LOCTITE 5240
Harmonization Code : 3208.20.90 | Paints and varnishes that are dispersed or dissolved in a non aqueous medium
Main features
- Light-and-Moisture Dual Cure
- Shear-Thinning Cavity Filling
- Flexible Electrically Insulating Rubber
Product Description
LOCTITE SI 5240 is a clear, flowable one-component alkoxy silicone for bonding, potting, coating, and sealing. UV or visible light rapidly cures exposed material, while atmospheric moisture provides secondary cure in shadowed regions. The shear-thinning liquid supports controlled dispensing and uniform cavity filling before forming a flexible silicone rubber. Typical cured properties include Shore A hardness of at least 40, tensile strength of at least 3 N/mm^2, and elongation from 250% to 450% at the specified cure condition. Full ambient property development occurs over approximately 72 hours.
Key features
- Light-and-moisture dual cure: Exposed material cures with UV or visible light, while atmospheric moisture supports shadowed regions.
- Shear-thinning cavity flow: The 15,000 to 35,000 mPa s liquid supports controlled dispensing and uniform filling.
- Flexible insulating silicone: The cured rubber combines high elongation with measured dielectric and mechanical properties.
Applications / Suitable for
- Bonding and sealing components
- Potting and cavity filling
- Protective coating of assemblies
TDS, SDS & Technical Documents
Technical Specifications
General Properties
Physical Properties
Mechanical Properties
Electrical Properties
Curing Conditions
Additional Information
As-supplied / before-processing properties
Typical values and characteristics for the product before cure, application, or assembly.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Appearance | Clear with yellow-green tint | - | As supplied |
| Chemical type | Alkoxy silicone | - | One-component material |
| Specific gravity | 1.06 | - | 23 deg C |
| Viscosity | 15,000 to 35,000 | mPa s | Brookfield RVT, spindle 5, 10 rpm, 25 deg C |
| Flow behavior | Shear thinning | - | Thixotropic as supplied |
| Primary cure mechanism | UV / visible light | - | Exposed material |
| Secondary cure mechanism | Atmospheric moisture | - | Shadowed regions |
After-processing / final-state properties
Typical values for the cured, bonded, treated, or in-service product under the listed conditions.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Shore hardness | >=40 | Shore A | 70 mW/cm^2 at 365 nm for 60 s per side, then 7 d at 22 deg C |
| Elongation at break | 250 to 450 | % | 70 mW/cm^2 at 365 nm for 60 s per side, then 7 d at 22 deg C |
| Tensile strength | >=3 | N/mm^2 | 70 mW/cm^2 at 365 nm for 60 s per side, then 7 d at 22 deg C |
| Tensile modulus at 100% strain | 1 | N/mm^2 | 70 mW/cm^2 at 365 nm for 60 s per side, then 7 d at 22 deg C |
| Tear strength | 12.6 | N/mm | 70 mW/cm^2 at 365 nm for 60 s per side, then 7 d at 22 deg C |
| Volume shrinkage | 0.8 | % | Cured material |
| Dielectric breakdown strength | 21 | kV/mm | Cured material |
| Volume resistivity | 1.2 x 10^15 | ohm cm | Cured material |
