What is pressure-sensitive tape?
Tape that has a backing that’s coated with an adhesive on one or both sides. In the case of a double-sided tape, a release liner would be used to prevent the roll of tape from adhering to itself.
What are the different components of a tape?
- Backing: A thin, flexible material that can be coated with adhesive. Can be made of paper, fabric, film foam, foil, laminate or non-woven material.
- Adhesive: Types include natural or synthetic rubber, acrylic and silicones.
- Primer: Used to increase the bond of the adhesive to the backing. Assists in keeping the adhesive on the backing when a tape is removed.
- Release Liner: Usually used for double-sided tapes. Sometimes found on single-sided tapes as well. Siliconized paper is the main type of release liner. Siliconized film is also used in applications requiring greater flexibility and high-tensile strength.
- Release Coating: Applied to the backing. Allows the tape to unwind from the roll. Without a release coating, the tape would adhere to its own backing and wouldn’t unwind.
How is tape applied?
Pressure-sensitive tapes require pressure to ensure bonding. (For example: masking tape needs your finger or hand to secure it to a surface.) For maximum adhesion, even pressure should be applied. Bonding should take place at a moderate temperature (68-72 degrees F, 20-22 degrees C). Note that acrylic tapes don’t typically achieve their maximum adhesion until after 72 hours of dwell time. Some tapes may even take up to 7-15 days due to the high level of adhesive cross-linking.
- Bonding to Low Surface Energy Surfaces: For hard-to-stick-to surfaces, such as Teflon, silicone or polyethylene, you can increase the adhesive strength by pre-treating the surface with a method specifically sited to the material in question.
- Bonding to High Surface Energy Surfaces: With easy-to-stick-to surfaces, sometimes additives can migrate to the surface in get in the way of the adhesive. Therefore, it is recommended that a compatibility test be done ahead of time.
- Bonding to Metal Surfaces: Check first on non-ferrous metals (i.e., lead, copper, brass and nickel) before adhering tape. A chemical reaction could occur and alter the surface polarity.
How should surfaces be prepared?
For optimal adhesion, surfaces must be clean, dry and grease, oil and lint-free. Try cleaning with esters (like ethyl acetate or acetone), ketones (like MEK) or naptha-based products.
How should pressure-sensitive tapes be stored?
To retain their properties while in storage, pressure-sensitive tapes should be kept in the following conditions:
- 68-72 degrees F, 20-22 degrees C
- 50% relative humidity
- Rolls should be stored flat in their original packaging and away from direct sources of UV light
- Logs and spooled rolls should be stored to prevent distortion.
What are common tests or properties of pressure-sensitive tapes?
- Adhesion: Tests the strength of the bond between a tape and the application surface.
- Cohesion: Tests the internal strength of an adhesive.
- Shear: Tests the ability of an adhesive to resist slippage or creep.
- Tensile Strength: Tests the force or load needed to break a tape.
- Elongation: Tests how much stretching a tape can endure before it breaks.
- Thickness: Determines the distance between the two opposite surfaces of the whole tape.