SET-LRP Block Copolymers for Hot-Melt Adhesives
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Solution Overview
Problem
Existing methods for forming block copolymers, such as ATRP and RAFT, often result in polymers with dark coloration and high reaction temperatures, which are undesirable for applications like labels, tapes, and UV curable adhesives, and fail to produce polymers with narrow molecular weight distribution and UV crosslinking functionality.
Innovation Solution
The process involves single electron transfer living radical polymerization (SET-LRP) using a solid copper catalyst, allowing for the formation of block copolymers with narrow polydispersity and low color, conducted at lower temperatures, and incorporating a photoinitiator for UV curable crosslinking, specifically targeting the synthesis of di and tri-block copolymers for hot-melt adhesive systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ATRP or RAFT procedures are used to create block copolymers, then the polydispersity is lower and copolymer size can be tailored, but the polymers formed tend to be dark or colored
Solution Approach 1:
The patent changes the chemical parameters of the polymerization system by using SET-LRP with copper wire/copper mesh and specific ligands (Me6TREN, PMDETA) instead of traditional ATRP or RAFT catalysts. This parameter change results in polymers with low coloration while maintaining control over molecular weight and polydispersity, directly resolving the contradiction between manufacturing precision and harmful coloration.
2Ease of manufacture
If ATRP or RAFT procedures are used, then block copolymers can be created, but the required reaction temperatures are quite high
Solution Approach 1:
The patent changes the thermal parameters by employing SET-LRP conditions with copper wire/copper mesh catalysts and specific ligands that enable polymerization at lower temperatures compared to traditional ATRP or RAFT methods. This allows block copolymer formation while reducing the harmful effect of high reaction temperatures.
3Device complexity
If traditional free radical polymerization is used, then the process is simple, but it cannot create block copolymers with controlled structure
Solution Approach 1:
The patent introduces copper wire/copper mesh as an intermediary catalyst system that mediates between the simplicity of free radical polymerization and the precision of controlled radical polymerization. The copper catalyst system enables block copolymer formation with controlled structure while maintaining relatively simple processing conditions through SET-LRP mechanism.
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 achieves block copolymers with narrow molecular weight distribution, low color, and UV crosslinking functionality, suitable for hot-melt adhesives, by maintaining low polydispersity and enabling efficient UV curable properties at lower temperatures.
Implementation Method 1
single electron transfer living radical polymerization (SET-LRP)
Implementation Method 2
incorporating a photoinitiator for UV curable crosslinking
Data Source
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AI summary
Disclosed is a method for formation of block copolymers using a Single Electron Transfer Living Radical Polymerization (SET-LRP) process. The process can be used to form di and tri-block copolymers from vinyl monomers. In one embodiment the SET-LRP process comprises initially forming a macroinitiator using SET-LRP to form a first block of a di or tri-block copolymer and then using SET-LRP to form additional blocks of the copolymer. The produced block copolymers have very narrow polydispersity indexes and controlled molecular weights. The process permits incorporation of photoinitiators in any of the block formation reactions. The method also includes purification processes that result in a block copolymer having very low color making it useful in a variety of applications. In one application block copolymers prepared according to the present process can be used in hot-melt adhesives.