Chemicals company Sabic (Houston, TX) has introduced a new line of high-clarity, high-heat, injection moldable polycarbonate copolymer resins. Lexan CXT resins can offer a unique balance of high temperature resistance, high flow and color stability under extreme molding conditions, together with a high refractive index, according to the company.
The resins are suited for use in optical applications in the electronics, consumer and industrial, and healthcare industries. Typical products include lenses and small sensors that detect visible light; in healthcare applications, the materials’ optical quality and temperature resistance make them good candidates for over-molding clear face shields with silicone rubber.
With Vicat B120 softening temperatures as high as 190°C and glass transition temperatures (Tg) up to 195°C, Lexan CXT resins can provide converters with the potential to injection mold parts that withstand demanding assembly processes, such as cold reflow or wave soldering onto printed circuit boards. Parts will also stand up to prolonged exposure to high service temperatures.
Featuring a refractive index (RI) over 1.6 as well as transparency greater than 89% in the visible and infrared spectra at a thickness of 1 mm, the resins can help enable the production of very small lenses (such as those used in mobile phones) that can be assembled onto a PCB that then goes through various soldering operations. The material’s thermal stability can help prevent deformation or discoloration.
Feedback from Sabic customers over the course of the development of Lexan CXT resins indicates numerous other potential benefits. These include improvements in productivity and system costs through shorter cycle times; improved dimensional accuracy; fewer production stoppages and lower reject levels; and the potential to create components with more complex geometries, thinner and longer walls, and improved textural definition.
The new resins will complement existing Lexan polycarbonate copolymer specialty resins, which include EXL, XHT and SLX resins. These can be distinguished, respectively, by particularly good low-temperature impact resistance, heat resistance in clear and opaque forms, and high weatherability.