Dynamically Crosslinked Thermoplastic Elastomer Recycling
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Solution Overview
Problem
Existing crosslinked rubbers and thermoset materials are difficult to recycle, leading to increased manufacturing costs due to scrap materials generated during production, and there is a need for recyclable products after their useful life.
Innovation Solution
A method of creating dynamically crosslinked thermoplastic materials by partially crosslinking an elastomer composition and then mixing it with a thermoplastic polymer composition at a higher temperature to form a dispersed phase of crosslinked elastomer domains within a thermoplastic matrix, preventing the transfer of non-polymeric components and allowing for further shaping and recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If crosslinked rubbers and thermoset materials are used to achieve excellent physical properties, then resilience and durability are improved, but recyclability deteriorates
Solution Approach 1:
The patent changes the chemical state of the elastomer from fully crosslinked (thermoset) to dynamically crosslinked (thermoplastic), allowing the material to transition between solid and melt states. This parameter change enables both excellent physical properties when solid and recyclability when melted, resolving the contradiction between resilience and recyclability
Solution Approach 2:
The patent creates a composite material system combining thermoplastic resin matrix with dynamically crosslinked elastomer domains. This composite structure allows the material to exhibit both the resilience of crosslinked rubbers and the recyclability of thermoplastics, as the thermoplastic matrix can be remelted and reprocessed
2Reliability
If crosslinked rubbers and thermoset materials are used to achieve excellent physical properties, then durability is improved, but manufacturing cost increases due to scrap materials
Solution Approach 1:
By changing the material from thermoset to dynamically crosslinked thermoplastic, the patent enables scrap material to be remelted and reprocessed multiple times without degradation, eliminating waste and reducing manufacturing costs while maintaining durability
Solution Approach 2:
The patent enables recovery and reuse of scrap material through remelting and reprocessing, converting what would be discarded waste into reusable feedstock, thereby reducing loss of substance and manufacturing cost
3Ease of manufacture
If thermoplastic resin and rubber are melt mixed and cured to form dynamically crosslinked materials, then recyclability is improved, but component transfer between phases occurs
Solution Approach 1:
The patent applies preliminary crosslinking to the elastomer before mixing with thermoplastic resin, creating stable elastomer domains that resist component transfer during subsequent processing and recycling, thus maintaining compositional stability while enabling recyclability
Solution Approach 2:
The patent uses the crosslinked elastomer domains as intermediaries that prevent direct contact and transfer between thermoplastic components, acting as a barrier that maintains compositional stability during recycling processes
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 dynamically crosslinked thermoplastic materials exhibit excellent physical properties, including resilience, thermal properties, and sound dampening, with the ability to be recycled, reducing waste and manufacturing costs.
Implementation Method 1
partially crosslinking an elastomer composition at a first crosslinking temperature to form a thermoplastic, partially crosslinked elastomer composition
Implementation Method 2
heating the thermoplastic polymer composition and the thermoplastic, partially crosslinked elastomer composition to a second crosslinking temperature higher than the first crosslinking temperature
Implementation Method 3
wherein the thermoplastic polymer composition is liquid at the second crosslinking temperature
Implementation Method 4
continuously mixing the mixture while further crosslinking the elastomer composition to form a thermoplastic material having a dispersed phase of crosslinked elastomer composition in the thermoplastic polymer composition
Data Source
AI summary
A method for making a thermoplastic material includes: (a) partially crosslinking an elastomer composition at a first crosslinking temperature to form a thermoplastic, partially crosslinked elastomer composition; (b) mixing a thermoplastic polymer composition with the thermoplastic, partially crosslinked elastomer composition and heating the mixture to a second crosslinking temperature higher than the first crosslinking temperature, wherein the thermoplastic polymer composition is liquid at the second crosslinking temperature; and (c) continuously mixing the mixture while further crosslinking the elastomer composition to form a thermoplastic material having a dispersed phase of crosslinked elastomer composition in the thermoplastic polymer composition. The elastomer composition may include an elastomer compounded with a curing agent and optionally additional components. A thermoplastic material resulting from this process may be molded or shaped by any method used for forming thermoplastic materials into articles, such as molding, extrusion, or thermoforming.