Ambient-Cure Thermoset Elastomer Additive Manufacturing
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Solution Overview
Problem
Current additive manufacturing methods for thermoplastic polymers require heating or irradiation, limiting their applicability and complexity, and are not suitable for forming thermoset elastomeric parts without these processes.
Innovation Solution
A method using a prepolymer and filler system that reacts at ambient temperature, allowing for the formation of thermoset elastomeric parts without heating, with specific rheological properties enabling the retention of shape and adhesion during extrusion, such as high viscosity at low shear and shear thinning at higher shear rates, and the use of isocyanate terminated prepolymers and carbon black fillers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If heating or irradiation is used in additive manufacturing, then thermoplastic polymers can be melted and extruded, but the process becomes complex and limited to specific material types
Solution Approach 1:
The patent replaces thermal or optical fields (heating/Irradiation) with a mechanical field (shear force from extrusion through a nozzle). The prepolymer is extruded through a nozzle at a shear rate that induces crosslinking, eliminating the need for heating or irradiation equipment while achieving the same manufacturing function.
Solution Approach 2:
The patent changes the fundamental parameter for initiating polymer transformation from temperature or energy input to shear rate. By controlling the shear rate during extrusion, the prepolymer crosslinks in situ without requiring thermal or optical energy, thereby simplifying the manufacturing process and expanding material versatility.
2Strength
If thermoplastic polymers are used in additive manufacturing, then parts can be formed by melting and extrusion, but the parts lack elastomeric properties and dimensional control
Solution Approach 1:
The patent uses a composite material system consisting of prepolymer and crosslinking agent. This composite allows the material to exhibit both processability (like thermoplastics) and final elastomeric properties (like rubbers). The crosslinking reaction creates a thermoset network that provides both strength and dimensional stability without requiring complex support structures.
3Adaptability or versatility
If heating is required for extrusion, then thermoplastic materials can be processed, but the process cannot form thermoset elastomeric parts
Solution Approach 1:
The patent substitutes thermal energy with mechanical shear energy. The prepolymer is extruded through a nozzle at a controlled shear rate that triggers crosslinking. This allows thermoset elastomeric parts to be formed without heating, expanding material versatility while eliminating temperature control requirements.
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
Enables the creation of complex thermoset elastomeric parts with high tensile elongation, suitable for mitigating noise, vibration, or harshness issues, without the need for heating or irradiation, and with improved dimensional control and uniformity.
Implementation Method 1
a prepolymer and a filler where the prepolymer reacts under the environment it is dispensed to or with a second component simultaneously mixed and dispensed with it and forms a cross-linked or thermoset matrix
Implementation Method 2
specific rheological properties enabling the retention of shape and adhesion during extrusion, such as high viscosity at low shear and shear thinning at higher shear rates
Data Source
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AI summary
An additive elastomeric manufactured part having an elongation at break of at least 50% may be made by a method comprising the following. A material comprising a prepolymer and filler is first dispensed through a nozzle to form an extrudate deposited on a base. The base, nozzle or combination thereof is moved while dispensing the material so that there is horizontal displacement between the base and nozzle in a predetermined pattern to form an initial layer of the material on the base. Subsequent layers are then formed on the initial layer by repeating the dispensing and movement on top of the initial layer and layers that follow.