PU to Metal Bonding Agent 840

1. Description

840 a one-coat surface treatment used to affix castable and millable polyurethane elastomers to metals and other rigid substrates. It is composed of a mixture of polymers and resins dissolved in an organic solvent system

2. Features and Benefits

● Environmentally Resistant – provides excellent resistance to water, salt spray, a variety of solvents and other environmental conditions.

● Convenient – requires no primer, reducing labor and costs.

3.Typical Properties

● Appearance:  Clear to Slightly Hazy Amber Liquid

● Viscosity, cps @ 25°C (77°F) Brookfield LVT Spindle 3, 60 rpm:  400-1000

● Density(kg/m3):  950.0 - 990.0

● Solids Content by Weight, %:  18-21

● Flash Point (Seta), °C:  2-15

● Solvents:  Toluene, Trichloroethylene, Isopropanol, Ethanol

4. Application

● Surface Preparation – Thoroughly clean metal surfaces prior to application. Remove protective oils, cutting oils and greases by solvent degreasing or alkaline cleaning. Remove rust, scale or oxide coatings by suitable chemical or mechanical cleaning methods.

● Mixing – No agitation is required before or during use. If dilution is needed, use either a 1:1 isopropanol: toluene blend (by volume) or glycol ether solvents. Note proper dilution for the various application methods is best achieved by experience.

● Applying – Apply 840 by brush, dip, spray, roll coat or any method that gives uniform coating and avoids excessive runs and tears. Regardless of application method, dry film thickness of 840 should be 15-35 micron. 840 is also tolerant of processing conditions such as long prebakes.

● Drying/Curing – Allow coated parts to air-dry for at least 60 minutes at room temperature for complete solvent evaporation. The film may be force dried at higher temperatures for shorter periods of time. Drying for 15 minutes at 121°C (250°F) has no harmful effect on performance.

● To enhance cohesive strength, bake coated inserts a minimum of 2 hours at 121°C (250°F). Large inserts will require longer baking time at 121°C (250°F) to negate the heat sink effect.

● Parts coated with 840 may be vulcanized immediately after air-drying.

● Molding procedures that are used with heat vulcanizing urethane elastomers can be used with 840 adhesive. The cure time and temperature are the same as the process conditions required to vulcanize the urethane compound being molded. Best results are obtained with curing temperatures above 71°C (160°F).

● Cleanup – Use alcohol, such as isopropanol, or a chlorinated solvent, such as trichloroethylene, to clean up small spills.

5.Shelf Life/Storage

Shelf life is one year from date of shipment when stored at 21-27°C (70-80°F) in original, unopened container. Do not store or use near heat, sparks or open flame.