Core-shell aqueous latex
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Solution Overview
Problem
Existing latex polymers used for textile treatments often release formaldehyde during crosslinking and require high temperatures for crosslinking, which are undesirable, and they lack stability and sufficient tensile strength.
Innovation Solution
An aqueous composition of latex polymer particles with a core polymer comprising 95% monofunctional vinyl monomers and 5% multivinyl monomers, and a shell polymer containing 35% to 95% monofunctional vinyl monomers and 5% to 65% vinyl monomers with latent crosslinking groups such as trialkoxysilyl or oxoacetyl groups, allowing for low-temperature crosslinking without formaldehyde release and providing stability and high tensile strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional latent crosslinking monomers (amide or N-alkylolamide of alpha, beta ethylenically unsaturated carboxylic acid) are used in the shell polymer, then crosslinking capability is achieved, but formaldehyde is released during the crosslinking process
Solution Approach 1:
The patent changes the chemical parameters of the crosslinking monomer by selecting from specific groups (trialkoxysilyl, oxoacetyl, carboxyl, hydroxyl, amino groups) that do not release formaldehyde during crosslinking, while maintaining the crosslinking functionality through alternative chemical mechanisms
Solution Approach 2:
The patent eliminates the harmful formaldehyde release by using alternative crosslinking chemistry that achieves the same crosslinking effect without the harmful byproduct, effectively converting a harmful process into a benign one
2Reliability
If high temperatures are used for crosslinking after application to substrate, then crosslinking reaction proceeds effectively, but the process becomes undesirable due to energy consumption and potential substrate damage
Solution Approach 1:
The patent changes the activation energy parameters of the crosslinking system by using monomers with latent crosslinking groups that can react at lower temperatures, thereby reducing the cure temperature from high to relatively low while maintaining crosslinking effectiveness
Solution Approach 2:
The patent replaces thermal activation (high temperature) with alternative activation mechanisms that enable crosslinking at lower temperatures, substituting the need for high thermal energy with chemistry that proceeds under milder conditions
3Reliability
If the latex polymer is designed for crosslinking capability, then functional performance is improved, but storage stability deteriorates due to premature crosslinking reactions
Solution Approach 1:
The patent incorporates latent crosslinking groups during polymer synthesis that remain dormant during storage and only activate under specific conditions (heat, moisture, catalyst) after application, thus preparing the crosslinking capability in advance while preventing premature reaction through conditional activation
Solution Approach 2:
The patent uses latent crosslinking groups as intermediaries that bridge the core and shell polymers without causing premature crosslinking, acting as dormant functional groups that activate only when appropriate conditions are met, thus mediating between storage stability and crosslinking functionality
4Temperature
If core-shell structure with latent crosslinking groups is implemented, then low-temperature crosslinking is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent divides the polymer into core and shell segments with distinct functions: the core provides structural integrity while the shell contains the latent crosslinking groups, allowing independent optimization of each segment and simplifying the overall design despite the multicomponent nature
Solution Approach 2:
The patent creates a composite latex polymer combining core polymer and shell polymer with latent crosslinking groups, where the synergistic interaction between components achieves low-temperature crosslinking while the modular composite structure actually simplifies manufacturing by allowing separate synthesis and combination of functional elements
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 composition achieves stable storage, low-temperature crosslinking, and high tensile strength in textiles, comparable to or exceeding commercial binders, with minimal formaldehyde release and reduced dependence on cure temperature for effective bonding.
Implementation Method 1
a shell polymer that comprises (i) 35% to 95% by weight, based on the dry weight of the shell polymer, polymerized units of one or more monofunctional vinyl monomers, and (ii) 5% to 65% by weight, based on the dry weight of the shell polymer, polymerized units of one or more vinyl monomers having a latent crosslinking group selected from the group consisting of trialkoxysilyl groups, oxoacetyl groups, and mixtures thereof
Data Source
AI summary
Provided is an aqueous composition comprising latex polymer particles that comprise(a) 40% to 95%, by weight based on the dry weight of the latex polymer, a core polymer that comprises(i) polymerized units of one or more monofunctional vinyl monomers, and(ii) polymerized units of one or more multivinyl monomers, and(b) 5% to 60%, by weight based on the dry weight of the latex polymer, a shell polymer that comprises(i) polymerized units of one or more monofunctional vinyl monomers, and(ii) polymerized units of one or more vinyl monomers having a latent crosslinking group selected from the group consisting of trialkoxysilyl groups, oxoacetyl groups, and mixtures thereof.