Halogenated Isoolefin Elastomer Processability
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Solution Overview
Problem
Halogenated isoolefin elastomers used in tire innerliners face challenges with processability, particularly with carbon black fillers, where high filler loadings lead to poor stress relaxation, affecting handling and performance in tire manufacturing.
Innovation Solution
Developing halogenated isoolefin elastomers with specific Mooney viscosity, molecular weight, and branching index characteristics, such as brominated isobutylene-methylstyrene (BIMSM) elastomers, which exhibit similar stress relaxation properties to conventional bromobutyl rubbers when filled with carbon black, improving melt properties and processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high filler loadings of carbon black are used in halogenated isoolefin elastomers, then reinforcing characteristics and air barrier performance are improved, but stress relaxation becomes slow and processability deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the elastomer by introducing halogenated isoolefin units with specific molecular structures and compositions. This modifies the polymer's interaction with carbon black filler, enabling fast stress relaxation even at high filler loadings while maintaining air barrier performance.
Solution Approach 2:
The patent creates a composite material system combining halogenated isoolefin elastomer with carbon black filler. The specific chemical composition of the elastomer ensures optimal filler dispersion and interaction, achieving both high reinforcing characteristics and fast stress relaxation for improved processability.
2Strength
If high filler loadings of carbon black are used in halogenated isoolefin elastomers, then reinforcing characteristics are improved, but stress relaxation becomes slow and processability deteriorates
Solution Approach 1:
The patent modifies the molecular parameters of the elastomer by incorporating halogenated isoolefin units with specific structures. This changes how the polymer interacts with carbon black, maintaining strong reinforcing characteristics while enabling fast stress relaxation for better processability.
Solution Approach 2:
The patent develops a composite system where halogenated isoolefin elastomer combines with carbon black filler. The specific chemical composition optimizes filler-polymer interaction, achieving high strength with fast stress relaxation that improves manufacturing processability.
3Reliability
If conventional bromobutyl rubbers are used in tire innerliners, then air retention is good, but processability with carbon black fillers is poor due to slow stress relaxation
Solution Approach 1:
The patent changes the chemical composition parameters by introducing halogenated isoolefin units with specific molecular structures. This modifies the polymer's stress relaxation behavior while preserving air retention properties, enabling both good air barrier performance and improved processability.
Solution Approach 2:
The patent creates an improved composite material system combining halogenated isoolefin elastomer with carbon black. The specific chemical composition ensures optimal filler interaction that maintains air retention while achieving fast stress relaxation for better processability.
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 BIMSM elastomers provide enhanced processability and physical properties comparable to conventional elastomers, including improved air barrier performance, making them suitable for tire innerliners and innertubes with reduced air permeability and increased durability.
Implementation Method 1
the uncured composition has a fast stress relaxation when strained to a prescribed deformation
Implementation Method 2
improved air barrier performance, making them suitable for tire innerliners and innertubes with reduced air permeability
Data Source
AI summary
The present invention provides an elastomeric composition processable in a curable, filled rubber formulation. The composition comprises a halogenated interpolymer of a C4 to C7 isoolefin and from 3 to 20 weight percent alkylstyrene and comprising from 0.2 to 2 mole percent haloalkylstyrene, a Mooney viscosity less than 37, a number average molecular weight less than 270,000, a weight average molecular weight less than 470,000, a z-average molecular weight less than 700,000, and a branching index (g′) from 0.4 to 1.1. Also disclosed are a method of making a cured, filled rubber article, comprising compounding the elastomeric composition with filler and curative, processing the compounded composition to form a shape of the article, and curing the composition to obtain the article in the formed shape, as well as a tire comprising an innerliner made by the method.