Title: Reticulated polyurethane foams and process for their production

 Number/Link: US3171820

Applicant/Assignee: Scott Paper Co.

Publication date: 2-03-1965

“Gist”: PU foams are reticulated by hydrolysis or explosion.

Why it is interesting:   Reticulated foams are foams from which the membranes have been removed so that only a three dimensional network of strands or ‘struts’ remains. These materials are commercially available in different grades of stiffness and porosity and are useful in applications such as filtering, sound absorbing, padding and the like. The current invention – filed in 1964 but a ‘continuation’ of an application filed in 1956- teaches the two processes to reticulate PU foam still in use today. The first process uses an aqueous NaOH solution to hydrolyse the cell membranes, in the second process a foam block is brought in an autoclave together with an explosive gas mixture (e.g. a mixture of oxigen and acetylene) which is then made to explode using a spark plug. When executed correctly the explosion removes all cell membranes leaving the struts intact. ‘Explosive recticulation’ is one of my all-time favorite PU inventions: simple, yet very effective and very courageous. In the current culture of hyper-safety where employees have to report paper-cuts, inventions like this are no longer possible.

A recticulated polyurethane foam