Evaluating Surface Energy Decay in Thermal Polyurethane Film Lamination
Evaluating surface energy decay in thermal TPU lamination requires measuring polar force components to ensure bond strength before heat and pressure passes.
Thermoplastic Polyurethane
Elastomeric Coating
Advanced polymer resins combining the flexibility of rubber with the processing advantages of thermoplastics provide excellent abrasion resistance for specialty packaging. Extruding thermoplastic polyurethane onto a paperboard substrate creates a highly durable barrier layer that resists oils and solvents. It offers high tensile strength and puncture resistance while remaining heat-sealable.
Polymer Blocks
The molecular structure consists of alternating hard and soft segments that phase-separate into distinct domains. The soft segments, composed of long polyester or polyether chains, provide flexibility and low-temperature performance, while the hard diisocyanate segments act as physical cross-links that give the material its strength and elastic recovery. This phase separation allows the coating to stretch without rupturing, which protects the paperboard substrate from tearing under impact.
Adjusting the ratio of these blocks allows manufacturers to balance melt viscosity against the required flexibility and toughness of the final barrier layer.
Barrier Performance
Unlike standard polyethylene coatings, this polymer provides a superior barrier against chemical penetration and abrasive wear. It is co-extruded onto paper or board for applications that require tough, puncture-resistant surfaces, such as multi-wall sacks for industrial chemicals. The elastomer also maintains its flexibility at sub-zero temperatures, which makes it suitable for frozen food packaging.
Its high melt strength and rapid solidification allow for clean heat-sealing during bag converting.