The world market for pressure-sensitive adhesive tapes is expected to continue growing 5% per year through 2010 and be valued at $25 billion, according to the Freedonia study World Pressure Sensitive Tapes. Projected growth in tape production will generate demand for 3 billion kg of raw materials in 2010, including adhesives and various backing substrates. The growing global economy will create opportunities in developing countries like China and India, which will outpace the U.S. in terms of tape consumption. In addition, the cost and performance advantages of pressure-sensitive adhesive tapes will enable these products to capture an increasing share of the joining, sealing, and bonding market.
Satisfying the DemandPolymer films come in a variety of materials and forms, and are used in applications ranging from industrial and agricultural to the production of semiconductors and satellites. The worldwide demand for high-performance films is still experiencing strong growth.1 Technical demands are increasing all the time as application needs and customer requirements drive a demand for higher performance. Typical performance demands include the need for higher operating temperatures, improved abrasion resistance and increased chemical resistance. This often means that the choice of materials for tape substrates and films becomes restricted to a few high-performance engineering polymers. This particular segment of the high-performance engineering polymers market may be unfamiliar to engineers and designers.
Higher-performance engineering polymers can be defined as those that can operate above 200°C (392°F) on a long-term basis. Several polymer materials fall into this category, including VICTREX ®PEEKTM polymer, polytetrafluoroethylene (PTFE) and polyimide (PI). The PEEK polymer has comparable performance properties to PTFE and PI but provides some key combinations of properties not available in these materials.
The PEEK product is a linear aromatic semi-crystalline polymer. It has a high melting temperature of 343°C (649°F) and a glass-transition temperature of 143°C (289°F). The polymer combines this high-temperature performance with excellent chemical resistance, mechanical performance, high purity, electrical properties and good tribological behavior. It is used across many markets, from semiconductor manufacturing and electronics to automotive and industrial sectors.
PTFE was the first commercially available fluoropolymer, and has a melting point of 330°C (626°F). The polymer is highly crystalline and non-polar, which leads to very weak interactions between the polymer molecules. PTFE is a very low-friction material but is also very soft and prone to creep under mechanical load. PTFE has superb chemical resistance and is used in pipe and tank liners, valves, and laboratory equipment. It is also widely used in friction and wear applications across many industry segments.
Polyimide is an aromatic-based polymer with no glass transition or melting temperature prior to decomposition of the polymer. Most polyimides are classified as thermosets and are not melt-processable. The polymer displays a very linear change in mechanical properties with temperature over a full operating range. It also demonstrates excellent mechanical, electrical and chemical performance over a range of temperatures, and is used extensively in the semiconductor and electronics segment.
APTIV film features a range of properties that allow it to compete with polyimide and PTFE tapes as a high-performance tape backing material.
Compared to polyimide (PI), these films offer:
- Lower moisture absorption, which can adversely affect electrical properties and make parts susceptible to thermal shock.
- Excellent hydrolysis resistance when exposed to high-temperature-moisture environments.
- Chemical resistance - The film offers better performance in strong alkaline environments than polyimide.
- Abrasion resistance - The film provides improved resistance under abrasive loads.
- Physical, electrical and thermal aging properties that are comparable to polyimide.
- Increased tensile strength and modulus.
- Increased abrasion and creep resistance.
- Lower density than PTFE, resulting in weight reduction and efficiency savings.
Benefits of APTIV film tape backing include high-temperature performance; chemical and moisture resistance; excellent physical, mechanical and electrical properties up to 260°C (500°F); adhesion to difficult-to-bond-to substrates including polyimide and polyolefin; clean removability; and more. APTIV films are FDA-compliant and halogen free; as a thermoplastic, they are also recyclable and comply with RoHS. Capable of withstanding the higher processing temperatures required when using lead-free solders, APTIV film serves as an excellent masking material in electrical applications.
While both PTFE and polyimide will continue to be valuable options for use as tape substrates, APTIV film provides engineers with an alternative choice to PTFE or polyimide tapes. The development of these new substrates can also provide a potential source of product development and performance enhancement for the pressure-sensitive tape industry.
About the CompanyHeadquartered in the United Kingdom, Victrex plc is an innovative leading manufacturer of high-performance materials used in a variety of markets.
VICTREX® is a registered trademark of Victrex Manufacturing Limited. PEEKTM, PEEK-HTTM and APTIVTM are trademarks of Victrex plc. VICOTE® is a registered trademark of Victrex plc.
For more information on APTIV films, phone (800) VICTREX or visit www.victrex.com.
SIDEBAR: APTIV Film Performs in RFID TagsWhen O.T.A.-Bieletro, a Brazilian company specializing in solutions for identification and traceability, wanted a high-performance film for the encapsulation of its RFID tags used on a truck manufacturing line, it chose APTIV film based on VICTREX PEEK polymer. The film offers the ability to withstand the extreme temperatures encountered during the vehicle’s painting cycle without any loss in radio frequency signal reception capacity from the device.
Encapsulating the RFID tags with APTIV film protects small components from the aggressive environment of the truck’s production line and painting cycle. “This is a new application for us,” explained O.T.A. Director Xavier Landmarks. “The RFID labels encapsulated with the APTIV film performed beyond our expectations, withstanding more than 10 painting cycles. In addition, using the APTIV film allowed us to significantly reduce our costs.”
The RFID tag is a thin sensor that is 0.5mm thick. It is affixed on each truck chassis, where it remains for the entire production process. “The critical point in the process is the painting line, during which the truck is exposed to a very aggressive environment,” Landmarks said. “The challenge was to find a material that is resistant to painting cycle temperatures of 180°C, 200°C and 220°C (356°F, 392°F, and 428°F). The tags are exposed to each of these temperatures for one hour during the painting cycle. We needed a material capable of withstanding at least five of these cycles without any imperfections that might interfere with the readability of the labels.”
That material also required chemical resistance. “For example, it could not contaminate the painting tanks by releasing particles or gases that could contaminate the process,” Landmarks said. “It had to have low permeability and be able to thermally isolate the internal components.”
John Getz, commercial leader of APTIV Films, said, “APTIV film is extremely versatile and is used in a variety of high-performance automotive applications, including wear-resistant bearings, sensor membranes, gaskets, adhesive tapes, and now RFID devices. Its outstanding balance of chemical and wear resistance, and its ability to withstand extreme temperatures, makes APTIV films a leading choice for automotive-product designers.”