Aromatic Hydrocarbon Resin Rubber Mixture for Tire Sidewall Durability
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Solution Overview
Problem
Existing rubber mixtures for vehicle tires face a trade-off between rolling resistance and tear properties, with prior solutions either compromising on abrasion resistance or failing to optimize structural durability in the sidewall.
Innovation Solution
A sulfur-crosslinkable rubber mixture comprising 10 to 40 phr of natural polyisoprene, 60 to 90 phr of polybutadiene, 15 to 55 phr of fillers, and 25 to 100% aromatic hydrocarbon resin, which replaces plasticizers, enhancing tear resistance and maintaining or improving rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If liquid resin with softening point of -20 to +20°C is used to improve rolling resistance, then rolling resistance is reduced, but crack resistance and driving stability deteriorate
Solution Approach 1:
The patent changes the key parameter of resin softening point from the conventional -20 to +20°C range to a higher range of +40 to +130°C. This parameter change fundamentally alters the resin's behavior at operating temperatures, allowing it to provide rolling resistance benefits without the detrimental effects on crack resistance that occur with softer, lower-melting-point resins.
Solution Approach 2:
The patent uses a composite resin system combining aromatic monomers (25-75 wt%) and aliphatic monomers (25-75 wt%), creating a material with properties that neither component alone could provide. This composite approach allows the resin to achieve both low rolling resistance and high crack resistance through synergistic effects of the different monomer types.
2Loss of energy
If oil and hydrocarbon resin combination is used to improve rolling resistance indicators, then rolling resistance is partially improved, but tear properties and structural durability deteriorate
Solution Approach 1:
The patent extracts and eliminates the plasticizer component from conventional rubber compositions, replacing it entirely with the specific high-softening-point resin system. This removal of plasticizers, which are known to compromise tear resistance, while using the superior resin system, resolves the contradiction between rolling resistance and tear properties.
Solution Approach 2:
The patent changes the resin selection criteria by specifying a minimum softening point of +40°C (preferably +70 to +130°C), which fundamentally differentiates this composition from prior art using softer resins. This parameter change ensures the resin maintains structural integrity and tear resistance while still providing rolling resistance benefits.
3Reliability
If vegetable oil is used instead of aromatic oil to improve crack resistance, then crack resistance is improved, but rolling resistance deteriorates
Solution Approach 1:
The patent employs a composite resin system made from specific aromatic and aliphatic monomers in defined ratios. This composite material achieves both improved crack resistance and maintained rolling resistance, overcoming the trade-off observed when using vegetable oils alone which typically increase rolling resistance.
Solution Approach 2:
The patent changes from using vegetable oils (which have high rolling resistance) to a synthetic resin system with controlled softening point (+40 to +130°C). This parameter change in the plasticizing agent's thermal properties allows the composition to achieve crack resistance without the rolling resistance penalty associated with vegetable oils.
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 mixture achieves improved structural durability and tear resistance in vehicle tires while maintaining or improving rolling resistance, as demonstrated by enhanced fatigue and crack resistance, and reduced crack lengths over cycles.
Implementation Method 1
at least one hydrocarbon resin, which is made up of 25 to 100% by weight of aromatic monomers, and a softening point ASTM E 28 (ring and ball) from 70 to 130 °C, and 0 phr other plasticizers
Implementation Method 2
sulfur-crosslinkable rubber mixture
Data Source
AI summary
The invention relates to a sulfur-crosslinkable rubber mixture, in particular for the base of treads of the cap-base type of vehicle tires, and to a vehicle tire. Said rubber mixture contains: - at least one diene rubber and - 15 to 55 phr of at least one filler and - at least one hydrocarbon resin which is composed of 25 to 100% by weight of aromatic monomers, and has a softening point according to ASTM E 28 (ring and ball) of 70 to 130°C, and - 0 phr of further plasticizers, i.e. the sulfur-crosslinkable rubber mixture is free of further plasticizers.