Aqueous Polyurethane Dispersion for Metal Foil Lamination
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Solution Overview
Problem
Existing waterborne adhesive compositions for laminating metal foils to polymer films face challenges in stability, adhesion, and cost, particularly when using aliphatic isocyanates, which are expensive and not suitable for dry bond lamination methods.
Innovation Solution
Aqueous polyurethane dispersions are developed using aromatic isocyanates, with specific compositions including polyester polyols, diols with hydrophilic side chains, and other polyols, along with anionic surfactants, to create a stable and cost-effective adhesive for dry bond lamination, providing strong adhesion between metal foils and polymer films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If aromatic isocyanates are used instead of aliphatic isocyanates, then cost is reduced, but adhesion performance and stability may worsen
Solution Approach 1:
The patent modifies the chemical structure parameters of the polyol component by incorporating diols with hydrophilic side chains containing anionic groups. This parameter change enables the use of cheaper aromatic isocyanates while maintaining adhesion performance through improved water compatibility and dispersion stability.
Solution Approach 2:
The invention creates a composite polyol system combining polyester polyols with diols having hydrophilic side chains. This composite material approach allows the adhesive to achieve both cost-effectiveness (through aromatic isocyanates) and reliable adhesion (through the specialized polyol composition).
2Object-affected harmful factors
If waterborne adhesive compositions are used for dry bond lamination, then safety and environmental protection are improved, but adhesion strength may worsen
Solution Approach 1:
The patent changes the chemical parameters of the polyol component to include diols with hydrophilic side chains containing anionic groups. This modification enables waterborne formulations to achieve adhesion strengths comparable to or exceeding traditional solvent-based adhesives, thereby maintaining safety and environmental benefits while improving adhesion performance.
3Stability of the object's composition
If aqueous polyurethane dispersions are made stable during storage, then storage stability is improved, but adhesion performance may worsen
Solution Approach 1:
The patent optimizes the molecular structure parameters of the polyol component by incorporating diols with specific hydrophilic side chains. This parameter optimization achieves a balance where the adhesive maintains stability during storage while preserving or enhancing adhesion performance through improved water compatibility and controlled phase behavior.
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 solution provides stable, cost-effective aqueous polyurethane dispersions that ensure strong adhesion between metal foils and polymer films, maintaining stability during storage and demonstrating high bond strength in dry bond lamination processes.
Implementation Method 1
aqueous composition comprising one or more anionic surfactants and further comprising dispersed particles that comprise a polyurethane
Implementation Method 2
one or more diols having a hydrophilic side chain, wherein said hydrophilic side chain comprises one or more anionic group
Implementation Method 3
said polyurethane is a reaction product of a group of reactants (GR1), wherein GR1 comprises one or more aromatic polyisocyanates and, a polyol component
Data Source
AI summary
Provided is an aqueous composition comprising dispersed particles that comprise a polyurethane, wherein said polyurethane is a reaction product of a group of reactants (GR1), wherein GR1 comprises one or more aromatic polyisocyanates and, a polyol component, wherein said polyol component comprises(a) 50% to 99% by weight, based on the weight of said polyol component, one or more polyester polyols,(b) 0.1% to 10% by weight, based on the weight of said polyol component, one or more diols having a hydrophilic side chain, and(c) 0.9% to 40% by weight, based on the weight of said polyol component, one or more polyols different from (a) and (b).Also provided is a method of bonding a metal foil to a polymer film using such an aqueous composition.