Polyisocyanate Mixture for Low-Viscosity Solvent-Free Coatings
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Solution Overview
Problem
There is a need for sustainable polyisocyanate mixtures with low viscosity to enable solvent-free or low-solvent processing, particularly for thick-film coatings in the construction sector, as bio-based polyisocyanates like PDI exhibit higher viscosities and require larger amounts of organic solvents, which is undesirable for environmentally friendly coatings.
Innovation Solution
A polyisocyanate mixture comprising polyisocyanate M) and polyisocyanate N) in specific weight ratios, where M) is a PDI allophanate with a defined structure and N) has uretdione, isocyanurate, allophanate, biuret, or oxadiazinetrione structures, formulated to achieve low viscosity and improved elasticity, allowing for solvent-free or low-solvent application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If bio-based PDI polyisocyanates are used to produce sustainable coatings, then sustainability is improved, but viscosity increases and solvent-free processing becomes difficult
Solution Approach 1:
The patent combines PDI polyisocyanate with HDI polyisocyanate in a mixture to achieve low viscosity while maintaining sustainability. The HDI component contributes to lowering the overall viscosity of the mixture, enabling solvent-free processing while the PDI component provides the sustainable, bio-based characteristic.
Solution Approach 2:
The patent changes the compositional parameters by formulating a specific weight ratio range (40:60 to 90:10 of PDI to HDI) to optimize the balance between sustainability and viscosity. This parameter adjustment allows the mixture to achieve sufficiently low viscosity for solvent-free processing while retaining the sustainable properties of bio-based PDI.
2Object-generated harmful factors
If PDI polyisocyanates are used in solvent-free form, then environmental friendliness is improved, but processing becomes difficult due to high viscosity
Solution Approach 1:
The patent merges PDI polyisocyanate with HDI polyisocyanate to create a mixture that processes easily in solvent-free form. The HDI component acts as a viscosity modifier that enables smooth application and processing while the PDI component maintains the environmentally friendly, sustainable characteristic of the coating system.
Solution Approach 2:
The patent adjusts the compositional parameters within the weight ratio range of 40:60 to 90:10 (PDI:HDI) to optimize processing ease. This parameter change ensures the mixture achieves sufficiently low viscosity for practical solvent-free application methods while preserving the high environmental friendliness of bio-based formulations.
3Quantity of substance
If higher PDI content is used to improve sustainability, then bio-based content increases, but viscosity increases and solvent-free processing is compromised
Solution Approach 1:
The patent defines a specific weight ratio range (40:60 to 90:10 of PDI to HDI) that allows optimization of bio-based content while controlling viscosity. Within this range, formulations can achieve high PDI content (up to 90%) for maximum sustainability while still maintaining sufficiently low viscosity for solvent-free processing, or balance both properties at intermediate ratios.
Solution Approach 2:
The patent creates a universal polyisocyanate mixture formulation that can serve multiple functions: it provides sustainable bio-based content, maintains low viscosity for solvent-free processing, and delivers improved elasticity in the final coating. The mixture composition can be adjusted within the specified range to prioritize different properties as needed.
Data Source
AI summary
The invention relates to a polyisocyanate mixture, a process for its preparation, and the use of the polyisocyanate mixture. The invention further relates to a composition containing the polyisocyanate mixture, a process for producing a coating on a substrate, and the coated substrate.