Panasonic develops PBT laser welding compounds

Japanese electronics giant Panasonic Corporation (Osaka) is aggressively venturing into the automotive sector as further evidenced by a recent move to establish a car battery joint venture in China with Dalian Levear Electric that will commence operations next year. Panasonic also manufactures batteries for Tesla and is the automaker's partner for battery production in the forthcoming Gigafactory outside Sparks, Nevada, scheduled to begin cell production in 2017. By 2020, the Gigafactory will reach full capacity and produce more lithium ion batteries annually than were produced worldwide in 2013.

Panasonic is targeting ¥2.1 trillion ($18.5 billion) in sales for the automotive business overall, inclusive of infotainment systems and industrial devices in fiscal 2019, part of which will come from a somewhat unlikely source. The company announced this month that it will start mass production of polybutylene terephthalate (PBT) injection molding compounds for laser welding in March 2016, a move that will reportedly contribute to the enhancement of long-term reliability and the flexibility of design of automotive switches and sensors.

Currently, processing methods including sealing with packing and bolts, bonding with adhesives, and ultrasonic welding, are used for the production of automotive sensors. Laser welding, however, has recently attracted the auto industry's attention as its high welding strength can shorten the bonding time and increase productivity. However, Panasonic reports that existing plastic molding compounds generally used for laser welding possessed low laser transmittance, leading to problems with welding strength and watertight properties.

In order to address these issues, Panasonic has commercialized PBT molding compounds with the industry's highestlaser transmittance; 72% compared with 52% for the company's conventional products. Tests of parts molded using the compounds showed no air leaks under an air pressure of 3 atm in water after high temperature, high humidity storage and temperature cycling (-40?-100?) tests.

The hydrolysis resistance of the compounds is characterized by 94% retention of mechanical strength after 1,000 hours at a temperature of 85? and a humidity of 85% compared with 50% for the company's standard compounds. Further, warpage is typically one-quarter the level of standard PBT compounds.

The molding compounds will be on show at The LED Show (March 1-3, 2016, Santa Clara, CA) and the Highly-Functional Material World 2016 (April 6-8, 2016, Tokyo Big Sight).