Solventless Adhesive High Molecular Weight Oligomers
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Solution Overview
Problem
Conventional two-component solventless adhesives fail to provide strong bonds in applications involving reverse printed film to metallized film and reverse printed PET film with water-base inks, leading to issues like demetallization and ink decal, due to their relatively lower molecular weight monomers and oligomers.
Innovation Solution
A two-component solventless adhesive composition with high molecular weight oligomers (above 3,000 g/mole) and an isocyanate reactive curative, which forms a cured adhesive layer that improves bond strength and prevents decaling in laminated structures, particularly suitable for applications where conventional adhesives perform poorly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional two-component solventless adhesives with lower molecular weight monomers and oligomers are used, then the adhesive provides favorable characteristics for many laminating applications, but it causes demetallization or ink decal in specific applications involving reverse printed film to metallized film or water-base inks
Solution Approach 1:
The patent changes the molecular weight parameter of the oligomers from conventional lower molecular weight (acting as reactive diluents) to higher molecular weight oligomers (at least 3,000 g/mole). This parameter change eliminates the harmful demetallization and ink decal effects while maintaining the adhesive's functionality and favorable characteristics for laminating applications.
2Strength
If high molecular weight oligomers (at least 3,000 g/mole) are used in the adhesive composition, then bond strength is improved and decaling is prevented, but the adhesive viscosity may increase making application more difficult
Solution Approach 1:
The patent changes the molecular weight parameter of oligomers to at least 3,000 g/mole, which improves bond strength and prevents decaling. The formulation balances this parameter change with other adhesive components to maintain acceptable viscosity for application.
3Ease of manufacture
If two-component solventless adhesive is used instead of solvent-borne or water-borne laminating adhesives, then costs are reduced and environmental friendliness is improved, but it fails to provide strong bonds in specific applications like reverse printed PET to metallized PET or water-base ink to secondary films
Solution Approach 1:
The patent modifies the oligomer molecular weight parameter in two-component solventless adhesives to at least 3,000 g/mole. This parameter change enables the adhesive to achieve strong bonds in challenging applications (reverse printed PET to metallized PET, water-base ink to secondary films) while maintaining the cost and environmental advantages of solventless technology.
Solution Approach 2:
The patent creates a composite adhesive formulation combining high molecular weight oligomers (at least 3,000 g/mole) with isocyanate and isocyanate reactive curative. This composite material approach provides the bond strength and reliability needed for difficult laminating applications while preserving the benefits of two-component solventless adhesive technology.
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 high molecular weight oligomer-based adhesive enhances bond strength, reduces decaling, and maintains low viscosity for easy application, providing better performance in challenging applications such as reverse printed PET to metallized PET and water-base ink to secondary films.
Implementation Method 1
a cured adhesive layer bonding the first substrate to the second substrate comprising a solventless two-component adhesive composition which prior to curing has - a prepolymer part comprising a first oligomer and an isocyanate, and - a curative part comprising an isocyanate reactive component
Data Source
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AI summary
Two-component solventless adhesive compositions for lamination applications and laminated structures, including flexible laminated packaging, comprising at least two substrates, including structures comprising reverse printed ink films and/or metallized films. The adhesive comprises a prepolymer having one or more oligomers with a relatively high molecular weight.