Cushioning Material with Hollow Microspheres for Multi-Impact Absorption
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Solution Overview
Problem
Conventional expanded polystyrene (EPS) used in helmet padding absorbs impact irreversibly, is sensitive to high temperatures, and has a non-negligible density, limiting its effectiveness for multiple impacts and durability in extreme conditions.
Innovation Solution
A composite material comprising a mixture of 2-part resin and hollow microspheres with a thermoplastic bonding agent, where non-expanded microspheres act as binding agents and expanded microspheres as fillers, providing an elastic energy-dispersion response without structural collapse, and including optional additives like pyrogenic silica and polyethylene fibers for improved flow and toughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If expanded polystyrene (EPS) is used for impact absorption, then impact protection is provided, but the material collapses irreversibly and cannot absorb subsequent impacts
Solution Approach 1:
The patent changes the physical state parameters of the material by using non-expanded microspheres that expand when heated in the molding process. This creates a cellular structure that can elastically deform and recover, enabling multi-impact capability while maintaining structural integrity through the reversible expansion/contraction mechanism of the closed-cell structure.
Solution Approach 2:
The invention combines non-expanded microspheres (which expand during molding), expanded microspheres (for immediate cushioning), and thermoplastic bonding agents to create a composite material with superior properties. This composite structure provides both the elastic recovery needed for multi-impact capability and the structural integrity required for durability.
2Reliability
If expanded polystyrene (EPS) is used for impact protection, then cushioning is provided, but the material becomes soft and loses effectiveness at high temperatures over 60°C
Solution Approach 1:
The patent utilizes the phase change and expansion properties of non-expanded microspheres during the thermoplastic molding process. The microspheres expand when heated, creating a stable cellular structure that maintains its mechanical properties across a wide temperature range, including high temperatures over 60°C, thereby providing temperature stability without sacrificing material firmness.
3Reliability
If expanded polystyrene (EPS) is used for impact absorption, then protection is achieved, but the density is non-negligible adding weight to the helmet
Solution Approach 1:
The invention changes the density parameter by incorporating non-expanded microspheres that expand during the molding process to create a highly porous, low-density cellular structure. This expanded structure provides effective impact absorption through energy dispersion while significantly reducing the overall density and weight of the protective material compared to conventional EPS.
Solution Approach 2:
The patent employs a porous material structure created by the expansion of non-expanded microspheres during molding. This porous cellular structure reduces material density and weight while maintaining impact absorption capability through the energy-dispersing cellular architecture, allowing the helmet to be lighter without compromising protection.
4Reliability
If non-expanded microspheres are used as binding agents, then the material achieves shape memory and multi-impact capability, but the processing complexity increases
Solution Approach 1:
The patent exploits the phase transition and thermal expansion properties of non-expanded microspheres during the thermoplastic molding process. The microspheres expand when heated above their glass transition temperature, creating the desired cellular structure and shape memory effects. This phase transition mechanism is integrated into the standard thermoplastic molding process, allowing shape memory capability to be achieved without significantly increasing processing complexity.
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 material achieves enhanced impact absorption with reduced density, maintaining performance across multiple impacts and offering shape memory and improved processing ease, resulting in lighter, more effective protective helmets with lower G and HIC values compared to standard EPS.
Implementation Method 1
the non-expanded microspheres or spheres are in plastic material, and are closed spheres. They are hollow and full of gas which expands when heated making the sphere dilate and reducing the overall density of the material
Implementation Method 2
With the heat of the mould, where the compound hardens, all the microspheres expand (though the expanded ones less)
Implementation Method 3
viscoelastic: if they were only viscose they would not return to position making the material multi-impact, while if they were only elastic they would not absorb energy
Data Source
AI summary
To mould light, impact cushioning and multi-impact objects a material is disclosed composed in weight of 20-50% of expanded particles and 80-50% of binding component, the particles being in plastic material, of closed shape, hollow and filled with gas.