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OPT 7020

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Optically Clear
Silicone Rubber Encapsulant
Transparent Potting Compound

  • Optically clear
  • Compliant
  • Room or low temperature cure
  • Non-yellowing catalyst system
  • Low shrinkage
  • Excellent for protecting LEDs or solar applications

Opti-tec 7020 is a 2 part, clear liquid silicone elastomer which will cure at room temperature or can be accelerated at elevated temperatures. It has a low viscosity, which allows for ease of flow around complex parts, providing electrical insulation and shock resistance. Its combination of transparency, non-yellowing and compliance makes it suitable for encapsulation of sensitive electronic or opto-electronic parts (e.g. LEDs), protecting the components from vibration, moisture and atmospheric contaminants.


  • Optical assembly
  • Opto-electronics, photonics, LEDs
  • Optical encapsulation & glob topping, casting, potting
  • Solar panels
  • Electronics potting

Clear potting for electronics
Opti-tec 7020 provides clear, non-yellowing encapsulation for electronics and opto-electronics


  • Opti-tec 7020 has a convenient 10:1 mixing ratio for use in automatic dispensing equipment or hand mixing
  • Opti-tec 7020 has a low viscosity which allows for ease of flow around complex parts, providing electrical insulation and shock resistance
  • Opti-tec 7020 contains no solvents
  • Opti-tec 7020 has a non-yellowing catalyst system
  • Opti-tec 7020 has a chemical composition which provides hydrolytic stability and reversion resistance. It is an addition cure silicone with a platinum catalyst.
Typical Properties
Uncured properties
Colour Part A - clear
Part B - clear
Mixed - clear, colourless
Viscosity (mPa.s) Part A - 4000
Part B - 500
Mixed - easily pourable
Specific gravity Part A - 1.02
Part B - 1.01
Mix ratio 10:1 Part A to Part B
Pot life (@ 23°C) 4 hours
Cure schedule (approx maximum time) 25°C - 20 hours
100°C - 60 mins
Cured properties
(1 hour @ 100°C)
Hardness, Shore A 40
Temperature range -60 to 200°C
Tensile strength 4.8 MP
Elongation at break 100%
Linear shrinkage < 0.1%
CTE (ppm/°C) 275
Dielectric strength (kV/mm) 20
Dielectric constant @ 1000Hz 2.69
Dissipation factor @ 1000Hz 0.0006
Volume resistivity (ohm-cm ) 1.7 x 1015
Thermal conductivity (W/m K) 0.18
Specific heat (kJ/kg) 1.255
Refractive index @ 589nm 1.405
Transmittance @ 400nm 90.3%

Opti-tec 7020 Silicone Potting Compound Transmission Curve
Transmittance of Opti-tec 7020 @ 1cm path length

Opti-tec 7020 is supplied in matched kits in a 10 to 1 ratio of Part A to Part B - standard size is 1.1kg total. Unopened containers have a shelf life of 12 months at ambient temperatures. Alternatively, Opti-tec 7020 is supplied in pre-weighed 250 gram twinpacks.

Opti-tec 7020 1.1kg kit Opti-tec 7020 Twinpack
Opti-tec 7020 1.1kg kit Opti-tec 7020 250g twinpack


Weigh 10 parts of Part A to 1 part of Part B. Allowable tolerance on the measured weight for either Part A or Part B is +/-2.5%. The mixing container should be 4 to 5 times larger than the volume of silicone. Use stainless steel, HDPE, polypropylene, etc. Using clean tools, thoroughly mix the A and B components.

The twinpack is a clear film sachet, with Part A and Part B separated by a removable clip and rail divider. To mix the adhesive, remove the divider and massage the two parts together within the twinpack. The two parts are mixed until they appear uniform, which usually takes about 2 to 3 minutes. Cut off one corner of the twinpack, and dispense to required area, or to syringe for more precise application.

Care should be taken to avoid excessive aeration. For many applications, natural degassing will be sufficient. If degassing is required, intermittently evacuate at 20-40 mbar for 15-30 minutes. Leave for a few minutes after releasing the vacuum to allow surface bubbles to collapse.

Cure begins as soon as the components are mixed in the recommended ratio. Complete cure is normally achieved in 16 to 24 hours at ambient temperatures of 20-30°C. Cure can be accelerated by heating to 50-120°C.

Part number Description
OPT7020-1.1KG 1.1kg kit
OPT7020-250G 250g twinpack

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August 2015
Version 4.2

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17 Station Field Industrial Estate, Banbury Road
t +44 1865 842842  e info@intertronics.co.uk
Statements, technical information and recommendations contained herein are based on tests we believe to be reliable but they are not to be construed in any manner as warrantees expressed or implied. The user shall determine the suitability of the product for his intended use and the user assumes all risk and liability whatsoever in connection therewith.
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