Foamed Layered PLA Structures With Smooth Skins and Recyclability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional plastic foaming technologies face issues such as friability, difficulty in recycling, environmental concerns from chemical blowing agents, and unsuitable surface properties for packaging, particularly in durable and food packaging applications, where foamed plastics often lack durability and recyclability.
Innovation Solution
The development of layered structures in reduced density plastics, which can be produced with or without integral skins, using additives and fillers that enhance gas diffusion, allowing for high crystallinity and improved properties like moisture and oxygen resistance, and utilizing biodegradable polymers like PLA for compostable and heat-resistant structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional chemical blowing agents are used to produce foam plastic, then insulation and cushioning performance are improved, but the material becomes friable and forms small pellets that are difficult to separate from waste streams
Solution Approach 1:
The patent changes the fundamental parameter of the foaming agent from chemical blowing agents to carbon dioxide gas. This parameter change transforms the foam structure into larger cells that are less friable and easier to separate from waste streams, while maintaining insulation and cushioning performance through the gas-filled cellular structure
Solution Approach 2:
The patent creates a porous foam structure using carbon dioxide saturation and solid-state foaming. The resulting material has a controlled cellular morphology with larger cells that provide insulation and cushioning while being less prone to fragmentation into difficult-to-separate pellets compared to chemically-foamed materials
2Quantity of substance
If conventional extrusion foaming is used to reduce material density, then density reduction is achieved, but the surface becomes cellular and unattractive for high-quality graphics and coatings
Solution Approach 1:
The patent applies local quality by creating a dual-layer structure where the interior maintains a cellular foam structure for density reduction, while the exterior surface is treated or selected to provide a smooth, non-cellular finish suitable for high-quality graphics and coatings. This allows different regions of the material to have different properties optimized for their specific functions
Solution Approach 2:
The patent segments the foam structure into distinct cellular regions and surface regions. The cellular structure provides bulk density reduction, while the surface layer (either through selective foaming or post-processing) provides the smooth finish needed for graphics and coatings, separating the conflicting requirements into different spatial zones
3Productivity
If fluorocarbons and chlorofluorocarbons are used as blowing agents, then foam production is achieved, but environmental harm is caused and plastic recyclability is compromised
Solution Approach 1:
The patent converts the harmful chemical blowing agents into a beneficial alternative by using carbon dioxide, an environmentally benign gas. This substitution eliminates the environmental harm and recyclability issues associated with fluorocarbons and chlorofluorocarbons while maintaining effective foam production through CO2 saturation and solid-state foaming mechanisms
Solution Approach 2:
The patent changes the chemical parameter of the blowing agent from harmful fluorocarbons to benign carbon dioxide. This parameter change eliminates environmental contamination and preserves plastic recyclability while achieving effective foam production through the physical dissolution and expansion of CO2 in the polymer matrix
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 creation of lightweight, high-strength, and compostable plastic products with improved structural efficiency and print quality, reducing environmental impact and production costs while providing superior performance in packaging applications.
Implementation Method 1
additives, blends, or fillers, which may include polymer additives, polymer blends of thermoplastics including bioplastics, solid fillers, or additives which may allow high rates of gas diffusion into and out of thermoplastics
Implementation Method 2
a foaming process may involve saturating a polymer such as PLA with high levels of gas, and then heating, which may produce a reduced density plastic having high levels of crystallinity
Implementation Method 3
heating, which may produce a reduced density plastic having high levels of crystallinity
Data Source
AI summary
Disclosed, among other things, are ways to manufacture layered structures. In one embodiment, a foaming process may produce layered structures in reduced density plastics with or without integral skins. In another embodiment, a foaming process may produce deep draw structures in reduced density plastics with or without integral skins. In yet another embodiment, a foaming process may utilize additives, blends, or fillers, for example. In yet another embodiment, a foaming process may involve saturating a semi-crystalline polymer such as Polylactic Acid (PLA) with high levels of gas, and then heating, which may produce a reduced density plastic having high levels of crystallinity. These processes may be used to generate products with layered structures.