Reversible Sorbed Catalyst Bed for Polyurethane Viscosity Control
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Solution Overview
Problem
Conventional 2K PUR systems face the challenge of paint viscosity increasing rapidly due to catalyst presence, leading to unusable paint when operations are stopped, as the curing reaction commences upon mixing, necessitating immediate use or disposal.
Innovation Solution
A process using a catalyst bed with a catalyst reversibly sorbed on a substrate, allowing the catalyst to be released into the reaction mixture only when needed, enabling the reaction to be accelerated and then paused, thus maintaining paint usability by controlling viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a catalyst is added to accelerate the curing reaction, then the drying time is reduced, but the viscosity increases rapidly causing paint to become unusable when operations are stopped
Solution Approach 1:
The catalyst system transitions from a static, continuously active state to a dynamic, controllable state. The patent employs a catalyst that can be activated and deactivated on demand, allowing the reaction rate to be adjusted dynamically. This enables the system to provide rapid curing when needed while maintaining paint stability during storage or pauses in operation, resolving the contradiction between fast drying and operational flexibility.
Solution Approach 2:
The catalyst is applied in periodic bursts rather than continuously. The patent describes adding catalyst in controlled amounts at specific intervals or conditions, allowing the reaction to proceed rapidly during application periods while pausing between additions. This periodic catalysis maintains paint usability during storage while achieving rapid drying during active operation.
2Productivity
If the curing reaction is accelerated to improve processing efficiency, then productivity increases, but paint must be disposed of when processing is interrupted
Solution Approach 1:
The patent prepares the paint mixture in advance without adding catalyst, keeping it stable and usable for extended periods. The catalyst is added only at the point of application or in controlled increments, allowing the paint to be prepared beforehand without premature reaction. This preliminary preparation without catalyst activation prevents waste while maintaining the ability to process efficiently when ready.
Solution Approach 2:
The system changes the catalytic activity parameter dynamically. By controlling the presence, concentration, or activation state of the catalyst, the reaction rate can be adjusted between very slow (for storage) and very fast (for processing). This parameter control allows the same paint formulation to serve both long-term storage and rapid processing needs, eliminating disposal requirements.
3Ease of manufacture
If a heterogeneous catalyst is used to enable easy separation, then the catalyst can be removed from the reaction mixture, but the concept cannot be applied to polyurethane systems that react over prolonged periods
Solution Approach 1:
The patent introduces a soluble catalyst that acts as an intermediary between the reactants. Rather than using a heterogeneous catalyst that must be physically separated, the soluble catalyst remains in the reaction mixture throughout the extended reaction period, continuously facilitating the curing process. This intermediary approach allows prolonged reaction times while maintaining catalytic activity without requiring removal or separation steps.
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 approach allows for the storage of paint without catalyst, enabling it to be used later, maintaining workability and preventing unnecessary paint disposal, while ensuring efficient processing and drying times.
Implementation Method 1
the catalyst bed contains a catalyst reversibly sorbed on a substrate
Implementation Method 2
the catalyst catalyses the reaction of isocyanate groups with themselves or with Zerewitinoff-active compounds
Data Source
AI summary
A process for preparing a polyurethane polymer comprises the step of:I) mixing a first component (100) comprising a polyisocyanate with a second reactant component (200) comprising a compound having Zerewitinoff-active hydrogen atoms in a mixing vessel (300) to obtain a reaction mixture (400),wherein the first reactant component (100) and/or the second reactant component (200) are contacted with a catalyst bed (500) before they are mixed in the mixing vessel (300) and/or the reaction mixture (400) is contacted with a catalyst bed (500), wherein the catalyst bed (500) contains a catalyst reversibly sorbed on a substrate, the catalyst catalyses the reaction of isocyanate groups with themselves or with Zerewitinoff-active compounds and the catalyst is released into the first component (100), second component (200) or reaction mixture (400) that is in contact with the catalyst bed (500), such that a reaction mixture (410) containing the catalyst is obtained.