The Loop Stiffness Tester™ is a compact testing machine used to evaluate the flexibility or rigidity of very thin plastic film, copper foil etc.

When a specimen is set, it is automatically deformed into a “loop” shape and the compression resistance of the loop is measured by the load cell.

In the case of evaluating the “stiffness” of thin specimens such as magnetic tape and plastic film, many conventional measurement methods are affected by the self-weight of the specimen itself, making evaluation difficult.

The Loop Stiffness Tester minimizes these difficulties by bending the specimen into a loop shape, fixing it in a direction that is less prone to sagging under its own weight, and the “stiffness” of the specimen is evaluated by the load applied when the diameter direction of the loop is crushed.

This method enables evaluation of minute differences compared to the conventional method.

The measurement method is unique to Toyoseiki and was originally developed to evaluate the flexibility of magnetic tape.

Although this method is not standardized and differs from ISO and other testing standards, it is widely used to evaluate the stiffness of copper foils for FPC (Flexible Printed Circuits).