Block Diene Elastomer Hysteresis Reduction Segmentation
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Solution Overview
Problem
The tire industry faces challenges in reducing hysteresis in rubber compositions while maintaining their usability and processability, as existing solutions often lead to increased complexity in implementation.
Innovation Solution
A block diene elastomer with specific molecular mass ranges and functionalization, comprising polybutadiene blocks and diene elastomer blocks with a high molar rate of conjugated dienes, is used to form a crosslinkable rubber composition that reduces hysteresis while maintaining acceptable implementation for tire use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If functional initiators or functionalization agents are used to add interactive functions to polymer ends, then hysteresis is reduced, but implementation complexity increases
Solution Approach 1:
The patent segments the polymer structure into distinct blocks: polybutadiene blocks (A) and diene elastomer blocks (B) with interactive functions. This segmentation allows the interactive functions to be concentrated in specific blocks rather than distributed throughout the entire polymer chain, reducing overall implementation complexity while maintaining hysteresis reduction benefits
Solution Approach 2:
The patent applies local quality by placing interactive functions specifically in the diene elastomer blocks (B) rather than uniformly throughout the polymer. This localized approach allows the interactive functions to interact with reinforcing fillers where needed for hysteresis reduction, while the polybutadiene blocks maintain their elastomeric properties without unnecessary complexity
2Loss of energy
If interactive functions are added to reduce hysteresis, then energy loss is reduced, but processability deteriorates
Solution Approach 1:
By segmenting the polymer into polybutadiene blocks (A) and diene elastomer blocks (B), the patent ensures that not the entire polymer chain contains interactive functions. The polybutadiene blocks provide good processability and elastomeric behavior, while the diene blocks contribute hysteresis reduction, achieving a balance between energy loss reduction and ease of manufacture
Solution Approach 2:
The patent controls the molecular mass parameters (Mn1 for polybutadiene blocks: 2,500-20,000 g/mol; Mn2 for diene elastomer blocks: 80,000-350,000 g/mol) and the ratio Mn1/Mn2 (5-20%) to optimize both hysteresis reduction and processability. These parameter changes ensure the polymer has appropriate viscosity and handling characteristics while maintaining the desired energy loss reduction
3Loss of energy
If block copolymer with specific molecular mass ranges is used, then hysteresis reduction is optimized, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific molecular mass ranges for each block type (Mn1: 2,500-20,000 g/mol for polybutadiene, Mn2: 80,000-350,000 g/mol for diene elastomer) rather than requiring exact values. This segmented approach with ranges provides manufacturing flexibility while still achieving optimized hysteresis reduction
Solution Approach 2:
The patent specifies the ratio Mn1/Mn2 should be between 5 and 20%, which provides a target parameter for manufacturing control. This ratio parameter is easier to control during synthesis than absolute molecular masses, as it allows adjustment of one block's mass relative to the other, reducing the stringency of manufacturing precision requirements
Data Source
AI summary
The invention relates to a block diene elastomer having the following formula: (I) where: n and m are each integers greater than or equal to 0, such that n+m=1 and n+m =20; each block A consists of a polybutadiene; each block B consists of a diene elastomer, the molar level of units derived from conjugate dienes of which is greater than 15%, the blocks B being identical to one another; X is an organic or inorganic group, which can contain a function interacting with a reinforcing filler; the number-average molecular weight Mn1 of each Block A varies from 2500 to 20,000 g/mol; the number-average molecular weight Mn2 of each block B varies from 80,000 to 350,000 g/mol; and the chaining rate 1,2 in each block A is comprised between 1 and 20%.