LAMINATED GLAZING UNIT HAVING MECHANICAL STRENGTH AND ACOUSTIC INSULATION PROPERTIES, POLYMERIC FILM AND METHOD OF DETERMINING THE TEAR STRENGTH

摘要

A laminated window (1) comprises two sheets of glass (10, 11) and an interpolated sheet (12) of a material adequate for acoustic insulation. The interpolated sheet has an adequate thickness (e) to satisfy the criterion of minimal strength. The thickness (e) of the interpolated sheet is at least equal to erefasteriskJref/Jc (claimed) where: (a) Jc is the critical energising value and representative of the energy needed for the propagation of a fissure initialised in the interpolated sheet; (b) Jref is the reference critical energising value corresponding to that of a film of polyvinylbutyral (PVB) and equal to 35,100 J/m2 for a temperature of 20degreesC and for a tearing speed of 100 mm/min; (c) eref is the reference thickness that correspond to this PVB film and is equal to 0.38 mm.