Two-Component Paint Composition with Low-Isocyanate Hardener
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Solution Overview
Problem
Existing two-component coating systems using polyfunctional isocyanates in aerosol cans release toxic monomeric and dimeric components, exceeding legal limits, posing health risks to users.
Innovation Solution
A two-component coating system where the hardener component is pre-reacted with bi- or trifunctional, low-molecular-weight active hydrogen compounds to reduce monomeric and dimeric isocyanate content to ≤ 1% w/w, using alcohols or amines, and is applied in an aerosol can with an inner sleeve for controlled mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyfunctional isocyanates are used as hardener component, then crosslinking efficiency is improved, but toxic monomeric and dimeric components are released exceeding legal limits
Solution Approach 1:
The patent applies preliminary action by pre-reacting a portion of the isocyanate groups with polyols before formulation, creating oligomeric hardener components that retain crosslinking capability while reducing toxic monomeric content. This pre-reaction is performed during manufacturing, allowing the product to be ready for use with reduced harmful components from the start.
Solution Approach 2:
The patent changes the molecular weight parameter of the hardener component by converting monomeric isocyanates into oligomeric forms through controlled pre-reaction with polyols. This parameter change reduces volatility and toxicity while maintaining the crosslinking function, directly addressing the contradiction between efficiency and safety.
2Speed
If monomeric isocyanates are used, then reactivity and crosslinking speed are improved, but health risks to users increase
Solution Approach 1:
The patent applies local quality by creating a heterogeneous hardener system containing both oligomeric components (from pre-reaction) and residual monomeric isocyanates. The oligomeric portions provide bulk mass with reduced toxicity, while controlled amounts of monomeric isocyanates remain to ensure adequate reactivity and crosslinking speed, achieving local optimization of different properties within the same component.
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
Reduces toxic isocyanate exposure by encapsulating the pre-reacted hardener in the aerosol can, ensuring minimal release of respirable particles and maintaining effective crosslinking, thus complying with legal limits and enhancing user safety.
Implementation Method 1
the binder in the binder component crosslinks through contact with the hardener component
Implementation Method 2
a conventional two-component aerosol can with an inner sleeve
Implementation Method 3
the hardener component is obtainable by pre-reaction from a sub-stoichiometric amount of a bi- or trifunctional low-molecular-weight active hydrogen-bearing compound with an isocyanate-based crosslinker
Data Source
AI summary
The invention relates to a two-component paint system comprising a binder component and a curing agent component which are separated from each other prior to applying the paint system and are brought into contact with each other in order to be applied so that the binder in the binder component is crosslinked by contacting the curing agent component. Along with the binder, the binder component has at least one solvent which does not react with the curing agent component, a cross-linking catalyst, and a foaming agent. The invention is characterized in that the curing agent component can be obtained from a deficient amount of a bi- or tri-functional low-molecular hydrogen-containing active compound by means of a preliminary reaction with an isocyanate-based cross-linking agent with a remaining content of monomeric or dimeric isocyanates of ≤ 1 % w/w. The two-component paint system is contained in a 2K aerosol can with an inner sleeve.