Polycarbonate is the ideal lens material for corrective eyeglasses and sunglasses due to its light weight, impact resistance, durability and comfort. However, not all polycarbonate for eyewear applications is created equal. Lens-quality grades of Makrolon® polycarbonate from Covestro offer excellent optical properties, high mechanical strength, comfort and toughness.
When original equipment manufacturer Jiangsu Sigo Optical Co., Ltd. (“Jiangsu Sigo Optical”) decided to upgrade the polycarbonate material used for its corrective and sunglass lenses, it turned to Makrolon® polycarbonate resin for improved optical purity and production yield.
For corrective lenses, Jiangsu Sigo Optical utilized Makrolon® DP1-1821 polycarbonate, which is formulated specifically for the optical/ophthalmic market. Available in clear tints, the material offers a number of advantages for corrective lenses including:
- High optical purity, transmission and scatter resistance
- UV stabilized
- High viscosity and easy release from the mold
For outdoor sports and activities, sunglasses provide UV protection, impact-resistance and style. Makrolon® LQ2887 polycarbonate, a new optical grade, is used for high-performance sunglass lenses from Jiangsu Sigo Optical.
Protecting eyes from UV rays is important. Makrolon® LQ2887 polycarbonate provides UV protection from wavelengths up to 400 nanometers (nm), which blocks both UVA and UVB rays, allowing the sunglasses to be labeled as UV 400 cut.
Furthermore, this material:
- Offers thin and fashionable design combined with impact resistance, and is appropriate for outdoor sports such as mountain biking and beach volleyball
- Is appropriate for beach and snow environments where water and snow reflect harmful UV rays
- Offers medium viscosity and easy release from the mold
In addition to supplying the materials, Covestro also offered valuable technical assistance.
“Our ophthalmic lens branded as Sigo+ meets the global market’s quality requirements with stable growth in export sales, thanks to the high productivity and low impurity quality of Makrolon® polycarbonate from Covestro,” explains Liu Jianzhong, General Manager, Jiangsu Sigo Optical Co., Ltd. “The project team had Covestro’s full support, which helped them scale up the new material on production lines just in three months.”
The successful product launch was also noted by Marina Lee, senior marketing manager, Medical and Consumer Products – Polycarbonates, Asia Pacific, Covestro (Shanghai) Management Co., Ltd. “We worked closely with Jiangsu Sigo Optical and provided on-site technical support to ensure the process of qualifying the high-quality Covestro materials went smoothly. As a result, the use of Makrolon® LQ2887 polycarbonate in the sunglass lenses provides outstanding UV performance with protection to 400 nm,” she explained.
Attendees at the 32nd International Exhibition on Plastics and Rubber Industries (CHINAPLAS 2018), April 24-27, in Shanghai, China, can visit the Covestro booth (Hall 7.2 D41) for more information about the company’s medical applications and materials.