LOCTITE SF 770 Adhesive Primer for Polyethylene, Polypropylene, PTFE and Thermoplastic Rubber

LOCTITE SF 770 Adhesive Primer Benefits

LOCTITE SF 770 Adhesive Primer expands the range of substrates that can be bonded with cyanoacrylate adhesives. Untreated polyolefins and fluoropolymers have low surface energy, which can prevent an instant adhesive from wetting the material effectively. Applying SF 770 creates a more suitable bonding surface without mechanical abrasion, plasma equipment or complicated chemical treatment.

The transparent to slightly hazy liquid has an extremely low viscosity, allowing it to spread rapidly across small components, molded parts and detailed bonding areas. It can be applied by brushing, spraying or dipping, making it suitable for manual assembly, repair work and controlled industrial production.

The primer also fluoresces under ultraviolet light. Production teams can use a compatible 365 nm UV inspection lamp to confirm that the required bonding area has been treated, supporting process control and reducing the risk of missed primer application.

Applications for LOCTITE SF 770 Adhesive Primer

LOCTITE SF 770 Adhesive Primer is recommended for difficult-to-bond materials such as polyethylene, polypropylene, PTFE and thermoplastic rubber. Typical applications include plastic housings, molded components, caps, connectors, seals, tubing parts, appliance components, automotive trim, electronic assemblies and industrial products made from low-energy polymers.

When a polyolefin component is bonded to steel, aluminum or another easier-to-bond material, the primer should normally be applied only to the polyolefin surface. The selected LOCTITE cyanoacrylate adhesive is then applied after the primer has completely dried.

The product is intended specifically for use with compatible LOCTITE instant adhesives. It is not an independent adhesive and does not create a bond without a cyanoacrylate product. Henkel does not recommend it for assemblies requiring high peel strength, so flexible joints and heavily peel-loaded designs should be evaluated carefully.

LOCTITE SF 770 Adhesive Primer Technical Properties

The product is based on an aliphatic amine carried in isopropyl acetate. Its typical specific gravity is approximately 0.87 at 23°C, while published viscosity is about 0.62 mPa·s at 25°C. This extremely low viscosity supports rapid wetting and thin, uniform application.

Typical drying time is approximately nine seconds on steel or polypropylene and eight seconds on polyethylene at 23°C. The treated surface has an on-part life of up to eight hours when it remains clean and uncontaminated. For the best results, Henkel recommends applying the instant adhesive and assembling the parts immediately after the primer has dried.

Published testing demonstrates that polypropylene treated with SF 770 can achieve strong block-shear performance when bonded with selected LOCTITE cyanoacrylate adhesives. Actual results depend on the polymer grade, adhesive selection, surface condition, joint design, temperature, humidity and production process.

How to Apply LOCTITE SF 770 Adhesive Primer

Clean the bonding area and remove oil, dust, moisture, mold-release residue and loose contamination. Apply a thin coating by spraying, brushing or dipping at room temperature. Avoid excessive application because a heavy primer layer does not normally improve bonding performance.

Allow the solvent to evaporate completely, then apply the selected LOCTITE instant adhesive and assemble the components. Keep the prepared surface protected from contamination. The solvent may affect certain plastics, paints or coatings, so compatibility testing should be completed before production use.

Why Choose LOCTITE SF 770 Adhesive Primer?

LOCTITE SF 770 Adhesive Primer provides fast drying, simple application, UV inspection and improved instant adhesive bonding on challenging low-energy plastics. It is a practical surface-preparation solution for manufacturers working with polyethylene, polypropylene, PTFE and thermoplastic rubber components.

The product is highly flammable and must be handled with suitable ventilation and ignition control. Store unopened containers in a dry location between 8°C and 21°C. Review the official Henkel LOCTITE SF 770 Technical Data Sheet and the correct current Safety Data Sheet for the supplied IDH number before use. Explore our adhesive activators and primers for additional industrial surface-treatment solutions.