LOCTITE SF 770 Polyolefin Primer is a fast-drying surface treatment designed to improve cyanoacrylate adhesive bonding on difficult, low-surface-energy plastics and elastomers. Officially known as LOCTITE 770, this ready-to-use primer prepares polyethylene, polypropylene, PTFE, and thermoplastic rubber for bonding with compatible LOCTITE instant adhesives. Its transparent to slightly hazy appearance, extremely low viscosity, and rapid evaporation support precise application in electronics, automotive components, appliances, medical devices, and industrial plastic assembly.

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LOCTITE SF 770 Polyolefin Primer Benefits

The main advantage of LOCTITE SF 770 Polyolefin Primer is its ability to condition substrates that normally provide poor adhesive wetting. Low-surface-energy materials can be difficult to join with standard instant adhesives because the liquid may not spread evenly. Applying a thin layer of primer changes the bonding interface and helps the selected LOCTITE cyanoacrylate develop more consistent adhesion.

The one-component formula requires no mixing, heating, or specialized curing equipment. It can be applied by brush, controlled dispensing, spraying, or dipping, depending on component shape and production volume. The primer also fluoresces under ultraviolet light, giving quality-control teams a convenient method for checking coverage before adhesive application.

LOCTITE SF 770 Polyolefin Primer Applications

This product is recommended for polyethylene, polypropylene, polytetrafluoroethylene, and thermoplastic rubber. Typical applications include molded plastic housings, clips, caps, seals, gaskets, tubing, appliance components, automotive trim, electronic enclosures, disposable device parts, and compact industrial assemblies. It can also support mixed-material bonding when a treated low-energy plastic must be joined to metal, rubber, or another compatible substrate.

Apply the primer only to the difficult-to-bond surface. When both parts are made from low-energy material, treat both bonding areas. Use it with a compatible LOCTITE cyanoacrylate selected according to joint gap, fixture speed, substrate type, temperature exposure, and mechanical loading. Because material formulations vary, production testing is essential before commercial approval.

LOCTITE SF 770 Polyolefin Primer Technical Properties

The primer uses aliphatic amine technology in an isopropyl acetate solvent. Typical published values include a specific gravity of approximately 0.87 at 23°C and viscosity of about 0.62 mPa·s at 25°C. Under stated laboratory conditions, drying time is approximately eight seconds on polyethylene and nine seconds on polypropylene or steel. The treated surface remains active for up to eight hours, although applying adhesive promptly after drying is recommended.

These values are typical reference data rather than guaranteed specifications. Actual performance depends on surface cleanliness, primer quantity, application method, substrate formulation, adhesive choice, temperature, humidity, joint design, and service conditions. Henkel does not recommend this primer for assemblies where high peel strength is a primary requirement.

How to Apply LOCTITE SF 770 Polyolefin Primer

Clean the bonding surfaces and remove oil, dust, moisture, mold-release agents, and loose contamination. Apply one thin, uniform coating to the low-energy substrate. Avoid pooling or excessive application because unnecessary primer may affect appearance or process consistency. Allow the solvent to evaporate completely, then dispense the selected LOCTITE instant adhesive and assemble the parts within the validated processing window.

Hold the components in alignment until sufficient fixture strength develops. Confirm compatibility with nearby paints, coatings, inks, and sensitive plastics before regular use. Provide effective ventilation, control ignition sources, wear appropriate personal protective equipment, and follow the current Safety Data Sheet during handling, storage, and disposal.

Why Buy LOCTITE SF 770 Polyolefin Primer?

LOCTITE SF 770 Polyolefin Primer offers a practical way to expand instant adhesive bonding to PE, PP, PTFE, and thermoplastic rubber. Its rapid drying, one-part convenience, UV fluorescence, and compatibility with professional LOCTITE cyanoacrylates support efficient production and dependable overall process quality control. Review the official Henkel product information before qualification, and explore our industrial adhesive primers for additional surface-preparation solutions.

industrial adhesive primers