Automobile safety glass

Hie annual worldwide production of plastidzers is over 3 million tons, and the U.S. production is in excess of 1 million tons. In fact, plastidzers are major components of a number of polymer-containing products. For instance, the liner in automobile safety glass is composed mainly of polyvinyl butyral containing about 30% plastidzer. 

Automobile safety glass contains a sheet of polyvinyl polymer layered between two sheets of glass to prevent the formation of sharp fragments. 

Poly(vinyl acetals) find use in the areas of coatings [95] and adhesives [96] but their high cost has limited more widespread use. Poly(vinyl formals) are used as wire enamels [97] and are also combined with phenolics to increase toughness. Other resins have also been combined with poly(vinyl formal) to increase overload resistance [98]. Poly(vinyl butyral) is mainly used as an interlayer material in automobile safety glass and approximately 30 million lb was used in 1970 in the United States for this application [99]. 

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

Polyfvinyl butyral) is used as the plastic laminate in the preparation of automobile windshield safety glass. How would you synthesize this polymer ... 

The only but important engineering application for PVB is as an interlayer film between two glass plies to manufacture safety glass for the automobile and building industries. 

As automobiles became more common, so did the hazards of mud, rocks, etc., so that by 1904 windshields were introduced. These first windshields could be folded and removed if they were blocked by excessive mud. While the usefulness of the windshield was abundantly obvious, drivers found that they were dangerous during a wreck cutting passengers, drivers, and passers-by alike. Because the drivers were primarily believed to be responsible for automobile safety, most manufactures were slow to adopt safety glass. In 1919, Henry Ford addressed the windshield problem by having safety glass windshields on his automobiles. 

Lucite or plexiglas is used to make unbreakable lens, watch crystals, jewellery and safety glass for airplanes and automobiles. 

Chemically modified cellulose in the form of cellulose nitrate or nitrocellulose was made and tested for commercial applications in Britain in the 1855-1860 period without much success. The discovery by Hyatt, in 1863, that cellulose nitrate could be plasticized with camphor to give moldability to the blend, made this material much more useful. By 1870, celluloid (plasticized cellulose nitrate) was being produced into a variety of commercial products such as billiard balls, decorative boxes, and combs. Nitrocellulose was also soluble in organic solvents, unlike cellulose, and so could be applied to surfaces in solution to form a coating, as in airplane dopes and automobile lacquers. It could also be solution spun into fibers (synthetic silk) and formed into photographic film, or used as a laminating layer in early auto safety glass. It was also used as an explosive. The hazard introduced to many of these uses of nitrocellulose by its extremely flammable nature resulted in an interest to discover other cellulose derivatives that could still be easily formed, like nitrocellulose, but without its extreme fire hazard. 

Poly(vinyl butyral). The polymer poly(vinyl butyral) (PVB) was first used in automotive safety glass in 1938 to prevent flying glass resulting from automobile accidents and continues to be utilized in the twenty-first century for this purpose (Figure 19). 

Sinks, faucets, electrical switches, gears, aerosol bottles, meat hooks, lawn sprinklers, ballcocks, shaver cartridges, zippers, telephone push buttons Helmets, power tool housings, battery cases, safety glass, automobile lenses, 5-gal bottles... 

Most of the applications for vinyl acetate are mature. The strongest growth areas are in ethylene-vinyl alcohol, poly(vinyl butyral), and vinyl acetate-ethylene resins. Growth of use for ethylene-vinyl alcohol is expected at 10-15%/year through 2004. Poly(vinyl hutyral) is used in safety glass in automobile windshields. The U.S. market is mature for this use, hut has a potential as a replacement for tempered glass in Europe. A potential market exists for side and rear automobile windows worldwide (23). 

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