LOCTITE SI 5248
Harmonization Code : 2901.10.00.00 | Acyclic hydrocarbons; Saturated
Main features
- UV/Shadow-Area Dual Cure
- Thixotropic Low-Migration Sealing
- Flexible Electrical Insulation
Product Description
LOCTITE SI 5248 Light-Cure Silicone Sealant is a one-part, thixotropic alkoxy silicone for gasketing and sealing assemblies that need a flexible, low-migration material. UV light develops functional strength rapidly in exposed regions, while atmospheric moisture cures areas hidden from the light. The straw-colored material skins in about 11 minutes and becomes tack-free in about 14 minutes where UV is absent. Full performance develops over 72 hours. Under the specified cure, the silicone reaches at least 135% elongation, at least Shore A 25 hardness, and volume resistivity of 8.3 x 10^13 ohm-cm.
Key features
- Dual UV and moisture cure: Light cures exposed regions while atmospheric moisture cures shadowed areas.
- Thixotropic low-migration sealing: Reduced liquid migration helps retain material after application.
- Flexible electrical insulation: The specified cure provides at least 135% elongation and 8.3 x 10^13 ohm-cm volume resistivity.
Applications
Applications include flexible gasketing and sealing of glass, ceramics, metals, and compatible plastics.
TDS, SDS & Technical Documents
Technical Specifications
General Properties
Physical Properties
Mechanical Properties
Electrical Properties
Chemical Properties
Additional Information
As-supplied properties
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Appearance | Straw-colored liquid | As supplied | |
| Specific gravity | 1.05 | As supplied | |
| Solids / non-volatile content | At least 95 | % | Typical property |
| Viscosity | 50,000 to 80,000 | mPa s (cP) | Brookfield RVT, spindle 6, 2.5 rpm, 25 deg C |
Cured properties
Mechanical values use the specified light cure plus ambient post-cure; other rows retain their listed test conditions.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Shore hardness | At least 25 | Shore A | ISO 868; 70 mW/cm^2 for 60 s per side plus 3 days at 22 deg C / 50 +/- 5% RH |
| Elongation | At least 135 | % | ISO 37; same cure as Shore hardness |
| Tensile strength | At least 1 | N/mm^2 | ISO 37; same cure as Shore hardness |
| Tear strength | At least 1.7 | N/mm | ISO 34-1, Die B; same cure as Shore hardness |
| Water absorption | 0 | % | ISO 62, 24 h in water at 22 deg C; 40 mW/cm^2 for 60 s per side plus 7 days at 22 deg C / 50% RH |
| Volume resistivity | 8.3 x 10^13 | ohm-cm | IEC 60093; cured material |
| Compression set at 22 deg C | 6 | % | ASTM D395, Method B, 70 h |
| Water vapor transmission rate | 0.455 | g/(h m^2) | ASTM E96 |
