Simultaneous Polymerization of Liquid and Functionalized Polymers
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Solution Overview
Problem
The processing and handling of liquid polymers in tire tread rubber compositions are inefficient due to difficulties in isolating them from hydrocarbon solvents, and many functional initiators used to impart functional end groups have stability and solubility issues in these solvents, necessitating additional steps and reducing processing efficiency.
Innovation Solution
A method involving the anionic initiation of living polymers with functional initiators, such as dithianes or trialkyltin hydrides, to form polymers with functional end groups, allowing for the polymerization of both liquid and high molecular weight polymers in a single reactor, thereby simplifying the synthesis and eliminating the need for separate desolventization and blending steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If liquid polymer is isolated from hydrocarbon solvent by conventional methods such as coagulation, then the liquid polymer can be obtained, but the isolation is difficult due to low molecular weight and requires additional blending steps
Solution Approach 1:
The patent combines the polymerization of liquid polymer and high molecular weight polymer into a single simultaneous process in one reactor. The living polymer chains are formed concurrently with functional initiator incorporation, eliminating the need for separate isolation, desolventization, and blending steps that were previously required.
Solution Approach 2:
The patent performs preliminary functional initiator incorporation during the living polymerization process itself, before the polymerization is complete. This allows the functional groups to be installed on the polymer chains while they are still active and soluble, facilitating easier subsequent processing and eliminating separate functionalization steps.
2Reliability
If functional initiators are used to impart functional end groups on polymer chains, then the hysteresis is reduced and rolling resistance is improved, but the initiators have stability and solubility issues in hydrocarbon solvents
Solution Approach 1:
The patent changes the chemical parameters of the functional initiators by selecting specific compounds (dithianes and trialkyltin hydrides) that have appropriate solubility and stability characteristics in hydrocarbon solvents. This allows the functional initiators to remain stable and soluble during the polymerization process while still effectively imparting functional end groups on the polymer chains.
3Manufacturing precision
If liquid polymer and high molecular weight polymer are polymerized separately and then blended, then both polymers can be obtained with desired properties, but processing efficiency is decreased due to additional steps
Solution Approach 1:
The patent merges the separate polymerization processes for liquid polymer and high molecular weight polymer into a single simultaneous polymerization reaction. Both types of polymer chains are formed concurrently in the same reactor under controlled conditions, maintaining manufacturing precision while eliminating multiple processing steps.
Solution Approach 2:
The patent creates a universal polymerization system that can simultaneously produce both liquid polymer and high molecular weight polymer with functional end groups in one process. The system is designed to handle multiple polymer types and molecular weights concurrently, providing multi-functionality that eliminates the need for separate processing lines.
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
This method enhances processing efficiency by allowing the simultaneous polymerization of liquid and high molecular weight polymers with functional end groups, improving the microstructure uniformity and reducing heat buildup in rubber compositions, while also stabilizing the initiators and improving solubility.
Implementation Method 1
forming a living polymer, wherein said living polymer is anionically initiated and comprises a cation
Implementation Method 2
adding a functional initiator precursor of the formula FI-H, wherein H is hydrogen and FI is a functional group, said H terminates said living polymer and said FI and said cation form a functional initiator
Implementation Method 3
adding monomer, wherein said functional initiator initiates anionic polymerization of said monomer
Data Source
AI summary
ABSTRACT [0054] A method comprising: (a) forming a living liquid polymer, wherein said living liquid polymer is anionically initiated and comprises a cation; (b) adding a functional initiator precursor of the formula FI-H, wherein H is hydrogen and FI is a functional group, said H terminates said living liquid polymer resulting in said liquid polymer having a number average molecular weight of about 20,000 (g/mole) to about 100,000 (g/mole), and said FI and said cation form a functional initiator; (c) adding monomer, wherein said functional initiator initiates anionic polymerization of said monomer; and (d) terminating the polymerization reaction initiated in step (c). Steps (a) through (c) may be conducted in a single reactor, allowing a liquid polymer to be dispersed in a functionalized polymer in a single polymerization step. Thus, the liquid polymer does not have to be handled separately and processing efficiency is improved.