Cyclic N,O Acetal Monomers for Formaldehyde-Free Crosslinking
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Solution Overview
Problem
Existing polymers used in textile binders and coatings, such as those containing N-methylol acrylamide, emit formaldehyde during the curing process, posing a challenge for achieving solvent-resistant and formaldehyde-free crosslinked polymers.
Innovation Solution
Development of cyclic N,O acetal compounds with specific structural formulas that can be used as ethylenic monomers, allowing for the creation of crosslinkable polymers that self-crosslink under acid catalysis or thermosetting conditions without formaldehyde release, using monomers like 2-(2-hydroxy-5-oxopyrrolidin-1-yl)ethyl acrylate and 2-(1-hydroxy-3-oxoisoindolin-2-yl)ethyl acrylate, which are free radical polymerizable and react with active hydrogen compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If N-methylol containing binders such as N-methylol acrylamide are used to achieve crosslinking ability and solvent resistance, then crosslinking performance is improved, but formaldehyde is emitted during the curing process
Solution Approach 1:
The invention changes the chemical structure parameter by replacing N-methylol groups with cyclic N,O acetal groups (specifically tetrahydro-2H-pyran-2-yl and similar structures). This structural parameter change maintains the crosslinking functionality while eliminating formaldehyde emission, as the acetal groups undergo acid-catalyzed decomposition and crosslinking without releasing formaldehyde.
Solution Approach 2:
The invention converts the previously harmful formaldehyde-releasing mechanism into a beneficial formaldehyde-free crosslinking process. By using cyclic N,O acetal monomers that decompose under acid catalysis to form crosslinks without formaldehyde emission, the harmful byproduct is eliminated while maintaining the desired crosslinking performance for solvent resistance and adhesion.
2Stability of the object's composition
If conventional crosslinkable polymers are used to achieve solvent resistance, then solvent resistance is improved, but formaldehyde release occurs during curing
Solution Approach 1:
The invention modifies the chemical composition parameter by incorporating cyclic N,O acetal monomers (containing tetrahydro-2H-pyran-2-yl or similar groups) into the polymer structure. This compositional change enables the polymer to achieve solvent resistance through crosslinking while eliminating formaldehyde release, as the acetal groups provide crosslinking functionality without the harmful byproduct.
3Strength
If N-methylol acrylamide is used to achieve crosslinking ability, then crosslinking performance is improved, but the binder is not formaldehyde free
Solution Approach 1:
The invention changes the functional group parameter by replacing N-methylol groups with cyclic N,O acetal groups (tetrahydro-2H-pyran-2-yl and similar structures). This parameter change maintains the crosslinking ability through acid-catalyzed decomposition and etherification reactions while ensuring the binder is completely formaldehyde-free, thus improving reliability for sensitive applications.
4Productivity
If conventional ethylenic monomers are used for polymerization, then polymerization efficiency is maintained, but the resulting polymers emit formaldehyde during curing
Solution Approach 1:
The invention changes the monomer structure parameter by using cyclic N,O acetal-substituted ethylenic monomers (with tetrahydro-2H-pyran-2-yl or similar groups) instead of conventional monomers like N-methylol acrylamide. This parameter change maintains polymerization efficiency through free radical polymerization while eliminating formaldehyde emission during subsequent curing, as the acetal groups provide crosslinking functionality without releasing formaldehyde.
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 crosslinked polymers exhibit excellent solvent and water resistance, low energy cure, and good adhesion, making them suitable for coatings, binders, or adhesives while being completely free from formaldehyde, suitable for applications in textiles, nonwovens, and medical/surgical uses.
Implementation Method 1
The cyclic N,O acetal monomers of the present invention being olefinically unsaturated can be homopolymerized, or polymerized in any amount
Implementation Method 2
the polymers can self-crosslink under acid catalysis and/or thermosetting conditions
Implementation Method 3
The crosslinking reaction is promoted by heat and the resulting crosslinked polymers are solvent resistant
Implementation Method 4
Moreover, they react with active hydrogen compounds such as alcohols and diols
Data Source
AI summary
The present invention relates to olefinically unsaturated monomers having the general structural formula (I) which can crosslink and which can be homo- and copolymerized with other ethylenic monomers to form crosslinkable polymers useful in coatings, adhesives and textile binders. The crosslinking reaction is promoted by heat and the resulting crosslinked polymers are solvent resistant, showing no formaldehyde release while curing.