Rubber Composition Using Thermoplastic Resin for Wet Braking
Solution Overview
Problem
Existing rubber compositions for tire treads face challenges in providing high braking performance on both dry and wet road surfaces, particularly on slippery surfaces like manhole covers, due to compatibility issues with aroma oils and insufficient braking performance on icy and snowy roads.
Innovation Solution
A rubber composition is developed using a combination of natural rubber (70% or more) compounded with specific thermoplastic resins (5-50 parts by mass) and silica (20-120 parts by mass), which improves glass transition temperature, loss tangent, and flexibility, enhancing braking performance on dry and wet surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aroma oil is compounded with rubber components (NR and BR) to improve wet road surface performance, then wet road surface performance is improved, but rolling resistance increases and compatibility is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters by replacing aroma oil with C5-based resins and adjusting the rubber component ratios (NR ≥30%, BR ≥10%, SBR 5-30%). This parameter change resolves the contradiction by achieving wet road performance through resin-based mechanisms rather than aroma oil, while controlling rolling resistance through optimized compound formulation.
Solution Approach 2:
The patent uses a composite material system combining multiple rubber components (NR, BR, SBR) with C5-based resins and silica filler. This composite approach allows synergistic effects where the resin-rubber-silica combination improves wet road adhesion through polar interactions and surface properties, while the overall formulation maintains acceptable rolling resistance characteristics.
2Ease of operation
If natural rubber content is increased to 70 mass % or more to improve flexibility and braking performance, then flexibility and braking performance are improved, but glass transition temperature decreases
Solution Approach 1:
The patent sets natural rubber content at 70 mass% or more to ensure flexibility and braking performance, while compensating for the low glass transition temperature effect by using C5-based resins that interact with the rubber matrix. The resins and silica filler create a reinforced structure that maintains operational flexibility across a broader temperature range despite the high NR content.
Solution Approach 2:
The patent creates a composite system where high natural rubber content (≥70%) provides flexibility and braking performance, while C5-based resins and silica filler form a reinforcing network. This composite structure allows the NR-dominated matrix to maintain flexibility while the resin-rubber-silica interactions provide structural integrity and temperature resistance.
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 achieves high braking performance on dry and wet surfaces, including slippery ones, by increasing the glass transition temperature and flexibility, while maintaining low rolling resistance and improved follow-up ability on low-friction surfaces.
Implementation Method 1
A rubber composition, when compounded with the thermoplastic resin (B) selected from among C5-based resins, C5- to C9-based resins, C9-based resins, terpene-based resins, terpene-aromatic compound-based resins, rosin-based resins, dicyclopentadiene resins, and alkylphenol-based resins, can be raised in glass transition temperature (Tg), improved in loss tangent (tan δ) at 0° C., and improved in tire performance on a wet road surface.
Implementation Method 2
the filler (C) contains silica by 50 mass % to 100 mass %. Silica is dispersed in the rubber component having the thermoplastic resin (B) fully dispersed therein, which allows for more flexible deformation of the rubber, with the result that the rubber is improved in follow-up ability on a road surface that is low in friction coefficient.
Implementation Method 3
The rubber component itself has high flexibility with the content of natural rubber being 70 mass % or more, and thus exhibits high braking performance on a dry road surface and on a slippery wet road surface such as a manhole surface.
Data Source
AI summary
Provided is a rubber composition that allows for manufacturing a tread rubber that is high in braking performance on a dry surface road and also high in braking performance even on a wet road surface such as a manhole surface that is slipperier than an asphalt road surface. The rubber composition is prepared by compounding a rubber component (A) including a natural rubber by 70 mass % or more, and by further compounding, with the rubber component as 100 parts by mass: (B) at least one kind of thermoplastic resins selected from among C5-based resins, C5- to C9-based resins, C9-based resins, terpene-based resins, terpene-aromatic compound-based resins, rosin-based resins, dicyclopentadiene resins, and alkylphenol-based resins, at 5 parts by mass to 50 parts by mass; and (C) a filler including silica, at 20 parts by mass to 120 parts by mass, in which the filler (C) contains silica by 50 mass % to 100 mass %.