Neoprene polychloroprene grades A & W are preferred when manufacturing solvent-based adhesives. The two main criteria which influence the polymer selection when designing an adhesive formula are crystallization rate and viscosity. Crystallization determines the rate of initial strength development. The faster the rate of crystallization, the faster the rate of strength development.

Viscosity influences the inherent strength of the adhesive film, the solution viscosity and solids content. Using a polymer with high viscosity or molecular weight gives improved film strength. However, lower solids content may need to be used in the formulation, raising the volatiles content. With lower molecular weight polymer promote higher solids content, but trade-off the ultimate film strength.

Neoprene WB is used to provide high gel content without adversely affecting adhesive rheology. It promotes good hot bond strength and is particularly suitable for use in applications where hot creep resistance is desirable. However, Neoprene WB has essentially no tack and it is essential to blend this grade with other Neoprene types in contact adhesives.

General Purpose Grades

• Neoprene AD 20: rapid crystallization rate.
• Neoprene W, WHV-100, WHV: moderate crystallization rate and wide viscosity range.
• Neoprene WRT: very slow crystallization and low viscosity.
• Neoprene WB: for higher gel content