Non-aqueous Coating Agent with Silane Crosslinkers
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Solution Overview
Problem
Current coating systems for heat-sensitive substrates that cure at ambient temperature face challenges in achieving high mechanical resistance and scratch resistance due to the toxicity and limited reactivity of existing crosslinkers and catalysts, which are not suitable for low-temperature curing.
Innovation Solution
A non-aqueous coating agent comprising a crosslinker component of aliphatic or cycloaliphatic di- or polyisocyanates reacted with secondary aminosilanes, combined with organic carboxylic acids or tetraalkylammonium carboxylates as catalysts, allowing curing at temperatures between 10°C to 80°C, resulting in coatings with high mechanical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-reactivity crosslinkers are used to achieve rapid curing at ambient temperature, then curing speed is improved, but toxicological risk increases
Solution Approach 1:
The patent changes the chemical parameters of the crosslinking system by using silane crosslinkers with specific functional groups (epoxy, aziridine, isocyanate) that react with hydroxyl groups in the resin. The curing temperature parameter is optimized to 20-80°C, and catalyst concentration is precisely controlled (0.01-5 wt%) to achieve rapid curing while maintaining low toxicity throughout the process.
Solution Approach 2:
The patent creates a composite coating system combining silane-modified resins with specific crosslinkers and catalysts. This composite approach integrates multiple functional components: the silane groups provide crosslinking capability, the hydroxyl groups enable reaction with crosslinkers, and the catalyst system accelerates curing at ambient temperatures, achieving both high performance and low toxicity.
2Reliability
If heat-curing silane systems are used to achieve high chemical and weather resistance, then coating durability is improved, but curing temperature requirement increases
Solution Approach 1:
The patent fundamentally changes the curing temperature parameter from conventional heat-curing requirements (>120°C) to ambient temperature range (20-80°C). This is achieved by selecting crosslinkers with appropriate reactivity (epoxy, aziridine, isocyanate groups) and optimizing catalyst concentration (0.01-5 wt%) to enable the silane crosslinking reaction to proceed rapidly at low temperatures while maintaining complete cure and coating durability.
Solution Approach 2:
The patent introduces catalysts as intermediary substances that mediate the crosslinking reaction between silane groups and hydroxyl groups. The catalyst lowers the activation energy barrier, enabling the reaction to proceed at ambient temperatures. The catalyst concentration is precisely controlled (0.01-5 wt%) to achieve optimal curing rate without requiring elevated temperatures, thus maintaining coating durability while eliminating heat-curing requirements.
3Productivity
If blocked sulfonic acid catalysts are used to achieve controlled curing, then catalyst activity is improved at high temperature, but low-temperature curing capability is lost
Solution Approach 1:
The patent changes the catalyst selection criteria by abandoning blocked sulfonic acid catalysts (which require >100°C for activity) in favor of catalysts that are active at ambient temperatures (20-80°C). The catalyst concentration is optimized to 0.01-5 wt% to provide sufficient activity at low temperatures. This parameter change enables the coating to cure completely at ambient temperatures while maintaining high catalyst activity and coating performance.
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 system achieves scratch-resistant coatings with a reactivity profile comparable to industry-standard 2-component PUR paints, while being free of water and using less toxic catalysts, thus overcoming the limitations of existing systems.
Implementation Method 1
from 0.05 to 5% by weight of at least one catalyst selected from C1) at least one organic carboxylic acid with a melting point of at least 60 °C and / or C2) at least one tetraalkylammonium carboxylate
Implementation Method 2
They consist of paint resins with functional groups and crosslinkers that react with these functional groups to form crosslinking even at ambient temperature
Data Source
AI summary
Non-aqueous coating material comprises (A) at least one crosslinker component consisting of at least one aliphatic and/or cycloaliphatic polyisocyanate having an isocyanate (NCO)-functionality of 2-6, where at least 90 mole% of the free isocyanate groups originally present in the diisocyanate or polyisocyanate having undergone reaction with at least one secondary aminosilane compound (I), (B) optionally one or more binder components, (C) 0.05-5 wt.% of at least one catalyst, (D) optionally one or more auxiliaries and/or adjuvants, and (E) optionally one or more organic solvents. Non-aqueous coating material comprises: (A) at least one crosslinker component consisting of at least one aliphatic and/or cycloaliphatic polyisocyanate having an isocyanate (NCO)-functionality of 2-6, where at least 90 mole% of the free isocyanate groups originally present in the diisocyanate or polyisocyanate having undergone reaction with at least one secondary aminosilane compound of formula (R1(NH)-X-Si(OR) 3 x-(Rx)) (I), (B) optionally one or more binder components, (C) 0.05-5 wt.% of at least one catalyst consisting of (C1) at least one organic carboxylic acid having a melting point of at least 60[deg] C and/or (C2) at least one tetraalkylammonium carboxylate, (D) optionally one or more auxiliaries and/or adjuvants, and (E) optionally one or more organic solvents. R1 : X-Si(OR) 3 x-Rx; R : alkyl, cycloalkyl, aryl or aralkyl having 1-10C, where the carbon chain is interrupted by non-adjacent O, S, or NR1a groups; R1a : alkyl, cycloalkyl, aryl or aralkyl having 1-10C; X : 1-20C-hydrocarbyl; and x : 0-2.