Rubber Composition with Controlled Carbon Black Colloidal Properties
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Solution Overview
Problem
Current rubber compositions for tires face a trade-off between reducing heat build-up and maintaining mechanical properties such as tensile strength, wear resistance, and cut resistance, with existing methods either compromising on these properties or not providing sufficient improvements in heat build-up resistance.
Innovation Solution
A rubber composition that incorporates carbon black with specific colloidal characteristics, including a nitrogen adsorption specific surface area of 90 m2/g or less, a compressed DBP absorption of 95 to 120 mL/100 g, and a ratio of half-width to mode diameter in the Stokes diameter mass distribution curve of 0.65 or greater, which satisfies a specific formula, to maintain or enhance mechanical properties while reducing heat build-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the compounded amount of carbon black is reduced to reduce heat build-up, then heat build-up is reduced, but mechanical properties such as tensile strength and wear resistance are diminished
Solution Approach 1:
The patent applies parameter changes by precisely controlling the colloidal properties of carbon black, specifically the ratio of half-width to mode diameter in Stokes diameter mass distribution (0.65 or greater) and the relationship between N2SA and (24M4)/Dst. This allows using larger particle size carbon black with optimized distribution to reduce heat build-up while maintaining mechanical strength through the specific parameter ranges defined in the patent.
Solution Approach 2:
The patent employs composite materials by combining carbon black with specific colloidal characteristics with diene rubber in optimized proportions. The specific composite structure, defined by the relationship (24M4)/Dst ≥ 0.0093×N2SA - 0.06, creates a synergistic effect that simultaneously achieves low heat build-up and high mechanical properties.
2Temperature
If the particle size of carbon black is increased to reduce heat build-up, then heat build-up is reduced, but mechanical properties such as tensile strength and cut resistance are diminished
Solution Approach 1:
The patent applies parameter changes by optimizing the particle size distribution of carbon black, specifically setting the ratio of half-width to mode diameter in Stokes diameter mass distribution to 0.65 or greater. This controlled parameter change allows using larger particle size carbon black that reduces heat build-up while the specific distribution ratio maintains cut resistance and mechanical strength.
Solution Approach 2:
The patent applies local quality by creating a specific particle size distribution profile where the half-width to mode diameter ratio is 0.65 or greater. This local optimization of the size distribution profile ensures that while larger particles reduce heat build-up, the overall distribution maintains the mechanical properties needed for cut resistance.
3Temperature
If silica is blended in place of carbon black to reduce heat build-up, then heat build-up is reduced, but mechanical properties such as tensile strength and wear resistance are diminished
Solution Approach 1:
The patent applies parameter changes by precisely defining the colloidal characteristics of carbon black, including N2SA ≤ 90 m2/g and the specific relationship (24M4)/Dst ≥ 0.0093×N2SA - 0.06. These parameter changes enable the use of carbon black with optimized properties that simultaneously achieve low heat build-up and high wear resistance, avoiding the need to switch to silica which compromises mechanical properties.
4Strength
If conventional carbon black formulations are used to improve wear resistance, then wear resistance is improved, but heat build-up increases
Solution Approach 1:
The patent applies parameter changes by inverting the conventional approach: instead of accepting high heat build-up for wear resistance, it defines specific colloidal parameters of carbon black (N2SA ≤ 90 m2/g, (24M4)/Dst ≥ 0.0093×N2SA - 0.06, and half-width/mode diameter ratio ≥ 0.65) that simultaneously achieve both low heat build-up and high wear resistance, resolving the traditional trade-off.
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 rubber composition effectively reduces heat build-up while maintaining or enhancing tensile strength, wear resistance, and cut resistance, thereby improving steering stability, durability, and fuel economy performance.
Implementation Method 1
a nitrogen adsorption specific surface area N2SA of 90 m2/g or less
Implementation Method 2
a ratio ΔDst/Dst of a half width ΔDst (nm) of a mode diameter Dst to the mode diameter Dst (nm) in a Stokes diameter mass distribution curve of aggregates of the carbon black being 0.65 or greater
Data Source
AI summary
Provided is a rubber composition for tires containing, per 100 parts by mass of diene rubber, from 5 to 120 parts by mass of carbon black having a nitrogen adsorption specific surface area N2SA of 90 m2/g or less and a compressed DBP absorption (24M4) of 95 to 120 mL/100 g, a ratio ΔDst/Dst of a half width ΔDst (nm) of a mode diameter Dst to the mode diameter Dst (nm) in a Stokes diameter mass distribution curve of aggregates of the carbon black being 0.65 or greater, and the N2SA, (24M4), and Dst satisfying the following formula: (24M4)/Dst<0.0093×N2SA−0.06.