RTV 120 - High Initial Tear Strength Moulding Silicone
2 component, room temperature condensation curing silicone compound.
Mix ratio = 20:1 (100 grams Part A : 5 grams Part B).
Available as: 21.0Kg, 5.25Kg, or 1.05Kg.
Fast or Slow cure available.
 
Can be mixed in any ratio desired with RTV128 to adjust Shore A hardness.
 
RTV 120 is used as mould making material (production of
negatives).  The cured product is an exceptionally flexible
rubber with very high mechanical properties and good shelf-life stability. 
It's suitable for mould making of intricate
patterns with extremely good pick up of fine details. 
Softer grades are better suited for where there are deep
undercuts. There is no release agent required for de-moulding.
For the production of multipart moulds and to avoid 
adhesion of RTV 120 to itself, use release agents. Ideal for mould making and modelling, vacuum casting.
 
Key Features
High resistance to initial tearing and tear propagation
Very good flow properties
Can be made thixotropic
Available with either Fast or Slow catalyst.
 
Applications
Mould making
Suitable for polyester, epoxides, wax
 
 
Thixotropic Adjustment
By addition of the component Thixo Additive, the silicone
rubber can be made thixotropic for special applications,
i. e. the compound is then no longer liquid and castable,
but brushable to pasty. For this, add approx. 0.5 to 1.5% of
Thixo additive to the already mixed compound of RTV 120
including Regular Catalyst. The thixotropic effect already
occurs after a short period of time.
 
RTV120: 95-100 parts by weight
Catalyst: 5 parts by weight (Fast or Slow)
BS4 Thixo: 0.5-1.5 parts by weight

Viscosity @20°C (mPa·s):
RTV120 35,000, Fast 30, Slow 100, Thixo 300
Mixed viscosity(mPa·s): Fast 24,000, Slow 32,000
Pot life (1000g): Regular 100 minutes,  Slow 20 minutes
 
Cured Elastomer
Colour: white
Tack-free: Fast 20 hours, Slow 10 hours
Hardness (24h) Shore A DIN 53505: Fast13, Slow 17
Hardness (7d) Shore A DIN 53505:
Fast 21, Slow 19, Thixo 20
Service temperature (°C):  Fast 180,  Slow 180
Tensile strength (N/mm2) DIN 53504:  Fast 3.0,  Slow 2.5
Elongation at break (%) DIN 53504:  Fast 450,  Slow 450
Resistance to tear propagation (N/mm) ASTM D 624 B:
Fast 20,  Slow 20
Linear dimensional change (%):  Fast 1,  Slow 1