Silane-Functional Ethylene-Diene Copolymers for Lower Tire Rubber Stiffness
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Solution Overview
Problem
Existing ethylene/1,3-butadiene copolymers used in tire rubber compositions exhibit high stiffness, making them unsuitable for certain applications.
Innovation Solution
A copolymer of ethylene and 1,3-diene with a silanol or alkoxysilane function, produced using a specific catalytic system and functionalizing agent, to reduce stiffness and improve interaction with reinforcing fillers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If copolymers of ethylene and 1,3-butadiene are used in rubber compositions for tyres, then the rubber composition exhibits higher stiffness, but this makes it unsuitable for certain applications where lower stiffness is required
Solution Approach 1:
The patent changes the chemical parameters of the copolymer by introducing silanol or alkoxysilane functional groups through reaction with compounds of formula (IV). This chemical modification transforms the physical properties of the copolymer, specifically reducing its stiffness while maintaining its elastomeric characteristics, thereby making it suitable for applications requiring lower stiffness.
Solution Approach 2:
The patent creates a composite material system by combining the ethylene/1,3-diene copolymer with silanol/alkoxysilane functional groups and reinforcing inorganic fillers. The functional groups enhance the interaction between the polymer matrix and the inorganic filler, creating a composite material with tailored mechanical properties including reduced stiffness and improved versatility for tyre applications.
2Strength
If copolymers of ethylene and 1,3-butadiene are synthesized using rare-earth metallocene catalytic system, then the copolymer exhibits higher stiffness, but the cured stiffness becomes too high for certain applications
Solution Approach 1:
The patent applies parameter changes by chemically modifying the copolymer structure synthesized via rare-earth metallocene catalysis. The introduction of silanol or alkoxysilane functional groups through reaction with compounds of formula (IV) fundamentally alters the physical properties of the cured copolymer, reducing its stiffness to levels suitable for various tyre applications while preserving the benefits of the catalytic synthesis method.
3Strength
If silanol or alkoxysilane functional groups are introduced to the copolymer, then the interaction with reinforcing fillers is improved, but the synthesis process becomes more complex
Solution Approach 1:
The patent applies preliminary action by incorporating the functionalization step into the polymerization process itself. The copolymer is synthesized with reactive end groups that can subsequently react with compounds of formula (IV) to introduce silanol or alkoxysilane functional groups. This approach integrates the functionalization requirement into the base synthesis, reducing overall process complexity compared to separate functionalization steps.
Solution Approach 2:
The patent uses compounds of formula (IV) as intermediaries to introduce silanol or alkoxysilane functional groups to the copolymer. These intermediary compounds facilitate the transfer of functional groups from small molecule precursors to the polymer chain, enabling improved filler interaction without requiring direct incorporation of complex functional groups during polymerization.
4Strength
If the copolymer is functionalized to reduce stiffness, then the mechanical properties are improved, but the manufacturing process requires additional steps
Solution Approach 1:
The patent applies preliminary action by preparing the copolymer with reactive end groups during the polymerization step, which are then used to introduce silanol or alkoxysilane functional groups in a subsequent controlled reaction. This two-stage approach allows the base polymer to be synthesized first, followed by functionalization only to the extent needed, optimizing the balance between improved mechanical properties and manufacturing simplicity.
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 copolymer achieves lower stiffness and improved mechanical properties, enhancing the performance of rubber compositions in tires.
Implementation Method 1
the copolymerization of ethylene and of a 1,3-diene of formula (I) in the presence of a catalytic system comprising a metallocene of formula (II) and an organomagnesium compound of formula (III)
Implementation Method 2
copolymerization of ethylene and 1,3-diene in the presence of a catalytic system comprising a rare-earth metallocene
Implementation Method 3
c) where appropriate, a hydrolysis reaction
Data Source
AI summary
A copolymer of ethylene and of a 1,3-diene of formula CH2═CR—CH═CH2, which copolymer bears a silanol or alkoxysilane function, the symbol R representing a hydrocarbon chain having from 3 to 20 carbon atoms, is provided. Such a copolymer improves the compromise between the content of ethylene in the polymer, its crystallinity and the stiffness of a rubber composition containing it.