Loctite adhesives for bonding NBR rubber (Nitrile Butadiene Rubber) to NBR are specialized instant adhesives (cyanoacrylates), designed to create strong, flexible, and oil-resistant bonds within seconds.

The most common and effective Loctite grades for this application include:

1. Loctite adhesives specifically for NBR-to-NBR bonding

• Loctite 406 (Highly recommended): This is a very low-viscosity instant adhesive, specially designed for plastics and elastomers such as NBR and EPDM. It cures extremely fast, forms a thin bond line, and performs well in oil environments and temperatures from −40°C to 120°C.
• Loctite 480: A black, rubber-toughened cyanoacrylate adhesive. It is ideal when high impact resistance, flexibility, and moisture resistance are required—especially for rubber parts subject to continuous bending.
• Loctite 401: A fast-curing, general-purpose adhesive that can be used if 406 is not available. It bonds rubber, plastics, and metals well, and is particularly effective on porous surfaces.

2. Characteristics of Loctite adhesives for NBR

• Fast curing: Bonds parts within seconds to under one minute.
• Oil and chemical resistance: NBR is known for oil resistance, and Loctite adhesives (especially 406 and 480) maintain strong bonding performance in such environments.
• Flexibility: Products like Loctite 480 help prevent brittle failure or cracking when the rubber flexes.
• Low viscosity (liquid form): Allows easy penetration into small rubber joints.

3. Bonding process for NBR using Loctite

To achieve the best bonding strength, especially with NBR, the following steps should be followed:

• Surface preparation: Remove oil, grease, and dirt from both rubber surfaces using a cleaner such as Loctite 7070.
• Use primer (if needed): Although NBR is not highly inert, for optimal performance, Loctite SF 770 can be applied before bonding.
• Apply adhesive: Apply a small amount of Loctite 406 or Loctite 480 to one surface.
• Assembly: Press the two surfaces together firmly for 10–30 seconds.

Note: For maximum strength, allow the adhesive to fully cure for 24 hours.