| 摘要 |
<p>In laminated glazing used for acoustic insulation and comprising two or more rigid transparent sheets and one or more insulating and/or strengthening plastic films, the novelty is that the plastic film is associated with a film having ordinary acoustic quality, i.e. (a) when this film is 2 mm. thick and is assembled with two 4 mm. thick glass sheets to form a laminated slab of 9 cm. length and 3 cm. width and subjected to impact, the primary mode resonance frequency (fc) differs by more than 35% from that of a 4 mm. thick monolithic glass slab of the same length and width; or (b) when the film is max. 1 mm. thick and is assembled with two 2.1 mm. thick glass sheets to form a laminated plate, the measured acoustic attenuation index deviates, for frequencies greater than 800 Hz, by more than 6 dB from a reference index increasing from 9 dB per octave up to 2000Hz and by more than 3 dB per octave at higher frequencies. Also claimed is a film for insertion in laminated glazing to provide insulating and/or strengthening properties, the film being associated with a film having ordinary acoustic quality as described above. Pref. the film having ordinary acoustic quality is a standard polyvinylbutyral film and is separated from the insulating and/or strengthening plastic film by an impervious thin film pref. based on polyethylene terephthalate.</p> |
