Polyaspartic Coatings Viscosity and Flexibility via Isocyanate Blends
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Solution Overview
Problem
Polyaspartic ester-based coatings have short pot lives and limited flexibility, often requiring solvents and catalysts that are volatile organic compounds (VOCs) and toxic, respectively, which complicates their application and environmental impact.
Innovation Solution
A composition comprising a polyaspartic ester and an isocyanate compound mixture with an NCO content greater than 13% and viscosity less than 1500 mPa·s, utilizing a blend of allophanate and polyfunctional isocyanate, potentially without solvents or catalysts, to enhance flexibility and reduce viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If solvents are used to reduce viscosity and extend pot life, then the composition becomes easier to handle and applies longer, but volatile organic compounds (VOCs) are introduced which harm the environment and health
Solution Approach 1:
The patent changes the chemical parameters of the isocyanate compound by using a specific mixture of allophanate and polyfunctional isocyanate in a mass ratio of 50/50 to 99/1, achieving an NCO content greater than 13% and viscosity less than 1500 mPa·s at 25°C. This parameter optimization allows the composition to achieve acceptable viscosity and extended pot life without requiring VOC solvents
Solution Approach 2:
The patent creates a composite isocyanate system by combining allophanate (b1) and polyfunctional isocyanate (b2) in a specific mass ratio. This composite approach leverages the complementary properties of both isocyanate types to achieve the desired balance between viscosity, NCO content, and pot life without needing additional solvents
2Ease of operation
If elastomeric isocyanate prepolymer compounds are added to improve flexibility, then elongation at break increases, but the NCO content decreases below 13% and viscosity increases above 1500 mPa·s
Solution Approach 1:
The patent optimizes the parameters of the isocyanate compound by selecting a specific mixture composition where the mass ratio of allophanate to polyfunctional isocyanate is between 50/50 and 99/1. This parameter control ensures that the NCO content remains greater than 13% and viscosity stays below 1500 mPa·s at 25°C, while achieving elongation at break greater than 50%
Solution Approach 2:
The patent applies local quality by specifying that the polyaspartic ester compound (a) should have an NH group content of between 2% and 8% by mass, and the isocyanate compound (b) should have specific properties (NCO content >13%, viscosity <1500 mPa·s). This localized optimization of material properties enables flexibility improvement without compromising the required NCO content and viscosity specifications
3Productivity
If catalysts are added to accelerate crosslinking, then the reaction speed increases, but toxicity to handlers and the environment increases
Solution Approach 1:
The patent extracts and eliminates the catalyst component from the composition entirely. By using a carefully balanced mixture of allophanate and polyfunctional isocyanate with specific properties (NCO content >13%, viscosity <1500 mPa·s), the system achieves acceptable crosslinking speed without requiring any catalyst, thereby eliminating the associated toxicity issues
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 solution achieves improved elongation at break greater than 50% and acceptable viscosity, making the coatings more flexible and easier to apply, while reducing the need for VOCs and toxic catalysts, particularly suitable for ground covering and wind power applications.
Implementation Method 1
a polyaspartic ester compound (a) and an isocyanate compound (b)
Data Source
AI summary
The invention relates to compositions for coating preparations comprising at least one polyaspartic ester compound, at least one isocyanate compound and optionally at least one additive.