Conductive Resin Composition for Uniform Dispersion
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Solution Overview
Problem
Conductive thermoplastic resin compositions face issues with mechanical property degradation and conductivity variations due to excessive use of fillers like carbon black, and non-uniform dispersion of carbon nanotubes, especially in complex-shaped products and thin sheets, leading to sloughing phenomena and surface defects.
Innovation Solution
A conductive resin composition comprising 10-40 wt% of a first copolymer, 30-60 wt% of a second copolymer, 10-20 wt% of a third styrene-butadiene copolymer, 1-10 wt% of conductive fillers such as carbon nanotubes, and 5-10 wt% of a rubber component, along with metal salts and silicone oil, which are mixed and processed to create a masterbatch for uniform dispersion and enhanced moldability and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If excessive amount of carbon black is used to provide desired conductivity, then conductivity is improved, but mechanical properties particularly impact resistance are significantly degraded
Solution Approach 1:
The patent changes the particle size parameter of carbon black from conventional large particles to fine particles of 0.1 to 1 μm. This parameter change allows achieving desired conductivity with reduced filler content, thereby maintaining impact resistance. The fine particles create more efficient conductive networks at lower concentrations
Solution Approach 2:
The patent creates a composite material system combining thermoplastic resin with fine carbon black particles and a rubber component. This composite structure allows the carbon black to provide conductivity while the rubber component maintains mechanical properties, resolving the contradiction between conductivity and impact resistance
2Reliability
If excessive amount of carbon black is used, then conductivity is improved, but unnecessary particles remain on sheet surface after molding, degrading surface characteristics
Solution Approach 1:
The patent changes the particle size parameter to 0.1 to 1 μm, which is small enough to be fully embedded in the resin matrix during molding. This prevents particle protrusion on the sheet surface while maintaining conductivity, eliminating the need for excessive filler content
3Reliability
If carbon nanotubes are dispersed in resin composition, then conductivity is provided, but carbon nanotubes are not uniformly dispersed in bent portion requiring higher elongation, degrading conductivity at bent portion
Solution Approach 1:
The patent changes the particle size parameter to 0.1 to 1 μm, which provides optimal balance between dispersion uniformity and conductivity. These fine particles disperse more uniformly in the resin matrix, especially in bent portions requiring elongation, maintaining conductivity throughout the molded product
Solution Approach 2:
The patent ensures uniform distribution of conductive filler throughout the entire resin composition, including bent portions. The fine particle size enables consistent local conductivity even in regions experiencing deformation during molding
4Adaptability or versatility
If thermoplastic resin is molded into complex shapes, then adaptability is improved, but sloughing phenomenon occurs due to desorption of conductive filler
Solution Approach 1:
The patent changes the particle size parameter to 0.1 to 1 μm, which prevents filler desorption during molding. These fine particles remain firmly embedded in the resin matrix even when molded into complex shapes with bending and elongation, preventing sloughing and maintaining conductivity stability
Solution Approach 2:
The patent incorporates a rubber component in the resin composition that prevents filler desorption before molding occurs. This preventive measure ensures that conductive filler remains firmly embedded during subsequent molding into complex shapes, avoiding sloughing phenomenon
Data Source
AI summary
Provided are a conductive resin composition which includes 10 to 40 wt% of a first copolymer having an average particle size of 1 to 5 µm; 30 to 60 wt% of a second copolymer having an average particle size of 0.1 to 1 µm; 10 to 20 wt% of a third copolymer prepared by copolymerizing styrene and butadiene in a weight ratio of 60 to 80 : 20 to 40; 1 to 10 wt% of a conductive filler; and 5 to 10 wt% of a rubber component, and a method of preparing the same.