Multifunctional Polycarbodiimide Crosslinker Viscosity Control
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Solution Overview
Problem
Existing methods for preparing multifunctional polycarbodiimides as crosslinking agents require high amounts of solvent, leading to high viscosity and low concentrations of reactive groups, making them inefficient and environmentally undesirable, and resulting in poor dispersibility in water-based systems.
Innovation Solution
A process involving the reaction of mono- and polyisocyanates with a carbodiimide catalyst, followed by chain extension with hydrophilic and amine/hydroxyl functional compounds, and the use of plasticizers and surface active components to reduce solvent usage and enhance dispersibility in water, while maintaining effective crosslinking capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If high amounts of solvent are used in the preparation method, then the viscosity becomes manageable during the first stage of preparation, but the crosslinking agent contains a relatively large amount of volatile organic compounds which is environmentally undesirable
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific functional groups (carboxylic acid functions, hydroxyl functions, amine functions) that enable the system to achieve desired viscosity characteristics without relying on large amounts of volatile organic solvents. This transforms the preparation approach from solvent-dependent to functionally-dependent viscosity control.
Solution Approach 2:
The invention discards the need for high amounts of volatile organic solvents by using alternative functional groups that provide the necessary rheological control. The process recovers from the traditional solvent-based approach to a more environmentally friendly functional-group-based approach that eliminates harmful volatile organic compounds while maintaining processability.
2Ease of operation
If high amounts of solvent are used in the preparation method, then the polycarbodiimide can be prepared with manageable viscosity, but the concentration of carbodiimide groups and the concentration of the other reactive groups are relatively low
Solution Approach 1:
The patent changes the compositional parameters by incorporating multiple reactive functional groups (carboxylic acid, hydroxyl, amine) that allow the system to achieve optimal viscosity without solvent dilution. This parameter change enables higher concentrations of carbodiimide groups and other reactive groups to coexist with manageable viscosity through functional group interactions rather than solvent mediation.
Solution Approach 2:
The invention creates a composite functional structure where carboxylic acid functions, hydroxyl functions, and amine functions work together in a synergistic manner. This composite approach to molecular functionality allows the polycarbodiimide to exhibit appropriate flow characteristics while maintaining high concentrations of reactive groups, eliminating the need for solvent-based viscosity control.
3Ease of manufacture
If conventional methods are used to prepare multifunctional polycarbodiimides, then the crosslinking agent can be synthesized, but it requires a relatively high amount of multifunctional polycarbodiimide crosslinking agent to obtain a good crosslinking degree
Solution Approach 1:
The patent applies multi-functionality by incorporating carboxylic acid functions, hydroxyl functions, and amine functions within the same polycarbodiimide molecule. This universal design allows a single crosslinking agent to participate in multiple crosslinking reactions simultaneously, increasing its effectiveness and reducing the total amount needed to achieve a good crosslinking degree compared to conventional single-function crosslinking agents.
Solution Approach 2:
The invention creates a composite functional architecture where multiple reactive groups (carboxylic acid, hydroxyl, amine) are integrated into the polycarbodiimide structure. This composite approach enables one crosslinking agent molecule to form multiple crosslinking points, thereby reducing the quantity required to achieve effective crosslinking of the polymer while maintaining ease of manufacture.
4Ease of manufacture
If existing methods are used, then multifunctional polycarbodiimides can be prepared, but they show poor dispersibility in water or aqueous systems
Solution Approach 1:
The patent changes the chemical parameter composition by incorporating hydrophilic functional groups (carboxylic acid functions, hydroxyl functions, amine functions) that enhance water affinity. This parameter change transforms the polycarbodiimide from a water-repellent structure to one that is compatible with water-based systems, improving dispersibility while maintaining the preparation methodology.
Solution Approach 2:
The invention applies local quality by introducing specific hydrophilic functional groups at strategic positions within the polycarbodiimide molecule. These localized hydrophilic regions (carboxylic acid, hydroxyl, and amine groups) create water-compatible zones that enable dispersibility in aqueous systems without compromising the overall crosslinking functionality of the molecule.
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 process significantly reduces solvent usage, lowers viscosity, and increases the concentration of reactive groups, allowing for efficient crosslinking and easy dispersion in water-based systems, improving the overall performance and environmental sustainability of the crosslinking agents.
Implementation Method 1
the reaction of a mono- and/or polyisocyanate at 80-180° C. in the presence of 0.05-5 weight percentage of a carbodiimide catalyst, in which a polycarbodiimide or an isocyanate functional polycarbodiimide is formed
Implementation Method 2
the compound containing a hydrophilic group and one or multiple amine and/or hydroxyl functions... easy dispersion in water-based systems
Data Source
AI summary
A process for the preparation of multifunctional polycarbodiimides, which are used as crosslinking agents, in which the polycarbodiimide is prepared by reacting mono- and polyisocyanates in the presence of a mono- or polyisocyanate that contains one or multiple additional reactive functional groups and in the presence of a carbodiimide catalyst, and thereafter terminating or chain extending the polycarbodiimide chain. Between 0 and 10% of an organic solvent and/or between 0 and 30% of a plasticizer and/or between 0 and 30% of a surface active component is added to the product during, before or after the polycarbodiimide forming reaction and/or the capping reaction and/or the chain extending reaction. Further, the invention relates to a coating mixture in which the polycarbodiimide is used as crosslinking agent and to the cured material obtained with the coating mixture.