COMPOSITE SOUND ABSORBING MATERIAL AND METHOD OF ITS PRODUCTION Russian patent published in 2017 - IPC B32B7/00 

FIELD: technological processes.

SUBSTANCE: method comprises the preparation of a foamed polyurethane composition by mixing a prepolymer and polyisocyanate groups, forming a back portion of a sound absorbing material in the form of a layer of a polyurethane composition having the thickness from 5 to 50% of the total thickness of the sound absorbing material by filling the lower part of the tool with the mentioned composition, followed by holding the layer of the polyurethane composition for 20 to 60 minutes in the temperature range from 20 to 80°C, applying a fibre material with the thickness from 30 to 90% of the total thickness of the sound absorbing material to the mentioned layer, filling the tool with the polyurethane composition to form the front and side portions of the sound absorbing material, in such a quantity so as to provide the thickness of the front portion of the sound absorbing material from 5 to 50% of the total thickness of the sound absorbing material, as well as the thickness of each side portion of the sound absorbing material from 5 to 20% of the total thickness of the sound absorbing material, followed by exposure of the total volume of the composition at a temperature from 20 to 80°C for 20 to 120 minutes. The sound absorbing material obtained by this method is also proposed.

EFFECT: simplifying the technological process of manufacturing sound-absorbing material, increasing the sound absorption coefficient, reducing moisture absorption, preserving the specified form of material during operation.

4 cl, 3 dwg, 2 tbl, 3 ex