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Covestro lens-grade polycarbonate provides the right specs for eyewear manufacturer

Lens-grade polycarbonate
For its corrective and sunglass lenses, Jiangsu Sigo Optical selected Makrolon® polycarbonate from Covestro due to improved optical purity and production yield.

Pittsburgh, April 4, 2018 — 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.

About Covestro LLC:

Covestro LLC is one of the leading producers of high-performance polymers in North America and is part of the global Covestro business, which is among the world’s largest polymer companies with 2017 sales of EUR 14.1 billion. 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, electrical and electronics and medical industries. Other sectors include sports and leisure, cosmetics and the chemical industry itself. Covestro has 30 production sites worldwide and employed approximately 16,200 people at the end of 2017.

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About Sigo:

Jiangsu Sigo Optical Co., Ltd. was founded in 1998. Its factory located 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--U.S.A, 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

Makrolon® is a registered trademark of the Covestro group.

Covestro Contact:

John Skabardonis, Phone: +1 412 413 5444

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This press 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 on the Covestro website at Covestro assumes no liability whatsoever to update these forward-looking statements or to conform them to future events or developments.

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