Reticulated foam

The reticulation is a post-treatment of foam materials to obtain a liquid, air or gas permeability.

History

The process was patented in plastics technology in 1965 by the company Scott Paper & Co in the U.S.. Permeable to liquids and gases is referred to as reticulated polyurethane. This translucent plastics can be used as a mechanical filter. By coating the surface with activated carbon to further filter types can be implemented.

Methods

When the reticulation are caused by the production thin " skin " between the individual foam cells, which make the product impermeable to air, destroyed.

Water reticulation

A mixture of gaseous, combustible materials (eg explosive gas ) is mixed simultaneously with the firing pulse of about 185 ° C hot steam ( under pressure). It is initiated an exothermic reaction and those caused by the explosive reaction released heat according to the equation

The perforation of the foam cell walls and their selective sintering to a web thickness of the structural substance of the foam. Here, the flame spread of S. G. hard reticulation thwarted. The gas mixture also contains amounts of other gases, and a propane and butane.

The heat released heats the exact water vapor to be dispensed to continue and thus it is transferred specifically to the foam. This can be used if you white or very light foams without any discoloration by sg " Traces of burning " wants reticulate. In addition, you can determine the thickness of the web, which is formed in the thermal reaction by fusion of the cell web, as it is requested by these targeted input of water vapor. The desired strength and especially the formation of the cell web is different from customer to customer. ( Must be calculated for each foam type), depending on the filling pressure and gas mixture is a uniform distribution of the combustible gas mixtures in which to retikulierenden ingot reached.

Health hazards vaporous pollutants are produced in this Retikulierprozeß with addition of water not because the foams are not exposed to high temperatures and open flame exposure.

If the form in which the hydrogen - air-water - oxygen mixtures are ignited, raised above 2.5 bar addition, occur slightly above the stoichiometric composition " discontinuities " on. However, the explosions take no violent history and there is also no noticeable congestion / compression of the combustion fumes instead, which in turn would result in an increase in pressure. The flame education through the existing water is or can be reliably prevented. In multiple ignition of combustible mixtures described reaction is always triggered despite water content. But if by any unforeseen impacts be no ignition, it can be a gas-flow and the vacuum system removes the existing unexploded Retikulieratmosphäre and replaced with normal atmosphere.

The method of INT.TT Muetzelfeldt is only when the foam is somewhat " deposited ". It arises in the other hardly any smell. It only works optimally when the ester or Etherschaumstoff before insertion is completely dry to the reaction vessel and is well matured ( ie older than a week ). A certain type of silicone should be used in the foam process, especially when large-pore polyester (< 15ppi ).

Brittle fracture - reticulation

In this process, the closed cross-linked cells are mechanically opened at least partially by the foam is cooled to a temperature below its embrittlement temperature TV and a subsequent mechanical stress is subjected.