Plastic wrap, is a thin plastic film typically used for sealing food items in containers to keep them fresh over a longer period of time. The plastic wrap can be classified into different types by the materials used and plasticizer added. Different types of plastic wrap can be used for applications.

No. 1, PE film, the plastic wrap made of such material is widely used to pack food such as fresh fruits, vegetables and semi-finished cooked food sold in supermarket. Such plastic wrap can be used widely because it is applicable to food containing large amount of oil and can be heated in microwave oven below 110℃.

No. 2, PVC film, the plastic wrap made of PVC can be used for food packaging, but it may cause harm to the human health.

No. 3, PVDC film, the plastic wrap made of PVDC is mainly used for cooked food e.g. ham.

Among the three types of plastic wraps, PE and PVDC films are safe to use, while PVC film contains the substances that may cause cancer so it is harmful to human health. Therefore, PE film is usually the first choice of plastic wrap. This article discusses the oxygen barrier property of PE film which plays a great role in efficacy of fresh-keeping of food. Generally, the higher the oxygen barrier property is, the better the fresh-keeping performance of PE film is.

This article provides a simplified oxygen barrier property test method of PE film as plastic wrap for your reference. The testing instrument is Labthink’s C130H Gas Permeability Tester, which adopts differential pressure method.

With differential pressure method, the sample is mounted in a gas transmission cell so as to form a sealed semi-barrier between two chambers. One chamber contains the test gas at a specific high pressure, and the other chamber, at a lower pressure, receives the oxygen. The oxygen will be detected by either a manometric sensor or a volumetric sensor.

Figure 1. Plastic Wrap made of PE

Figure 2. C130H Gas Permeability Tester

The tests can be performed according to the following procedures.

(1)   Cut three pieces of specimens with sample cutter. The diameter of the specimen should be Φ97 mm.

(2)   Clamp the three specimens into the test cells of the instrument.

(3)   Set specimen name, specimen thickness, test temperature, test humidity and other test parameters.

(4)   Switch on the vacuum pump.

(5)   Click Start Test to start the tests. The test results will be calculated and displayed automatically.

By testing the oxygen barrier property, the manufacturer can select proper packaging materials to ensure the quality of their products within shelf life.

For more details about C130H Gas Permeability Tester, please visit www.labthink.com

About Labthink Instruments Co., Ltd:

Labthink Instruments Co., Ltd is one leading supplier of packaging testing instruments, which is headquartered in Jinan, China and operated in Boston, U.S.A.