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LOCTITE 574 is a medium strength anaerobic flange sealant based on dimethacrylate ester technology. It is a one component orange thixotropic paste that cures in the absence of air when confined between rigid metal flanges. The product is designed to seal close fitting joints and provides immediate resistance to low pressure after assembly. It is commonly used as a form-in-place gasket for gearboxes, engine housings and other rigid metal flange connections where reliable leak prevention and vibration resistance are required.
LOCTITE 574 is an anaerobic acrylic based sealing compound formulated with dimethacrylate ester chemistry and supplied as a single component orange paste requiring no mixing prior to use. The material exhibits thixotropic behavior which reduces migration after application and ensures accurate placement on flange surfaces. It cures when air is excluded between closely fitting rigid metal faces and is specifically developed for sealing flanged joints with minimal gap. The product provides medium strength sealing performance and offers resistance to low pressures immediately after flange assembly. The uncured material has a specific gravity of approximately 1.1 at 25°C. Brookfield viscosity measured at 25°C using spindle 6 at 2.5 rpm ranges from 70,000 to 120,000 mPa·s and at 20 rpm ranges from 23,000 to 35,000 mPa·s. Flash point information should be referenced from the Safety Data Sheet. The product also exhibits fluorescence under UV light which assists in inspection and quality control verification. Cure performance depends on substrate type, bond gap, temperature and use of activators. Strength develops more rapidly on active metals such as steel compared to less reactive substrates like aluminum. Smaller bond gaps promote faster cure speed, while larger controlled gaps may slow strength development. Elevated temperatures accelerate curing, whereas lower temperatures reduce reaction rate. When cure speed is insufficient or larger gaps are present, the use of activators such as SF 7649 or SF 7471 can improve curing performance. After 24 hours curing at 22°C, compressive shear strength on steel pins and collars is at least 6.0 N/mm². Lap shear strength on grit blasted steel is approximately 8.5 N/mm², and tensile strength according to ISO 6922 on grit blasted steel is approximately 5 N/mm². The cured material has a coefficient of thermal expansion of about 80 × 10⁻⁶ K⁻¹, thermal conductivity of approximately 0.1 W/(m·K), and specific heat of around 0.3 kJ/(kg·K). Environmental resistance testing after one week cure at 22°C indicates stable strength retention under elevated temperature exposure. Heat aging at 120°C and 150°C shows gradual reduction in mechanical strength depending on exposure duration. Chemical resistance testing demonstrates good retention of strength after exposure to motor oil at 125°C, moderate retention in gasoline at room temperature, and stable performance in water/glycol mixtures at elevated temperatures. These tests represent strength retention and not direct sealing performance. For optimal performance, flange surfaces should be clean and free from grease or contamination before application. The product is intended for close fitting flanges with gaps up to approximately 0.25 mm. It may be applied manually as a continuous bead, as a rolled film, or by screen printing to one flange surface. For gaps greater than 0.125 mm when using a roller application method, coating both flange surfaces is recommended. Low pressure testing below approximately 0.5 MPa may be performed immediately after assembly to confirm complete sealing prior to full cure. Flanges should be tightened promptly after assembly to avoid misalignment. The product is not recommended for use in pure oxygen or oxygen enriched systems and should not be selected as a sealant for chlorine or other strong oxidizing agents. Compatibility should be verified before use on thermoplastic materials. When aqueous cleaning systems are used prior to bonding, compatibility between cleaning solution and adhesive should be confirmed to avoid interference with curing performance. Recommended storage temperature is between 8°C and 21°C in the original unopened container. Storage below 8°C or above 28°C may adversely affect product properties. The technical data provided represent typical performance values for industrial reference and users are advised to conduct application specific validation before production use.
Product Type: Medium strength anaerobic flange sealant
Technology: Dimethacrylate ester acrylic technology
Appearance: Orange thixotropic paste
Component System: Single component (no mixing required)
Curing Mechanism: Cures in the absence of air when confined between rigid metal flanges
Specific Gravity @ 25°C: Approximately 1.1
Compressive Shear Strength (24 hrs @ 22°C): ≥ 6.0 N/mm²
Recommended Gap Size: Suitable for close fitting flanges up to approximately 0.25 mm
