Physical Properties of Medical Adhesives from Segmented Poly (urethane) s

The surface tension of SPUA's [segmented poly (ether-urethane) adhesives] was evaluated to be approximately 30dyn/cm. Their peel strength for the surface of plastics with different surface tensions was high when the block copolymer-homopolymer (B-H) combination (M-PEG/P-OH=3/2mol. ratio, OH/NCO=1.20) was used as the polyol and isocyanate component segments of SPUA, in comparison with the strength observed when the random copolymer-random copolymer (R-R) combination (M-PEG/P-OH= 3/2mol. ratio, OH/NCO=1.05) was used. However, the peel strength for human skin was higher for R-R than for B-H. The peel strength of the R-R for human skin was initially as high as 250g/2.5cm and 200g/2.5 cm after 10 times repeated patching and peeling. The high peel strength of R-R for human skin seems to be caused by their low cohesive force and flexibility. As SPUA's are excellent in water resistance and shape retention, the surface adhesion could be revitalized after repeated washing with water. SPUA's caused minor irritation to human skin.