Conductive Polyurethane Elastomer Structure for Low Hardness Recovery
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Solution Overview
Problem
Conductive elastomers face challenges in achieving both low hardness and low compression set due to the trade-off relationship between these properties, particularly when a large amount of conductive filler is added.
Innovation Solution
A molded product comprising a polyurethane elastomer with a matrix-domain structure, where the matrix has a polycarbonate structure and the domains have a polyether structure, with the conductive filler predominantly distributed in the matrix to form conduction paths, allowing for a small amount of filler to achieve conductivity while minimizing hardness and compression set.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large amount of conductive filler is added to achieve conductivity, then electrical conductivity is improved, but hardness increases and compression set worsens
Solution Approach 1:
The patent applies local quality by creating distinct matrix and domain regions with different properties. The matrix contains the conductive filler to provide conductivity, while the domains provide softness and low compression set. This spatial differentiation allows different regions to have different functions - the matrix handles conductivity while the domains handle mechanical softness, resolving the contradiction between conductivity and hardness.
Solution Approach 2:
The patent uses composite materials by combining polyurethane elastomer with conductive filler particles to create a composite matrix. This composite structure allows the material to simultaneously achieve electrical conductivity from the filler and mechanical properties from the polyurethane matrix, resolving the contradiction between conductivity and hardness.
2Reliability
If a large amount of conductive filler is added to achieve conductivity, then electrical conductivity is improved, but compression set increases
Solution Approach 1:
The patent applies local quality by creating distinct matrix and domain regions with different properties. The matrix contains the conductive filler to provide conductivity, while the domains provide softness and low compression set. This spatial differentiation allows different regions to have different functions - the matrix handles conductivity while the domains handle mechanical softness, resolving the contradiction between conductivity and compression set.
Solution Approach 2:
The patent applies segmentation by dividing the elastomer into matrix and domain segments. The matrix segment contains conductive filler for conductivity, while the domain segment provides low compression set characteristics. This segmentation allows each segment to optimize its function independently, resolving the contradiction between conductivity and compression set stability.
3Reliability
If conductive filler is distributed uniformly throughout the elastomer, then conductivity is achieved, but hardness and compression set increase
Solution Approach 1:
The patent applies local quality by concentrating conductive filler in the matrix region rather than distributing it uniformly throughout the entire elastomer. This localized concentration of filler in the matrix allows conductivity to be achieved while the domain regions remain free of filler to maintain softness and low compression set, resolving the contradiction between conductivity and hardness.
Data Source
Figure 1
AI summary
The present invention provides a molded body which has low compression set and low hardness, while having electrical conductivity. This molded body contains a polyurethane elastomer and a conductive filler; the polyurethane elastomer comprises a matrix that contains a specific first structure and domains that are dispersed in the matrix; the domains each contain a second structure that is different from the first structure; the conductive filler is unevenly distributed in the matrix; the parameter A indicating the viscoelasticity term of the domains and the parameter B indicating the viscoelasticity term of the matrix as determined by a viscoelastic image of a cross-section of this molded body obtained by a scanning probe microscope satisfy the relational expression A < B; the content ratio of the conductive filler in this molded body is 0.02% by mass to 5.0% by mass; the volume resistivity of this molded body is 1.0 × 109 Ω·cm or less; and the Young's modulus of this molded body is 0.5 MPa to 4.0 MPa.