When it comes to testing adhesives, there are several different tests that can be used to determine the strength of the bond. These include Dyne tests, Loop tack tests, Static shear tests, and QUV tests. To increase the test value, both surfaces should be properly prepared. Blasting the surfaces prior to testing them can produce better results than sanded surfaces.
Dyne tests
Dyne tests are a method of assessing the adhesion of a substance to another material. They are typically used in packaging applications to determine whether a material can be bonded with a standard packaging hot melt. If a material’s dyne level is 40 or above, it can usually be bonded using a standard packaging hot melt. If the dyne level is between 38 and 40, a specialty packaging adhesive may be required.
Loop tack
The Loop Tack test is used to determine the adhesive strength of pressure-sensitive tapes and labels. It is a highly accurate and standardized way of testing adhesive strength. The device is easy to operate and includes an ergonomic design. It is also able to test a wide range of adhesive samples.
Static shear
Static shear for adhesive testing involves pulling the two ends of a sample apart at a controlled rate. The force applied is proportional to the total adhesive surface area.
QUV tests
QUV tests simulate the effects of exposure to the sun and moisture on materials. The QUV accelerated weathering tester reproduces conditions that could cause damage over months or years outdoors. It uses fluorescent lamps to generate UV light and a heating system to maintain a controlled temperature. It also provides moisture via forced condensation.
Dolly preparation
Dolly preparation is an important part of the adhesive testing process. It ensures a strong bond at the dolly-adhesive interface and maximizes the repeatability of pull-off adhesion testing. Pull-off adhesion testing involves applying a force to a coating to pull it away from its substrate. By removing any potential sources of variation, the results of the adhesive testing can be more meaningful.
Effects of deviation from required method
A deviation from the required adhesive testing method can affect the final adhesion value of a coating. Minor differences in test steps, such as the adhesive used or the method of surface preparation, can affect the test result. It is also important to ensure that the testing methods are consistent, so that the results of different adhesives can be compared.
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