No test has ever worn out a properly designed and molded hinge of homo-polymer
polypropylene. In most cases, the testing was simply terminated after approximately a million
flexes. One hinge unit molded of a 4 melt flow rate homopolymer was flexed at 75°F (23°C) over
a 180° angle 300,000 times, then at -20°F (-28°C) for another 300,000 cycles, and finally at
75°F for 300,000 cycles, all without failure.