What is Foam?

Flexible polyurethane foam is a cellular plastic formed by a chemical reaction. This involves the reaction of polyols (Ester, Ether, Polymer Polyols) with Toluene Diisocyanate (TDI) or Methylene Diphenyl Diissocyanate (MDI) and water. Various catalysts are added to control the gell and blow portion of chemical reaction and surfactants are also added to control the generation of foam . Various combinations of polyols can be utilized to alter a multitude of physical properties.  Additional chemicals can be added to control fire retardency, electrical resistance properties, micro-organism growth, hardness and cell structure. All the chemicals are mixed together in specific amounts and the foam reaction begins almost immediately. It’s been compared to bread/cake rising.

When the chemical reaction takes place the critical balance between the gell and blow portion of the reaction produces a solid 3 dimensional structure of bubbles which are shaped like dodecahedrons (12 sided cellular structures). Each of the 12 sides are pentagonal in shape. The pentagon consists of struts, which have a membrane or window stretched between them. At least one of the membranes in each cell is ruptured during the reaction to form open celled foam. A multitude of cells make up what is known as polyurethane foam.

Low density foams feature thin and brittle cell struts whereas high density foams 30kg or above (eg Dunlop Enduro foams) feature thick, resilient cell struts for superior durability. Conventional foams have a regular cell structure. Enduro High Resilience (HR) foams have an irregular cell structure with smaller and larger cells - this enhances comfort because HR foams compress more progressively.