ASTM D429 Rubber Property - Adhesion to Rigid Substrates

ASTM D429 determines the adhesion strength of rubber to rigid materials, such as metals. The standard requires that the testing machine conform to practices described in ASTM E4. Our 3300 Series and 5900 Series universal testing systems meet this specification and provide an appropriate solution for this test application.

The standard calls out several test types related to rubber adhesion strength; however, Methods A and B are the most common.

• Method A describes a tension test used to determine the bond of a rubber part assembled between two parallel metal plates.  
• Method B describes a peel procedure to determine the adhesive strength between rubber materials to a metal plate or substrate. The value of interest is the "Adhesion Strength" defined as the maximum force divided by the width of the specimen.

The challenges of testing to this standard:

• Accurately tracking the peaks and troughs throughout the adhesion test in order to report precise results.
• Maintaining unidirectional force throughout the process of peeling from a substrate.
• Proper specimen gripping.

Our solutions:

• Bluehill Universal^® software can calculate adhesion strength values per this test method. Adjustable data acquisition rates allow the user to ensure they are capturing all the desired peaks and troughs throughout the entire test. (Methods A and B)
• We recommend using a 90° peel fixture that holds and moves the substrate as the rubber strip is peeled off by an upper grip. (Methods B)
• Pneumatic side action grips provide an appropriate solution due to ease of use, productivity, and better repeatability. Pneumatic grips also provide constant clamping force throughout the test to avoid specimen slippage. Manual screw action grips can also provide an adequate and affordable solution for this test. (Method B)

It is important to review ASTM D429 in order to fully understand the test setup, procedure, and results requirements.