Loctite 415

LOCTITE 415 is a one-component, high viscosity cyanoacrylate adhesive formulated with methyl cyanoacrylate chemistry for general purpose industrial bonding applications. The uncured material appears as a clear, colorless to slightly hazy or light yellow liquid and does not require mixing before use. Curing is initiated by atmospheric humidity and occurs rapidly when the adhesive is confined between close fitting surfaces. Although functional strength is achieved quickly, the bond continues to develop and reaches full chemical and solvent resistance within 24 hours at 22°C.

The product is particularly suitable for bonding metal substrates and is also effective on rubbers and many plastics including ABS, PVC, polycarbonate, phenolic materials, neoprene and nitrile rubber. It has been tested to Military Specification Mil-A-46050C and qualified under Commercial Item Description A-A-3097 in certain regions. The uncured material has a specific gravity of approximately 1.1 at 25°C. Viscosity measured by cone and plate method at 25°C ranges from 900 to 1,500 mPa·s, while Brookfield viscosity at 25°C typically falls between 1,100 and 1,600 mPa·s. Vapour pressure is less than 1 hPa.

Fixture times depend on the substrate at 22°C and 50% relative humidity, with steel typically achieving handling strength in 30 to 60 seconds, aluminum in 40 to 80 seconds, zinc dichromate in 30 to 90 seconds, ABS in 20 to 50 seconds, PVC and polycarbonate in 30 to 90 seconds, phenolic in 10 to 40 seconds, and elastomers such as neoprene and nitrile rubber in less than 10 seconds. Cure speed is influenced by bond gap thickness and ambient humidity, with thinner bond lines and higher humidity accelerating the cure rate. Activators may be used to improve curing speed in larger gaps, though this may affect ultimate bond strength and should be evaluated before use.

After curing for 24 hours at 22°C, the material exhibits a coefficient of thermal expansion of 100 × 10⁻⁶ K⁻¹ and thermal conductivity of approximately 0.1 W/(m·K). Electrical properties include a dielectric constant between 2 and 3.5 across frequencies from 0.1 to 10 kHz, dissipation factor below 0.02, volume resistivity ranging from 2 × 10¹⁵ to 10 × 10¹⁵ ohm·cm, surface resistivity between 10 × 10¹⁵ and 80 × 10¹⁵ ohms, and dielectric breakdown strength of about 25 kV/mm.

Lap shear strength after 24 hours at 22°C typically ranges from 20 to 30 N/mm² on grit blasted steel, 15 to 22 N/mm² on aluminum, 4 to 12 N/mm² on zinc dichromate, 6 to 20 N/mm² on ABS and PVC, 5 to 20 N/mm² on polycarbonate, and 5 to 15 N/mm² on phenolic, neoprene and nitrile rubber. Tensile strength values on steel range from 12 to 25 N/mm², while Buna-N rubber typically achieves 5 to 15 N/mm² after full cure. Peel strength on degreased steel is generally below 0.5 N/mm. After 30 seconds cure at 22°C, Buna-N tensile strength can reach at least 6.0 N/mm².

Environmental resistance testing shows the adhesive retains strength after prolonged exposure to motor oil at 40°C, gasoline, isopropanol, ethanol, Freon TA and 1,1,1 trichloroethane at room temperature. Performance under heat and humidity conditions indicates gradual strength reduction at elevated temperatures such as 60°C, 80°C and 100°C, while maintaining reasonable retention under moderate conditions. When exposed to 95% relative humidity at 40°C, strength retention varies depending on substrate, with polycarbonate showing improved resistance compared to some metals.

For best bonding performance, surfaces should be clean and free from grease or contaminants. The adhesive performs optimally in thin bond gaps of approximately 0.05 mm. Excess cured material can be removed using suitable cleanup solvents such as nitromethane or acetone. The product should be stored in its original unopened container in a dry environment at temperatures between 2°C and 8°C. Storage below 2°C or above 8°C may affect product characteristics. The adhesive is not recommended for use in pure oxygen or oxygen-rich systems and should not be used with strong oxidizing agents. Technical values provided represent typical properties and are intended for reference purposes.