Polyisocyanate Composition Balancing Fast Cure and Coating Durability
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Solution Overview
Problem
Existing polyurethane resins face challenges in achieving excellent appearance, durability, weather resistance, chemical resistance, and fast curing properties while maintaining high productivity.
Innovation Solution
A polyisocyanate composition comprising modified xylylene diisocyanate and pentamethylene diisocyanate, with a specific mole ratio, containing isocyanurate groups, is used to produce a polyurethane resin through a reaction with an active hydrogen group-containing compound, forming a two-component curable polyurethane composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyisocyanate compositions are used to produce polyurethane resin, then basic curing properties are achieved, but excellent appearance, durability, weather resistance, chemical resistance, and fast curing properties cannot be simultaneously obtained while maintaining high productivity
Solution Approach 1:
The patent applies parameter changes by precisely controlling the mole ratio of pentamethylene diisocyanate to total diisocyanate within 5-40 mol%, and controlling the isocyanate group concentration at 20-40 mass%. These specific parameter ranges optimize the balance between durability (weather resistance, chemical resistance) and productivity, allowing the polyurethane resin to achieve excellent performance without compromising production efficiency.
Solution Approach 2:
The patent uses a composite polyisocyanate composition containing multiple components: modified xylylene diisocyanate, modified pentamethylene diisocyanate, and their copolymer. This composite structure combines the advantages of different diisocyanates to achieve superior durability, weather resistance, and chemical resistance while maintaining fast curing properties and high productivity.
2Speed
If polyisocyanate composition with high isocyanate group concentration is used, then fast curing properties are achieved, but compatibility with active hydrogen group-containing compound and appearance quality deteriorate
Solution Approach 1:
The patent optimizes the isocyanate group concentration to a specific range of 20-40 mass%, avoiding both too low (slow curing) and too high (poor appearance) concentrations. Additionally, the controlled mole ratio of pentamethylene diisocyanate (5-40 mol%) ensures fast curing while maintaining compatibility and appearance quality.
3Reliability
If polyisocyanate composition is optimized for excellent appearance and durability, then weather resistance and chemical resistance are improved, but curing properties and productivity may be compromised
Solution Approach 1:
The patent employs a composite polyisocyanate system containing xylylene diisocyanate (providing weather resistance), pentamethylene diisocyanate (providing fast curing), and their copolymer. This composite structure ensures that weather resistance and curing efficiency are both optimized without compromising productivity.
Solution Approach 2:
The patent controls the mole ratio of pentamethylene diisocyanate at 5-40 mol% to balance weather resistance (from xylylene diisocyanate) and curing speed (from pentamethylene diisocyanate), while the isocyanate group concentration of 20-40 mass% ensures efficient curing without sacrificing productivity.
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 resulting polyurethane resin exhibits excellent appearance, durability, weather resistance, chemical resistance, and fast curing properties, all achieved with improved productivity.
Implementation Method 1
A polyurethane resin is usually produced by reaction of polyisocyanate with an active hydrogen group-containing compound
Implementation Method 2
the modified product of xylylene diisocyanate is modified with an alcohol and contains an isocyanurate group (a)
Data Source
Figure 1
AI summary
A polyisocyanate composition contains a modified product of xylylene diisocyanate and a modified product of pentamethylene diisocyanate, and/or a modified product of the xylylene diisocyanate and the pentamethylene diisocyanate. The ratio of the pentamethylene diisocyanate with respect to the total amount of the xylylene diisocyanate and the pentamethylene diisocyanate is 5 mol% or more and 40 mol% or less.