Solvent and Chemically Resistant Fluro Liquid Silicone Rubber - Silastic® FL 70-9201 (F-LSR)

Silastic® FL 70-9201 F-LSR is offered as a two-component, pigmentable soft paste containing fluorosilicone. It is specially formulated for liquid injection molding. On heating, it is cured to a 70 durometer material. The cured rubber material exhibits superior resistance to diverse chemicals and solvents over a temperature range of -63°C to +175°C under immersion conditions, and up to +225°C under dry heat conditions.

Applications of of Silastic® FL 70-9201 F-LSR

The following are the applications of Silastic® FL 70-9201 F-LSR:

  • Thin, high-precision coatings
  • Complex components with close tolerances
  • Solvent and chemically resistant molded components
  • Membranes, gaskets and O-rings for challenging static and dynamic sealing purposes
  • Extrusion onto fabrics, belts, wires, and other surfaces

Typical Properties of Silastic® FL 70-9201 F-LSR

The following table presents the typical properties of Silastic® FL 70-9201 F- LSR:

Test1

Property

Unit

Result

Color Part A Light yellow
Color Part B White
CTM 1094 Viscosity Part A (shear rate 10 s-1) Pa.s 1000
CTM 1094 Viscosity Part B (shear rate 10 s-1) Pa.s 1000
As molded2
ASTM D792 Specific Gravity 1.42
ASTM D2240 Hardness Shore A 68
DIN 53504, S2 Tensile strength MPa 5.8
DIN 53504, S2 Elongation at break % 180
ASTM D624B Tear Strength kN/m 15
ASTM D3S5 Compression Set % 233/314
Post-cured2
ASTM D2240 Hardness Shore A 70
DIN 53504, S2 Tensile strength MPa 6.1
DIN 53504, S2 Elongation at break % 180
ASTM D624B Tear Strength kN/m 15
ASTM D3S5 Compression Set % 133/134
ASTM D 471 Fluid resistance - volume swell5
IRM 903, 168 hrs 150°C % 2.9
Biodiesel, 168 hours 40°C % 3.1
Reference Fuel C, 168 hours 23°C % 20.7
FAM B, 168 hours 23°C % 23.3

1CTM: Corporate Test Method, copies of CTM’s are available on request.
ASTM: American Society for Testing and Materials.
DIN: Deutsche Industrie Norm.
2Cure conditions, As molded 10 minutes at 120°C, Post-cured 4 hours at 200°C.
3Tested according to method B, type II (6mm), molded buttons, 22hrs 175°C.
4Tested according to method B, type II (6mm), plied disks, 22hrs 177°C.
5Injection molded slab, Post-cured 4 hours at 200°C.

Key Features and Advantages of Silastic® FL 70-9201 F-LSR

The following are the key features of Silastic® FL 70-9201 F-LSR:

  • Two-component product with convenient 1:1 mix ratio
  • Has a wide cure temperature range of 130-200°C
  • High temperature resistance
  • Rapid cure platinum technology, no cure by-products
  • Superior resistance to automotive fuels and oils
  • Maintains elasticity at low temperatures: TR10 -66°C, Tg -68°C

The key benefits of Silastic® FL 70-9201 F-LSR are as follows:

  • Facilitates short process cycle times
  • Delivers reliable sealing
  • Fabricates flash-free components
  • Ideal for highly automated injection molding processes
  • Enables intricate part fabrication with close tolerances

Mixing

Silastic® FL 70-9201 F-LSR is supplied as two components Part A and Part B. These parts must be mixed in a 1:1 ratio. For production, meter mix equipment is strongly recommended for pumping, metering and mixing the two parts without entrapping air.

Pot Life

At room temperature, the usable life of Silastic® FL 70-9201 F-LSR is 48h from the time of mixing of the two components. The usable life of Silastic® FL 70- 9201 F-LSR is 18 months from the manufacturing date when kept in the original unopened containers at or below 32°C. This product is available in lot matched pail kits (2x 22kg).

Cure Rate of Silastic® FL 70-9201 F-LSR

Silastic® FL 70-9201 F-LSR is cured within seconds when heated to 150°C. The cure time for a specific component is the time required to bring the part to this temperature. The cure time for Silastic® FL 70-9201 F-LSR is a function of cure temperature and the dimensions of the component to be cured. It is possible to optimize the cure time for the specific dimensions of components to be molded.

Cure Inhibition and Clean-Up/Removal

The avoidance of contamination is indispensable because the presence of substances such as tin complexes, sulfur, amines and some peroxides can inhibit the cure mechanism of Silastic® FL 70-9201 F-LSR. The uncured product can be cleaned up using solvents like Dow Corning® OS Fluids, toluene, naphtha, xyline, and mineral spirits. IPA can also serve this purpose.

This information has been sourced, reviewed and adapted from materials provided by Dow Corning Automotive.

For more information on this source, please visit Dow Corning Automotive.

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