What is SOPRIFIX SO21B? A blue thread locker
SO21B is a pre-applied adhesive product for locking and sealing applications on threads. The SO21B product is applied in our factory, and remains inert until final assembly. Once assembled in the mating part, the pre- applied film cures to lock and seal the assembly.

Application of SO21B to fasteners
Fasteners coated with SO21B product prevent loosening through vibration to provide locking and sealing of threaded assemblies for applications such as: screws, nuts, threaded fasteners…
Features of Soprifix SO21B
Type | Color |
---|---|
Epoxy microencapsulated Resin | Blue |
Properties of assembled fasteners
Screw-in torque (Cfv) | Breakaway torque (Cdec) | Prevailing off-torque (Cfd) | Temperature range | Cure time at 23°C | Coefficient of friction |
---|---|---|---|---|---|
0.55 N.m | 30 N.m | 22 N.m | -54°C / +150°C | 72 hours (100%) |
0,14 Zinc organic 0,19 Zinc plate |
Note : Tests are conducted on M10x1,5 class 10.9 zinc organic finish bolts and M10x1,5 zinc nuts. Performance may vary
depending on fastener size and finish.
Resistance to fluids
Temperature | % Initial Strength | |
---|---|---|
SW30 Synthetic oil | 150°C | 88 |
Brake fluid | 150°C | 94 |
50/50 coolant | 100°C | 109 |
Transmission fluid | 150°C | 104 |
Gasoline | 23°C | 100 |
Gasoline / Ethanol | 23°C | 108 |
15W40 Lubricant | 150°C | 110 |
Cyclic aging | -40 to +50°C | 261 |
Heat age | 150°C | 84 |
Note : The tests were conducted on M10x1,5 zinc organic finish bolts and a zinc plate nuts. Assembled fasteners were
aged at the temperature listed above for 168 hours and allowed to cool to room temperature before breakaway test.
Service life and storage
Coated fasteners with SO21B product are recommended to be stored for 2 years before final assembly in a cool and dry location with temperatures between -10°C to +35°C. Optimal storage is 25 +/-4° C with 50% or below relative humidity.
General Information
The data contained on this data sheet is representative of the performance of fasteners coate with SO21B product. However, we recommend to conduct preliminary tests to determine suitability for your application.