Description
Loctite 4902 Cyanoacrylate Adhesive: flexible adhesive for medical and industrial applications
Loctite 4902 is a flexible cyanoacrylate adhesive designed for demanding environments: medical, electronic, and industrial. It bonds quickly, holds strong, and resists dynamic stresses.
Its elastic formulation absorbs shocks and vibrations, where rigid adhesives would crack. Ideal for rubber, flexible plastics, and difficult substrates.
Biocompatible according to ISO 10993, it meets the strict standards of the medical sector without compromising on industrial performance.
Presentation of Loctite 4902: a high-flexibility cyanoacrylate
Loctite 4902 is a single-component cyanoacrylate adhesive developed by Henkel. It stands out from classic cyanoacrylates due to its high flexibility after polymerization, making it suitable for assemblies subjected to repeated mechanical stress.
It is suitable for both medical and industrial applications, particularly for bonding soft or deformable materials.
Composition and physical characteristics
Loctite 4902 is formulated with a modified ethyl cyanoacrylate base. This formulation gives it higher elasticity than standard cyanoacrylates while maintaining good tensile strength.
Its main physical characteristics:
- Appearance: transparent liquid, slightly viscous
- Viscosity: approximately 200 to 500 mPa·s, ideal for less porous surfaces
- Setting time: 10 to 60 seconds depending on the substrate and ambient humidity
- Tensile strength: up to 15 MPa on steel
- Elongation at break: high, this is the key criterion that distinguishes it
- Service temperature: -55 °C to +80 °C
- Biocompatibility: compliant with ISO 10993 requirements for medical applications
| Product | Type | Viscosity | Flexibility | Main Use |
|---|---|---|---|---|
| Loctite 4902 | Flexible ethyl cyanoacrylate | 200-500 mPa·s | Very high | Medical, flexible assemblies |
| Loctite 401 | Standard ethyl cyanoacrylate | ~100 mPa·s | Low | General use, rigid substrates |
| Loctite 454 | Cyanoacrylate gel | ~45,000 mPa·s | Low | Vertical, porous surfaces |
| Cyberbond CB 2250 (Cyberbond) | Flexible cyanoacrylate | ~300 mPa·s | High | Rubber, flexible plastics |
Technical performance and areas of application
Loctite 4902 is a medical-grade cyanoacrylate adhesive, formulated to provide high flexibility after polymerization. It resists repeated mechanical stress without cracking.
Its medium viscosity (~1,000 mPa·s) allows for precise application without running. The fixture time is fast: a few seconds to a few minutes depending on the substrate and ambient conditions.
It complies with ISO 10993 biocompatibility requirements, making it a suitable choice for applications in contact with skin or medical equipment.
Assembly of medical devices and mixed substrates
Loctite 4902 excels in multi-material assemblies: metal/plastic, rubber/metal, flexible/rigid plastic. Where a rigid glue would break, it absorbs movement.
Examples of concrete applications:
- Fixing sensors onto wearable medical devices
- Assembling components in TPU, treated silicone, ABS, or polycarbonate
- Bonding flexible seals in industrial equipment subjected to vibrations
- Repairing rubber or elastomer parts
| Product | Flexibility | Medical Grade | Viscosity | Main Use |
|---|---|---|---|---|
| Loctite 4902 | High | Yes (ISO 10993) | ~1,000 mPa·s | Mixed substrates, medical, industrial |
| Loctite 4861 | Very high | Yes | ~500 mPa·s | Highly flexible assemblies, medical |
| Loctite 406 | Low | No | ~5 mPa·s | Plastics and rubbers, general use |
| Permabond 105 | Low | No | ~100 mPa·s | Rigid structural bonding, metal/plastic |
Loctite 4902 vs. other cyanoacrylates: comparison table
Comparison with classic Loctite cyanoacrylates and other manufacturers
Loctite 4902 distinguishes itself from standard cyanoacrylates by its exceptional flexibility and shock resistance. It is not a versatile universal adhesive: it is an adhesive designed for assemblies subjected to vibrations, deformations, or dynamic stresses.
Compared to Loctite 406 (low viscosity rigid cyanoacrylate), 4902 offers a much more flexible bond line. Ideal when the substrate moves or flexes slightly after assembly.
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