A versatile plastic for glasses

Lens manufacturer Jiangsu Sigo Optical relies on polycarbonate from Covestro
Polycarbonate is an ideal lens material for corrective eyeglasses and sunglasses: It is lightweight, impact resistant, durable and comfortable. However, not all polycarbonate for eyewear applications is created equal. Covestro has developed special lens-quality grades of its Makrolon® polycarbonate which are characterized by excellent optical properties, high mechanical strength, toughness and comfort.

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 Covestro Makrolon® polycarbonate resins for improved optical purity and production yield.

High optical purity grade
For corrective lenses, Jiangsu Sigo Optical utilizes Makrolon® DP1-1821 polycarbonate, which is formulated specifically for the ophthalmic market. Available in clear tints, the material offers a number of advantages for corrective lenses including high optical purity, transmission and scatter resistance and UV stabilization. In processing, the material is distinguished by its high viscosity and easy release from the mold.

For outdoor 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. The abbreviation “LQ” stands for “lens quality”.

UV protection included
Importantly, Makrolon® LQ2887 polycarbonate provides UV protection from wavelengths up to 400 nanometers (nm), which blocks both energy-rich UVA and UVB rays. The product offers thin and fashionable, yet impact resistant lenses, and is appropriate for outdoor sports such as mountain biking and beach volleyball. UV protection is especially effective in beach and snow environments where water and snow strongly reflect harmful UV rays.

Owing to its medium viscosity and easy release from the mold, the product is easy to process. In addition to supplying the materials, Covestro also offers valuable technical assistance.

Rapid scale-up of a new product
“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 nanometers,” she explained.

Attendees at the 32nd International Exhibition on Plastics and Rubber Industries (CHINAPLAS 2018), April 24-27, in Shanghai, China, will receive more information about Covestro´s medical applications and materials in Hall 7.2, Booth no. D41.

About Covestro:
With 2017 sales of EUR 14.1 billion, Covestro is among the world’s largest polymer companies. Business activities are focused on the manufacture of high-tech polymer materials and the development of innovative solutions for products used in many areas of daily life. The main segments served are the automotive, construction, wood processing and furniture, and electrical and electronics industries. Other sectors include sports and leisure, cosmetics, health and the chemical industry itself. Covestro has 30 production sites worldwide and employs approximately 16,200 people (calculated as full-time equivalents) at the end of 2017.

About Sigo:
Jiangsu Sigo Optical Co., Ltd. was founded in 1998. Its factory locates in Danyang, which is the base of lens manufacture in China, mainly engages in manufacturing and selling all kinds of resin lenses, such as single vision lenses, tinted lenses, bifocal lenses, photochromic lenses, semi-finished lenses and so on. Meanwhile, more and more new types will be introduced into worldwide market continuously. Since 2005, its products have been exported to more than 80 countries – USA, Europe, South America and Southeast Asia, etc. With the hard-work of R&D team and over 300 workers, Sigo optical company is not only in a leadership position of manufacturing but also in designing safer, healthier and more fashionable lenses. To learn more, please visit www.sigooptical.com.

Find more information at www.covestro.com.
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Forward-looking statements
This news release may contain forward-looking statements based on current assumptions and forecasts made by Covestro AG. Various known and unknown risks, uncertainties and other factors could lead to material differences between the actual future results, financial situation, development or performance of the company and the estimates given here. These factors include those discussed in Covestro’s public reports which are available at www.covestro.com. The company assumes no liability whatsoever to update these forward-looking statements or to conform them to future events or developments.