LOCTITE EA 3943
Harmonization Code : 3214.10.00 | Putty and other mastics | Resin cements, caulking compounds and other mastics

Main features
- Cannula-Focused Medium-Viscosity Dispensing
- Sub-5-Second UV Fixture
- UV-Fluorescent Assembly Inspection
Product Description
LOCTITE AA 3943 is a one-part, medium-viscosity UV and visible-light acrylic adhesive for bonding stainless-steel cannulae into hubs, syringes and lancets. Its 6,000 to 7,500 mPa s viscosity at 25 deg C is suited to dispensing on cannulae before hub assembly, including larger-gap needle configurations. The adhesive fixtures in less than 5 seconds under the stated 365 nm UV conditions and fluoresces under black light for assembly inspection. The cured material combines 271% elongation at break with Shore D 69 hardness, supporting flexible medical-device bonds across the specified glass, plastic and metal substrates.
Key features
- Needle-assembly viscosity: 6,000 to 7,500 mPa s at 25 deg C supports controlled cannula-to-hub dispensing.
- Fast light cure: Fixture time is less than 5 seconds at 30 mW/cm^2 and 365 nm on glass.
- Inspection fluorescence: UV fluorescence supports visual confirmation of adhesive presence in bonded assemblies.
Applications
Applications include stainless-steel cannula bonding in hubs, syringes and lancets, plus documented glass, plastic and metal component bonding for disposable medical-device assembly.
TDS, SDS & Technical Documents
Technical Specifications
General Properties
Physical Properties
Thermal Properties
Chemical Properties
Mechanical Properties
Additional Information
As-supplied properties
Typical uncured-product values at 25 deg C unless otherwise stated.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Appearance | Transparent to hazy liquid | Free of undissolved solids | |
| UV fluorescence | Positive | Inspection under UV light | |
| Specific gravity | 1.04 | At 25 deg C | |
| Gardner color | 3 or less | Typical limit | |
| Viscosity | 6,000 to 7,500 | mPa s | Brookfield RVT, spindle 4, 20 rpm, 25 deg C |
Final-state properties
Typical cured-material values after 100 mW/cm^2 at 365 nm for 30 seconds per side using an electrodeless D bulb, unless otherwise stated.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Glass transition temperature | 55 | deg C | ASTM E 228 |
| Shore hardness | 69 | Durometer D | ISO 868 |
| Elongation at break | 271 | % | ISO 527-3 |
| Tensile strength | 24 | N/mm^2 | ISO 527-3 |
| Tensile modulus | 441 | N/mm^2 | ISO 527-3 |
| UV depth of cure | At least 1.5 | mm | 100 mW/cm^2 at 365 nm for 10 seconds, electrodeless D bulb |
| Block shear strength | 9.7 | N/mm^2 | ISO 13445, polycarbonate to polycarbonate, 100 mW/cm^2 at 365 nm for 30 seconds |





















