Conductive Additive for Silica-Filled Rubber
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Solution Overview
Problem
Silica-filled rubber compositions face challenges in achieving electrical conductivity while maintaining or improving physical and mechanical properties, as silica particles have low affinity for non-polar rubbers and carbon nanotubes tend to agglomerate, leading to dispersion issues and inadequate conductivity.
Innovation Solution
A conductive additive comprising 1-20 wt% carbon nanotubes, 20-90 wt% organosilane composition, and 5-70 wt% organic rubber, which synergistically enhances electrical conductivity and mechanical properties by ensuring uniform dispersion and coupling of silica and carbon nanotubes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon nanotubes are added to silica-filled rubber composition to improve electrical conductivity, then electrical conductivity increases, but dispersion difficulty increases due to strong bundling tendency of carbon nanotubes
Solution Approach 1:
The patent uses organosilane coupling agent as an intermediary substance between silica particles and carbon nanotubes. The organosilane modifies the surface of silica particles, creating a compatibility layer that prevents carbon nanotube bundling and promotes uniform dispersion throughout the rubber matrix, thereby resolving the dispersion difficulty while maintaining electrical conductivity
Solution Approach 2:
The patent changes the surface chemistry parameters of silica particles by introducing organosilane modifiers. This parameter change alters the interfacial properties between filler particles and carbon nanotubes, reducing aggregation and improving dispersion quality without compromising the electrical conductive network
2Strength
If silica particles are used as primary filler to improve mechanical properties and adhesion, then mechanical strength and adhesion increase, but electrical conductivity decreases as rubber becomes dielectric
Solution Approach 1:
The patent creates a composite filler system combining silica particles with carbon nanotubes. The silica provides mechanical reinforcement and adhesion, while the carbon nanotubes form a conductive network. The synergistic combination of these two materials with different functions resolves the contradiction between mechanical strength and electrical conductivity
Solution Approach 2:
The carbon nanotube additive serves multiple functions simultaneously: it provides electrical conductivity, acts as a dispersing agent for silica particles, and reinforces the rubber matrix. This multi-functionality allows a single additive to address both the conductivity deficiency and mechanical property enhancement needs
3Stability of the object's composition
If organosilane coupling agent is used to improve dispersion of silica particles, then dispersion quality improves, but processing complexity increases due to additional mixing stages
Solution Approach 1:
The patent combines the organosilane coupling agent with carbon nanotubes into a single integrated additive package. This merging of functions allows the dispersing and conductive properties to be achieved simultaneously in one mixing stage, eliminating the need for separate organosilane treatment steps and reducing processing complexity
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 additive significantly reduces electrical volume resistivity and improves mechanical properties such as tensile strength, tear resistance, and dynamic characteristics, while simplifying the mixing process and maintaining material uniformity.
Implementation Method 1
carbon nanotubes, which tend to form strong bundles, is a technical challenge... However, the dispersion of nanocarbon fillers... makes it possible to achieve a small size of carbon nanotube agglomerates... The additive significantly reduces electrical volume resistivity
Implementation Method 2
The surface of silica particles is highly saturated with polar silanol (SiOH) and siloxane (SiOSi) groups... organosilane composition (S)... synergistically enhances electrical conductivity and mechanical properties by ensuring uniform dispersion and coupling of silica and carbon nanotubes
Implementation Method 3
However, the dispersion of nanocarbon fillers, especially single-walled and double-walled carbon nanotubes, which tend to form strong bundles, is a technical challenge... The additive significantly reduces electrical volume resistivity... dissipation of the static electricity charge
Data Source
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AI summary
The invention provides an additive to silica-filled rubber composition comprising 1-20 wt % carbon nanotubes, 20-90 wt % of organosilane composition (S), and 5-70 wt % of organic rubber (R) soluble in organosilane composition (S). The technical result of the provided disclosure is decreasing electrical volume resistivity and simultaneously improving physical-mechanical properties of rubber, including elastic moduli, tear strength and others. A further important technical result of the provided disclosure is simplicity of the rubber mixing process and the possibility of industrial application of the provided methods in the standard technologies by substitution of a liquid organosilane coupling agent by a viscous paste-like additive provided by this invention. The invention provides also the method to produce the additive.