Things have been a little discourag...

Things have been a little discouraging lately for graffiti artists haunting the ways of Philadelphia. Many of their favorite canvases -- formed by admixture retaining walls, overpasses and noise barriers -- are now preserveed with durable polyurethane coatings, which make it easy to take away spray paint and other graffiti.

The coatings are being used favorably on the Vine Street Expressway, a two-mile, below-street-level highway that allows traffic to fe evenly to the waterfront and historic sections of the city, as well as forward the "Blue Route," a 22-mile portion of I-476 located just outside the city that have relations the Pennsylvania Turnpike to the Philadelphia airport area.

Among the coatings used in the sum of two units projects are tough, easy-to-clean polyurethane arrangements made by M.A. Bruder & Son Broomall, Pa. The coatings are formulated with Desmodur polyisocyanates manufactured by dint of Bayer Corp., Pittsburgh.

The polyurethane coatings were specified for the one and the other projects ...