Polyimide Belt Boron Nitride Nanotubes Thermal Conductivity
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Solution Overview
Problem
Current polyimide fuser belts in electrophotographic printing have limitations in thermal conductivity and Young's modulus due to the anisotropic nature of boron nitride powders, which reduces their effectiveness despite efforts to enhance thermal conductivity with metal and ceramic fillers, and there is a need for materials that meet rigid specifications while reducing manufacturing costs.
Innovation Solution
An endless belt comprising a polyimide substrate layer with dispersed boron nitride nanotubes, which have a specific surface area and concentration, along with optional intermediate and release layers, to improve thermal conductivity and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If boron nitride powder is incorporated into polyimide to improve thermal conductivity, then thermal conductivity increases, but the concentration required is very high (above 20%) due to anisotropic conduction
Solution Approach 1:
The patent changes the physical form of boron nitride from powder to nanotubes, which fundamentally alters the thermal conduction characteristics. This parameter change enables efficient thermal conductivity improvement at much lower concentrations (0.1-10 wt%) compared to powder formulations requiring above 20% concentration, directly resolving the contradiction between achieving high thermal conductivity and minimizing filler concentration.
Solution Approach 2:
The patent creates a composite material system using boron nitride nanotubes dispersed in polyimide matrix. This composite approach leverages the superior isotropic thermal conduction properties of nanotube structures while maintaining the mechanical integrity of the polyimide base material, achieving effective thermal management with minimal filler content.
2Temperature
If metal and ceramic fillers are incorporated into polymeric materials to enhance conductivity, then thermal conductivity improves, but the Young's modulus of the polymeric material decreases
Solution Approach 1:
The patent changes the filler morphology from conventional metal/c ceramic particles to boron nitride nanotubes with specific aspect ratios and crystalline structures. This parameter change enables the filler to provide thermal conduction pathways without acting as stress concentration points that would reduce the Young's modulus, thus improving thermal conductivity while preserving mechanical strength.
Solution Approach 2:
The patent develops a composite material using boron nitride nanotubes in polyimide matrix, where the nanotube geometry and material properties are specifically selected to provide thermal conduction enhancement while maintaining or improving the mechanical properties of the base polymer, avoiding the strength degradation associated with traditional metal and ceramic fillers.
3Temperature
If boron nitride powder is used to improve thermal conductivity in polyimide, then some thermal conductivity enhancement occurs, but the effect is not significant due to anisotropic character requiring very high concentration
Solution Approach 1:
The patent changes the boron nitride morphology from powder to nanotubes, which fundamentally improves the efficiency of thermal conduction. This parameter change reduces the required concentration from above 20% to 0.1-10 wt%, significantly reducing material costs and improving manufacturing economics while achieving superior thermal conductivity enhancement.
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 use of boron nitride nanotubes in the polyimide substrate layer enhances thermal diffusivity and Young's modulus, providing improved thermal conductivity and mechanical strength while potentially reducing manufacturing costs.
Implementation Method 1
the boron nitride nanotubes having a surface area of from 50 m2/g to 200 m2/g and an average length-to-diameter aspect ratio of from 100:1 to 1000:1. The endless belt may further comprise an intermediate layer disposed on the substrate layer, the intermediate layer comprising a material selected from the group consisting of silicones, fluorosilicones and fluoroelastomers
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
An endless belt comprising a polyimide-based substrate layer. A plurality of boron nitride nanotubes are dispersed in the polyimide.