Biodegradable Starch Pellets Foamed by Irradiation
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Solution Overview
Problem
Conventional foam materials like EPS are not biodegradable and pose environmental issues, and starch-based foams lack the mechanical properties and self-sealing capabilities necessary for effective protective packaging.
Innovation Solution
Development of biodegradable low-density, self-sealing pellets made from high viscosity starch with a porous internal structure and low porous external skin, capable of expanding uniformly under irradiation to produce foamed articles with thin-walled cells and suitable density for protective packaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If starch-based foam materials are prepared by extrusion processes with large quantities of water, then expansion takes place directly at the outlet, but the intrinsic viscosity must be between 0.5 and 1.5 dl/g resulting in very high molecular weight reduction and resiliency far less than EPS
Solution Approach 1:
The patent changes the key parameter of intrinsic viscosity to be greater than 1.5 dl/g, which is fundamentally different from conventional starch-based foams (0.5-1.5 dl/g). This parameter change preserves molecular weight and achieves low density foams with resiliency comparable to EPS without requiring extreme molecular weight reduction
Solution Approach 2:
The patent utilizes phase transition of water (liquid to vapor) as the expansion mechanism. Water is incorporated into the starch matrix and then rapidly vaporized during extrusion, causing the material to expand and form foam structure. This phase transition approach eliminates the need for chemical blowing agents and achieves sustainable foam production
2Reliability
If conventional starch-based foam materials are used, then they are biodegradable and from renewable sources, but they show high sensitivity to humidity and lack self-sealing capability
Solution Approach 1:
The patent changes the intrinsic viscosity parameter to greater than 1.5 dl/g, which fundamentally alters the material's response to humidity. This higher viscosity creates a more stable molecular structure that resists humidity-induced degradation, eliminating the high sensitivity to humidity that plagues conventional starch foams
Solution Approach 2:
The patent creates a composite material system combining high viscosity starch with specific molecular weight characteristics. This composite approach maintains the biodegradability and renewable source advantages of starch while adding humidity resistance and self-sealing capability through the optimized molecular structure
3Strength
If EPS is used for protective packaging, then mechanical properties and cushioning characteristics are excellent, but the material accumulates and poses environmental disposal problems
Solution Approach 1:
The patent creates a biodegradable foam material that can be disposed of after use, eliminating the environmental accumulation problem of traditional EPS. The material is designed to perform its protective function effectively and then decompose naturally, replacing the persistent synthetic polymer with a sustainable alternative
Solution Approach 2:
The patent changes the fundamental parameter of material composition from synthetic polymer (EPS) to high viscosity starch-based material. This parameter change maintains the mechanical properties and cushioning characteristics needed for protective packaging while fundamentally solving the environmental persistence issue
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 pellets achieve a density and mechanical properties comparable to EPS, enabling them to be used as a sustainable alternative in protective packaging without the environmental drawbacks of traditional materials.
Implementation Method 1
the water contained within them to be heated and quickly evaporated causing expansion of the pellets
Implementation Method 2
the water contained within them to be heated and quickly evaporated causing expansion of the pellets
Data Source
AI summary
This invention relates to biodegradable starch-based pellets which foamable by irradiation, which are particularly suitable for the manufacture of foam articles, characterised in that they have a porous structure with a low porous external skin. This invention also relates to foam articles obtained from these.