Testing Methods and Precautions for Low Barrier Property Materials on OX2/231

OX2/231, the equal pressure film and package permeability tester, applies the consumable coulometric sensor as the core of the instrument. When testing on specimens with oxygen transmission rate higher than 2000, a series of protective measures for the instruments should be carried out. Hereinafter, we would mainly discuss on the testing method and precautions for low barrier property materials, so as to guarantee testing accuracy and prolong instrument life.
1. Testing Methods
1.1 Select Testing Mode
This instrument has three testing chambers, and can test three specimens with average value.
However, as to high transmission rate specimens, a test of one of two chambers is preferable. The reason is that when testing in three chambers simultaneously, the oxygen concentration transmitted to the sensor is so high that sensor overload or reduced sensor life would be caused.
1.2 To Change Air as the Testing Gas
This instrument installs oxygen sensor, and oxygen is the testing gas for most of the time. Yet, when the barrier property is low and the transmission quantity is great, air can also be used for testing. Since 20.9% oxygen exists in the air, a conversion would bring the transmission quantity in pure oxygen condition approximately. Thus, testing range is widened.
1.3 To Change Flow
When in operation, the flow quantity in lower chamber is about 10ml. When testing low barrier materials, we can increase the flow quantity properly to dilute the transmitted oxygen quantity so as to lower the damage of high oxygen concentration to the sensor.
1.4 To Select MASK
MASK is used to reduce testing area of the specimens so as to reduce the transmitted oxygen concentration into the sensor and enlarge testing range.
2. Precautions
2.1 The Observation at the Beginning of Test
The test formally starts when oxygen is purged into the instrument from the upper chamber. The operator should pay special attention to the changes of oxygen transmission quantity. Great amount of oxygen would come to the sensor caused by leakage of inferior specimen clamping or over-high transmission quantity through the specimen. The operator should timely handle the issue so as to avoid damage to the sensor.
2.2 Procedures after Tests
After every test, sensor would still in the high oxygen condition. Thus, oxygen of upper chamber should be closed, and nitrogen should be purged to guarantee low oxygen condition for the sensor when not in operation, so as to prolong the life of the sensor.