01-08-2008, 04:43 AM
Many plastic bottle caps are a different type of plastic (not just a sturdier formula, but a completely different type - usually a more flexible type, than the bottle because of the different forces that the cap must endure (remember forces, wedges & such from school, the cap must be able to withstand wedge forces).... When you keep the cap on, you are creating a mixed plastic, and there is currently very little - no market for mixed plastics.
Most clear plastic bottles are 1 - PETE that has good pressure resistance, but could crack as a cap.
Most clear plastic bottles are 1 - PETE that has good pressure resistance, but could crack as a cap.