ABSTRACT
Latex foam is manufactured by different processes. Most important among these are the Dunlop process and the Talalay process. The Dunlop process is done both in batch and continuous operations. Most small-scale foam rubber manufacturers use the batch process for foam production. In the Dunlop process, sparse quantities of soluble alkali metal silicofluoride and zinc oxide are used as gelling agents. Two types of gelling system are used in foam production, namely heat gelling and delayed-action gelling. The most important type of heat gelling system is the zinc oxide-ammonia salt system. A good delayed-action gelling agent can be easily incorporated in latex and will bring about gelation only gradually and after a reasonable time interval. In natural latex, which is a variable raw material, differences in gelling path are common even if the same formulations are used in gelling and foaming.
