ASTM D3330 Peel Adhesion Testing of Pressure Sensitive Adhesive Tapes

ASTM D3330 is a major peel testing standard that outlines the requirements for determining the peel adhesion properties of pressure-sensitive tapes such as surgical, electrical, packing, and duct tape. The standard includes 6 different methods (A-F) for measuring peel adhesion with both 90° and 180° peel tests. This guide is designed to introduce you to the basic elements of ASTM D3330 testing, including an overview of the equipment, software, and specimens needed. 

Specimen Conditioning

• The rolls of tape to be tested must be conditioned per ASTM D4332 for at least 24 hours.
• The tape is applied to a 302 or 304 stainless steel panel that is 50 X 125 mm and at least 1.1 mm thick. The surface roughness of the panel should be 50 ± 25 nm. The panel should be in pristine condition, with no scratches, stains, or discoloration.
• The 24mm (1 inch) side tape specimen is cut to a length of 300 mm and then fixed to the steel panel using a mechanically or hand operated roller to assure even and repeatable pressure during application.
• Each specimen should be prepared and tested within one minute. The adhesion properties will increase with a longer dwell time, so it’s critical to maintain a consistent dwell time to minimize variability in results. It’s also important to note that heat can be transferred through the steel panel to the specimen, so handling of the panel should be kept to a minimum.

Materials Testing System

Peel tests require a high data acquisition rate to record the peaks and troughs during the test. An Instron 6800 Series testing system, which has a maximum data acquisition rate of 5kHz, is recommended. A single column test frame, available in capacities up to 5kN, is sufficient for most D3330 applications; however, testing can be performed on a higher capacity system if additional force is required. Bluehill Universal includes peel test method templates and calculations, making it easy to create and modify test methods and to include the peel adhesion value in the test report.

Fixtures

180° peel testing, as outlined in Methods A-E, requires grips to secure both the tape under test and the attached substrate to the universal testing machine. Pneumatic side-action grips are recommended because maintain a constant pressure on the specimen throughout testing. A foot switch is used to open and close the grips, leaving the operator’s hand free to handle and align the specimen. Both grips can be used with a variety of jaw faces in different sizes and surfaces (serrated, rubber, or smooth) to accommodate different materials. Advanced screw side action grips are also commonly used grips for testing to ASTM D3300.

90° peel testing per Method F requires a specialized fixture. The 2850-035 peel fixture has a t-slot sled to which the steel plate is attached. The loose end of the specimen is inserted into the grip. As the crosshead applies tensile force, the cable pulls the sled laterally along the guide rail to maintain a constant 90° angle of peel. This prevents any exertion of outside forces on the specimen.

Test Setup

All six of the test methods within ASTM D3330 are run with a rate of 5.0 ± 0.2 mm/s rate. The system requires accuracy of 0.5% of full scale and the mean test level should fall within 20 to 80% of the full scale of the load cell. Though the peel test is performed in the same manner in Methods A-E, there are some differences in how the specimen is set up for each test:

• Method A: The tape is applied to the steel panel. The free end is inserted into the grip and peeled directly from the steel panel.
• Method B: A strip of tape is applied to the steel panel. A second strip of tape is applied to the backing of the first strip of tape, before being peeled off.
• Method C: Both the face and linear sides of the tape are peeled from the panel, using a strip of 0.025 mm thick polyester film as backing.
• Method D: After the tape has been applied to the steel panel, the liner is separated from the tape and inserted into the grip. The test peels the liner from the tape.
• Method E: Both the face and linear sides of the tape are peeled from the panel, using a strip of 0.025 mm thick polyester film as backing.
• Method F: The tape is applied to the steel panel, which is secured to the 90° peel fixture. The free end of the tape is inserted into the grip and peeled directly from the steel panel. 

Results

Data should be collected at least once per 1.0 mm of tape peeled. The data that is collected during the first 25 mm of testing should not be used for any result calculations. Instead, divide the average force during the peeling of the next 50 mm of tape by the specimen width to calculate the peel adhesion value. The test report should include the peel adhesion value, identification of the test method used, dwell time, specimen width, and test conditions (temperature/humidity). For more information about ASTM D3330, purchase the standard.