Moisture Barrier Property Test of UV Light Curing Adhesive

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UV curing adhesive is one kind of adhesive, where the ultraviolet light and visible light is used to initiate a photochemical reaction that promotes the curing of adhesive. UV curing adhesive is featured with fast and simplified curing process, energy-saving and easy-to-use and many other advantages, which is suitable for production of crafts, glass wares, PCB, optic fiber and medical devices parts, etc.

Moisture barrier property is quite important for UV curing adhesive. For example, the electronic products are very sensitive to the water vapor. If the UV curing adhesive used in encapsulation is poor in moisture barrier property, the water vapor in ambient environment may permeate into the internal section of electronic parts and the service life of those electronic products may be reduced remarkably. To some extent, the water vapor transmission rate of UV curing adhesive used in encapsulation decides the service life of electronic products. For the reasons mentioned above, it is necessary to test the UV curing adhesive before use.

This article provides a test method of water vapor transmission rate of UV curing adhesive for your reference. The testing instrument we used for the tests is Labthink’s W3/030 Water Vapor Transmission Rate Tester.

Currently there are mainly two categories of test methods for water vapor transmission rate i.e. gravimetric method (also known as cup method and divided into dry cup method and wet cup method) and sensor method (including electrolytic sensor method, infrared sensor method and humidity sensor method). Labthink W3/030 Water Vapor Transmission Rate Tester adopts gravimetric method.

Figure 1. W3/030 Water Vapor Transmission Rate Tester

We tested UV curing adhesive sample provided by one adhesive manufacturer in the following procedures.

1. Make Specimens

Make liquid UV adhesive into thin layer of sheet with uniform thickness. Then cut three pieces of specimens from the sheet with sample cutter. The diameter of those specimens should be 74mm.

1. Mount Specimens

Clamp the three pieces of specimens on the three test dishes respectively. Those test dishes are filled with certain amount of distilled water. Then place the dishes on the dish supports and then close the door of the instrument.

Figure 2. Mount Specimen

1. Start Tests

Set specimen thickness, test temperature, humidity, test mode and other parameters. Then click Start Test to start the tests. The instrument will weigh the test dishes according to the preset settings and finally calculate and display the test results automatically.

1. Finish Tests

When the tests are finished, the instrument will display the test results automatically.

For more details about W3/031 Water Vapor Transmission Rate Tester, please visit www.labthink.com