Castable Energy Absorbing Material for Thin Flexible Protection
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Solution Overview
Problem
Existing energy-absorbing materials for protective clothing, such as gloves and footwear, are either too rigid or lack sufficient protection when thin, and current manufacturing methods require expensive tooling and complex processes.
Innovation Solution
A method using a liquid-castable polymer system combined with shear thickening additives, such as dilatants or silicone master batches, to create an energy-absorbing material that can be cast onto protective items and integrated into clothing, offering improved flexibility and impact protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If hard shells are used for protection, then impact protection is improved, but flexibility deteriorates
Solution Approach 1:
The patent uses strain rate sensitive materials that change their mechanical properties based on the rate of deformation. Under normal conditions, the material remains soft and flexible, but under impact conditions (high strain rate), it transitions to a rigid state providing protection. This dynamic parameter change resolves the contradiction between flexibility and impact protection.
Solution Approach 2:
The patent combines strain rate sensitive materials with geometry or tensile layers to create a composite structure that exhibits both flexibility and impact protection. The composite material leverages the unique properties of each component to achieve both softness for flexibility and hardness for protection when needed.
2Ease of operation
If soft shells based on foams are used for protection, then flexibility is improved, but impact protection deteriorates when below 6 mm in thickness
Solution Approach 1:
The patent employs strain rate sensitive materials that remain soft and flexible under normal conditions but transition to a rigid protective state under impact. This allows thin sections to provide adequate impact protection without sacrificing flexibility, eliminating the need for thick foam layers.
Solution Approach 2:
The material undergoes a phase transition from a soft, flexible state to a rigid, protective state when subjected to impact forces. This phase change enables the material to provide impact protection in thin sections while maintaining flexibility during normal use.
3Manufacturing precision
If injection moulding is used to manufacture energy absorbing materials, then manufacturing precision is improved, but device complexity and tooling cost increase dramatically
Solution Approach 1:
The patent adopts liquid casting as a simpler, more cost-effective manufacturing method compared to injection moulding. While injection moulding requires expensive hardened steel tools, liquid casting uses softer, cheaper tooling that can be easily modified for different designs and sizes, making it economically viable for producing protective clothing in multiple variations.
Solution Approach 2:
The patent changes the manufacturing approach from high-pressure injection moulding to low-pressure liquid casting. This parameter change in the manufacturing process reduces tooling complexity and cost while still achieving the required manufacturing precision for protective clothing components.
4Manufacturing precision
If injection moulding is used to manufacture energy absorbing materials, then manufacturing precision is improved, but manufacturing cost increases due to multiple tools needed for different sizes
Solution Approach 1:
The patent uses liquid casting with softer, cheaper tooling materials that can be easily adapted for different sizes and designs. This eliminates the need for multiple expensive hardened steel tools required by injection moulding, significantly reducing manufacturing costs for producing protective clothing in various sizes.
Solution Approach 2:
The liquid casting process and tooling can be used universally across multiple product variations and sizes. A single casting setup can produce different sizes and designs of protective clothing components, making the manufacturing system multi-functional and cost-effective compared to size-specific injection mould tools.
5Ease of manufacture
If liquid casting rubber or TPU is used in low pressure tooling, then manufacturing cost is reduced, but energy absorption performance deteriorates
Solution Approach 1:
The patent combines liquid-castable polymer systems with shear thickening additives to create a composite material that maintains the ease of manufacture from liquid casting while dramatically improving energy absorption performance. The shear thickening additive provides impact protection by increasing viscosity under high strain rate conditions.
Solution Approach 2:
The patent integrates shear thickening materials into the liquid-castable polymer system to create a composite that exhibits both the manufacturing advantages of liquid casting and the energy absorption properties of shear thickening materials. This composite approach resolves the contradiction between ease of manufacture and energy absorption performance.
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 resulting material provides enhanced energy absorption and impact protection while being soft and flexible, with a Shore D hardness range of 30 to 60, and can be produced using low-pressure tooling, reducing manufacturing costs and tooling complexity.
Implementation Method 1
a liquid-castable polymer system, combined with B) a shear thickening additive
Data Source
Figure 1
AI summary
A composition comprising a liquid-castable polymer system combined with solid particles of a shear thickening additive; an energy absorbing material formed from the composition; and an article comprising the energy absorbing material on a substrate, for example, a glove (1) including the material of the invention as energy absorbing elements (2a, 2b, 2c, 3a, 3b, 3c, 3d, 3e) incorporated onto the surface (4) of a textile substrate to provide protection over the metacarpophalangeal and proximal interphalangeal joints.