PU To Metal Adhesive 840 Substitute For Chemlok 218 Cilbond 48 49 Thixon 422

1. Description

PU to Metal Adhesive 840 is a one-coat surface treatment designed to bond castable and millable polyurethane elastomers to metals and other rigid substrates. It consists of a blend of polymers and resins dissolved in an organic solvent system.
Equivalent to: Chemlok 218, Cilbond 48/49, Thixon 422.

2. Features and Benefits 

Environmentally Resistant – Offers superior resistance to water, salt spray, various solvents, and other environmental conditions.

Convenient – No primer is required, reducing labor and overall costs.

3. Typical Properties

4.Application

Surface Preparation – Thoroughly clean metal surfaces before application. Remove protective oils, cutting oils, and greases through solvent degreasing or alkaline cleaning. Eliminate rust, scale, or oxide coatings using appropriate chemical or mechanical methods.

Mixing – No agitation is required before or during use. If dilution is necessary, use a 1:1 isopropanol:toluene blend (by volume). Proper dilution for different application methods is best determined through experience.

Applying – Apply 840 by brush, dip, spray, roll coat, or any method that ensures a uniform coating while avoiding excessive runs and tears. The recommended dry film thickness of 840 is 15-35 microns, regardless of the application method. 840 is also compatible with extended prebake conditions.

Drying/Curing – Allow coated parts to air-dry for at least 60 minutes at room temperature to ensure complete solvent evaporation. Forced drying at higher temperatures is possible for shorter durations. Drying at 121°C (250°F) for 15 minutes does not negatively affect performance.
For improved cohesive strength, bake coated parts for at least 2 hours at 121°C (250°F). Larger inserts may require longer baking times to counteract the heat sink effect.
Parts coated with 840 can be vulcanized immediately after air-drying. Molding procedures used for heat-vulcanizing urethane elastomers are applicable to 840, with the same curing time and temperature as required for the urethane compound being molded. Best results are achieved when curing temperatures exceed 71°C (160°F).

Cleanup – Use alcohol (e.g., isopropanol) or a chlorinated solvent (e.g., trichloroethylene) for cleaning up small spills.