Optical Silicone Vs. PC & PMMA

Optically Clear Silicone is rapidly replacing traditional optical grade materials such as Polycarbonate, PMMA, and Glass.  An evolving list of design demands that only silicone can solve is driving this revolution. 

Silicone’s unique combination of material properties set it apart from the alternatives. Some of the key highlights include: 

1.     Wide Operating Temperature Range (-40F to 400F) 

2.     Superior UV Aging & Weathering Resistance  

3.     Strong Impact Resistance (against vibration and vandalism)  

4.     Extremely Light Weight 

5.     High UL 94 Flammability Resistance Ratings 

Optical Silicone After Heat Aging, Compared to Polycarbonate and PMMA
Image courtesy of Dow

Beyond durability, the unique properties of injection molded liquid silicone rubber offers design freedoms that other materials cannot. Unlike thermoplastics that contract when injected into a mold, silicone expands in the mold – helping solve several issues such as:  

1.     Sink Marks from Thick Cross-Sections  

2.     Micro-Feature Replication (such as textures) 

3.     Under-Filled Sharp Features 

Silicone’s flexibility and forgiveness is an added bonus that other materials do not have, making it possible for designers to incorporate unique design features such as: 

1.     Small Angles & Undercuts (without sticking in the mold) 

2.    Long, Thin Features (without breaking when ejected) 

Optically Clear Silicone is also finding a home in medical applications thanks to its purity, with several grades meeting USP Class VI standards for biocompatibility.  These clear silicones have very low levels of both leachables and extractables, making it ideal for use in medical, diagnostic, and dental applications.

If you believe that silicone optics can help solve one of your design challenges, visit our website at www.sur-seal.com to get in-touch with an application engineer.