Formaldehyde-free binder composition
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Solution Overview
Problem
Existing binder compositions for textile sheet products, particularly nonwovens, often rely on N-methylolacrylamide units that form formaldehyde during crosslinking, posing toxicological concerns and requiring a reduction in formaldehyde content to produce formaldehyde-free products.
Innovation Solution
An aqueous binder composition is developed through radically initiated polymerization of vinyl acetate and ethylene in the presence of polyvinyl alcohol, with specific weight percentages of acrylamide, methacrylamide, and maleic anhydride, avoiding the use of formaldehyde-releasing substances and catalysts to achieve high wet strength without formaldehyde release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If N-methylolacrylamide units are used in binder polymers to achieve crosslinking and high strength, then the strength and durability of textile sheet products are improved, but formaldehyde is released during crosslinking which is toxicological concern
Solution Approach 1:
The invention extracts and removes the harmful N-methylolacrylamide crosslinking units from the binder polymer composition, replacing them with alternative monomers that do not release formaldehyde. This eliminates the source of formaldehyde release while maintaining the crosslinking functionality through other chemical mechanisms.
Solution Approach 2:
The invention changes the chemical composition parameters of the binder polymer by specifying alternative monomer units (acrylamide, methacrylamide, carboxylic acid groups) with specific weight percentages. This parameter change transforms the crosslinking mechanism from formaldehyde-based to alternative chemistry-based, eliminating toxicological concerns.
2Productivity
If formaldehyde-releasing initiators such as sodium formaldehyde-sulfoxylate are used in polymerization, then polymerization efficiency is improved, but formaldehyde is incorporated as a concomitant in the final product
Solution Approach 1:
The invention extracts and removes formaldehyde-releasing initiators from the polymerization process, replacing them with alternative initiating systems that do not incorporate formaldehyde into the polymer structure. This eliminates both the source of formaldehyde release and the incorporation of formaldehyde as a concomitant.
3Strength
If crosslinking catalysts are added to enhance binder performance, then the binding strength is improved, but the complexity of the formulation and potential for harmful byproducts increases
Solution Approach 1:
The invention extracts and removes crosslinking catalysts from the binder formulation, achieving crosslinking through inherent chemical reactions of the monomer units (carboxylic acid groups reacting with hydroxyl groups on fibers) rather than requiring external catalysts. This simplifies the formulation while maintaining binding strength.
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 binder composition achieves high wet strength for fiber assemblies without the need for crosslinking catalysts and minimizes formaldehyde content, ensuring the production of formaldehyde-free textile sheet products.
Implementation Method 1
obtainable by radically initiated polymerization of vinyl acetate and ethylene
Implementation Method 2
polyvinyl alcohol-stabilized vinyl acetate-ethylene copolymers
Implementation Method 3
high wet strength of the fiber assembly even without addition of crosslinking catalyst
Data Source
AI summary
An aqueous binder composition. The aqueous binder composition is obtainable by radically initiated polymerization of vinyl acetate and ethylene, in the presence of polyvinyl alcohol in an aqueous medium, wherein (a) 50 to 94 wt % of vinyl acetate, (b) 5 to 40 wt % of ethylene, (c) 0.2 to 5 wt % of acrylamide and/or methacrylamide, and (d) 0.2 to 5 wt % of maleic anhydride and/or maleic acid are copolymerized in the presence of a polyvinyl alcohol having a degree of hydrolysis of 80 to 99 mol %. The amounts in wt % are each based on the total weight of the comonomers and add up in each case to 100 wt %.