Shrinkage of PE films (Betex tester)
In-house method with Betex tester
Principle: A round specimen of plastic film with a diameter of 50 mm is placed on a heating plate, wetted with polyethylene glycol. The shrinkage takes place while the specimen is free "swimming" in the hot polyethylene glycol. Suitable e.g. for PE films, test parameters T = 150 ° C / t = 30 s, the shrinkage [%] is determined in machine and transversal direction.
Home method with Betex device
Principle: A film blank with a diameter of 50 mm is placed on a heating plate wetted with polyethylene glycol. Shrinkage takes place floating in the hot polyethylene glycol. Suitable e.g. for PE films; test parameter T = 150°C/ t = 30 s, the longitudinal and also the transverse shrinkage are determined in [%].
In short — AI-generated
This test determines the thermal shrinkage of PE films by placing a 50 mm circular specimen onto a heated plate covered in polyethylene glycol. The film shrinks while floating freely in the liquid at a defined temperature of 150 °C for 30 seconds.
The resulting values indicate the percentage of shrinkage in both the machine and transverse directions. This data helps packaging developers predict how a film will react to heat during processing or storage, ensuring dimensional stability in the final application.
Text is AI-generated; based on test method data curated and verified by Innoform.