Need to know
A high sound absorption capacity of the materials corresponds to a mild sound insulating capacity of the material, given their low specific weight. Therefore a good sound-absorbing material usually has little soundproofing power and vice versa. The absorption by porosity (i.e. materials with open cells or semi-open cells) is generally high at medium and medium-high frequencies, while a significant damping of low frequency requires the use of high thicknesses of porous material but especially a greater specific weight of the product that can be obtained from the bonding a sound absorbing layer to a loaded mass.
POLYURETHANE FOAM is a polymer that has very good sound absorption properties thanks to its open-cell composition. It is easy to use both for filling spaces between one wall and another, and for dampening the sound waves within a room. If, however, you need to prevent the escape of noise produced inside the room itself (for example from an engine compartment), an insulating product is needed, and therefore it is necessary to increase the specific weight of the polyurethane foam with a sheet (or two) of loaded rubber (mass). To get the most out of insulation, it is necessary to apply the soundproofing product to all surfaces of the room in question, including the ceiling, through precise bonding with another anchor using special fastening systems that prevent the product from detaching due to weight, temperature changes, or the loss of consistency of the product over time.
POLYESTER FIBRE AND GLASS FIBRE
Two new products, “FONOX Polyfiber” and “FONOX Glassfiber”, were recently introduced for the sound insulation of engine rooms. The first consists of layers of thermo-bonded polyester that, unlike polyurethane foam, does not “crumble” over time, and therefore remains active and effective for much longer. The second consists of a layer of 100% glass fibre. Both are finished with an aluminium film or a glass fibre fabric and, depending on usage, can be bonded with a sheet of loaded rubber (mass) to optimise the dampening effect.