Strength and Ultrasonic Testing of Acrylic Foam Adhesive Tape

Abstract

Adhesive joints are some of the oldest inseparable connections, and were used much earlier than other non-separable connections (e.g., welded, soldered). Adhesives are widely used in the manufacture of vehicles, household appliances, aircraft, and medicine. One disadvantage of adhesive joints is their long bonding time (amounting, for example, to 72 h for polyurethane adhesives used in bus roof bonding), and another is their production of harmful waste. Tapes that are adhesive coated on both sides are increasingly being used to join parts during production. Such tapes have lower strength than traditional adhesives, but their bonding time is much shorter. In addition, the amount of waste remaining after production is minimized. Tapes, like adhesives, dampen vibrations well and seal the materials being joined. The purpose of this study was to evaluate the influence of selected factors on the quality of tape–steel sheet joints and to assess the possibility of testing acrylic tape–steel sheet joints using ultrasonic methods. It was found that the preparation of a surface for bonding has a significant effect on the quality of the joint, and it was confirmed that non-destructive evaluation of the quality of the tested joints by the ultrasonic method is possible. The decibel drop in the height of the first and fifth pulses obtained on the screen of the ultrasonic defectoscope was proposed as an ultrasonic measure. The highest-quality joints were characterized by a measure in the range of 12 dB, lower-quality areas of about 8 dB, and tape-free areas of about 5 dB. At the same time, it was noted that in the case of proper surface preparation, there was cohesive failure of the joint during breakage.