Functionalized Polymerization Initiator for Tire Tread Filler Affinity
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Solution Overview
Problem
Current functionalized polymers used in tire tread compositions face challenges in achieving optimal viscoelastic properties, particularly in improving the affinity of fillers like carbon black and silica, which affects rolling resistance and traction characteristics.
Innovation Solution
A functionalized polymerization initiator is developed, comprising the reaction product of an alkyl lithium compound and a specific compound, allowing for the synthesis of functionalized elastomers with improved filler affinity, achieved through a method involving the reaction of alkyl lithium with a compound of formula I, using organolithium compounds and specific monomers like 1,3-butadiene and styrene, and subsequent vulcanization processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If blends of various types of synthetic and natural rubber are utilized in tire treads to achieve inconsistent viscoelastic properties, then wet skid resistance is improved, but rolling resistance increases
Solution Approach 1:
The patent applies local quality by introducing functional groups at specific locations on the polymer chains (side chains or terminal positions) rather than uniformly throughout the entire polymer structure. This localized functionalization allows specific interaction sites for filler particles while maintaining the bulk polymer's viscoelastic properties, thereby improving filler affinity without compromising rolling resistance.
Solution Approach 2:
The patent creates composite materials by combining functionalized polymers with filler particles (carbon black, silica). The functional groups on the polymer chains form composite structures with the fillers, improving the interfacial interaction and filler dispersion, which enhances wet skid resistance without significantly increasing rolling resistance.
2Reliability
If functionalized polymers are synthesized to improve filler affinity, then rolling resistance and traction characteristics are improved, but polymerization process complexity increases
Solution Approach 1:
The patent applies preliminary action by incorporating functional groups into the initiator structure before polymerization begins. This pre-functionalization of the initiator ensures that the functional groups are automatically introduced at the polymer chain ends or side chains during the polymerization process itself, eliminating the need for separate post-polymerization functionalization steps and simplifying the overall process.
Solution Approach 2:
The patent uses the initiator as an intermediary that transfers functional groups to the growing polymer chains. The initiator acts as a mediator between the functional group source and the polymer backbone, enabling controlled introduction of functional groups at specific locations without requiring complex additional reagents or multi-step processes.
3Manufacturing precision
If metal initiators are used to produce stereo regulated polymers, then polymer microstructure control is improved, but filler affinity is reduced
Solution Approach 1:
The patent merges two previously separate functions into a single initiator structure: the metal center responsible for stereo-regulated polymerization and the functional groups responsible for filler affinity. By combining these functions in one initiator molecule, the patent achieves both stereo control and improved filler interaction simultaneously, resolving the contradiction between manufacturing precision and filler affinity.
Solution Approach 2:
The patent creates a multi-functional initiator that performs multiple roles: (1) initiating polymerization with stereo control through the metal center, (2) introducing functional groups for filler affinity, and (3) controlling polymer chain growth. This universal initiator structure eliminates the need for separate metal initiator and functionalization steps, achieving both stereo regulation and filler affinity.
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 solution enhances the viscoelastic properties of tire tread rubber compositions by improving the affinity of fillers, resulting in better rolling resistance and traction characteristics, as demonstrated by increased Mooney viscosity and specific viscoelastic and tensile properties in the rubber samples.
Implementation Method 1
The present invention is directed to a functionalized polymerization initiator, comprising the reaction product of an alkyl lithium compound and a compound of formula I
Implementation Method 2
In the living polymerization process based on active carbanionic center, metals from Groups I and II of the periodic table are commonly used to initiate the polymerization of monomers into polymers
Implementation Method 3
Functionalized rubbery polymers made by living polymerization techniques are typically compounded with sulfur, accelerators, antidegradants, a filler, such as carbon black, silica or starch, and other desired rubber chemicals and are then subsequently vulcanized or cured into the form of a useful article
Data Source
AI summary
The present invention is directed to a functionalized polymerization initiator of formula I where R1 and R2 are independently selected to be hydrogen or a C1 to C8 alkyl; R3, R4, and R5 are independently selected to be a C1 to C8 alkyl or C6 to C14 aryl or a structure of formula II where R6, R7 are independently selected to be a C1 to C8 alkyl or a C6 to C14 aryl. Also disclosed is a method of making a functionalized polymerization initiator and a method of making a functionalized elastomer. Further, a functionalized elastomer made by this method, a rubber composition comprising the functionalized elastomer and a pneumatic tire comprising the rubber composition is disclosed.