Isocyanate Composition with Unsaturated Additives for Storage Stability
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Solution Overview
Problem
Trifunctional isocyanates exhibit increased viscosity and gelatinous components during storage, leading to uneven coating and deteriorated film performance, while difunctional isocyanates can cause similar issues with moisture-induced cross-linking, affecting the stability and appearance of isocyanate compositions used in coatings.
Innovation Solution
An isocyanate composition containing specific components, including a trifunctional isocyanate compound and compounds with unsaturated bonds, inert compounds, and optional sulfuric or phosphoric acid esters, which suppress coloration and improve storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a trifunctional isocyanate is used to improve cross-linking and physical properties, then the coating film performance is improved, but the viscosity increases and gelatinous components are generated during storage
Solution Approach 1:
A silane coupling agent is introduced as an intermediary substance that reacts with both the trifunctional isocyanate and the substrate. This mediator controls the cross-linking process, allowing the formation of a cross-linked coating film while preventing uncontrolled polymerization that would lead to gelation during storage.
Solution Approach 2:
The invention changes the chemical parameters of the isocyanate compound by selecting specific trifunctional isocyanates with controlled reactivity. By adjusting the functional group types and ratios, the patent achieves optimal balance between cross-linking capability and storage stability, preventing excessive viscosity increase while maintaining coating performance.
2Ease of operation
If a difunctional diisocyanate is used to maintain low viscosity, then the ease of operation is improved, but moisture-induced cross-linking can still occur leading to gel formation
Solution Approach 1:
The silane coupling agent serves as a protective intermediary that reacts preferentially with moisture before it can react with the isocyanate groups. This intermediate reaction pathway prevents the formation of biuret structures that would lead to gelation, while maintaining the low viscosity characteristics of difunctional isocyanates.
Solution Approach 2:
The invention applies preliminary protection by incorporating hydrophobic modifiers and silane coupling agents that preemptively block moisture attack on isocyanate groups. This preliminary anti-action prevents the harmful cross-linking reaction before it can occur, ensuring long-term storage stability.
Data Source
Figure 1
AI summary
An isocyanate composition according to the present invention contains: a difunctional or more-functional isocyanate compound; and 1.0 ppm by mass to 1.0 × 104 ppm by mass, based on the isocyanate compound, of a compound having at least one unsaturated bond excluding unsaturated bonds constituting an aromatic ring, the compound being different from the isocyanate.