Low Catalyst Polyisoprene Rubber Durability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional synthetic rubber lacks durability compared to natural rubber, particularly under high severity conditions, due to main-chain breaks and gelation issues during polymerization, which reduces its breaking resistance, abrasion resistance, and crack growth resistance.
Innovation Solution
A polymer with a residual catalyst amount of 300 ppm or less, specifically a synthesized polyisoprene or isoprene copolymer, is used to form a network structure during vulcanization, enhancing durability by maintaining strain-induced crystallinity and processability, with a number average molecular weight of 1.5 million or more and a preferred molecular weight distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cis content of synthetic polyisoprene is increased to improve strain-induced crystallinity, then durability is improved, but the polymer still shows main-chain breaks and gelation under high severity conditions
Solution Approach 1:
The patent changes the chemical composition parameters by introducing a specific cyclic ether group-containing monomer (30-70 mass%) into the polyisoprene structure. This compositional parameter change prevents main-chain breaks and gelation while maintaining high cis-1,4 content (90-99%) for strain-induced crystallinity, thereby improving durability without compromising stability under high severity conditions.
2Strength
If high-molecular weight polymer is synthesized to improve durability, then breaking resistance is enhanced, but chain ends may be denatured with tin tetrachloride or titanium tetrachloride causing gelation
Solution Approach 1:
The patent extracts and eliminates the harmful denaturation effect caused by tin tetrachloride or titanium tetrachloride at chain ends. By incorporating a cyclic ether group-containing monomer that specifically prevents this denaturation, the patent removes the gelation problem while maintaining high molecular weight (Mn ≥ 1.5 million) for improved breaking resistance.
3Ease of manufacture
If synthetic rubber is used to reduce cost and availability issues, then manufacturing is improved, but durability is reduced compared to natural rubber
Solution Approach 1:
The patent creates a composite polymer structure combining polyisoprene backbone with cyclic ether group-containing monomer units. This composite structure synthesizes rubber with properties superior to natural rubber, achieving Mn ≥ 1.5 million, gel fraction ≤ 10%, and enhanced durability while maintaining synthetic rubber manufacturing advantages of cost-effectiveness and availability.
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 polymer composition significantly improves the crosslinked rubber's breaking resistance, abrasion resistance, and crack growth resistance, surpassing conventional synthetic rubber's durability while maintaining processability.
Implementation Method 1
a residual catalyst remaining in a polymer (at least one of a synthesized polyisoprene and an isoprene copolymer) by a certain reduced amount is less likely to inhibit crosslinking reaction of the polymer during vulcanization
Implementation Method 2
the cis content of synthetic polyisoprene is conventionally increased to improve strain-induced crystallinity
Data Source
AI summary
Provided are: a polymer capable of providing a crosslinked rubber composition with improved durability (i.e., breaking resistance, abrasion resistance, and crack growth resistance) and a method for producing the same, a rubber composition containing the polymer, a crosslinked rubber composition obtained by crosslinking the rubber composition, and a tire having the crosslinked rubber composition. The polymer is either a synthesized polyisoprene or an isoprene copolymer, and contains a residual catalyst in an amount of 300 ppm or less.