Foamed materials using low boiling expanding agent - controlled accurately in quantity by two positive displacement pumps

摘要

The controlled feed of the expanding agent in a process for manufacturing foed material is effected by a positive displacement pump. The expanding agent is for pref. a liquid with a low boiling point. Pref. the expanding agent is supplied to the pump at practically constant pressure. One or more of the components for the foam are delivered at the same time to the pump. For pref. two pumps are used in series. The expanding agent is fed to the second pump behind the first, with the second pump having a different delivery from the first, so that the feed of the expander is effected. The expanding agent used is methylene chloride or "FREON" (RTM) and it is fed into a stream of polyol. Ensures the positive controlling of the flow of the fluid expanding agent with a low boiling point, so that flexible and rigid foam can be produced without pinholes.