| 摘要 |
<p>A glazing unit is described comprising a composite glazing panel having a pair of vitreous sheets (21, 22) with an intervening layer (23) of polymeric material sandwiched therebetween. The polymeric material layer has viscoelastic properties such that the critical frequency of coincidence (or the lower or lowest critical frequency of coincidence if there is more than one) of the panel ¢"the coincidence frequency (.PHI.p) of the panel"! is greater than the critical frequency of coincidence of a notional monolithic vitreous sheet ¢"the coincidence frequency (.PHI.m) of the equivalent monolith"! which monolithic sheet is of the same shape and area as the panel and has a mass equal to the total mass of vitreous material in the panel. An adhesive material (29, 30) is in contact with each vitreous sheet. The adhesive material exhibits, at 20.degree.C, an elongation of not more than 12.5% when subjected to a tensile stress of 0.1 MPa, as measured according to ISO 8339. There is such adhesive material in contact with an outer face of at least one of said sheets (22), at a marginal portion thereof. The arrangement enables more secure fixing of the composite panel in the unit. (Fig. 2)</p> |
