LOCTITE AA 3921
Harmonization Code : 3506.10.00.00 | Prepared glues and other prepared adhesives, not elsewhere specified or included; products suitable for use as glues or adhesives, put up for retail sale as glues or adhesives, not exceeding a net weight of 1 kg
Main features
- 5-Second UV/Visible-Light Cure
- Transparent Cured Bondline
- High-Hardness Acrylic Adhesive
Product Description
LOCTITE® AA 3921™ is a one-component UV/visible light-curing acrylic adhesive engineered for high-speed bonding applications requiring flexibility, strong adhesion and sterilization resistance. The adhesive cures within seconds when exposed to appropriate UV or visible light sources and develops excellent adhesion to glass, plastics and metals. Its fluorescent response under UV light enables inspection of adhesive presence, making it particularly suitable for medical device assembly. LOCTITE AA 3921 was specifically developed for bonding stainless steel cannulas into hubs, syringes and lancets used in disposable needle assemblies and has been evaluated to ISO 10993-based biocompatibility protocols.
Key Features & Benefits
- UV and visible light curing acrylic adhesive.
- Rapid fixture times of approximately 5 seconds under UV/LED light.
- Fluoresces under UV light for inspection and quality control.
- Excellent adhesion to glass, plastics and metals.
- Flexible cured bond line with high toughness.
- Resistant to autoclave, ETO and gamma sterilization processes.
- Designed for disposable medical device assembly.
Recommended Applications
- Needle-to-hub bonding for syringes and cannula assemblies.
- Disposable medical device manufacturing.
- Glass-to-metal and glass-to-plastic bonding.
- UV-curable industrial assembly operations.
- Applications requiring adhesive inspection under UV light.
TDS, SDS & Technical Documents
Technical Specifications
General Properties
Physical Properties
Additional Information
As-Supplied / Before-Processing Properties
| Property | Value | Unit | Condition |
|---|---|---|---|
| Technology | UV Acrylic | — | UV / Visible Light Cure |
| Appearance | Transparent to Hazy Liquid | — | Uncured, free of undissolved solids |
| Fluorescence | Positive Under UV Light | — | Inspection aid |
| Components | One Part | — | No mixing required |
| Specific Gravity | 1.03 | — | 25°C |
| Density | 1.03 | g/cm³ | 20°C |
| Brookfield Viscosity | 100 - 200 | mPa·s (cP) | RVT, Spindle 2, 20 rpm, 25°C |
| UV Fixture Time | 5 | seconds | 100 mW/cm² LED at 365 or 405 nm |
After-Processing / Final-State Properties
| Property | Value | Unit | Condition / Method |
|---|---|---|---|
| Glass Transition Temperature (Tg) | 89 | °C | ASTM E228 |
| Shore Hardness | 67 | Shore D | ISO 868 |
| Tensile Strength | 19.5 | N/mm² | ISO 527-3 |
| Elongation at Break | 32 | % | ISO 527-3 |
| Coefficient of Thermal Expansion | 108 × 10⁻⁶ | K⁻¹ | Below Tg, ISO 11359-2 |
| Water Absorption | 2.0 | % | ISO 62, boiling water |
| Block Shear Strength (Steel to Glass) | 16.5 | N/mm² | ISO 13445 |
| Block Shear Strength (Aluminum to Glass) | 14.8 | N/mm² | ISO 13445 |
| Block Shear Strength (Polycarbonate to Polycarbonate) | 21.1 | N/mm² | ISO 13445 |
| VOC Content | <3.0 | % | 2010/75/EC |
| Environmental Classification | Aquatic Acute 1 / Chronic 1 | — | H400 / H410 |
