Diblock Copolymer Synthesis for Thermoplastic Polyurethane Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hard phase modified thermoplastic polyurethanes (HMP-TPU) face issues with randomly distributed urethane hard phases disrupting crystallization behavior and stability, leading to lower heat stability, propensity for dissolution, and irreversible cleavage reactions, which affect their mechanical and chemical properties.
Innovation Solution
A process involving the reaction of aromatic polyester with a polymer diol at elevated temperatures, followed by reaction with diisocyanate in excess molar amounts, to form diblock copolymers without a urethane hard phase, ensuring clear phase separation and improved stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diol is reacted with isocyanate in known production processes, then thermoplastic polyurethanes are formed, but randomly distributed urethane hard phase disrupts crystallization behavior and stability
Solution Approach 1:
The patent applies segmentation by creating distinct diblock copolymer structures with separate hard phases (polyester blocks) and soft phases (polyol blocks) rather than allowing random distribution of urethane bonds. This is achieved by reacting polyester with diol to form diblock copolymers where the hard phase segments are clearly defined and separated, preventing disruption of crystallization behavior while maintaining soft phase stability.
Solution Approach 2:
The patent implements local quality by creating regions with different properties: the hard phases (polyester blocks) provide crystallinity and structural stability, while the soft phases (polyol blocks) provide elasticity and flexibility. This localized differentiation ensures that each phase performs its specific function without interfering with the other, resolving the contradiction between stability and crystallization behavior.
2Strength
If urethane hard phase is formed in soft phase, then polymer structure is created, but heat stability decreases and irreversible cleavage reactions occur
Solution Approach 1:
The patent extracts the urethane hard phase formation from the soft phase by using a different chemical approach: instead of forming urethane bonds within the soft phase, the patent forms diblock copolymers where hard phases are created through polyester-diol reactions. This removes the harmful urethane bonds from the soft phase environment, preventing heat-induced cleavage reactions while still providing the necessary polymer structure through the diblock architecture.
Solution Approach 2:
The patent changes the chemical parameters of the polymer formation process by using specific molar ratios of diisocyanate to alcohol groups (at least 0.9:1) and controlling reaction conditions to favor diblock copolymer formation over random urethane hard phase formation. This parameter control ensures high heat stability by preventing the formation of thermally labile urethane bonds in the soft phase while maintaining adequate polymer structure.
3Manufacturing precision
If diisocyanate is employed in excess molar amount, then diblock copolymer formation is enhanced, but phase separation clarity must be maintained
Solution Approach 1:
The patent employs feedback control by monitoring and controlling the diisocyanate to alcohol molar ratio (maintaining at least 0.9:1) to optimize diblock copolymer formation while preventing excessive crosslinking that would compromise phase separation. This controlled excess ensures adequate reaction completion and diblock structure formation while maintaining the clarity of phase separation through precise stoichiometric control.
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 resulting diblock copolymers exhibit enhanced low and high-temperature properties, improved hydrolysis resistance, and extended cycle times with improved mechanical properties such as tensile strength and abrasion resistance.
Implementation Method 1
reaction of at least one aromatic polyester having a melting point in the range from 160° C. to 350° C. and at least one polymer diol having a melting point of less than 100° C. at a temperature of greater than 200° C. to obtain a mixture (G-a)
Implementation Method 2
reaction of the mixture (G-a) with at least one diisocyanate, wherein the diisocyanate is employed in a molar amount of at least 0.9 based on the alcohol groups of the polymer diols
Implementation Method 3
clear phase separation and the high crystallinity hard phase result in very short cycle times
Data Source
AI summary
The present invention relates to a process for producing a diblock copolymer comprising the reaction of at least one aromatic polyester having a melting point in the range from 160° C. to 350° C. and at least one polymer diol having a melting point of less than 100° C. at a temperature of greater than 200° C. to obtain a mixture (G-a); and the reaction of the mixture (G-a) with at least one diisocyanate, wherein the diisocyanate is employed in a molar amount of at least 0.9 based on the alcohol groups of the polymer diols. The present invention further relates to diblock copolymers obtained or obtainable according to such a process and to the use of such diblock copolymers for producing extruded, injection molded and pressed articles and also foams, cable sheaths, hoses, profiles, drive belts, fibers, nonwovens, films, moldings, plugs, housings, damping elements for the electricals industry, automotive industry, mechanical engineering, 3-D printing, medicine and consumer goods.