ESPUMA DE CELULAS ABIERTAS EN BASE A PLASTICOS CON ELEVADO PUNTO DE FUSION

Espuma en base a un material termoplástico resistente a altas temperaturas, seleccionado del grupo compuesto por polieterimidas, polietersulfonas, polisulfonas, polietercetonas, polieteretercetonas, poliéter cetona cetonas, polietersulfonamidas y sus mezclas, caracterizada porque la espuma presenta una estructura de células abiertas, con lo que la espuma presenta una abertura de las células de al menos un 75%, preferentemente al menos de un 85%, de manera especialmente preferida de al menos un 90%. An open-cell foam comprises high-temperature-resistant thermoplastic. The foam has an open-cell structure. Independent claims are also included for: (A) a process for producing an open-cell foam comprising melting a thermoplastic or mixture having thermoplastic, giving a melt, mixing the melt with blowing agent(s) under pressure, foaming the melt having blowing agent through extrusion into the open atmosphere, and carrying out the foaming at a melt temperature that is higher by 2-20, preferably 2-10[deg]C than the temperature where closed-cell foam is formed; and (B) a process for producing foam sheets for use in sound deadening comprising producing sheets composed of an open-cell foam, in particular through foaming the melt via extrusion into the free atmosphere from a slot die, shaping in a calibrator, giving sheets with wide and narrow outer surfaces, dividing the resultant sheets parallel to their wide surfaces, giving two portions of the sheets having new inner wide surface, and adhesive-bonding the two portions obtained through division of the sheets. The surfaces adhesive-bonded to one another were previously the outer wide surfaces so that location of the new inner side surfaces is on the outside.