EP 0720143 B1 20000906 - Absorbing material for acoustic waves
Title (en)
Absorbing material for acoustic waves
Title (de)
Absorbierendes Material für Schallwellen
Title (fr)
Matériau absorbant les ondes acoustiques
Publication
Application
Priority
FR 9415646 A 19941226
Abstract (en)
[origin: EP0720143A1] Absorbing compsn. for sound waves comprising: (a) a structural material (I) imparting limited rigidity to the compsn.; and (b) an absorbing material (II) having a lesser rigidity than the compsn. in order to dissipate the sound wave energy; is characterised in that (I) is a thixotropic material constituted by macromolecules (III) carrying electric charges of a same sign and having no mutual covalent bonds, the electric charges being neutralised by small and mobile counter ions. Pref. (I) is a plastic porous material impregnated with the thixotropic material. At least part of the counter ions carry hydroxyl groups allowing hydrogen bonding. (III) is (i) an acid polymer, such as polyacrylic acid, polystyrenesulphonic acid and carboxycellulose, the counter ions being derived from organic bases, such as ammonia, aminoalcohols (mono-, di- or tri-ethanol amine) and quat. ammoniums; or (ii) a basic polymer, such as polyethylene-imine, the counter ions being derived from carboxylic acids, such as citric acid, propionic acid, glycolic acid and sebacic acid, sulphonic acids or phosphonic acids.
IPC 1-7
IPC 8 full level
G10K 11/16 (2006.01); G10K 11/162 (2006.01)
CPC (source: EP)
G10K 11/162 (2013.01)
Designated contracting state (EPC)
CH DE FR GB IT LI SE
DOCDB simple family (publication)
EP 0720143 A1 19960703; EP 0720143 B1 20000906; DE 69518730 D1 20001012; FR 2728715 A1 19960628; FR 2728715 B1 19970131
DOCDB simple family (application)
EP 95402932 A 19951222; DE 69518730 T 19951222; FR 9415646 A 19941226