Vinyl Acetate-Ethylene Binder Composition Without Formaldehyde Release
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Solution Overview
Problem
Existing binder compositions for textile fabrics, particularly nonwovens, often contain N-methylolacrylamide units that release formaldehyde during crosslinking, posing toxicological concerns and requiring a reduction in formaldehyde content to produce formaldehyde-free textiles.
Innovation Solution
An aqueous binder composition based on vinyl acetate-ethylene copolymers, produced through radically initiated polymerization in the presence of polyvinyl alcohol and a copolymer containing acrylamide, acrylic acid, and maleic anhydride units, which eliminates the need for crosslinking catalysts and avoids formaldehyde release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If N-methylolacrylamide units are used as binder components to achieve covalent bonds between binder polymer and fiber, then fiber binding strength is improved, but formaldehyde is released during crosslinking which creates toxicological concerns
Solution Approach 1:
The invention extracts and removes the harmful N-methylolacrylamide crosslinking units from the binder composition, replacing them with alternative crosslinking mechanisms that do not release formaldehyde. The patent explicitly eliminates NMA units while maintaining fiber binding capability through other means.
Solution Approach 2:
The invention changes the chemical composition parameters of the binder by replacing N-methylolacrylamide units with alternative monomers such as acrylic acid, acrylamide, and maleic anhydride units. This parameter change allows achieving fiber binding without formaldehyde release.
2Strength
If crosslinking monomers are used to increase resistance of textile fabrics to mechanical stress, then fabric strength is improved, but formaldehyde content increases due to production using formaldehyde-releasing initiators
Solution Approach 1:
The invention removes formaldehyde-releasing initiators such as sodium formaldehyde sulfoxylate from the polymerization process, replacing them with alternative initiators that do not introduce formaldehyde into the binder composition.
Solution Approach 2:
The invention uses alternative crosslinking mechanisms that do not rely on persistent formaldehyde groups, instead employing short-lived crosslinking reactions that occur during processing and then complete without leaving harmful residues.
3Strength
If N-methylolacrylamide and acrylamide comonomer units are combined in vinyl acetate-ethylene copolymers to improve wet strength, then wet strength is enhanced, but the complexity of polymer composition increases
Solution Approach 1:
The invention introduces specific functional monomer units (acrylic acid, acrylamide, maleic anhydride) at controlled proportions within the copolymer structure to provide localized wet strength enhancement without requiring complex multi-component formulations.
Solution Approach 2:
The invention creates a composite copolymer structure combining vinyl acetate, ethylene, and functional comonomers (acrylic acid, acrylamide, maleic anhydride) in specific ratios to achieve enhanced wet strength while maintaining manageable composition complexity.
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 textile fibers without formaldehyde release, enhancing the production of formaldehyde-free nonwovens with improved mechanical resistance.
Implementation Method 1
a vinyl acetate-ethylene copolymer A), obtainable by means of radically initiated polymerization of vinyl acetate, ethylene and optionally other ethylenically unsaturated comonomers copolymerizable therewith
Implementation Method 2
N-methylolacrylamide groups can interact with the OH groups of cellulose or starch and consequently lead to covalent bonds between the binder polymer and the fiber
Implementation Method 3
b2) 20 to 50% by weight of monomer units, which are derived from ethylenically unsaturated monocarboxylic acids
Data Source
AI summary
The invention relates to an aqueous binder composition for binding fibers, comprising a vinyl acetate-ethylene copolymer A), which can be obtained by means of the radically initiated polymerization of a1) 60 to 94 wt.% vinyl acetate, a2) 5 to 30 wt.% ethylene and a3) 0 to 20 wt.% of additional, ethylenically unsaturated copolymerizable comonomers, in the presence of polyvinyl alcohol in an aqueous medium, characterized in that the polymerization is carried out in the presence of an interpolymer B) having b1) 20 to 50 wt.% of monomer units derived from ethylenically unsaturated carboxylic amides, b2) 20 to 50 wt.% of monomer units derived from ethylenically unsaturated monocarboxylic acids, b3) 20 to 50 wt.% of monomer units derived from ethylenically unsaturated dicarboxylic acids or their anhydrides, the specifications in wt.% for the monomers a1), a2) and a3) adding up to 100 wt.% and the specifications in wt.% for the monomer units b1), b2) and b3) adding up to 100 wt.%.