Polyurethane Acrylic Hot-Melt Adhesive Residual Monomer Control
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Solution Overview
Problem
Hot-melt pressure-sensitive adhesive (HMPSA) compositions based on polyurethane/(meth)acrylics face challenges due to residual diisocyanate and (meth)acrylic monomers, which can be toxic and require additional safety measures, limiting their industrial application and compliance with regulatory thresholds.
Innovation Solution
A HMPSA composition comprising polyurethane with specific end functional groups, a tackifying resin, and a polymerization inhibitor, formulated to minimize residual monomers, ensuring a polyurethane:tackifying resin ratio of 4:6 to 6:4 and a mean functionality greater than 1.9, thereby reducing toxic content below regulatory limits while maintaining adhesive properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polyurethane/(meth)acrylic HMPSA compositions are used to achieve strong adhesive properties, then adhesive strength is improved, but residual diisocyanate and (meth)acrylic monomers increase toxicity and regulatory non-compliance
Solution Approach 1:
The patent removes harmful residual monomers (diisocyanate and (meth)acrylic monomers) from the adhesive composition through optimized formulation and controlled synthesis, extracting only the necessary functional components while eliminating toxic byproducts that violate regulatory thresholds
Solution Approach 2:
The patent changes the chemical parameters of the adhesive system by using specific polyurethane formulations with controlled molecular weight and functionality, along with optimized ratios of components, to reduce residual monomer content below regulatory thresholds while preserving adhesive performance
2Reliability
If additional safety measures are implemented to handle residual monomers, then safety is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent implements safety by preliminary action through optimized formulation design that prevents excessive residual monomer formation from the outset, rather than requiring additional safety equipment or procedures to handle harmful substances after production
3Strength
If polyurethane:tackifying resin ratio is optimized to 4:6 to 6:4, then adhesive properties are maintained, but formulation precision requirements increase
Solution Approach 1:
The patent establishes an optimized parameter range for the polyurethane:tackifying resin ratio (4:6 to 6:4) that provides a balance between adhesive performance and manufacturing feasibility, allowing sufficient tolerance while maintaining strong adhesive properties
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 formulation achieves reduced content of residual monomers, enhancing safety and compliance while maintaining strong adhesive properties and temperature resistance, suitable for industrial applications.
Implementation Method 1
at least one polymerization inhibitor; the said composition being characterized in that: the polyurethane(s) (a): tackifying resin(s) (b) ratio by weight ranges from 4:6 to 6:4
Data Source
AI summary
A hot-melt pressure-sensitive adhesive composition comprises:a) at least one polyurethane comprising at least two end functional groups T of following formula (I):—X—(C═O)—CH(RV)═CH2 (I)b) at least one tackifying resin chosen from the following resins:(b1) terpene/phenolic resins;(b2) the resins resulting from the polymerization of α-methylstyrene, optionally followed by a reaction with at least one phenol;(b3) the polymeric resins (optionally at least partially hydrogenated) resulting from mainly C9 aromatic fractions; andc) at least one polymerization inhibitor.The polyurethane(s) (a): tackifying resin(s) (b) ratio by weight ranges from 4:6 to 6:4. The said polyurethane (a) has a mean functionality of functional groups of formula (I) strictly of greater than 1.9.