Tire Elastomer Composition for Interlayer Adhesion and Flexibility
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Solution Overview
Problem
Existing rubber compositions for tires face challenges in achieving good adhesion between different layers, particularly between the rolling strip and the summit frame, and between the flanks and the carcass frame, leading to decreased support properties and interface holding.
Innovation Solution
A rubber composition based on 20 to 100 PCE of ethylene copolymer, a first 1.3-diene such as 1,3-butadiene or isoprene, and a second 1.3-diene of formula (I), along with a plastic system, a reinforcing load, and a retication system, is developed to improve adhesion and support properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a tread composition is separated from the crown reinforcement by a tread sub-layer, then the tread can have specific properties for ground contact, but the adhesion between the tread and the crown reinforcement decreases
Solution Approach 1:
The patent applies the intermediary principle by introducing a specific copolymer composition as a bonding layer between the tread and crown reinforcement. This intermediary layer contains 70-90 mass% of a copolymer with highly saturated backbone and 10-30 mass% of a diene elastomer, creating chemical bridges that enhance adhesion while allowing the tread to maintain its specialized properties for ground contact
2Ease of operation
If sidewalls are arranged to cover the carcass reinforcement, then the sidewall provides protection and flexibility, but the adhesion between the sidewall and adjacent layers decreases
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the sidewall elastomer. Specifically, it uses a copolymer with a highly saturated backbone (fewer than 5 double bonds per 100 carbon atoms) combined with specific diene elastomers in controlled ratios, and adjusts the crosslinking density to optimize both flexibility and adhesion to adjacent layers
3Ease of manufacture
If conventional rubber compositions are used for different tire layers, then manufacturing is simplified, but the resistance to physical and chemical attacks decreases
Solution Approach 1:
The patent applies local quality by assigning different optimized compositions to different tire layers. Each layer (tread, sidewall, bonding layers) has a specifically tailored elastomer composition with controlled saturation levels, diene content, and crosslinking characteristics, allowing each region to have optimal resistance to the specific physical and chemical attacks it encounters
4Strength
If the copolymer has a highly saturated backbone with fewer than 5 double bonds per 100 carbon atoms, then adhesion to diene compositions improves, but the crosslinking density may be reduced
Solution Approach 1:
The patent applies composite materials by creating a multi-component elastomer system where a highly saturated copolymer backbone (providing adhesion) is combined with diene elastomers (providing crosslinking sites). The specific formulation includes 70-90 mass% copolymer and 10-30 mass% diene elastomer, creating a composite structure that achieves both strong adhesion to adjacent diene layers and sufficient crosslinking density for mechanical strength
Data Source
AI summary
The invention relates to a rubber composition based on: 20 to 100 phr of an ethylene copolymer, a first 1,3-diene which is 1,3-butadiene, isoprene or a mixture thereof and a second 1,3-diene of formula CH2=CR-CH=CH2, wherein the symbol R represents a hydrocarbon chain having 3 to 20 carbon atoms, wherein the ethylene units in the copolymer represent more than 50 mol % of the monomer units of the copolymer; 0 to 80 phr of at least one diene elastomer having a diene unit weight concentration greater than 50%; 10 to 100 phr of a plasticising system comprising at least one plasticising resin having a glass transition temperature of greater than 20°C and/or at least one liquid plasticiser at 23° C; a reinforcing filler; and a crosslinking system. The invention also relates to an elastomer laminate, and a rubber article, in particular a pneumatic or non-pneumatic tyre comprising this composition.