EVOH Barrier Measurement
EVOH (Ethylene vinyl alcohol ) barrier layer detection is quite a challenge, especially if you don’t want to cut the device under test for a time consuming visual inspection under the microscope. Ultrasound can pass through a multi-layer plastic container wall and analyze the EVOH layer for barrier presence and layer thickness.
Background
The walls of plastic fuel tanks consists of 5 or more layers. One of which, is being used to reduce HC-emission. This is often done with a thin Ethylene vinyl alcohol (EVOH) layer. Measuring the thickness of this layer is a crucial factor of fuel tank quality assurance.
A common, but time consuming and destructive method to measure layer thickness is to cut out samples from a fuel tank wall. The samples have to be prepared for measurement by microscope.
The Challenge
Ultrasonic measurement of thin layers (<100µm) requires the use high frequencies, but plastic (HDPE) has a very high attenuation for high frequencies. There is no signal left after travelling thru a 8mm thick PFT wall.
Solution
Our ultrasonic measurement system is an invaluable tool for EVOH layer thickness gauging in PFT. The device is able to measure EVOH layers 40-50 µm
Specifications
Total wall thickness: 2-8mm
EVOH-thickness: 50-250µm
Accuracy: +/-10µm at 3% EVOH layer
Your advantages
- Non-destructive measurement of EVOH layer thickness
- Fast measurement for measurement of many different points
- Integrated documentation of measurements
- Operator assistant for points to be measured (option)
- Option: barcode scanner interface
Applications
- Pesticide plastic bottles
- Food packaging
- IBC container
