MULTILAYER SOUND-ABSORBING MATERIAL Russian patent published in 1994 - IPC

FIELD: decorative acoustic materials for lining walls in public buildings, cabs of various vehicles. SUBSTANCE: multilayer sound-absorbing material consists of main layer made of low- shrinkage pvc fibers with surface density of 2000-4000 g/sq.m, and additional layer which is three-layer bulky material of polyamide with polyester fibers with layer ratio in thickness, mm: main layer 20-40; additional layer 3-10; Needle punching is effected from the side of main layer to depth of 2/3 of material thickness. EFFECT: higher efficiency. 3 tbl