Characterization of polyurethane foam as heat seal coating in medical pouch packaging application

In this study the use of polyurethane foam (PUF) as a heat seal coating for potential application in medical pouch packaging were investigated. We prepared PUF coatings at various foam densities and cell densities through mechanical foaming at various stirring speeds; then used a LUMisizer to examine their stabilities. After applying PUF coatings of various foam densities onto a medical packaging material (Tyvek (R)) at various thicknesses, then employed impulse heat sealing with linear low density polyethylene (LLDPE) films to fabricate medical pouches. In addition to investigating the morphology, tack properties, adhesion, scratch resistance, flexibility, and durability of the PUF coats, the peel strength and air permeability of the medical pouches were also measured. Increasing the foam density of the PUF coatings increased their stability; the PUF coats prepared at a higher foam density exhibited greater tackiness (<1 g/cm(2)), adhesion (5B), scratch resistance (HB), flexibility (passes), and durability (Delta YI <= 5). The peel strength measured in the T-peel configuration increased upon increasing the foam density and decreasing the coating thickness of the PUF coat/LLDPE pouches. The air permeability of the pouches increased upon increasing the foam density and cell density of the PUF coat/LLDPE pouches. Morphological studies using scanning electron microscopy were consistent with the experimental results.