Curable Heat-Seal Adhesive for Polymer Laminates
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Solution Overview
Problem
The manufacturing of polymer laminates using solvent-based warm-melt adhesives is constrained by the need for rapid bonding due to solvent evaporation, making it impractical for small or custom orders, and there is a need for adhesive compositions with low tack and high peel strength.
Innovation Solution
A curable composition comprising a urethane (meth)acrylate oligomer, mono(meth)acrylate monomer, multifunctional crosslinking monomer, and ethylene-vinyl acetate grafted terpolymer, which forms a low-tack adhesive layer upon exposure to radiation or heat, allowing for bonding of polymer substrates with improved peel strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If solvent-based warm-melt adhesives are used for bonding polymer substrates, then the adhesive can be applied and bonded quickly, but the solvent evaporates rapidly requiring bonding to occur within a very short time window
Solution Approach 1:
The invention changes the fundamental parameter of adhesive chemistry from solvent-based to moisture-curing polyurethane chemistry. This transformation allows the adhesive to remain workable for extended periods while maintaining bonding capability, effectively resolving the time window constraint without sacrificing bonding speed when needed.
Solution Approach 2:
The invention introduces moisture from the environment as an intermediary curing agent. The moisture-curing mechanism allows the adhesive to progressively cure upon exposure to ambient humidity, providing a flexible time window for bonding operations while ultimately achieving strong adhesion without rapid solvent evaporation constraints.
2Ease of operation
If pre-assembly is performed in anticipation of orders to enable fast turnaround, then customer service improves, but warehouse storage requirements and costs increase
Solution Approach 1:
The invention enables preliminary preparation of adhesive-coated substrates that can be stored without curing. The moisture-curing mechanism allows components to be pre-assembled or pre-coated and then stored at ambient conditions, curing only when final assembly occurs, thereby reducing the need for large warehouses while maintaining fast order fulfillment capability.
3Ease of manufacture
If warm-melt adhesives are used instead of hot-melt adhesives, then the adhesive contains solvent requiring rapid bonding before evaporation, but hot-melt adhesives are generally solvent-free polymers
Solution Approach 1:
The invention fundamentally changes the adhesive formulation from solvent-based to moisture-curing polyurethane chemistry. This eliminates the harmful solvent evaporation issue while maintaining ease of application, as the adhesive cures through reaction with ambient moisture rather than requiring rapid bonding before solvent evaporation.
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 curable composition enables flexible and efficient bonding of polymer substrates with low tack and high peel strength, reducing the need for rapid assembly and minimizing storage requirements for small orders, while maintaining adhesive properties.
Implementation Method 1
A curable composition comprising a urethane (meth)acrylate oligomer, mono(meth)acrylate monomer, multifunctional crosslinking monomer, and ethylene-vinyl acetate grafted terpolymer, which forms a low-tack adhesive layer upon exposure to radiation or heat
Data Source
AI summary
Curable compositions include a urethane (meth)acrylate oligomer having a number—average molecular weight of at least 6000 g/mol; at least one mono(meth)acrylate monomer; a multifunctional crosslinking monomer chosen from acrylate monomers, methacrylate monomers, or combinations thereof; and an ethylene-vinyl acetate grafted terpolymer. The mono(meth)acrylate monomers may include a first mono(meth)acrylate with Tg between 50° C. and 175° C. and a second mono(meth)acrylate with Tg between −50° C. and 30° C. The curable compositions may be applied onto a surface of a substrate then cured to form a low-tack adhesive layer on the surface. The curable compositions may be cured by exposure to visible radiation, UV radiation, LED radiation, laser radiation, electron-beam radiation, peroxide, accelerator, or heat. Methods for bonding substrates include contacting a second substrate to a tow-tack adhesive layer on a first substrate, then heating the low-tack adhesive layer to bond the substrates and form a laminate.