MULTILAYER PERFORATED SOUND ABSORBER Russian patent published in 2017 - IPC G10K11/168 

FIELD: chemistry.

SUBSTANCE: sound absorber contains a thermoformable absorber and a microperforated film that are connected to each other. The microperforated film consists of two-layer more high-melting layer of polymer material equipped with a specific hole geometry, and the second layer of the polymer material, more low-melting compared with the first layer of the polymer material. The low-melting layer of the polymer material includes an intermediate layer of the absorber components and low-melting polymer material adjacent to the absorber, and the ratio of hydraulic resistance of the covering layer of the layer of more high-melting polymer material and the intermediate layer to the absorber is from 1:3 to 1:30, and the total hydraulic resistance R of the absorber is in the range of R=800 Nsm^-3 to R=8000 Nsm^-3. The first high-melting layer of the polymer material includes polyamide, polyethylene terephthalate, polyetherimide, polysulfone, polyethersulfone and/or polyetheretherketone. The second layer of the polymer material, more low-melting than the first layer of the polymer material, contains polyethylene and polypropylene, including their composition and copolymers, also with polyamides and/or polyesters; polyurethane resins; melamine resins and/or epoxy resins.

EFFECT: improving the efficiency of noise absorption.

15 cl, 2 dwg