Polyisocyanate Intumescent Coating Fast Curing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current intumescent coatings for steel structures in fire situations have long drying times, making it impractical to apply and transport them on the same day, leading to construction delays and increased costs, and they require multiple coats with intermediate curing, which extends the overall process.
Innovation Solution
A fast-curing intumescent polyurethane coating composition containing a polyisocyanate, a polyfunctional isocyanate-reactive compound, and intumescent ingredients with phosphorus, nitrogen, and boron atoms, which allows for quick drying and thick film application without sagging or intermediate curing, providing enhanced fire resistance and weather resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional intumescent coatings are applied to steel structures, then fire resistance protection is achieved, but drying time becomes excessively long (making same-day application and transport impractical)
Solution Approach 1:
The patent modifies the chemical composition parameters of the coating by incorporating specific catalysts (metal salts like zinc, calcium, or strontium halides at 0.1-5 wt%), adjusting polyol to polyisocyanate ratios, and selecting particular intumescent ingredient combinations to accelerate the curing reaction while preserving fire resistance properties
Solution Approach 2:
The patent creates a composite coating system combining polyisocyanate, polyol, catalyst, and intumescent ingredients (ammonium polyphosphate, melamine, pentaerythritol) into an integrated formulation that simultaneously provides fast curing and fire protection functions
2Reliability
If conventional intumescent coatings are applied to achieve sufficient thickness, then fire resistance is improved, but multiple coats with intermediate curing are required, extending the overall process time
Solution Approach 1:
The patent incorporates catalysts and reactive components in the initial coating formulation that enable the coating to begin curing immediately upon application, allowing thick films to start forming a protective skin before sagging occurs, eliminating the need for intermediate curing between coats
Solution Approach 2:
The patent adjusts viscosity parameters through selective solvent selection and polyol molecular weight control to enable thick film application in a single coat while maintaining sag resistance, combined with accelerated catalyst systems that cure the coating quickly enough to prevent running
3Productivity
If fast-curing ingredients are added to reduce drying time, then productivity is improved, but the coating may sag or run when applied in thick films
Solution Approach 1:
The patent creates different functional zones within the coating formulation: thixotropic agents (colloidal silica, bentonite clay at 1-10 wt%) provide local structural support to prevent sagging, while catalysts (metal halides at 0.1-5 wt%) localized in the formulation accelerate curing in the bulk, allowing thick application without running
Solution Approach 2:
The patent utilizes time-dependent rheological changes where the coating transitions from a flowable state during application to a rigidifying state as curing progresses, with thixotropic properties enabling the coating to remain stable in thick applications while gradually developing structural integrity
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 coating achieves touch-dry in less than 5 minutes, offers 60-120 minutes of fire resistance, and allows for thick film application without sagging, reducing drying times significantly, while maintaining excellent mechanical properties and weather resistance.
Implementation Method 1
a binder containing polyol and polyisocyanate components
Implementation Method 2
the reaction of the acidic species with the carbonization agent takes place with formation of ester mixtures, followed by the carbonization process
Implementation Method 3
the spumific agent decomposes to yield gaseous products which cause the char to swell
Implementation Method 4
produce an insulating foam or 'char'... which has a volume many times that of the original coating
Implementation Method 5
forms a heat resistant barrier which keeps the steel cool... An insulating foam or 'char' having low thermal conductivity
Data Source
AI summary
Intumescent coating composition comprising a polyisocyanate, a polyfunctional isocyanate-reactive compound and an intumescent ingredient, wherein the intumescent ingredient contains at least one or more compounds containing phosphorus, nitrogen and boron atoms and the weight ratio phosphorus to nitrogen in said intumescent ingredient is between 0.5/1 to 1.5/1 and the amount of boron is from 1 to 5 wt % based on the coating composition.