New water-based adhesive
German adhesive manufacturer Kommerling, has produced a new water base adhesive system, Koracoll 3310. It is easy to introduce into the factory, as the new PUR-Dispersion adhesive can be applied to the upper while conventional solvent based primer/adhesive can continue to be used on the sole. Progress can therefore be made stage by stage without changing the complete system overnight.
Drying time is 30-40 minutes at room temperature but this can be reduced to 5-15 minutes through a drying tunnel. Setting contact and initial bond strength is said to be very good and the adhesive can be applied by hand or machine. Consumption per shoe using solvent base adhesives is 45-60grms, while with PUR-Dispersion, it is claimed to be 4.5-10grms, which off-sets any additional adhesive cost.
The advantages are said to lie in better working conditions, protection of the environment and meeting European emission limits of 37.5grms of solvent per shoe due in November 2005.
