Low-Viscosity Polyisocyanate Composition with Controlled Crosslinking
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Solution Overview
Problem
Existing polyisocyanate compositions with urethodione groups face challenges in achieving low viscosity while maintaining high crosslinkability and storage stability, often producing diisocyanate monomers during storage, which limits their use.
Innovation Solution
A polyisocyanate composition derived from an aliphatic diisocyanate monomer and a monoalcohol, with specific ratios of isocyanurate trimer, allophanate groups, urethodione dimer, and viscosity, that does not produce diisocyanate monomers during storage, achieved through controlled isocyanuration, allophanation, and urethodionation reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If polyisocyanate having an urethodione group is used to decrease viscosity, then viscosity is reduced, but crosslinkability becomes low and storage stability deteriorates due to diisocyanate monomer formation
Solution Approach 1:
The patent creates a composite polyisocyanate composition containing multiple components: polyisocyanate with urethodione groups (for low viscosity), polyisocyanate with isocyanurate groups (for high crosslinkability), and polyisocyanate with allophanate groups (for storage stability). This composite approach allows simultaneous achievement of low viscosity, high crosslinkability, and excellent storage stability by combining the advantages of different polyisocyanate structures.
Solution Approach 2:
The patent precisely controls the concentration parameters of different polyisocyanate components: urethodione group-containing polyisocyanate at 5-30 mass%, isocyanurate group-containing polyisocyanate at 70-95 mass%, and allophanate group-containing polyisocyanate at 1-30 mass%. By optimizing these parameter ranges, the invention achieves the balance between viscosity reduction and maintenance of crosslinkability and storage stability.
2Reliability
If polyisocyanate having an isocyanurate group is produced to maintain crosslinkability, then crosslinkability is maintained, but viscosity increases and storage stability worsens due to diisocyanate monomer formation
Solution Approach 1:
The patent combines isocyanurate group-containing polyisocyanate (for crosslinkability) with urethodione group-containing polyisocyanate (for low viscosity) and allophanate group-containing polyisocyanate (for storage stability). This composite structure maintains high crosslinkability while the urethodione component ensures low viscosity and the allophanate component prevents diisocyanate monomer formation during storage.
Solution Approach 2:
The patent assigns different functional roles to different components within the polyisocyanate composition: urethodione groups provide low viscosity locally, isocyanurate groups provide crosslinkability locally, and allophanate groups provide storage stability locally. This functional differentiation allows each component to optimize its specific property without compromising the overall performance.
3Duration of action of moving object
If polyisocyanate composition is designed for low viscosity, then viscosity is reduced, but crosslinkability becomes insufficient
Solution Approach 1:
The patent creates a multi-component composite where urethodione group-containing polyisocyanate (5-30 mass%) provides low viscosity, while isocyanurate group-containing polyisocyanate (70-95 mass%) provides high crosslinkability. The allophanate group-containing polyisocyanate (1-30 mass%) enhances storage stability. This composite formulation simultaneously achieves low viscosity and high crosslinkability.
Solution Approach 2:
The patent optimizes the concentration parameters of each component to achieve the desired balance. By setting urethodione content at 5-30 mass% and isocyanurate content at 70-95 mass%, the invention maintains low viscosity while ensuring sufficient crosslinkability for high-performance coating films.
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 exhibits improved crosslinkability, storage stability, and adhesiveness, maintaining low viscosity and preventing diisocyanate monomer formation, thus enhancing the physical properties and weather resistance of coated films.
Implementation Method 1
controlled isocyanuration, allophanation, and urethodionation reactions
Implementation Method 2
controlled isocyanuration, allophanation, and urethodionation reactions
Implementation Method 3
controlled isocyanuration, allophanation, and urethodionation reactions
Data Source
AI summary
Disclosed is a polyisocyanate composition derived from an aliphatic diisocyanate monomer and an alcohol, which satisfies all the conditions below in a state not containing the aliphatic diisocyanate monomer and a solvent. 1) Isocyanurate trimer concentration: 55-95 mass% 2) Number ratio of allophanate groups derived from the alcohol to isocyanurate groups: 1-20% 3) Urethodione dimmer concentration: 2-25 mass% 4) Viscosity at 25°C: 150-800 mPa·s