Loctite LOCTITE SF 770 (10-ml-Btl)

LOCTITE® 770™ Polyolefin Primer

Overview

LOCTITE® 770™ Polyolefin Primer is a surface preparation primer designed to improve the bondability of low-surface-energy plastics when used with LOCTITE® cyanoacrylate adhesives. Specifically formulated for difficult-to-bond materials such as polyethylene (PE), polypropylene (PP), polytetrafluoroethylene (PTFE), and thermoplastic rubber (TPR), the primer modifies the substrate surface to significantly improve adhesive performance and bond strength. It is widely used in aerospace, industrial, automotive, electronics, and manufacturing assembly applications.

Key Technical Characteristics

• Product Type: Cyanoacrylate surface primer
• Technology: Polyolefin bonding primer
• Chemical Type: Aliphatic amine
• Carrier Solvent: n-Heptane
• Appearance: Transparent to slightly hazy liquid
• Active Ingredient Concentration: 0.07-0.13%
• Specific Gravity: 0.68
• Viscosity: 1.25 cP
• Drying Time: ?30 seconds
• On-Part Life: ?8 hours
• UV Detection: Fluorescent under UV light

Core Performance Benefits

• Improves adhesion on low-surface-energy plastics
• Enables bonding of materials typically difficult to bond with cyanoacrylates
• Accelerates cyanoacrylate cure speed
• Provides rapid surface preparation and drying
• Enhances bond strength on polyolefins and fluoropolymers
• Simple application process with minimal material usage
• UV fluorescence allows verification of primer coverage
• Compatible with a wide range of LOCTITE® cyanoacrylate adhesives

Typical Applications

• Polyethylene (PE) bonding
• Polypropylene (PP) assembly
• PTFE component bonding
• Thermoplastic rubber (TPR) assembly
• Aerospace plastic component bonding
• Industrial plastic assemblies
• Electronic device manufacturing
• Automotive plastic component assembly

Material Engineering & Design Features

LOCTITE® 770™ is formulated to chemically modify low-energy plastic surfaces, allowing cyanoacrylate adhesives to achieve significantly improved wetting, adhesion, and bond performance. Without surface treatment, materials such as polyethylene and polypropylene often exhibit poor bonding characteristics due to their low surface energy.

The primer is particularly effective on:

• Polyethylene (PE)
• Polypropylene (PP)
• Polytetrafluoroethylene (PTFE)
• Thermoplastic Rubber (TPR)
• Other difficult-to-bond plastics

Typical lap shear performance after treatment includes:

• Polypropylene + LOCTITE® 406™: 3-10 MPa
• Polypropylene + LOCTITE® 496™: 2-7 MPa
• Thermoplastic Rubber + LOCTITE® 406™: 2-6 MPa
• PTFE + LOCTITE® 406™: 1-6 MPa

In addition to improving adhesion, the primer acts as an activator that accelerates cyanoacrylate fixture and cure speeds, with many assemblies fixturing in less than 5 seconds.

Installation & Handling

• Apply at ambient temperature
• Can be applied by:
  • Spraying
  • Brushing
  • Dipping
• Apply only a thin coating and avoid excessive primer application
• Allow primer to dry completely before adhesive application
• Presence of primer can be verified using a 365 nm UV inspection lamp
• When bonding polyolefins to higher-energy materials, apply primer only to the polyolefin surface
• Apply cyanoacrylate adhesive within 8 hours of primer application

Environmental & Compliance Notes

• Contains highly flammable solvent
• Store in unopened containers in a dry location
• Recommended storage temperature: 8°C to 21°C
• Avoid storage below 8°C or above 28°C
• Solvent may affect certain plastics and coatings; compatibility testing is recommended
• Not recommended for pure oxygen or oxygen-enriched systems
• Refer to Safety Data Sheet (SDS) before use

Key Advantages

• Transforms difficult-to-bond plastics into bondable surfaces
• Improves cyanoacrylate adhesive performance dramatically
• Accelerates assembly and production processes
• Fast drying and easy application
• UV-detectable coverage enhances quality control
• Compatible with multiple LOCTITE® cyanoacrylate systems
• Supports reliable bonding of PE, PP, PTFE, and TPR materials
• Widely used in aerospace, industrial, automotive, and electronics manufacturing