A strong bond
Attention molders: Covestro high-heat polycarbonate an ideal choice for silicone overmolding
At NPE® 2018, Momentive will form phone stands by overmolding Apec® 1745 high-heat polycarbonate from Covestro with its Silopren LSR 4749. (Photo credit: © Momentive Performance Materials Inc.)
Pittsburgh, May 7, 2018 - Soft-hard design calls for multi-component processes with good adhesion performance between silicone elastomers and thermoplastics. Despite advances in adhesion technology, it is still difficult to meet adhesion requirements—even when a primer is applied. To solve these challenges, Momentive launched Silopren* LSR 4749—a self-bonding liquid silicone rubber (LSR) that offers primerless adhesion to a wide range of substrates.
At NPE® 2018, May 7-11 in Orlando, Florida, attendees can see how LSR is used in conjunction with Covestro polycarbonate. At booth S29085, Momentive will hold a molding demonstration for phone stands using Apec® 1745 high-heat polycarbonate from Covestro overmolded with self-bonding Silopren LSR 4749. This polycarbonate material can withstand higher temperatures, making it an ideal choice for the silicone overmolding process.
“Apec® 1745 polycarbonate demonstrates excellent adhesion to our self-bonding Silopren LSR 4749,” said Chris Claussen, global marketing director for healthcare, Momentive. “With a high-heat stability, this grade allows for LSR overmolding at higher temperatures with much shorter cycle times.”
“Out of all material options, this high-heat polycarbonate offers the best combination of adhesion and high-heat resistance to assure the fastest possible curing time for Momentive’s self-bonding LSR,” said Pierre Moulinie, global technology lead, Medical and Consumer Products – Polycarbonates, Covestro. “In fact, it reduces curing times by up to 50 percent and leads to lower production costs when compared to standard polycarbonate.”
Apec® 1745 polycarbonate is a medical grade that features outstanding clarity and is appropriate for repeated steam sterilization up to 143° C. It can be used for several health care applications that require a soft edge or surface, such as respiratory masks, soft touch tips and applications that require gaskets.
“We always evaluate each application to determine which polycarbonate material is right for the job,” said Lauren Zetts, North America market manager, Medical and Consumer Products – Polycarbonates, Covestro. “For the silicone overmolding process, our high-heat polycarbonate has what it takes.”
Apec® 1745 polycarbonate and Silopren LSR 4749 are both globally available.