Polyacrylate Crosslinking via Cyclic Ether Catalyst System
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Solution Overview
Problem
Current thermal crosslinking methods for polyacrylate hotmelts face challenges such as short processing time, inhomogeneous coating, and limited crosslinking depth due to rapid reaction rates, especially when using isocyanates or radiation-induced processes, which can lead to product defects like streaky patterns and reduced cohesion.
Innovation Solution
A crosslinker-accelerator system containing cyclic ethers like epoxy or oxetane groups, combined with accelerators like dicyandiamides and melamines, allows for controlled thermal crosslinking at reduced temperatures, enabling longer processing times and homogeneous coating without the need for actinic radiation or high heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If thermal crosslinking is performed using conventional crosslinkers like isocyanates or radiation-induced processes, then crosslinking speed is improved, but processing time becomes too short and coating homogeneity deteriorates
Solution Approach 1:
The patent introduces a catalyst as an intermediary substance that mediates the crosslinking reaction between the crosslinker and polyacrylate. The catalyst accelerates the reaction rate, enabling fast crosslinking without requiring excessively short processing times, thus resolving the contradiction between crosslinking speed and processing time.
Solution Approach 2:
The patent changes the reaction parameters by using specific catalysts and controlling temperature conditions. This allows the crosslinking reaction to proceed at optimized rates that maintain both sufficient crosslinking speed and adequate processing time for homogeneous coating.
2Length of stationary object
If thermal crosslinking is performed using conventional methods, then crosslinking depth is improved, but coating homogeneity deteriorates due to rapid reaction rates
Solution Approach 1:
The catalyst acts as a mediator that distributes the crosslinking reaction uniformly throughout the coating layer. This enables deep crosslinking penetration while maintaining reaction uniformity, thus achieving both crosslinking depth and coating homogeneity simultaneously.
Solution Approach 2:
The patent employs controlled thermal processing that allows the crosslinking reaction to progress uniformly through the coating layer over time, ensuring homogeneous crosslinking even at significant depths from the surface.
3Speed
If high temperatures are used for thermal crosslinking, then crosslinking speed is improved, but energy consumption increases and environmental impact worsens
Solution Approach 1:
The patent changes the temperature parameter by using catalysts that enable crosslinking to proceed at reduced temperatures. This maintains sufficient crosslinking speed while significantly reducing energy consumption and environmental impact compared to conventional high-temperature methods.
Solution Approach 2:
The patent replaces thermal energy input with catalytic chemical action to drive the crosslinking reaction. This substitution of thermal-mechanical energy with chemical catalysis reduces energy consumption while maintaining crosslinking effectiveness.
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 system provides stable, controlled crosslinking with increased processing time, ensuring uniform and bubble-free coatings, even after cooling to room temperature, with enhanced crosslinking speed and reduced environmental impact compared to prior methods.
Implementation Method 1
thermal crosslinking of polyacrylates with functional groups that are suitable for entering into linking reactions with cyclic ethers, in particular epoxy or oxetane groups
Implementation Method 2
meltable polyacrylate masses (other names: 'polyacrylate hot melts', 'acrylate hot melts')
Data Source
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AI summary
Crosslinker-accelerator system for the thermal crosslinking of polyacrylates with functional groups suitable for undergoing crosslinking reactions with cyclic ethers, in particular epoxide or oxetane groups, comprising at least one epoxide or oxetane group-containing substance (crosslinker) and at least one accelerating substance (accelerator) for the crosslinking reaction at a temperature below the melting temperature of the polyacrylate.