Laminated glazing

Most laminated safety glazings are glass—PVB—glass trilayer composites, but bullet- and projectile-resistant laminates. Laminates for other specialty uses may be made with more than three layers. In addition to glass, poly (ethylene terephthalate) (PET), acrylic, and polycarbonate structural components (92) are used in specialty laminated glazing products. 

Solutia is one of the world s largest integrated producers of PA6.6. The integrated PA business accounts for around 5 8 % of Solutia s net sales. Solutia also claims to be the world s largest producer of PVB laminated glazing interlayers, a business which accounts for a further 22% (approximately), of net sales. 

Note that when laminated glazings are used, films can be deposited on inside sur ces (namely 2 or 3) that are protected from contact damage. 

The ASA (now ANSI) performance code for Safety Glazing Materials was revised in 1966 to incorporate these improvements in windshield constmction. The addition of test no. 26 requiring support of a 2.3-kg ball dropped from 3.7 m defined this level of improvement. It was based on a correlation estabUshed between 10-kg, instmmented, head-form impacts on windshields, on 0.6 x 0.9-m flat laminates, and the standard 0.3 x 0.3-m laminate with the 2.3-kg ball (28). Crash cases involving the two windshield interlayer types were matched for car impact speeds and were compared (29). The improved design produced fewer, less extensive, and less severe facial lacerations than those produced in the pre-1966 models. 

PVF film is now being used in the manufacture of weather-resisting laminates, for agricultural glazing and in electrical applications. 

Laminated safety glass has now become standard for automobile windscreens and is used for aircraft glazing. 

Most laminated safety glazings are glass-PVB-glass trilayer composites. Adhesion of plasticized PVB to clean glass is very high. 

Fig. 1. Wind-load data for heat-strengthened and laminated 3.2-mm glass. Architect s specified probability of breakage is 8/1000 laminates for a 1-min uniform wind-load duration. Four sides supported in weathertight rabbet. Curves for different glazing areas A, 0.93 m2 (10 ft2) B, 1.39 m2 (15 ft2) C, 1.86...

Laminated Glass. About 1.5 x 108 m2 of safety glazing interlayer was manufactured worldwide in 1994. About 75% of this was used for vehicle windshields and most of the rest was used for laminated architectural glazing (88,89) and a variety of security glass applications (90). Major producers of interlayer for laminated glass are Monsanto (Saflex), the largest producer, followed by DuPont (Butacite), Sekisui (S Lec) and Hbls (Trosofoil). 

Many grades of intedayer are produced to meet specific length, width, adhesion, stiffness, surface roughness, color (93,94), and other requirements of the laminator and end use. Sheet can be supplied with vinyl alcohol content from 15 to about 23 wt %, depending on the supplier and application. A common intedayer thickness for automobile windshields is 0.76 mm, but intedayer used for architectural or aircraft glazing applications, for example, may be much thinner or thicker. There are also special grades to bond rear-view mirrors to windshields (95,96) and to adhere the components of solar cells (97,98). Multilayer coextruded sheet, each component of which provides a separate property not possible in monolithic sheet, can also be made (99—101). 

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