blend composition compensates for the high viscosity of pure high melt index PLA
3Reliability
If polylactide is used as coating polymer, then biodegradability is achieved, but heat-sealability deteriorates
Solution Approach 1:
The patent creates a composite coating layer blending polylactide with polymers having good heat-sealability (such as polyethylene, polypropylene, or their copolymers), where the blend combines the biodegradability of PLA with the heat-sealability of the other polymers
Solution Approach 2:
The patent optimizes the composition parameters of the polymer blend, controlling the ratios of PLA to other polymers, and adjusts processing parameters to achieve both biodegradability and adequate heat-sealability in the composite coating
4Ease of manufacture
If polyolefins are used for coating, then heat-sealability is improved, but biodegradability is lost
Solution Approach 1:
The patent uses composite blending where polylactide (biodegradable) is combined with polyolefins or their copolymers in controlled ratios, maintaining the biodegradability character of the packaging while incorporating the heat-sealability benefits of polyolefins
Solution Approach 2:
The patent carefully controls the composition parameters of the blend, limiting the content of non-biodegradable polyolefin components while maximizing the biodegradable PLA content, and optimizes processing parameters to achieve heat-sealability without sacrificing biodegradability
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, allowing for higher machine speeds and improved manufacturing efficiency without compromising environmental sustainability.
Implementation Method 1
wherein the components of the blend being melted and blended in connection with an extrusion step
Implementation Method 2
a method of manufacturing a biodegradable packaging material comprising extrusion onto a fibrous substrate one or more polymer coating layers
Data Source
AI summary
A biodegradable packaging material, a method of manufacturing the same, as well as products made of the material wherein the manufacture comprises extrusion onto a fibrous substrate one or mote polymer coating layers including at least one layer 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 machine speed in extrusion and maintaining good adhesiveness to the substrate and wood heat-sealability of the coating. The products include disposable drinking cups and board trays, as well as sealed carton packages for solids and liquids.