Modified Thermoplastic Resins With Reduced Oligomers for Tire Tread Balance
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Solution Overview
Problem
Current thermoplastic resin technologies face challenges in achieving a high glass transition temperature (Tg) while maintaining low z-average molecular weight (Mz) to effectively modify elastomer compounds for improved tire tread performance, balancing wet grip and rolling resistance, and ensuring compatibility with rubber matrices.
Innovation Solution
Modified thermoplastic resins with reduced oligomer content, specifically dimer, trimer, and pentamer species, are developed to increase the Tg to Mz ratio, achieved through selective removal of low molecular weight species, allowing for enhanced viscoelastic properties and compatibility with elastomers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the molecular weight of thermoplastic resin is increased to raise glass transition temperature (Tg), then Tg is improved, but z-average molecular weight (Mz) increases reducing compatibility with elastomers
Solution Approach 1:
The patent segments the molecular weight distribution by selectively removing the oligomer fraction (molecular weight < 600 g/mol) through fractionation processes. This creates a modified thermoplastic resin with a narrowed molecular weight distribution where the remaining polymer chains have higher average molecular weight and improved Tg, while eliminating the incompatible low molecular weight species that would otherwise limit the maximum achievable Tg.
Solution Approach 2:
The patent changes the molecular weight distribution parameters by removing the oligomer fraction, thereby increasing the number average molecular weight (Mn) and z-average molecular weight (Mz) in a controlled manner. This parameter change increases Tg while maintaining compatibility because the removal of oligomers shifts the entire distribution toward higher molecular weights without creating excessive polydispersity.
2Temperature
If oligomer content is reduced to increase Tg/Mz ratio, then Tg/Mz ratio is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary fractionation during the thermoplastic resin production process to remove oligomers before the resin is used in rubber compounding. This preliminary action eliminates the need for complex post-processing or specialized handling equipment, as the oligomer removal is integrated into the standard resin manufacturing workflow using established fractionation techniques.
Solution Approach 2:
The patent uses gel permeation chromatography (GPC) as an analytical copying method to characterize and control the molecular weight distribution. By measuring and monitoring the oligomer fraction through GPC, manufacturers can quality control the Tg/Mz ratio without requiring complex real-time process control systems, as the GPC analysis provides a straightforward fingerprint of the molecular weight distribution.
3Temperature
If high molecular weight thermoplastic resin is used to increase Tg, then Tg is improved, but compatibility with rubber matrix deteriorates
Solution Approach 1:
The patent applies local quality by creating a thermoplastic resin with a narrowed molecular weight distribution that has uniform properties throughout. By removing the oligomer fraction and concentrating on a specific molecular weight range, the resin achieves consistent Tg and compatibility characteristics, allowing it to uniformly interact with the rubber matrix without the heterogeneity that would arise from using broad distribution high molecular weight resins.
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2
AI summary
Modified thermoplastic hydrocarbon thermoplastic resins are provided, as well as methods of their manufacture and uses thereof in rubber compositions. The modified thermoplastic resins are modified by decreasing the relative quantity of the dimer, trimer, tetramer, and pentamer oligomers as compared to the corresponding unmodified thermoplastic resin polymers, resulting in a product that exhibits a greater shift in the glass transition temperature of the elastomer(s) used in tire formulations. This translates to better viscoelastic predictors of tire tread performance, such as wet grip and rolling resistance. The modified thermoplastic resins impart remarkable properties on various rubber compositions, such as tires, belts, hoses, brakes, and the like. Automobile tires incorporating the modified thermoplastic resins are shown to possess excellent results in balancing the properties of rolling resistance, tire wear, snow performance, and wet braking performance.