Unwind Force of Tapes
Standard Test Methods for Pressure-Sensitive Adhesive-Coated Tapes Used for Electrical and Electronic Applications
ASTM D1000 covers several test methods for the characterization of tapes used in electrical applications. Several of the tensile and peel tests are already described in test procedures such as ASTM D903 and ASTM D3330. Therefore, this description will focus primarily on the unwind force test.
Pressure Sensitive Adhesive tapes are sold in rolls. In automated manufacturing environments, these rolls are loaded into a machine for assembly. The unwind force is an important specification because it may affect the machine behavior. Unwind force also plays a role in logistics environments where packages are being wrapped, taped and shipped off to their destination.
1 inch wide tapes are the typical size for testing a roll of tape. Wider samples can be used, however pressure sensitive adhesives which are wider than 1 inch may have more variability in the unwind force. At least 20 yards of tape must be on the test roll.
A motorized system must be used to unwind the tape, as demonstrated in the video. The speed of the unwind must be 150 ft/min. The top grip holds the roll of tape so that it can unwind freely and then spool onto the new roll which is attached to the motorized fixture.
The standard calculation for the unwind force is given in newtons per 10mm width of tape or ounces of force per inch width.