Loctite 401 Surface Insensitive Instant Adhesive (Cyanoacrylate)
Typical Properties
| Specific Gravity @ 25 °C | 1.1 |
| Flash Point | See SDS |
| Viscosity, Cone & Plate, mPa·s (cP): Temperature: 25 °C, Shear Rate: 3,000 s-1 | 70 to 110LMS |
| Viscosity, Brookfield – LVF,25°C,mPa·s (cP): Spindle 1, speed 30 rpm | 100 to 120 |
Loctite 401 is a low-viscosity, fast-curing cyanoacrylate instant adhesive designed for bonding difficult or porous materials. It delivers uniform stress distribution and high shear strength, making it ideal for industrial assembly applications involving metals, plastics, elastomers, wood, paper, leather, and fabric.
Directions for Use
Loctite 401 is widely used in electronics assembly, automotive manufacturing, medical device production, and general industrial bonding. Its surface-insensitive formula means it bonds effectively even on slightly oily or acidic surfaces, reducing the need for surface preparation and speeding up production lines.
1. Bond areas should be clean and free from grease. Clean all surfaces with a Loctite® cleaning solvent and allow to dry.
2. To improve bonding on low energy plastic surfaces,Loctite® Primer may be applied to the bond area. Avoid applying excess Primer. Allow the Primer to dry.
3. LOCTITE® Activator may be used if necessary. Apply it to one bond surface (do not apply activator to the primed surface where Primer is also used). Allow the Activator to dry.
4. Apply adhesive to one of the bond surfaces (do not apply the adhesive to the activated surface). Do not use items like tissue or a brush to spread the adhesive. Assemble the parts within a few seconds. The parts should be accurately located, as the short fixture time leaves little opportunity for adjustment.
5. LOCTITE® Activator can be used to cure fillets of product outside the bond area. Spray or drop the activator on the excess product.
6. Bonds should be held fixed or clamped until adhesive has fixtured.
7. Product should be allowed to develop full strength before subjecting to any service loads (typically 24 to 72 hours after assembly, depending on bond gap, materials and ambient conditions).
Storage and Shelf Life Store
Loctite 401 in a cool, dry place between 2°C and 8°C (35°F to 46°F). Keep container tightly sealed when not in use. Avoid exposure to moisture, heat, and direct sunlight. Shelf life is 12 months from date of manufacture when stored under recommended conditions. Do not freeze. Keep out of reach of children. For best results, use within 4–6 weeks after opening. If the nozzle becomes clogged, replace the tip — do not attempt to unclog with sharp objects as this may damage the bottle and cause spills.Always keep the cap on tightly after each use.
FAQ
Q: How long does Loctite 401 take to cure?
A: Fixture time is 5–90 seconds depending on substrate and humidity. Full cure takes up to 24 hours.
Q: What materials can Loctite 401 bond?
A: Metals, plastics, rubber, elastomers, wood, paper, leather, and fabric. Especially suited for porous and difficult-to-bond surfaces.
Q: Does Loctite 401 require an activator?
A: No activator is required for most substrates. For inert plastics like polyethylene or polypropylene, Loctite 7452 activator is recommended.
Q: What is the temperature resistance of Loctite 401?
A: Loctite 401 maintains bond strength from -55°C to +80°C (-67°F to +176°F).
Q: What is the difference between Loctite 401 and Loctite 406?
A: Loctite 406 is specifically formulated for rubber and plastics with higher bonding speed on those surfaces. Loctite 401 is a general-purpose formula suited for a wider range of materials.
