| 摘要 |
<p>1275653 Safety glass GLAVERBEL 15 Aug 1969 40891/69 Heading B5N [Also in Division C1] A laminate comprises as central layer polyvinylbutyral, and as outer layers glass strengthened by ion-exchange chemical tempering, the glass having a product of (i) thickness of internal tensile stress zone (in millimetres) and (ii) maximum internal tensile stress (expressed as optical birefringence retardation per unit length in millimicrons per millimetre), in the range of 10-140 millimicrons. Specification 1,274,733 is referred to.</p> |
