Pneumatic Tire Tread Using Hydroxyl-Functionalized Polybutadiene
Solution Overview
Problem
Tires face a challenge in balancing good rolling resistance and wet traction characteristics, as improvements in one property often lead to a reduction in the other, due to the viscoelastic inconsistencies of rubber compounds used in tire treads.
Innovation Solution
A pneumatic tire tread composition incorporating a diene elastomer, silica, blocked mercaptosilane, a resin as traction resin, and a relatively low molecular weight polybutadiene functionalized with a hydroxyl group, which includes a blend of styrene-butadiene rubber and natural or synthetic polyisoprene, optimized with alkoxysilane and sulfur-containing functional groups to enhance hysteresis loss characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rubbers with high rebound are used to reduce rolling resistance and improve treadwear, then wear characteristics improve, but wet skid resistance decreases
Solution Approach 1:
The patent utilizes a composite rubber composition comprising multiple rubber types (natural rubber, styrene-butadiene rubber, polybutadiene rubber) combined with silica filler and specific additives. This composite approach allows the tread to exhibit both high rebound for wear resistance and appropriate hysteresis for wet skid resistance, resolving the contradiction between these two properties.
Solution Approach 2:
The patent specifies precise parameter ranges for the rubber compounds, including rebound values (70-85%), silica content (20-40 parts per 100 parts rubber), and molecular weight ranges for polybutadiene (1,000-50,000 g/mol). By optimizing these parameters, the composition achieves both improved treadwear and maintained wet skid resistance.
2Object-affected harmful factors
If rubbers with large energy loss are used to increase wet skid resistance, then wet traction improves, but rolling resistance increases
Solution Approach 1:
The patent carefully controls the hysteresis loss parameters by selecting polybutadiene with specific molecular weights (1,000-50,000 g/mol) and limiting its content to 5-20 parts per 100 parts rubber. This parameter optimization ensures sufficient energy dissipation for wet skid resistance while minimizing excessive rolling resistance.
Solution Approach 2:
The patent applies different rubber compounds with specific properties to different regions of the tread. The composition includes rubbers with tailored rebound and hysteresis characteristics positioned to optimize both wet traction and rolling resistance performance in their respective functional zones.
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 tire composition achieves a compromise between low rolling resistance and improved wet traction, demonstrating enhanced performance in both aspects compared to traditional rubber compounds.
Implementation Method 1
These properties depend, to a great extent, on the dynamic viscoelastic properties of the rubbers utilized in making the tire
Implementation Method 2
a relatively low molecular weight polybutadiene functionalized with a hydroxyl functional group... optimized with alkoxysilane and sulfur-containing functional groups to enhance hysteresis loss characteristics
Implementation Method 3
a blocked mercaptosilane... optimized with alkoxysilane and sulfur-containing functional groups
Data Source
AI summary
Disclosed is a pneumatic tire having a tread, the tread comprising a rubber composition comprising a diene elastomer, silica, a blocked mercaptosilane, a resin, and a polybutadiene functionalized with a hydroxyl functional group. The polybutadiene has a weight average molecular weight (Mw) in a range of from 1000 to 25000 g/gmol.