Comparative Properties of Thermoplastic Polyurethane Adhesive Filled with Natural or Precipitated Calcium Carbonate

Abstract

Abstract Summary: The rheological, mechanical and adhesion properties of thermoplastic polyurethane adhesive (TPU) containing natural ultramicronized or precipitated nanometric calcium carbonate filler were compared. Precipitated calcium carbonate addition did not noticeably improve the rheological properties of filled TPU with respect to the effect produced by adding natural calcium carbonate. The precipitated calcium carbonate nanoparticles migrated to the TPU surface due to incompatibility between the filler and the polyurethane. The wettability of the filled TPU was reduced by adding natural calcium carbonate, but it was increased slightly by adding precipitated calcium carbonate. Finally, the immediate adhesive strength in PVC/TPU adhesive/PVC joints increased noticeably when the adhesive contained filler; however, the final adhesive strength was similar irrespective of the filler particle size.