Isocyanate Composition Low Viscosity Water Dispersibility
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Solution Overview
Problem
Existing polyisocyanate compositions face issues with high viscosity leading to poor water dispersibility, drying properties, and water resistance of coating films, along with stability problems in aqueous dispersion.
Innovation Solution
A polyisocyanate composition with a specific isocyanate compound of general formula (I) that includes a hydrophilic compound, maintaining an average number of isocyanate groups to ensure low viscosity and excellent water dispersibility, drying properties, and wet-adhesion resistance, while controlling the molecular weight and using a hydrophilic compound to improve hydrolysis resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the number of isocyanate groups is decreased to reduce viscosity, then the viscosity decreases and organic solvent usage reduces, but the drying properties deteriorate
Solution Approach 1:
The patent changes the chemical structure parameters of the polyisocyanate by introducing specific cyclic carbamate structures and controlling the average number of isocyanate groups to 2.0-3.0, achieving low viscosity while maintaining adequate drying properties through optimized molecular architecture rather than simply reducing isocyanate content
Solution Approach 2:
The patent creates a composite polyisocyanate structure containing multiple functional groups including cyclic carbamate groups, isocyanate groups, and hydrophilic groups within the same molecular framework, achieving synergistic effects that simultaneously provide low viscosity, good water dispersibility, and adequate drying properties
2Adaptability or versatility
If polyisocyanate is dispersed in water by introducing nonionic hydrophilic groups, then water dispersibility improves, but the water-resistance of the coating film deteriorates
Solution Approach 1:
The patent introduces hydrophilic groups at specific locations within the polyisocyanate molecular structure (local modification) rather than uniformly throughout, allowing the molecule to maintain hydrophobic character in the main chain for water-resistance while having localized hydrophilic regions for water dispersibility
Solution Approach 2:
The patent carefully controls the average number of hydrophilic groups to 0.1-0.5 per molecule, optimizing the balance between water dispersibility and water-resistance by precise quantitative control of hydrophilic group content
3Object-generated harmful factors
If the viscosity of polyisocyanate is decreased to reduce organic solvent usage, then environmental protection improves, but the stability of aqueous dispersion deteriorates
Solution Approach 1:
The patent optimizes the molecular weight and structural parameters of the polyisocyanate to achieve low viscosity intramolecularly through molecular design, eliminating the need for organic solvents while maintaining adequate viscosity for stable aqueous dispersion formation
Solution Approach 2:
The patent uses water as an intermediary medium to disperse the polyisocyanate, replacing organic solvents by creating water-dispersible polyisocyanate compositions through molecular structure modification that enables stable aqueous dispersion without organic solvent assistance
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
The composition achieves low viscosity, enhanced water dispersibility, improved drying and wet-adhesion resistance, and maintains the integrity of the coating film's physical properties, including weather resistance and external appearance.
Implementation Method 1
introducing a nonionic hydrophilic group into a polyisocyanate makes it possible to disperse the polyisocyanate in water
Data Source
AI summary
An isocyanate composition having a low viscosity, a water dispersibility, a drying property, and a water-resistance contains an isocyanate compound of general formula (I). In the general formula (I), A represents a residual group containing a reactant structure of an active hydrogen-containing hydrophilic compound and an isocyanate group, the sum (m+n) of the average number m and the average number n is 3, provided that m is an integer of 1 or more. R represents a group of general formula (II).