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LOCTITE 542 is a medium strength anaerobic thread sealing adhesive formulated with dimethacrylate ester acrylic technology. It is a single component brown liquid with low viscosity that cures in the absence of air when confined between metal threads. The product is specially designed for locking and sealing metal pipes and fittings, preventing leakage and loosening caused by vibration and shock. Its thixotropic behavior minimizes migration after application, making it suitable for hydraulic and pneumatic threaded assemblies.
LOCTITE 542 is an anaerobic thread sealant supplied as a one component brown liquid that requires no mixing before use. The product cures when air is excluded between closely fitting metal threads and develops medium strength locking and sealing performance. It is designed primarily for metal pipe fittings and threaded assemblies where resistance to vibration and leakage is required. The material exhibits thixotropic properties to reduce run-off after application. The specific gravity at 25°C is approximately 1.06. Brookfield viscosity at 25°C ranges from 1,200 to 2,750 mPa·s at 2.5 rpm and 400 to 800 mPa·s at 20 rpm. According to EN 12092 testing at 25°C after 180 seconds, viscosity at shear rate 277 s⁻¹ is approximately 150 mPa·s. Flash point information should be referenced from the Safety Data Sheet. Cure speed depends on substrate, temperature, bond gap and use of activator. Strength develops progressively on steel, brass, stainless steel and zinc dichromate surfaces. Higher temperatures accelerate curing, while lower temperatures slow the process. When cure speed is insufficient or larger thread gaps are present, activators such as SF 7471 or SF 7649 may be used to improve performance. After 24 hours at 22°C, breakaway torque on M10 steel nuts and bolts is approximately 15 N·m, prevail torque around 9 N·m, breakloose torque about 25 N·m and maximum prevail torque approximately 25 N·m. Compressive shear strength on steel pins and collars is at least 6.5 N/mm². The cured material has a coefficient of thermal expansion of approximately 80 × 10⁻⁶ K⁻¹, thermal conductivity around 0.1 W/(m·K) and specific heat about 0.3 kJ/(kg·K). Environmental testing after one week cure at 22°C shows good strength retention under exposure to motor oil at 125°C, unleaded petrol, brake fluid, water/glycol mixtures, ethanol and acetone, with minor reduction under prolonged solvent exposure. Heat aging tests at 120°C and 150°C demonstrate gradual strength reduction depending on exposure duration. Hot strength performance varies with temperature, and curing can be accelerated at 40°C while reduced at 5°C. For assembly, threads should be clean and dry before application. A 360° bead should be applied to the leading threads of the male fitting, leaving the first thread free. For larger threads or gaps, material may also be applied to the female threads. Fittings should be assembled and tightened according to manufacturer recommendations. Properly tightened joints will seal instantly to moderate pressures, while full pressure and solvent resistance is achieved after approximately 24 hours cure. For disassembly, standard hand tools are typically sufficient. In cases of large diameters or long engagement lengths, localized heating to approximately 250°C may be required before disassembly. Cured material can be removed using suitable solvents combined with mechanical abrasion. Recommended storage temperature is between 8°C and 21°C in the original unopened container. Storage below 8°C or above 28°C may affect product properties. The product is not recommended for use in pure oxygen or oxygen rich systems and should not be used with strong oxidizing materials. Compatibility with plastics and aqueous cleaning systems should be verified before use. Technical values provided represent typical performance data for industrial reference
Product Type: Medium strength anaerobic thread sealing adhesive
Technology: Dimethacrylate ester acrylic technology
Appearance: Brown liquid with low viscosity
Component System: Single component (no mixing required)
Curing Mechanism: Cures in the absence of air when confined between metal threads
Specific Gravity @ 25°C: Approximately 1.06
Breakaway Torque (M10 Steel, 24 hrs @ 22°C): ~15 N·m
Compressive Shear Strength (Steel, 24 hrs): ≥ 6.5 N/mm²
