SLM ELASTOSIL TC 850 A/B

RTV-2 Thermally Conductive Encapsulant
SLM ELASTOSIL TC 850 A/B is a pourable, 1:1 two-component silicone rubber encapsulant that vulcanizes at
room temperature and accelerates on heat.

Properties
• Two-part system, 1:1 mixing ratio.
• Easy to mix and pour.
• Room temperature curing but accelerates on application of heat.
• Excellent durability

Specific features
• Moderate Shore A hardness
• Good thermal conductivity (approx. 0.85 W/mK)
• No post curing required.
• Excellent reliability over a wide range of temperature
• Aids heat dissipation

Technical data

Application details

SLM ELASTOSIL TC 850 A/B thermally conductive encapsulant is suitable as a potting material for:
• Encapsulants for PCB assembly
• Power modules
• Adaptors
• Inverters
• Transformers
• Ballasts
• Sensors
• Electronic control units

Processing
Important
Only A & B components with the same batch number may be processed together!

• Application methods
Manual or automated needle dispenser.

• Mixing and deairing
The product is supplied for 1:1 mix ratio. Prior to use carefully mix the individual components as both of part A & B can
have filler settlement in the bottom. Mixing of individual components has to be carried out till all the settled fillers mixed up
uniformly.
Component A of SLM ELASTOSIL TC 850 A/B contains platinum catalyst. Component B the crosslinker hydrogen. Even
traces of platinum catalyst may cause gelling of the component containing the crosslinker. Therefore tools (spatula, stirrers
etc) used for handling the platinum containing component or the catalyzed compound must not come into contact with this
component.

• Curing
SLM ELASTOSIL TC 850 A/B, the silicone encapsulants may be either room temperature or heat cured. Room
temperature cure encapsulants may also be heat accelerated for faster cure.
The reactivity can be adjusted within wide limits by adding catalyst OL or inhibitor ViP5 to suit the processing requirements
of the particular applications. Catalyst OL increases the reactivity i.e. pot life and curing time are reduced. Inhibitor ViP5 is
a pot life extender and prolongs pot life and curing time. 

• Cleaning
If removal of uncured silicone rubber from machines or dispensing equipment is necessary, white spirit or similar non-polar
solvents are recommended. However, cleaning ideally should take place before the rubber is fully vulcanized. Cured
silicone rubber can be removed by mechanical means, preferably in combination with a swelling agent (solvent).

• Notes
Examples of inhibiting contaminants are sulfur containing materials, plasticizers, urethanes, amine containing materials
and organometallic compounds – especially organotin compounds. If a substrate’s ability to inhibit cure is unknown, a
small-scale test should be run to determine compatibility.

• Storage
SLM ELASTOSIL TC 850 A/B has a shelf life of at least 8 months when stored between 5°C and 30°C in the originally
sealed container. But shelf life can be extended based on the storage condition of the material. The ‘Best use before end’
date of each batch appears on the product label.

Detailed processing instructions are given in our brochure “ROOM TEMPERATURE VULCANIZING
(RTV) SILICONES – MATERIAL AND PROCESSING GUIDELINES