Carbon Black Aggregate Size Distribution for Tire Performance
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Solution Overview
Problem
Conventional methods to improve tire abrasion resistance increase rolling resistance, and vice versa, creating an antagonistic relationship between the two properties, while existing proposals focus on aggregate size distribution of carbon black measured by centrifugal sedimentation methods, which are inadequate for detecting larger aggregates that can degrade rubber.
Innovation Solution
Employing a light scattering method using an ultraviolet ray to measure the aggregate size distribution of carbon black, specifying the standard deviation and other parameters to improve both abrasion resistance and rolling resistance without impairing rubber composition processability, by adjusting the 24M4DBP absorbed amount, CTAB specific surface area, and aggregate size distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the specific surface area of carbon black is increased to improve abrasion resistance, then the abrasion resistance is improved, but the rolling resistance increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the aggregate size distribution of carbon black, specifically setting the ratio ΔD50/Dst between 0.50-0.80 and standard deviation σ between 25-45 nm. This optimization of size distribution parameters allows the carbon black to provide adequate abrasion resistance while minimizing rolling resistance, resolving the contradiction between these two properties.
2Strength
If the structure of carbon black is increased to improve abrasion resistance, then the abrasion resistance is improved, but the viscosity of unvulcanized rubber increases deteriorating processability
Solution Approach 1:
The patent resolves this contradiction by optimizing the aggregate size distribution parameters, specifically controlling the standard deviation σ to be 25-45 nm and the ratio ΔD50/Dst to be 0.50-0.80. These parameter optimizations ensure that the carbon black provides sufficient structural reinforcement for abrasion resistance while maintaining appropriate viscosity levels for good processability of unvulcanized rubber.
3Loss of energy
If the specific surface area of carbon black is decreased to reduce rolling resistance, then the rolling resistance is decreased, but the abrasion resistance deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the aggregate size distribution rather than simply reducing specific surface area. By controlling the ratio ΔD50/Dst to be 0.50-0.80 and standard deviation σ to be 25-45 nm, the patent achieves low rolling resistance while maintaining adequate abrasion resistance through the optimized size distribution profile.
4Measurement precision
If conventional centrifugal sedimentation method is used to measure aggregate size distribution, then the measurement is conventional, but it is inadequate for detecting larger aggregates that can degrade rubber
Solution Approach 1:
The patent replaces the conventional centrifugal sedimentation method with laser diffraction measurement. This substitution enables more accurate detection of aggregate size distribution, including larger aggregates that centrifugal sedimentation cannot adequately detect. The laser diffraction method provides superior measurement precision and reliability for characterizing carbon black aggregates in the context of rubber degradation.
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 solution effectively enhances both abrasion resistance and low rolling resistance of tires without compromising the processability of the rubber composition, as demonstrated by the improved indices in the examples compared to comparative examples.
Implementation Method 1
newly employing a light scattering method as a measurement means of the aggregate size distribution of carbon black
Implementation Method 2
a laser source emitting a ultraviolet ray used in the present invention
Data Source
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AI summary
The present invention provides carbon black, the standard deviation σ of aggregate size distribution of which is obtained by a light scattering method using an ultraviolet ray, the standard deviation σ satisfying the expression (1) : σ< -48.7 × (24M4DBP/Dst) + 161.8 (1). In the expression (1), 24M4DBP represents the dibutyl phthalate absorption number (cm3/100 g) of compressed sample, and Dst (nm) is a Stokes' equivalent diameter providing the mode in aggregate size distribution obtained by a centrifugal sedimentation method. The carbon black can improve both the abrasion resistance and the low rolling resistance of a tire. The present invention also provides a rubber composition mixed with this carbon black, and a pneumatic tire including a tread part formed by using this rubber composition.