SSL | Materials | Optics + Opt. Materials | Resins | PMMA | Outdoor Applications | Oct 16, 2020

PLEXIGLAS® Optical HT Offers Enhanced Heat Deflection Temperature and Excellent Optical Properties

With the new PLEXIGLAS® Optical HT, the Molding Compounds Business Unit of Röhm introduces a heat-resistant special molding compound providing the best possible optical quality, even at increased continuous service temperatures. With its balanced properties, it is the latest molding compound of Röhm's portfolio of branded polymethyl methacrylate (PMMA). PLEXIGLAS® Optical HT provides optical efficiency at the high standard of PLEXIGLAS® 8N, in combination with an increased heat deflection temperature similar to the PLEXIGLAS® Heatresist product family. In addition, the new special molding compound offers excellent weather resistance and durability which PLEXIGLAS® is known for. This new product provides innovative designers with advanced creative possibilities for automotive headlamps or luminaire components, which create a distinctive and vibrant appearance.

Main Features:
•    PLEXIGLAS® Optical HT is a new, crystal clear special molding
     compound for increased continuous service temperature, which provides
     product designers with greater creative flexibility
•    PLEXIGLAS® Optical HT combines excellent optical properties with
     enhanced heat deflection temperature, which makes it a durable material
     for the automotive and lighting industry

Main Technical Properties:
•    High level Vicat Softening temperature (118°C)
•    UL RTI – Resistance to Thermal Aging (105°C)
•    High Clarity – Suitable for Light guides > 500 mm
•    Weathering stability – UL f1 rating, AMECA
•    Good Processability – MVR comparable to standard material

Light transmittance, temperature and UV resistance

The materials used in optical components for automotive headlamps, high-power floodlights or road lighting, are usually subject to high standards. However, new trends in product design increase the thermal requirements on the materials to be used even further. For example, the use of high-performance LEDs with simultaneously smaller component depths.

Too often, increased heat deflection temperature is synonomous with loss of optical quality, even if such a loss is minimal. Not with PLEXIGLAS® Optical HT; it combines increased heat deflection temperature with excellent optical properties in one product.

Good processability and continuous service life

PLEXIGLAS® Optical HT is suitable for processing with all standard thermoplastic methods. The excellent flow properties are comparable to those of known basic molding compounds and allow the production of complex optical components.

"PLEXIGLAS® Optical HT was designed specifically for applications where high-performance LEDs are used," emphasizes Dr. Rüdiger Carloff, Project Manager at Innovation Management Methacrylates at Röhm, who has managed the product development. "It can resist temperatures up to 105°C. This is confirmed by the RTI rating according to the UL 746B standard. It is also perfectly suitable for lighting guides with extended light paths."

"We see plenty of potential uses for PLEXIGLAS® Optical HT in the automotive industry in particular," says Dr. Sivakumara Krishnamoorthy, Senior Product Manager Automotive in the Molding Compounds Business Unit at Röhm. "We believe that PLEXIGLAS® Optical HT provides an excellent material solution for long light guides and other demanding optical components of headlamps, which are all subject to high thermal stress."

Dr. René Kogler, Head of Product Management for Lighting, Extrusion, Optics at Röhm adds, "We responded to the market's demand for higher heat deflection temperature of optics to provide greater design flexibility for luminaires with PLEXIGLAS® Optical HT. 15°C increase in continuous service temperature compared to the current standard. This opens new doors in luminaire design without loss of clarity and transmittance. Customers can continue to rely on the established PLEXIGLAS® properties such as high UV and weather resistance as well as recyclability."

Additional information on Röhm's new PLEXIGLAS® Optical HT can be found at

About Röhm:

With 3,500 employees and 15 production sites worldwide, Röhm is one of the world's leading manufacturers in the methacrylate business. The medium-sized company with branches in Germany, China, the USA, Russia, and South Africa has more than 80 years of experience in methacrylate chemistry and a strong technology platform. Our best-known brands include PLEXIGLAS®, ACRYLITE®, DEGALAN® and DEGAROUTE®.
Röhm is a worldwide manufacturer of PMMA products sold under the PLEXIGLAS® and PLEXIMID® trademarks on the European, Asian, African and Australian continents and under the ACRYLITE® and ACRYMID® trademarks in the Americas. -