Surface Preparation - polyolefin primer. Ideal for difficult-to-bond plastics. Lcotite 770 is a primer used to make polyolefin and other low-energy surfaces suitable for bonding with Loctite instant adhesives. The cured performance of Loctite instant adhesives is ensured on such treated surfaces. It is only recommended for difficult-to-bond substrates which include polyethylene, polypropylene, polytetrafluoroethylene (PTFE) and thermoplastic rubber materials. Loctite 770 is not recommended in assemblies where high peel strength is required.